Motor control device

Abstract

A motor controller (1) controls a first motor (M1) and a second motor (M2) having a shared output shaft. The motor controller includes a first control unit (10a) that has a voltage conversion circuit (16) converting a first voltage output from a first power source (PS1) into a predetermined voltage and controls the first motor by using the predetermined voltage converted by the voltage conversion circuit, and a second control unit (10b) that controls the second motor by using a second voltage output from a second power source (PS2).

Description

[Technical Field]

[0001] The present disclosure relates to a motor control device. [Background technology]

[0002] An electric power steering device is a device that applies a steering assist force to the steering mechanism of a vehicle such as an automobile, and includes a motor that generates a steering assist torque for the steering and a motor control device that controls the motor. The motor control device of the electric power steering device calculates a command current value for the motor to generate the necessary steering assist torque, and outputs a motor current based on the calculated command current value to the motor.

[0003] Some recent vehicles are equipped with automatic steering systems that assist the driver in driving. In vehicles equipped with such automatic steering systems, the electric power steering device is controlled to improve the driver's steering feel or to perform automatic steering. Specifically, a motor control device of the electric power steering device controls the motor based on a control amount based on the driver's steering or a control amount based on the surrounding environment of the vehicle measured by a measuring means such as a camera or radar.

[0004] The following Patent Document 1 discloses an electric power steering device that has redundancy by providing two systems of motors and motor control devices. In this electric power steering device, even if a failure occurs in one of the two systems, control is performed by the other system, so the function of the electric power steering device can be maintained. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2020-195236 Summary of the Invention [Problem to be solved by the invention]

[0006] In an electric power steering device having two systems of motors and motor control devices, the voltages of the external power supplies for each system may differ. In such cases, the thickness or number of windings of the motor must be changed depending on the voltage of the external power supply, which results in different characteristics for the motors in each system. This can lead to a problem of deterioration in torque ripple or noise and vibration (NV) performance, even if the motors in each system output the same motor output.

[0007] The present disclosure has been made in consideration of the above circumstances, and aims to provide a motor control device that can improve torque ripple or NV performance even when different voltages are supplied to multiple systems that control the motor. [Means for solving the problem]

[0008] In order to solve the above problem, a motor control device according to one aspect of the present disclosure is a motor control device that controls a first motor and a second motor that share an output shaft, and has a voltage conversion circuit that converts a first voltage output from a first power source into a predetermined voltage, and is equipped with a first control unit that controls the first motor using the predetermined voltage converted by the voltage conversion circuit, and a second control unit that controls the second motor using a second voltage output from a second power source. [Effects of the Invention]

[0009] According to the present disclosure, there is an advantage that torque ripple or NV performance can be improved even when different voltages are supplied to multiple systems that control a motor. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a block diagram showing a configuration of a main part of a motor control device according to a first embodiment of the present disclosure. [Figure 2]1 is a plan view of a substrate illustrating an example of mounting the motor control device in accordance with embodiment 1 of the present disclosure. [Figure 3] FIG. 10 is a block diagram showing a configuration of a main part of a motor control device according to a second embodiment of the present disclosure. [Figure 4] FIG. 10 is a plan view of a substrate illustrating an example of mounting a motor control device according to a second embodiment of the present disclosure. [Figure 5] FIG. 11 is a block diagram showing a configuration of a main part of a motor control device according to a third embodiment of the present disclosure. [Figure 6] FIG. 11 is a plan view of a substrate illustrating an example of mounting a motor control device according to a third embodiment of the present disclosure. [Figure 7] FIG. 10 is a block diagram showing a configuration of a main part of a motor control device according to a fourth embodiment of the present disclosure. [Figure 8] FIG. 11 is a block diagram showing a configuration of a main part of a motor control device according to a fifth embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, motor control devices according to embodiments of the present disclosure will be described in detail with reference to the drawings.

[0012] First Embodiment Figure 1 is a block diagram showing the configuration of a main part of a motor control device according to a first embodiment of the present disclosure. The motor control device 1 shown in Figure 1 is provided in, for example, an electric power steering device that applies a steering assist force to the steering mechanism of a vehicle such as an automobile. As shown in Figure 1, the motor control device 1 of this embodiment includes a control unit 10a (first control unit), a control unit 10b (second control unit), and an inter-system communication circuit 20, and controls a motor M1 (first motor) and a motor M2 (second motor).

[0013] The control unit 10a operates on power supplied from an external power source PS1 (first power source) and controls the motor M1 based on a signal output from an external interface IF1. The control unit 10b operates on power supplied from an external power source PS2 (second power source) and controls the motor M2 based on a signal output from an external interface IF2. The control unit 10a and the motor M1 form a first system SY1, and the control unit 10b and the motor M2 form a second system SY2. Details of the control units 10a and 10b will be described later.

