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

Abstract

A control device (70) comprises: a command voltage calculation unit (82) that calculates d- and q-axis main command voltages that are command values for d- and q-axis voltages to be applied to armature windings (51U-51W) of a rotary electric machine (40); and switch control units (83-88) that perform switching control of first upper and lower arm switches (SUHa-SWHa, SULa-SWLa) of a first inverter (20) and the second upper and lower arm switches (SUHb-SWHb, SULb-SWLb) of a second inverter (30) so as to satisfy the condition that the zero-phase voltage applied to the armature windings is set to a zero-phase command voltage while maintaining the d- and q-axis voltages applied to the armature windings at the calculated d- and q-axis main command voltages.

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. 2024-084964, filed on May 24, 2024, 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 the drive of 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 three-phase armature winding of the rotating electric machine, and a second inverter is electrically connected to a second end of the armature winding. A control device provided in the system controls the drive of the rotating electric machine by switching control of the first and second inverters. The control device also performs the switching control so as to reduce the ripple component of the zero-phase current flowing through the armature winding. An example of such a technology is disclosed in Patent Document 1.

[0004] Japanese Patent Application Laid-Open No. 2023-25679

[0005] A new configuration is desired that reduces the ripple component of the zero-sequence current.

[0006] A primary 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 reduce the ripple component of a 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 three-phase armature winding; a first inverter having first upper arm switches and first lower arm switches connected in series for the same number of phases, wherein the series-connected set of the first upper arm switches and the first lower arm switches is connected in parallel to a DC power source; and a second inverter having second upper arm switches and second lower arm switches connected in series for the same number of phases, wherein, in each phase, a low potential side terminal of the first upper arm switch and a high potential side terminal of the first lower arm switch are electrically connected to a first end of the armature winding; in each phase, a low potential side terminal of the second upper arm switch and a high potential side terminal of the second lower arm switch are electrically connected to a second end of the armature winding; 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 are electrically connected; and 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 are electrically connected.

[0008] The present disclosure includes a command voltage calculation unit that calculates d- and q-axis main command voltages that are command values ​​of d- and q-axis voltages to be applied to the armature windings, and a switch control unit that performs switching control of the first upper arm switch, the first lower arm switch, the second upper arm switch, and the second lower arm switch so as to satisfy the condition that the d- and q-axis voltages to be applied to the armature windings are set to the zero-phase sequence command voltages while maintaining the d- and q-axis voltages to be applied to the armature windings at the calculated d- and q-axis main command voltages.

[0009] According to the present disclosure, even when the zero-phase-sequence voltage applied to the armature winding is set to a zero-phase-sequence command voltage for reducing a ripple component contained in a zero-phase-sequence current, the d- and q-axis voltages applied to the armature winding can be maintained at the d- and q-axis main command voltages. As a result, it is possible to reduce the ripple component and prevent the control variables of the rotary electric machine from deviating from the command values ​​of the control variables corresponding to the d- and q-axis main command voltages.

[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. 1 is an overall configuration diagram of a control system according to a first embodiment, FIG. 2 is a functional block diagram of control processing executed by a control device, FIG. 3 is a diagram showing voltage vectors and sectors, FIG. 4 is a diagram showing the relationship between voltage vectors and switching states, FIG. 5 is a diagram showing a command voltage vector and output voltage vectors of first and second inverters, FIG. 6 is a diagram showing output voltage vectors of the first and second inverters when no zero-phase sequence voltage is applied, FIG. 7 is a diagram showing output voltage vectors of the first and second inverters when a zero-phase sequence voltage is applied, FIG. 8 is a diagram showing that a resultant vector becomes a zero vector, FIG. 9 is a diagram showing output voltage vectors of the first and second inverters when no zero-phase sequence voltage is applied, FIG. 10 is a diagram showing output voltage vectors of the first and second inverters when a zero-phase sequence voltage is applied, FIG. 11 is a flowchart of drive control processing of a rotating electric machine executed by a control device, and FIG. 12 is a time chart showing the transition of each duty ratio, zero-phase sequence voltage, etc. 16 is a flowchart of the drive control process of the rotating electric machine according to the third embodiment; FIG. 17 is a diagram showing the output voltage vectors of the first and second inverters and effective voltage vectors corresponding to the zero-phase voltage; FIG. 18 is a diagram showing the output voltage vectors of the first and second inverters when a zero-phase voltage is applied; FIG. 19 is a diagram showing the output voltage vectors of the first and second inverters when a zero-phase voltage is applied; FIG. 20 is a functional block diagram of the control process executed by the control device; FIG. 21 is a flowchart of the drive control process of the rotating electric machine;

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

[0012] As shown in Fig. 1, the control system 100 includes a battery 10, which is a DC power supply, 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, each of the switches SUHa to SWLa and SUHb to SWLb is a voltage-controlled semiconductor switching element, more specifically, an IGBT. In this case, the high-potential terminal of each of the switches SUHa to SWLa and SUHb to SWLb is the collector, and the low-potential terminal is the emitter. A freewheel diode is connected in anti-parallel to each of the switches SUHa to SWLb. Specifically, U-, V-, and W-phase first upper-arm diodes DUHa, DVHa, and DWHa are connected in anti-parallel to the U-, V-, and W-phase first upper-arm switches SUHa, SVHa, and SWHa, respectively, and U-, V-, and W-phase first lower-arm diodes DULa, DVLa, and DWLa are connected in anti-parallel to the U-, V-, and W-phase first lower-arm switches SULa, SVLa, and SWLa, respectively. U, V, W-phase second upper-arm diodes DUHb, DVHb, DWHb are connected in anti-parallel to the U, V, W-phase second upper-arm switches SUHb, SVHb, SWHb, and U, V, W-phase second lower-arm diodes DULb, DVLb, DWLb are connected in anti-parallel to the U, V, W-phase second lower-arm switches SULb, SVLb, SWLb.

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

[0017] The control system 100 includes a power switch 14. The power switch 14 is, for example, a semiconductor switching element or a mechanical relay. The power switch 14 connects the collectors of the first upper arm switches SUHa, SVHa, and SWHa of each phase to the positive terminal of the battery 10. When the power switch 14 is turned on, it electrically connects the positive terminal of the battery 10 to the collectors of the first upper arm switches SUHa, SVHa, and SWHa of each phase. When the power switch 14 is turned off, it electrically disconnects the positive terminal of the battery 10 from the collectors of the first upper arm switches SUHa, SVHa, and SWHa of each phase.

[0018] The control system 100 includes a capacitor 15. The capacitor 15 functions as a smoothing capacitor. The capacitor 15 is connected in parallel to the series-connected body of the first upper arm switches SUHa to SWHa of each phase and the first lower arm switches SULa to SWLa of each phase.

[0019] The rotating electric machine 40 is an on-board main engine that serves as a power source for running the vehicle. The rotating electric machine 40 includes a rotor 41 and a stator 50. The rotor 41 is capable of transmitting power to the drive wheels 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.

[0020] The stator 50 includes a U-phase winding 51U, a V-phase winding 51V, and a W-phase winding 51W as armature windings. The phase windings 51U, 51V, and 51W are arranged at intervals of 120 electrical degrees on the stator core that constitutes the stator 50. The phase windings 51U, 51V, and 51W are open windings.

[0021] In each phase, the emitters of first upper switches SUHa, SVHa, SWHa and the collectors of first lower switches SULa, SVLa, SWLa are connected to first ends 51Ua, 51Va, 51Wa of the windings 51U, 51V, 51W, respectively. In each phase, the emitters of second upper switches SUHb, SVHb, SWHb and the collectors of second lower switches SULb, SVLb, SWLb are connected to second ends 51Ub, 51Vb, 51Wb of the windings 51U, 51V, 51W, respectively.

[0022] The control system 100 includes a current sensor 60 , a rotation angle sensor 61 , and a voltage sensor 62 .

[0023] The current sensor 60 detects the phase current flowing through each of the phase windings 51U, 51V, 51W. In this embodiment, the current sensor 60 is provided at one of both ends of each of the phase windings 51U, 51V, 51W closer to the first inverter 20. Note that the current sensor 60 may also be provided at one of both ends of each of the phase windings 51U, 51V, 51W closer to the second inverter 30.

