Motor control device

Abstract

To improve controllability of a motor in a simple configuration regarding a motor control device.SOLUTION: A motor control device 10 controls an operation state of a motor so that torsional resonance between the motor and wheels and a power transmission mechanism is restrained. The motor control device 10 comprises: a calculation part 20 which calculates vibration control torque Tff which is input torque to a power transmission mechanism for restraining the torsional resonance on the basis of a transfer function representing vibration characteristics of the power transmission mechanism and request torque of the motor; and a control part 40 which controls the motor on the basis of the vibration control torque Tff. The calculation part 20 has a map 23 on which at least inertia Jload on a load side changing according to a slip state of wheels is regulated, and sets the inertia Jload on the load side related to the transfer function on the basis of the map 23.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] This matter concerns motor control devices for electric vehicles. [Background technology]

[0002] Conventionally, in electric vehicles such as electric cars and hybrid cars that can run on a motor, motor control devices have been developed that can suppress torsional resonance between the motor (drive-side device) and the wheels and power transmission mechanism (load-side device). For example, a technique is known in which the motion state of the drive system is understood using an approximate model of the drive system, and torsional resonance is suppressed by reducing predetermined frequency components included in the control commands (torque commands, driving force commands) for the motor (see Patent Documents 1 and 2). [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2022-058067 [Patent Document 2] Japanese Patent Publication No. 2020-058156 [Overview of the project] [Problems that the invention aims to solve]

[0004] Conventional approximation models for suppressing torsional resonance treat the load-side inertia in the drive system (the moment of inertia on the load side in the power transmission mechanism driven by the drive side (motor)) as a predetermined fixed value. On the other hand, the actual value of the load-side inertia is expected to change depending on the slip state of the drive wheels. Therefore, conventional techniques have difficulty accurately grasping the motion state of the drive system in a slip state, and there is room for improvement in terms of controllability.

[0005] One of the objectives of this invention is to provide a motor control device that improves motor controllability with a simple configuration, devised in light of the above-mentioned problems. However, other objectives of this invention include achieving effects and benefits that cannot be obtained with conventional technology, derived from the various configurations shown in the "Modes for Carrying Out the Invention" section below. [Means for solving the problem]

[0006] The motor control device disclosed can be implemented in the following embodiments (examples of application) and solves at least some of the above-mentioned problems. Each of the embodiments from Embodiment 2 onward is an additional embodiment that can be appropriately selected and each of the embodiments is optional. None of the embodiments from Embodiment 2 onward disclose any embodiments or configurations that are essential to this case.

[0007] Embodiment 1. The motor control device disclosed in an electric vehicle equipped with a motor that drives wheels via a power transmission mechanism controls the operating state of the motor so as torsional resonance between the motor, the wheels, and the power transmission mechanism is suppressed. This motor control device Based on a two-inertia spring-damper system model in the tire linear region. Based on the transfer function representing the vibration characteristics of the power transmission mechanism and the required torque of the motor, By substituting the load-side inertia into the transfer function and filtering out predetermined frequency components of the torque oscillation state, The system includes a calculation unit that calculates a vibration damping torque, which is the input torque to the power transmission mechanism for suppressing the torsional resonance, and a control unit that controls the motor based on the vibration damping torque. Furthermore, the calculation unit changes at least according to the slip state of the wheels. The aforementioned The system has a map that defines the load-side inertia, and sets the load-side inertia related to the transfer function based on that map. Substitute this into the transfer function. do.

[0008] Embodiment 2. In Embodiment 1 described above, it is preferable that the map is a three-dimensional map that defines the relationship between the slip ratio of the wheel, the braking force, and the load-side inertia. Embodiment 3. In Embodiment 2 described above, it is preferable that the slip ratio is calculated based on the vehicle speed and wheel speed of the electric vehicle. The slip ratio can be calculated, for example, by dividing the difference between the wheel speed and the vehicle speed by the vehicle speed.

[0009] Embodiment 4. In Embodiment 3 described above, it is preferable that the wheel speed is a value detected by the wheel speed sensor or a value calculated based on the detected motor angular velocity. In other words, the wheel speed may be an actual measured value (or a calculated value derived from the actual measured value) from the wheel speed sensor, or it may be an estimated value (theoretical value) calculated based on the detected motor angular velocity.

