Control device for power converter, and program

Abstract

A control device (60) is applied to a system comprising: a rotary electric machine (20) that has armature windings (24U, 24V, 24W) and a magnetic field winding (22); a power storage unit (10) that stores drive power for the rotary electric machine; a first power converter (31) that is electrically connected to the armature windings and controls a current flowing through the armature windings; and a second power converter (33) that is electrically connected to the magnetic field winding and controls a current flowing through the magnetic field winding. The control device comprises: a first control unit that performs switching control of the first power converter so that a current flows from an AC power supply (41) to the power storage unit in a state where the AC power supply is electrically connected to the power storage unit via the armature windings and the first power converter; and a second control unit that performs switching control of the second power converter so that the torque of the rotary electric machine generated during the switching control of the first power converter is less than when a current does not flow to the magnetic field winding.

Description

Control device for power converter and program CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is based on Japanese Application No. 2023-105070, filed on June 27, 2023, the contents of which are incorporated herein by reference.

[0002] The present disclosure relates to a control device and a program for a power converter.

[0003] A conventional system includes a power storage unit, a power converter electrically connected to the power storage unit, and a rotating electric machine having an armature winding and a field winding electrically connected to the power converter. In this system, an AC power source is electrically connected to the power storage unit via the armature winding and the power converter, and the power storage unit is charged. When the power storage unit is being charged by the AC power source, the current flowing through the field winding is interrupted, thereby reducing the torque of the rotating electric machine. An example of such a technology is disclosed in Patent Document 1.

[0004] International Publication No. 2010 / 012924

[0005] Even if the power storage unit is charged by an AC power supply while current to the field winding is cut off, torque of the rotating electric machine may be generated due to current flowing through the armature winding. Various problems may arise due to the torque of the rotating electric machine being generated while the power storage unit is being charged.

[0006] A primary object of the present disclosure is to provide a control device and program for a power converter that can suppress various problems that may occur when torque is generated in a rotating electric machine during charging of a power storage unit.

[0007] The present disclosure provides a power converter control device applicable to a system including: a rotating electric machine having an armature winding and a field winding; an energy storage unit that stores drive power for the rotating electric machine; a first power converter electrically connected to the armature winding and controlling a current flowing through the armature winding; and a second power converter electrically connected to the field winding and controlling the current flowing through the field winding, the control device comprising: a first control unit that performs switching control of the first power converter so that current flows from an AC power source to the energy storage unit in a state where an AC power source is electrically connected to the energy storage unit via the armature winding and the first power converter; and a second control unit that performs switching control of the second power converter so that torque of the rotating electric machine generated during switching control of the first power converter is reduced compared to when no current flows through the field winding.

[0008] With the AC power supply electrically connected to the energy storage unit via the armature winding and the first power converter, switching control of the first power converter is performed so that current flows from the AC power supply to the energy storage unit, thereby charging the energy storage unit. In this case, the current flowing through the armature winding generates reluctance torque, which can cause various problems. In this regard, in a configuration in which the rotating electric machine has a field winding, it is possible to control the magnet torque generated by passing a current through the field winding and exciting the field winding. The supply of current to the field winding can be controlled by controlling the switching of the second power converter.

[0009] Therefore, in the present disclosure, the switching control of the second power converter is performed so that the torque generated by the rotating electric machine during the switching control of the first power converter is reduced compared to when no current flows through the field winding. As a result, the total torque of the magnet torque and the reluctance torque is reduced compared to when no current flows through the field winding. Therefore, it is possible to suppress the generation of torque from the rotating electric machine during charging of the power storage unit. As a result, it is possible to suppress the occurrence of inconveniences caused by the generation of torque from the rotating electric machine during charging of the power storage unit.

[0010] The above and other objects, features, and advantages of the present disclosure will become more apparent from the following detailed description taken in conjunction with the accompanying drawings, in which Fig. 1 is an overall configuration diagram of an in-vehicle system according to a first embodiment, Fig. 2 is a configuration diagram of a first coordinate conversion unit, Fig. 3 is a configuration diagram of a second coordinate conversion unit, Fig. 4 is a functional block diagram of three-phase charging control performed by a control device, Fig. 5 is a time chart showing an example of three-phase charging control, Fig. 6 is a diagram showing an example of three-phase charging control, Fig. 7 is a diagram for explaining torque reduction control, Fig. 8 is a diagram for explaining torque reduction control, Fig. 9 is a functional block diagram of torque reduction control performed by a control device, Fig. 10 is a time chart showing an example of torque reduction control, and Fig. 11 is a flow chart showing a processing procedure for external charging control. FIG. 12 is a time chart showing an example of external charging control, FIG. 13 is a time chart showing control of a comparative example, FIG. 14 is a time chart for explaining torque reduction control according to the second embodiment, FIG. 15 is a diagram showing a gear tooth strike mode according to a comparative example, FIG. 16 is a diagram showing a mode in which gear tooth strike is prevented, FIG. 17 is a time chart schematically showing the transition of rotor generated torque, FIG. 18 is a time chart showing an example of torque reduction control, FIG. 19 is an overall configuration diagram of an in-vehicle system according to another embodiment, and FIG. 20 is an overall configuration diagram of an in-vehicle system according to another embodiment.

[0011] A control device according to a first embodiment of the present disclosure will now be described with reference to the drawings. A system including the control device of the present embodiment is mounted on an electrically powered vehicle such as an electric vehicle or a hybrid vehicle.

[0012] As shown in Fig. 1, the system includes a storage battery 10 (corresponding to an "electricity storage unit") and a rotating electric machine 20. In this embodiment, the rotating electric machine 20 is a wound-field rotating electric machine. The rotating electric machine 20 of this embodiment is a rotating electric machine having forward salient polarity, in which the d-axis inductance Ld is larger than the q-axis inductance Lq.

[0013] The storage battery 10 is a power source that supplies driving power to the rotating electrical machine 20. The storage battery 10 is, for example, a battery pack including a series connection of unit cells. The unit cell is a single battery cell or a series connection of multiple battery cells. The battery cell is, for example, a secondary battery such as a lithium-ion battery.

[0014] The rotating electric machine 20 is a device that applies rotational power to the drive wheels 12 (corresponding to "rotationally driven objects") of a vehicle to rotate the drive wheels 12. The rotating electric machine 20 includes a rotor 21. The rotor 21 includes a rotor core and a plurality of field salient poles extending radially from the rotor core. A field winding 22 is wound around each of the field salient poles.

[0015] The system includes a power transmission mechanism 11. The rotating shaft of the rotor 21 is capable of transmitting power to drive wheels 12 of the vehicle via the power transmission mechanism 11. The power transmission mechanism 11 includes a transmission and a shaft. The transmission is, for example, a reduction gear and includes at least a pair of gears. Torque generated when the rotating electric machine 20 functions as an electric motor is transmitted to the drive wheels 12 via the power transmission mechanism 11, causing the drive wheels 12 to rotate. This causes the vehicle to travel.

[0016] The rotating electric machine 20 includes a stator 23. The stator 23 includes an armature core and an armature winding. The armature core includes an annular back yoke portion and a plurality of teeth extending radially from the back yoke portion toward the rotor 21. The armature winding includes U-, V-, and W-phase windings 24U, 24V, and 24W. The rotating electric machine 20 may be, for example, an in-wheel motor integrally provided on a drive wheel 12 of the vehicle, or an on-board motor provided on the body of the vehicle.

[0017] The system includes a power converter 30. The power converter 30 includes an inverter 31 and a field energization circuit 33. The inverter 31 converts DC current from the storage battery 10 into AC current and supplies the AC current to the armature winding 24. The inverter 31 includes a series connection of U-, V-, and W-phase upper arm switches SUH, SVH, and SWH and U-, V-, and W-phase lower arm switches SUL, SVL, and SWL.

[0018] The drains, which are high-potential terminals of the U-, V-, and W-phase upper arm switches SUH, SVH, and SWH, are connected to the positive terminal of the storage battery 10 via a high-potential electrical path Lp. The sources, which are low-potential terminals of the U-, V-, and W-phase lower arm switches SUL, SVL, and SWL, are connected to the negative terminal of the storage battery 10 via a low-potential electrical path Ln. Each electrical path Lp, Ln is a conductive member such as a bus bar.

[0019] In each phase, the connection points of the upper switches SUH, SVH, SWH and the lower switches SUL, SVL, SWL are electrically connected to first ends of the windings 24U, 24V, 24W. Second ends of the U-, V-, and W-phase windings 24U, 24V, 24W are connectable to one another.

[0020] The inverter 31 includes a first capacitor 32, which is a smoothing capacitor. The first capacitor 32 may be provided outside the inverter 31.

[0021] The field energization circuit 33 supplies current from the storage battery 10 to the field winding 22. The field energization circuit 33 is a full-bridge circuit, and includes a series connection of a first upper arm switch SH1 and a first lower arm switch SL1, and a series connection of a second upper arm switch SH2 and a second lower arm switch SL2.

[0022] The drains, which are high-potential terminals of the first and second upper-arm switches SH1 and SH2, are connected to the positive terminal of the storage battery 10 via a high-potential electrical path Lp. The sources, which are low-potential terminals of the first and second lower-arm switches SL1 and SL2, are connected to the negative terminal of the storage battery 10 via a low-potential electrical path Ln. A first end of the field winding 22 is connected to the connection point between the first upper-arm switch SH1 and the first lower-arm switch SL1 via a brush (not shown). A second end of the field winding 22 is connected to the connection point between the second upper-arm switch SH2 and the second lower-arm switch SL2 via a brush (not shown).