[0024] The rotation angle sensor 61 is, for example, a resolver, and detects the electrical angle of the rotor 41. The voltage sensor 62 detects the voltage between the terminals of the capacitor 15.

[0025] The detection values ​​of the sensors 60 to 62 are input to a control device 70 included in the control system 100. The control device 70 is an electronic control unit (ECU) that performs various controls of the control system 100, and includes a processor 71 and a storage unit 72 as hardware. In the control system 100, each on-board device can be controlled by an ECU corresponding to that device. However, for convenience, multiple ECUs are shown as a single control device 70 in FIG. 1.

[0026] The memory unit 72 includes a memory and a storage as hardware. The memory is a storage device for storing data used in the processing of the control device 70. The memory provides the processor 71 with a working area for temporary use when the processor 71 performs processing, for example. The memory includes, for example, a ROM or a RAM. The storage is a storage device for storing various programs and data to be read and executed by the processor 71, and is a non-transitory tangible storage medium. The storage includes, for example, an HDD or a flash memory. The storage stores program information and the like for the processing shown in FIGS. 2 and 11, which will be described later.

[0027] For example, program information stored on a non-transient physical recording medium is installed in the storage unit 72. The recording medium is, for example, a USB memory, a CD-ROM, or a DVD. Also, for example, program information transmitted via a communication network, such as over the air (OTA), is installed in the storage unit 72.

[0028] The control device 70 controls the switches SUHa to SWLa of the first inverter 20 and the switches SUHb to SWLb of the second inverter 30 to turn on or off while the power switch 14 is on, in order to control the control variable of the rotating electric machine 40 to a command value. The control variable is, for example, torque or the rotational speed of the rotor 41. In this embodiment, the control variable is torque.

[0029] FIG. 2 is a block diagram showing the control process of the rotating electrical machine 40 executed by the control device 70. As shown in FIG.

[0030] The command value calculation unit 80 calculates a d-axis main command current Id* and a q-axis main command current Iq* in a dq coordinate system, which is a two-phase rotating coordinate system, based on the command torque Trq* received from a control device that is higher in level than the control device 70. The combination of the d- and q-axis main command currents Id* and Iq* is a combination that sets the torque generated by the rotary electric machine 40 to the command torque Trq*.

[0031] The two-phase conversion unit 81 calculates the d-axis current Idr and the q-axis current Iqr based on the phase currents Iur, Ivr, and Iwr detected by the current sensor 60 and the electrical angle θr detected by the rotation angle sensor 61. FIG. 3 shows a reference axis (specifically, a U-phase axis LU) extending from an origin O in a three-phase voltage vector space. FIG. 3 also shows α and β axes, which form a two-phase fixed coordinate system, and d and q axes, which form a two-phase rotating coordinate system. The angle between the α axis and the d axis is the electrical angle θr.

[0032] In the voltage vector space shown in FIG. 3 , the U-phase axis LU, the V-phase axis LV extending from the origin O, and the W-phase axis LW extending from the origin O are offset by 120° in electrical angle. In FIG. 3 , voltage vectors that can be output by each inverter 20, 30 are indicated by V0 to V7. The 0th and 7th voltage vectors V0 and V7 are reactive voltage vectors, and the 1st to 6th voltage vectors V1 to V6 are active voltage vectors. The relationship between each voltage vector V0 to V7 and the switching states of the upper and lower arm switches is shown in FIG. 4 . In FIG. 4 , "1" indicates that the upper arm switch is on and the lower arm switch is off, and "0" indicates that the upper arm switch is off and the lower arm switch is on. The accompanying numbers indicate the switching states of the U, V, and W phases, from left to right. For example, in the case of the first voltage vector V1 defined by "100", the U-phase upper arm switch and the V- and W-phase lower arm switches are turned on, and the U-phase lower arm switch and the V- and W-phase upper arm switches are turned off.

[0033] The current feedback unit 82 calculates a d-axis main command voltage Vdm and a q-axis main command voltage Vqm based on the d- and q-axis main command currents Id* and Iq* and the d- and q-axis currents Idr and Iqr. The d-axis main command voltage Vdm is the d-axis component of the command voltage vector Vtr, and the q-axis main command voltage Vqm is the q-axis component of the command voltage vector Vtr. The command voltage vector Vtr is a voltage vector required to make the torque generated by the rotary electric machine 40 equal to the command torque Trq*.

[0034] The current feedback unit 82 calculates a d-axis current deviation, which is the difference between the d-axis main command current Id* and the d-axis current Idr, and calculates a d-axis main command voltage Vdm as a manipulated variable for feedback-controlling the calculated d-axis current deviation to 0. The current feedback unit 82 calculates a q-axis current deviation, which is the difference between the q-axis main command current Iq* and the q-axis current Iqr, and calculates a q-axis main command voltage Vqm as a manipulated variable for feedback-controlling the calculated q-axis current deviation to 0. The feedback control is, for example, proportional-plus-integral control.

[0035] 5 , the current feedback unit 82 distributes the d- and q-axis main command voltages Vdm and Vqm to the first and second inverters 20, 30 in order to realize the command voltage vector Vtr as a resultant vector of the first command vector Vinv1 and the second command vector Vinv2. The first command vector Vinv1 is a command value of the output voltage vector of the first inverter 20, and the second command vector Vinv2 is a command value of the output voltage vector of the second inverter 30.

[0036] The current feedback unit 82 calculates a d-axis command voltage Vd* (=Vdm / 2) for the first and second inverters 20, 30 by dividing the d-axis main command voltage Vdm by √3. The current feedback unit 82 also calculates a q-axis command voltage Vq* (=Vqm / 2) for the first and second inverters 20, 30 by dividing the q-axis main command voltage Vqm by √3. In other words, the magnitude of the first command vector Vinv1 and the magnitude of the second command vector Vinv2 are the same. The angle between the command voltage vector Vtr and the d-axis is Tan^(-1)(Vq* / Vd*) (see FIG. 3). In this embodiment, the current feedback unit 82 corresponds to the "command voltage calculation unit."

[0037] The vector shift unit 85 calculates a shift amount ΔD based on the electrical angle θr, the power supply voltage VB detected by the voltage sensor 62, the zero-phase command voltage Vz*, and the d-axis and q-axis command voltages Vd* and Vq*. The zero-phase command voltage Vz* is a command value for the zero-phase voltage to be applied to the U-, V-, and W-phase windings 51U, 51V, and 51W. The zero-phase command voltage Vz* is a value set to reduce the ripple component of the zero-phase current flowing through the U-, V-, and W-phase windings 51U, 51V, and 51W.

[0038] The vector shift unit 85 may calculate the zero-phase command voltage Vz* as a manipulated variable for feedback-controlling the zero-phase current Izr flowing through each of the phase windings 51U, 51V, and 51W to a target value (e.g., 0). The vector shift unit 85 may calculate the zero-phase current Izr as the average value of the U-, V-, and W-phase currents detected by the current sensor 60.

[0039] The shift amount ΔD is a characteristic parameter for maintaining the torque generated by the rotary electric machine 40 at the command torque Trq* while controlling the actual zero-phase-sequence voltage to the zero-phase-sequence command voltage Vz*. Based on the shift amount ΔD, the first command vector Vinv1 is corrected to become the first correction vector Vm1, and the second command vector Vinv2 is corrected to become the second correction vector Vm2 (see FIGS. 6 and 7 ). A method for calculating the shift amount ΔD by the vector shift unit 85 will be described in detail later.

[0040] The first modulation unit 86 generates drive signals for the switches SUHa to SWLa of the first inverter 20 in order to set the output voltage vector of the first inverter 20 to the first correction vector Vm1. The drive signals consist of switch on and off commands. The first modulation unit 86 controls the charge / discharge current of the gates of the switches SUHa to SWLa of the first inverter 20 based on the generated drive signals. This controls the on / off of the switches SUHa to SWLa of the first inverter 20 in accordance with the drive signals.

[0041] The second modulation unit 87 generates drive signals for the switches SUHb to SWLb of the second inverter 30 to set the output voltage vector of the second inverter 30 to the second correction vector Vm2. Based on the generated drive signals, the second modulation unit 87 controls the charge / discharge currents of the gates of the switches SUHb to SWLb of the second inverter 30. As a result, the on / off of the switches SUHb to SWLb of the second inverter 30 is controlled in accordance with the drive signals.

