JP2019161853A - Converter device - Google Patents

Abstract

To provide a one-stage converter device for avoiding an excessive current from occurring when output is short-circuited while enabling control on an output voltage without changing switching frequency.SOLUTION: A converter device includes: a series rectifier element part 8 having a transformer 2 having windings 2a, 2b, a switching circuit part 7, and diodes 8a, 8b whose connection points are connected to a second AC terminal part 6b; a series circuit part 10 which is constituted by a switch 10a and a capacitor 10b, and whose one end is connected to the current output end of the series rectifier element part 8 and other end is connected to a second AC terminal part 6a; a series circuit part 11 which is constituted by a switch 11a and a capacitor 11b, and whose one end is connected to the second AC terminal part 6a and other end is connected to a current input end of the series rectifier element part 8; and a control part 13 in which an input DC voltage Vin is converted to an output DC voltage Vout to be outputted by performing switching control on the switching circuit part 7 and the switches 10a, 10b.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a converter device that converts an input DC voltage into an output DC voltage and outputs the same.

  As this type of converter device, a converter device (current resonance type DC-DC converter) disclosed in Non-Patent Document 1 below is known. In this converter device, normally, an input voltage (input voltage) is equivalently connected in series with this converter device that functions as an LC resonance circuit and a load (a load that supplies a voltage converted in this converter device). It is comprised so that it may become a state. In this converter device, the impedance of the converter device functioning as an LC resonance circuit can be changed by changing the operating frequency (switching frequency). For this reason, in this converter device, the voltage (output voltage) supplied to the load is stabilized by changing the operating frequency.

  However, the configuration that changes the operating frequency and stabilizes the output voltage as in this converter device, when the operating frequency must be increased depending on the operating conditions, switching loss and loss in magnetic parts such as transformers The problem arises that increases. This converter device also has a problem that it is difficult to control the output voltage at the time of an overcurrent, and a problem that an excessive current flows when the output is short-circuited to make a stable operation difficult.

  This problem can be improved by adopting the configuration of the converter device (current resonance type DC-DC converter) disclosed in Non-Patent Document 2 below. Specifically, this converter device is configured as a two-stage converter composed of a step-down circuit (Buck Converter) and a current resonance converter that operates at a fixed frequency (a constant switching frequency), and the switching operation of the step-down circuit. By controlling (PWM control), the DC voltage supplied from the step-down circuit to the current resonance converter can be changed to a low voltage. Therefore, in this converter device, the switching loss in the current resonance converter and the loss in the magnetic component are avoided, and the load is supplied to the load even in an overload state (a state in which an excessive current flows) including the output short-circuit state. The voltage (output voltage) can be stabilized.

ROBERT L. STEIGERWALD, “A Comparison of Half-Bridge Resonant Converter Topologies”, IEEE TRANSACTIONS ON POWER ELECTRONICS, VOL. 3, NO. 2, APRIL 1988 Shi-Yi Lin and three others, “Implementation and Study of Constant-Frequency LLC Resonant Converter”, [online], First Online: 28 February 2013, [Search February 15, 2018], Internet <URL: https: //link.springer.com/chapter/10.1007/978-1-4614-6747-2_75>

  However, the converter device disclosed in Non-Patent Document 2 has the following problems to be solved. That is, in the step-down circuit included in the converter device, the main switch cannot achieve soft switching. Therefore, this converter device has a problem to be solved that a large switching loss occurs.

  The present invention has been made to solve such a problem, and provides a one-stage type converter device that can control the output voltage without changing the switching frequency and can avoid the occurrence of an excessive current when the output is short-circuited. The main purpose is to provide.

  In order to achieve the above object, a converter device according to the present invention includes a transformer in which a first winding and a second winding are formed, a pair of first DC terminal portions, and a pair of first connection lines. A pair of first AC terminals connected to the first winding, a pair of second DC terminals, and a pair of second AC terminals connected to the second winding via a pair of second connection lines And a pair of first DC terminal portions and a pair of first AC terminal portions, and converts an input DC voltage input to the pair of first DC terminal portions into an AC voltage. And the switching circuit portion that outputs to the pair of first AC terminal portions and the second AC terminal portion that is connected in series with the forward direction aligned and whose connection point is one of the pair of second AC terminal portions. The first rectifying element and the second rectifying element connected to each other, and the current output end is the first One of the pair of second DC terminal portions is connected to the second DC terminal portion of the pair of second DC terminal portions via a power line, and a current input end portion is connected to the second power terminal portion of the pair of second DC terminal portions via the second power line. A series rectifying element connected to the other second DC terminal, an inductor inserted and connected to at least one of the first power line and the second power line, a first switch connected in series, and The first capacitor is configured such that one end is connected to the current output end of the series rectifying element portion and the other end is the other second AC of the pair of second AC terminal portions. A first series circuit portion connected to the terminal portion, a second switch and a second capacitor connected in series, one end portion being connected to the other second AC terminal portion and the other end In front of the series rectifier element A second series circuit portion connected to a current input end, an LC resonance circuit inserted and connected to at least one of the pair of first connection lines and the pair of second connection lines, the switching circuit portion, A control unit that performs switching control on the first switch and the second switch to convert the input DC voltage into an output DC voltage and output the output DC voltage between the pair of second DC terminal units.

  In the converter device, the control unit executes the switching control to generate an induced voltage at which the other second AC terminal unit has a high potential with respect to the one second AC terminal unit. Energy is generated in the wire, and the first switch is turned off and the second switch is turned on, so that energy is accumulated in the second capacitor based on the induced voltage and accumulated in the inductor. A first operation for outputting the output DC voltage by releasing the generated energy, and an induced voltage at which the other second AC terminal portion has a high potential with respect to the one second AC terminal portion. The second capacitor is generated based on the induced voltage by causing the first switch and the second switch to be in an ON state while being generated in the winding. A second operation of storing energy and discharging the energy stored in the first capacitor to output the output DC voltage and storing energy in the inductor; On the other hand, by causing the second winding to generate an induced voltage at which the one second AC terminal portion has a high potential, the first switch is turned on, and the second switch is turned off. A third operation for storing energy in the first capacitor based on the induced voltage and outputting the output DC voltage by releasing energy stored in the inductor, and the other second AC terminal. In addition to causing the second winding to generate an induced voltage at which the one second AC terminal portion has a high potential relative to the portion, the first winding By turning on the switch and the second switch, energy is stored in the first capacitor based on the induced voltage, and energy stored in the second capacitor is released, so that the output DC voltage And the switching circuit unit, the first series circuit unit, and the second series circuit unit are repeatedly caused to execute a fourth operation for storing energy in the inductor and storing energy in the inductor.

  As a result, the soft switching operation, which has been difficult to realize with the step-down circuit in the previous stage in the two-stage converter described in the prior art, is newly added to the secondary side (circuit on the second winding side) in the present invention. Since the switch and the second switch (semiconductor switch such as FET) can be easily driven, loss of the entire converter device can be reduced. Further, the output DC voltage is controlled by changing the on-duty of the first switch and the second switch without changing the switching frequency of the switching circuit unit, the first switch and the second switch (constant). Specifically, the voltage can be controlled to an arbitrary voltage within a range up to zero volts), so that the problem with the converter device configured to control the output DC voltage by changing the switching frequency is eliminated. As a result of being able to easily control the output voltage at the time of current, it is possible to avoid an excessive current from occurring when the output is short-circuited.

