WO2016038967A1

WO2016038967A1 - Power conversion device

Info

Publication number: WO2016038967A1
Application number: PCT/JP2015/067955
Authority: WO
Inventors: 鵜野良之
Original assignee: 株式会社村田製作所
Priority date: 2014-09-11
Filing date: 2015-06-23
Publication date: 2016-03-17
Also published as: DE112015004158T5; CN106605357A; CN106605357B; JPWO2016038967A1; JP6202212B2

Abstract

A power conversion device (1) is provided with a primary side conversion circuit (10) and a secondary side conversion circuit (20), which are magnetically coupled to each other by means of a transformer (30), and transmits power in the insulating direction and non-insulating direction. Switch elements (Q11, Q13) and switch elements (Q12, Q14) of a full bridge circuit of the primary side conversion circuit (10) are alternately turned on and off. Switch elements (Q21, Q23) and switch elements (Q22, Q24) of a full bridge circuit of the secondary side conversion circuit (20) are alternately turned on and off. Consequently, the power conversion device which is capable of suppressing a loss in power transmission, and efficiently performing the power transmission is provided.

Description

Power converter

The present invention relates to a power conversion apparatus that performs power conversion between arbitrary input / output ports among a plurality of input / output ports.

Patent Document 1 discloses a power conversion circuit that performs power conversion between any two of the four input / output ports. The power conversion circuit includes a primary side conversion circuit having two input / output ports, and a secondary side conversion circuit magnetically coupled to the primary side conversion circuit and having two other input / output ports. The primary side conversion circuit and the secondary side conversion circuit are magnetically coupled by a center tap type transformer.

The primary side conversion circuit has a primary side full bridge circuit. The primary side full bridge circuit has a coupled inductor configured by magnetically coupling two inductors connected to both ends of the primary side coil of the transformer. The secondary conversion circuit has a secondary full bridge circuit. The secondary full bridge circuit has a coupled inductor configured by magnetically coupling two inductors connected to both ends of the secondary coil of the transformer. And the power conversion ratio of a primary side converter circuit and a secondary side converter circuit is changed by changing the ON time of a switching period. The amount of power transmission between the primary side conversion circuit and the secondary side conversion circuit is controlled by the phase difference of the switching period.

JP 2011-193713 A

In the power conversion circuit described in Patent Document 1, when the power transmission from the primary side to the secondary side is unnecessary, the phase difference between the switching periods of the primary side and secondary side full bridge circuits needs to be zero. . In this case, the electric power transmitted from the primary side to the secondary side is regenerated from the secondary side to the primary side. And since unnecessary loss occurs at the time of regeneration, there is a problem that efficient power transmission cannot be performed.

Therefore, an object of the present invention is to provide a power conversion device that can suppress loss during power transmission and perform power transmission efficiently.

The power conversion device of the present invention includes a first input / output port, a second input / output port, a first arm and a second arm in which an upper switch element and a lower switch element are connected in series, and the first arm And a first full bridge circuit in which the second arm is connected to the first input / output port, a third arm and a fourth arm in which an upper switch element and a lower switch element are connected in series, A secondary full bridge circuit in which the third arm and the fourth arm are connected to the second input / output port; a transformer having a primary coil and a secondary coil; and a first end of the primary coil A first inductor connected to one end, a second end connected to a connection point of the upper switch element and the lower switch element of the first arm, and a first end a second end of the primary coil. And the second end is A second inductor connected to a connection point of the upper switch element and the lower switch element of two arms, a first end connected to a first end of the secondary coil, and a second end connected to the third arm A third inductor connected to a connection point of the upper switch element and the lower switch element, a first end connected to a second end of the secondary coil, and a second end connected to the second arm of the fourth arm. A fourth inductor connected to a connection point of the upper switch element and the lower switch element; a third input / output port connected to a center tap of the primary coil; and a center tap of the secondary coil A fourth input / output port; a first switching control unit that alternately turns on and off the upper switch element of the first arm and the second arm; and the lower switch element; the third arm; A second switching control unit that alternately turns on and off the upper switch element of the four arms and the lower switch element, and the timing of turn-on and turn-off of the upper switch element of the first arm and the second arm is An operation mode in which the lower switch elements of the first arm and the second arm are simultaneously turned on and turned off, and the upper switch elements of the third arm and the fourth arm are turned on. And an operation mode in which the turn-off timing is the same and the turn-on and turn-off timings of the lower switch elements of the third arm and the fourth arm are the same. .

In this configuration, since the turn-on and turn-off timings of the upper switch element and the lower switch element of each arm are the same, the potential difference between both ends of the primary coil or the secondary coil of the transformer is zero. Therefore, no excitation current is generated in the transformer, and power transmission in the insulation direction (from the primary side to the secondary side or vice versa) is not performed. As a result, when power transmission in the non-insulated direction (between the first input / output port and the third input / output port) is performed, unnecessary loss caused by power regeneration as in the prior art can be suppressed, and efficiency can be improved. Good power transmission.

A fifth inductor connected between the center tap of the primary coil and the third input / output port; and a sixth inductor connected between the center tap of the secondary coil and the fourth input / output port. It is preferable to include at least one of the inductors.

In this configuration, by providing the fifth inductor or the sixth inductor and adjusting the inductance, the power transmission amount of the primary side conversion circuit or the secondary side conversion circuit can be adjusted.

The power conversion device of the present invention includes a first input / output port, a second input / output port, a first arm and a second arm in which an upper switch element and a lower switch element are connected in series, and the first arm And a first full bridge circuit in which the second arm is connected to the first input / output port, a third arm and a fourth arm in which an upper switch element and a lower switch element are connected in series, A secondary full bridge circuit in which a third arm and the fourth arm are connected to the second input / output port; a transformer having a primary coil and a secondary coil; and a first end of the first arm A third inductor is connected to a connection point of the upper switch element and the lower switch element, a second end is connected to a first end of the secondary coil, and a first end is the upper side of the second arm. Switch element and above A second inductor connected to a connection point of the switch element, a second end connected to a second end of the secondary coil, a third input / output port connected to a center tap of the primary coil, and the 2 A fourth input / output port connected to the center tap of the secondary coil, a fifth inductor connected between the center tap of the primary coil and the third input / output port, the first arm and the second A first switching control unit that alternately turns on and off the upper switch element of the arm and the lower switch element, the upper switch element of the third arm and the fourth arm, and the lower switch element alternately A second switching control unit that turns on and off at the same time, and the turn-on and turn-off timings of the upper switch elements of the first arm and the second arm are simultaneously And an operation mode in which turn-on and turn-off timings of the lower switch elements of the first arm and the second arm are simultaneous, and turn-on and turn-off of the upper switch elements of the third arm and the fourth arm. And the operation mode in which the turn-on and turn-off timings of the lower switch elements of the third arm and the fourth arm are the same.

