Control device for rotary electric machine, program, and control method for rotary electric machine

Abstract

A control device (60) is applied in a system comprising a rotary electric machine (40), a first inverter (20), a second inverter (30), a positive electrode-side bus bar (11), and a negative electrode-side bus bar (12). In each phase, a first upper arm switch (SUHa, SVHa, SWHa) and a first lower arm switch (SULa, SVLa, SWLa) are electrically connected to a first end of a winding (51U, 51V, 51W). In each phase, a second upper arm switch (SUHb, SVHb, SWHb) and a second lower arm switch (SULb, SVLb, SWLb) are electrically connected to a second end of the winding. The control device comprises: voltage calculation units (61, 63, 64) that calculate a voltage command value for each phase; a current calculation unit (65) that calculates a zero-phase current that is the total of the respective phase currents flowing through the windings of the phases; and a correction unit (66) that, on the basis of the calculated zero-phase current, corrects the voltage command value of each phase so as to reduce the zero-phase current.

Description

Rotating electric machine control device, program, and rotating electric machine control method CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is based on Japanese Application No. 2023-213788 filed on December 19, 2023, the contents of which are incorporated herein by reference.

[0002] The present disclosure relates to a control device for a rotating electric machine, a program, and a control method for a rotating electric machine.

[0003] Conventionally, a system for controlling a rotating electric machine using two inverters has been known. In this system, a first inverter is electrically connected to a first end of a multi-phase winding of the rotating electric machine, and a second inverter is electrically connected to a second end of the winding. The first inverter and the second inverter share a DC bus. By driving the rotating electric machine with the first inverter and the second inverter, high output and high efficiency of the system can be achieved. An example of such a technology is disclosed in Patent Document 1.

[0004] JP 2017-169251 A

[0005] In the above-described system, a technique is desired to suppress the occurrence of zero-phase current, which is the sum of the currents flowing through the windings of each phase.

[0006] The present disclosure has been made in view of the above, and an object of the present disclosure is to provide a control device for a rotating electric machine, a program, and a control method for a rotating electric machine that can suppress the occurrence of zero-phase current.

[0007] The present disclosure relates to a control device for a rotating electric machine that is applied to a system including: a rotating electric machine having a multi-phase winding; a first inverter having first upper arm switches and first lower arm switches connected in series for the same number of phases; a second inverter having second upper arm switches and second lower arm switches connected in series for the same number of phases; a positive bus bar that electrically connects, in each phase, a high potential side terminal of the first upper arm switch and a high potential side terminal of the second upper arm switch; and a negative bus bar that electrically connects, in each phase, a low potential side terminal of the first lower arm switch and a low potential side terminal of the second lower arm switch, and that performs switching control of the first inverter and the second inverter, wherein, in each phase, the first upper arm switch and the first lower arm switch are electrically connected to a first end of both ends of the winding, and the second upper arm switch and the second lower arm switch are electrically connected to a second end of both ends of the winding, a voltage calculation unit that calculates a voltage command value for each phase to control a control variable of the rotating electric machine to a required value; The inverter includes a current calculation unit that calculates a zero-phase current, which is the sum of phase currents flowing through the windings of each phase; and a correction unit that corrects the voltage command value of each phase based on the calculated zero-phase current so as to reduce the zero-phase current.

[0008] According to the present disclosure, the voltage command value of each phase is corrected based on the calculated zero-phase current so as to reduce the zero-phase current. In this case, when the zero-phase current is flowing, it is possible to adjust the voltage applied to the winding of each phase so as to reduce the magnitude of the zero-phase current to be calculated in the future. As a result, the occurrence of the zero-phase current can be suppressed.

[0009] 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 a control system according to a first embodiment, Fig. 2 is a functional block diagram of switching control performed by a control device, Fig. 3 is a functional block diagram of switching control performed by a control device according to a second embodiment, Fig. 4 is a diagram showing an example of a method for setting a proportional gain, Fig. 5 is a diagram showing an example of a method for setting a proportional gain, Fig. 6 is a functional block diagram of switching control performed by a control device according to a third embodiment, Fig. 7 is a functional block diagram of switching control performed by a control device according to a fourth embodiment, Fig. 8 is a functional block diagram of switching control performed by a control device according to a modification of the fourth embodiment, Fig. 9 is a functional block diagram of switching control performed by a control device according to another embodiment, and Fig. 10 is a diagram showing an example of a method for setting a differential gain.

[0010] Several embodiments will be described with reference to the drawings. In several embodiments, functionally and / or structurally corresponding and / or associated parts may be designated by the same reference numerals or reference numerals that differ in the hundredth or more digit. For corresponding and / or associated parts, reference may be made to the descriptions of other embodiments.

[0011] A first embodiment of a control device for a rotating electric machine according to the present disclosure will now be described with reference to the drawings. The control device for a rotating electric machine according to the present embodiment is mounted on an electrically powered vehicle such as an electric vehicle or a hybrid vehicle, and is used in an on-board control system.

[0012] As shown in Fig. 1, the control system 100 includes a battery 10, a first inverter 20, a second inverter 30, and a rotating electrical machine 40. The 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.

[0013] The first inverter 20 and the second inverter 30 are power conversion circuits that convert DC power supplied from the battery 10 into three-phase AC power and supply it to the rotating electric machine 40 .

[0014] The first inverter 20 includes a series connection of U-, V-, and W-phase first upper arm switches SUHa, SVHa, and SWHa and U-, V-, and W-phase first lower arm switches SULa, SVLa, and SWLa. The second inverter 30 includes a series connection of U-, V-, and W-phase second upper arm switches SUHb, SVHb, and SWHb and U-, V-, and W-phase second lower arm switches SULb, SVLb, and SWLb.

[0015] In this embodiment, voltage-controlled semiconductor switching elements, more specifically, IGBTs, are used as the switches SUHa to SWLa and SUHb to SWLb. In this embodiment, the high-potential terminal of each switch is the collector, and the low-potential terminal is the emitter. Freewheeling diodes DUHa, DVHa, DWHa, DULa, DVLa, DWLa, DUHb, DVHb, DWHb, DULb, DVLb, and DWLb are connected in anti-parallel to the switches SUHa, SVHa, SWHa, SULa, SVLa, SWLa, SUHb, SVHb, SWHb, SULb, SVLb, and SWLb, respectively.

