Motor drive unit

Abstract

To provide an electric motor driving device having a two-inverter configuration in which an output of an electric motor is stabilized and the continuity is maintained at a time of switching between a one-side driving mode and a both-side driving mode.SOLUTION: An electric motor driving device controls driving of an electric motor that has a winding wire to which two inverters connected to a power source are connected. A switching arbitration unit 303 determines switching between a one-side driving mode in which either one of two inverters 60, 70 is switchingly driven and a both-side driving mode in which both the inverters 60, 70 are switchingly driven, and arbitrates outputs of the respective inverters 60, 70 at the switching time so as to continue an output of the electric motor before and after driving mode switching. The switching arbitration unit 303 slightly changes a power amount of the inverter on the driving start side to increase from zero at the switching time from the one-side driving mode to the both-side driving mode, and slightly changes a power amount of the inverter on the driving end side to decrease to zero at the switching time from the both-side driving mode to the one-side driving mode.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to a motor drive device that drives a motor with two inverters.

Background Art

[0002] Conventionally, a technique for driving one AC motor provided between two inverters is known. For example, the inverter system disclosed in Patent Document 1 uses a combination of two different types of power sources (for example, an output type power source and a capacitive type power source), and drives the motor with the more suitable power source according to the operating temperature range. Further, this system considers the states and characteristics of each power source in order to compensate for an instantaneous output decrease of the motor, and switches between single-side power source driving and both-side power source driving.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Patent Document 1 describes switching a drive pattern using either one or both of two power sources having different characteristics based on the drive state of the device and the motor output. However, as an inevitable problem of the two-power-source two-inverter system, a sudden change in the voltage across the motor coil always occurs when switching the drive mode. Patent Document 1 does not mention a specific switching method that can address this problem.

[0005] Each of the two inverters independently outputs voltage pulses, which determine the voltage applied to the motor coils. In other words, if the output of each inverter cannot be controlled to the optimal value required for the motor at that moment, torque fluctuations will be caused by current disturbances resulting from voltage excesses or deficiencies. Furthermore, in the worst case, overcurrents generated by excessive voltage application may lead to component failure. This challenge applies not only to two-power-supply, two-inverter systems, but also to systems in which two inverters are connected to a single common power supply.

[0006] This invention was created in view of the above-mentioned problems, and its purpose is to provide a motor drive device that stabilizes and maintains continuity of the motor output when switching between a single-sided drive mode and a double-sided drive mode in a two-inverter configuration. [Means for solving the problem]

[0007] A motor drive device according to a first aspect (exclusive aspect) of the present invention controls the drive of a motor (80) having windings (81, 82, 83) to which each of two inverters connected to a power supply (11, 12, 13) is connected. This motor drive device comprises a first inverter (60), a second inverter (70), and a control unit (300).

[0008] One of the two inverters, the first inverter, receives DC power from the power supply and has a plurality of first switching elements (61-66) corresponding to each phase of the winding, and is connected to one end of the winding. The other of the two inverters, the second inverter, receives DC power from the power supply and has a plurality of second switching elements (71-76) corresponding to each phase of the winding, and is connected to the other end of the winding.

[0009] The control unit includes two inverter control circuits: a first inverter control circuit (301) that generates a first voltage command, which is an output voltage command to the first inverter, based on a torque command; a second inverter control circuit (302) that generates a second voltage command, which is an output voltage command to the second inverter; and a switching arbitration unit (303). At least one of the inverter control circuits has the function of adjusting the amount of power supplied from the power source to the two inverters.

[0010] The switching arbitration unit determines whether to switch between a "single-sided drive mode," in which one of the two inverters is driven by switching, and a "double-sided drive mode," in which both inverters are driven by switching. Furthermore, it arbitrates the output of each inverter at the time of switching so that the output of the motor is continuous before and after the switch in the drive mode.

[0011] The switching arbitration unit determines whether to switch between single-sided drive mode and double-sided drive mode based on the self-inverter voltage utilization rate, which is calculated by dividing the inverter line voltage by the inverter input voltage for at least one inverter. When the self-inverter voltage utilization rate increases in single-sided drive mode and reaches the double-sided switching threshold, it switches to double-sided drive mode. When the self-inverter voltage utilization rate decreases in double-sided drive mode and reaches the single-sided switching threshold, it switches back to single-sided drive mode. When switching from single-sided drive mode to double-sided drive mode, the switching arbitration unit gradually increases the power of the drive start side inverter from zero. When switching from double-sided drive mode to single-sided drive mode, the switching arbitration unit gradually decreases the power of the drive end side inverter to zero.

[0012] Here, the "inverter that starts the drive" is the inverter that initiates the switching drive from the idle state. The "inverter that ends the drive" is the inverter that terminates the switching drive and transitions to the idle state. Furthermore, "zero" in terms of power is not limited to exactly 0 [W], but includes minute values ​​within a range judged to be near zero based on the common technical knowledge in the relevant field. "Slow change" means a speed change at a level that the feedback control can follow.

[0013] The switching arbitration unit of the present invention maintains continuous motor output before and after switching by gradually changing the power output of each inverter when switching drive modes. This prevents equipment damage caused by torque fluctuations of the motor and overcurrents generated during such fluctuations. Furthermore, it eliminates the effect of power fluctuations caused by operation during drive mode switching, which can cause fluctuations in motor torque.

[0014] A motor drive device according to a second aspect of the present invention is a motor drive device that controls the drive of a motor (80) having windings (81, 82, 83) connected to two inverters connected to a common power supply (13). This motor drive device comprises a first inverter (60), a second inverter (70), a common high-potential side wiring (Pcom), a common low-potential side wiring (Ncom), a switch (14), and a control unit (300).

[0015] One of the two inverters, the first inverter, has a plurality of first switching elements (61-66) corresponding to each phase of the winding and is connected to one end of the winding. The other of the two inverters, the second inverter, has a plurality of second switching elements (71-76) corresponding to each phase of the winding and is connected to the other end of the winding. A common high-potential wiring connects the high-potential wiring (P1, P2) of the first inverter and the second inverter. A common low-potential wiring connects the low-potential wiring (N1, N2) of the first inverter and the second inverter. A switch is provided on at least one of the common high-potential wiring or the common low-potential wiring and is capable of interrupting the current path. The control unit has two inverter control circuits, a first inverter control circuit (301) and a second inverter control circuit (302), similar to those in the first embodiment, and a switching arbitration unit (303). At least one of the inverter control circuits has the function of adjusting the amount of power supplied from a common power source to the two inverters.

[0016] In the second embodiment, the motor drive device is configured in a star connection circuit with one inverter neutral-coupled when the switch is open, and the other inverter can be operated in a single-sided drive mode. Furthermore, in an H-bridge circuit configured with corresponding first and second switching elements for each phase when the switch is closed, it can be operated in a double-sided drive mode.

[0017] A motor drive device according to a third aspect of the present invention controls the drive of a motor (80) having windings (81, 82, 83) to which each of two inverters, each individually connected to a plurality of power sources (11, 12), is connected. This motor drive device comprises a first inverter (60), a second inverter (70), and a control unit (300).

[0018] One of the two inverters, the first inverter, receives DC power from a predetermined number of first power sources (11) connected to it, and has a plurality of first switching elements (61-66) corresponding to each phase of the winding, and is connected to one end of the winding. The other of the two inverters, the second inverter, has a plurality of second switching elements (71-76) corresponding to each phase of the winding, and is connected to the other end of the winding. The control unit has two inverter control circuits, a first inverter control circuit (301) and a second inverter control circuit (302), similar to those in the first embodiment, and a switching arbitration unit (303). At least one of the inverter control circuits has a function to adjust the amount of power supplied from the plurality of power sources to the two inverters.

[0019] In the second and third embodiments, the switching arbitration unit performs a switching determination in the same manner as in the first embodiment and changes the power output of the drive start side inverter and the power output of the drive end side inverter.

[0020] The motor drive devices according to the fourth and fifth aspects of the present invention differ only in the operation of the switching arbitration unit from the motor drive devices according to the second and third aspects, respectively. In a single-side drive mode, the output of the inverter is determined based on the voltage of one of the first power supplies, and in a both-sides drive mode, in a control configuration where the output of each inverter is determined based on the sum of the voltages of a plurality of power supplies, the switching arbitration unit corrects the voltage command to the inverter operating in the single-side drive mode at the time of switching the drive mode and passes it on to the next processing cycle.

Brief Description of the Drawings

[0021] [Figure 1] Overall configuration diagram of a system to which the motor drive device of the first embodiment is applied. [Figure 2] (a) Diagram showing switching drive in a single-side drive mode, (b) both-sides drive mode. [Figure 3] (a) N-T characteristic diagram showing regions to which a single-side drive mode, (b) both-sides drive mode are applied. [Figure 4] Schematic configuration diagram of the control unit of the first embodiment. [Figure 5] Diagram (a) explaining fluctuations in the voltage across the MG coil, (b) schematic control configuration diagram at the time of switching between a single-side drive mode and a both-sides drive. [Figure 6] Flowchart of the drive mode switching process according to the first embodiment. [Figure 7] Control block diagram for executing the drive mode switching process (voltage command instantaneous correction + power amount gradual change) according to the first embodiment. [Figure 8] Sub-flowchart showing a specific example of the switching determination in FIG. 6. [Figure 9] Time chart showing the drive mode switching operation according to a comparative example. [Figure 10] Time chart showing the drive mode switching operation according to the first embodiment. [Figure 11] Diagram explaining the gradual change in the power distribution amount corresponding to the enlarged view of part XI in FIG. 10. [Figure 12] (a) Diagram showing switching determination at the voltage utilization rate used for MG control, (b) diagram showing switching determination at the self-inverter voltage utilization rate. [Figure 13] A time chart showing the operation of the gradual change processing according to the second embodiment. [Figure 14] (a) A diagram illustrating the fluctuation of the voltage across the MG coil when switching from single-sided drive of the first inverter to single-sided drive of the second inverter, and (b) a schematic control configuration diagram. [Figure 15] A control block diagram for executing the drive mode switching process according to the third embodiment. [Figure 16] Flowchart of the drive mode switching process according to the third embodiment. [Figure 17] A time chart showing the switching operation according to the third embodiment when the voltages of the two power supplies are equivalent. [Figure 18] A time chart showing the switching operation according to the third embodiment when the voltages of the two power supplies are different. [Figure 19] An overall configuration diagram of a system to which the motor drive device of the fourth embodiment is applied. [Figure 20] (a) A diagram illustrating the switching drive in one-sided drive mode in a star connection circuit, and (b) a diagram illustrating the switching drive in both-sided drive mode in an H-bridge circuit. [Figure 21] A time chart showing the drive mode switching operation according to the fourth embodiment. [Figure 22] An overall configuration diagram of a system to which the motor drive device of the fifth embodiment is applied. [Figure 23] An overall configuration diagram of a system to which the motor drive device of the sixth embodiment is applied. [Figure 24] A time chart showing the drive mode switching operation according to the sixth embodiment. [Modes for carrying out the invention]

[0022] The following describes several embodiments of the motor drive system based on the drawings. Embodiments 1 to 6 are collectively referred to as "this embodiment." The motor drive system of this embodiment is a device that controls the drive of a three-phase AC motor (MG) in a system that drives a motor generator (hereinafter, "MG"), which is a power source for hybrid vehicles and electric vehicles, using two inverters. In the embodiment, "MG" and "MG control device" correspond to "motor" and "motor drive system."

