Power conversion device

Abstract

To provide a power conversion device with which the charging efficiency of a storage battery can be enhanced in a case where a motor and an inverter are used as chargers for charging the storage battery.SOLUTION: A power conversion device 10 includes: a motor 30 that uses a storage battery 20 as a power source; and an inverter 40 that is connected to the storage battery 20 and controls currents flowing through phase winding wires 31U, 31V, 31W of the motor 30. The power conversion device 10 includes a connection part 70 that, via the phase winding wires 31U, 31V, 31W, connects one end of a single-phase AC power source 60 to upper and lower arm switches of two phases of the three phases of the inverter 40, and connects the other end of the single-phase AC power source 60 to upper and lower arm switches of the remaining one phase. The upper and lower arm switches of the two phases of the three phases are used for current feedback control of the currents flowing through the phase winding wires 31U, 31V, 31W. The upper and lower arm switches of the remaining one phase are used to rectify an output current from the single-phase AC power source 60.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a power conversion device including a motor and an inverter. [Background technology]

[0002] Conventionally, there is known a technique for charging a power storage unit connected to the DC side of an inverter with a single-phase AC power supply. The single-phase AC power supply is electrically connected to the power storage unit via an armature winding of a motor and the inverter. In this case, the motor and the inverter are used as a charger for charging the power storage unit. An example of such a technique is disclosed in Patent Document 1. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2017-11993 A Summary of the Invention [Problem to be solved by the invention]

[0004] When a motor and an inverter are used as a charger, a circuit for charging a power storage unit may be attached to the power conversion device. In this case, there is a concern that the charging efficiency of the power storage unit may decrease due to losses generated in the auxiliary circuit attached to the power conversion device.

[0005] A main object of the present disclosure is to provide a power conversion device capable of increasing the charging efficiency of a power storage unit when a motor and an inverter are used as a charger for charging the power storage unit. [Means for solving the problem]

[0006] The present disclosure relates to a motor having an armature winding; an inverter that electrically connects a power storage unit and the armature winding and controls a current flowing through the armature winding; In a power conversion device comprising: a connection portion that electrically connects one end of a single-phase AC power source and the armature winding; a rectification unit that electrically connects the other end of the single-phase AC power supply to the power storage unit and rectifies an output current of the single-phase AC power supply so that a charging current flows from the single-phase AC power supply to the power storage unit; Equipped with.

[0007] In the present disclosure, one end of the single-phase AC power supply is electrically connected to the armature winding, and the other end of the single-phase AC power supply is connected to a rectifier. In the rectifier, the AC current of the single-phase AC power supply is rectified so that a charging current for the power storage unit flows, and the power storage unit is charged. In this case, switching control of the inverter is performed to control the current flowing through the armature winding, thereby making it possible to convert the output power of the single-phase AC power supply into charging power for the power storage unit. This makes it unnecessary to provide a circuit for converting AC power input from the single-phase AC power supply, separate from the motor and the inverter, in the power conversion device. Therefore, it is possible to suppress the occurrence of losses in the power conversion device when the power storage unit is charged by the single-phase AC power supply. As a result, it is possible to increase the charging efficiency of the power storage unit. [Brief description of the drawings]

[0008] [Figure 1] 1 is an overall configuration diagram of a control system according to a first embodiment. [Diagram 2] FIG. 4 is a diagram showing an example of a control mode of external charging control. [Diagram 3] 4 is a time chart showing an example of a control mode of external charging control. [Figure 4] FIG. 4 is a diagram showing an example of a control mode of external charging control. [Diagram 5] 4 is a time chart showing an example of a control mode of external charging control. [Figure 6] 5 is a diagram for explaining motor torque generated during external charging control. FIG. [Figure 7] 5 is a diagram for explaining motor torque generated during external charging control. FIG. [Figure 8] 4 is a time chart showing an example of external charging control. [Figure 9] 6 is a diagram for explaining suppression of generation of torque of a motor. FIG. [Figure 10] 6 is a diagram for explaining suppression of generation of torque of a motor. FIG. [Figure 11] FIG. 4 is a functional block diagram of external charging control performed by the motor control device. [Figure 12] 4 is a flowchart showing a processing procedure of external charging control. [Figure 13] FIG. 4 is a diagram showing an example of a method for setting a phase current command amplitude. [Figure 14] FIG. 11 is a diagram showing a control example of current feedback control according to the second embodiment. [Figure 15] FIG. 13 is a diagram for explaining in-phase driving. [Figure 16] FIG. 1 is a diagram for explaining interleave driving. [Figure 17] FIG. 4 is a diagram showing the current flowing through each phase winding during external charging control. [Figure 18] FIG. 13 is a diagram showing the effect of reducing losses occurring during external charging control. [Figure 19] FIG. 13 is a diagram showing the effect of reducing motor torque generated during external charging control. [Figure 20] FIG. 11 is an overall configuration diagram of a control system according to a third embodiment. [Figure 21] FIG. 11 is a configuration diagram of a connection portion according to another embodiment. [Figure 22] FIG. 11 is a configuration diagram of a connection portion according to another embodiment. [Figure 23] FIG. 11 is a configuration diagram of a connection portion according to another embodiment. [Figure 24] FIG. 11 is a configuration diagram of a connection portion according to another embodiment. [Diagram 25] FIG. 13 is an overall configuration diagram of a control system according to another embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] First Embodiment Hereinafter, a first embodiment of a power conversion device according to the present disclosure will be described with reference to the drawings. The power conversion device of the present embodiment is mounted on an electrically-driven vehicle such as an electric vehicle or a hybrid vehicle, and constitutes a control system.

[0010] 1, the control system includes a power conversion device 10 and a storage battery 20. The storage battery 20 is a chargeable and dischargeable secondary battery, and has a terminal voltage of, for example, 100 V or more. The storage battery 20 is, for example, a lithium ion storage battery or a nickel metal hydride storage battery.

[0011] The power conversion device 10 includes a motor 30 and an inverter 40. The motor 30 is driven using a storage battery 20 as a power source. The motor 30 is an in-vehicle main engine and has a rotor. The rotor is capable of transmitting power to the drive wheels of the vehicle. In this embodiment, the motor 30 includes three-phase windings 31U, 31V, and 31W as stator windings. The windings 31U, 31V, and 31W are arranged with a 120° electrical angle difference between them. The motor 30 is, for example, a permanent magnet synchronous machine having a permanent magnet as a field pole in the rotor.

[0012] The inverter 40 includes a switching device section 41 and a motor control device 42. The switching device section 41 includes three-phase series-connected elements of U-, V-, and W-phase upper arm switches QUH, QVH, and QWH and U-, V-, and W-phase lower arm switches QUL, QVL, and QWL. The motor control device 42 controls the motor 30 and controls the on / off of each of the switches QUH to QWL.

[0013] In this embodiment, voltage-controlled semiconductor switching elements are used as the switches QUH, QVH, QWH, QUL, QVL, and QWL, and more specifically, N-channel MOSFETs (Metal Oxide Semiconductor Field Effect Transistors) are used. Therefore, the high-potential terminal of each of the switches QUH to QWL is the drain, and the low-potential terminal is the source. Each of the switches QUH, QVH, QWH, QUL, QVL, and QWL has a built-in body diode.

[0014] The drains of the upper arm switches QUH, QVH, and QWH of each phase are connected to the positive terminal of the storage battery 20 by a positive side bus Lp such as a bus bar. The sources of the lower arm switches QUL, QVL, and QWL of each phase are connected to the negative terminal of the storage battery 20 by a negative side bus Ln such as a bus bar.

[0015] In each phase, first ends of windings 31U, 31V, 31W are connected to sources of upper-arm switches QUH, QVH, QWH and drains of lower-arm switches QUL, QVL, QWL via conductive members 32U, 32V, 32W such as bus bars. Second ends of U-, V-, W-phase windings 31U, 31V, 31W can be connected to each other at a neutral point O.

[0016] The inverter 40 includes a smoothing capacitor 43. The smoothing capacitor 43 connects the positive bus Lp and the negative bus Ln. The smoothing capacitor 43 may be built in the inverter 40 or may be provided outside the inverter 40.

[0017] The power conversion device 10 includes a voltage sensor 50, a phase current sensor 51, and an angle sensor 52. The voltage sensor 50 detects the voltage of the smoothing capacitor 43. The phase current sensor 51 detects the current flowing through each of the phase windings 31U, 31V, and 31W. The angle sensor 52 detects the rotation angle (specifically, the electrical angle) of the rotor of the motor 30. The detection values ​​of the sensors 50 to 52 are input to the motor control device 42.

[0018] The control system includes a monitoring unit 21. The monitoring unit 21 detects the voltage, current, SOC, and the like of the storage battery 20.

[0019] The motor control device 42 is configured to be able to communicate with the monitoring unit 21. For example, the motor control device 42 and the monitoring unit 21 are able to exchange information such as the detection values ​​of the sensors 50 to 52 and the SOC of the storage battery 20.

[0020] The motor control device 42 is an electronic control unit mainly composed of a microcomputer 44. The microcomputer 44 includes a CPU (Central Processing Unit). The functions provided by the microcomputer 44 can be provided by software recorded in a physical memory device and a computer that executes the software, by software alone, by hardware alone, or by a combination of these. For example, when each microcomputer 44 is provided by an electronic circuit that is hardware, the functions can be provided by a digital circuit including a large number of logic circuits, or by an analog circuit. For example, each microcomputer 44 executes a program stored in a non-transitory tangible storage medium as a storage unit provided in the microcomputer 44. The program includes, for example, a program for a process shown in FIG. 12, which will be described later. A method corresponding to the program is executed by executing a set of instructions that constitute the program. The storage unit is, for example, a non-volatile memory. The program stored in the storage unit can be updated via a communication network such as the Internet, for example, OTA (Over The Air).

[0021] The motor control device 42 performs switching control of the switches QUH-QWL to feedback control the control amount of the motor 30 to a command value based on the detection values ​​of the sensors 50-52. The control amount is, for example, torque. In each phase, the upper arm switches QUH, QVH, and QWH and the lower arm switches QUL, QVL, and QWL are alternately turned on. As a result, the rotational power of the rotor of the motor 30 is transmitted to the drive wheels, and the vehicle runs.

[0022] Next, a configuration relating to external charging control for charging the storage battery 20 by an external charger provided outside the vehicle will be described.

