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

Abstract

This control device is applied to a system (100) comprising: a rotary electric machine (40); a first inverter (20) connected to a DC power source (10); a second inverter (30); change-over switches (QH, QL); first and second capacitors (15a, 15b); power source switches (MH, ML); and a series-connected body comprising a precharge switch (MP) and a resistor (13). First upper and lower arm switches (SUHa to SWLa) are connected to first ends of windings (51U to 51W), and second upper and lower arm switches (SUHb to SWLb) are connected to second ends of the windings. The control device includes a precharge unit (90, 190, 290) that turns on the precharge switch before the power source switches are turned on. The precharge unit turns off the change-over switches during at least a portion of a precharge period from when the precharge switch is turned on until the voltage of the first capacitor reaches a determination voltage.

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. 2023-221322, filed on December 27, 2023, the contents of which are incorporated herein by reference.

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

[0003] Conventionally, a system for controlling a rotating electric machine using two inverters has been known. In this system, a first inverter is electrically connected to first ends of a multi-phase winding of the rotating electric machine, and a second inverter is electrically connected to second ends of the winding. The first inverter and the second inverter share a common connection line. A DC power supply and a first capacitor are electrically connected in parallel to the first inverter. A second capacitor is electrically connected in parallel to the second inverter. An example of such a technology is disclosed in Patent Document 1.

[0004] Japanese Patent Application Laid-Open No. 2021-125922

[0005] In order to prevent an inrush current from flowing through the system when current begins to flow between the DC power supply and the rotating electric machine, the first capacitor and the second capacitor may be charged via a resistor provided in a path electrically connecting the DC power supply and the first inverter. In this case, there is a concern that the charging period of the capacitors may be longer than when a capacitor is provided only in the first inverter of the first and second inverters.

[0006] The present disclosure has been made in consideration of the above circumstances, and its purpose is to provide a control device, program, and control method for a rotating electric machine that can shorten the charging period of a capacitor.

[0007] The present disclosure relates to a rotating electric machine having windings for multiple phases; a first inverter having first upper arm switches and first lower arm switches connected in series for the number of phases, and the series connection of the first upper arm switches and the first lower arm switches being 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 number of phases; a positive bus bar for each phase electrically connecting a high potential side terminal of the first upper arm switch to a high potential side terminal of the second upper arm switch; a negative bus bar for each phase electrically connecting a low potential side terminal of the first lower arm switch to a low potential side terminal of the second lower arm switch; a changeover switch provided on at least one of the positive bus bar and the negative bus bar; a first capacitor connected in parallel to the series connection of the first upper arm switch and the first lower arm switch; and a second capacitor connected in parallel to the series connection of the second upper arm switch and the second lower arm switch. A control device for a rotating electric machine applied to a system including: a power switch provided in a path electrically connecting the first inverter and the DC power supply; and a series connection of a pre-charge switch and a resistor connected in parallel to the power switch, 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 winding, and 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 winding, and the control device further includes a pre-charge unit that turns on the pre-charge switch before turning on the power switch, and the pre-charge unit turns off the changeover switch during at least a portion of a pre-charge period from when the pre-charge switch is turned on until the voltage of the first capacitor reaches a determination voltage.

[0008] In a control system, when a power switch is turned on, current begins to flow between a DC power supply and a rotating electric machine. In this case, a pre-charge switch may be turned on before the power switch is turned on. If both the first capacitor and the second capacitor are charged during a pre-charge period from when the pre-charge switch is turned on until the voltage of the first capacitor reaches a determination voltage, there is a concern that the pre-charge period will be prolonged. In this regard, the second capacitor can be charged after the end of the pre-charge period, depending on the operating status of the system.

[0009] Therefore, in the present disclosure, the changeover switch is turned off during at least a portion of the precharge period. In this case, the output current of the DC power supply is restricted from flowing to the second capacitor via the positive bus and the negative bus during the precharge period. This allows the degree of voltage increase in the first capacitor to be increased compared to when both the first capacitor and the second capacitor are charged. As a result, the precharge period can be shortened.

[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 a diagram showing an overall configuration of a control system according to a first embodiment; FIG. 2 is a functional block diagram of processing executed by a control device; FIG. 3 is a diagram showing a control mode of H drive control; FIG. 4 is a diagram showing a control mode of Y drive control; FIG. 5 is a flowchart showing the procedure of processing executed by the control device; FIG. 6 is a functional block diagram of processing executed by the control device; FIG. 7 is a flowchart showing the procedure of processing executed by the control device;

[0011] Several embodiments will be described with reference to the drawings. In several embodiments, functionally and / or structurally corresponding and / or associated parts may be designated by the same reference numerals or reference numerals that differ in the hundredth or more digit. For corresponding and / or associated parts, reference may be made to the descriptions of other embodiments.

[0012] A first embodiment of a control device according to the present disclosure will now be described with reference to the drawings. The control device of the present embodiment is mounted on an electrically powered vehicle such as an electric vehicle or a hybrid vehicle, and is applied to an in-vehicle control system.

[0013] As shown in FIG. 1 , the control system 100 includes a battery 10 (corresponding to 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.

[0014] 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 .

[0015] 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.

[0016] In this embodiment, voltage-controlled semiconductor switching elements, more specifically, IGBTs, are used as the switches SUHa to SWLa and SUHb to SWLb. In this embodiment, the high-potential terminal of each switch is the collector, and the low-potential terminal is the emitter. Freewheeling diodes DUHa, DVHa, DWHa, DULa, DVLa, DWLa, DUHb, DVHb, DWHb, DULb, DVLb, and DWLb are connected in anti-parallel to the switches SUHa, SVHa, SWHa, SULa, SVLa, SWLa, SUHb, SVHb, SWHb, SULb, SVLb, and SWLb, respectively.

[0017] The collectors of the first upper arm switches SUHa, SVHa, SWHa of each phase and the collectors of the second upper arm switches SUHb, SVHb, SWHb of each phase are electrically connected by a positive bus 11 such as a bus bar. The emitters of the first lower arm switches SULa, SVLa, SWLa of each phase and the emitters of the second lower arm switches SULb, SVLb, SWLb of each phase are electrically connected by a negative bus 12 such as a bus bar.

[0018] The positive terminal of the battery 10 is electrically connected to the positive bus 11, and the negative terminal of the battery 10 is electrically connected to the negative bus 12. The battery 10 is electrically connected to the buses 11, 12 on the opposite side of the first inverter 20 from the second inverter 30.

[0019] The rotating electric machine 40 is an in-vehicle main motor. A rotor 41 of the rotating electric machine 40 is capable of transmitting power to drive wheels 43 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 rotating electric machine 40 includes a stator 50. The stator 50 includes armature windings, namely, a U-phase winding 51U, a V-phase winding 51V, and a W-phase winding 51W. The phase windings 51U, 51V, and 51W are arranged with an electrical angle of 120°. The phase windings 51U, 51V, and 51W are open-connected, and both ends of each phase winding 51U, 51V, and 51W are electrically connected to the first inverter 20 or the second inverter 30.