In this configuration, when power transmission is performed in a non-insulated direction (between the first input / output port and the third input / output port), unnecessary loss caused by power regeneration as in the past can be suppressed, and efficiency can be reduced. Power transmission is possible.

It is preferable that a sixth inductor connected between the center tap of the secondary coil and the fourth input / output port is provided.

In this configuration, it is possible to adjust the power transmission amount of the secondary conversion circuit by providing a sixth inductor and adjusting its inductance.

The power conversion device of the present invention includes a first input / output port, a second input / output port, a first arm and a second arm in which an upper switch element and a lower switch element are connected in series, and the first arm And a first full bridge circuit in which the second arm is connected to the first input / output port, a third arm and a fourth arm in which an upper switch element and a lower switch element are connected in series, A secondary full bridge circuit in which a third arm and the fourth arm are connected to the second input / output port; a transformer having a primary coil and a secondary coil; and a first end of the first arm A first inductor connected to a connection point of the upper switch element and the lower switch element, a second end connected to a first end of the primary coil, and a first end connected to the upper side of the second arm Switch element and above A second inductor having a second end connected to a connection point of the switch element and having a second end connected to a second end of the primary coil; a third input / output port connected to a center tap of the primary coil; A first switching control unit that alternately turns on and off the upper switch element of the first arm and the second arm and the lower switch element; the upper switch element of the third arm and the fourth arm; A second switching control unit that alternately turns on and off the side switch elements, the turn-on and turn-off timings of the upper switch elements of the first arm and the second arm being the same, and the first arm and The second arm has an operation mode in which the lower switch element of the second arm is turned on and turned off at the same time.

In this configuration, when power transmission is performed in a non-insulated direction, unnecessary loss caused by power regeneration as in the past can be suppressed, and efficient power transmission can be performed. In addition, the number of parts is reduced, and the power transmission device can be downsized.

It is preferable that at least one of the first inductor, the second inductor, the third inductor, and the fourth inductor is magnetically coupled.

The power conversion device of the present invention includes a first input / output port, a second input / output port, a first arm and a second arm in which an upper switch element and a lower switch element are connected in series, and the first arm And a first full bridge circuit in which the second arm is connected to the first input / output port, a third arm and a fourth arm in which an upper switch element and a lower switch element are connected in series, A secondary full bridge circuit in which a third arm and the fourth arm are connected to the second input / output port; a transformer having a primary coil and a secondary coil; and a first end of the first arm A third inductor connected to a connection point of the upper switch element and the lower switch element, a second inductor connected to a first end of the secondary coil, and a second inductor connected to a center tap of the primary coil. 3 input / output ports A fifth inductor connected between a center tap of the primary coil and the third input / output port, the upper switch element of the first arm and the second arm, and the lower switch element, A first switching control unit that alternately turns on and off, and a second switching control unit that alternately turns on and off the upper switch element and the lower switch element of the third arm and the fourth arm, and The turn-on and turn-off timings of the upper switch elements of the first arm and the second arm are simultaneous, and the turn-on and turn-off timings of the lower switch elements of the first arm and the second arm are simultaneous. It has an operation mode.

The upper switch element and the lower switch element of the first arm, the second arm, the third arm, and the fourth arm are MOS-FETs having body diodes, and the first switching control unit is configured to perform the operation A first prohibiting unit that prohibits turning on the upper switch element or the lower switch element of the first arm and the second arm in the mode, and the second switching control unit is configured to It is preferable to have a second prohibition unit that prohibits the upper switch element or the lower switch element of the third arm and the fourth arm from being turned on.

In this configuration, power loss can be further reduced by not performing switching control of the upper switch element or the lower switch element.

The power conversion device of the present invention includes the upper switch element of the first arm and the lower switch element of the second arm, the lower switch element of the first arm, and the upper switch element of the second arm. A third switching control unit that alternately turns on and off; the upper switch element of the third arm; the lower switch element of the fourth arm; and the lower switch element and the fourth arm of the third arm. A fourth switching control unit for alternately turning on and off the upper switch element, a switching control mode by the first switching control unit and the second switching control unit, the third switching control unit and the fourth switching control unit It is preferable to include a switching unit that alternately switches between the switching control modes according to.

In this configuration, the power transmission in the insulation direction can be efficiently performed by alternately switching the mode in which power is transmitted in the insulation direction (from the primary side to the secondary side or vice versa) and the mode in which the power is not transmitted.

According to the present invention, efficient power transmission can be performed while suppressing loss during power transmission.

1 is a circuit diagram of a power conversion device according to a first embodiment. Block diagram showing functions of control unit The figure for demonstrating the function as a buck-boost circuit among the functions of the converter circuit of a power converter device The figure for demonstrating the function as a DAB converter among the converter circuit functions of a power converter device The figure which shows the voltage waveform of each part of a primary side converter circuit and a secondary side converter circuit, and the current waveform which flows into an inductor The timing chart of each switch element of a primary side conversion circuit, and the figure which shows the voltage waveform of each part of a primary side conversion circuit The timing chart of each switch element of a secondary side conversion circuit, and the figure which shows the voltage waveform of each part of a secondary side conversion circuit Circuit diagram of modification of power converter Circuit diagram of modification of power converter Circuit diagram of modification of power converter Circuit diagram of modification of power converter Circuit diagram of modification of power converter Circuit diagram of modification of power converter The timing chart of each switch element of a primary side conversion circuit, and the figure which shows the voltage waveform of each part of a primary side conversion circuit The figure for demonstrating the operation mode of a power converter device

(Embodiment 1)
FIG. 1 is a circuit diagram of a power conversion device 1 according to this embodiment.