[0010] Embodiment 5. In Embodiment 3 or 4 above, it is preferable that the reference speed of the wheels is calculated based on the vehicle speed and the yaw rate of the electric vehicle, with the effect of turning motion corrected, and that the slip ratio is calculated based on the wheel speed and the reference speed. In other words, it is preferable to use the reference speed as the center of gravity movement speed of each wheel rather than using the vehicle speed as the center of gravity movement speed of the electric vehicle.

[0011] Embodiment 6. In an embodiment including Embodiment 2 described above, it is preferable that the calculation unit sets the load-side inertia based on either the slip ratio of the left and right wheels driven by the motor, or the average value of the respective slip ratios. Embodiment 7. In an embodiment including Embodiment 2 described above, it is preferable that the braking force is calculated based on the maximum value of each braking force in the left and right wheels driven by the motor, or the difference between the left and right braking forces.

[0012] Embodiment 8. In an embodiment including Embodiment 1 described above, it is preferable that the transfer function is a transfer function that represents the relationship between the axle-side torque and the motor-side torque of the power transmission mechanism as shown below.

[0013]

number

[0014] T m : Torque on the motor side of the power transmission mechanism T ds Torque on the axle side of the power transmission mechanism K s : Elastic modulus of power transmission mechanism D s Viscosity coefficient of power transmission mechanism J m Motor Inertia J load Load-side inertia [Effects of the Invention]

[0015] According to the disclosed motor control device, the load-side inertia of the power transmission mechanism, which changes according to the slip state of the wheels, is defined in the map. This allows for accurate understanding of the motion state of the drive system in a slip state, and improves the controllability of the motor with a simple configuration. [Brief explanation of the drawing]

[0016] [Figure 1] This is a block diagram of a vehicle to which the motor control device according to the present invention is applied. [Figure 2] This is a block diagram showing the motor control flow. [Figure 3] This is a schematic diagram showing the relationship between motor torque and motor angular velocity. [Figure 4] (A) is a graph showing the relationship between slip ratio and load-side inertia, and (B) is a graph showing the relationship between braking force and load-side inertia. [Figure 5] (A) is a graph showing the relationship between slip ratio and feedback gain, (B) is a graph showing the relationship between braking force and feedback gain, and (C) is a graph showing the relationship between vehicle speed and correction coefficient. [Modes for carrying out the invention]

[0017] The disclosed motor control device is applicable to electric vehicles (such as electric cars and hybrid vehicles) equipped with motors that drive wheels via a power transmission mechanism. This motor control device has the function of controlling the operating state of the motor so as torsional resonance between the motor (drive-side device) and the wheels and power transmission mechanism (load-side device) is suppressed. The power transmission mechanism here includes, for example, axles connected to the wheels, differentials, reduction gears (gear trains), and transmissions. The number of motors installed in the electric vehicle is irrelevant.

[0018] The disclosed motor control device may be applied to an in-wheel motor vehicle in which each of the left and right wheels is driven independently by a separate motor, or to a torque vectoring vehicle in which each of the left and right wheels can operate in conjunction via a differential mechanism [a torque distribution vehicle in which torque (driving force) input from multiple motors can be distributed between the left and right wheels].

[0019] Furthermore, the electric vehicles to which the disclosed motor control device can be applied include plug-in hybrid electric vehicles (PHEVs) that are capable of external charging or external power supply. A plug-in hybrid vehicle is a hybrid vehicle equipped with an engine and motor as drive sources, a generator as a power generation device, and a battery as an energy storage device, in which the battery can be externally charged or the battery can be externally powered.

