JP2017118047A - Magnetic element integrating transformer reactor and power conversion circuit system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a magnetic element integrating a transformer reactor in which the substrate area and core volume are reduced while improving the conversion efficiency, and to provide a power conversion circuit system.SOLUTION: At the opposite ends of an E type core 10 having legs in the center and at the opposite ends, primary transformer coils 12a, 12b are placed, and secondary transformer coils 14a, 14b are placed. A reactor coil 16a is placed in the center of the core 10, and connected with the middle point of the primary transformer coils 12a, 12b. The reactor coil is reduced by supplying the in-phase current to the primary transformer coils 12a, 12b thereby operating the magnetic element as a reactor, and supplying the negative-phase current to the primary transformer coils 12a, 12b thereby operating the magnetic element as a transformer. The negative-phase current does not flow through the reactor coil 16a, and thereby there is no AC resistance loss.SELECTED DRAWING: Figure 8

Description

  The present invention relates to a transformer-integrated magnetic element and a power conversion circuit system, and more particularly to a power conversion circuit system including a plurality of input / output ports.

  With the development and popularization of electric-rich vehicles such as hybrid vehicles, electric vehicles, and fuel cell vehicles, on-board power supply circuits are becoming more complex and larger. For example, in a hybrid vehicle, a traveling battery, a system battery, an external power supply circuit for plug-in, a DC / DC converter for supplying direct current power of the traveling battery to the traveling motor, and direct current power of the traveling battery to alternating current DC / AC converter for converting to electric power, DC / DC converter for supplying DC power of the traveling battery to the electric power steering (EPS), DC / DC for supplying DC power of the traveling battery to the auxiliary machine There are DC converters, etc., and the configuration is complicated.

  Therefore, development of a multi-port power supply having a plurality of inputs / outputs in one circuit is underway. It has been proposed to reduce the size of a power supply circuit by sharing wirings, semiconductor elements, and the like with a multiport power supply. At this time, it is effective to wind the transformer coil and the reactor coil around the core so as not to interfere with each other.

  Patent Document 1 describes a configuration in which a transformer coil and a reactor coil are wound around a core having three legs so as not to interfere with each other, and the dead space between magnetic elements and the heat sink size are reduced. it can.

  FIG. 11 shows a cross-sectional view of the magnetic element described in this document. Transformer coils 12a, 12b, 14a, 14b are arranged on both leg portions of the core 10 having three legs, and two reactor coils 16a, 16b are arranged on the center leg portion. The transformer coils 12a and 12b are primary (low voltage side) transformer coils, and the transformer coils 14a and 14b are secondary (high voltage side) transformer coils.

  12A and 12B show a magnetic flux change and a circuit configuration when the magnetic element of FIG. 11 is operated as a transformer. When current is passed so that the transformer coils 12a and 12b are in opposite phases, the magnetic flux generation directions by the transformer coils 12a and 12b are reversed at both ends, so that the magnetic flux changes at the center leg are canceled out. Therefore, magnetic flux does not pass through the reactor coils 16a and 16b arranged at the center leg, and no electromotive force is generated.

  On the other hand, FIG. 13A and FIG. 13B show magnetic flux changes and circuit configurations when the magnetic element of FIG. 11 is operated as a reactor. When current flows so that the transformer coils 12a and 12b are in phase with each other, the magnetic flux generated from the reactor coils 16a and 16b arranged at the center leg is linked to the transformer coils 12a and 12b. However, since the upper and lower transformer coils 12a and 12b through the center tap are opposite to each other, the electromotive force of the entire coil becomes zero and the transformer does not operate. Based on the above principle, the transformer coil and the reactor coil operate without interfering with each other.

JP 2012-134266 A

  In the conventional technology, the dead space between the magnetic elements and the heat sink size can be reduced by arranging the transformer coil and the reactor coil in the core having three legs, but the number of components and the winding length are reduced. In addition, further increase in conversion efficiency is also required.