  In addition, the converter device according to the present invention includes a transformer having a first winding and a second winding, a pair of first DC terminal portions, and a pair of first connection lines connected to the first winding. A pair of first AC terminal portions connected, a pair of second DC terminal portions, a pair of second AC terminal portions connected to the second winding via a pair of second connection lines, and the pair Between the first DC terminal portion and the pair of first AC terminal portions, and converts the input DC voltage input to the pair of first DC terminal portions into an AC voltage to convert the pair of first DC terminal portions to each other. A switching circuit unit that outputs to one AC terminal unit, and a second circuit unit that is connected in series with the forward direction aligned and connected to one second AC terminal unit of the pair of second AC terminal units. It is composed of one rectifier element and a second rectifier element, and the current output end is connected to the first power line. A second input terminal connected to one second DC terminal part of the pair of second DC terminal parts, and a current input end part of the other second of the pair of second DC terminal parts via a second power line. A first series rectifier element connected to the DC terminal, an inductor inserted and connected to at least one of the first power line and the second power line, and connected in series with the forward direction aligned and connected to each other A second series rectifying element portion configured by a third rectifying element and a fourth rectifying element connected to the other second AC terminal portion of the pair of second AC terminal portions, and the first A first switch connected between the current output end of the series rectifying element unit and a current output end of the second series rectifying element unit; the current input end of the first series rectifying element unit; Connected between the current input end of the second series rectifier element A second switch; a capacitor connected in parallel to the second series rectifying element; an LC resonance circuit inserted and connected to at least one of the pair of first connection lines and the pair of second connection lines; , A control unit that converts the input DC voltage into an output DC voltage and outputs the output from the pair of second DC terminal units by performing switching control on the switching circuit unit, the first switch, and the second switch. And.

  In the converter device, the control unit executes the switching control to generate an induced voltage at which the other second AC terminal unit has a high potential with respect to the one second AC terminal unit. The first switch is turned off and the second switch is turned on to cause the capacitor to accumulate energy based on the induced voltage and to be accumulated in the inductor. A first operation for outputting the output DC voltage by releasing the energy being applied, and an induced voltage at which the other second AC terminal is at a high potential relative to the one second AC terminal. And causing the first switch and the second switch to be in an ON state, thereby energizing the capacitor based on the induced voltage. A second operation of causing the output DC voltage to be output by discharging the energy stored in the capacitor and storing the energy in the inductor, with respect to the other second AC terminal portion By causing the second winding to generate an induced voltage at which the one second AC terminal portion has a high potential, the first switch is turned on, and the second switch is turned off. A third operation for causing the capacitor to store energy based on an induced voltage and discharging the energy stored in the inductor to output the output DC voltage, and to the other second AC terminal portion An induced voltage at which the one second AC terminal portion has a high potential is generated in the second winding, and the first switch and the front switch By turning on the second switch, energy is stored in the capacitor based on the induced voltage, and the output DC voltage is output by discharging energy stored in the capacitor, and the inductor The fourth operation for storing energy is repeatedly executed by the switching circuit unit, the first switch, and the second switch.

  As a result, the soft switching operation, which has been difficult to realize with the step-down circuit in the previous stage in the two-stage converter described in the prior art, is newly added to the secondary side (circuit on the second winding side) in the present invention. Since the switch and the second switch (semiconductor switch such as FET) can be easily driven, loss of the entire converter device can be reduced. Further, the output DC voltage is controlled by changing the on-duty of the first switch and the second switch without changing the switching frequency of the switching circuit unit, the first switch and the second switch (constant). Specifically, the voltage can be controlled to an arbitrary voltage within a range up to zero volts), so that the problem with the converter device configured to control the output DC voltage by changing the switching frequency is eliminated. As a result of being able to easily control the output voltage at the time of current, it is possible to avoid an excessive current from occurring when the output is short-circuited. Furthermore, since the capacitor for storing and releasing energy can be integrated in the circuit on the second winding side, the converter according to the present invention requires two capacitors, the first capacitor and the second capacitor. Compared with the device, the circuit board on which the electronic component is mounted, and further the device itself can be downsized.

  According to the present invention, since the step-down circuit that is essential in the two-stage type converter is configured as a one-stage type that is unnecessary, the switching loss generated in the switch of the step-down circuit can be eliminated, Since it is easy to drive each switch disposed on the second winding side to perform a soft switching operation, it is possible to reduce the loss of the entire converter device. Further, the output DC voltage is controlled by changing the on-duty of each switch arranged on the second winding side (specifically, it is controlled to an arbitrary voltage within the range up to zero volts). Therefore, it is possible to avoid the generation of an excessive current when the output is short-circuited.

It is a block diagram of converter apparatus 1A. It is a wave form diagram for demonstrating operation | movement of 1 A of converter apparatuses. It is a block diagram for demonstrating operation | movement in the period T1 in FIG. 2 of 1 A of converter apparatuses. It is a block diagram for demonstrating the operation | movement in the period T2 in FIG. 2 of converter apparatus 1A. It is a block diagram for demonstrating the operation | movement in the period T3 in FIG. 2 of converter apparatus 1A. It is a block diagram for demonstrating operation | movement in the period T4 in FIG. 2 of 1 A of converter apparatuses. It is a block diagram of the other circuit example (switching circuit part 15) of the switching circuit part 7 of 1 A of converter apparatuses. It is a block diagram of the further another circuit example (switching circuit unit 16) of the switching circuit unit 7 of the converter device 1A. It is a block diagram of converter apparatus 1B. It is a wave form diagram for demonstrating operation | movement of the converter apparatus 1B. It is a block diagram for demonstrating operation | movement in the period T1 in FIG. 10 of the converter apparatus 1B. It is a block diagram for demonstrating operation | movement in the period T2 in FIG. 10 of the converter apparatus 1B. It is a block diagram for demonstrating operation | movement in the period T3 in FIG. 10 of the converter apparatus 1B. It is a block diagram for demonstrating the operation | movement in the period T4 in FIG. 10 of the converter apparatus 1B.

  Hereinafter, embodiments of a converter device will be described with reference to the drawings.

  First, a configuration of a converter device 1A as an example of the converter device will be described with reference to FIG. This converter device 1A includes a transformer 2, a pair of first DC terminal portions 3a and 3b, a pair of first AC terminal portions 4a and 4b, a pair of second DC terminal portions 5a and 5b, and a pair of second AC terminal portions 6a. , 6b, switching circuit unit 7, series rectifying element unit 8, inductor 9, first series circuit unit 10, second series circuit unit 11, LC resonance circuit 12, and control unit 13, and a pair of first DC terminal units An input DC voltage Vin input between 3a and 3b (in this example, as an example, a voltage output from the DC power supply PS as shown in FIG. 1) is converted into an output DC voltage Vout and a pair of The second DC terminal portions 5a and 5b can be output (specifically, supplied to a load LD connected to the second DC terminal portions 5a and 5b).

  In detail, the transformer 2 is formed in a common magnetic core (not shown) as an example in this example, and two windings (a first winding 2a and a second winding 2b) that are magnetically coupled to each other. ). The pair of first AC terminal portions 4a and 4b are connected to the first winding 2a via a pair of first connection lines L1a and L1b. In this example, the LC resonance circuit 12 is inserted and connected to the first connection lines L1a and L1b. Specifically, in this example, the LC resonance circuit 12 includes a resonance capacitor 12a that is inserted and connected to the first connection line L1a, and a resonance inductor 12b that is inserted and connected to the first connection line L1b. Yes. For this reason, in this example, the first AC terminal portion 4a is connected to one end of the first winding 2a via the first connection line L1a to which the resonant capacitor 12a is inserted and connected, and the first AC terminal portion 4b is The resonance inductor 12b is connected to the other end of the first winding 2a via the first connection line L1b to which the resonance inductor 12b is inserted and connected. Although not shown, the resonant capacitor 12a and the resonant inductor 12b are inserted and connected to the first connection line L1b, and the resonant inductor 12b is inserted and connected to the first connection line L1a. It can also be configured.

  The pair of second AC terminal portions 6a and 6b are connected to the second winding 2b via a pair of second connection lines L2a and L2b. In this example, the LC resonance circuit 12 is inserted and connected to the first connection lines L1a and L1b as described above, but is not limited to this configuration, and the first connection lines L1a and L1b and the second connection lines are not limited to this configuration. It is only necessary to be inserted and connected to at least one of the connection lines L2a and L2b.

  The switching circuit unit 7 is disposed between the pair of first DC terminal units 3a and 3b and the pair of first AC terminal units 4a and 4b, and converts the input DC voltage Vin into the AC voltage V1 to be the first. Output between the AC terminal portions 4a and 4b. In this example, as an example, the switching circuit unit 7 is configured by a half-bridge switching circuit. Specifically, the switching circuit unit 7 includes a switch 7a and a switch that are connected to each other at one of the first AC terminal units 4a and 4b (in this example, the first AC terminal unit 4a). A capacitor series of a capacitor 7c and a capacitor 7d connected to each other at the switch series circuit of 7b and the other first AC terminal portion (in this example, the first AC terminal portion 4b) of the first AC terminal portions 4a and 4b. It is composed of a circuit.

