JP6748547B2 - High frequency power supply - Google Patents

Description

The present invention relates to a high frequency power supply device that supplies high frequency power to a load such as a plasma load.

As a high-frequency power supply device that supplies high-frequency power to a plasma load or the like, as shown in Patent Document 1, a variable DC power supply unit having a function of adjusting a DC output, and a DC output output from the variable DC power supply unit. And a DC/RF conversion unit (DC/RF conversion unit) for converting the switching element into a high frequency AC output by turning the switch element ON/OFF, and controlling the variable DC power supply unit to change the DC/RF conversion unit to a set value. The one that outputs the retained high-frequency power is used.

FIG. 16 shows a conventional high frequency power supply device 1 ′ of this type together with a load 2. The high frequency power supply device 1'shown in FIG. 16 includes a high frequency power generator 3'which generates high frequency power supplied to the load 2, an output impedance of the high frequency power generator 3', and an output terminal of the high frequency power generator 3'. And an impedance matching device 4 for matching the load impedance, which is the impedance seen from the load side.

The high frequency power generation unit 3'includes a variable DC power supply unit (variable DC power supply unit) 5'having a function of adjusting the magnitude of DC power to be output according to the output control signal Sdc, and a variable DC power supply unit 5'. A DC/RF converter (DC/high frequency converter) 6 for converting the output DC power into high frequency power, a low pass filter (LPF) 7 for removing harmonic components from the output of the DC/RF converter 6, and a low pass. The traveling wave power supplied to the load 2 on the output side of the filter 7 and the reflected wave power reflected by the load 2 and returned are detected, and a traveling wave power detection signal Pf and a reflected wave power detection signal Pr are output. The power detection unit 8 and the control unit 9'for controlling the variable DC power supply unit 5'and the DC/RF conversion unit 6 are provided.

The variable DC power supply unit 5 ′ is, for example, an AC-DC conversion unit that rectifies the output of the commercial power supply and converts it into a DC output, and converts the output of this AC-DC conversion unit into a DC voltage whose size is adjusted. And a DC-DC conversion unit that operates. The control unit 9′ controls the output of the DC-DC conversion unit so that the deviation between the target value of the high frequency power applied to the load and the traveling wave power detected by the power detection unit 8 becomes zero. The high frequency output applied to the load is controlled to match the target value.

The impedance matching device 4 matches the impedance (load impedance) viewed from the output end of the high frequency power generation unit 3′ with the load side regardless of the impedance of the load 2 to the output impedance of the high frequency power generation unit 3′. It is a device that functions to adjust (match). When the impedance matching device 4 adjusts the output impedance and the load impedance of the high frequency power generator 3'to a matching state, the high frequency power (traveling wave power) generated by the high frequency power generator 3'is applied to the load 2. It is absorbed efficiently.

The high-frequency power supply device 1'shown in FIG. 16 has a complicated configuration including an AC-DC conversion unit and a DC-DC conversion unit as a power supply unit in order to control the high-frequency power applied to the load. Since it is necessary to use the variable DC power supply unit 5', the cost is inevitably high.

Therefore, as shown in Patent Document 2, a high frequency power generation unit is configured by a DC power supply unit that generates a constant DC output and a DC-RF conversion unit that converts the output of this DC power supply unit into high frequency power. Then, it is conceivable that the DC-RF converter has a function of adjusting the output to control the high-frequency power supplied to the load.

FIG. 17 shows a structure of a high frequency power generator having such a structure. In FIG. 17, 5 is a DC power supply unit that outputs a constant DC voltage Vdc, and 6 is a DC/RF conversion unit that converts the output of the DC power supply unit 5 into a high frequency output.

In the example shown in FIG. 17, the leg of the reference phase including the series circuit of the high-side switch Q1 and the low-side switch Q2 and the leg of the control phase including the series circuit of the high-side switch Q3 and the low-side switch Q4 are connected in parallel. By being connected, a full bridge type switching circuit (inverter circuit) 6A is configured. In this switching circuit, the connection point a between the high side switch Q1 of the leg of the reference phase and the high side switch Q3 of the leg of the control phase, and the low side switch Q2 of the leg of the reference phase and the low side switch Q4 of the leg of the control phase. The connection point b serves as an input terminal of the switching circuit 6A, and the output voltage Vdc of the DC power supply unit 5 is input between these input terminals. In addition, the midpoint of the leg of the reference phase (connection point of the switches Q1 and Q2) consisting of the high-side switch Q1 and the low-side switch Q2, and the midpoint of the leg of the control phase consisting of the high-side switch Q3 and the low-side switch Q4 (switch A connection point d of Q3 and Q4 is an output terminal of the switching circuit 6A, and a series resonance circuit 6B composed of a series circuit of a reactor Lr and a capacitor Cr is inserted between the output terminals c and d to connect the transformer 6C. The primary winding W1 is connected. The switches Q1 to Q4 are configured by semiconductor switches that maintain an on state while a drive signal equal to or higher than a threshold value is applied and that turn off when the drive signal becomes lower than the threshold value. In the following description, the switches Q1 to Q4 are assumed to be composed of MOSFETs.

In FIG. 17, C1 to C4 are output capacitances provided in parallel at both ends of the switches Q1 to Q4, and D1 to D4 are feedback diodes connected in antiparallel to both ends of the switches Q1 to Q4. In the switching circuit shown in FIG. 17, the output capacitors C1 to C4 and the diodes D1 to D4 are used to realize soft switching of the switches Q1 to Q4. When the switches Q1 to Q4 are composed of semiconductor switching elements having a parasitic capacitance and a parasitic diode therein such as MOSFET, the parasitic capacitance and the parasitic diode are connected to the output capacitances C1 to C4 and the feedback diode D1. ~D4.

The load 2 is connected to both ends of the secondary winding W2 of the transformer 6C through a low-pass filter 7 including a reactor Lz and a capacitor Cz. Actually, a power detector and an impedance matching device are inserted between the low-pass filter 7 and the load, but they are not shown in FIG.

A switch driving unit provided in a control unit (not shown) between the gate and source of the MOSFET forming the high side switch Q1 of the leg of the reference phase of the switching circuit 6A and between the gate and source of the MOSFET forming the low side switch Q2. Are alternately applied with drive signals S1 and S2 of a predetermined level or higher. Ideally, the drive signals S1 and S2 are rectangular wave signals as schematically shown in FIG. 18A, and the levels of the drive signals S1 and S2 are equal to or higher than the threshold value. The high-side switch Q1 and the low-side switch Q2 are turned on when the MOSFETs are turned on and the levels of the drive signals S1 and S2 are below the threshold value (when the drive signals S1 and S2 disappear). The MOSFETs forming the side switch Q1 and the low side switch Q2 are turned off.

Similarly, between the gate and source of the MOSFET forming the high-side switch Q3 and the low-side switch Q4 of the leg of the control phase of the switching circuit 6A, the rectangular drive signal S3 and the rectangular-wave drive signal schematically shown in FIG. S4 is given. While the levels of the drive signals S3 and S4 are above the threshold, the MOSFETs configuring the high-side switch Q3 and the low-side switch Q4 are turned on, and the levels of the drive signals S3 and S4 are below the threshold. At this time, the MOSFETs forming the high-side switch Q3 and the low-side switch Q4 are turned off.

When the MOSFET is in a conductive state, a conduction loss is generated which is determined by the product of the square of the conduction current flowing between the drain and the source of the MOSFET and the ON resistance between the drain and the source (resistance at the time of ON). When the MOSFET is used as a switching element, it is necessary to operate the MOSFET in the saturation region when conducting to reduce the conduction loss as much as possible. Therefore, the crest values of the drive signals S1 to S4 given to the MOSFETs forming the switches Q1 to Q4 of the switching circuit 6A are set to be equal to or higher than the value required to bring the MOSFETs into the saturated state.

In the switching circuit 6A shown in FIG. 17, the leg of the reference phase including the series circuit of the high side switch Q1 and the low side switch Q2 and the leg of the control phase including the series circuit of the high side switch Q3 and the low side switch Q4 are DC. Since the output terminals of the power supply unit 5 are connected in parallel, if a period in which the switches forming each leg are simultaneously turned on occurs, the output of the DC power supply unit 5 is short-circuited, causing a large current to flow, and each switch Damages the MOSFETs that compose the. Therefore, the drive signal S2 applied to the low-side switch Q2 is extinguished between the timing of extinguishing the drive signal S1 applied to the high-side switch Q1 of the leg of the reference phase and the timing of applying the drive signal S2 to the low-side switch Q2. A dead time td is provided between the timing and the timing at which the drive signal of a predetermined level or higher is supplied to the high side switch Q1, and the supply of the drive signals S1 and S2 to both switches Q1 and Q2 is stopped during the dead time. There is a need to. Similarly, between the timing of extinguishing the drive signal S3 applied to the high side switch Q3 of the leg of the control phase and the timing of applying the drive signal S4 to the low side switch Q4, and extinguishing the drive signal S4 applied to the low side switch Q4. It is necessary to provide the dead time td between the timing of making it and the timing of giving the drive signal to the high side switch Q3.

In the DC/RF conversion unit 6 shown in FIG. 17, the dead phase, which is a period in which the supply of the drive signal to both the high-side switch and the low-side switch that configures each leg of the switching circuit 6A is suspended, After turning on the high side switch Q1 of the leg of the control leg, turning on the low side switch Q4 of the control phase leg, and turning on the low side switch Q2 of the reference phase leg, the control phase leg high By controlling the switches Q1 to Q4 so as to alternately perform the operation of turning on the side switch Q3, high frequency power is output from the DC/RF conversion unit 6.

The high frequency power supply device shown in FIG. 17 does not use a variable DC power supply unit having a complicated structure, but converts the DC power supply unit 5 that generates a constant DC output and the DC output of this DC power supply unit into high frequency power. Since the DC/RF conversion unit 6 is configured to operate, the device configuration can be simplified. The present invention is directed to a high frequency power supply device having such a configuration.

In the DC/RF conversion unit shown in FIG. 17, a series of operations from turning on the switch Q1 to turning on the switch Q1 again are as follows.
(1) After turning on the high side switch Q1 of the reference phase leg, turn on the low side switch Q4 of the control phase leg.
(2) While the control phase leg low side switch Q4 is on, the reference phase leg high side switch Q1 is turned off, and when the dead time has elapsed, the reference phase leg low side switch Q2 is turned on.
(3) After turning on the low side switch Q2 of the reference phase leg, turn off the low side switch Q4 of the control phase leg, and then turn on the high side switch Q3 of the control phase leg when the dead time elapses.
(4) Turn off the low side switch Q2 of the leg of the reference phase while the high side switch Q3 of the control phase is in the ON state, and turn on the high side switch Q1 of the leg of the reference phase when the dead time has passed.

In the DC/RF conversion unit 6 shown in FIG. 17, the current is passed through the output capacitance of each switch of each leg of the switching circuit and the inductor (circuit element having an inductance) existing in the DC/RF conversion unit 6. A charging/discharging circuit for charging and discharging the output capacitance of the switch of each leg is configured for each switch, and for each switch of each leg in the process of performing the above series of operations. The output capacitance of each switch is charged and discharged through a charging and discharging circuit configured as described above, and soft switching of each switch is performed. In the charging/discharging circuit configured for the switches of each leg, the output capacitance of each switch and the inductor existing in the DC/RF converter 6 are connected in series to form a series resonance circuit. Therefore, when charging/discharging the output capacitance of each switch, the current flowing through the charging/discharging circuit configured for each switch is the waveform current that forms a part of the DC resonance current (this current is It is called a resonance current). Although these operations are known, in order to facilitate understanding of the problems to be solved by the present invention, the outline of the operations will be described below.

When the drive signals S1 and S4 are applied to the high side switch Q1 of the leg of the reference phase and the low side switch Q4 of the leg of the control phase, these switches Q1 and Q4 are turned on. At this time, since a current flows through the inductor existing inside the DC/RF conversion unit 6, energy is accumulated in the inductor. In the high frequency power supply device shown in FIG. 17, the inductors existing in the DC/RF conversion unit 6 are the inductor Lr and the transformer 6C that form the series resonance circuit 6B.

After the drive signal S4 is applied to the low side switch Q4 of the leg of the control phase, the drive signal S1 applied to the high side switch Q1 of the leg of the reference phase is extinguished, and the switch Q1 is turned off. As the turn-off process of the switch Q1 progresses, the energy stored in the inductor existing in the DC/RF conversion unit 6 causes a partial resonance current to flow to charge the output capacitance C1 of the switch Q1. Increase the voltage across both ends linearly. As a result, the rise in the voltage across the switch Q1 is alleviated, and the switch Q1 is turned off by soft switching. Further, by charging the output capacitance C1 of the switch Q1, the diode D1 connected in anti-parallel to both ends of the switch Q1 is reverse biased so that no current flows through the diode D1.

In the process of charging the output capacitance C1 of the high side switch Q1 of the leg of the reference phase, the charge accumulated in the output capacitance C2 of the low side switch Q2 of the leg of the reference phase is transferred to the series resonance circuit 6B and the transformer. The partial resonance current is caused to flow through the charge/discharge circuit configured by the primary coil W1 of 6C and the low side switch Q4 of the leg of the control phase in the ON state. As a result, the voltage across the low-side switch Q2 of the leg of the reference phase to be turned on next is made zero, and the reverse bias of the diode D2 connected in antiparallel with the switch Q2 is released.

When the reverse bias of the diode D2 is released, the energy accumulated in the inductance of the circuit causes the diode D2 anti-parallel connected to the low side switch Q4 of the leg of the control phase and the leg low side switch of the reference phase in the ON state. Then, a forward current flows through the diode D2 through the charging/discharging circuit constituted by the series resonance circuit 6B and the primary coil W1 of the transformer 6C. Thereby, in the process of turning on the switch Q2, the voltage across the switch Q2 is maintained at substantially zero (the forward voltage of the diode D2).

As described above, when the low side switch Q2 of the leg of the reference phase is turned on, the output capacitance C2 of the switch Q2 is discharged, and a forward current is applied to the diode D2 connected in anti-parallel to both ends thereof. By causing the voltage to flow, the drive signal is given to the switch Q2 in a state where the voltage across the switch Q2 is substantially zero. As a result, the low side switch Q2 of the leg of the reference phase is turned on by ZVS (zero voltage switching) and ZCS (zero current switching).

After turning on the low side switch Q2 of the leg of the reference phase, the drive signal applied to the low side switch Q4 of the leg of the control phase is extinguished, and the turn-off operation of the switch Q4 is started. When the turn-off operation of the switch Q4 is started, the output capacitance C4 of the switch Q4 is charged by the primary current of the transformer 6C through the diode D2 and the switch Q2 and the inductor Ls. As a result, the voltage across the switch Q4 increases linearly, and the switch Q4 is turned off by soft switching. On the secondary side of the transformer 6C, the load current flowing through the closed circuit of the secondary coil W2-the inductor Lz-the load 2 and the capacitor Cz-the secondary coil W2 decreases. In the process of turning off the low side switch Q4 of the leg of the control phase, the output capacitance C3 of the high side switch Q3 of the leg of the control phase is discharged, so that the voltage across the switch Q3 decreases.

When discharging of the output capacitance C3 of the high side switch Q3 of the leg of the control phase is completed, the reverse bias of the diode D3 is released, so that the energy accumulated in the inductor Lr and the primary coil W1 of the transformer causes the inductor A forward current (partial resonance current) flows through the diode D3 in the path of Lr-primary coil W1-diode D3-DC power supply 5-diode D2 and switch Q2-inductor Lr. This forward current is a current (primary current of the transformer) in which the exciting current of the transformer is superimposed on the current induced in the primary coil of the transformer by the load current flowing in the secondary coil of the transformer 6C. The forward current flowing through the diode D3 causes the voltage across the switch Q3 to be almost zero.

The low side switch Q4 of the control phase leg is charged and the output capacitance C3 of the high side switch Q3 is discharged in the resonance mode only by the energy stored in the inductor Lr and the exciting inductance of the transformer when the load current flows. Done. Whether or not the output capacitance C4 is completely charged and the output capacitance C3 is completely discharged during the dead time period depends on the energy stored in the inductor Lr and the primary coil W1 of the transformer at the start of the resonance mode. Determined by When the energy stored in the inductor Lr and the exciting inductance of the transformer 6C is larger than the energy stored in the output capacitance C3 of the switch Q3, the output capacitance of the switch Q4 is fully charged and the switch Q3 is charged. A complete discharge of the output capacitance C3 is possible. Only when the output capacitance C3 of the switch Q3 is completely discharged, the switch Q3 can be turned on at ZVS and ZVC. The energy stored in the inductor Lr and the primary coil W1 of the transformer at the start of the resonance mode is determined by the current flowing in the inductor Lr and the primary coil W1 of the transformer until that time.

While the switches Q2 and Q3 are maintained in the ON state, the primary current of the transformer flows, the current flows through the inductor Lz and the load 2 on the secondary side of the transformer, and the power is supplied to the load 2. During this time, energy is accumulated in the inductor Lr on the primary side of the transformer, the exciting inductance of the transformer, and the inductor Lz of the filter circuit.

The DC/RF conversion unit 6 performs the same operation as above every half cycle, converts the output of the DC power supply 5 into high frequency power by the full bridge type switching circuit (inverter) 6A, and supplies it to the load 2. The power applied to the load 2 is the timing of turning on the switches Q1 and Q2 of the leg of the reference phase and the timing of turning on the switches Q4 and Q3 of the leg of the control phase diagonally located between the switches of the leg of the reference phase. The control is performed by changing the control phase angle φ in the range of 0° to 180° with the phase angle φ between them as the control phase angle.

An object of the present invention is to improve the efficiency of a high frequency power supply device having the configuration shown in FIG. In order to improve the efficiency of the high frequency power supply device shown in FIG. 17, it is necessary to minimize the loss generated in the high frequency power generation unit 6. Of the losses that occur in the high frequency power generator 6, the losses that occur in the switching circuit 6A are divided into conduction losses and switching losses. The conduction loss generated in the switches Q1, Q2, Q3, and Q4 is, as described above, between the ON resistance of the semiconductor switch (MOSFET in the above example) that constitutes each switch and the square of the current flowing through the switch. It is a loss determined by the product.

The ON resistance of a semiconductor switch such as a MOSFET depends on the voltage value of a drive signal applied to its control terminal, and can be minimized by setting the voltage value of the drive signal to a saturation voltage value or higher. Therefore, the conduction loss generated in the switches Q1 to Q4 can be reduced by operating the semiconductor switches in the saturation region with the voltage value of the drive signal given to the respective semiconductor switches being equal to or higher than the saturation voltage value.

The switching loss that occurs in the semiconductor switches that form the switches Q1 to Q4 is a loss that occurs when the semiconductor switch turns off and when it turns on, and occurs between both ends when the semiconductor switch turns off and when it turns on. The loss is determined by the product of the voltage (voltage between drain and source in the case of MOSFET) and the current flowing through the switch (current flowing between the drain and source in the case of MOSFET). This switching loss is due to the output capacitance (parasitic capacitance of the semiconductor switch or static capacitance of the capacitors connected to both ends of the semiconductor switch) when the semiconductor switches respectively configuring the switches Q1 to Q4 are turned off and turned on. (Capacitance) C1 to C4 is determined by how much charge is accumulated.

In order to minimize the switching loss that occurs in each switch of the switching circuit that constitutes the DC/RF conversion unit, the output capacitance of the switch that is turned off is charged and the output capacitance of the switch that is turned on next is discharged. Must be completed during the dead time. For that purpose, during the dead time, the partial resonance current for charging the output capacitance of the switch to be turned off and the partial resonance current for discharging the output capacitance of the switch to be turned on next. It is necessary to flush and. Since the partial resonance current for charging/discharging the output capacitances C1 and C2 of the high side switch Q1 and the low side switch Q2 of the leg of the reference phase is also the load current, when a sufficient current is supplied to the load. In the state where the output capacitances C1 and C2 can be completely charged and discharged during the dead time, and the electric charges remaining in the output capacitances of the switches Q1 and Q2 that are turned on are zero. , Switches can be turned on by soft switching by applying a drive signal to the switches Q1 and Q2.

On the other hand, the partial resonance current for charging/discharging the output capacitances C3, C4 of the switches Q3, Q4 of the control phase leg is controlled by the energy accumulated in the inductor existing in the circuit by the load current. Since it is a circulating current that flows between the leg of the reference phase and the leg of the reference phase, it has a sufficient size when the load current is flowing sufficiently and enough energy is stored in the inductor existing in the circuit. When is small, it is unavoidable that there is a shortage. Therefore, the phase angle φ between the timing of turning on each switch of the leg of the reference phase and the timing of turning on the switch of the leg of the control phase at the diagonal position of each switch of the leg of the reference phase is large, and the load current Is limited to a small value, it becomes impossible to completely charge and discharge the output capacitances C3, C4 of the switches Q3, Q4 of the leg of the control phase during the dead time. The switching operation at the time of turning on at the end of the period becomes hard switching, which causes a problem that a large switch loss occurs in these switches.

It should be noted that the partial resonance current for charging/discharging the output capacitance of each switch can be passed through the circuit including the output capacitance of each switch and the inductor existing in the DC/RF conversion unit. Only when the impedance of the circuit viewed from the midpoint of the leg of the circuit (from the output terminals c and d of the switching circuit) to the load side is inductive, and when the impedance is capacitive, the A partial resonance current for charging/discharging the output capacitance cannot be passed. Therefore, when the impedance of the circuit viewed from the output terminals c and d of the switching circuit as viewed from the load side is capacitive, the output capacitances C3 and C4 of the switches Q3 and Q4 are charged and discharged during the dead time. Therefore, when the switches Q3 and Q4 are turned on, a large amount of electric charge remains in the output capacitance of these switches, resulting in a large switching loss. Therefore, in a high-frequency power supply device using this type of DC/RF conversion unit, the impedance ZL viewed from the midpoint of the leg of the switching circuit of the DC/RF conversion unit to the load side is usually inductive. Is designed.