[0016] The collectors of the first upper arm switches SUHa, SVHa, SWHa of each phase and the collectors of the second upper arm switches SUHb, SVHb, SWHb of each phase are electrically connected by a positive bus 11 such as a bus bar. The emitters of the first lower arm switches SULa, SVLa, SWLa of each phase and the emitters of the second lower arm switches SULb, SVLb, SWLb of each phase are electrically connected by a negative bus 12 such as a bus bar.

[0017] The positive terminal of the battery 10 is electrically connected to the positive bus 11, and the negative terminal of the battery 10 is electrically connected to the negative bus 12. The battery 10 is electrically connected to the buses 11, 12 on the opposite side of the first inverter 20 from the second inverter 30.

[0018] The rotating electric machine 40 is an on-vehicle main motor. A rotor 41 of the rotating electric machine 40 is capable of transmitting power to drive wheels (not shown) of the vehicle. In this embodiment, the rotating electric machine 40 is a permanent magnet field type synchronous machine. The rotor 41 includes permanent magnets 42 (e.g., neodymium magnets) as field poles.

[0019] The rotating electric machine 40 includes a stator 50. The stator 50 includes armature windings, namely, a U-phase winding 51U, a V-phase winding 51V, and a W-phase winding 51W. The phase windings 51U, 51V, and 51W are arranged with an electrical angle of 120°. The phase windings 51U, 51V, and 51W are open-connected, and both ends of each phase winding 51U, 51V, and 51W are electrically connected to the first inverter 20 or the second inverter 30.

[0020] Specifically, in each phase, first ends 51Ua, 51Va, 51Wa of the windings 51U, 51V, 51W are electrically connected to first upper switches SUHa, SVHa, SWHa and first lower switches SULa, SVLa, SWLa of the corresponding phase. Also, second ends 51Ub, 51Vb, 51Wb of the windings 51U, 51V, 51W are electrically connected to second upper switches SUHb, SVHb, SWHb and second lower switches SULb, SVLb, SWLb of the corresponding phase.

[0021] The control system 100 includes a changeover switch 13. The changeover switch 13 is provided on the positive bus 11 between the first inverter 20 and the second inverter 30. When the changeover switch 13 is turned on, it electrically connects the first inverter 20 and the second inverter 30, and when turned off, it electrically disconnects the first inverter 20 and the second inverter 30. The changeover switch 13 is controlled by a control device 60 included in the control system 100. The changeover switch 13 is provided to switch the driving state of the control system 100, as will be described later.

[0022] For example, the changeover switch 13 is a semiconductor switching element such as an IGBT or a relay. When an IGBT is used as the changeover switch 13, a freewheel diode is connected in parallel to the changeover switch 13. In this case, the anode of the freewheel diode is electrically connected to the second inverter 30 side, and the cathode is electrically connected to the first inverter 20 side.

[0023] The control system 100 includes a power switch 14 and a capacitor 15. The power switch 14 is, for example, a semiconductor switching element or a relay. The power switch 14 is provided on the positive bus 11 between the positive terminal of the battery 10 and the first inverter 20. When the power switch 14 is turned on, it electrically connects the battery 10 and the rotating electric machine 40, and when it is turned off, it electrically disconnects the battery 10 and the rotating electric machine 40. The power switch 14 is driven by the control device 60.

[0024] A first end of the capacitor 15 is electrically connected to the positive bus 11 between the power switch 14 and the first inverter 20. A second end of the capacitor 15 is electrically connected to the negative bus 12 between the negative terminal of the battery 10 and the first inverter 20.

[0025] The control system 100 includes a current sensor 16 and a rotation angle sensor 17. The current sensor 16 detects phase currents Iu, Iv, and Iw flowing through the respective phase windings 51U, 51V, and 51W. In this embodiment, the current sensor 16 is provided at one of the ends of each phase winding 51U, 51V, and 51W closer to the first inverter 20. The sign of the detected value of the current sensor 16 is positive when the current flows from the first terminal 51Ua, 51Va, and 51Wa of each phase winding 51U, 51V, and 51W to the second terminal 51Ub, 51Vb, and 51Wb, and negative when the current flows from the second terminal 51Ub, 51Vb, and 51Wb to the first terminal 51Ua, 51Va, and 51Wa. Note that the current sensor 16 may also be provided at one of the ends of each phase winding 51U, 51V, and 51W closer to the second inverter 30.

[0026] The rotation angle sensor 17 is, for example, a resolver, and detects the electrical angle θ of the rotor 41. The phase currents Iur, Ivr, and Iwr detected by the current sensor 16 and the electrical angle θr detected by the rotation angle sensor 17 are input to the control device 60.

[0027] The control device 60 is primarily composed of a microcomputer equipped with a CPU and various memories. The functions provided by the microcomputer can be provided by software recorded in a physical memory device and a computer executing the software, software alone, hardware alone, or a combination thereof. For example, when the microcomputer is provided by hardware electronic circuits, the functions can be provided by digital circuits including numerous logic circuits or analog circuits. For example, the microcomputer executes programs stored on a non-transitory tangible storage medium serving as its own storage unit. The programs include, for example, programs that realize the functions shown in Figures 2 to 10. Execution of the programs results in the execution of methods corresponding to the programs. The storage unit is, for example, non-volatile memory. The programs stored in the storage unit can be downloaded and updated via a communication network such as the Internet, for example, via OTA (Over the Air).

[0028] The control device 60 controls the selector switch 13 to switch the drive state of the control system 100 between a Y drive state and an H drive state. The control device 60 turns off the selector switch 13, turns on the second upper arm switches SUHb, SVHb, and SWHb for each phase, and turns off the second lower arm switches SULb, SVLb, and SWLb for each phase, thereby placing the control system 100 in the Y drive state. In the Y drive state, the phase windings 51U, 51V, and 51W are Y-connected via the second inverter 30. On the other hand, the control device 60 turns on the selector switch 13 to place the control system 100 in the H drive state.

