JP6846082B2 - Bidirectional power supply - Google Patents

Description

The present invention can output an AC voltage to the other terminal based on the DC voltage received by one terminal and output a DC voltage to one terminal based on the AC voltage received by the other terminal. Regarding power supply device.

There is an increasing need to charge vehicle batteries based on commercial AC power sources, such as in the case of electric vehicles. In addition, there may be cases where you want to use a home appliance that operates on an AC power source outdoors, such as when you go outdoors in a car.

Therefore, a power supply device that realizes the above-mentioned operation with one power supply device is desired.

Japanese Unexamined Patent Publication No. 2001-037226 Japanese Unexamined Patent Publication No. 2008-206304 Japanese Unexamined Patent Publication No. 2009-261186 Japanese Unexamined Patent Publication No. 2011-155837 Japanese Unexamined Patent Publication No. 2012-110108 Japanese Unexamined Patent Publication No. 2013-062936 Japanese Unexamined Patent Publication No. 2013-070463 Japanese Unexamined Patent Publication No. 2013-258883 Japanese Unexamined Patent Publication No. 2014-007904 Japanese Unexamined Patent Publication No. 2014-230368 Japanese Unexamined Patent Publication No. 2014-230371 JP 2015-100198

Here, a configuration that realizes bidirectional operation by utilizing a body diode of a power MOSFET is well known (Patent Documents 1 to 12). However, it cannot be said that the degree of perfection is high in mounting any of the configurations in an automobile and driving a home electric appliance in the field.

For example, in the inventions described in Patent Document 2 and Patent Document 9, an AC voltage is generated by DC / AC conversion (inverter operation) + rectification operation + inverter operation, and a DC voltage is generated by AC / DC conversion + inverter operation + rectification operation. It is only generated, and it cannot be said that it has a high degree of perfection in terms of performance and others.

The present invention has been completed based on the above circumstances, and an object of the present invention is to provide a bidirectional power supply device having a higher degree of perfection.

In order to achieve the above object, the present invention presents a high frequency transformer (TRN) having a switching element in which an energizing element capable of passing an energizing current in the direction opposite to the ON current is connected in parallel and a center tap on one side and the other side. A computer circuit (MICOM) that receives an operation instruction, and a first and second operation control circuits (CTL1 and CTL2) that are controlled by the computer circuit and function in two modes. A bidirectional power supply device capable of bidirectional conversion operation of DC voltage and AC voltage between (T1, T2) and the device connection terminals (T3, T4) on the other side, each of which is a first contact. The first relay circuit (REL1) and the second relay circuit (REL2) having the second contact and the output terminal are connected directly or via other circuit elements, and the center on the other side of the high-voltage transformer (TRN). The tap is connected to the second contact of the second relay circuit directly or via another circuit element, and the upper terminal on the other side of the high frequency transformer (TRN) is connected to the first rectifying element via at least the first rectifying element. The first contact of the one relay circuit is connected, and the lower terminal on the other side of the high-frequency transformer (TRN) is connected to the first contact of the first relay circuit via at least the second rectifying element.

Further, the present invention receives an operation instruction from a switching element in which an energizing element capable of passing an energizing current in the direction opposite to the ON current is connected in parallel, and a high-frequency transformer (TRN) having center taps on one side and the other side. It has a computer circuit (MICOM) and first and second operation control circuits (CTL1, CTL2) that are controlled by the computer circuit and function in two modes, and has a device connection terminal (T1, T2) on one side. A bidirectional power supply device capable of bidirectional conversion operation of DC voltage and AC voltage between the device connection terminals (T3 and T4) on the other side, which are the first contact, the second contact, and the second contact, respectively. The first relay circuit (REL1) having an output terminal and the second relay circuit (REL2) are connected directly or via another circuit element, and the center tap on the other side of the high-voltage transformer is directly or another circuit element. It is connected to the first contact of the first relay circuit via the above, and the second contact of the second relay circuit is connected directly or via another circuit element.

The present invention has a high-frequency transformer having center taps on one side and the other side, and a first relay circuit, and a circuit configuration centered on these can realize a highly complete bidirectional power supply device. ..

