Isolated Power Supply

Abstract

To provide an insulation power supply device which can improve controllability of output voltage of each transformer.SOLUTION: An insulation power supply device 100 includes: a plurality of transformers 60a to 60e; and a control switch 51 for controlling current flowing from a low voltage battery 42 to respective input windings 61a to 61e, and supplies power from the low voltage battery 42 to respective drive circuits DCH, DCL, and DUH to DWL by switching on / off the control switch 51. The insulation power supply device 100 includes: first to fifth feedback windings LRa to LRe which have first to fifth feedback windings 63a to 63e, and in which one of both ends of the respective feedback windings 63a to 63e is connected to ground and a first end is connected to the other end of both the ends of the respective feedback windings 63a to 63e; an input side common winding Ls to which a second end of the respective feedback windings LRa to LRe is connected; and power supply IC50 which turns on / off the control switch 51 on the basis of a voltage value of the input side common winding Ls.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to an isolated power supply device. [Background technology]

[0002] Known insulated power supplies are those that supply power from a DC power supply to a plurality of power supply targets while electrically insulating the DC power supply from the plurality of power supply targets using a transformer. For example, Patent Document 1 describes an insulated power supply that includes a plurality of transformers and a control switch that controls the current flowing through an input winding corresponding to each transformer.

[0003] Each input winding is connected to a DC power supply, and the output side of each transformer is connected to a corresponding power supply target. When a control switch is turned on, power is supplied from the DC power supply to each input winding. This causes magnetic energy to accumulate in each transformer. On the other hand, when the control switch is turned off, power supply from the DC power supply to each input winding is stopped. During this time, power is supplied from each transformer to the power supply target corresponding to the output side of each transformer. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 6817298 Summary of the Invention [Problem to be solved by the invention]

[0005] If there is variation in the size of the load of each power supply target, there is a concern that the controllability of the output voltage of each transformer may decrease.

[0006] Specifically, when variations occur in the load magnitudes of the power supply targets, the output voltage of a transformer corresponding to a power supply target with a small load may increase compared to a transformer corresponding to a power supply target with a large load due to an excessive supply of magnetic energy. On the other hand, the output voltage of a transformer corresponding to a power supply target with a large load may decrease compared to a transformer corresponding to a power supply target with a small load due to an insufficient supply of magnetic energy. In other words, when variations occur in the load magnitudes of the power supply targets, variations may occur in the output voltage of each transformer.

[0007] Here, it is conceivable that the control switch may be turned on and off based on the output voltage of one of the transformers. In this case, the control switch of the transformer that is the control target is turned on and off so that the output voltage becomes the target output voltage. On the other hand, the output voltage of the transformer that is not the control target basically changes by the difference between the output voltage of the transformer that is the control target and the target output voltage. Therefore, if there is variation in the output voltage of each transformer, there is a concern that the output voltage of the transformer that is not the control target may become excessively high or excessively low relative to the target output voltage, thereby reducing the controllability of the output voltage.

[0008] The present invention has been made in view of the above circumstances, and has as its object to provide an isolated power supply device that can improve the controllability of the output voltage of each transformer. [Means for solving the problem]

[0009] The present invention provides an isolated power supply device including a plurality of transformers each having an input winding and a core around which the input winding is wound, Each of the input windings is connected to a DC power supply, and an output side of each of the transformers is connected to a power supply target corresponding to each of the transformers, At least two of the transformers have control windings that are magnetically coupled to the input windings via the cores, a control switch that, when turned on, supplies power from the DC power supply to each of the input windings, and, when turned off, stops the supply of power from the DC power supply to each of the input windings; control wiring provided corresponding to each of the control windings; a common wiring; a first end of each of the control windings is connected to ground; a second end of each of the control windings is connected to a first end of the corresponding control wiring; a second end of each of the control lines is connected to the common line; A control unit is provided that turns on and off the control switch based on the voltage value of the common line.

[0010] The loads of the power supply targets may vary. In this case, the transformer corresponding to the power supply targets with small loads may receive an excessive supply of magnetic energy, while the transformer corresponding to the power supply targets with large loads may receive an insufficient supply of magnetic energy, resulting in variations in the output voltages of the transformers. In this case, if the control switch is turned on and off based on the output voltage of one of the transformers, there is a concern that the controllability of the output voltages of the other transformers may be reduced.

[0011] Therefore, in the present invention, at least two of the transformers have control windings that are magnetically coupled to the input windings via cores around which the input windings are wound. A first end of each control winding is connected to ground. A second end of each control winding is connected to a common wiring via a corresponding control wiring. In this configuration, a closed circuit is formed including each control winding, each control wiring, and the common wiring. In this case, when a current flows through the closed circuit, magnetic energy stored in each transformer having a control winding is exchanged between the transformers. Specifically, magnetic energy is transferred from a transformer with high magnetic energy to a transformer with low magnetic energy. This prevents the magnetic energy stored in each transformer from becoming excessive or insufficient. As a result, variation in the output voltage of each transformer can be reduced.

[0012] Furthermore, the control switches are turned on and off based on the voltage value of the common wiring. As a result, voltages generated in many control windings are used to control the control switches, compared to when the control switches are turned on and off based on the voltage generated in any one control winding of each transformer. This makes it possible to reduce the number of transformers that are not subject to control.

[0013] As described above, according to the present invention, it is possible to reduce the number of transformers that are not controlled while reducing the variation in the output voltage of each transformer. As a result, it is possible to prevent the output voltage of each transformer from becoming excessively high or low, and ultimately to improve the controllability of the output voltage of each transformer. [Brief explanation of the drawings]

[0014] [Figure 1] 1 is an overall configuration diagram of a motor control system according to a first embodiment. [Figure 2] FIG. 1 is a diagram showing an isolated power supply device. [Figure 3] FIG. 4 is a diagram showing an insulated power supply device according to a modified example of the first embodiment. [Figure 4] FIG. 4 is a diagram showing an insulated power supply device according to a modified example of the first embodiment. [Figure 5] FIG. 4 is a diagram showing an insulated power supply device according to a modified example of the first embodiment. [Figure 6] FIG. 4 is a diagram showing an insulated power supply device according to a modified example of the first embodiment. [Figure 7] FIG. 4 is a diagram showing an insulated power supply device according to a modified example of the first embodiment. [Figure 8] FIG. 4 is a diagram showing an insulated power supply device according to a modified example of the first embodiment. [Figure 9] FIG. 10 is a diagram showing an insulated power supply device according to a second embodiment. [Figure 10] FIG. 10 is a diagram showing an insulated power supply device according to a modified example of the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0015] First Embodiment An insulated power supply according to a first embodiment of the present invention will now be described with reference to the drawings. The insulated power supply according to this embodiment is installed in, for example, an electric vehicle equipped with only a motor generator of the two components that are the motor generator and the engine.

[0016] As shown in Fig. 1, the motor control system includes a motor generator 10, an inverter 12, a boost converter 30, and a control device 40. The motor generator 10 is connected to drive wheels via a power split mechanism (not shown). The motor generator 10 is connected to the inverter 12 and functions as a vehicle main engine, etc. The inverter 12 is a three-phase inverter and is connected to a high-voltage battery 20 (e.g., a lithium-ion secondary battery or a nickel-metal hydride secondary battery) via the boost converter 30.

[0017] The boost converter 30 includes a smoothing capacitor 31, a reactor 32, an upper-arm boost switch SCH, and a lower-arm boost switch SCL. In this embodiment, voltage-controlled semiconductor switches, specifically IGBTs, are used as the upper-arm boost switch SCH and the lower-arm boost switch SCL. A freewheel diode is connected in anti-parallel to each of the switches SCH and SCL.

[0018] The emitter of the upper-arm boost switch SCH is connected to the collector of the lower-arm boost switch SCL. A first terminal of a smoothing capacitor 31 is connected to the collector of the upper-arm boost switch SCH, and a second terminal of the smoothing capacitor 31 and the negative terminal of the high-voltage battery 20 are connected to the emitter of the lower-arm boost switch SCL. In other words, a series connection of the boost switches SCH and SCL is connected in parallel to the smoothing capacitor 31. The emitter of the upper-arm boost switch SCH and the collector of the lower-arm boost switch SCL are connected to the positive terminal of the high-voltage battery 20 via a reactor 32. The boost converter 30 boosts the output voltage of the high-voltage battery 20 by turning on and off the boost switches SCH and SCL.

[0019] The inverter 12 includes three phases of series-connected upper-arm switches SUH, SVH, and SWH and lower-arm switches SUL, SVL, and SWL. In this embodiment, each of the switches SUH to SWL is a voltage-controlled semiconductor switch, specifically an IGBT. A freewheeling diode is connected in antiparallel to each of the switches SUH to SWL.

[0020] The emitter of the U-phase upper arm switch SUH is connected to the collector of the U-phase lower arm switch SUL. The junction between the U-phase upper arm switch SUH and the U-phase lower arm switch SUL is connected to the U-phase input terminal of the motor generator 10. The emitter of the V-phase upper arm switch SVH is connected to the collector of the V-phase lower arm switch SVL. The junction between the V-phase upper arm switch SVH and the V-phase lower arm switch SVL is connected to the V-phase input terminal of the motor generator 10. The emitter of the W-phase upper arm switch SWH is connected to the collector of the W-phase lower arm switch SWL. The junction between the W-phase upper arm switch SWH and the W-phase lower arm switch SWL is connected to the W-phase input terminal of the motor generator 10.

[0021] The collectors of the upper arm switches SUH to SWH are connected by a positive bus 13 such as a bus bar. The positive bus 13 is connected to the collector of the upper arm step-up switch SCH and a first end of the smoothing capacitor 31. The emitters of the lower arm switches SUL to SWL are connected by a negative bus 14 such as a bus bar. The negative bus 14 is connected to the emitter of the lower arm step-up switch SCL, a second end of the smoothing capacitor 31, and the negative terminal of the high-voltage battery 20.

[0022] The control device 40 is a microcomputer driven by power supplied from a low-voltage battery 42 serving as a DC power supply. The control device 40 operates the inverter 12 and the boost converter 30 to control the torque of the motor generator 10 to a command torque Trq*. More specifically, the control device 40 generates operation signals GUH-GWL to turn on and off the switches SUH-SWL that constitute the inverter 12, and outputs these signals to drive circuits for the switches SUH-SWL. The control device 40 generates operation signals GCH, GCH to turn on and off the switches SCH, SCL that constitute the boost converter 30, and outputs these signals to drive circuits for the switches SCH, SCL.