The power conversion device 1 includes a primary side conversion circuit 10 and a secondary side conversion circuit 20. The primary side conversion circuit 10 and the secondary side conversion circuit 20 are magnetically coupled by a transformer 30. The primary side conversion circuit 10 includes a first input / output port P1 having input / output terminals IO1 and IO2, and a third input / output port P3 having input / output terminals IO2 and IO3. The secondary side conversion circuit 20 includes a second input / output port P2 having input / output terminals IO4 and IO5, and a fourth input / output port P4 having input / output terminals IO5 and IO6. The power conversion device 1 performs power conversion between any of the four input / output ports P1 to P4 and another input / output port.

The primary side conversion circuit 10 includes a primary side full bridge circuit (hereinafter simply referred to as a full bridge circuit). This full bridge circuit has switch elements Q11, Q12, Q13, and Q14. The switch elements Q11, Q12, Q13, Q14 are n-type MOS-FETs. A series circuit of the switch elements Q11 and Q12 is connected to the input / output terminals IO1 and IO2. The series circuit of the switch elements Q13 and Q14 is connected in parallel to the series circuit of the switch elements Q11 and Q12. A gate signal is input from the primary driver 13 to the gates of the switch elements Q11, Q12, Q13, and Q14. Thereby, each switch element Q11, Q12, Q13, Q14 is turned on and off.

The series circuit of the switch elements Q11 and Q12 is an example of the “first arm” in the present invention. The series circuit of the switch elements Q13 and Q14 is an example of the “second arm” in the present invention. The switch elements Q11 and Q13 are examples of the “upper switch element” in the present invention. The switch elements Q12 and Q14 are examples of the “lower switch element” in the present invention.

The first end of the inductor L11 is connected to the connection point of the switch elements Q11 and Q12. The first end of the inductor L12 is connected to the connection point of the switch elements Q13 and Q14 of the full bridge circuit. The second ends of the inductors L11 and L12 are connected to both ends of the primary coil of the transformer 30. The inductors L11 and L12 are coupled inductors that are magnetically coupled. The inductors L11 and L12 are examples of the “first inductor” and the “second inductor” in the present invention.

The transformer 30 includes

primary coils

31 and 32 and

secondary coils

33 and 34. The primary coils 31 and 32 are connected in series. The input / output terminal IO3 of the third input / output port P3 is connected to the connection point (center tap) of the

primary coils

31 and 32.

The secondary side conversion circuit 20 includes a secondary side full bridge circuit (hereinafter simply referred to as a full bridge circuit). This full bridge circuit has switch elements Q21, Q22, Q23, and Q24. The switch elements Q21, Q22, Q23, Q24 are n-type MOS-FETs. A series circuit of the switch elements Q21 and Q22 is connected to the input / output terminals IO4 and IO5. The series circuit of the switch elements Q23 and Q24 is connected in parallel to the series circuit of the switch elements Q21 and Q22. A gate signal is input from the secondary driver 23 to the gates of the switch elements Q21, Q22, Q23, and Q24. Thereby, each switch element Q21, Q22, Q23, Q24 is turned on / off.

The series circuit of the switch elements Q21 and Q22 is an example of the “third arm” in the present invention. The series circuit of the switch elements Q23 and Q24 is an example of the “fourth arm” in the present invention. The switch elements Q21 and Q22 are examples of the “upper switch element” in the present invention. The switch elements Q22 and Q24 are an example of the “lower switch element” in the present invention.

The first end of the inductor L21 is connected to the connection point of the switch elements Q21 and Q22. The first end of the inductor L22 is connected to the connection point of the switch elements Q23 and Q24 of the full bridge circuit. The second ends of the inductors L21 and L22 are connected to both ends of the secondary coil of the transformer 30. The inductors L21 and L22 are coupled inductors that are magnetically coupled. The inductors L21 and L22 are examples of the “third inductor” and the “fourth inductor” in the present invention.

The secondary coils 33 and 34 of the transformer 30 are connected in series. An input / output terminal IO6 of the fourth input / output port P4 is connected to a connection point (center tap) of the

secondary coils

33 and 34.

The power conversion apparatus 1 includes a control unit 35. The control unit 35 outputs a control signal to each of the primary side driver 13 and the secondary side driver 23. The primary side driver 13 and the secondary side driver 23 to which this control signal is input outputs a gate signal to each switch element.

FIG. 2 is a block diagram showing the function of the control unit 35. The control unit 35 includes a power conversion mode determination unit 351, a phase difference determination unit 352, a duty ratio determination unit 353, a primary side output unit 354, and a secondary side output unit 355.

The power conversion mode determination unit 351 determines the power conversion mode of the power conversion device 1 based on, for example, an external signal input to the control unit 35. The power conversion mode includes first to twelfth modes.

The first mode is a mode in which power input from the first input / output port P1 is converted and output to the third input / output port P3. The second mode is a mode in which power input from the first input / output port P1 is converted and output to the second input / output port P2. The third mode is a mode in which the power input from the first input / output port P1 is converted and output to the fourth input / output port P4.

The fourth mode is a mode in which power input from the third input / output port P3 is converted and output to the first input / output port P1. The fifth mode is a mode in which the power input from the third input / output port P3 is converted and output to the second input / output port P2. The sixth mode is a mode in which power input from the third input / output port P3 is converted and output to the fourth input / output port P4.

The seventh mode is a mode in which power input from the second input / output port P2 is converted and output to the first input / output port P1. The eighth mode is a mode in which power input from the second input / output port P2 is converted and output to the third input / output port P3. The ninth mode is a mode in which the power input from the second input / output port P2 is converted and output to the fourth input / output port P4.

The tenth mode is a mode in which power input from the fourth input / output port P4 is converted and output to the first input / output port P1. The eleventh mode is a mode in which power input from the fourth input / output port P4 is converted and output to the third input / output port P3. The twelfth mode is a mode in which power input from the fourth input / output port P4 is converted and output to the second input / output port P2.

The phase difference determination unit 352 determines the phase difference φ of the switching cycle of the switch elements included in the primary side conversion circuit 10 and the secondary side conversion circuit 20 according to the mode determined by the power conversion mode determination unit 351. Power is transmitted from the first input / output port P1 to the second input / output port P2 (or in the opposite direction) by the determined phase difference φ.