[0014] The external power supplies PS1 and PS2 are DC power supplies with different output voltages. The output voltage of the external power supply PS1 is higher than the output voltage of the external power supply PS2. For example, the external power supply PS1 is a DC power supply with an output voltage of 48 V, and the external power supply PS2 is a DC power supply with an output voltage of 12 V. The external power supplies PS1 and PS2 are connected to different grounds. For example, the external power supply PS1 is connected to ground G1, and the external power supply PS2 is connected to ground G2. Note that in FIG. 1, for ease of understanding, ground G1 and ground G2 are indicated by different symbols.

[0015] The external interfaces IF1 and IF2 are, for example, circuits provided in the vehicle and serve as interfaces for the control units 10a and 10b. The external interfaces IF1 and IF2 output an ignition signal indicating that the driver of the vehicle has operated the ignition key, a torque sensor signal indicating the driver's steering torque, and a CAN (Controller Area Network) signal indicating vehicle conditions such as vehicle speed and engine speed.

[0016] The motors M1 and M2 are motors of the same specifications that share an output shaft. The motors M1 and M2 are mounted on the steering column or rack shaft of the vehicle and generate steering assist torque for the steering under the control of the motor control device 1. The motors M1 and M2 are, for example, three-phase brushless motors having three-phase windings composed of a U-phase winding, a V-phase winding, and a W-phase winding. The motors M1 and M2 may be brushed motors or multi-phase motors having multi-phase windings with three or more phases.

[0017] The control unit 10a includes a power supply circuit 11a, an interface circuit 12a, a microcomputer 13a, a motor driver 14a, a motor drive circuit 15a, and a step-down circuit (voltage conversion circuit) 16. The ground of the control unit 10a is ground G1, and the power supply circuit 11a, the interface circuit 12a, the microcomputer 13a, the motor driver 14a, the motor drive circuit 15a, and the step-down circuit 16 are connected to ground G1.

[0018] The step-down circuit 16 is connected to the external power supply PS1 and steps down the output voltage (first voltage) of the external power supply PS1 to a predetermined voltage. For example, the step-down circuit 16 steps down the output voltage (48 [V]) of the external power supply PS1 to the same voltage (12 [V]) as the output voltage of the external power supply PS2. The voltage stepped down by the step-down circuit 16 is applied to the power supply circuit 11a, the motor driver 14a, and the motor drive circuit 15a.

[0019] The power supply circuit 11a is connected to the output of the step-down circuit 16, and generates a voltage referenced to ground G1 from the voltage stepped down by the step-down circuit 16. The voltage generated by the power supply circuit 11a is, for example, 5 V. The voltage generated by the power supply circuit 11a is applied to the microcomputer 13a and the motor driver 14a.

[0020] The interface circuit 12a is connected to the external interface IF1. The interface circuit 12a receives various signals output from the external interface IF1 and outputs them to the microcomputer 13a. The interface circuit 12a also outputs various signals output from the microcomputer 13a to the external interface IF1.

[0021] The microcomputer 13a operates using the voltage generated by the power supply circuit 11a and controls the motor M1 based on various signals output from the interface circuit 12a. Specifically, the microcomputer 13a calculates the required torque using a torque sensor signal output from the interface circuit 12a and a CAN signal indicating vehicle conditions such as vehicle speed and engine RPM, and outputs the motor control amount to the motor driver 14a. The microcomputer 13a also communicates with a microcomputer 13b (details of which will be described later) provided in the control unit 10b via the inter-system communication circuit 20.

[0022] The motor driver 14a operates using the voltage generated by the power supply circuit 11a, and generates a drive signal for driving the motor drive circuit 15a under the control of the microcomputer 13a. Specifically, the motor driver 14a generates a drive signal according to the motor control amount output from the microcomputer 13a and outputs the drive signal to the motor drive circuit 15a.

[0023] Motor drive circuit 15a drives motor M1 based on a drive signal output from motor driver 14a. Motor drive circuit 15b includes, for example, an inverter that converts DC power supplied from step-down circuit 16 into AC power and supplies the converted AC power to motor M1. This inverter may include, for example, a pair of switching elements Q11 corresponding to the U phase, a pair of switching elements Q12 corresponding to the V phase, and a pair of switching elements Q13 corresponding to the W phase (see FIG. 2). One of the pair of switching elements corresponding to each phase is used as the switching element of the upper arm, and the other is used as the switching element of the lower arm.

[0024] The switching elements may be, for example, metal-oxide-semiconductor field-effect transistors (MOSFETs). In addition to MOSFETs, semiconductor switches such as insulated gate bipolar transistors (IGBTs) and bipolar transistors may also be used.

[0025] The control unit 10b includes a power supply circuit 11b, an interface circuit 12b, a microcomputer 13b, a motor driver 14b, and a motor drive circuit 15b. The ground of the control unit 10b is ground G2, and the power supply circuit 11b, the interface circuit 12b, the microcomputer 13b, the motor driver 14b, and the motor drive circuit 15b are connected to ground G2. In other words, the control units 10a and 10b include grounds G1 and G2 that are separated from each other.

[0026] The power supply circuit 11b is connected to an external power supply PS2 and generates a voltage based on the output voltage (second voltage) of the external power supply PS2 and grounded at G2. The voltage generated by the power supply circuit 11b is, for example, 5 V. The voltage generated by the power supply circuit 11b is applied to the microcomputer 13b and the motor driver 14b.

[0027] The interface circuit 12b is connected to the external interface IF2. The interface circuit 12b receives various signals output from the external interface IF2 and outputs them to the microcomputer 13b. The interface circuit 12b also outputs various signals output from the microcomputer 13b to the external interface IF2.

[0028] The microcomputer 13b operates using the voltage generated by the power supply circuit 11b and controls the motor M2 based on various signals output from the interface circuit 12b. Specifically, the microcomputer 13b calculates the required torque using the torque sensor signal output from the interface circuit 12b and a CAN signal indicating vehicle conditions such as vehicle speed and engine RPM, and outputs the motor control amount to the motor driver 14b. The microcomputer 13b also communicates with the microcomputer 13a provided in the control unit 10a via the inter-system communication circuit 20.

[0029] The motor driver 14b operates using the voltage generated by the power supply circuit 11b, and generates a drive signal for driving the motor drive circuit 15b under the control of the microcomputer 13b. Specifically, the motor driver 14b generates a drive signal according to the motor control amount output from the microcomputer 13b and outputs the drive signal to the motor drive circuit 15b.

[0030] Motor drive circuit 15b drives motor M2 based on a drive signal output from motor driver 14b. Motor drive circuit 15b includes, for example, an inverter that converts DC power supplied from external power supply PS2 into AC power and supplies the converted AC power to motor M2. This inverter may include, for example, a pair of switching elements Q21 corresponding to the U phase, a pair of switching elements Q22 corresponding to the V phase, and a pair of switching elements Q23 corresponding to the W phase (see FIG. 2). Note that one of the pair of switching elements corresponding to each phase is used as the switching element of the upper arm, and the other is used as the switching element of the lower arm.

[0031] The switching elements may be, for example, MOSFETs, similar to the switching elements provided in the motor drive circuit 15a of the control unit 10a. Note that, instead of MOSFETs, semiconductor switches such as IGBTs and bipolar transistors may also be used.

[0032] The inter-system communication circuit 20 is a circuit that realizes communication between the microcomputer 13a of the control unit 10a provided in the first system SY1 and the microcomputer 13b of the control unit 10b provided in the second system SY2. The inter-system communication circuit 20 is provided, for example, to make the steering assist torque generated by the motor M1 of the first system SY1 equal (or approximately equal) the steering assist torque generated by the motor M2 of the second system SY2.

[0033] FIG. 2 is a plan view of a substrate illustrating an example implementation of a motor control device according to a first embodiment of the present disclosure. The substrate is made of an insulating material such as resin, and has a wiring pattern made of a material such as copper formed thereon. The substrate may be a single-layer substrate with only one layer of wiring pattern formed thereon, or a multi-layer substrate with multiple layers of wiring pattern formed thereon. In FIG. 2, components corresponding to those shown in FIG. 1 are denoted by the same reference numerals.

[0034] 2, the substrate SB is provided with an area R1 where the control unit 10a is provided and an area R2 where the control unit 10b is provided. A slit SL (an area where no wiring pattern is formed) is formed between the area R1 and the area R2, ensuring insulation between the area R1 and the area R2.

[0035] Area R1 of the substrate SB is equipped with a power supply circuit 11a, a microcomputer 13a, a motor driver 14a, a motor drive circuit 15a, and a step-down circuit 16. The power supply circuit 11a, the microcomputer 13a, the motor driver 14a, and the step-down circuit 16 are implemented as IC chips. In contrast, the motor drive circuit 15a is equipped with six switching elements that constitute an inverter (a pair of switching elements Q11 corresponding to the U phase, a pair of switching elements Q12 corresponding to the V phase, and a pair of switching elements Q13 corresponding to the W phase). Note that an IC chip or the like that implements the interface circuit 12a may be added to area R1 of the substrate SB in accordance with the interface specifications.

[0036] Area R2 of the substrate SB is equipped with a power supply circuit 11b, a microcomputer 13b, a motor driver 14b, and a motor drive circuit 15b. The power supply circuit 11b, the microcomputer 13b, and the motor driver 14b are implemented as IC chips. In contrast, the motor drive circuit 15b is equipped with six switching elements that constitute an inverter (a pair of switching elements Q21 corresponding to the U phase, a pair of switching elements Q22 corresponding to the V phase, and a pair of switching elements Q23 corresponding to the W phase). Note that an IC chip or a filter that implements the interface circuit 12b may be added to area R2 of the substrate SB in accordance with the interface specifications.

[0037] Furthermore, an inter-system communication circuit 20 is mounted on the substrate SB between the microcomputer 13a and the microcomputer 13b, spanning the slit SL. This inter-system communication circuit 20 is implemented as an IC chip. The inter-system communication circuit 20 is connected to the microcomputer 13a via a wiring pattern (not shown) formed in an area R1 of the substrate SB, and is connected to the microcomputer 13b via a wiring pattern (not shown) formed in an area R2 of the substrate SB.

[0038] Through holes A11 and A12 are formed at one end of the substrate SB in region R1, and through holes A21 and A22 are formed at one end of the substrate SB in region R2. The through holes A11 and A12 are through holes into which a pair of lead wires connected to the positive and negative electrodes of an external power supply PS1 are inserted, and the through holes A21 and A22 are through holes into which a pair of lead wires connected to the positive and negative electrodes of an external power supply PS2 are inserted. By inserting the pair of lead wires connected to the positive and negative electrodes of the external power supply PS1 into the through holes A11 and A12, power is supplied from the external power supply PS1 to the control unit 10a. Similarly, by inserting the pair of lead wires connected to the positive and negative electrodes of the external power supply PS2 into the through holes A21 and A22, power is supplied from the external power supply PS2 to the control unit 10b.

[0039] Through holes B11, B12, and B13 are formed near the other end of the substrate SB in region R1, and through holes B21, B22, and B23 are formed near the other end of the substrate SB in region R2. The through holes B11, B12, and B13 are through holes into which lead wires connected to the U-phase winding, V-phase winding, and W-phase winding of the motor M1 are respectively inserted. The through holes B21, B22, and B23 are through holes into which lead wires connected to the U-phase winding, V-phase winding, and W-phase winding of the motor M2 are respectively inserted.

[0040] Next, the operation of the motor control device 1 configured as described above will be described. For example, when a vehicle driver operates the ignition key, an ignition signal is input to the control units 10a and 10b via the external interfaces IF1 and IF2, respectively. The ignition signals input to the control units 10a and 10b are input to the microcomputers 13a and 13b via the interface circuits 12a and 12b, respectively. Then, the microcomputers 13a and 13b start controlling the motors M1 and M2.

[0041] In the control unit 10a, the output voltage (e.g., 48 [V]) of the external power supply PS1 is stepped down to a predetermined voltage (e.g., 12 [V]) by the step-down circuit 16, and the stepped-down voltage is applied to the power supply circuit 11a, the motor driver 14a, and the motor drive circuit 15a. In addition, in the power supply circuit 11a, a voltage (e.g., 5 [V]) referenced to the ground G1 is generated from the applied voltage (the voltage stepped down by the step-down circuit 16) and applied to the microcomputer 13a and the motor driver 14a.

[0042] The voltage stepped down by the step-down circuit 16 may differ slightly from the output voltage of the external power supply PS2. However, since the difference between the voltage stepped down by the step-down circuit 16 and the output voltage of the external power supply PS2 is slight, this does not pose a problem for the control units 10a and 10b in controlling the motors M1 and M2.

[0043] Similarly, in the control unit 10a, the output voltage (e.g., 12 [V]) of the external power supply PS2 is applied to the power supply circuit 11b, the motor driver 14b, and the motor drive circuit 15b. In addition, in the power supply circuit 11b, a voltage (e.g., 5 [V]) referenced to the ground G2 is generated from the applied voltage (the output voltage of the external power supply PS2) and applied to the microcomputer 13b and the motor driver 14b.

[0044] When a driver of a vehicle turns the steering wheel, the steering torque is detected by a torque sensor (not shown). A torque sensor signal indicating the detected steering torque is input to control units 10a and 10b via external interfaces IF1 and IF2, respectively. The torque sensor signals input to control units 10a and 10b are input to microcomputers 13a and 13b via interface circuits 12a and 12b, respectively.

[0045] When the torque sensor signal is input, the microcomputers 13a and 13b calculate the required torque using the input torque sensor signal and CAN signals indicating vehicle conditions such as vehicle speed and engine RPM, and output the motor control amount to the motor drivers 14a and 14b, respectively. The motor drivers 14a and 14b generate drive signals corresponding to the motor control amount output from the microcomputers 13a and 13b, and output the drive signals to the motor drive circuits 15a and 15b, respectively. The motor drive circuits 15a and 15b drive the motors M1 and M2 based on the drive signals output from the motor drivers 14a and 14b, respectively. In this way, a steering assist torque for steering is generated.

[0046] As described above, in this embodiment, of the control units 10a and 10b that are connected to external power supplies PS1 and PS2, respectively, and that control the motors M1 and M2 that share an output shaft, the control unit 10a is provided with the step-down circuit 16. The output voltage of the external power supply PS1 is stepped down to the same voltage as the output voltage of the external power supply PS2. This makes it possible to improve torque ripple or NV performance even when different voltages are supplied to the first system SY1 that controls the motor M1 and the second system SY2 that controls the motor M2.

[0047] Second Embodiment FIG. 3 is a block diagram showing the configuration of a main part of a motor control device according to a second embodiment of the present disclosure. Note that in FIG. 3, blocks similar to those shown in FIG. 1 are assigned the same reference numerals. As shown in FIG. 3, motor control device 2 of this embodiment is configured by adding a voltage monitor circuit 17 to control unit 10b of motor control device 1 shown in FIG. 1 and providing a microcomputer 13B instead of microcomputer 13b. In this motor control device 2, a motor output adjustment function is added to second system SY2, which adjusts the output of motor M2 in accordance with the output voltage of external power supply PS2.

[0048] The voltage monitor circuit 17 monitors the output voltage of the external power supply PS2. The voltage monitor circuit 17 outputs the monitored voltage to the microcomputer 13B. The microcomputer 13B is the microcomputer 13b shown in FIG. 1 with the motor output adjustment function described above added. Like the microcomputer 13b, the microcomputer 13B calculates the required torque using the torque sensor signal output from the interface circuit 12b and the CAN signal indicating the vehicle state such as the vehicle speed and engine RPM, and outputs the motor control amount to the motor driver 14b.

[0049] However, microcomputer 13B adjusts the output of motor M2 according to the voltage monitored by voltage monitor circuit 17. Specifically, when the voltage monitored by voltage monitor circuit 17 differs from the voltage (e.g., 12 V) stepped down by step-down circuit 16 of control unit 10a, microcomputer 13B adjusts the motor output of motor M2 so that the output of motor M2 becomes the same as the output of motor M1.

[0050] For example, when the voltage monitored by voltage monitor circuit 17 is higher than the voltage stepped down by step-down circuit 16 of control unit 10a, microcomputer 13B outputs to motor driver 14b a motor control amount that is reduced by an amount corresponding to the voltage difference, thereby adjusting the motor output of motor M2. On the other hand, when the voltage monitored by voltage monitor circuit 17 is lower than the voltage stepped down by step-down circuit 16 of control unit 10a, microcomputer 13B outputs to motor driver 14b a motor control amount that is increased by an amount corresponding to the voltage difference, thereby adjusting the motor output of motor M2.

[0051] FIG. 4 is a plan view of a substrate illustrating an example implementation of a motor control device according to a second embodiment of the present disclosure. Note that in FIG. 4, blocks similar to those shown in FIGS. 2 and 3 are assigned the same reference numerals. As shown in FIG. 4, in the motor control device 2 of this embodiment, a voltage monitor circuit 17 is added to region R2 of the substrate SB shown in FIG. 2, and a microcomputer 13B is provided in place of the microcomputer 13b. The voltage monitor circuit 17 and the microcomputer 13B are implemented as IC chips.

[0052] The operation of the motor control device 2 is basically the same as the operation of the motor control device 1 of embodiment 1, except that the output of the motor M2 is adjusted according to the voltage monitored by the voltage monitor circuit 17. Therefore, a detailed description thereof will be omitted here.

[0053] As described above, in this embodiment, as in the first embodiment, of the control units 10a and 10b that are connected to external power supplies PS1 and PS2, respectively, and that control the motors M1 and M2 that share an output shaft, the control unit 10a is provided with the step-down circuit 16. The output voltage of the external power supply PS1 is stepped down to the same voltage as the output voltage of the external power supply PS2. This makes it possible to improve torque ripple or NV performance even when different voltages are supplied to the first system SY1 that controls the motor M1 and the second system SY2 that controls the motor M2.

[0054] Additionally, in this embodiment, the control unit 10b is provided with a voltage monitor circuit 17 that monitors the output voltage of the external power supply PS2, and the output of the motor M2 is adjusted according to the voltage monitored by the voltage monitor circuit 17. This makes it possible to improve the torque ripple or NV performance more than in the first embodiment.

[0055] Third Embodiment Figure 5 is a block diagram showing the configuration of a main part of a motor control device according to a third embodiment of the present disclosure. Note that in Figure 5, blocks similar to those shown in Figure 3 are assigned the same reference numerals. As shown in Figure 5, motor control device 3 of this embodiment is configured by adding an inter-system communication circuit 21 (communication circuit) to motor control device 2 shown in Figure 3 and providing a step-down circuit 16A instead of step-down circuit 16. This motor control device 3 adds a feedback function that feeds back the monitored output voltage of external power supply PS2 to first system SY1.

[0056] The inter-system communication circuit 21 is a circuit that transmits the voltage monitored by the voltage monitor circuit 17 to the step-down circuit 16A of the control unit 10a. The step-down circuit 16A steps down the output voltage of the external power supply PS1 to the same voltage as the voltage transmitted from the inter-system communication circuit 21. The above-mentioned feedback function is realized by the inter-system communication circuit 21 and the step-down circuit 16A.

[0057] FIG. 6 is a plan view of a substrate illustrating an example implementation of a motor control device according to a third embodiment of the present disclosure. Note that in FIG. 6, blocks similar to those shown in FIGS. 4 and 5 are assigned the same reference numerals. As shown in FIG. 6, in the motor control device 3 according to this embodiment, an inter-system communication circuit 21 is mounted across the slit SL, and a step-down circuit 16A is provided instead of the step-down circuit 16. The inter-system communication circuit 21 and the step-down circuit 16A are implemented as IC chips. Note that the inter-system communication circuit 21 is connected to the step-down circuit 16A via a wiring pattern (not shown) formed in region R1 of the substrate SB, and is connected to the voltage monitor circuit 17 via a wiring pattern (not shown) formed in region R2 of the substrate SB.

[0058] The operation of the motor control device 3 is basically the same as the operation of the motor control device 1 of the first embodiment, except that the output voltage of the external power supply PS1 is stepped down by the step-down circuit 16A to the same voltage as the voltage monitored by the voltage monitor circuit 17. Therefore, a detailed description thereof will be omitted here.

[0059] As described above, in this embodiment, as in the first embodiment, of the control units 10a and 10b that are connected to external power supplies PS1 and PS2, respectively, and that control the motors M1 and M2 that share an output shaft, the control unit 10a is provided with the step-down circuit 16. The output voltage of the external power supply PS1 is stepped down to the same voltage as the output voltage of the external power supply PS2. This makes it possible to improve torque ripple or NV performance even when different voltages are supplied to the first system SY1 that controls the motor M1 and the second system SY2 that controls the motor M2.

[0060] Also, in this embodiment, as in the second embodiment, the control unit 10b is provided with a voltage monitor circuit 17 that monitors the output voltage of the external power supply PS2, and the output of the motor M2 is adjusted according to the voltage monitored by the voltage monitor circuit 17. This makes it possible to improve the torque ripple or NV performance more than in the first embodiment.

[0061] Furthermore, in this embodiment, an inter-system communication circuit 21 is provided that transmits the voltage monitored by the voltage monitor circuit 17 to the step-down circuit 16A, so that the output voltage of the external power supply PS1 is stepped down to the same voltage as the voltage monitored by the voltage monitor circuit 17. This makes it possible to match the voltage used by the control unit 10a and the voltage used by the control unit 10b, thereby improving the torque ripple or NV performance more than in the second embodiment.

[0062] The voltage monitored by the voltage monitor circuit 17 is output to the microcomputer 13B, and the microcomputer 13B can communicate with the microcomputer 13a via the inter-system communication circuit 20. Therefore, the voltage monitored by the voltage monitor circuit 17 may be transmitted to the step-down circuit 16A via a path that passes through the microcomputer 13B, the inter-system communication circuit 20, and the microcomputer 13a. When the voltage monitored by the voltage monitor circuit 17 is transmitted via this path, the inter-system communication circuit 21 may be omitted.

[0063] Fourth Embodiment FIG. 7 is a block diagram showing the configuration of a main part of a motor control device according to a fourth embodiment of the present disclosure. In FIG. 7, blocks that are the same as those shown in FIG. 1 are assigned the same reference numerals. As shown in FIG. 7, motor control device 4 of this embodiment has a configuration in which step-down circuit 16 of motor control device 1 shown in FIG. 1 is replaced with step-up circuit 18. Such motor control device 4 is able to handle cases in which the magnitude relationship of the output voltages of external power supplies PS1 and PS2 is reversed.

[0064] In the first embodiment, the output voltage of external power supply PS1 is higher than the output voltage of external power supply PS2. In contrast, in the present embodiment, the output voltage of external power supply PS1 is lower than the output voltage of external power supply PS2. For example, external power supply PS1 is a DC power supply with an output voltage of 12 V, and external power supply PS2 is a DC power supply with an output voltage of 48 V.

[0065] The boost circuit 18 is connected to the external power supply PS1 and boosts the output voltage (first voltage) of the external power supply PS1 to a predetermined voltage. For example, the boost circuit 18 boosts the output voltage (12 V) of the external power supply PS1 to the same voltage (48 V) as the output voltage of the external power supply PS2.

[0066] The operation of motor control device 4 of this embodiment is basically the same as the operation of motor control device 1 of embodiment 1, except that the output voltage of external power supply PS1 is boosted. Therefore, a detailed description will be omitted here. Note that this embodiment differs from embodiment 1 in the magnitude of the voltages applied to power supply circuits 11a and 11b, motor drivers 14a and 14b, and motor drive circuits 15a and 15b.

[0067] Motor control device 4 of the present embodiment can also handle cases where the magnitude relationship between the output voltage of external power supply PS1 and the output voltage of external power supply PS2 is reversed in embodiment 1. In other words, it can handle cases where the output voltage of external power supply PS1 is lower than the output voltage of external power supply PS2.

[0068] This embodiment can also be applied to embodiments 2 and 3. Specifically, a boost circuit 18 may be provided in place of the step-down circuit 16 shown in FIGS. 3 and 4 or the step-down circuit 16A shown in FIGS.

[0069] Fifth Embodiment FIG. 8 is a block diagram showing the configuration of a main part of a motor control device according to a fifth embodiment of the present disclosure. Note that in FIG. 8, blocks that are the same as those shown in FIG. 1 are assigned the same reference numerals. As shown in FIG. 8, motor control device 5 of this embodiment has a configuration in which step-down circuit 16 of motor control device 1 shown in FIG. 1 is replaced with a step-up / step-down circuit 19. Such motor control device 5 is able to handle cases where the output voltage of external power supply PS1 is not fixed but the output voltage of external power supply PS2 is fixed.

[0070] In the first embodiment, the output voltage of external power supply PS1 is higher than the output voltage of external power supply PS2. In contrast, in the present embodiment, the output voltage of external power supply PS1 is not fixed, but the output voltage of external power supply PS2 is fixed. For example, external power supply PS1 is a DC power supply whose output voltage can range from 12 to 60 V, and external power supply PS2 is a DC power supply whose output voltage is 48 V.

[0071] The step-up / step-down circuit 19 is connected to the external power supply PS1 and steps up or down the output voltage (first voltage) of the external power supply PS1 to a predetermined voltage. Specifically, when the output voltage of the external power supply PS1 is higher than the output voltage of the external power supply PS2, the step-up / step-down circuit 19 steps down the output voltage of the external power supply PS1 to the predetermined voltage. On the other hand, when the output voltage of the external power supply PS1 is lower than the output voltage of the external power supply PS2, the step-up / step-down circuit 19 steps up the output voltage of the external power supply PS1 to the predetermined voltage.

[0072] For example, if the output voltage of external power supply PS1 is 60 V, the step-up / step-down circuit 19 steps down the output voltage of external power supply PS1 to the same voltage (48 V) as the output voltage of external power supply PS2. On the other hand, if the output voltage of external power supply PS1 is 12 V, the step-up / step-down circuit 19 steps up the output voltage of external power supply PS1 to the same voltage (48 V) as the output voltage of external power supply PS2.

[0073] The operation of motor control device 5 of the present embodiment is basically the same as the operation of motor control device 1 of embodiment 1, except that the output voltage of external power supply PS1 is increased or decreased. Therefore, a detailed description will be omitted here. Note that, as with embodiment 4, this embodiment differs from embodiment 1 in the magnitude of the voltages applied to power supply circuits 11a and 11b, motor drivers 14a and 14b, and motor drive circuits 15a and 15b.

[0074] Motor control device 5 of the present embodiment can also accommodate a case in which the output voltage of external power supply PS1 in embodiment 1 is not fixed, but the output voltage of external power supply PS2 is fixed. In other words, it can accommodate both a case in which the output voltage of external power supply PS1 is lower or higher than the output voltage of external power supply PS2.

[0075] This embodiment can also be applied to embodiments 2 and 3. Specifically, a step-up / step-down circuit 19 may be provided in place of the step-down circuit 16 shown in FIGS. 3 and 4 or the step-down circuit 16A shown in FIGS.

[0076] Although the embodiments have been described above, the present disclosure is not limited to the above embodiments and can be freely modified without departing from the spirit of the present disclosure. For example, in the above-described first to third embodiments, the output voltage of the external power supply PS1 is 48 [V] and the output voltage of the external power supply PS2 is 12 [V]. However, the output voltages of the external power supplies PS1 and PS2 are not limited to 48 [V] and 12 [V], and may be any voltage. Furthermore, as described in the fourth embodiment, the magnitude relationship between the output voltages of the external power supplies PS1 and PS2 may be reversed. Alternatively, as described in the fifth embodiment, the output voltage of the external power supply PS1 may be indefinite and the output voltage of the external power supply PS2 may be fixed.

[0077] In the above-described embodiment, an example has been described in which the motor control device performs CAN communication via external interfaces IF1 and IF2 to receive CAN signals indicating vehicle conditions such as vehicle speed and engine RPM. However, the communication performed by the motor control device may be other communication methods such as Flex-ray communication in addition to CAN communication.

[0078] In the above-described embodiment, the inter-system communication circuits 20, 21 and the voltage monitor circuit 17 are implemented as IC chips. However, the inter-system communication circuits 20, 21 or the voltage monitor circuit 17 may be implemented using discrete components.

[0079] Each component of the motor control device described above has an internal computer system. A program for implementing the functions of each component of the motor control device described above may be recorded on a computer-readable recording medium, and the program recorded on the recording medium may be read into a computer system and executed to perform processing in each component of the motor control device described above. Here, "reading a program recorded on a recording medium into a computer system and executing it" includes installing the program into a computer system. The term "computer system" here includes the OS and hardware such as peripheral devices.

[0080] Furthermore, a "computer system" may include multiple computer devices connected via a network, including the Internet or communication lines such as a WAN, LAN, or dedicated line. Furthermore, a "computer-readable recording medium" refers to portable media such as flexible disks, optical magnetic disks, ROMs, and CD-ROMs, as well as storage devices such as hard disks built into a computer system. Thus, the recording medium storing the program may be a non-transitory recording medium such as a CD-ROM.

[0081] The recording medium also includes internal or external recording media accessible from a distribution server for distributing the program. The program may be divided into multiple parts, downloaded at different times, and then combined by the various components of the motor control device. Each divided program may be distributed by a different distribution server. Furthermore, the term "computer-readable recording medium" also includes a medium that stores a program for a certain period of time, such as volatile memory (RAM) within a computer system that serves as a server or client when a program is transmitted over a network. The program may also be a medium for implementing part of the above-described functions. Furthermore, the program may be a so-called differential file (differential program) that can realize the above-described functions in combination with a program already stored in the computer system. [Explanation of symbols]

[0082] 1 to 3... Motor control device, 10a, 10b... Control unit, 16, 16A... Step-down circuit, 17... Voltage monitor circuit, 18... Step-up circuit, 19... Step-up / step-down circuit, 21... Inter-system communication circuit, G1, G2... Ground, M1, M2... Motor, PS1, PS2... External power supply

Claims

1. A motor control device that controls a first motor and a second motor that share an output shaft, a first control unit including a voltage conversion circuit that converts a first voltage output from a first power supply into a predetermined voltage, and that controls the first motor using the predetermined voltage converted by the voltage conversion circuit; a second control unit that controls the second motor using a second voltage output from a second power supply; Equipped with the second control unit includes a voltage monitor circuit that monitors the second voltage output from the second power supply, and adjusts the motor output of the second motor in accordance with the voltage value monitored by the voltage monitor circuit so that the motor output of the second motor becomes the same as the motor output of the first motor. Motor control device.

2. The motor control device according to claim 1 , wherein the voltage conversion circuit converts the first voltage to the same voltage as the second voltage.

3. 2. The motor control device according to claim 1, wherein the second control unit adjusts the motor output of the second motor so that the motor output of the second motor becomes the same as the motor output of the first motor when the voltage value monitored by the voltage monitor circuit differs from the predetermined voltage.

4. the voltage conversion circuit adjusts the predetermined voltage to a voltage value monitored by the voltage monitor circuit; The motor control device according to claim 1 .

5. 5. The motor control device according to claim 4, further comprising a communication circuit provided between the first control unit and the second control unit, the communication circuit transmitting the voltage value monitored by the voltage monitor circuit to the voltage conversion circuit.

6. the second voltage output from the second power supply is lower than the first voltage output from the first power supply, the voltage conversion circuit is a step-down circuit that steps down the first voltage output from the first power supply to the same voltage as the second voltage; The motor control device according to claim 1 .

7. the second voltage output from the second power supply is higher than the first voltage output from the first power supply, the voltage conversion circuit is a boost circuit that boosts the first voltage output from the first power supply to the same voltage as the second voltage; The motor control device according to claim 1 .

8. the voltage conversion circuit is a step-up / step-down circuit that, when the first voltage output from the first power supply is higher than the second voltage output from the second power supply, steps down the first voltage output from the first power supply to the same voltage as the second voltage, and, when the first voltage is lower than the second voltage output from the second power supply, steps up the first voltage output from the first power supply to the same voltage as the second voltage. The motor control device according to claim 1 .

9. The motor control device according to claim 1 , wherein the first control unit and the second control unit are provided with grounds that are separated from each other.

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