JP, 2003-143861, A International publication WO2011/013297

Generally, an impedance matching device provided between a high frequency power generating unit of a high frequency power supply device and a load controls a variable capacitor or a variable inductor, which is an impedance variable element, with a motor so that the impedance matching device has an input end and a load side. Since it is configured to perform the matching operation by adjusting the impedance, the impedance matching cannot be achieved instantaneously, and the impedance matching usually requires 100 msec to several seconds. Since reflection occurs at the load until impedance matching is achieved, the reflected wave power returning from the load 2 to the DC/RF conversion unit 6 increases. When the reflected wave power returning to the DC/RF conversion unit 6 increases, a partial resonance current for causing charging/discharging of the output capacitance of the switch forming the switching circuit of the DC/RF conversion unit 6 flows sufficiently. Therefore, the output capacitance of each switch cannot be sufficiently charged and discharged, and a large switching loss occurs when each switch is turned on.

In particular, when the load 2 that supplies high-frequency power is a plasma load, the impedance of the load 2 is unstable, and the applied power, the pressure of the gas in the chamber, the flow rate of the gas supplied to the chamber, the processing time, etc. Since the load impedance changes minutely depending on the condition (1), impedance mismatching frequently occurs.

In the high frequency power supply device including the DC/RF conversion unit 6 as shown in FIG. 17, the output impedance of the high frequency power generation unit 3 and the impedance when the load side is viewed from the output end of the high frequency power generation unit 3 (load impedance ) Is in a matching state with the output capacitances C1 and C2 of the switching elements Q1 and Q2 and the output capacitances C3 and C4 of the switching elements Q3 and Q4 during the dead time td. In addition, the circuit constants after the series resonance circuit 6B are set so as to minimize the switching loss generated in the switches Q1 to Q4. Therefore, when the output impedance of the high frequency power generator and the load impedance are in a mismatched state, the output capacitances C1 and C2 of the switches Q1 and Q2 and the output capacitances of the switches Q3 and Q4 during the dead time td. A state in which the charging and discharging of the capacitances C3 and C4 cannot be performed completely occurs, and the switching loss generated in the switches Q1 to Q4 increases.

Further, even when the output impedance of the high-frequency power generation unit 3 and the load impedance are in a matched state, the output of the high-frequency power generation unit 3 is suppressed to a low level, and the inductor in the circuit that constitutes the DC/RF conversion unit 6 is controlled. If sufficient energy is not stored, the output capacitance of each switch cannot be completely charged and discharged during the dead time, and switching loss may increase.

As described above, a DC power supply unit that generates a constant DC output, a DC/RF conversion unit that has a full bridge type switching circuit to which a constant DC voltage is input from the DC power supply unit, and a DC/RF conversion unit In order to output the high frequency power supplied to the load from the DC/RF conversion unit while providing the dead time which is a period in which the supply of the drive signal to both the high-side switch and the low-side switch forming each leg of the switching circuit is stopped, In a conventional high-frequency power supply device including a high-frequency power generation unit having a control unit that controls a switch of a switching circuit, a DC/RF conversion unit of a DC/RF conversion unit is caused by a change in load impedance or a decrease in load current. The switching loss that occurs in each switch that constitutes the switching circuit may increase, and the efficiency of the device may decrease.

Particularly, the partial resonance current that flows when the output capacitances C3 and C4 of the switches Q3 and Q4 of the control phase leg are charged and discharged is due to the energy accumulated in the inductor in the circuit when the load current flows. It is a circulating current that flows between the leg of the switch and the leg of the reference phase, and tends to run short when the load current is small.Therefore, the switching operation when turning on these switches at the end of the dead time period is hard switching. There is a problem that such a situation often occurs, a large switching loss occurs in these switches, and the efficiency of the device decreases.

Further, as described above, the high frequency power supply device shown in FIG. 17 performs switching when the impedance of the circuit seen from the midpoint of the leg of the switching circuit to the load side becomes capacitive depending on the load condition. The partial resonance current for charging and discharging the output capacitance of the switch of each leg of the circuit cannot be passed, but even in such a state, the switching loss when turning on each switch is minimized. In order to reduce the output capacitance, it is desirable to charge and discharge the output capacitance of each switch as much as possible.

An object of the present invention is to provide a high-frequency power generation unit that includes a DC power supply unit that generates a constant DC output and a DC/RF conversion unit that converts the DC output of the DC power supply unit into a high-frequency output. In the power supply device, charging/discharging of the output capacitance of each switch of the switching circuit of the DC/RF conversion unit can be performed as much as possible during the dead time to reduce the switching loss occurring in each switch of the switching circuit. To improve the efficiency of the apparatus further than ever before.

The present invention is provided with a DC power supply unit that generates a constant DC output and two legs in which a high-side switch and a low-side switch are connected in series to each other and the connection point of both switches is a middle point. A DC/RF conversion unit having a full-bridge type switching circuit having a configuration in which one leg and the other leg are used as a reference phase leg and a control phase leg, and both legs are connected in parallel between the output terminals of the DC power source unit; In order to output the high frequency power supplied to the load from the DC/RF conversion unit while providing the dead time which is a period in which the supply of the drive signal to both the high-side switch and the low-side switch forming each leg of the switching circuit is stopped, Operation of turning on the low side switch of the control phase leg after turning on the high side switch of the reference phase leg and turning on the low side switch of the reference phase leg after turning on the high side switch of the control phase leg And a high-frequency power generation unit having a control unit that controls a switch that configures a switching circuit so as to alternately perform an operation of turning on the power supply, and an impedance matching device inserted between the high-frequency power generation unit and the load. And a charging/discharging for causing a partial resonance current to flow through the output capacitance of each switch of each leg and the inductor existing in the DC/RF converter to charge and discharge the output capacitance of the switch of each leg. Intended for high frequency power supplies, where a circuit is configured for each switch.

The present specification discloses at least the following first to nineteenth inventions in order to achieve the above object in the high-frequency power supply device having the above-described configuration.
1st to 9th aspects of the present invention are described below, in which the switching operation of each switch in the leg of the control phase of the switching circuit in which the partial resonance current for charging and discharging the output capacitance tends to be particularly insufficient is hard. The purpose is to suppress the switching operation and reduce the switching loss.
Further, the tenth invention to the nineteenth invention suppresses not only the switching of the control phase leg switch but also the switching operation of the reference phase leg switch to be a hard switching operation, thereby further reducing the switching loss. Is aimed at. Hereinafter, configurations provided in the first invention to the nineteenth invention for solving these problems will be described together with their respective functions.

<First invention>
In the first invention, in order to achieve the above object, a capacitor voltage dividing circuit in which an output voltage of a DC power supply unit is applied to both ends, a voltage dividing point of the capacitor voltage dividing circuit, and a leg of a control phase of a switching circuit are provided. And an auxiliary reactor connected through a switch for an auxiliary circuit between the center point and the auxiliary circuit, and a supplementary current, which is superimposed on a partial resonance current flowing through a charge/discharge circuit configured for each switch of the control phase leg, is DC. The resonance auxiliary circuit that outputs from the power supply unit through the capacitor voltage dividing circuit, the auxiliary reactor, and the auxiliary circuit switch, and the charging and discharging of the output capacitance of the switch of the leg of the control phase without superimposing the supplementary current When the auxiliary circuit switch is held in the OFF state when it can be completed during the dead time, and the charging and discharging of the output capacitance of the switch of the leg of the control phase is performed without superimposing the supplementary current. An auxiliary circuit switch control unit is provided to control ON/OFF of the auxiliary circuit switch so that the auxiliary circuit switch is turned on when the auxiliary circuit switch cannot be completed during the dead time.

The auxiliary reactor causes partial resonance current to flow through the charge/discharge circuit configured for each switch of the leg of the control phase by the energy stored in the inductor (circuit element having an inductance) originally existing in the DC/RF converter. If the charging and discharging of the output capacitance of the switch on the leg of the control phase cannot be completed within the dead time period, the partial resonance current that flows through the charging and discharging circuit configured for each switch will be It is provided for superimposing the supplementary current, and is provided separately from the inductor originally present in the DC/RF conversion unit.

According to the first aspect of the invention, since the energy stored in the inductor existing in the DC/RF converter is small, only the partial resonance current flowing due to the energy causes the switch of the leg of the control phase during the dead time. When the charging and discharging of the output capacitance of can not be completed, by turning on the auxiliary circuit switch, the partial resonance current flowing through the charging and discharging circuit configured for each switch of the leg of the control phase. Since the replenishment current flowing from the DC power supply unit side through the auxiliary reactor can be superposed on, the charging and discharging of the output capacitance of each switch can be completed in the dead time period. Therefore, it is possible to increase the efficiency of the device by reducing the switching loss that occurs in each switch of the leg of the control phase in which the charging and discharging of the output capacitance tend to be incomplete (the switching loss tends to increase). ..

Further, in the present invention, the auxiliary circuit switch is turned on only when necessary and turned off when it is not necessary. Therefore, it is possible to prevent unnecessary conduction loss in the resonance auxiliary circuit and reduce switching loss caused in the switching circuit. The efficiency of the high-frequency power supply device can be improved.

<Second invention>
The second invention disclosed in the present application is applied to the first invention. In the present invention, the auxiliary circuit switch control section causes the partial resonance current to be generated by the energy stored in the inductor originally present in the DC/RF conversion section through the charge/discharge circuit configured for each switch of the control phase leg. When the charge and discharge of the output capacitance of the control phase leg switch cannot be completed during the dead time by simply flowing it, the auxiliary circuit switch is turned on, and each switch of the control phase leg is turned on. The charge/discharge of the output capacitance of the switch of the leg of the control phase can be performed in a dead time only by causing a partial resonance current to flow by the energy originally stored in the inductor originally existing in the DC/RF conversion unit through the charge/discharge circuit configured in the opposite direction. It is configured to turn off the auxiliary circuit switch when it is ready to be completed during the period.

<Third invention>
A third aspect of the present invention is applied to the first aspect of the present invention, in which the auxiliary circuit switch control unit determines whether or not impedance matching is achieved by an impedance matching device. And the auxiliary circuit switch is turned on when the matching state determining unit determines that the impedance is not matched, and the auxiliary circuit is turned on when the matching state determining unit determines that the impedance is matched. Switch control means for controlling the auxiliary circuit switch so as to turn off the auxiliary switch.

According to the present invention, when the impedance matching by the impedance matching device is not achieved and the partial resonance current for charging and discharging the output capacitance of the switch of the leg of the control phase tends to be insufficient, By turning on the auxiliary circuit switch, the resonance auxiliary circuit is connected to the middle point of the leg of the switching circuit, and the partial resonance for charging and discharging the output capacitance of the switch of the control phase leg is performed. Since the supplementary current can be superimposed on the current from the DC power supply side through the capacitor voltage dividing circuit and the auxiliary reactor, the charging and discharging of the output capacitance of the switch of the leg of the control phase can be completed during the dead time. The switches can be turned on and off by soft switching, and the switching loss generated in each switch can be reduced.

<Fourth invention>
The fourth invention is also applied to the first invention. In the present invention, the auxiliary circuit switch control unit sets the load current detection unit that detects the current supplied to the load from the high frequency power generation unit, and the average value or the effective value of the current detected by the load current detection unit. When it is less than the value, the auxiliary circuit switch is turned on, and when the average value or the effective value of the current detected by the load current detection means is equal to or more than the set value, the auxiliary circuit switch is turned off. And a switch control means for controlling the circuit switch.

With the above-mentioned configuration, is it possible to complete the charging/discharging of the output capacitance of the switch of the leg of the control phase in the dead time period by the energy stored in the inductor existing in the DC/RF conversion unit? Whether or not the auxiliary circuit switch is turned on/off can be appropriately determined by accurately determining whether or not the auxiliary circuit switch is turned on/off.

<Fifth Invention>
The fifth invention is also applied to the first invention. In the present invention, the auxiliary circuit switch control unit detects the circuit current flowing through the circuit between the midpoint of the leg of the reference phase and the midpoint of the leg of the control phase of the switching circuit, and circuit current detection means, When the average value or effective value of the current detected by the current detection means is less than the set value, the auxiliary circuit switch is turned on, and the average value or the effective value of the current detected by the circuit current detection means is equal to or greater than the set value. And a switch control means for controlling the auxiliary circuit switch so that the auxiliary circuit switch is turned off.

As described above, when the circuit current flowing through the circuit between the midpoint of the leg of the reference phase of the switching circuit and the midpoint of the leg of the control phase is detected, the current flowing through the inductor existing in the DC/RF conversion unit is detected. Therefore, a sufficient partial resonance current can flow when the output capacitance of the switch of the control phase leg is charged and discharged by the energy stored in the inductor originally existing in the DC/RF conversion unit. It is possible to accurately determine whether or not there is, and to appropriately control the auxiliary circuit switch.

<Sixth invention>
The sixth invention is also applied to the first invention. In the present invention, the auxiliary circuit switch control unit includes a matching state determination unit that determines whether or not impedance matching is achieved by the impedance matching unit, and a load that detects a current supplied from the high frequency power generation unit to the load. When the impedance matching is determined by the current detecting means and the matching state determining means, and the average value or the effective value of the current detected by the load current detecting means is equal to or more than the first set value, and the matching is performed. Although it is determined by the state determination means that the impedances are not matched, the auxiliary circuit switch is turned off when the average value or the effective value of the current detected by the load current detection means is equal to or more than the second set value. When it is determined that the impedance is matched by the matching state determination unit, but the average value or the effective value of the current detected by the load current detection unit is less than the first set value, and the matching is performed. The auxiliary circuit switch is turned on when it is determined by the state determination means that the impedance is not matched and the average value or effective value of the current detected by the load current detection means is less than the second set value. Switch control means for controlling the auxiliary circuit switch.

With the above-described configuration, the energy stored in the inductor originally present in the DC/RF conversion unit is insufficient when the impedance is not matched by the impedance matching device, so that each leg of the control phase is Not only when the partial resonance current that charges and discharges the output capacitance of the switch is insufficient, but the impedance is in a matched state, but because the control that limits the output of the high-frequency power generator is performed, the control phase Even when the partial resonance current for charging/discharging the output capacitance of each switch of the leg is insufficient, the replenishment current output from the DC power source side through the capacitor voltage dividing circuit and the auxiliary reactor is supplied to each control phase. By superimposing on the partial resonance current that flows when charging/discharging the output capacitance of the switch, the charging/discharging of the output capacitance of the switch on the leg of the control phase is completed during the dead time, and It is possible to reduce the switching loss generated in each switch.

<Seventh invention>
The seventh invention is also applied to the first invention. In the present invention, the auxiliary circuit switch control unit determines the matching state determining means for determining whether or not impedance matching is achieved by the impedance matching device, the midpoint of the reference phase leg of the switching circuit, and the control phase leg. The circuit current detection means for detecting the current flowing through the circuit between the center point and the middle point, and the average value of the currents detected by the circuit current detection means, which is determined by the matching state determination means to have impedance matching, or When the effective value is equal to or greater than the first set value and the matching state determination means determines that the impedance is not matched, the average value or the effective value of the current detected by the circuit current detection means is the first value. When it is equal to or more than the set value of 2, the auxiliary circuit switch is turned off, and the matching state determination means determines that the impedance is matched. However, the average value of the currents detected by the circuit current detection means or When the effective value is less than the first set value, and when the matching state determination means determines that the impedance is not matched, and the average value or the effective value of the current detected by the circuit current detection means is the second value. And a switch control means for controlling the auxiliary circuit switch so that the auxiliary circuit switch is turned on when the value is less than the set value.

With the above configuration, whether the auxiliary circuit switch is turned on based on both the impedance matching state by the impedance matching device and the magnitude of the current flowing through the charge/discharge circuit configured for each switch. The switch for the auxiliary circuit can be controlled by determining whether to turn it off.

<Eighth invention>
The eighth invention is also applied to the first invention. In the present invention, in addition to the constituent elements of the first invention, a parameter reflecting the current flowing through the circuit between the midpoint of the leg of the reference phase and the midpoint of the leg of the control phase of the switching circuit is detected. The auxiliary circuit switch control unit further includes a parameter detection unit, and the auxiliary circuit switch control unit stores an auxiliary circuit switch control table that gives a relationship between a parameter detected by the parameter detection unit and a state to be taken by the auxiliary circuit switch. By searching the control table for the storage means and the parameter detected by the parameter detection means, it is determined whether the state of the auxiliary circuit switch to be taken is the on state or the off state. And a switch control means for controlling the switch to be in a determined state.

Even in the case of the above configuration, when the partial resonance current flowing when charging/discharging the output capacitance of the switch of the control phase leg is insufficient, the auxiliary circuit switch is turned on/off to compensate for the insufficiency. Since it can be controlled, the charging and discharging of the output capacitance of each switch of the control phase leg can be completed during the dead time as much as possible to reduce the switching loss that occurs in each switch of the control phase leg. it can.

<Ninth Invention>
The ninth invention is applied to any one of the first to eighth inventions. In the present invention, the auxiliary circuit switch control unit of the auxiliary circuit switch control unit, further comprising load state determination means for determining the state of impedance viewed from the midpoint of the leg of the reference phase of the switching circuit and the midpoint of the leg of the control phase. The switch control means, when the load state determination means determines that the impedance seen from the midpoint of the leg of the reference phase of the switching circuit and the midpoint of the leg of the control phase to the load side is capacitive, It is configured to keep the auxiliary circuit switch on.

With the above-described configuration, even when the impedance when the load side is viewed from the midpoint of the leg of the reference phase and the midpoint of the control phase of the switching circuit of the DC/RF conversion unit is capacitive, a control phase is generated. Since the output capacitance of the leg switch can be charged and discharged to some extent, the switching loss that occurs when the impedance seen from the high frequency power generator to the load side becomes capacitive is Can be further reduced.

<Tenth Invention>
A tenth invention is directed to a high-frequency power supply device having the same configuration as the high-frequency power supply device targeted by the first invention.
In the present invention, the first auxiliary is provided between the capacitor voltage dividing circuit to which the output voltage of the DC power supply unit is applied to both ends, and the voltage dividing point of the capacitor voltage dividing circuit and the middle point of the leg of the control phase of the switching circuit. A second auxiliary circuit switch connected between the first auxiliary reactor connected through the circuit switch and the voltage dividing point of the capacitor voltage dividing circuit and the midpoint of the leg of the reference phase of the switching circuit. And a supplementary current superposed on a partial resonance current flowing through a charging/discharging circuit configured for each switch of the leg of the control phase, from the DC power supply unit to the capacitor voltage dividing circuit and the first auxiliary reactor. From the DC power supply unit, a supplementary current that is output through the auxiliary reactor and the first auxiliary circuit switch, and that is superimposed on the partial resonance current flowing through the charge/discharge circuit configured for each switch of the leg of the reference phase. A partial resonance current flowing through the resonance auxiliary circuit that outputs through the capacitor voltage dividing circuit, the second auxiliary reactor, and the second auxiliary circuit switch, and the charge/discharge circuit that is configured for each switch of the leg of the control phase. The first auxiliary circuit switch is turned off when charging/discharging of the output capacitance of each switch forming the leg of the control phase can be completed during the dead time without superimposing the supplementary current, If the supplemental current is not superimposed on the partial resonance current flowing through the charging/discharging circuit configured for each switch of the leg of the control phase, the charging/discharging of the output capacitance of each switch that configures the leg of the control phase is performed with a dead time. ON/OFF of the first auxiliary circuit switch is controlled so as to turn on the first auxiliary circuit switch when it cannot be completed in a period, and is configured for each switch of the reference phase leg. When the charging/discharging of the output capacitance of each switch forming the leg of the reference phase can be completed during the dead time without superimposing the supplementary current on the partial resonance current flowing through the charging/discharging circuit. Output of each switch forming the leg of the reference phase unless the supplementary current is superposed on the partial resonance current flowing through the charging/discharging circuit configured for each switch of the leg of the reference phase. Auxiliary circuit switch control for controlling on/off of the second auxiliary circuit switch so that the second auxiliary circuit switch is turned on when charging/discharging of the electrostatic capacitance cannot be completed during the dead time And a section are provided.

With the above configuration, the charge/discharge of the output capacitance of the switch of the leg of the control phase is completed during the dead time only with the partial resonance current flowing by the energy stored in the inductor originally existing in the DC/RF converter. A portion in which a replenishment current flowing from the DC power supply side through the capacitor voltage dividing circuit and the first auxiliary reactor is flowed when charging/discharging the output capacitance of the switch of the control phase leg when the state in which it is not possible occurs By superimposing on the resonance current, charging and discharging of the output capacitance of the switch of the control phase leg can be completed during the dead time, and due to the decrease of the load current, etc. When a state in which charging/discharging of the output capacitance of the leg switch cannot be completed occurs, the replenishment current flowing from the DC power source side through the capacitor voltage dividing circuit and the second auxiliary reactor is changed to the reference phase leg. By superimposing on the partial resonance current flowing when charging/discharging the output capacitance of the switch, the charging/discharging of the output capacitance of the switch of the reference phase leg can be completed in the dead time period. It is possible not only to reduce the switching loss that occurs in the control phase leg switch, but also to reduce the switching loss that occurs in the reference phase leg switch and further improve the efficiency of the device.