[0023] The first, fourth, fifth, and sixth embodiments combine differences in the number of power supplies and the winding configuration of the MG in the system to which the MG control device is applied. Regarding the number of power supplies, either two power supplies or one common power supply are used. Regarding the winding configuration of the MG, either an open winding, where the endpoints are not connected (i.e., open), or two sets of windings connected in a star or delta configuration are used. The first embodiment is applied to a system with "two power supplies + open winding," and the fourth embodiment is applied to a system with "one power supply + open winding." The fifth embodiment is applied to a system with "two power supplies + two sets of windings," and the sixth embodiment is applied to a system with "one power supply + two sets of windings."

[0024] The second and third embodiments differ from the first embodiment in that they have a different drive mode switching control in the system configuration. The switching control of the second and third embodiments can also be used in the system configurations of the fourth to sixth embodiments. The first to third embodiments will be described in detail below. For the fourth to sixth embodiments, the technical concepts of the first to third embodiments are applied as is, or with some modifications.

[0025] [System configuration of the first embodiment] Figure 1 shows the overall configuration of the system of the first embodiment, which uses "two power sources and two inverters," that is, two power sources 11 and 12 and two inverters 60 and 70. The system configuration in Figure 1 is also applicable to the second and third embodiments. The MG80 is a permanent magnet synchronous three-phase AC motor having a U-phase winding 81, a V-phase winding 82, and a W-phase winding 83. When applied to a hybrid vehicle, the MG80 functions as an electric motor that generates torque to drive the drive wheels, and as a generator that can generate electricity driven by the kinetic energy of the vehicle transmitted from the engine and drive wheels.

[0026] In the MG80 of the first embodiment, the three-phase windings 81, 82, and 83 are configured as open windings with their endpoints not connected. The output terminals of each phase of the first inverter 60 are connected to one end 811, 821, and 831 of the three-phase open windings 81, 82, and 83, and the output terminals of each phase of the second inverter 70 are connected to the other end 812, 822, and 832 of the three-phase open windings 81, 82, and 83. The rotation angle sensor 85 is composed of a resolver or the like and detects the mechanical angle θm of the MG80. The mechanical angle θm is converted to an electrical angle θe by the electrical angle calculation unit 87 of the control unit 300.

[0027] The first power supply 11 and the second power supply 12 are two independent power supplies that are isolated from each other, and each is a rechargeable energy storage device such as a nickel-metal hydride or lithium-ion secondary battery or an electric double-layer capacitor. For example, the first power supply 11 may use an output-type lithium-ion battery and the second power supply 12 may use a capacity-type lithium-ion battery. The power of power supplies 11 and 12 is expressed as SOC (State of Charge).

[0028] Two inverters 60 and 70 receive DC power individually from two power sources 11 and 12. The first power source 11 can exchange power with the MG80 via the first inverter 60, and the second power source 12 can exchange power with the MG80 via the second inverter 70. The output of the first inverter 60 is equal to the power of the first power source 11, and the output of the second inverter 70 is equal to the power of the second power source 12. The current flowing from the first power source 11 to the first inverter 60 is denoted as the first power source current Ib1, and the current flowing from the second power source 12 to the second inverter 70 is denoted as the second power source current Ib2.

[0029] The MG80 is supplied with power from the first power supply 11 via the first inverter 60, and from the second power supply 12 via the second inverter 70. U-phase voltage VU1, V-phase voltage VV1, and W-phase voltage VW1 are applied to the first inverter 60 side of the three-phase open windings 81, 82, and 83. U-phase voltage VU2, V-phase voltage VV2, and W-phase voltage VW2 are applied to the second inverter 70 side of the three-phase open windings 81, 82, and 83.

[0030] For example, a current sensor 84 is provided in the power path from the first inverter 60 to the MG80 to detect the phase currents supplied to the three-phase open windings 81, 82, and 83. In the example shown in Figure 1, the V-phase current Iv and W-phase current Iw are detected, but any two-phase or three-phase current may be detected. The current sensor 84 may also be provided in the power path from the second inverter 70 to the MG80, or in the paths of both the first inverter 60 and the second inverter 70.

[0031] The first capacitor 16 is connected between the high-potential wiring P1 and the low-potential wiring N1, and the second capacitor 17 is connected between the high-potential wiring P2 and the low-potential wiring N2. The first voltage sensor 18 detects the first power supply voltage VH1 input from the first power supply 11 to the first inverter 60. The second voltage sensor 19 detects the second power supply voltage VH2 input from the second power supply 12 to the second inverter 70. The first power supply voltage VH1 and the second power supply voltage VH2 may be the same or different. The power contribution P_INV1 of the first inverter 60 is expressed as "P_INV1 = Ib1 × VH1", and the power contribution P_INV2 of the second inverter 70 is expressed as "P_INV2 = Ib2 × VH2". The MG80 is supplied with the sum of the powers of the two inverters 60 and 70, "P_INV1 + P_INV2".

[0032] The MG control device 101 comprises a first inverter 60, a second inverter 70, a control unit 300, and drive circuits 67 and 77. The first inverter 60 has six first switching elements 61 to 66 that are bridge-connected and provided corresponding to each phase of the open windings 81, 82, and 83. Switching elements 61, 62, and 63 are upper arm switching elements for the U, V, and W phases, respectively, and switching elements 64, 65, and 66 are lower arm switching elements for the U, V, and W phases, respectively. The second inverter 70 has six second switching elements 71 to 76 that are bridge-connected and provided corresponding to each phase of the open windings 81, 82, and 83. Switching elements 71, 72, and 73 are upper arm switching elements for the U, V, and W phases, respectively, and switching elements 74, 75, and 76 are lower arm switching elements for the U, V, and W phases, respectively.

[0033] Each switching element 61-66, 71-76 is composed of, for example, IGBTs, and has a freewheeling diode connected in parallel that allows current to flow from the low-potential side to the high-potential side. To prevent short circuits between the high-potential side wirings P1, P2 and the low-potential side wirings N1, N2, the upper arm elements and lower arm elements of each phase are controlled to turn on and off complementaryly, rather than simultaneously, that is, when one is on, the other is off.

[0034] The control unit 300 is composed of a microcontroller or the like and includes a CPU, ROM, I / O (not shown), and bus lines connecting these components. The control unit 300 performs software processing by executing a program pre-stored in a physical memory device such as ROM (i.e., a readable non-temporary tangible recording medium) using the CPU, and also performs control through hardware processing using dedicated electronic circuits.

[0035] The control unit 300 receives the torque command trq * The system includes a first inverter control circuit 301 that generates a first voltage command, which is an output voltage command to the first inverter 60, based on the detected value information, and a second inverter control circuit 302 that generates a second voltage command, which is an output voltage command to the second inverter. Each inverter control circuit 301 and 302 receives information such as the electrical angle θe and power supply voltages VH1 and VH2. The first drive circuit 67 outputs a gate signal to the first inverter 60 based on the first voltage command generated by the first inverter control circuit 301. The second drive circuit 77 outputs a gate signal to the second inverter 70 based on the second voltage command generated by the second inverter control circuit 302.

[0036] Temperature sensors 861, 862, 863, 864, and 865 detect the temperature Hb1 of the first power supply 11, the temperature Hb2 of the second power supply 12, the temperature Hinv1 of the first inverter 60, the temperature Hinv2 of the second inverter 70, and the temperature Hmg of the MG 80, respectively, and notify the control unit 300. The temperature of each part is one of the determination factors in the drive mode switching determination described later.

[0037] [Overview of single-sided drive mode and double-sided drive mode] A control mode in which one of the two inverters 60 and 70 is switched-driven is called the "single-sided drive mode," and a control mode in which both inverters 60 and 70 are switched-driven is called the "double-sided drive mode." This embodiment focuses on the switching operation between the single-sided drive mode and the double-sided drive mode. Below, as an example of switching from the single-sided drive mode to the double-sided drive mode, the switching from the single-sided drive mode to the double-sided drive mode by the first inverter 60 will be described. The case of switching from the single-sided drive mode to the double-sided drive mode by the second inverter 70 is similar and will therefore be omitted from the description, but this is not limited to the functional means.

[0038] Figure 2(a) shows the switching drive in the single-sided drive mode, and Figure 2(b) shows the switching drive in the double-sided drive mode. In the single-sided drive mode, only one of the first inverters 60 is switched on. For the second inverter 70, one of the all-phase upper arm switching elements 71, 72, 73 or the all-phase lower arm switching elements 74, 75, 76 is turned on, and the other is turned off, electrically coupling the neutral point. In the double-sided drive mode, both inverters 60 and 70 are switched on, thereby connecting the voltages of the two power supplies 11 and 12 in series.

[0039] Refer to the NT characteristic diagrams in Figures 3(a) and 3(b) for the concept of drive mode switching. The hatched areas in each figure represent the regions where that drive mode is preferred to be applied. The one-sided drive mode shown in Figure 3(a) has the advantage of high efficiency at low loads and the disadvantage of a low upper limit to high load performance, making it advantageous at low loads. The two-sided drive mode shown in Figure 3(b) has the advantage of a high upper limit to high load performance and the disadvantage of low efficiency at low loads, making it advantageous at high loads.

[0040] Therefore, by ensuring sufficient output with a dual-sided drive mode under high load conditions, and switching to a single-sided drive mode for low-loss drive under low load conditions, it is possible to achieve a drive that balances both output and efficiency. In this specification, the verb "to switch" is written with a suffix, while the noun "switching" is written without a suffix.

[0041] [Challenges and points of focus] A fundamental challenge of a dual-power, dual-inverter system is that abrupt changes in the voltage across the MG coil inevitably occur when switching drive modes. In other words, the two inverters 60 and 70 each output voltage pulses independently, and these determine the voltage applied to the MG coil. To put it another way, if the output of each inverter 60 and 70 cannot be controlled to the optimal value required for the MG80 at that moment, torque fluctuations will be caused by current disturbances resulting from voltage excesses or deficiencies. Furthermore, in the worst case, excessive voltage application can lead to overcurrent and component failure.

[0042] Therefore, in the first embodiment, the objective is to ensure that the MG output is stable and continuous before and after the drive mode switching, while adhering to the principle that the desired MG output and each inverter output can be obtained by independently and cooperatively controlling the output of each inverter 60 and 70. More specifically, the following three points are considered.

[0043] [1] The inverter output changes gradually during the rise and fall of the drive mode switchover to prevent abrupt changes. [2] Output fluctuations are eliminated by instantaneous correction of the voltage command, which aims to resolve the factors causing output changes in the self-inverter within the self-inverter. [3] The switching judgment is determined appropriately and uniquely, regardless of the state changes before and after switching, ensuring stable switching at the timing of the desired MG output, thereby achieving both high-output driving and low-loss driving at low output.

[0044] [Configuration of the control unit] Figure 4 shows a schematic configuration of the control unit 300. In the following figures, an inverter is denoted as "INV". The first inverter control circuit 301 and the second inverter control circuit 302 drive the first inverter 60 and the second inverter 70, respectively, by dq control (i.e., vector control in dq axis coordinates). The inverter control circuits 301 and 302 may be provided in separate microcontrollers, or they may be provided in a single common microcontroller. Each inverter control circuit 301 and 302 generates independent and coordinated voltage commands to drive the system as a two-power supply, two-inverter system.