  One end of the switch series circuit (in this example, the drain terminal of the switch 7a) is one of the first DC terminal parts (in this example, the first DC terminal part) of the pair of first DC terminal parts 3a and 3b. It is connected to the DC terminal part 3a). The other end of the switch series circuit (in this example, the source terminal of the switch 7b) is connected to the other first DC terminal of the pair of first DC terminals 3a and 3b (in this example, the first terminal). It is connected to the DC terminal part 3b). One end of the capacitor series circuit (one end of the capacitor 7c in this example) is connected to the first DC terminal 3a, and the other end of the capacitor series circuit (the other end of the capacitor 7d in this example). Note that one end of the capacitor 7d is connected to the other end of the capacitor 7c by the first AC terminal portion 4b) and is connected to the first DC terminal portion 3b. That is, the capacitor series circuit is connected in parallel to the switch series circuit.

  The series rectifying element unit 8 includes an n-channel FET 8a that functions as a first rectifying element and is connected in series with the forward direction aligned, and an n-channel FET 8b that functions as a second rectifying element. In this example, each of the FETs 8a and 8b has a connection point (a source terminal of the FET 8a and a drain terminal of the FET 8b) that is one second AC terminal part (in this example, one of the pair of second AC terminal parts 6a and 6b). Are connected to the second AC terminal portion 6b). Each FET 8a, 8b is driven so as to perform a synchronous rectification operation as will be described later, and functions as a rectifier equivalent to a diode. The series rectifying element unit 8 has a current output end (in this example, the drain terminal of the FET 8a (also the cathode terminal of the body diode in the FET 8a)) via a first power line Lp1 as a pair of second DC terminals. Connected to one second DC terminal portion (in this example, the second DC terminal portion 5a) of the portions 5a, 5b, and a current input end portion (in this example, the source terminal of the FET 8b (the body diode in the FET 8b) Is connected to the other second DC terminal part (in this example, the second DC terminal part 5b) of the pair of second DC terminal parts 5a and 5b via the second power line Lp2. Has been. Since the FET 8a and the FET 8b function as rectifying elements as described above, they can be replaced with single diodes having the same polarity as the body diode.

  The inductor 9 is inserted and connected to at least one of the first power line Lp1 and the second power line Lp2. In this example, as an example, the inductor 9 is inserted and connected to the first power line Lp1, but although not shown, the inductor 9 may be inserted and connected to the second power line Lp2. The configuration may be such that both Lp1 and the second power line Lp2 are inserted and connected separately. Although not shown, it is also possible to employ a configuration in which a capacitor that smoothes the output DC voltage Vout is connected between the second DC terminal portions 5a and 5b.

  The first series circuit unit 10 includes a switch 10a as a first switch and a capacitor 10b as a first capacitor connected in series. In this example, as an example, the switch 10a is composed of an n-channel FET, and the drain terminal of the switch 10a and one terminal of the capacitor 10b are connected. The first series circuit unit 10 has one end (in this example, the source terminal of the switch 10a) connected to the current output end of the series rectifying element unit 8 and the other end (in this example, the capacitor). The other terminal of 10b is connected to the other second AC terminal part (in this example, the second AC terminal part 6a) of the pair of second AC terminal parts 6a, 6b. Instead of this configuration, the first series circuit unit 10 includes a capacitor 10b on the current output end side of the series rectifying element unit 8 and a switch 10a on the second AC terminal unit 6a side in the same direction. An arranged configuration may be used.

  The second series circuit unit 11 includes a switch 11a as a second switch and a capacitor 11b as a second capacitor connected in series. In this example, as an example, the switch 11a is composed of an n-channel FET, and the source terminal of the switch 11a and one terminal of the capacitor 11b are connected. The second series circuit unit 11 has one end (in this example, the other terminal of the capacitor 11b) connected to the other second AC terminal 6a and the other end (in this example, the switch 11a). Is connected to the current input end of the series rectifying element 8. Instead of this configuration, the second series circuit unit 11 is provided with the switch 11a in the same direction on the second AC terminal unit 6a side, and the capacitor 11b on the current input end side of the series rectifying element unit 8. An arranged configuration may be used.

  The LC resonance circuit 12 is inserted and connected to the first connection lines L1a and L1b as an example, but is not limited to this configuration. Of the first connection lines L1a and L1b and the second connection lines L2a and L2b, It is only necessary to be inserted and connected to at least one of the above.

  The control unit 13 outputs drive signals S1, S2, S3, and S4 to the switches 10a and 11a and the FETs 8a and 8b that perform synchronous rectification driving, and also to the switches 7a and 7b of the switching circuit unit 7. Then, the drive signals S11 and S12 are output (output at an on-duty of 0.5), thereby executing switching control for the switches 10a and 11a, the FETs 8a and 8b, and the switches 7a and 7b. In this example, each switch 7a, 7b, 10a, 11a is comprised of FET as described above, and each rectifier of the series rectifier element 8 is also comprised of FETs 8a, 8b. Provided with appropriate drive circuits (not shown) for the switches 7a, 7b, 10a, 11a and the FETs 8a, 8b, the FETs constituting the switches 7a, 7b, 10a, 11a and the gates and sources of the FETs 8a, 8b In addition, the drive signals S11, S12, S1, S2, S3, and S4 are output as positive voltage signals based on the potential of the source terminal. Further, the drive signals S11 and S12 are not illustrated but are provided with a dead time.

  Next, the operation of the converter device 1A will be described with reference to FIGS.

  The controller 13 repeats the drive signals S11, S12, S1 to S4 to the switches 10a, 11a, 7a, 7b and the FETs 8a, 8b with the output state from the period T1 to the period T4 shown in FIG. 2 as one cycle. Output. Note that “ON” and “OFF” in FIG. 2 indicate the ON / OFF states of the switches 10a, 11a, 7a, 7b and FETs 8a, 8b corresponding to the drive signals S11, S12, S1, S2, S3, S4. Show. Hereinafter, the operation will be described in each period T1, T2, T3, T4. The FETs 8a and 8b function as rectifier elements (diodes) as described above throughout the entire cycle by being driven by the corresponding drive signals S3 and S4. Therefore, in the following description of the operation, the diode 8a 8b, detailed description of each of them will be omitted, and in FIG. 3 to FIG.

  First, in the period T1, as shown in FIG. 2, the drive signal S11 is switched from zero volts (an example of a voltage less than the gate threshold voltage) to a positive voltage (a voltage equal to or higher than the gate threshold voltage). Thus, the switch 7a shifts from the OFF state to the ON state. Also, as shown in FIG. 2, when the drive signals S1 and S12 are switched from the positive voltage to zero volts, the switches 10a and 7b shift from the ON state to the OFF state as shown in FIGS. Further, since the other drive signal S2 is maintained at a positive voltage as shown in FIG. 2, the switch 11a continues to be in the ON state as shown in FIGS. That is, when the switch 7a is ON and the switch 7b is OFF, the switch 10a is OFF and the switch 11a is ON.

  In this case, in the circuit on the first winding 2a side (first DC terminal portions 3a, 3b side), the switch 7a, the resonance capacitor 12a, the first winding 2a, the ON state from the DC power source PS (input DC voltage Vin), A current path returning to the DC power source PS via the resonant inductor 12b and the capacitor 7d is formed, and the current Ia flows through this current path. Thereby, the capacitor 7d is charged (energy is stored in the capacitor 7d). Also, a current path is formed from the capacitor 7c to the capacitor 7c via the switch 7a in the ON state, the resonance capacitor 12a, the first winding 2a, and the resonance inductor 12b. For this reason, in the periods T3 and T4, energy accumulated in the capacitor 7c is released as will be described later, whereby the current Ib flows in the direction indicated by the arrow in FIG.