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

[0022] The control system 100 includes a positive-side selector switch QH and a negative-side selector switch QL. The positive-side selector switch QH is provided on the positive-side bus 11 between the first inverter 20 and the second inverter 30. The negative-side selector switch QL is provided on the negative-side bus 12 between the first inverter 20 and the second inverter 30. When turned on, each of the selector switches QH and QL electrically connects the first inverter 20 and the second inverter 30, and when turned off, electrically disconnects the first inverter 20 and the second inverter 30. In this embodiment, the selector switches QH and QL are controlled by a control device 60 included in the control system 100. As will be described later, each of the selector switches QH and QL is provided to switch the driving state of the control system 100.

[0023] For example, each of the changeover switches QH, QL is a semiconductor switching element such as an IGBT or a relay. When an IGBT is used as each of the changeover switches QH, QL, a freewheel diode is connected in parallel to each of the changeover switches QH, QL. In this case, the anode of the freewheel diode connected in parallel to the positive-side changeover switch QH is electrically connected to the second inverter 30 side, and the cathode is electrically connected to the first inverter 20 side. Furthermore, the anode of the freewheel diode connected in parallel to the negative-side changeover switch QL is electrically connected to the first inverter 20 side, and the cathode is electrically connected to the second inverter 30 side.

[0024] The control system 100 includes a first capacitor 15a and a second capacitor 15b. A first end of the first capacitor 15a is electrically connected to the positive bus 11 between the battery 10 and the first inverter 20. A second end of the first capacitor 15a is electrically connected to the negative bus 12 between the negative terminal of the battery 10 and the first inverter 20. In other words, the first capacitor 15a is connected in parallel to the series connection of the first upper arm switches SUHa, SVHa, SWHa of each phase and the first lower arm switches SULa, SVLa, SWLa of each phase.

[0025] A first end of the second capacitor 15b is electrically connected to the positive bus 11 on the side opposite the positive selector switch QH with respect to the second inverter 30. A second end of the second capacitor 15b is electrically connected to the negative bus 12 on the side opposite the negative selector switch QL with respect to the second inverter 30. In other words, the second capacitor 15b is connected in parallel to the series-connected body of the second upper arm switches SUHb, SVHb, SWHb of each phase and the second lower arm switches SULb, SVLb, SWLb of each phase.

[0026] The control system 100 includes a positive power switch MH and a negative power switch ML. The positive power switch MH is provided between the battery 10 and a connection point of the positive bus 11 with a first end of the first capacitor 15a. The negative power switch ML is provided between the battery 10 and a connection point of the negative bus 12 with a second end of the first capacitor 15a. For example, each of the power switches MH and ML is a relay or a semiconductor switching element. Each of the power switches MH and ML is controlled by a control device 60.

[0027] The control system 100 includes a precharge switch MP and a resistor 13. A series connection of the precharge switch MP and the resistor 13 is connected in parallel to the negative-side power switch ML. The precharge switch MP is a relay or a semiconductor switching element. The precharge switch MP is controlled by a control device 60.

[0028] The control system 100 includes a first voltage sensor 61, a second voltage sensor 62, a current sensor 63, a rotation angle sensor 64, a start switch 65, and a parking brake sensor 66. The first voltage sensor 61 detects the voltage of the first capacitor 15a. The second voltage sensor 62 detects the voltage of the second capacitor 15b. The current sensor 63 detects the phase current flowing through each of the phase windings 51U, 51V, and 51W. In this embodiment, the current sensor 63 is provided on the first inverter 20 side of each of the phase windings 51U, 51V, and 51W. Note that the current sensor 63 may also be provided on the second inverter 30 side of each of the phase windings 51U, 51V, and 51W. The rotation angle sensor 64 is, for example, a resolver and detects the electrical angle of the rotor 41. The detected values ​​of the sensors 61 to 64 are input to the control device 60.

[0029] The start switch 65 is, for example, an ignition switch or a push-button start switch, and is operated by the vehicle user. The parking brake sensor 66 detects whether a parking brake that applies braking force to the vehicle wheels is activated. A signal notifying that the start switch 65 has been turned on or off and a signal notifying whether the parking brake is activated are input to the control device 60.

[0030] The control device 60 is an electronic control unit (ECU) that performs various controls of the control system 100, and includes a processor 60a and a storage unit 60b 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 one control device 60 in FIG. 1 .

[0031] The memory unit 60b 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 60. The memory provides the processor 60a with a working area for temporary use when the processor 60a 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 60a, 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 processing, such as those shown in Figures 5, 7, 12, and 15, which will be described later.

[0032] For example, program information stored in a non-transient physical recording medium is installed in the storage unit 60b. 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 60b.

[0033] In order to control the control variable of the rotary electric machine 40 to a command value, the control device 60 controls the on / off of the changeover switches QH, QL, the switches SUHa to SWLa of the first inverter 20, and the switches SUHb to SWLb of the second inverter 30 while keeping the power switches MH, ML 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 60. As shown in FIG.

[0035] The dq-axis 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 torque command value Trq* received from a higher-level control device than the control device 60.

[0036] The first 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 63 and the electrical angle θr detected by the rotation angle sensor 64.

[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 second 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 determines whether the control system 100 should perform Y drive control or H drive control. In the present embodiment, the selection unit 85 selects whether the control system 100 should perform Y drive control or H drive control based on the operating point of the rotating electric machine 40, which is determined by the calculated rotation speed Nr and torque command value Trq*, and on 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 torque command value Trq*. The control map information is stored in the storage unit 60b.

[0041] The switch control unit 86 generates a carrier signal for generating drive signals for the switches SUHa to SWLa and SUHb to SWLb in the first and second inverters 20 and 30. For example, the carrier signal is a triangular wave signal. The drive signals are comprised of switch on and off commands.

[0042] 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 first detected voltage V1r which is the voltage detected by the first voltage sensor 61, and the generated carrier signal.

[0043] 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 first detected voltage V1r. 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 first detected voltage V1r.

[0044] 3, the switch control unit 86 performs H drive control by turning on the changeover switches QH, QL 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, 30 based on a magnitude comparison between the U-, V-, and W-phase normalized command values ​​Dutyu, Dutyv, and Dutyw and the carrier signal.

[0045] On the other hand, when Y drive control is selected by the selector 85, the switch control unit 86 performs Y drive control by turning off the changeover switches QH and QL and PWM-driving the switches SUHa to SWLa of the first inverter 20, as shown in FIG. 4 . The switch control unit 86 also fixes the upper arm switches SUHb, SVHb, and SWHb of the second inverter 30 to on and fixes the lower arm switches SULb, SVLb, and SWLb of the second inverter 30 to off. This results in a star connection of the phase windings 51U, 51V, and 51W 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 magnitude comparison between the U-, V-, and W-phase normalized command values ​​Dutyu, Dutyv, and Dutyw and the carrier signal.