[0045] Since the MG80 is common to the information acquired by the control unit 300, the detected values ​​of the angle (specifically, the electrical angle θe) and the three-phase current can be common. However, as shown by the dashed line, multiple current sensors 84 and rotation angle sensors 85 may be provided, and each inverter control circuit 301, 302 may acquire the corresponding detected values. Also, when the second inverter control circuit 302 performs feedforward control, it does not need to acquire the detected values ​​of the three-phase current, as shown by the dashed line.

[0046] The control unit 300 has a function in which at least one inverter control circuit adjusts the amount of power supplied from two power sources 11 and 12 to two inverters 60 and 70. In the configuration shown in Figure 4, one first inverter control circuit 301 acts as a torque management circuit, achieving torque through feedback control. The other second inverter control circuit 302 acts as a power management circuit, managing power through feedforward control and power distribution control.

[0047] The power management circuit has the function of adjusting the amount of power supplied from the two power sources 11 and 12 to the two inverters 60 and 70. Furthermore, the power distribution control manages the distribution of power supplied from the two power sources 11 and 12 to the two inverters 60 and 70. In the following diagram, "feedback" is denoted as "FB" and "feedforward" as "FF". Note that the roles of the first inverter control circuit 301 and the second inverter control circuit 302 may be swapped.

[0048] In this configuration, the first inverter control circuit 301 corrects disturbance suppression so that the torque follows the command through feedback control, while the second inverter control circuit 302 manages the power of each inverter 60 and 70 through feedback control uniquely determined by the command. In this way, by adjusting the inverter power with the power management circuit and correcting disturbance suppression with feedback control so that the torque management circuit achieves the required torque, the control unit 300 achieves both the desired MG torque and the power of each power supply without control interference.

[0049] Incidentally, since the dq control for driving inverters 60 and 70 by inverter control circuits 301 and 302 is independent, there is a degree of control freedom. However, if the voltage across the MG coil generated by the coordinated commands of each inverter is not optimal for MG80, the MG torque (output) and the power of each inverter will easily fluctuate. This fluctuation becomes even more pronounced in the scene of switching between single-sided drive mode and double-sided drive mode, where the voltage across the MG coil changes most dramatically in a short time.

[0050] Therefore, the control unit 300 of this embodiment has a switching arbitration unit 303 that sets each inverter control circuit 301, 302 to perform torque management and power management roles, determines the switching between single-sided drive mode and double-sided drive mode, and arbitrates the output of each inverter 60, 70 when switching. The switching arbitration unit 303 arbitrates the amount of power change so as not to be affected by the change in voltage across both ends of the MG coil when switching between single-sided drive mode and double-sided drive mode, and makes the MG output continuous before and after switching.

[0051] In the configuration shown in Figure 4, the torque command trq is received from an external higher-level control circuit. * The power distribution request is first input to the switching arbitration unit 303, and then notified to each inverter control circuit 301, 302. However, this configuration is not limited to this one, and external torque commands trq * Alternatively, power distribution requests may be input to each inverter control circuit 301 and 302 before being notified to the switching arbitration unit 303.

[0052] The switching arbitration unit 303 gradually increases the power of the drive start side inverter from zero when switching from a single-side drive mode to a double-side drive mode. Conversely, when switching from a double-side drive mode to a single-side drive mode, the switching arbitration unit 303 gradually decreases the power of the drive end side inverter to zero. The term "zero" for power is not limited to a precise 0[W], but includes minute values ​​within a range judged as "near zero" based on common technical knowledge in this field. This ensures the continuity of the MG output and eliminates control fluctuations, regardless of changes in the voltage across the MG coil.

[0053] Here, the "inverter that starts the drive" is the inverter that starts the switching drive from the current idle state. The "inverter that ends the switching drive that was being performed up to the present and returns to the idle state. When switching from the first inverter's single-sided drive mode to the double-sided drive mode, the second inverter 70 corresponds to the "inverter that starts the drive". Also, when switching from the double-sided drive mode to the first inverter's single-sided drive mode, the second inverter 70 corresponds to the "inverter that ends the drive".

[0054] The specific drive mode switching operations will be described below for each embodiment. In the first and second embodiments, the operation of transitioning from the first inverter single-sided drive mode to the double-sided drive mode, or conversely, from the double-sided drive mode to the first inverter single-sided drive mode, will be described. In the third embodiment, the operation of transitioning from the first inverter single-sided drive mode to the second inverter single-sided drive mode via the double-sided drive mode will be described.

[0055] (First Embodiment) Referring to Figures 5 to 12, the control configuration for switching between the single-sided drive mode and the double-sided drive mode of the first inverter will be described as a first embodiment. As shown in Figure 5(a), the voltage amplitude across the MG coil is the voltage amplitude of one power supply in the single-sided drive mode and the voltage amplitude of two power supplies in the double-sided drive mode. Therefore, the voltage across the MG coil always changes before and after switching between the single-sided drive mode and the double-sided drive mode. This is an inherent challenge of a two-power supply, two-inverter system. If this change in the voltage across the MG coil, which is directly related to the generation of three-phase current, cannot be accommodated, an excess or deficiency will occur in the voltage across the MG coil necessary to generate the desired current, and current disturbances can easily be caused due to the relationship between the electrical circuit and the pulse voltage output.

[0056] Figure 5(b) shows the schematic control configuration when switching between the first inverter's single-sided drive mode and double-sided drive mode. The basic control configuration in Figure 5(b), including the calculation of the current command Idq, the calculation of the voltage command Vdq, and PWM control, is a well-known technique and therefore will not be explained. Hereinafter, the d-axis current command Id and the q-axis current command Iq will be collectively referred to as the current command Idq, and the d-axis voltage command Vd and the q-axis voltage command Vq will be collectively referred to as the voltage command Vdq. Here, the d-axis voltage command Vd is 0 or a negative value, and hereafter, "Vdq increases / decreases" means that the absolute value of the d-axis voltage command Vd and the q-axis voltage command Vq increase / decrease.

[0057] When the first inverter 60 is switched on by itself, the first power supply voltage VH1 is applied as the input voltage for PWM control. On the other hand, when both inverters 60 and 70 are switched on, with the first inverter 60 continuing to switch on while the second inverter 70 begins switching on, the sum of the voltages of the two power supplies (VH1 + VH2) is applied as the input voltage for PWM control. Thus, a switch occurs in the control from the perspective of the motor generator (MG). When the drive mode is switched, if the switching of each inverter 60 and 70 cannot be coordinated, and there is an excess or deficiency of the applied voltage relative to the required voltage, current disturbances occur.

[0058] In the first embodiment, the following switching process is performed to avoid excess or deficiency of applied voltage and to maintain the continuity of the MG output. Next, the drive mode switching process according to the first embodiment will be explained with reference to the flowchart in Figure 6 and the control block diagram in Figure 7. In the following flowchart explanation, the symbol "S" means step. Also, in Figure 7, the first inverter control circuit 301 is assumed to be a torque management circuit, and the second inverter control circuit 302 is assumed to be a power management circuit.

[0059] In S10, the switching arbitration unit 303 makes a switching decision based on the output request to MG80, the SOC status of power supplies 11 and 12, or the temperature of power supplies 11 and 12, inverters 60 and 70, or MG80. A specific example of the switching decision will be described later with reference to Figure 8. In S21, the voltage recognition value is set. In single-sided drive mode, the voltage recognition value is determined by the power supply voltages VH1 and VH2 of each inverter, and in double-sided drive mode, it is determined by the sum of the voltages of the two power supplies (VH1 + VH2).

[0060] In S22, the voltage command Vdq is instantaneously corrected when the drive mode is switched. When switching from the first inverter single-sided drive mode to the first inverter single-sided drive mode, the voltage command Vdq1 is instantaneously corrected according to equation (1.1). When switching from the second-sided drive mode back to the first inverter single-sided drive mode, the voltage command Vdq1 is instantaneously corrected according to equation (1.2).

[0061]

number

[0062] Let me elaborate on the technical significance of instantaneous correction. As is well known, feedback control is a first-order lag system. Furthermore, since the MG80 has a coil, it is a first-order lag system as an electrical circuit. Therefore, it is clear that the response of the MG control that controls the first-order lag system MG80 with the control of a first-order lag system will be first-order lag. Consequently, it can only respond with a first-order lag to sharp changes in the voltage across the MG coil, such as in a two-power supply, two-inverter configuration, i.e., step changes caused by the instantaneous superposition of the output pulse voltages of both inverters 60 and 70. In the first embodiment, this problem is solved by instantaneously correcting the voltage command Vdq. In the second embodiment, this problem is solved by performing a gradual change processing.

[0063] In S23, the voltage command Vdq1 is set as the amount to be carried over to the next control process in order to maintain the continuity of the inverter output and, consequently, the MG output. In the first inverter control circuit 301, which is the torque management circuit, the integral term of the feedback control is reset. In addition, the voltage command Vdq2 is set in the second inverter control circuit 302, which is the power management circuit, for power calculation in feedforward control. In S24, the second inverter control circuit 302 on the power management side gradually changes the amount of power output so as not to disturb the first inverter control circuit 301 on the torque management side.

[0064] The above switching process is further explained by referring to the block diagram in Figure 7. In the instantaneous correction block of the first inverter control circuit 301, the voltage command Vdq1 is instantaneously corrected according to the voltage recognition value only during switching. In the integral term reset block, the carryover amount for the next feedback control is matched only during switching. As a result, the duty cycle INV1_duty commanded to the first inverter 60 is output while maintaining continuity with the pre-switching state even after switching.

[0065] In the power distribution control block of the second inverter control circuit 302, the voltage command Vdq2 is gradually increased from zero at a rate of change that the feedback control of the first inverter control circuit 301 can follow. As a result, a duty cycle INV2_duty with suppressed abrupt changes during switching is commanded to the second inverter 70.

[0066] Next, referring to the subflowchart in Figure 8, we will supplement the details of the switching determination from one-sided drive mode to two-sided drive mode in S10 of Figure 6. In S11, the MG control device 101 is driven in the one-sided drive mode of the first inverter. In S12, it is determined whether the temperature Hb1 of the first power supply 11 is higher than the upper limit of the appropriate range. In S13, it is determined whether the SOC of the first power supply 11 is lower than the lower limit of the appropriate range. If it is determined to be YES in S12 or S13, it is preferable to reduce the load on the first power supply 11, regardless of whether there is a high output requirement. Therefore, the process proceeds to S16, and the switching arbitration unit 303 determines to switch from the one-sided drive mode of the first inverter to the two-sided drive mode.

[0067] In the dual-sided drive mode of S16, it is preferable to select a pattern in which both inverters 60 and 70 are driven in PWM control mode, and to actively adjust the power so that the temperature and state of clock (SOC) of the first power supply 11 fall within an appropriate range. Depending on the temperature of the first power supply 11, output limiting may also be implemented.

[0068] If NO is determined in S12 and S13, S14 determines whether there is a high output requirement for the MG80. If YES is determined in S14, S15 further determines whether there is a requirement for high-efficiency operation. If YES is determined in S15, the process proceeds to S17, where the switching arbitration unit 303 determines whether to switch from the first inverter single-sided drive mode to the double-sided drive mode. In the double-sided drive mode of S17, a pattern is selected in which the inverter with the larger power requirement is driven in square wave control mode and the other inverter is driven in PWM control mode, thereby enabling high-efficiency operation.