[0029] In the Y drive state, the control device 60 controls the switching of the switches SUHa to SWLa in the first inverter 20. In addition, in the H drive state, the control device 60 controls the switching of both the switches SUHa to SWLa in the first inverter 20 and the switches SUHb to SWLb in the second inverter 30. By appropriately switching between the Y drive state and the H drive state and executing switching control, the control system 100 can be made to have a high output and high efficiency.

[0030] When the control system 100 is in the H drive state and switching control is performed, a current flows between the first inverter 20 and the second inverter 30 via the positive bus 11 and the negative bus 12. In this case, a zero-phase current I0, which is the sum of the currents flowing through the phase windings 51U, 51V, and 51W, may be generated in the control system 100. The zero-phase current I0 is one of the factors that cause malfunctions in the control system 100. Therefore, a technology for suppressing the generation of the zero-phase current I0 is desired.

[0031] A configuration for suppressing the occurrence of zero-phase current will be described below.

[0032] 2, the control device 60 includes a setting unit 61. A torque request value Trq* is input to the setting unit 61 from a control device that is higher in level than the control device 60. The setting unit 61 calculates a d-axis current command value Id* and a q-axis current command value Iq* in a dq coordinate system based on the input torque request value Trq*.

[0033] The control device 60 includes a dq converter 62. The dq converter 62 receives the phase currents Iur, Ivr, and Iwr detected by the current sensor 16 and the electrical angle θr detected by the rotation angle sensor 17. The dq converter 62 calculates a d-axis current value Idr and a q-axis current value Iqr based on the detected phase currents Iur, Ivr, and Iwr and the electrical angle θr.

[0034] The control device 60 includes a current feedback unit 63. The current feedback unit 63 receives d-axis and q-axis current command values ​​Id* and Iq* and d-axis and q-axis current values ​​Idr and Iqr. The current feedback unit 63 calculates a d-axis current deviation, which is the difference between the d-axis current command value Id* and the d-axis current value Idr, and calculates a d-axis voltage command value Vd* as a manipulated variable for feedback-controlling the calculated d-axis current deviation to zero. The current feedback unit 63 also calculates a q-axis current deviation, which is the difference between the q-axis current command value Iq* and the q-axis current value Iqr, and calculates a q-axis voltage command value Vq* as a manipulated variable for feedback-controlling the calculated q-axis current deviation to zero. The feedback control may be, for example, proportional-plus-integral control.

[0035] The control device 60 includes a UVW converter 64. The d- and q-axis voltage command values ​​Vd* and Vq* and the detected electrical angle θr are input to the UVW converter 64. The UVW converter 64 calculates U-, V-, and W-phase voltage command values ​​Vu*, Vv*, and Vw* based on the input d- and q-axis voltage command values ​​Vd* and Vq* and the electrical angle θr. The phase voltage command values ​​Vu*, Vv*, and Vw* are command values ​​for the phase voltages Vu, Vv, and Vw, respectively. In this embodiment, the signs of the phase voltages Vu, Vv, Vw are positive when the potential at the first terminals 51Ua, 51Va, 51Wa of the windings 51U, 51V, 51W is higher than the potential at the second terminals 51Ub, 51Vb, 51Wb of the windings 51U, 51V, 51W, and negative when the potential at the second terminals 51Ub, 51Vb, 51Wb of the windings 51U, 51V, 51W is higher than the potential at the first terminals 51Ua, 51Va, 51Wa of the windings 51U, 51V, 51W. The setting unit 61, current feedback unit 63, and UVW conversion unit 64 correspond to a "voltage calculation unit."

[0036] The control device 60 includes a current calculation unit 65 and a correction unit 66. The current calculation unit 65 calculates the zero-phase current Ior by summing the detected phase currents Iur, Ivr, and Iwr. FIG. 2 shows a first adder 65a and a second adder 65b as an example of the current calculation unit 65. The first adder 65a adds the detected W-phase current Iwr to the detected V-phase current Ivr. The second adder 65b adds the detected U-phase current Iur to the sum of the V- and W-phase currents Ivr and Iwr calculated by the first adder 65a. In this case, the output value of the second adder 65b is the zero-phase current Ior.

[0037] The zero-phase current I0r calculated by the current calculation unit 65 is input to the correction unit 66. Based on the calculated zero-phase current I0r, the correction unit 66 corrects the phase voltage command values ​​Vu*, Vv*, and Vw* so as to reduce the zero-phase current I0. In other words, based on the calculated zero-phase current I0r, the correction unit 66 feedback-controls the zero-phase current I0 to the command value (0 in this case).

[0038] More specifically, the correction unit 66 includes a state feedback unit 67 and U-, V-, and W-phase calculation units 68U, 68V, and 68V. The state feedback unit 67 multiplies the calculated zero-phase current Ior by a proportional gain Kp (corresponding to a "correction coefficient") to calculate a feedback correction amount Vcr (i.e., Kp·Ior) of each phase voltage command value Vu*, Vv*, and Vw*. For example, the proportional gain Kp is a predetermined positive constant.

[0039] The U-phase calculation unit 68U subtracts the feedback correction amount Vcr from the U-phase voltage command value Vu*. The V-phase calculation unit 68V subtracts the feedback correction amount Vcr from the V-phase voltage command value Vv*. The W-phase calculation unit 68W subtracts the feedback correction amount Vcr from the W-phase voltage command value Vw*. In this case, for example, when the phase currents Iu, Iv, and Iw flow in the positive direction, the phase voltage command values ​​Vu*, Vv*, and Vw* are corrected so that the magnitudes of the positive phase voltages Vu, Vv, and Vw are reduced. On the other hand, when the phase currents Iu, Iv, and Iw flow in the negative direction, the phase voltage command values ​​Vu*, Vv*, and Vw* are corrected so that the magnitudes of the negative phase voltages Vu, Vv, and Vw are reduced.

[0040] The control device 60 includes a modulator 69. The modulator 69 receives corrected phase voltage command values ​​Vu*, Vv*, and Vw*, which are output values ​​from the phase calculation units 68U, 68V, and 68W. The modulator 69 generates operation signals SUHa to SWLa of the first inverter 20 and operation signals SUHb to SWLb of the second inverter 30 based on the corrected phase voltage command values ​​Vu*, Vv*, and Vw* and a carrier signal. The carrier signal is, for example, a triangular wave signal. Switching control of the first inverter 20 and the second inverter 30 is performed based on the generated operation signals.