It is a circuit diagram which shows the whole structure of the bidirectional power supply device which concerns on 1st Example. It is a drawing explaining the operation which outputs the AC voltage to the other side terminal based on the DC voltage received by one side terminal. It is a drawing explaining the operation which outputs the DC voltage to one side terminal based on the AC voltage received by the other side terminal. It is a drawing which outlines the circuit structure of the power factor improvement circuit. It is a drawing explaining the circuit operation of the specific power factor improvement circuit. It is a waveform diagram explaining the internal operation of a power factor improvement circuit. It is a drawing explaining the modification embodiment about a relay circuit. It is a circuit diagram which shows the whole structure of the bidirectional power supply device which concerns on 2nd Example. It is a drawing explaining the operation which outputs the AC voltage to the other side terminal based on the DC voltage received by one side terminal. It is a drawing explaining the operation which outputs the DC voltage to one side terminal based on the AC voltage received by the other side terminal.

Hereinafter, the present invention will be described in more detail based on the first embodiment. FIG. 1 is a circuit diagram showing the overall configuration of the bidirectional power supply device EQU, in which a high-frequency transformer TRN is arranged between the one-side terminals T1 and T2 and the other-side terminals T3 and T4, and the ground lines GND1 and GND2 are arranged. It is configured by incorporating a distinct left circuit LEFT and a right circuit RIGHT.

As shown in the figure, the one-side terminal T2 is connected to the frame ground GND1 which is the first ground. In the present specification, also for the high frequency transformer TRN, the left side in the drawing is referred to as one side, and the right side in the drawing is referred to as the other side.

In this embodiment, the one-side terminals T1 and T2 are terminals related to the DC voltage DC, and the other-side terminals T3 and T4 are terminals related to the AC voltage AC. The high-frequency transformer TRN is configured to have center taps on one side winding and the other side winding, respectively. The one-side winding is divided by the center tap to form the coil L1 and the coil L2, and the other side winding is divided by the center tap to form the coil L2 and the coil L3.

The left circuit LEFT includes a first capacitor C1 arranged between the one-side terminal T1 and the first ground GND1, a choke coil L7 arranged between the one-side terminal T1 and the center tap of the high-frequency transformer TRN, and a coil L1. To the MOSFET (Q1) arranged between the upper terminal and the first ground GND1, the MOSFET (Q2) arranged between the lower terminal of the coil L2 and the first ground GND1, and the one-side terminal T2. It is configured to include a current detection resistor R1 for detecting a return current and a general-purpose microcomputer MICON for controlling each part of the device. In this specification, the terms upper terminal and lower terminal are used for convenience, but both of them mean terminals on the non-center tap side.

The MOSFETs (metal-oxide-semiconductor field-effect transistor) Q1 and Q2 (hereinafter abbreviated as transistors Q1 and Q2) of the embodiment are N-channel MOSFETs, and body diodes Db1 and Db2 are inserted between the source and drain thereof. Equivalently built-in. This point is the same for the other transistors (MOSFETs) Q3 to Q8, and the body diodes Db3 to Db8 are equivalently built in, respectively.

The microcomputer MICOM receives an operation mode instruction (operation instruction) via the operation input unit SET, and controls the right circuit RIGHT via interface circuits IF2 and IF3 such as a photocoupler. Specifically, the first control circuit CTL1 and the second control circuit CTL2 are controlled via the interface circuit IF2, and the relay circuits REL1 and REL2 are controlled via the interface circuit IF3.

As shown in the figure, the voltage across the current detection resistor R1 is supplied to the microcomputer MICOM, and the microcomputer MICOM controls each gate voltage of the pair of transistors Q1 and Q2. Further, the DC voltage level LV of the one-side terminal T1 is supplied to the adder circuit via the interface circuit IF1 such as a photocoupler. As shown in the figure, the differential voltage VRQ output by the microcomputer MICOM is also supplied to the adder circuit, and the output (VRQ + LV) of the adder circuit is supplied to the first control circuit CTL1.

The right-hand circuit RIGHT includes a first control circuit CTL1 that is controlled by a microcomputer MICON and can function as a PFC (Power Factor Correction) controller, and a second control circuit CTL2 that is controlled by a microcomputer MICON and can function as an inverter controller. , The first relay circuit REL1 and the second relay circuit REL2, and the transistors (N-channel MOSFETs) Q3 to Q8 are mainly configured.