[0023] In this embodiment, the switches SUH to SWL and SH1 to SL2 are bidirectional switching elements that, when turned on, allow current to flow from drain to source and from source to drain. For example, the switches SUH to SWL and SH1 to SL2 are N-channel metal oxide semiconductor field effect transistors (MOSFETs). The switches SUH, SVH, SWH, SUL, SVL, SWL, SH1, SH2, SL1, and SL2 are each equipped with a body diode DUH, DVH, DWH, DUL, DVL, DWL, DH1, DH2, DL1, and DL2. The inverter 31 corresponds to the "first power converter," and the field energization circuit 33 corresponds to the "second power converter."

[0024] The field energization circuit 33 includes a second capacitor 34, which is a smoothing capacitor. The second capacitor 34 may be provided outside the field energization circuit 33. Alternatively, instead of the configuration in which the second capacitor 34 is provided individually in the field energization circuit 33 and the first capacitor 32 is provided individually in the inverter 31, a configuration in which a common capacitor is provided to the inverter 31 and the field energization circuit 33 may be used. In this case, for example, the second capacitor 34 may not be provided.

[0025] The system includes a high-potential-side main switch 40p and a low-potential-side main switch 40n. Each of the main switches 40p, 40n is a switch for electrically connecting or disconnecting the storage battery 10 and the power converter 30. The high-potential-side main switch 40p is provided on the high-potential-side electrical path Lp, and the low-potential-side main switch 40n is provided on the low-potential-side electrical path Ln. Each of the main switches 40p, 40n blocks bidirectional current flow when turned off and allows bidirectional current flow when turned on. For example, each of the main switches 40p, 40n is a mechanical relay or a semiconductor switching element.

[0026] The system includes a three-phase AC power supply 41. The three-phase AC power supply 41 is, for example, a system power supply. In the three-phase AC power supply 41, the amplitude and frequency of the output voltage of each phase are the same, and the phases of the output voltage and output current are shifted by 120° for each phase. The three-phase AC power supply 41 constitutes an external charger capable of charging the storage battery 10. The external charger is provided outside the vehicle and is, for example, a stationary charger.

[0027] The system includes U-, V-, and W-phase charging paths 25U, 25V, and 25W, an input switch 42 (corresponding to a "changeover switch"), a filter 43, and a neutral switch. In each phase, the second ends of windings 24U, 24V, and 24W are electrically connectable to a three-phase AC power supply 41 via charging paths 25U, 25V, and 25W. Filter 43 removes noise transmitted through each charging path 25U, 25V, and 25W. Filter 43 is provided to meet EMC standard requirements.

[0028] The input switch 42 is provided in each of the charging paths 25U, 25V, 25W closer to the three-phase AC power supply 41 than the filter 43. Each input switch 42 is turned on when the storage battery 10 is being charged by the three-phase AC power supply 41, and is turned off when the storage battery 10 is not being charged or when the three-phase AC power supply 41 is not connected to each of the phase windings 24U, 24V, 24W. The provision of each input switch 42 makes it possible to realize a configuration suitable for electrically connecting or disconnecting each of the phase windings 24U, 24V, 24W and the three-phase AC power supply 41.

[0029] The neutral point switches are switches that switch the electrical connection of the second ends of the phase windings 24U, 24V, and 24W. In this embodiment, the neutral point switches include a U-phase neutral point switch 44a that electrically connects or disconnects the U-phase charging path 25U and the V-phase charging path 25V, and a V-phase neutral point switch 44b that electrically connects or disconnects the V-phase charging path 25V and the W-phase charging path 25W.

[0030] When the neutral point switches 44a and 44b are turned on, the second ends of the phase windings 24U, 24V, and 24W are electrically connected to each other. In this case, the phase windings 24U, 24V, and 24W are star-connected with a 120° electrical angle offset from each other. This enables the rotating electric machine 20 to be rotated.

[0031] On the other hand, by turning off each of the neutral point switches 44a, 44b, the second ends of the respective phase windings 24U, 24V, 24W are electrically disconnected from each other. In this case, in each phase, the second ends of the windings 24U, 24V, 24W are electrically connected to the three-phase AC power supply 41 via the charging paths 25U, 25V, 25W, thereby enabling the storage battery 10 to be charged by the three-phase AC power supply 41. Therefore, by providing each of the neutral point switches 44a, 44b, it is possible to switch between a state in which the rotating electric machine 20 is rotationally driven and a state in which the rotating electric machine 20 is used as part of a charger for the storage battery 10.

[0032] When turned off, each of the input switches 42 and neutral point switches 44 a, 44 b blocks the flow of current in both directions, and when turned on, allows the flow of current in both directions. For example, each of the input switches 42 and neutral point switches 44 a, 44 b is a mechanical relay or a semiconductor switching element.

[0033] The system includes a voltage sensor 50, a phase current sensor 51, a field current sensor 52, an angle sensor 53, and a phase voltage sensor 54. The voltage sensor 50 detects the voltage of the storage battery 10. The phase current sensor 51 detects the phase current flowing in at least two of the U-, V-, and W-phase windings 24U, 24V, and 24W. The field current sensor 52 detects the field current flowing in the field winding 22. The angle sensor 53 detects the rotation angle (specifically, the electrical angle) of the rotor 21. The phase voltage sensor 54 detects the phase voltage of each of the phase windings 24U, 24V, and 24W.

[0034] The system includes a control device 60 and a host control device 70 that is higher in level than the control device 60. The detection values ​​of the sensors 50 to 54 are input to the control device 60.

[0035] The control device 60 is an electronic control unit (ECU) mainly composed of a microcomputer 60a. The host control device 70 is an ECU also mainly composed of a microcomputer. The control device 60 and the host control device 70 are capable of exchanging information.

[0036] The microcomputer 60a includes a CPU (Central Processing Unit). The functions provided by the microcomputer 60a can be provided by software stored in a physical memory device and a computer executing the software, software alone, hardware alone, or a combination thereof. For example, if the microcomputer 60a is provided by a hardware electronic circuit, the functions can be provided by a digital circuit including multiple logic circuits or an analog circuit. For example, the microcomputer 60a executes a program stored in a non-transitory tangible storage medium serving as its own storage unit. The program includes, for example, a program for the process shown in FIG. 11 (described later). A set of instructions constituting the program is executed to perform a method corresponding to 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, via OTA (Over the Air).

[0037] The control device 60 controls the main switches 40p, 40n, the input switch 42, and the neutral point switches 44a, 44b. Specifically, when driving the rotating electric machine 20 to run the vehicle, the control device 60 turns on the main switches 40p, 40n and the neutral point switches 44a, 44b and turns off the input switch 42.

[0038] The control device 60 performs switching control of the switches SH1 to SL2 that constitute the field energization circuit 33 to excite the field winding 22. More specifically, the control device 60 performs switching control so that a first state and a second state alternate, in order to control the field current detected by the field current sensor 52 to a field target current. The first state is a state in which the first upper arm switch SH1 and the second lower arm switch SL2 are turned on, and the second upper arm switch SH2 and the first lower arm switch SL1 are turned off. The second state is a state in which the first upper arm switch SH1 and the second lower arm switch SL2 are turned off, and the second upper arm switch SH2 and the first lower arm switch SL1 are turned on.

[0039] While the field winding 22 is excited, the control device 60 performs switching control of the switches SUH to SWL constituting the inverter 31 to feedback control the control variable of the rotating electric machine 20 to a command value based on the detection values ​​of the sensors 50 to 54. In this embodiment, the control variable is torque. In each phase, the upper arm switch and the lower arm switch are alternately turned on. This feedback control transmits the rotational power of the rotor 21 to the drive wheels 12, causing the vehicle to run.

[0040] Next, external charging control for charging the storage battery 10 using the three-phase AC power supply 41 will be described.

[0041] When performing external charging control, the control device 60 turns on the main switches 40p, 40n and the input switch 42 and turns off the neutral point switches 44a, 44b. During external charging control, the control device 60 performs switching control of the inverter 31 to convert AC power from the three-phase AC power supply 41 into DC power. The converted DC power is supplied to the storage battery 10, and the storage battery 10 is charged.

[0042] During external charging control, current flows through the phase windings 24U, 24V, and 24W, which can generate torque in the rotating electric machine 20. In this case, various problems can arise due to the torque generated by the rotating electric machine 20 while the storage battery 10 is being charged.

[0043] For example, the rotating electric machine 20 may be made multipolar, or the length of the rotating electric machine 20 in the direction of the rotation axis (i.e., stacking depth) and the length of the rotating electric machine 20 in the radial direction perpendicular to the rotation axis (i.e., outer diameter) may be increased to increase the output of the rotating electric machine 20. As a result, the torque of the rotating electric machine 20 generated by current flowing through the U-, V-, and W-phase windings 24U, 24V, and 24W increases. In this case, there is a concern that problems such as unintended rotation of the drive wheels 12 may occur when the storage battery 10 is being charged.

[0044] Therefore, in this embodiment, the control device 60 performs three-phase charging control and torque reduction control during external charging control. In the three-phase charging control, switching control of the inverter 31 is performed so that current flows from the three-phase AC power supply 41 to the storage battery 10. In the torque reduction control, switching control of the field energization circuit 33 is performed so that the torque of the rotating electric machine 20 generated during the three-phase charging control is reduced compared to when no current flows through the field winding 22.

