Control device for rotary electrical machine, program, and method for controlling rotary electrical machine

Abstract

A control device (70) for a rotary electrical machine is applied to a system comprising: a rotary electrical machine (40); a first inverter (20); a second inverter (30); a positive electrode-side bus (11); a negative electrode-side bus (12); and a changeover switch (13, 17) that is provided to a bus of interest which is at least one of the positive electrode-side bus and the negative electrode-side bus. The control device sets the control modes of first upper arm switches (SUHa to SWHa) and first lower arm switches (SULa to SWLa) of the first inverter and the control modes of second upper arm switches (SUHb to SWHb) and second lower arm switches (SULb to SWLb) of the second inverter. The control device selects Y drive control or H drive control as the control mode. Prior to switching the control mode from the Y drive control to the H drive control, the control device performs charging control to alternately turn on the set of second upper arm switches and the set of second lower arm switches in the Y drive control.

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. 2023-219449, filed on December 26, 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 the drive of a rotating electric machine using two inverters has been known. In this system, a first inverter is electrically connected to first ends of a multi-phase armature winding of the rotating electric machine, and a second inverter is electrically connected to second ends of the armature winding. Drive control of the rotating electric machine is performed by switching control of the first and second inverters, thereby achieving high output and high efficiency of the system. An example of such a technology is disclosed in Patent Document 1.

[0004] Japanese Patent Application Laid-Open No. 2017-175747

[0005] In the above system, a capacitor may be connected to the second inverter, and in this case, an overcurrent may flow in the system when the control mode of each switch is changed.

[0006] The main object of the present disclosure is to provide a control device, program, and control method for a rotating electric machine that can prevent an overcurrent from flowing within the system when the control mode of each switch is switched.

[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 armature winding; a first inverter having first upper arm switches and first lower arm switches connected in series for the same number of phases, and a series connection of the first upper arm switches and the first lower arm switches connected in parallel to a DC power source; a second inverter having second upper arm switches and second lower arm switches connected in series for the same number of phases; a capacitor connected in parallel to the series connection of the second upper arm switches and the second lower arm switches; 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; 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 a changeover switch provided on a target bus bar that is at least one of the positive bus bar and the negative bus bar, 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, the changeover switch electrically connects the first inverter and the second inverter via the target bus when turned on, and cuts off the electrical connection between the first inverter and the second inverter via the target bus when turned off, the power supply comprises: a selection unit that selects a control mode of the first upper arm switch, the first lower arm switch, the second upper arm switch, and the second lower arm switch; and a switch control unit that controls the on or off of the first upper arm switch, the first lower arm switch, the second upper arm switch, and the second lower arm switch based on the selected control mode.

[0008] The selection unit selects Y drive control or H drive control as the control mode based on the operating point of the rotating electric machine, the Y drive control is a control in which the second upper arm switch of each phase is fixed on and the second lower arm switch of each phase is fixed off when the changeover switch is off, or the second lower arm switch of each phase is fixed on and the second upper arm switch of each phase is fixed off when the changeover switch is off, and the first upper arm switch and the first lower arm switch are PWM driven, the H drive control is a control in which the first upper arm switch, the first lower arm switch, the second upper arm switch, and the second lower arm switch are PWM driven, and prior to switching the control mode from the Y drive control to the H drive control, the switch control unit performs charging control in the Y drive control in which the set of second upper arm switches of each phase and the set of second lower arm switches of each phase are alternately turned on.

[0009] The control device switches between Y-drive control and H-drive control as the control mode of each switch based on the operating point of the rotating electric machine. Here, a capacitor may be connected in parallel to the series connection of the second upper arm switch and the second lower arm switch that make up the system. The voltage applied to the capacitor differs when Y-drive control is performed and when H-drive control is performed.

[0010] In the H drive control, the DC power supply and the capacitor are connected via the positive bus. Therefore, the power supply voltage of the DC power supply is applied to the capacitor. In the Y drive control, the voltage of the capacitor is lower than the power supply voltage of the DC power supply. Therefore, when switching from the Y drive control to the H drive control and the power supply voltage of the DC power supply is applied to the capacitor, there is a concern that an overcurrent may flow.