  FIG. 14 shows the flow of the common-mode current during the reactor operation when the magnetic element shown in FIG. 11 is viewed from above, and FIG. 15 shows the reverse of the transformer operation when the magnetic element shown in FIG. 11 is viewed from above. The flow of phase current is shown.

  At the time of the reactor operation, as shown in FIG. 14, the current flows clockwise through the reactor coil 16a at the center leg from the Mu terminal, and then flows counterclockwise through the transformer coil 12a at the left leg. To. On the other hand, the current flows clockwise through the reactor coil 16a at the center leg from the Mv terminal, then flows counterclockwise through the transformer coil 12b at the right leg, and reaches the C terminal. Magnetic flux generated from the reactor coil 16a arranged at the center leg is linked to the transformer coils 12a and 12b, but the generated electromotive force is reversed between the upper and lower transformer coils 12a and 12b via the center tap. The electromotive force of the entire coil is zero, and it does not operate as a transformer.

  On the other hand, at the time of the transformer operation, as shown in FIG. 15, the current flows clockwise through the reactor coil 16a at the center leg from the Mu terminal, and then flows counterclockwise through the transformer coil 12a at the left leg. Next, the right leg transformer coil 12b flows clockwise, and the center leg reactor coil 16a flows counterclockwise to the Mv terminal. Since the direction of magnetic flux generation by the transformer coils 12a and 12b is reversed at both ends, the magnetic flux change at the center leg is canceled out. Therefore, no magnetic flux passes through the reactor coil 16a arranged at the center leg, and no electromotive force is generated, so the reactor operation is not affected.

  However, since the common-mode current flows not only through the reactor coil 16a but also the reverse-phase current flows through the reactor coil 16a as shown in FIG. 15, the reverse-phase current causes an AC resistance loss in the reactor coil 16a, resulting in conversion efficiency. There is a problem that decreases.

  An object of the present invention is to provide a transformer-integrated magnetic element and a power conversion circuit system capable of reducing the substrate area and the core volume and further improving the power conversion efficiency.

  The transformer-reactor-integrated magnetic element of the present invention includes a core having a central leg portion and leg portions at both ends, a first primary transformer coil wound around one of the leg portions at both ends, and a first A secondary transformer coil, and a second primary transformer coil and a second secondary transformer coil wound around either one of the leg portions at both ends, the first primary transformer coil, The second primary transformer coil is connected in series and wound in the differential direction, and the first secondary transformer coil and the second secondary transformer coil are connected in series and wound in the differential direction. A reactor coil is wound around the center leg of the core, and its end is connected to the midpoint of the first primary transformer coil and the second primary transformer coil, 1 primary transformer coil and second primary transformer And reactor operation by common mode current is supplied to the Nsukoiru, reverse phase current to the first primary transformer coil and the second primary transformer coil is characterized in that the transformer operates by being supplied.

  The power conversion circuit system of the present invention is a primary side conversion circuit, and includes a left arm and a right arm between a primary side positive bus and a primary side negative bus, and the left arm and the right arm are each in series. A first primary transformer coil and a second primary transformer between a connection point of the two switching transistors of the left arm and a connection point of the two switching transistors of the right arm. A primary side conversion circuit and a secondary side conversion circuit in which coils are connected in series, and a left arm and a right arm are provided between a secondary side positive bus and a secondary side negative bus, and the left arm and the right arm are Each consists of two switching transistors connected in series. The connection point between the two switching transistors on the left arm and the connection between the two switching transistors on the right arm. The secondary side conversion circuit in which the first secondary side transformer coil and the second secondary side transformer coil are connected in series between the points, and the switching transistors of the primary side conversion circuit and the secondary side conversion circuit are switched. The first primary transformer coil and the first secondary transformer coil are wound around either the central leg or the leg at both ends of the core including the leg at both ends. The first secondary transformer coil and the second secondary transformer coil are wound around either one of the leg portions at both ends of the core, and the first primary transformer coil and the second 1 The secondary transformer coil is wound in the differential direction, the first secondary transformer coil and the second secondary transformer coil are wound in the differential direction, and a reactor coil is provided at the center leg of the core. And the end of which is wound It is connected to the middle point of the secondary transformer coil and the second primary transformer coil, and a reactor operation is performed by supplying an in-phase current to the first primary transformer coil and the second primary transformer coil. A transformer operation is performed by supplying a reverse phase current to the first primary transformer coil and the second primary transformer coil.