[0023] The low-voltage battery 42 is a storage battery, such as a lead-acid battery, whose output voltage is lower than the output voltage of the high-voltage battery 20. In this embodiment, the low-voltage battery 42 corresponds to the "DC power supply."

[0024] The interface unit 44 has a function of transmitting signals between a high-voltage area including the motor generator 10, inverter 12, boost converter 30, and high-voltage battery 20 and a low-voltage area including the control device 40 and low-voltage battery 42, while electrically insulating these systems from each other. The interface unit 44 is, for example, a photocoupler.

[0025] Next, the insulated power supply 100 will be described with reference to Fig. 2. The insulated power supply 100 has a function of supplying power to drive circuits DCH, DCL, DUH to DWL that drive the switches SCH, SCL, SUH to SWL, while providing insulation between a high voltage region and a low voltage region. In this embodiment, the insulated power supply 100 is a flyback type switching power supply.

[0026] The isolated power supply 100 includes a power supply IC 50 and a control switch 51. The power supply IC 50 and the control switch 51 are provided in a low-voltage region. The power supply IC 50 turns the control switch 51 on and off. The control switch 51 is a voltage-controlled semiconductor switch, and more specifically, an N-channel MOSFET.

[0027] The isolated power supply 100 includes an upper arm transformer that supplies power to the upper arm drive circuits DCH, DUH, DVH, and DWH, and a lower arm transformer that supplies power to the lower arm drive circuits DCL, DUL, DVL, and DWL. The upper arm transformers are provided individually for the upper arm switches SCH, SUH, SVH, and SWH. The lower arm transformer is provided as a common transformer for the lower arm switches SCL, SUL, SVL, and SWL.

[0028] Specifically, the upper arm transformers are first to fourth transformers 60a, 60b, 60c, and 60d, and the lower arm transformer is a fifth transformer 60e. The first transformer 60a supplies power to the boost upper arm drive circuit DCH, and the second transformer 60b supplies power to the U-phase upper arm drive circuit DUH. The third transformer 60c supplies power to the V-phase upper arm drive circuit DVH, and the fourth transformer 60d supplies power to the W-phase upper arm drive circuit DWH. The fifth transformer 60e supplies power to the lower arm drive circuits DCL, DUL, DVL, and DWL. In this embodiment, each of the drive circuits DCH, DCL, DUH, and DWL corresponds to a "power supply target."

[0029] The first transformer 60a includes a first input winding 61a, a first output winding 62a, and a first feedback winding 63a. The first transformer 60a includes a common core around which the windings 61a, 62a, and 63a are wound, and the windings 61a, 62a, and 63a are magnetically coupled by the common core.

[0030] Similar to the first transformer 60a, the second transformer 60b includes a second input winding 61b, a second output winding 62b, and a second feedback winding 63b that are magnetically coupled by a common core. Similar to the first transformer 60a, the third transformer 60c includes a third input winding 61c, a third output winding 62c, and a third feedback winding 63c that are magnetically coupled by a common core. Similar to the first transformer 60a, the fourth transformer 60d includes a fourth input winding 61d, a fourth output winding 62d, and a fourth feedback winding 63d that are magnetically coupled by a common core. Similar to the first transformer 60a, the fifth transformer 60e includes a fifth input winding 61e, a fifth output winding 62e, and a fifth feedback winding 63e that are magnetically coupled by a common core.

[0031] The input windings 61a to 61e and the feedback windings 63a to 63e are provided in the low voltage region, and the output windings 62a to 62e are provided in the high voltage region.

[0032] Each of the transformers 60a to 60e is provided with a plurality of terminals. The output terminals of the first to fifth transformers 60a to 60e are connected to corresponding first to fifth output windings 62a to 62e.

[0033] The first terminal T1a of the first transformer 60a is connected to the second terminal T2a of the first transformer 60a via the first input winding 61a. The third terminal T3a of the first transformer 60a is connected to the fourth terminal T4a of the first transformer 60a via the first feedback winding 63a. When the potential of the first terminal T1a is higher than that of the second terminal T2a of the first transformer 60a, an induced voltage is generated in the first feedback winding 63a such that the potential of the fourth terminal T4a of the first transformer 60a is higher than that of the third terminal T3a.

[0034] The first terminal T1b of the second transformer 60b is connected to the second terminal T2b of the second transformer 60b via the second input winding 61b. The third terminal T3b of the second transformer 60b is connected to the fourth terminal T4b of the second transformer 60b via the second feedback winding 63b. When the potential of the first terminal T1b is higher than that of the second terminal T2b of the second transformer 60b, an induced voltage is generated in the second feedback winding 63b such that the potential of the fourth terminal T4b of the second transformer 60b is higher than that of the third terminal T3b.

[0035] The first terminal T1c of the third transformer 60c is connected to the second terminal T2c of the third transformer 60c via the third input winding 61c. The third terminal T3c of the third transformer 60c is connected to the fourth terminal T4c of the third transformer 60c via the third feedback winding 63c. When the potential of the first terminal T1c is higher than that of the second terminal T2c of the third transformer 60c, an induced voltage is generated in the third feedback winding 63c such that the potential of the fourth terminal T4c of the third transformer 60c is higher than that of the third terminal T3c.

[0036] The first terminal T1d of the fourth transformer 60d is connected to the second terminal T2d of the fourth transformer 60d via a fourth input winding 61d. The third terminal T3d of the fourth transformer 60d is connected to the fourth terminal T4d of the fourth transformer 60d via a fourth feedback winding 63d. When the potential of the first terminal T1d of the fourth transformer 60d is higher than that of the second terminal T2d, an induced voltage is generated in the fourth feedback winding 63d such that the potential of the fourth terminal T4d is higher than that of the third terminal T3d of the fourth transformer 60d.

[0037] The first terminal T1e of the fifth transformer 60e is connected to the second terminal T2e of the fifth transformer 60e via a fifth input winding 61e. The third terminal T3e of the fifth transformer 60e is connected to the fourth terminal T4e of the fifth transformer 60e via a fifth feedback winding 63e. When the potential of the first terminal T1e relative to the second terminal T2e of the fifth transformer 60e becomes higher, an induced voltage is generated in the fifth feedback winding 63e such that the potential of the fourth terminal T4e of the fifth transformer 60e is higher than the potential of the third terminal T3e.

[0038] The output terminal of the first transformer 60a is connected to the boost upper arm drive circuit DCH via a first output diode 64a and a first output capacitor 65a. The output terminal of the second transformer 60b is connected to the U-phase upper arm drive circuit DUH via a second output diode 64b and a second output capacitor 65b. The output terminal of the third transformer 60c is connected to the V-phase upper arm drive circuit DVH via a third output diode 64c and a third output capacitor 65c. The output terminal of the fourth transformer 60d is connected to the W-phase upper arm drive circuit DWH via a fourth output diode 64d and a fourth output capacitor 65d. The output terminal of the fifth transformer 60e is connected to the lower arm drive circuits DCL, DUL, DVL, and DWL via a fifth output diode 64e and a fifth output capacitor 65e.

[0039] The first terminals T1a to T1e of each of the transformers 60a to 60e are connected to the positive terminal of the low-voltage battery 42 via wiring. More specifically, the first terminal T1e of the fifth transformer 60e is connected to the positive terminal of the low-voltage battery 42 via a fifth positive wiring LPe. The first terminal T1a of the first transformer 60a is connected to the fifth positive wiring LPe via a first positive wiring LPa. That is, the first terminal T1a of the first transformer 60a is connected to the positive terminal of the low-voltage battery 42 via the first and fifth positive wirings LPa and LPe. The first terminals T1b to T1d of the second to fourth transformers 60b to 60d are connected to the fifth positive wiring LPe via the corresponding second to fourth positive wirings LPb to LPd, similar to the first terminal T1a of the first transformer 60a. That is, the first terminals T1b to T1d of the second to fourth transformers 60b to 60d are connected to the positive terminal of the low-voltage battery 42 via the fifth positive wiring LPe and the corresponding second to fourth positive wirings LPb to LPd. The negative side of the low-voltage battery 42 is connected to ground.

[0040] The second terminals T2a to T2e of each of the transformers 60a to 60e are connected to the drain of the control switch 51 via wiring. More specifically, the second terminal T2a of the first transformer 60a is connected to the drain of the control switch 51 via the first negative wiring LNa. The second terminals T2b to T2d of the second to fifth transformers 60b to 60e are connected to the first negative wiring LNa via the corresponding second to fifth negative wirings LNb to LNd. In other words, the second terminals T2b to T2d of the second to fifth transformers 60b to 60e are connected to the drain of the control switch 51 via the first negative wiring LNa and the corresponding second to fifth negative wirings LNb to LNd. The source of the control switch 51 is connected to ground.

[0041] The third terminals T3a to T3e of the first to fifth transformers 60a to 60e are connected to the input-side common wiring Ls via the corresponding first to fifth feedback wirings LRa to LRe. The feedback wirings LRa to LRe and the input-side common wiring Ls are provided in a low-voltage region.

[0042] A first feedback diode 71a is provided on the first feedback wiring LRa. The anode of the first feedback diode 71a is connected to the third terminal T3a of the first transformer 60a, and the cathode of the first feedback diode 71a is connected to the input-side common wiring Ls. A second feedback diode 71b is provided on the second feedback wiring LRb. The anode of the second feedback diode 71b is connected to the third terminal T3b of the second transformer 60b, and the cathode of the second feedback diode 71b is connected to the input-side common wiring Ls.

[0043] A third feedback diode 71c is provided on the third feedback wiring LRc. The anode of the third feedback diode 71c is connected to the third terminal T3c of the third transformer 60c, and the cathode of the third feedback diode 71c is connected to the input-side common wiring Ls. A fourth feedback diode 71d is provided on the fourth feedback wiring LRd. The anode of the fourth feedback diode 71d is connected to the third terminal T3d of the fourth transformer 60d, and the cathode of the fourth feedback diode 71d is connected to the input-side common wiring Ls. A fifth feedback diode 71e is provided on the fifth feedback wiring LRe. The anode of the fifth feedback diode 71e is connected to the third terminal T3e of the fifth transformer 60e, and the cathode of the fifth feedback diode 71e is connected to the input-side common wiring Ls.

[0044] The fourth terminal T4a of the first transformer 60a is connected to ground via the first ground wiring LGa. As in the case of the first transformer 60a, the fourth terminals T4b to T4e of the second to fifth transformers 60b to 60e are connected to ground via the corresponding second to fifth ground wirings LGb to LGe.