[0042] In this embodiment, the first angle conversion unit 83, the second angle conversion unit 84, the vector shift unit 85, the first modulation unit 86, and the second modulation unit 87 correspond to a "switch control unit."

[0043] Next, a method for calculating the shift amount ΔD in the vector shift unit 85 will be described.

[0044] 5 shows the command voltage vector Vtr, the first command vector Vinv1, and the second command vector Vinv2 in the voltage vector space. The angle formed by the first command vector Vinv1 and the second command vector Vinv2 is set to 120°.

[0045] As shown in Figure 3, six sectors are defined in the voltage vector space. Figure 3 shows sectors 1 to 6, which divide the voltage vector space into six. Each sector is an area sandwiched between two effective voltage vectors that form an electrical angle of 60 degrees. In Figure 3, the value of the zero-phase sequence voltage corresponding to each vector V0 to V7 is written in parentheses next to each vector V0 to V7.

[0046] The value of the shift amount ΔD differs depending on whether the first command vector Vinv1 is in an odd-numbered sector or an even-numbered sector among the first to sixth sectors.

[0047] First, a case where the first command vector Vinv1 exists in an odd-numbered sector will be described. In the following, a case where the first command vector Vinv1 exists in the first sector will be described as an example.

[0048] A case where the zero-phase sequence command voltage Vz* is set to 0 will be described using Fig. 6. In Fig. 6, "D1 x V1" is the component of the first command vector Vinv1 in the direction of the U-phase axis LU. "D2 x V2" is the component of the first command vector Vinv1 in the direction in which the second voltage vector V2 extends.

[0049] "D1×V3" is the component of the second command vector Vinv2 in the direction in which the third voltage vector V3 extends. The magnitude of "D1×V3" is equal to "D1×V1." "D2×V4" is the component of the second command vector Vinv2 in the direction of the V-phase axis LV. The magnitude of "D2×V4" is equal to "D2×V2."

[0050] The command voltage vector Vtr is expressed by the following equation (eq1).

[0051] When the corresponding zero-phase-sequence voltages are substituted for V1, V3, V2, and V4 in the above equation (eq1), the zero-phase-sequence voltage Vz becomes 0 as shown in the following equation (eq2).

[0052] A case where the zero-phase command voltage Vz* is set to a value other than 0 will be described with reference to FIG.

[0053] In Fig. 7, "D1 x V1 - ΔD x V1" is a vector obtained by correcting "D1 x V1" shown in Fig. 6 by "ΔD x V1". "D2 x V2 + 2 x ΔD x V2" is a vector obtained by correcting "D2 x V2" shown in Fig. 6 by "2 x ΔD x V2". As a result, the first command vector Vinv1 shown in Fig. 6 becomes the first correction vector Vm1.

[0054] "D1×V3+2×ΔD×V3" is a vector obtained by correcting "D1×V3" shown in FIG. 6 by "2×ΔD×V3." "D2×V4-ΔD×V4" is a vector obtained by correcting "D2×V4" shown in FIG. 6 by "ΔD×V4." As a result, the second command vector Vinv2 shown in FIG. 6 is changed to the second correction vector Vm2. The magnitude of the first correction vector Vm1 is equal to the magnitude of the second correction vector Vm2. Even if the first and second command vectors Vinv1 and Vinv2 are corrected to the first and second correction vectors Vm1 and Vm2 to reduce the ripple component of the zero-phase current, the resultant vector of the first and second correction vectors Vm1 and Vm2 is maintained as the command voltage vector Vtr. The command voltage vector Vtr in this case is expressed by the following equation (eq3):

[0055] The resultant vector of the effective voltage vector of the first correction vector Vm1 corresponding to the zero-phase-sequence command voltage Vz* and the effective voltage vector of the second correction vector Vm2 corresponding to the zero-phase-sequence command voltage Vz* is a zero vector. More specifically, as shown in FIG. 8 , there is a relationship of "-V1 + 2 × V2 - 2 × V3 + V4 = 0." Applying this relationship to the above equation (eq3) leads to the following equation (eq4). The above equation (eq1) and the below equation (eq4) are the same. In other words, even when the zero-phase-sequence command voltage Vz* is applied, the command voltage vector Vtr is the same as the command voltage vector Vtr when the zero-phase-sequence command voltage Vz* is set to 0.

[0056] On the other hand, when the corresponding zero-phase voltages are substituted for V1, V3, V2, and V4 in the above equation (eq3), the following equation (eq5) is derived.

[0057] That is, when the vector shift unit 85 determines that the first command vector Vinv1 is present in an odd-numbered sector, it calculates a shift amount ΔD expressed by the following equation (eq6) based on the power supply voltage VB and the zero-phase-sequence command voltage Vz*. The shift amount ΔD becomes smaller as the power supply voltage VB becomes higher or the zero-phase-sequence command voltage Vz* becomes smaller.

[0058] In the example shown in Figure 7, the third and fourth voltage vectors V3 and V4 sandwiching the second correction vector Vm2, and the first and second voltage vectors V1 and V2 sandwiching the first correction vector Vm1 appear every switching period of the first and second inverters 20 and 30.

[0059] Next, a case where the first command vector Vinv1 is present in an even-numbered sector will be described. In the following, a case where the first command vector Vinv1 is present in the second sector will be described as an example.

[0060] A case where the zero-phase sequence command voltage Vz* is set to 0 will be described using Fig. 9. In Fig. 9, "D1 x V2" is the component of the first command vector Vinv1 in the direction in which the second voltage vector V2 extends. "D2 x V3" is the component of the first command vector Vinv1 in the direction in which the V-phase axis LV extends.

[0061] "D1×V4" is the component of the second command vector Vinv2 in the direction in which the fourth voltage vector V4 extends. The magnitude of "D1×V4" is equal to "D1×V2". "D2×V5" is the component of the second command vector Vinv2 in the direction of the W-phase axis LW. The magnitude of "D2×V5" is equal to "D2×V3".

[0062] The command voltage vector Vtr is expressed by the following equation (eq7).

[0063] When the corresponding zero-phase-sequence voltages are substituted for V2, V4, V3, and V5 in the above equation (eq7), the zero-phase-sequence voltage Vz becomes 0, as in the case of odd-numbered sectors.

[0064] A case where the zero-phase command voltage Vz* is set to a value other than 0 will be described with reference to FIG.

[0065] "D1×V2-ΔD×V2" is a vector obtained by correcting "D1×V2" shown in Fig. 9 by "ΔD×V2". "D2×V3+2×ΔD×V3" is a vector obtained by correcting "D2×V3" shown in Fig. 9 by "2×ΔD×V3". As a result, the first command vector Vinv1 shown in Fig. 9 becomes the first correction vector Vm1.

[0066] "D1×V4+2×ΔD×V4" is a vector obtained by correcting "D1×V4" shown in FIG. 9 by "2×ΔD×V4." "D2×V5-ΔD×V5" is a vector obtained by correcting "D2×V5" shown in FIG. 9 by "ΔD×V5." As a result, the second command vector Vinv2 shown in FIG. 9 is changed to the second correction vector Vm2. The magnitude of the first correction vector Vm1 is equal to the magnitude of the second correction vector Vm2. Even if the first and second command vectors Vinv1 and Vinv2 are corrected to the first and second correction vectors Vm1 and Vm2, the resultant vector of the first and second correction vectors Vm1 and Vm2 is maintained as the command voltage vector Vtr. The command voltage vector Vtr in this case is expressed by the following equation (eq8).

[0067] In the above equation (eq8), by using the relationship "-V2 + 2 × V3 - 2 × V4 + V5 = 0," the following equation (eq9) is derived. That is, as in the odd-numbered sectors, even when the zero-phase-sequence command voltage Vz* is applied, the command voltage vector Vtr is the same as the command voltage vector Vtr when the zero-phase-sequence command voltage Vz* is set to 0.

[0068] On the other hand, when the corresponding zero-phase voltages are substituted for V2, V3, V4, and V5 in the above equation (eq8), the following equation (eq10) is derived.