[0023] The control system includes a single-phase AC power supply 60 and an external control device 61. The single-phase AC power supply 60 and the external control device 61 constitute an external charger capable of charging the storage battery 20. The external charger is, for example, a stationary charger. The single-phase AC power supply 60 is, for example, a system power supply. The external control device 61 is an electronic control device mainly composed of a microcomputer. For example, the external control device 61 controls the output voltage and output current, etc., of the single-phase AC power supply 60. The motor control device 42 and the external control device 61 are capable of exchanging information such as the output voltage and output current of the single-phase AC power supply 60.

[0024] The power conversion device 10 includes a connection unit 70. The connection unit 70 electrically connects each of the phase windings 31U, 31V, 31W to a single-phase AC power supply 60. In this case, the control system is brought into a state in which a current can flow from the single-phase AC power supply 60 to the storage battery 20 via the motor 30 and the inverter 40. As a result, the motor 30 and the inverter 40 are used as part of a charger that charges the storage battery 20.

[0025] In detail, the connection unit 70 has U-, V-, and W-phase connection paths 72U, 72V, and 72W, a UV interphase path 73a, and a VW interphase path 73b. The U-phase connection path 72U electrically connects a second end of the U-phase winding 31U to a first end of the single-phase AC power supply 60. The W-phase connection path 72W electrically connects a second end of the W-phase winding 31W to a second end of the single-phase AC power supply 60. In this case, the connection unit 70 is in an external charging state.

[0026] The UV interphase path 73a electrically connects the U-phase connecting path 72U and the V-phase connecting path 72V. The VW interphase path 73b electrically connects the V-phase connecting path 72V and the W-phase connecting path 72W. In this case, a second end of the V-phase winding 31V is electrically connected to the U-phase winding 31U via the UV interphase path 73a. Also, a second end of the V-phase winding 31V is electrically connected to a second end of the W-phase winding 31W via the VW interphase path 73b. The UV interphase path 73a corresponds to a "first current path", and the VW interphase path 73b corresponds to a "second current path".

[0027] The connection unit 70 has a first changeover switch 71a and a second changeover switch 71b. The first changeover switch 71a is provided in a UV inter-phase path 73a. The second changeover switch 71b is provided in a VW inter-phase path 73b. When turned off, each of the changeover switches 71a and 71b blocks bidirectional current flow, and when turned on, allows bidirectional current flow. For example, each of the changeover switches 71a and 71b is a mechanical relay.

[0028] When driving the motor 30 to rotate, when external charging control is not being performed, or when the single-phase AC power supply 60 is not connected to the vehicle side, the motor control device 42 turns on the change-over switches 71a and 71b to electrically connect the second ends of the phase windings 31U, 31V, and 31W to each other at the neutral point O. This brings the phase windings 31U, 31V, and 31W into a Y-connected state. In this case, the connection unit 70 is in a motor driving state.

[0029] When the connection unit 70 is in an external charging state, the motor control device 42 turns on one of the changeover switches 71a, 71b and turns off the other. As a result, the motor control device 42 switches the current path on the second end side of each of the phase windings 31U, 31V, 31W so that the second end of the V-phase winding 31V is electrically connected to one of the second ends of the U-phase windings 31U, 31W and electrically disconnected from the other second end of the V-phase winding 31V.

[0030] 2 and 3 show the control mode of the external charging control when the first changeover switch 71a is turned on and the second changeover switch 71b is turned off. In FIG. 2, when the output voltage of the single-phase AC power supply 60 is positive, the currents Iu and Iv flowing through the U-phase and V-phase windings 31U and 31V are indicated by dashed lines, and the current Iw flowing through the W-phase winding 31W is indicated by a dashed line. Here, the case where the potential of the first end of the single-phase AC power supply 60 is higher than the potential of the second end is considered to be positive, and the case where the potential of the second end is higher than the first end is considered to be negative. In FIG. 3, in each phase, the direction in which the current flows from the second end to the first end of the windings 31U, 31V, and 31W is positive, and the direction in which the current flows from the first end to the second end of the windings 31U, 31V, and 31W is negative.

[0031] An AC current having the same period as the period T of the output current of the single-phase AC power supply 60 flows through each of the phase currents Iu, Iv, Iw. In each of the windings 31U, 31V, the U- and V-phase currents Iu, Iv flow in the same direction. The W-phase current Iw flows in the opposite direction to the U- and V-phase currents Iu, Iv. The period T of the output current of the single-phase AC power supply 60 is, for example, 50 Hz or 60 Hz.

[0032] The motor control device 42 controls the U-phase currents Iu, Iv by controlling the switching of the U-phase upper and lower arm switches QUH, QUL and the V-phase upper and lower arm switches QVH, QVL. This improves the power factor of the AC current and AC voltage input from the single-phase AC power source 60 and adjusts the charging voltage of the storage battery 20, thereby converting the output power of the single-phase AC power source 60 into charging power for the storage battery 20.

[0033] The motor control device 42 performs switching control of the W-phase upper and lower arm switches QWH, QWL in accordance with the polarity of the output voltage of the single-phase AC power supply 60. Specifically, when the output voltage of the single-phase AC power supply 60 is positive, the motor control device 42 turns off the W-phase upper arm switch QWH and turns on the W-phase lower arm switch QWL. On the other hand, when the output voltage of the single-phase AC power supply 60 is negative, the motor control device 42 turns on the W-phase upper arm switch QWH and turns off the W-phase lower arm switch QWL. As a result, the output current of the single-phase AC power supply 60 is rectified so that a current for charging the storage battery 20 flows.

[0034] 4 and 5 show the control mode of the external charging control when the first changeover switch 71a is turned off and the second changeover switch 71b is turned on. In Fig. 4, when the output voltage of the single-phase AC power supply 60 is positive, the V- and W-phase currents Iv and Iw flowing through the V- and W-phase windings 31V and 31W are indicated by dashed lines, and the U-phase current Iu flowing through the U-phase winding 31U is indicated by a dashed line. In Fig. 5, the symbols of the phase currents Iu, Iv, and Iw are defined in the same way as in Fig. 3.

[0035] In each of the windings 31V, 31W, the V- and W-phase currents Iv, Iw flow in the same direction. The U-phase current Iu flows in the opposite direction to the V- and W-phase currents Iv, Iw.

[0036] 2 and 3. Specifically, the motor control device 42 performs switching control of the V- and W-phase upper and lower arm switches QUH, QVH, QUL, and QVL in order to convert the output power of the single-phase AC power supply 60 into charging power for the storage battery 20. The motor control device 42 also performs switching control of the U-phase upper and lower arm switches QUH and QUL in accordance with the polarity of the output voltage of the single-phase AC power supply 60 in order to rectify the output current of the single-phase AC power supply 60.

[0037] In this embodiment, the V-phase winding 31V corresponds to the "third armature winding." In external charging control when the first changeover switch 71a is turned on and the second changeover switch 71b is turned off, the U-phase winding 31U corresponds to the "first armature winding," the W-phase winding 31V corresponds to the "second armature winding," and the W-phase upper and lower arm switches QWH and QWL correspond to the "rectifier." In external charging control when the first changeover switch 71a is turned off and the second changeover switch 71b is turned on, the W-phase winding 31W corresponds to the "first armature winding," the U-phase winding 31U corresponds to the "second armature winding," and the U-phase upper and lower arm switches QUH and QUL correspond to the "rectifier."

[0038] Incidentally, when a current flows through each of the phase windings 31U, 31V, 31W during external charging control, the motor 30 may generate torque depending on the electrical angle θe of the rotor of the motor 30.

[0039] A specific description will be given with reference to Figs. 6 and 7. For convenience, a description will be given of a case where the U-phase current Iu and the V-phase current Iv flow in the positive direction with the same magnitude, and the W-phase current Iw does not flow. In Figs. 6 and 7, the electrical angle θe of the rotor 32 of the motor 30 is shown as the direction of the N pole of the permanent magnet of the rotor 32 in the three-phase fixed coordinate system. For example, the electrical angle θe of the rotor 32 can be set in the range of 0°≦θe≦360°, with the U-phase axis in the three-phase fixed coordinate system being 0° and the clockwise rotation direction being positive. In the following description, the range of the electrical angle θe is expressed as -30°≦θe≦330° for convenience.

[0040] In FIG. 6, in a three-phase fixed coordinate system, the N pole of the permanent magnet of the rotor 32 faces the direction of -30°, and the total current vector IS of the U-phase current vector Iur and the V-phase current vector Ivr flows in the direction of 60°. That is, the total current vector IS of the U-phase current vector Iur and the V-phase current vector Ivr flows in a direction perpendicular to the N pole of the permanent magnet of the rotor 32. In this case, the total current vector IS of the U-phase current vector Iur and the V-phase current vector Ivr flows in the q-axis direction in a two-phase rotating coordinate system (dq coordinate system). Here, the dq-axis coordinate system is a coordinate system obtained by converting the U-, V-, and W-phase currents Iu, Iv, and Iw in the three-phase fixed coordinate system based on the electrical angle θe of the rotor 32. If the total current vector IS flows in the q-axis direction, there is a concern that the motor 30 will generate torque during external charging control.

[0041] In this regard, it is possible to suppress the generation of torque of the motor 30 during external charging control by making the total current vector IS of the U-phase current vector Iur and the V-phase current vector Ivr flow in the same direction as the N pole of the permanent magnet of the rotor 32. For example, as shown in FIG. 7, in a three-phase fixed coordinate system, when the N pole of the permanent magnet of the rotor 32 faces a 60° direction, the total current vector IS of the U-phase current vector Iur and the V-phase current vector Ivr flows in the direction of 60°. In this case, the total current vector IS of the U- and V-phase current vectors Iur and Ivr flows in the positive d-axis direction in the dq coordinate system, and the q-axis current becomes zero. This suppresses the generation of torque of the motor 30. Note that the generation of torque of the motor 30 during external charging control is also suppressed when the total current vector IS of the U- and V-phase current vectors Iur and Ivr flows in the negative d-axis direction in the dq coordinate system, and the q-axis current becomes zero.

[0042] Therefore, the motor control device 42 performs switching control of the switches QUH to QWL so that the q-axis current becomes zero during external charging control.

[0043] Specifically, in the external charging control (see FIG. 4) when the first changeover switch 71a is turned off and the second changeover switch 71b is turned on, it is assumed that the electrical angle θe of the rotor 32 is stopped at −30°.

[0044] When the electrical angle θe of the rotor 32 is −30°, the motor control device 42 performs switching control of the V- and W-phase upper and lower arm switches QVH, QWH, QVL, and QWL in external charging control so that the total current vector IS of the phase current vectors Iur, Ivr, and Iwr flows in the direction of −30° or 150° in the three-phase fixed coordinate system. In this case, as shown in Fig. 8, the W-phase current Iw is set to 0, and the U-phase current Iu and V-phase current Iv are set to AC currents of opposite phases to each other.