[0045] The isolated power supply 100 includes first to fifth feedback capacitors 72a to 72e. The first feedback capacitor 72a connects the cathode of the first feedback diode 71a to the first ground wiring LGa. As with the first feedback capacitor 72a, the second to fifth feedback capacitors 72b to 72e connect the cathodes of the corresponding second to fifth feedback diodes 71b to 71e to the corresponding second to fifth ground wirings LGb to LGe.

[0046] The insulated power supply 100 includes bleeder resistors. The bleeder resistors are provided to adjust the magnitude of the load connected to each of the transformers 60a to 60e and are responsible for reducing variations in voltage generated in each of the feedback windings 63a to 63e. In this embodiment, the insulated power supply 100 includes first to fourth bleeder resistors 73a to 73d as upper-arm bleeder resistors and a fifth bleeder resistor 73e as a lower-arm bleeder resistor. The resistance value of the fifth bleeder resistor 73e is set smaller than the resistance values ​​of the first to fourth bleeder resistors 73a to 73d.

[0047] A first end of the first bleeder resistor 73a is connected to the first feedback wiring LRa, and a second end of the first bleeder resistor 73a is connected to ground. As with the first bleeder resistor 73a, first ends of the second to fifth bleeder resistors 73b to 73e are connected to the corresponding second to fifth feedback wirings LRb to LRe, and second ends of the second to fifth bleeder resistors 73b to 73e are connected to ground. The first ends of the bleeder resistors 73a to 73e are connected to the cathodes of the corresponding feedback diodes 71a to 71e.

[0048] The power supply IC 50 is a single integrated circuit that turns on and off a control switch 51 to supply power from the low-voltage battery 42 to each of the drive circuits DCH, DCL, DUH to DWL while electrically insulating the low-voltage battery 42 from each of the drive circuits DCH, DCL, DUH to DWL. At this time, the power supply IC 50 turns on and off the control switch 51 to feedback-control the feedback control value Vfb to a target value Vtg. In this embodiment, the power supply IC 50 sets a duty ratio Ton / Tsw where Tsw is one switching period of the control switch 51 and Ton is the on-time. Then, the power supply IC 50 outputs an operation signal according to the set duty ratio to the gate of the control switch 51. In this embodiment, the power supply IC 50 corresponds to the "control unit."

[0049] In this embodiment, the feedback control value Vfb is feedback-controlled to the target value Vtg, and the control switch 51 is turned on and off to change the voltage generated in each output winding 62a to 62e by an amount corresponding to the deviation value between the feedback control value Vfb and the target value Vtg.

[0050] When the control switch 51 is turned on, power is supplied from the low-voltage battery 42 to each of the input windings 61a to 61e. During this time, an induced voltage is generated in the first feedback winding 63a such that the potential at the fourth terminal T4a of the first transformer 60a becomes higher than the potential at the third terminal T3a. In this case, the first feedback diode 71a restricts current flow through the first feedback winding 63a, and magnetic energy is accumulated in the first transformer 60a. As with the first feedback winding 63a, the first output diode 64a restricts current flow through the first output winding 62a.

[0051] As with the first transformer 60a, when the control switch 51 is turned on, magnetic energy is accumulated in the second to fifth transformers 60b to 60e. Specifically, when the control switch 51 is turned on, an induced voltage is generated in the second feedback winding 63b such that the potential at the fourth terminal T4b of the second transformer 60b is higher than the third terminal T3b. In this case, the second feedback diode 71b prevents current from flowing through the second feedback winding 63b, and magnetic energy is accumulated in the second transformer 60b. When the control switch 51 is turned on, an induced voltage is generated in the third feedback winding 63c such that the potential at the fourth terminal T4c of the third transformer 60c is higher than the third terminal T3c. In this case, the third feedback diode 71c prevents current from flowing through the third feedback winding 63c, and magnetic energy is accumulated in the third transformer 60c.

[0052] When the control switch 51 is turned on, an induced voltage is generated in the fourth feedback winding 63d such that the potential at the fourth terminal T4d of the fourth transformer 60d is higher than the third terminal T3d. In this case, the fourth feedback diode 71d prevents current from flowing through the fourth feedback winding 63d, and magnetic energy is stored in the fourth transformer 60d. When the control switch 51 is turned on, an induced voltage is generated in the fifth feedback winding 63e such that the potential at the fourth terminal T4e of the fifth transformer 60e is higher than the third terminal T3e. In this case, the fifth feedback diode 71e prevents current from flowing through the fifth feedback winding 63e, and magnetic energy is stored in the fifth transformer 60e.

[0053] When the control switch 51 is turned on, the flow of current to the second to fifth output windings 62b to 62e is restricted by the corresponding second to fifth output diodes 64b to 64e, as in the case of the second to fifth feedback windings 63b to 63e.

[0054] On the other hand, when the control switch 51 is turned off, power supply from the low-voltage battery 42 to each of the input windings 61a to 61e is stopped. During this time, an induced voltage is generated in the first feedback winding 63a such that the potential at the third terminal T3a of the first transformer 60a is higher than the potential at the fourth terminal T4a. This causes a current to flow through the first feedback winding 63a. Similarly to the first feedback winding 63a, a current also flows through the first output winding 62a, and power is supplied to the boost upper arm driver circuit DCH.

[0055] As in the case of the first transformer 60a, when the control switch 51 is turned off, a current flows through the second to fifth feedback windings 63b to 63e. Specifically, when the control switch 51 is turned off, an induced voltage is generated in the second feedback winding 63b such that the potential at the third terminal T3b of the second transformer 60b is higher than the potential at the fourth terminal T4b. This causes a current to flow through the second feedback winding 63b. Also, as in the case of the second feedback winding 63b, a current flows through the second output winding 62b, and power is supplied to the corresponding U-phase upper arm drive circuit DUH.

[0056] When the control switch 51 is turned off, an induced voltage is generated in the third feedback winding 63c such that the potential at the third terminal T3c of the third transformer 60c is higher than the potential at the fourth terminal T4c. This causes a current to flow through the third feedback winding 63c. Similarly to the case of the third feedback winding 63c, a current also flows through the third output winding 62c, and power is supplied to the corresponding V-phase upper arm drive circuit DVH.

[0057] When the control switch 51 is turned off, an induced voltage is generated in the fourth feedback winding 63d such that the potential at the third terminal T3d of the fourth transformer 60d is higher than the potential at the fourth terminal T4d. This causes a current to flow through the fourth feedback winding 63d. Similarly to the fourth feedback winding 63d, a current also flows through the fourth output winding 62d, and power is supplied to the corresponding W-phase upper arm drive circuit DWH.

[0058] When the control switch 51 is turned off, an induced voltage is generated in the fifth feedback winding 63e such that the potential at the third terminal T3e of the fifth transformer 60e is higher than the potential at the fourth terminal T4e. This causes a current to flow through the fifth feedback winding 63e. Similarly to the fifth feedback winding 63e, a current also flows through the fifth output winding 62e, and power is supplied to the corresponding lower arm drive circuits DCL, DUL, DVL, and DWL.

[0059] However, if variations occur in the magnitude of the load of each of the drive circuits DCH, DCL, DUH to DWL, there is a concern that the controllability of the output voltage of each of the transformers 60a to 60e may be reduced.

[0060] Specifically, there may be situations in which the drive conditions of the switches SUH-SWL of the inverter 12 and the switches SCH, SCL of the boost converter 30 are different. For example, there may be a situation in which the switches SCH, SCL of the boost converter 30 are not driven, but the switches SUH-SWL of the inverter 12 are driven. In this case, the magnitude of the load on the boost upper and lower arm drive circuits DCH, DCL is smaller than the magnitude of the load on the upper and lower arm drive circuits DUH-DWL of each phase. As a result, for example, the first transformer 60a corresponding to the boost upper arm drive circuit DCH may receive an excess supply of magnetic energy compared to the second to fourth transformers 60b-60d corresponding to the upper arm drive circuits DUH-DWH of each phase, resulting in a rise in output voltage.

[0061] Furthermore, for example, among the switches SUH-SWL of the inverter 12, only the U- and V-phase upper and lower arm switches SUH, SVH, SUL, and SVL may be driven. In this case, the loads on the U- and V-phase upper and lower arm drive circuits DUH, DVH, DUL, and DVL are greater than the loads on the W-phase upper and lower arm drive circuits DWH and DWL. As a result, for example, the second and third transformers 60b and 60c corresponding to the U- and V-phase upper arm drive circuits DUH and DVH may receive less magnetic energy than the fourth transformer 60d corresponding to the W-phase upper arm drive circuit DWH, resulting in a lower output voltage. In this way, when the loads on the drive circuits DCH, DCL, and DUH-DWL vary, the output voltages of the transformers 60a-60e may vary.

[0062] Unlike the present embodiment, the control switch 51 may be turned on and off based on the output voltage of one of the transformers 60a-60e. In this case, the control switch 51 is turned on and off so that the output voltage of the transformer to be controlled among the transformers 60a-60e becomes the target output voltage. On the other hand, the output voltage of the transformer not to be controlled among the transformers 60a-60e changes by the difference between the output voltage of the transformer to be controlled and the target output voltage. Therefore, in a situation where there is a possibility of variation in the output voltages of the transformers 60a-60e, there is a concern that the output voltage of the transformer not to be controlled among the transformers 60a-60e may become excessively high or low relative to the target output voltage. Note that, for example, the output voltage of each transformer 60a-60e is the voltage generated in each output winding 62a-62e, and the target output voltage is set within a voltage range defined by the upper and lower limit voltages of the voltage generated in each output winding 62a-62e.

[0063] Therefore, in this embodiment, the isolated power supply 100 uses the voltages generated in the feedback windings 63a to 63e to turn on and off the control switch 51. More specifically, the isolated power supply 100 includes a first voltage dividing resistor 84 and a second voltage dividing resistor 85. A first end of the first voltage dividing resistor 84 is connected to the input-side common wiring Ls, and a second end of the first voltage dividing resistor 84 is connected to a first end of the second voltage dividing resistor 85. A second end of the second voltage dividing resistor 85 is connected to ground. The connection point between the second end of the first voltage dividing resistor 84 and the first end of the second voltage dividing resistor 85 is connected to the power supply IC 50.

[0064] The power supply IC 50 turns the control switch 51 on and off based on the voltage value of the input-side common wiring Ls. In this embodiment, the power supply IC 50 obtains the voltage division values ​​of the first and second voltage dividing resistors 84, 85. The power supply IC 50 sets the duty ratio of the control switch 51 based on the obtained voltage division values. As a result, voltages generated in many feedback windings are used to set the duty ratio of the control switch 51, compared to when the duty ratio of the control switch 51 is set based on the voltage generated in the feedback winding of any one of the transformers 60a to 60e.