As shown in the figure, the first relay circuit REL1 and the second relay circuit REL2 are connected in series between the other windings L3 and L4 of the high-frequency transformer TRN and the center tap, respectively, by different paths. That is, a first series circuit is formed in the path of the second contact of the coil L3 (upper terminal) → diode D2 → first relay circuit REL1 and second relay circuit REL2 → second relay circuit REL2, and the coil L4 (lower side). A second series circuit is formed by the path of the second contact of the terminal) → diode D1 → first relay circuit REL1 and second relay circuit REL2 → second relay circuit REL2.

Further, a transistor Q3 is arranged between the lower terminal of the coil L4 and the second ground GND2, and a transistor Q4 is arranged between the upper terminal of the coil L3 and the second ground GND2. .. As shown in the figure, the diode D1 and the transistor Q3, and the diode D2 and the transistor Q4 are connected to the anode terminal of the diode and the drain terminal of the transistor, respectively.

The first relay circuit REL1 and the second relay circuit REL2 are configured to have an upper first contact, a lower second contact, and an output terminal OT, and are controlled by a microcomputer MICON, whichever is used. The contact and the output terminal OT are configured to be connected. Further, a second capacitor C2 is connected between the output terminal OT of the first relay circuit REL1 and the second ground GND2.

A choke coil L6 is connected to the output terminal OT of the second relay circuit REL2, and four transistors Q5 to Q8 are arranged in a full bridge type at one terminal Hv of the choke coil L6. That is, the transistors Q5 and Q6 are connected in series, the transistors Q7 and Q8 are connected in series, and the drain terminals of the transistors Q5 and Q7 are commonly connected to one terminal Hv of the choke coil L6.

Further, the source terminals of the transistors Q6 and Q8 are connected to each other, and the current detection resistor R2 is arranged between the connection point and the second ground. Further, a common mode choke coil COMMON is arranged between the source terminals Q5S and Q7S of the transistors Q5 and Q7 and the other side terminals T3 and T4.

Here, the common mode choke coil COMMON refers to a choke coil in which the winding directions of the two coil windings wound around the magnetic core are opposite to each other. Therefore, the noise current in the common mode flows in each winding and the direction of the magnetic flux generated by each noise current is in the same direction, and the counter electromotive force generated in each winding is strengthened, which has the effect of suppressing the noise current. Is realized.

As shown in the figure, the first control circuit CTL1 controls the gate voltage of the transistors Q3 and Q4, and receives the voltage across the current detection resistor R2 and the voltage of one terminal Hv of the choke coil L6.

As described above, the first control circuit CTL1 is connected to the interface circuits IF1 and IF2, and the DC voltage level LV of the one-side terminal T1 is grasped via the interface circuit IF1 and the interface is detected. The differential voltage VRQ and the binary ON / OFF command are received from the microcomputer MICOM via the circuit IF2.

When the first control circuit CTL1 receives an ON command, it functions as a PFC controller and is the sum (LV + VRQ) of the DC voltage level (DC output voltage) LV of one terminal T1 and the differential voltage VRQ. However, the gate voltage of the transistors Q3 and Q4 is PWM-controlled so as to match the specified target voltage Vt (for example, 16V).

Therefore, the DC output voltage LV output from the one-side terminals T1 and T2 corresponds to the difference voltage VRQ received from the microcomputer MICOM and is based on the PWM control of the first control circuit CTL1. (This point will be described later with reference to FIG. 5).

On the other hand, the second control circuit CTL2 receives an ON / OFF command from the microcomputer MICOM via the interface circuit IF2. Then, when the second control circuit CTL2 receives an ON command, it functions as an inverter controller and controls ON / OFF of the gate voltages Q5G to Q8G of the transistors Q5 to Q8.

Since the circuit configuration has been described above, next, when the microcomputer MICOM receives an operation instruction to output an AC voltage to the other terminals T3 and T4 based on the DC voltage received by the one side terminals T1 and T2. The operation will be described.