[0046] 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 in the first and second inverters 20 and 30. As a result, the on / off of the switches SUHa-SWLa and SUHb-SWLb in the first and second inverters 20 and 30 is controlled in accordance with the drive signal.

[0047] The switching patterns of the switches SUHa to SWLa and SUHb to SWLb, which are switched according to the drive signal in the H drive control, are shifted in phase by 120° in electrical angle in each phase. Also, the switching patterns of the switches SUHa to SWLa in the first inverter 20, which are switched according to the drive signal in the Y drive control, are shifted in phase by 120° in electrical angle in each phase.

[0048] 5 is a flowchart showing the control process of the rotary electric machine 40 executed by the control device 60. The process shown in FIG. 5 is repeatedly executed by the processor 60a of the control device 60, for example, at a predetermined control cycle.

[0049] In step S10, the selection unit 85 acquires the torque command value Trq* and the rotation speed Nr calculated by the speed calculation unit 84.

[0050] In step S11, the selection unit 85 selects either the Y drive control or the H drive control based on the torque command value Trq* and the rotation speed Nr.

[0051] If the Y drive state is selected in step S11, the process proceeds to step S13, where the switch control unit 86 executes the Y drive control shown in Fig. 4. On the other hand, if the H drive state is selected in step S11, the process proceeds to step S14, where the switch control unit 86 executes the H drive control shown in Fig. 3.

[0052] Incidentally, when starting to pass current between the battery 10 and the rotating electric machine 40, the control device 60 may turn on the positive power switch MH and the pre-charge switch MP and turn off the negative power switch ML to pre-charge the first capacitor 15a. In this case, the current passing between the battery 10 and the rotating electric machine 40 is limited by the resistor 13. Therefore, the flow of inrush current between the battery 10 and the rotating electric machine 40 is suppressed.

[0053] In a configuration in which both capacitors 15a and 15b are provided in the control system 100, there is a concern that the precharge period Tp will be longer than in a configuration in which only the first capacitor 15a of both capacitors 15a and 15b is provided in the control system 100. The precharge period Tp is the period from when the precharge switch MP is turned on until the voltage of the first capacitor 15a reaches the determination voltage Vth. The determination voltage Vth is a value used to determine whether or not to end the precharge.

[0054] In a comparative example, the switches QH and QL are turned on during the precharge period Tp, and both the capacitors 15a and 15b are charged. In this case, during the precharge period Tp, the voltage Vo of each of the capacitors 15a and 15b changes according to the following equation (eq1):

[0055] Here, VB is the terminal voltage of the battery 10, C is the combined capacitance of the capacitors 15a and 15b, and R is the resistance value of the resistor 13. Because the combined capacitance C of the capacitors 15a and 15b is large, the increase in the voltage Vo of each of the capacitors 15a and 15b may be suppressed. In this case, there is a concern that the precharge period Tp may become longer.

[0056] Therefore, in this embodiment, the control device 60 has the following configuration to shorten the precharge period Tp.

[0057] As shown in FIG. 6 , the control device 60 includes a precharge unit 90 and a charge control unit 91. A signal indicating that the start switch 65 has been turned on or off and a first detection voltage V1r are input to the precharge unit 90. When the signal indicating that the start switch 65 has been turned on is input, the precharge unit 90 turns on the positive power switch MH and the precharge switch MP and turns off the negative power switch ML and the selector switches QH and QL. In this case, current is supplied from the battery 10 to the first capacitor 15a via the resistor 13. Furthermore, current flow between the battery 10 and the second capacitor 15b is interrupted.

[0058] The precharge unit 90 determines whether the first detection voltage V1r has reached a determination voltage Vth of the first capacitor 15a. The determination voltage Vth is a value determined based on the terminal voltage VB (e.g., rated voltage) of the battery 10, and is, for example, 80% to 95%, 85% to 95%, or 90% to 95% of the terminal voltage VB of the battery 10. When the precharge unit 90 determines that the first detection voltage V1r has reached the determination voltage Vth, it turns on the positive-side power switch MH and the negative-side power switch ML and turns off the precharge switch MP.

[0059] The precharge unit 90 outputs an end notification signal Sga to notify whether or not precharge has been completed to the charge control unit 91. The end notification signal Sga is a binary signal, and a logic L indicates that precharge is in progress, and a logic H indicates that precharge has been completed.

[0060] The charging control unit 91 receives the end notification signal Sga and the second detected voltage V2r, which is the voltage detected by the second voltage sensor 62. When the end notification signal Sga of logic H is received, the charging control unit 91 performs charging control to supply the output current of the battery 10 to the second capacitor 15b.

[0061] In this embodiment, the charge control unit 91 controls the charge by fixing the negative-side selector switch QL to ON and chopper-controlling the positive-side selector switch QH. In this case, during a period in one switching cycle in which the positive-side selector switch QH is ON, current is supplied from the battery 10 to the second capacitor 15b via the buses 11 and 12. During a period in one switching cycle in which the positive-side selector switch QH is OFF, current supply from the battery 10 to the second capacitor 15b is interrupted. The charge control unit 91 adjusts the duty ratio "Ton / Tsw," which is the ON period Ton of the positive-side selector switch QH in one switching cycle Tsw, thereby adjusting the magnitude of the current supplied from the battery 10 to the second capacitor 15b. During charge control, the switch control unit 86 turns off the switches SUHa to SWLa and SUHb to SWLb.

[0062] Fig. 7 shows a flowchart of the process executed by the control device 60. The process shown in Fig. 7 is executed by the processor 60a of the control device 60 when, for example, a signal notifying that the start switch 65 has been turned on is input.

[0063] In step S20, the precharge unit 90 turns off the changeover switches QH and QL. In step S21, the precharge unit 90 turns on the positive power switch MH and the precharge switch MP, and turns off the negative power switch ML. This starts the precharge period Tp. In this case, the precharge unit 90 outputs a logic L end notification signal Sga to the charge control unit 91.

[0064] In step S22, the precharge unit 90 determines whether the first detection voltage V1r has reached the determination voltage Vth. The precharge unit 90 continues charging the first capacitor 15a until it determines that the first detection voltage V1r has reached the determination voltage Vth. If the determination in step S22 is affirmative, the process proceeds to step S23.

[0065] In step S23, the precharge unit 90 turns on the positive power switch MH and the negative power switch ML, and turns off the precharge switch MP. This ends the precharge period Tp. In this case, the precharge unit 90 outputs a logic H end notification signal Sga to the charge control unit 91.