  According to the present invention, the substrate area and the core volume can be reduced, and the power conversion efficiency can be further improved. That is, by operating as a reactor with respect to changes in the common-mode current and operating as a transformer with respect to changes in the reverse-phase current, it is possible to function as an integrated magnetic element and reduce the substrate area and core volume. Also, when operating as a transformer, no current flows through the reactor coil at the center leg, so the AC resistance loss can be made zero. Furthermore, if the reactor coil is placed in a path where no reverse-phase current flows, the magnitude of the common-mode current flowing through the reactor coil is doubled, so that the inductance value similar to the conventional one can be realized even if the number of turns is halved. Eddy current loss due to magnetic field linkage can be halved.

It is a circuit block diagram of an embodiment. It is a cross-sectional view of the magnetic element of the embodiment. It is explanatory drawing which shows the flow of the electric current at the time of the reactor operation | movement of the magnetic element of embodiment. It is explanatory drawing which shows the flow of the electric current at the time of the trans | transformer operation | movement of the magnetic element of embodiment. It is explanatory drawing which shows the magnetic flux at the time of the trans | transformer operation | movement of the magnetic element of embodiment. It is a circuit diagram at the time of the transformer operation | movement of the magnetic element of embodiment. It is explanatory drawing which shows the magnetic flux at the time of the reactor operation | movement of the magnetic element of embodiment. It is a circuit diagram at the time of the reactor operation | movement of the magnetic element of embodiment. It is an equivalent circuit diagram of an embodiment. It is a block diagram of the magnetic element of embodiment. It is a voltage / current waveform diagram of each part of the embodiment. It is a graph of the simulation result which shows the conversion efficiency of embodiment. It is a cross-sectional view of a conventional magnetic element. It is explanatory drawing which shows the magnetic flux at the time of the trans | transformer operation | movement of the magnetic element of a prior art. It is a circuit diagram at the time of the transformer operation | movement of the magnetic element of a prior art. It is explanatory drawing which shows the magnetic flux at the time of the reactor operation | movement of the magnetic element of a prior art. It is a circuit diagram at the time of the reactor operation | movement of the magnetic element of a prior art. It is explanatory drawing which shows the flow of the electric current at the time of the reactor operation | movement of the magnetic element of a prior art. It is explanatory drawing which shows the flow of the electric current at the time of the trans | transformer operation | movement of the magnetic element of a prior art.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a basic circuit configuration diagram of a power conversion circuit system in the present embodiment. The power conversion circuit system includes a control circuit 100 and a power conversion circuit 120. The power conversion circuit 120 is a three-port multiport circuit capable of bidirectional power transmission between three DC power supplies using a magnetically coupled reactor.

  The multi-port circuit includes a port A and a port C in the primary side conversion circuit, and a port B and a port D in the secondary side conversion circuit.

  Between the positive bus of the primary side conversion circuit and the negative bus of the primary conversion circuit, the left arm consisting of switching transistors S1 and S2 connected in series with each other, and the switching transistors S3 and S4 connected in series with each other The left arm and the right arm are connected in parallel to each other to form a full bridge circuit. Port A is disposed between the positive and negative buses of the primary conversion circuit. The input / output voltage of port A is VA. Port C is arranged between the negative electrode bus of the primary side conversion circuit and the transformer. The input / output voltage of port C is set to VC.

  A magnetically coupled reactor (reactor coil) connected in series is connected between a connection point of the switching transistors S1 and S2 constituting the left arm and a connection point of the switching transistors S3 and S4 constituting the right arm. The primary windings (transformer coils) 12a and 12b of the transformer (transformer coil) are connected. That is, the magnetically coupled reactor and the primary side transformer coils 12a and 12b are connected to the midpoint between the two bidirectional chopper circuits.