<Eleventh Invention>
The eleventh invention is also directed to a high frequency power supply device having the same configuration as the high frequency power supply device targeted by the first invention.
In the present invention, between the first capacitor voltage dividing circuit to which the output voltage of the DC power source unit is applied and the voltage dividing point of the first capacitor voltage dividing circuit and the middle point of the leg of the control phase of the switching circuit. A first auxiliary reactor connected through the first auxiliary circuit switch to the second auxiliary voltage divider circuit, and a voltage dividing point of the second capacitor voltage dividing circuit to which the output voltage of the DC power supply unit is applied to both ends. And a second auxiliary reactor connected through a second auxiliary circuit switch between the switching circuit and the midpoint of the leg of the reference phase of the switching circuit. The supplemental current superimposed on the partial resonance current flowing through the discharge circuit is output from the DC power supply unit through the first capacitor voltage dividing circuit, the first auxiliary reactor and the first auxiliary circuit switch, and each switch of the leg of the reference phase. Resonance for outputting a supplemental current superposed on a partial resonance current flowing through the charging/discharging circuit configured for the DC power supply unit through the second capacitor voltage dividing circuit, the second auxiliary reactor and the second auxiliary circuit switch. Even if the supplemental current is not superimposed on the partial resonance current flowing through the auxiliary circuit and the charging/discharging circuit configured for each switch of the control phase leg, the output capacitance of each switch configuring the leg of the control phase is charged. When the discharge can be completed during the dead time, the first auxiliary circuit switch is turned off, and the supplemental current is supplied to the partial resonance current flowing through the charge/discharge circuit configured for each switch of the control phase leg. The first auxiliary circuit switch is turned on when charging/discharging of the output capacitance of each switch forming the leg of the control phase cannot be completed during the dead time unless Each switch that controls the ON/OFF of the auxiliary circuit switch and that configures the leg of the reference phase without superposing the supplementary current on the partial resonance current that flows through the charge/discharge circuit configured for each switch of the leg of the reference phase. The second auxiliary circuit switch is turned off when the charging/discharging of the output capacitance can be completed during the dead time, and the charging/discharging circuit configured for each switch of the reference phase leg is The second auxiliary circuit switch is turned on when charging/discharging of the output capacitance of each switch forming the leg of the reference phase cannot be completed during the dead time unless the supplemental current is superimposed on the flowing partial resonance current. And an auxiliary circuit switch control unit for controlling on/off of the second auxiliary circuit switch so that the second auxiliary circuit switch is brought into the state.

According to an eleventh aspect of the invention, a first capacitor voltage dividing circuit and a second voltage dividing circuit to which an output voltage of the DC power source unit is applied are provided, and the DC power source unit and the first capacitor voltage dividing circuit are used. , A current source that outputs a supplemental current that is superimposed on a partial resonance current that charges and discharges the output capacitance of the switch of the control phase leg, and is configured by the DC power supply unit and the second capacitor voltage dividing circuit The configuration is the same as that of the tenth aspect of the invention, except that a current source that outputs a supplemental current that is superimposed on a partial resonance current that charges and discharges the output capacitance of the leg switch is configured. The control method and the function and effect of the power switch and the second auxiliary circuit switch are similar to those of the tenth invention.

<Twelfth Invention>
The twelfth invention is applied to the tenth invention or the eleventh invention. In the present invention, the auxiliary circuit switch control section causes the partial resonance current to be generated by the energy stored in the inductor originally present in the DC/RF conversion section through the charge/discharge circuit configured for each switch of the control phase leg. When the charging/discharging of the output capacitance of the switch of the control phase leg cannot be completed during the dead time by only flowing the current, the first auxiliary circuit switch is turned on to change the control phase leg The charge and discharge of the output capacitance of the switch of the leg of the control phase can be performed only by causing a partial resonance current to flow by the energy stored in the inductor originally existing in the DC/RF converter through the charge/discharge circuit configured for each switch. The switch for the first auxiliary circuit is turned off when the switch can be completed during the dead time, and the charge/discharge circuit configured for each switch of the leg of the reference phase is used to enter the DC/RF converter. When the charging and discharging of the output capacitance of the switch of the leg of the reference phase cannot be completed in the dead time period only by causing the partial resonance current to flow due to the energy accumulated in the originally existing inductor, the second The auxiliary circuit switch is turned on and the partial resonance current is caused to flow by the energy stored in the inductor originally present in the DC/RF converter through the charge/discharge circuit configured for each switch of the reference phase leg. It is configured to turn off the second auxiliary circuit switch when the charging and discharging of the output capacitance of the phase leg switch can be completed during the dead time.

According to the above configuration, when the charging and discharging of the output capacitance of each switch that configures the leg of the control phase of the switching circuit cannot be completed during the dead time, the DC power supply unit outputs the first auxiliary signal. A partial resonance current for charging/discharging the output capacitance of the switch of the control phase leg can be supplemented through the reactor and the first auxiliary circuit switch, and constitutes the leg of the reference phase of the switching circuit. When a state in which charging/discharging of the output capacitance of each switch cannot be completed during the dead time period occurs, the DC power supply unit switches the leg of the reference phase through the second auxiliary reactor and the second auxiliary circuit switch. Since the partial resonance current for charging and discharging the output capacitance of can be supplemented, the output capacitance of the control phase leg switch and the reference phase leg switch must be fully charged and discharged. Thus, it is possible to reduce the switching loss that occurs in each switch. In addition, when the partial resonance current for charging/discharging the output capacitance of the leg switch of the control phase can be sufficiently flown and for charging/discharging the output capacitance of the leg switch of the reference phase. When the partial resonance current of 1 can be sufficiently flown, the resonance auxiliary circuit can be separated from the switching circuit, so that the total loss generated in the DC/RF converter is prevented from increasing due to the loss generated in the resonance auxiliary circuit. You can

<Thirteenth invention>
The thirteenth invention is also applied to the tenth invention or the eleventh invention. In the present invention, the auxiliary circuit switch control unit determines that the impedance matching unit determines whether the impedance is matched, and the matching state determination unit determines that the impedance is not matched. The first and second auxiliary circuit switches are turned on, and when the matching state determining means determines that impedance matching is achieved, the first and second auxiliary circuit switches are turned on. Switch control means for controlling the first and second auxiliary circuit switches so as to be turned off.

With the above configuration, the partial resonance current for charging and discharging the output capacitance of the control phase leg switch is insufficient when the impedance matching device does not match the impedance. When it tends to occur, the partial resonance current for charging and discharging the output capacitance of the switch of the leg of the control phase is replenished from the DC power supply through the first auxiliary reactor and the first auxiliary circuit switch. When the partial resonance current for charging/discharging the output capacitance of the switch of the leg of the reference phase tends to be insufficient, the DC power supply unit can be connected to the second auxiliary reactor and the second auxiliary circuit. , The partial resonance current for charging and discharging the output capacitance of the reference phase leg switch can be replenished, so that the control phase leg switch and the reference phase By sufficiently charging and discharging the output capacitance of the leg switch, it is possible to reduce the switching loss that occurs in each switch. Also, when the impedance matching by impedance matcher is achieved, when the partial resonance current for charging/discharging the output capacitance of the leg switch of the control phase can be sufficiently flowed and the reference phase When the partial resonance current for charging/discharging the output capacitance of the leg switch can be sufficiently flown, the resonance auxiliary circuit can be separated from the switching circuit, so that the loss caused in the resonance auxiliary circuit causes DC. It is possible to prevent the total loss generated in the /RF converter from increasing.

<Fourteenth Invention>
The fourteenth invention is applied to the tenth invention or the eleventh invention. In the present invention, the auxiliary circuit switch control unit sets the load current detection unit that detects the current supplied to the load from the high frequency power generation unit, and the average value or the effective value of the current detected by the load current detection unit. When it is less than the value, the first and second auxiliary circuit switches are turned on, and when the average value or the effective value of the current detected by the load current detecting means is equal to or more than the set value, the first and the second Switch control means for controlling the first and second auxiliary circuit switches so as to turn off the second auxiliary circuit switch.

With the above configuration, it is determined whether or not a sufficient partial resonance current can flow when charging/discharging the output capacitance of the switch of the control phase leg, and the leg of the reference phase. It is possible to more accurately determine whether or not it is in a state in which a sufficient partial resonance current can flow when the output capacitance of the switch is charged and discharged, and the first and second auxiliary The circuit switches can be controlled appropriately.

<Fifteenth Invention>
The fifteenth invention is also applied to the tenth invention or the eleventh invention, and in the invention, the auxiliary circuit switch control unit controls the midpoint of the leg of the reference phase of the switching circuit and the leg of the control phase. Circuit current detecting means for detecting a current flowing through the circuit between the midpoint and a first auxiliary circuit switch when an average value or an effective value of the current detected by the circuit current detecting means is less than a set value. The first auxiliary circuit switch and the second auxiliary circuit switch are turned on when the second auxiliary circuit switch is turned on and the average value or the effective value of the current detected by the circuit current detection means is equal to or more than the set value. Switch control means for controlling the first auxiliary circuit switch and the second auxiliary circuit switch so as to turn off the switch.

With the above configuration, the energy stored in the inductor originally existing in the DC/RF converter allows a sufficient partial resonance current to flow when the output capacitance of the switch of the leg of the control phase is charged and discharged. It is possible to accurately determine whether or not it is in a ready state, and to appropriately control the auxiliary circuit switch.

<Sixteenth Invention>
The sixteenth invention is also applied to the tenth invention or the eleventh invention, and in the present invention, the auxiliary circuit switch control unit determines whether or not impedance matching is achieved by an impedance matching device. Matching state determining means, load current detecting means for detecting the current supplied from the high frequency power generator to the load, and matching state determining means determine that the impedance is matched, and the load current detecting means detects the impedance. When the average value or the effective value of the measured current is equal to or higher than the first set value, and the matching state determination means determines that the impedance is not matched, the current detected by the load current detection means When the average value or the effective value is equal to or more than the second set value, the first auxiliary circuit switch and the second auxiliary circuit switch are turned off, and the matching state determination means determines that the impedance is matched. However, when the average value or the effective value of the current detected by the load current detection means is less than the first set value, and the matching state determination means determines that the impedance is not matched, and the load The first and second auxiliary circuit switches are turned on when the average value or the effective value of the current detected by the current detection means is less than the second set value. And a switch control means for controlling the second auxiliary circuit switch.

According to the above-described configuration, the impedance existing in the DC/RF converter cannot be supplied to the load from the high-frequency power generator due to the impedance matching by the impedance matching device not being supplied to the load. Only when the stored energy is insufficient and the partial resonance current cannot flow sufficiently when charging and discharging the output capacitance of the control phase leg switch and the output capacitance of the reference phase leg switch. However, the impedance is in a matched state, but since the control for limiting the output of the high frequency power generation unit is performed, the energy accumulated in the inductor existing in the DC/RF conversion unit is insufficient, and the control phase Even when the partial resonance current that flows when charging and discharging the output capacitance of the leg switch and the output capacitance of the reference phase leg switch is insufficient, the first and second auxiliary circuit switches are used. In order to complete the charging/discharging of the output capacitance of the control phase leg switch and the charging/discharging of the output capacitance of the reference phase leg switch in the dead time period by turning it on, the control phase leg and reference The supplemental current is superimposed on the partial resonance current that charges and discharges the output capacitance of the phase leg switch, and the charge and discharge of the output capacitance of each switch can be completed during the dead time. Also, it is possible to reduce the switching loss that occurs in each switch of the reference phase. According to the present invention, compared to the case where it is determined whether or not the first and second auxiliary circuit switches are turned on only by determining whether or not the impedances match, it is possible to further improve the texture. It is possible to make fine control of.

<17th invention>
The seventeenth invention is also applied to the tenth invention or the eleventh invention. In the present invention, the auxiliary circuit switch control unit determines the matching state determining means for determining whether or not impedance matching is achieved by the impedance matching device, the midpoint of the reference phase leg of the switching circuit, and the control phase leg. The circuit current detection means for detecting the current flowing through the circuit between the center point and the middle point, and the average value of the currents detected by the circuit current detection means, which is determined by the matching state determination means to have impedance matching, or When the effective value is equal to or greater than the first set value and the matching state determination means determines that the impedance is not matched, the average value or the effective value of the current detected by the circuit current detection means is the first value. When it is equal to or more than the set value of 2, the first auxiliary circuit switch and the second auxiliary circuit switch are turned off, and it is determined by the matching state determination unit that the impedance is matched, When the average value or the effective value of the current detected by the circuit current detection means is less than the first set value, and the matching state determination means determines that the impedance is not matched, and the circuit current When the average value or the effective value of the current detected by the detection means is less than the second set value, the auxiliary is provided so as to turn on the first auxiliary circuit switch and the second auxiliary circuit switch. And a switch control means for controlling the circuit switch.

With the above configuration, the first and second auxiliary circuit switches are based on both the impedance matching state by the impedance matching device and the magnitude of the current flowing through the charging/discharging circuit configured for each switch. Since it is determined whether to turn on or off the switch, the first and second auxiliary circuit switches can be controlled more finely, and the first and second auxiliary circuit switches are unnecessarily turned on. Therefore, it is possible to prevent the conduction loss generated in the control phase leg switch and the reference phase leg switch from increasing.

<Eighteenth invention>
The eighteenth invention is also applied to the tenth invention or the eleventh invention. In the present invention, there is further provided a parameter detecting means for detecting a parameter reflecting the current flowing through the circuit between the midpoint of the leg of the reference phase of the switching circuit and the midpoint of the leg of the control phase, and for the auxiliary circuit. The switch control unit stores the auxiliary circuit switch control table that stores the relationship between the parameters detected by the parameter detection unit and the states that the first auxiliary circuit switch and the second auxiliary circuit switch should take. By searching the control table for the parameters detected by the table storage means and the parameter detection means, the first auxiliary circuit switch and the second auxiliary circuit switch are in the ON state or the OFF state. Switch control means for determining whether the state is the state and controlling the first auxiliary circuit switch and the second auxiliary circuit switch to be in the determined state.

Even in the case of the above configuration, the ON/OFF control of the first and second auxiliary circuit switches is appropriately performed to reduce the switching loss that occurs in the control phase leg switch and the reference phase leg switch. Can be measured.

<19th invention>
The nineteenth invention is applied to any of the tenth invention to the eighteenth invention. In the present invention, load state determination means for determining the state of impedance seen from the midpoint of the leg of the reference phase and the midpoint of the leg of the control phase of the switching circuit is further provided, and the auxiliary circuit switch control unit is provided. The switch control means of the auxiliary circuit when the load state determination means determines that the impedance seen from the midpoint of the leg of the reference phase and the midpoint of the leg of the control phase of the switching circuit to the load side is capacitive. Is configured to keep the power switch on.

With the above configuration, the first and second auxiliary circuit switches are activated when the impedance seen from the midpoint of the leg of the switching circuit of the DC/RF conversion unit to the load side shows capacitive. Can be turned on and off to charge and discharge the output capacitance of the control phase leg switch and charge and discharge of the reference phase leg output capacitance to some extent. It is possible to reduce the switching loss that occurs when the impedance looking at the side exhibits a state of being capacitive as compared with the conventional case.

According to the present invention, a DC power supply unit that generates a constant DC output and a full-bridge type switching circuit having a reference phase leg and a control phase leg are provided, and a constant DC voltage is input from the DC power supply unit. Supply to the load while providing a dead time that is a period in which supply of the drive signal to both the high-side switch and the low-side switch that configures each leg of the DC/RF conversion unit and the switching circuit of the DC/RF conversion unit is stopped. A high-frequency power supply unit having a control unit for controlling the switches of the DC/RF conversion unit that configures a switching circuit so that the high-frequency power to be output from the DC/RF conversion unit is provided. The output voltage of the capacitor is applied across the capacitor voltage divider circuit, and the auxiliary reactor connected through the auxiliary circuit switch between the voltage dividing point of this capacitor voltage divider circuit and the midpoint of the leg of the control phase of the switching circuit. By providing a resonance auxiliary circuit equipped with, the partial resonance current for charging and discharging the output capacitance of the switch of the control phase leg, the replenishment current output from the DC power supply section through the capacitor voltage dividing circuit and the auxiliary reactor Since they can be superimposed, the charge and discharge of the output capacitance of the control phase leg switch is completed in the dead time as much as possible to reduce the switching loss that occurs in the control phase leg switch. Therefore, it is possible to prevent the switching loss of the switch of the leg of the control phase from increasing and the efficiency of the device from decreasing when the load current decreases.

Further, according to the present invention, when there is no fear that the partial resonance current for charging/discharging the output capacitance of the switch of the leg of the control phase of the switching circuit will run short, the auxiliary circuit switch is turned off to set the resonance auxiliary circuit. Since it is possible to prevent unnecessary conduction loss from occurring, it is possible to effectively reduce the loss that occurs in the switching circuit and improve the efficiency of the high frequency power supply device.

In particular, according to the tenth to eighteenth inventions disclosed in the present application, the partial resonance current flowing when the output capacitance of the switch of the leg of the control phase of the switching circuit of the DC/RF conversion unit is charged/discharged. Not only can supplement current be superimposed on the partial resonance current when the partial resonance current is insufficient, but the partial resonance current that flows when charging and discharging the output capacitance of the switch of the reference phase leg is insufficient Since the supplementary current can be superimposed on the current, the partial resonance current that flows when charging and discharging the output capacitance of the switch of the leg of the reference phase is insufficient due to a decrease in the load current. Then, it is possible to prevent the switching efficiency from increasing and the efficiency of the device from decreasing.

Further, according to the ninth invention or the nineteenth invention, when the impedance seen from the midpoint of the leg of the switching circuit of the DC/RF conversion unit to the load side shows a capacitive state, the leg of the control phase is Since the output capacitance of the switch can be charged and discharged to some extent, switching loss that occurs when the impedance when the load side is seen from the high-frequency power generator shows a capacitive state Can be further reduced.

It is a block diagram showing the composition of one embodiment of the present invention. It is the block diagram which showed the structure of other embodiment of this invention. It is the block diagram which showed the structure of other embodiment of this invention. It is the block diagram which showed the structure of other embodiment of this invention. It is the block diagram which showed the structure of other embodiment of this invention. It is the block diagram which showed the structure of other embodiment of this invention. It is the block diagram which showed the structure of other embodiment of this invention. It is the block diagram which showed the structure of other embodiment of this invention. It is the block diagram which showed the structure of other embodiment of this invention. It is a circuit diagram showing an example of composition of a DC power supply section and a DC/RF conversion section which can be used in each embodiment of the present invention. FIG. 11 is a waveform diagram schematically showing a waveform of a drive signal applied to each switch of the leg of the control phase and a waveform of a current flowing through the auxiliary reactor in the circuit shown in FIG. 10. FIG. 6 is a circuit diagram showing another configuration example of a DC power supply unit and a DC/RF conversion unit that can be used in each embodiment of the present invention. It is a circuit diagram showing another example of composition of a DC power supply section and a DC/RF conversion section which can be used in each embodiment of the present invention. (A) thru|or (D) are the circuit diagrams which showed the various structural examples of the switch for auxiliary circuits which can be used in each embodiment of this invention. (A) And (B) is a circuit diagram showing another example of composition of a switch for auxiliary circuits which can be used in each embodiment of the present invention. It is the block diagram which showed the structure of the conventional high frequency power supply device provided with the variable DC power supply part and the DC/RF conversion part which converts the direct current output of this variable DC power supply part into a high frequency output. A circuit diagram showing a configuration example of a main part of a conventional high-frequency power supply device including a DC power supply unit that outputs a constant DC voltage and a DC/RF conversion unit that converts the DC output of the DC power supply unit into a high-frequency output. Is. (A) and (B) are waveforms of drive signals respectively applied to the leg switch of the reference phase and the leg switch of the control phase of the switching circuit constituting the DC/RF converter of the high frequency power supply device to which the present invention is applied. FIG. 3 is a waveform diagram schematically showing

The first to nineteenth embodiments of the present invention will be disclosed below. Of these embodiments, the first to ninth embodiments correspond to the first to ninth inventions, respectively, and a partial resonance current for charging and discharging the output capacitance is reduced. In particular, the purpose is to suppress the switching operation of each switch of the leg of the control phase of the switching circuit, which tends to be insufficient, to become a hard switching operation, and to reduce the switching loss.
Further, the tenth to nineteenth embodiments correspond to the tenth to nineteenth inventions, respectively. The switching operation of not only the control phase leg switch but also the reference phase leg switch is performed. The purpose is to further suppress the switching loss by suppressing the hard switching operation. Each embodiment will be described in detail below.

<First Embodiment>
Referring to FIG. 1, the configuration of a first embodiment of the present invention is shown in a block diagram. The circuit configuration of the main part of this embodiment is shown in FIG. The high frequency power supply device 1 shown in FIG. And an impedance matching device 4 for matching with a load impedance, which is an impedance, and a DC power supply unit 5 for generating a constant DC output. The configuration of each part will be described below.

In this embodiment, it is assumed that the load 2 is a plasma load. The plasma load is a load that generates plasma by high-frequency power supplied from the high-frequency power supply device 1, and is a plasma processing device or the like that performs processing such as etching by irradiating an object to be processed such as a semiconductor with plasma. The plasma load usually has an electrode for plasma generation inside the chamber and generates plasma when high frequency power is applied to the electrode. The impedance of the plasma load finely changes according to various conditions such as the magnitude of the electric power applied between the electrodes, the pressure of the gas in the chamber, the flow rate of the gas supplied into the chamber, and the time for generating plasma.