[0066] In step S24, charging control is performed by the charging control unit 91. In this embodiment, as the charging control, the charging control unit 91 fixes the negative electrode side changeover switch QL to ON and performs chopper control on the positive electrode side changeover switch QH, as described above with reference to FIG.

[0067] In step S25, the charge control unit 91 determines whether the second detected voltage V2r has reached the terminal voltage VB of the battery 10. The charge control unit 91 continues charge control until it determines that the second detected voltage V2r has reached the terminal voltage VB of the battery 10. If the determination in step S25 is affirmative, the process proceeds to step S26.

[0068] In step S26, the switch control unit 86 starts driving the rotating electric machine 40. Specifically, the switch control unit 86 performs Y drive control or H drive control selected in the control process for the rotating electric machine 40 described above with reference to FIG.

[0069] Next, with reference to FIG. 8 , the effects of the above-described process will be described. In FIG. 8 , (a) shows the transitions of the first detection voltage V1r and the second detection voltage V2r, (b) shows the on / off state of the positive power switch MH, (c) shows the on / off state of the negative power switch ML, (d) shows the on / off state of the precharge switch MP, (e) shows the on / off state of the positive selector switch QH, (f) shows the on / off state of the negative selector switch QL, and (g) shows the logic of the end notification signal Sga. Note that in FIG. 8(a), the first detection voltage V1r in this embodiment is shown by a solid line, and the second detection voltage V2r is shown by a dashed line. Also, in FIG. 8(a), the voltage Vo in a comparative example in which both capacitors 15a and 15b are charged during the precharge period Tp is shown by a dashed line.

[0070] At time t1, the user turns on the start switch 65. During the period from time t1 to time t2, the precharge unit 90 turns on the positive power switch MH and the precharge switch MP and turns off the negative power switch ML and the changeover switches QH and QL. The period from time t1 to time t2 is the precharge period Tp.

[0071] In this embodiment, during the precharge period Tp, the changeover switches QH and QL are turned off. In this case, the current flow between the battery 10 and the second capacitor 15b via the buses 11 and 12 is interrupted, and only the first capacitor 15a of the capacitors 15a and 15b is charged. This allows the capacitance of the capacitors charged during the precharge period Tp to be smaller than in the comparative example. Therefore, the rate of increase of the first detection voltage V1r, indicated by the solid line, can be made higher than the rate of increase of the voltage Vo in the comparative example, indicated by the dashed-dotted line. As a result, the precharge period Tp can be shortened.

[0072] At time t2, the precharge unit 90 determines that the first detection voltage V1r has reached the determination voltage Vth. In this case, the precharge unit 90 turns on the negative power switch ML and turns off the precharge switch MP. The precharge unit 90 then outputs a logic H end notification signal Sga.

[0073] After time t2, the charge control unit 91 performs charge control. As a result, the second capacitor 15b is charged and the second detection voltage V2r increases. Note that Fig. 8 shows an example of charge control in which the negative electrode side changeover switch QL is fixed to ON and the positive electrode side changeover switch QH is chopper controlled.

[0074] At time t3, the charge control unit 91 determines that the second detection voltage V2r has reached the terminal voltage VB of the battery 10. In this case, the charge control unit 91 stops charge control. After time t3, the switch control unit 86 starts driving the rotating electric machine 40. Note that FIG. 8 shows an example in which the H drive state is selected and the selector switches QH and QL are turned on.

[0075] In this embodiment, after the end of the precharge period Tp, the precharge switch MP is turned off and the power switches MH and ML are turned on, and charging control of the second capacitor 15b is performed. This makes it possible to prevent the control process of the rotating electric machine 40 from becoming unstable due to a low voltage of the second capacitor 15b. Furthermore, since current is supplied from the battery 10 to the second capacitor 15b without passing through the resistor 13, the second capacitor 15b can be quickly charged.

[0076] The charge control unit 91 controls the charge by fixing the negative electrode side changeover switch QL to ON and chopper-controlling the positive electrode side changeover switch QH, thereby adjusting the charge current of the second capacitor 15b with simple control.

[0077] <Modification of First Embodiment> - Instead of fixing the negative selector switch QL to ON and chopper-controlling the positive selector switch QH as charge control, the charge control unit 91 may fix the positive selector switch QH to ON and chopper-control the negative selector switch QL. Furthermore, the charge control unit 91 may chopper-control the selector switches QH and QL as charge control.

[0078] The charging control shown in Fig. 9 may be performed. In this embodiment, as the charging control, zero-axis current control is performed in which a zero-axis current flows through each of the phase windings 51U, 51V, and 51W in the control process of the rotating electric machine 40 described above with reference to Fig. 2. The zero-axis current is the total current of the phase currents flowing through each of the phase windings 51U, 51V, and 51W.

[0079] Specifically, when the end notification signal Sga of logic H is input, the zero-axis command value calculation unit 191 turns off the changeover switches QH and QL and calculates the zero-axis current command value I0*. The zero-axis current command value I0* is a command value of the zero-axis current to be flowed through the phase windings 51U, 51V, and 51W from the first terminals 51Ua, 51Va, and 51Wa toward the second terminals 51Ub, 51Vb, and 51Wb. The zero-axis command value calculation unit 191 outputs the calculated zero-axis current command value I0* to the current feedback unit 182. Note that, instead of turning off the changeover switches QH and QL during the execution of charging control, the zero-axis command value calculation unit 191 may turn off either one of the changeover switches QH and QL.

[0080] The first conversion unit 181 calculates the d-axis current value Idr, the q-axis current value Iqr, and the zero-axis current value I0r based on the phase currents Iur, Ivr, and Iwr detected by the current sensor 63 and the electrical angle θr detected by the rotation angle sensor 64. The first conversion unit 181 calculates the sum of the phase currents Iur, Ivr, and Iwr as the zero-axis current value I0r. The first conversion unit 181 outputs the calculated d-axis current value Idr, q-axis current value Iqr, and zero-axis current value I0r to the current feedback unit 182. The first conversion unit 181 corresponds to a "current value calculation unit."

[0081] The current feedback unit 182 calculates a d-axis voltage command value Vd*, a q-axis voltage command value Vq*, and a zero-axis voltage command value V0* based on the d- and q-axis current command values ​​Id*, Iq*, and the zero-axis current command value I0*, as well as the d- and q-axis current values ​​Idr, Iqr, and the zero-axis current value I0r. Specifically, the current feedback unit 182 calculates a zero-axis current deviation, which is the difference between the zero-axis current command value I0* and the zero-axis current value I0r, and calculates a zero-axis voltage command value V0* as a manipulated variable for feedback control to adjust the calculated zero-axis current deviation to zero. The current feedback unit 182 outputs the calculated d-axis voltage command value Vd*, q-axis voltage command value Vq*, and zero-axis voltage command value V0* to the second conversion unit 183. The feedback control is, for example, proportional-plus-integral control.