  Further, since these two current paths include the LC resonance circuit 12 (resonance capacitor 12a and resonance inductor 12b), the waveforms of the currents Ia and Ib are not shown, but they are resonance waveforms (sine-wave waveforms). ) As a result, the waveform of the current (combined current (Ia + Ib)) in the switch 7a and the first winding 2a in which the currents Ia and Ib simultaneously flow in the same direction is also shown in FIG. Waveform). Further, since the combined current (Ia + Ib) flows through the first winding 2a in this direction, each series circuit portion is connected to the connection point (second AC terminal portion 6b) of the diodes 8a and 8b in the second winding 2b. A voltage (induced voltage V2) at which the connection point (second AC terminal portion 6a) between 10 and 11 becomes high potential is induced.

  On the other hand, in the circuit on the second winding 2b side (the second DC terminal portions 5a and 5b side), when the switch 10a shifts to the OFF state, the switch 10a in the ON state is changed as described later in the periods T3 and T4. Charging of the capacitor 10b that has been executed via the terminal (the potential of the terminal on the side of the current output end of the series rectifying element unit 8 in the capacitor 10b is higher than the potential of the terminal of the capacitor 10b on the side of the second winding 2b) Charging) is stopped. In addition, when current Ij described later flows to inductor 9 in period T4, energy stored in inductor 9 is released, so that load LD, diode 8b, and diode 8a are discharged from inductor 9 as shown in FIG. A current Ic flows through the current path that passes back to the inductor 9 (the output DC voltage Vout is output to the load LD).

  Further, as described above, due to the inflow of the current (Ia + Ib) to the first winding 2a, the induced voltage V2 at which the second AC terminal portion 6a is at a higher potential than the second AC terminal portion 6b is Induced in two windings 2b. Therefore, in the circuit on the second winding 2b side, since the switch 11a has shifted to the ON state, the second winding 2b passes through the capacitor 11b, the ON state switch 11a, and the diode 8b from the second winding 2b. A current path returning to the line 2b is formed, and based on the induced voltage V2 having the above polarity (energy output from the second winding 2b), as shown in FIG. Id flows. Thereby, the capacitor 11b is charged so that the potential of the terminal on the second winding 2b side of the capacitor 11b becomes a high potential with reference to the potential of the terminal on the current input end side of the series rectifying element unit 8 in the capacitor 11b. (Energy is stored in the capacitor 11b).

  Thus, in the period T1, the circuit on the first winding 2a side supplies the combined current (Ia + Ib) to the first winding 2a based on the energy released from the capacitor 7c and the energy from the input DC voltage Vin. And an operation of charging the capacitor 7d with energy from the input DC voltage Vin. The circuit on the second winding 2b side supplies the current Ic to the load LD (outputs the output DC voltage Vout) based on the energy released from the inductor 9, and the second winding 2b The operation of charging the capacitor 11b with the induced voltage V2 (energy from the second winding 2b) induced with the polarity of is performed as the first operation.

  Next, in the period T2, as shown in FIG. 2, the drive signal S1 is switched from zero volts to a positive voltage, so that the switch 10a shifts from the OFF state to the ON state as shown in FIGS. Note that the other switches 7a, 7b, and 11a are in the ON / OFF state during the period T1 because the corresponding drive signals are the same as those during the period T1. That is, both the switches 10a and 11a are in the ON state when the switch 7a is in the ON state and the switch 7b is in the OFF state.

  In this case, in the circuit on the first winding 2a side, as shown in FIG. 4, each switch 7a, 7b continues the ON / OFF state at the time T1, so the same current path as at the time T1 is obtained. It is formed continuously. For this reason, the operation of supplying the combined current (Ia + Ib) to the first winding 2a and the operation of charging the capacitor 7d with the energy from the input DC voltage Vin are continued.

  On the other hand, in the circuit on the second winding 2b side, as shown in FIG. 4, based on the induced voltage V2 induced in the second winding 2b with the same polarity as in the period T1, the second winding 2b to the capacitor 11b. The current Id continues to flow through the current path that returns to the second winding 2b via the switch 11a and the diode 8b, and charging of the capacitor 11b is continued. Further, when the switch 10a shifts to the ON state, a new current path is formed from the capacitor 10b to the capacitor 10b via the switch 10a, the inductor 9, the load LD, the ON state switch 11a, and the capacitor 11b. Thereby, based on the energy accumulated in the capacitor 10b, the current Ie flows in the direction of the arrow through this new current path (the output DC voltage Vout is output to the load LD). Further, when the current Ie flows through the inductor 9, energy is accumulated in the inductor 9. Since the currents Id and Ie flow in opposite directions in the second series circuit unit 11 (the switch 11a and the capacitor 11b) in which these two current paths overlap, the combined current (Ie−Id) of the currents Id and Ie is switched. It flows to 11a.

  As described above, in the period T2, the circuit on the first winding 2a side supplies the combined current (Ia + Ib) to the first winding 2a based on the energy released from the capacitor 7c and the energy from the input DC voltage Vin. The operation of supplying and the operation of charging the capacitor 7d with the energy from the input DC voltage Vin are continuously executed. Further, the circuit on the second winding 2b side continues the operation of charging the capacitor 11b with the induced voltage V2 (energy from the second winding 2b) induced in the second winding 2b, and discharges from the capacitor 10b. Based on the generated energy, the operation of supplying the current Ie to the load LD (outputting the output DC voltage Vout) and storing the energy in the inductor 9 is executed as the second operation.

  Subsequently, in the period T3, the drive signal S12 is switched from zero volts to a positive voltage as shown in FIG. 2, so that the switch 7b shifts from the OFF state to the ON state as shown in FIGS. Also, as shown in FIG. 2, when the drive signals S2 and S11 are switched from the positive voltage to zero volts, the switches 11a and 7a shift from the ON state to the OFF state as shown in FIGS. Further, as shown in FIG. 2, the other drive signal S1 is maintained at a positive voltage, so that the switch 10a continues to be in the ON state as shown in FIGS. That is, when the switch 7a is in the OFF state and the switch 7b is in the ON state (in a state opposite to the periods T1 and T2), the switch 10a is in the ON state and the switch 11a is in the OFF state.

  In this case, in the circuit on the first winding 2a side, when the switch 7a shifts to the OFF state, the capacitor 7c, the resonant inductor 12b, the first winding 2a, and the resonant capacitor 12a from the DC power source PS (input DC voltage Vin). And a current path that returns to the DC power source PS via the ON-state switch 7b is formed, and the current If flows through this current path. Thereby, the capacitor 7c is charged (energy is stored in the capacitor 7c).

  Further, when the switch 7b shifts to the ON state, a current path from the capacitor 7d to the capacitor 7d via the resonant inductor 12b, the first winding 2a, the resonant capacitor 12a, and the ON state switch 7b is also formed. . For this reason, the energy accumulated in the capacitor 7d in the periods T1 and T2 is released, so that the current Ig flows through the current path in the direction indicated by the arrow in FIG.

  Further, since the LC resonance circuit 12 is included in the two current paths, the waveforms of the currents If and Ig are not shown, but become resonance waveforms (sine wave-like waveforms). As a result, the current (synthetic current (If + Ig)) in the switch 7b and the first winding 2a in which the currents If and Ig simultaneously flow in the same direction is also a resonance waveform (sine wave waveform) as shown in FIG. It becomes. Further, since the combined current (If + Ig) flows through the first winding 2a in this direction, the second winding 2b has a voltage (a voltage at which the second AC terminal portion 6b is at a higher potential than the second AC terminal portion 6a). An induced voltage V2) is induced.

  On the other hand, in the circuit on the second winding 2b side, when the switch 11a shifts to the OFF state (turns off), the charging to the capacitor 11b that has been executed via the ON switch 11a in the periods T1 and T2 ( The charging at which the potential of the terminal on the second winding 2b side of the capacitor 11b becomes a high potential with respect to the potential of the terminal on the current input end side of the series rectifying element portion 8 in the capacitor 11b is stopped.

  In addition, as the current Ie flows through the inductor 9 in the period T2, the energy stored in the inductor 9 is released, and as shown in FIG. 5, the inductor 9 passes through the load LD, the diode 8b, and the diode 8a. Then, the current Ic flows through the current path returning to the inductor 9 (the output DC voltage Vout is output to the load LD).