The duty ratio determination unit 353 determines the duty ratio of the switch element included in each of the primary side conversion circuit 10 and the secondary side conversion circuit 20 according to the determined mode. The voltage is controlled (stepped up or stepped down) in each of the primary side converter circuit 10 and the secondary side converter circuit 20 according to the determined duty ratio.

The primary side output unit 354 sends the gate signal to the gates of the switch elements Q11, Q12, Q13, and Q14 of the primary side conversion circuit 10 based on the mode determined by the power conversion mode determination unit 351. 13 to output. Thereby, each switch element Q11, Q12, Q13, Q14 is turned on and off. The primary side output unit 354 outputs a gate signal corresponding to the phase difference φ and the duty ratio determined by the phase difference determination unit 352 and the duty ratio determination unit 353. The primary side output unit 354 is an example of the “first switching control unit” in the present invention.

The secondary output unit 355 sends the gate signal to the gates of the switch elements Q21, Q22, Q23, and Q24 of the secondary conversion circuit 20 based on the mode determined by the power conversion mode determination unit 351. 23 to output. Thereby, each switch element Q21, Q22, Q23, Q24 is turned on / off. The secondary output unit 355 outputs a gate signal corresponding to the phase difference φ and the duty ratio determined by the phase difference determination unit 352 and the duty ratio determination unit 353. The secondary side output unit 355 is an example of the “second switching control unit” in the present invention.

The operation of the power conversion device 1 configured as described above will be described. The power converter 1 has a function as a step-up / step-down circuit and a function as a Dual Active Bridge (hereinafter DAB) converter circuit.

FIG. 3 is a diagram for explaining a function as a step-up / step-down circuit among the functions of the converter circuit of the power conversion device 1. FIG. 4 is a diagram for explaining a function as a DAB converter among the converter circuit functions of the power conversion device 1.

The function as a step-up / step-down circuit on the primary side conversion circuit 10 side of the power conversion device 1 will be described. As shown in FIG. 3A, for example, a series circuit of switch elements Q11, Q12 (or Q13, Q14) is connected to the input / output terminals IO1, IO2 of the first input / output port P1. Since the inductors L11 and L12 connected to the switch elements Q11 and Q12 (or Q13 and Q14) are magnetically coupled inductors, an equivalent circuit of the leakage inductors Lr1 and Lr2 and the exciting inductor M1 as shown in FIG. Can be represented.

In addition, since the current flowing through the exciting inductor M1 is distributed and flows to the

primary coils

31 and 32 of the transformer 30, the magnetic flux is canceled here, and the exciting inductor M1 and the input / output terminal IO3 are equivalent to being short-circuited. Can be considered. That is, a step-down circuit is connected between the first input / output port P1 and the third input / output port P3. Therefore, the voltage input from the first input / output port P1 is stepped down and output from the third input / output port P3. A booster circuit is connected between the third input / output port P3 and the first input / output port P1. Therefore, the voltage input from the third input / output port P3 is boosted and output from the first input / output port P1.

The step-up / step-down function on the secondary conversion circuit 20 side can be explained in the same manner as the primary conversion circuit 10 side. That is, the voltage input from the second input / output port P2 is stepped down and output from the fourth input / output port P4. The voltage input from the fourth input / output port P4 is boosted and output from the second input / output port P2.

Next, the function of the power conversion device 1 as a DAB converter circuit will be described. As shown in FIG. 4, each of the primary side conversion circuit 10 and the secondary side conversion circuit 20 includes a full bridge circuit. Since the inductors L11 and L12 (or L21 and L22) are coupled inductors that are magnetically coupled, they can be represented by an equivalent circuit of leakage inductors Lr1 and Lr2 (or Lr3 and Lr4) and excitation inductors. Since current flows through the inductors L11 and L12 (or L21 and L22) in the opposite direction to the polarity, the exciting inductor is canceled and only the leakage inductors Lr1 and Lr2 (or Lr3 and Lr4) act. The primary side conversion circuit 10 and the secondary side conversion circuit 20 are magnetically coupled.

That is, a DAB converter circuit that inputs and outputs the first input / output port P1 and the second input / output port P2 is configured. Therefore, the first arm and the second arm are switched with a phase difference of 180 degrees (π), and the third arm and the fourth arm are switched with a phase difference of 180 degrees (π). By adjusting the phase difference between the switching periods of the switch elements on the second side and the secondary side conversion circuit 20 side, the power inputted to the first input / output port P1 (or the third input / output port P3) is converted and the second 2 input / output port P2 (or fourth input / output port P4). Further, the power input to the second input / output port P2 (or the fourth input / output port P4) can be converted and transmitted to the first input / output port P1 (or the third input / output port P3).

Hereinafter, the operation of the power conversion apparatus 1 will be described.

FIG. 5 is a diagram illustrating voltage waveforms of the respective parts of the primary side conversion circuit 10 and the secondary side conversion circuit 20 and current waveforms flowing through the inductor L11. Here, Vu1 is the drain-source voltage of the switch element Q12, Vv1 is the drain-source voltage of the switch element Q14, Vu2 is the drain-source voltage of the switch element Q22, and Vv2 is the drain of the switch element Q24. The voltage between the sources (see FIG. 1).

In this example, an input power supply is connected to the first input / output port P1, a load is connected to the other ports, Vu1 and Vv1 are each on-time δ, a phase difference of 180 degrees from each other, and Vu2 and Vv2 are respectively The control unit 35 performs switching control of each switch element of the primary side conversion circuit 10 and the secondary side conversion circuit 20 so that the ON time δ is reached and the phase difference is 180 degrees.

As shown in the waveform of the current I1 in FIG. 5, when Vu1 is high (H) and Vv1 is low (L), the input / output terminal IO1, the switch element Q11, the inductor L11, the primary coil 31 of the transformer 30, and the input A current flows in the order of the output terminal IO3. When Vu1 is low (L) and Vv1 is high (H), current flows in the order of input / output terminal IO1, switch element Q13, inductor L12, primary coil 32 of transformer 30, and input / output terminal IO3. When Vu1 and Vv1 are low (L), current flows in the order of inductors L11 and L12 →

primary coils

31 and 32 of transformer 30 → input / output terminal IO3 → load → input / output terminal IO2 → switch elements Q12 and Q14. That is, by repeating the high and low of Vu1 and Vv1, the voltage input from the first input / output port P1 is stepped down and output to the third input / output port P3. The voltage step-down ratio at this time can be determined by the ON time δ.