[0065] In this embodiment, magnetic energy stored in each of the transformers 60a-60e is exchanged between the transformers 60a-60e. Specifically, in the configuration of the insulated power supply 100 described above, a closed circuit is formed that includes each of the feedback windings 63a-63e, each of the feedback wirings LRa-LRe, and the input-side common wiring Ls. In this case, when a current flows through the closed circuit, magnetic energy is transferred between the transformers 60a-60e from a transformer with high magnetic energy to a transformer with low magnetic energy. This prevents the magnetic energy stored in each of the transformers 60a-60e from becoming excessive or insufficient. This reduces variations in the output voltage of each of the transformers 60a-60e.

[0066] In this embodiment, feedback diodes 71a to 71e and feedback capacitors 72a to 72e are provided corresponding to the feedback windings 63a to 63e. The current output from the third terminals T3a to T3e of the transformers 60a to 60e is rectified by the corresponding feedback diodes 71a to 71e, and the corresponding feedback capacitors 72a to 72e are charged. In this case, current flows in a closed circuit including the feedback windings 63a to 63e, the feedback wirings LRa to LRe, and the input-side common wiring Ls by transferring charge accumulated in the feedback capacitors 72a to 72e. As a result, magnetic energy is transferred between the transformers 60a to 60e.

[0067] It is considered that a closed circuit is formed including each input winding 61a to 61e, each positive electrode wiring LPa to LPe, each negative electrode wiring LNa to LNe, the control switch 51, and the low-voltage battery 42, and that magnetic energy is exchanged between each transformer 60a to 60e as a result of current flowing through the closed circuit.

[0068] However, in this case, there is a concern that a large current flows through the positive wirings LPa-LPe and the negative wirings LNa-LNe to supply power from the low-voltage battery 42 to the transformers 60a-60e, resulting in an increased voltage drop in the formed closed circuit. Furthermore, the current flowing through the wirings LPa-LPe and LNa-LNe in response to the on / off of the control switch 51 increases the rate of change of the current flowing through the wirings LPa-LPe and LNa-LNe. Therefore, there is a concern that the inductance components of the input windings 61a-61e make it difficult for current to flow through the closed circuit including the input windings 61a-61e. Therefore, in this embodiment, a closed circuit is formed that includes the feedback windings 63a-63e, the feedback wirings LRa-LRe, and the input-side common wiring Ls. In this embodiment, the feedback windings 63a-63e correspond to "control windings," and the feedback wirings LRa-LRe correspond to "control wiring."

[0069] According to the present embodiment described above in detail, the following effects can be obtained.

[0070] According to this embodiment, the variation in the output voltage of each of the transformers 60a to 60e is reduced, and the number of transformers that are not subject to control is reduced compared to when a feedback winding is provided in only one of the transformers 60a to 60e. As a result, it is possible to prevent the output voltage of each of the transformers 60a to 60e from becoming excessively high or low, and ultimately to improve the controllability of the output voltage of each of the transformers 60a to 60e.

[0071] It is conceivable that the control switch 51 is turned on and off based on the voltage generated in each of the output windings 62a to 62e. However, the power supply IC 50 is provided in a low-voltage region, and the output windings 62a to 62e are provided in a high-voltage region. Therefore, in order to transmit the voltage generated in each of the output windings 62a to 62e to the power supply IC 50, it is necessary to add an insulating transmission unit that transmits the voltage value of each of the output windings 62a to 62e to the power supply IC 50 while electrically insulating each of the output windings 62a to 62e from the power supply IC 50.

[0072] In this regard, in this embodiment, feedback windings 63a to 63e are provided corresponding to the transformers 60a to 60e. The third terminals T3a to T3e of the transformers 60a to 60e are connected to the input-side common wiring Ls via the corresponding feedback wirings LRa to LRe. The voltage value of the input-side common wiring Ls is then transmitted to the power supply IC 50. This eliminates the need for an additional insulating transmission section, thereby preventing an increase in the number of components in the isolated power supply device 100. At the same time, this embodiment improves the controllability of the output voltage of each of the transformers 60a to 60e, as described above. In other words, it is possible to improve the controllability of the output voltage of each of the transformers 60a to 60e while preventing an increase in the number of components in the isolated power supply device 100.

[0073] When a current flows through a closed circuit including the feedback windings 63a to 63e, the feedback wirings LRa to LRe, and the input-side common wiring Ls, there is a concern that the inductance components of the feedback windings 63a to 63e may make it difficult for the current to flow through the closed circuit, which may result in insufficient transfer of the magnetic energy stored in the transformers 60a to 60e.

[0074] In this regard, according to this embodiment, current flows in a closed circuit including the feedback windings 63a-63e, the feedback wirings LRa-LRe, and the input-side common wiring Ls by transferring charge stored in the feedback capacitors 72a-72e. This transfers magnetic energy stored in the transformers 60a-60e. Therefore, magnetic energy can be transferred appropriately between the transformers 60a-60e while preventing current from flowing through the closed circuit due to the inductance components of the feedback windings 63a-63e.

[0075] A configuration in which a voltage dividing resistor is provided corresponding to each of the feedback windings 63a to 63e is also considered. In this configuration, a voltage dividing resistor is connected to each of the feedback wirings LRa to LRe. In this case, a closed circuit is formed including each of the feedback windings 63a to 63e, each of the feedback wirings LRa to LRe, the input-side common wiring Ls, and the voltage dividing resistor, which may make it difficult for current to flow through the closed circuit. In this regard, according to this embodiment, the input-side common wiring Ls is connected to the first end of the first voltage dividing resistor 84. As a result, a closed circuit is formed including each of the feedback windings 63a to 63e, each of the feedback wirings LRa to LRe, and the input-side common wiring Ls without passing through the first and second voltage dividing resistors 84 and 85. Therefore, compared to a configuration in which a voltage dividing resistor is provided corresponding to each of the feedback windings 63a to 63e, it is possible to prevent current from flowing difficultly through the closed circuit.

[0076] It is considered that magnetic energy stored in each of the transformers 60a to 60e is transferred when a current flows through a closed circuit including a bleeder resistor, which is a heat-generating component. Here, it is desirable to arrange the bleeder resistor near each of the feedback windings 63a to 63e to prevent the path of the closed circuit including the bleeder resistor from becoming too long. In this regard, each of the feedback windings 63a to 63e is connected to the input-side common wiring Ls via each of the feedback wirings LRa to LRe. Therefore, it is considered that the bleeder resistor can be arranged closer to each of the feedback windings 63a to 63e when connected to each of the feedback wirings LRa to LRe, which are directly connected to each of the feedback windings 63a to 63e, than when connected to the input-side common wiring Ls.

[0077] Therefore, in this embodiment, the bleeder resistors 73a to 73e are connected to the corresponding feedback wirings LRa to LRe, which allows the bleeder resistors 73a to 73e to be arranged while preventing the path of the closed circuit including the bleeder resistors 73a to 73e from becoming long.

[0078] In this embodiment, bleeder resistors are provided corresponding to the feedback windings 63a to 63e. Specifically, bleeder resistors 73a to 73e are connected to the feedback wirings LRa to LRe, respectively. This allows the bleeder resistors 73a to 73e, which are heat-generating components, to be distributed.

[0079] The first to fourth transformers 60a to 60d are provided individually corresponding to the upper arm switches SCH, SUH, SVH, and SWH, and the fifth transformer 60e is provided as a common transformer for the lower arm switches SCL, SUL, SVL, and SWL. In this configuration, the magnitude of the load connected to the fifth transformer 60e is considered to be larger than the magnitude of the load connected to the first to fourth transformers 60a to 60d.

[0080] In this regard, in this embodiment, the resistance value of the fifth bleeder resistor 73e is set smaller than the resistance values ​​of the first to fourth bleeder resistors 73a to 73d. This makes it possible to accurately suppress imbalance between the magnitude of the load connected to the fifth transformer 60e and the magnitude of the load connected to the first to fourth transformers 60a to 60d. As a result, it is possible to accurately reduce variations in the voltages generated in the feedback windings 63a to 63e.

[0081] <Modification of the first embodiment> The upper arm transformers may be provided as a common transformer for each of the upper arm switches SCH, SUH, SVH, and SWH, instead of being provided individually for each of the upper arm switches SCH, SUH, SVH, and SWH.

[0082] Specifically, as shown in Fig. 3, the upper arm transformer is a sixth transformer 60f. The sixth transformer 60f supplies power to the upper arm drive circuits DCH, DUH to DWH. The sixth transformer 60f includes a sixth input winding 61f and a sixth feedback winding 63f. The sixth transformer 60f includes a common core around which the sixth input winding 61f, the output windings 62a to 62d, and the sixth feedback winding 63f are wound, and the windings 61f, 62a to 62d, and 63f are magnetically coupled by the common core. Note that in Fig. 3, the same components as those shown in Fig. 2 are denoted by the same reference numerals for convenience.

[0083] The sixth transformer 60f has first to fourth terminals T1f to T4f. The first terminal T1f of the sixth transformer 60f is connected to the second terminal T2f of the sixth transformer 60f via a sixth input winding 61f. The third terminal T3f of the sixth transformer 60f is connected to the fourth terminal T4f of the sixth transformer 60f via a sixth feedback winding 63f. When the potential of the first terminal T1f relative to the second terminal T2f of the sixth transformer 60f is higher, an induced voltage is generated in the sixth feedback winding 63f such that the potential of the fourth terminal T4f of the sixth transformer 60f is higher than the third terminal T3f.

[0084] The first terminal T1f of the sixth transformer 60f is connected to the positive terminal of the low-voltage battery 42 via the first and fifth positive wirings LPa and LPe. The second terminal T2f of the sixth transformer 60f is connected to the drain of the control switch 51 via the first negative wiring LNa. The third terminal T3f of the sixth transformer 60f is connected to the input-side common wiring Ls via the fourth feedback wiring LRd. The fourth terminal T4f of the sixth transformer 60f is connected to ground via the fourth ground wiring LGd.

[0085] According to this embodiment, the sixth transformer 60f is provided as the upper arm transformer. This allows for a reduction in the number of transformers provided as upper arm transformers compared to a configuration in which the first to fourth transformers 60a to 60d are provided. At the same time, while suppressing variations in the output voltages of the fifth and sixth transformers 60e and 60f, the number of transformers that are not subject to control can be reduced compared to a configuration in which a feedback winding is provided in only one of the fifth and sixth transformers 60e and 60f. As a result, the controllability of the output voltages of the fifth and sixth transformers 60e and 60f can be improved while reducing the number of transformers provided as upper arm transformers.

