JP2018014868A - Power conversion circuit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power conversion circuit which suppresses an increase in transformer core volume while guaranteeing a boost converter function and an insulation converter function, and can secure system robustness as well.SOLUTION: A power conversion circuit 10 includes a primary conversion circuit 10A, a secondary conversion circuit 10B, and a transformer for magnetically coupling the primary conversion circuit 10A and secondary conversion circuit 10. In the primary conversion circuit 10A, multiple modules of a module 1, a module 2, and so on comprising primary coils Tr1, Tr2, and so on of the transformer, multiple switch elements connected with the primary coils Tr1, Tr2, and so on of the transformer, and power sources are connected in series, and the primary coils Tr1, Tr2, and so on of at least two modules are wound reversely one another. During a module failure, all the switch elements of a failed module and modules having reverse winding are normally turned on.SELECTED DRAWING: Figure 1A

Description

  The present invention relates to a power conversion circuit.

  Conventionally, a power conversion circuit capable of performing power conversion between two input / output ports among a plurality of input / output ports has been proposed.

  Patent Document 1 describes a power conversion circuit that can perform boosting operation and insulated power transmission simultaneously in one circuit. Specifically, the power conversion includes a total of four input / output ports including two input / output ports of the primary side conversion circuit and two input / output ports of the secondary side conversion circuit magnetically coupled to the primary side conversion circuit. In the circuit, the primary side conversion circuit is connected to the primary side coil of the center tap type transformer that magnetically couples the primary side conversion circuit and the secondary side conversion circuit, and to both ends of the primary side coil of the transformer. A primary side full bridge circuit including a bridge portion having a primary side magnetic coupling reactor configured by magnetically coupling two reactors, and a first side provided between a positive electrode bus and a negative electrode bus of the primary side full bridge circuit. 1 input / output port, and a second input / output port provided between the negative bus of the primary side full bridge circuit and the center tap of the primary side coil of the transformer. Expression Tran Secondary full bridge including a bridge portion having a secondary side coil of the power source and a secondary side magnetic coupling reactor configured by magnetically coupling two reactors connected to both ends of the secondary side coil of the transformer Circuit, a third input / output port provided between the positive and negative buses of the secondary full bridge circuit, and the negative bus of the secondary full bridge circuit and the center tap of the secondary coil of the transformer And a fourth input / output port. In the primary side conversion circuit or the secondary side conversion circuit, it operates as a boost converter by duty ratio (duty) modulation, and between the primary side conversion circuit and the secondary side conversion circuit, it operates as an isolation converter by phase modulation. Power transmission.

JP 2011-193713 A

  FIG. 6 shows an example of a system using the conventional power conversion circuit 10. In this system, the main battery 12, the inverter circuit 14, and the motor 16 are connected to the primary side conversion circuit of the power conversion circuit 10, and the auxiliary machine is connected to the secondary side conversion circuit. The electric power from the main battery 12 is boosted by the primary side conversion circuit and supplied to the inverter circuit 14, converted into three-phase AC power by the inverter circuit 14, and supplied to the motor 16. The power from the main battery 12 is transmitted from the primary side conversion circuit to the secondary side conversion circuit and supplied to the auxiliary machine 18.

  However, if the command value voltage matches the voltage of the main battery 12 when the primary side conversion circuit functions as a boost converter, the switch element of the upper arm of the primary side conversion circuit is always turned on, so the primary side conversion is performed. There is a problem that insulation power transmission from the circuit to the secondary side conversion circuit becomes impossible. This is because the insulated power transmission is performed by the switching phase difference between the primary side conversion circuit and the secondary side conversion circuit. In addition, the switching frequency must be set to a slower frequency in accordance with the switching frequency of the booster circuit for the main engine, and there is a problem that the transformer core volume is increased.

  FIG. 7A and FIG. 7B show one circuit configuration for solving these problems. 7A shows the overall configuration, and FIG. 7B shows the configuration of module 1 in FIG. 7A. The other modules have the same configuration.