  Further, as described above, due to the inflow of the current (If + Ig) to the first winding 2a, the induced voltage V2 at which the second AC terminal portion 6b has a higher potential than the second AC terminal portion 6a is the first voltage V2. Induced in two windings 2b. For this reason, in the circuit on the second winding 2b side, since the switch 10a has shifted to the ON state, the second winding 2b passes through the diode 8a, the ON state switch 11a, and the capacitor 10b. A current path returning to the line 2b is formed, and based on the induced voltage V2 of the above polarity (energy output from the second winding 2b), as shown in FIG. Ih flows. Thereby, the capacitor 10b is charged such that the potential of the terminal on the current output end side of the series rectifying element unit 8 in the capacitor 10b becomes a high potential with reference to the potential of the terminal on the second winding 2b side in the capacitor 10b. (Energy is stored in the capacitor 10b).

  Thus, in the period T3, the circuit on the first winding 2a side supplies the combined current (If + Ig) to the first winding 2a based on the energy released from the capacitor 7d and the energy from the input DC voltage Vin. And the operation of charging the capacitor 7c with the energy from the input DC voltage Vin. Further, the circuit on the second winding 2b side is supplied to the load LD based on the energy released from the inductor 9 (outputs the output DC voltage Vout), and is induced in the second winding 2b. The operation of charging the capacitor 10b with the induced voltage V2 (energy from the second winding 2b) is executed as the third operation.

  Next, in the period T4, as shown in FIG. 2, when the drive signal S2 is switched from zero volts to a positive voltage, the switch 11a shifts from the OFF state to the ON state as shown in FIGS. Note that each of the other switches continues the ON / OFF state at the period T3 because the corresponding drive signal is the same as that at the period T3. That is, when the switch 7a is in the OFF state and the switch 7b is in the ON state, both the switches 10a and 11a are in the ON state.

  In this case, in the circuit on the first winding 2a side, as shown in FIG. 6, since the switches 7a and 7b continue the ON / OFF state at the time T3, the same current path as at the time T3 is obtained. It is formed continuously. For this reason, the operation of supplying the combined current (If + Ig) to the first winding 2a and the operation of charging the capacitor 7c with the energy from the input DC voltage Vin are continued.

  On the other hand, in the circuit on the second winding 2b side, as shown in FIG. 6, based on the induced voltage V2 induced in the second winding 2b with the same polarity as in the period T3, the second winding 2b to the diode 8a. The current Ih continues to flow through the current path returning to the second winding 2b via the switch 10a and the capacitor 10b in the ON state, and charging of the capacitor 10b is continued. Further, when the switch 11a shifts to the ON state, a new current path is formed from the capacitor 11b to the capacitor 11b via the capacitor 10b, the ON state switch 10a, the inductor 9, the load LD, and the ON state switch 11a. Is done. Thereby, based on the energy stored in the capacitor 11b, the current Ij flows through this new current path (the output DC voltage Vout is output to the load LD). Further, when the current Ij flows through the inductor 9, energy is accumulated in the inductor 9. Since the currents Ih and Ij flow in opposite directions in the first series circuit unit 10 (the switch 10a and the capacitor 10b) in which these two current paths overlap, the combined current (Ih−Ij) of the currents Ih and Ij is switched. It flows to 10a.

  As described above, in the period T4, the circuit on the first winding 2a side supplies the combined current (If + Ig) to the first winding 2a based on the energy released from the capacitor 7d and the energy from the input DC voltage Vin. The operation of supplying and the operation of charging the capacitor 7c with the energy from the input DC voltage Vin are continuously executed. Further, the circuit on the second winding 2b side continues the operation of charging the capacitor 10b with the induced voltage V2 (energy from the second winding 2b) induced in the second winding 2b, and discharges from the capacitor 11b. Based on the generated energy, the current Ij is supplied to the load LD (output DC voltage Vout is output), and the operation of accumulating energy in the inductor 9 is executed as the fourth operation.

  Thereby, one cycle constituted by the period T1 to the period T4 is completed.

The output DC voltage Vout is expressed by the following equation. Note that n is the turn ratio (Ns / Np) of the first winding 2a (turn number Np) and the second winding 2b (turn number Ns), and D is the on-duty of the switches 10a and 11a. .
Vout = n × Vin × (2 × D−1)

  As is apparent from this equation, the converter device 1A basically depends on the value of n, but by setting the on-duty D to a value within the range of 0.5 ≦ D <1, the output DC voltage Vout Functions as a Buck type (step-down type) converter in which becomes smaller than the input DC voltage Vin. Further, as apparent from this equation, in the converter device 1A, by changing the on-duty D for the switches 10a and 11a without changing the switching frequency of the switches 7a, 7b, 10a, and 11a, It is possible to control the output DC voltage Vout (specifically, control to an arbitrary voltage within a range up to zero volts).

  As described above, in the converter device 1A, the circuit on the first winding 2a side includes the switching circuit unit 7 that converts the input DC voltage Vin into the AC voltage V1 and outputs the AC voltage V1 to the first AC terminal units 4a and 4b. The circuit on the second winding 2b side includes the second winding 2b, the second DC terminal portions 5a and 5b, the second AC terminal portions 6a and 6b, the series rectifying element portion 8, the inductor 9, and the first winding 2b. A series circuit unit 10 and a second series circuit unit 11 are provided and are connected and configured as shown in FIG. The LC resonance circuit 12 is inserted and connected between the first winding 2a and the first AC terminal portions 4a and 4b.

  Therefore, according to the converter device 1A, the step-down circuit that is essential in the two-stage type converter described in the prior art is configured as a one-stage type that is unnecessary. Switching loss can be eliminated. Further, according to the converter device 1A, the switches 10a and 11a constituting the circuit on the second winding 2b side are driven so that the soft switching operation can be achieved by the drive signals S1 and S2 supplied from the control unit 13. Therefore, the loss as a whole of the converter device 1A can be reduced. Further, according to the converter device 1A, the switches 10a and 11a constituting the circuit on the second winding 2b side are driven by the drive signals S1 and S2 supplied from the control unit 13, whereby the second winding Since the circuit on the 2b side performs the first to fourth operations in each of the periods T1, T2, T3, and T4, the switching frequency of each of the switches 7a, 7b, 10a, and 11a is not changed (assumed to be constant). However, the output DC voltage Vout can be controlled by changing the on-duty of the switches 10a and 11a (specifically, it can be controlled to any voltage within the range up to zero volts). As a result, it is possible to easily perform the output voltage control at the time of overcurrent while solving the problem in the converter device configured to control the output DC voltage Vout by changing the switching frequency. It can be avoided.

  In addition, although the example which comprises the switching circuit part 7 by a half bridge switching circuit was given and demonstrated, the switching circuit part 7 is not limited to this example. For example, a full bridge in which switches 7e and 7f (the same n-channel FET as the switches 7a and 7b) are provided instead of the capacitors 7c and 7d in the switching circuit unit 7 as in the switching circuit unit 15 shown in FIG. A switching circuit can also be used. In this case, as shown in FIG. 7, the switch 7f is driven by the same drive signal S11 as that of the switch 7a and shifts to the ON state together with the switch 7a in the periods T1 and T2, and in the periods T3 and T4, the switch 7f It shifts to the OFF state together with 7a. The switch 7e is driven by the same drive signal S12 as that of the switch 7b, and shifts to the OFF state together with the switch 7b in the periods T1 and T2, and shifts to the ON state together with the switch 7b in the periods T3 and T4.

  Therefore, even in the configuration including the switching circuit unit 15, the converter device 1 </ b> A performs switching by causing the circuit on the second winding 2 b side to perform the first operation to the fourth operation described above in each period T <b> 1 to T <b> 4. The same effects as those provided by the circuit unit 7 can be obtained.