[0082] The second conversion unit 183 calculates U-, V-, and W-phase voltage command values ​​Vu*, Vv*, and Vw* based on the d- and q-axis voltage command values ​​Vd* and Vq*, the zero-axis voltage command value V0*, and the electrical angle θr. The switch control unit 86 generates drive signals for the switches SUHa-SWLa and SUHb-SWLb of the inverters 20 and 30, as in the case described above with reference to FIG. 2 . In this embodiment, the d- and q-axis command value calculation unit 80, the switch control unit 86, the first conversion unit 181, and the zero-axis command value calculation unit 191 correspond to a "charge control unit."

[0083] According to this embodiment, in the control process for the rotating electric machine 40, switching control of the switches SUHa-SWLa and SUHb-SWLb is performed so that a zero-axis current flows from the first terminals 51Ua, 51Va, and 51Wa of the respective phase windings 51U, 51V, and 51W toward the second terminals 51Ub, 51Vb, and 51Wb of the respective phase windings 51U, 51V, and 51W. In this case, while driving the rotating electric machine 40, a current can flow from the battery 10 to the second inverter 30 via the respective phase windings 51U, 51V, and 51W. Therefore, while driving the rotating electric machine 40, the second capacitor 15b can be charged by the current flowing into the second inverter 30.

[0084] As shown in FIG. 10, the charge control unit 291 may perform step-down control as charge control, in which the inverters 20 and 30 and the phase windings 51U, 51V, and 51W operate as step-down circuits.

[0085] Specifically, a signal detected by the parking brake sensor 66 is input to the charge control unit 291. When the end notification signal Sga of logic H is input and a signal indicating that the parking brake is applied is input, the charge control unit 291 performs voltage step-down control. When performing voltage step-down control, the charge control unit 291 turns off the positive electrode side selector switch QH and turns on the negative electrode side selector switch QL.

[0086] The charging control unit 291 receives the first detection voltage V1r and the second detection voltage V2r. The charging control unit 291 calculates the duty ratio of the first upper arm switches SUHa, SVHa, and SWHa of each phase based on the received first detection voltage V1r and second detection voltage V2r. The duty ratio is the ratio of the on-period of the first upper arm switches SUHa, SVHa, and SWHa of each phase to one switching cycle. The charging control unit 291 generates drive signals for turning on and off the first upper arm switches SUHa, SVHa, and SWHa of each phase based on the calculated duty ratio. The charging control unit 291 generates off commands for the first lower arm switches SULa, SVLa, and SWLa of each phase and the second lower arm switches SULb, SVLb, and SWLb of each phase, and on commands for the second upper arm switches SUHb, SVHb, and SWHb of each phase.

[0087] The switches SUHa to SWLa and SUHb to SWLb are driven based on drive signals generated by the charge control unit 291. In this case, in each phase, during the on period of the first upper arm switches SUHa, SVHa, SWHa, current flows through a closed circuit including the battery 10, the first upper arm switches SUHa, SVHa, SWHa, the windings 51U, 51V, 51W, the second upper arm switches SUHb, SVHb, SWHb, the second capacitor 15b, and the negative pole side bus 12. As a result, the second capacitor 15b is charged, and magnetic energy is stored in the windings 51U, 51V, 51W, in each phase.

[0088] Meanwhile, in each phase, while the first upper-arm switches SUHa, SVHa, SWHa are off, the magnetic energy stored in the windings 51U, 51V, 51W is released. In this case, in each phase, a current flows through a closed circuit including the windings 51U, 51V, 51W, the second upper-arm switches SUHb, SVHb, SWHb, the second capacitor 15b, the negative bus 12, and the first lower-arm diodes DULa, DVLa, DWLa. This charges the second capacitor 15b.

[0089] By performing the above-described step-down control, the output voltage of the battery 10 is stepped down, and the stepped-down voltage is applied to the second capacitor 15b. This allows the second capacitor 15b to be charged. Furthermore, since step-down control can be performed for each phase, a large charging current can be passed through the second capacitor 15b. This makes it possible to realize a configuration suitable for shortening the charging time of the second capacitor 15b.

[0090] When the step-down control is performed, a current flows through each of the phase windings 51U, 51V, and 51W. In this case, torque may be generated in the rotary electric machine 40. In this regard, in this embodiment, the step-down control is performed when a signal indicating that the parking brake is activated is input. This makes it possible to prevent the drive wheels 43 from rotating while the step-down control is being performed.

[0091] Second Embodiment The second embodiment will be described below with reference to the drawings, focusing on the differences from the first embodiment. This embodiment differs from the first embodiment in that the changeover switches QH and QL are turned on during a portion of the precharge period Tp. Note that, hereinafter, the determination voltage Vth described in the first embodiment will be referred to as a "first determination voltage Vth1."

[0092] 11 , a signal notifying that the start switch 65 has been turned on or off is input to the precharge unit 190. When the signal indicating that the start switch 65 has been turned on is input to the precharge unit 190, the precharge unit 190 turns on the positive power switch MH, the precharge switch MP, and the changeover switches QH and QL, and turns off the negative power switch ML. In this case, current is supplied from the battery 10 to the capacitors 15 a and 15 b via the resistor 13.

[0093] The precharge unit 190 receives the first detection voltage V1r and the second detection voltage V2r. The precharge unit 190 determines whether the second detection voltage V2r has reached a second determination voltage Vth2. The second determination voltage Vth2 is lower than the first determination voltage Vth1. In this embodiment, the second determination voltage Vth2 is half the terminal voltage VB of the battery 10.

[0094] When the precharge unit 190 determines that the second detection voltage V2r has reached the second determination voltage Vth2, it turns off the changeover switches QH and QL, thereby interrupting the flow of electricity between the battery 10 and the second capacitor 15b.

[0095] As in the first embodiment, when the precharge unit 190 determines that the first detection voltage V1r has reached the first determination voltage Vth1, it turns on the power switches MH and ML and turns off the precharge switch MP. This ends the precharge period Tp. That is, in this embodiment, the precharge unit 190 turns on the changeover switches QH and QL during a specific period of the precharge period Tp until the second detection voltage V2r reaches the second determination voltage Vth2. The precharge unit 190 turns off the changeover switches QH and QL during periods other than the specific period of the precharge period Tp.

[0096] Fig. 12 shows a flowchart of the process executed by the control device 60. The process shown in Fig. 12 is executed by the processor 60a of the control device 60 when, for example, a signal notifying that the start switch 65 has been turned on is input.

[0097] In step S30, the switches QH and QL are turned on in the precharge unit 190. In step S31, the positive power switch MH and the precharge switch MP are turned on and the negative power switch ML is turned off in the precharge unit 190. This starts the precharge period Tp.