[0086] Instead of providing the feedback windings 63a to 63e corresponding to each of the transformers 60a to 60e, feedback windings may be provided corresponding to at least two of the transformers 60a to 60e.

[0087] For example, as shown in Fig. 4, among the transformers 60a to 60e, first, third, fourth, and fifth feedback windings 63a, 63c, 63d, and 63e may be provided corresponding to the first, third, fourth, and fifth transformers 60a, 60c, 60d, and 60e, respectively, and the second transformer 60b may not be provided with a feedback winding. Note that in Fig. 4, the same components as those shown in Fig. 2 are denoted by the same reference numerals for convenience.

[0088] According to this embodiment, the number of transformers provided with feedback windings is reduced compared to a configuration in which a feedback winding 63a-63e is provided corresponding to each of the transformers 60a-60e. This allows for a reduction in the number of components in the isolated power supply 100 compared to a configuration in which a feedback winding 63a-63e is provided corresponding to each of the transformers 60a-60e. At the same time, while suppressing changes in the output voltages of the first, third, fourth, and fifth transformers 60a, 60c, 60d, and 60e, the number of transformers that are not subject to control can be reduced compared to a configuration in which a feedback winding is provided only on one of the transformers 60a-60e. As a result, the controllability of the output voltages of the first, third, fourth, and fifth transformers 60a, 60c, 60d, and 60e can be improved while reducing the number of components in the isolated power supply 100.

[0089] Instead of the configuration in which the first and second voltage dividing resistors 84, 85 are connected to the input side common wiring Ls, a configuration in which voltage dividing resistors are provided corresponding to the feedback wirings LRa to LRe may be adopted.

[0090] For example, as shown in Fig. 5, an insulated power supply 100 includes third to twelfth voltage dividing resistors 86 to 95. In Fig. 5, the same components as those shown in Fig. 2 are denoted by the same reference numerals for convenience.

[0091] The third voltage divider resistor 86 and the fourth voltage divider resistor 87 are provided corresponding to the first feedback wiring LRa. A first end of the third voltage divider resistor 86 is connected to the first feedback wiring LRa, and a second end of the third voltage divider resistor 86 is connected to the input-side common wiring Ls and a first end of the fourth voltage divider resistor 87. A second end of the fourth voltage divider resistor 87 is connected to ground. The fifth voltage divider resistor 88 and the sixth voltage divider resistor 89 are provided corresponding to the second feedback wiring LRb. A first end of the fifth voltage divider resistor 88 is connected to the second feedback wiring LRb, and a second end of the fifth voltage divider resistor 88 is connected to the input-side common wiring Ls and a first end of the sixth voltage divider resistor 89. A second end of the sixth voltage divider resistor 89 is connected to ground.

[0092] The seventh voltage divider resistor 90 and the eighth voltage divider resistor 91 are provided corresponding to the third feedback wiring LRc. A first end of the seventh voltage divider resistor 90 is connected to the third feedback wiring LRc, and a second end of the seventh voltage divider resistor 90 is connected to the input-side common wiring Ls and a first end of the eighth voltage divider resistor 91. A second end of the eighth voltage divider resistor 91 is connected to ground. The ninth voltage divider resistor 92 and the tenth voltage divider resistor 93 are provided corresponding to the fourth feedback wiring LRd. A first end of the ninth voltage divider resistor 92 is connected to the fourth feedback wiring LRd, and a second end of the ninth voltage divider resistor 92 is connected to the input-side common wiring Ls and a first end of the tenth voltage divider resistor 93. A second end of the tenth voltage divider resistor 93 is connected to ground. The eleventh voltage divider resistor 94 and the twelfth voltage divider resistor 95 are provided corresponding to the fifth feedback wiring LRe. A first end of the eleventh voltage dividing resistor 94 is connected to the fifth feedback wiring LRe, and a second end of the eleventh voltage dividing resistor 94 is connected to the input-side common wiring Ls and a first end of the twelfth voltage dividing resistor 95. A second end of the twelfth voltage dividing resistor 95 is connected to ground.

[0093] The configuration of the common wiring connecting the feedback wirings LRa-LRe may be changed. For example, as shown in FIG. 6, the isolated power supply 100 may be provided with a first common wiring Ls1 and a second common wiring Ls2. The first common wiring Ls1 corresponds to the input-side common wiring Ls in FIG. 2. The second common wiring Ls2 is connected to the feedback wirings LRa-LRe. Here, the third terminals T3a-T3e of the transformers 60a-60e are connected via the second common wiring Ls2. The anodes of the feedback diodes 71a-71e are connected to the second common wiring Ls2. Note that in FIG. 6, the same components as those shown in FIG. 2 are denoted by the same reference numerals for convenience.

[0094] There is a concern that the length of the path of the first closed circuit, which includes the feedback windings 63a-63e, the feedback wirings LRa-LRe, and the first common wiring Ls1, increases the voltage drop in the first closed circuit, making it difficult for current to flow through the first closed circuit. In this regard, according to this embodiment, the third terminals T3a-T3e of the transformers 60a-60e are connected via the second common wiring Ls2. This forms a second closed circuit, which includes the feedback windings 63a-63e and the second common wiring Ls2. In this case, the path of the second closed circuit is prevented from becoming longer than the path of the first closed circuit. Therefore, magnetic energy stored in the transformers 60a-60e can be exchanged while suppressing an increase in the voltage drop in the closed circuit.

[0095] Instead of connecting the bleeder resistors to the feedback wirings LRa to LRe, the bleeder resistors may be connected to the input common wiring Ls. In this embodiment, as shown in FIG. 7, the isolated power supply 100 includes a common bleeder resistor 74. A first end of the common bleeder resistor 74 is connected to the input common wiring Ls, and a second end of the common bleeder resistor 74 is connected to ground. In FIG. 7, the same components as those shown in FIG. 2 are denoted by the same reference numerals for convenience.

[0096] According to this embodiment, a first end of the common bleeder resistor 74 is connected to the input-side common wiring Ls. In this configuration, a bleeder resistor is not provided corresponding to each of the feedback wirings LRa to LRe, so the number of bleeder resistors can be reduced compared to when a bleeder resistor is connected to each of the feedback wirings LRa to LRe.

[0097] The bleeder resistors do not necessarily have to be provided in correspondence with each of the feedback windings 63a to 63e, but may be provided in correspondence with any one, two, three, or four of the feedback windings 63a to 63e.

[0098] The switches SCH, SCL, SUH to SWL that constitute the inverter 12 and the boost converter 30 are not limited to IGBTs, and may be, for example, N-channel MOSFETs made of Si.

[0099] The lower arm transformer is not limited to a common transformer for each of the lower arm switches SCL, SUL, SVL, and SWL, but may be, for example, a transformer provided individually for each of the lower arm switches SCL, SUL, SVL, and SWL. When individual lower arm transformers are provided, each of the switches SCH, SCL, SUH to SWL may be an N-channel MOSFET made of, for example, a SiC (silicon carbide)-based material or a GaN (gallium nitride)-based material instead of an IGBT.

[0100] In this case, as shown in Fig. 8, the isolated power supply 100 includes seventh to tenth transformers 60g to 60j as lower arm transformers. Note that in Fig. 8, the same components as those shown in Fig. 2 are denoted by the same reference numerals for convenience. Also, in Fig. 8, the switches SCH, SCL, SUH to SWL, etc. are not shown.

[0101] The seventh transformer 60g supplies power to the boost lower arm drive circuit DCL, the eighth transformer 60h supplies power to the U-phase lower arm drive circuit DUL, the ninth transformer 60i supplies power to the V-phase lower arm drive circuit DVL, and the tenth transformer 60j supplies power to the W-phase lower arm drive circuit DWL.

[0102] The seventh transformer 60g includes a seventh input winding 61g, a seventh output winding 62g, and a seventh feedback winding 63g, all of which are magnetically coupled by a common core. The eighth transformer 60h includes an eighth input winding 61h, an eighth output winding 62h, and an eighth feedback winding 63h, all of which are magnetically coupled by a common core. The ninth transformer 60i includes a ninth input winding 61i, a ninth output winding 62i, and a ninth feedback winding 63i, all of which are magnetically coupled by a common core. The tenth transformer 60j includes a tenth input winding 61j, a tenth output winding 62j, and a tenth feedback winding 63j, all of which are magnetically coupled by a common core.

[0103] The seventh to tenth input windings 61g to 61j and the seventh to tenth feedback windings 63g to 63j are provided in the low voltage region, and the seventh to tenth output windings 62g to 62j are provided in the high voltage region.

[0104] The output terminal of the seventh transformer 60g is connected to the boost lower arm drive circuit DCL via a seventh output diode 64g and a seventh output capacitor 65g. The output terminal of the eighth transformer 60h is connected to the U-phase lower arm drive circuit DUL via an eighth output diode 64h and an eighth output capacitor 65h. The output terminal of the ninth transformer 60i is connected to the V-phase lower arm drive circuit DVL via a ninth output diode 64i and a ninth output capacitor 65i. The output terminal of the tenth transformer 60j is connected to the W-phase lower arm drive circuit DWL via a tenth output diode 64j and a tenth output capacitor 65j.

[0105] The seventh transformer 60g has first to fourth terminals T1g to T4g. The first terminal T1g of the seventh transformer 60g is connected to the second terminal T2g of the seventh transformer 60g via a seventh input winding 61g. The third terminal T3g of the seventh transformer 60g is connected to the fourth terminal T4g of the seventh transformer 60g via a seventh feedback winding 63g. When the potential of the first terminal T1g relative to the second terminal T2g of the seventh transformer 60g is higher, an induced voltage is generated in the seventh feedback winding 63g such that the potential of the fourth terminal T4g of the seventh transformer 60g is higher than the potential of the third terminal T3g.

[0106] The eighth transformer 60h has first to fourth terminals T1h to T4h. The first terminal T1h of the eighth transformer 60h is connected to the second terminal T2h of the eighth transformer 60h via an eighth input winding 61h. The third terminal T3h of the eighth transformer 60h is connected to the fourth terminal T4h of the eighth transformer 60h via an eighth feedback winding 63h. When the potential of the first terminal T1h is higher than that of the second terminal T2h of the eighth transformer 60h, an induced voltage is generated in the eighth feedback winding 63h such that the potential of the fourth terminal T4h of the eighth transformer 60h is higher than that of the third terminal T3h.

