Motor control device and motor control method

Abstract

The present invention suppresses rotational vibration when a locked state of a parking lock system is released and reduces wear on a meshing part of the parking lock system. Provided is a motor control device (80) that controls a drive motor (10) of an electric vehicle which is provided with a parking lock system (2) for keeping a wheel (35a, 35b) in a non-rotatable state when parked. The motor control device (80) detects the release of a locked state of the parking lock system (2), and, on the basis of the rotational speed of the drive motor (10), forms an active damping torque in the direction opposite to the direction of rotational vibration of the drive motor (10).

Description

[0001] [Document name] Statement

[0002] [Title of Invention] Motor control device and motor control method

[0003] [Technical Field]

[0004]

[001] The present invention relates to a motor control device and a motor control method.

[0005] [Background technology]

[0006] [. 0 0 2] A parking lock system is known that keeps the wheels from rotating when the vehicle is parked. ○ A park lock system is provided in the drive system of an electric vehicle and locks the rotating elements of the drive system to prevent the wheels from rotating when the vehicle is parked. For example, Patent Document 1 discloses a parking lock system that includes a parking rod, a parking lever, and a parking gear, where the parking lever is arranged to be swingable around its shaft by an actuator, and the parking gear side of the parking lever is provided with a convex portion that can mesh with the parking gear, and the system can be switched between a state in which the convex portion and the parking gear are meshed and a state in which the meshing is released. The parking gear is connected to the drive shaft and arranged to be able to mesh with the convex portion of the parking lever, and when the parking gear and the convex portion mesh with each other, rotation of the drive shaft is restricted. ○

[0007]

[0003] In the parking lock system described in Patent Document 1, when the shift range is switched from parking range (P range) to a range other than P range (not P range) and from not P range to P range, an actuator is driven to engage or disengage the parking gear and the convex portion of the parking lever. Regardless of the shift range, the parking lock system may also be used to ensure safety when a vehicle malfunction occurs or the ignition switch is turned off. For example, if a malfunction of a specific component in the vehicle system is detected or if an off signal is detected from the ignition switch, the park lock system will engage the parking gear and the convex portion of the parking lever to restrict wheel rotation. If the drive shaft is rotating at high speed at this time, there is a risk of damage to the components of the parking lock system. In response to this, Patent Document 2 proposes a parking lock system that allows the parking gear and the protrusion of the parking lever to engage when the vehicle speed or acceleration is below a predetermined value.

[0008] [Prior art documents]

[0009] [Patent documents]

[0010]

〇 0 0 4

[0011] [Patent Document 1] Japanese Patent Application Laid-Open No. 2023-159723

[0012] [Patent Document 2] German Patent Application Publication No. 102020211436

[0013] Summary of the Invention

[0014] [Problem to be solved by the invention]

[0015] [0 0 5] When a vehicle is parked on a slope, the vehicle's weight generates a rotational torque that tries to rotate the wheels, elastically deforming the drive shaft connected to the wheels and inducing a rotational torque in the parking gear. The greater the inclination angle of the road, the greater the rotational torque induced in the parking gear. If the parking lock system is unlocked in this state, the rotational torque applied to the parking gear is released. In the case of an electric vehicle, the release of the rotational torque of the drive shaft causes rotational vibration (swing) in the rotor and drive shaft of the drive motor. This may cause wear at the meshing portion between the parking gear and parking lever of the park lock system.

[0016]

[0006] The present invention has been made in consideration of the above problems, and provides a motor control device and a motor control method that can suppress rotational vibration when the locked state of the park lock system is released and reduce wear on the engaging parts of the park lock system. [Means for solving the problem]

[0017]

[0007] In order to solve the above problem, according to one aspect of the present invention, there is provided a motor control device for controlling a drive motor of an electric vehicle equipped with a parking lock system that keeps the wheels in a non-rotatable state when parking, the motor control device detecting that the locked state of the parking lock system is released, and generating an active damping torque in a direction opposite to the direction of rotational vibration of the drive motor based on the rotational speed of the drive motor.

[0018]

[0008] In order to solve the above problem, according to another aspect of the present invention, there is provided a motor control method for controlling a drive motor of an electric vehicle equipped with a parking lock system that keeps the wheels in a state where they cannot rotate when parking, the motor control method performing the steps of: detecting that the locked state of the parking lock system is released; and generating an active damping torque in a direction opposite to the direction of rotational vibration of the drive motor based on the rotational speed of the drive motor.