The impedance matching device 4 includes a variable capacitor or a variable inductor that is an impedance variable element, an operation mechanism that operates the impedance variable element using a motor as a driving source, and a means for detecting the impedance when the load side is viewed from the high frequency power generator. In order to maximize the high frequency power consumed by the load 2, the output impedance of the high frequency power generation unit 3 of the high frequency power supply device 1 and the impedance seen from the high frequency power generation unit 3 to the load side are provided. Adjust to match (conjugate). In general, the output impedance of the high-frequency power generator 3 is designed to be 50Ω, so the impedance matching device 3 operates so that the impedance seen from the high-frequency power generator 3 to the load side is equal to 50Ω.

The DC power supply unit 5 is a power supply unit that generates a constant DC output, and includes a rectifier that converts commercial AC power into DC power, a battery that is charged by a rectifier circuit with the output of the commercial power supply, and the like.

The high frequency power generation unit 3 includes a DC/RF conversion unit 6 that converts the DC output of the DC power supply unit 5 into a high frequency output, and a low-pass filter (LPF) 7 that removes harmonic components from the output of the DC/RF conversion unit 6. On the output side of the low-pass filter 7, a power detection unit 8 that detects the traveling wave power supplied to the load and the reflected wave power that returns from the load, and a control unit 9 that controls the DC/RF conversion unit 6 are provided. I have it. Although the high-frequency power generation unit 3 has these configurations as in the conventional high-frequency power supply device, in the present embodiment, the high-frequency power generation unit 3 additionally includes the resonance auxiliary circuit 10 and the auxiliary circuit switch control. And a section 11 are provided. Hereinafter, the configuration of each part of the high-frequency power generator 3 used in this embodiment will be described in detail.

The DC/RF conversion unit 6 includes a switching circuit 6A that performs a switching operation for converting the DC output of the DC power supply unit 5 into a high-frequency output, and a series resonance circuit 6B whose one end is connected to one output terminal of the switching circuit. The output of the switching circuit 6A includes a transformer 6C which is input to the primary coil W1 through the series resonance circuit 6B. The switching circuit 6A has a high-side switch and a low-side switch connected in series with each other, and a leg of a reference phase with the connection point of both switches as a middle point, and a high-side switch and a low-side switch also connected in series with each other. And a leg of a control phase having a connection point of both switches as a middle point and having a configuration in which both legs are connected in parallel between the output terminals of the DC power supply unit 5 There is. The DC/RF conversion unit 6 converts the DC output of the DC power supply unit 5 into a high frequency output by the switching operation of the switching circuit 6B, and outputs the converted high frequency output through the series resonance circuit 6B and the transformer 6C.

The switching circuit 6A used in this embodiment is configured, for example, as shown in FIG. The switching circuit 6A shown in FIG. 10 includes a high-side switch Q1, a low-side switch Q2 connected in series to the high-side switch, and a reference phase leg, a high-side switch Q3, and the high-side switch. A control phase leg composed of a low-side switch Q4 connected in series to the leg and both legs are connected in parallel between the output terminals of the DC power supply unit 5 have a full-bridge type configuration.

The high side switches Q1 and Q3 and the low side switches Q2 and Q4 are semiconductor switches. A semiconductor switch that constitutes each of the switches Q1 to Q4 is a semiconductor switch that is turned on when a drive signal of a predetermined level or more is applied between its control terminals and maintains an on state while the drive signal is applied to drive it. The one having the characteristic of turning off when the supply of the signal is stopped is used. In this embodiment, MOSFETs are used as the switches.

In the illustrated switching circuit 6A, the connection point a between the drain of the MOSFET forming the high side switch Q1 of the leg of the reference phase and the drain of the MOSFET forming the high side switch Q3 of the leg of the control phase, and the reference phase A connection point b between the source of the MOSFET forming the low side switch Q2 of the leg and the source of the MOSFET forming the low side switch Q4 of the control phase serves as an input terminal of the switching circuit 6A, and these input terminals a, The output voltage Vdc of the DC power supply unit 5 is input between b.

In addition, a connection point (the middle point of the leg of the reference phase) c between the source of the MOSFET that constitutes the high side switch Q1 of the leg of the reference phase and the drain of the MOSFET that constitutes the low side switch Q2 of the leg of the reference phase, and the control phase The connection point (the middle point of the leg of the control phase) between the source of the MOSFET forming the high side switch Q3 of the leg and the drain of the MOSFET forming the low side switch Q4 of the control phase leg is the output terminal of the switching circuit 6A. One output terminal c, which is the middle point of the leg of the reference phase, is connected to one end of a series resonance circuit 6B including a series circuit of an inductor Lr and a capacitor Cr.

The other end of the series resonance circuit 6B is connected to one end of the primary coil W1 of the transformer 6C, and the other end of the primary coil W1 of the transformer 6C is the other end of the switching circuit which is the midpoint of the leg of the control phase. It is connected to the output terminal d. One end e and the other end f of the secondary coil W2 of the transformer 6C are output terminals of the DC/RF conversion unit 6, and the high frequency power output from these output terminals e and f is input to the low pass filter 7. There is.

As shown in FIG. 10, for example, the low-pass filter 7 includes a reactor Lz whose one end is connected to one output terminal e of the DC/RF conversion unit 6, the other end of the reactor Lz, and the DC/RF conversion unit 6. Of the capacitor Cz connected to the other output terminal f of the high frequency power of the desired frequency obtained by removing the harmonic component from the high frequency power output from the DC/RF conversion unit 6. Output.

The gate-source (between control terminals) of the MOSFET forming the high-side switch Q1 of the reference phase leg and the gate-source of the MOSFET forming the low-side switch Q2 of the reference phase leg are respectively shown in FIG. The drive signals S1 and S2 are alternately applied from the switch drive unit provided in the control unit 9. These drive signals are similar to the drive signals S1 and S2 given to the switches Q1 and Q2 of the leg of the reference phase of the conventional DC/RF conversion unit shown in FIG. 17, and their respective waveforms are schematically shown. It is as shown in FIG.

In order to prevent the switches Q1 and Q2 from being turned on at the same time and short-circuiting the output of the DC power supply unit 5, the timing of extinguishing the drive signal applied to one of the switches Q1 and Q2 and the timing of applying the drive signal to the other A dead time td between the timing of extinguishing the drive signal applied to the other of the switches Q1 and Q2 and the timing of applying the drive signal to one of the switches Q1 and Q2, and the switches Q1 and Q2 are provided during the dead time. The supply of the drive signal to the device is stopped.

Similarly, between the gate and source (between control terminals) of the MOSFET forming the high side switch Q3 of the control phase leg and between the gate and source of the MOSFET forming the low side switch Q4 of the control phase leg, respectively, as shown in FIG. The drive signals S3 and S4 are alternately applied from the switch drive unit provided in the control unit 9 shown, as shown in FIG. In order to prevent the switches Q3 and Q4 of the leg of the control phase from being turned on at the same time and short-circuiting the output of the DC power supply unit 5, the drive signal applied to one of the switches Q3 and Q4 is extinguished and the other is driven. A dead time td is provided between the timing of applying the signal and the timing of extinguishing the drive signal applied to the other of the switches Q3 and Q4 and the timing of applying the drive signal to one of the switches Q3 and Q4. The supply of the drive signal to the switches Q3 and Q4 is stopped.

Note that in FIG. 10, the output capacitances C1 to C4 of the switches Q1 to Q4 and the feedback diodes D1 to D4 provided in antiparallel to both ends of each switch are omitted.

The power detection unit 8 shown in FIG. 1 is, on the output side of the low-pass filter 7, the traveling wave power applied to the load from the DC/RF conversion unit 5 through the low-pass filter 7 and the reflected wave power reflected and returned by the load. Is detected, and a traveling wave power detection signal Pf and a reflected wave power detection signal Pr having information on the traveling wave power and the reflected wave power are output. Since the structure of such a power detection unit is well known, its detailed description is omitted.

A control unit 9 is provided to control the switching circuit 6A of the DC/RF conversion unit 6. The control unit 9 receives the traveling wave power detection signal Pf and the reflected power detection signal Pr output from the power detection unit 8 as input, and drives the drive signal S1 to the high side switch Q1 and the low side switch Q2 of the leg of the reference phase of the switching circuit 6A, respectively. And S2, and the drive signals S3 and S4 to the high-side switch Q3 and the low-side switch Q4 of the leg of the control phase, respectively, so that the high-frequency power generator outputs high-frequency power of a predetermined magnitude. Cause the switching operation.

The control unit 9 converts the DC output of the DC power supply unit 5 into a high frequency output by supplying the drive signals S1 to S4 to the switches Q1 to Q4 so as to cause the switching circuit 6A to repeatedly perform the operation described in paragraph [0019]. The DC/RF converter 6 is caused to perform the operation. The high frequency power output from the DC/RF conversion unit 6 is supplied to the load 2 through the power detection unit 8 and the impedance matching unit 4 after the harmonic components are removed by the low pass filter 7.

The control unit 9 turns on the phase angle φ (the timing of turning on each switch of the leg of the reference phase and the timing of turning on each switch of the leg of the control phase in the diagonal position of each switch of the leg of the reference phase. (See FIG. 18) as a control phase angle, and changing the control phase angle φ in the range of 0° to 180° according to the detection signal output from the power detection unit 8 to supply high frequency to the load 2. Output control for keeping the traveling wave component of electric power at a set value, and DC when the reflected wave component detected by the power detection unit 8 exceeds a set specified value, the DC is controlled so as to keep the reflected wave component below a specified value. The reflection protection control that suppresses the output of the /RF converter 6 is performed.

As described in the description of the background art described above, this type of DC/RF conversion unit charges the output capacitance of the switch in which the supply of the drive signal is stopped at the start of the dead time and the dead time. Discharge of the output capacitance of the switch to which the drive signal is supplied at the end of the charging/discharging circuit including the output capacitance of each switch and the inductor originally present in the DC/RF converter 6 (series resonance circuit). ) Through the dead time period.

The "series resonance circuit" here is a resonance circuit that flows partial resonance current to charge and discharge the output capacitance of each switch.The output capacitance of each switch and the output capacitance of each switch are The series resonance circuit 6B shown in FIGS. 1 and 10 does not mean the series resonance circuit 6B itself, which is constituted by the capacitance and the inductance existing in the path through which the charging current or the discharging current of the capacitance flows.

In the illustrated example, the series resonance circuit 6B is used for the purpose of securing an inductor for forming a circuit (charging/discharging circuit) for charging/discharging the output capacitance of each switch and for cutting the DC component. Although the series resonance circuit 6B is omitted, a partial resonance current for charging and discharging the output capacitance of each switch is supplied by the inductance of the transformer 6C and the output capacitance of each switch. Even if a series resonance circuit is configured, the DC/RF converter can function. Further, the cut of the direct current component can be performed in the secondary side of the transformer 6C or in the low pass filter.

In order to reduce the switching loss that occurs in each switch of the switching circuit 6A, it is necessary to complete the charging/discharging of the output capacitance of each switch during the dead time period. As described in the section, when the impedance matching device 4 does not match the impedance, or when the energy originally stored in the inductor of the circuit of the DC/RF converter 6 is insufficient. In some cases, the partial resonance current flowing when charging/discharging the output capacitance of each switch may be insufficient, so charging/discharging of the output capacitance of each switch cannot be completed during the dead time. Sometimes. When such a situation occurs, it is impossible to turn off and turn on each switch by ZVS or ZCS, so that switching loss increases.

In particular, the partial resonance current flowing when the output capacitances C3, C4 of the switches Q3, Q4 of the control phase leg are charged and discharged is due to the energy accumulated in the inductor existing in the circuit due to the load current. Since this is a circulating current flowing between the leg of the reference phase and the leg of the reference phase, it tends to become insufficient when the load current is small. Therefore, it is preferable to take measures to prevent the partial resonance current for charging and discharging the output capacitances of each of the switches Q3 and Q4 of the leg of the control phase from becoming insufficient. ..

Therefore, in the present embodiment, as shown in FIGS. 1 and 10, the first voltage dividing capacitor Ca and the second voltage dividing capacitor Cb connected in series to the first voltage dividing capacitor are provided. A capacitor voltage dividing circuit 10A to which the output voltage of the DC power supply unit 5 is applied to both ends, a voltage dividing point of the capacitor voltage dividing circuit 10A (connection point of the voltage dividing capacitors Ca and Cb) 10a, and a control phase leg of the switching circuit 6A. And the auxiliary reactor 10B connected through the auxiliary circuit switch 10C capable of ON/OFF control to the middle point d of the control phase leg, and flows through the charge/discharge circuit configured for the leg switches Q3 and Q4. A resonance auxiliary circuit 10 that outputs a supplementary current that is superimposed on the partial resonance current from the DC power supply unit 5 through the capacitor voltage dividing circuit 10A, the auxiliary reactor 10B, and the auxiliary circuit switch 10C, and an auxiliary device that controls ON/OFF of the auxiliary circuit switch 10C. The circuit switch controller 11 is provided.

The auxiliary circuit switch controller 11 controls the leg switch of the control phase without superposing the supplementary current on the partial resonance current flowing through the charge/discharge circuit configured for the switches Q3 and Q4 of the leg of the control phase. When the charging/discharging of the output capacitance can be completed during the dead time td, the auxiliary circuit switch 10C is held in the OFF state, and the charging/discharging configured for the switches Q3 and Q4 of the leg of the control phase. For the auxiliary circuit when charging/discharging of the output capacitance of the switches Q3, Q4 of the leg of the control phase cannot be completed during the dead time td without superimposing the supplementary current on the partial resonance current flowing through the circuit. It is configured to control ON/OFF of the auxiliary circuit switch 10C so as to turn on the switch 10C.

Here, the first and second voltage dividing capacitors Ca and Cb forming the capacitor voltage dividing circuit 10A of the resonance auxiliary circuit 10 are capacitors having a sufficiently large electrostatic capacitance, and each voltage dividing capacitor is a DC power supply unit. 5 is equivalent to a voltage source that generates a voltage Vdc/2 that is 1/2 the output voltage Vdc.

When the auxiliary circuit switch 10C is in the ON state, the voltage Vdc/2 across the capacitor Ca or Cb of the voltage dividing circuit is applied across the auxiliary reactor 10B, but the voltage Vdc across the auxiliary reactor 10B. The polarity of /2 changes by turning on/off the switches Q3 and Q4 of the leg of the control phase of the switching circuit 10A. When the high side switch Q3 is in the ON state, the voltage Vdc/2 across the capacitor Ca is applied across the auxiliary reactor 10B so that the voltage dividing point 10a side of the capacitor voltage dividing circuit has a negative polarity, and the low side switch When Q4 is in the ON state, the voltage Vdc/2 across the capacitor Cb is applied across the auxiliary reactor 10B so that the voltage dividing point 10a side of the capacitor voltage dividing circuit has a positive polarity. When the voltage Vdc/2 across the first voltage dividing capacitor Ca is applied to the auxiliary reactor 10B, the voltage dividing point 10a side of the capacitor voltage dividing circuit 10A from the midpoint d of the leg of the control phase of the switching circuit 6A. When a voltage Idc (see FIG. 11C) having a polarity toward the flow direction and the voltage Vdc/2 across the second voltage dividing capacitor Cb is applied, the voltage of the voltage dividing point 10a of the voltage dividing circuit changes from the voltage dividing point 10a of the switching circuit 6A. A polar current ILb (see FIG. 11C) flows toward the midpoint d of the leg.

Therefore, when the auxiliary circuit switch 10C is in the ON state, the current flowing through the auxiliary reactor 10B becomes a triangular waveform current as shown in FIG. 11C, and the leg of the control phase is driven to the high side switch Q3. ILa flowing through the auxiliary reactor 10B during the dead time td1 from the stop of the supply of the signal S3 to the start of the supply of the drive signal S4 to the low side switch Q4 starts the turn-off operation at the start of the dead time td1. It is superimposed as a supplemental current on the partial resonance current that causes the output capacitance C3 of the switch Q3 to be charged and the output capacitance C4 of the switch Q4 that starts the turn-on operation at the end of the dead time td1 to be discharged.

Therefore, even if the energy stored in the inductor existing in the circuit in the DC/RF converter 6 is small, the output capacitance C3 of the high side switch Q3 is charged by turning on the auxiliary circuit switch 10C. The discharge of the output capacitance C4 of the low-side switch Q4 can be completed during the dead time td1 to reduce the switching loss generated in the switches Q3 and Q4.

Further, when the auxiliary circuit switch 10C is in the ON state, the dead time td2 from the stop of the supply of the drive signal S4 to the low side switch Q4 to the start of the supply of the drive signal S3 to the high side switch Q3. The current ILb flowing through the auxiliary reactor 10B charges the output capacitance C4 of the low-side switch Q4 which starts the turn-off operation at the start of the dead time td2 and the high-side switch Q3 which starts the turn-on operation at the end of the dead time td2. It is superimposed as a supplementary current on the partial resonance current flowing when the output capacitance C3 is discharged. Therefore, even if the energy stored in the inductor existing in the circuit in the DC/RF conversion unit 6 is small, if the auxiliary circuit switch 10C is turned on, the output capacitance C4 of the low side switch Q4 is charged. The discharge of the output capacitance C3 of the high-side switch Q3 can be completed during the dead time td2, and the switching loss generated in the switches Q3 and Q4 can be reduced.

However, in order to prevent unnecessary conduction loss due to the resonance auxiliary circuit 10, the auxiliary circuit switch 10C is connected so that the voltage dividing circuit 10A and the auxiliary reactor 10B of the resonance auxiliary circuit 10 are connected to the switching circuit only when necessary. Need to control.

Therefore, in order to improve the efficiency of the device, when the charging/discharging of the output capacitances C3, C4 of the switches Q3, Q4 of the leg of the control phase cannot be completed in a dead time period for some reason. To turn on the auxiliary circuit switch 10C and complete charging and discharging of the output capacitances C3, C4 of the control phase leg switches Q3, Q4 in a dead time without turning on the auxiliary circuit switch. When it is possible, it is necessary to control the auxiliary circuit switch 10C so as to turn off the auxiliary circuit switch.

When the partial resonance current flowing due to the energy stored in the inductor existing in the DC/RF conversion unit is insufficient, the current is replenished through the auxiliary reactor 10B to ensure the charging/discharging of the output capacitance of the switches Q3, Q4. To do so, it is necessary to start superimposing the supplementary current on the partial resonance current through the auxiliary reactor 10B before the timing when the dead time starts. Therefore, the auxiliary circuit switch 10C needs to be turned on before the start of each dead time.

However, if the auxiliary circuit switch 10C is held in the ON state during the period ts1 in which the switch Q3 is in the ON state and during the period ts2 in which the switch Q4 is in the ON state, the currents ILa and ILb are passed through the switches Q3 and Q4. Since the flow continues, it causes an increase in conduction loss in the switches Q3 and Q4. Therefore, when designing the DC/RF conversion unit 6, the auxiliary reactor 10B is designed to balance the reduced switching loss and the increased conduction loss and reduce the total loss generated in the switching circuit 6A. Set the inductance value.

In the case of the present embodiment, the auxiliary circuit switch control unit 11 controls the auxiliary reactor 10B without superimposing the supplementary current on the partial resonance current based on the state of the DC/RF conversion unit 6, the state of the load, and the like. Whether or not the charging/discharging of the output capacitances C3, C4 of the switches Q3, Q4 constituting the leg of the control phase can be completed during the dead time td (even if separated from the midpoint of the phase leg). It is necessary to provide a means for determining, but this determination should be performed based on the impedance matching state by the impedance matching device 4, the magnitude of the load current, the circuit current flowing through the circuit in the DC/RF converter, and the like. You can

According to the configuration of the present embodiment, the energy stored in the inductor existing in the DC/RF conversion unit 6 is small, and only the partial resonance current flowing by the energy causes the switch Q3 of the leg of the control phase during the dead time. When charging/discharging of the output capacitance of Q4 cannot be completed, by turning on the auxiliary circuit switch 10C, a portion flowing through the charging/discharging circuit configured for each switch of the leg of the control phase. Since the supplemental current flowing from the DC power supply unit 5 side through the capacitor voltage dividing circuit 10A and the auxiliary reactor 10B can be superimposed on the resonance current, charging and discharging of the output capacitance of the switches Q3 and Q4 is performed during the dead time. Can be completed. Therefore, it is possible to increase the efficiency of the device by reducing the switching loss that occurs in each switch of the leg of the control phase in which the charging and discharging of the output capacitance tend to be incomplete (the switching loss tends to increase). ..

When the energy stored in the inductor existing in the DC/RF converter is in a state in which the partial resonance current required to complete the charging/discharging of the output capacitance of each switch in the dead time period can flow. In addition, if the resonance auxiliary circuit is connected to the middle point of the leg of the control phase, the conduction loss increases due to the current flowing through each switch through the resonance auxiliary circuit, and the loss generated in the switching circuit rather increases. Occurs, and the advantage of reducing switching loss cannot be utilized. According to the present embodiment, the auxiliary circuit switch is turned on only when necessary and turned off when not needed, thus preventing the above problems from occurring and effectively reducing the loss occurring in the switching circuit. Therefore, the efficiency of the high frequency power supply device can be improved.

<Second Embodiment>
In the second embodiment of the present invention, the auxiliary circuit switch control unit 11 uses an inductor originally present in the DC/RF conversion unit through the charge/discharge circuit configured for the switches Q3 and Q4 of the control phase leg. It is assisted when the charging and discharging of the output capacitances C3 and C4 of the switches Q3 and Q4 of the leg of the control phase cannot be completed during the dead time td by just passing the partial resonance current by the stored energy. Control is performed only by turning on the circuit switch 10C and flowing a partial resonance current by the energy accumulated in the inductor originally present in the DC/RF conversion unit through the charge/discharge circuit configured for each switch of the control phase leg. The auxiliary circuit switch 10C is turned off when the charging and discharging of the output capacitances C3, C4 of the phase leg switches Q3, Q4 can be completed during the dead time. ..