[0011] Here, in Y-drive control, a zero-phase current may flow through the armature winding of each phase. In consideration of this, the switch control unit of the present disclosure performs charging control in Y-drive control, prior to switching the control mode from Y-drive control to H-drive control, by alternately turning on the second set of upper arm switches for each phase and the second set of lower arm switches for each phase. This allows the voltage applied to the capacitor by the armature winding and the second inverter to be boosted and the capacitor to be charged when the first upper arm switch and the first lower arm switch are PWM-driven. This makes it possible to prevent an overcurrent from flowing in the system when the control mode of each switch is subsequently switched from Y-drive control to H-drive control.

[0012] 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 one embodiment, Fig. 2 is a functional block diagram of control processing executed by a control device, Fig. 3 is a diagram showing areas of Y and H drive control, Fig. 4 is a diagram showing a control mode of H drive control, Fig. 5 is a diagram showing a control mode of Y drive control, Fig. 6 is a diagram showing a control mode of Y drive control, and Fig. 7 is a flowchart of control processing executed by the control device.

[0013] Hereinafter, an embodiment of a control device according to the present disclosure will be described with reference to the drawings. The control device of this embodiment is applied to a control system mounted on an electrically powered vehicle such as an electric vehicle or a hybrid vehicle.

[0014] 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.

[0015] 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 .

[0016] 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.

[0017] 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.

[0018] 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 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 of each phase and the emitters of the second lower arm switches SULb, SVLb, SWLb of each phase are connected via a negative bus 12, which is an electrical path such as a bus bar.

[0019] 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 positive bus 11 and the positive terminal of the battery 10. When the power switch 14 is turned on, the positive terminal of the battery 10 is electrically connected to the collectors of the first upper arm switches SUHa, SVHa, and SWHa of each phase. When the power switch 14 is turned off, the positive terminal of the battery 10 is electrically disconnected from the collectors of the first upper arm switches SUHa, SVHa, and SWHa of each phase.

[0020] The control system 100 includes first and second capacitors 15 and 16. The first and second capacitors 15 and 16 function as smoothing capacitors. The first capacitor 15 is connected in parallel to the series connection of the first upper arm switches SUHa to SWHa of each phase and the first lower arm switches SULa to SWLa of each phase. The second capacitor 16 is connected in parallel to the series connection of the second upper arm switches SUHb to SWHb of each phase and the second lower arm switches SULb to SWLb of each phase.

[0021] 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.

[0022] 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.

[0023] 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.

[0024] The control system 100 includes first and second changeover switches 13 and 17. The first changeover switch 13 is provided on the positive bus 11 (corresponding to the "target bus"). The first changeover switch 13 is, for example, a semiconductor switching element or a mechanical relay. When turned on, the first changeover switch 13 electrically connects the collectors of the upper phase arm switches SUHa, SVHa, and SWHa of the first inverter 20 to the collectors of the upper phase arm switches SUHb, SVHb, and SWHb of the second inverter 30. When turned off, the first changeover switch 13 electrically disconnects the collectors of the upper phase arm switches SUHa, SVHa, and SWHa of the first inverter 20 from the collectors of the upper phase arm switches SUHb, SVHb, and SWHb of the second inverter 30.

[0025] The second changeover switch 17 is provided on the negative bus 12 (corresponding to the "target bus"). The second changeover switch 17 is, for example, a semiconductor switching element or a mechanical relay. When turned on, the second changeover switch 17 electrically connects the emitters of the lower phase arm switches SULa, SVLa, and SWLa of the first inverter 20 to the emitters of the lower phase arm switches SULb, SVLb, and SWLb of the second inverter 30. When turned off, the second changeover switch 17 electrically disconnects the emitters of the lower phase arm switches SULa, SVLa, and SWLa of the first inverter 20 from the emitters of the lower phase arm switches SULb, SVLb, and SWLb of the second inverter 30.

[0026] The first and second changeover switches 13 and 17 may be, for example, IGBTs. In this case, freewheel diodes are connected in anti-parallel to the first and second changeover switches 13 and 17. When the first changeover switch 13 is an IGBT, the collector of the IGBT is connected to the first inverter 20 side, and the emitter of the IGBT is connected to the second inverter 30 side. When the second changeover switch 17 is an IGBT, the collector of the IGBT is connected to the second inverter 30 side, and the emitter of the IGBT is connected to the first inverter 20 side.