[0107] The ninth transformer 60i is provided with first to fourth terminals T1i to T4i. The first terminal T1i of the ninth transformer 60i is connected to the second terminal T2i of the ninth transformer 60i via a ninth input winding 61i. The third terminal T3i of the ninth transformer 60i is connected to the fourth terminal T4i of the ninth transformer 60i via a ninth feedback winding 63i. When the potential of the first terminal T1i relative to the second terminal T2i of the ninth transformer 60i is higher, an induced voltage is generated in the ninth feedback winding 63i such that the potential of the fourth terminal T4i of the ninth transformer 60i is higher than the potential of the third terminal T3i.

[0108] The tenth transformer 60j has first to fourth terminals T1j to T4j. The first terminal T1j of the tenth transformer 60j is connected to the second terminal T2j of the tenth transformer 60j via a tenth input winding 61j. The third terminal T3j of the tenth transformer 60j is connected to the fourth terminal T4j of the tenth transformer 60j via a tenth feedback winding 63j. When the potential of the first terminal T1j is higher than that of the second terminal T2j of the tenth transformer 60j, an induced voltage is generated in the tenth feedback winding 63j such that the potential of the fourth terminal T4j of the tenth transformer 60j is higher than that of the third terminal T3j.

[0109] The first terminal T1g of the seventh transformer 60g is connected to the positive terminal of the low-voltage battery 42 via a fifth positive wiring LPe. The second terminal T2g of the seventh transformer 60g is connected to the drain of the control switch 51 via first and fifth negative wirings LNa and LNe. The third terminal T3g of the seventh transformer 60g is connected to the input-side common wiring Ls via a seventh feedback wiring LRg. The fourth terminal T4g of the seventh transformer 60g is connected to ground via a seventh ground wiring LGg.

[0110] The first terminal T1h of the eighth transformer 60h is connected to the fifth positive wiring LPe via the eighth positive wiring LPh. That is, the first terminal T1h of the eighth transformer 60h is connected to the positive terminal of the low-voltage battery 42 via the fifth and eighth positive wirings LPe and LPh. The second terminal T2h of the eighth transformer 60h is connected to the fifth negative wiring LNe via the eighth negative wiring LNh. That is, the second terminal T2h of the eighth transformer 60h is connected to the drain of the control switch 51 via the first, fifth, and eighth negative wirings LNa, LNe, and LNh. The third terminal T3h of the eighth transformer 60h is connected to the input-side common wiring Ls via the eighth feedback wiring LRh. The fourth terminal T4h of the eighth transformer 60h is connected to ground via the eighth ground wiring LGh.

[0111] The first terminal T1i of the ninth transformer 60i is connected to the fifth positive wiring LPe via the ninth positive wiring LPi. That is, the first terminal T1i of the ninth transformer 60i is connected to the positive terminal of the low-voltage battery 42 via the fifth and ninth positive wirings LPe and LPi. The second terminal T2i of the ninth transformer 60i is connected to the fifth negative wiring LNe via the ninth negative wiring LNi. That is, the second terminal T2i of the ninth transformer 60i is connected to the drain of the control switch 51 via the first, fifth, and ninth negative wirings LNa, LNe, and LNi. The third terminal T3i of the ninth transformer 60i is connected to the input-side common wiring Ls via the ninth feedback wiring LRi. The fourth terminal T4i of the ninth transformer 60i is connected to ground via the ninth ground wiring LGi.

[0112] The first terminal T1j of the tenth transformer 60j is connected to the fifth positive wiring LPe via the tenth positive wiring LPj. That is, the first terminal T1j of the tenth transformer 60j is connected to the positive terminal of the low-voltage battery 42 via the fifth and tenth positive wirings LPe and LPj. The second terminal T2j of the tenth transformer 60j is connected to the fifth negative wiring LNe via the tenth negative wiring LNj. That is, the second terminal T2j of the tenth transformer 60j is connected to the drain of the control switch 51 via the first, fifth, and tenth negative wirings LNa, LNe, and LNj. The third terminal T3j of the tenth transformer 60j is connected to the input-side common wiring Ls via the tenth feedback wiring LRj. The fourth terminal T4j of the tenth transformer 60j is connected to ground via the tenth ground wiring LGj.

[0113] A seventh feedback diode 71g is provided on the seventh feedback wiring LRg. The anode of the seventh feedback diode 71g is connected to the third terminal T3g of the seventh transformer 60g, and the cathode of the seventh feedback diode 71g is connected to the input-side common wiring Ls. An eighth feedback diode 71h is provided on the eighth feedback wiring LRh. The anode of the eighth feedback diode 71h is connected to the third terminal T3h of the eighth transformer 60h, and the cathode of the eighth feedback diode 71h is connected to the input-side common wiring Ls. A ninth feedback diode 71i is provided on the ninth feedback wiring LRi. The anode of the ninth feedback diode 71i is connected to the third terminal T3i of the ninth transformer 60i, and the cathode of the ninth feedback diode 71i is connected to the input-side common wiring Ls. A tenth feedback diode 71j is provided on the tenth feedback wiring LRj. The anode of the tenth feedback diode 71j is connected to the third terminal T3j of the tenth transformer 60j, and the cathode of the tenth feedback diode 71j is connected to the input-side common line Ls.

[0114] The isolated power supply 100 includes seventh to tenth feedback capacitors 72g to 72j. The seventh feedback capacitor 72g connects the cathode of the seventh feedback diode 71g to the seventh ground wiring LGg. As with the seventh feedback capacitor 72g, the eighth to tenth feedback capacitors 72h to 72j connect the cathodes of the corresponding eighth to tenth feedback diodes 71h to 71j to the corresponding eighth to tenth ground wirings LGh to LGj.

[0115] The insulated power supply 100 includes seventh to tenth bleeder resistors 73g to 73j. A first end of the seventh bleeder resistor 73g is connected to the seventh feedback wiring LRg, and a second end of the seventh bleeder resistor 73g is connected to ground. As with the seventh bleeder resistor 73g, first ends of the eighth to tenth bleeder resistors 73h to 73j are connected to the corresponding eighth to tenth feedback wirings LRh to LRj, and second ends of the eighth to tenth bleeder resistors 73h to 73j are connected to ground. The first ends of the seventh to tenth bleeder resistors 73g to 73j are connected to the cathodes of the corresponding feedback diodes 71g to 71j.

[0116] When the control switch 51 is turned on, the seventh feedback diode 71g prevents current from flowing through the seventh feedback winding 63g, and magnetic energy is stored in the seventh transformer 60g. As with the seventh feedback winding 63g, the seventh output diode 64g prevents current from flowing through the seventh output winding 62g. As with the seventh transformer 60g, when the control switch 51 is turned on, magnetic energy is stored in the eighth to tenth transformers 60h to 60j.

[0117] On the other hand, when the control switch 51 is turned off, an induced voltage is generated in the seventh feedback winding 63g such that the potential at the third terminal T3g of the seventh transformer 60g is higher than the potential at the fourth terminal T4g. This causes a current to flow through the seventh feedback winding 63g. Similarly to the seventh feedback winding 63g, a current also flows through the seventh output winding 62g, and power is supplied to the boost lower arm driver circuit DCL.

[0118] As in the case of the seventh transformer 60g, when the control switch 51 is turned off, current flows through the eighth to tenth feedback windings 63h to 63j. Current also flows through the eighth to tenth output windings 62h to 62j, and power is supplied to the corresponding phase lower arm drive circuits DUL to DWL.

[0119] Second Embodiment The second embodiment will be described below, focusing on the differences from the first embodiment. In the first embodiment, when the control switch 51 is turned on and off, the voltages generated in the feedback windings 63a to 63e are used. However, this may be changed so that the voltages generated in at least two of the output windings 62a to 62e are used. In this embodiment, the voltages generated in the output windings 62a to 62e are used to control the on / off of the control switch 51. In this embodiment, the output windings 62a to 62e correspond to "control windings."

[0120] The configuration of the isolated power supply 100 will be described below with reference to Fig. 9. In this embodiment, each transformer 60a-60e has a corresponding input winding 61a-61e and output winding 62a-62e, but does not have a feedback winding. Note that in Fig. 9, the same components as those shown in Fig. 2 are denoted by the same reference numerals for convenience. Also, in Fig. 9, the drive circuits DCH, DCL, DUH-DWL, etc. are not shown.

[0121] Here, the configuration of the output side of each transformer 60a-60e will be described in detail. Each transformer 60a-60e is provided with fifth terminals T5a-T5e and sixth terminals T6a-T6e. The fifth terminal T5a of the first transformer 60a is connected to the sixth terminal T6a of the first transformer 60a via a first output winding 62a. The fifth terminal T5b of the second transformer 60b is connected to the sixth terminal T6b of the second transformer 60b via a second output winding 62b. The fifth terminal T5c of the third transformer 60c is connected to the sixth terminal T6c of the third transformer 60c via a third output winding 62c. The fifth terminal T5d of the fourth transformer 60d is connected to the sixth terminal T6d of the fourth transformer 60d via a fourth output winding 62d. A fifth terminal T5e of the fifth transformer 60e is connected to a sixth terminal T6e of the fifth transformer 60e via a fifth output winding 62e.

[0122] The fifth terminal T5a of the first transformer 60a is connected to the output common line Lt and the boost upper arm drive circuit DCH via the first output wiring LOa. The fifth terminal T5b of the second transformer 60b is connected to the output common line Lt and the U-phase upper arm drive circuit DUH via the second output wiring LOb. The fifth terminal T5c of the third transformer 60c is connected to the output common line Lt and the V-phase upper arm drive circuit DVH via the third output wiring LOc. The fifth terminal T5d of the fourth transformer 60d is connected to the output common line Lt and the W-phase upper arm drive circuit DWH via the fourth output wiring LOd. The fifth terminal T5e of the fifth transformer 60e is connected to the output common line Lt and each of the lower arm drive circuits DCL, DUL, DVL, DWL via the fifth output wiring LOe. The sixth terminals T6a to T6e of each of the transformers 60a to 60e are connected to ground. In this embodiment, each of the output wirings LOa to LOe corresponds to a "control wiring."

[0123] A first output diode 64a is provided on the first output wiring LOa. The anode of the first output diode 64a is connected to the fifth terminal T5a of the first transformer 60a, and the cathode of the first output diode 64a is connected to the boost upper arm drive circuit DCH and the output-side common wiring Lt. A second output diode 64b is provided on the second output wiring LOb. The anode of the second output diode 64b is connected to the fifth terminal T5b of the second transformer 60b, and the cathode of the second output diode 64b is connected to the U-phase upper arm drive circuit DUH and the output-side common wiring Lt. A third output diode 64c is provided on the third output wiring LOc. The anode of the third output diode 64c is connected to the fifth terminal T5c of the third transformer 60c, and the cathode of the third output diode 64c is connected to the V-phase upper arm drive circuit DVH and the output-side common wiring Lt. In this embodiment, the output-side common wiring Lt is provided in a high-voltage region.