The output of the switch of the leg of the control phase by simply passing a partial resonance current by the energy stored in the inductor originally existing in the circuit in the DC/RF converter through the charge/discharge circuit configured for each switch of the leg of the control phase Whether or not the charging and discharging of the capacitance can be completed during the dead time is determined by an appropriate parameter related to the energy stored in the inductor, such as load impedance or load current. This can be done by comparing the magnitude and the magnitude of the current flowing through the circuit in the DC/RF converter with the set value. The set value used for the determination can be experimentally determined.

The auxiliary circuit switch control unit 11 can have various configurations. In order to make it possible to complete the charging/discharging of the output capacitances of the switches Q3 and Q4 of the control phase leg in the dead time period, various types of auxiliary circuit switch control section 11 for controlling the auxiliary circuit switch 10C are controlled. A configuration example is shown in FIGS. 2 to 7 as a third chair eighth embodiment. In each of the embodiments shown in FIGS. 2 to 7, the circuit configurations of the switching circuit 6A, the series resonance circuit 6B, the transformer 6C, the low pass filter 7 and the resonance auxiliary circuit 10 are the same as those in the example shown in FIG.

<Third Embodiment>
FIG. 2 shows the configuration of the third embodiment of the present invention. In the present embodiment, the auxiliary circuit switch control unit 11 is configured to control the auxiliary circuit switch 10C according to the impedance matching state of the impedance matching device 4.

In the example shown in FIG. 2, the auxiliary circuit switch control unit 11 determines whether the impedance matching device 4 has matched the impedance, and the matching state determination unit 11A matches the impedance. The auxiliary circuit switch 10C is turned on when it is determined that the impedance is not taken, and the auxiliary circuit switch 10C is turned off when the impedance matching is determined by the matching state determination unit 11A. And a switch control means 11B for controlling the auxiliary circuit switch 10C. Other configurations are similar to those of the first embodiment.

The matching state determination unit 11A shown in FIG. 2 uses the traveling wave power detection signal Pf and the reflected wave power detection signal Pr output from the power detection unit 8 to determine whether or not impedance matching is achieved. It is configured. When the power detector 8 is configured to detect the absolute values of the traveling wave power and the reflected wave power, for example, the reflection coefficient | found from the detected value of the traveling wave power and the detected value of the reflected wave power | Matching status is determined so that impedance matching is determined when Γ| is less than or equal to the set value, and impedance matching is determined when reflection coefficient |Γ| exceeds the set value. Means 11A can be configured.

When the power detection unit 8 is configured to detect the vector values of the traveling wave and the reflected wave to detect the traveling wave power and the reflected wave power, the absolute value and the phase of the traveling wave and the reflected wave are detected. The matching state determination means can be configured to determine the load-side impedance, which is the impedance seen from the high-frequency power generator from the high-frequency power generation unit, and determine whether the impedance matching is achieved from the load-side impedance. ..

Further, the power detection unit 8 detects the voltage and current at the detection point, calculates the phase difference between the detected voltage and current, and then calculates the detected voltage and current and the calculated phase difference (phase difference between voltage and current). It is also possible to configure the matching state determination means 11A so as to obtain the load side impedance based on the above) and to determine whether or not the impedance is matched from the load side impedance.

Generally, in a high frequency power supply device, a power detection unit 8 for detecting a traveling wave component and a reflected wave component of the high frequency power is always provided at the output end of the high frequency power generation unit. It is possible to obtain the control information (information used to determine whether the auxiliary circuit switch is turned on or off) used for controlling the auxiliary circuit switch 10C without adding the sensor.

In the example shown in FIG. 2, the matching state determination unit 11A is configured to determine whether or not impedance matching is achieved using the output signal of the power detection unit 8. However, impedance matching is achieved. It can also be determined whether or not the load side impedance is obtained from the impedance matching device 4. In the example shown in FIG. 2, the matching state determination unit 11A is provided in the auxiliary circuit switch control unit 11, but whether impedance matching is achieved based on the load side impedance information obtained from the impedance matching unit 4. When determining whether or not it is possible to provide the matching state determination means in the impedance matching device 4.

When the matching state determination unit 11A as described above is provided, the switch control unit 11B switches the leg Q3 of the control phase leg of the switching circuit 6A when the matching state determination unit 11A determines that the impedances are not matched. , Q4, the charging/discharging of the output capacitances C3, C4 is considered to be impossible to complete during the dead time, the auxiliary circuit switch 10C is turned on, and the matching state determination means 11A matches the impedance. When it is determined that the charge is discharged, it is considered that the charging/discharging of the output capacitances C3, C4 of the switches Q3, Q4 can be completed in the dead time period, and the auxiliary circuit switch 10C is turned off. Can be configured to.

When the impedance matching by the impedance matching device 4 is not achieved, the partial resonance current for charging and discharging the output capacitance of each switch of the switching circuit 6A is often insufficient, and each switch is turned on. In this case, many switching losses often occur. According to the configuration of the present embodiment, when the impedance matching device 4 does not match the impedance, the output capacitances C3 and C4 of the switches Q3 and Q4 of the leg of the control phase are charged and discharged. By turning on the auxiliary circuit switch 10C when the partial resonance current for performing the operation tends to be insufficient, the auxiliary reactor 10B is placed in the leg of the voltage dividing point of the voltage dividing circuit 10A and the control phase of the switching circuit. A current flowing from the DC power supply unit 5 side through the capacitor voltage dividing circuit 10A and the auxiliary reactor 10B is connected to the point and the output capacitance C3 of the switches Q3 and Q4 of the leg of the control phase of the switching circuit 6A. Since it can be superimposed on the partial resonance current for charging/discharging C4, the charging/discharging of the output capacitances C3, C4 of the switches Q3, Q4 of the control phase leg is completed during the dead time, Each switch can be turned on and off by soft switching, and the switching loss generated in each switch can be reduced.

Further, in a state where impedance matching is achieved by the impedance matching device 4, the output electrostatic capacitance of each switch in the control phase is charged/discharged by the energy stored in the inductor existing in the DC/RF conversion unit 6. When the partial resonance current to be performed can be sufficiently flown, the auxiliary resonance circuit 10C can be separated from the switching circuit 6A by opening the auxiliary circuit switch 10C, so that the conduction loss generated in the auxiliary resonance circuit 10 causes a DC loss. It is possible to prevent the total loss generated in the /RF converter 6 from increasing.

<Fourth Embodiment>
FIG. 3 shows a fourth embodiment of the present invention. In the present embodiment, the auxiliary circuit switch control unit 11 detects the current supplied from the high frequency power generation unit 3 to the load 2 and the average of the currents detected by the load current detection unit 11C. When the value or the effective value is less than the set value, the auxiliary circuit switch 10C is turned on, and when the average value or the effective value of the current detected by the load current detecting means 11C is the set value or more, the auxiliary circuit switch is turned on. The switch control means 11B for controlling the auxiliary circuit switch 10C so as to turn off the switch 10C is provided. Other configurations are similar to those of the first embodiment.

The load current detection means 11C shown in FIG. 3 may be provided so as to obtain a detection signal including information on the current supplied to the load 2 from the high frequency power generator 3, but in the illustrated example, the low pass filter 7 is used. The load current detecting means 11C is provided so as to detect the current supplied to the load 2 from the output of the current sensor 12, which is provided with the current sensor 12 that detects the current flowing through the circuit that connects between the power detector 8 and the power detector 8. Has been done.

The magnitude of the partial resonance current flowing when the output capacitance of the switch of the leg of the control phase is charged/discharged is accumulated in the inductor included in the circuit due to the current flowing in the circuit in the DC/RF conversion unit. It depends on the amount of energy. The magnitude of the current flowing through the circuit in the high-frequency power generator corresponds to the average or effective value of the current supplied from the high-frequency power generator to the load. Therefore, with the above configuration, the energy stored in the inductor existing in the DC/RF conversion unit 6 charges and discharges the output capacitances of the switches Q3 and Q4 of the control phase leg during the dead time. It is possible to accurately determine whether or not it can be completed, and to control ON/OFF of the auxiliary circuit switch based on the determination result. The average value of the currents detected by the load current detection means 11C in order to determine whether the charging/discharging of the output capacitances of the switches Q3, Q4 of the leg of the control phase can be completed during the dead time period. Alternatively, the set value to be compared with the effective value can be experimentally determined.

<Fifth Embodiment>
FIG. 4 shows the configuration of the fifth embodiment of the present invention. In the present embodiment, the auxiliary circuit switch control unit 11 detects the circuit current flowing through the circuit between the midpoint c of the leg of the reference phase and the midpoint d of the leg of the control phase of the switching circuit 6A. When the average value or the effective value of the current detected by the detection means 11D and the circuit current detection means 11D is less than the set value, the auxiliary circuit switch 10C is turned on to detect the current detected by the circuit current detection means 11D. There is provided switch control means 11B for controlling the auxiliary circuit switch 11C so as to turn off the auxiliary circuit switch 10C when the average value or the effective value is equal to or more than the set value. Other configurations are similar to those of the first embodiment.

The amount of energy stored in the inductor originally present in the DC/RF converter 6 is determined by the amount of current flowing through the inductor. As in this embodiment, when the current flowing through the circuit between the midpoint of the leg of the reference phase and the midpoint of the leg of the control phase of the switching circuit 6A is detected, the current is detected through the inductor existing in the DC/RF conversion unit 6. Since the flowing current can be detected, the energy stored in the inductor originally existing in the circuit in the DC/RF conversion unit 6 charges the output capacitances C3, C4 of the switches Q3, Q4 of the leg of the control phase. It is possible to appropriately determine whether or not a sufficient partial resonance current can flow when discharging is performed, and it is possible to appropriately control the auxiliary circuit switch. The set value to be compared with the average value or the effective value of the current detected by the circuit current detecting means 11D can be experimentally determined.

<Sixth Embodiment>
FIG. 5 shows the configuration of the sixth embodiment of the present invention. In the present embodiment, whether or not the auxiliary circuit switch control unit 11 has achieved impedance matching by the impedance matching unit 4 based on the traveling wave power detection signal Pf and the reflected wave power detection signal Pr obtained from the power detection unit 8. It is determined by the matching state determination unit 11A that determines whether the impedance is matched, the load current detection unit 11C that detects the current supplied to the load from the high frequency power generation unit, and the matching state determination unit 11A that the impedance is matched. When the average value or the effective value of the current detected by the load current detection means 11C is equal to or higher than the first set value, and the matching state determination means 11A determines that the impedance is not matched, the load current When the average value or the effective value of the current detected by the detection means 11C is equal to or more than the second set value, the auxiliary circuit switch 10C is turned off, and the matching state determination means 11A determines that the impedance is matched. However, when the average value or the effective value of the current detected by the load current detection means 11C is less than the first set value, and the matching state determination means 11A determines that the impedance is not matched, Further, switch control for controlling the auxiliary circuit switch 10C so as to turn on the auxiliary circuit switch 10C when the average value or the effective value of the current detected by the load current detection means 11C is less than the second set value. And means 11B.

The first set value and the second set value may be the same or different. These set values are determined based on experimental results so as to minimize the switching loss generated in each switch of the switching circuit 6A. Other configurations are similar to those of the first embodiment.

With the configuration according to the present embodiment, the impedance matching by the impedance matching device 4 is not achieved, and the predetermined traveling-wave power cannot be supplied from the high-frequency power generator 3 to the load 2. Due to the energy stored in the inductor originally present in the /RF converter 6, it is only necessary to cause a partial resonance current to flow through the charging/discharging circuit configured for each switch of the control phase leg. , Q4 output capacitances C3, C4 cannot be charged and discharged in the dead time period, and impedance matching is achieved by the impedance matching device 4, but high frequency power supplied to the load 2 Since the control for limiting the electric power output from the high-frequency electric power generation unit 3 is performed in order to suppress the above, it is configured for each switch by the energy stored in the inductor originally existing in the DC/RF conversion unit 6. Even when it is not possible to complete the charging/discharging of the output capacitances C3, C4 of the switches Q3, Q4 forming the leg of the control phase by the partial resonance current flowing through the charging/discharging circuit during the dead time, By turning on the circuit switch 10C, the supplemental current is superimposed on the partial resonance current for charging/discharging the switch of the control phase leg, and the output capacitance of the control phase leg switches Q3 and Q4. Charging/discharging of C3 and C4 can be completed during the dead time.

Further, when configured as in the present embodiment, impedance matching is achieved by the impedance matching device 4 and sufficient traveling wave power is output from the high frequency power generator 3, so current is replenished through the auxiliary reactor 10B. Even if it does not, the partial resonance current necessary to complete the charging or discharging of the output capacitance of each switch during the dead time is passed through the charge/discharge circuit configured for each switch of the control phase leg. Not only when the impedance is not matched, but because the high-frequency power generator outputs a large amount of traveling wave power, the charging and discharging of the output capacitance of the switch of the leg of the control phase is performed. Even when the partial resonance current required for completing the resonance auxiliary circuit 10 in the dead time period can be flown, the auxiliary circuit switch 10C can be turned off to disconnect the resonance auxiliary circuit 10 from the switching circuit 6A. .. Therefore, according to the present embodiment, compared with the case where it is determined whether or not the auxiliary circuit switch 10C is turned on only by determining whether or not impedance matching by the impedance matching device 4 is achieved. Therefore, finer control can be performed.

<Seventh Embodiment>
FIG. 6 shows the configuration of the seventh embodiment of the present invention. In the present embodiment, whether or not the auxiliary circuit switch control unit 11 has achieved impedance matching by the impedance matching unit 4 based on the traveling wave detection signal Pf and the reflected wave detection signal Pr obtained from the power detection unit 8 A matching state determining means 11A, a circuit current detecting means 11D for detecting a current flowing through the circuit between the midpoint c of the leg of the reference phase of the switching circuit 6A and the midpoint d of the leg of the control phase, and the matching When the state determination means 11A determines that impedance matching is achieved, and the average value or effective value of the current detected by the circuit current detection means 11D is equal to or higher than the first set value, and the matching state determination means 11A. Although it is determined that the impedance is not matched, the auxiliary circuit switch is turned off when the average value or the effective value of the current detected by the circuit current detection means 11D is equal to or more than the second set value. When the matching state determination unit 11A determines that the impedance is matched, but the average value or the effective value of the current detected by the circuit current detection unit 11D is less than the first set value, and the matching When the state determination means 11A determines that the impedances are not matched and the average value or effective value of the current detected by the circuit current detection means 11D is less than the second set value, the auxiliary circuit switch is turned on. Switch control means 11B for controlling the auxiliary circuit switch so as to bring the switch into the state.

The illustrated circuit current detection means 11D uses the output of the current sensor 13 that detects the current flowing between the midpoint c of the leg of the reference phase of the switching circuit 6A and the series resonance circuit 6B to determine the reference phase of the switching circuit 6A. It is configured to detect the current flowing in the circuit between the midpoint c of the leg and the midpoint d of the leg of the control phase. The first set value and the second set value may be the same or different. These set values are determined based on experimental results so as to minimize the switching loss generated in each switch of the switching circuit 6A. Other configurations are the same as those in the first embodiment.

With the configuration according to the present embodiment, the auxiliary circuit switch 10C is turned on based on both the impedance matching state of the impedance matching device 4 and the magnitude of the current flowing through the charge/discharge circuit configured for each switch. Since it is determined whether to make the state or the off state, the control of the auxiliary circuit switch 10C can be performed more finely, and the auxiliary circuit switch 11C is unnecessarily turned on and generated by the leg switch of the control phase. It is possible to prevent the conduction loss from increasing.

<Eighth Embodiment>
FIG. 7 shows a seventh embodiment of the present invention. In this embodiment, the parameter detection means 14 for detecting the parameter reflecting the current flowing through the circuit between the midpoint of the leg of the reference phase and the midpoint of the leg of the control phase of the switching circuit 6A is provided, and the auxiliary The circuit switch control unit 11 includes a control table storage unit 11E that stores an auxiliary circuit switch control table that gives a relationship between a parameter detected by the parameter detection unit 14 and a state that the auxiliary circuit switch 10C should take. Whether the auxiliary circuit switch 10C should be in the on state or the off state by searching the control table stored in the control table storage means 11E for the parameter detected by the parameter detection means 14. And a switch control means 11B for controlling the auxiliary circuit switch 10C so as to bring the auxiliary circuit switch 10C into the determined state.

As a parameter reflecting the current flowing through the circuit between the midpoint of the leg of the reference phase and the midpoint of the leg of the control phase of the switching circuit 6A, the traveling wave power detection signal Pf output by the power detection unit 8 and A parameter that reflects the output voltage Vdc of the DC power supply unit 5 can be used. Other configurations are the same as those in the first embodiment.

According to the present embodiment, it is possible to accurately control ON/OFF of the auxiliary circuit switch by creating an appropriate auxiliary circuit switch control table based on the experimental result.

In the embodiment shown in FIG. 7, the auxiliary circuit switch control table stored in the control table storage means 11E is taken by the auxiliary circuit switch 10C and the load state detected from the output of the power detection unit 8. It can also be created to give a relationship with the power state. As the parameter indicating the state of the load detected from the output of the power detection unit 8, for example, the reflection coefficient and the load impedance can be used.

<Ninth Embodiment>
In the above-described first to seventh embodiments, a state in which the impedance viewed from the midpoint c of the leg of the reference phase of the switching circuit 6A and the midpoint d of the leg of the control phase to the load side becomes capacitive for some reason occurs. In such a case, a partial resonance current cannot flow in the charge/discharge circuit of the output capacitances C3, C4 of the switches Q3, Q4 of the control phase leg of the switching circuit, so that the switching operation of these switches is hard switching operation. Therefore, switching loss increases.

In the ninth embodiment of the present invention, in order to reduce the above switching loss, the impedance seen from the midpoint c of the leg of the reference phase of the switching circuit 6A and the midpoint d of the leg of the control phase to the load side. A load state determination means for determining the state of (load side impedance) is further provided, and when the load state detection means detects that the load side impedance is capacitive, the auxiliary circuit switch 10C is turned on. The switch control means 11B of the auxiliary circuit switch control unit 11 is configured so as to keep the above. The configuration of this embodiment can be applied to the case where the auxiliary circuit switch control unit has any of the configurations shown in the first to eighth embodiments.

In the circuit shown in FIG. 10, the currents ILa and ILb (see FIG. 11) flowing through the auxiliary reactor 10B are impedances (load side impedance) ahead of the midpoint d of the leg of the control phase of the switching circuit 6A (load side impedance). Output voltage Vdc of the DC power supply unit 5 and the inductance of the auxiliary reactor 10B. Therefore, even if the load side impedance is capacitive and the operation mode of the switching circuit 6A is originally the operation mode in which the output capacitances C3 and C4 of the switches Q3 and Q4 are not charged and discharged, the auxiliary circuit By turning on the switch 10C and connecting the resonance auxiliary circuit 10 to the midpoint d of the leg of the control phase of the switching circuit 6A, charging/discharging of the output capacitances C3, C4 of the switches Q3, Q4 of the control phase leg. Can be done to some extent.

With the above-described configuration, the impedance when the load side is viewed from the midpoint c of the leg of the reference phase and the midpoint c of the leg of the control phase of the switching circuit 6A of the DC/RF converter 6 is capacitive. Even if a state occurs, the output capacitance of the switch of the control phase leg can be charged and discharged to some extent, so that the impedance seen from the high-frequency power generator to the load side shows a capacitive state. It is possible to reduce the switching loss that occurs when the current level becomes lower than before.

In the first to ninth embodiments described above, the switches Q3 and Q4 of the leg of the control phase of the switching circuit, which tends to lack the partial resonance current for charging/discharging the output capacitances C3 and C4. The switching operation is suppressed from being a hard switching operation to reduce the switching loss. However, in the tenth to nineteenth embodiments described below, not only the switch of the control phase leg but also the reference phase leg is switched. The switching operation of the switches Q1 and Q2 is also suppressed from becoming a hard switching operation to further reduce the switching loss.

<Tenth Embodiment>
A block diagram showing the configuration of the tenth embodiment of the present invention is shown in FIG. 8, and a circuit diagram showing the circuit configuration of the main part is shown in FIG. In the embodiment shown in FIGS. 8 and 12, the capacitor voltage dividing circuit 10A is composed of a series circuit of capacitors Ca and Cb, and the output voltage of the DC power supply unit is applied to both ends of the capacitor voltage dividing circuit 10A and the capacitor voltage dividing circuit 10A. The first auxiliary reactor 10B1 connected through the first auxiliary circuit switch 10C1 between the voltage dividing point 10a and the midpoint d of the leg of the control phase of the switching circuit 6A, and the voltage dividing point of the capacitor voltage dividing circuit 10A. Resonance auxiliary circuit 10 including a second auxiliary reactor 10B2 connected through a second auxiliary circuit switch 10C2 between 10a and the midpoint c of the reference phase leg of the switching circuit 6A, and the control phase leg. Switch Q1, which controls the ON/OFF of the first auxiliary circuit switch 10C1 in order to complete the charging/discharging of the output capacitances C3, C4 of the switches Q3, Q4 during the dead time td, and which constitutes the leg of the reference phase. An auxiliary circuit switch control section 11 for controlling ON/OFF of the second auxiliary circuit switch 10C2 is provided in order to complete the charging/discharging of the output capacitances C1, C2 of Q2 during the dead time.