[0027] Returning to the explanation of FIG. 1, the control system 100 includes a current sensor 60 , a rotation angle sensor 61 , and a voltage sensor 62 .

[0028] The current sensor 60 detects the phase current flowing through each of the phase windings 51U, 51V, and 51W. In this embodiment, the current sensor 60 is provided at one of the ends of each of the phase windings 51U, 51V, and 51W that is closer to the first inverter 20. Hereinafter, the sign of the phase current is defined as positive when the current flows from the first terminal 51Ua, 51Va, and 51Wa of each of the windings 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 60 may also be provided at one of the ends of each of the phase windings 51U, 51V, and 51W that is closer to the second inverter 30.

[0029] 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 first capacitor 15.

[0030] 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.

[0031] 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 7, which will be described later.

[0032] 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.

[0033] In order to control the control variable of the rotary electric machine 40 to a command value, the control device 70 controls the on / off of the first and second changeover switches 13 and 17, the switches SUHa to SWLa of the first inverter 20, and the switches SUHb to SWLb of the second inverter 30 while the power switch 14 is on. In this embodiment, the control variable is torque.

[0034] 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.

[0035] The command value calculation unit 80 calculates a d-axis current command value Id* and a q-axis current command value Iq* in the dq coordinate system based on the command torque Trq* received from a higher-level control device than the control device 70 .

[0036] The two-phase conversion unit 81 calculates the d-axis current value Idr and the q-axis current value 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.

[0037] The current feedback unit 82 calculates a d-axis voltage command value Vd* and a q-axis voltage command value Vq* based on the d- and q-axis current command values ​​Id* and Iq* and the d- and q-axis current values ​​Idr and Iqr. Specifically, the current feedback unit 82 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 82 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 is, for example, proportional-plus-integral control.

[0038] The three-phase converter 83 calculates U-, V-, and W-phase voltage command values ​​Vu*, Vv*, and Vw* based on the d- and q-axis voltage command values ​​Vd*, Vq* and the electrical angle θr. The U-, V-, and W-phase voltage command values ​​Vu*, Vv*, and Vw* are command values ​​for voltages applied to the U-, V-, and W-phase windings 51U, 51V, and 51W. The U-, V-, and W-phase voltage command values ​​Vu*, Vv*, and Vw* are shifted in phase by 120° in electrical angle. In this embodiment, the sign of the applied voltage to each phase winding is positive when the potential at the first terminal 51Ua, 51Va, 51Wa of the windings 51U, 51V, 51W is higher than the potential at the second terminal 51Ub, 51Vb, 51Wb, and negative when the potential at the second terminal 51Ub, 51Vb, 51Wb of the windings 51U, 51V, 51W is higher than the potential at the first terminal 51Ua, 51Va, 51Wa.

[0039] The speed calculation unit 84 calculates the rotation speed Nr of the rotor 41 based on the electrical angle θr.

[0040] The selection unit 85 selects whether the drive state of the control system 100 should be Y drive control or H drive control. In the present embodiment, the selection unit 85 selects whether the drive state should be Y drive control or H drive control based on the operating point of the rotating electric machine 40 determined by the calculated rotation speed Nr and command torque Trq* and on the control map information.

[0041] 3 shows an example of the control map information. The control map information is information that defines the Y drive control region and the H drive control region in association with the rotation speed Nr and the command torque Trq*. The control map information is stored in the storage unit 72.

[0042] The selection unit 85 selects Y drive control when it determines that the rotation speed Nr is equal to or less than the determination threshold Jth. On the other hand, the selection unit 85 selects H drive control when it determines that the rotation speed Nr is higher than the determination threshold Jth or when it determines that the rotation speed Nr has exceeded a predetermined speed Nth. The determination threshold Jth increases as the command torque Trq* decreases in the region where the rotation speed Nr is equal to or less than the predetermined speed Nth.

[0043] Returning to the explanation of FIG. 2, the switch control unit 86 generates a carrier signal for generating drive signals for the switches SUHa-SWLa and SUHb-SWLb of the first and second inverters 20, 30. In this embodiment, the carrier signal is a triangular wave signal with equal increasing and decreasing speeds. The drive signals are comprised of switch on and off commands.

[0044] The switch control unit 86 generates drive signals for the switches SUHa to SWLa and SUHb to SWLb of the first and second inverters 20 and 30 based on the U-, V-, and W-phase voltage command values ​​Vu*, Vv*, and Vw*, the power supply voltage Vsr, which is the voltage detected by the voltage sensor 62, and the generated carrier signal.