[0098] In step S32, the precharge unit 190 determines whether the second detection voltage V2r has reached the second determination voltage Vth2. The precharge unit 190 continues charging the capacitors 15a and 15b until it determines that the second detection voltage V2r has reached the second determination voltage Vth2. If the determination in step S32 is affirmative, the process proceeds to step S33. In step S33, the precharge unit 190 turns off the selector switches QH and QL. This stops charging the second capacitor 15b. Charging of the first capacitor 15a continues.

[0099] In step S34, the precharge unit 190 determines whether the first detection voltage V1r has reached the first determination voltage Vth1. The precharge unit 190 continues charging the first capacitor 15a until it determines that the first detection voltage V1r has reached the first determination voltage Vth1. If the determination in step S34 is affirmative, the process proceeds to step S35.

[0100] In step S35, the precharge unit 190 turns on the positive power switch MH and the negative power switch ML, and turns off the precharge switch MP, thereby ending the precharge period Tp. In step S36, the switch control unit 86 starts driving the rotating electrical machine 40.

[0101] Next, the effects of the above-described process will be described with reference to Fig. 13. Fig. 13(a) to (f) correspond to Fig. 8(a) to (f) above.

[0102] At time t1, the user turns on the start switch 65. At time t2, the precharge unit 190 determines that the second detection voltage V2r has reached the second determination voltage Vth2. At time t3, the precharge unit 190 determines that the first detection voltage V1r has reached the first determination voltage Vth1. The period from time t1 to time t3 is the precharge period Tp. Within the precharge period Tp, the period from time t1 to time t2 is the specific period.

[0103] In this embodiment, during the period from time t2 to time t3 during the precharge period Tp, the changeover switches QH and QL are turned off, and charging of the second capacitor 15b is stopped. This limits the output current of the battery 10 from flowing to the second capacitor 15b via the buses 11 and 12 during a portion of the precharge period Tp. Therefore, charging of the first capacitor 15a can be performed more quickly than when the capacitors 15a and 15b are charged throughout the precharge period Tp. As a result, the precharge period Tp can be shortened.

[0104] During a specific period from time t1 to time t2 during the precharge period Tp, the changeover switches QH and QL are turned on. As a result, the second capacitor 15b is charged to half the terminal voltage VB of the battery 10 during the precharge period Tp. Therefore, when Y drive control is performed after the end of the precharge period Tp, control for charging the second capacitor 15b is not required. Furthermore, when H drive control is performed after the end of the precharge period Tp, the period for raising the voltage of the second capacitor 15b to the terminal voltage VB of the battery 10 can be shortened.

[0105] <Modification of the Second Embodiment> The second determination voltage Vth2 is not limited to half the terminal voltage VB of the battery 10. Specifically, when Y drive control is performed after the end of the precharge period Tp, the second determination voltage Vth2 may be any value less than VB / 2. For example, the second determination voltage Vth2 may be 10% to 99%, 20% to 99%, 30% to 99%, 40% to 99%, 50% to 99%, 60% to 99%, 70% to 99%, 88% to 99%, or 90% to 99% of VB / 2.

[0106] Furthermore, when H-drive control is performed after the end of the precharge period Tp, the second determination voltage Vth2 may be a value less than the first determination voltage Vth1. For example, the second determination voltage Vth2 may be 10% to 99%, 20% to 99%, 30% to 99%, 40% to 99%, 50% to 99%, 60% to 99%, 70% to 99%, 88% to 99%, or 90% to 99% of the first determination voltage Vth1.

[0107] In step S33 of FIG. 12, in the precharge unit 190, either one of the switches QH and QL may be turned off.

[0108] Third Embodiment A third embodiment will be described below with reference to the drawings, focusing on differences from the first embodiment. This embodiment differs from the first embodiment in that charging control is performed to supply the output current of the battery 10 to the second capacitor 15b during a part of the precharge period Tp.

[0109] More specifically, as shown in FIG. 14 , when a signal indicating that the start switch 65 is turned on is input, the precharge unit 290 turns on the positive power switch MH and the precharge switch MP and turns off the negative power switch ML and the changeover switches QH and QL. The precharge unit 290 then executes processing for charge control. In this embodiment, as charge control, the precharge unit 290 fixes the negative changeover switch QL to on and chopper-controls the positive changeover switch QH, as described above in FIG. 6 . In this case, the precharge unit 290 implements the function of the charge control unit 91 described above in FIG. 6 .

[0110] The first detection voltage V1r and the second detection voltage V2r are input to the precharge unit 290. The precharge unit 290 determines whether the second detection voltage V2r has reached the second determination voltage Vth2. If the precharge unit 290 determines that the second detection voltage V2r has reached the second determination voltage Vth2, it stops charging control. Then, the precharge unit 290 turns off the switches QH and QL.

[0111] As in the first embodiment, when the precharge unit 290 determines that the first detection voltage V1r has reached the first determination voltage Vth1, it turns on the power switches MH and ML and turns off the precharge switch MP. This ends the precharge period Tp. In other words, in this embodiment, the precharge unit 290 performs charging control during a specific period of the precharge period Tp, until the second detection voltage V2r reaches the second determination voltage Vth2. The precharge unit 290 turns off the changeover switches QH and QL during periods other than the specific period of the precharge period Tp.

[0112] Fig. 15 shows a flowchart of the process executed by the control device 60. The process shown in Fig. 15 is executed by the processor 60a of the control device 60 when, for example, a signal notifying that the start switch 65 has been turned on is input.

[0113] In step S40, the positive power switch MH and the precharge switch MP are turned on and the negative power switch ML is turned off in the precharge section 290. This starts the precharge period Tp.

[0114] In step S41, charging control is performed in the precharge unit 290. In this embodiment, as charging control in the precharge unit 290, the negative electrode side changeover switch QL is fixed to ON and the positive electrode side changeover switch QH is chopper controlled.

[0115] In step S42, the precharge unit 290 determines whether the second detection voltage V2r has reached the second determination voltage Vth2. In this case, the precharge unit 290 continues charging control until it determines that the second detection voltage V2r has reached the second determination voltage Vth2. If the determination in step S42 is affirmative, the process proceeds to step S43.

[0116] In step S43, charging control is stopped in the precharge unit 290. In step S44, the changeover switches QH and QL are turned off, so that charging of the first capacitor 15a continues and charging of the second capacitor 15b is stopped.

[0117] In step S45, the precharge unit 290 determines whether the first detection voltage V1r has reached the first determination voltage Vth1. The precharge unit 290 continues charging the first capacitor 15a until it determines that the first detection voltage V1r has reached the first determination voltage Vth1. If the determination in step S45 is affirmative, the process proceeds to step S46.

[0118] In step S46, the precharge unit 290 turns on the positive power switch MH and the negative power switch ML, and turns off the precharge switch MP, thereby ending the precharge period Tp. In step S47, the switch control unit 86 starts driving the rotating electric machine 40.