  Moreover, the switching circuit unit 7 can also be configured by a single-end push-pull circuit in which the capacitor 7c in the switching circuit unit 7 is deleted as in the switching circuit unit 16 shown in FIG. In this case, as shown in FIG. 8, the switch 7a is driven by the drive signal S11 and shifts to the ON state during the periods T1 and T2, and shifts to the OFF state during the periods T3 and T4. Further, the switch 7b is driven by the drive signal S12, and shifts to the OFF state during the periods T1 and T2, and shifts to the ON state during the periods T3 and T4. Therefore, even in the configuration including the switching circuit unit 16, the converter device 1 </ b> A performs switching by causing the circuit on the second winding 2 b side to perform the first to fourth operations described above in each period T <b> 1 to T <b> 4. The same effects as those provided by the circuit unit 7 can be obtained. In the converter device 1B described later, any of the switching circuit units 7, 15, and 16 may be employed in the circuit on the first winding 2a side.

  Note that the circuit on the second winding 2b side is not limited to the above configuration employed in the converter device 1A, and may be a circuit described later employed in the converter device 1B shown in FIG. 9, for example. . Hereinafter, the converter device 1B will be described with reference to FIGS. In addition, about the same structure as converter apparatus 1A, the same code | symbol is attached | subjected and the overlapping description is abbreviate | omitted.

  First, the configuration of converter device 1B will be described with reference to FIG. The converter device 1B includes a transformer 2, a pair of first DC terminal portions 3a and 3b, a pair of first AC terminal portions 4a and 4b, a pair of second DC terminal portions 5a and 5b, and a pair of second AC terminal portions 6a. , 6b, one of the switching circuit units 7, 15, 16 (in the figure, as an example, the switching circuit unit 7), a series rectifying device unit 8 as a first series rectifying device unit, an inductor 9, and a second series rectifying device A series rectifying element unit 17 as an element unit, a switch 10a as a first switch, a switch 11a as a second switch, a capacitor 18, an LC resonance circuit 12, and a control unit 13, and a pair of first DC terminal units 3a, The input DC voltage Vin input between 3b is converted into the output DC voltage Vout and output from between the pair of second DC terminal portions 5a and 5b (specifically, the second DC terminal portions 5a and 5b). And it is configured to be supplied) to the connected load LD.

  The series rectifying element unit 17 is connected in series with the forward direction aligned, and the connection point between them is the other second AC terminal unit (second in this example, the second AC terminal unit 6a, 6b). The n-channel FET 17a functioning as the third rectifying element and the n-channel FET 17b functioning as the fourth rectifying element connected to the AC terminal portion 6a). Each FET 17a, 17b has a connection point (a source terminal of the FET 17a and a drain terminal of the FET 17b) connected to the second AC terminal portion 6a. Each FET 17a, 17b is driven to perform a synchronous rectification operation as will be described later, and functions as a rectifier equivalent to a diode. Since the FET 17a and the FET 17b function as rectifying elements in this way, they can be replaced with single diodes having the same polarity as the body diode. Therefore, hereinafter, for ease of understanding, the FET 17a and the FET 17b are also referred to as a diode 17a and a diode 17b in the following, and in FIG. 11 to FIG. 14, they are represented by diode symbols as in the FETs 8a and 8b.

  The switch 10a includes a current output end of the series rectifier element 8 (in this example, the drain terminal of the FET 8a) and a current output end of the series rectifier element 17 (in this example, the drain terminal of the FET 17a (the body in the FET 17a). It is also connected to the cathode terminal of the diode)). In this example, the switch 10a is composed of an n-channel FET, and its source terminal is connected to the current output end of the series rectifying element unit 8, and its drain terminal is connected to the current output end of the series rectifying element unit 17. By being connected, they are connected between the current output end portions of the series rectifying element portions 8 and 17.

  The switch 11a includes a current input end of the series rectifying element unit 8 (in this example, the source terminal of the FET 8b) and a current input end of the series rectifying element unit 17 (in this example, the source terminal of the FET 17b (the body in the FET 17b). It is also connected to the anode terminal of the diode)). In this example, the switch 11a is composed of an n-channel FET, and its drain terminal is connected to the current input end of the series rectifying element unit 8, and its source terminal is connected to the current input end of the series rectifying element unit 17. By being connected, they are connected between the current input end portions of the series rectifying element portions 8 and 17.

  The capacitor 18 is connected in parallel to the series rectifying element unit 17.

  The control unit 13 outputs drive signals S1, S2, S3, S4, S5, and S6 to the switches 10a and 11a and the FETs 8a, 8b, 17a, and 17b that perform synchronous rectification driving, and the switching circuit unit 7 Drive signals S11 and S12 are output to the respective switches 7a and 7b (output at an on-duty of 0.5), whereby each switch 10a and 11a, each FET 8a, 8b, 17a and 17b, and each switch 7a. , 7b. In this example, each switch 7a, 7b, 10a, 11a is composed of FET as described above, and each rectifier element of the series rectifier elements 8 and 17 is also composed of FETs 8a, 8b, 17a, 17b. The control unit 13 includes appropriate drive circuits (not shown) for the switches 7a, 7b, 10a, and 11a and the FETs 8a, 8b, 17a, and 17b, and the FETs that configure the switches 7a, 7b, 10a, and 11a. Each drive signal S11, S12, S1, S2, S3, S4, S5, S6 is output as a positive voltage signal based on the potential of the source terminal between the gate and source of each FET 8a, 8b, 17a, 17b. Shall.

  Next, the operation of converter device 1B will be described with reference to FIGS.

  The control unit 13 sets the drive signals S11, S12, S1 to S6 to the output states from the period T1 to the period T4 shown in FIG. 10 as one cycle, and switches 10a, 11a, 7a, 7b and FETs 8a, 8b, 17a. , 17b are repeatedly output. Note that “ON” and “OFF” in FIG. 10 indicate the switches 10a, 11a, 7a, 7b and FETs 8a, 8b, 17a corresponding to the drive signals S11, S12, S1, S2, S3, S4, S5, S6. , 17b shows the ON / OFF state. Hereinafter, the operation will be described in each period T1, T2, T3, T4. Since the FETs 8a, 8b, 17a, and 17b are driven by the corresponding drive signals S3, S4, S5, and S6 to function as rectifier elements (diodes) as described above throughout the entire cycle, In the explanation of the operation, the diodes 8a, 8b, 17a, and 17b are referred to, and detailed explanations thereof are omitted. The circuit on the first winding 2a side of the converter device 1B has the same configuration as the circuit on the first winding 2a side of the converter device 1A. Further, the timing of each drive signal S11, S12 in each period T1, T2, T3, T4 is also the same as that of the converter device 1A. As a result, the circuit on the first winding 2a side of the converter device 1B performs the same operation as the circuit on the first winding 2a side of the converter device 1A in each period T1, T2, T3, T4. The detailed description of the operation of the circuit on the first winding 2a side will be omitted, and the operation of the circuit on the second winding 2b side will be mainly described.

  First, in the period T1, the circuit on the first winding 2a side, like the converter device 1A, generates a combined current in the first winding 2a based on the energy released from the capacitor 7c and the energy from the input DC voltage Vin. An operation of supplying (Ia + Ib) and an operation of charging the capacitor 7d with energy from the input DC voltage Vin are executed. Due to the inflow of the current (Ia + Ib) to the first winding 2a, as shown in FIG. 11, an induced voltage V2 at which the second AC terminal portion 6a has a higher potential than the second AC terminal portion 6b is generated. It is induced in the second winding 2b.

  In the circuit on the second winding 2b side, when the switch 11a is in the ON state, the switch 10a shifts from the ON state to the OFF state, whereby the diode 17a, the capacitor 18, and the ON state switch 11a from the second winding 2b. And the current path which returns to the 2nd coil | winding 2b via the diode 8b is formed. Therefore, based on the induced voltage V2 having the above polarity (energy output from the second winding 2b), as shown in FIG. 11, a current Id flows in this current path in the direction indicated by the arrow. As a result, the capacitor 18 has a potential at the terminal on the current output end side of the series rectifying element portion 17 in the capacitor 18 as a reference with the potential at the terminal on the current input end side of the series rectifying element portion 17 in the capacitor 18 as a reference. (Energy is stored in the capacitor 18). Similarly to the converter device 1A, when the current Ij flows through the inductor 9 during the period T4, the energy accumulated in the inductor 9 is released, and as shown in FIG. The current Ic flows through the current path that returns to the inductor 9 via 8b and the diode 8a (the output DC voltage Vout is output to the load LD).