[0045] Specifically, the switch control unit 86 calculates U-, V-, and W-phase normalized command values ​​Dutyu, Dutyv, and Dutyw by normalizing the U-, V-, and W-phase voltage command values ​​Vu*, Vv*, and Vw* by the power supply voltage Vsr. Specifically, the U-, V-, and W-phase normalized command values ​​Dutyu, Dutyv, and Dutyw are values ​​obtained by dividing the U-, V-, and W-phase voltage command values ​​Vu*, Vv*, and Vw* by half the power supply voltage Vsr.

[0046] 4, the switch control unit 86 performs H drive control by turning on the first and second changeover switches 13 and 17 to PWM-drive the switches SUHa to SWLa of the first inverter 20 and PWM-drive the switches SUHb to SWLb of the second inverter 30. The switch control unit 86 generates drive signals for the switches SUHa to SWLa and SUHb to SWLb of the first and second inverters 20 and 30 based on a comparison of the magnitudes of the U-, V-, and W-phase normalized command values ​​Dutyu, Dutyv, and Dutyw with the carrier signal.

[0047] On the other hand, when the selection unit 85 selects the Y drive control, the switch control unit 86 executes the Y drive control. More specifically, in the Y drive control, the switch control unit 86 turns off the first and second changeover switches 13 and 17 and performs control to PWM drive the switches SUHa to SWLa of the first inverter 20. In addition, in the second inverter 30, either one of the following is executed: control to fix the upper arm switches SUHb, SVHb, and SWHb of each phase on and fix the lower arm switches SULb, SVLb, and SWLb of each phase off, as shown in Fig. 5, or control to fix the upper arm switches SUHb, SVHb, and SWHb of each phase off and fix the lower arm switches SULb, SVLb, and SWLb of each phase on, as shown in Fig. 6.

[0048] 5 or 6, the phase windings 51U, 51V, 51W are star-connected via the second inverter 30. The switch control unit 86 generates drive signals for the switches SUHa to SWLa of the first inverter 20 based on a comparison of the magnitudes of the U-, V-, and W-phase normalized command values ​​Dutyu, Dutyv, and Dutyw with the carrier signal.

[0049] Based on the generated drive signal, the switch control unit 86 controls the charge / discharge current of the gates of the switches SUHa-SWLa and SUHb-SWLb of the first and second inverters 20 and 30. As a result, the on / off of the switches SUHa-SWLa and SUHb-SWLb of the first and second inverters 20 and 30 is controlled in accordance with the drive signal.

[0050] In this embodiment, during execution of the Y drive control, the switch control unit 86 executes charging control of the second capacitor 16 before switching the control mode of each switch to the H drive control.

[0051] 7 shows a flowchart of the control process of the rotary electric machine 40 executed by the control device 70. The process shown in FIG. 7 is repeatedly executed by the processor 71 of the control device 70, for example, at a predetermined control cycle.

[0052] In step S10, it is determined whether the control state of each switch designated by the selection unit 85 is the Y drive state or the H drive state. If it is determined in step S10 that the control state of each switch is the H drive state, the process proceeds to step S14, where H drive control is performed.

[0053] On the other hand, if it is determined in step S10 that the control state of each switch is the Y drive state, the process proceeds to step S11, where the command torque Trq* is acquired. Also, the speed calculation unit 84 calculates the rotation speed Nr.

[0054] In step S12, it is determined whether or not the situation calls for the execution of charging control. In this embodiment, as shown in FIG. 3, if it is determined that the rotation speed Nr is equal to or greater than the switching threshold Cth, it is determined that the situation calls for the execution of charging control. The switching threshold Cth is a value smaller than the determination threshold Jth. The switching threshold Cth increases as the command torque Trq* decreases. The switching threshold Cth is preferably set to a value between 70 and 90% of the determination threshold Jth, for example, and more preferably to a value between 80 and 90%.

[0055] If it is determined in step S12 that the situation is not one in which switching to charging control is necessary, the process proceeds to step S15, where Y drive control is performed.