[0045] The three-phase charging control and torque reduction control will be described in detail below.

[0046] In the three-phase charging control and torque reduction control, switching control is performed based on currents obtained by converting U-, V-, and W-phase currents in a three-phase fixed coordinate system into a two-phase rotating coordinate system (dq coordinate system). In the three-phase charging control, switching control of the inverter 31 is performed based on currents converted into the first dq coordinate system. Phase information of the input voltage input from the three-phase AC power supply 41 to each of the phase windings 24U, 24V, and 24W is used as periodically varying phase information for converting the U-, V-, and W-phase currents between the first dq coordinate system and the three-phase fixed coordinate system.

[0047] In the torque reduction control, switching control of the field energization circuit 33 is performed based on the current converted into the second dq coordinate system. The electrical angle θe of the rotor 21 is used as periodically varying phase information to convert the U-, V-, and W-phase currents between the second dq coordinate system and the three-phase fixed coordinate system.

[0048] 2 and 3, the control device 60 includes a first coordinate conversion unit 100 and a second coordinate conversion unit 110. The first coordinate conversion unit 100 converts the current and voltage used in the three-phase charging control into a current and voltage in a first dq coordinate system. The second coordinate conversion unit 110 converts the current used in the torque reduction control into a current in a second dq coordinate system.

[0049] Specifically, the first coordinate conversion unit 100 includes a first phase acquisition unit 101, a first current conversion unit 102, and a voltage conversion unit 103. The first phase acquisition unit 101 receives a U-phase voltage Vu. The U-phase voltage Vu is an input voltage input from the three-phase AC power supply 41 to the U-phase winding 24U. The first phase acquisition unit 101 can use the detected value of the phase voltage sensor 54 as the U-phase voltage Vu. The first phase acquisition unit 101 acquires phase information θa of the U-phase voltage Vu. The phase information θa of the U-phase voltage Vu fluctuates with the same period as the U-phase voltage Vu and fluctuates within a range of 0° to 360°. For example, the phase information θa can be determined such that the zero-up cross timing of the U-phase voltage Vu is 0° and the next zero-up cross timing of the U-phase voltage Vu is 360°. The first phase acquisition unit 101 is configured, for example, with a phase locked loop circuit.

[0050] The first current converter 102 receives phase information θa of the U-phase voltage Vu and the U-, V-, and W-phase currents Iu, Iv, and Iw acquired by the first phase acquisition unit 101. The first current converter 102 can use detection values ​​of the phase current sensor 51 as the U-, V-, and W-phase currents Iu, Iv, and Iw. The first current converter 102 converts the U-, V-, and W-phase currents Iu, Iv, and Iw into a first d-axis current id1 and a first q-axis current iq1 based on the phase information θa of the U-phase voltage Vu.

[0051] The voltage converter 103 receives the phase information θa acquired by the first phase acquisition unit 101 and the U-, V-, and W-phase voltages Vu, Vv, and Vw. The voltage converter 103 can use the detection values ​​of the phase voltage sensor 54 as the phase voltages Vu, Vv, and Vw. Based on the phase information θa, the voltage converter 103 converts the U-, V-, and W-phase voltages Vu, Vv, and Vw into d- and q-axis input voltages Esd and Esq.

[0052] The second coordinate conversion unit 110 has a second phase acquisition unit 111 and a second current conversion unit 112. The detection value of the angle sensor 53 is input to the second phase acquisition unit 111. The second phase acquisition unit 111 acquires the detection value of the angle sensor 53 as the electrical angle θe of the rotor 21.

[0053] The second current converter 112 receives the electrical angle θe of the rotor 21 acquired by the second phase acquirer 111 and the U-, V-, and W-phase currents Iu, Iv, and Iw. The second current converter 112 can use the detection values ​​of the phase current sensor 51 as the U-, V-, and W-phase currents Iu, Iv, and Iw. The second current converter 112 converts the U-, V-, and W-phase currents Iu, Iv, and Iw into a second d-axis current id2 and a second q-axis current iq2 based on the electrical angle θe of the rotor 21.

[0054] Next, the three-phase charging control will be specifically described with reference to FIG.

[0055] The control device 60 includes a command current setting unit 80 that sets a d-axis command current id* and a q-axis command current iq*. The command current setting unit 80 sets the d-axis command current id* to 0. The command current setting unit 80 sets the q-axis command current iq* based on the voltage on the DC side of the power converter 30.

[0056] More specifically, the command current setting unit 80 includes a limiting unit 81, a voltage deviation calculation unit 82, and a voltage feedback control unit 83. A reference voltage VDCref for the DC side voltage of the power converter 30 is input to the limiting unit 81. For example, the limiting unit 81 can use a voltage value set by the higher-level control device 70 as the reference voltage VDCref. If the reference voltage VDCref is outside a predetermined voltage range, the limiting unit 81 limits the reference voltage VDCref to the upper or lower limit of the voltage range. The limiting unit 81 outputs the reference voltage VDCref to the voltage deviation calculation unit 82.

[0057] The voltage deviation calculation unit 82 calculates the voltage deviation ΔV by subtracting the power supply voltage VDC from the reference voltage VDCref. The voltage deviation calculation unit 82 can use the detection value of the voltage sensor 50 as the power supply voltage VDC. The voltage deviation calculation unit 82 outputs the voltage deviation ΔV to the voltage feedback control unit 83.

[0058] The voltage feedback control unit 83 calculates the q-axis command current iq* as a manipulated variable for feedback controlling the voltage deviation ΔV to 0. The feedback control used by the voltage feedback control unit 83 may be, for example, proportional-integral control.

[0059] The command current setting unit 80 sets the q-axis command current iq* calculated by the voltage feedback control unit 83 and the d-axis command current id*, which is 0, as command currents for the respective phase windings 24U, 24V, and 24W.

[0060] The control device 60 includes a q-axis current deviation calculation unit 84a and a d-axis current deviation calculation unit 84b. The q-axis current deviation calculation unit 84a receives the q-axis command current iq* set by the command current setting unit 80 and the first q-axis current iq1 converted by the first current conversion unit 102. The q-axis current deviation calculation unit 84a calculates the q-axis current deviation Δiq by subtracting the first q-axis current iq1 from the q-axis command current iq*.

[0061] The d-axis current deviation calculation unit 84b receives the d-axis command current id* set by the command current setting unit 80 and the first d-axis current id1 converted by the first current conversion unit 102. The d-axis current deviation calculation unit 84b calculates the d-axis current deviation Δid by subtracting the first d-axis current id1 from the d-axis command current id*.

[0062] The control device 60 includes a q-axis current feedback control unit 85a and a d-axis current feedback control unit 85b. The q-axis current feedback control unit 85a calculates a q-axis command voltage Vq as a manipulated variable for feedback-controlling the q-axis current deviation Δiq to zero. The d-axis current feedback control unit 85b calculates a d-axis command voltage Vd as a manipulated variable for feedback-controlling the d-axis current deviation Δid to zero. The feedback control used by each of the feedback control units 85a, 85b may be, for example, proportional-integral control.

[0063] The control device 60 includes a non-interference control unit 86. The non-interference control unit 86 corrects the d-axis and q-axis command voltages Vd and Vq in consideration of electromotive forces that are generated so as to interfere with components of different axes among the d-axis and the q-axis.

[0064] Specifically, the decoupling control unit 86 includes a q-axis decoupling term calculation unit 86a and a q-axis decoupling term addition unit 86b. The q-axis decoupling term calculation unit 86a calculates a q-axis decoupling term "ω·Ld·id" by multiplying the first d-axis current id1 converted by the first current conversion unit 102, the d-axis inductance Ld, and the angular velocity ω. Here, the angular velocity ω is expressed as ω = 2π × f, where f is the frequency of the U-, V-, and W-phase voltages Vu, Vv, and Vw. The frequency of the U-, V-, and W-phase voltages Vu, Vv, and Vw is, for example, 50 Hz. The q-axis decoupling term addition unit 86b adds the q-axis decoupling term calculated by the q-axis decoupling term calculation unit 86a to the q-axis command voltage Vq calculated by the q-axis current feedback control unit 85a.

[0065] The decoupling control unit 86 also has a d-axis decoupling term calculation unit 86c and a d-axis decoupling term subtraction unit 86d. The d-axis decoupling term calculation unit 86c calculates a d-axis decoupling term "ω·Lq·iq" as a value obtained by multiplying the first q-axis current iq, the q-axis inductance Lq, and the angular velocity ω converted by the first current conversion unit 102. The d-axis decoupling term subtraction unit 86d subtracts the d-axis decoupling term calculated by the d-axis decoupling term calculation unit 86c from the d-axis command voltage Vd calculated by the d-axis current feedback control unit 85b.

[0066] The d-axis inductance Ld and the q-axis inductance Lq vary depending on the U-, V-, and W-phase currents Iu, Iv, and Iw, the field current, and the electrical angle θe of the rotor 21. Therefore, the q-axis decoupling term calculation unit 86a may use, as the d-axis inductance Ld, a value calculated based on at least one of the U-, V-, and W-phase currents Iu, Iv, and Iw, the field current, and the electrical angle θe of the rotor 21. Furthermore, the d-axis decoupling term calculation unit 86c may use, as the q-axis inductance Lq, a value calculated based on at least one of the U-, V-, and W-phase currents Iu, Iv, and Iw, the field current, and the electrical angle θe of the rotor 21. The calculation of each axis inductance Ld, Lq may use information (specifically, map information or formula information) that associates the d-axis inductance Ld or the q-axis inductance Lq with at least one of the U-, V-, and W-phase currents Iu, Iv, and Iw, the field current, and the electrical angle θe of the rotor 21.