  On the other hand, between the positive electrode bus and the negative electrode bus of the secondary side conversion circuit, there is a left arm composed of switching transistors S5 and S6 connected in series with each other and a right arm composed of switching transistors S7 and S8 connected in series with each other. The left arm and the right arm are connected in parallel to each other to form a full bridge circuit. Port B is disposed between the positive and negative buses of the secondary conversion circuit. The input / output voltage of port B is VB.

  The secondary windings (transformer coils) 14a and 14b of the transformer are connected between the connection point of the switching transistors S5 and S6 constituting the left arm and the connection point of the switching transistors S7 and S8 constituting the right arm. .

  The control circuit 100 sets various parameters for controlling the power conversion circuit 120 and performs switching control of the switching transistors S1 to S8 of the primary side conversion circuit and the secondary side conversion circuit. The control circuit 100 switches between a mode for performing power conversion between the two ports of the primary side conversion circuit and a mode for performing isolated power transmission between the primary side and the secondary side based on a mode signal from the outside. In terms of ports, the circuit is operated as a bidirectional isolated converter between port A and port B, and the circuit is operated as a bidirectional non-isolated converter between port A and port C. At this time, the magnetically coupled reactor uses a leakage inductance component to weaken the magnetic flux in the bidirectional insulated converter operation, and a sum component of the excitation inductance component and the leakage inductance component to strengthen the magnetic flux in the bidirectional non-insulated converter operation. Power transmission is performed using

  The insulated power transmission between the primary side conversion circuit and the secondary side conversion circuit is controlled by the phase difference φ of the switching cycle of the switching transistors S1 to S8 of the primary side conversion circuit and the secondary side conversion circuit.

When power is transmitted from the primary side conversion circuit to the secondary side conversion circuit, the phase difference φ is determined so that the primary side is in advance with respect to the secondary side. In contrast, when power is transmitted from the secondary side conversion circuit to the primary side conversion circuit, the phase difference φ is determined so that the primary side is delayed from the secondary side. For example, when power is transmitted from the secondary side conversion circuit to the primary side conversion circuit, the switching transistors S1 and S4 are turned on and S2 and S3 are turned off in the primary side conversion circuit. In the secondary conversion circuit, the switching transistors S5 and S8 are turned on, and S6 and S7 are turned off. In the secondary side conversion circuit,
S5 → Transformer secondary winding → S8
And current flows. In the primary side conversion circuit,
S4 → transformer primary winding → S1
And current flows.

  In the next period, the switching transistors S1, S4, S8 are turned on, and the others are turned off. Compared to the previous period, the switching transistor S5 changes from on to off, but when the switching transistor S5 of the secondary conversion circuit is turned off, current continues to flow through the diode connected in parallel to the switching transistor S6. The voltage across the secondary side drops to zero. Therefore, it is the on / off state of the switching transistor S5 that determines the voltage across the secondary side.

  In the next period, the switching transistors S1, S4, S6, and S8 are turned on, and the others are turned off.

  In the next period, the switching transistors S4, S6, and S8 are turned on, and the others are turned off. When the switching transistor S1 of the primary side conversion circuit transitions from on to off, current continues to flow through a diode connected in parallel to the switching transistor S1, and the voltage across the primary side is zero unless the switching transistor S2 is turned on. do not become. Therefore, it is the on / off state of the switching transistor S2 that determines the voltage across the primary side.

  A dead time of about several hundred nanoseconds to several microseconds may be provided so that the upper and lower switching transistors are not short-circuited. That is, a period in which both the switching transistors S1 and S2, S3 and S4, S5 and S6, and S7 and S8 are off may be provided.

  When the multi-port circuit of FIG. 1 is mounted on, for example, a high-bridge automobile or the like, a 48V auxiliary machine can be connected to port A, a 14V auxiliary machine can be connected to port C, and a main battery can be connected to port B.