[0019] [Effects of the Invention]

[0020]

[0009] As described above, according to the present invention, it is possible to suppress rotational vibration when the park lock system is released from its locked state, and reduce wear on the engaging parts of the park lock system.

[0021] BRIEF DESCRIPTION OF THE DRAWINGS

[0022] [ 0 0 1 0 ]

[0023] [Figure 1] An explanatory diagram showing an example configuration of a parking lock system according to an embodiment of the present invention.

[0024] [Figure 2] An explanatory diagram showing the disengaged state and engaged state of the park lever and lock wheel of the parking lock system according to the same embodiment.

[0025] [Fig. 3] An explanatory diagram showing rotational vibration and impact that may occur when the park lock system is released from its locked state.

[0026] [Figure 4] An explanatory diagram showing a reference example of rotational vibration that may occur when the park lock system is released from its locked state.

[0027] [Figure 5] A block diagram showing an example configuration of a motor control device according to the same embodiment.

[0028] [Figure 6] A flowchart showing the motor control method according to the same embodiment.

[0029] [Figure 7] An explanatory diagram showing the operation of the motor control method according to the embodiment.

[0030] [Mode for Carrying Out the Invention]

[0031]

[0011] Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings. In this specification and drawings, components having substantially the same functional configurations are designated by the same reference numerals, and redundant explanations will be omitted.

[0032] [ 0 0 1 2 ]

[0033] <1. Drive system for electric vehicle> First, an example configuration of a drive system for an electric vehicle to which a motor control device according to an embodiment of the present invention can be applied will be described. Fig. 1 is a schematic diagram showing an example configuration of a drive system 1 for an electric vehicle. The drive system 1 is a drive system that uses a drive motor 10 as a drive power source, and includes a drive motor 10, a transmission 20, and a park lock system 2.

[0034]

[0013] The drive motor 10 is a permanent magnet three-phase AC motor equipped with a rotor 13 mounted on a motor shaft 15 that outputs rotational torque, and a stator 11 arranged on the outer periphery of the rotor 13. The drive motor 10 is driven by three-phase AC power supplied from an inverter 19. The inverter 19 is controlled by a motor control device 80, and converts DC power output from a battery 70 into three-phase AC power and outputs it. The drive motor 10 is equipped with a rotation speed sensor 17 that measures the rotation speed of the motor shaft 15. The rotation speed sensor 17 may be, for example, a resolver, but is not limited to a resolver.

[0035]

[0014] The motor control device 80 is configured with a microcomputer and peripheral components, and controls the drive of the inverter 19. The motor control device 80 is configured to be able to acquire a sensor signal from the rotation speed sensor 17. In addition, the motor control device 80 is connected to the park lock control device 50 so as to be able to communicate with it.

[0036]

[0015] The transmission 20 includes a gear mechanism that transmits rotational torque output via the motor shaft 15, and a differential gear 31 that distributes the rotational torque to left and right wheels 35a, 35b. The gear mechanism includes a drive gear 21 that is fixed to the motor shaft 15 and rotates in synchronization with the motor shaft 15, a driven gear 23 that is fixed to the intermediate shaft 25 and meshes with the drive gear 21 and rotates in synchronization with the intermediate shaft 25, and a ring gear 29 that is fixed to the intermediate shaft 25 and meshes with the ring gear 29 of the differential gear 31 and rotates in synchronization with the intermediate shaft 25.

[0037] 25 and an output gear 27 that rotates in synchronization with the output gear 25.

[0038]

[0016] The park lock system 2 holds the wheels 35a, 35b in a non-rotatable state when parking. The park lock system 2 distributes the drive torque output from the drive motor 1 to the left and right wheels.

[0039] The vehicle is equipped with a locking mechanism 40 attached to the transmission 20 that transmits power to the axles 33a and 33b connected to the axles 35a and 35b, and a parking lock control device 50 that controls the operation of the locking mechanism 40.

[0040]

[0017] The lock mechanism 40 comprises a lock wheel 41, a park lever 43 and an actuator 45. The lock wheel 41 has at least one engagement portion on its outer circumferential surface, is fixed concentrically to the motor shaft 15 and rotates synchronously with the motor shaft 15. The lock wheel 41 may be fixed to a rotating shaft provided in a driving force transmission path that transmits the rotational torque of the drive motor 10 to the wheels 35a, 35b, such as the intermediate shaft 25. The park lever 43 has a locking portion that can engage with the engagement portion of the lock wheel 41 and is supported displaceably so that the locking portion can be switched between engagement and disengagement with the engagement portion. The actuator 45 is

[0041] The actuator 45 is equipped with a component, such as an electric motor, that is driven by controlling the supply of power, and is capable of displacing the park lever 43.