In this case, the auxiliary circuit switch control unit 11 configures the switch Q3 that configures the leg of the control phase without superimposing the supplemental current on the partial resonance current that flows through the charge/discharge circuit that is configured for each switch of the leg of the control phase. , Q4, when the charging/discharging of the output capacitance of Q4 can be completed during the dead time, the first auxiliary circuit switch 10C1 is turned off, and the charging/discharging configured for each switch of the leg of the control phase. The first auxiliary when the charging/discharging of the output capacitance of the switches Q3, Q4 forming the leg of the control phase cannot be completed during the dead time unless the supplemental current is superimposed on the partial resonance current flowing through the discharge circuit. ON/OFF of the first auxiliary circuit switch is controlled so as to turn on the circuit switch 10C1, and the supplementary current is superimposed on the partial resonance current flowing through the charge/discharge circuit configured for each switch of the leg of the reference phase. If the output capacitances of the switches Q1 and Q2 forming the leg of the reference phase can be completed during the dead time without doing so, the second auxiliary circuit switch 10C2 is turned off to set the reference If the supplemental current is not superimposed on the partial resonance current flowing through the charging/discharging circuit configured for each switch of the phase leg, the charging/discharging of the output capacitance of the switches Q1, Q2 configuring the leg of the reference phase is performed in the dead time. The ON/OFF of the second auxiliary circuit switch 10C2 is controlled so that the second auxiliary circuit switch 10C2 is turned on when it cannot be completed within the period. Other configurations are similar to those of the first embodiment.

According to the configuration of the present embodiment, the current (load current) supplied from the high frequency power supply device 1 to the load 2 is small, and the energy stored in the inductor in the circuit of the DC/RF conversion unit 6 is small. , The state where the charge/discharge of the output capacitances of the switches Q3 and Q4 of the leg of the control phase cannot be completed only by the partial resonance current flowing due to the energy accumulated in the inductor originally existing in the DC/RF converter. Even if it occurs, by turning on the first auxiliary circuit switch 10C1, the current flowing from the DC power supply unit 5 side through the capacitor voltage dividing circuit 10 and the first auxiliary reactor 10B1 is controlled to the leg of the control phase. Of the output capacitances of the switches Q3 and Q4 are superposed on the partial resonance current to charge and discharge the output capacitances of the control phase leg switches Q3 and Q4 to charge and discharge the output capacitances C3 and C4 of the dead time td. In addition to the above, the load current almost stops flowing due to the reason that the impedance of the load 2 becomes extremely large, and the energy stored in the inductor originally present in the DC/RF converter flows. When a state in which the charging and discharging of the output capacitances C1 and C2 of the switches Q1 and Q2 of the legs of the reference phase cannot be completed by the partial resonance current alone during the dead time, the capacitor is connected from the DC power supply unit 5 side. Since the current flowing through the voltage dividing circuit 10 and the second auxiliary reactor 10B2 can be superimposed on the partial resonance current for charging/discharging the output capacitances C1, C2 of the switches Q1, Q2 of the legs of the reference phase, It is possible to prevent a large switching loss from occurring in the switch of the leg of the reference phase when the load current is suppressed.

<Eleventh Embodiment>
A block diagram showing a configuration of the eleventh embodiment of the present invention is shown in FIG. 9, and a circuit configuration of a main part is shown in FIG. In the present embodiment, a first capacitor voltage dividing circuit 10A1 having capacitors Ca1 and Cb1 connected in series with each other and having the output voltage of the DC power supply unit 5 applied to both ends, and the first capacitor voltage dividing circuit 10A1. A first auxiliary resonance equipped with a first auxiliary reactor 10B1 connected through a first auxiliary circuit switch 10C1 between the voltage dividing point 10a1 of the circuit 10A1 and the midpoint d of the leg of the control phase of the switching circuit 6A. A second capacitor voltage dividing circuit 10A2 and a second capacitor voltage dividing circuit 10A2, which is composed of a circuit configuration unit 10-1 and capacitors Ca2 and Cb2 connected in series with each other, to which the output voltage of the DC power supply unit 5 is applied. A second auxiliary equipped with a second auxiliary reactor 10B2 connected through a second auxiliary circuit switch 10C2 between the voltage dividing point 10a2 of the pressure circuit 10A2 and the midpoint c of the leg of the reference phase of the switching circuit 6A. The resonance auxiliary circuit 10 constituted by the resonance circuit forming section 10-2 and the charge/discharge of the output capacitances C3, C4 of the switches Q3, Q4 of the leg of the control phase are completed in the dead time td. Second auxiliary circuit switch for controlling the ON/OFF of the auxiliary circuit switch 10C1 and completing the charging/discharging of the output capacitances C1, C2 of the switches Q1, Q2 forming the leg of the reference phase in the dead time period. An auxiliary circuit switch controller 11 for controlling ON/OFF of 10C2 is provided.

Also in this case, the auxiliary circuit switch control unit 11 configures the switch forming the leg of the control phase without superposing the supplementary current on the partial resonance current flowing through the charge/discharge circuit formed for each switch of the leg of the control phase. When the charging/discharging of the output capacitances of Q3 and Q4 can be completed during the dead time, the first auxiliary circuit switch 10C1 is turned off, and each switch of the leg of the control phase is configured. When the charging/discharging of the output capacitances of the switches Q3, Q4 forming the leg of the control phase cannot be completed during the dead time unless the supplemental current is superimposed on the partial resonance current flowing through the charging/discharging circuit, the first ON/OFF of the first auxiliary circuit switch is controlled so that the auxiliary circuit switch 10C1 is turned on, and a supplemental current is supplied to the partial resonance current flowing through the charge/discharge circuit configured for each switch of the leg of the reference phase. The second auxiliary circuit switch 10C2 is turned off when charging/discharging of the output capacitances of the switches Q1 and Q2 forming the leg of the reference phase can be completed during the dead time without superimposing. Dead time for charging/discharging the output capacitance of the switches Q1 and Q2 forming the leg of the reference phase unless the supplemental current is superimposed on the partial resonance current flowing through the charge/discharge circuit formed for each switch of the leg of the reference phase. The ON/OFF of the second auxiliary circuit switch 10C2 is controlled so that the second auxiliary circuit switch 10C2 is turned on when the second auxiliary circuit switch 10C2 cannot be completed during the period. Other configurations are similar to those of the first embodiment.

The configuration of the present embodiment is provided with the first capacitor voltage dividing circuit 10A1 and the second voltage dividing circuit 10A2 to which the output voltage of the DC power supply unit 5 is applied, and the DC power supply unit 5 and the first capacitor voltage dividing circuit 10A2 are provided. The circuit 10A1 constitutes a current source for outputting a current superimposed on the partial resonance current for charging/discharging the output capacitances C3, C4 of the switches Q3, Q4 of the control phase leg, and the DC power supply unit 5 and the second power source. With the exception of the point that a current source that outputs a current superimposed on a partial resonance current that charges and discharges the output capacitances C1 and C2 of the switches Q1 and Q2 of the legs of the reference phase is configured by the capacitor voltage dividing circuit 10A2 of Similar to the eighth embodiment, the first auxiliary circuit switch 10C1 and the second auxiliary circuit switch 10C2 are controlled in the same manner as in the eighth embodiment.

As shown in FIG. 8 or FIG. 9, the first auxiliary reactor 10B1 is used to obtain a current superimposed on a partial resonance current for charging/discharging the output capacitances C3, C4 of the switches Q3, Q4 of the leg of the control phase. And the first auxiliary circuit switch 10C1 are provided, and in order to obtain a current superimposed on the partial resonance current for charging and discharging the output capacitances C1 and C2 of the switches Q1 and Q2 of the legs of the reference phase, the second In any case where the auxiliary reactor 10B2 and the second auxiliary circuit switch 10C2 are provided, an auxiliary circuit switch control unit for controlling the first auxiliary circuit switch 10C1 and the second auxiliary circuit switch 10C2 11 can have the same configuration as that shown in each of the first to ninth embodiments.

Hereinafter, like the tenth embodiment shown in FIG. 8 and the eleventh embodiment shown in FIG. 9, a portion for charging/discharging the output electrostatic capacitances C3, C4 of the switches Q3, Q4 of the leg of the control phase. A first auxiliary reactor 10B1 and a first auxiliary circuit switch 10C1 are provided in order to obtain a current superimposed on the resonance current, and charge and discharge of the output capacitances C1 and C2 of the reference phase leg switches Q1 and Q2 are performed. Various configuration examples of the auxiliary circuit switch control unit 11 used when the second auxiliary reactor 10B2 and the second auxiliary circuit switch 10C2 are provided in order to obtain the current superposed on the partial resonance current are shown. The respective configurations are shown below as the twelfth to nineteenth embodiments.

<Twelfth Embodiment>
In the present embodiment, the auxiliary circuit switch control unit 11 shown in FIG. 8 or 9 originally exists in the DC/RF conversion unit through the charge/discharge circuit configured for each switch of the leg of the control phase. When the charging/discharging of the output capacitances C3, C4 of the switches Q3, Q4 of the leg of the control phase cannot be completed in the dead time period only by causing the partial resonance current to flow by the energy stored in the inductor. The first auxiliary circuit switch 10C1 is turned on, and the energy stored in the inductor originally present in the DC/RF converter 6 is passed through the charge/discharge circuit configured for the control phase leg switches Q3 and Q4. When the charge/discharge of the output capacitance of the switches Q3, Q4 of the leg of the control phase can be completed within the dead time td by simply passing the partial resonance current, the first auxiliary circuit switch 10C1 is switched on. If only the partial resonance current is caused to flow by the energy stored in the inductor originally present in the DC/RF conversion unit 6 through the charge/discharge circuit configured for the switches Q1 and Q2 of the legs of the reference phase in the off state. When the charging and discharging of the output capacitances C1 and C2 of the leg switches Q1 and Q2 cannot be completed in the dead time period, the second auxiliary circuit switch 10C2 is turned on to set the reference phase The partial resonance current is caused to flow by the energy stored in the inductor originally existing in the DC/RF converter 6 through the charge/discharge circuit configured for the leg switches Q1 and Q2, and the leg phase switches Q1 and Q2 of the reference phase. The second auxiliary circuit switch 10C2 is turned off when the charging and discharging of the output electrostatic capacitances C1 and C2 can be completed during the dead time. Other configurations are similar to those of the tenth embodiment or the eleventh embodiment.

According to the configuration of the present embodiment, when the charging/discharging of the output capacitances C3, C4 of the switches Q3, Q4 forming the leg of the control phase of the switching circuit 6A cannot be completed during the dead time td. The partial resonance current for charging/discharging the output capacitances C3, C4 of the switches Q3, Q4 of the control phase leg from the DC power supply unit 5 to the first auxiliary reactor 10B1 and the first auxiliary circuit. The supplementary current can be superposed through the switch 10C1 and the charging and discharging of the output capacitances C1 and C2 of the switches Q1 and Q2 forming the leg of the reference phase of the switching circuit 6A cannot be completed in the dead time period. When it occurs, the DC power supply unit 5 supplies the second auxiliary reactor 10B2 and the second auxiliary circuit to the partial resonance current for charging and discharging the output capacitances C1 and C2 of the reference phase leg switches Q1 and Q2. Since the replenishment current can be superimposed through the switch 10C2, the output capacitances C3 and C4 of the control phase leg switches Q3 and Q4 and the output capacitances C1 and C2 of the reference phase leg switches Q1 and Q2. The charge/discharge can be completed in the dead time period to reduce the switching loss that occurs in the control phase leg switches Q3 and Q4 and the reference phase leg switches Q1 and Q2.

Further, when the partial resonance current for charging/discharging the output capacitances C3, C4 of the control phase leg switches Q3, Q4 can be sufficiently flown, and the output capacitance C1 of the reference phase leg switches Q1, Q2. , C2, the resonance auxiliary circuit 10 can be separated from the switching circuit when the partial resonance current for charging/discharging the C2 can be sufficiently supplied. Therefore, the total loss generated in the DC/RF converter 6 due to the loss generated in the resonance auxiliary circuit 10 is caused. Can be prevented from increasing.

<Thirteenth Embodiment>
In the thirteenth embodiment of the present invention, the auxiliary circuit switch control section 11 shown in FIG. 8 or 9 can achieve impedance matching by the impedance matching device 4 as in the embodiment shown in FIG. The matching state determining means for determining whether or not the first auxiliary circuit switch 10C1 and the second auxiliary circuit switch 10C2 are turned on when the matching state determining means determines that the impedance is not matched. The first and second auxiliary circuit switches 10C1 and 10C2 are turned off when the matching state determining means determines that the impedances are matched. And switch control means for controlling the auxiliary circuit switch. Other configurations are similar to those of the tenth embodiment or the eleventh embodiment.

With the configuration of the present embodiment, the partial resonance current for charging and discharging the output capacitance of the switch of the leg of the control phase is insufficient when the impedance matching by the impedance matching device 4 is not achieved. When it tends to occur, the current flowing from the DC power supply unit 5 through the first auxiliary reactor 10B1 and the first auxiliary circuit switch 10C1 is supplied to the output capacitances C3 and C4 of the control phase leg switches Q3 and Q4. When the partial resonance current for charging and discharging the output capacitance of the switch of the leg of the reference phase is likely to be insufficient, it can be superposed on the partial resonance current for charging and discharging, and the DC power supply unit From the second auxiliary reactor 10B2 and the second auxiliary circuit switch 10C2 to a partial resonance current for charging and discharging the output capacitances C1 and C2 of the switches Q1 and Q2 of the leg of the reference phase. Therefore, during the dead time, the output capacitances C3 and C4 of the leg switches Q3 and Q4 of the control phase and the output capacitance C1 of the leg switches Q1 and Q2 of the reference phase are By completing the charging/discharging of C2, it is possible to reduce the switching loss occurring in each switch.

Further, when the impedance matching is achieved by the impedance matching device 4, the partial resonance current for charging/discharging the output electrostatic capacitances C3, C4 of the switches Q3, Q4 of the leg of the control phase can be sufficiently flown. At this time and when the partial resonance current for charging/discharging the output capacitances C1, C2 of the switches Q1, Q2 of the reference phase leg can be sufficiently flown, the resonance auxiliary circuit 10 can be disconnected from the switching circuit 6A. It is possible to prevent the total loss caused in the DC/RF converter from increasing due to the conduction loss caused in the resonance auxiliary circuit 10.

<Fourteenth Embodiment>
In the present embodiment, as in the embodiment shown in FIG. 3, the auxiliary circuit switch control unit 11 shown in FIG. 8 or 9 is a load detecting the current supplied from the high frequency power generation unit to the load. The current detecting means and the first auxiliary circuit switch 10C1 and the second auxiliary circuit switch 10C2 are turned on when the average value or the effective value of the current detected by the load current detecting means is less than the set value. A first auxiliary circuit switch 10C1 and a second auxiliary circuit switch 10C2 are turned off when the average value or the effective value of the current detected by the load current detection means is equal to or more than a set value. Switch control means for controlling the first and second auxiliary circuit switches. Other configurations are similar to those of the tenth embodiment or the eleventh embodiment.

With the configuration of the present embodiment, a state in which a sufficient partial resonance current can be flowed to complete charging/discharging of the output capacitances C3, C4 of the switches Q3, Q4 of the control phase leg in the dead time period. And whether or not a sufficient partial resonance current can flow when charging and discharging the output capacitances C1 and C2 of the switches Q1 and Q2 of the leg of the reference phase. Can be determined more accurately, and the first and second auxiliary circuit switches can be controlled more accurately.

<Fifteenth Embodiment>
In the present embodiment, the auxiliary circuit switch control unit 11 shown in FIG. 8 or 9 is similar to the embodiment shown in FIG. 4 in that the middle point c and the control phase of the leg of the reference phase of the switching circuit are controlled. Circuit current detection means for detecting a current flowing through the circuit between the middle point d of the leg, and the first auxiliary circuit when the average value or the effective value of the current detected by the circuit current detection means is less than the set value. The first auxiliary circuit switch 10C1 and the second auxiliary circuit switch 10C2 and the second auxiliary circuit switch 10C2 are turned on, and the first auxiliary circuit switch 10C1 and the first auxiliary circuit switch 10C1 The switch control means controls the first auxiliary circuit switch 10C1 and the second auxiliary circuit switch 10C2 so that the second auxiliary circuit switch 10C2 is turned off.

The configuration of the present embodiment is sufficient for charging and discharging the output capacitance of the leg switch of the control phase by the energy stored in the inductor originally present in the circuit in the DC/RF conversion unit 6. It is determined whether or not a partial resonance current can be flowed, and a sufficient partial resonance current can be flowed when charging and discharging the output capacitance of the switch of the leg of the reference phase. It is possible to accurately determine whether or not it is possible to properly control the first and second auxiliary circuit switches.

<Sixteenth Embodiment>
In the present embodiment, the auxiliary circuit switch control section 11 shown in FIG. 8 or 9 determines whether or not impedance matching is achieved by the impedance matching device 4 as in the embodiment shown in FIG. Matching state judging means for judging, load current detecting means for detecting a current supplied to the load from the high-frequency power generating section 3, and matching state judging means for judging that impedances are matched, and load current detecting means When the average value or the effective value of the current detected by is equal to or more than the first set value, and the matching state determination unit determines that the impedance is not matched, the load current detection unit detects the impedance. When the average value or the effective value of the current is equal to or more than the second set value, the first auxiliary circuit switch 10C1 and the second auxiliary circuit switch 10C2 are turned off, and the impedance is matched by the matching state determination means. However, when the average value or the effective value of the current detected by the load current detection means is less than the first set value, and the matching state determination means determines that the impedance is not matched. And the average value or effective value of the current detected by the load current detecting means is less than the second set value, the first auxiliary circuit switch 10C1 and the second auxiliary circuit switch 10C2 are turned on. Switch control means for controlling the first and second auxiliary circuit switches.

According to the configuration of the present embodiment, the impedance matching device does not match the impedance, and the high frequency power generator 3 cannot supply the predetermined traveling wave power to the load. Due to the energy stored in the inductor originally present in the conversion unit 6, it is only necessary to cause a partial resonance current to flow through the charge/discharge circuit configured for each switch, and the output capacitance C3 of the switches Q3, Q4 of the leg of the control phase. , C4 and charging/discharging of the output capacitances C1, C2 of the switches Q1, Q2 of the leg of the reference phase cannot be completed during the dead time, but the impedance is in a matched state. Since the power output from the high-frequency power generator is controlled to suppress the high-frequency power supplied to the load, the energy stored in the inductor originally present in the DC/RF converter is passed through the charge/discharge circuit. Only by supplying a partial resonance current, the output capacitances C3 and C4 of the switches Q3 and Q4 that form the leg of the control phase and the output capacitances C1 and C2 of the switches Q1 and Q2 that form the leg of the reference phase are charged. Even when charging/discharging cannot be completed in the dead time period, the first and second auxiliary circuit switches 10C1 and 10C2 are turned on to charge/discharge each switch of the control phase and each switch of the reference phase. The partial resonance current for charging/discharging can be supplemented.

Further, with the configuration of the present embodiment, impedance matching is achieved and sufficient traveling wave power is output from the high frequency power generator 3, so control is performed without supplementing the partial resonance current through the auxiliary reactor. When the partial resonance current required to complete the charging/discharging of the output capacitance of each switch can be passed through the charging/discharging circuit configured for each switch of the phase leg, and impedance matching However, since the high-frequency power generator outputs a large amount of traveling wave power, it is necessary to complete the charging/discharging of the output capacitances C3, C4 of the switches Q3, Q4 of the leg of the control phase. When the partial resonance current can flow, the first and second auxiliary circuit switches 10C1 and 10C2 can be turned off to disconnect the resonance auxiliary circuit 10 from the switching circuit 6A. According to the present embodiment, compared to the case where it is determined whether to turn on the first and second auxiliary circuit switches only by determining whether the impedances match, it is more detailed. Control can be performed.

<17th Embodiment>
In the present embodiment, the auxiliary circuit switch control section 11 shown in FIG. 8 or 9 determines whether or not impedance matching is achieved by the impedance matching device 4 as in the embodiment shown in FIG. Matching state judging means for judging, circuit current detecting means for detecting a current flowing through a circuit between the middle point c of the leg of the reference phase of the switching circuit 6A and the middle point d of the leg of the control phase, and the matching state judging means. When the impedance matching is determined by the circuit, and the average value or the effective value of the current detected by the circuit current detecting means is equal to or more than the first set value, and the matching state determining means achieves the impedance matching. Although it is determined that it is not, the first auxiliary circuit switch 10C1 and the second auxiliary circuit switch 10C1 and the second auxiliary circuit when the average value or the effective value of the current detected by the circuit current detection means is equal to or more than the second set value. The switch 10C2 is turned off, and the matching state determination unit determines that the impedance is matched, but the average value or the effective value of the current detected by the circuit current detection unit is less than the first set value. And when it is determined that the impedance is not matched by the matching state determination unit and the average value or the effective value of the current detected by the circuit current detection unit is less than the second set value. And a switch control means for controlling the auxiliary circuit switch so that the first auxiliary circuit switch 10C1 and the second auxiliary circuit switch 10C2 are turned on.

According to the configuration of the present embodiment, the first and second auxiliary circuits are based on both the impedance matching state by the impedance matching device and the magnitude of the current flowing through the charge/discharge circuit configured for each switch. Since it is determined whether to turn the power supply switch on or off, the first and second auxiliary circuit switches can be controlled more finely, and the first and second auxiliary circuit switches are undesired. It is possible to prevent an increase in conduction loss that occurs when the control phase leg switch and the reference phase leg switch are turned on.