[0119] Next, with reference to FIG. 16, the effects of executing the above-described process will be described. FIGS. 16(a) to 16(f) correspond to the above-described FIGS. 13(a) to 13(f). The explanations for times t1, t2, and t3 in FIG. 16 are the same as those for times t1, t2, and t3 in FIG. 13, and therefore will not be repeated. FIG. 16 shows an example in which, as charge control, the negative electrode side changeover switch QL is fixed to ON and the positive electrode side changeover switch QH is chopper controlled during a specific period from time t1 to time t2 within the precharge period Tp.

[0120] In this embodiment, as in the second embodiment, the changeover switches QH and QL are turned off during the period from time t2 to time t3 during the precharge period Tp. This restricts the output current of the battery 10 from flowing to the second capacitor 15b via the buses 11 and 12 during the precharge period Tp. Therefore, the first capacitor 15a can be precharged more quickly than when the capacitors 15a and 15b are charged throughout the precharge period Tp. As a result, the precharge period Tp can be shortened.

[0121] Charging control is performed during the period from time t1 to time t2 during the precharge period Tp. As a result, the voltage of the second capacitor 15b is increased during the precharge period Tp. In this embodiment, the voltage of the second capacitor 15b is increased to half the terminal voltage VB of the battery 10. Therefore, when Y drive control is performed after the end of the precharge period Tp, control to charge the second capacitor 15b is not required. Furthermore, when H drive control is performed after the end of the precharge period Tp, the period during which the voltage of the second capacitor 15b is increased to the terminal voltage VB of the battery 10 can be shortened.

[0122] Other Embodiments The above-described embodiments may be modified as follows.

[0123] In the third embodiment, the precharge unit 290 may execute a process of fixing the positive selector switch QH to ON and chopper-controlling the negative selector switch QL as the process for controlling charging, instead of fixing the negative selector switch QL to ON and chopper-controlling the positive selector switch QH. Also, the precharge unit 290 may execute a process of chopper-controlling the selector switches QH and QL as the process for controlling charging.

[0124] In the third embodiment, the precharge unit 290 may execute a process for performing zero-axis current control in the control process for the rotary electric machine 40, as described above in Fig. 9 , as a process for performing charge control. In this case, the precharge unit 290 realizes the functions of the dq-axis command value calculation unit 80, the switch control unit 86, the first conversion unit 181, the current feedback unit 182, the second conversion unit 183, and the zero-axis command value calculation unit 191 shown above in Fig. 9 .

[0125] In the third embodiment, the precharge unit 290 may perform the step-down control as the charge control, as described above in Fig. 10. In this case, the precharge unit 290 realizes the function of the charge control unit 291 shown above in Fig. 10.

[0126] In the third embodiment, the second determination voltage Vth2 may be the same value as that described in the second embodiment and the modified example of the second embodiment.

[0127] In the first embodiment, the control system 100 may include either one of the changeover switches QH and QL.

[0128] When the control system 100 is provided with only the positive-side changeover switch QH of the changeover switches QH, QL, the process in Fig. 7 can be modified and executed as follows: In step S20, the precharge unit 90 turns off the positive-side changeover switch QH. In step S24, as charge control, it is possible to perform chopper control of the positive-side changeover switch QH, or to perform step-down control or zero-axis current control with the positive-side changeover switch QH turned off.

[0129] When the control system 100 is provided with only the negative-side changeover switch QL of the changeover switches QH, QL, the process in Fig. 7 can be modified and executed as follows: In step S20, the precharge unit 90 turns off the negative-side changeover switch QL. In step S24, the charge control unit 91 can perform charge control such as chopper control of the negative-side changeover switch QL or zero-axis current control with the negative-side changeover switch QL turned off.

[0130] In the second embodiment, the control system 100 may include either one of the changeover switches QH and QL.

[0131] When the control system 100 is provided with only the positive-side changeover switch QH of the changeover switches QH and QL, in step S30 of Fig. 12, the positive-side changeover switch QH is turned on in the precharge unit 190. In step S33, the positive-side changeover switch QH is turned off in the precharge unit 290.

[0132] When the control system 100 is provided with only the negative side changeover switch QL of the changeover switches QH and QL, in step S30 of Fig. 12, the negative side changeover switch QL is turned on in the precharge unit 190. In step S33, the negative side changeover switch QL is turned off in the precharge unit 290.

[0133] In the third embodiment, the control system 100 may include either one of the changeover switches QH and QL.

[0134] If the control system 100 is provided with only the positive-side changeover switch QH of the changeover switches QH, QL, the process of Fig. 15 can be modified and executed as follows. In step S41, the precharge unit 290 can perform charge control by chopper control of the positive-side changeover switch QH, or by step-down control or zero-axis current control with the positive-side changeover switch QH turned off. In step S44, the precharge unit 290 turns off the positive-side changeover switch QH.

[0135] If the control system 100 is provided with only the negative-side changeover switch QL of the changeover switches QH, QL, the process of Fig. 15 can be modified and executed as follows. In step S41, the pre-charge unit 290 can perform chopper control of the negative-side changeover switch QL as charge control, or can perform zero-axis current control with the negative-side changeover switch QL turned off. In step S44, the pre-charge unit 290 turns off the negative-side changeover switch QL.

[0136] The series connection of the precharge switch and resistor may be connected in parallel to the positive power switch MH instead of being connected in parallel to the negative power switch ML.

[0137] The DC power source is not limited to a battery, and may be, for example, a fuel cell.

[0138] 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.

[0139] 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.

[0140] 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.

[0141] The control device and method described herein may be implemented by a special-purpose computer configured with a processor and memory programmed to execute one or more functions embodied in a computer program. Alternatively, the control device and method described herein may be implemented by a special-purpose computer configured with a processor comprising one or more dedicated hardware logic circuits. Alternatively, the control device and method described herein may be implemented by one or more special-purpose computers configured with a combination of a processor and memory programmed to execute one or more functions and a processor configured with one or more hardware logic circuits. Furthermore, the computer program may be stored in a computer-readable non-transitory tangible recording medium as instructions to be executed by a computer.

[0142] 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 windings (51U, 51V, 51W) of multiple phases, a first inverter (20) having, for the number of phases, first upper arm switches (SUHa, SVHa, SWHa) and first lower arm switches (SULa, SVLa, SWLa) connected in series, 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, for the number of phases, second upper arm switches (SUHb, SVHb, SWHb) and second lower arm switches (SULb, SVLb, SWLb) connected in series, 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, a switching switch (QH, QL) provided on at least one of the positive bus bar and the negative bus bar, a first capacitor (15a) connected in parallel to the series connection of the first upper arm switches and the first lower arm switches, a second capacitor (15b) connected in parallel to the series connection of the second upper arm switches and the second lower arm switches, a power switch (MH, ML) provided in a path electrically connecting the first inverter and the DC power supply, and a series connection of a precharge switch (MP) and a resistor (13) connected in parallel to the power switch. A control device for a rotating electrical machine applied to a system (100), wherein in each phase, the low potential side terminals of the first upper arm switches and the high potential side terminals of the first lower arm switches are electrically connected to the first end of the winding, in each phase, the low potential side terminals of the second upper arm switches and the high potential side terminals of the second lower arm switches are electrically connected to the second end of the winding, and it includes a precharge unit (90, 190, 290) that turns on the precharge switch prior to turning on the power switch, and the precharge unit turns off the switching switch during at least a part of the precharge period from when the precharge switch is turned on until the voltage of the first capacitor reaches a determination voltage.