[0045] 9 shows the relationship between the U- and V-phase current vectors Iur, Ivr and the rotor 32 at time t1 in FIG. 8. Time t1 is the timing when the U-phase current vector Iur reaches a positive peak value. In this case, the total current vector IS of the U-phase current vector Iur and the V-phase current vector Ivr flows in the same direction as the N pole of the permanent magnet in the rotor 32 (-30° direction). As a result, in the dq coordinate system, the total current vector IS flows in the positive d-axis direction and the q-axis current is set to zero. Therefore, the generation of torque by the motor 30 during external charging control is suppressed.

[0046] 10 shows the relationship between the U- and V-phase current vectors Iur, Ivr and the rotor 32 at time t2 in FIG. 8. Time t2 is the timing when the U-phase current vector Iur reaches a negative peak value. In this case, the total current vector IS of the U-phase current vector Iur and the V-phase current vector Ivr flows in the same direction (150° direction) as the south pole of the permanent magnet in the rotor 32. As a result, in the dq coordinate system, the total current vector IS flows in the negative d-axis direction, and the q-axis current is set to zero. Therefore, the generation of torque by the motor 30 during external charging control is suppressed.

[0047] In external charging control when the first changeover switch 71a is turned off and the second changeover switch 71b is turned on, even if the electrical angle θe of the rotor 32 is an angle other than −30°, the motor control device 42 can perform switching control of the V- and W-phase upper and lower arm switches QVH, QWH, QVL, and QWL so as to suppress generation of torque of the motor 30. Specifically, the motor control device 42 can perform switching control of the V- and W-phase upper and lower arm switches QVH, QWH, QVL, and QWL so that the q-axis current becomes 0 in accordance with the electrical angle θe that is −30°<θe<30° or 150°≦θe<210°.

[0048] In detail, when the electrical angle θe of the rotor 32 is -30°≦θe<30° or 150°≦θe<210°, if the V-phase current amplitude Iva is expressed by the following equation (eq1) and the W-phase current amplitude Iwa is expressed by the following equation (eq2), the q-axis current becomes 0.

[0049]

number

[0050] When the electrical angle θe of the rotor 32 is -30°≦θe<30° or 150°≦θe<210°, the motor control device 42 controls the switching of the V-phase upper and lower arm switches QVH, QVL so that the V-phase current amplitude Iva becomes the value on the right side of the above equation (eq1) at the current electrical angle θe of the rotor 32. When the electrical angle θe of the rotor 32 is -30°≦θe<30° or 150°≦θe<210°, the motor control device 42 controls the switching of the W-phase upper and lower arm switches QWH, QWL so that the W-phase current amplitude Iwa becomes the value on the right side of the above equation (eq2) at the current electrical angle θe of the rotor 32.

[0051] The motor control device 42 can suppress generation of torque of the motor 30 during external charging control when the first changeover switch 71a is turned on and the second changeover switch 71b is turned off. Specifically, the motor control device 42 can perform switching control of the U- and V-phase upper and lower arm switches QUH, QVH, QUL, and QVL so that the q-axis current becomes zero according to the electrical angle θe that satisfies 30°≦θe≦90° or 210°≦θe≦270°.

[0052] In detail, when the electrical angle θe of the rotor 32 is 30°≦θe≦90° or 210°≦θe≦270°, if the U-phase current amplitude Iua is expressed by the following equation (eq3) and the V-phase current amplitude Iva is expressed by the following equation (eq4), the q-axis current becomes 0.

[0053]

number

[0054] Next, a configuration for the motor control device 42 to perform external charging control will be described with reference to Fig. 11. A specific example will be described here in which the electrical angle θe of the rotor 32 is 30°≦θe≦90° or 210°≦θe≦270°. In this case, the motor control device 42 turns on the first changeover switch 71a and turns off the second changeover switch 71b. The motor control device 42 also performs current feedback control of the U- and V-phase currents Iu and Iv, and performs rectification control to rectify the output current of the single-phase AC power supply 60 in the W phase. First, a configuration for performing rectification control will be described below.

[0055] The motor control device 42 includes a rectification control unit 80. The rectification control unit 80 performs switching control of the W-phase upper and lower arm switches QWH, QWL to rectify the output current of the single-phase AC power supply 60 so that a charging current flows from the single-phase AC power supply 60 to the storage battery 20.

[0056] The rectification control unit 80 has a comparing unit 81 and an inverting unit 82. The comparing unit 81 generates an operation signal for the W-phase lower arm switch QWL in accordance with the polarity of the output voltage VAC of the single-phase AC power supply 60. The operation signal for the W-phase lower arm switch QWL is an ON operation signal or an OFF operation signal. The comparing unit 81 is, for example, a comparator.

[0057] Specifically, the output voltage VAC of the single-phase AC power supply 60 is input to a non-inverting input terminal of the comparing unit 81. The comparing unit 81 can use a value acquired from the external control device 61 as the output voltage VAC of the single-phase AC power supply 60. 0 is input to an inverting input terminal of the comparing unit 81 as a determination value for the polarity of the output voltage VAC. When VAC>0, the comparing unit 81 outputs an ON operation signal for the W-phase lower arm switch QWL. On the other hand, when VAC≦0, the comparing unit 81 outputs an OFF operation signal for the W-phase lower arm switch QWL.

[0058] The inversion unit 82 inverts the logic of an operation signal for the W-phase lower arm switch QWL, thereby generating an operation signal for the W-phase upper arm switch QWH.

[0059] Next, a configuration for performing current feedback control of the U- and V-phase currents Iu and Iv will be described.

[0060] The motor control device 42 includes a setting unit 83 that sets a current command value. Here, an example will be described in which the setting unit 83 performs constant voltage control. In the constant voltage control, the setting unit 83 sets a current command value so that the power supply voltage VDC, which is the voltage of the smoothing capacitor 43, becomes the command voltage VDCref. Here, the setting unit 83 sets a U-phase command current Iu* and a V-phase command current Iv* as the current command values.

[0061] Specifically, the setting unit 83 has a voltage deviation calculation unit 84, a voltage feedback control unit 85, a current amplitude calculation unit 86, a current distribution unit 87, a first sine multiplication unit 88a, and a second sine multiplication unit 88b. A command voltage VDCref and a power supply voltage VDC are input to the voltage deviation calculation unit 84. For example, the voltage deviation calculation unit 84 can use a value acquired from a control device higher than the motor control device 42 as the command voltage VDCref. Furthermore, the voltage deviation calculation unit 84 can use a detection value of the voltage sensor 50 as the power supply voltage VDC. The voltage deviation calculation unit 84 calculates the voltage deviation ΔV by subtracting the power supply voltage VDC from the command voltage VDCref.

[0062] The voltage deviation ΔV calculated by the voltage deviation calculation unit 84 is input to the voltage feedback control unit 85. The voltage feedback control unit 85 calculates an effective value Ie of a command current as a manipulated variable for feedback controlling the voltage deviation ΔV to 0. The feedback control used by the voltage feedback control unit 85 may be, for example, proportional-integral control.

[0063] The effective value Ie of the command current calculated by the voltage feedback control unit 85 is input to the current amplitude calculation unit 86. The current amplitude calculation unit 86 calculates a value by multiplying the effective value Ie by √2 as the amplitude Iat of the command current.

[0064] The current distributor 87 receives the amplitude Iat of the command current calculated by the current amplitude calculator 86 and the electrical angle θe of the rotor 32. The current distributor 87 can use the detection value of the angle sensor 52 as the electrical angle θe of the rotor 32. Based on the amplitude Iat and the electrical angle θe of the command current, the current distributor 87 calculates a U-phase command current amplitude Iua* and a V-phase command current amplitude Iva* so that the q-axis current flowing through each of the phase windings 31U, 31V, 31W becomes zero. The U-phase command current amplitude Iua* is input to a first sine multiplier 88a. The V-phase command current amplitude Iva* is input to a second sine multiplier 88b.

[0065] For example, the current distributor 87 can calculate the U- and V-phase command current amplitudes Iua* and Iva* by setting Ia to the amplitude Iat of the command current and θe to the detection value of the angle sensor 52 in the right-hand sides of the above equations (eq3) and (eq4).

[0066] The sine (sin θe) of the electrical angle θe of the rotor 32 is input to each of the sine multiplication units 88a, 88b. Each of the sine multiplication units 88a, 88b can use a value calculated using the detection value of the angle sensor 52 as the sine of the electrical angle θe of the rotor 32. The first sine multiplication unit 88a calculates a U-phase command current Iu* by multiplying the U-phase command current amplitude Iua* input from the setting unit 83 by the sine of the electrical angle θe, "sin θe". The second sine multiplication unit 88b calculates a V-phase command current Iv* by multiplying the V-phase command current amplitude Iva* input from the setting unit 83 by the sine of the electrical angle θe, "sin θe".

[0067] The motor control device 42 includes a first current deviation calculation unit 89a and a second current deviation calculation unit 89b. The U-phase command current Iu* and the U-phase current Iu calculated by the first sine multiplication unit 88a are input to the first current deviation calculation unit 89a. The V-phase command current Iv* and the V-phase current Iv calculated by the second sine multiplication unit 88b are input to the second current deviation calculation unit 89b. The first and second current deviation calculation units 89a and 89b can use the detection values ​​of the phase current sensor 51 as the U- and V-phase currents Iu and Iv.

[0068] The first current deviation calculation unit 89a calculates a U-phase current deviation ΔIu by subtracting the U-phase current Iu from the U-phase command current Iu*. The second current deviation calculation unit 89b calculates a V-phase current deviation ΔIv by subtracting the V-phase current Iv from the V-phase command current Iv*.

[0069] The motor control device 42 includes a first current feedback control unit 90a and a second current feedback control unit 90b. The U-phase current deviation ΔIu calculated by the first current deviation calculation unit 89a is input to the first current feedback control unit 90a. The first current feedback control unit 90a calculates a U-phase command voltage Vu* as a manipulated variable for feedback controlling the U-phase current deviation ΔIu to zero.

[0070] The second current feedback control unit 90b receives the V-phase current deviation ΔIv calculated by the second current deviation calculation unit 89b. The second current feedback control unit 90b calculates a V-phase command voltage Vv* as a manipulated variable for feedback controlling the V-phase current deviation ΔIv to 0. The feedback control used by each of the current feedback control units 90a and 90b may be, for example, proportional-integral control.