[0067] The control device 60 includes a q-axis feedforward control unit 87a and a d-axis feedforward control unit 87b. The q-axis feedforward control unit 87a receives as input a q-axis input voltage Esq converted by a voltage conversion unit 103 and a q-axis command voltage Vq corrected by a q-axis non-interference term adder 86b. The q-axis feedforward control unit 87a adds the q-axis input voltage Esq as a feedforward term to the q-axis command voltage Vq. The d-axis feedforward control unit 87b receives as input a d-axis input voltage Esd converted by the voltage conversion unit 103 and a d-axis command voltage Vd corrected by a d-axis non-interference term subtracter 86d. The d-axis feedforward control unit 87b adds the d-axis input voltage Esd as a feedforward term to the d-axis command voltage Vd.

[0068] The control device 60 includes a fixed coordinate conversion unit 88. The fixed coordinate conversion unit 88 receives the d- and q-axis command voltages Vd and Vq calculated by the d- and q-axis feedforward control units 87a and 87b, and phase information θa from a first phase acquisition unit 101. The fixed coordinate conversion unit 88 converts the d- and q-axis command voltages Vd and Vq into U-, V-, and W-phase command voltages Vu*, Vv*, and Vw* based on the phase information θa.

[0069] The control device 60 includes a modulator 89, a comparator 90, and an inverter 91. The modulator 89 receives the power supply voltage VDC and the U-, V-, and W-phase command voltages Vu*, Vv*, and Vw* from the fixed coordinate converter 88. The modulator 89 superimposes a third harmonic on the command voltages Vu*, Vv*, and Vw* for each phase. The modulator 89 then calculates modulation factors Mu, Mv, and Mw for each phase by dividing the command voltages Vu*, Vv*, and Vw* by the power supply voltage VDC. The modulator 89 can use the detection value of the voltage sensor 50 as the power supply voltage VDC.

[0070] The comparator 90 receives the modulation factors Mu, Mv, and Mw of each phase from the modulator 89. The comparator 90 generates operation signals for the lower-arm switches SUL, SVL, and SWL in the inverter 31 based on a magnitude comparison between the modulation factors Mu, Mv, and Mw of each phase and the carrier signal. The operation signals for the lower-arm switches SUL, SVL, and SWL are ON operation signals or OFF operation signals. The inverter 91 inverts the logic of the operation signals for the lower-arm switches SUL, SVL, and SWL of each phase to generate operation signals for the upper-arm switches SUH, SVH, and SWL of each phase. The carrier signal is, for example, a triangular wave signal.

[0071] 5 and 6 show examples of voltage and current control when the above-described three-phase charging control is performed. In FIG. 5, (a) shows the transitions of the phase voltages Vu, Vv, and Vw, (b) shows the transitions of the phase currents Iu, Iv, and Iw, (c) shows the phase information θa of the U-phase voltage Vu, (d) shows the transitions of the first d-axis current id1, and (e) shows the transitions of the first q-axis current iq1. FIG. 6 shows, in the first dq coordinate system, a voltage vector V determined from the phase voltages Vu, Vv, and Vw and a current vector i flowing through each of the phase windings 24U, 24V, and 24W. Note that in FIG. 5(b), the direction of current flow from the first end to the second end of each of the phase windings 24U, 24V, and 24W is defined as positive, and the direction of current flow from the second end to the first end of each of the phase windings 24U, 24V, and 24W is defined as negative.

[0072] For the transformation from the three-phase fixed coordinate system to the first dq coordinate system, the first coordinate transformation unit 100 uses phase information θa that periodically varies with the same period T as the U-phase voltage Vu. In this case, the first coordinate transformation unit 100 can perform the transformation from the three-phase fixed coordinate system to the first dq coordinate system based on the phase information θa so that the direction of the voltage vector V determined from the phase voltages Vu, Vv, and Vw is oriented in the q-axis direction in the first dq coordinate system.

[0073] The command current setting unit 80 sets the d-axis command current id* and the q-axis command current iq* so that the currents flowing through the phase windings 24U, 24V, and 24W are oriented in the q-axis direction in the first dq coordinate system. That is, the command current setting unit 80 sets the d-axis command current id* and the q-axis command current iq* so that the directions of the first d- and q-axis currents id1 and iq1 are aligned with the direction of the voltage vector V determined by the phase voltages Vu, Vv, and Vw in the first dq coordinate system. In this embodiment, the command current setting unit 80 sets the d-axis command current id* to 0 and sets the q-axis command current iq* to a value corresponding to the power supply voltage VDC.

[0074] Current feedback control of the first d- and q-axis currents id1 and iq1 is performed based on the d- and q-axis command currents id* and iq* set by the command current setting unit 80, thereby controlling the phase currents Iu, Iv, and Iw to have waveforms in phase with the phase voltages Vu, Vv, and Vw. In other words, in the first dq coordinate system, the direction of the current vector i flowing through the phase windings 24U, 24V, and 24W is controlled to the q-axis direction, which is the same direction as the voltage vector V determined from the phase voltages Vu, Vv, and Vw. This allows the power factor determined from the voltage vector V and the current vector i to approach 1, thereby improving the charging efficiency of the storage battery 10.

[0075] Next, the torque reduction control will be described.

[0076] In torque reduction control, switching control of the field energizing circuit 33 is performed so that the torque of the rotating electric machine 20 generated during three-phase charging control is reduced compared to when no current flows through the field winding 22.

[0077] Specifically, the torque Trq generated by the rotary electric machine 20 is made up of a magnet torque TM and a reluctance torque TR. When the magnet torque TM and the reluctance torque TR are expressed using the second d-axis and q-axis currents id2 and iq2, the following equation (eq1) is obtained.

[0078] Trq = TM + TR = P φf iq2 + P (Ld - Lq) id2 iq2 ... (eq1) Here, in the above equation (eq1), P represents the number of pole pairs of the rotating electric machine 20, and φf represents the magnetic flux generated when the field current If flows through the field winding 22. When the coupling inductance Lmf is used, the magnetic flux φf can be expressed as "φf = Lmf × If." The coupling inductance Lmf (>0) is the inductance of the d-axis magnetic path that includes the back yoke portion and teeth portion of the stator 23 and the rotor core and field salient pole portion of the rotor 21.

[0079] In torque reduction control, the magnet torque TM is controlled by controlling the supply of current to the field winding 22. In this case, the magnet torque TM is generated so that the total torque of the reluctance torque TR and the magnet torque TM is reduced compared to when no current is passed through the field winding 22. For example, to pass a current through the field winding 22 so that the reluctance torque TR and the magnet torque TM cancel each other out, it is sufficient to pass a field current If so that the torque Trq generated by the rotating electric machine 20 in the above equation (eq1) becomes 0. In this case, the field current If should be as shown in the following equation (eq2):

[0080] In this embodiment, the rotating electric machine 20 has forward salient polarity, and Ld - Lq > 0. Therefore, in the above equation (eq2), the field current If is a current whose phase is 180° out of phase with the second d-axis current id2.

[0081] Here, the field current If flowing through the field winding 22 during torque reduction control will be described with reference to FIGS.

[0082] 7 and 8 , the current vector Ia flowing through each of the phase windings 24U, 24V, and 24W during three-phase charging control is schematically shown in the second dq coordinate system. In the second dq coordinate system, the current vector Ia rotates at the frequency of each of the phase voltages Vu, Vv, and Vw input from the three-phase AC power supply 41. Therefore, the second d-axis current id2, which is the d-axis component of the current vector Ia flowing through each of the phase windings 24U, 24V, and 24W, is an AC current in the second dq coordinate system. In this embodiment, the rotating electric machine 20 has forward salient polarity (Ld−Lq>0). Therefore, during torque reduction control, the control device 60 performs switching control of the field energization circuit 33 so as to cause a current that is opposite in phase to the second d-axis current id2 to flow as the field current If.

[0083] For example, as shown in Fig. 7, when the second d-axis current id2 is positive, the control device 60 controls the switching of the field energization circuit 33 so that the field current If in the second dq coordinate system is generated in the negative d-axis direction. For example, as shown in Fig. 8, when the second d-axis current id2 is negative, the control device 60 controls the switching of the field energization circuit 33 so that the field current If in the second dq coordinate system is generated in the positive d-axis direction.

[0084] The torque reduction control will be specifically described with reference to FIG.

[0085] The control device 60 includes a target current setting unit 120. The second d-axis current id2 is input to the target current setting unit 120 from the second coordinate transformation unit 110. In this embodiment, the rotating electric machine 20 has forward salient polarity (Ld - Lq > 0). Therefore, the target current setting unit 120 sets a current that is opposite in phase to the second d-axis current id2 as the field target current If*. This allows the characteristics of the rotating electric machine 20 to be taken into consideration, and allows the field current If to flow so that the magnet torque TM is generated in the direction opposite to the direction in which the reluctance torque TR is generated. Therefore, during torque reduction control, the magnet torque TM can be accurately generated so that the total torque of the reluctance torque TR and the magnet torque TM is reduced compared to when no current is flowing through the field winding 22.