2. The precharge unit turns off the switching switch during the precharge period, for the control device of the rotating electrical machine according to claim 1.

3. When the precharge unit determines that the voltage of the first capacitor has reached the determination voltage, the precharge unit turns off the precharge switch and turns on the power switch. In a state where the precharge switch is turned off and the power switch is turned on, a charge control unit (80, 86, 91, 181, 191, 291) that performs charge control to supply the output current of the DC power supply to the second capacitor is provided, for the control device of the rotating electrical machine according to claim 2.

4. The charge control unit (91) performs chopper control on the switching switch as the charge control, for the control device of the rotating electrical machine according to claim 3.

5. As a processing unit for performing the charge control, the charge control unit includes: a zero-axis command value calculation unit (191) that calculates a zero-axis current command value, which is a command value of the zero-axis current flowing through the winding of each phase from the first end side to the second end side; a dq-axis command value calculation unit (80) that calculates a d-axis current command value and a q-axis current command value flowing through the winding of each phase based on a torque command value that commands the torque of the rotating electrical machine; a current value calculation unit (181) that calculates a d-axis current value, a q-axis current value, and a zero-axis current value flowing through the winding of each phase; and a switch control unit (86) 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 in a state where the switching switch is turned off to control the calculated d-axis current value, the q-axis current value, and the zero-axis current value to the calculated d-axis current command value, the q-axis current command value, and the zero-axis current command value, for the control device of the rotating electrical machine according to claim 3.

6. The system includes a positive electrode side switching switch (QH) provided on the positive electrode side bus as the switching switch. The charge control unit (291) controls the on / off 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 step down the output voltage of the DC power supply and apply the stepped-down voltage to the second capacitor in a state where the positive electrode side switching switch is turned off as the charge control, for the control device of the rotating electrical machine according to claim 3.

7. The determination voltage is a first determination voltage, and the precharge unit (190) turns on the switching switch during a specific period within the precharge period, from when the precharge switch is turned on until the voltage of the second capacitor reaches a second determination voltage lower than the determination voltage, and turns off the switching switch during a period other than the specific period within the precharge period. The control device for a rotating electrical machine according to claim 1.

8. The determination voltage is a first determination voltage, and the precharge unit (290) performs charge control to supply the output current of the DC power supply to the second capacitor during a specific period within the precharge period, from when the precharge switch is turned on until the voltage of the second capacitor reaches a second determination voltage lower than the determination voltage, and turns off the switching switch during a period other than the specific period within the precharge period. The control device for a rotating electrical machine according to claim 1.

9. The precharge unit executes a process of chopper control of the switching switch as a process for performing the charge control. The control device for a rotating electrical machine according to claim 8.

10. The precharge unit, as a process for performing the charge control, includes a process of calculating a zero-axis current command value, which is a command value of the zero-axis current flowing through the windings of each phase from the first end side to the second end side, a process of calculating a d-axis current command value and a q-axis current command value flowing through the windings of each phase based on a torque command value for commanding the torque of the rotating electrical machine, a process of calculating a d-axis current value, a q-axis current value, and a zero-axis current value flowing through the windings of each phase, and a process 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 in a state where the switching switch is turned off to control the calculated d-axis current value, the q-axis current value, and the zero-axis current value to the calculated d-axis current command value, the q-axis current command value, and the zero-axis current command value. The control device for a rotating electrical machine according to claim 8.

11. The system includes a positive electrode side changeover switch (QH) provided on the positive electrode side busbar as the changeover switch. The precharge unit, as a process for performing the charge control, steps down the output voltage of the DC power supply and applies the stepped-down voltage to the second capacitor in a state where the positive electrode side changeover switch is turned off, and executes a process of controlling the on / off of the first upper arm switch, the first lower arm switch, the second upper arm switch, and the second lower arm switch. The control device for a rotating electrical machine according to claim 8.

12. A rotating electrical machine (40) having a multi-phase winding (51U, 51V, 51W), a first inverter (20) having a number of series-connected first upper arm switches (SUHa, SVHa, SWHa) and first lower arm switches (SULa, SVLa, SWLa) 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, SVHb, SWHb) and second lower arm switches (SULb, SVLb, SWLb) corresponding to the number of phases, 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, a switching switch (QH, QL) provided on at least one of the positive bus bar and the negative bus bar, a first capacitor (15a) connected in parallel to the series connection of the first upper arm switches and the first lower arm switches, a second capacitor (15b) connected in parallel to the series connection of the second upper arm switches and the second lower arm switches, a power switch (MH, ML) provided in a path electrically connecting the first inverter and the DC power supply, and a series connection of a precharge switch (MP) and a resistor (13) connected in parallel to the power switch. A program applied to a system (100), wherein 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 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 winding, and a processor (60a) is caused to execute a precharge process of turning on the precharge switch prior to turning on the power switch, and a process of turning off the switching switch during at least a part of a precharge period from when the precharge switch is turned on until the voltage of the first capacitor reaches a determination voltage.

13. A rotating electrical machine (40) having windings (51U, 51V, 51W) of multiple phases, a first inverter (20) having a number of series-connected first upper arm switches (SUHa, SVHa, SWHa) and first lower arm switches (SULa, SVLa, SWLa) 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, SVHb, SWHb) and second lower arm switches (SULb, SVLb, SWLb) corresponding to the number of phases, 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, a switching switch (QH, QL) provided on at least one of the positive bus bar and the negative bus bar, a first capacitor (15a) connected in parallel to the series connection of the first upper arm switches and the first lower arm switches, a second capacitor (15b) connected in parallel to the series connection of the second upper arm switches and the second lower arm switches, a power switch (MH, ML) provided in the path electrically connecting the first inverter and the DC power supply, and a series connection of a precharge switch (MP) and a resistor (13) connected in parallel to the power switch. A control method for a rotating electrical machine applied to a system (100) 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 being electrically connected to the first end of the 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 being electrically connected to the second end of the winding; a precharge process of turning on the precharge switch prior to turning on the power switch; and a process of turning off the switching switch during at least a part of the precharge period from when the precharge switch is turned on until the voltage of the first capacitor reaches a determination voltage.

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