  In the multi-port circuit as described above, a transformer operation by a transformer coil and a reactor operation by a reactor coil are required, and in a conventional magnetic element, as described above, a transformer coil is attached to the legs of both ends of a core having three legs. It arrange | positioned, arrange | positioned the reactor coil in the center leg part, it was made to operate | move as a reactor by sending an in-phase current to the reactor coil of a center leg part, and it was made to operate | move as a transformer by sending a reverse phase current.

  However, as described above, since the reverse-phase current also flows through the reactor coil, AC resistance loss occurs in the reactor coil, and conversion efficiency (power conversion efficiency) decreases.

  Therefore, in the present embodiment, the conversion efficiency is prevented from being lowered by arranging the reactor coil at the center leg in a path through which no reverse-phase current flows. Specifically, the transformer coil is wound in the differential direction around the legs at both ends of the core having three legs, and the reactor coil is wound around the center leg, and one end of the reactor coil is placed inside the transformer coil. Connect to the point. In other words, the reactor coil is wound from the middle point of the transformer coil and wound around the center leg.

  FIG. 2 shows a cross-sectional view of the magnetic element of this embodiment. Transformer coils 12a, 12b, 14a, 14b are arranged on both leg portions of the core 10 having three legs, and a reactor coil 16a is arranged on the center leg portion. In the figure, only the primary side reactor coil 16a is shown for simplification, but the secondary side reactor coil 16b may be similarly arranged. The transformer coils 12a and 12b are connected in series and in a differential direction, and the reactor coil 16a is connected to the midpoint Mu of the transformer coils 12a and 12b. The same applies to the secondary side.

  In the basic circuit configuration shown in FIG. 1, the reactor coil on the primary side is between the middle point Mu of the switching transistors S1 and S2 and the transformer coil 12a, and the middle point Mv of the switching transistors S3 and S4 and the transformer coil 12b. In this embodiment, the primary side reactor coil 16a is connected between the midpoint of the transformer coils 12a and 12b and the port C. The same applies to the secondary side. The equivalent circuit configuration of this embodiment will be further described later.

  FIG. 3 shows the flow of current during the reactor operation when the magnetic element shown in FIG. 2 is viewed from above. Transformer coils 12a and 12b are respectively arranged in the differential direction on the legs at both ends of core 10 having three legs, and current flows so as to be in phase with each other in the reactor operation. That is, the current from Mu flows through the left leg transformer coil 12a counterclockwise, and then flows through the center leg reactor coil 16a clockwise to port C. The current from Mv flows through the right leg transformer coil 12b counterclockwise, and then flows through the center leg reactor coil 16a clockwise to the port C. The magnetic flux generated by the transformer coils 12a and 12b on the left and right legs is in the direction from the back perpendicular to the paper surface, and the magnetic flux generated in the reactor coil 16a in the center leg is the direction from the front to the back perpendicular to the paper surface.

  On the other hand, FIG. 4 shows a current flow during the operation of the transformer when the magnetic element shown in FIG. 2 is viewed from above. The transformer coils 12a and 12b are respectively arranged in the differential direction on the legs at both ends of the core 10 having three legs, and current flows so as to be in opposite phases to each other in the transformer operation. That is, the current from Mu flows through the left leg transformer coil 12a counterclockwise, and then flows through the right leg transformer coil 12b clockwise. No current flows through the reactor coil 16a connected between the midpoint of the transformer coils 12a and 12b and the port C.

5A and 5B show magnetic flux and circuit diagrams in the transformer operation corresponding to FIG. Since the directions of the magnetic fluxes by the transformer coils 12a and 12b respectively disposed on the left and right legs are opposite to each other, the center legs cancel each other and do not operate as a reactor. For this reason, the reactor coil 16a is omitted in FIG. 5A. That is, the magnetic flux change is the same as that of an O-type core transformer without a central leg. The current is
Mu → transformer coil 12a → transformer coil 12b → Mv
There is no AC resistance loss because it does not flow through the reactor coil 16a.