  In the primary side conversion circuit 10A and the secondary side conversion circuit 10B constituting the power conversion circuit 10, the primary side conversion circuit 10A which is the high voltage side is connected to a plurality of modules 1, module 2, module 3,. By using multiple series connection and lowering the switching element withstand voltage of the main unit side circuit, the switching frequency can be increased to the same level as the auxiliary converter for auxiliary machinery, and the increase of the transformer core volume can be prevented. Further, by arranging battery cells in parallel as the main battery 12 so as to have a voltage lower than that in the case of FIG. 6, it is possible to always perform switching in the entire operation range and to transmit insulated power. In FIG. 7B, a fuse 13 for separating the battery cell 12 from the circuit is connected between the battery cell 12 of the main battery and the primary coil of the transformer.

  However, in such a circuit configuration, the duty is extremely high at the time of maximum boosting, and the volume of the output capacitor is increased. Further, since the current that is larger than that in the case of FIG. 6 flows through the reactor as the input voltage is lowered, the efficiency decreases due to an increase in the volume of the reactor core and an increase in the copper loss. Furthermore, since a plurality of modules 1, modules 2,..., Module N are connected in series, the boost converter function for the main engine and the isolated converter function for the auxiliary machine are lost only when one module fails. Therefore, there is a problem that the system robustness is lowered.

  An object of the present invention is to provide a power conversion circuit that can suppress an increase in the volume of a transformer core while ensuring a boost converter function and an insulating converter function, and can also ensure system robustness.

  The present invention includes a primary side conversion circuit, a secondary side conversion circuit, a transformer that magnetically couples the primary side conversion circuit and the secondary side conversion circuit, and the primary side conversion circuit is a primary side of the transformer. A plurality of modules including a coil, a plurality of switch elements connected to a primary coil of a transformer, and a power source are connected in series, and primary coils of at least two modules are reversely wound with each other. Circuit.

  In one embodiment of the present invention, the module includes a first switch element and a second switch element connected in series with each other, a third switch element and a fourth switch element connected in series with each other, a first switch element and a first switch element. A primary coil of a transformer connected between a midpoint of the two switch elements, a midpoint of the third switch element and the fourth switch element, a positive electrode is connected to the primary coil of the transformer, and a negative electrode is the first A power source connected to the negative electrode side of the two switch elements and the fourth switch element is provided.

  In another embodiment of the present invention, the module includes a first hybrid transformer, a first flying capacitor connected in series to the first hybrid transformer, and a first hybrid connected in series to the first hybrid transformer and the first flying capacitor. A first booster circuit including a first switch element and a third switch element, and a second switch element connected in parallel to the first hybrid transformer and the first flying capacitor, a second hybrid transformer, and a second hybrid transformer in series. Connected in parallel to the second flying capacitor, the fourth switch element and the sixth switch element connected in series to the second hybrid transformer and the second flying capacitor, and the second hybrid transformer and the second flying capacitor. And a fifth switch element 1 of a transformer connected between the booster circuit, the midpoint of the first switch element and the first flying capacitor of the first booster circuit, and the midpoint of the fourth switch element of the second booster circuit and the second flying capacitor. A secondary coil and a power source having a positive electrode connected to the first hybrid transformer of the first booster circuit and a second hybrid transformer of the second booster circuit, and a negative electrode connected to the negative electrode side of the third switch element and the sixth switch element Prepare.

  In yet another embodiment of the invention, the module comprises a fuse that disconnects the power source from the circuit.

  In still another embodiment of the present invention, when any of a plurality of modules fails, all the switch elements of the failed module and the modules that are reversely wound with the primary coil of the failed module are always turned on. And a control circuit that controls the switch elements of other modules to be turned on and off.

  According to the present invention, it is possible to suppress an increase in the volume of the transformer core while ensuring the boosting converter function and the insulating converter function, and to ensure system robustness.