[0056] If it is determined in step S12 that the situation requires switching to charging control, the process proceeds to step S13. In step S13, charging control is executed by alternately turning on the set of second upper arm switches SUHb, SVHb, and SWHb for each phase of the second inverter 30 and the set of second lower arm switches SULb, SVLb, and SWLb for each phase of the second inverter 30.

[0057] When the Y drive control is executed, the voltage across the second capacitor 16 is lower than when the H drive control is executed. For example, when the Y drive control is executed, the voltage across the second capacitor 16 is half the output voltage of the battery 10. Furthermore, when the H drive control is executed, the voltage across the second capacitor 16 is the output voltage of the battery 10. Therefore, when switching from the Y drive control to the H drive control, if the voltage difference across the second capacitor 16 before and after the switch is large, an overcurrent may flow from the battery 10 to the second capacitor 16.

[0058] When Y-phase drive control is executed, a zero-phase current may flow through the U-phase winding 51U, the V-phase winding 51V, and the W-phase winding 51W. Execution of charging control boosts the voltage applied to the second capacitor 16. This is because, during charging control, the U-phase winding 51U, the V-phase winding 51V, and the W-phase winding 51W, together with the second inverter 30, function as a boost converter. Specifically, current flows from the upper arm of the first inverter 20 to the lower arm of the second inverter 30 via the U-phase winding 51U, the V-phase winding 51V, and the W-phase winding 51W, storing magnetic energy in the armature winding. Current also flows from the U-phase winding 51U, the V-phase winding 51V, and the W-phase winding 51W to the upper arm of the second inverter 30, releasing the magnetic energy stored in the armature winding. This cycle repeats. This charges the second capacitor 16.

[0059] Furthermore, since the set of upper arm switches SUHb, SVHb, and SWHb of the second inverter 30 and the set of lower arm switches SULb, SVLb, and SWLb of the second inverter 30 are alternately turned on, the second inverter 30 functions as a neutral point in the charge control, thereby suppressing the effect of the charge control on the torque controllability in the Y-drive control.

[0060] The control device 70 may set the charging voltage from the second inverter 30 to the second capacitor 16 during charging control based on the duty ratio of the second inverter 30. The duty ratio is expressed as "Ton / Ts." Ts is the switching period for turning on the set of upper arm switches SUHb, SVHb, and SWHb of each phase and the set of lower arm switches SULb, SVLb, and SWLb of each phase. Ton is the on period of the lower arm switches SULb, SVLb, and SWLb of each phase within the switching period Ts. The larger the duty ratio, the higher the charging voltage. The control device 70 may, for example, set the duty ratio so that the charging voltage becomes the voltage detected by the voltage sensor 62.

[0061] If the charge control is executed in the current control cycle, the control device 70 may not execute the charge control before the control mode of each switch is switched from the Y drive state to the H drive control in the next control cycle, for example. This is because the second capacitor 16 is charged in the current control cycle. The control device 70 may also execute the charge control every time a positive determination is made in step S12.

[0062] According to the present embodiment described above, it is possible to boost the voltage applied to the second capacitor 16. As a result, it is possible to reduce the difference between the terminal voltage of the second capacitor 16 and the output voltage of the battery 10 before switching from the Y drive control to the H drive control. Therefore, when switching to the H drive control thereafter, it is possible to prevent an overcurrent from flowing from the battery 10 to the second capacitor 16.

[0063] Other Embodiments The above embodiment may be modified as follows.

[0064] In the above embodiment, the control device 70 may perform PWM driving based on space vector modulation instead of PWM driving based on a magnitude comparison between the command value and the carrier signal.

[0065] The switching threshold Cth does not necessarily depend on the command torque Trq* as shown in FIG. 3 , but may be determined, for example, only by the rotation speed Nr. Specifically, the switching threshold Cth may be the same regardless of the magnitude of the command torque Trq*. More specifically, the switching threshold Cth may extend parallel to the axis of the command torque Trq* in FIG. 3 .

[0066] When Y drive control is selected by the selection unit 85 and the second upper arm switches SUHb, SVHb, and SWHb of each phase are fixed to ON and the second lower arm switches SULb, SVLb, and SWLb of each phase are fixed to OFF, as shown in FIG. 5, the switch control unit 86 may turn on the second changeover switch 17.