[0071] The motor control device 42 includes a first modulation unit 91a and a second modulation unit 91b. A detection value of the voltage sensor 50 is input to each of the modulation units 91a and 91b as a power supply voltage VDC. The first modulation unit 91a calculates a U-phase modulation factor Mu by dividing a U-phase command voltage Vu* calculated by the first current feedback control unit 90a by the power supply voltage VDC. The second modulation unit 91b calculates a V-phase modulation factor Mv by dividing a V-phase command voltage Vv* calculated by the second current feedback control unit 90b by the power supply voltage VDC.

[0072] The motor control device 42 includes a feedforward control unit 92. The feedforward control unit 92 performs processing to add a feedforward term to each phase modulation factor Mu, Mu.

[0073] Specifically, the feedforward control unit 92 has an absolute value acquisition unit 93, a first feedforward term calculation unit 94, a second feedforward term calculation unit 95, a selection unit 96, a first adder 97a, and a second adder 97b.

[0074] The absolute value acquiring unit 93 acquires the absolute value |VAC| of the output voltage VAC of the single-phase AC power supply 60. The absolute value acquiring unit 93 can use a value acquired from the external control device 61 as the output voltage VAC of the single-phase AC power supply 60.

[0075] The first feedforward term calculation unit 94 receives the absolute value |VAC| of the output voltage VAC in the single-phase AC power supply 60 acquired by the absolute value acquisition unit 93 and the detection value of the voltage sensor 50 as the power supply voltage VDC. The first feedforward term calculation unit 94 calculates the first feedforward term "|VAC| / VDC" by dividing the absolute value |VAC| of the output voltage VAC in the single-phase AC power supply 60 by the power supply voltage VDC.

[0076] The first feedforward term is input to the second feedforward term calculation unit 95. The second feedforward term calculation unit 95 subtracts the first feedforward term from 1 to calculate the second feedforward term “1−|VAC| / VDC”.

[0077] The selection unit 96 receives the first and second feedforward terms and the output voltage VAC of the single-phase AC power supply 60. The selection unit 96 can use a value acquired from the external control device 61 as the output voltage VAC of the single-phase AC power supply 60. If VAC≦0, the selection unit 96 selects the first feedforward term "|VAC| / VDC". On the other hand, if VAC>0, the selection unit 96 selects the second feedforward term "1-|VAC| / VDC". For example, the selection unit 96 is a multiplexer.

[0078] The first and second adders 97a and 97b receive the first or second feedforward term selected by the selector 96. The first adder 97a adds the feedback term selected by the selector 96 to the U-phase modulation factor Mu calculated by the first modulator 91a. The second adder 97b adds the feedback term selected by the selector 96 to the V-phase modulation factor Mv calculated by the second modulator 91b.

[0079] The motor control device 42 includes a first comparison unit 98a and a second comparison unit 98b. The U-phase modulation factor Mu to which the feedforward term has been added is input to the first comparison unit 98a. The first comparison unit 98a generates operation signals for the U-phase upper and lower arm switches QUH, QUL based on a magnitude comparison between the U-phase modulation factor Mu and the carrier signal. The operation signals for the U-phase upper and lower arm switches QUH, QUL are signals that alternately turn on the U-phase upper arm switch QUH and the U-phase lower arm switch QUL.

[0080] The second comparing unit 98b receives the V-phase modulation factor Mv after the feedforward term has been added. The second comparing unit 98b generates operation signals for the V-phase upper and lower arm switches QVH, QVL based on a magnitude comparison between the V-phase modulation factor Mv and the carrier signal. The operation signals for the V-phase upper and lower arm switches QVH, QVL are signals that alternately turn on the V-phase upper arm switch QVH and the V-phase lower arm switch QVL.

[0081] In this embodiment, the first comparison unit 98a and the second comparison unit 98b use signals whose phases are shifted by 180° as carrier signals. The carrier signals are, for example, triangular wave signals. Then, based on the operation signals generated by the comparison units 98a and 98b, the switches QUH, QVH, QUL, and QVL are driven. In this case, the timing at which the U-phase upper arm switch QUH is switched on and the timing at which the V-phase upper arm switch QVH is switched on are shifted by 180° in a switching period. That is, in this embodiment, the U-phase upper and lower arm switches QUH and QUL and the V-phase upper and lower arm switches QVH and QVL are interleaved-driven.

[0082] Note that even when the electrical angle θe of the rotor 32 is −30°≦θe<30° or 150°≦θe<210°, it is possible to perform control similar to the external charging control described with reference to Fig. 11. In this case, the rectification control unit 80, the current distribution unit 87, the sine multiplication units 88a, 88b, the current deviation calculation units 89a, 89b, the current feedback control units 90a, 90b, the addition units 97a, 97b, and the comparison units 98a, 98b function as follows.

[0083] The rectification control unit 80 performs switching control of the U-phase upper and lower arm switches QUH, QUL to rectify the output current of the single-phase AC power supply 60 so that a charging current flows from the single-phase AC power supply 60 to the storage battery 20.

[0084] The current distributor 87 calculates a V-phase command current amplitude Iva* and a W-phase command current amplitude Iwa*. For example, the current distributor 87 can calculate the V-phase and W-phase command current amplitudes Iva* and Iwa* by setting Ia to the amplitude Iat of the command current and θe to the detection value of the angle sensor 52 on the right-hand sides of the above equations (eq1) and (eq2).

[0085] The first sine multiplication unit 88a, the first current deviation calculation unit 89a, the first current feedback control unit 90a, the first addition unit 97a, and the first comparison unit 98a perform current feedback control of the V-phase current Iv. In this case, switching control of the V-phase upper and lower arm switches QVH, QVL is performed based on the operation signal generated by the first comparison unit 98a.

[0086] The second sine multiplication unit 88b, the second current deviation calculation unit 89b, the second current feedback control unit 90b, the second modulation unit 91b, the second addition unit 97b, and the second comparison unit 98b perform current feedback control of the W-phase current Iw. In this case, switching control of the W-phase upper and lower arm switches QWH, QWL is performed based on the operation signal generated by the second comparison unit 98b.

[0087] 12 shows a processing procedure of the external charging control performed by the motor control device 42. The external charging control is performed, for example, by a command from a control device higher than the motor control device 42. Here, it is assumed that a first end of the single-phase AC power supply 60 is electrically connected to the U-phase connecting path 72U and a second end of the single-phase AC power supply 60 is electrically connected to the W-phase connecting path 72W.

[0088] In step S10, the stop position of the rotor 32 of the motor 30 is adjusted. For example, the rotor 32 is rotated so that the electrical angle θe of the rotor 32 is -30°≦θe≦90° or 150°≦θe≦270°. In this case, the first and second changeover switches 71a and 71b are turned on to perform switching control of the switches QUH to QWL. This causes current to flow through the phase windings 31U, 31V, and 31W, causing the rotor 32 to rotate and adjusting the stop position of the rotor 32.

[0089] In step S11, it is determined whether the electrical angle θe of the rotor 32 after adjustment is 30°≦θe≦90° or 210°≦θe≦270°. If the determination in step S11 is affirmative, the process proceeds to step S12. In step S12, the first changeover switch 71a is turned on and the second changeover switch 71b is turned off.

[0090] If the determination in step S11 is negative, it is determined that the electrical angle θe of the rotor 32 after adjustment is -30°≦θe<30° or 150°≦θe<210°, and the process proceeds to step S13. In step S13, the first changeover switch 71a is turned off and the second changeover switch 71b is turned on. The processes in steps S11, S12, and S13 correspond to a "switching control unit."

[0091] In step S14, it is determined whether or not an abnormality has occurred in the control system. For example, if a leakage detection device (not shown) determines that a leakage has occurred between the storage battery 20 and the installation unit, it is determined that an abnormality has occurred in the control system. If the determination in step S14 is affirmative, the process proceeds to step S15, where the external charging control is stopped. On the other hand, if the determination in step S15 is negative, the process proceeds to step S16.

[0092] In step S16, it is determined whether the storage battery 20 is in a fully charged state. Specifically, when the SOC of the storage battery 20 is equal to or greater than a predetermined fully charged determination value, it is determined that the storage battery 20 is in a fully charged state. If the determination in step S16 is affirmative, the process proceeds to step S15. On the other hand, if the determination in step S16 is negative, the process proceeds to step S17.

[0093] In step S17, it is determined whether or not the SOC of the storage battery 20 is smaller than a predetermined value. If a negative determination is made in step S17, the process proceeds to step S18. In step S18, it is determined whether or not the SOC of the storage battery 20 is within a predetermined range. For example, the predetermined range is a range of SOC determined by a predetermined value used in the process of step S17 and an upper limit value that is greater than the predetermined value. Note that in the processes of steps S16, S17, and S18, a value acquired from the monitoring unit 21 can be used as the SOC of the storage battery 20.

[0094] If the determination in step S17 is affirmative, the process proceeds to step S19, where constant current control is performed. If the determination in step S18 is affirmative, the process proceeds to step S20, where constant power control is performed. If the determination in step S18 is negative, the process proceeds to step S21, where constant voltage control is performed.

[0095] The processes of steps S19, S20, and S21 are processes for calculating the effective value Ie of the command current. In step S19, the effective value Ie of the command current is calculated so that the charging current of the storage battery 20 becomes a constant current. In step S20, the effective value Ie of the command current is calculated so that the charging power of the storage battery 20 becomes a constant power. In step S21, the effective value Ie of the command current is calculated so that the charging voltage of the storage battery 20 becomes a constant voltage. In step S21, the motor control device 42 functions as the voltage deviation calculation unit 84 and the voltage feedback control unit 85 described above in FIG. 11.

[0096] In step S22, the amplitude Iat of the command current is set. In this case, the motor control device 42 functions as the current amplitude calculation unit 86 described above with reference to FIG.

[0097] In step S23, it is determined whether or not the first changeover switch 71a is turned on and the second changeover switch 71b is turned off. If the determination in step S23 is affirmative, the process proceeds to step S24. On the other hand, if the determination in step S23 is negative, the process proceeds to step S25.

[0098] In step S24, U- and V-phase command currents Iu* and Iv* are set based on the amplitude Iat of the command current and the electrical angle θe of the rotor 32 so that the q-axis current flowing through each phase winding 31U, 31V, 31W becomes 0. In step S25, V- and W-phase command currents Iv* and Iw* are set based on the amplitude Iat of the command current and the electrical angle θe of the rotor 32 so that the q-axis current flowing through each phase winding 31U, 31V, 31W becomes 0. In steps S24 and S25, the motor control device 42 functions as the current distributor 87 and each sine multiplier 88a, 88b described above in FIG.