It is a circuit block diagram of 1st Embodiment. It is a circuit block diagram of the module of 1st Embodiment. It is explanatory drawing at the time of the module failure of 1st Embodiment. It is a circuit block diagram of the module of 2nd Embodiment. It is an operation | movement timing chart of the module of 2nd Embodiment. It is a circuit block diagram of 2nd Embodiment. It is a circuit block diagram of the module of 2nd Embodiment. It is a conventional circuit block diagram. It is a multi-series connection block diagram of a plurality of modules. It is a circuit block diagram of the module of FIG. 7A.

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

<First Embodiment>
1A and 1B show a circuit configuration of a power conversion circuit 10 in the first embodiment. FIG. 1A shows the overall configuration of the power conversion circuit 10, and FIG. 1B shows the circuit configuration of the module 1 in FIG. 1A.

  The power conversion circuit 10 includes a primary side conversion circuit 10A and a secondary side conversion circuit 10B, and the primary side conversion circuit 10A includes a plurality of modules 1, modules 2,... Configured. An inverter circuit 14 and a motor 16 are connected to the primary side conversion circuit 10A as a load (see FIG. 6). In the figure, the inverter circuit 14 is shown as a load resistor. The auxiliary machine 18 is connected to the secondary side conversion circuit 10B as a load (see FIG. 6). In the figure, the auxiliary machine 18 is shown as a load resistance.

  As shown in FIG. 1B, the module 1 of the primary side conversion circuit 10A is configured by magnetically coupling a primary side coil Tr1 of a transformer and two reactors connected to both ends of the primary side coil Tr1 of the transformer. A full bridge circuit having a primary magnetically coupled reactor, a main battery (battery cell) 12, and a fuse 13. An output capacitor C1 is connected to the module 1.

  The full bridge circuit includes an upper left arm, a lower left arm, an upper right arm, and a lower right arm, and includes switch elements (MOS transistors) S1 to S4 and feedback diodes connected in parallel to the switch elements. The A left arm with an upper left arm and a lower left arm connected in series is attached between the positive and negative buses, and a right arm with an upper right arm and a lower right arm connected in series is attached in parallel with the left arm. It is done. One end of the magnetically coupled reactor and the primary coil Tr1 of the transformer is connected to the midpoint of the switch elements S1 and S2. The other end of the primary coil Tr1 of the transformer is connected to the midpoint of the switch elements S3 and S4 via a magnetic coupling reactor. A positive electrode of the main battery (battery cell) 12 is connected to the middle point of the primary coil Tr1 of the transformer via a fuse 13, and a negative electrode of the main battery (battery cell 12) is connected to the negative electrode bus. The other modules have the same configuration, the module 2 includes a primary coil Tr2 of the transformer, and the module N includes a primary coil TrN of the transformer.

  Module 1, module 2,..., Module N are connected in series with each other at respective output capacitors C1, C2,.

  The secondary conversion circuit 10B includes switch elements S7 and S8, a secondary coil of a transformer, and a current smoothing reactor. The primary side coils Tr1, Tr2,... TrN of the plurality of modules 1, module 2,..., Module N of the primary side conversion circuit 10A and the secondary side coils of the secondary side conversion circuit 10B Is also magnetically coupled through the transformer core.

  The control circuit 50 controls on / off of the switch elements of the primary side conversion circuit 10A and the secondary side conversion circuit 10B. The control circuit 50 is constituted by a microcomputer having a CPU, a ROM, a RAM, and an input / output interface. The control circuit 50 calculates a duty command value and a phase difference command value in order to perform switching control of the switch element.

  1A and 1B, the primary side conversion circuit 10A, which is the high voltage side, is connected in a multi-series connection of a plurality of modules 1, module 2, module 3,... Module N, and the switch element withstand voltage of the main unit side circuit is reduced. By lowering, the switching frequency can be increased to the same level as that of the auxiliary converter for isolated machinery, and the increase of the transformer core volume can be prevented. Further, by arranging the battery cells in parallel as the main battery 12 so as to have a voltage lower than that in the case of FIG. 6, it is possible to always switch in the entire operation range and to transmit the insulated power.