[0069] If the result in S14 is YES and in S15 is NO, the process proceeds to S16, and both inverters 60 and 70 are driven in PWM control mode in the dual-sided drive mode. In this case, normal operation, not intentionally efficient operation, is performed according to the torque command and power command. Also, if the result in S14 is NO, the output from the current single-sided drive mode is sufficient, and there is no need to reduce the load on the first power supply 11. Therefore, the process proceeds to S18, and the switching arbitration unit 303 determines not to perform a switching determination to the dual-sided drive mode.

[0070] Regarding the control mode selected in the dual-drive mode, in PWM control mode, multiple pulses corresponding to the carrier frequency are output per electrical cycle based on a comparison between the voltage command and the carrier wave, while in square wave control mode, one pulse is output per electrical cycle. Furthermore, the PWM control mode includes sinusoidal control mode and overmodulation control mode depending on the voltage utilization rate. Since these control modes themselves are well-known technologies, a detailed explanation is omitted. In addition, the means and methods for selecting the control mode are outside the scope of this specification and will not be discussed in detail.

[0071] Next, referring to the time charts in Figures 9 and 10, the switching operation from one-sided drive mode to two-sided drive mode will be explained while comparing the comparative example and the first embodiment. The power supply voltage is the same, and the power distribution ratio is 1:1. In the comparative example shown in Figure 9, no measures are taken to ensure continuity when switching drive modes. On the other hand, in the first embodiment shown in Figure 10, the instantaneous correction and power quantity gradual change described above are implemented as measures to ensure continuity during switching.

[0072] Each figure shows, from top to bottom, the changes in the MG80's torque, rotational speed, MG output, voltage across the MG coil, power supply current, d-axis voltage command Vd, and q-axis voltage command Vq. The MG output is proportional to the product of torque and rotational speed. The power supply voltage recognition values ​​of each inverter control circuit 301 and 302 correspond to the voltage across the MG coil. No specific numerical values ​​other than "0" are shown on the vertical axis of each figure. Quantities other than the d-axis voltage command Vd take values ​​of 0 or positive, while the d-axis voltage command Vd takes values ​​of 0 or negative. The dashed-dotted line in the figure indicates a quantity related to the first inverter, and the dashed-dotted line indicates a quantity related to the second inverter. The same applies to the following time chart showing the switching operation.

[0073] In both Figures 9 and 10, the drive mode switches from the first inverter single-sided drive mode to the double-sided drive mode, and then back to the first inverter single-sided drive mode. Consequently, the amplitude of the voltage across the MG coil switches from the first power supply voltage VH1 to the sum of the two power supply voltages (VH1 + VH2), and then back to the first power supply voltage VH1.

[0074] In the first inverter's single-sided drive mode, only the first power supply current Ib1 flows, and the second power supply current Ib2 is 0. Therefore, the sum of the power supply currents is "Ib1 + Ib2 = Ib1". In the double-sided drive mode, the sum of the currents from the two power supplies (Ib1 + Ib2) flows. Also, in the first inverter's single-sided drive mode, the first voltage command Vdq1 takes a non-zero value, and the second voltage command Vdq2 is 0. In the double-sided drive mode, the first voltage command Vdq1 and the second voltage command Vdq2 take equivalent non-zero values.

[0075] When switching drive modes, the voltage across the MG coil changes in steps. In the comparative example where no measures are taken to ensure continuity, the voltage commands Vdq1 and Vdq2 change abruptly, causing fluctuations in torque and power as shown in section (Xc). In other words, the torque and power change discontinuously. In contrast, in the first embodiment, the first voltage command Vdq1 is instantaneously corrected in response to the step change in the voltage across the MG coil, and the second voltage command Vdq2 changes accordingly. Furthermore, since the amount of power in the MG output changes gradually, fluctuations in torque and power do not occur when switching drive modes, as shown in section (Xp). Therefore, the torque and power change while maintaining continuity.

[0076] The switching operation of the drive mode in Figure 10 will be explained in the order of numbers 1 to 8. In operation 1, the first inverter 60 is driven on one side. In operation 2, based on the switching determination, the power supply voltage recognition value is switched from VH1 to (VH1 + VH2). In operation 3, the voltage command Vdq1 of the first inverter 60 is instantaneously corrected based on the power supply voltage recognition values ​​before and after the switching.

[0077] Then, based on the value indicated by (*), the value to be carried over to the next integration period is set as the integral term. For example, if there is an addition term other than the feedback control, processing such as subtracting that value and carrying it over is performed so that the integral term can maintain continuity between control periods. The carried-over value has the same effect as the PI integral term. In operation 4, the switching arbitration unit 303 gradually increases the output of the second inverter 70 from zero so that the first inverter 60 can respond.

[0078] In operation 5, the first inverter 60 and the second inverter 70 are driven on both sides. In operation 6, the switching arbitration unit 303 gradually reduces the output of the second inverter 70 to zero so that the first inverter 60 can respond. In operation 7, based on the switching determination, the power supply voltage recognition value is switched from (VH1 + VH2) to VH1. In operation 8, based on the power supply voltage recognition value, the voltage command Vdq1 of the first inverter 60 is instantaneously corrected. Then, the value set based on the voltage command Vdq1 applied immediately after switching from the single-side drive mode is carried over to the next integration cycle.

[0079] Furthermore, Figure 11 shows the change in power distribution between inverters 60 and 70 in the MG output when the drive mode is switched. In the stable stage of the first inverter's single-sided drive mode, the first inverter 60 accounts for 100% of the power. In the power quantity change stage, the power shared by the second inverter 70 gradually increases. In the stable stage of the double-sided drive mode, the distribution ratio between the first inverter 60 and the second inverter 70 becomes constant.

[0080] [Method for determining whether to switch between single-sided drive mode and double-sided drive mode] Next, we will describe a drive mode switching determination method that can accurately (i.e., reliably) and uniquely determine when the MG output reaches the target output. Regarding the voltage utilization rate, which is a prerequisite for switching determination, we will first describe the voltage utilization rate in a typical single-power-supply, single-inverter configuration.

[0081] <1 power supply, 1 inverter configuration> As a drive mode switching request, switching requests can be expected depending on the purpose and scene, such as power supply status (e.g., SOC), power supply, inverter or MG temperature, and MG output status (e.g., voltage utilization rate). Of these factors, the voltage utilization rate, which is an indicator representing the MG output status, is calculated using the following formula. The line voltage amplitude corresponds to the peak value of the fundamental wave amplitude. Also, the inverter input voltage is equal to the power supply voltage VH. Voltage utilization rate = Inverter line voltage amplitude / Inverter input voltage

[0082] Here, if we denote the voltage utilization rate as VUF, the conversion coefficient as K, and the dq-axis voltage amplitude as |Vdq|, the above equation can be expressed as equation (2). Note that the conversion coefficient K is uniquely determined by the way the voltage utilization rate is expressed, so it is omitted in the following equations, including Figure 12.

[0083]

number

[0084] <2 power supply, 2 inverter configuration> In a dual-power supply, dual-inverter configuration with a dual-sided drive mode, the "voltage utilization rate used for MG control" is calculated for each inverter by dividing the inverter line voltage by the sum of the two power supply voltages, as shown in the formula below. Voltage utilization rate used for MG control = Inverter line voltage / Sum of 2 power supply voltages

[0085] The voltage utilization rate used for MG control is the voltage utilization rate from the MG's perspective, which is used to understand the control state, and will be denoted as "VUF_MG" below. The voltage utilization rates VUF_MG_INV1 and VUF_MG_INV2 used for MG control of each inverter are expressed by equations (3.1) and (3.2), using the dq axis voltages Vdq1 and Vdq2.

[0086]

number

[0087] Figure 12(a) shows the operation of the switching determination using the voltage utilization rate VUF_MG used for MG control. In the first inverter single-side drive mode, when the first inverter voltage utilization rate VUF_MG_INV1 rises and reaches the double-side switching threshold, the system switches to the double-side drive mode. At this time, the second inverter voltage utilization rate VUF_MG_2 increases stepwise from 0, and the first inverter voltage utilization rate VUF_MG_INV1 decreases stepwise.

[0088] In dual-side drive mode, the voltage utilization rates of both inverters, VUF_MG_INV1 and VUF_MG_INV2, increase together, reach their upper limit, and then decrease together. Subsequently, when the voltage utilization rates of both inverters, VUF_MG_INV1 and VUF_MG_INV2, reach the single-side switching threshold, the system switches to the first inverter's single-side drive mode.

[0089] Furthermore, we will explain a switching determination method using "self-inverter voltage utilization rate VUF_self" as a separate voltage utilization rate. The self-inverter voltage utilization rate is calculated for each inverter by dividing the inverter line voltage by the input voltage of each inverter, as shown in the formula below. Self-inverter voltage utilization rate = Inverter line voltage / Inverter input voltage

[0090] Hereafter, the symbol for the self-inverter voltage utilization rate will be "VUF_self". The self-inverter voltage utilization rates VUF_self_INV1 and VUF_self_INV2 of each inverter are expressed by equations (4.1) and (4.2), using the dq-axis voltages Vdq1 and Vdq2.

[0091]

number

[0092] For example, when operating to the limit of the single-sided drive mode, the upper threshold of the self-inverter voltage utilization rate VUF_self represents the limit of output from switching drive by a single inverter. In other words, by using the self-inverter voltage utilization rate VUF_self to determine the switching timing, it is possible to determine whether or not the desired output can be obtained by a single inverter. Therefore, by comparing the self-inverter voltage utilization rate VUF_self with a threshold that reflects the desired voltage utilization rate, the switching timing between single-sided drive mode and double-sided drive mode can be determined for the MG output state.

[0093] This method allows for accurate determination of whether the target switching point has been reached, even if variations in equipment constants occur due to sensor errors or changes in MG magnetic flux due to temperature characteristics. Furthermore, it is preferable to provide hysteresis in the threshold used for switching from single-sided drive mode to double-sided drive mode and the threshold used for switching from double-sided drive mode to single-sided drive mode to prevent switching hunting.

[0094] Figure 12(b) shows the operation of the switching determination using the self-inverter voltage utilization rate VUF_self. In the first inverter single-sided drive mode, where "VH2=0", the first inverter's self-inverter voltage utilization rate VUF_self_INV1 is equal to the voltage utilization rate VUF_MG_INV1. When the self-inverter voltage utilization rate VUF_self_INV1 increases and reaches the double-sided switching threshold, the system switches to double-sided drive mode. At this time, the first inverter's self-inverter voltage utilization rate VUF_self_INV1 increases in steps.

[0095] The operation of the voltage utilization rates VUF_MG_INV1 and VUF_MG_INV2 in the dual-sided drive mode is the same as in Figure 12(a). Even if the voltage utilization rates VUF_MG_INV1 and VUF_MG_INV2 of both inverters fall below the upper limit, it does not affect the switching decision. When the self-inverter voltage utilization rate VUF_self_INV1 reaches the single-sided switching threshold, the system switches to the first inverter single-sided drive mode.