For power conversion from the third input / output port P3 to the first input / output port P1, the voltage input from the third input / output port P3 is boosted by repeating high and low of Vu1 and Vv1. Are output to the first input / output port P1. The step-up ratio can be determined by the on time δ. Further, the secondary side conversion circuit 20 side can be explained in the same manner as the primary side conversion circuit 10 side.

In addition, when a current flows in the primary side conversion circuit 10 as described above, a voltage is applied to the

primary coils

31 and 32 of the transformer 30 and a voltage is induced in the

secondary coils

33 and 34 of the transformer 30. . When the switching elements of the secondary conversion circuit 20 are controlled to be switched so that Vu2 and Vv2 have a phase difference φ (> 0) from Vu1 and Vv1, the second input / output port P2 (or the fourth input / output port) Current flows to P4). Thereby, power transmission from the primary side conversion circuit 10 to the secondary side conversion circuit 20 is performed.

For example, when the secondary coil 33 side of the transformer 30 is at a high potential, when the switch elements Q21 and Q24 are on, the secondary side conversion circuit 20 causes the secondary coil 33 of the transformer 30 → the inductor L21 → the switch element Q21. → A current flows through the path of the input / output terminal IO4. Further, when the secondary coil 34 side of the transformer 30 is at a high potential, when the switch elements Q22 and Q23 are turned on, the path of the secondary coil 34 of the transformer 30 → the inductor L22 → the switch element Q23 → the input / output terminal IO4. Current flows.

In this way, by switching the switching elements of the primary side conversion circuit 10 and the secondary side conversion circuit 20 with the phase difference φ (> 0), the voltage input from the first input / output port P1 becomes DAB. It is transmitted to the secondary conversion circuit 20 side by the function as a converter circuit, and is output from the second input / output port P2 and the fourth input / output port P4. As shown in FIG. 5, when the phase difference φ is changed, the time T1 when Vu1 and Vu2 are high (switch elements Q11 and Q21 are on) and Vv1 and Vv2 are low (switch elements Q14 and Q24 are on) changes. Similarly, the time T2 when Vu1 and Vu2 are low (switch elements Q12 and Q22 are on) and Vv1 and Vv2 are high (switch elements Q13 and Q23 are on) changes. Thus, the amount of power transmitted from the primary side conversion circuit 10 to the secondary side conversion circuit 20 can be controlled by the phase difference φ. The same applies to power transmission from the third input / output port P3 to the second input / output port P2 or the fourth input / output port P4.

Further, by changing the phase difference φ, power is transferred from the second input / output port P2 to the first input / output port P1 (or the third input / output port P3), and the fourth input / output port P4 to the first input / output port. Power transmission to P1 (or third input / output port P3) becomes possible. Specifically, the switching elements of the primary side conversion circuit 10 and the secondary side conversion circuit 20 are controlled to be switched with a phase difference φ (<0), whereby power is transferred from the secondary side conversion circuit 20 to the primary side conversion circuit 10. Is transmitted.

By setting the phase difference φ to 0 and controlling the switching elements of the primary side conversion circuit 10 and the secondary side conversion circuit 20, power transmission in the insulation direction is not performed. The primary side conversion circuit 10 and the secondary side conversion circuit 20 are symmetrical circuits. Therefore, when a power source such as a battery is connected to each of the first input / output port P1 and the second input / output port P2 and the phase difference φ is 0, the primary side conversion circuit 10 and the secondary side conversion circuit 20 are symmetrical. Operate. In this case, the power transmitted from the primary side conversion circuit 10 to the secondary side conversion circuit 20 is regenerated from the secondary side conversion circuit 20 to the primary side conversion circuit 10. Similarly, the power transmitted from the secondary side conversion circuit 20 to the primary side conversion circuit 10 is regenerated from the primary side conversion circuit 10 to the secondary side conversion circuit 20. As a result, power transmission in the insulation direction is not performed. The same applies to the third input / output port P3 and the fourth input / output port P4. However, in this case, wasteful power consumption occurs due to regeneration.

Thus, the power conversion device 1 according to the present embodiment, when performing only power transmission in the non-insulating direction, prevents the primary side conversion circuit 10 and the secondary side conversion circuit 20 from generating unnecessary power consumption due to regeneration. The switching element is controlled to be switched. Hereinafter, switching control in the case where only power transmission in the non-insulating direction is performed will be described.

FIG. 6 is a timing chart of the switching elements Q11, Q12, Q13, and Q14 of the primary side conversion circuit 10 and a diagram showing voltage waveforms of each part of the primary side conversion circuit 10. In this example as well, as in FIG. 5, it is assumed that an input power source is connected to the first input / output port P1.

On the primary side conversion circuit 10 side, the control unit 35 alternately turns on and off the switch elements Q11 and Q13 and the switch elements Q12 and Q14. When the switch elements Q11 and Q13 are on and the switch elements Q12 and Q14 are off, the path of the input / output terminal IO1, the switch element Q11, the inductor L11, the primary coil 31 of the transformer 30, the input / output terminal IO3, and the input / output terminal Current flows through the path of IO1 → switch element Q13 → inductor L12 → primary coil 32 of transformer 30 → input / output terminal IO3. At this time, the potentials of Vu1 and Vv1 are high (H). When the switch elements Q11, Q13 are off and the switch elements Q12, Q14 are on, the input / output terminal IO2 → switch elements Q12, Q14 → inductors L11, L12 →

primary coils

31, 32 of the transformer 30 → input / output terminals. A current flows through the path of IO3. At this time, the potentials of Vu1 and Vv1 are low (L).

That is, the potential difference Vuv1 between the connection point of the switch elements Q11 and Q12 and the connection point of the switch elements Q13 and Q14 is always 0. For this reason, the voltage applied to the

primary coils

31 and 32 of the transformer 30 is 0, and power transmission from the first input / output port P1 to the secondary side conversion circuit 20 side is not performed. The same applies to power transmission from the third input / output port P3 to the secondary side conversion circuit 20 side.