  On the other hand, the configuration of FIG. 1A and FIG. 1B is different from the configuration of FIG. 7A and FIG. 7B in that, among the primary side coils Tr1, Tr2,. This is the reverse winding. Specifically, Tr1 and Tr2 are reversely wound with each other, Tr2 and Tr3 are reversely wound with each other, and Tr3 and Tr4 are reversely wound with each other. In general, the primary coil Tri of the i-th module and the primary coil Tri + 1 of the (i + 1) -th module adjacent thereto are reversely wound with each other (i = 1, 2, 3,..., N).

  In such a circuit configuration, as shown in FIG. 2, a case is assumed in which one of the modules, for example, the circuit of the module 1 has failed. In the figure, the module 1 is marked with a cross, indicating that it has failed. The control circuit 50 always turns on all the switch elements of the failed module 1, and also always turns on all the switch elements of the module 1, for example, the module 2, which are in a reverse winding relationship with the primary coil Tr1 of the module 1. Further, the control circuit 50 controls the phase difference between the primary side conversion circuit 10A and the secondary side conversion circuit 10B by turning on and off the switch elements in the same manner as in the normal mode for the remaining modules.

  Then, the transformer excitation voltage by the module 1 other than the failed module 1 and the module 2 that is reversely wound with the module 1 is canceled out by the modules 1 and 2 that are reversely wound with each other. The insulating converter function from the secondary side conversion circuit 10A to the secondary side conversion circuit 10B is maintained. That is, even if the module 1 fails, it is possible to transmit insulated power from other modules except the modules 1 and 2 to the auxiliary machine.

  Further, as shown in FIG. 1B, a fuse 13 is provided between the primary coil Tr1 of the transformer and the main battery (battery cell) 12, and all of the failed module 1 and the module 2 wound in the reverse direction are provided. By always turning on the switch element, the main battery (battery cell) 12 and the circuit are separated in the module 1 and the module 2, and the main battery (battery cell) 12 can be protected.

  Furthermore, the charges of the output capacitors C1 and C2 connected to the module 1 and the module 2 become zero by the on operation of all the switch elements in these modules, and the main motor current flows through the switch elements that are all on. The main engine boost converter function by other modules excluding modules 1 and 2 is also maintained.

  When the module 1 fails, all the switch elements of the module 4 (or the module 6 or the like) may be turned on instead of the module 2.

  As described above, even if one of the modules fails, the boost converter function and the isolated converter function can be maintained, and the robustness of the system can be improved as compared with the configurations of FIGS. 7A and 7B.

Second Embodiment
FIG. 3 shows a basic circuit configuration of the power conversion circuit 10 of the present embodiment. Also in the present embodiment, the primary conversion circuit 10A is configured by connecting a plurality of modules in series, but the circuit configuration of the modules is different from the configuration of the first embodiment. FIG. 3 shows a circuit configuration in one module.

  The module of this embodiment is configured by paralleling two high booster circuits using a hybrid transformer and a flying capacitor (these are referred to as a U-phase booster circuit and a V-phase booster circuit). A hybrid transformer is a transformer that performs both a transformer operation and a reactor operation. By using a hybrid transformer, it is possible to obtain a high step-up ratio without setting the switching duty to an extremely high value.

  The U-phase booster circuit functions as a first booster circuit, and includes a first hybrid transformer, a switch element S1, a switch element S2, a switch element S3, and a first flying capacitor Cfu. The first hybrid transformer includes a transformer coil Lp and a transformer coil Ls, and performs a transformer operation and a reactor operation. The transformer coil Lp is connected to a main battery (battery cell) 12. The transformer coil Ls and the first flying capacitor Cfu are connected in series, and the switch elements S1 and S3 are connected in series to the transformer coil Ls and the first flying capacitor Cfu connected in series. The switch element S3 is connected in parallel to the transformer coil Ls and the first flying capacitor Cfu connected in series. A free-wheeling diode is connected in parallel to each of the switch elements S1, S2, and S3.