  Thus, in the period T1, the circuit on the second winding 2b side supplies the current Ic (outputs the output DC voltage Vout) to the load LD based on the energy released from the inductor 9, The operation of charging the capacitor 18 with the induced voltage V2 (energy from the second winding 2b) induced in the two windings 2b with the above polarity is executed as the first operation.

  Next, in the period T2, the circuit on the first winding 2a side is combined with the first winding 2a based on the energy released from the capacitor 7c and the energy from the input DC voltage Vin, similarly to the converter device 1A. The operation of supplying the current (Ia + Ib) and the operation of charging the capacitor 7d with the energy from the input DC voltage Vin are continuously executed. Therefore, as shown in FIG. 12, an induced voltage V2 at which the second AC terminal portion 6a is at a high potential with respect to the second AC terminal portion 6b is continuously induced in the second winding 2b.

  In the circuit on the second winding 2b side, since the switch 11a continues to be in the ON state, as shown in FIG. 12, the induced voltage V2 induced in the second winding 2b has the same polarity as that in the period T1. Based on this, the current Id continuously flows from the second winding 2b through the diode 17a, the capacitor 18, the ON switch 11a and the diode 8b to the second winding 2b, and the capacitor 18 is charged. Will continue. Further, when the switch 10a shifts from the OFF state to the ON state, a new current path from the capacitor 18 to the capacitor 18 via the ON state switch 10a, the inductor 9, the load LD, and the ON state switch 11a is formed. Is done. Thereby, based on the energy accumulated in the capacitor 18, the current Ie flows in the direction of the arrow in this new current path (the output DC voltage Vout is output to the load LD). Further, when the current Ie flows through the inductor 9, energy is accumulated in the inductor 9.

  In addition, since the currents Id and Ie flow in opposite directions through the switch 11a where these two current paths overlap, a combined current (Ie-Id) of the currents Id and Ie flows.

  Thus, in the period T2, the circuit on the second winding 2b side continues the operation of charging the capacitor 18 with the induced voltage V2 (energy from the second winding 2b) induced in the second winding 2b. At the same time, based on the energy released from the capacitor 18, the current Ie is supplied to the load LD (output DC voltage Vout is output), and the operation of storing energy in the inductor 9 is executed as the second operation.

  Subsequently, in the period T3, the circuit on the first winding 2a side is combined with the first winding 2a based on the energy released from the capacitor 7d and the energy from the input DC voltage Vin, similarly to the converter device 1A. An operation of supplying the current (If + Ig) in the opposite direction to the combined current (Ia + Ib) and an operation of charging the capacitor 7c with the energy from the input DC voltage Vin are executed. Therefore, as shown in FIG. 13, an induced voltage V2 at which the second AC terminal portion 6b has a higher potential than the second AC terminal portion 6a is induced in the second winding 2b.

  In the circuit on the second winding 2b side, when the switch 10a is in the ON state, the switch 11a shifts from the ON state to the OFF state, so that the diode 8a from the second winding 2b, the switch 10a in the ON state, and the capacitor 18 are switched. A current path that returns to the second winding 2b via the diode 17b is formed. Therefore, based on the induced voltage V2 having the above polarity (energy output from the second winding 2b), as shown in FIG. 13, a current Ih flows through the current path in the direction indicated by the arrow. As a result, the capacitor 18 has a potential at the terminal on the current output end side of the series rectifying element portion 17 in the capacitor 18 as a reference with the potential at the terminal on the current input end side of the series rectifying element portion 17 in the capacitor 18 as a reference. (With the same polarity as in the period T1) (charge is stored in the capacitor 18). In addition, as the current Ie flows through the inductor 9 in the period T2, the energy stored in the inductor 9 is released, so that the inductor 9 passes through the load LD, the diode 8b, and the diode 8a as shown in FIG. Then, the current Ic flows through the current path returning to the inductor 9 (the output DC voltage Vout is output to the load LD).

  Thus, in the period T3, the circuit on the second winding 2b side supplies the current Ic to the load LD (outputs the output DC voltage Vout) based on the energy released from the inductor 9, The operation of charging the capacitor 18 with the induced voltage V2 (energy from the second winding 2b) induced in the two windings 2b with the above polarity is executed as the third operation.

  Next, in the period T4, the circuit on the first winding 2a side is combined with the first winding 2a based on the energy released from the capacitor 7d and the energy from the input DC voltage Vin, similarly to the converter device 1A. The operation of supplying the current (If + Ig) and the operation of charging the capacitor 7c with the energy from the input DC voltage Vin are continuously executed. Accordingly, as shown in FIG. 14, an induced voltage V2 at which the second AC terminal portion 6b is at a higher potential than the second AC terminal portion 6a is continuously induced in the second winding 2b.

  In the circuit on the second winding 2b side, the switch 10a continues to be in the ON state. Therefore, as shown in FIG. 14, the induced voltage V2 induced in the second winding 2b has the same polarity as in the period T3. Based on this, the current Ih continues to flow from the second winding 2b to the second winding 2b via the diode 8a, the switch 10a in the ON state, the capacitor 18 and the diode 17b to charge the capacitor 18. Is continued. Further, when the switch 11a shifts from the OFF state to the ON state, a new current path from the capacitor 18 to the capacitor 18 through the ON state switch 10a, the inductor 9, the load LD, and the ON state switch 11a is formed. Is done. Thereby, based on the energy accumulated in the capacitor 18, the current Ij flows in the direction of the arrow in this new current path (the output DC voltage Vout is output to the load LD). Further, when the current Ij flows through the inductor 9, energy is accumulated in the inductor 9.

  In addition, since the currents Ih and Ij flow in opposite directions through the switch 10a where these two current paths overlap, a combined current (Ih−Ij) of the currents Ih and Ij flows.

  Thus, in the period T4, the circuit on the second winding 2b side continues the operation of charging the capacitor 18 with the induced voltage V2 (energy from the second winding 2b) induced in the second winding 2b. At the same time, based on the energy released from the capacitor 18, the current Ij is supplied to the load LD (output DC voltage Vout is output), and the operation of storing energy in the inductor 9 is executed as the fourth operation. Thereby, one cycle constituted by the period T1 to the period T4 is completed.

  Further, output DC voltage Vout in converter device 1B is expressed by the same equation as output DC voltage Vout in converter device 1A described above. Therefore, the converter device 1B functions as a Buck type (step-down type) converter in which the output DC voltage Vout is smaller than the input DC voltage Vin in the same manner as the converter device 1A, and each of the switches 7a, 7b, 10a, 11a. Controlling the output DC voltage Vout by changing the on-duty D of the switches 10a and 11a without changing the switching frequency (specifically, any voltage within the range up to zero volts) Can be controlled).

  Also in this converter device 1B, the circuit on the first winding 2a side includes the switching circuit unit 7 that converts the input DC voltage Vin into the AC voltage V1 and outputs the AC voltage V1 to the first AC terminal units 4a and 4b. In addition, the circuit on the second winding 2b side includes the second winding 2b, the second DC terminal portions 5a and 5b, the second AC terminal portions 6a and 6b, the series rectifying element portions 8 and 17, the inductor 9 and the switches. 10a and 11a are provided and connected as shown in FIG. The LC resonance circuit 12 is inserted and connected between the first winding 2a and the first AC terminal portions 4a and 4b.