[0099] Fig. 13 shows an example of the command current amplitudes Iua*, Iva*, Iwa* of each phase determined corresponding to the electrical angle θe of the rotor 32. The waveforms of the command current amplitudes Iua*, Iva*, Iwa* of each phase in Fig. 13 are obtained by multiplying Ia in the above equations (eq1), (eq2), (eq3), and (eq4) by the command current amplitude Iat. For each phase, the phase command current amplitudes Iua*, Iva*, Iwa* are multiplied by the sine of the electrical angle θe of the rotor 32, "sin θe," and are set as the phase command currents Iu*, Iv*, Iw*.

[0100] In addition, in Figure 13, the phase command current is not determined in region R where 90°<θe<150° and 270°<θe<330°, because in the previous processing of step S10, the electrical angle θe is adjusted to be a value within the range of -30°≦θe≦90° or 150°≦θe≦270°.

[0101] In step S26, current feedback control is performed based on the phase command current set in the process of step S24 or S25. In this case, the motor control device 42 functions as each of the current deviation calculation units 89a, 89b, each of the current feedback control units 90a, 90b, each of the modulation units 91a, 91b, the feedforward control unit 92, and each of the comparison units 98a, 98b. In addition, control is performed to rectify the output current of the single-phase AC power supply 60 so that a charging current flows for the storage battery 20. In this case, the motor control device 42 functions as a rectification control unit 80. The processes of steps S24, S25, and S26 correspond to a "current control unit."

[0102] According to the present embodiment described above in detail, the following effects can be obtained.

[0103] The single-phase AC power supply 60 is electrically connected to the inverter 40 via the windings 31U, 31V, and 31W of each phase. In this case, the upper and lower arm switches for two phases out of the upper and lower arm switches for three phases that the inverter 40 has are switched to control the current flowing through the windings 31U, 31V, and 31W of each phase. This improves the power factor of the AC current and AC voltage input from the single-phase AC power supply 60 and adjusts the charging voltage of the storage battery 20, thereby converting the output power of the single-phase AC power supply 60 into the charging power of the storage battery 20. In other words, the motor 30 and the inverter 40 are used as a conversion circuit that converts the output power of the single-phase AC power supply 60 into the charging power of the storage battery 20. Therefore, it is not necessary to provide a circuit for converting the output power of the single-phase AC power supply 60 into the charging power of the storage battery 20 separately from the motor 30 and the inverter 40. As a result, when the storage battery 20 is charged by the single-phase AC power supply 60, it is possible to suppress the occurrence of loss in the power conversion device 10 and to improve the charging efficiency of the storage battery 20.

[0104] The upper and lower arm switches of the remaining three phases are switched, and the AC current of the single-phase AC power supply 60 is rectified so that a charging current for the storage battery 20 flows. In this case, the inverter 40 is used as a conversion circuit that converts the output power of the single-phase AC power supply 60 into charging power for the storage battery 20, and is also used as a rectifier circuit that rectifies the output current of the single-phase AC power supply 60. This eliminates the need to provide a rectifier circuit that rectifies the output current of the single-phase AC power supply 60 separately from the motor 30 and the inverter 40. Therefore, when the storage battery 20 is charged by the single-phase AC power supply 60, it is possible to appropriately suppress the occurrence of losses in the power conversion device 10, and to appropriately increase the charging efficiency of the storage battery 20.

[0105] The connection unit 70 is configured to electrically connect the second end of the V-phase winding 31V to either one of the second ends of the U-phase windings 31U, 31V and electrically disconnect it from the other. In this case, it is possible to control the current flowing through the phase windings 31U, 31V, 31W so as to prevent the motor 30 from generating torque while the storage battery 20 is being charged. This makes it possible to prevent various inconveniences from occurring due to the torque of the motor 30 being generated while the storage battery 20 is being charged.

[0106] The connection unit 70 is provided with two switches, a first changeover switch 71a and a second changeover switch 71b. In this case, the range of the electrical angle θe of the rotor 32 in which current feedback control can be performed while suppressing torque generation of the motor 30 during charging of the storage battery 20 can be widened compared to a configuration in which only one of the changeover switches 71a and 71b is provided in the connection unit 70. In addition, the number of switches included in the connection unit 70 can be reduced compared to a configuration in which three or more switches are provided on the second end side of each of the phase windings 31U, 31V, and 31W. Therefore, a configuration suitable for charging the storage battery 20 without generating torque of the motor 30 can be realized while reducing the number of switches provided in the connection unit 70.

[0107] In the external charging control, the first changeover switch 71a and the second changeover switch 71b are switched on and off based on the electrical angle θe of the rotor 32 of the motor 30. This makes it possible to set the current electrical angle θe of the rotor 32 within a range in which generation of torque of the motor 30 can be suppressed by current feedback control. Therefore, generation of torque of the motor 30 during charging of the storage battery 20 can be appropriately suppressed.

[0108] The two-phase armature windings are electrically connected via the switch that is turned on out of the first changeover switch 71a and the second changeover switch 71b, and switching control of the upper and lower arm switches provided corresponding to the two-phase armature windings is performed. In this case, switching control of the two-phase upper and lower arm switches is performed based on the current electrical angle θe of the rotor 32 so that the q-axis current flowing through each of the phase windings 31U, 31V, 31W becomes zero. This makes it possible to perform switching control suitable for suppressing the generation of torque by the motor 30 when the storage battery 20 is being charged.

[0109] <Second embodiment> Hereinafter, the second embodiment will be described with reference to the drawings, focusing on the differences from the first embodiment. In this embodiment, the driving method of the switch driven by current feedback control is changed.

[0110] There is a concern that the magnetic flux generated by the current flowing through each phase winding 31U, 31V, 31W during external charging control will leak to the rotor 32 side, increasing iron loss in the motor 30. In this case, there is a concern that the charging efficiency of the storage battery 20 will decrease.

[0111] For example, permanent magnets that do not easily pass magnetic flux are arranged in the d-axis direction of the rotor 32. Meanwhile, iron members such as magnet holders that hold the permanent magnets are arranged in the q-axis direction of the rotor 32. In this case, the q-axis direction of the rotor 32 is a direction in which a magnetic path is more easily formed than the d-axis direction. Therefore, when the total current vector IS of the phase current vectors Iur, Ivr, and Iwr faces the q-axis direction, magnetic flux generated by current flowing through the phase windings 31U, 31V, and 31W is more likely to leak to the rotor 32 side, which may increase iron loss in the motor 30.

[0112] In view of the above, in this embodiment, the motor control device 42 synchronizes the switching controls of the upper and lower arm switches for two phases that are driven by current feedback control.

[0113] Here, a case will be described in which the U-phase upper and lower arm switches QUH, QUL and the V-phase upper and lower arm switches QVH, QVL are driven by current feedback control. The first comparison unit 98a and the second comparison unit 98b use signals with aligned phases as carrier signals. In this case, the timing at which the U-phase upper arm switch QUH is switched on is aligned with the timing at which the V-phase upper arm switch QVH is switched on. This results in in-phase driving in which the switching control of the U-phase upper and lower arm switches QUH, QUL and the switching control of the V-phase upper and lower arm switches QVH, QVL are synchronized.

[0114] 14 and 15 show an example of the phase currents Iu, Iv, Iw when current feedback control is performed. FIG. 14 shows the waveforms of the phase currents Iu, Iv, Iw for one period T of the output current of the single-phase AC power source 60. Here, an example is shown in which the amplitudes of the U-phase current Iu and the V-phase current Iv are controlled to be the same. FIG. 15 shows an enlarged view of the period P in FIG. 14 when the U-phase upper and lower arm switches QUH, QUL and the V-phase upper and lower arm switches QVH, QVL are driven in phase. A ripple current is generated by switching control of the U-phase and V-phase upper and lower arm switches QUH, QVH, QUL, QVL. When driven in phase, the timing of the peak of the ripple current is the same in the U-phase and V-phase.

[0115] Fig. 16 shows an enlarged view of period P in Fig. 14 in the case where the U-phase upper and lower arm switches QUH, QUL and the V-phase upper and lower arm switches QVH, QVL are interleaved. In this case, the timings at which the ripple currents reach their peaks are shifted in the U and V phases.

[0116] FIG. 17 shows a comparison of the phase current vectors Iur, Ivr, Iwr in a three-phase fixed coordinate system in terms of the switch drive method and the frequency components of the phase current vectors Iur, Ivr, Iwr when switching control is performed on the U- and V-phase upper and lower arm switches QUH, QVH, QUL, QVL. As the switch drive method, a comparison is made between a case where the U- and V-phase upper and lower arm switches QUH, QVH, QUL, QVL are interleaved-driven and a case where they are in-phase-driven. As the frequency components of the phase current vectors Iur, Ivr, Iwr, a comparison is made between a fundamental frequency (hereinafter, frequency A) component of the output current of the single-phase AC power supply 60 and a switching frequency (hereinafter, frequency B) component of the U- and V-phase upper and lower arm switches QUH, QVH, QUL, QVL. Frequency B is higher than frequency A. For example, frequency A is 50 Hz and frequency B is 36 kHz.

[0117] The total current vector ISA in the frequency A component of each phase current vector Iur, Ivr, Iwr can be controlled to flow in the same direction as the electrical angle θe (here, 240°) of the rotor 32, regardless of whether each switch QUH, QVH, QUL, QVL is interleaved driven or in-phase driven.

[0118] On the other hand, the total current vector ISB of the frequency B component of each phase current vector Iur, Ivr, Iwr flows in a different direction when the switches QUH, QVH, QUL, QVL are driven in an interleaved manner and when they are driven in phase. In detail, when the switches QUH, QVH, QUL, QVL are driven in an interleaved manner, the total current vector ISB of the frequency B component of each phase current vector Iur, Ivr, Iwr flows in a direction shifted by 90° at an electrical angle θe with respect to the total current vector ISA of the frequency A component of each phase current vector Iur, Ivr, Iwr. Therefore, when the total current vector ISA of the frequency A component of each phase current vector Iur, Ivr, Iwr flows in the same direction as the electrical angle θe, the total current vector ISB of the frequency B component of each phase current vector Iur, Ivr, Iwr flows in the q-axis direction (here, 150°).