FIG. 2 illustrates this operating state, and the microcomputer MICOM controls the upper first contact and the output terminal OT of the first relay circuit REL1 and the second relay circuit REL2, respectively, in a connected state. There is. Further, the microcomputer MICOM issues an OFF command to the first control circuit CTL1 while issuing an ON command to the second control circuit CTL2.

Therefore, the first control circuit CTL1 that has received the OFF command keeps the transistors Q3 and Q4 in the non-operating state by setting the gate voltage of the transistors Q3 and Q4 to the L level. On the other hand, the second control circuit CTL2 that has received the ON command functions as an inverter controller.

In this state, the microcomputer MICOM complementaryly controls ON / OFF of the transistors Q1 and Q2 as shown in FIG. 2A. Therefore, in the operating state where the transistor Q1 is ON and the transistor Q2 is OFF, the ON current of the transistor Q1 flows through the path shown by the broken line, and on the other side of the high frequency transformer TRN, the diode D1 → the first relay circuit REL1 → the second capacitor. The coil current (L3, L4) in the direction of C2 → body diode Db4 flows in an increasing tendency.

After that, when the transistor Q1 is turned off and the transistor Q2 is turned off, the coil current in the same path continues to decrease based on the induced voltage on the other side of the high-frequency transformer TRN.

Next, since the transistor Q1 is turned off and the transistor Q2 is turned on, the ON current of the transistor Q2 flows along the solid line path shown in the figure, and the diode D2 → the first on the other side of the high frequency transformer TRN. The coil current (L3, L4) in the direction of the relay circuit REL1 → the second capacitor C2 → the body diode Db3 flows in an increasing tendency.

By repeating the increase and decrease of the coil current (L3 and L4) in this way, the voltage across the second capacitor C2 becomes a DC voltage including a slight ripple. As described above, in this embodiment, the push-pull DC / DC converter is realized by the circuit configuration from the one-side terminals T1 and T2 to the second relay circuit REL2. In order to suppress the decrease in the coil current, as shown in the rectangular frame of FIG. 7A, between the first relay circuit REL1 and the second relay circuit REL2, or between the diodes D1 and D2 and the first relay circuit. It is also preferable to additionally arrange the choke coil L2 between the relay 1 and the choke coil L2.

Further, as shown in the rectangular frames of FIGS. 7 (b) to 7 (d), by adding an appropriate number of choke coils L1 / L2 / L3, the operation in the right direction shown in FIG. 2 and the operation in the right direction shown in FIG. The optimum inductance value can be set according to the operation in the left direction shown.

For example, as a push-pull DC / DC converter (shown rightward operation) centered on transistors Q1 and Q2, the circuit configuration of FIG. 7 (c) is the same as that of FIG. 7 (a), and the coil current is smoothed. The choke coil L2 + L6 of the optimum value for this purpose and the choke coil L1 are selected.

On the other hand, as the power factor improving operation (leftward operation shown in FIG. 3) centered on the transistors Q3 and Q4, the circuit configurations of FIGS. 7 (a) and 7 (d) are the same as those of FIG. 2, and the optimum values are obtained. The choke coil L6 or L3 of is selected. Further, as the power factor improving operation (shown leftward operation), the circuit configurations of FIGS. 7 (b) and 7 (c) are the same, and the choke coil L1 and the choke coil L3 having the optimum values are selected.

In any case, in the circuit configurations of FIGS. 1 and 7 (a) to 7 (c), the DC voltage of the second capacitor C2 is supplied to the transistors Q5 to Q8 via the choke coils L6 / L1. .. At this time, the second control circuit functions as an inverter controller, and the gate voltages Q5G to Q8G of each transistor Q5 to Q8 are controlled by PWM control or simple ON / OFF control to AC from the other side terminals T3 and T4. The voltage AC is output. That is, each transistor Q5 to Q8 functions as a full bridge type inverter circuit.

Subsequently, the operation when the microcomputer MICOM receives an operation instruction to output a DC voltage to the one-side terminals T1 and T2 based on the AC voltage received by the other-side terminals T3 and T4 will be described.