6A and 6B show a magnetic flux and a circuit diagram in the reactor operation corresponding to FIG. Since the direction of the magnetic flux by the transformer coils 12a and 12b arranged on the left and right legs is the same, the magnetic flux does not cancel each other at the center leg, but the generated electromotive force is generated by the transformer coil 12a via the center tap. , 12b, the electromotive force of the entire coil becomes zero, and the coil does not operate as a transformer. For this reason, in FIG. 6A, the transformer coils 12a and 12b (and the transformer coils 14a and 14b) are omitted. In addition, the reactor has a characteristic that it is difficult to saturate because the magnetic flux changes in a path with a large magnetic resistance through the gap. The current is
Mu → transformer coil 12a → reactor coil 16a → C
And Mv → transformer coil 12b → reactor coil 16a → C
Therefore, a combined current of the current from Mu and the current from Mv flows through the reactor coil 16a.

  FIG. 7 shows an equivalent circuit diagram of the present embodiment. Unlike FIG. 1, the primary side reactor coil 16 a is connected between the midpoint of the transformer coils 12 a and 12 b and the port C. That is, one end of the transformer coil 12a is connected to the midpoint Mu of the switching transistors S1 and S2, and the other end is connected to the transformer coil 12b. One end of the transformer coil 12b is connected to the transformer coil 12a, and the other end is connected to the midpoint Mv of the switching transistors S3 and S4. One end of the reactor coil (magnetic coupling reactor coil) 16a is connected to the midpoint of the transformer coils 12a and 12b, and the other end is connected to the port C.

  FIG. 8 shows a wiring diagram of the magnetic element of this embodiment. The transformer coil 12a is wound around one of the leg portions at both ends of the core 10 having three legs, and the transformer coil 12b is wound around the other leg portion. The transformer coil 12a and the transformer coil 12b are connected in series and are connected in the differential direction. Moreover, the reactor coil 16a is wound around the center leg, and its end is connected to the midpoint of the transformer coils 12a and 12b.

  The same applies to the secondary side. The transformer coil 14a is wound around one of the leg portions at both ends of the core 10 having the three leg portions, and the transformer coil 14b is wound around the other leg portion. The transformer coil 14a and the transformer coil 14b are connected in series and are connected in the differential direction. Although not shown, reactor coil 16b is wound around the center leg portion as necessary, and its end portion is connected to the midpoint of transformer coils 14a and 14b.

  As described above, in this embodiment, the transformer coils are wound in the differential direction on the legs at both ends of the core having three legs (or the E-type core), and the reactor coil is provided at the midpoint of these transformer coils. It is connected and wound around the center leg, and it operates as a reactor for changes in the common-mode current and operates as a transformer for changes in the reverse-phase current. The core volume can be reduced. That is, by integrating the transformer and the reactor, the wiring space for connecting the magnetic elements is eliminated, so that the area occupied by the substrate of the magnetic elements can be reduced. Further, by integrating the transformer and the reactor, magnetic coupling is generated between the transformer coil and the reactor coil, and the inductance is increased. As a result, the core volume is reduced as compared with the case of using a magnetic element as a separate body. As a result of trial manufacture of the integrated magnetic element, the inventors of the present application have confirmed that the substrate area can be reduced by 40% and the core volume can be reduced by 20% compared to a separate case. Further, when operating as a transformer, no current flows through the reactor coil at the center leg, so that the AC resistance loss can be made zero. Also, if the reactor coil is placed in a path where no reverse-phase current flows, the magnitude of the common-mode current flowing through the reactor coil is doubled, so that the inductance value similar to the conventional one can be realized even if the number of turns is halved. Eddy current loss due to magnetic field linkage can be halved. As a result, the conversion efficiency can be improved by suppressing the AC resistance loss and the eddy current loss.