  Therefore, since this converter device 1B is also configured as a one-stage type that does not require the step-down circuit that is essential in the two-stage converter described in the prior art, the switching that has occurred in the switch of this step-down circuit Loss can be eliminated. Further, according to this converter device 1B, the switches 10a and 11a constituting the circuit on the second winding 2b side are driven so that the soft switching operation can be achieved by the drive signals S1 and S2 supplied from the control unit 13. Therefore, it is possible to reduce the loss of the converter device 1B as a whole. Also in the converter device 1B, the switches 10a and 11b constituting the circuit on the second winding 2b side are driven by the drive signals S1 and S2 supplied from the control unit 13, whereby the second winding 2b. The circuit on the side performs the first to fourth operations in each of the periods T1, T2, T3, and T4, so that the switching frequency of each switch 7a, 7b, 10a, 11a is not changed (while being constant) ), The output DC voltage Vout can be controlled by changing the on-duty of the switches 10a and 11a (specifically, it can be controlled to any voltage within the range up to zero volts). As a result, it is possible to easily perform the output voltage control at the time of overcurrent while solving the problem in the converter device configured to control the output DC voltage Vout by changing the switching frequency. It can be avoided. Furthermore, according to this converter device 1B, a capacitor for forming a circuit on the second winding 2b side (an electronic component whose outer shape is usually very large compared to the switch 10a formed of a semiconductor element or the like) Therefore, the circuit board on which the electronic components are mounted and the device itself can be downsized compared to the converter device 1A that requires two capacitors 10b and 11b. .

  In the converter devices 1A and 1B, the LC resonant circuit 12 is configured by the resonant capacitor 12a and the resonant inductor 12b as independent components. However, the present invention is not limited to this. For example, the resonant capacitor 12a is replaced with a configuration (capacitor 7c or capacitor 7d) included in the switching circuit units 7 and 16 or a capacitor 10b of the first series circuit unit 10 instead of the configuration arranged as an independent component. Alternatively, the capacitor 11b of the second series circuit unit 11 can be substituted. In addition, the resonance inductor 12b can be replaced with the leakage inductance of the transformer 2 in place of the configuration provided as an independent component.

1A, 1B converter device
2 transformer 2a first winding 2b second winding 3a, 3b first DC terminal 4a, 4b first AC terminal 5a, 5b second DC terminal 6a, 6b second AC terminal
7 Switching circuit
8,17 Series rectifier element
9 Inductor 10 First Series Circuit 10a Switch (First Switch)
10b Capacitor (first capacitor)
11 2nd series circuit part 11a Switch (2nd switch)
11b capacitor (second capacitor)
12 LC resonance circuit 13 Control part L1a, L1b 1st connection line L2a, L2b 2nd connection line Lp1 1st power line Lp1 2nd power line

Claims (4)

A transformer in which a first winding and a second winding are formed;
A pair of first DC terminal portions;
A pair of first AC terminal portions connected to the first winding via a pair of first connection lines;
A pair of second DC terminal portions;
A pair of second AC terminal portions connected to the second winding via a pair of second connection lines;
The pair of first DC terminal portions and the pair of first AC terminal portions are disposed between the pair of first DC terminal portions, and input DC voltages input to the pair of first DC terminal portions are converted into AC voltages to convert the pair. A switching circuit unit that outputs to the first AC terminal unit;
The first rectifying element and the second rectifying element are connected in series with the forward direction aligned and connected to one second AC terminal part of the pair of second AC terminal parts. The current output end is connected to one second DC terminal portion of the pair of second DC terminal portions via the first power line, and the current input end portion is connected to the pair via the second power line. A series rectifying element connected to the other second DC terminal of the second DC terminals,
An inductor inserted and connected to at least one of the first power line and the second power line;
A first switch and a first capacitor connected in series, one end of which is connected to the current output end of the series rectifying element unit and the other end of the pair of second AC terminal units A first series circuit portion connected to the other second AC terminal portion,
It is composed of a second switch and a second capacitor connected in series, and one end is connected to the other second AC terminal and the other end is the current input end of the series rectifying element unit. A second series circuit portion connected to
An LC resonant circuit inserted and connected to at least one of the pair of first connection lines and the pair of second connection lines;
A control unit that converts the input DC voltage into an output DC voltage by performing switching control on the switching circuit unit, the first switch, and the second switch, and outputs the output DC voltage between the pair of second DC terminal units; A converter device comprising: The control unit performs the switching control,
An induced voltage at which the other second AC terminal portion becomes a high potential is generated in the second winding with respect to the one second AC terminal portion, the first switch is turned off, and the first switch The first operation of causing the second switch to turn on and storing energy in the second capacitor based on the induced voltage and outputting the output DC voltage by discharging energy stored in the inductor. ,
An induced voltage at which the other second AC terminal portion becomes a high potential is generated in the second winding with respect to the one second AC terminal portion, and the first switch and the second switch are turned on. To cause the second capacitor to store energy based on the induced voltage, to release the energy stored in the first capacitor, to output the output DC voltage, and to cause the inductor to store energy. A second action to accumulate,
An induced voltage at which the one second AC terminal portion becomes a high potential is generated in the second winding with respect to the other second AC terminal portion, the first switch is turned on, and the first switch 2. A third operation in which the switch is turned off to store energy in the first capacitor based on the induced voltage and to output the output DC voltage by discharging energy stored in the inductor. ,
In addition, an induced voltage in which the one second AC terminal portion becomes a high potential is generated in the second winding with respect to the other second AC terminal portion, and the first switch and the second switch are turned on. To cause the first capacitor to store energy based on the induced voltage, to release the energy stored in the second capacitor, to output the output DC voltage, and to cause the inductor to store energy. The converter device according to claim 1, wherein the switching circuit unit, the first series circuit unit, and the second series circuit unit are repeatedly caused to execute the fourth operation for storing the voltage. A transformer in which a first winding and a second winding are formed;
A pair of first DC terminal portions;
A pair of first AC terminal portions connected to the first winding via a pair of first connection lines;
A pair of second DC terminal portions;
A pair of second AC terminal portions connected to the second winding via a pair of second connection lines;
The pair of first DC terminal portions and the pair of first AC terminal portions are disposed between the pair of first DC terminal portions, and input DC voltages input to the pair of first DC terminal portions are converted into AC voltages to convert the pair. A switching circuit unit that outputs to the first AC terminal unit;
The first rectifying element and the second rectifying element are connected in series with the forward direction aligned and connected to one second AC terminal part of the pair of second AC terminal parts. The current output end is connected to one second DC terminal portion of the pair of second DC terminal portions via the first power line, and the current input end portion is connected to the pair via the second power line. A first series rectifying element connected to the other second DC terminal of the second DC terminals,
An inductor inserted and connected to at least one of the first power line and the second power line;
The third rectifying element and the fourth rectifying element are connected in series with the forward direction aligned and connected to the other second AC terminal part of the pair of second AC terminal parts. A second series rectifier element portion;
A first switch connected between the current output end of the first series rectifier element and the current output end of the second series rectifier element;
A second switch connected between the current input end of the first series rectifier element and the current input end of the second series rectifier element;
A capacitor connected in parallel to the second series rectifying element unit;
An LC resonant circuit inserted and connected to at least one of the pair of first connection lines and the pair of second connection lines;
A control unit that converts the input DC voltage into an output DC voltage by performing switching control on the switching circuit unit, the first switch, and the second switch, and outputs the output DC voltage between the pair of second DC terminal units; A converter device comprising: The control unit performs the switching control,
An induced voltage at which the other second AC terminal portion becomes a high potential is generated in the second winding with respect to the one second AC terminal portion, the first switch is turned off, and the first switch A first operation for causing the capacitor to accumulate energy based on the induced voltage by turning on the two switches and outputting the output DC voltage by releasing the energy accumulated in the inductor;
An induced voltage at which the other second AC terminal portion becomes a high potential is generated in the second winding with respect to the one second AC terminal portion, and the first switch and the second switch are turned on. To cause the capacitor to store energy based on the induced voltage, to discharge the energy stored in the capacitor, to output the output DC voltage, and to store energy in the inductor. Operation,
An induced voltage at which the one second AC terminal portion becomes a high potential is generated in the second winding with respect to the other second AC terminal portion, the first switch is turned on, and the first switch A third operation for causing the capacitor to accumulate energy based on the induced voltage by turning off the two switches and outputting the output DC voltage by discharging the energy accumulated in the inductor;
In addition, an induced voltage in which the one second AC terminal portion becomes a high potential is generated in the second winding with respect to the other second AC terminal portion, and the first switch and the second switch are turned on. To cause the capacitor to store energy based on the induced voltage, to release the energy stored in the capacitor, to output the output DC voltage, and to store energy in the inductor. The converter device according to claim 3, wherein the four operations are repeatedly executed by the switching circuit unit, the first switch, and the second switch.

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