FIG. 3 illustrates this operating state. The microcomputer MICOM controls the transistors Q1 and Q2 to be OFF, and the first relay circuit REL1 and the second relay circuit REL2 are respectively connected to the lower second contact. The output terminal OT is controlled to be connected. Further, the microcomputer MICOM issues an ON command to the first control circuit, and an OFF command to the second control circuit.

Therefore, the second control circuit CTL1 that has received the OFF command keeps the transistors Q5 to Q8 in the non-operating state by setting the gate voltage of the transistors Q5 to Q8 to the L level. As a result, the body diodes Db5 to Db8 form a bridge-type full-wave rectifier circuit, and a rectified voltage is obtained at the Hv terminal.

On the other hand, the first control circuit CTL1 that has received the ON command functions as a PFC controller. FIG. 4 schematically shows an operating state at this time, that is, an operating state of the power factor improving circuit. Further, FIG. 5A shows, as an example of a specific PFC controller, UCC2817A (TEXAS INSTRUMENTS), which controls the phase of the AC line current to match the phase of the AC line voltage and realizes a power factor of 1. Shows the internal configuration of.

As shown in FIG. 5A, this PFC controller has an under voltage lock out (UVLO) function to prevent malfunction when the power is turned on, and the power supply voltage is abnormal during operation. Even if it drops, the internal circuit is placed in a quasi-standby state to prevent malfunction.

Further, by utilizing the PKLMT (peak current limit) terminal and the OVP / EN (overvoltage / enable) terminal, the overvoltage overcurrent protection function and the high-precision reference circuit enable function are exhibited.

Further, a sense voltage Vs (= Vt * Rb / (Ra + Rb)) obtained by dividing the target voltage Vt (= LV + VRQ) by the voltage dividing resistors Ra and Rb is supplied to the inverting input terminal VSENSE of the voltage error amplifier. .. In the case of the embodiment, a reference voltage of 7.5 V is supplied to the voltage error amplifier, and the PFC controller operates so that the sense voltage Vs matches the reference voltage of 7.5 V.

Although not particularly limited, in this embodiment, the voltage dividing resistors Ra and Rb are set so that the target voltage Vt becomes Vt = 16V, and the actual DC output voltage LV is LV = Vt-VRQ = 16-VRQ. It becomes. That is, in this embodiment, the larger the differential voltage VRQ output by the microcomputer MICOM, the lower the actual DC output voltage LV (LV ≦ 16V).

As shown in FIG. 4A, the power factor improving circuit of the first embodiment conceptually includes a PFC controller PFC, a choke coil L6, transistors Q3 and Q4, a current detection resistor R2, and a resistor R2. It has a current detection unit DT1, a rectification voltage Hv detection unit DT2, diodes Db1 and Db21, a smoothing circuit using a choke coil L7 and a capacitor C1, an interface circuit IF1 for detecting an output voltage, and a high-frequency transformer TRN. As shown in FIG. 4 (b), the current continuous mode is operated.

PFC controller The PFC includes a current detector (IL Dect), a multiplier, a sawtooth wave generator (Saw tooth OSC) with a switching frequency of Fs (several tens of kHz), and a comparator (PWM Com) that outputs PWM waves. ) And the driver unit Dr. Then, the PWM wave of the switching frequency Fs is output based on the rectified voltage specified by the detection unit DT2, the energizing current specified by the detection unit DT1, and the output voltage specified by the interface circuit IF1. ..

As a result, the transistors Q3 and Q4 operate ON / OFF with an appropriate conduction time, and the ON current of the transistors Q3 and Q4 is smoothed by the choke coil L6, so that the power factor shown in FIG. 4B is formed. The coil current has a power factor improved to = 1.

FIG. 5 shows a circuit diagram when UCC2817A (TEXAS INSTRUMENTS) is used as the PFC controller, and the DRVOUT signal (gate drive signal) of the PFC controller is a D-type flip-flop FF that performs a toggle operation and an OR. The gate control voltages Q3G and Q4G of the transistors Q3 and Q4 pass through the gates G1 and G2 and the drivers Dr and Dr.

5 (b) and 5 (c) are time charts for the circuit configuration of FIG. 5 (a), and a case where the DRVOUT signal of the PFC controller is supplied to the clock terminal CLK of the D-type flip-flop FF. The waveform of each part is shown.