[0069] That is, when the vector shift unit 85 determines that the first command vector Vinv1 is present in an even sector, it calculates a shift amount ΔD expressed by the following equation (eq11) based on the power supply voltage VB and the zero-phase command voltage Vz*. As shown in the following equation (eq11) and the above equation (eq6), the shift amount ΔD in the even sector has the same absolute value as the shift amount ΔD in the odd sector, but is opposite in sign.

[0070] 11 is a flowchart of the control process for the rotary electric machine 40 executed by the control device 70. This process is repeatedly executed at a predetermined control cycle, for example.

[0071] In step S10, the vector shift unit 85 determines whether the first command vector Vinv1 of the first inverter 20 is in any of the first to sixth sectors. An example of the determination method will be described below.

[0072] First, the angle θvt1 formed by the U-phase axis LU and the first command vector Vinv1 is calculated using the following equation (eq12) based on the d-axis and q-axis command voltages Vd* and Vq* and the electrical angle θr.

[0073] Next, as shown in the following equation (eq13), if it is determined that the remainder when the calculated angle θvt1 is divided by 2π / 3 (120°) is equal to or less than π / 3 (60°), it is determined that the first command vector Vinv1 is in an odd sector.

[0074] On the other hand, as shown in the following equation (eq14), if it is determined that the remainder when the calculated angle θvt1 is divided by 2π / 3 is less than π / 3, it is determined that the first command vector Vinv1 is in an even sector.

[0075] In step S11, it is determined whether the sector identified in step S10 is an odd-numbered sector or an even-numbered sector. If it is determined in step S11 that the sector is an odd-numbered sector, the process proceeds to step S12. In step S12, the vector shift unit 85 calculates the shift amount ΔD based on the above equation (eq6).

[0076] In step S13, the first modulation unit 86 calculates the first U-, V-, and W-phase duty ratios Du1, Dv1, and Dw1 based on the electrical angle θr, the d- and q-axis command voltages Vd* and Vq*, the power supply voltage VB, and the shift amount Δ using the following equation (eq15):

[0077] In step S14, the first modulation unit 86 determines the maximum duty ratio of the calculated first U-, V-, and W-phase duty ratios Du1, Dv1, and Dw1 as a first maximum duty ratio drmax1, a minimum duty ratio as a first minimum duty ratio drmin1, and an intermediate duty ratio as a first intermediate duty ratio drmid1. Each of the duty ratios drmax1, drmid1, and drmin1 may be a positive value or a negative value.

[0078] In step S14, normalized minimum, medium, and maximum duty ratios Dmin1, Dmid1, and Dmax1 are calculated based on the duty ratios drmax1, drmid1, and drmin1 and the shift amount ΔD using the following equations (eq16), (eq17), and (eq18).

[0079]

[0080]

[0081] The normalized minimum, medium, and maximum duty ratios Dmin1, Dmid1, and Dmax1 are values ​​that are equal to or greater than 0 and equal to or less than 1. There is also a relationship of "Dmin1+Dmax1=1."

[0082] Then, of the calculated first U, V, and W phase duty ratios Du1, Dv1, and Dw1, the phase with the maximum duty ratio is designated as the maximum phase, the phase with the minimum duty ratio is designated as the minimum phase, and the phase with the intermediate duty ratio is designated as the intermediate phase.

[0083] The normalized maximum duty ratio Dmax1 is the duty ratio of the maximum phase, the normalized intermediate duty ratio Dmin1 is the duty ratio of the intermediate phase, and the normalized minimum duty ratio Dmin1 is the duty ratio of the minimum phase. For example, if the maximum phase is the U phase, the intermediate phase is the V phase, and the minimum phase is the W phase, the normalized maximum duty ratio Dmax1 is the duty ratio of the U phase, the normalized intermediate duty ratio Dmin1 is the duty ratio of the V phase, and the normalized minimum duty ratio Dmin1 is the duty ratio of the W phase.

[0084] In step S15, the second modulation unit 87 calculates the second U-, V-, and W-phase duty ratios Du2, Dv2, and Dw2 using the following equation (eq19) based on the electrical angle θr, the d- and q-axis command voltages Vd* and Vq*, the power supply voltage VB, and the shift amount Δ.

[0085] In step S16, the second modulator 87 determines the maximum duty ratio of the calculated second U-, V-, and W-phase duty ratios Du2, Dv2, and Dw2 as a second maximum duty ratio drmax2, the minimum duty ratio as a second minimum duty ratio drmin2, and the intermediate duty ratio as a second intermediate duty ratio drmid2. Each of the duty ratios drmax2, drmid2, and drmin2 may be a negative value as well as a positive value.

[0086] In step S16, normalized minimum, medium, and maximum duty ratios Dmin2, Dmid2, and Dmax2 are calculated based on the duty ratios drmax2, drmid2, and drmin2 and the shift amount ΔD using the following equations (eq20), (eq21), and (eq22).

[0087]

[0088]

[0089] The normalized minimum, medium, and maximum duty ratios Dmin2, Dmid2, and Dmax2 are values ​​that are equal to or greater than 0 and equal to or less than 1. There is also a relationship of "Dmin2+Dmax2=1."

[0090] Then, of the calculated second U, V, and W phase duty ratios Du2, Dv2, and Dw2, the phase with the maximum duty ratio is designated as the maximum phase, the phase with the minimum duty ratio is designated as the minimum phase, and the phase with the intermediate duty ratio is designated as the intermediate phase.

[0091] The normalized maximum duty ratio Dmax2 is the duty ratio of the maximum phase, the normalized intermediate duty ratio Dmin2 is the duty ratio of the intermediate phase, and the normalized minimum duty ratio Dmin2 is the duty ratio of the minimum phase.

[0092] In step S17, the first modulation unit 86 generates drive signals for the switches SUHa to SWLa of the first inverter 20 based on a comparison of the normalized maximum duty ratio Dmax1, the normalized intermediate duty ratio Dmin1, and the normalized minimum duty ratio Dmin1 calculated in step S14 with the carrier signal Sg. In this embodiment, the carrier signal Sg is a triangular wave signal with equal increasing and decreasing speeds. In this embodiment, the carrier signal Sg has a maximum value of 1, a minimum value of 0, and a median value of 1 / 2.

[0093] In addition, in step S17, the second modulation unit 87 generates drive signals for each switch SUHb to SWLb of the second inverter 30 based on a comparison of the normalized maximum duty ratio Dmax2, normalized intermediate duty ratio Dmin2, and normalized minimum duty ratio Dmin2 calculated in step S16 with the carrier signal Sg.

[0094] If it is determined in step S11 that the sector is an even number sector, the process proceeds to step S 18. In step S18, the vector shifter 85 calculates the shift amount ΔD based on the above equation (eq11).

[0095] In step S19, the first modulator 86 calculates the first U-, V-, and W-phase duty ratios Du1, Dv1, and Dw1 using the above equation (eq15), similarly to step S13.

[0096] In step S20, similar to step S14, the maximum duty ratio of the calculated first U-, V-, and W-phase duty ratios Du1, Dv1, and Dw1 is set to the first maximum duty ratio drmax1, the minimum duty ratio is set to the first minimum duty ratio drmin1, and the intermediate duty ratio is set to the first intermediate duty ratio drmid1.

[0097] In step S20, the normalized minimum and maximum duty ratios Dmin1 and Dmax1 are calculated using the above equations (eq16) and (eq18) based on the duty ratios drmax1, drmid1, and drmin1 and the shift amount ΔD. Also, the normalized intermediate duty ratio Dmid1 is calculated using the following equation (eq23).

[0098] Then, of the calculated first U, V, and W phase duty ratios Du1, Dv1, and Dw1, the phase with the maximum duty ratio is designated as the maximum phase, the phase with the minimum duty ratio is designated as the minimum phase, and the phase with the intermediate duty ratio is designated as the intermediate phase.

[0099] The normalized maximum duty ratio Dmax1 is the duty ratio of the maximum phase, the normalized intermediate duty ratio Dmin1 is the duty ratio of the intermediate phase, and the normalized minimum duty ratio Dmin1 is the duty ratio of the minimum phase.

[0100] In step S21, similarly to step S15, the second U-, V-, and W-phase duty ratios Du2, Dv2, and Dw2 are calculated by the above equation (eq19).