[0041] According to this embodiment, the phase voltage command values ​​Vu*, Vv*, and Vw* are corrected based on the calculated zero-phase current Ior so as to reduce the zero-phase current I0. In this case, while the zero-phase current I0 is flowing, it is possible to adjust the phase voltages Vu, Vv, and Vw applied to the phase windings 51U, 51V, and 51W so as to reduce the magnitude of the zero-phase current Ior to be calculated in the future. As a result, the generation of the zero-phase current I0 can be suppressed.

[0042] The calculated zero-phase current I0r is multiplied by a proportional gain Kp to calculate a feedback correction amount Vcr, thereby enabling proportional control to feedback control the zero-phase current I0 to zero with a simple configuration.

[0043] In the feedback control for suppressing the occurrence of the AC zero-phase current I0, if integral control is performed, even if the zero-phase current I0 is reduced to zero or close to zero, the integral value of the zero-phase current I0r calculated up to that point may have an effect, and the phase voltage command values ​​Vu*, Vv*, and Vw* may be overcorrected. In this case, a situation may arise in which the occurrence of the zero-phase current I0 cannot be appropriately suppressed. Therefore, in this embodiment, of the proportional control and integral control for feedback control of the zero-phase current I0 to zero, only proportional control is performed. This makes it possible to realize a configuration suitable for suppressing the occurrence of the zero-phase current I0. Furthermore, because integral control is not performed, the processing load on the control device 60 can be reduced.

[0044] A permanent magnet field type synchronous machine is used as the rotating electric machine 40. In this case, there is a concern that the influence of the zero-phase current I0 will be significant depending on the structure of the rotating electric machine 40, such as the magnetic circuit between the stator 50 and the rotor 41 and the winding method of each phase winding 51U, 51V, 51W. Therefore, there is a great advantage in applying the configuration for suppressing the generation of the zero-phase current I0 according to this embodiment to the rotating electric machine 40, which is a synchronous machine.

[0045] 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 method for setting the proportional gain Kp is changed.

[0046] As shown in Fig. 3, the control device 60 includes a rotation speed calculation unit 70. The rotation speed calculation unit 70 receives the electrical angle θr detected by the rotation angle sensor 17. The rotation speed calculation unit 70 calculates the rotation speed ωr, which is the time differential value of the detected electrical angle θr. The calculated rotation speed ωr is input to the state feedback unit 67.

[0047] Here, the zero-phase current I0 includes a third harmonic that flows at a frequency three times the rotational speed ω of the rotor 41. Therefore, when the rotational speed ω of the rotor 41 increases, the frequency of the zero-phase current I0 increases relative to the control frequency (e.g., carrier frequency and switching frequency) of the rotating electric machine 40. In this case, the influence of changes in the actual zero-phase current I0 may become significant until feedback control based on the state at the time of calculation of the zero-phase current I0r is reflected in the respective phase currents Iu, Iv, and Iw.

[0048] Therefore, the state feedback unit 67 variably sets the proportional gain Kp based on the input rotation speed ωr. This makes it possible to adjust the degree to which the currently calculated zero-phase current I0r is reflected in the feedback correction amount Vcr, taking into account the frequency of the zero-phase current I0. Therefore, a configuration suitable for reducing the zero-phase current I0 containing a frequency component dependent on the rotation speed ω of the rotor 41 can be realized.

[0049] Various methods may be used to set the proportional gain Kp. FIG. 4 shows an example of a method for setting the proportional gain Kp. When the input rotation speed ωr is equal to or lower than a predetermined specific rotation speed ω0, the state feedback unit 67 sets the proportional gain Kp to a positive value. In this case, the phase voltage command values ​​Vu*, Vv*, and Vw* are corrected so that the zero-phase current I0, which flows in the same direction as the currently calculated zero-phase current I0r, is reduced. This allows the zero-phase current I0 to be accurately reduced in the feedback control in a region where the effect of changes in the zero-phase current I0 due to the rotation of the rotor 41 is relatively small.

[0050] On the other hand, when the input rotation speed ωr is higher than the specific rotation speed ω0, the state feedback unit 67 sets the proportional gain Kp to a negative value. In this case, the phase voltage command values ​​Vu*, Vv*, and Vw* are corrected so that the zero-phase current I0, which flows in the opposite direction to the currently calculated zero-phase current I0r, is reduced. As a result, in the feedback control, the zero-phase current I0 can be accurately reduced in a region where the influence of changes in the zero-phase current I0 due to the rotation of the rotor 41 is relatively large.

[0051] The magnitude of the proportional gain Kp is set to a larger value as the input rotational speed ωr decreases in a region where the input rotational speed ωr is equal to or less than a predetermined specific rotational speed ω0. Furthermore, the magnitude of the proportional gain Kp is set to a larger value as the input rotational speed ωr increases in a region where the input rotational speed ωr is higher than the predetermined specific rotational speed ω0. As a result, a large proportional gain Kp can be used for feedback control in a region where the frequency of the zero-phase current I0 tends to be low or high relative to the control frequency of the rotating electric machine 40. This can enhance the effect of reducing the zero-phase current I0.

[0052] 5, the state feedback unit 67 may set the proportional gain Kp to 0 when the input rotation speed ωr is lower than a predetermined low rotation speed ωL. The low rotation speed ωL is a rotation speed lower than the specific rotation speed ω0. In other words, in a region where the rotation speed ω of the rotor 41 is low and the influence of the zero-phase current I0 does not pose much of a problem, the correction process of the phase voltage command values ​​Vu*, Vv*, Vw* by the corrector 66 may be stopped.

[0053] Third Embodiment A third embodiment will now be described with reference to the drawings, focusing on differences from the first embodiment. In this embodiment, in addition to correcting the phase voltage command values ​​Vu*, Vv*, and Vw*, the d-axis voltage command value Vd* and the q-axis voltage command value Vq* are corrected.