[0086] Specifically, the target current setting unit 120 sets the field target current If* using information (specifically, map information or formula information) that associates the second d-axis current id2 with the field target current If*.

[0087] For example, the target current setting unit 120 can set the field target current If* based on the second d-axis current id2, the d- and q-axis inductances Ld and Lq, and the coupling inductance Lmf. In this case, the target current setting unit 120 calculates the right-hand side of the above equation (eq2) based on the second d-axis current id2, the d- and q-axis inductances Ld and Lq, and the coupling inductance Lmf input from the second current converter 112, and sets the calculated value as the field target current If*.

[0088] The target current setting unit 120 can use values ​​calculated using map information or mathematical formula information as the d-axis and q-axis inductances Ld and Lq and the coupling inductance Lmf.

[0089] For example, the d-axis inductance Ld can be calculated from map information in which the second d-axis current id2, the field current If, the electrical angle θe, and the d-axis inductance Ld are associated with each other, the second d-axis current id2 input from the second coordinate conversion unit 110, the detected value of the field current sensor 52, and the electrical angle θe acquired by the second phase acquisition unit 111. For example, the q-axis inductance Lq can be calculated from map information in which the second q-axis current iq2, the electrical angle θe, and the q-axis inductance Lq are associated with each other, the second q-axis current iq2 input from the second coordinate conversion unit 110, and the electrical angle θe acquired by the second phase acquisition unit 111. For example, the coupling inductance Lmf can be calculated based on map information correlating the second d- and q-axis currents id2, iq2, the field current If, the electrical angle θe, and the coupling inductance Lmf, the second d- and q-axis currents id2, iq2 input from the second coordinate conversion unit 110, the detection value of the field current sensor 52, and the electrical angle θe acquired by the second phase acquisition unit 111.

[0090] The control device 60 includes a field current deviation calculation unit 121 and a field current feedback control unit 122. The field current deviation calculation unit 121 receives the field target current If* set by the target current setting unit 120 and the field current If. The field current deviation calculation unit 121 can use the detection value of the field current sensor 52 as the field current If. The field current deviation calculation unit 121 calculates the field current deviation ΔIf by subtracting the field current If from the field target current If*. The field current deviation calculation unit 121 outputs the calculated field current deviation ΔIf to the field current feedback control unit 122.

[0091] The field current feedback control unit 122 calculates a field command voltage Vf as a manipulated variable for feedback controlling the field current deviation ΔIf to 0. The feedback control used by the voltage feedback control unit 83 may be, for example, proportional-integral control.

[0092] The control device 60 includes a divider 123, a comparator 124, and an inverter 125. The divider 123 receives the field command voltage Vf from the field current feedback control unit 122. The divider 123 calculates the field modulation factor Mf by dividing the field command voltage Vf by the power supply voltage VDC. The divider 123 can use the detection value of the voltage sensor 50 as the power supply voltage VDC.

[0093] The comparator 124 receives the field modulation factor Mf from the divider 123. The comparator 124 generates operation signals for the first upper arm switch SH1 and the second lower arm switch SL2 based on a magnitude comparison between the field modulation factor Mf and the carrier signal. The operation signals for the first upper arm switch SH1 and the second lower arm switch SL2 are ON operation signals or OFF operation signals. The inverter 125 inverts the logic of the operation signals for the first upper arm switch SH1 and the second lower arm switch SL2 to generate operation signals for the first lower arm switch SL1 and the second upper arm switch SH2. The carrier signal is, for example, a triangular wave signal.

[0094] 10 shows the transition of each current when the torque reduction control described above is performed, where (a) shows the electrical angle θe of the rotor 21, (b) shows the transition of the second d-axis current id2, (c) shows the transition of the second q-axis current iq2, and (d) shows the transition of the field current If.

[0095] The second d-axis current id2 and the second q-axis current iq2 are AC currents that periodically fluctuate with the same cycle T as the U-phase voltage Vu. The field current If is controlled to be an AC current of opposite phase to the second d-axis current id2. FIG. 10 illustrates a case where the phase difference θs between the field current If and the second d-axis current id2 is 180°. For example, when the phase difference θs is 180°, the phase of the field current If is advanced relative to the second d-axis current id2 by an amount corresponding to the period from the zero-upcrossing timing of the second d-axis current id2 to the next zero-downcrossing timing. By controlling the field current If to be an AC current of opposite phase to the second d-axis current id2, the magnet torque TM is generated so that the total torque of the reluctance torque TR and the magnet torque TM is reduced compared to when no current flows through the field winding 22. This suppresses fluctuations in the electrical angle θe of the rotor 21.

[0096] 11 shows a processing procedure for external charging control performed by the control device 60. The external charging control is performed, for example, based on a command from a higher-level control device 70. Here, the description will be given assuming that the second ends of the phase windings 24U, 24V, 24W are electrically connected to the three-phase AC power supply 41, that the input switch 42 is turned on, and that the neutral point switches 44a, 44b are turned off.

[0097] In step S10, it is determined whether or not three-phase charging control is to be performed. For example, if a command to perform external charging control has been transmitted from the upper control device 70, it is determined that three-phase charging control is to be performed. If the determination in step S10 is negative, this control is terminated. On the other hand, if the determination in step S10 is positive, the process proceeds to step S11.

[0098] In step S11, the frequency f of each phase voltage Vu, Vv, Vw input from the three-phase AC power supply 41 to each phase winding 24U, 24V, 24W and the reference voltage VDCref for the voltage on the DC side of the power converter 30 are acquired. Information transmitted from the three-phase AC power supply 41 can be acquired as the frequency f. Information transmitted from the upper control device 70 can be acquired as the reference voltage VDCref.

[0099] In step S12, the phase currents Iu, Iv, Iw and the phase voltages Vu, Vv, Vw are obtained as the currents and voltages input to the phase windings 24U, 24V, 24W from the three-phase AC power supply 41. The detected values ​​of the phase current sensors 51 can be obtained as the phase currents Iu, Iv, Iw. The detected values ​​of the phase voltage sensors 54 can be obtained as the phase voltages Vu, Vv, Vw.

[0100] In step S13, the control device 60 acquires phase information θa based on the U-phase voltage Vu. In this case, the control device 60 functions as the first phase acquisition unit 101 described above with reference to Fig. 2. The control device 60 also acquires the detection value of the voltage sensor 50 as the power supply voltage VDC.

[0101] In step S14, a command current is set. In this embodiment, the d-axis command current id* is set to 0, and the q-axis command current iq* is set based on the reference voltage VDCref and the power supply voltage VDC. In this case, the control device 60 functions as the command current setting unit 80 described above with reference to FIG. 4.

[0102] In step S15, the control device 60 converts the phase currents Iu, Iv, Iw into first d-axis and q-axis currents id1 and iq1, and converts the phase voltages Vu, Vv, Vw into d-axis and q-axis input voltages Esd and Esq based on the phase information θa. In this case, the control device 60 functions as the first coordinate converter 100 described above with reference to FIG.

[0103] In step S16, feedback control of the first d- and q-axis currents id1 and iq1 is performed based on the command currents. Here, the d- and q-axis command voltages Vd and Vq are calculated. In this case, the control device 60 functions as the q-axis current deviation calculation unit 84a, the d-axis current deviation calculation unit 84b, the q-axis current feedback control unit 85a, and the d-axis current feedback control unit 85b described above in FIG.

[0104] In step S17, d-q axis decoupling control is performed based on the d- and q-axis command voltages Vd and Vq, the frequency f, and the d- and q-axis inductances Ld and Lq. Values ​​calculated based on at least one of the U-, V-, and W-phase currents Iu, Iv, and Iw, the field current If, and the electrical angle θe of the rotor 21 can be used as the d- and q-axis inductances Ld and Lq. In the processing of step S17, the control device 60 functions as the decoupling control unit 86 described above with reference to FIG. 4.

[0105] In step S18, feedforward control is performed based on the d-axis and q-axis command voltages Vd and Vq and the d-axis and q-axis input voltages Esd and Esq. In this case, the control device 60 functions as the d-axis and q-axis feedforward control units 87a and 87b described above with reference to FIG.

[0106] In step S19, the U-, V-, and W-phase modulation factors Mu, Mv, and Mw are calculated based on the d- and q-axis command voltages Vd and Vq, the phase information θa, and the power supply voltage VDC. In this case, the control device 60 functions as the fixed coordinate conversion unit 88 and the modulation unit 89 described above with reference to FIG.

[0107] In step S20, the electrical angle θe of the rotor 21 is obtained based on the angle sensor 53. The detected value of the field current sensor 52 is also obtained as the field current If. In step S21, the phase currents Iu, Iv, and Iw are converted into second d-axis and q-axis currents id2 and iq2 based on the electrical angle θe of the rotor 21. In this case, the control device 60 functions as the second coordinate conversion unit 110 described above with reference to FIG. 3 .

[0108] In step S22, the field target current If* is set based on the second d-axis current id2, the d-axis and q-axis inductances Ld and Lq, and the coupling inductance Lmf. In this case, the control device 60 functions as the target current setting unit 120 described above with reference to FIG.

[0109] In step S23, feedback control is performed to set the field current If to the field target current If*. Here, the field command voltage Vf is calculated. In this case, the control device 60 functions as the field current deviation calculation unit 121 and the field current feedback control unit 122 described above in FIG.