[0101] In step S21, of the calculated second U-, V-, and W-phase duty ratios Du2, Dv2, and Dw2, the maximum duty ratio is set to the second maximum duty ratio drmax2, the minimum duty ratio is set to the second minimum duty ratio drmin2, and the intermediate duty ratio is set to the second intermediate duty ratio drmid2.

[0102] In step S22, similarly to step S16, the normalized minimum and maximum duty ratios Dmin2 and Dmax2 are calculated by the above equations (eq20) and (eq22). Also, the normalized intermediate duty ratio Dmin2 is calculated by the following equation (eq24).

[0103] Of the calculated second U-, V-, and W-phase duty ratios Du2, Dv2, and Dw2, the phase with the maximum duty ratio is designated as the maximum phase, the phase with the minimum duty ratio is designated as the minimum phase, and the phase with the intermediate duty ratio is designated as the intermediate phase.

[0104] The normalized maximum duty ratio Dmax2 is set as the duty ratio of the maximum phase, the normalized intermediate duty ratio Dmin2 is set as the duty ratio of the intermediate phase, and the normalized minimum duty ratio Dmin2 is set as the duty ratio of the minimum phase.Then, the process proceeds to step S17.

[0105] As a result of the processing in step S17, two effective voltage vectors sandwiching the first correction vector Vm1 and having a phase difference of 60°, two effective voltage vectors sandwiching the second correction vector Vm2 and having a phase difference of 60°, a zeroth voltage vector V0 that turns off the first and second upper arm switches SUHa, SVHa, SWHa, SUHb, SVHb, and SWHb of each phase, and a seventh voltage vector V7 that turns on the first and second upper arm switches SUHa, SVHa, SWHa, SUHb, SVHb, and SWHb of each phase appear every switching period.

[0106] 12 shows a time chart of an example of control in this embodiment. In FIG. 12, (a) shows the transitions of the duty ratios Dmax1, Dmid1, Dmin1, Dmax2, Dmid2, and Dmin2 and the carrier signal Sg, (b) and (c) show the transitions of the first and second common-mode voltages Vc1 and Vc2, and (d) shows the transition of the zero-phase voltage. The first common-mode voltage Vc1 is the sum of the U-, V-, and W-phase output voltages of the first inverter 20 divided by √3, and the second common-mode voltage Vc2 is the sum of the U-, V-, and W-phase output voltages of the second inverter 30 divided by √3.

[0107] 12, the periods T1A, T1B, T2A, and T2B during which the effective voltage vectors output from the first and second inverters 20 and 30 appear are adjusted. As a result, two periods during which the zero-phase voltage has a value other than 0 appear in one period Tg of the carrier signal Sg (i.e., one switching period of each inverter 20 and 30).

[0108] FIG. 13 shows the transitions of the zero-phase voltage and other parameters in a comparative example different from this embodiment. The comparative example has the configuration described in Patent Document 1. FIG. 13( a) shows the transitions of the U-, V-, and W-phase duty ratios Da, Db, and Dc. In the comparative example, control is performed so that the appearance periods T1A, T1B, T2A, and T2B of the effective voltage vectors are the same. In this case, the period during which the zero-phase voltage is a value other than 0 in one switching period is longer than in this embodiment, and the zero-phase voltage contains harmonic components.

[0109] According to the present embodiment described above, even when a zero-phase voltage is applied to each phase winding 51U, 51V, 51W to reduce the ripple component of the zero-phase current, the torque of the rotating electric machine 40 can be maintained at the command torque Trq*.

[0110] <Modification of First Embodiment> Control may be performed according to a flowchart shown in Fig. 14 instead of the flowchart shown in Fig. 11. The process shown in Fig. 14 is repeatedly executed by the control device 70, for example, at a predetermined control cycle.

[0111] If it is determined in step S11 that the sector is odd, the process proceeds to step S30, where the vector shift unit 85 determines whether or not there is a request to set the zero-phase sequence command voltage Vz* to 0. For example, it is determined that there is such a request when utilizing the torque increase effect of the rotating electrical machine 40 that accompanies the flow of zero-phase sequence current.

[0112] If it is determined in step S30 that there is no request, the process proceeds to step S12. On the other hand, if it is determined in step S30 that there is a request, the process proceeds to step S31, where the vector shift unit 85 sets the zero-phase command voltage Vz* to 0.

[0113] Since the angle between the first and second command vectors Vinv1 and Vinv2 is 120°, as shown in the above equation (eq2), even if the zero-phase sequence command voltage Vz* is 0, the zero-phase sequence voltage of each of the phase windings 51U, 51V, and 51W is 0. After completing the processing of step S31, the process proceeds to step S13.

[0114] If it is determined in step S11 that the sector is an even sector, the process proceeds to step S32, where it is determined whether or not there is a request in the vector shift unit 85 to set the zero-phase command voltage Vz* to zero.

[0115] If it is determined in step S32 that there is no request, the process proceeds to step S18. On the other hand, if it is determined in step S32 that there is a request, the process proceeds to step S33, where the vector shift unit 85 sets the zero-phase command voltage Vz* to 0. Thereafter, the process proceeds to step S19.

[0116] 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 control device 70 controls the switching of the first and second inverters 20, 30 so that the reactive voltage vector appearing in one switching period is the zeroth voltage vector V0, not the seventh voltage vector V7.

[0117] 15 is a flowchart of the control process for the rotary electric machine 40 executed by the control device 70. This process is executed repeatedly at a predetermined control cycle, for example.

[0118] After completing the process of step S13, the process proceeds to step S40, where the first modulation unit 86 calculates the normalized minimum, medium, and maximum duty ratios Dmin1, Dmid1, and Dmax1, similar to step S14 in Fig. 11. Here, the final normalized minimum, medium, and maximum duty ratios Dmin1, Dmid1, and Dmax1 are calculated by subtracting the calculated normalized minimum duty ratio Dmin1 from the normalized minimum, medium, and maximum duty ratios Dmin1, Dmid1, and Dmax1 so that the calculated normalized minimum duty ratio Dmin1 becomes 0. The calculated final normalized minimum, medium, and maximum duty ratios Dmin1, Dmid1, and Dmax1 are used in step S17.

[0119] After completing the process of step S15, the process proceeds to step S41, where the second modulation unit 87 calculates the normalized minimum, medium, and maximum duty ratios Dmin2, Dmid2, and Dmax2, similar to step S16 in Fig. 11. Here, the final normalized minimum, medium, and maximum duty ratios Dmin2, Dmid2, and Dmax2 are calculated by subtracting the calculated normalized minimum duty ratio Dmin2 from the normalized minimum, medium, and maximum duty ratios Dmin2, Dmid2, and Dmax2 so that the calculated normalized minimum duty ratio Dmin2 becomes 0. The calculated final normalized minimum, medium, and maximum duty ratios Dmin2, Dmid2, and Dmax2 are used in step S17.

[0120] According to the present embodiment described above, the only reactive voltage vector that appears in each switching period is the zeroth voltage vector V. This reduces the ripple component of the zero-phase current and the switching loss of the first and second inverters 20 and 30.

[0121] Third Embodiment A third embodiment will now be described with reference to the drawings, focusing on differences from the second embodiment. In this embodiment, the control device 70 controls the switching of the first and second inverters 20, 30 so that the reactive voltage vector appearing in one switching period is not the zeroth voltage vector V0 but the seventh voltage vector V7.

[0122] 16 is a flowchart of the control process for the rotary electric machine 40 executed by the control device 70. This process is repeatedly executed, for example, at a predetermined control cycle.

[0123] After completing the process of step S13, the process proceeds to step S50, where the first modulation unit 86 calculates the normalized minimum, medium, and maximum duty ratios Dmin1, Dmid1, and Dmax1 in the same manner as step S14 in Fig. 11. Here, the final normalized minimum, medium, and maximum duty ratios Dmin1, Dmid1, and Dmax1 are calculated by adding "1-Dmax1" to the normalized minimum, medium, and maximum duty ratios Dmin1, Dmid1, and Dmax1 so that the calculated normalized maximum duty ratio Dmax1 becomes 1. The calculated final normalized minimum, medium, and maximum duty ratios Dmin1, Dmid1, and Dmax1 are used in step S17.