  The V-phase booster circuit functions as a second booster circuit, and includes a second hybrid transformer, a switch element S4, a switch element S5, a switch element S6, and a second flying capacitor Cfv. The second hybrid transformer includes a transformer coil Lp and a transformer coil Ls, and performs a transformer operation and a reactor operation. The transformer coil Lp is connected to a main battery (battery cell) 12. The transformer coil Ls and the second flying capacitor Cfv are connected in series, and the switch elements S4 and S6 are connected in series to the transformer coil Ls and the second flying capacitor Cfv connected in series. The switch element S5 is connected in parallel to the transformer coil Ls and the second flying capacitor Cfv connected in series. A free-wheeling diode is connected in parallel to each of the switch elements S4, S5, and S6.

  One end of the primary coil Tr1 of the transformer is connected to the middle point of the switching element S1 of the U-phase boost circuit and the first flying capacitor Cfu, and the other end is switched to the switching element S4 of the V-phase boost circuit and the second flying capacitor Cfv. Connected to the midpoint.

  The switching elements S1 to S6 of the U-phase booster circuit and the V-phase booster circuit are on / off controlled by the control circuit 50. The main boost converter operation is performed with the switching duty of the U-phase boost circuit and the V-phase boost circuit, and the isolation converter operation is performed with the phase difference between the U-phase and the V-phase.

  The secondary conversion circuit 10B is the same as that of the first embodiment, and includes two switch elements S7 and S8, a secondary coil of the transformer, and a current smoothing reactor.

  FIG. 4 shows an operation waveform timing chart when power is simultaneously transmitted from the main battery (battery cell) 12 to the main load 14 and the auxiliary load 18.

  In the figure, the ON / OFF operation timing of the switch elements S1 to S8, the voltage VTr1 and current iTr1 of the primary coil Tr1 of the transformer, and the currents iLpu, iLsu, V flowing through the transformer coils Lp, Ls of the first hybrid transformer of the U-phase booster circuit. The time change of the electric current io which flows the electric current iLpv and iLsv which flow through the transformer coils Lp and Ls of the 2nd hybrid transformer of a phase booster circuit, and the secondary side conversion circuit 10B is shown. D represents the on-duty of the switch elements S2 and S3, and T represents the switching period. φ indicates the phase difference between the U phase and the V phase.

  The switch element S1, S2, and S3 are in an inverted relationship, and when the switch element S1 is turned on, the switch elements S2 and S3 are turned off. These switch elements are turned on and off at a duty determined by the boost ratio. The switch element S4 and S5 and S6 are also in the same inversion relationship.

  When switch element S1 is turned off and switch elements S2 and S3 are turned on, main battery (battery cell) 12 is connected to first hybrid transformer and first flying capacitor Cfu, and main hybrid battery (battery cell) 12 is connected to first hybrid transformer. To charge the first flying capacitor Cfu. That is, power is supplied to the first flying capacitor Cfu by the transformer operation of the first hybrid transformer. At the same time, energy is accumulated in the magnetic element by the reactor operation of the first hybrid transformer. Currents iLp and iLs flow through the transformer coils Lp and Ls of the first hybrid transformer.

  Next, when the switch element S1 is turned on and the switch elements S2 and S3 are turned off, the main battery (battery cell) 12, the transformer coils Lp and Ls, the first flying capacitor Cfu, and the switch element S1 are connected in series with each other, and the transformer The current flows back to the free-wheeling diode connected in parallel to the semiconductor switch element S2 until the currents flowing through the coils Lp and Ls become equal.

  Thereafter, when the main battery (battery cell) 12 and the first flying capacitor Cfu are in series, power is supplied to the output capacitor C1 side. The same applies to the V phase.

  On the other hand, the voltage VTr1 applied to the primary coil Tr1 of the transformer is controlled by the phase difference φ between the U phase and the V phase.

The switch elements S7 and S8 of the secondary side conversion circuit 10B are expressed by logical expressions S7 = S2 + S5.
S8 = S1 + S6
ON / OFF operation is performed so that That is, the switch element S7 is turned on / off by the logical sum of the switch elements S2 and S5, and the switch element S8 is turned on / off by the logical sum of the switch elements S1 and S6. As a result, the switch elements S7 and S8 perform a synchronous rectification function during power transmission from the primary side conversion circuit 10A to the secondary side conversion circuit 10B, and from the secondary side conversion circuit 10B to the primary side conversion circuit 10A. The transformer excitation function is executed during power transmission.

  In the circuit shown in FIG. 3, since it is not necessary to increase the duty extremely even in the high boost ratio operation, the output current ripple can be reduced and the size of the output capacitor can be reduced.

  5A and 5B show a circuit configuration of the power conversion circuit of the present embodiment. 5A shows the overall configuration of the power conversion circuit 10, and FIG. 5B shows the circuit configuration of the module 1 in FIG. 5A. Also in the present embodiment, two adjacent primary coils of the transformer primary coils Tr1, Tr2,... TrN are reversely wound. Specifically, Tr1 and Tr2 are reversely wound, Tr21 and Tr3 are reversely wound, and Tr3 and Tr4 are reversely wound. In general, the primary coil Tri of the i-th module and the primary coil Tri + 1 of the (i + 1) -th module adjacent thereto are reversely wound.

  In such a circuit configuration, a case is assumed in which one of the modules, for example, the circuit of module 1 fails. The control circuit 50 turns on all the switch elements of the failed module 1, and also turns on all the switch elements of the module 1, for example, the module 2, which are in a reverse winding relationship with the primary coil Tr1 of the module 1. Further, the control circuit 50 controls the phase difference by turning on and off the switch elements in the same manner as usual for the remaining modules.

  Then, the transformer excitation voltage by the module 1 other than the failed module 1 and the module 2 that is reversely wound with the module 1 is canceled out by the modules 1 and 2 that are reversely wound with each other. The insulating converter function from the secondary side conversion circuit 10A to the secondary side conversion circuit 10B is maintained.

  Further, as shown in FIG. 5B, by providing a fuse 13 between the hybrid transformer of the U-phase booster circuit and the hybrid transformer of the V-phase booster circuit and the main battery (battery cell) 12, the failed module 1 and this When all the switch elements of the reversely wound module 2 are turned on, the main battery (battery cell) 12 and the circuit are separated from each other in the modules 1 and 2, and the main battery (battery cell) 12 can be protected.

  Further, the charges of the output capacitors connected to the modules 1 and 2 become zero when all the switch elements are turned on, and the main motor current flows through the switch elements that are all turned on. Function is also maintained.

  Further, the inventors have reduced the volume of the circuit configuration of the present embodiment by 46% compared to the circuit configuration of the first embodiment because the direct-current magnetic flux flowing through the magnetic element core and the effective current flowing through the output capacitor are reduced. It has been confirmed that it can be reduced.

  Furthermore, the inventors have lost the loss when operating the circuit so that the total of the output voltage is 650 V and the total of the output power is 27 kW, in which 28 circuits each having two parallel 6 V cells as inputs are connected in series. Was calculated. In this embodiment, the current flowing through the switch elements S1 and S4 can be regarded as a series boost from the total voltage of the input voltage and the flying capacitor to the output voltage as compared with the first embodiment, so that the current value can be lowered. . For this reason, a switch element loss can be made small. Further, while a large current flows through the reactor of the first embodiment, a large current flows only through the low-voltage side coil of the hybrid transformer in the present embodiment, so that the conduction loss of the reactor winding can also be reduced. It has been confirmed that the circuit loss can be reduced by 17% by these synergistic effects.

  As described above, in the second embodiment, not only the robustness of the system can be improved as in the first embodiment, but also the main battery (battery cell) 12 and the flying can be supplied while the flying capacitor is fed by the transformer operation of the hybrid transformer. Since the series boosting by the capacitor is performed, the magnetic flux generated in the core can be reduced. Further, since the switching duty does not need to be extremely increased even in the high boosting operation, the output current ripple can be reduced, and as a result, the output capacitor size can be reduced. Further, since the conduction loss of the upper arm is reduced and the conduction loss of the reactor winding is reduced, the circuit efficiency can be improved.