[0054] As shown in Fig. 6, the control device 60 includes a rotation speed calculation unit 70, an interference term calculation unit 71, a d-axis adder 72d, and a q-axis adder 72q. The rotation speed calculation unit 70 has the same configuration as that of the second embodiment. In this embodiment, the correction unit 66 corresponds to the "phase voltage correction unit," and the interference term calculation unit 71 and the d- and q-axis adders 72d and 72q correspond to the "dq-axis voltage correction unit."

[0055] The interference term calculation unit 71 receives as input the zero-phase current I0r calculated by the current calculation unit 65, the electrical angle θr detected by the rotation angle sensor 17, and the rotation speed ωr calculated by the rotation speed calculation unit 70. Based on the input zero-phase current I0r, electrical angle θr, and rotation speed ωr, the interference term calculation unit 71 calculates d- and q-axis correction amounts Vcd, Vcq for correcting the d- and q-axis voltage command values ​​Vd*, Vq*.

[0056] Specifically, the interference term calculation unit 71 calculates a d-axis correction amount Vcd for reducing the effect of the zero-phase current I0 interfering with the d-axis voltage Vd, and a q-axis correction amount Vcq for reducing the effect of the zero-phase current I0 interfering with the q-axis voltage Vq.

[0057] For example, in the control system 100, an interference component exists in which the zero-phase current I0r interferes with the d-axis voltage Vd and the q-axis voltage Vq. The interference term calculation unit 71 can calculate the d- and q-axis correction amounts Vcd and Vcq as amounts that cancel out this interference component. Specifically, the interference term calculation unit 71 can calculate the d- and q-axis correction amounts Vcd and Vcq using the following equations (eq1) and (eq2).

[0058] Vcd = ωr × Ld0 × sin(3θr) × I0r (eq1) Vcq = ωr × Lq0 × con(3θr) × I0r (eq2) Here, the magnitudes of the interference inductances Ld0 and Lq0 can be, for example, values ​​determined in advance based on the structure of the rotating electric machine 40.

[0059] The d-axis adder 72d adds the d-axis correction amount Vcd calculated by the interference term calculator 71 to the d-axis voltage command value Vd* calculated by the current feedback unit 63. As a result, the d-axis voltage command value Vd* is corrected based on the d-axis correction amount Vcd. The q-axis adder 72q adds the q-axis correction amount Vcq calculated by the interference term calculator 71 to the q-axis voltage command value Vq* calculated by the current feedback unit 63. As a result, the q-axis voltage command value Vq* is corrected based on the q-axis correction amount Vcq. The corrected d- and q-axis voltage command values ​​Vd* and Vq* are input to the UVW converter 64.

[0060] According to this embodiment, the d- and q-axis correction amounts Vcd and Vcq are calculated based on the calculated zero-phase current I0r, the detected electrical angle θr of the rotor 41, and the calculated rotational speed ωr. Then, the d-axis voltage command value Vd* is corrected based on the calculated d-axis correction amount Vcd, and the q-axis voltage command value Vq* is corrected based on the calculated q-axis correction amount Vcq. This makes it possible to calculate in advance the influence of the zero-phase current I0 on the d-axis voltage Vd and the q-axis voltage Vq, and to correct the d-axis voltage command value Vd* and the q-axis voltage command value Vq* to reduce the influence. As a result, the generation of the zero-phase current I0 can be appropriately suppressed.

[0061] Fourth Embodiment A fourth embodiment will be described below with reference to the drawings, focusing on differences from the third embodiment. In this embodiment, as shown in Fig. 7, the control device 60 includes an interference term calculation unit 171 and a zero-phase-sequence adder 172. In this embodiment, the correction unit 66 corresponds to a "feedback correction unit," and the interference term calculation unit 171 and the zero-phase-sequence adder 172 correspond to a "feedforward correction unit."

[0062] The interference term calculation unit 171 receives the d, q-axis current values ​​Idr, Iqr converted by the dq transformation unit 62, the electrical angle θr detected by the rotation angle sensor 17, and the rotation speed ωr calculated by the rotation speed calculation unit 70. The interference term calculation unit 171 calculates a zero-phase correction amount Vc0 for correcting the respective phase voltage command values ​​Vu*, Vv*, Vw* based on the input d, q-axis current values ​​Idr, Iqr, electrical angle θr, and rotation speed ωr.

[0063] Specifically, the interference term calculation unit 171 calculates a zero-phase correction amount Vc0 for reducing the influence of interference between the d-axis and q-axis currents Id and Iq on the zero-phase component V0 of each phase voltage Vu, Vv, and Vw. For example, the control system 100 has an interference component in which the zero-phase current Ior interferes with the d-axis voltage Vd and the q-axis voltage Vq. The interference term calculation unit 171 can calculate the zero-phase correction amount Vc0 as an amount that cancels out this interference component. Specifically, the interference term calculation unit 171 can calculate the zero-phase correction amount Vc0 using the following equation (eq3):

[0064] Vc0=ωr×L0d×sin(3θr)×Idr+ωr×L0q×cos(3θr)×Iqr (eq3) The zero-phase adder 172 adds the zero-phase correction amount Vc0 calculated by the interference term calculator 171 to the feedback correction amount Vcr calculated by the state feedback unit 67. The phase calculators 68U, 68V, 68W subtract the sum of the feedback correction amount Vcr and the zero-phase correction amount Vc0 from the corresponding voltage command values ​​Vu*, Vv*, Vw*. As a result, the phase voltage command values ​​Vu*, Vv*, Vw* are corrected based on the zero-phase correction amount Vc0. Note that the magnitudes of the interference inductances L0d and L0q in the above equation (eq3) can be, for example, values ​​determined in advance based on the structure of the rotating electric machine 40.

[0065] According to this embodiment, the zero-phase correction amount Vc0 is calculated based on the calculated d-axis current value Idr and q-axis current value Iqr, as well as the electrical angle θr and rotational speed ωr of the rotor 41. Then, the phase voltage command values ​​Vu*, Vv*, and Vw* are corrected based on the calculated zero-phase correction amount Vc0. In this case, it is possible to calculate in advance the influence of the d-axis and q-axis currents Id and Iq on the zero-phase component V0 of the phase voltages Vu, Vv, and Vw, and correct the phase voltage command values ​​Vu*, Vv*, and Vw* to reduce the influence. As a result, the generation of the zero-phase current I0 can be appropriately suppressed.