[0067] When the Y drive control is selected by the selector 85 and the second upper arm switches SUHb, SVHb, and SWHb of each phase are fixed to be off and the second lower arm switches SULb, SVLb, and SWLb of each phase are fixed to be on as shown in FIG. 6 , the switch control unit 86 may turn on the first changeover switch 13 (for example, an IGBT with a freewheel diode connected in reverse parallel).

[0068] The carrier signal is not limited to a triangular wave signal, but may be, for example, a sawtooth wave signal.

[0069] The DC power source is not limited to a battery, and may be, for example, a fuel cell.

[0070] The rotating electric machine is not limited to a permanent magnet field type synchronous machine, and may be, for example, an induction machine.

[0071] 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.

[0072] 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.

[0073] 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.

[0074] 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.

[0075] 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 electrical machine (40) having a multi-phase armature winding (51U to 51W), a first inverter (20) having a number of series-connected first upper arm switches (SUHa to SWHa) and first lower arm switches (SUL a to SWL a) corresponding to the number of phases, with the series connection of the first upper arm switches and the first lower arm switches being connected in parallel to a DC power supply (10), a second inverter (30) having a number of series-connected second upper arm switches (SUHb to SWHb) and second lower arm switches (SULb to SWLb) corresponding to the number of phases, a capacitor (16) connected in parallel to the series connection of the second upper arm switches and the second lower arm switches, a positive bus bar (11) electrically connecting the high potential side terminals of the first upper arm switches and the high potential side terminals of the second upper arm switches in each phase, a negative bus bar (12) electrically connecting the low potential side terminals of the first lower arm switches and the low potential side terminals of the second lower arm switches in each phase, and a switching switch (13, 17) provided on a target bus bar which is at least one of the positive bus bar and the negative bus bar. In a control device (70) of a rotating electrical machine applied to a system comprising: in each phase, the low potential side terminal of the first upper arm switch and the high potential side terminal of the first lower arm switch are electrically connected to the first end of the armature winding; in each phase, the low potential side terminal of the second upper arm switch and the high potential side terminal of the second lower arm switch are electrically connected to the second end of the armature winding; the switching switch, when turned on, electrically connects the first inverter and the second inverter via the target bus bar, and when turned off, cuts off the electrical connection between the first inverter and the second inverter via the target bus bar; a selection unit (85) for selecting a control mode of the first upper arm switch, the first lower arm switch, the second upper arm switch, and the second lower arm switch; and a switch control unit (86) for controlling the on or off of the first upper arm switch, the first lower arm switch, the second upper arm switch, and the second lower arm switch based on the selected control mode. The selection unit is configured to determine the operating point (Trq*,Based on Nr), as the control mode, Y drive control or H drive control is selected. The Y drive control is to keep the second upper arm switch of each phase on and fixed and the second lower arm switch of each phase off and fixed in the state where the switching switch is off, or to keep the second lower arm switch of each phase on and fixed and the second upper arm switch of each phase off and fixed in the state where the switching switch is off, and at the same time, PWM drive the first upper arm switch and the first lower arm switch. The H drive control is to PWM drive the first upper arm switch, the first lower arm switch, the second upper arm switch and the second lower arm switch. The switch control unit performs charging control to alternately turn on the set of the second upper arm switches of each phase and the set of the second lower arm switches of each phase in the Y drive control prior to switching the control mode from the Y drive control to the H drive control, a control device for a rotating electrical machine.

2. During the execution of the Y drive control, the switch control unit determines whether it is a situation where the charge control should be performed based on the operating point, and when it is determined that it is a situation where the charge control should be performed, the charge control is performed. The control device for a rotating electrical machine according to claim 1.