[0042]

[0018] The park lock control device 50 is configured with a microcomputer and peripheral components, and controls the operation of the actuator 45 of the lock clock system 2.

[0043] The park lock control device 50 is configured to be able to acquire a sensor signal from the rotation speed sensor 17. The park lock control device 50 is also configured to be able to acquire a sensor signal from the shift position sensor 3 that detects the position of the shift range selected by the driver operating the shift lever or shift switch. Furthermore, the park lock control device 50 is connected to the motor control device 80 so that it can communicate with them.

[0044] [ 0 0 1 9 ]

[0045] <2. Locking mechanism> Next, we will explain in detail the locking mechanism 40 of the Park Lock System 2.

[0046]

[0020] Fig. 2 is a schematic diagram showing the operating state of the locking mechanism 40. In this specification, the state in which the rotation of the motor shaft 15 is restricted is referred to as the "locked state." Furthermore, the state in which the restriction on the rotation of the motor shaft 15 is released is referred to as the "unlocked state."

[0047]

[0021] The illustrated lock mechanism 40 includes a lock wheel 41, a park lever 43, a cam 46, and an actuator 45. The lock wheel 41 has at least one engagement portion 42 on its outer circumferential surface. The lock wheel 41 is fixed concentrically to the motor shaft 15. The lock wheel 41 has a locking claw 43 which can enter and engage with an engagement portion 42 of the lock wheel 41. The park lever 43 is supported so as to be swingable about a rotation shaft 43a and is fixed to a rotation shaft 47 which is rotationally driven by an actuator 45. The actuator 45 rotates the rotation shaft 47, causing the park lever 43 to move. A cam 46 moves the park lever 43 toward the lock wheel 41, and the locking claw 44 of the lever 43 enters the engagement portion 42 of the lock wheel 41, restricting motor rotation. On the other hand, when the cam 46 moves in a direction away from the park lever 43, the locking claw 44 of the park lever 43 disengages from the engagement portion 42 of the lock wheel 41. When the shift range is in the parking range (P), the locking claw 44 of the park lever 43 enters the engagement portion 42 of the lock wheel 42 and is in a locked state. On the other hand, when the shift range is in the park range (nP), the locking claw 44 of the park lever 43 disengages from the lock wheel 42 and is in an unlocked state. The control device 50 acquires a sensor signal from a shift position sensor that detects the position of the shift range selected when the driver operates the shift lever or shift switch, and determines the shift range. In addition, the park lock control device 50 determines the rotation speed of the drive motor 10 based on the sensor signal from the rotation speed sensor 17, and when the shift range is in the parking range, the park lock control device 50 enters a locked state and restricts the rotation of the motor shaft 15, and the wheels 35a, 35b do not rotate. In addition, the park lock control device 50 When the shift range is in the parking range, the locking mechanism 40 is released from its locked state, allowing the motor shaft 15 to rotate, and the motor shaft 35b to rotate.Mechanism Wear When a vehicle is parked on a slope and tilted forward or backward, the park lever 43 disengages from the engagement portion 42 of the lock wheel 41, unlocking the vehicle. The rotational torque acting to rotate the wheels 35a, 35b due to the load of both wheels is transmitted to the lock wheel 41 via the gear mechanism of the transmission 20 and the park lever 43. The rotational torque applied to the lock wheel 41 is released when the park lever 43 disengages from the engagement portion 42 of the lock wheel 41, causing rotational vibration in the rotor 13 of the motor shaft 1. The rotational movement of the cam 46 also causes the park lever 43 to swing. The swinging of the lever 43 and the rotational vibration of the lock wheel 41 induce an impact at the engagement portion between the locking pawls 44 and 41. This could cause wear on the contact surface where the park lever 4 and the lock wheel 41 engage, potentially causing the lock mechanism 4 to fail. The figure shows the rotational vibration of the drive motor 10 when the park lever 43 is disengaged from the engagement portion 42 of the lock wheel 41 while a rotational torque is being applied to the lock wheel 41. The example shown in FIG. 4 shows rotational vibration of less than 10 Hz, which indicates that disengagement from the engagement portion 42 generates rotational vibration that subsides over time. The motor control device 80 has a configuration capable of suppressing the above-mentioned rotational vibration. This reduces wear on the locking mechanism 4 of the locking system 2.

[0029]

[0048] <4. Motor control device> Next, the motor control device 8 ○ according to this embodiment will be described.