[0110] In step S24, the field modulation factor Mf is calculated based on the field command voltage Vf and the power supply voltage VDC. In this case, the control device 60 functions as the division unit 123 described above with reference to FIG.

[0111] In step S25, switching control of the inverter 31 is performed based on the phase modulation factors Mu, Mv, and Mw. In this case, the control device 60 functions as a comparison unit 90 and an inversion unit 91. Furthermore, switching control of the field energization circuit 33 is performed based on the field modulation factor Mf. In this case, the control device 60 functions as a comparison unit 124 and an inversion unit 125. In this embodiment, the processing of steps S16 to S19 and S25 corresponds to the "armature current control unit."

[0112] The processes of steps S13 to S19 and S25 are processes for performing three-phase charging control and correspond to the "first control unit." The processes of steps S20 to S25 are processes for performing torque reduction control and correspond to the "second control unit." The processes of steps S20 to S24 do not necessarily have to be performed after the process of step S19, but may be performed after the process of step S12 and before the process of step S13. Furthermore, the processes of steps S13 to S19 and the process of step S20 may be performed in parallel.

[0113] In the above-described external charging control, three-phase charging control is performed in a state in which the storage battery 10 and the three-phase AC power supply 41 are electrically connected via the respective phase windings 24U, 24V, and 24W and the inverter 31. This charges the storage battery 10. In this case, current flows through the respective phase windings 24U, 24V, and 24W, generating a reluctance torque TR, which can cause various problems.

[0114] Therefore, in this embodiment, torque reduction control is performed so that the torque Trq generated by the rotating electric machine 20 during three-phase charging control is reduced compared to when no current flows through the field winding 22. As a result, the total torque of the magnet torque TM and the reluctance torque TR is reduced compared to when no current flows through the field winding 22. Therefore, it is possible to suppress the generation of torque by the rotating electric machine 20 when the storage battery 10 is being charged. As a result, it is possible to suppress the occurrence of inconveniences caused by the generation of torque by the rotating electric machine 20 when the storage battery 10 is being charged.

[0115] An example of external charging control will be described below with reference to Fig. 12. In Fig. 12, (a) shows the changes in the phase voltages Vu, Vv, and Vw, (b) shows the changes in the phase currents Iu, Iv, and Iw, (c) shows the change in the field current If, and (d) shows the change in the torque Trq generated by the rotary electric machine 20. In Fig. 12(b), the direction in which current flows from the second end to the first end of each of the phase windings 24U, 24V, and 24W is defined as positive, and the direction in which current flows from the first end to the second end of each of the phase windings 24U, 24V, and 24W is defined as negative.

[0116] During external charging control, torque reduction control is performed, and an AC field current If flows through the field winding 22. The field current If is controlled to be a current in opposite phase to the second d-axis current id2. As a result, the magnet torque TM is generated so that the total torque of the reluctance torque TR and the magnet torque TM is reduced compared to when no current flows through the field winding 22. Therefore, the magnitude of the torque Trq generated by the rotary electric machine 20 is prevented from exceeding the torque threshold value Trqth. The torque threshold value Trqth is, for example, the torque at which the drive wheels 12 begin to rotate, and is set to the upper limit of an expected range of torque at which the drive wheels 12 begin to rotate.

[0117] 13 shows a comparative example in which, unlike the present embodiment, power supply to the field winding 22 is interrupted during external charging control. In FIG. 13, (a) shows the change in field current If, and (b) shows the change in torque Trq generated by the rotary electric machine 20.

[0118] In the comparative example, during external charging control, the field current If is constant at 0 because the power supply to the field winding 22 is cut off. In this case, although reluctance torque TR is generated, magnet torque TM is not generated, which raises concerns that the fluctuation range Ta of the torque Trq generated by the rotating electric machine 20 may become larger than the range determined by the torque threshold value Trqth. If the generated torque Trq exceeds the torque threshold value Trqth, the user may feel uncomfortable during external charging control.

[0119] In this regard, in the present embodiment, as described above, torque reduction control is performed during external charging control. This prevents the magnitude of the torque Trq generated by the rotary electric machine 20 from becoming greater than the torque threshold value Trqth. As a result, it is possible to prevent the user from feeling uncomfortable during external charging control.

[0120] Based on phase information θa of the U-phase voltage Vu, the phase currents Iu, Iv, and Iw are converted into first d- and q-axis currents id1 and iq1. In the first dq coordinate system, the d- and q-axis command currents id* and iq* are set so that the direction of the current vector i flowing through each phase winding 24U, 24V, and 24W is aligned with the direction of the voltage vector V determined from the phase voltages Vu, Vv, and Vw. Then, the first d- and q-axis currents id1 and iq1 are controlled to the d- and q-axis command currents id* and iq*.

[0121] 12(a) and 12(b), the above-described current feedback control controls the phase currents Iu, Iv, and Iw so that the phases of the phase currents Iu, Iv, and Iw are aligned with the phase voltages Vu, Vv, and Vw. This allows the power factor determined by the phase voltages Vu, Vv, and Vw and the phase currents Iu, Iv, and Iw to approach 1. This makes it possible to increase the charging efficiency of the storage battery 10 while reducing the torque Trq generated by the rotating electric machine 20 during three-phase charging control.

[0122] Phase information θa of the U-phase voltage Vu is used as periodically varying phase information when performing current feedback control of the first d- and q-axis currents id1 and iq1. As a result, during external charging control, the first d- and q-axis currents id1 and iq1, which are DC currents in the first dq coordinate system, are targeted for control, and current feedback control is performed. This allows for a configuration suitable for performing current feedback control such that the direction of the current vector i flowing through each phase winding 24U, 24V, and 24W in the first dq coordinate system is aligned with the direction of the voltage vector V determined from the phase voltages Vu, Vv, and Vw. As a result, the power factor determined from the phase voltages Vu, Vv, and Vw and the phase currents Iu, Iv, and Iw can be accurately increased.

[0123] Second Embodiment A second embodiment will be described below with reference to the drawings, focusing on differences from the first embodiment. In this embodiment, the configuration of the torque reduction control is changed.

[0124] Fig. 14 shows the waveform of the generated torque Trq when the field current If is generated as shown in equation (eq2) above during torque reduction control. In this case, theoretically, the generated torque Trq of the rotary electric machine 20 is 0, as shown by the dashed line in Fig. 14. However, in reality, as shown by the solid line in Fig. 14, the generated torque Trq may fluctuate, albeit slightly, due to detection errors of the phase current sensor 51, etc. In this case, the polarity of the generated torque Trq alternates between positive and negative.

[0125] As shown in Fig. 15 , backlash is provided in the first gear 13 and the second gear 14 that constitute the power transmission mechanism 11. Fig. 15 illustrates an example of external gears as the gears 13, 14. In a configuration that provides backlash, when the polarity of the torque Trq generated by the rotor 21 alternates between positive and negative, the rotation directions of the first gear 13 and the second gear 14 alternate, which can cause tooth strike, in which the teeth 13 a of the first gear 13 and the teeth 14 a of the second gear 14 collide with each other.

[0126] In external charging control, if the magnitude of the torque Trq generated by the rotor 21 falls below the torque threshold Trqth and the gear rattle noise increases despite the reduction in the torque Trq generated by the rotor 21, the NV (Noise, Vibration) of the system will deteriorate.

[0127] Therefore, in this embodiment, as shown in FIG. 16, the teeth 13a of the first gear 13 and the teeth 14a of the second gear 14 are kept pressed against each other to suppress the occurrence of teeth rattle noise and improve noise reduction.

[0128] The target current setting unit 120 sets the field target current If* so that the time average value of the torque Trq generated by the rotary electric machine 20 in one cycle or multiple cycles of the AC current flowing through the phase windings 24U, 24V, 24W is reduced to a value lower than when no current flows through the field winding 22. In this case, the target current setting unit 120 sets the field target current If* so that the time average value of the torque generated Trq is offset from zero.

[0129] 17 shows an example of a case where the field target current If* is set so as to offset the torque Trq generated by the rotary electric machine 20 to the positive side during torque reduction control. In FIG. 17, the time average value of the torque Trq generated by the rotary electric machine 20 is offset by an offset value Toffset, and the fluctuation width ΔT of the generated torque Trq is kept within a range from 0 to the torque threshold value Trqth. This prevents the polarity of the torque Trq generated by the rotary electric machine 20 from alternating between positive and negative, thereby preventing rattle noise. This allows for improvement in noise immunity.

[0130] Specifically, the target current setting unit 120 shifts the phase of the field target current If* relative to the field current If, which is in phase with or opposite to the second d-axis current id2. The field current deviation calculation unit 121, the field current feedback control unit 122, the division unit 123, the comparison unit 124, and the inversion unit 125 control the field current If to the field target current If*. This makes the magnet torque TM larger or smaller than the reluctance torque TR. Therefore, the time average value of the torque Trq generated by the rotating electric machine 20 can be offset from 0.

[0131] For example, the target current setting unit 120 can set the field target current If* using information (specifically, map information or formula information) that associates the second d-axis current id2 with the field target current If* whose phase is shifted with respect to the second d-axis current id2. Furthermore, for example, when setting the field target current If* using information that associates the input current with the field target current If* whose phase is opposite to that of the input current, the target current setting unit 120 can set the field target current If* using a shift current whose phase is shifted with respect to the second d-axis current id2 as the input current. For example, the shift current can be a current converted from a three-phase fixed coordinate system to a second dq coordinate system based on phase information that is shifted to the positive or negative side with respect to the electrical angle θe of the rotor 21.