[0066] <Modification of Fourth Embodiment> As shown in FIG. 8 , the interference term calculation unit 271 may receive d- and q-axis current command values ​​Id* and Iq* instead of the calculated d- and q-axis current values ​​Idr and Iqr. Even in this case, the interference term calculation unit 271 can achieve the same function as in the fourth embodiment. For example, the interference term calculation unit 271 can calculate the zero-phase correction amount Vc0 by substituting "Id*" for "Idr" and "Iqr" for "Iq*" in equation (eq3) above. The zero-phase adder 272 adds the zero-phase correction amount Vc0 calculated by the interference term calculation unit 271 to the feedback correction amount Vcr calculated by the state feedback unit 67. In this embodiment, the interference term calculation unit 271 and the zero-phase adder 272 correspond to a "feedforward correction unit."

[0067] According to this embodiment, the zero-phase correction amount Vc0 can be calculated while avoiding the influence of noise contained in the d-axis and q-axis current values ​​Idr and Iqr, thereby realizing a configuration suitable for correcting the phase voltage command values ​​Vu*, Vv*, and Vw* using the zero-phase correction amount Vc0.

[0068] Other Embodiments The above-described embodiments may be modified as follows.

[0069] In the first embodiment, the state feedback unit 67 may perform only the proportional control and the differential control among the proportional control, the integral control, and the differential control for feedback-controlling the zero-phase current I0 to 0 (see FIG. 9 ). In this case, the state feedback unit 67 may calculate the feedback correction amount Vcr as shown in the following equation (eq4) using Kd as a differential gain.

[0070] Vcr = Kp × I0r + Kd × dI0r / dt (eq 4) According to this embodiment, proportional control and differential control are performed in the feedback control for bringing the zero-phase current I0 closer to 0. As a result, even when, for example, the rotation speed ω of the rotor 41 increases and the degree of change in the zero-phase current I0 is large, it is possible to calculate a feedback correction amount Vcr appropriate for bringing the zero-phase current I0 closer to 0. Therefore, it is possible to realize a configuration that is suitable for suppressing the generation of the AC zero-phase current I0.

[0071] In the second embodiment, the state feedback unit 67 may perform only proportional control and differential control among the proportional control, integral control, and differential control to set the calculated zero-phase current I0r to zero. In this case, the state feedback unit 67 may variably set the differential gain Kd based on the input rotation speed ωr. For example, as shown by the solid line in FIG. 10 , the state feedback unit 67 may set the differential gain Kd to a larger value as the input rotation speed ωr increases. This can increase the influence of the differential term on the proportional term when the rotation speed ω of the rotor 41 increases and the change in the zero-phase current I0r becomes larger. Furthermore, for example, as shown by the dashed line in FIG. 10 , the state feedback unit 67 may set the differential gain Kd to a smaller value as the input rotation speed ωr increases. This can avoid the influence of noise that occurs when the rotation speed ω of the rotor 41 is high. Therefore, a configuration suitable for performing proportional control and differential control can be realized in the feedback control for setting the zero-phase current I0 to zero.

[0072] In the second embodiment, the d-axis and q-axis voltage command values ​​Vd* and Vq* described in the third embodiment may be corrected. Also, in the second embodiment, the phase voltage command values ​​Vu*, Vv*, and Vw* described in the fourth embodiment may be corrected.

[0073] In the first and second embodiments, both the correction of the d-axis and q-axis voltage command values ​​Vd* and Vq* described in the third embodiment and the correction of the phase voltage command values ​​Vu*, Vv*, and Vw* described in the fourth embodiment may be performed.

[0074] In the first embodiment, the proportional gain Kp may be a predetermined negative constant. In this case, the U-phase calculation unit 68U may add the feedback correction amount Vcr to the U-phase voltage command value Vu*. The V-phase calculation unit 68V may add the feedback correction amount Vcr to the V-phase voltage command value Vv*. The W-phase calculation unit 68W may add the feedback correction amount Vcr to the W-phase voltage command value Vw*. Even in this case, the phase voltage command values ​​Vu*, Vv*, and Vw* are corrected based on the calculated zero-phase current I0r so as to reduce the zero-phase current I0.

[0075] In the second embodiment, the state feedback unit 67 may set a proportional gain Kp having a sign opposite to that of the proportional gain Kp described above with reference to Figures 4 and 5. In this case, each of the phase calculation units 68U, 68V, 68W may add a feedback correction amount Vcr to the corresponding phase voltage command value Vu*, Vv*, Vw*.

[0076] The changeover switch may be provided between the first inverter 20 and the second inverter 30 on the negative bus 12 instead of the positive bus 11. In this case, the control device 60 may set the control system 100 to the Y-drive state by turning off the changeover switch 13, turning off the second upper arm switches SUHb, SVHb, and SWHb of each phase, and turning on the second lower arm switches SULb, SVLb, and SWLb of each phase.

[0077] The control system does not need to be provided with a changeover switch. In this case, the control system is a system that is always in the H drive state.

[0078] The rotating electric machine is not limited to a permanent magnet field type synchronous machine, and may be an induction machine.

[0079] The rotating electric machine is not limited to a three-phase one, but may be a two-phase one or a four-phase or more phase one.

[0080] The semiconductor switches constituting the first inverter and the second inverter are not limited to IGBTs, but may be, for example, N-channel MOSFETs. In this case, the high-potential terminal of the switch is the drain, and the low-potential terminal is the source. Each switch also has a body diode.

[0081] The inverter, rotating electric machine, and control device may be installed in a mobile body other than a vehicle, such as an aircraft or a ship. If the mobile body is an aircraft, the rotating electric machine serves as a power source for the aircraft's flight, and if the mobile body is a ship, the rotating electric machine serves as a power source for the ship's navigation. Furthermore, the inverter, rotating electric machine, and control device may be installed in a mobile body other than a vehicle.

[0082] 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.