The DRVOUT signal output from the PFC controller is a PWM wave having a pulse period T, and FIG. 5 (b) shows FIG. 5 (b) when the duty ratio (τ) of the DRVOUT signal is τ <50%. The case where the duty ratio (τ) of the DRVOUT signal is τ> 50% is shown.

The lip flop FF that receives such a DRVOUT signal at the clock terminal realizes a toggle operation that inverts the Q output and the Q bar output at the rising edge of the DRVOUT signal. Therefore, the pulse widths of the Q output and the Q bar output of the flip-flop FF coincide with the pulse period T.

Then, in this embodiment, the Q output of the pulse width T and the DRVOUT signal are supplied to the OR gate G1 to generate the gate control voltage Q3G of the transistor Q3, and the Q bar output of the pulse width T and the DRVOUT signal are used. Is supplied to the OR gate G2 to generate the gate control voltage Q4G of the transistor Q4.

Therefore, the pulse widths of the gate control voltage Q3G and the gate control voltage Q4G widen corresponding to the duty ratio (τ) of the DRVOUT signal, and the two transistors Q3 and Q4 as shown by the diagonal lines are both ON. There will be overlapping ON periods of operation.

Then, this overlapping ON period extends corresponding to the duty ratio (τ) of the DRVOUT signal, and as shown in FIGS. 5 (b) and 5 (c), the ON period of the DRVOUT signal coincides with the overlapping ON period. .. That is, in this embodiment, the overlapping ON period of the two transistors Q3 and Q4 is extended corresponding to the duty ratio (τ) of the DRVOUT signal, and the two transistors Q3 and Q4 are both turned off. There is no period.

Based on the above, the description will be continued based on FIG. In the overlapping ON period, the other side winding L4 of the high frequency transformer is in the path of the choke coil L6 → coil L4 → transistor Q3 based on the rectified voltage Hv, corresponding to the ON operation of the two transistors Q3 and Q4. Along with the coil current I4 flowing (see the solid line), the coil current I3 of the other winding L3 of the high frequency transformer flows along the path of the choke coil L6 → the coil L3 → the transistor Q4 (see the broken line).

In the transformer core of the high-frequency transformer TRN, the magnetic flux generated by the coil currents I3 and I4 of the coils L3 and L4 reverses and cancels each other. Therefore, during this period, the high-frequency transformer TRN does not function as a transformer, and the choke coil L6 The left end is in a state of being grounded by the transistors Q3 and Q4, and one end of the coil in a general PFC circuit is in a state of being grounded.

After that, when either the transistor Q3 or the transistor Q4 makes an OFF transition, the rectified voltage Hv and the potential difference across L6 due to the energy stored in the choke coil L6 are added to the center tap on the other side (right side) of the transformer. The applied voltage is applied.

When the transistor Q3 is OFF, a current flows in the path of the choke coil L6 → the coil L3 → the transistor Q4, and the capacitor charging current flows in the path of the coil L1 → the choke coil L7 → the capacitor C1 → the diode Db1.

On the other hand, when the transistor Q4 is OFF, a current flows in the path of the choke coil L6 → the coil L4 → the transistor Q3, and the capacitor charging current flows in the path of the coil L2 → the choke coil L7 → the capacitor C1 → the diode Db2.

Although not shown, a snubber circuit is connected in parallel to the transistors Q3 and Q4, and the stored energy of the coil L4 after the OFF transition of the transistor Q3 and the coil after the OFF transition of the transistor Q4. The stored energy of L3 is appropriately discharged.

As described above, in this embodiment, the left end of the choke coil L6 can be ground-faulted during the period when both the transistors Q3 and Q4 are ON, and the PFC operation can be performed by controlling the period with the PFC control circuit. Moreover, it is possible to realize a DC power supply capable of operating as a push-pull converter during a period in which one of the transistors Q3 and Q4 is ON and the other is OFF.

The examples of driving the transistors Q3 and Q4 based on the PWM waves of FIGS. 5 (b) and 5 (c) have been described above. FIG. 6 shows the waveforms of each part, and shows the AC input voltage AC (a) and the Hv terminal voltage (b) received by the other side terminals T3 and T4, the gate control voltage Q3G (c) of the transistor Q3, and the transistor. The relationship between the gate control voltage Q4G (d) of Q4 and the DC voltage LV (e) output from the terminals T1 and T2 on one side is shown.