[0132] Figure 18 shows an example of torque reduction control. In Figure 18, (a) to (d) correspond to the above-mentioned Figures 10(a) to (d). In Figure 18(d), the dashed line shows the same waveform as the above-mentioned Figure 10(d), and the solid line shows the waveform when the phase of the field current If is shifted. Here, the phase of the field current If is shifted by a predetermined shift amount Ts.

[0133] The phase shift amount Ts of the field current If is expressed in the range of 0°≦Ts≦360°, where 360° is the value when the phase shift amount Ts of the field current If is shifted by the period T of the field current If relative to the field current If that is in opposite phase to the second d-axis current id2. In this case, the greater the phase shift amount Ts of the field current If is in the range of 0°<Ts≦180°, the greater the offset value Toffset and the greater the fluctuation range ΔT of the torque Trq generated by the rotating electric machine 20. If the fluctuation range ΔT of the torque Trq generated by the rotating electric machine 20 is large, the torque Trq generated by the rotor 21 may exceed the torque threshold value Trqth or fall below 0.

[0134] The phase shift amount Ts of the field current If is determined in accordance with the characteristics of the rotating electric machine 20 (for example, the inductance and electrical resistance of the rotating electric machine 20) so that the generated torque Trq of the rotor 21 falls within a range from 0 to a torque threshold value Trqth. For example, the phase shift amount Ts of the field current If is determined in the range of 0°<Ts≦30°, 0°<Ts≦60°, or 0°<Ts≦90°. In this embodiment, the processing of steps S23 to S25 corresponds to a "field current control unit."

[0135] According to this embodiment, the phase shift amount Ts of the field current If is determined in accordance with the characteristics of the rotary electric machine 20, and therefore, when the time average value of the generated torque Trq of the rotor 21 is offset from 0, the generated torque Trq can be prevented from exceeding the torque threshold value Trqth or falling below 0. Therefore, a configuration suitable for improving NV can be realized. <Other Embodiments> The above-described embodiments may be modified and implemented as follows.

[0136] 19 , the system may include a motor-side switch 45 (corresponding to a “changeover switch”). The motor-side switch 45 is provided on the rotating electric machine 20 side of the filter 43 in the U-, V-, and W-phase charging paths 25U, 25V, and 25W. For example, each motor-side switch 45 is a mechanical relay or a semiconductor switching element.

[0137] The control device 60 controls each motor-side switch 45. When performing external charging control, the control device 60 turns on each main switch 40p, 40n, the input switch 42, and the motor-side switch 45, and turns off each neutral point switch 44a, 44b. On the other hand, when not performing external charging control or when driving the rotating electric machine 20 to rotate, the control device 60 turns on each main switch 40p, 40n and each neutral point switch 44a, 44b, and turns off the input switch 42 and the motor-side switch 45.

[0138] In this embodiment, when the rotating electric machine 20 is driven to rotate, the neutral point switches 44a, 44b are turned on and the motor-side switches 45 are turned off. In this case, while the rotating electric machine 20 is driven to rotate, it is possible to prevent current from flowing between the phase windings 24U, 24V, 24W via the filter 43. Therefore, in a configuration in which the rotating electric machine 20 is used as part of a charger that charges the storage battery 10, it is possible to prevent unintended current from flowing in the system.

[0139] The input switch 42 does not have to be provided on each of the phase charging paths 25U, 25V, 25W. Furthermore, the high-potential-side main switch 40p does not have to be provided on the high-potential-side electrical path Lp, and the low-potential-side main switch 40n does not have to be provided on the low-potential-side electrical path Ln.

[0140] 20 , the system may include a DC-DC converter 130. The DC-DC converter 130 transfers power between the storage battery 10 and the power converter 30. In this embodiment, the DC-DC converter 130 is an isolated DC-DC converter.

[0141] The DC-DC converter 130 is of a DAB (Dual Active Bridge) type and includes a first full-bridge circuit 131, a second full-bridge circuit 133, and a transformer 132 that transmits power between the full-bridge circuits 131 and 133. The transformer 132 includes a first coil 132A connected to the first full-bridge circuit 131, a second coil 132B connected to the second full-bridge circuit 133, and a core 132C that magnetically couples the coils 132A and 132B. The DC-DC converter 130 may be of another type (for example, an LLC type).

[0142] Each full-bridge circuit 131, 133 is configured with upper and lower arm switches. The switches of each full-bridge circuit 131, 133 are semiconductor switching elements, specifically N-channel MOSFETs. The switches of each full-bridge circuit 131, 133 are controlled by the control device 60.

[0143] The command current setting unit 80 may set the d-axis command current id* to a value other than 0 in order to align the direction of the current flowing through each of the phase windings 24U, 24V, 24W with the q-axis direction in the first dq coordinate system. For example, the command current setting unit 80 can set the d-axis command current id* and the q-axis command current iq* to values ​​corresponding to the power supply voltage VDC within a range in which the power factor determined by the current flowing through each of the phase windings 24U, 24V, 24W and the phase voltages Vu, Vv, Vw is equal to or greater than a predetermined value (for example, a value close to 1).

[0144] The first coordinate transformation unit 100 can transform the three-phase fixed coordinate system into the first dq coordinate system based on the phase information θa so that the direction of the voltage vector V determined from the phase voltages Vu, Vv, and Vw faces a direction other than the q-axis direction in the first dq coordinate system. In this case, the command current setting unit 80 sets the d-axis command current id* and the q-axis command current iq* so that the directions of the first d- and q-axis currents id1 and iq1 are aligned with the direction of the voltage vector facing a direction other than the q-axis direction in the first dq coordinate system.

[0145] The first coordinate conversion unit 100 can convert the current and voltage used in three-phase charging control into the current and voltage in the first dq coordinate system based on the V-phase voltage Vv or the W-phase voltage Vw instead of the U-phase voltage Vu.

[0146] Taking the V-phase voltage Vv as an example, the V-phase voltage Vv is input to the first phase acquisition unit 101. The V-phase voltage Vv is an input voltage input from the three-phase AC power supply 41 to the V-phase winding 24V. The first phase acquisition unit 101 can use the detection value of the phase voltage sensor 54 as the V-phase voltage Vv. The first phase acquisition unit 101 acquires phase information of the V-phase voltage Vv. The phase information of the V-phase voltage Vv is similar to the phase information θa of the U-phase voltage Vu. The phase information of the V-phase voltage Vv is input to the first current conversion unit 102 and the voltage conversion unit 103.

[0147] The first current converter 102 can convert the U-, V-, and W-phase currents Iu, Iv, and Iw into a first d-axis current id1 and a first q-axis current iq1 based on phase information of the V-phase voltage Vv. The voltage converter 103 can convert the U-, V-, and W-phase voltages Vu, Vv, and Vw into d- and q-axis input voltages Esd and Esq based on phase information of the V-phase voltage Vv.

[0148] In the first embodiment, the target current setting unit 120 may set, as the field target current If*, a current other than a current having an opposite phase to the second d-axis current id2, within a range in which the total torque of the magnet torque TM and the reluctance torque TR is reduced. For example, the target current setting unit 120 may set the field target current If* so that the phase difference θs between the field current If and the second d-axis current id2 is 90°<θs<270°, 150°≦θs≦210°, or 170°≦θs≦190°.

[0149] The rotating electric machine 20 may be a rotating electric machine having reverse saliency (Lq - Ld > 0), in which the q-axis inductance Lq is greater than the d-axis inductance Ld. In this case, the target current setting unit 120 sets a current in phase with the second d-axis current id2 as the field target current If*. This allows the characteristics of the rotating electric machine 20 to be taken into consideration, and allows the field current If to flow so that the magnet torque TM is generated in the direction opposite to the direction in which the reluctance torque TR is generated. Therefore, during torque reduction control, the magnet torque TM can be accurately generated so that the total torque of the reluctance torque TR and the magnet torque TM is reduced compared to when no current is flowing through the field winding 22.

[0150] The target current setting unit 120 can set the field target current If* to a current other than the current in phase with the second d-axis current id2, as in the case where the rotating electric machine 20 has forward salient polarity. For example, the target current setting unit 120 can set the field target current If* so that −90°<θs<90°, −30°≦θs≦30°, or −10°≦θs≦10° within a range in which the total torque of the magnet torque TM and the reluctance torque TR is reduced. Furthermore, for example, the target current setting unit 120 can set the field target current If* so that the phase of the field target current If* is shifted by a shift amount Ts with respect to the field current If that is in phase with the second d-axis current id2, in order to offset the time average value of the torque Trq generated by the rotating electric machine 20 from 0.

[0151] In the torque reduction control of the second embodiment, the polarity of the generated torque Trq of the rotary electric machine 20 may be negative during a portion of one cycle, or may be negative during a portion of a plurality of cycles. Even in this case, the time average value of the generated torque Trq over a plurality of cycles of the AC current flowing through the phase windings 24U, 24V, 24W is offset from 0, thereby making it possible to reduce the gear rattle noise and the frequency of gear rattles even if they occur.