  In the first and second embodiments, among the multiple modules connected in series, the primary side coils of the transformers of adjacent modules are reversely wound, but the transformer core is common and the primary side coil It suffices if there are at least two modules whose winding directions are opposite to each other.

  Further, the number of modules in the first embodiment and the second embodiment is arbitrary, and modules can be added later if necessary.

  In the first embodiment and the second embodiment, the main boost converter function and the auxiliary insulation converter function have been described. However, since a plurality of modules are connected in series, the main battery (battery cell) 12 of each module. It is also possible to equalize the cells by operating the switch elements in accordance with the SOC (charging state).

  In the first embodiment and the second embodiment, the main battery (battery cell) 12 is connected to the circuit in each module. For example, the main battery (battery cell) 12 is heated by heat generated from the circuit at a low temperature. The temperature of the main battery (battery cell) 12 can also be adjusted.

Further, in the first and second embodiments, only the auxiliary machine 18 is connected to the secondary side conversion circuit 10B, but a plurality of secondary side conversion circuits 10B are magnetically coupled to the primary side conversion circuit 10A. ,
An output voltage of a certain secondary side conversion circuit may be 48V, an output voltage of another secondary side conversion circuit may be 12V, and a photovoltaic power generation device may be connected to another secondary side conversion circuit.

DESCRIPTION OF SYMBOLS 10 Power conversion circuit, 10A Primary side conversion circuit, 10B Secondary side conversion circuit, 12 Main machine battery (battery cell), 13 Fuse, 14 Inverter circuit (main machine resistance), 16 Motor, 18 Auxiliary machine (auxiliary machine resistance).

Claims (5)

A primary side conversion circuit;
A secondary conversion circuit;
A transformer for magnetically coupling the primary side conversion circuit and the secondary side conversion circuit;
With
In the primary side conversion circuit, a plurality of modules including a primary coil of a transformer and a plurality of switch elements and a power source connected to the primary coil of the transformer are connected in series.
The power conversion circuit, wherein primary coils of at least two modules are reversely wound with each other. Module is
A first switch element and a second switch element connected in series with each other;
A third switch element and a fourth switch element connected in series with each other;
A primary coil of a transformer connected between a midpoint of the first switch element and the second switch element, and a midpoint of the third switch element and the fourth switch element;
A power source having a positive electrode connected to the primary coil of the transformer and a negative electrode connected to the negative side of the second switch element and the fourth switch element;
The power conversion circuit according to claim 1, further comprising: Module is
A first hybrid transformer; a first flying capacitor connected in series to the first hybrid transformer; a first switch element and a third switch element connected in series to the first hybrid transformer and the first flying capacitor; A first booster circuit comprising a hybrid transformer and a second switch element connected in parallel to the first flying capacitor;
A second hybrid transformer; a second flying capacitor connected in series to the second hybrid transformer; a fourth switch element and a sixth switch element connected in series to the second hybrid transformer and the second flying capacitor; A second booster circuit comprising a fifth transformer element connected in parallel to the hybrid transformer and the second flying capacitor;
A primary coil of a transformer connected between the first switch element of the first booster circuit and the midpoint of the first flying capacitor, and the fourth switch element of the second booster circuit and the midpoint of the second flying capacitor; ,
A power source having a positive electrode connected to the first hybrid transformer of the first booster circuit and a second hybrid transformer of the second booster circuit, and a negative electrode connected to the negative electrode side of the third switch element and the sixth switch element;
The power conversion circuit according to claim 1, further comprising: The power conversion circuit according to claim 2, wherein the module includes a fuse that disconnects the power source from the circuit. When one of the modules fails, all the switch elements of the module that is reversely wound with the failed module and the primary coil of the failed module are always turned on, and the switch elements of the other modules are turned on. A control circuit for controlling on / off operation;
The power conversion circuit according to claim 2, comprising:

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