[0119] When the switches QUH, QVH, QUL, and QVL are driven in phase, the total current vector ISB in the frequency B component of each phase current vector Iur, Ivr, and Iwr flows in the same direction as the total current vector ISA in the frequency A component of each phase current vector Iur, Ivr, and Iwr. Therefore, when the total current vector ISA in the frequency A component of each phase current vector Iur, Ivr, and Iwr flows in the same direction as the electrical angle θe, the total current vector ISB in the frequency B component of each phase current vector Iur, Ivr, and Iwr flows in the d-axis direction (here, 240°). Therefore, when the switches QUH, QVH, QUL, and QVL are driven in phase, the magnetic flux generated by the current flowing through each phase winding 31U, 31V, and 31W is suppressed from leaking to the rotor 32 side, compared to when the switches are driven in interleaved mode. Therefore, it is possible to suppress an increase in iron loss in the motor 30.

[0120] Fig. 18 shows a comparison of losses occurring during external charging control between the comparative example, the first embodiment, and the second embodiment. In the comparative example, a step-down converter and a rectifier circuit are attached to the power conversion device in addition to the motor and the inverter. In the comparative example, the motor and the inverter are operated as a step-up converter.

[0121] The results of the first embodiment are obtained when the upper and lower arm switches for two phases are interleaved driven in current feedback control. The results of the second embodiment are obtained when the upper and lower arm switches for two phases are in-phase driven in current feedback control.

[0122] In the comparative example, a step-down converter and a rectifier circuit are attached to the power conversion device, which causes loss in the attached circuits. In the first and second embodiments, a circuit for charging the storage battery 20 is not attached to the power conversion device 10 apart from the motor 30 and the inverter 40, so that the occurrence of extra loss is suppressed.

[0123] In the comparative example, when the motor and the inverter are operated as a boost converter, a direct current is input from the neutral point side of each phase winding, and a current flows to the inverter side through each phase winding. In this case, the inductance of the current flow path from the neutral point of each phase winding to the inverter becomes small, and the ripple current may increase. On the other hand, in the first and second embodiments, during external charging control, a current flows through a series connection of any two phase windings of each phase winding 31U, 31V, 31W and the remaining one phase winding. In this case, the inductance of the current flow path during external charging control becomes large, and the increase in the ripple current may be suppressed. Therefore, in the example shown in FIG. 18, the motor loss in the first and second embodiments is reduced compared to the comparative example.

[0124] In the second embodiment, the upper and lower arm switches for two phases driven by current feedback control are driven in phase. In this case, as described above, the magnetic flux generated by the current flowing through the windings 31U, 31V, and 31W of each phase is prevented from leaking to the rotor 32 side. This prevents the occurrence of iron loss in the rotor 32. Therefore, in the second embodiment, the motor loss is further reduced compared to the first embodiment.

[0125] In the first and second embodiments, the loss occurring during external charging control is reduced, thereby improving the charging efficiency, which is the ratio of the power stored in the storage battery 20 to the output power of the single-phase AC power supply 60. In the example shown in Fig. 18, the first embodiment improves the charging efficiency by 6% compared to the comparative example. The second embodiment improves the charging efficiency by 10% compared to the comparative example.

[0126] Fig. 19 shows an example of external charging control in the comparative example, the first embodiment, and the second embodiment. In Fig. 19, (a) shows the waveform of the output voltage VAC of the single-phase AC power supply 60, (b) shows the waveform of the output current IAC of the single-phase AC power supply 60, (c) shows the waveforms of the phase currents Iu, Iv, and Iw, (d) shows the waveform of the voltage of the smoothing capacitor 43, and (e) shows the waveform of the torque Trq generated by the motor 30.

[0127] In the first and second embodiments, the magnitude of the torque Trq generated by the motor 30 is suppressed to a predetermined torque threshold Trqth or less. For example, the torque threshold Trqth is a torque at which the drive wheels configured to be capable of transmitting power to the rotor 32 start to rotate, and is set to the upper limit of the range assumed for the torque at which the drive wheels start to rotate.

[0128] In the second embodiment, the upper and lower arm switches for two phases driven by current feedback control are driven in phase, so that the total current vector ISB in the frequency B component of each phase current vector Iur, Ivr, Iwr is prevented from flowing in the q-axis direction, compared to the first embodiment. Therefore, in the second embodiment, the fluctuation range of the generated torque Trq of the motor 30 is reduced, compared to the first embodiment.

[0129] However, in current feedback control, if the upper and lower arm switches for two phases are driven in phase, there is a concern that the ripple current flowing through each phase winding 31U, 31V, 31W will be larger than when they are driven in an interleaved manner.

[0130] In this regard, in this embodiment, a motor having a standard value of output larger than the time average value of the output power of the single-phase AC power supply 60 is used as the motor 30. For example, the standard value is a value determined according to the specifications of the motor 30, such as the rated output of the motor 30 and the upper limit of the power that the motor 30 can output. For example, the time average value of the output power of the single-phase AC power supply 60 is the product of the effective value of the rated current of the single-phase AC power supply 60 and the effective value of the rated voltage of the single-phase AC power supply 60.

[0131] According to this embodiment, it is possible to suppress the occurrence of problems caused by an increase in ripple current in each of the phase windings 31U, 31V, and 31W, and therefore it is possible to realize a configuration suitable for driving the upper and lower arm switches for two phases in the same phase in current feedback control.

[0132] <Third embodiment> Hereinafter, the third embodiment will be described with reference to the drawings, focusing on the differences from the first embodiment. In this embodiment, as shown in Fig. 20, a rectifier 11 that rectifies the output current of a single-phase AC power supply 60 is provided in addition to an inverter 40.

[0133] The rectifier unit 11 includes an upper arm rectifier switch SH and a lower arm rectifier switch SL. In this embodiment, voltage-controlled semiconductor switching elements, specifically N-channel MOSFETs, are used as the upper arm rectifier switch SH and the lower arm rectifier switch SL. Each of the rectifier switches SH and SL includes a built-in body diode.

[0134] The drain of the upper arm rectifier switch SH and the positive terminal of the storage battery 20 are connected by a positive bus Lp. The source of the lower arm rectifier switch SL and the negative terminal of the storage battery 20 are connected by a negative bus Ln.

[0135] The connection unit 70 has a first connection path 73, a second connection path 74, and a connection switch 75. The first connection path 73 electrically connects a first end of the single-phase AC power supply 60 to a neutral point O of each of the phase windings 31U, 31V, 31W. The second connection path 74 electrically connects a second end of the single-phase AC power supply 60 to a connection point of the upper arm rectifier switch SH and the lower arm rectifier switch SL.

[0136] The connection switch 75 is provided in the first connection path 73. When the connection switch 75 is turned off, it blocks the flow of current in both directions, and when it is turned on, it allows the flow of current in both directions. For example, the connection switch 75 is a mechanical relay.

[0137] When driving the motor 30 to rotate, when external charging control is not being performed, or when the single-phase AC power supply 60 is not connected to the vehicle side, the motor control device 42 turns off the connection switch 75. On the other hand, when external charging control is being performed, the motor control device 42 turns on the connection switch 75.

[0138] In external charging control, the motor control device 42 performs switching control of the upper and lower arm rectifier switches SH, SL in accordance with the polarity of the output voltage of the single-phase AC power supply 60. Specifically, when the output voltage of the single-phase AC power supply 60 is positive, the motor control device 42 turns off the upper arm rectifier switch SH and turns on the lower arm rectifier switch SL. On the other hand, when the output voltage of the single-phase AC power supply 60 is negative, the motor control device 42 turns on the upper arm rectifier switch SH and turns off the lower arm rectifier switch SL.

[0139] In external charging control, the motor control device 42 performs switching control of the upper and lower arm switches QUH, QVH, QWH, QUL, QVL, and QWL of each phase to adjust the charging voltage of the storage battery 20 while improving the power factor of the AC current and AC voltage input from the single-phase AC power source 60.

[0140] For example, during external charging control, the motor control device 42 performs switching control of the switches QUH-QWL so that the magnitude of the current flowing through each of the phase windings 31U, 31V, 31W is equal. In this case, generation of torque of the motor 30 during external charging control is suppressed. Note that the motor control device 42 may perform switching control of the switches QUH-QWL so that the magnitude of the current flowing through each of the phase windings 31U, 31V, 31W is different within a range in which the torque of the motor 30 is equal to or less than a predetermined value.

[0141] According to the present embodiment, the current flowing through each of the phase windings 31U, 31V, 31W is controlled by controlling the switching of each of the switches QUH to QWL of the inverter 40. This converts the output power of the single-phase AC power supply 60 into charging power for the storage battery 20. This makes it possible to avoid providing a circuit for converting the output power of the single-phase AC power supply 60 into charging power, separate from the motor 30 and the inverter 40.

[0142] Furthermore, by controlling the switching of the rectifier switches SH, SL, the AC current of the single-phase AC power supply 60 is rectified so as to flow a charging current for the storage battery 20. In this case, the single-phase AC power supply 60 and the rectifier unit 11 are electrically connected without passing through the phase windings 31U, 31V, 31W. This makes it possible to reduce noise generated by the switching control of the rectifier switches SH, SL, compared to the case where any one of the upper and lower arm switches for three phases is used as a rectifier element.

[0143] <Other embodiments> Each of the above embodiments may be modified as follows.

[0144] The configuration of the connection unit 70 may be changed as shown in Fig. 21. Here, a configuration in which a second changeover switch 71b is not provided in a VW inter-phase path 73b is shown. In Fig. 21, the same components as those shown in Fig. 1 are denoted by the same reference numerals for convenience.

[0145] The connection unit 70 has a VW-phase connection path 76 and a VW-phase connection switch 77. As in the first embodiment, a first end of the single-phase AC power supply 60 is electrically connected to a second end of the U-phase winding 31U via a U-phase connection path 72U. The VW-phase connection path 76 electrically connects a second end of the single-phase AC power supply 60 to a VW inter-phase path 73b. That is, the second end of the single-phase AC power supply 60 is electrically connected to a second end of the W-phase winding 31W via the VW-phase connection path 76, the VW inter-phase path 73b, and the W-phase connection path 72W. Also, the second end of the single-phase AC power supply 60 is electrically connected to a second end of the V-phase winding 31V via the VW-phase connection path 76, the VW inter-phase path 73b, and the V-phase connection path 72V.

[0146] The VW phase connection switch 77 is provided in the VW phase connection path 76. The VW phase connection switch 77 blocks bidirectional current flow when turned off, and allows bidirectional current flow when turned on. For example, the VW phase connection switch 77 is a mechanical relay.