[0124] A fourth output diode 64d is provided on the fourth output wiring LOd. The anode of the fourth output diode 64d is connected to the fifth terminal T5d of the fourth transformer 60d, and the cathode of the fourth output diode 64d is connected to the W-phase upper arm drive circuit DWH and the output-side common wiring Lt. A fifth output diode 64e is provided on the fifth output wiring LOe. The anode of the fifth output diode 64e is connected to the fifth terminal T5e of the fifth transformer 60e, and the cathode of the fifth output diode 64e is connected to the lower arm drive circuits DCL, DUL, DVL, DWL and the output-side common wiring Lt. In this embodiment, each of the output diodes 64a to 64e corresponds to a "control diode."

[0125] The above-mentioned first to fifth output capacitors 65a to 65e connect the cathodes of the corresponding output diodes 64a to 64e to the ground. In this embodiment, the first to fifth output capacitors 65a to 65e correspond to "control capacitors."

[0126] The isolated power supply 100 includes an isolated transmission unit that transmits the voltage value of the output common wiring Lt to the power supply IC 50 while electrically insulating the output common wiring Lt from the power supply IC 50. In this embodiment, the isolated power supply 100 includes an A / D converter 52 and an isolator 53 as the isolated transmission unit. The A / D converter 52 is provided in a high-voltage region and converts the voltage value of the output common wiring Lt, which is an analog signal, into a digital signal. The converted digital signal is output to the isolator 53. The isolator 53 is provided in both the low-voltage region and the high-voltage region, straddling the boundary between the low-voltage region and the high-voltage region. The isolator 53 is, for example, a digital isolator that transmits signals using a pair of magnetic coils. The isolator 53 transmits the output value of the A / D converter 52 to the power supply IC 50 while electrically insulating the output common wiring Lt from the power supply IC 50. Note that the isolated transmission unit may be a photocoupler instead of the A / D converter 52 and the isolator 53.

[0127] The power supply IC 50 sets the duty ratio of the control switch 51 based on the voltage value of the output-side common wiring Lt transmitted via the A / D converter 52 and the isolator 53. As a result, the voltages generated in the output windings 62a to 62e are used to control the on / off of the control switch 51.

[0128] According to the present embodiment described above in detail, the following effects can be obtained.

[0129] According to this embodiment, a closed circuit is formed including each of the output windings 62a-62e, each of the output wirings LOa-LOa, and the output-side common wiring Lt. In this case, when a current flows through the formed closed circuit, magnetic energy is transmitted between the transformers 60a-60e from a transformer with high magnetic energy to a transformer with low magnetic energy. This makes it possible to suppress variations in the voltages generated in each of the output windings 62a-62e due to variations in the magnitude of the loads of the drive circuits DCH, DCL, DUH-DWL.

[0130] Furthermore, the voltages generated in the output windings 62a to 62e are used to control the on / off of the control switch 51. Therefore, compared to when the duty ratio of the control switch 51 is set based on the voltage generated in any one of the output windings 62a to 62e, the voltages generated in many output windings are used to set the duty ratio of the control switch 51. This reduces the variation in the output voltages of the transformers 60a to 60e, while reducing the number of transformers that are not subject to control among the output windings 62a to 62e. As a result, the controllability of the output voltage of each transformer 60a to 60e can be improved.

[0131] It is conceivable to provide a feedback winding in the low-voltage region and perform on / off control of the control switch 51 based on the voltage generated in the feedback winding. However, in this case, it is necessary to provide an additional feedback winding in at least two of the transformers 60a to 60e.

[0132] In this regard, in the present embodiment, the fifth terminals T5a to T5e of each of the transformers 60a to 60e are connected to the output-side common wiring Lt via the corresponding output wiring LOa to LOe. The voltage value of the output-side common wiring Lt is then transmitted to the power supply IC 50 via the A / D converter 52 and the isolator 53. This eliminates the need to provide a new feedback winding, thereby preventing an increase in the number of components in the isolated power supply 100. At the same time, as described above, this embodiment improves the controllability of the output voltage of each of the transformers 60a to 60e. In other words, it is possible to improve the controllability of the output voltage of each of the transformers 60a to 60e while preventing an increase in the number of components in the isolated power supply 100.

[0133] Output diodes 64a-64e and output capacitors 65a-65e are provided corresponding to the output windings 62a-62e. The current output from the fifth terminals T5a-T5e of the transformers 60a-60e is rectified by the corresponding output diodes 64a-64e, and the corresponding output capacitors 65a-65e are charged. In this case, current flows in a closed circuit including the output windings 62a-62e, the output wirings LOa-LOe, and the output-side common wiring Lt by transferring charge stored in the output capacitors 65a-65e. This transfers magnetic energy stored in the transformers 60a-60e. Therefore, magnetic energy can be transferred appropriately between the transformers 60a-60e while preventing current from flowing through the closed circuit due to the inductance components of the output windings 62a-62e.

[0134] <Modification of the second embodiment> The configuration of the common wiring connecting the output windings 62a-62e may be changed. For example, as shown in FIG. 10, the insulated power supply 100 may be provided with a third common wiring Lt1 and a fourth common wiring Lt2. The third common wiring Lt1 corresponds to the output-side common wiring Lt in FIG. 9. The fourth common wiring Lt2 connects the output wirings LOa-LOe. Here, the fifth terminals T5a-T5e of the transformers 60a-60e are connected via the fourth common wiring Lt2. The anodes of the output diodes 64a-64e are connected to the fourth common wiring Lt2. Note that in FIG. 10, the same components as those shown in FIG. 9 are denoted by the same reference numerals for convenience.

[0135] There is a concern that the length of the third closed circuit, which includes the output windings 62a-62e, the output wirings LOa-LOe, and the third common wiring Lt1, increases the voltage drop in the third closed circuit, making it difficult for current to flow through the third closed circuit. In this regard, according to this embodiment, the fifth terminals T5a-T5e of the transformers 60a-60e are connected via the fourth common wiring Lt2. That is, the first ends of the output windings 62a-62e are connected via the fourth common wiring Lt2. This forms a fourth closed circuit including the output windings 62a-62e and the fourth common wiring Lt2. In this case, the path through which current flows in the fourth closed circuit is prevented from becoming longer than the path through which current flows in the third closed circuit. Therefore, magnetic energy stored in the transformers 60a-60e can be exchanged while suppressing an increase in the voltage drop in the fourth closed circuit.

[0136] Instead of using the voltages generated in the output windings 62a to 62e to control the on / off of the control switch 51, the voltages generated in at least two of the output windings 62a to 62e may be used.

[0137] <Other embodiments> The above-described embodiments may be modified as follows.

[0138] 1 does not need to include the boost converter 30. In this case, the positive bus 13 is connected to the positive terminal of the high-voltage battery 20, instead of being connected to the collector of the upper-arm boost switch SCH and the first end of the smoothing capacitor 31.

[0139] The application of the isolated power supply device 100 is not limited to the inverter 12 and the boost converter 30. For example, the isolated power supply device 100 may be applied to other power conversion circuits, such as a half-bridge circuit or a full-bridge circuit. The output voltages of the transformers 60a to 60f are not limited to the drive circuits DCH, DCL, and DUH to DWL, but may also be supplied to general electrical loads, such as seat heaters, rear window defroster heaters, headlights, windshield wipers, and air conditioner fans.

[0140] The insulated power supply may be installed not only in an electric vehicle but also in a hybrid vehicle equipped with a motor generator and an engine as a main vehicle engine. In this case, the motor control system is not limited to a one-motor control system but may be a two-motor control system. Specifically, the motor control system includes a first motor generator and a first inverter pair, and a second motor generator and a second inverter pair. The first motor generator and the second motor generator are connected to the drive wheels and the engine as a main vehicle engine via a power split mechanism. The first motor generator is connected to the first inverter and functions as a starter that imparts initial rotation to the engine crankshaft and a generator that supplies power to on-board devices. Meanwhile, the second motor generator is connected to the second inverter and functions as a main vehicle engine. The insulated power supply supplies power to a drive circuit for a switch that constitutes the first inverter and a drive circuit for a switch that constitutes the second inverter.

[0141] The insulated power supply apparatus 100 may be installed in, for example, an aircraft or a ship, and is not limited to being installed in a vehicle, an aircraft, a ship, or other moving object.