3. A rotating electrical machine (40) having a multi-phase armature winding (51U to 51W), a first inverter (20) having a number of series-connected first upper arm switches (SUHa to SWHa) and first lower arm switches (SUL a to SWL a) corresponding to the number of phases, with the series connection of the first upper arm switch and the first lower arm switch being connected in parallel to a DC power supply (10); a second inverter (30) having a number of series-connected second upper arm switches (SUHb to SWHb) and second lower arm switches (SULb to SWLb) corresponding to the number of phases; a capacitor (16) connected in parallel to the series connection of the second upper arm switch and the second lower arm switch; a positive bus bar (11) electrically connecting the high-potential side terminals of the first upper arm switch and the second upper arm switch in each phase; a negative bus bar (12) electrically connecting the low-potential side terminals of the first lower arm switch and the second lower arm switch in each phase; and a switching switch (13, 17) provided on a target bus bar which is at least one of the positive bus bar and the negative bus bar. In a program applied to a system including these components, in each phase, the low-potential side terminal of the first upper arm switch and the high-potential side terminal of the first lower arm switch are electrically connected to the first end of the armature winding, and in each phase, the low-potential side terminal of the second upper arm switch and the high-potential side terminal of the second lower arm switch are electrically connected to the second end of the armature winding. The switching switch, when turned on, electrically connects the first inverter and the second inverter via the target bus bar, and when turned off, disconnects the electrical connection between the first inverter and the second inverter via the target bus bar. A processor (71) is caused to execute a selection process for selecting a control mode of the first upper arm switch, the first lower arm switch, the second upper arm switch, and the second lower arm switch, and a control process for controlling the on or off of the first upper arm switch, the first lower arm switch, the second upper arm switch, and the second lower arm switch based on the selected control mode. In the selection process, the operating point (Trq*,Based on Nr), as the control mode, Y drive control or H drive control is selected. The Y drive control is to keep the second upper arm switch of each phase on and fixed and the second lower arm switch of each phase off and fixed in the state where the switching switch is off, or to keep the second lower arm switch of each phase on and fixed and the second upper arm switch of each phase off and fixed in the state where the switching switch is off, and at the same time, perform PWM driving control on the first upper arm switch and the first lower arm switch. The H drive control is to perform PWM driving control on the first upper arm switch, the first lower arm switch, the second upper arm switch and the second lower arm switch. In the control process, prior to switching the control mode from the Y drive control to the H drive control, in the Y drive control, a charging control is performed to alternately turn on the set of the second upper arm switches of each phase and the set of the second lower arm switches of each phase., 4. A rotating electrical machine (40) having a multi-phase armature winding (51U to 51W), a first inverter (20) having a number of series-connected first upper arm switches (SUHa to SWHa) and first lower arm switches (SUL a to SWL a) corresponding to the number of phases, wherein the series connection of the first upper arm switch and the first lower arm switch is connected in parallel to a DC power supply (10), a second inverter (30) having a number of series-connected second upper arm switches (SUHb to SWHb) and second lower arm switches (SULb to SWLb), a capacitor (16) connected in parallel to the series connection of the second upper arm switch and the second lower arm switch, in each phase, a positive bus bar (11) electrically connecting the high potential side terminals of the first upper arm switch and the second upper arm switch, in each phase, a negative bus bar (12) electrically connecting the low potential side terminals of the first lower arm switch and the second lower arm switch, a switching switch (13, 17) provided on at least one of the positive bus bar and the negative bus bar as a target bus bar, in a control method of a rotating electrical machine applied to a system including, in each phase, the low potential side terminal of the first upper arm switch and the high potential side terminal of the first lower arm switch are electrically connected to the first end of the armature winding, in each phase, the low potential side terminal of the second upper arm switch and the high potential side terminal of the second lower arm switch are electrically connected to the second end of the armature winding, the switching switch, when turned on, electrically connects the first inverter and the second inverter via the target bus bar, and when turned off, cuts off the electrical connection between the first inverter and the second inverter via the target bus bar, a selection step of selecting a control mode of the first upper arm switch, the first lower arm switch, the second upper arm switch, and the second lower arm switch, and a control step of controlling the on or off of the first upper arm switch, the first lower arm switch, the second upper arm switch, and the second lower arm switch based on the selected control mode, comprising, in the selection step, the operating point (Trq*,Based on Nr), as the control mode, Y drive control or H drive control is selected. The Y drive control is to fix the second upper arm switch of each phase to on and fix the second lower arm switch of each phase to off in the state where the switching switch is off, or to fix the second lower arm switch of each phase to on and fix the second upper arm switch of each phase to off in the state where the switching switch is off, and at the same time, PWM drive the first upper arm switch and the first lower arm switch. The H drive control is to PWM drive the first upper arm switch, the first lower arm switch, the second upper arm switch and the second lower arm switch. In the control step, prior to switching the control mode from the Y drive control to the H drive control, in the Y drive control, a charging control is performed to alternately turn on the set of the second upper arm switches of each phase and the set of the second lower arm switches of each phase. A control method for a rotating electrical machine.

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