[0083] The following describes characteristic configurations extracted from the above-described embodiments. [Configuration 1] A rotating electric machine (40) having polyphase windings (51U, 51V, 51W); a first inverter (20) having first upper arm switches (SUHa, SVHa, SWHa) and first lower arm switches (SULa, SVLa, SWLa) connected in series for the same number of phases; a second inverter (30) having second upper arm switches (SUHb, SVHb, SWHb) and second lower arm switches (SULb, SVLb, SWLb) connected in series for the same number of phases; a positive bus (11) for each phase electrically connecting a high potential side terminal of the first upper arm switch and a high potential side terminal of the second upper arm switch; and a negative bus (12) for each phase electrically connecting a low potential side terminal of the first lower arm switch and a low potential side terminal of the second lower arm switch. a control device (60) for a rotating electric machine that is applied to a system including the above-mentioned, and performs switching control of the first inverter and the second inverter, wherein, in each phase, the first upper arm switch and the first lower arm switch are electrically connected to a first end of both ends of the winding, and in each phase, the second upper arm switch and the second lower arm switch are electrically connected to a second end of both ends of the winding, the control device comprising: a voltage calculation unit (61, 63, 64) that calculates a voltage command value for each phase to control a control variable of the rotating electric machine to a required value; a current calculation unit (65) that calculates a zero-phase current that is the sum of phase currents flowing through the windings of each phase; and a correction unit (66) that corrects the voltage command value for each phase so as to reduce the zero-phase current based on the calculated zero-phase current. [Configuration 2] The control device for a rotating electric machine according to Configuration 1, wherein the correction unit calculates a correction amount by multiplying the calculated zero-phase current by a proportional gain, and corrects the voltage command value for each phase based on the calculated correction amount, thereby performing proportional control for feedback controlling the zero-phase current to 0. [Configuration 3] The control device for a rotating electric machine according to Configuration 2, wherein the correction unit performs only the proportional control out of the proportional control and integral control for feedback controlling the zero-phase current to 0.[Configuration 4] The control device for a rotating electric machine according to Configuration 2, wherein the correction unit performs only the proportional control and the differential control out of the proportional control and the integral control and differential control for feedback-controlling the zero-phase current to zero. [Configuration 5] The control device for a rotating electric machine according to any one of Configurations 2 to 4, wherein the correction unit variably sets the proportional gain based on the rotational speed of a rotor (41) of the rotating electric machine. [Configuration 6] The control device for a rotating electric machine according to Configuration 4, wherein the correction unit performs the proportional control and the differential control by adding a derivative term obtained by multiplying the calculated time differential value of the zero-phase current by a differential gain to the correction amount, and variably sets the differential gain based on the rotational speed of the rotor (41) of the rotating electric machine. [Configuration 7] The control device for a rotary electric machine according to any one of Configurations 1 to 4, further comprising: a conversion unit (62) that converts the phase current of each phase into a d-axis current and a q-axis current based on an electrical angle of a rotor (41) in the rotary electric machine; the voltage calculation unit: sets a d-axis current command value and a q-axis current command value for controlling the control variable to the required value; calculates a d-axis voltage command value and a q-axis voltage command value to feedback control the converted d-axis current and the q-axis current to the set d-axis current command value and the q-axis current command value; converts the calculated d-axis voltage command value and the q-axis voltage command value into the voltage command value of each phase based on the electrical angle of the rotor; the correction unit is a respective phase voltage correction unit; and further comprises dq-axis voltage correction units (71, 72d, 72q) that correct the d-axis voltage command value and the q-axis voltage command value based on the calculated zero-phase current, the electrical angle, and the rotational speed of the rotor. [Configuration 8] A control device for a rotating electric machine according to any one of configurations 1 to 4, comprising: a conversion unit (62) that converts the phase current of each phase into a d-axis current and a q-axis current based on the electrical angle of a rotor (41) in the rotating electric machine; the correction unit is a feedback correction unit; and a feedforward correction unit (171, 172) that corrects the voltage command value of each phase based on the converted d-axis current and q-axis current, the electrical angle of the rotor, and the rotational speed.[Configuration 9] The control device for a rotary electric machine according to any one of Configurations 1 to 4, further comprising: a conversion unit (62) that converts the phase current of each phase into a d-axis current and a q-axis current based on an electrical angle of a rotor (41) in the rotary electric machine; the voltage calculation unit: sets a d-axis current command value and a q-axis current command value for controlling the control variable to the required value; calculates a d-axis voltage command value and a q-axis voltage command value to feedback control the converted d-axis current and the q-axis current to the set d-axis current command value and the q-axis current command value; converts the calculated d-axis voltage command value and the q-axis voltage command value into the voltage command value of each phase based on the electrical angle of the rotor; the correction unit is a feedback correction unit; and further comprises a feedforward correction unit (271, 272) that corrects the voltage command value of each phase based on the d-axis current command value and the q-axis current command value, and the electrical angle and rotational speed of the rotor. [Configuration 10] The control device for a rotating electric machine according to any one of configurations 1 to 9, wherein the rotating electric machine is a permanent magnet field type synchronous machine.

[0084] 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 rotating electric machine (40) having a multi-phase winding (51U, 51V, 51W); a first inverter (20) having first upper arm switches (SUHa, SVHa, SWHa) and first lower arm switches (SULa, SVLa, SWLa) connected in series for the number of phases; a second inverter (30) having second upper arm switches (SUHb, SVHb, SWHb) and second lower arm switches (SULb, SVLb, SWLb) connected in series for the number of phases; a positive side bus (11) electrically connecting a high potential terminal of the first upper arm switch and a high potential terminal of the second upper arm switch in each phase; and a negative side bus (12) electrically connecting a low potential terminal of the first lower arm switch and a low potential terminal of the second lower arm switch in each phase. a control device for a rotating electric machine (60) applied to a system including the above-mentioned, and performing switching control of the first inverter and the second inverter, wherein, in each phase, the first upper arm switch and the first lower arm switch are electrically connected to a first end of both ends of the winding, and in each phase, the second upper arm switch and the second lower arm switch are electrically connected to a second end of both ends of the winding, the control device for a rotating electric machine comprising: a voltage calculation unit (61, 63, 64) that calculates a voltage command value for each phase for controlling a control variable of the rotating electric machine to a required value; a current calculation unit (65) that calculates a zero-phase current which is a sum of phase currents flowing through the windings of each phase; and a correction unit (66) that corrects the voltage command value for each phase so as to reduce the zero-phase current based on the calculated zero-phase current.