FIG. 7 is a timing chart of each switch element Q21, Q22, Q23, Q24 of the secondary side conversion circuit 20, and a diagram showing voltage waveforms of each part of the secondary side conversion circuit 20. In this example, it is assumed that an input power source is connected to the second input / output port P2.

On the secondary conversion circuit 20 side, the control unit 35 turns on and off the switch elements Q21 and Q23 and the switch elements Q22 and Q24 alternately. When the switch elements Q21 and Q23 are on and the switch elements Q22 and Q24 are off, the input / output terminal IO4 → switch element Q21 → inductor L21 → secondary coil 33 of the transformer 30 → input / output terminal IO6 path and input / output terminal Current flows in the path of IO4 → switch element Q23 → inductor L22 → secondary coil 34 of transformer 30 → input / output terminal IO6. At this time, the potentials of Vu1 and Vv1 are high (H). When the switch elements Q21, Q23 are off and the switch elements Q22, Q24 are on, the input / output terminal IO5 → switch elements Q22, Q24 → inductors L21, L22 →

secondary coils

33, 34 of the transformer 30 → input / output terminals. A current flows through the path of IO6. At this time, the potentials of Vu2 and Vv2 are low (L).

That is, the potential difference Vuv2 between the connection point of the switch elements Q21 and Q22 and the connection point of the switch elements Q23 and Q24 is always 0. For this reason, the voltage applied to the

secondary coils

33 and 34 of the transformer 30 is 0, and power transmission from the second input / output port P2 to the primary side conversion circuit 10 is not performed. The same applies to power transmission from the fourth input / output port P4 to the primary side conversion circuit 10 side.

As described above, in the present embodiment, voltage is not applied to the

primary coils

31 and 32 and the

secondary coils

33 and 34 of the transformer 30 so that power transmission in the insulation direction is not performed. No wasteful power consumption due to regeneration occurs. Further, there is no need to synchronize the switching control between the primary side conversion circuit 10 and the secondary side conversion circuit 20, and power transmission within the primary side conversion circuit 10 (for example, from the first input / output port P1 to the third input) Power transmission to the output port P3) and power transmission in the secondary conversion circuit 20 (for example, power transmission from the second input / output port P2 to the fourth input / output port P4) can be performed independently of each other. . Further, when power transmission is performed between the first input / output port P1 and the third input / output port P3 and it is not necessary to perform power transmission between the second input / output port P2 and the fourth input / output port P4. Only the primary side conversion circuit 10 may be switched and the switching of the secondary side conversion circuit 20 may be stopped. Similarly, only the secondary side conversion circuit 20 may be controlled to stop the switching of the primary side conversion circuit 10.

As described above, the power conversion device 1 has a function as a step-up / step-down circuit and a function as a DAB converter circuit, and between any of the four input / output ports P1 to P4 and another input / output port. Power conversion can be performed. When power transmission is performed only in the non-insulated direction, unnecessary power consumption does not occur and efficient power transmission can be performed by preventing power transmission in the insulating direction.

8, 9, 10, 11, 12, and 13 are circuit diagrams of modified examples of the power converter.

The inductors L11 and L12 (or L21 and L22) included in the power conversion device 1A shown in FIG. 8 are not magnetically coupled and are independent of each other. Even in this case, as in the power converter 1, efficient power transmission can be performed.

The power converter 1B shown in FIG. 9 includes an inductor L13 connected between the center taps of the

primary coils

31 and 32 and the input / output terminal IO3, the center taps of the

secondary coils

33 and 34, and the input / output terminal IO6. And an inductor L23 connected between the two. In this case, the inductors L11 and L12 (or L21 and L22) may be magnetically coupled or may be independent of each other.

Here, the inductor L13 is an example of a “fifth inductor” according to the present invention, and the inductor L23 is an example of a “sixth inductor” according to the present invention.

The power converter 1C shown in FIG. 10 has a configuration that does not include the inductors L11, L12, and L23 in the circuit configuration of the power converter 1B. The power conversion device 1D shown in FIG. 11 has a configuration that does not include the inductors L11 and L12 in the circuit configuration of the power conversion device 1B. In this case, the inductors L21 and L22 may be magnetically coupled or may be independent of each other.

The power conversion device 1E shown in FIG. 12 includes three input / output ports P1, P2, and P3. The power conversion device 1E is a power conversion circuit that performs power conversion between any two of the input / output ports P1, P2, and P3. And secondary side circuit 20 of power converter 1E is not provided with inductors L21 and L22.

The power conversion device 1F shown in FIG. 13 includes three input / output ports P1, P2, and P3, similarly to the power conversion device 1E. And the primary side circuit 10 of the power converter device 1F is not provided with the inductors L11 and L12, but is provided with the inductor L13. The secondary circuit 20 includes only the inductor L21.

Even with the circuit configurations of the power transmission devices shown in FIGS. 9 to 13, efficient power transmission can be performed in the same manner as the power conversion device 1.

(Embodiment 2)
In the second embodiment, when power transmission in the insulation direction is not performed, only the switch elements Q11 and Q13 are turned on and off in the primary side conversion circuit 10, and only the switch elements Q21 and Q23 are turned on and off in the secondary side conversion circuit 20. . The primary side output unit 354 shown in FIG. 2 is an example of the “first prohibition unit” according to the present invention. The secondary output unit 355 is an example of the “second prohibition unit” according to the present invention.

FIG. 14 is a timing chart of each switch element Q11, Q12, Q13, Q14 of the primary side conversion circuit 10 and a diagram showing voltage waveforms of each part of the primary side conversion circuit 10. The power conversion device of this embodiment is the same as that in FIG. 1 and will be described assuming that an input power supply is connected to the first input / output port P1. Since the switching control of the primary side conversion circuit 10 and the secondary side conversion circuit 20 is the same, only the switching control of the primary side conversion circuit 10 will be described.

On the primary side conversion circuit 10 side, the control unit 35 turns on and off only the switch elements Q11 and Q13 at the same time, and always turns off the switch elements Q12 and Q14. In this case, considering the equivalent circuit of FIG. 3A, the switch elements Q21 and Q23 are MOS-FETs having body diodes, so that only the switch elements Q11 and Q13 can be switched even if they are always off. The rectification is performed by the body diode.