[0096] <Effects and Effects> (1) The switching arbitration unit 303 of the first embodiment arbitrates the outputs of each inverter 60 and 70 during switching so that the MG output is continuous before and after the switching of the drive mode. As a result, the MG control device 101 can stabilize and maintain continuity of the MG output when switching between the single-sided drive mode and the double-sided drive mode in a two-power supply, two-inverter configuration. Furthermore, it is possible to prevent component failure due to overcurrent caused by excessive voltage application.

[0097] (2) Specifically, when switching from a single-sided drive mode to a double-sided drive mode, the switching arbitration unit 303 gradually increases the power of the drive start side inverter from zero. Also, when switching from a double-sided drive mode to a single-sided drive mode, the switching arbitration unit 303 gradually decreases the power of the drive end side inverter to zero. This mitigates the output changes of the inverter during the rise and fall of the drive mode switching, and eliminates fluctuations in the motor torque due to power fluctuations.

[0098] (3) The switching arbitration unit 303 makes a switching determination according to the output request to MG80, the SOC status of power supplies 11 and 12, or the temperature of power supplies 11 and 12, inverters 60 and 70, or MG80. This makes it possible to determine whether or not to switch the drive mode according to the drive state.

[0099] (4) The switching arbitration unit 303 determines whether to switch between one-sided drive mode and two-sided drive mode based on the self-inverter voltage utilization rate VUF_self, which is calculated by dividing the inverter line voltage by the inverter input voltage for at least one inverter. This makes it possible to set a switching threshold regardless of the power supply voltage difference and to perform the switching determination uniquely.

[0100] (5) According to the first embodiment, in the single-sided drive mode, the output of the inverter is determined based on the voltage of one power supply, and in the double-sided drive mode, the output of each inverter is determined based on the voltage sum of the two power supplies. The switching arbitration unit 303 instantaneously corrects the voltage command Vdq1 in response to a sudden change in the voltage sum of the two power supplies when the drive mode is switched, and carries it over to the next processing cycle. As a result, the first embodiment can suppress the effects of sudden voltage changes when the drive mode is switched and realize stable inverter drive.

[0101] (Second Embodiment) Next, with reference to Figure 13, the second embodiment will be described. Similar to the first embodiment, the second embodiment has a control configuration in which, in the single-sided drive mode, the output of the inverter is determined based on the voltage of one power supply, and in the double-sided drive mode, the output of each inverter is determined based on the voltage sum of the two power supplies. In the second embodiment, as a response means to step changes due to the instantaneous superposition of the output pulse voltages of inverters 60 and 70 when switching drive modes, the switching arbitration unit 303 performs a "gradual change processing" that gradually changes the voltage recognition value for control in response to abrupt changes in the sum of the two power supply voltages.

[0102] Specifically, in the slow change processing, the amount of change per unit time of the power supply voltage recognition value is limited by an arbitrary time constant delay filter and rate processing. In other words, while the first embodiment performs instantaneous voltage correction, the second embodiment suppresses output fluctuations by performing continuous voltage correction.

[0103] Figure 13 shows the operation of the gradual transition process when the first inverter transitions from single-sided drive mode to double-sided drive mode, and when it transitions from double-sided drive mode back to single-sided drive mode. The first inverter 60 performs gradual transition processes 1 and 4, while the second inverter 70 performs gradual transition processes 2 and 3.

[0104] When switching from the first inverter's single-sided drive mode to the double-sided drive mode, in operation 1, the switching arbitration unit 303 switches the power supply voltage recognition value of the first inverter 60 from VH1 to (VH1 + VH2) by a gradual change process. In operation 2, the switching arbitration unit 303 gradually increases the output of the second inverter 70 at startup by a gradual change process, starting from zero. Accordingly, the output of the first inverter 60 responds smoothly, transitioning to a stable double-sided drive mode.

[0105] When switching from the dual-sided drive mode to the first inverter single-sided drive mode, in operation 3, the switching arbitration unit 303 switches the power supply voltage recognition value of the second inverter 70 from (VH1 + VH2) to VH1 by a gradual change process. In operation 4, the switching arbitration unit 303 gradually reduces the output of the second inverter 70 at the falling edge to zero by a gradual change process. Accordingly, the output of the first inverter 60 is made to respond smoothly, thereby transitioning to a stable single-sided drive mode. Therefore, the second embodiment can suppress the effects of sudden voltage changes during drive mode switching and achieve stable inverter drive.

[0106] (Third embodiment) Next, referring to Figures 14 to 18, a control configuration for switching from a one-sided drive mode using one inverter to a one-sided drive mode using the other inverter will be described as a third embodiment. For example, if only one power source is used continuously in a one-sided drive mode at low load, the power consumption will be uneven, and the power source temperature will rise. If the power source is a battery, the State of Charge (SOC) will be uneven, and there is a risk of depletion. Therefore, it is effective to switch the power source by suspending the inverter that is currently operating in one-sided drive mode and instead driving the inverter that was previously suspended in one-sided drive mode.

[0107] In switching from the first inverter's single-sided drive mode to the second inverter's single-sided drive mode, regardless of the control method, the voltage across the MG coil inevitably changes before and after the switch due to differences in power supply voltage and various variations in the inverters and other components. This is an inherent challenge of a two-power supply, two-inverter system. If this change in the voltage across the MG coil, which is directly related to the generation of three-phase current, cannot be accommodated, an excess or deficiency in the voltage across the MG coil necessary to generate the desired current will occur, easily leading to current disturbances due to the relationship between the electrical circuit and the pulse voltage output.

[0108] As shown in Figure 14(a), the voltage amplitude across the MG coil is the voltage amplitude VH1 of the first power supply 11 when the first inverter is driven on one side, and the voltage amplitude VH2 of the second power supply 12 when the second inverter is driven on one side. Here, the ratio of the voltages of the two power supplies is denoted as "α", which is the ratio of the second power supply voltage VH2 to the first power supply voltage VH1. For example, if the first power supply voltage VH1 is 200V and the second power supply voltage VH2 is 400V, then α is 2.

[0109] Figure 14(b) shows the schematic control configuration when switching between the first inverter single-side drive mode and the second inverter single-side drive mode. When the first inverter 60 is switched on alone, the first power supply voltage VH1 is applied as the input voltage for PWM control. On the other hand, when the second inverter 70 is switched on alone, the second power supply voltage VH2 is applied as the input voltage for PWM control. Therefore, if there is an excess or deficiency of the applied voltage relative to the voltage immediately before the switch when switching drive modes, the inverter output will not be properly taken over, and current disturbances will occur.

[0110] Therefore, in the third embodiment, in order to eliminate power supply voltage differences and machine-specific variations, a double-sided drive mode is passed between the switching between the first inverter single-sided drive mode and the second inverter single-sided drive mode. During the double-sided drive mode, each inverter control circuit 301 and 302 generates inverter voltage commands Vdq1 and Vdq2 that take into account power supply voltage differences and machine-specific variations.

[0111] Figure 15(a) shows, as an example, the control configuration when switching from the first inverter's single-sided drive mode to the second inverter's single-sided drive mode. When switching from the first inverter's single-sided drive mode to the double-sided drive mode, the voltage command Vdq1 of the first inverter 60 is multiplied by (VH1+VH2) / VH1 (=1+α), which is the ratio of the voltage recognition values ​​before and after the switch, due to instantaneous correction of the power supply voltage recognition value.

[0112] During the dual-sided drive mode, power distribution control is performed to gradually change the power output of each first inverter 60. At the start of the dual-sided drive mode, the voltage command Vdq1 of the first inverter 60 is equal to the MG output, and the voltage command Vdq2 of the second inverter 70 is 0. At the end of the dual-sided drive mode, the voltage command Vdq1 of the first inverter 60 becomes 0, and the voltage command Vdq2 of the second inverter 70 becomes equal to the MG output. Output arbitration is performed during this time.

[0113] When switching from the dual-side drive mode to the single-side drive mode of the second inverter, the power supply voltage recognition value is instantaneously corrected, and the ratio of the voltage recognition values ​​before and after the switch, VH2 / (VH1+VH2), is multiplied and inherited as the voltage command Vdq2 of the second inverter 70. The value of this ratio is converted as shown in equation (5).

[0114]

number

[0115] Thus, when switching from a single-sided drive mode by one inverter to a single-sided drive mode by the other inverter, the switching arbitration unit 303 takes over the voltage command Vdq2 of the drive-starting inverter, which is the value obtained by multiplying the voltage command Vdq1 output by the drive-ending inverter by a correction coefficient based on the voltage ratio α of the two power supplies.

[0116] Furthermore, as shown in Figure 15(b), the switching arbitration unit 303 gradually reduces the output (i.e., the amount of power it is handling) of the first inverter 60 on the drive termination side from 100% to 0% during the drive-end mode, and gradually increases the output of the second inverter 70 on the drive start side from 0% to 100%, thereby transferring the amount of power. At this time, the power is gradually changed at a rate of change that the feedback control can follow. When the output of the first inverter 60 decreases to 0%, the switching arbitration unit 303 puts the first inverter 60 into a hiatus.

[0117] Referring to the flowchart in Figure 16, the drive mode switching process according to the third embodiment will be explained. In Figure 16, the steps corresponding to the steps in Figure 6 will be omitted from explanation as appropriate. The switching determination from one-sided drive mode to two-sided drive mode in S10, and the processes from voltage recognition value setting to power quantity variation in S21 to S24 are basically the same as in Figure 6.

[0118] In the switching determination in S10, the switching arbitration unit 303 determines whether to shut down the first inverter 60, which is currently driving on one side, and instead drive the inverter that was previously shut down on one side, if, for example, the temperature Hb1 of the first power supply 11 rises excessively. Here, "when the temperature rises excessively" refers to a case where the temperature exceeds the allowable upper limit, which is even higher than the upper limit of the appropriate range shown in S12 of Figure 8. In this case, it is preferable not only to reduce the load on the first power supply 11 in the dual-drive mode, but also to more actively shut down the first inverter 60. It is also preferable to take similar measures if the temperature Hinv1 of the first inverter 60 rises excessively.

[0119] Furthermore, if the SOC of the first power supply 11 falls below an allowable lower limit that is even lower than the appropriate lower limit shown in S13 of Figure 8, the switching arbitration unit 303 preferably switches to the second inverter single-sided drive mode instead of remaining in the dual-sided drive mode, thereby putting the first inverter 60 into hiatus.

[0120] In S25, the switching arbitration unit 303 is configured to switch between the roles of the torque management circuit and the power management circuit, which are controlled by two inverter control circuits 301 and 302. As described above, the torque management circuit performs feedback control. The power management circuit performs power distribution control based on feedforward control and manages the distribution of power supplied from the two power sources 11 and 12 to the two inverters 60 and 70.

[0121] When an inverter control circuit switches from feedback control to feedforward control, it inherits the value of the integral term as the initial value for power control, and starts power control from that point. Similarly, when an inverter control circuit switches from feedforward control to feedback control, it inherits the voltage command used for power control to the feedback control, substitutes it into the integral term, and starts feedback control using this as the initial value.

[0122] In S30, similar to S10, a determination is made to switch from the dual-sided drive mode to the single-sided drive mode. If the switching determination is successful and S30 determines YES, then in S41 to S44, the processes from voltage recognition value setting to power quantity variation are performed, similar to S21 to S24. Also, in S45, similar to S25, the roles of the two inverter control circuits 301 and 302 are set.