<Eighteenth embodiment>
In the present embodiment, similar to the embodiment shown in FIG. 7, the current flowing in the circuit between the midpoint c of the leg of the reference phase and the midpoint d of the leg of the control phase of the switching circuit 6A is reflected. Parameter detecting means for detecting a parameter is further provided, and the auxiliary circuit switch control section 11 shown in FIG. 8 or 9 has the parameters detected by the parameter detecting means, the first auxiliary circuit switch 10C1 and the second auxiliary circuit switch 10C1. And a control table storing means for storing an auxiliary circuit switch control table that gives a relationship with the state to be taken by the auxiliary circuit switch 10C2, and searching the control table for the parameter detected by the parameter detecting means. Is used to determine whether the first auxiliary circuit switch 10C1 and the second auxiliary circuit switch 10C2 are in the ON state or the OFF state, and the first auxiliary circuit switch 10C1 and the second auxiliary circuit switch 10C1 And a switch control means for controlling the auxiliary circuit switch 10C2 to be in a determined state.

The first and second auxiliary circuit switch control tables have been experimentally tested to obtain the parameters and the first parameter in order to minimize the switching loss of the control phase leg switch and the reference phase leg switch. Appropriate ones can be created by determining the relationship between the states of the auxiliary circuit switch 10C1 and the second auxiliary circuit switch 10C2 to be taken. With the configuration of the present embodiment, it is possible to accurately control on/off of the first and second auxiliary circuit switches by creating appropriate first and second auxiliary circuit switch control tables. Can be done.

<19th Embodiment>
In the present embodiment, load state determination means for determining the state of impedance when the load side is viewed from the midpoint c of the leg of the reference phase and the midpoint d of the leg of the control phase of the switching circuit 6A is further provided, and FIG. Alternatively, the switch control unit provided in the switch control unit for the auxiliary circuit shown in FIG. 9 looks at the load side from the midpoint of the leg of the reference phase and the midpoint of the leg of the control phase of the switching circuit by the load state determination unit. It is configured to keep the auxiliary circuit switch in the on state when the impedance is determined to be capacitive.

With the configuration of the present embodiment, when the impedance seen from the midpoint of the leg of the switching circuit 6A of the DC/RF conversion unit 6 to the load side becomes capacitive, the first and second auxiliary devices are provided. Since the circuit switch can be turned on to charge and discharge the output capacitance of each switch of the control phase leg and charge and discharge of the output capacitance of the reference phase leg, the high frequency power It is possible to reduce the switching loss that occurs when the impedance seen from the generating unit to the load side becomes capacitive, as compared with the related art.

In the above embodiment, MOSFETs are used as the switching elements that form the high-side switch and the low-side switch of each leg of the switching circuit 6A, but these switches are used when a drive signal equal to or higher than the threshold value is applied. Any switching element that is turned on and turned off when the drive signal becomes less than the threshold value may be used, and other switching such as bipolar transistor and IGBT (insulated gate bipolar transistor) capable of on/off control is possible. Of course, the elements may be used to configure the high-side switch and the low-side switch of each leg.

<Auxiliary circuit switch configuration>
In the first to ninth embodiments, the auxiliary reactor switch 10B is used for connecting the auxiliary reactor 10B to the midpoint of the leg of the control phase of the switch circuit of the DC/RF conversion unit 6 or for disconnecting it from the midpoint. 10C is provided. In addition, in the tenth to nineteenth embodiments, a first auxiliary circuit switch 10C1 is provided for connecting the first auxiliary reactor 10B1 to the midpoint of the leg of the control phase and disconnecting it from the midpoint. A second auxiliary circuit switch 10C2 is provided to connect the second auxiliary reactor 10B2 to the midpoint of the leg of the reference phase or to disconnect the second auxiliary reactor 10B2 from the midpoint. Uses a bidirectional switch that can be turned on and off. Some examples of bidirectional switches suitable for use as auxiliary circuit switches are shown in FIGS. 14 and 15.

The bidirectional switch shown in FIG. 14A is composed of two MOSFETs 21 and 22. In this bidirectional switch, the sources S of the MOSFETs 21 and 22 are commonly connected in order to share the potential of the sources S of the two MOSFETs. In this way, if the source potentials of the MOSFETs 21 and 22 are made common, the drive circuits of both MOSFETs can be made common. When the on-resistance between the drain and the source of the MOSFET is RFET, the on-resistance (resistance when the switch is on) of both switches can be expressed by 2×RFET. When the current flowing between the drain and source when the MOSFET is on is Ion, the conduction loss Ponloss when this bidirectional switch is on is
Ponloss=2×RFET×Ion ² (1)
Given in. The symbols D, S, and G attached to each MOSFET mean a drain, a source, and a gate, respectively.

The bidirectional switch shown in FIG. 14B is a unidirectional switch configured by connecting the anode of the diode 23 to the source of the MOSFET 21 and a unidirectional switch configured by connecting the anode of the diode 24 to the source of the MOSFET 22. Is connected in antiparallel. Assuming that the on-resistance of the MOSFET is RFET, the forward voltage drop of the diode is VDiode, and the energization current when it is on is Ion, the conduction loss Ponloss when this bidirectional switch is on is
Ponloss=Rfet×Ion ² +Vdiode×Ion (2)
Given in. In the dual switch shown in FIG. 14A, it is necessary to turn on two MOSFETs at the same time when performing an on operation. Therefore, in order to achieve high speed, it is necessary to consider the variation of the drive circuit. However, in the bidirectional switch of FIG. 14B, it is not necessary to turn on the two MOSFETs at the same time, and thus it is easy to increase the speed.

In the bidirectional switch shown in FIG. 14C, the emitters E of the two IGBTs 25 and 26 are commonly connected to each other so that the emitter potentials of the two IGBTs are made common. D25 and D26 are parasitic reverse conducting diodes formed between the collector C and the emitter E of the IGBTs 25 and 26, respectively.

In the dual switch shown in FIG. 14C, since there are parasitic reverse conducting diodes D25 and D26, it is not necessary to turn on the two IGBTs at the same time when performing the ON operation, but the parasitic reverse conducting diode D25 is required. Also, the on-voltage of D26 is high. Assuming that the ON voltage of the IGBT is VonIGBT, the forward voltage of the parasitic reverse conduction diode of the IGBT is VIGBTdiode, and the conduction current is Ion, the conduction loss Ponloss when both switches are ON is
Ponloss=(VonIGBT+VIGBTdiode)×Ion (3)
Given in.

The bidirectional switch shown in FIG. 14D has a configuration in which a reverse blocking IGBT 27 having a reverse blocking parasitic diode D27 in series and a reverse blocking IGBT 28 having a reverse blocking parasitic diode D28 in series are connected in antiparallel. , A double switch similar to the double switch of FIG. 14B is configured without using an external diode. Assuming that the ON voltage of the IGBT is VonIGBT, the forward voltage of the parasitic reverse blocking diode of the IGBT is VIGBTdiode, and the energization current is Ion, the conduction loss Ponloss when both switches are ON is also given by the equation (3).

In the bidirectional switch shown in FIG. 15A, an IGBT 30 having a parasitic reverse blocking diode (not shown) is connected in parallel between DC output terminals of a diode bridge rectifying circuit composed of diodes Da to Dd. Is. If the collector-emitter voltage when the IGBT is on is VonIGBT, the forward voltage of the diode is Vdiode, and the conduction current is Ion, the conduction loss Ponloss of both switches shown in FIG.
Ponloss=(VonIGBT+2×Vdiode)×Ion (4)
Given in.

FIG. 15B shows an IGBT 30 having a parasitic reverse conduction diode D30 connected in parallel at both ends of a diode bridge circuit composed of diodes Da to Dd. The conduction loss at ON is given by the above equation (4). To be

If a semiconductor switch is connected between the DC output terminals of the diode bridge rectifier circuit as in the example shown in FIGS. 15A and 15B, one semiconductor switch element is used as a switch element for performing on/off control. A switch having bidirectionality can be configured only by using it.

Although various examples of the configuration of the auxiliary circuit switch have been shown above, the auxiliary circuit switch is not limited to the ones shown in FIGS. 14 and 15 as long as it can be turned on and off and has a small conduction loss. For example, in FIG. 14C, a MOSFET can be used instead of the IGBT. In forming the switch shown in FIG. 14C, when a MOSFET is used instead of the IGBT, in order to reduce the loss, a conduction loss (parasitic diode of the parasitic diode) formed between the drain and the source is generated. In order to reduce the loss (determined by the product of the forward voltage drop and the forward current) as low as possible, it is preferable to use a MOSFET in which the forward voltage drop of the parasitic diode is as low as possible.

Further, in the example shown in FIGS. 15A and 15B, a MOSFET can be used instead of the IGBT. As shown in FIGS. 15A and 15B, when the semiconductor switch is connected in parallel between the DC output terminals of the diode bridge rectifier circuit, the semiconductor switch connected between the DC output terminals of the rectifier circuit is used. Since the current flows only in one direction, the semiconductor switch may be either one in which the current flows in only one direction or one in which the current can flow in both directions.

1 high-frequency power supply device 2 load 3 high-frequency power generation unit 4 impedance matching unit 5 DC power supply unit 6 DC/RF conversion unit 6A switching circuit 6B series resonance circuit 6C transformer 7 low-pass filter 8 power detection unit 9 control unit 10 resonance auxiliary circuit 10A capacitor Voltage dividing circuit 10A1 First capacitor voltage dividing circuit 10A2 Second capacitor voltage dividing circuit 10B Auxiliary reactor 10B1 First auxiliary reactor 10B2 Second auxiliary reactor 10C Auxiliary circuit switch 10C1 First auxiliary circuit switch 10C2 Second Auxiliary circuit switch 11 Auxiliary circuit switch control unit 11A Matching state determination means 11B Switch control means 11C Load current detection means 11D Circuit current detection means 11E Control table storage means Q1 High side switch of reference phase leg Q2 Reference phase Low side switch of leg Q3 High side switch of leg of control phase Q4 Low side switch of leg of control phase C1 to C4 Output capacitance of switches Q1 to Q4 D1 to D4 Feedback diode

Claims (9)