[0147] When driving the motor 30 to rotate, when external charging control is not being performed, or when the single-phase AC power supply 60 is not connected to the vehicle side, the motor control device 42 turns on the first changeover switch 71a and turns off the VW phase connection switch 77.

[0148] On the other hand, when performing external charging control, the motor control device 42 turns off the first changeover switch 71a and turns on the VW-phase connection switch 77. This switches the current path of the connection unit 70 so that the second end of the V-phase winding 31V is electrically connected to the second end of the W-phase winding 31W and electrically disconnected from the second end of the U-phase winding 31U. Note that in this embodiment, the W-phase winding 31W corresponds to the "first armature winding", the U-phase winding 31U corresponds to the "second armature winding", and the V-phase winding 31V corresponds to the "third armature winding".

[0149] In this embodiment, when the electrical angle θe of the rotor 32 is -30°≦θe≦30° or 150°≦θe≦210°, it is possible to control the current flowing through the phase windings 31U, 31V, 31W so as to suppress the generation of torque of the motor 30 during external charging control. In this case, the motor control device 42 executes the external charging control process described above with reference to FIG. 12 with the following modifications.

[0150] In step S10, the rotor 32 is rotated so that the electrical angle θe of the rotor 32 is within the range of -30°≦θe≦30° or 150°≦θe≦210°. In this case, the first changeover switch 71a is turned on and the switches QUH to QWL are switched on and controlled. This causes current to flow through the phase windings 31U, 31V, and 31W, causing the rotor 32 to rotate and adjusting the stop position of the rotor 32. After the process of step S10, the process proceeds to step S12 without performing the process of step S11.

[0151] In step S12, the first changeover switch 71a is turned off, and the VW phase connection switch 77 is turned on.

[0152] After the process of step S22, the process proceeds to step S24 without performing the process of step S23. The process of step S24 is the same as that of the first embodiment. Note that in this embodiment, the processes of steps S13 and S25 are not performed.

[0153] The configuration of the connection unit 70 may be changed as shown in Fig. 22. Here, an example of a configuration is shown in which the range of electrical angle θe at which current can flow through each phase winding 31U, 31V, 31W is -30°≦θe≦330° so that torque generation of the motor 30 is suppressed during external charging control. Note that in Fig. 22, the same reference numerals are used for the same components as those shown in Figs. 1 and 21 above for convenience.

[0154] The connection unit 70 has a third changeover switch 71c, a UW inter-phase path 73c, and a VW phase changeover switch 78. A first end of the single-phase AC power supply 60 is electrically connected to a second end of the U-phase winding 31U via a U-phase connection path 72U, as in the first embodiment. The VW phase changeover switch 78 has three terminals. A first terminal of the VW phase changeover switch 78 is electrically connected to a second end of the single-phase AC power supply 60, a second terminal is electrically connected to the V-phase connection path 72V, and a third terminal is electrically connected to the W-phase connection path 72W. The VW phase changeover switch 78 electrically connects the first terminal to the second terminal or the third terminal. The VW phase changeover switch 78 is, for example, a double-throw switch.

[0155] The UW inter-phase path 73c electrically connects the U-phase connecting path 72U and the W-phase connecting path 72W. The third changeover switch 71c is provided in the UW inter-phase path 73c. ​​When the third changeover switch 71c is turned off, it blocks the flow of bidirectional current, and when the third changeover switch 71c is turned on, it allows the flow of bidirectional current. For example, the third changeover switch 71c is a mechanical relay.

[0156] When driving the motor 30 to rotate, when external charging control is not being performed, or when the single-phase AC power supply 60 is not connected to the vehicle side, the motor control device 42 turns on at least two of the first changeover switch 71a, the second changeover switch 71b, and the third changeover switch 71c. On the other hand, when performing external charging control, the motor control device 42 controls the first changeover switch 71a, the second changeover switch 71b, the third changeover switch 71c, and the VW-phase changeover switch 78 based on the electrical angle θe of the rotor 32.

[0157] Specifically, when the electrical angle θe of the rotor 32 is within a first range, the motor control device 42 turns on the first changeover switch 71a, turns off the second changeover switch 71b and the third changeover switch 71c, and electrically connects the first terminal of the VW-phase changeover switch 78 to the third terminal. Here, the first range is 30°≦θe<90° and 210°≦θe<270°. As a result, the current path of the connection unit 70 is switched so that the second end of the V-phase winding 31V is electrically connected to the second end of the U-phase winding 31U and electrically disconnected from the second end of the W-phase winding 31W. In this case, the U-phase winding 31U corresponds to the "first armature winding", the W-phase winding 31W corresponds to the "second armature winding", and the V-phase winding 31V corresponds to the "third armature winding".

[0158] When the electrical angle θe of the rotor 32 is within a second range, the motor control device 42 turns on the second changeover switch 71b, turns off the first changeover switch 71a and the third changeover switch 71c, and electrically connects the first terminal of the VW-phase changeover switch 78 to the second terminal. Here, the second range is -30°≦θe<30° and 150°≦θe<210°. As a result, the current path of the connection unit 70 is switched so that the second end of the W-phase winding 31W is electrically connected to the second end of the V-phase winding 31V and electrically disconnected from the second end of the U-phase winding 31U. In this case, the V-phase winding 31V corresponds to the "first armature winding", the U-phase winding 31U corresponds to the "second armature winding", and the W-phase winding 31W corresponds to the "third armature winding".

[0159] When the electrical angle θe of the rotor 32 is within a third range, the motor control device 42 turns on the third changeover switch 71c, turns off the first changeover switch 71a and the second changeover switch 71b, and electrically connects the first terminal of the VW-phase changeover switch 78 to the second terminal. Here, the third range is 90°≦θe<150° and 270°≦θe≦330°. As a result, the current path of the connection unit 70 is switched so that the second end of the W-phase winding 31W is electrically connected to the second end of the U-phase winding 31U and electrically disconnected from the second end of the V-phase winding 31V. In this case, the U-phase winding 31U corresponds to the "first armature winding", the V-phase winding 31V corresponds to the "second armature winding", and the W-phase winding 31W corresponds to the "third armature winding".

[0160] In this embodiment, as described above, the changeover switches 71a-71c, 78 are controlled based on the electrical angle θe of the rotor 32, thereby switching the current path of the connection unit 70. This makes it possible to control the current flowing through the phase windings 31U, 31V, 31W so as to suppress the generation of torque of the motor 30 during external charging control. In this case, the motor control device 42 executes the external charging control process described above with reference to FIG. 12 with the following modifications.

[0161] Instead of the processes of steps S10 to S13, a switching process is performed to control the changeover switches 71a to 71c, 78. In the switching process, the changeover switches 71a to 71c, 78 are controlled as described above depending on whether the current electrical angle θe of the rotor 32 is in the first range, the second range, or the third range. Therefore, in this embodiment, it is not necessary to perform the process of adjusting the stop position of the rotor 32 in step S10.

[0162] Instead of the processing of steps S23 to S25, a setting process is performed to set a phase command current so that the q-axis current flowing through each of the phase windings 31U, 31V, 31W becomes 0. In the setting process, the phase for which the phase command current is set is changed depending on whether the current electrical angle θe of the rotor 32 is in the first range, the second range, or the third range.

[0163] Specifically, when the current electrical angle θe of the rotor 32 is within a first range, U- and V-phase command currents Iu* and Iv* are set. When the current electrical angle θe of the rotor 32 is within a second range, V- and W-phase command currents Iv* and Iw* are set. When the current electrical angle θe of the rotor 32 is within a third range, U- and W-phase command currents Iu* and Iw* are set.

[0164] In step S26, current feedback control is performed based on the phase command current set in the setting process. Also, by using upper and lower arm switches in the three phases other than the phase for which current feedback control is performed, control is performed to rectify the output current of the single-phase AC power supply 60 so that a charging current flows from the single-phase AC power supply 60 to the storage battery 20.

[0165] As shown in Fig. 23, the configuration of the connection unit 70 may be changed. Here, a modified configuration in which the process of step S10 does not need to be performed as described above in Fig. 22 is shown. Note that in Fig. 22, the same components as those shown in Fig. 1 are denoted by the same reference numerals for convenience.

[0166] The connection unit 70 has a first power supply path 100, U-, V-, and W-phase first paths 101U, 101V, and 101W, and U-, V-, and W-phase first switches 102U, 102V, and 102W. The first power supply path 100 electrically connects a first end of the single-phase AC power supply 60 to a second end of the U-phase winding 31U via a U-phase first path 101U. A U-phase first switch 102U is provided in the U-phase first path 101U.

[0167] V-phase first path 101V electrically connects a second end of V-phase winding 31V to a portion of U-phase first path 101U that is closer to single-phase AC power supply 60 than U-phase first switch 102U. In other words, the second end of V-phase winding 31V is electrically connected to a first end of single-phase AC power supply 60 via U- and V-phase first paths 101U and 101V and first power supply path 100. V-phase first path 101V is provided with a V-phase first switch 102V.

[0168] The W-phase first path 101W electrically connects a second end of the W-phase winding 31W to a portion of the V-phase first path 101V that is closer to the single-phase AC power supply 60 than the V-phase first switch 102V. In other words, the second end of the W-phase winding 31W is electrically connected to a first end of the single-phase AC power supply 60 via the U-, V-, and W-phase first paths 101U, 101V, and 101W and the first power supply path 100. The W-phase first path 101W is provided with a W-phase first switch 102W.

[0169] In this embodiment, the U-phase interphase path 73a electrically connects a portion of the U-phase first path 101U closer to the U-phase winding 31U than the U-phase first switch 102U and a portion of the V-phase first path 101V closer to the V-phase winding 31V than the V-phase first switch 102V. The V-phase interphase path 73b electrically connects a portion of the V-phase first path 101V closer to the V-phase winding 31V than the V-phase first switch 102V and a portion of the W-phase first path 101W closer to the W-phase winding 31W than the W-phase first switch 102W.

[0170] The connection unit 70 has a second power supply path 103, U-, V-, and W-phase second paths 104U, 104V, and 104W, and U-, V-, and W-phase second switches 105U, 105V, and 105W. The second power supply path 103 electrically connects a second end of the single-phase AC power supply 60 to first ends of the U-, V-, and W-phase second paths 104U, 104V, and 104W.

[0171] A second end of the U-phase second path 104U is electrically connected to a portion of the UV inter-phase path 73a that is closer to the U-phase first path 101U than the first changeover switch 71a. The U-phase second path 104U is provided with a U-phase second switch 105U.