[0123] The time chart in Figure 17 shows the switching operation from driving one side of the first inverter to driving one side of the second inverter when the voltages of the two power supplies are equivalent (i.e., α=1), and this switching operation is explained for each of the nine time periods numbered 1 to 9. In operation 1, the first inverter 60 is driven on one side. In operation 2, based on the switching determination, the power supply voltage recognition value is switched from VH1 to (VH1+VH2). In operation 3, based on the power supply voltage recognition value, the voltage command Vdq1 of the first inverter 60 is instantaneously corrected. In operation 4, the switching arbitration unit 303 gradually increases the output of the second inverter 70 from zero so that the first inverter 60 can respond.

[0124] In operation 5, the first inverter 60 and the second inverter 70 are driven on both sides. In operation 6, the switching arbitration unit 303 gradually increases the output of the second inverter 70 up to 100% so that the first inverter 60 can respond. In operation 7, based on the switching determination, the power supply voltage recognition value is switched from VH1 to (VH1 + VH2) to VH2.

[0125] In operation 8, instantaneous correction based on the power supply voltage recognition value is performed, and the voltage command Vdq1 output by the first inverter 60 is multiplied by a correction coefficient based on the voltage ratio α of the two power supplies, and this value is inherited as the voltage command Vdq2 of the second inverter 70. In operation 9, the control method of the second inverter control circuit 302 is switched from feedforward control-based power control to a feedback control method.

[0126] The timing chart in Figure 18 shows the switching operation from driving one side of the first inverter to driving one side of the second inverter when the voltages of the two power supplies are different. In this example, the voltage of the second power supply VH2 is higher than the voltage of the first power supply VH1, and the voltage ratio α of the two power supplies is greater than 1. Also, the power distribution ratio is 1:1. The timing numbers 1 to 9 for each operation are the same as in Figure 17, and only the differences from Figure 17 will be explained.

[0127] When switching from the first inverter's single-sided drive mode to the double-sided drive mode in operation 2, the difference between the voltage recognition values ​​VH1 and (VH1 + VH2) before and after the switch is large. Therefore, the change in the voltage command Vdq1 from the MG's perspective due to the instantaneous correction in operation 3 appears relatively large. When switching from the double-sided drive mode to the second inverter's single-sided drive mode in operation 7, the difference between the voltage recognition values ​​(VH1 + VH2) and VH2 before and after the switch is small. Therefore, the change in the voltage command Vdq2 from the MG's perspective due to the instantaneous correction in operation 8 appears relatively small. At this time, the value obtained by multiplying by a correction coefficient based on the voltage ratio α of the two power supplies is carried over as the voltage command Vdq2 of the second inverter 70.

[0128] The third embodiment, like the first embodiment, can eliminate output fluctuations when switching drive modes, and can prevent only one power supply from becoming depleted when a low-load, low-loss single-sided drive mode is maintained.

[0129] Furthermore, at least one inverter control circuit operates as a power management circuit, and the switching arbitration unit 303, when switching drive modes, swaps the roles of the power management circuits between the two inverter control circuits 301 and 302, and also transfers the previous control state to the other side. This allows the inverter control circuit responsible for power distribution in both drive modes to be fixed, reducing the number of state transitions and simplifying the configuration.

[0130] The same applies to the first and second embodiments described above, where the roles of the power management circuits are swapped between the two inverter control circuits 301 and 302. In other words, the roles of the torque management circuit and the power management circuit may be swapped when switching from the first inverter single-sided drive mode to the double-sided drive mode, and when switching from the double-sided drive mode to the first inverter single-sided drive mode.

[0131] (Fourth Embodiment) Next, the fourth embodiment will be described with reference to Figures 19 to 21. Figure 19 shows the overall configuration of a system to which the MG control device 104 of the fourth embodiment is applied. In this system, two inverters 60 and 70 are connected to a single common power supply 13. The reference numerals for the capacitor 16, voltage sensor 18, and temperature sensor 861 provided in relation to the common power supply 13 are the same as those for the components corresponding to the first power supply 11 in the first embodiment. The voltage sensor 18 detects the voltage VH of the common power supply 13, and the temperature sensor 861 detects the temperature Hb of the common power supply 13. The current flowing through the common power supply 13 is denoted as the common power supply current Ib. The power Pb of the common power supply 13 is expressed as "Pb = Ib × VH".

[0132] The high-potential side wirings P1 and P2 of the first inverter 60 and the second inverter 70 are connected by a common high-potential side wiring Pcom, and the low-potential side wirings N1 and N2 are connected by a common low-potential side wiring Ncom. In addition, a switch 14 capable of interrupting the current path is provided on at least one of the common high-potential side wiring Pcom or the common low-potential side wiring Ncom. In the example in Figure 19, the switch 14 is provided on the common high-potential side wiring Pcom.

[0133] Similar to Figure 1 of the first embodiment, current Ib1 flows through the first inverter 60 and current Ib2 flows through the second inverter 70. However, in the fourth embodiment, "Ib1" does not mean the current of the first power supply, but rather the "input current of the first inverter." Similarly, "Ib2" does not mean the current of the second power supply, but rather the "input current of the second inverter."

[0134] The sum of the power P_INV1 shared by the first inverter 60 and the power P_INV2 shared by the second inverter 70 is approximately equal to the power Pb of the common power supply 13, although there may be some difference when considering losses due to wiring, etc. That is, it can be expressed as "Pb ≈ P_INV1 + P_INV2". Using current and voltage, it can be expressed as "Ib × VH ≈ Ib1 × VH + Ib2 × VH".

[0135] The configuration of the control unit 300 is basically the same as in the first embodiment. However, in the first embodiment, at least one inverter control circuit has the function of adjusting the amount of power supplied to the two inverters 60 and 70 "from two power sources 11 and 12", whereas in the fourth embodiment, it adjusts the amount of power supplied to the two inverters 60 and 70 "from a common power source 13". In this case, the shared power P_INV1 and P_INV2 are adjusted by adjusting the input currents Ib1 and Ib2 to each inverter 60 and 70.

[0136] The MG control device 104 can operate the other inverter in a single-sided drive mode in a star-connected circuit, which is configured by neutral-point coupling of one inverter, when the switch 14 is open (i.e., off). Furthermore, when the switch 14 is closed (i.e., on), the MG control device 104 can operate in a double-sided drive mode in an H-bridge circuit, which is configured by the corresponding first switching elements 61-66 and second switching elements 71-76 for each phase. This technique of switching between a star-connected circuit and an H-bridge circuit by operating the switch 14 is disclosed in Japanese Patent Application Publication No. 2017-175747, etc.

[0137] Figure 20(a) shows switching drive in one-sided drive mode in a star connection circuit. For example, by turning on one of the upper arm switching elements 71, 72, 73 or the lower arm switching elements 74, 75, 76 of all phases of the second inverter 70 and turning off the other, neutral point coupling is achieved, and a star connection circuit with three phase windings 81, 82, 83 is formed. The first inverter 60 is then driven in one-sided drive mode.

[0138] Figure 20(b) shows the switching drive in the bidirectional drive mode for the H-bridge circuit. For the U-phase open winding 81, the H-bridge circuit is formed by the switching elements 61 and 64 of the first inverter 60 and the switching elements 71 and 74 of the second inverter 70. For the V-phase open winding 82, the H-bridge circuit is formed by the switching elements 62 and 65 of the first inverter 60 and the switching elements 72 and 75 of the second inverter 70. For the W-phase open winding 83, the H-bridge circuit is formed by the switching elements 63 and 66 of the first inverter 60 and the switching elements 73 and 76 of the second inverter 70. When the H-bridge circuits of each phase are driven in bidirectional drive mode, twice the common power supply voltage VH is applied to MG80.

[0139] The time chart in Figure 21 shows the drive mode switching operation according to the fourth embodiment. Similar to Figure 10 of the first embodiment, the drive mode switches from the first inverter single-side drive mode to the double-side drive mode, and then switches again from the double-side drive mode to the first inverter single-side drive mode. The changes in torque, rotational speed, and MG output of the MG80 are the same as in Figure 10. On the other hand, regarding the amplitude of the voltage across the MG coil, the first power supply voltage VH1 in Figure 10 is replaced by the common power supply voltage VH, and the sum of the voltages of the two power supplies (VH1 + VH2) is replaced by twice the common power supply voltage (VH × 2).

[0140] Furthermore, while the change profile itself is the same as in Figure 10 for the power supply current, Figure 21 shows the change in inverter input current, or the change in inverter power distributed proportional to the input current, instead of the power supply current. The sum of the currents of the two power supplies (Ib1 + Ib2) in Figure 10 is replaced by the common power supply current Ib. The sum of the power distributed by the two inverters 60 and 70 (P_INV1 + P_INV2) changes in proportion to the change in the common power supply current Ib. The instantaneous correction of the voltage commands Vdq1 and Vdq2 when switching drive modes is the same as in Figure 10 and is therefore omitted.

[0141] In this switching control, the MG control device 104 determines the output of one inverter (for example, the first inverter 60) based on the common power supply voltage VH in the one-sided drive mode, and determines the output of each inverter 60 and 70 based on twice the common power supply voltage (VH × 2) in the two-sided drive mode. The switching arbitration unit 303 instantaneously corrects the voltage commands Vdq1 and Vdq2 in response to a sudden change in the voltage used to determine the inverter output when the drive mode is switched, i.e., a sudden change from VH to (VH × 2) or from (VH × 2) to VH, and carries over to the next processing cycle.

[0142] Furthermore, the gradual change processing according to the second embodiment may be combined with the switching control described above in the fourth embodiment. In that case, the switching arbitration unit 303 performs "gradual change processing" when switching drive modes, which gradually changes the control voltage recognition value in response to abrupt changes in the voltage used to determine the output of the inverter.

[0143] In this fourth embodiment, a system that drives MG80 with open windings 81, 82, and 83 using one common power supply 13 and two inverters 60 and 70 switches between a one-sided drive mode in a star connection circuit and a two-sided drive mode in an H-bridge circuit. When switching drive modes, the power P_INV1 and P_INV2 shared by each inverter 60 and 70 are output arbitrated according to the drive mode after the switch.

[0144] This allows for stable shutdown of one inverter in the low-power MG drive range, thereby reducing losses. Furthermore, if the thermal load on one inverter is high in single-sided or double-sided drive mode, the thermal load can be distributed by stably shutting down one inverter or switching to double-sided drive mode.

[0145] Furthermore, the switching arbitration unit 303 of the fourth embodiment provides the same effects as those (2) to (4) of the first embodiment. Specifically, when switching from a single-sided drive mode to a double-sided drive mode, the switching arbitration unit 303 gradually increases the power of the drive start side inverter from zero. Also, when switching from a double-sided drive mode to a single-sided drive mode, the switching arbitration unit 303 gradually decreases the power of the drive end side inverter to zero. This mitigates the output changes of the inverter during the rise and fall of the drive mode switching, and eliminates fluctuations in the motor torque due to power fluctuations.

[0146] Furthermore, the switching arbitration unit 303 makes a switching determination based on the output request to the MG80, the SOC status of the common power supply 13, or the temperature of the common power supply 13, inverters 60, 70, or MG80. This makes it possible to determine whether or not to switch the drive mode according to the drive state.