When the switch elements Q11 and Q13 are on, the currents I1 and I2 flowing through the inductors L11 and L12 rise. When switch elements Q11 and Q13 are turned off, the energy stored in inductors L11 and L12 is released through the body diodes of switch elements Q12 and Q14. I1 and I2 from which the energy stored in the inductors L11 and L12 is released become zero. At this time, since the body diode is turned off, the voltage Vd appears.

If a power source such as a battery is connected to the third input / output port P3 and the switching elements Q12, Q14 are controlled to switch, and the switching elements Q12, Q14 are on, the third input / output port P3 → the inductors L11, L12. → Current flows through the path of the switch elements Q12 and Q14. That is, a regenerative current (broken line portion in FIG. 7) is generated from the third input / output port to the first input / output port P1. On the other hand, in this embodiment, since the switch elements Q12 and Q14 are always turned off, generation of regenerative current can be suppressed and loss due to regenerative current can be suppressed.

For example, when power is supplied from the input power source connected to the first input / output port P1 to the load connected to the third input / output port P3, if the load is a light load, the current to the light load Is small. For this reason, even when the switching elements Q12 and Q14 are not switched and rectified using a body diode, the loss in the body diode is not large.

As described above, when the power transmission in the insulation direction is not performed and only the power transmission in the non-insulation direction is performed, the primary side conversion circuit 10 performs switching control only on the switch elements Q11 and Q13, and the secondary side. In the conversion circuit 20, only the switching elements Q21 and Q23 are switched. Thereby, generation | occurrence | production of regenerative current can be suppressed and the loss by regenerative current can be suppressed. As a result, the efficiency of power transmission in the non-insulating direction can be improved.

(Embodiment 3)
In the power converter according to the present embodiment, when power is transmitted in the insulation direction, the power is transmitted in the insulation direction (hereinafter referred to as the insulation power transmission mode), and the power is not transmitted in the insulation direction. A mode for transmitting power only to the power source (hereinafter referred to as a non-insulated power transmission mode) is alternately switched.

FIG. 15 is a diagram for explaining an operation mode of the power conversion device 1.

Hereinafter, in FIG. 1, the input power source is connected to the first input / output port P1, the load is connected to the second input / output port P2, and power is transmitted from the first input / output port P1 to the second input / output port P2. explain.

When power is transmitted from the first input / output port P1 to the second input / output port P2, the control unit 35, as described in the first embodiment, switches each switch element of the primary side conversion circuit 10 and the secondary side conversion circuit 20. Is controlled by the phase difference φ. The phase difference φ at this time is a value that allows the power conversion device 1 to operate with high efficiency. In the case of a light load, the power conversion mode determination unit 351 switches to an operation mode in which the insulated power transmission mode and the non-insulated power transmission mode are alternately executed as shown in FIG. The primary side output unit 354 and the secondary side output unit 355 perform switching control of each switch element based on the operation mode determined by the power conversion mode determination unit 351.

In the insulated power transmission mode, the primary side output unit 354 and the secondary side output unit 355 of the control unit 35 perform switching control of each switch element of the primary side conversion circuit 10 and the secondary side conversion circuit 20 with the phase difference φ. . In the non-insulated power transmission mode, the primary side output unit 354 and the secondary side output unit 355 of the control unit 35 alternately turn on and off the switch elements Q11 and Q13 of the primary side conversion circuit 10 and the switch elements Q12 and Q14. Then, the switching elements Q21 and Q23 of the secondary side conversion circuit 20 and the switching elements Q22 and Q24 are alternately turned on and off. The power conversion mode determination unit 351 is an example of the “switching unit” according to the present invention. The primary side output unit 354 is an example of the “third switching control unit” according to the present invention. The secondary side output unit 355 is an example of the “fourth switching control unit” according to the present invention.

When the power transmitted in the insulation direction is small, that is, when the phase difference φ is small, a regenerative current is generated and the loss increases. However, as in this embodiment, the operation is performed with a phase difference φ that can be operated with high efficiency, and the power transmitted in the insulation direction is adjusted by switching between the insulated power transmission mode and the non-insulated power transmission mode, thereby moving in the insulation direction. The efficiency of power transmission can be improved.

IO1, IO2, IO3, IO4, IO5, IO6 ... I / O terminals L11, L12 ... Inductors L21, L22 ... Inductors L13, L23 ... Inductor P1 ... First I / O port P2 ... Second I / O port P3 ... Third I / O Port P4 ... Fourth input / output port Q11, Q12, Q13, Q14 ... Switch elements Q21, Q22, Q23, Q24 ... Switch elements R11, R12, R13, R14 ... Voltage divider resistors R21, R22, R23, R24 ...

Voltage divider resistors

1, 1A, 1B, 1C, 1D, 1E, 1F ... power converter 10 ... primary side converter circuit 13 ... primary side driver 20 ... secondary side converter circuit 23 ... secondary side driver 30 ...

transformers

31, 32 ...

primary coil

33, 34 ... secondary coil 35 ... control unit 351 ... power conversion mode determining unit 352 ... phase difference determining unit 353 ... duty ratio determining unit 3 4 ... the primary-side output section 355 ... the secondary side output section