[0124] After completing the process of step S15, the process proceeds to step S51, where the second modulation unit 87 calculates the normalized minimum, medium, and maximum duty ratios Dmin2, Dmid2, and Dmax2 in the same manner as step S16 in Fig. 11. Here, the final normalized minimum, medium, and maximum duty ratios Dmin2, Dmid2, and Dmax2 are calculated by adding "1-Dmax2" to the normalized minimum, medium, and maximum duty ratios Dmin2, Dmid2, and Dmax2 so that the calculated normalized maximum duty ratio Dmax2 becomes 1. The calculated final normalized minimum, medium, and maximum duty ratios Dmin2, Dmid2, and Dmax2 are used in step S17.

[0125] According to the present embodiment described above, the only reactive voltage vector that appears in each switching period is the seventh voltage vector V7, thereby achieving the same effects as those of the second embodiment.

[0126] Fourth Embodiment A fourth embodiment will be described below with reference to the drawings, focusing on differences from the first embodiment. In this embodiment, the angle between the output voltage vectors of the first and second inverters 20, 30 is changed from 120° to 180°.

[0127] A method for calculating the shift amount ΔD for reducing the ripple component of the zero-phase current will be described below.

[0128] First, a case where the first command vector Vinv1 is present in an odd-numbered sector will be described. Hereinafter, a case where the first command vector Vinv1 is present in the first sector will be described as an example with reference to FIG.

[0129] 17, "D1×V4" is the component of the second command vector Vinv2 in the direction in which the fourth voltage vector V4 extends. "D2×V5" is the component of the second command vector Vinv2 in the direction of the W-phase axis LW. In FIG. 17, the first command vector Vinv is set to a zero vector.

[0130] Next, a case where the zero-phase command voltage Vz* is set to a value other than 0 will be described. In FIG. 17, "D1×V4-ΔD×D1×V4" is a vector obtained by correcting "D1×V4" by "ΔD×D1×V4". "D2×V5-ΔD×D2×V5" is a vector obtained by correcting "D2×V5" by "ΔD×D2×V5". As a result, the second command vector Vinv2 becomes the second correction vector Vm2 as shown in FIG. 18.

[0131] 17 , the resultant vector of "ΔD×D2×V5" acting on the second command vector Vinv2 and "ΔD×D2×V2" acting in the direction in which the second voltage vector V2 extends is a zero vector. Also, the resultant vector of "ΔD×D1×V4" acting on the second command vector Vinv2 and "ΔD×D1×V1" acting in the direction of the U-phase axis LU is a zero vector. The resultant vector of "ΔD×D2×V2" acting in the direction in which the second voltage vector V2 extends and "ΔD×D1×V1" acting in the direction of the U-phase axis LU is a first correction vector Vm1 obtained by correcting the first command vector Vinv1, as shown in FIG.

[0132] The resultant vector of the first and second correction vectors Vm1 and Vm2 is the command voltage vector Vtr determined based on the command torque Trq*. The command voltage vector Vtr is expressed by the following equation (eq25).

[0133] When the corresponding zero-phase voltages are substituted for V1 and V2 in the above equation (eq25), the following equation (eq26) is derived.

[0134] That is, when the control device 70 determines that the first command vector Vinv1 exists in an odd-numbered sector, it calculates the shift amount ΔD expressed by the following equation (eq27) based on the power supply voltage VB and the zero-phase command voltage Vz*.

[0135] Next, a case where the first command vector Vinv1 is present in an even-numbered sector will be described. In the following, a case where the first command vector Vinv1 is present in the second sector will be described as an example.

[0136] 19, like FIG. 18, shows the first and second correction vectors Vm1 and Vm2 after the zero-phase sequence voltage is applied.

[0137] "(1-ΔD)×D1×V5" is the component of the second correction vector Vm2 in the direction in which the fifth voltage vector V5 extends. "(1-ΔD)×D2×V6" is the component of the second correction vector Vm2 in the direction in which the sixth voltage vector V6 extends. "ΔD×D1×V2" is the component of the first correction vector Vm1 in the direction in which the second voltage vector V2 extends. "ΔD×D2×V3" is the component of the first correction vector Vm1 in the direction of the V-phase axis LV.

[0138] The command voltage vector Vtr is expressed by the following equation (eq28).

[0139] When the corresponding zero-phase sequence voltages are substituted for V2 and V6 in the above equation (eq28), the following equation (eq29) is derived.

[0140] That is, when the control device 70 determines that the first command vector Vinv1 is present in the even sector, it calculates the shift amount ΔD expressed by the following equation (eq30) based on the power supply voltage VB and the zero-phase command voltage Vz*.

[0141] FIG. 20 is a block diagram showing the control process of the rotating electrical machine 40 executed by the control device 70.

[0142] The vector adjuster 88 calculates a zero-phase-sequence coefficient k based on the electrical angle θr, the power supply voltage VB, the zero-phase-sequence command voltage Vz*, and the d- and q-axis command voltages Vd* and Vq*.

[0143] The first modulator 86 generates drive signals for the switches SUHa to SWLa of the first inverter 20 based on the input electrical angle θr, power supply voltage VB, d- and q-axis command voltages Vd* and Vq*, and shift amount ΔD. The second modulator 87 generates drive signals for the switches SUHb to SWLb of the second inverter 30 based on the input electrical angle θr, power supply voltage VB, d- and q-axis command voltages Vd* and Vq*, and shift amount ΔD. In this embodiment, the vector adjuster 88, the first modulator 86, and the second modulator 87 correspond to a "switch control unit."

[0144] 21 is a flowchart of the control process for the rotary electric machine 40 executed by the control device 70. This process is repeatedly executed at a predetermined control cycle, for example.

[0145] In step S60, the vector adjuster 88 determines whether the first command vector Vinv1 of the first inverter 20 is in any of the first to sixth sectors. An example of the determination method will be described below.

[0146] First, the angle θvt1 formed by the U-phase axis LU and the first command vector Vinv1 is calculated using the following equation (eq31) based on the d-axis and q-axis command voltages Vd* and Vq* and the electrical angle θr.

[0147] Next, as shown in the above equation (eq13), if it is determined that the remainder when the calculated angle θvt1 is divided by 2π / 3 is equal to or less than π / 3, it is determined that the first command vector Vinv1 is in an odd sector.

[0148] On the other hand, as shown in the above equation (eq14), if it is determined that the remainder when the calculated angle θvt1 is divided by 2π / 3 is less than π / 3, it is determined that the first command vector Vinv1 is in an even sector.

[0149] In step S61, the first and second coefficients D1 and D2 are calculated based on the power supply voltage VB, the electrical angle θr, and the d-axis and q-axis command voltages Vd* and Vq* using the following equation (eq32).

[0150] In step S62, it is determined whether the sector identified in step S60 is an odd sector or an even sector. If it is determined in step S62 that the sector is an odd sector, the process proceeds to step S63. In step S63, the vector adjuster 88 calculates the shift amount ΔD using the above equation (eq27) based on the first and second coefficients D1 and D2, the power supply voltage VB, and the zero-phase command voltage Vz* calculated in step S61. On the other hand, if it is determined in step S62 that the sector is an even sector, the process proceeds to step S64. In step S64, the vector adjuster 88 calculates the shift amount ΔD using the above equation (eq30) based on the first and second coefficients D1 and D2, the power supply voltage VB, and the zero-phase command voltage Vz* calculated in step S61.

[0151] In step S65, the first modulation unit 86 calculates the first, second, and third duty ratios Da1, Db1, and Dc1 using the following equation (eq33) based on the shift amount ΔD, the electrical angle θr, the d-axis and q-axis command voltages Vd* and Vq*, and the power supply voltage VB calculated in step S63 or S64.

[0152] Thereafter, the first modulation unit 86 selects the smallest value of the calculated first, second, and third duty ratios Da1, Db1, and Dc1 as the minimum duty ratio Dk1min. Thereafter, the first modulation unit 86 calculates first U-, V-, and W-phase duty ratios Du1, Dv1, and Dw1 using the following equation (eq34) based on the calculated first, second, and third duty ratios Da1, Db1, and Dc1 and the selected minimum duty ratio Dk1min.