A DC power supply unit that generates a constant DC output and two legs with a high-side switch and a low-side switch connected in series to each other with the connection point of both switches as a middle point are provided, and one and the other of the two legs are connected. A DC/RF conversion unit having a full-bridge type switching circuit having a configuration in which both legs are connected in parallel between the output terminals of the DC power supply unit as a leg for the reference phase and a leg for the control phase; In order to output the high frequency power supplied to the load from the DC/RF conversion unit while providing a dead time which is a period in which the supply of the drive signal to both the high-side switch and the low-side switch forming each leg is stopped, After turning on the high side switch of the phase leg, turn on the low side switch of the control phase leg, and after turning on the low side switch of the reference phase leg, turn on the high side switch of the control phase leg. A high-frequency power generation unit having a control unit that controls a switch that configures the switching circuit so as to alternately perform an operation of turning on, and an impedance matching inserted between the high-frequency power generation unit and a load. And a partial resonance current is caused to flow through the output capacitance of each switch of each leg and the inductor existing in the DC/RF converter to charge and discharge the output capacitance of the switch of each leg. In the high frequency power supply device in which the discharge circuit is configured for each switch,
A capacitor voltage dividing circuit to which the output voltage of the DC power source is applied to both ends, and an auxiliary circuit switch connected between the voltage dividing point of the capacitor voltage dividing circuit and the middle point of the leg of the control phase of the switching circuit. And a supplementary current superposed on a partial resonance current flowing through a charging/discharging circuit configured for each switch of the leg of the control phase, from the DC power supply unit to the capacitor voltage dividing circuit and the auxiliary. A resonance auxiliary circuit that outputs through a reactor and the auxiliary circuit switch,
The auxiliary circuit switch is held in the OFF state when charging/discharging of the output capacitance of the leg switch of the control phase can be completed in the dead time period without superimposing the supplementary current. , The auxiliary circuit switch is turned on when charging/discharging of the output capacitance of the leg switch of the control phase cannot be completed during the dead time without superimposing the supplementary current. An auxiliary circuit switch control unit for controlling on/off of the auxiliary circuit switch ,
Equipped with,
When the auxiliary circuit switch control unit determines that the impedance matching by the impedance matching device is matched, and the matching state determination unit determines that the impedance is not matched. The auxiliary circuit switch is turned on, and the auxiliary circuit switch is controlled to be turned off when the matching state determination means determines that impedance matching is achieved. A high frequency power supply device comprising a switch control means . A DC power supply unit that generates a constant DC output and two legs with a high-side switch and a low-side switch connected in series to each other with the connection point of both switches as a middle point are provided, and one and the other of the two legs are connected. A DC/RF conversion unit having a full-bridge type switching circuit having a configuration in which both legs are connected in parallel between the output terminals of the DC power supply unit as a leg for the reference phase and a leg for the control phase; In order to output the high frequency power supplied to the load from the DC/RF conversion unit while providing a dead time which is a period in which the supply of the drive signal to both the high-side switch and the low-side switch forming each leg is stopped, After turning on the high side switch of the phase leg, turn on the low side switch of the control phase leg, and after turning on the low side switch of the reference phase leg, turn on the high side switch of the control phase leg. A high-frequency power generation unit having a control unit that controls a switch that configures the switching circuit so as to alternately perform an operation of turning on, and an impedance matching inserted between the high-frequency power generation unit and a load. And a partial resonance current is caused to flow through the output capacitance of each switch of each leg and the inductor existing in the DC/RF converter to charge and discharge the output capacitance of the switch of each leg. In the high frequency power supply device in which the discharge circuit is configured for each switch,
A capacitor voltage dividing circuit to which the output voltage of the DC power source is applied to both ends, and an auxiliary circuit switch connected between the voltage dividing point of the capacitor voltage dividing circuit and the middle point of the leg of the control phase of the switching circuit. And a supplementary current superposed on a partial resonance current flowing through a charging/discharging circuit configured for each switch of the leg of the control phase, from the DC power supply unit to the capacitor voltage dividing circuit and the auxiliary. A resonance auxiliary circuit that outputs through a reactor and the auxiliary circuit switch,
The auxiliary circuit switch is held in the OFF state when charging/discharging of the output capacitance of the leg switch of the control phase can be completed in the dead time period without superimposing the supplementary current. , The auxiliary circuit switch is turned on when charging/discharging of the output capacitance of the leg switch of the control phase cannot be completed during the dead time without superimposing the supplementary current. An auxiliary circuit switch control unit for controlling on/off of the auxiliary circuit switch,
Equipped with,
The auxiliary circuit switch control unit includes a matching state determination unit that determines whether or not impedance matching is achieved by the impedance matching unit, and a load current detection unit that detects a current supplied to the load from the high frequency power generation unit. Means and the matching state determination means determines that impedance matching is achieved, and the average value or effective value of the current detected by the load current detection means is equal to or greater than a first set value, and For the auxiliary circuit, when the matching state determination unit determines that the impedance is not matched, but the average value or the effective value of the current detected by the load current detection unit is equal to or greater than the second set value. The switch is turned off and the matching state determination means determines that impedance matching is achieved, but the average value or effective value of the current detected by the load current detection means is less than the first set value. And when the matching state determination unit determines that the impedance is not matched, and the average value or the effective value of the current detected by the load current detection unit is less than the second set value. And a switch control means for controlling the auxiliary circuit switch so as to turn on the auxiliary circuit switch . A DC power supply unit that generates a constant DC output and two legs with a high-side switch and a low-side switch connected in series to each other with the connection point of both switches as a middle point are provided, and one and the other of the two legs are connected. A DC/RF conversion unit having a full-bridge type switching circuit having a configuration in which both legs are connected in parallel between the output terminals of the DC power supply unit as a leg for the reference phase and a leg for the control phase; In order to output the high frequency power supplied to the load from the DC/RF conversion unit while providing a dead time which is a period in which the supply of the drive signal to both the high-side switch and the low-side switch forming each leg is stopped, After turning on the high side switch of the phase leg, turn on the low side switch of the control phase leg, and after turning on the low side switch of the reference phase leg, turn on the high side switch of the control phase leg. A high-frequency power generation unit having a control unit that controls a switch that configures the switching circuit so as to alternately perform an operation of turning on, and an impedance matching inserted between the high-frequency power generation unit and a load. And a partial resonance current is caused to flow through the output capacitance of each switch of each leg and the inductor existing in the DC/RF converter to charge and discharge the output capacitance of the switch of each leg. In the high frequency power supply device in which the discharge circuit is configured for each switch,
A capacitor voltage dividing circuit to which the output voltage of the DC power source is applied to both ends, and an auxiliary circuit switch connected between the voltage dividing point of the capacitor voltage dividing circuit and the middle point of the leg of the control phase of the switching circuit. And a supplementary current superposed on a partial resonance current flowing through a charging/discharging circuit configured for each switch of the leg of the control phase, from the DC power supply unit to the capacitor voltage dividing circuit and the auxiliary. A resonance auxiliary circuit that outputs through a reactor and the auxiliary circuit switch,
The auxiliary circuit switch is held in the OFF state when charging/discharging of the output capacitance of the leg switch of the control phase can be completed in the dead time period without superimposing the supplementary current. , The auxiliary circuit switch is turned on when charging/discharging of the output capacitance of the leg switch of the control phase cannot be completed during the dead time without superimposing the supplementary current. An auxiliary circuit switch control unit for controlling on/off of the auxiliary circuit switch,
Equipped with,
The auxiliary circuit switch control unit includes a matching state determination unit that determines whether or not impedance matching is achieved by the impedance matching unit, and a middle point of a leg of a reference phase and a leg of a control phase of the switching circuit. Circuit current detecting means for detecting the current flowing through the circuit between the point and the point, the matching state determining means determines that the impedance is matched, and the average value of the current detected by the circuit current detecting means or When the effective value is equal to or greater than the first set value, and the impedance is not matched by the matching state determination means, the average value or the effective value of the current detected by the circuit current detection means. Is above the second set value, the auxiliary circuit switch is turned off, and the matching state determination means determines that impedance matching is achieved, but the circuit current detection means detects the impedance. When the average value or the effective value of the current is less than the first set value, and when the matching state determination means determines that the impedance is not matched, and the average current detected by the circuit current detection means And a switch control means for controlling the auxiliary circuit switch so that the auxiliary circuit switch is turned on when the value or the effective value is less than the second set value. Power supply. A DC power supply unit that generates a constant DC output and two legs with a high-side switch and a low-side switch connected in series to each other with the connection point of both switches as a middle point are provided, and one and the other of the two legs are connected. A DC/RF conversion unit having a full-bridge type switching circuit having a configuration in which both legs are connected in parallel between the output terminals of the DC power supply unit as a leg for the reference phase and a leg for the control phase; In order to output the high frequency power supplied to the load from the DC/RF conversion unit while providing a dead time which is a period in which the supply of the drive signal to both the high-side switch and the low-side switch forming each leg is stopped, After turning on the high side switch of the phase leg, turn on the low side switch of the control phase leg, and after turning on the low side switch of the reference phase leg, turn on the high side switch of the control phase leg. A high-frequency power generation unit having a control unit that controls a switch that configures the switching circuit so as to alternately perform an operation of turning on, and an impedance matching inserted between the high-frequency power generation unit and a load. And a partial resonance current is caused to flow through the output capacitance of each switch of each leg and the inductor existing in the DC/RF converter to charge and discharge the output capacitance of the switch of each leg. In the high frequency power supply device in which the discharge circuit is configured for each switch,
For a first auxiliary circuit between a capacitor voltage dividing circuit to which the output voltage of the DC power supply unit is applied, and a voltage dividing point of the capacitor voltage dividing circuit and the middle point of the leg of the control phase of the switching circuit. A first auxiliary reactor connected through a switch, and a second auxiliary circuit switch connected between the voltage dividing point of the capacitor voltage dividing circuit and the midpoint of the leg of the reference phase of the switching circuit. And a supplementary current superposed on a partial resonance current flowing through a charging/discharging circuit configured for each switch of the leg of the control phase, from the DC power supply unit to the capacitor voltage dividing circuit and the first auxiliary reactor. From the DC power supply unit, a supplementary current that is output through the auxiliary reactor and the first auxiliary circuit switch, and that is superimposed on the partial resonance current flowing through the charge/discharge circuit configured for each switch of the leg of the reference phase. A resonance auxiliary circuit that outputs through a capacitor voltage dividing circuit, a second auxiliary reactor, and a second auxiliary circuit switch;
Dead time for charging/discharging the output capacitance of the switch forming the leg of the control phase without superposing the supplementary current on the partial resonance current flowing through the charge/discharge circuit formed for each switch of the control phase leg. The first auxiliary circuit switch is turned off when it can be completed in the period of, and the supplementary current is superimposed on the partial resonance current flowing through the charge/discharge circuit configured for each switch of the leg of the control phase. Otherwise, the first auxiliary circuit switch is turned on when charging/discharging of the output capacitance of the switch forming the leg of the control phase cannot be completed in the dead time period. Each switch that controls the ON/OFF of the auxiliary circuit switch and configures the leg of the reference phase without superposing the supplementary current on the partial resonance current flowing through the charge/discharge circuit configured for each switch of the leg of the reference phase. The second auxiliary circuit switch is turned off when the charging/discharging of the output capacitance can be completed during the dead time, and the charging/discharging configured for each switch of the leg of the reference phase. For the second auxiliary circuit when charging/discharging of the output capacitance of each switch forming the leg of the reference phase cannot be completed during the dead time unless the supplemental current is superimposed on the partial resonance current flowing through the circuit. An auxiliary circuit switch control unit for controlling on/off of the second auxiliary circuit switch so that the switch is turned on;
Equipped with,
When the auxiliary circuit switch control unit determines that the impedance is not matched by the impedance matching device, and the matching state determination unit determines that the impedance is not matched. The first and second auxiliary circuit switches are turned on, and the first and second auxiliary circuit switches are turned off when the matching state determination means determines that impedance matching is achieved. And a switch control means for controlling the first and second auxiliary circuit switches . A DC power supply unit that generates a constant DC output and two legs with a high-side switch and a low-side switch connected in series to each other with the connection point of both switches as a middle point are provided, and one and the other of the two legs are connected. A DC/RF conversion unit having a full-bridge type switching circuit having a configuration in which both legs are connected in parallel between the output terminals of the DC power supply unit as a leg for the reference phase and a leg for the control phase; In order to output the high frequency power supplied to the load from the DC/RF conversion unit while providing a dead time which is a period in which the supply of the drive signal to both the high-side switch and the low-side switch forming each leg is stopped, After turning on the high side switch of the phase leg, turn on the low side switch of the control phase leg, and after turning on the low side switch of the reference phase leg, turn on the high side switch of the control phase leg. A high-frequency power generation unit having a control unit that controls a switch that configures the switching circuit so as to alternately perform an operation of turning on, and an impedance matching inserted between the high-frequency power generation unit and a load. And a discharge device for charging and discharging the output capacitance of each leg switch by flowing a partial resonance current through the output capacitance of each leg switch and the inductor existing in the DC/RF converter. In a high frequency power supply where the circuit is configured for each switch,
A first capacitor voltage dividing circuit, to which the output voltage of the DC power source unit is applied, and a voltage dividing point of the first capacitor voltage dividing circuit and a middle point of the leg of the control phase of the switching circuit. A first auxiliary reactor connected through one auxiliary circuit switch, a second capacitor voltage dividing circuit to which the output voltage of the DC power supply unit is applied to both ends, and a voltage dividing point of the second capacitor voltage dividing circuit. And a second auxiliary reactor connected through a second auxiliary circuit switch between the switching circuit and the midpoint of the leg of the reference phase of the switching circuit, and configured for each switch of the leg of the control phase. A supplementary current superimposed on the partial resonance current flowing through the charging/discharging circuit is output from the DC power supply unit through the first capacitor voltage dividing circuit, the first auxiliary reactor, and the first auxiliary circuit switch, and A replenishment current superimposed on a partial resonance current flowing through a charging/discharging circuit configured for each switch of the leg of the reference phase is supplied from the DC power supply unit to the second capacitor voltage dividing circuit, the second auxiliary reactor, and the second auxiliary reactor. A resonance auxiliary circuit that outputs through an auxiliary circuit switch,
The charge/discharge of the output capacitance of each switch constituting the leg of the control phase is dead without superimposing the supplementary current on the partial resonance current flowing through the charge/discharge circuit configured for each switch of the leg of the control phase. When it can be completed during the time period, the first auxiliary circuit switch is turned off, and the supplemental current is supplied to the partial resonance current flowing through the charge/discharge circuit configured for each switch of the leg of the control phase. The first auxiliary circuit switch is turned on when charging/discharging of the output capacitance of each switch constituting the leg of the control phase cannot be completed during the dead time unless superposed. The ON/OFF of the auxiliary circuit switch No. 1 is controlled, and the leg of the reference phase is configured without superposing the supplementary current on the partial resonance current flowing through the charge/discharge circuit configured for each switch of the leg of the reference phase. The second auxiliary circuit switch is turned off when charging/discharging of the output capacitance of each switch can be completed during the dead time, and each switch of the leg of the reference phase is configured. The second auxiliary when the charging/discharging of the output capacitance of each switch forming the leg of the reference phase cannot be completed during the dead time unless the supplemental current is superposed on the partial resonance current flowing through the charging/discharging circuit. An auxiliary circuit switch control unit for controlling on/off of the second auxiliary circuit switch so as to turn on the circuit switch ,
Equipped with,
When the auxiliary circuit switch control unit determines that the impedance is not matched by the impedance matching device, and the matching state determination unit determines that the impedance is not matched. The first and second auxiliary circuit switches are turned on, and the first and second auxiliary circuit switches are turned off when the matching state determination means determines that impedance matching is achieved. And a switch control means for controlling the first and second auxiliary circuit switches . A DC power supply unit that generates a constant DC output and two legs with a high-side switch and a low-side switch connected in series to each other with the connection point of both switches as a middle point are provided, and one and the other of the two legs are connected. A DC/RF conversion unit having a full-bridge type switching circuit having a configuration in which both legs are connected in parallel between the output terminals of the DC power supply unit as a leg for the reference phase and a leg for the control phase; In order to output the high frequency power supplied to the load from the DC/RF conversion unit while providing a dead time which is a period in which the supply of the drive signal to both the high-side switch and the low-side switch forming each leg is stopped, After turning on the high side switch of the phase leg, turn on the low side switch of the control phase leg, and after turning on the low side switch of the reference phase leg, turn on the high side switch of the control phase leg. A high-frequency power generation unit having a control unit that controls a switch that configures the switching circuit so as to alternately perform an operation of turning on, and an impedance matching inserted between the high-frequency power generation unit and a load. And a partial resonance current is caused to flow through the output capacitance of each switch of each leg and the inductor existing in the DC/RF converter to charge and discharge the output capacitance of the switch of each leg. In the high frequency power supply device in which the discharge circuit is configured for each switch,
For a first auxiliary circuit between a capacitor voltage dividing circuit to which the output voltage of the DC power supply unit is applied, and a voltage dividing point of the capacitor voltage dividing circuit and the middle point of the leg of the control phase of the switching circuit. A first auxiliary reactor connected through a switch, and a second auxiliary circuit switch connected between the voltage dividing point of the capacitor voltage dividing circuit and the midpoint of the leg of the reference phase of the switching circuit. And a supplementary current superposed on a partial resonance current flowing through a charging/discharging circuit configured for each switch of the leg of the control phase, from the DC power supply unit to the capacitor voltage dividing circuit and the first auxiliary reactor. From the DC power supply unit, a supplementary current that is output through the auxiliary reactor and the first auxiliary circuit switch, and that is superimposed on the partial resonance current flowing through the charge/discharge circuit configured for each switch of the leg of the reference phase. A resonance auxiliary circuit that outputs through a capacitor voltage dividing circuit, a second auxiliary reactor, and a second auxiliary circuit switch;
Dead time for charging/discharging the output capacitance of the switch forming the leg of the control phase without superposing the supplementary current on the partial resonance current flowing through the charge/discharge circuit formed for each switch of the control phase leg. The first auxiliary circuit switch is turned off when it can be completed in the period of, and the supplementary current is superimposed on the partial resonance current flowing through the charge/discharge circuit configured for each switch of the leg of the control phase. Otherwise, the first auxiliary circuit switch is turned on when charging/discharging of the output capacitance of the switch forming the leg of the control phase cannot be completed in the dead time period. Each switch that controls the ON/OFF of the auxiliary circuit switch and configures the leg of the reference phase without superposing the supplementary current on the partial resonance current flowing through the charge/discharge circuit configured for each switch of the leg of the reference phase. The second auxiliary circuit switch is turned off when the charging/discharging of the output capacitance can be completed during the dead time, and the charging/discharging configured for each switch of the leg of the reference phase. For the second auxiliary circuit when charging/discharging of the output capacitance of each switch forming the leg of the reference phase cannot be completed during the dead time unless the supplemental current is superimposed on the partial resonance current flowing through the circuit. An auxiliary circuit switch control unit for controlling on/off of the second auxiliary circuit switch so that the switch is turned on;
Equipped with,
The auxiliary circuit switch control unit includes a matching state determination unit that determines whether or not impedance matching is achieved by the impedance matching unit, and a load current detection unit that detects a current supplied to the load from the high frequency power generation unit. Means and the matching state determination means determines that impedance matching is achieved, and the average value or effective value of the current detected by the load current detection means is equal to or greater than a first set value, and It is determined that the impedance is not matched by the matching state determination means, but when the average value or the effective value of the current detected by the load current detection means is the second set value or more, the first The auxiliary circuit switch and the second auxiliary circuit switch are turned off, and the matching state determination means determines that impedance matching has been achieved. However, the average value of the current detected by the load current detection means. Alternatively, when the effective value is less than the first set value, and when the matching state determination unit determines that impedance is not matched, and the average value or the effective value of the current detected by the load current detection unit. A switch for controlling the first and second auxiliary circuit switches so as to turn on the first auxiliary circuit switch and the second auxiliary circuit switch when is less than the second set value. A high-frequency power supply device comprising: a control unit . A DC power supply unit that generates a constant DC output and two legs with a high-side switch and a low-side switch connected in series to each other with the connection point of both switches as a middle point are provided, and one and the other of the two legs are connected. A DC/RF conversion unit having a full-bridge type switching circuit having a configuration in which both legs are connected in parallel between the output terminals of the DC power supply unit as a leg for the reference phase and a leg for the control phase; In order to output the high frequency power supplied to the load from the DC/RF conversion unit while providing a dead time which is a period in which the supply of the drive signal to both the high-side switch and the low-side switch forming each leg is stopped, After turning on the high side switch of the phase leg, turn on the low side switch of the control phase leg, and after turning on the low side switch of the reference phase leg, turn on the high side switch of the control phase leg. A high-frequency power generation unit having a control unit that controls a switch that configures the switching circuit so as to alternately perform an operation of turning on, and an impedance matching inserted between the high-frequency power generation unit and a load. And a discharge device for charging and discharging the output capacitance of each leg switch by flowing a partial resonance current through the output capacitance of each leg switch and the inductor existing in the DC/RF converter. In a high frequency power supply where the circuit is configured for each switch,
A first capacitor voltage dividing circuit, to which the output voltage of the DC power source unit is applied, and a voltage dividing point of the first capacitor voltage dividing circuit and a middle point of the leg of the control phase of the switching circuit. A first auxiliary reactor connected through one auxiliary circuit switch, a second capacitor voltage dividing circuit to which the output voltage of the DC power supply unit is applied to both ends, and a voltage dividing point of the second capacitor voltage dividing circuit. And a second auxiliary reactor connected through a second auxiliary circuit switch between the switching circuit and the midpoint of the leg of the reference phase of the switching circuit, and configured for each switch of the leg of the control phase. A supplementary current superimposed on the partial resonance current flowing through the charging/discharging circuit is output from the DC power supply unit through the first capacitor voltage dividing circuit, the first auxiliary reactor, and the first auxiliary circuit switch, and A replenishment current superimposed on a partial resonance current flowing through a charging/discharging circuit configured for each switch of the leg of the reference phase is supplied from the DC power supply unit to the second capacitor voltage dividing circuit, the second auxiliary reactor, and the second auxiliary reactor. A resonance auxiliary circuit that outputs through an auxiliary circuit switch,
The charge/discharge of the output capacitance of each switch constituting the leg of the control phase is dead without superimposing the supplementary current on the partial resonance current flowing through the charge/discharge circuit configured for each switch of the leg of the control phase. When it can be completed during the time period, the first auxiliary circuit switch is turned off, and the supplemental current is supplied to the partial resonance current flowing through the charge/discharge circuit configured for each switch of the leg of the control phase. The first auxiliary circuit switch is turned on when charging/discharging of the output capacitance of each switch constituting the leg of the control phase cannot be completed during the dead time unless superposed. The ON/OFF of the auxiliary circuit switch No. 1 is controlled, and the leg of the reference phase is configured without superposing the supplementary current on the partial resonance current flowing through the charge/discharge circuit configured for each switch of the leg of the reference phase. The second auxiliary circuit switch is turned off when charging/discharging of the output capacitance of each switch can be completed during the dead time, and each switch of the leg of the reference phase is configured. The second auxiliary when the charging/discharging of the output capacitance of each switch forming the leg of the reference phase cannot be completed during the dead time unless the supplemental current is superposed on the partial resonance current flowing through the charging/discharging circuit. An auxiliary circuit switch control unit for controlling on/off of the second auxiliary circuit switch so as to turn on the circuit switch,
Equipped with,
The auxiliary circuit switch control unit includes a matching state determination unit that determines whether or not impedance matching is achieved by the impedance matching unit, and a load current detection unit that detects a current supplied to the load from the high frequency power generation unit. Means and the matching state determination means determines that impedance matching is achieved, and the average value or effective value of the current detected by the load current detection means is equal to or greater than a first set value, and It is determined that the impedance is not matched by the matching state determination means, but when the average value or the effective value of the current detected by the load current detection means is the second set value or more, the first The auxiliary circuit switch and the second auxiliary circuit switch are turned off, and the matching state determination means determines that impedance matching has been achieved. However, the average value of the current detected by the load current detection means. Alternatively, when the effective value is less than the first set value, and when the matching state determination unit determines that impedance is not matched, and the average value or the effective value of the current detected by the load current detection unit. A switch for controlling the first and second auxiliary circuit switches so as to turn on the first auxiliary circuit switch and the second auxiliary circuit switch when is less than the second set value. A high-frequency power supply device comprising a control means. A DC power supply unit that generates a constant DC output and two legs with a high-side switch and a low-side switch connected in series to each other with the connection point of both switches as a middle point are provided, and one and the other of the two legs are connected. A DC/RF conversion unit having a full-bridge type switching circuit having a configuration in which both legs are connected in parallel between the output terminals of the DC power supply unit as a leg for the reference phase and a leg for the control phase; In order to output the high frequency power supplied to the load from the DC/RF conversion unit while providing a dead time which is a period in which the supply of the drive signal to both the high-side switch and the low-side switch forming each leg is stopped, After turning on the high side switch of the phase leg, turn on the low side switch of the control phase leg, and after turning on the low side switch of the reference phase leg, turn on the high side switch of the control phase leg. A high-frequency power generation unit having a control unit that controls a switch that configures the switching circuit so as to alternately perform an operation of turning on, and an impedance matching inserted between the high-frequency power generation unit and a load. And a partial resonance current is caused to flow through the output capacitance of each switch of each leg and the inductor existing in the DC/RF converter to charge and discharge the output capacitance of the switch of each leg. In the high frequency power supply device in which the discharge circuit is configured for each switch,
For a first auxiliary circuit between a capacitor voltage dividing circuit to which the output voltage of the DC power supply unit is applied, and a voltage dividing point of the capacitor voltage dividing circuit and the middle point of the leg of the control phase of the switching circuit. A first auxiliary reactor connected through a switch, and a second auxiliary circuit switch connected between the voltage dividing point of the capacitor voltage dividing circuit and the midpoint of the leg of the reference phase of the switching circuit. And a supplementary current superposed on a partial resonance current flowing through a charging/discharging circuit configured for each switch of the leg of the control phase, from the DC power supply unit to the capacitor voltage dividing circuit and the first auxiliary reactor. From the DC power supply unit, a supplementary current that is output through the auxiliary reactor and the first auxiliary circuit switch, and that is superimposed on the partial resonance current flowing through the charge/discharge circuit configured for each switch of the leg of the reference phase. A resonance auxiliary circuit that outputs through a capacitor voltage dividing circuit, a second auxiliary reactor, and a second auxiliary circuit switch;
Dead time for charging/discharging the output capacitance of the switch forming the leg of the control phase without superposing the supplementary current on the partial resonance current flowing through the charge/discharge circuit formed for each switch of the control phase leg. The first auxiliary circuit switch is turned off when it can be completed in the period of, and the supplementary current is superimposed on the partial resonance current flowing through the charge/discharge circuit configured for each switch of the leg of the control phase. Otherwise, the first auxiliary circuit switch is turned on when charging/discharging of the output capacitance of the switch forming the leg of the control phase cannot be completed in the dead time period. Each switch that controls the ON/OFF of the auxiliary circuit switch and configures the leg of the reference phase without superposing the supplementary current on the partial resonance current flowing through the charge/discharge circuit configured for each switch of the leg of the reference phase. The second auxiliary circuit switch is turned off when the charging/discharging of the output capacitance can be completed during the dead time, and the charging/discharging configured for each switch of the leg of the reference phase. For the second auxiliary circuit when charging/discharging of the output capacitance of each switch forming the leg of the reference phase cannot be completed during the dead time unless the supplemental current is superimposed on the partial resonance current flowing through the circuit. An auxiliary circuit switch control unit for controlling on/off of the second auxiliary circuit switch so that the switch is turned on;
Equipped with,
The auxiliary circuit switch control unit includes a matching state determination unit that determines whether or not impedance matching is achieved by the impedance matching unit, and a middle point of a leg of a reference phase and a leg of a control phase of the switching circuit. Circuit current detecting means for detecting the current flowing through the circuit between the point and the point, and the average value of the current detected by the circuit current detecting means, which is determined by the matching state determining means impedance matching When the effective value is equal to or higher than the first set value, and the impedance is not determined to be matched by the matching state determination means, the average value or the effective value of the current detected by the circuit current detection means. Is greater than or equal to the second set value, the first auxiliary circuit switch and the second auxiliary circuit switch are turned off, and the matching state determination means determines that impedance matching is achieved. However, when the average value or the effective value of the current detected by the circuit current detection means is less than the first set value, and it is determined that the impedance is not matched by the matching state determination means, and When the average value or the effective value of the current detected by the circuit current detection means is less than the second set value, the first auxiliary circuit switch and the second auxiliary circuit switch are turned on. A high-frequency power supply device comprising: a switch control unit that controls the auxiliary circuit switch . A DC power supply unit that generates a constant DC output and two legs with a high-side switch and a low-side switch connected in series to each other with the connection point of both switches as a middle point are provided, and one and the other of the two legs are connected. A DC/RF conversion unit having a full-bridge type switching circuit having a configuration in which both legs are connected in parallel between the output terminals of the DC power supply unit as a leg for the reference phase and a leg for the control phase; In order to output the high frequency power supplied to the load from the DC/RF conversion unit while providing a dead time which is a period in which the supply of the drive signal to both the high-side switch and the low-side switch forming each leg is stopped, After turning on the high side switch of the phase leg, turn on the low side switch of the control phase leg, and after turning on the low side switch of the reference phase leg, turn on the high side switch of the control phase leg. A high-frequency power generation unit having a control unit that controls a switch that configures the switching circuit so as to alternately perform an operation of turning on, and an impedance matching inserted between the high-frequency power generation unit and a load. And a discharge device for charging and discharging the output capacitance of each leg switch by flowing a partial resonance current through the output capacitance of each leg switch and the inductor existing in the DC/RF converter. In a high frequency power supply where the circuit is configured for each switch,
A first capacitor voltage dividing circuit, to which the output voltage of the DC power source unit is applied, and a voltage dividing point of the first capacitor voltage dividing circuit and a middle point of the leg of the control phase of the switching circuit. A first auxiliary reactor connected through one auxiliary circuit switch, a second capacitor voltage dividing circuit to which the output voltage of the DC power supply unit is applied to both ends, and a voltage dividing point of the second capacitor voltage dividing circuit. And a second auxiliary reactor connected through a second auxiliary circuit switch between the switching circuit and the midpoint of the leg of the reference phase of the switching circuit, and configured for each switch of the leg of the control phase. A supplementary current superimposed on the partial resonance current flowing through the charging/discharging circuit is output from the DC power supply unit through the first capacitor voltage dividing circuit, the first auxiliary reactor, and the first auxiliary circuit switch, and A replenishment current superimposed on a partial resonance current flowing through a charging/discharging circuit configured for each switch of the leg of the reference phase is supplied from the DC power supply unit to the second capacitor voltage dividing circuit, the second auxiliary reactor, and the second auxiliary reactor. A resonance auxiliary circuit that outputs through an auxiliary circuit switch,
The charge/discharge of the output capacitance of each switch constituting the leg of the control phase is dead without superimposing the supplementary current on the partial resonance current flowing through the charge/discharge circuit configured for each switch of the leg of the control phase. When it can be completed during the time period, the first auxiliary circuit switch is turned off, and the supplemental current is supplied to the partial resonance current flowing through the charge/discharge circuit configured for each switch of the leg of the control phase. The first auxiliary circuit switch is turned on when charging/discharging of the output capacitance of each switch constituting the leg of the control phase cannot be completed during the dead time unless superposed. The ON/OFF of the auxiliary circuit switch No. 1 is controlled, and the leg of the reference phase is configured without superposing the supplementary current on the partial resonance current flowing through the charge/discharge circuit configured for each switch of the leg of the reference phase. The second auxiliary circuit switch is turned off when charging/discharging of the output capacitance of each switch can be completed during the dead time, and each switch of the leg of the reference phase is configured. The second auxiliary when the charging/discharging of the output capacitance of each switch forming the leg of the reference phase cannot be completed during the dead time unless the supplemental current is superposed on the partial resonance current flowing through the charging/discharging circuit. An auxiliary circuit switch control unit for controlling on/off of the second auxiliary circuit switch so as to turn on the circuit switch,
Equipped with,
The auxiliary circuit switch control unit includes a matching state determination unit that determines whether or not impedance matching is achieved by the impedance matching unit, and a middle point of a leg of a reference phase and a leg of a control phase of the switching circuit. Circuit current detecting means for detecting the current flowing through the circuit between the point and the point, and the average value of the current detected by the circuit current detecting means, which is determined by the matching state determining means impedance matching When the effective value is equal to or higher than the first set value, and the impedance is not determined to be matched by the matching state determination means, the average value or the effective value of the current detected by the circuit current detection means. Is greater than or equal to the second set value, the first auxiliary circuit switch and the second auxiliary circuit switch are turned off, and the matching state determination means determines that impedance matching is achieved. However, when the average value or the effective value of the current detected by the circuit current detection means is less than the first set value, and it is determined that the impedance is not matched by the matching state determination means, and When the average value or the effective value of the current detected by the circuit current detection means is less than the second set value, the first auxiliary circuit switch and the second auxiliary circuit switch are turned on. A high-frequency power supply device comprising: a switch control unit that controls the auxiliary circuit switch .

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