[0049]

[0030] Figure 5 is a block diagram showing the functional configuration of a motor control device 80. The motor control device 80 includes a processing unit 81 and a memory unit 89. The processing unit 81 includes a microcomputer. The memory unit 89 includes storage media such as RAM (Random Access Memory) and ROM (Read Only Memory). The memory unit 89 stores programs executed by the processing unit 81, various parameters used in calculations, calculation results, detection results, etc. A portion of the memory unit 89 is used as a work area for the processing unit 81.

[0050]

[0031] The processing unit 81 includes a park lock release determination unit 83, a rotation speed determination unit 85, and an active damping control unit 87. Each of these units is realized by, for example, a microcomputer executing a program. However, part of the motor control device 80 may be configured by hardware such as an analog circuit.

[0051]

[0032] The park lock release determination unit 83 determines that the locked state of the park lock system 2 is released and switched to an unlocked state. For example, the park lock release determination unit 83 receives a signal indicating that the locked state is released from the park lock control device 50. The park lock release determination unit 83 may determine that the shift range is switched from the parking range P to a range nP other than the parking range based on a sensor signal from a shift position sensor 3 that detects the position of the shift range selected by the driver operating the shift lever or shift switch.

[0052]

[0033] The rotation speed determination unit 85 determines the rotation speed of the drive motor 10 based on the sensor signal of the rotation speed sensor 17.

[0053]

[0034] When the park lock system 2 switches from a locked state to an unlocked state, the active damping control unit 87 performs active damping control based on the rotational speed of the drive motor 10. For example, the active damping control unit 87 controls the drive of the inverter 19 so that an active damping torque is generated in the opposite direction to the rotational vibration of the drive motor 10.

[0054]

[0035] The active damping control unit 87 may execute active damping control only when a rotational torque is induced in the lock mechanism 40 of the parking lock system 2 while the electric vehicle is stopped. For example, the active damping control unit 87 may calculate the longitudinal tilt angle of the electric vehicle based on a sensor signal from an inclination sensor provided in the electric vehicle, and permit execution of active damping control when the tilt angle is equal to or greater than a predetermined threshold.

[0055] [ 0 0 3 6 ]

[0056] <5. Control Method> Next, a motor control method related to active damping control by the motor control device 8 ○ according to this embodiment will be described in detail.

[0057]

[0037] Fig. 6 is a flowchart showing an example of a motor control method related to active damping control executed by the motor control device 8. First, after the system of the electric vehicle is started, the parking lock release determination unit 83 of the processing unit 81 determines whether or not the locked state of the parking lock system 2 is to be released (step S11). For example, the parking lock release determination unit 83 determines that the locked state of the park lock system 2 is to be released when it receives a signal indicating that the locked state will be released from the park lock control device 50. The park lock release determination unit 83 may also determine that the locked state of the park lock system 2 is to be released when it detects that the shift range has been switched from parking range P to range nP other than the parking range, based on a sensor signal from a shift position sensor 3 that detects the position of the shift range selected by the driver operating the shift lever or shift switch.

[0058]

[0038] If the park lock release determination unit 83 does not determine that the locked state of the park lock system 2 is to be released (S11 / No), it repeats the determination of step S11. On the other hand, if the park lock release determination unit 83 determines that the locked state of the park lock system 2 is to be released (S11 / Yes), the active damping control unit 87 determines whether the longitudinal tilt angle of the electric vehicle calculated based on the sensor signal of the tilt sensor provided in the electric vehicle is equal to or greater than a predetermined minimum value (step S13). The predetermined minimum value may be set to any appropriate value as the angle at which a rotational torque equal to or greater than a predetermined value can be induced in the locking mechanism 40 of the parking lock system 2 while the electric vehicle is stopped.

[0059]

[0039] If the active damping control unit 87 does not determine that the longitudinal tilt angle of the electric vehicle is equal to or greater than the predetermined threshold (S13 / N), it ends the process. On the other hand, if the active damping control unit 87 determines that the longitudinal tilt angle of the electric vehicle is equal to or greater than the predetermined threshold (S13 / Yes), it starts the execution of active damping control (step S15).

[0060]

[0040] Next, the rotational speed determination unit 85 detects the rotational speed of the drive motor 10 based on the sensor signal of the rotational speed sensor 17 (step S17). Next, the active damping control unit 87 calculates an active damping torque to be applied in the opposite direction to the direction of the rotational vibration detected based on the rotational speed of the drive motor 10 (step S19). For example, the active damping control unit 87 calculates a rotational torque equivalent to the magnitude of the amplitude of the rotational vibration as the value of the active damping torque.

[0061]

[0041] Next, the active damping control unit 87 drives the switching elements of the inverter 19 to generate active damping torque (step S21). Next, the active damping control unit 87 determines whether or not a termination condition is met (step S23). For example, the active damping control unit 87 determines whether or not the amplitude of the rotational vibration of the drive motor 10 reaches a predetermined value. 7 shows the rotational vibration of the rotor 13 of the drive motor 10 when active damping control is performed when the locking claw 44 is disengaged from the engagement portion 42 of the lock wheel 41. The example shown in FIG. 7 shows rotational vibration of 10 Hz or less, and although rotational vibration occurs when the locking claw 44 is disengaged from the engagement portion 42, it can be seen that the vibration is damped in a shorter time than in the example shown in FIG.

[0062] [ 0 0 4 4 ]

[0063] <6. Effects> As described above, the motor control device 80 according to this embodiment detects that the locked state of the park lock system 2 is released, and generates an active damping torque in the opposite direction to the direction of the rotational vibration of the drive motor 10 based on the rotational speed of the drive motor 10. As a result, even if the locked state is released with rotational torque induced in the lock wheel 41 while the electric vehicle is stopped, the rotational vibration of the rotor 13 and motor shaft 15 of the drive motor 10 is suppressed, and the impact applied to the meshing portion between the lock wheel 41 of the park lock system 2 and the locking claw 44 of the park lever 43 can be reduced. Therefore, wear on the meshing portion between the lock wheel 41 and the locking claw 44 of the park lever 43 is reduced, and the durability of the park lock system 2 can be improved.

[0064]

[0045] The motor control device 80 according to this embodiment acquires information about the inclination of the road surface and performs active damping control when the inclination of the electric vehicle in the longitudinal direction is equal to or greater than a predetermined threshold. Therefore, when the rotational torque induced in the locked wheel 41 while the electric vehicle is stopped is small and the rotational vibration generated in the rotor 13 and motor shaft 15 of the drive motor 10 when the locked state is released is small, the execution of active damping control is stopped, and the load and power consumption of the motor control device 80 can be reduced.

[0065]

[0046] Although the preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings, the present invention is not limited to such examples. It is clear that a person skilled in the art to which the present invention pertains can conceive of various modifications or alterations within the scope of the technical ideas set forth in the claims, and it is understood that these also naturally fall within the technical scope of the present invention.

[0066] [Explanation of symbols]

[0067] [ 0 0 4 7 ]

[0068] 1: Drive system

[0069] 2:Parking lock system

[0070] 3: Shift position sensor

[0071] 1 〇: Drive motor

[0072] 1 5: Motor shaft

[0073] 1 7: Rotational speed sensor

[0074] 1 9: Inverter

[0075] 2 〇: Transmission

[0076] 4 1: Locking wheel

[0077] 4 2: Engagement part

[0078] 4 3: Park lever

[0079] 4 4: Locking claw

[0080] 4 5 : Actuator

[0081] 4 6: Cam

[0082] 5 〇: Parking lock control device

[0083] 8 〇: Motor control device

[0084] 8 3: Parking lock release determination unit

[0085] 8 5: Rotation speed determination section

[0086] 8 7: Active damping control unit

Claims

[Document name] Scope of claims

1. A motor control device (80) for controlling a drive motor (10) of an electric vehicle equipped with a parking lock system (2) that keeps wheels (35 a, 35 b) in a non-rotatable state when parked, characterized in that the motor control device detects that the locked state of the parking lock system (2) is released, and generates an active damping torque in a direction opposite to the direction of rotational vibration of the drive motor (10) based on the rotational speed of the drive motor (io).

2. The motor control device according to claim 1, wherein information on the inclination of the road surface is acquired, and when the inclination of the electric vehicle in the longitudinal direction is equal to or greater than a predetermined value, control is performed to form the active damping torque.

3. The motor control device according to claim 1, wherein the lock wheel (41) of the parking lock system (2) is provided on the motor shaft (15) of the drive motor (10).

4. A motor control method for controlling a drive motor (io) of an electric vehicle equipped with a parking lock system (2) that keeps wheels (35a, 35b) in a non-rotatable state when parking, the motor control method comprising: detecting that the locked state of the parking lock system (2) is released; and generating an active damping torque in a direction opposite to the direction of rotational vibration of the drive motor (io) based on the rotational speed of the drive motor (io). 8

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