Claims

A first input / output port and a second input / output port;
A primary full bridge having a first arm and a second arm in which an upper switch element and a lower switch element are connected in series, wherein the first arm and the second arm are connected to the first input / output port. Circuit,
A secondary full bridge having a third arm and a fourth arm in which an upper switch element and a lower switch element are connected in series, wherein the third arm and the fourth arm are connected to the second input / output port Circuit,
A transformer having a primary coil and a secondary coil;
A first inductor having a first end connected to a connection point of the upper switch element and the lower switch element of the first arm, and a second end connected to a first end of the primary coil;
A second inductor having a first end connected to a connection point of the upper switch element and the lower switch element of the second arm, and a second end connected to a second end of the primary coil;
A third inductor having a first end connected to a connection point of the upper switch element and the lower switch element of the third arm, and a second end connected to the first end of the secondary coil;
A fourth inductor having a first end connected to a connection point of the upper switch element and the lower switch element of the fourth arm, and a second end connected to a second end of the secondary coil;
A third input / output port connected to the center tap of the primary coil;
A fourth input / output port connected to the center tap of the secondary coil;
A first switching control unit for alternately turning on and off the upper switch element and the lower switch element of the first arm and the second arm;
A second switching control unit that alternately turns on and off the upper switch element and the lower switch element of the third arm and the fourth arm;
With
The turn-on and turn-off timings of the upper switch elements of the first arm and the second arm are simultaneous, and the turn-on and turn-off timings of the lower switch elements of the first arm and the second arm are simultaneous. A certain mode of operation,
The turn-on and turn-off timings of the upper switch elements of the third arm and the fourth arm are simultaneous, and the turn-on and turn-off timings of the lower switch elements of the third arm and the fourth arm are simultaneous. A power conversion device having at least one of an operation mode.
A fifth inductor connected between the center tap of the primary coil and the third input / output port; and a sixth inductor connected between the center tap of the secondary coil and the fourth input / output port. Comprising at least one of the inductors,
The power conversion device according to claim 1.
A first input / output port and a second input / output port;
A primary full bridge having a first arm and a second arm in which an upper switch element and a lower switch element are connected in series, wherein the first arm and the second arm are connected to the first input / output port. Circuit,
A secondary full bridge having a third arm and a fourth arm in which an upper switch element and a lower switch element are connected in series, wherein the third arm and the fourth arm are connected to the second input / output port Circuit,
A transformer having a primary coil and a secondary coil;
A third inductor having a first end connected to a connection point of the upper switch element and the lower switch element of the first arm and a second end connected to a first end of the secondary coil;
A fourth inductor having a first end connected to a connection point of the upper switch element and the lower switch element of the second arm, and a second end connected to a second end of the secondary coil;
A third input / output port connected to the center tap of the primary coil;
A fourth input / output port connected to the center tap of the secondary coil;
A fifth inductor connected between the center tap of the primary coil and the third input / output port;
A first switching control unit for alternately turning on and off the upper switch element and the lower switch element of the first arm and the second arm;
A second switching control unit that alternately turns on and off the upper switch element and the lower switch element of the third arm and the fourth arm;
With
The turn-on and turn-off timings of the upper switch elements of the first arm and the second arm are simultaneous, and the turn-on and turn-off timings of the lower switch elements of the first arm and the second arm are simultaneous. A certain mode of operation,
The turn-on and turn-off timings of the upper switch elements of the third arm and the fourth arm are simultaneous, and the turn-on and turn-off timings of the lower switch elements of the third arm and the fourth arm are simultaneous. A power conversion device having at least one of an operation mode.
The power converter according to claim 3, comprising a sixth inductor connected between a center tap of the secondary coil and the fourth input / output port.
A first input / output port and a second input / output port;
A primary full bridge having a first arm and a second arm in which an upper switch element and a lower switch element are connected in series, wherein the first arm and the second arm are connected to the first input / output port. Circuit,
A secondary full bridge having a third arm and a fourth arm in which an upper switch element and a lower switch element are connected in series, wherein the third arm and the fourth arm are connected to the second input / output port Circuit,
A transformer having a primary coil and a secondary coil;
A first inductor having a first end connected to a connection point of the upper switch element and the lower switch element of the first arm, and a second end connected to a first end of the primary coil;
A second inductor having a first end connected to a connection point of the upper switch element and the lower switch element of the second arm, and a second end connected to a second end of the primary coil;
A third input / output port connected to the center tap of the primary coil;
A first switching control unit for alternately turning on and off the upper switch element and the lower switch element of the first arm and the second arm;
A second switching control unit that alternately turns on and off the upper switch element and the lower switch element of the third arm and the fourth arm;
With
The turn-on and turn-off timings of the upper switch elements of the first arm and the second arm are simultaneous, and the turn-on and turn-off timings of the lower switch elements of the first arm and the second arm are simultaneous. A power conversion device having an operation mode.
6. The power conversion device according to claim 1, wherein at least one of the first inductor, the second inductor, and the third inductor and the fourth inductor is magnetically coupled.
A first input / output port and a second input / output port;
A primary full bridge having a first arm and a second arm in which an upper switch element and a lower switch element are connected in series, wherein the first arm and the second arm are connected to the first input / output port. Circuit,
A secondary full bridge having a third arm and a fourth arm in which an upper switch element and a lower switch element are connected in series, wherein the third arm and the fourth arm are connected to the second input / output port Circuit,
A transformer having a primary coil and a secondary coil;
A third inductor having a first end connected to a connection point of the upper switch element and the lower switch element of the first arm and a second end connected to a first end of the secondary coil;
A third input / output port connected to the center tap of the primary coil;
A fifth inductor connected between the center tap of the primary coil and the third input / output port;
A first switching control unit for alternately turning on and off the upper switch element and the lower switch element of the first arm and the second arm;
A second switching control unit that alternately turns on and off the upper switch element and the lower switch element of the third arm and the fourth arm;
With
The turn-on and turn-off timings of the upper switch elements of the first arm and the second arm are simultaneous, and the turn-on and turn-off timings of the lower switch elements of the first arm and the second arm are simultaneous. A power conversion device having an operation mode.
The upper switch element and the lower switch element of the first arm, the second arm, the third arm, and the fourth arm are MOS-FETs having body diodes,
The first switching control unit includes a first prohibiting unit that prohibits turning on the upper switch element or the lower switch element of the first arm and the second arm in the operation mode,
The second switching control unit includes a second prohibiting unit that prohibits the upper switch element or the lower switch element of the third arm and the fourth arm from being turned on in the operation mode.
The power converter device in any one of Claim 1 to 7.
A third switch that alternately turns on and off the upper switch element of the first arm, the lower switch element of the second arm, and the lower switch element of the first arm and the upper switch element of the second arm; A switching control unit;
A fourth switch that alternately turns on and off the upper switch element of the third arm and the lower switch element of the fourth arm, and the lower switch element of the third arm and the upper switch element of the fourth arm. A switching control unit;
A switching unit that alternately switches between a switching control mode by the first switching control unit and the second switching control unit, and a switching control mode by the third switching control unit and the fourth switching control unit;
The power converter device according to claim 1, comprising: