Electric motor driving device

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 has been 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 capacitance type power source), and drives the motor with the more suitable power source according to the operating temperature range. Further, this system switches between single-side power source drive and both-side power source drive in consideration of the states and characteristics of each power source in order to compensate for an instantaneous output decrease of the motor.

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] Two inverters each independently output voltage pulses, and the voltage applied to the motor coils is determined thereby. In other words, if the output of each inverter cannot be controlled to be the optimum value required for the motor at that time, torque fluctuations will be caused by current disturbances generated by voltage shortages or surpluses. Furthermore, in the worst case, there is a risk of component failure due to overcurrent generated by excessive voltage application. This problem applies not only to a two-power-supply two-inverter system but also to a system in which two inverters are connected to one common power supply.

[0006] The present invention was created in view of the above problems, and an object thereof is to provide a motor drive device that stabilizes the motor output and maintains continuity when switching between a single-sided drive mode and a double-sided drive mode in a two-inverter configuration.

Means for Solving the Problems

[0007] A motor drive device according to a first aspect (comprehensive 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 includes a first inverter (60), a second inverter (70), and a control unit (300).

[0008] The first inverter, which is one of the two inverters, receives DC power from the power supply and 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. The second inverter, which is the other of the two inverters, receives DC power from the power supply and 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.

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

[0010] The switching arbitration unit determines the switching between a "single-sided drive mode" in which either one of the two inverters is driven by switching and a "both-sided drive mode" in which both of the two inverters are driven by switching, and arbitrates the outputs of the inverters at the time of switching so as to make the output of the motor continuous before and after the switching of the drive mode.

[0011] The switching arbitration unit performs the switching determination between the single-sided drive mode and the both-sided drive mode such that, 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, when the self-inverter voltage utilization rate increases in the single-sided drive mode and reaches the both-sided switching threshold, it switches to the both-sided drive mode, and when the self-inverter voltage utilization rate decreases in the both-sided drive mode and reaches the single-sided switching threshold, it switches to the single-sided drive mode. When switching from the single-sided drive mode to the both-sided drive mode, the switching arbitration unit gradually changes and increases the amount of power of the drive start side inverter from zero. Also, when switching from the both-sided drive mode to the single-sided drive mode, the switching arbitration unit gradually changes and decreases the amount of power of the drive end side inverter to zero.

[0012] Here, the "drive start side inverter" is an inverter that starts switching drive from a standby state. The "drive end side inverter" is an inverter that ends switching drive and shifts to a standby state. Also, "zero" of the amount of power is not limited to exact 0 [W], but includes minute values within a range determined to be near zero based on the common technical knowledge in the technical field. "Gradual change" means a speed change at a level that can be followed by feedback control.

[0013] The switching arbitration unit of the present invention makes the electric power amount of each inverter change gradually when switching the drive mode, so as to make the output of the motor before and after switching continuous. Thereby, it is possible to avoid damage to equipment caused by torque fluctuations of the motor and overcurrents generated during the fluctuations. In addition, it is possible to eliminate fluctuations in the torque of the motor due to the influence of power fluctuations caused by the operation during drive mode switching.

[0014] The motor drive device according to the second aspect of the present invention is a motor drive device that controls the drive of a motor (80) having windings (81, 82, 83) to which each of two inverters connected to a common power supply (13) is connected. This motor drive device includes 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] The first inverter, 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. The second inverter, 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. The common high-potential side wiring connects the high-potential side wirings (P1, P2) of the first inverter and the second inverter to each other. The common low-potential side wiring connects the low-potential side wirings (N1, N2) of the first inverter and the second inverter to each other. The switch is provided on at least one of the common high-potential side wiring and the common low-potential side wiring and can cut off the current path. The control unit has two inverter control circuits, namely, a first inverter control circuit (301) and a two-inverter control circuit (302) similar to the first aspect, and a switching arbitration unit (303). At least one of the inverter control circuits has a function of adjusting the electric power amount supplied from the common power supply to the two inverters.

[0016] In the motor drive device according to the second aspect, in a star connection circuit configured by connecting one inverter to a neutral point with the switch open, the other inverter can operate in a single-sided drive mode. Also, in an H-bridge circuit configured by the first switching element and the second switching element of each corresponding phase with the switch closed, it can operate in a bilateral drive mode.

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

[0018] The first inverter, 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, with DC power input from a first power source (11) to which a predetermined number of the plurality of power sources are connected. The second inverter, 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. The control unit has two inverter control circuits, namely a first inverter control circuit (301) and a two-inverter control circuit (302) similar to the first aspect, and a switching arbitration unit (303). At least one of the inverter control circuits has a function of adjusting the amount of power supplied from the plurality of power sources to the two inverters.

[0019] In the second and third aspects, the switching arbitration unit makes a switching determination in the same manner as in the first aspect, and changes the amount of power of the driving start side inverter and the amount of power of the driving 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 the single-sided drive mode, the output of the inverter is determined based on the voltage of one of the first power supplies, and in the bilateral drive mode, in the 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-sided drive mode at the time of switching the drive mode and passes it on to the next processing cycle.

Brief Description of Drawings

[0021]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

Figure 14

Figure 15

Figure 16

Figure 17

Figure 18

Figure 19

Figure 20

Figure 21

Figure 22

Figure 23

Figure 24

Embodiments for Carrying Out the Invention

[0022] Hereinafter, a plurality of embodiments of the motor drive device will be described with reference to the drawings. The "present embodiment" includes the first to sixth embodiments. The motor drive device of the present embodiment is a device that controls the drive of a motor generator (hereinafter, "MG"), which is a power source of a hybrid vehicle or an electric vehicle, by two inverters in a system where a three-phase AC motor, the MG, is driven. The "MG" and the "MG control device" in the embodiment correspond to the "motor" and the "motor drive device", respectively.

[0023] The first, fourth, fifth, and sixth embodiments are combinations of the number of power sources of the system to which the MG control device is applied and the difference in the winding configuration of the MG. Regarding the number of power sources, two power sources or one common power source is used. Regarding the winding configuration of the MG, an open winding in which the ends are not connected, that is, an open winding, or two sets of windings connected in star or delta are used. The first embodiment is applied to a system of "two power sources + open winding", and the fourth embodiment is applied to a system of "one power source + open winding". The fifth embodiment is applied to a system of "two power sources + two sets of windings", and the sixth embodiment is applied to a system of "one power source + two sets of windings".

[0024] The second and third embodiments differ in the switching control of the drive mode in the system configuration of the first embodiment. The switching control of the second and third embodiments can also be used in the system configurations of the fourth to sixth embodiments. Hereinafter, mainly the first to third embodiments will be described in detail. Regarding the fourth to sixth embodiments, the technical idea of the first to third embodiments is applied as it is or with some modifications.

[0025] [System Configuration of the First Embodiment] FIG. 1 shows the overall configuration of a system according to a first embodiment in which a "two-power-supply two-inverter", that is, two power supplies 11 and 12 and two inverters 60 and 70 are used. The system configuration of FIG. 1 is also applicable to the second and third embodiments. 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, MG80 has a function as an electric motor that generates torque for driving drive wheels, and a function as a generator that can be driven by the kinetic energy of the vehicle transmitted from an engine or drive wheels to generate electricity.

[0026] In MG80 according to the first embodiment, the three-phase windings 81, 82, and 83 are configured as an open winding in which the ends are not connected to each other. Each phase output terminal of the first inverter 60 is connected to one ends 811, 821, and 831 of the three-phase open winding 81, 82, and 83, and each phase output terminal of the second inverter 70 is connected to the other ends 812, 822, and 832 of the three-phase open winding 81, 82, and 83. The rotation angle sensor 85 is constituted by a resolver or the like and detects the mechanical angle θm of MG80. The mechanical angle θm is converted into 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 insulated from each other, and each is a rechargeable power storage device such as a nickel-hydrogen or lithium-ion secondary battery or an electric double layer capacitor. For example, an output-type lithium-ion battery may be used for the first power supply 11 and a capacity-type lithium-ion battery may be used for the second power supply 12. The power of the power supplies 11 and 12 is represented by SOC (State Of Charge).

[0028] Two inverters 60 and 70 are individually supplied with DC power 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 source 11 via the first inverter 60 and with power from the second power source 12 via the second inverter 70. The 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. The 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 for detecting the phase current flowing through the three-phase open windings 81, 82, and 83 is provided in the power path from the first inverter 60 to the MG80. In the example of FIG. 1, the V-phase current Iv and the W-phase current Iw are detected, but any two-phase or three-phase currents may be detected. Also, the current sensor 84 may be provided in the power path from the second inverter 70 to the MG80, or may be provided in both paths of the first inverter 60 and the second inverter 70.

[0031] The first capacitor 16 is connected between the high-potential side wiring P1 and the low-potential side wiring N1, and the second capacitor 17 is connected between the high-potential side wiring P2 and the low-potential side 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 shared power P_INV1 of the first inverter 60 is represented by "P_INV1 = Ib1 × VH1", and the shared power P_INV2 of the second inverter 70 is represented by "P_INV2 = Ib2 × VH2". The sum of the powers of the two inverters 60 and 70, "P_INV1 + P_INV2", is supplied to MG80.

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

[0033] Each of the switching elements 61 to 66 and 71 to 76 is composed of, for example, an IGBT, and a freewheeling diode that allows current to flow from the low-potential side to the high-potential side is connected in parallel. In order to prevent a short circuit between the high-potential side wirings P1 and P2 and the low-potential side wirings N1 and N2, the upper arm element and the lower arm element of each phase are not turned on simultaneously and are controlled to be complementary on and off, that is, when one is on, the other is off.

[0034] The control unit 300 is composed of a microcomputer or the like, and includes a CPU, a ROM, an I / O, and bus lines connecting these components (not shown). The control unit 300 executes control by software processing in which a program stored in advance in a physical memory device such as a ROM (that is, a readable non-transitory tangible recording medium) is executed by the CPU, or by hardware processing using a dedicated electronic circuit.

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

[0036] The temperature sensors 861, 862, 863, 864, 865 detect the temperatures Hb1 of the first power supply 11, Hb2 of the second power supply 12, Hinv1 of the first inverter 60, Hinv2 of the second inverter 70, and Hmg of the MG80, respectively, and notify the control unit 300. The temperature of each part is one of the factors for determination in the drive mode switching determination described later.

[0037] [Overview of One-Side Drive Mode and Both-Side Drive Mode] A control mode in which either one of the two inverters 60 and 70 is switched and driven is called a "single-sided drive mode", and a control mode in which both of the two inverters 60 and 70 are switched and driven is called a "double-sided drive mode". This embodiment focuses on the switching operation between the single-sided drive mode and the double-sided drive mode. Hereinafter, 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 by the first inverter 60 to the double-sided drive mode will be mainly described. The case of switching from the single-sided drive mode by the second inverter 70 to the double-sided drive mode is the same and will not be described, but it is not limited as a functional means.

[0038] FIG. 2(a) shows the switching drive in the single-sided drive mode, and FIG. 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 and driven. Also, for the second inverter 70, one of the upper arm switching elements 71, 72, 73 of all phases or one of the lower arm switching elements 74, 75, 76 of all phases is turned on and the other is turned off, and they are electrically connected to the neutral point. In the double-sided drive mode, by switching and driving both inverters 60 and 70, the voltages of the two power supplies 11 and 12 are connected in series.

[0039] Regarding the concept of drive mode switching, refer to the N-T characteristic diagrams in FIGS. 3(a) and 3(b). The hatched area in each figure is the area where the drive mode is preferably applied. The single-sided drive mode shown in FIG. 3(a) has the advantage of high efficiency at low loads and the disadvantage of a low upper limit of performance at high loads, so it is advantageous at low loads. The double-sided drive mode shown in FIG. 3(b) has the advantage of a high upper limit of performance at high loads and the disadvantage of low efficiency at low loads, so it is advantageous at high loads.

[0040] Therefore, it is possible to realize a drive that achieves both output and efficiency by switching to the single-sided drive mode so as to achieve low-loss drive at low loads while ensuring sufficient output by the double-sided drive mode at high loads. In this specification, the verb "switch" is written with a reading kana, and the noun "switching" is written without a reading kana.

[0041] [Problems and Key Points] As an inevitable problem of the two - power - two - inverter system, a sudden change in the voltage across the MG coil always occurs when switching the drive mode. That is, the two inverters 60 and 70 each independently output voltage pulses, and the voltage applied to the MG coil is determined by them. In other words, if the outputs of the respective inverters 60 and 70 cannot be controlled to be the optimum values required for the MG 80 at that time, torque fluctuations will be caused by current disturbances due to voltage over - or under - deficiencies. Furthermore, in the worst - case scenario, there is a risk of component failure due to over - current generated by excessive voltage application.

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

[0043] [1] Gradually change so that the output change of the inverter does not become steep during the rise and fall when switching the drive mode. [2] Eliminate the output fluctuation by instantaneously correcting the voltage command aimed at eliminating the output change factor of the self - inverter within the self - inverter. [3] Regardless of the state change before and after switching, perform a stable switch at the timing of the target MG output by an appropriate and uniquely determined switching determination, and achieve both high - output drive and low - loss drive at low output.

[0044] [Configuration of the Control Unit] Fig. 4 shows the schematic configuration of the control unit 300. In the following figures, the 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 the dq-axis coordinates). The inverter control circuits 301 and 302 may be provided in individual microcontrollers respectively, or may be provided in a common single microcontroller. Each of the inverter control circuits 301 and 302 generates independent and coordinated voltage commands for driving as a two-power-supply two-inverter system.

[0045] As information acquired by the control unit 300, since MG80 is common, the detected values of the angle (specifically, the electrical angle θe) and the three-phase current may be common. However, as shown by the dashed line, a plurality of current sensors 84 and rotation angle sensors 85 may be provided, and each of the inverter control circuits 301 and 302 may acquire the corresponding detected values. Also, when the second inverter control circuit 302 performs feedforward control, it may not 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 of the inverter control circuits adjusts the amount of power supplied from the two power supplies 11 and 12 to the two inverters 60 and 70. In the configuration of Fig. 4, one of the first inverter control circuits 301 functions as a torque management circuit and realizes torque by feedback control. Also, the other second inverter control circuit 302 functions as a power management circuit and manages power by feedforward control and power distribution control.

[0047] The power management circuit has a function of adjusting the amount of power supplied from the two power supplies 11 and 12 to the two inverters 60 and 70. Further, in power distribution control, the distribution of the power supplied from the two power supplies 11 and 12 to the two inverters 60 and 70 is managed. In the following figures, "feedback" is denoted as "FB" and "feedforward" is denoted as "FF". Note that the roles of the first inverter control circuit 301 and the second inverter control circuit 302 may be interchanged.

[0048] In this configuration, while disturbance suppression is corrected so that torque follows the command by feedback control of the first inverter control circuit 301, in the second inverter control circuit 302, the power of each inverter 60, 70 is managed by feedback control uniquely determined by the command. In this way, while the power management circuit adjusts the inverter power, the control unit 300 corrects the disturbance suppression by feedback control so that the torque management circuit realizes the required torque, and thus can achieve both the realization of the desired MG torque and each power supply power without control interference.

[0049] By the way, since the dq control for the inverter control circuits 301, 302 to drive the inverters 60, 70 is independent, while there is a degree of control freedom, if the voltage across the MG coil generated by the cooperation of each inverter command is not optimal for MG80, the MG torque (output) and each inverter power will easily fluctuate. This fluctuation becomes more prominent in the scene of switching between the single-sided drive mode and the double-sided drive mode where the voltage across the MG coil changes most significantly in a short time.

[0050] Therefore, the control unit 300 of the present embodiment determines the switching between the single-sided drive mode and the double-sided drive mode after setting the inverter control circuits 301, 302 to play the roles of torque management and power management, and has a switching arbitration unit 303 that arbitrates the outputs of the inverters 60, 70 at the time of switching. The switching arbitration unit 303 arbitrates the power change amount so as not to be affected by the change in the voltage across the MG coil at the time of switching between the single-sided drive mode and the double-sided drive mode, and makes the MG output continuous before and after the switching.

[0051] In the configuration of FIG. 4, the torque command trq * and the power distribution request from an external upper control circuit are once input to the switching arbitration unit 303 and then notified to the inverter control circuits 301, 302. However, it is not limited to this configuration, and the torque command trq * and the power distribution request may be notified to the switching arbitration unit 303 after being input to the inverter control circuits 301, 302.

[0052] When switching from the single-sided drive mode to the double-sided drive mode, the switching arbitration unit 303 gradually increases the amount of power of the inverter on the drive start side from zero. Also, when switching from the double-sided drive mode to the single-sided drive mode, the switching arbitration unit 303 gradually decreases the amount of power of the inverter on the drive end side until it reaches zero. The "zero" of the amount of power does not refer only to the exact 0 [W], but includes minute values within the range determined to be "near zero" based on the common technical knowledge in the technical field. Thereby, regardless of the change in the voltage across the MG coil, the continuity of the MG output can be maintained and control fluctuations can be eliminated.

[0053] Here, the "inverter on the drive start side" is the inverter that starts switching drive from the previous rest state. The "inverter on the drive end side" is the inverter that ends the switching drive that has been performed until now and transitions to the rest state. When switching from the single-sided drive mode of the first inverter to the double-sided drive mode, the second inverter 70 corresponds to the "inverter on the drive start side". Also, when switching from the double-sided drive mode to the single-sided drive mode of the first inverter, the second inverter 70 corresponds to the "inverter on the drive end side".

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

[0055] (First Embodiment) Referring to FIGS. 5 to 12, as a first embodiment, a control configuration related to the switching between the first inverter single-sided drive mode and the double-sided drive mode will be described. As shown in FIG. 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 the switching between the single-sided drive mode and the double-sided drive mode. This is an inevitable problem of the two-power two-inverter system. And if it is impossible to cope with the change in the voltage across the MG coil directly related to the generation of the three-phase current, there will be an excess or deficiency in the voltage across the MG coil required to flow the desired current, and current fluctuations will be easily caused from the relationship between the electrical circuit and the pulse voltage output.

[0056] FIG. 5(b) shows a schematic control configuration when switching between the first inverter single-sided drive mode and the double-sided drive mode. Since the basic control configurations such as the calculation of the current command Idq, the calculation of the voltage command Vdq, and the PWM control in FIG. 5(b) are well-known techniques, the description thereof will be omitted. Hereinafter, the d-axis current command Id and the q-axis current command Iq are collectively referred to as the current command Idq, and the d-axis voltage command Vd and the q-axis voltage command Vq are collectively referred to as the voltage command Vdq. Here, the d-axis voltage command Vd is 0 or a negative value. Hereinafter, "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 driven by switching alone, the first power supply voltage VH1 is applied as the input voltage of the PWM control. On the other hand, when both inverters 60 and 70 are driven by switching while the first inverter 60 continues the switching drive and the second inverter 70 starts the switching drive, the sum of the voltages of the two power supplies (VH1 + VH2) is applied as the input voltage of the PWM control. Thus, a switching occurs in the control from the MG perspective. And when the drive mode is switched, if the switching of each inverter 60, 70 cannot be coordinated and there is an excess or deficiency in the applied voltage with respect to the required voltage, current fluctuations will occur.

[0058] In the first embodiment, in order to avoid the occurrence of over- or under-application of voltage and maintain the continuity of MG output, the following switching process is executed. Next, with reference to the flowchart of FIG. 6 and the control block diagram of FIG. 7, the drive mode switching process according to the first embodiment will be described. In the following description of the flowchart, the symbol "S" means step. Also, in FIG. 7, it is assumed that the first inverter control circuit 301 is a torque management circuit and the second inverter control circuit 302 is a power management circuit.

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

[0060] In S22, the voltage command Vdq is instantaneously corrected when the drive mode is switched. When switching from the single-side drive mode of the first inverter to the double-side drive mode, the voltage command Vdq1 is instantaneously corrected by Equation (1.1). When switching from the double-side drive mode to the single-side drive mode of the first inverter, the voltage command Vdq1 is instantaneously corrected by Equation (1.2).

[0061]

Equation

[0062] Supplement the technical significance of instantaneous correction. As is well known, feedback control is a tracking control for a first-order lag system. Also, since MG80 has a coil, it becomes a first-order lag system as an electric circuit. Therefore, it is obvious that the response of the MG control that controls the first-order lag MG80 with the control of the first-order lag system becomes a first-order lag. Therefore, for a steep change in the voltage across the MG coil such as in the two-power two-inverter configuration, that is, a step change depending on the instantaneous superposition of the output pulse voltages of the two inverters 60 and 70, it can only respond with a first-order lag. Therefore, in the first embodiment, this problem is solved by instantaneously correcting the voltage command Vdq. Also, in the following second embodiment, this problem is solved by performing slow change processing.

[0063] In S23, in order for the inverter output, and thus the MG output, to continue to maintain continuity, the voltage command Vdq1 is set as the carry-over amount to the next control process. In the first inverter control circuit 301 which is a torque management circuit, the integral term of the feedback control is reset. Also, in the second inverter control circuit 302 which is a power management circuit, the voltage command Vdq2 is set for power calculation in feedforward control. In S24, in the second inverter control circuit 302 on the power management side, the amount of power output is gradually changed so as not to cause disturbance to the first inverter control circuit 301 on the torque management side.

[0064] Regarding the above switching process, supplement with reference to the block diagram of FIG. 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 at the time of switching. In the integral term reset block, the carry-over amount for the next feedback control is matched only at the time of switching. As a result, the duty ratio INV1_duty commanded to the first inverter 60 is output while maintaining continuity with that before switching even after switching.

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

[0066] Next, referring to the sub - flowchart of FIG. 8, details of the switching determination from the single - side drive mode to the both - side drive mode in S10 of FIG. 6 will be supplemented. In S11, the MG control device 101 is driving in the first inverter single - side drive mode. In S12, it is determined whether the temperature Hb1 of the first power source 11 is higher than the upper limit of the appropriate range. In S13, it is determined whether the SOC of the first power source 11 is lower than the lower limit of the appropriate range. If it is determined YES in S12 or S13, regardless of the presence of a high - output request, it is preferable to reduce the load on the first power source 11. Therefore, the process proceeds to S16, and the switching arbitration unit 303 determines to perform the switching from the first inverter single - side drive mode to the both - side drive mode.

[0067] In the both - side drive mode of S16, a pattern in which each of the inverters 60 and 70 is driven in the PWM control mode is selected, and it is preferable to perform active power adjustment so that the temperature and SOC of the first power source 11 fall within the appropriate range. Note that the output may be limited depending on the temperature of the first power source 11.

[0068] If it is determined NO in S12 and S13, in S14, it is determined whether there is a high - output request for MG80. If it is determined YES in S14, then in S15, it is determined whether there is a requirement for high - efficiency operation. If it is determined YES in S15, the process proceeds to S17, and the switching arbitration unit 303 determines to perform the switching from the first inverter single - side drive mode to the both - side drive mode. In the both - side drive mode of S17, a pattern in which the inverter on the side with a larger amount of power is driven in the rectangular - wave control mode and the other inverter is driven in the PWM control mode is selected, thereby performing high - efficiency operation.

[0069] When it is determined as YES in S14 and NO in S15, the process proceeds to S16, and in the bilateral drive mode, each of the inverters 60 and 70 is driven in the PWM control mode. In this case, normal operation that is not intentional efficient operation is performed according to the torque command and the power command. Also, when it is determined as NO in S14, the output in the current unilateral 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 the switching determination to the bilateral drive mode.

[0070] Regarding the control mode selected in the bilateral drive mode, in the PWM control mode, a plurality of pulses corresponding to the carrier frequency are output in one electrical cycle based on the comparison between the voltage command and the carrier wave, and in the rectangular wave control mode, one pulse is output in one electrical cycle. Also, the PWM control mode includes a sine wave control mode and an overmodulation control mode according to the voltage utilization rate. Since these control modes themselves are well-known techniques, detailed description is omitted. Also, since the means and methods for selecting the control mode are not within the scope of this specification, they are not mentioned in detail.

[0071] Next, with reference to the time charts of FIGS. 9 and 10, the switching operation from the unilateral drive mode to the bilateral drive mode will be described while comparing the comparative example and the first embodiment. The power supply voltage is the same, and the power distribution ratio is 1:1. The comparative example shown in FIG. 9 does not take measures to ensure continuity when switching the drive mode. On the other hand, the first embodiment shown in FIG. 10 performs the instantaneous correction and the gradual change of the power amount described above as measures to ensure continuity at the time of switching.

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

[0073] Common to FIGS. 9 and 10, the drive mode switches from the first inverter single-side drive mode to the two-side drive mode, and further switches from the two-side drive mode to the first inverter single-side drive mode. Along with this, the amplitude of the voltage across both ends of the MG coil switches from the first power supply voltage VH1 to the sum of the voltages of the two power supplies (VH1 + VH2), and further switches from the sum of the voltages of the two power supplies (VH1 + VH2) to the first power supply voltage VH1.

[0074] In the first inverter single-side 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 two-side drive mode, the sum of the currents of the two power supplies (Ib1 + Ib2) flows. Also, in the first inverter single-side drive mode, the first voltage command Vdq1 takes on a non-zero value, and the second voltage command Vdq2 is 0. In the two-side drive mode, the first voltage command Vdq1 and the second voltage command Vdq2 take on equivalent non-zero values.

[0075] When switching the driving mode, the voltage across the MG coil changes in steps. At this time, in a comparative example where no measures are taken to ensure continuity, the voltage commands Vdq1 and Vdq2 change abruptly, and fluctuations occur in torque and power as shown in the (Xc) part. That is, torque and power change discontinuously. In contrast, in the first embodiment, the first voltage command Vdq1 is instantaneously corrected for the step change in the voltage across the MG coil, and the second voltage command Vdq2 changes following it. Also, regarding the MG output, since the amount of power is gradually changed, as shown in the (Xp) part, fluctuations in torque and power do not occur when switching the driving mode. Therefore, torque and power change while maintaining continuity.

[0076] Regarding the switching operation of the driving mode in FIG. 10, it will be described in the order of numbers 1 to 8. In operation 1, the first inverter 60 is driving unidirectionally. In operation 2, based on the switching determination, the recognized power supply voltage value is switched from VH1 to (VH1 + VH2). In operation 3, based on the recognized power supply voltage values before and after the switching, the voltage command Vdq1 of the first inverter 60 is instantaneously corrected.

[0077] And based on the value indicated by (*), the value to be carried over to the next integration period is set as the integral term. As a specific example, when there is an addition term separate from the feedback control, a process such as subtracting and carrying over that value is performed, and it is set to an integral term that can maintain the continuity during the control period. 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 driving bidirectionally. In operation 6, the switching arbitration unit 303 gradually decreases 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 recognized power supply voltage value is switched from (VH1 + VH2) to VH1. In operation 8, based on the recognized power supply voltage value, the voltage command Vdq1 of the first inverter 60 is instantaneously corrected. And the value set based on the voltage command Vdq1 applied immediately after switching from the unidirectional driving mode is carried over to the next integration period.

[0079] Also, FIG. 11 shows the change in the power distribution of the inverters 60 and 70 in the MG output during the drive mode switching. In the stable stage of the first inverter single-sided drive mode, the shared power of the first inverter 60 occupies 100%. In the power quantity gradual change stage, the shared power of the second inverter 70 gradually increases. In the stable stage of the bilateral drive mode, the distribution ratio between the first inverter 60 and the second inverter 70 becomes constant.

[0080] [Method for Determining Switching between Single-Sided Drive Mode and Bilateral Drive Mode] Next, when the MG output reaches the target output, a drive mode switching determination method that is accurate (i.e., reliable) and uniquely determinable will be described. Regarding the voltage utilization rate that is a prerequisite for switching determination, first, the voltage utilization rate in a general single-power-supply and single-inverter configuration will be described.

[0081] [Single-Power-Supply and Single-Inverter Configuration] As a switching requirement for the drive mode, switching requirements corresponding to the target and scene, such as the power supply state (e.g., SOC), the temperature of the power supply, inverter, or MG, and the MG output state (e.g., voltage utilization rate), are assumed. Among these factors, the voltage utilization rate, which is an index representing the MG output state, is calculated by the following formula. The line-to-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-to-line voltage amplitude / Inverter input voltage

[0082] Here, if the voltage utilization rate is represented as VUF, the conversion coefficient as K, and the dq-axis voltage amplitude as |Vdq|, the above formula is represented as formula (2). Since the conversion coefficient K is uniquely determined once the representation method of the voltage utilization rate is determined, it is omitted in the following formulas including FIG. 12.

[0083] [Equation]

[0084] [Two-Power-Supply and Two-Inverter Configuration] In the two - side drive mode of the two - power - supply two - inverter configuration, the "voltage utilization rate used for MG control" is calculated for each inverter by dividing the line - to - line voltage of the inverter by the sum of the two - power - supply voltages, as shown in the following formula. Voltage utilization rate used for MG control = Inverter line - to - line voltage / Sum of two - power - supply voltages

[0085] The voltage utilization rate used for MG control is the voltage utilization rate from the MG perspective that is utilized for grasping the control state, and is hereinafter represented by the symbol "VUF_MG". The voltage utilization rates VUF_MG_INV1 and VUF_MG_INV2 used for MG control of each inverter are expressed by formulas (3.1) and (3.2) using the dq - axis voltages Vdq1 and Vdq2.

[0086]

Number

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

[0088] In the two - side drive mode, the voltage utilization rates VUF_MG_INV1 and VUF_MG_INV2 of both inverters rise together, and after reaching the upper limit, they decrease together. Then, when the voltage utilization rates VUF_MG_INV1 and VUF_MG_INV2 of both inverters reach the single - side switching threshold, it is switched to the single - side drive mode of the first inverter.

[0089] Also, the switching determination using the "self - inverter voltage utilization rate VUF_self" as another voltage utilization rate will be described. The self - inverter voltage utilization rate is calculated for each inverter by dividing the line - to - line voltage of the inverter by the input voltage of each inverter, as shown in the following formula. Self-inverter voltage utilization ratio = Inverter line voltage / Inverter input voltage

[0090] Hereinafter, the symbol of the self-inverter voltage utilization ratio shall be "VUF_self". The self-inverter voltage utilization ratios VUF_self_INV1 and VUF_self_INV2 of each inverter are expressed by formulas (4.1) and (4.2) using the dq-axis voltages Vdq1 and Vdq2.

[0091] [Number]

[0092] For example, when operating up to the limit of the single-sided drive mode, the upper limit threshold of the self-inverter voltage utilization ratio VUF_self means the limit of the output by the switching drive of one inverter. That is, by determining the switching timing using the self-inverter voltage utilization ratio VUF_self, it is possible to determine whether it is in the region where a desired output can be obtained by one inverter. Therefore, by comparing the self-inverter voltage utilization ratio VUF_self with the threshold value reflecting the desired voltage utilization ratio, the switching timing between the single-sided drive mode and the double-sided drive mode can be determined for the MG output state.

[0093] According to this method, even if there are errors in the sensors and variations in the device constants due to changes in the MG magnetic flux due to temperature characteristics, etc., it is possible to correctly determine whether it is the target switching point considering such a state. Also, it is preferable to provide hysteresis between the threshold value used for switching from the single-sided drive mode to the double-sided drive mode and the threshold value used for switching from the double-sided drive mode to the single-sided drive mode to prevent hunting of the switching.

[0094] Fig. 12(b) shows the operation of switching determination using the self-inverter voltage utilization factor VUF_self. In the first inverter single-sided drive mode where "VH2 = 0", the self-inverter voltage utilization factor VUF_self_INV1 of the first inverter is equal to the voltage utilization factor VUF_MG_INV1. When the self-inverter voltage utilization factor VUF_self_INV1 rises and reaches the bilateral switching threshold, it is switched to the bilateral drive mode. At this time, the self-inverter voltage utilization factor VUF_self_INV1 of the first inverter increases step by step.

[0095] The operations of the voltage utilization factors VUF_MG_INV1 and VUF_MG_INV2 in the bilateral drive mode are the same as those in Fig. 12(a). Even when the voltage utilization factors VUF_MG_INV1 and VUF_MG_INV2 of both inverters decrease from the upper limit, it has no relation to the switching determination. And when the self-inverter voltage utilization factor VUF_self_INV1 reaches the single-sided switching threshold, it is switched to the first inverter single-sided drive mode.

[0096] <Operational effects> (1) The switching arbitration unit 303 of the first embodiment arbitrates the outputs of the inverters 60 and 70 at the time of switching so as to make the MG output continuous before and after the switching of the drive mode. Thereby, the MG control device 101 can stabilize the MG output and maintain continuity at the time of switching between the single-sided drive mode and the bilateral drive mode in the configuration of two power supplies and two inverters. Furthermore, it is possible to prevent component failures due to overcurrent generated by excessive voltage application.

[0097] (2) Specifically, when switching from the single-sided drive mode to the bilateral drive mode, the switching arbitration unit 303 gradually changes and increases the power amount of the inverter on the drive start side from zero. Also, when switching from the bilateral drive mode to the single-sided drive mode, the switching arbitration unit 303 gradually changes and decreases the power amount of the inverter on the drive end side to zero. Thereby, it is possible to mitigate the output change of the inverter at the rise and fall during the drive mode switching and eliminate the fluctuation of the torque of the electric motor due to the influence of power fluctuation.

[0098] (3) The switching arbitration unit 303 performs a switching determination according to the output request for the MG80, the SOC states of the power supplies 11 and 12, or the temperatures of the power supplies 11 and 12, the inverters 60 and 70, or the MG80. Thereby, it becomes possible to determine whether or not to switch the driving mode according to the driving state.

[0099] (4) The switching arbitration unit 303 performs a switching determination between the single-side driving mode and the both-side driving mode based on the self-inverter voltage utilization rate VUF_self calculated by dividing the inverter line voltage by the inverter input voltage for at least one of the inverters. Thereby, a switching threshold can be set regardless of the power supply voltage difference, and the switching determination can be executed uniquely.

[0100] (5) According to the first embodiment, in the single-side driving mode, the output of the inverter is determined based on one of the power supply voltages, and in the both-side driving mode, it has a control configuration in which the output of each inverter is determined based on the sum of the voltages of the two power supplies. When switching the driving mode, the switching arbitration unit 303 instantaneously corrects the voltage command Vdq1 in response to a sudden change in the sum of the voltages of the two power supplies and passes it on to the next processing cycle. Thereby, the first embodiment can suppress the influence of the sudden voltage change during driving mode switching and realize stable inverter driving.

[0101] (Second Embodiment) Next, referring to FIG. 13, the second embodiment will be described. Similar to the first embodiment, the second embodiment has a control configuration in which, in the single-side driving mode, the output of the inverter is determined based on one of the power supply voltages, and in the both-side driving mode, the output of each inverter is determined based on the sum of the voltages of the two power supplies. Also, in the second embodiment, as a response means for the step change due to the momentary superposition of the output pulse voltages of the inverters 60 and 70 during driving mode switching, the switching arbitration unit 303 executes a "slow change process" that gradually changes the voltage recognition value in control with respect to the sudden change in the sum of the two power supply voltages.

[0102] Specifically, in the slow change process, the change amount per unit time of the power supply voltage recognition value is limited by an arbitrary time constant delay filter or rate processing. That is, in the first embodiment, instantaneous voltage correction is performed, while in the second embodiment, continuous voltage correction is performed to suppress output fluctuations.

[0103] Fig. 13 shows the operations of the slow change process in the scenario of transitioning from the first inverter single-sided drive mode to the double-sided drive mode and in the scenario of transitioning from the double-sided drive mode to the first inverter single-sided drive mode. The first inverter 60 executes the slow change process for operations 1 and 4, and the second inverter 70 executes the slow change process for operations 2 and 3.

[0104] When switching from the first inverter 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 the slow change process. In operation 2, the switching arbitration unit 303 gradually increases the output of the second inverter 70 from zero by the slow change process at the rising edge. Accordingly, by making the output of the first inverter 60 respond smoothly, a stable double-sided drive mode is achieved.

[0105] When switching from the double-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 the slow change process. In operation 4, the switching arbitration unit 303 gradually decreases the output of the second inverter 70 to zero by the slow change process at the falling edge. Accordingly, by making the output of the first inverter 60 respond smoothly, a stable single-sided drive mode is achieved. Therefore, the second embodiment can suppress the influence of sudden voltage changes during drive mode switching and realize stable inverter drive.

[0106] (Third Embodiment) Next, referring to FIGS. 14 to 18, as a third embodiment, a control configuration related to the switching from the one-sided drive mode by one inverter to the one-sided drive mode by the other inverter will be described. For example, if only one power source is continuously used in the one-sided drive mode under low load, the power consumption becomes uneven and the power source temperature rises. When the power source is a battery, the SOC becomes uneven and there is a risk of depletion. Therefore, it is effective to alternate the power sources used by stopping the inverter that is being driven in the one-sided drive mode and instead driving the inverter that has been stopped in the one-sided drive mode.

[0107] In such a switching from the first inverter one-sided drive mode to the second inverter one-sided drive mode, regardless of the control method, the voltage across the MG coil always changes before and after the switching due to the power supply voltage difference and various mechanical differences including the inverter. This is an inevitable problem of the two-power-source two-inverter system. And if the change in the voltage across the MG coil directly connected to the generation of the three-phase current cannot be accommodated, there will be an excess or deficiency in the voltage across the MG coil required to flow the desired current, and from the relationship between the electrical circuit and the pulse voltage output, current fluctuations are easily caused.

[0108] As shown in FIG. 14(a), the voltage amplitude across the MG coil is the voltage amplitude VH1 of the first power source 11 during the one-sided drive of the first inverter, and the voltage amplitude VH2 of the second power source 12 during the one-sided drive of the second inverter. Here, as the voltage ratio of the two power sources, the ratio of the second power source voltage VH2 to the first power source voltage VH1 is denoted as "α". For example, when the first power source voltage VH1 is 200V and the second power source voltage VH2 is 400V, α is 2.

[0109] FIG. 14(b) shows a schematic control configuration at the time of switching between the first inverter single-sided drive mode and the second inverter single-sided drive mode. When performing switching drive only with the first inverter 60, the first power supply voltage VH1 is applied as the input voltage for PWM control. On the other hand, when performing switching drive only with the second inverter 70, the second power supply voltage VH2 is applied as the input voltage for PWM control. Therefore, when switching the drive mode, if there is an excess or deficiency of the applied voltage with respect to the voltage immediately before switching, the inverter output is not appropriately taken over and current disturbance occurs.

[0110] Therefore, in the third embodiment, in order to eliminate the power supply voltage difference and the machine difference variation, during the switching between the first inverter single-sided drive mode and the second inverter single-sided drive mode, the double-sided drive mode is passed through. During the double-sided drive mode, each inverter control circuit 301, 302 generates inverter voltage commands Vdq1, Vdq2 in consideration of the power supply voltage difference and the machine difference variation.

[0111] As an example, FIG. 15(a) shows a control configuration at the time of switching from the first inverter single-sided drive mode to the second inverter single-sided drive mode. When switching from the first inverter 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 switching, by instantaneous correction of the power supply voltage recognition value.

[0112] During the double-sided drive mode, power distribution control is performed so as to gradually change the power amount of each first inverter 60. At the start of the double-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 double-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. During that time, output arbitration is performed.

[0113] When switching from the bilateral drive mode to the second inverter single-side drive mode, the instantaneous correction of the power supply voltage recognition value multiplies the ratio of the voltage recognition values before and after switching, VH2 / (VH1+VH2), which is then carried over as the voltage command Vdq2 of the second inverter 70. The value of this ratio is converted as shown in Equation (5).

[0114]

Equation

[0115] In this way, in the case of switching from the single-side drive mode by one inverter to the single-side drive mode by the other inverter, the switching arbitration unit 303 causes the voltage command Vdq1 output by the inverter on the drive end side to be carried over as the voltage command Vdq2 of the inverter on the drive start side, which is a value obtained by multiplying the voltage command Vdq1 by the correction coefficient based on the voltage ratio α of the two power supplies.

[0116] Also, as shown in FIG. 15(b), the switching arbitration unit 303 gradually reduces the output (i.e., the amount of power carried) of the first inverter 60 on the drive end side from 100% to 0% during the bilateral drive mode, and gradually increases the output of the second inverter 70 on the drive start side from 0% to 100% to carry over the amount of power. At this time, the power is gradually changed at a rate of change that allows the feedback control to follow. When the output of the first inverter 60 decreases to 0%, the switching arbitration unit 303 pauses the first inverter 60.

[0117] Referring to the flowchart of FIG. 16, the drive mode switching process according to the third embodiment will be described. In FIG. 16, the steps corresponding to the steps in FIG. 6 will be appropriately omitted from the description. The switching determination from the single-side drive mode to the bilateral drive mode in S10 and each process from the voltage recognition value setting to the gradual change of the amount of power in S21 to S24 are basically the same as those in FIG. 6.

[0118] In the switching determination of S10, when the temperature Hb1 of the first power supply 11 rises excessively, for example, the switching arbitration unit 303 pauses the first inverter 60 that is driving on one side, and instead makes a switching determination to drive the inverter that has been paused on one side. Here, "when the temperature rises excessively" means a case where the temperature exceeds the allowable upper limit that is even higher than the upper limit of the appropriate range shown in S12 of FIG. 8. In this case, not only is the load on the first power supply 11 reduced in the bilateral drive mode, but it is also preferable to more actively pause the first inverter 60. Note that when the temperature Hinv1 of the first inverter 60 rises excessively, it is also preferable to take the same measures.

[0119] Also, when the SOC of the first power supply 11 falls below the allowable lower limit that is even lower than the lower limit of the appropriate range shown in S13 of FIG. 8, the switching arbitration unit 303 preferably pauses the first inverter 60 by switching to the single-sided drive mode of the second inverter without staying in the bilateral drive mode.

[0120] In S25, the switching arbitration unit 303 is set to switch the roles of the torque management circuit and the power management circuit by the 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 supplies 11 and 12 to the two inverters 60 and 70.

[0121] The inverter control circuit that switches from feedback control to feedforward control starts power control from that point because it inherits the value of the integral term as the initial value during power control. Also, the inverter control circuit that switches from feedforward control to feedback control substitutes the voltage command used in power control into the integral term and starts feedback control with this as the initial value because it inherits the voltage command used in power control.

[0122] In S30, similar to S10, a switching determination from the bilateral drive mode to the unilateral drive mode is performed. When the switching determination is satisfied and it is determined as YES in S30, in S41 to S44, each process from the voltage recognition value setting to the power gradual change is performed in the same manner as in S21 to S24. Further, in S45, similar to S25, the role setting of the two inverter control circuits 301 and 302 is performed.

[0123] The time chart of FIG. 17 shows the switching operation from the first inverter unilateral drive to the second inverter unilateral drive when the voltages of the two power supplies are equal (that is, α = 1), and this switching operation will be described for each of the times numbered 1 to 9. In operation 1, the first inverter 60 is driving unilaterally. 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 driving bilaterally. In operation 6, the switching arbitration unit 303 gradually increases the output of the second inverter 70 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, based on the instantaneous correction based on the power supply voltage recognition value, the value obtained by multiplying the voltage command Vdq1 output by the first inverter 60 by the correction coefficient based on the voltage ratio α of the two power supplies is taken over 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 the feedforward control-based power control to the feedback control method.

[0126] The time chart of FIG. 18 shows the switching operation from the one-sided drive of the first inverter to the one-sided drive of the second inverter when the voltages of the two power supplies are different. In this example, the second power supply voltage VH2 is higher than the first power supply voltage VH1, and the voltage ratio α of the two power supplies is greater than 1. Also, the power distribution ratio is 1:1. The numbers 1 to 9 of the timing of each operation follow FIG. 17, and only the differences from FIG. 17 will be described.

[0127] When switching from the one-sided drive mode of the first inverter to the both-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 perspective of MG due to the instantaneous correction in operation 3 appears relatively large. When switching from the both-sided drive mode to the one-sided drive mode of the second inverter 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 perspective of MG due to the instantaneous correction in operation 8 appears relatively small. At this time, the value multiplied by the 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] Similar to the first embodiment, the third embodiment can eliminate output fluctuations during drive mode switching and can avoid only one of the power supplies reaching SOC depletion during the continuation of the low-load and low-loss one-sided drive mode.

[0129] Also, at least one of the inverter control circuits operates as a power management circuit, and the switching arbitration unit 303 switches the role of the power management circuit between the two inverter control circuits 301 and 302 during drive mode switching and relays the previous control state to the other side. Thereby, the inverter control circuit responsible for power distribution in the both-sided drive mode can be fixed, and the number of state transitions can be reduced to simplify the configuration.

[0130] Note that the point of swapping the roles of the power management circuits between the two inverter control circuits 301 and 302 is the same for the above-described first and second embodiments. That is, 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, the roles of the torque management circuit and the power management circuit may be swapped.

[0131] (Fourth Embodiment) Next, referring to FIGS. 19 to 21, the fourth embodiment will be described. FIG. 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 source 13. Regarding the reference numerals of the capacitor 16, the voltage sensor 18, and the temperature sensor 861 provided corresponding to the common power source 13, the reference numerals of the respective components corresponding to the first power source 11 of the first embodiment are used. The voltage sensor 18 detects the voltage VH of the common power source 13, and the temperature sensor 861 detects the temperature Hb of the common power source 13. Also, the current flowing through the common power source 13 is denoted as the common power source current Ib. The power Pb of the common power source 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 to each other by a common high-potential side wiring Pcom, and the low-potential side wirings N1 and N2 are connected to each other by a common low-potential side wiring Ncom. Also, 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 of FIG. 19, the switch 14 is provided on the common high-potential side wiring Pcom.

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

[0134] The sum of the share power P_INV1 of the first inverter 60 and the share power P_INV2 of the second inverter 70 is approximately equal to the power Pb of the common power supply 13, although there is a slight difference considering losses due to wiring and the like. That is, it is expressed as "Pb ≒ P_INV1 + P_INV2". Using current and voltage, it is expressed as "Ib × VH ≒ Ib1 × VH + Ib2 × VH".

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

[0136] The MG control device 104 can operate the other inverter in a single - side drive mode in a star - connection circuit configured by connecting the neutral point of one inverter in a state where the switch 14 is open (i.e., off). Also, the MG control device 104 can operate in a both - side drive mode in an H - bridge circuit configured by the first switching elements 61 to 66 and the second switching elements 71 to 76 of the corresponding phases in a state where the switch 14 is closed (i.e., on). Thus, the technology of switching between the star - connection circuit and the H - bridge circuit by operating the switch 14 is disclosed in Japanese Patent Application Laid - Open No. 2017 - 175747 and the like.

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

[0138] FIG. 20(b) shows switching driving in the bilateral driving mode in the H-bridge circuit. For the U-phase open winding 81, an H-bridge circuit is constituted by the switching elements 61, 64 of the first inverter 60 and the switching elements 71, 74 of the second inverter 70. For the V-phase open winding 82, an H-bridge circuit is constituted by the switching elements 62, 65 of the first inverter 60 and the switching elements 72, 75 of the second inverter 70. For the W-phase open winding 83, an H-bridge circuit is constituted by the switching elements 63, 66 of the first inverter 60 and the switching elements 73, 76 of the second inverter 70. By driving each phase H-bridge circuit in the bilateral driving mode, a double value of the common power supply voltage VH is applied to the MG80.

[0139] The time chart of FIG. 21 shows the driving mode switching operation according to the fourth embodiment. Similar to FIG. 10 of the first embodiment, the driving mode switches from the first inverter single-side driving mode to the bilateral driving mode, and further switches from the bilateral driving mode to the first inverter single-side driving mode. The changes in the torque, rotational speed, and MG output of the MG80 are the same as those in FIG. 10. On the other hand, regarding the amplitude of the voltage across the MG coil, the first power supply voltage VH1 in FIG. 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 a double value of the common power supply voltage (VH × 2).

[0140] Also, for the power supply current in FIG. 10, in FIG. 21, although the profile of the change is the same, instead of the power supply current, the change in the inverter input current or the inverter share power proportional to the input current is shown. The sum of the currents of the two power supplies (Ib1 + Ib2) in FIG. 10 is replaced by the common power supply current Ib. In proportion to the change in the common power supply current Ib, the sum of the share powers of the two inverters 60, 70 (P_INV1 + P_INV2) changes. Since the instantaneous correction of the voltage commands Vdq1, Vdq2 at the time of switching the driving mode is the same as that in FIG. 10, it is omitted.

[0141] In this switching control, the MG control device 104 determines the output of one of the inverters (for example, the first inverter 60) based on the common power supply voltage VH in the single-sided drive mode, and determines the outputs of the inverters 60 and 70 based on twice the value of the common power supply voltage (VH × 2) in the double-sided drive mode. When switching the 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 output of the inverter, that is, a sudden change from VH to (VH × 2), or from (VH × 2) to VH, and passes it on to the next processing cycle.

[0142] Also, the slow change process according to the second embodiment may be combined with the above switching control in the fourth embodiment. In that case, when switching the drive mode, the switching arbitration unit 303 executes a "slow change process" that gradually changes the voltage recognition value for control with respect to a sudden change in the voltage used to determine the output of the inverter.

[0143] As described above, in the fourth embodiment, in a system that drives the MG80 of the open windings 81, 82, and 83 using one common power supply 13 and two inverters 60 and 70, the single-sided drive mode in the star connection circuit and the double-sided drive mode in the H-bridge circuit are switched. Then, when switching the drive mode, the power P_INV1 and P_INV2 shared by the inverters 60 and 70 are output-arbitrated according to the drive mode after switching.

[0144] Thereby, in the drive region with low MG output, one of the inverters can be stably stopped to reduce losses. Also, when the thermal load of one of the inverters is high in the single-sided drive mode or the double-sided drive mode, the thermal load can be dispersed by stably stopping one of the inverters on one side or shifting to the double-sided drive mode.

[0145] In addition, the switching arbitration unit 303 of the fourth embodiment exhibits the same effects as the effects (2) to (4) of the first embodiment. That is, when switching from the single-sided drive mode to the double-sided drive mode, the switching arbitration unit 303 gradually increases the amount of power of the drive start-side inverter from zero. Also, when switching from the double-sided drive mode to the single-sided drive mode, the switching arbitration unit 303 gradually decreases the amount of power of the drive end-side inverter to zero. Thereby, the output change of the inverter during the rise and fall at the time of drive mode switching can be mitigated, and it is possible to eliminate the variation of the torque of the electric motor due to the influence of power fluctuation.

[0146] Also, the switching arbitration unit 303 performs switching determination according to the output request for MG80, the SOC state of the common power supply 13, or the temperature of the common power supply 13, the inverters 60, 70, or MG80. Thereby, it becomes possible to determine whether or not to switch the drive mode according to the drive state.

[0147] Also, the switching arbitration unit 303 performs switching determination between the single-sided drive mode and the double-sided drive mode based on the self-inverter voltage utilization factor VUF_self calculated by dividing the inverter line voltage by the inverter input voltage for at least one of the inverters. Thereby, it is possible to set the switching threshold regardless of the power supply voltage difference, and it is possible to execute the switching determination uniquely.

[0148] Furthermore, also in the fourth embodiment, in the same manner as in the above-described embodiment, at least one of the inverter control circuits operates as a power management circuit. In that case, at the time of drive mode switching, the switching arbitration unit 303 can switch the role of the power management circuit between the two inverter control circuits 301 and 302 and transfer the immediately preceding control state to the other side.

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

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

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

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

[0153] In addition, the configurations such as the control unit 300 and the temperature sensors 861 to 865 of the fifth embodiment are the same as those of the first embodiment. In the fifth embodiment, the drive mode switching control according to the first to third embodiments can be applied almost as it is, and the same operational effects can be obtained.

[0154] (Sixth Embodiment) Next, referring to FIGS. 23 and 24, the sixth embodiment will be described. FIG. 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 in the fourth embodiment shown in FIG. 19, two inverters 60 and 70 are connected to one common power source 13. The meanings of the first inverter input current Ib1, the second inverter input current Ib2, and the common power source voltage VH are interpreted according to the fourth embodiment. And the MG90 of the sixth embodiment is a six-phase dual-winding motor as in the fifth embodiment.

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

[0156] The time chart of FIG. 24 shows the drive mode switching operation according to the sixth embodiment. According to FIGS. 10 and 21 of the first and fourth embodiments, the drive mode switches from the first inverter single-side drive mode to the both-side drive mode, and further switches from the both-side drive mode to the first inverter single-side drive mode. The changes in the torque, rotational speed, and MG output of the MG80 are the same as those in FIGS. 10 and 21, and the inverter input current or the inverter-shared power proportional to the input current is the same as that in FIG. 21.

[0157] On the other hand, the amplitude of the voltage across the MG coil remains constant at the common power source voltage VH regardless of the switching between the single-side drive mode and the both-side drive mode. Therefore, in the sixth embodiment, since there is no sudden change in the voltage used to determine the output of the inverter, it is not necessary to consider instantaneous correction or slow change processing of the voltage command.

[0158] Thus, in the sixth embodiment, in a system that drives the six-phase dual-winding MG80 using a common power source 13 for one winding and two inverters 60 and 70, the single-side drive mode and the both-side drive mode are switched. Then, when switching the drive mode, the power P_INV1 and P_INV2 shared by each inverter 60 and 70 are output-adjusted according to the drive mode after switching.

[0159] Accordingly, based on the element loss characteristics and the shared current amount, in a scene where it is possible to operate with lower loss by deactivating the inverter, the inverter on one side can be stably deactivated, or the loss can be reduced by shifting to the both-side drive mode. Further, when the thermal load of one inverter is high in the single-side drive mode or the both-side drive mode, the thermal load can be dispersed by stably deactivating the inverter on one side or shifting to the both-side drive mode.

[0160] In addition, the switching arbitration unit 303 of the sixth embodiment has the same effects as the effects (2) to (4) of the first embodiment. This is as described in the fourth embodiment. Also, the swapping of the roles of the power management circuit between the two inverter control circuits 301 and 302 is the same as in the above embodiments.

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

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

[0163] (c) The number of phases of the open winding of the motors in the first and fourth embodiments is not limited to three phases and may be four phases or more. Also, a configuration in which two-phase open windings are bridge-connected may be used.

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

[0165] (e) The two-power-supply two-inverter type motor drive device is applicable to pure electric vehicles such as electric vehicles and fuel cell vehicles, electric-rich hybrid power trains such as PHV (Plug-in Hybrid) and range extenders, and even light electrified vehicles such as 12 - 48V ISG (Integrated Starter Generator). This technology does not use any boost circuits with reactors, which are known as prior art, and by serializing the power supply voltage, it is a voltage-type circuit topology applicable to applications that achieve high efficiency and high output. This technology is suitable for applications that require high output even in regions where it is thermally difficult to achieve with conventional boost circuits or large current type inverters in each vehicle, and enables more efficient operation than conventional power trains.

[0166] As described above, the present invention is not limited to the above embodiments and can be implemented in various forms without departing from the gist thereof.

Description of Reference Numerals

[0167] 101, 104... MG control device (motor drive device), 11... First power supply (power supply), 12... Second 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 arbitration unit, 60... First inverter, 61 - 66... First switching element, 70... Second inverter, 71 - 76... Second switching elements, 80... MG (motor), 81, 82, 83... Open windings (windings).

Claims

1. An electric motor drive device for controlling the driving of an electric motor (80) having windings (81, 82, 83) connected to two inverters each connected to a power source (11, 12, 13), comprising: a first inverter (60) which is one of the two inverters and to which DC power is input from the power source, 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, receives DC power from the power source, 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) including 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 switching 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 outputs of the inverters at the time of switching so as to make the outputs of the motor continuous before and after the switching of the drive mode; Equipped with At least one of the inverter control circuits has a function of adjusting the amount of power supplied from the power source to the two inverters, The switching arbitration unit is a determination is made to switch between the single-sided driving mode and the double-sided driving mode based on an own inverter voltage utilization rate calculated by dividing an inverter line voltage by an inverter input voltage for at least one of the inverters, such that when the own inverter voltage utilization rate in the single-sided driving mode increases and reaches a double-sided switching threshold, the mode is switched to the double-sided driving mode, and when the own inverter voltage utilization rate in the double-sided driving mode decreases and reaches a single-sided switching threshold, the mode is switched to the single-sided driving mode; When switching from the one-sided driving mode to the two-sided driving mode, the amount of power of the drive start side inverter which starts switching driving from a rest state is gradually increased from zero; When switching from the double-sided driving mode to the single-sided driving mode, the motor driving device gradually reduces, to zero, the amount of power of the inverter on the driving end side that ends switching driving and transitions to a pause state.