Although the first embodiment of the present invention has been specifically described above, the specific description contents are not particularly limited to the present invention. That is, in the first embodiment of FIG. 1, the diodes D1 and D2 are provided, but these may be omitted.

FIG. 8 shows the circuit configuration of the second embodiment in which the diodes D1 and D2 are omitted. The center tap of the high frequency transformer TRN is connected to the first contact on the upper side of the first relay circuit REL1 and is passed through the choke coil L6. , It is connected to the second contact on the lower side of the second relay circuit REL2.

Then, a choke coil L5 is connected between the output terminal OT of the first relay circuit REL1 and the first contact on the upper side of the second relay circuit REL2, and the first contact and the second contact on the upper side of the second relay circuit REL2 are connected. A second capacitor C2 is arranged between the ground GND2 and the ground GND2.

The circuit between the center tap of the high-frequency transformer TRN and the Hv terminal is not limited to the circuit configuration shown in the figure, and is rectangular in FIGS. 1, 7 (a), 7 (b), and 7 (c). The circuit configuration shown in the frame may be used.

In any case, the circuit operation is the same as that of the circuit of FIG. 1, and the microcomputer MICOM outputs an AC voltage to the other side terminals T3 and T4 based on the DC voltage received by the one side terminals T1 and T2. When the operation instruction to be performed is received, the operation shown in FIG. 9 is executed.

The circuit operation shown in FIG. 9 is the same as in the case of FIG. 2, and the microcomputer MICOM connects the upper first contact and the output terminal OT of the first relay circuit REL1 and the second relay circuit REL2, respectively. I'm in control. Further, the microcomputer MICOM issues an OFF command to the first control circuit CTL1 while issuing an ON command to the second control circuit CTL2.

As a result, the first control circuit CTL1 that receives the OFF command keeps the transistors Q3 and Q4 in the non-operating state. On the other hand, the second control circuit CTL2 that has received the ON command functions as an inverter controller.

In this state, the microcomputer MICOM complementaryly controls ON / OFF of the transistors Q1 and Q2 as shown in FIG. 2A. Therefore, in the operating state where the transistor Q1 is ON and the transistor Q2 is OFF, the ON current of the transistor Q1 flows through the path shown by the broken line, and on the other side of the high frequency transformer TRN, the lower terminal of the coil L3 → the first relay circuit REL1. → Choke coil L5 → Second capacitor C2 → Coil current of coil L3 in the direction of body diode Db4 flows in an increasing tendency.

After that, when the transistor Q1 is turned off and the transistor Q2 is turned off, the coil current in the same path continues to decrease based on the induced voltage on the other side of the high-frequency transformer TRN.

Next, since the transistor Q1 is turned off and the transistor Q2 is turned on, the ON current of the transistor Q2 flows along the solid line path shown in the figure, and the upper terminal of the coil L4 is on the other side of the high frequency transformer TRN. → 1st relay circuit REL1 → Choke coil L5 → 2nd capacitor C2 → The coil current of the coil L4 in the direction of the body diode Db3 flows in an increasing tendency.

By repeating the increase and decrease of the coil current (L3 and L4) in this way, the voltage across the second capacitor C2 becomes a DC voltage including a slight ripple. The point that the push-pull DC / DC converter is realized by the circuit configuration from the one-side terminals T1 and T2 to the second relay circuit REL2 is the same as in the case of FIG.

However, in the circuit configuration of FIG. 9, since the second capacitor C2 is only charged based on the induced voltage of either the coil L3 or the coil L4, it is charged based on the induced voltage of the coils L3 + L4. The voltage across the second capacitor C2 is lower than in the case of. Therefore, the turns ratio between one side and the other side of the high-frequency transformer is a turn ratio based on this fact.

Subsequently, the operation when the microcomputer MICOM receives an operation instruction to output a DC voltage to the one-side terminals T1 and T2 based on the AC voltage received by the other-side terminals T3 and T4 will be described.

FIG. 10 illustrates this operating state. The microcomputer MICOM controls the transistors Q1 and Q2 to be OFF, and the first relay circuit REL1 and the second relay circuit REL2 are respectively connected to the lower second contact. The output terminal OT is controlled to be connected. Further, the microcomputer MICOM issues an ON command to the first control circuit, and an OFF command to the second control circuit.

Therefore, the second control circuit CTL1 that has received the OFF command keeps the transistors Q5 to Q8 in the non-operating state by setting the gate voltage of the transistors Q5 to Q8 to the L level. As a result, the body diodes Db5 to Db8 form a bridge-type full-wave rectifier circuit, and a rectified voltage is obtained at the Hv terminal.

Further, as shown in FIGS. 5 (b) and 5 (c), the transistors Q3 and Q4 have an overlapping ON period and operate in ON, so that the capacitor C1 passes through the coils L1 + L2 and the choke coil L7. It will be charged, and a DC power supply with a large current capacity will be realized.

Although the first embodiment and the second embodiment of the present invention have been described in detail above, the specific circuit configuration is not particularly limited to the present invention and can be appropriately changed. For example, in the above embodiment, the DC voltage level LV of the one-side terminal T1 is supplied to the adder circuit, and the adder voltage (VRQ + LV) is supplied to the first control circuit CTL1, but the present invention is not limited to this.

That is, the subtraction voltage (LV-VRQ) can be supplied to the first control circuit CTL1 by providing the subtraction circuit instead of the adder circuit. In this case, the larger the differential voltage VRQ, the higher the actual DC output voltage LV.

TRN high frequency transformer Q1 to Q8 switching element D1, D2 rectifier element T1, T2 One side device connection terminal T3, T4 Other side device connection terminal MICON computer circuit CTL1 1st operation control circuit CTL2 2nd operation control circuit REL1 1st relay Circuit REL2 2nd relay circuit

Claims (4)

A switching element in which energizing elements that can pass an energizing current in the opposite direction to the ON current are connected in parallel, a high-voltage transformer (TRN) that has center taps on one side and the other side, and a computer circuit (MICOM) that receives operation instructions. , A first and second operation control circuits (CTL1, CTL2) that are controlled by a computer circuit and function in two modes, one side of the device connection terminal (T1, T2) and the other side of the device connection terminal. A bidirectional power supply device capable of bidirectional conversion operation of DC voltage and AC voltage between (T3 and T4).
The first relay circuit (REL1) and the second relay circuit (REL2) having the first contact, the second contact, and the output terminal, respectively, are connected directly or via other circuit elements.
Connect the center tap on the other side of the high frequency transformer (TRN) to the second contact of the second relay circuit, either directly or via another circuit element.
The upper terminal on the other side of the high frequency transformer (TRN) is connected to the first contact of the first relay circuit via at least the first rectifier element, and at the same time.
A bidirectional power supply device characterized in that the lower terminal on the other side of a high frequency transformer (TRN) is connected to the first contact of a first relay circuit via at least a second rectifying element. A switching element in which energizing elements that can pass an energizing current in the opposite direction to the ON current are connected in parallel, a high-voltage transformer (TRN) that has center taps on one side and the other side, and a computer circuit (MICOM) that receives operation instructions. , A first and second operation control circuits (CTL1, CTL2) that are controlled by a computer circuit and function in two modes, one side of the device connection terminal (T1, T2) and the other side of the device connection terminal. A bidirectional power supply device capable of bidirectional conversion operation of DC voltage and AC voltage between (T3 and T4).
The first relay circuit (REL1) and the second relay circuit (REL2) having the first contact, the second contact, and the output terminal, respectively, are connected directly or via other circuit elements.
The center tap on the other side of the high frequency transformer is connected to the first contact of the first relay circuit directly or via another circuit element, and of the second relay circuit directly or via another circuit element. A bidirectional power supply device characterized by connecting a second contact. The bidirectional power supply device according to claim 1 or 2, wherein the other circuit element is a choke coil. Claim 1 in which a capacitor (C2) for connecting the connection line to the ground is arranged in a connection line between the output terminal of the first relay circuit (REL1) and the first contact of the second relay circuit (REL2). The bidirectional power supply device according to any one of claims 3.

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