[0147] Furthermore, the switching arbitration unit 303 determines whether to switch between one-sided drive mode and two-sided drive mode based on the self-inverter voltage utilization rate VUF_self, which is calculated by dividing the inverter line voltage by the inverter input voltage for at least one inverter. This makes it possible to set a switching threshold regardless of the power supply voltage difference and to perform the switching determination uniquely.

[0148] Furthermore, in the fourth embodiment, as in the above embodiments, at least one inverter control circuit operates as a power management circuit. In this case, the switching arbitration unit 303 can swap the roles of the power management circuits between the two inverter control circuits 301 and 302 when the drive mode is switched, and can also transfer the previous control state to the other side.

[0149] (Fifth embodiment) Next, a fifth embodiment will be described with reference to Figure 22. Figure 22 shows the overall configuration of a system to which the MG control device 105 of the fifth embodiment is applied. In this system, similar to the first embodiment shown in Figure 1, the first inverter 60 is connected to the first power supply 11, and the second inverter 70 is connected to the second power supply 12. The meanings of the first power supply current Ib1, the second power supply current Ib2, the first power supply voltage VH1, and the second power supply voltage VH2 are interpreted in accordance with the first embodiment.

[0150] The MG90 of the fifth embodiment is a six-phase dual-winding motor having a first winding set 910 and a second winding set 940, each consisting of three phases. The first winding set 910 has U-phase, V-phase, and W-phase windings 91, 92, and 93 connected in a star configuration, and the second winding set 940 has X-phase, Y-phase, and Z-phase windings 94, 95, and 96 connected in a star configuration.

[0151] The first inverter 60 receives DC power from the first power supply 11 and has a plurality of first switching elements 61 to 66 corresponding to each phase of the first winding assembly 910, and is connected to the first winding assembly 910. The U-phase voltage VU, V-phase voltage VV, and W-phase voltage VW are applied to each phase winding 91, 92, and 93 of the first winding assembly 910 from the first inverter 60.

[0152] The second inverter 70 receives DC power from the second power supply 12 and has a plurality of second switching elements 71 to 76 corresponding to each phase of the second winding assembly 940, and is connected to the second winding assembly 940. The X-phase voltage VX, Y-phase voltage VY, and Z-phase voltage VZ are applied to each phase winding 94, 95, and 96 of the second winding assembly 940 from the second inverter 70.

[0153] Furthermore, the configuration of the control unit 300, temperature sensors 861-865, etc., in the fifth embodiment is the same as in the first embodiment. In the fifth embodiment, the drive mode switching control according to the first to third embodiments can be applied almost as is, and similar effects and advantages can be obtained.

[0154] (Sixth Embodiment) Next, the sixth embodiment will be described with reference to Figures 23 and 24. Figure 23 shows the overall configuration of a system to which the MG control device 106 of the sixth embodiment is applied. In this system, as with the fourth embodiment shown in Figure 19, two inverters 60 and 70 are connected to a single common power supply 13. The meanings of the first inverter input current Ib1, the second inverter input current Ib2, and the common power supply voltage VH are interpreted in accordance with the fourth embodiment. The MG 90 of the sixth embodiment is a six-phase dual-winding motor, as with the fifth embodiment.

[0155] The high-potential side wirings P1 and P2 of the first inverter 60 and the second inverter 70 are connected by a common high-potential side wiring Pcom, and the low-potential side wirings N1 and N2 are connected by a common low-potential side wiring Ncom. The relationship between the power Pb of the common power supply 13 and the power P_INV1 and P_INV2 shared by each inverter 60 and 70 is also expressed in accordance with the fourth embodiment as "Pb ≈ P_INV1 + P_INV2" and "Ib × VH ≈ Ib1 × VH + Ib2 × VH". Furthermore, the configuration of the control unit 300 is the same as in the fourth embodiment, in which at least one inverter control circuit has the function of adjusting the amount of power supplied from the common power supply 13 to the two inverters 60 and 70.

[0156] The time chart in Figure 24 shows the drive mode switching operation according to the sixth embodiment. Similar to Figures 10 and 21 of the first and fourth embodiments, the drive mode switches from the first inverter single-side drive mode to the double-side drive mode, and then back to the first inverter single-side drive mode. The changes in MG80 torque, rotational speed, and MG output are the same as in Figures 10 and 21, and the inverter input current, or the inverter power shared proportional to the input current, is the same as in Figure 21.

[0157] On the other hand, the amplitude of the voltage across the MG coil remains constant at the common power supply voltage VH, regardless of whether the mode is switched between single-sided and double-sided drive modes. Therefore, in the sixth embodiment, there is no sudden change in the voltage used to determine the inverter output, and thus there is no need to consider instantaneous correction or gradual change processing of the voltage command.

[0158] Thus, in the sixth embodiment, a system that drives a 6-phase dual-winding MG80 using a common power supply 13 with one winding and two inverters 60 and 70 switches between a single-sided drive mode and a double-sided drive mode. When the drive mode is switched, the power P_INV1 and P_INV2 shared by each inverter 60 and 70 are output arbitrated according to the drive mode after the switch.

[0159] This allows for stable shutdown of one inverter or a switch to dual-drive mode when it is possible to operate with lower losses by suspending the inverter based on the element loss characteristics and current distribution. Furthermore, when the thermal load on one inverter is high in single-drive mode or dual-drive mode, the thermal load can be distributed by stably suspending one inverter or a switch to dual-drive mode.

[0160] Furthermore, the switching and mediation unit 303 of the sixth embodiment provides the same effects as those described in (2) to (4) of the first embodiment. This point is as explained in the fourth embodiment. Also, the swapping of the roles of the power management circuits between the two inverter control circuits 301 and 302 is the same as in the above embodiments.

[0161] (Other embodiments) (a) In the above embodiment, the drive mode switching determination is basically performed based on the MG output request and the power supply status. In other embodiments, in addition to these factors, fail-safe transition requests based on the detection of failures of power supplies 11, 12 or inverters 60, 70, or signs of failure, may also be considered.

[0162] (b) In the system configurations using two independent power sources in the first and fifth embodiments, each power source is not limited to a secondary battery represented by a battery or capacitor. For example, one power source may be a secondary battery and the other power source may be a fuel cell or a generator.

[0163] (c) The number of phases of the open windings of the motor in the first and fourth embodiments is not limited to three phases, but may be four or more. Alternatively, a configuration in which two open windings are bridged together may be used.

[0164] (d) In the polyphase dual motor of the fifth and sixth embodiments, the number of phases in each winding set is not limited to three phases, but may be four or more. Also, the configuration of each winding set is not limited to a star connection, but may be a delta connection.

[0165] (e) The dual-power, dual-inverter motor drive system is applicable to pure electric vehicles such as electric vehicles and fuel cell vehicles, as well as electric-rich hybrid powertrains including PHVs (plug-in hybrids) and range extenders, and even to lightly electrified vehicles such as 12-48V ISGs (Integrated Starter Generators). This technology does not use any conventional reactor-based boost circuits, and instead uses a voltage-type circuit topology that enables high output with high efficiency by serializing the power supply voltages. This technology is suitable for applications where high output is required even in areas where conventional boost circuits and high-current inverters are thermally unsustainable in each vehicle, and enables more efficient operation than conventional powertrains.

[0166] The present invention is not limited in any way to the embodiments described above, and can be implemented in various forms without departing from its spirit. [Explanation of Symbols]

[0167] 101, 104...MG control device (motor drive device), 11...1st power supply (power supply), 12...2nd power supply (power supply), 13... Common power supply (power supply), 14... Switch, 300... Control Unit, 301...First inverter control circuit, 302...Second inverter control circuit, 303...Switching and mediation unit, 60...First inverter, 61-66...First switching element, 70...Second inverter, 71-76...Second switching element, 80...MG (motor motor), 81, 82, 83...Open winding (winding).

Claims

1. A motor drive device that controls the drive of an electric motor (80) having windings (81, 82, 83) to which each of two inverters connected to a power source (11, 12, 13) is connected, DC power is input from the aforementioned power supply, and a first inverter (60), which is one of the two inverters, has a plurality of first switching elements (61-66) provided corresponding to each phase of the winding, and is connected to one end of the winding. DC power is input from the aforementioned power supply, and a second inverter (70), which is the other of the two inverters, has a plurality of second switching elements (71-76) provided corresponding to each phase of the winding, and is connected to the other end of the winding. A control unit (300) having two inverter control circuits: a first inverter control circuit (301) that generates a first voltage command, which is an output voltage command to the first inverter, based on a torque command, and a second inverter control circuit (302) that generates a second voltage command, which is an output voltage command to the second inverter; and a switching arbitration unit (303) that determines whether to switch between a one-sided drive mode in which one of the two inverters is switched and a two-sided drive mode in which both of the two inverters are switched, and arbitrates the output of each inverter at the time of switching so that the output of the motor is continuous before and after the switching of the drive mode; Equipped with, At least one of the inverter control circuits has a function to adjust the amount of power supplied from the power source to the two inverters. The aforementioned switching mediation unit is: Based on the self-inverter voltage utilization rate calculated by dividing the inverter line voltage by the inverter input voltage for at least one of the inverters, a switching determination is made between the single-sided drive mode and the double-sided drive mode, such that when the self-inverter voltage utilization rate increases in the single-sided drive mode and reaches the double-sided switching threshold, the system switches to the double-sided drive mode, and when the self-inverter voltage utilization rate decreases in the double-sided drive mode and reaches the single-sided switching threshold, the system switches back to the single-sided drive mode. When switching from the single-sided drive mode to the double-sided drive mode, the power of the drive-start side inverter, which starts switching drive from a dormant state, is gradually increased from zero. An electric motor drive device that, when switching from the aforementioned bilateral drive mode to the aforementioned unilateral drive mode, gradually reduces the power of the drive termination side inverter, which terminates the switching drive and enters a pause state, down to zero.

2. A motor drive device that controls the drive of an electric motor (80) having connected windings (81, 82, 83) to each of two inverters connected to a common power supply (13), A first inverter (60), which is one of the two inverters, has a plurality of first switching elements (61 to 66) provided corresponding to each phase of the winding, and is connected to one end of the winding. A second inverter (70), which is the other of the two inverters, has a plurality of second switching elements (71-76) provided corresponding to each phase of the winding, and is connected to the other end of the winding. A common high-potential wiring (Pcom) connects the high-potential wiring (P1, P2) of the first inverter and the second inverter, A common low-potential wiring (Ncom) connects the low-potential wiring (N1, N2) of the first inverter and the second inverter, A switch (14) is provided in at least one of the common high-potential wiring or the common low-potential wiring, and is capable of interrupting the current path. A control unit (300) having two inverter control circuits: a first inverter control circuit (301) that generates a first voltage command, which is an output voltage command to the first inverter, based on a torque command, and a second inverter control circuit (302) that generates a second voltage command, which is an output voltage command to the second inverter; and a switching arbitration unit (303) that determines whether to switch between a one-sided drive mode in which one of the two inverters is switched and a two-sided drive mode in which both of the two inverters are switched, and arbitrates the output of each inverter at the time of switching so that the output of the motor is continuous before and after the switching of the drive mode; Equipped with, In a star connection circuit configured by neutralizing one of the inverters with the switch open, the other inverter is capable of operating in the single-sided drive mode. With the switch closed, the H-bridge circuit, which is composed of the first switching element and the second switching element for each corresponding phase, is capable of operating in the double-sided drive mode. At least one of the inverter control circuits has a function to adjust the amount of power supplied from the common power supply to the two inverters. The aforementioned switching mediation unit is: Based on the self-inverter voltage utilization rate calculated by dividing the inverter line voltage by the inverter input voltage for at least one of the inverters, a switching determination is made between the single-sided drive mode and the double-sided drive mode, such that when the self-inverter voltage utilization rate increases in the single-sided drive mode and reaches the double-sided switching threshold, the system switches to the double-sided drive mode, and when the self-inverter voltage utilization rate decreases in the double-sided drive mode and reaches the single-sided switching threshold, the system switches back to the single-sided drive mode. When switching from the single-sided drive mode to the double-sided drive mode, the power of the drive-start side inverter, which starts switching drive from a dormant state, is gradually increased from zero. An electric motor drive device that, when switching from the aforementioned bilateral drive mode to the aforementioned unilateral drive mode, gradually reduces the power of the drive termination side inverter, which terminates the switching drive and enters a pause state, down to zero.