[0153] In step S66, the second modulation unit 87 calculates the first, second, and third duty ratios Da2, Db2, and Dc2 using the following equation (eq35) based on the shift amount ΔD, the electrical angle θr, the d-axis and q-axis command voltages Vd* and Vq*, and the power supply voltage VB calculated in step S63 or S64.

[0154] Thereafter, the second modulation unit 87 selects the smallest value of the calculated first, second, and third duty ratios Da2, Db2, and Dc2 as the minimum duty ratio Dk2min. Thereafter, the second modulation unit 87 calculates second U-, V-, and W-phase duty ratios Du2, Dv2, and Dw2 using the following equation (eq36) based on the calculated first, second, and third duty ratios Da2, Db2, and Dc2 and the selected minimum duty ratio Dk2min.

[0155] In step S67, the first modulation unit 86 generates drive signals for each switch SUHa to SWLa of the first inverter 20 based on a comparison of the magnitudes of the first U, V, and W phase duty ratios Du1, Dv1, and Dw1 calculated in step S65 with the carrier signal Sg.

[0156] In addition, in step S67, the second modulation unit 87 generates drive signals for each switch SUHb to SWLb of the second inverter 30 based on a comparison of the magnitude between the second U, V, and W phase duty ratios Du2, Dv2, and Dw2 calculated in step S66 and the carrier signal Sg.

[0157] According to the present embodiment described above, the torque of the rotary electric machine 40 can be maintained at the command torque Trq* while reducing the ripple component of the zero-phase current.

[0158] 22 and 23 show the transitions of the α-axis voltages Vα and Vβ of the respective phase windings 51U, 51V, and 51W in the present embodiment and the first embodiment. In FIGS. 22 and 23, a scale corresponding to the carrier signal Sg is shown on the left side, and a scale corresponding to the α-axis voltages Vα and Vβ is shown on the right side. The scale on the right side indicates the relative magnitude relationship of the α-axis voltages Vα and Vβ. In the present embodiment, the number of times the α-axis voltages Vα and Vβ fluctuate in one switching period is greater than in the first embodiment. This increases the frequency of the current flowing through the respective phase windings 51U, 51V, and 51W, thereby reducing the ripple component contained in this high-frequency current.

[0159] Other Embodiments The above embodiment may be modified as follows.

[0160] - Provided that the resultant vector of the effective voltage vector of the output voltage vector of the first inverter 20 corresponding to the zero-phase command voltage Vz* and the effective voltage vector of the output voltage vector of the second inverter 30 corresponding to the zero-phase command voltage Vz* is a zero vector, the angle between the output voltage vector of the first inverter 20 and the output voltage vector of the second inverter 30 may be an angle other than 120° or 180°.

[0161] The DC power source is not limited to a battery, and may be, for example, a fuel cell.

[0162] The rotating electric machine is not limited to a permanent magnet field type synchronous machine, and may be, for example, an induction machine.

[0163] 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.

[0164] 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.

[0165] The control unit and method described herein may be implemented by a special-purpose computer configured by configuring a processor and memory programmed to perform one or more functions embodied in a computer program. Alternatively, the control unit and method described herein may be implemented by a special-purpose computer configured by configuring a processor with one or more dedicated hardware logic circuits. Alternatively, the control unit and method described herein may be implemented by one or more special-purpose computers configured by combining a processor and memory programmed to perform one or more functions with 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 executed by a computer.

[0166] - The following describes characteristic configurations extracted from the above-described embodiments. [Configuration 1] A control device (70) for a rotating electric machine applied to a system including: a rotating electric machine (40) having a three-phase armature winding (51U to 51W), a first inverter (20) having first upper arm switches (SUHa to SWHa) and first lower arm switches (SULa to SWLa) connected in series for the same number of phases, and a series-connected assembly of the first upper arm switches and the first lower arm switches connected in parallel to a DC power source (10), and a second inverter (30) having second upper arm switches (SUHb to SWHb) and second lower arm switches (SULb to SWLb) connected in series for the same number of phases, wherein, in each phase, a low potential side terminal of the first upper arm switch and a high potential side terminal of the first lower arm switch are electrically connected to a first end of the armature winding, a command voltage calculation unit (82) that calculates d- and q-axis main command voltages (Vdm, Vqm) that are command values ​​of d- and q-axis voltages to be applied to the armature winding; and switch control units (83-88) that perform switching control of the first upper arm switch, the first lower arm switch, the second upper arm switch, and the second lower arm switch so as to satisfy a condition that the d- and q-axis voltages to be applied to the armature winding are set to the zero-phase sequence command voltages (Vz*) while maintaining the d- and q-axis voltages to be applied to the armature winding at the calculated d- and q-axis main command voltages. A control device for a rotating electric machine comprising:[Configuration 2] The control device for a rotary electric machine according to Configuration 1, wherein the command voltage calculation unit calculates d- and q-axis command voltages (Vd*, Vq*) for the first and second inverters to make the d- and q-axis voltages applied to the armature windings equal to the calculated d- and q-axis main command voltages, and the switch control unit performs the switching control based on the calculated d- and q-axis command voltages for the first and second inverters so that two effective voltage vectors sandwiching an output voltage vector of the first inverter in a d-q coordinate system, the effective voltage vectors having a phase difference of 60°, and two effective voltage vectors sandwiching an output voltage vector of the second inverter in a d-q coordinate system, the effective voltage vectors having a phase difference of 60°, appear in every switching period. [Configuration 3] The control device for a rotating electric machine according to Configuration 1 or 2, wherein the switch control unit (83 to 87) performs the switching control so that a composite vector of an effective voltage vector corresponding to the zero-phase sequence command voltage among output voltage vectors of the first inverter determined based on the calculated d- and q-axis main command voltages and the zero-phase sequence command voltages, and an effective voltage vector corresponding to the zero-phase sequence command voltage among output voltage vectors of the second inverter determined based on the calculated d- and q-axis main command voltages and the zero-phase sequence command voltages, becomes a zero vector. [Configuration 4] The control device for a rotating electric machine according to Configuration 2 or 3, wherein the switch control unit performs the switching control so that a phase difference between the output voltage vector of the first inverter determined based on the calculated d- and q-axis command voltages for the first inverter and the output voltage vector of the second inverter determined based on the calculated d- and q-axis command voltages for the second inverter becomes 120°. [Configuration 5] The control device for a rotating electric machine according to Configuration 4, wherein six sectors are defined by six effective voltage vectors each shifted by a phase difference of 60°, and the switch control unit switches the positive and negative sides of the zero-phase command voltage while maintaining the same magnitude of the zero-phase command voltage based on which of the six sectors contains the output voltage vector of the first inverter.[Configuration 6] The control device for a rotary electric machine according to Configuration 4 or 5, wherein the switch control unit performs the switching control based on the calculated d-axis and q-axis command voltages for the first and second inverters so that two active voltage vectors sandwiching the output voltage vector of the first inverter and having a phase difference of 60°, two active voltage vectors sandwiching the output voltage vector of the second inverter and having a phase difference of 60°, a reactive voltage vector that turns off the first and second upper arm switches of each phase, and a reactive voltage vector that turns on the first and second upper arm switches of each phase appear in every switching period. [Configuration 7] The control device for a rotating electric machine according to Configuration 4 or 5, wherein the switch control unit performs the switching control based on the calculated d-axis and q-axis command voltages for the first and second inverters so that two active voltage vectors sandwiching the output voltage vector of the first inverter and having a phase difference of 60°, two active voltage vectors sandwiching the output voltage vector of the second inverter and having a phase difference of 60°, and a reactive voltage vector appear in every switching period, and the reactive voltage vectors are the reactive voltage vectors that turn off the first and second upper arm switches, out of the reactive voltage vector (V0) that turns off the first and second upper arm switches and the reactive voltage vector (V7) that turns on the first and second upper arm switches. [Configuration 8] The control device for a rotating electric machine according to Configuration 4 or 5, wherein the switch control unit performs the switching control based on the calculated d-axis and q-axis command voltages for the first and second inverters so that two active voltage vectors sandwiching the output voltage vector of the first inverter and having a phase difference of 60°, two active voltage vectors sandwiching the output voltage vector of the second inverter and having a phase difference of 60°, and a reactive voltage vector appear in every switching period, and the reactive voltage vectors are the reactive voltage vectors that turn on the first and second upper arm switches, out of the reactive voltage vector (V0) that turns off the first and second upper arm switches and the reactive voltage vector (V7) that turns on the first and second upper arm switches.