2. An electric motor drive device for controlling the driving of an electric motor (80) having windings (81, 82, 83) connected to two inverters each connected to a common power source (13), comprising: a first inverter (60) which is one of the two inverters and 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 and 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 common high potential side wiring (Pcom) that connects high potential side wirings (P1, P2) of the first inverter and the second inverter to each other; a common low potential side wiring (Ncom) that connects the low potential side wirings (N1, N2) of the first inverter and the second inverter to each other; a switch (14) provided on at least one of the common high potential side wiring or the common low potential side wiring and capable of interrupting a current path; a control unit (300) including 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 switching 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 outputs of the inverters at the time of switching so as to make the outputs of the motor continuous before and after the switching of the drive mode; Equipped with In a star-connected circuit in which one of the inverters is connected to a neutral point with the switch open, the other inverter can be operated in the one-sided drive mode, With the switches closed, an H-bridge circuit formed by the first switching elements and the second switching elements of the corresponding phases can operate in the double-sided drive mode, At least one of the inverter control circuits has a function of adjusting the amount of power supplied from the common power source to the two inverters, The switching arbitration unit is a determination is made to switch between the single-sided driving mode and the double-sided driving mode based on an own inverter voltage utilization rate calculated by dividing an inverter line voltage by an inverter input voltage for at least one of the inverters, such that when the own inverter voltage utilization rate in the single-sided driving mode increases and reaches a double-sided switching threshold, the mode is switched to the double-sided driving mode, and when the own inverter voltage utilization rate in the double-sided driving mode decreases and reaches a single-sided switching threshold, the mode is switched to the single-sided driving mode; When switching from the one-sided driving mode to the two-sided driving mode, the amount of power of the drive start side inverter which starts switching driving from a rest state is gradually increased from zero; When switching from the double-sided driving mode to the single-sided driving mode, the motor driving device gradually reduces, to zero, the amount of power of the inverter on the driving end side that ends switching driving and transitions to a pause state.

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

4. The switching arbitration unit is When the first inverter switches from the single-sided driving mode to the double-sided driving mode, the voltage command value is corrected by twice the voltage of the common power source; 4. The electric 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, an output of the inverter is determined based on a voltage of the common power supply in the single-sided drive mode, and an output of each of the inverters is determined based on twice the voltage of the common power supply in the double-sided drive mode, 4. The electric motor drive device according to claim 3, wherein when the first inverter switches from the one-sided driving mode to the two-sided driving mode, the switching arbitration unit executes a slow-change process that continuously changes the voltage value over time from the voltage of the common power source to a value twice the voltage of the common power source.

6. An electric motor drive device for controlling the driving of an electric motor (80) having windings (81, 82, 83) connected to two inverters each connected to a plurality of power sources (11, 12), comprising: a first inverter (60) which is one of the two inverters and receives DC power from a predetermined number of first power sources (11) connected among the plurality of power sources, 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; a second inverter (70), which is the other of the two inverters and receives DC power from a second power source (12) among the multiple power sources that is not connected to the first inverter, has multiple 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) including 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 switching 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 outputs of the inverters at the time of switching so as to make the outputs of the motor continuous before and after the switching of the drive mode; Equipped with At least one of the inverter control circuits has a function of adjusting the amount of power supplied from the plurality of power sources to the two inverters, The switching arbitration unit is a determination is made to switch between the single-sided driving mode and the double-sided driving mode based on an own inverter voltage utilization rate calculated by dividing an inverter line voltage by an inverter input voltage for at least one of the inverters, such that when the own inverter voltage utilization rate in the single-sided driving mode increases and reaches a double-sided switching threshold, the mode is switched to the double-sided driving mode, and when the own inverter voltage utilization rate in the double-sided driving mode decreases and reaches a single-sided switching threshold, the mode is switched to the single-sided driving mode; When switching from the one-sided driving mode to the two-sided driving mode, the amount of power of the drive start side inverter which starts switching driving from a rest state is gradually increased from zero; When switching from the double-sided driving mode to the single-sided driving mode, the motor driving device gradually reduces, to zero, the amount of power of the inverter on the driving end side that ends switching driving and transitions to a pause state.

7. In the control configuration, an output of the inverter is determined based on a voltage of the first power source in the single-sided drive mode, and an output of each of the inverters is determined based on a sum of voltages of the plurality of power sources in the double-sided drive mode, The electric motor drive device according to claim 6 , wherein the switching arbitration unit corrects a voltage command to the inverter operating in the one-sided drive mode when the drive mode is switched, and carries it over to a next processing cycle.

8. If the voltage of the first power supply is VH1, the voltage of the second power supply is VH2, and the value of the voltage command is Vdq, then The switching arbitration unit is When the first inverter switches from the one-sided driving mode to the two-sided driving mode, the voltage command value is corrected by equation (1.1); 8. The electric motor drive device according to claim 7, wherein when the double-sided drive mode is switched to the single-sided drive mode, the value of the voltage command is corrected by equation (1.2). [0010]

9. In the control configuration, an output of the inverter is determined based on a voltage of the first power source in the single-sided drive mode, and an output of each of the inverters is determined based on a sum of voltages of the plurality of power sources in the double-sided drive mode, 8. The electric motor drive device according to claim 7, wherein when the first inverter switches from the one-sided driving mode to the two-sided driving mode, the switching arbitration unit executes a slow-change process that continuously changes a voltage value over time from the voltage of the first power source to a value that becomes the sum of the voltages of the multiple power sources.

10. A motor drive device for controlling the driving of an electric motor (80) having an electric motor (81, 82, 83) having windings (81, 82, 83) connected to two inverters each connected to a common power source (13), comprising: a first inverter (60) which is one of the two inverters and 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 and 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 common high potential side wiring (Pcom) that connects high potential side wirings (P1, P2) of the first inverter and the second inverter to each other; a common low potential side wiring (Ncom) that connects the low potential side wirings (N1, N2) of the first inverter and the second inverter to each other; a switch (14) provided on at least one of the common high potential side wiring or the common low potential side wiring and capable of interrupting a current path; a control unit (300) including 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 switching 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 outputs of the inverters at the time of switching so as to make the outputs of the motor continuous before and after the switching of the drive mode; Equipped with In a star-connected circuit in which one of the inverters is connected to a neutral point with the switch open, the other inverter can be operated in the one-sided drive mode, With the switches closed, an H-bridge circuit formed by the first switching elements and the second switching elements of the corresponding phases can operate in the double-sided drive mode, At least one of the inverter control circuits has a function of adjusting the amount of power supplied from the common power source to the two inverters, In the control configuration, an output of the inverter is determined based on a voltage of the common power supply in the single-sided drive mode, and an output of each of the inverters is determined based on twice the voltage of the common power supply in the double-sided drive mode, The electric motor drive device, wherein the switching arbitration unit corrects a 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.

11. The switching arbitration unit is When the first inverter switches from the single-sided driving mode to the double-sided driving mode, the voltage command value is corrected by twice the voltage of the common power source; 11. The electric motor drive device according to claim 10, 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.

12. In the control configuration, an output of the inverter is determined based on a voltage of the common power supply in the single-sided drive mode, and an output of each of the inverters is determined based on twice the voltage of the common power supply in the double-sided drive mode, The electric motor drive device according to claim 10, wherein when the first inverter switches from the one-sided driving mode to the two-sided driving mode, the switching arbitration unit executes a slow change process that continuously changes the voltage value over time from the voltage of the common power source to a value twice the voltage of the common power source.

13. An electric motor drive device for controlling the driving of an electric motor (80) having windings (81, 82, 83) connected to two inverters each connected to a plurality of power sources (11, 12), comprising: a first inverter (60) which is one of the two inverters and receives DC power from a predetermined number of first power sources (11) connected among the plurality of power sources, 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; a second inverter (70), which is the other of the two inverters and receives DC power from a second power source (12) among the multiple power sources that is not connected to the first inverter, has multiple 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) including 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 switching 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 outputs of the inverters at the time of switching so as to make the outputs of the motor continuous before and after the switching of the drive mode; Equipped with At least one of the inverter control circuits has a function of adjusting the amount of power supplied from the plurality of power sources to the two inverters, In the control configuration, an output of the inverter is determined based on a voltage of the first power source in the single-sided drive mode, and an output of each of the inverters is determined based on a sum of voltages of the plurality of power sources in the double-sided drive mode, The electric motor drive device, wherein the switching arbitration unit corrects a 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.

14. If the voltage of the first power supply is VH1, the voltage of the second power supply is VH2, and the value of the voltage command is Vdq, then The switching arbitration unit is When the first inverter switches from the one-sided driving mode to the two-sided driving mode, the voltage command value is corrected by equation (1.1); The electric motor drive device according to claim 13, wherein when switching from the double-sided drive mode to the single-sided drive mode, the value of the voltage command is corrected by equation (1.2). [0025]

15. In the control configuration, an output of the inverter is determined based on a voltage of the first power source in the single-sided drive mode, and an output of each of the inverters is determined based on a sum of voltages of the plurality of power sources in the double-sided drive mode, 14. The electric motor drive device according to claim 13, wherein when the first inverter switches from the one-sided driving mode to the two-sided driving mode, the switching arbitration unit executes a slow-change process that continuously changes a voltage value over time from a voltage of the first power source to a value that becomes a sum of the voltages of the multiple power sources.

Images