[0152] The switches constituting the power converter 30 and each of the full-bridge circuits 131 and 133 are not limited to N-channel MOSFETs, but may be, for example, IGBTs (Insulated Gate Bipolar Transistors). In this case, it is sufficient that a freewheel diode is connected in anti-parallel to the IGBT.

[0153] The power storage unit connected to a power converter such as an inverter is not limited to a storage battery. For example, it may be a large-capacity electric double layer capacitor, or may be a unit including both a storage battery and an electric double layer capacitor.

[0154] The mobile body on which the control device 60 is mounted is not limited to a vehicle, but may be, for example, an aircraft or a ship. In the case of an aircraft, the rotationally driven object is, for example, a propeller, and in the case of a ship, the rotationally driven object is, for example, a screw. Furthermore, the device on which the control device is mounted is not limited to a mobile body, but may also be a stationary device.

[0155] The control device and method described herein may be implemented by a special-purpose computer configured with a processor and memory programmed to execute one or more functions embodied in a computer program. Alternatively, the control device and method described herein may be implemented by a special-purpose computer configured with a processor comprising one or more dedicated hardware logic circuits. Alternatively, the control device and method described herein may be implemented by one or more special-purpose computers configured with a combination of a processor and memory programmed to execute one or more functions and a processor configured with one or more hardware logic circuits. Furthermore, the computer program may be stored in a computer-readable non-transitory tangible recording medium as instructions to be executed by a computer.

[0156] The following describes characteristic configurations extracted from the above-described embodiments. a power converter control device (60) applicable to a system including: a rotating electric machine (20) having an armature winding (24U, 24V, 24W) and a field winding (22); an energy storage unit (10) that stores drive power for the rotating electric machine; a first power converter (31) electrically connected to the armature winding and controlling a current flowing through the armature winding; and a second power converter (33) electrically connected to the field winding and controlling a current flowing through the field winding, the power converter control device comprising: a first control unit that performs switching control of the first power converter so that, in a state in which an AC power source (41) is electrically connected to the energy storage unit via the armature winding and the first power converter, a current flows from the AC power source to the energy storage unit; and a second control unit that performs switching control of the second power converter so that torque of the rotating electric machine generated during switching control of the first power converter is reduced compared to when no current flows through the field winding. [Configuration 2] The power converter control device according to Configuration 1, wherein the rotating electric machine has a characteristic that a d-axis inductance is larger than a q-axis inductance, and the second control unit performs switching control of the second power converter so that a current that is in phase with a d-axis component of the current flowing through the armature winding flows through the field winding. [Configuration 3] The power converter control device according to Configuration 1, wherein the rotating electric machine has a characteristic that a q-axis inductance is larger than a d-axis inductance, and the second control unit performs switching control of the second power converter so that a current that is in phase with a d-axis component of the current flowing through the armature winding flows through the field winding. [Configuration 4] The power converter control device according to any one of Configurations 1 to 3, wherein the first control unit performs switching control of the first power converter so that the phase of the current flowing through the armature winding is aligned with the phase of the input voltage input from the AC power source to the armature winding.[Configuration 5] The control device for a power converter according to Configuration 4, wherein the first control unit includes: a coordinate conversion unit that converts the current flowing in the armature winding into a current in a dq coordinate system based on phase information of the input voltage; a command current setting unit that sets a command current for the armature winding so that the direction of the current flowing in the armature winding aligns with the direction of a voltage vector determined from the input voltage in the dq coordinate system; and an armature current control unit that performs switching control of the first power converter so as to control the current flowing in the armature winding to the command current. [Configuration 6] The control device for a power converter according to any one of configurations 1 to 5, wherein the system constitutes a power transmission mechanism (11) from a rotor (21) of the rotating electric machine to a rotationally driven object (12), and includes at least a pair of gears (13, 14) that rotate by rotational power from the rotor and mesh with each other, and the second control unit performs switching control of the second power converter so as to reduce the torque of the rotating electric machine generated during switching control of the first power converter compared to when no current flows through the field winding, and to offset from zero a time average value of the torque of the rotating electric machine over one period or multiple periods of the AC current flowing through the armature winding. [Configuration 7] The control device for a power converter according to Configuration 6, wherein the second control unit has: a target current setting unit that sets a field target current; and a field current control unit that controls the field current flowing in the field winding to the field target current, and the target current setting unit offsets the time average value from 0 by shifting the phase of the field target current with respect to the field current that is in phase with or opposite to a d-axis component of the current flowing in the armature winding. [Configuration 8] The control device for a power converter according to any one of Configurations 1 to 7, wherein the armature winding is a multi-phase winding having first ends connected to the first power converter and second ends connected to each other at neutral points, and further comprising neutral point switches (44a, 44b) provided on the neutral point side of each armature winding and electrically connecting or disconnecting each armature winding. [Configuration 9] The control device for a power converter according to any one of Configurations 1 to 8, further comprising a changeover switch (42, 45) provided between the armature winding and the AC power source, for switching between conduction and interruption of a current flowing through the armature winding.

[0157] Although the present disclosure has been described with reference to the embodiments, it is understood that the present disclosure is not limited to the embodiments or structures. The present disclosure also encompasses various modifications and equivalent modifications. In addition, various combinations and forms, including only one element, more than one element, or less than one element, are also within the scope and spirit of the present disclosure.

Claims

1. A power converter control device (60) applied to a system including: a rotating electric machine (20) having an armature winding (24U, 24V, 24W) and a field winding (22); a power storage unit (10) that stores drive power for the rotating electric machine; a first power converter (31) electrically connected to the armature winding and controlling a current flowing through the armature winding; and a second power converter (33) electrically connected to the field winding and controlling the current flowing through the field winding. The power converter control device (60) includes: a first control unit that performs switching control of the first power converter so that a current flows from an AC power source (41) to the power storage unit in a state where the AC power source is electrically connected to the power storage unit via the armature winding and the first power converter; and a second control unit that performs switching control of the second power converter so that the torque of the rotating electric machine generated during switching control of the first power converter is reduced compared to a case in which no current flows through the field winding.

2. A control device for a power converter as described in claim 1, wherein the rotating electric machine has a characteristic in which the d-axis inductance is larger than the q-axis inductance, and the second control unit performs switching control of the second power converter so that a current that is in opposite phase to the d-axis component of the current flowing in the armature winding flows in the field winding.

3. A control device for a power converter as described in claim 1, wherein the rotating electric machine has a characteristic in which the q-axis inductance is larger than the d-axis inductance, and the second control unit performs switching control of the second power converter so that a current that is in phase with the d-axis component of the current flowing in the armature winding flows in the field winding.

4. A power converter control device as claimed in any one of claims 1 to 3, wherein the first control unit performs switching control of the first power converter so as to align the phase of the current flowing through the armature winding with the phase of the input voltage input from the AC power source to the armature winding.

5. The control device for a power converter as described in claim 4, wherein the first control unit comprises: a coordinate conversion unit that converts the current flowing in the armature winding into a current in a dq coordinate system based on phase information of the input voltage; a command current setting unit that sets a command current for the armature winding so that the direction of the current flowing in the armature winding in the dq coordinate system is aligned with the direction of a voltage vector determined from the input voltage; and an armature current control unit that performs switching control of the first power converter so as to control the current flowing in the armature winding to the command current.

6. A control device for a power converter as described in any one of claims 1 to 3, wherein the system constitutes a power transmission mechanism (11) from a rotor (21) of the rotating electric machine to a rotationally driven object (12), and comprises at least a pair of gears (13, 14) that rotate by rotational power from the rotor and mesh with each other, and the second control unit performs switching control of the second power converter so as to reduce the torque of the rotating electric machine generated during switching control of the first power converter compared to a case in which no current flows through the field winding, and to offset from zero the time average value of the torque of the rotating electric machine during one period or multiple periods of the AC current flowing through the armature winding.

7. A control device for a power converter as described in claim 6, wherein the second control unit has: a target current setting unit which sets a field target current; and a field current control unit which controls the field current flowing through the field winding to the field target current, and the target current setting unit offsets the time average value from 0 by shifting the phase of the field target current with respect to the field current which is in phase with or opposite to the d-axis component of the current flowing through the armature winding.

8. A power converter control device as claimed in any one of claims 1 to 3, wherein the armature windings are multi-phase windings having first ends connected to the first power converter and second ends connected to each other at a neutral point, and further comprising neutral point switches (44a, 44b) provided on the neutral point side of each of the armature windings for electrically connecting or disconnecting each of the armature windings.

9. A control device for a power converter as claimed in any one of claims 1 to 3, further comprising a changeover switch (42, 45) provided between the armature winding and the AC power source for switching between conduction and interruption of a current flowing through the armature winding.

10. A program applied to a system including a rotating electric machine (20) having an armature winding (24U, 24V, 24W) and a field winding (22), an energy storage unit (10) that stores drive power for the rotating electric machine, a first power converter (31) electrically connected to the armature winding and controlling a current flowing through the armature winding, a second power converter (33) electrically connected to the field winding and controlling a current flowing through the field winding, and a computer (60a), comprising: a first control process for performing switching control of the first power converter so that a current flows from an AC power source (41) to the energy storage unit in a state in which the AC power source is electrically connected to the energy storage unit via the armature winding and the first power converter; and a second control process for performing switching control of the second power converter so that a torque of the rotating electric machine generated during switching control of the first power converter is reduced compared to a case in which no current flows through the field winding. A program for causing the computer to execute the above.

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