3. In the control configuration in which the output of the inverter is determined based on the voltage of the common power supply in the one-sided drive mode, and the output of each inverter is determined based on twice the voltage of the common power supply in the two-sided drive mode, The motor drive device according to claim 2, wherein the switching arbitration unit corrects the voltage command to the inverter operating in the one-sided drive mode when the drive mode is switched, and carries it over to the next processing cycle.

4. The aforementioned switching mediation unit is: When the first inverter switches from the single-sided drive mode to the double-sided drive mode, it corrects the value of the voltage command by twice the voltage of the common power supply. The motor drive device according to claim 3, wherein when switching from the double-sided drive mode to the single-sided drive mode, the value of the voltage command is corrected by half the value of the voltage of the common power supply.

5. In the control configuration in which the output of the inverter is determined based on the voltage of the common power supply in the one-sided drive mode, and the output of each inverter is determined based on twice the voltage of the common power supply in the two-sided drive mode, The motor drive device according to claim 3, wherein when the first inverter switches from the one-sided drive mode to the two-sided drive mode, the switching arbitration unit performs a gradual change process that continuously changes the voltage value with respect to time from the voltage of the common power supply to twice the voltage of the common power supply.

6. A motor drive device for controlling the drive of a motor (80) having windings (81, 82, 83) to which each of two inverters, each individually connected to a plurality of power sources (11, 12), is connected, DC power is input from a predetermined number of first power supplies (11) connected from the plurality of power supplies, and a first inverter (60), which is one of the two inverters, has a plurality of first switching elements (61 to 66) provided corresponding to each phase of the winding, and is connected to one end of the winding. DC power is input from a second power supply (12) among the plurality of power supplies that is not connected to the first inverter, and a second inverter (70), which is the other of the two inverters, has a plurality of second switching elements (71 to 76) provided corresponding to each phase of the winding, and is connected to the other end of the winding, A control unit (300) having two inverter control circuits: a first inverter control circuit (301) that generates a first voltage command, which is an output voltage command to the first inverter, based on a torque command, and a second inverter control circuit (302) that generates a second voltage command, which is an output voltage command to the second inverter; and a switching arbitration unit (303) that determines whether to switch between a one-sided drive mode in which one of the two inverters is switched and a two-sided drive mode in which both of the two inverters are switched, and arbitrates the output of each inverter at the time of switching so that the output of the motor is continuous before and after the switching of the drive mode; Equipped with, At least one of the inverter control circuits has a function to adjust the amount of power supplied from the plurality of power sources to the two inverters, The aforementioned switching mediation unit is: Based on the self-inverter voltage utilization rate calculated by dividing the inverter line voltage by the inverter input voltage for at least one of the inverters, a switching determination is made between the single-sided drive mode and the double-sided drive mode, such that when the self-inverter voltage utilization rate increases in the single-sided drive mode and reaches the double-sided switching threshold, the system switches to the double-sided drive mode, and when the self-inverter voltage utilization rate decreases in the double-sided drive mode and reaches the single-sided switching threshold, the system switches back to the single-sided drive mode. When switching from the single-sided drive mode to the double-sided drive mode, the power of the drive-start side inverter, which starts switching drive from a dormant state, is gradually increased from zero. An electric motor drive device that, when switching from the aforementioned bilateral drive mode to the aforementioned unilateral drive mode, gradually reduces the power of the drive termination side inverter, which terminates the switching drive and enters a pause state, down to zero.

7. In the control configuration in which the output of the inverter is determined based on the voltage of the first power supply in the one-sided drive mode, and the output of each inverter is determined based on the voltage sum of the multiple power supplies in the two-sided drive mode, The motor drive device according to claim 6, wherein the switching arbitration unit corrects the voltage command to the inverter operating in the one-sided drive mode when the drive mode is switched, and carries it over to the next processing cycle.

8. Let VH1 be the voltage of the first power supply, VH2 be the voltage of the second power supply, and let Vdq be the value of the voltage command. The aforementioned switching mediation unit is: When the first inverter switches from the one-sided drive mode to the two-sided drive mode, the value of the voltage command is corrected by equation (1.1), The motor drive device according to claim 7, wherein the value of the voltage command is corrected by formula (1.2) when switching from the double-sided drive mode to the single-sided drive mode. [Math 1]

9. In the control configuration in which the output of the inverter is determined based on the voltage of the first power supply in the one-sided drive mode, and the output of each inverter is determined based on the voltage sum of the multiple power supplies in the two-sided drive mode, The motor drive device according to claim 7, wherein when the first inverter switches from the one-sided drive mode to the two-sided drive mode, the switching arbitration unit performs a gradual change process that continuously changes the voltage value with respect to time from the voltage of the first power supply to the sum of the voltages of the multiple power supplies.

10. A motor drive device that controls the drive of a motor (80) having motors (81, 82, 83) each having windings (81, 82, 83) connected to two inverters connected to a common power supply (13), A first inverter (60), which is one of the two inverters, has a plurality of first switching elements (61 to 66) provided corresponding to each phase of the winding, and is connected to one end of the winding. A second inverter (70), which is the other of the two inverters, has a plurality of second switching elements (71-76) provided corresponding to each phase of the winding, and is connected to the other end of the winding. A common high-potential wiring (Pcom) connects the high-potential wiring (P1, P2) of the first inverter and the second inverter, A common low-potential wiring (Ncom) connects the low-potential wiring (N1, N2) of the first inverter and the second inverter, A switch (14) is provided in at least one of the common high-potential wiring or the common low-potential wiring, and is capable of interrupting the current path. A control unit (300) having two inverter control circuits: a first inverter control circuit (301) that generates a first voltage command, which is an output voltage command to the first inverter, based on a torque command, and a second inverter control circuit (302) that generates a second voltage command, which is an output voltage command to the second inverter; and a switching arbitration unit (303) that determines whether to switch between a one-sided drive mode in which one of the two inverters is switched and a two-sided drive mode in which both of the two inverters are switched, and arbitrates the output of each inverter at the time of switching so that the output of the motor is continuous before and after the switching of the drive mode; Equipped with, In a star connection circuit configured by neutralizing one of the inverters with the switch open, the other inverter is capable of operating in the single-sided drive mode. With the switch closed, the H-bridge circuit, which is composed of the first switching element and the second switching element for each corresponding phase, is capable of operating in the double-sided drive mode. At least one of the inverter control circuits has a function to adjust the amount of power supplied from the common power supply to the two inverters. In the control configuration in which the output of the inverter is determined based on the voltage of the common power supply in the one-sided drive mode, and the output of each inverter is determined based on twice the voltage of the common power supply in the two-sided drive mode, The aforementioned switching arbitration unit corrects the voltage command to the inverter operating in the single-sided drive mode when the drive mode is switched, and carries it over to the next processing cycle.

11. The aforementioned switching mediation unit is: When the first inverter switches from the single-sided drive mode to the double-sided drive mode, it corrects the value of the voltage command by twice the voltage of the common power supply. The motor drive device according to claim 10, wherein when switching from the two-sided drive mode to the one-sided drive mode, the value of the voltage command is corrected by half the value of the voltage of the common power supply.

12. In the control configuration in which the output of the inverter is determined based on the voltage of the common power supply in the one-sided drive mode, and the output of each inverter is determined based on twice the voltage of the common power supply in the two-sided drive mode, The motor drive device according to claim 10, wherein when the first inverter switches from the one-sided drive mode to the two-sided drive mode, the switching arbitration unit performs a gradual change process that continuously changes the voltage value with respect to time from the voltage of the common power supply to twice the voltage of the common power supply.

13. A motor drive device for controlling the drive of a motor (80) having windings (81, 82, 83) to which each of two inverters, each individually connected to a plurality of power sources (11, 12), is connected, DC power is input from a predetermined number of first power supplies (11) connected from the plurality of power supplies, and a first inverter (60), which is one of the two inverters, has a plurality of first switching elements (61 to 66) provided corresponding to each phase of the winding, and is connected to one end of the winding. DC power is input from a second power supply (12) among the plurality of power supplies that is not connected to the first inverter, and a second inverter (70), which is the other of the two inverters, has a plurality of second switching elements (71 to 76) provided corresponding to each phase of the winding, and is connected to the other end of the winding, A control unit (300) having two inverter control circuits: a first inverter control circuit (301) that generates a first voltage command, which is an output voltage command to the first inverter, based on a torque command, and a second inverter control circuit (302) that generates a second voltage command, which is an output voltage command to the second inverter; and a switching arbitration unit (303) that determines whether to switch between a one-sided drive mode in which one of the two inverters is switched and a two-sided drive mode in which both of the two inverters are switched, and arbitrates the output of each inverter at the time of switching so that the output of the motor is continuous before and after the switching of the drive mode; Equipped with, At least one of the inverter control circuits has a function to adjust the amount of power supplied from the plurality of power sources to the two inverters, In the control configuration in which the output of the inverter is determined based on the voltage of the first power supply in the one-sided drive mode, and the output of each inverter is determined based on the voltage sum of the multiple power supplies in the two-sided drive mode, The aforementioned switching arbitration unit corrects the voltage command to the inverter operating in the single-sided drive mode when the drive mode is switched, and carries it over to the next processing cycle.

14. Let VH1 be the voltage of the first power supply, VH2 be the voltage of the second power supply, and let Vdq be the value of the voltage command. The aforementioned switching mediation unit is: When the first inverter switches from the one-sided drive mode to the two-sided drive mode, the value of the voltage command is corrected by equation (1.1), The motor drive device according to claim 13, wherein the value of the voltage command is corrected by formula (1.2) when switching from the double-sided drive mode to the single-sided drive mode. [Math 2]

15. In the control configuration in which the output of the inverter is determined based on the voltage of the first power supply in the one-sided drive mode, and the output of each inverter is determined based on the voltage sum of the multiple power supplies in the two-sided drive mode, The motor drive device according to claim 13, wherein when the first inverter switches from the one-sided drive mode to the two-sided drive mode, the switching arbitration unit performs a gradual change process that continuously changes the voltage value with respect to time from the voltage of the first power supply to the sum of the voltages of the multiple power supplies.

Images