[0167] 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 control device (70) for a rotating electric machine that is applied to a system including: a rotating electric machine (40) having three-phase armature windings (51U to 51W); a first inverter (20) having first upper arm switches (SUHa to SWHa) and first lower arm switches (SULa to SWLa) connected in series for the number of phases, the series-connected first upper arm switches and the first lower arm switches being connected in parallel to a DC power source (10); and a second inverter (30) having second upper arm switches (SUHb to SWHb) and second lower arm switches (SULb to SWLb) connected in series for the number of phases, wherein, in each phase, a low potential side terminal of the first upper arm switch and a high potential side terminal of the first lower arm switch are electrically connected to a first end of the armature winding, a command voltage calculation unit (82) that calculates d- and q-axis main command voltages (Vdm, Vqm) that are command values ​​of d- and q-axis voltages to be applied to the armature winding; and switch control units (83-88) that perform switching control of the first upper arm switch, the first lower arm switch, the second upper arm switch, and the second lower arm switch so as to satisfy a condition that the d- and q-axis voltages to be applied to the armature winding are set to the zero-phase sequence command voltages (Vz*) while maintaining the d- and q-axis voltages to be applied to the armature winding at the calculated d- and q-axis main command voltages. A control device for a rotating electric machine comprising:

2. The control device for a rotating electric machine according to claim 1, wherein the command voltage calculation unit calculates d- and q-axis command voltages (Vd*, Vq*) for the first and second inverters to make the d- and q-axis voltages applied to the armature windings equal to the calculated d- and q-axis main command voltages, and the switch control unit performs the switching control based on the calculated d- and q-axis command voltages for the first and second inverters so that two effective voltage vectors, which sandwich the output voltage vector of the first inverter in a d-q coordinate system and have a phase difference of 60°, and two effective voltage vectors, which sandwich the output voltage vector of the second inverter in a d-q coordinate system and have a phase difference of 60°, appear in every switching period.

3. A control device for a rotating electric machine as described in claim 1 or 2, wherein the switch control unit (83 to 87) performs the switching control so that a composite vector of an effective voltage vector corresponding to the zero-phase command voltage among the output voltage vectors of the first inverter determined based on the calculated d- and q-axis main command voltages and the zero-phase command voltage, and an effective voltage vector corresponding to the zero-phase command voltage among the output voltage vectors of the second inverter determined based on the calculated d- and q-axis main command voltages and the zero-phase command voltage, becomes a zero vector.

4. A control device for a rotating electric machine as described in claim 3, wherein the switch control unit performs the switching control so that the phase difference between the output voltage vector of the first inverter determined based on the calculated d- and q-axis command voltages for the first inverter and the output voltage vector of the second inverter determined based on the calculated d- and q-axis command voltages for the second inverter is 120°.

5. A control device for a rotating electric machine as described in claim 4, wherein six sectors are defined by six effective voltage vectors each shifted by a phase difference of 60°, and the switch control unit switches the positive and negative sides of the zero-phase command voltage while maintaining the same magnitude of the zero-phase command voltage based on which of the six sectors contains the output voltage vector of the first inverter.

6. The control device for a rotating electric machine according to claim 4, wherein the switch control unit performs the switching control based on the calculated d-axis and q-axis command voltages for the first and second inverters so that two active voltage vectors sandwiching the output voltage vector of the first inverter and having a phase difference of 60°, two active voltage vectors sandwiching the output voltage vector of the second inverter and having a phase difference of 60°, reactive voltage vectors that turn off the first and second upper arm switches of each phase, and reactive voltage vectors that turn on the first and second upper arm switches of each phase appear in each switching period.

7. The control device for a rotating electric machine according to claim 4, wherein the switch control unit performs the switching control based on the calculated d-axis and q-axis command voltages for the first and second inverters so that two active voltage vectors sandwiching the output voltage vector of the first inverter and having a phase difference of 60°, two active voltage vectors sandwiching the output voltage vector of the second inverter and having a phase difference of 60°, and a reactive voltage vector appear in every switching period, and the reactive voltage vectors are the reactive voltage vectors that cause the first and second upper arm switches to be turned off, out of the reactive voltage vector (V0) that causes the first and second upper arm switches to be turned off and the reactive voltage vector (V7) that causes the first and second upper arm switches to be turned on.

8. The control device for a rotating electric machine according to claim 4, wherein the switch control unit performs the switching control based on the calculated d-axis and q-axis command voltages for the first and second inverters so that two active voltage vectors sandwiching the output voltage vector of the first inverter and having a phase difference of 60°, two active voltage vectors sandwiching the output voltage vector of the second inverter and having a phase difference of 60°, and a reactive voltage vector appear in every switching period, and the reactive voltage vectors are the reactive voltage vectors that turn on the first and second upper arm switches out of the reactive voltage vector (V0) that turns off the first and second upper arm switches and the reactive voltage vector (V7) that turns on the first and second upper arm switches.

9. A control device for a rotating electric machine as described in claim 3, wherein the switch control unit performs the switching control so that the phase difference between the output voltage vector of the first inverter, which is determined based on the calculated d- and q-axis command voltages for the first inverter, and the output voltage vector of the second inverter, which is determined based on the calculated d- and q-axis command voltages for the second inverter, is 180°.

10. A program applied to a system including: a rotating electric machine (40) having three-phase armature windings (51U to 51W); a first inverter (20) having first upper arm switches (SUHa to SWHa) and first lower arm switches (SULa to SWLa) connected in series for the same number of phases, the series-connected first upper arm switches and the first lower arm switches being connected in parallel to a DC power source (10); and a second inverter (30) having second upper arm switches (SUHb to SWHb) and second lower arm switches (SULb to SWLb) connected in series for the same number of phases, wherein, in each phase, a low potential side terminal of the first upper arm switch and a high potential side terminal of the first lower arm switch are electrically connected to a first end of the armature winding; In each phase, a low potential side terminal of the second upper arm switch and a high potential side terminal of the second lower arm switch are electrically connected to a second end of the armature winding, 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 are electrically connected, 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 are electrically connected, and a processor (71) is configured to perform: a command voltage calculation process for calculating d- and q-axis main command voltages (Vdm, Vqm) which are command values ​​of d- and q-axis voltages to be applied to the armature winding; and a switch control process for performing switching control of the first upper arm switch, the first lower arm switch, the second upper arm switch, and the second lower arm switch so as to satisfy a condition that the d- and q-axis voltages to be applied to the armature winding are set to the zero-phase sequence command voltage (Vz*) while maintaining the d- and q-axis voltages to be applied to the armature winding at the calculated d- and q-axis main command voltages. A program that executes.

11. A method for controlling a rotating electric machine applied to a system including: a rotating electric machine (40) having three-phase armature windings (51U to 51W); a first inverter (20) having first upper arm switches (SUHa to SWHa) and first lower arm switches (SULa to SWLa) connected in series for the number of phases, the series-connected first upper arm switches and the first lower arm switches being connected in parallel to a DC power source (10); and a second inverter (30) having second upper arm switches (SUHb to SWHb) and second lower arm switches (SULb to SWLb) connected in series for the number of phases, wherein, in each phase, a low potential side terminal of the first upper arm switch and a high potential side terminal of the first lower arm switch are electrically connected to a first end of the armature winding; a low potential side terminal of the second upper arm switch and a high potential side terminal of the second lower arm switch are electrically connected to a second end of the armature winding 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 are electrically connected in each phase, and a low potential side terminal of the first lower arm switch and a low potential side terminal of the second lower arm switch are electrically connected in each phase, and a command voltage calculation step of calculating d- and q-axis main command voltages (Vdm, Vqm) which are command values ​​of d- and q-axis voltages to be applied to the armature winding, and a switch control step of performing switching control of the first upper arm switch, the first lower arm switch, the second upper arm switch, and the second lower arm switch so as to satisfy a condition that the zero-phase sequence voltage to be applied to the armature winding is set to a zero-phase sequence command voltage (Vz*) while maintaining the d- and q-axis voltages to be applied to the armature winding at the calculated d- and q-axis main command voltages.

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