[0172] A second end of a V-phase second path 104V is electrically connected to a portion of the VW inter-phase path 73b that is closer to the V-phase first path 101V than the second changeover switch 71b. A V-phase second switch 105V is provided in the V-phase second path 104V.

[0173] A second end of the W-phase second path 104W is electrically connected to a portion of the W-phase first path 101W that is closer to the W-phase winding 31W than the W-phase first switch 102W. The W-phase second path 104W is provided with a W-phase second switch 105W.

[0174] When driving the motor 30 to rotate, when external charging control is not being performed or when the single-phase AC power supply 60 is not connected to the vehicle side, the motor control device 42 turns on the first and second changeover switches 71a and 71b and turns off the first and second switches 102U, 102V, 102W, 105U, 105V, and 105W of each phase. On the other hand, when performing external charging control, the motor control device 42 controls the switches 71a, 71b, 102U, 102V, 102W, 105U, 105V, and 105W based on the electrical angle θe of the rotor 32.

[0175] For example, based on the electrical angle θe of the rotor 32, the motor control device 42 switches the switches 71a, 71b, 102U, 102V, 102W, 105U, 105V, and 105W as follows.

[0176] When the electrical angle θe of the rotor 32 is within a first range, the motor control device 42 turns on the first changeover switch 71a, the U-phase first switch 102U, and the W-phase second switch 105W, and turns off the second changeover switch 71b, the V- and W-phase first switches 102V and 102W, and the U- and V-phase second switches 105U and 105V. This switches the current path of the connection unit 70 so that the second end of the V-phase winding 31V is electrically connected to the second end of the U-phase winding 31U and electrically disconnected from the second end of the W-phase winding 31W.

[0177] When the electrical angle θe of the rotor 32 is within the second range, the motor control device 42 turns on the second changeover switch 71b, the V-phase first switch 102V, and the U-phase second switch 105U, and turns off the first changeover switch 71a, the U-phase first switches 102U and 102W, and the V-phase second switches 105V and 105W. This switches the current path of the connection unit 70 so that the second end of the W-phase winding 31W is electrically connected to the second end of the V-phase winding 31V and electrically disconnected from the second end of the U-phase winding 31U.

[0178] When the electrical angle θe of the rotor 32 is within the third range, the motor control device 42 turns on the U- and W-phase first switches 102U and 102W and the V-phase second switch 105V, and turns off the first and second changeover switches 71a and 71b, the V-phase first switch 102V, and the U- and W-phase second switches 105U and 105W. This switches the current path of the connection unit 70 so that the second end of the W-phase winding 31W is electrically connected to the second end of the U-phase winding 31U and electrically disconnected from the second end of the V-phase winding 31V.

[0179] Each switch of the connection unit 70 shown in Figs. 1, 20 to 23 may be a semiconductor switching element instead of a mechanical relay. Fig. 24 shows an example in which the first changeover switch 71a and the second changeover switch 71b are configured by a pair of N-channel MOSFETs. In Fig. 24, the drains of the switches constituting the first and second changeover switches 71a and 71b are connected to each other. The first and second changeover switches 71a and 71b may be configured by connecting the sources of the switches to each other.

[0180] 25, the power conversion device 10 may include a DCDC converter 120. In this embodiment, the DCDC converter 120 is an insulating type DCDC converter. The DCDC converter 120 transfers power between the storage battery 20 and the inverter 40 while electrically insulating the storage battery 20 and the inverter 40.

[0181] The DCDC converter 120 is of a DAB (Dual Active Bridge) type and includes a first full bridge circuit 121, a second full bridge circuit 123, and a transformer 122 that transmits power between the full bridge circuits 121 and 123. The transformer 122 includes a first coil 122A connected to the first full bridge circuit 121, a second coil 122B connected to the second full bridge circuit 123, and a core 122C that magnetically couples the coils 122A and 122B. A capacitor and an inductor, which are passive elements, are provided in an electrical path that electrically connects the first coil 122A to the first full bridge circuit 121 and an electrical path that electrically connects the second coil 122B to the second full bridge circuit 123. The DCDC converter 120 may be of another type (for example, an LLC type).

[0182] The power conversion device 10 includes a positive system main relay 130p and a negative system main relay 130n. The positive system main relay 130p is provided in a portion of the positive bus Lp between the storage battery 20 and the inverter 40. The negative system main relay 130n is provided in a portion of the negative bus Ln between the storage battery 20 and the inverter 40. For example, each of the system main relays 130p, 130n is a mechanical relay.

[0183] The first full bridge circuit 121 is connected to the positive bus Lp on the inverter 40 side relative to the positive system main relay 130p and to the negative bus Ln on the inverter 40 side relative to the negative system main relay 130n. The second full bridge circuit 123 is connected to the positive bus Lp on the storage battery 20 side relative to the positive system main relay 130p and to the negative bus Ln on the storage battery 20 side relative to the negative system main relay 130n.

[0184] Each full bridge circuit 121, 123 is composed of upper and lower arm switches and a capacitor. The switches of each full bridge circuit 121, 123 are semiconductor switching elements, specifically, N-channel MOSFETs. When operating the DC-DC converter 120, the motor control device 42 turns off each system main relay 130p, 130n.

[0185] In the first and second embodiments, the motor control device 42 may perform current feedback control so that the q-axis current is close to 0 while the torque of the motor 30 is within a range equal to or less than a predetermined value. For example, the predetermined value is a small torque that does not cause the user to feel uncomfortable. Even in this case, it is possible to prevent various inconveniences from occurring due to the torque of the motor 30 being generated while the storage battery 20 is being charged.

[0186] Each of the switches QUH to QWL, SH, and SL is not limited to an N-channel MOSFET, and may be, for example, an IGBT. In this case, the high-potential terminal of the IGBT (Insulated Gate Bipolar Transistor) becomes the collector, and the low-potential terminal becomes the emitter. A freewheel diode is connected in inverse parallel to each of the switches QUH to QWL, SH, and SL.

[0187] The phase windings of the motor 30 are not limited to being Y-connected, and may be delta-connected. In this case, the connection unit 70 can be configured to electrically connect the delta-connected phase windings to the single-phase AC power source 60. This makes it possible to use the motor 30 and the inverter 40 as part of a charger that charges the storage battery 20, even if the phase windings of the motor 30 are delta-connected.

[0188] The power storage unit to be charged by the external charger is not limited to a storage battery. For example, it may be a large-capacity electric double-layer capacitor, or may be one that includes both a storage battery and an electric double-layer capacitor.

[0189] The moving body on which the power conversion device is mounted is not limited to a vehicle, but may be, for example, an aircraft or a ship. The power conversion device is not limited to a moving body, but may be a stationary device.

[0190] The control device and the method described in the present disclosure may be realized by a special-purpose computer provided by configuring a processor and a memory programmed to execute one or more functions embodied in a computer program. Alternatively, the control device and the method described in the present disclosure may be realized by a special-purpose computer provided by configuring a processor with one or more dedicated hardware logic circuits. Alternatively, the control device and the method described in the present disclosure may be realized by one or more special-purpose computers configured by a combination of a processor and a memory programmed to execute one or more functions and a processor configured with one or more hardware logic circuits. In addition, the computer program may be stored in a computer-readable non-transitory tangible recording medium as instructions executed by the computer. [Explanation of symbols]

[0191] 10...power conversion device, 20...storage battery, 30...motor, 31U, 31V, 31W...U-, V-, and W-phase windings, 40...inverter, 60...single-phase AC power source, 70...connection portion.

Claims

1. A motor (30) having armature windings (31U, 31V, 31W); an inverter (40) that electrically connects the power storage unit (20) and the armature winding and controls a current flowing through the armature winding; In a power conversion device (10) comprising: a connection portion (70) that electrically connects one end of a single-phase AC power source (60) and the armature winding; a rectification unit (QUH, QUL, QVH, QVL, QWH, QWL, SH, SL) electrically connecting the other end of the single-phase AC power supply and the power storage unit, and rectifying an output current of the single-phase AC power supply so that a charging current flows from the single-phase AC power supply to the power storage unit; A power conversion device comprising:

2. the armature winding includes a first armature winding, a second armature winding, and a third armature winding as three-phase armature windings, The inverter has upper and lower arm switches (QUH, QVH, QWH, QUL, QVL, QWL) provided corresponding to the armature windings of each phase, a first end of the first armature winding, a first end of the second armature winding, and a first end of the third armature winding are electrically connected to connection points of the switches of the upper and lower arms in the corresponding phases; The connection unit is configured to be switchable between a motor drive state and an external charging state, the motor drive state is a state in which second ends of the armature windings are electrically connected to each other, the external charging state is a state in which one end of the single-phase AC power source is electrically connected to a second end side of the first armature winding, and the other end of the single-phase AC power source is electrically connected to a second end side of the second armature winding, 2. The power conversion device according to claim 1, wherein the rectifier unit is a switch of the upper and lower arms provided corresponding to the second armature winding in the external charging state, and is a switch whose switching is controlled in accordance with a polarity of an output voltage of the single-phase AC power supply.

3. 3. The power conversion device according to claim 2, wherein the connection unit has a change-over switch (71 a, 71 b, 71 c) configured to electrically connect the second end of the third armature winding to the second end of the first armature winding and to electrically disconnect the second end of the third armature winding from the second end of the second armature winding.

4. The connection portion is a first current path (73a) electrically connecting a second end side of the third armature winding to a second end side of the first armature winding; a second current path (73b) electrically connecting a second end side of the third armature winding to a second end side of the second armature winding, The power conversion device according to claim 3 , comprising, as the changeover switches, a first changeover switch (71 a) provided in the first current path and a second changeover switch (71 b) provided in the second current path.

5. 5. The power conversion device according to claim 4, further comprising a switching control unit that switches which of the first changeover switch and the second changeover switch to be turned on and which of the second changeover switch to be turned off in the external charging state based on an electrical angle of a rotor (32) of the motor.

6. 6. The power conversion device according to claim 5, further comprising a current control unit that performs switching control of the upper and lower arm switches connected to the first armature winding and the upper and lower arm switches connected to the third armature winding, based on the electrical angle, so that a q-axis current flowing through each of the armature windings has a value of 0 or near 0.

7. 7. The power conversion device according to claim 6, wherein the current control unit synchronizes switching control of the switches of the upper and lower arms connected to the first armature winding with switching control of the switches of the upper and lower arms connected to the third armature winding.

8. The power conversion device according to claim 7 , wherein the standard value of the output of the motor is greater than a time average value of the output power of the single-phase AC power source.

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