2. A control device for a rotating electric machine as described in claim 1, wherein the correction unit calculates a correction amount by multiplying the calculated zero-phase current by a proportional gain, and performs proportional control to feedback control the zero-phase current to zero by correcting the voltage command value of each phase based on the calculated correction amount.

3. The control device for a rotating electric machine according to claim 2, wherein the correction unit performs only the proportional control out of the proportional control and integral control for feedback-controlling the zero-phase current to zero.

4. A control device for a rotating electric machine as described in claim 2, wherein the correction unit performs only the proportional control and the differential control out of the proportional control and the integral control and the differential control for feedback controlling the zero-phase current to zero.

5. A control device for a rotating electric machine according to any one of claims 2 to 4, wherein the correction unit variably sets the proportional gain based on the rotational speed of a rotor (41) in the rotating electric machine.

6. A control device for a rotating electric machine as described in claim 4, wherein the correction unit performs the proportional control and the differential control by adding a differential term obtained by multiplying the calculated time derivative value of the zero-phase current by a differential gain to the correction amount, and variably sets the differential gain based on the rotational speed of a rotor (41) in the rotating electric machine.

7. A control device for a rotating electric machine as claimed in any one of claims 1 to 4, further comprising a conversion unit (62) that converts the phase current of each phase into a d-axis current and a q-axis current based on the electrical angle of a rotor (41) in the rotating electric machine, wherein the voltage calculation unit: sets a d-axis current command value and a q-axis current command value for controlling the control variable to the required value, calculates a d-axis voltage command value and a q-axis voltage command value to feedback control the converted d-axis current and the q-axis current to the set d-axis current command value and q-axis current command value, converts the calculated d-axis voltage command value and the q-axis voltage command value into the voltage command value of each phase based on the electrical angle of the rotor, and the correction unit is a respective phase voltage correction unit, and further comprising a dq-axis voltage correction unit (71, 72d, 72q) that corrects the d-axis voltage command value and the q-axis voltage command value based on the calculated zero-sequence current, the electrical angle of the rotor, and the rotational speed of the rotor.

8. A control device for a rotating electric machine as described in any one of claims 1 to 4, comprising a conversion unit (62) that converts the phase current of each phase into a d-axis current and a q-axis current based on the electrical angle of a rotor (41) in the rotating electric machine, the correction unit being a feedback correction unit, and comprising a feedforward correction unit (171, 172) that corrects the voltage command value of each phase based on the converted d-axis current and q-axis current, the electrical angle of the rotor, and the rotational speed.

9. A control device for a rotating electric machine according to any one of claims 1 to 4, further comprising a conversion unit (62) that converts the phase current of each phase into a d-axis current and a q-axis current based on the electrical angle of a rotor (41) in the rotating electric machine, wherein the voltage calculation unit: sets a d-axis current command value and a q-axis current command value for controlling the control variable to the required value, calculates a d-axis voltage command value and a q-axis voltage command value to feedback control the converted d-axis current and the q-axis current to the set d-axis current command value and the q-axis current command value, and converts the calculated d-axis voltage command value and the q-axis voltage command value into the voltage command value of each phase based on the electrical angle of the rotor, and the correction unit is a feedback correction unit, and further comprising a feedforward correction unit (271, 272) that corrects the voltage command value of each phase based on the d-axis current command value and the q-axis current command value, and the electrical angle and rotational speed of the rotor.

10. A control device for a rotating electric machine according to any one of claims 1 to 4, wherein the rotating electric machine is a permanent magnet field type synchronous machine.

11. A rotating electric machine (40) having a multi-phase winding (51U, 51V, 51W); a first inverter (20) having first upper arm switches (SUHa, SVHa, SWHa) and first lower arm switches (SULa, SVLa, SWLa) connected in series for the number of phases; a second inverter (30) having second upper arm switches (SUHb, SVHb, SWHb) and second lower arm switches (SULb, SVLb, SWLb) connected in series for the number of phases; a positive side bus (11) electrically connecting a high potential terminal of the first upper arm switch and a high potential terminal of the second upper arm switch in each phase; and a negative side bus (12) electrically connecting a low potential terminal of the first lower arm switch and a low potential terminal of the second lower arm switch in each phase. a program for causing a computer (60) to execute switching control of the first inverter and the second inverter, wherein, in each phase, the first upper arm switch and the first lower arm switch are electrically connected to a first end of both ends of the winding, and in each phase, the second upper arm switch and the second lower arm switch are electrically connected to a second end of both ends of the winding, and the program causes the computer to execute a voltage calculation process for calculating a voltage command value for each phase for controlling a control variable of the rotating electric machine to a required value, a current calculation process for calculating a zero-phase current which is a sum of phase currents flowing through the windings of each phase, and a correction process for correcting the voltage command value for each phase so as to reduce the zero-phase current based on the calculated zero-phase current.

12. A rotating electric machine (40) having a multi-phase winding (51U, 51V, 51W); a first inverter (20) having first upper arm switches (SUHa, SVHa, SWHa) and first lower arm switches (SULa, SVLa, SWLa) connected in series for the number of phases; a second inverter (30) having second upper arm switches (SUHb, SVHb, SWHb) and second lower arm switches (SULb, SVLb, SWLb) connected in series for the number of phases; a positive side bus (11) electrically connecting a high potential terminal of the first upper arm switch and a high potential terminal of the second upper arm switch in each phase; and a negative side bus (12) electrically connecting a low potential terminal of the first lower arm switch and a low potential terminal of the second lower arm switch in each phase. a control method for a rotating electric machine applied to a system including the above-mentioned, for performing switching control of the first inverter and the second inverter, wherein, in each phase, the first upper arm switch and the first lower arm switch are electrically connected to a first end of both ends of the winding, and in each phase, the second upper arm switch and the second lower arm switch are electrically connected to a second end of both ends of the winding, the control method for a rotating electric machine including: a voltage calculation process that calculates a voltage command value for each phase for controlling a control variable of the rotating electric machine to a required value; a current calculation process that calculates a zero-phase current which is a sum of phase currents flowing through the windings of each phase; and a correction process that corrects the voltage command value for each phase so as to reduce the zero-phase current based on the calculated zero-phase current.

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