[0142] The following describes characteristic configurations extracted from the above-described embodiments. [Configuration 1] An insulated power supply device including a plurality of transformers (60a to 60j) each having an input winding (61a to 61j) and a core around which the input winding is wound, Each of the input windings is connected to a DC power supply (42), and the output side of each of the transformers is connected to a power supply target (DCH, DCL, DUH to DWL) corresponding to each of the transformers, At least two of the transformers have control windings (62a to 62e, 63a to 63j) that are magnetically coupled to the input windings via the cores, a control switch (51) that, when turned on, supplies power from the DC power supply to each of the input windings, and, when turned off, stops the supply of power from the DC power supply to each of the input windings; Control wiring (LRa to LRe, LRg to LRj, LOa to LOe) provided corresponding to each of the control windings; common wiring (Ls, Ls1, Ls2, Lt, Lt1, Lt2), a first end of each of the control windings is connected to ground; a second end of each of the control windings is connected to a first end of the corresponding control wiring; a second end of each of the control lines is connected to the common line; The insulated power supply device includes a control unit (50) that turns the control switch on and off based on the voltage value of the common wiring. [Configuration 2] The isolated power supply device according to configuration 1, wherein the input windings, the control windings (63a to 63j), the control switch, the control wirings (LRa to LRe, LRg to LRj), the common wiring (Ls, Ls1, Ls2), and the control unit are provided in the low-voltage region of an electrically isolated high-voltage region and a low-voltage region. [Configuration 3] control capacitors (72a to 72e, 72g to 72j) provided corresponding to the respective control windings; control diodes (71a to 71e, 71g to 71j) provided on the respective control wirings, a first end of each of the control capacitors is connected to the corresponding control wiring, and a second end of each of the control capacitors is connected to the first end of the corresponding control winding; 3. The isolated power supply apparatus of configuration 2, wherein the anode of each control diode is connected to a second end of the corresponding control winding, and the cathode of each control diode is connected to the common wiring and a first end of the corresponding control capacitor. [Configuration 4] a first voltage dividing resistor (84) and a second voltage dividing resistor (85) connected in series with each other; a first end of the first voltage dividing resistor is connected to the common wiring, a second end of the first voltage dividing resistor is connected to a first end of the second voltage dividing resistor, and a second end of the second voltage dividing resistor is connected to the ground; 4. The isolated power supply device according to configuration 3, wherein a connection point between the first voltage dividing resistor and the second voltage dividing resistor is connected to the control unit. [Configuration 5] the common wiring is a first common wiring (Ls1), 5. The isolated power supply device according to configuration 3 or 4, further comprising a second common wiring (Ls2) that connects the first ends of the control wirings. [Configuration 6] a bleeder resistor (73a to 73e, 73g to 73j) provided corresponding to at least one of the control windings; 6. The isolated power supply device according to any one of configurations 2 to 5, wherein a first end of the bleeder resistor is connected to the corresponding control wire, and a second end of the bleeder resistor is connected to the ground. [Configuration 7] a power conversion circuit (12, 30) having a plurality of series-connected upper arm switches (SCH, SUH to SWH) and lower arm switches (SCL, SUL to SWL); A plurality of upper arm drive circuits (DCH, DUH to DWH) that are the power supply target and drive the upper arm switches; The power supply target is applied to a system including a plurality of lower arm drive circuits (DCL, DUL to DWL) that drive the lower arm switches, The transformer is an upper arm transformer (60a to 60d) whose output side is connected to the upper arm drive circuit; a lower arm transformer (60e) whose output side is connected to the lower arm drive circuit, the upper arm transformers are individually provided corresponding to the respective upper arm drive circuits, the lower arm transformer is a transformer common to each of the lower arm drive circuits, The bleeder resistor is an upper-arm bleeder resistor (73a to 73d) provided corresponding to at least one of the control windings of the upper-arm transformer; a lower-arm bleeder resistor (73e) provided corresponding to the control winding of the lower-arm transformer, 7. The isolated power supply device according to configuration 6, wherein the resistance value of the lower arm bleeder resistor is smaller than the resistance value of the upper arm bleeder resistor. [Configuration 8] A bleeder resistor (74) is provided, 6. The isolated power supply device according to claim 2, wherein a first end of the bleeder resistor is connected to the common wiring, and a second end of the bleeder resistor is connected to the ground. [Configuration 9] the input windings, the control switch, and the control unit are provided in the low voltage region of an electrically insulated high voltage region and a low voltage region, An output winding (62a to 62e) is provided on the output side of each of the transformers and is magnetically coupled to the input winding via the core, The output windings and the common wiring (Lt, Lt1, Lt2) are provided in the high-voltage region, output wiring (LOa to LOe) provided in the high voltage region corresponding to each of the output windings; an insulating transmission unit (52, 53) that is provided in the low voltage region and the high voltage region across the boundary between the low voltage region and the high voltage region, and that transmits a voltage value of the common wiring to the control unit while electrically insulating the common wiring from the control unit; a first end of each of the output windings is connected to the ground; a second end of each of the output windings is connected to a first end of the corresponding output wiring; a second end of each of the output wirings is connected to a corresponding one of the power supply targets; The control windings (62a to 62e) are at least two of the output windings, The control wiring (LOa to LOe) is the output wiring corresponding to each of the control windings, 2. The isolated power supply device according to configuration 1, wherein the common wiring connects second ends of the control wirings and outputs the voltage value to the isolated transmission section. [Configuration 10] control capacitors (65a to 65e) provided corresponding to the respective control windings; control diodes (64a to 64e) provided on the respective control wirings, a first end of each of the control capacitors is connected to the corresponding control wiring, and a second end of each of the control capacitors is connected to the first end of the corresponding control winding; 10. The isolated power supply apparatus of configuration 9, wherein the anode of each control diode is connected to a second end of the corresponding control winding, and the cathode of each control diode is connected to the common wiring and a first end of the corresponding control capacitor. [Configuration 11] the common wiring is a first common wiring (Lt1), 11. The isolated power supply according to claim 10, further comprising a second common wiring (Lt2) that connects first ends of the control wirings. [Explanation of symbols]

[0143] 50...power supply IC, 51...control switch, 60a to 60j...first to tenth transformers, 61a to 61j...first to tenth input windings, 62a to 62e...first to fifth output windings, 63a to 63j...first to tenth feedback windings, 100...insulated power supply device, LRa to LRe, LRg to LRj...first to fifth and seventh to tenth feedback wirings, LOa to LOe...first to fifth output wirings, DCH, DCL...boost upper and lower arm drive circuits, DUH to DWL...U, V, W phase upper and lower arm drive circuits.

Claims

1. An insulated power supply device including a plurality of transformers (60a to 60j) each having an input winding (61a to 61j) and a core around which the input winding is wound, Each of the input windings is connected to a DC power supply (42), and the output side of each of the transformers is connected to a power supply target (DCH, DCL, DUH to DWL) corresponding to each of the transformers, At least two of the transformers have control windings (62a to 62e, 63a to 63j) that are magnetically coupled to the input windings via the cores, a control switch (51) that, when turned on, supplies power from the DC power supply to each of the input windings, and, when turned off, stops the supply of power from the DC power supply to each of the input windings; control wiring (LRa to LRe, LRg to LRj, LOa to LOe) provided corresponding to each of the control windings; common wiring (Ls, Ls1, Ls2, Lt, Lt1, Lt2); a first end of each of the control windings is connected to ground; a second end of each of the control windings is connected to a first end of the corresponding control wiring; a second end of each of the control lines is connected to the common line; An insulated power supply device comprising a control unit (50) that turns on and off the control switch based on the voltage value of the common wiring.

2. 2. The isolated power supply device according to claim 1, wherein the input windings, the control windings (63a to 63j), the control switch, the control wirings (LRa to LRe, LRg to LRj), the common wiring (Ls, Ls1, Ls2), and the control unit are provided in the low-voltage region of an electrically isolated high-voltage region and a low-voltage region.

3. control capacitors (72a to 72e, 72g to 72j) provided corresponding to the respective control windings; control diodes (71a to 71e, 71g to 71j) provided on the respective control wirings, a first end of each of the control capacitors is connected to a corresponding one of the control wirings, and a second end of each of the control capacitors is connected to a first end of a corresponding one of the control windings; 3. The isolated power supply according to claim 2, wherein the anode of each of the control diodes is connected to the second end of the corresponding control winding, and the cathode of each of the control diodes is connected to the common wiring and the first end of the corresponding control capacitor.

4. The voltage dividing resistor includes a first voltage dividing resistor (84) and a second voltage dividing resistor (85) connected in series with each other, a first end of the first voltage dividing resistor is connected to the common wiring, a second end of the first voltage dividing resistor is connected to a first end of the second voltage dividing resistor, and a second end of the second voltage dividing resistor is connected to the ground; 4. The insulated power supply device according to claim 3, wherein a connection point between the first voltage dividing resistor and the second voltage dividing resistor is connected to the control unit.

5. The common wiring is a first common wiring (Ls1), 4. The insulated power supply device according to claim 3, further comprising a second common wiring (Ls2) connecting first ends of the control wirings.

6. a bleeder resistor (73a to 73e, 73g to 73j) provided corresponding to at least one of the control windings; The insulated power supply device according to any one of claims 2 to 5, wherein a first end of the bleeder resistor is connected to the corresponding control wiring, and a second end of the bleeder resistor is connected to the ground.

7. a power conversion circuit (12, 30) having a plurality of series-connected upper arm switches (SCH, SUH to SWH) and lower arm switches (SCL, SUL to SWL); a plurality of upper arm drive circuits (DCH, DUH to DWH) that are the power supply targets and drive the upper arm switches; The power supply target is applied to a system including a plurality of lower arm drive circuits (DCL, DUL to DWL) that drive the lower arm switches, The transformer is an upper arm transformer (60a to 60d) whose output side is connected to the upper arm drive circuit; a lower arm transformer (60e) whose output side is connected to the lower arm drive circuit; the upper arm transformers are individually provided corresponding to the respective upper arm drive circuits, the lower arm transformer is a transformer common to each of the lower arm drive circuits, The bleeder resistor is an upper arm bleeder resistor (73a to 73d) provided corresponding to at least one of the control windings of the upper arm transformer; a lower-arm bleeder resistor (73e) provided corresponding to the control winding of the lower-arm transformer, 7. The insulated power supply device according to claim 6, wherein a resistance value of the lower arm bleeder resistor is smaller than a resistance value of the upper arm bleeder resistor.

8. A bleeder resistor (74) is provided, 6. The insulated power supply device according to claim 2, wherein a first end of the bleeder resistor is connected to the common wiring, and a second end of the bleeder resistor is connected to the ground.

9. the input windings, the control switch, and the control unit are provided in the low voltage region of an electrically insulated high voltage region and a low voltage region, An output winding (62a to 62e) is provided on the output side of each transformer, and is magnetically coupled to the input winding via the core. The output windings and the common wiring (Lt, Lt1, Lt2) are provided in the high-voltage region, output wiring (LOa to LOe) provided in the high-voltage region corresponding to each of the output windings; an insulating transmission unit (52, 53) that is provided in the low voltage region and the high voltage region across the boundary between the low voltage region and the high voltage region, and that transmits the voltage value of the common wiring to the control unit while electrically insulating the common wiring from the control unit; a first end of each of the output windings connected to the ground; a second end of each of the output windings is connected to a first end of the corresponding output wiring; a second end of each of the output wirings is connected to a corresponding one of the power supply targets; The control windings (62a to 62e) are at least two of the output windings, The control wiring (LOa to LOe) is the output wiring corresponding to each of the control windings, 2. The insulated power supply device according to claim 1, wherein the common wiring connects second ends of the control wirings and outputs the voltage value to the isolated transmission section.

10. control capacitors (65a to 65e) provided corresponding to the respective control windings; control diodes (64a to 64e) provided on the respective control wirings; a first end of each of the control capacitors is connected to a corresponding one of the control wirings, and a second end of each of the control capacitors is connected to a first end of a corresponding one of the control windings; 10. The isolated power supply according to claim 9, wherein the anode of each of the control diodes is connected to the second end of the corresponding control winding, and the cathode of each of the control diodes is connected to the common wiring and the first end of the corresponding control capacitor.

11. The common wiring is a first common wiring (Lt1), The insulated power supply device according to claim 10, further comprising a second common wiring (Lt2) that connects first ends of the control wirings.

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