  In FIG. 9, when the voltage of port A is set to 48 V, the voltage of port B is set to 192 V, the voltage of port C is set to 14 V, the switching frequency is set to 125 kHz, and 250 W of power is transmitted from port B to port A The measured waveform of is shown. 9A shows a low voltage side voltage waveform V1, FIG. 9B shows a high voltage side voltage waveform V2, FIG. 9C shows a reactor current waveform iC, and FIG. 9D shows a transformer current waveform iU.

  The high-voltage side voltage waveform V2 is ahead of the phase of the low-voltage side voltage waveform V1, and is a waveform when electric power is transmitted from the high-voltage side to the low-voltage side. At this time, it can be seen that the reactor current waveform iC coincides with the boost current waveform and has no current distortion, so that it correctly functions as a reactor of the boost converter. In addition, the transformer current waveform iU is a waveform in which the alternating current waveform generated by the isolation converter operation is superimposed on the ripple current waveform generated by the boost converter operation, and since there is no current distortion, the transformer is operating correctly without magnetic saturation. I understand.

  FIG. 10 shows a trial calculation result by simulation of conversion efficiency (%) for each output (W). In the figure, a graph 150 indicated by a solid line is the conversion efficiency of the integrated magnetic element of the present embodiment, and a graph 200 indicated by a broken line is the conversion efficiency of the conventional integrated magnetic element. In this embodiment, since the AC resistance loss due to the reverse phase current is zero, the conversion efficiency is increased as compared with the conventional case. Further, the effect of improving the conversion efficiency becomes more remarkable as the output increases.

10 core, 12a, 12b primary transformer coil, 14a, 14b secondary transformer coil, 16a, 16b reactor coil, 100 control circuit, 120 power conversion circuit.

Claims (2)

A core with a central leg and legs on both ends;
A first primary transformer coil and a first secondary transformer coil wound around either of the leg portions at both ends;
A second primary transformer coil and a second secondary transformer coil wound around one of the leg portions at both ends;
With
The first primary transformer coil and the second primary transformer coil are connected in series and wound in a differential direction,
The first secondary transformer coil and the second secondary transformer coil are connected in series and wound in a differential direction,
A primary reactor coil is wound around the center leg of the core, and its end is connected to the midpoint of the first primary transformer coil and the second primary transformer coil,
A reactor operation is performed by supplying an in-phase current to the first primary transformer coil and the second primary transformer coil, and the first primary transformer coil and the second primary transformer coil are in reverse phase. A transformer-integrated magnetic element characterized in that a transformer operates when supplied with current. A primary side conversion circuit comprising a left arm and a right arm between a primary positive bus and a primary negative bus, each of the left and right arms comprising two switching transistors connected in series, A primary conversion circuit in which a first primary transformer coil and a second primary transformer coil are connected in series between a connection point of two switching transistors of an arm and a connection point of two switching transistors of a right arm. When,
A secondary side conversion circuit comprising a left arm and a right arm between a secondary positive bus and a secondary negative bus, the left arm and the right arm each comprising two switching transistors connected in series, A secondary conversion circuit in which a first secondary transformer coil and a second secondary transformer coil are connected in series between a connection point of two switching transistors of an arm and a connection point of two switching transistors of a right arm When,
A control circuit for controlling switching of the switching transistors of the primary side conversion circuit and the secondary side conversion circuit;
With
The first primary-side transformer coil and the first secondary-side transformer coil are wound around either the center leg part or the leg parts at both ends of the core including the leg parts at both ends,
The first secondary transformer coil and the second secondary transformer coil are wound around either one of the leg portions at both ends of the core,
The first primary transformer coil and the second primary transformer coil are wound in a differential direction,
The first secondary transformer coil and the second secondary transformer coil are wound in a differential direction,
A primary reactor coil is wound around the center leg of the core, and its end is connected to the midpoint of the first primary transformer coil and the second primary transformer coil,
A reactor operation is performed by supplying an in-phase current to the first primary transformer coil and the second primary transformer coil, and the first primary transformer coil and the second primary transformer coil are in reverse phase. A power conversion circuit system, which operates as a transformer when supplied with current.