[0020] The former plug-in hybrid vehicle is equipped with a charging port (inlet) and a contactless power receiving device for inserting a charging cable that receives power from an external charging facility. The latter plug-in hybrid vehicle is equipped with an outlet and a contactless power supply device for external power supply. It is also possible to install both the above-mentioned charging port and outlet on a single plug-in hybrid vehicle. The disclosed motor control device is applicable to these plug-in hybrid vehicles that are capable of external charging or external power supply. [Examples]

[0021] [1. Equipment configuration] As an embodiment, the motor control device 10 is mounted on the electric vehicle 1 shown in Figure 1. The electric vehicle 1 is equipped with a motor 2 as a drive source that drives the left and right wheels 5 (left and right wheels). The driving force of the motor 2 is transmitted to the left and right wheels 5 via a reduction mechanism 3 and axle 4. The reduction mechanism 3 reduces the rotation output from the motor 2. The reduction mechanism 3 includes a differential device (differential gear) having an open differential mechanism or an LSD (Limited Slip Differential) mechanism.

[0022] Motor 2 is an electric motor that has the function of driving at least the front or rear wheels of the electric vehicle 1, and preferably has both a powering function and a regenerative power generation function. Motor 2 is electrically connected to the battery 7 via an inverter 6. The inverter 6 is a converter (DC-AC inverter) that converts between the power of the DC circuit on the battery 7 side (DC power) and the power of the AC circuit on the motor 2 side (AC power).

[0023] The battery 7 is, for example, a lithium-ion secondary battery or a nickel-metal hydride secondary battery. When the motor 2 is operating, DC power is converted to AC power by the inverter 6 and supplied to the motor 2. When the motor 2 is regenerating power, the generated power is converted to DC power by the inverter 6 and charged to the battery 7. The operating state of the inverter 6 and the motor 2 is controlled by the motor control device 10.

[0024] The motor control device 10 is one of the electronic control units (M-ECU, Motor Electronic Control Unit) installed in the electric vehicle 1. The motor control device 10 has the function of controlling the operating state of the motor 2 so as torsional resonance between the motor 2 and the power transmission mechanism (reduction mechanism 3 and axle 4) and the wheels 5 is suppressed. The motor control device 10 incorporates a processor (central processing unit), memory (main memory), storage device, interface device, etc. (not shown), and these are connected to each other via an internal bus so as to be able to communicate with each other. The content of the decisions and controls performed by the motor control device 10 is recorded and stored in memory as firmware or application programs, and when the program is executed, the contents of the program are expanded into the memory space and executed by the processor.

[0025] The motor control device 10 is connected to a vehicle attitude control device 11 (vehicle attitude ECU), an accelerator sensor 12, a brake sensor 13, a steering angle sensor 14, a vehicle speed sensor 15, a yaw rate sensor 16, a motor angular velocity sensor 17, and a wheel speed sensor 18. These motor control device 10, vehicle attitude control device 11, and sensors are capable of communicating with each other via an in-vehicle communication network.

[0026] The vehicle attitude control device 11 is an electronic control device that sets the required torque for the motor 2 according to the vehicle speed, longitudinal acceleration, lateral acceleration, angular velocity, accelerator operation amount, brake operation amount, steering angle, etc. The motor control device 10 controls the operating state of the motor 2 based on the required torque and braking force set by the vehicle attitude control device 11. If the electric vehicle 1 is equipped with multiple motors 2, the operating state of each motor 2 can be controlled based on a known torque distribution method. In addition, the vehicle attitude control device 11 in this embodiment also has a function to calculate the slip ratio for each wheel 5 provided on the vehicle and the braking force required for each wheel 5. The slip ratio and braking force information calculated here is transmitted to the motor control device 10.

[0027] The acceleration sensor 12 is a sensor that detects the amount of depression (acceleration opening) of the accelerator pedal and the depression speed thereof. The brake sensor 13 is a sensor that detects the amount of depression (brake pedal stroke) of the brake pedal and the depression speed thereof. The steering angle sensor 14 is a sensor that detects the actual steering angle of the wheel 5 and the steering angle of the steering. The vehicle speed sensor 15 is a sensor that detects the vehicle body speed V (the moving speed of the vehicle center of gravity), which is the vehicle speed of the electric vehicle 1.

[0028] The yaw rate sensor 16 is a sensor that detects the yaw rate (angular velocity in the yaw direction) acting on the center of gravity of the electric vehicle 1. The motor angular velocity sensor 17 is a sensor that detects the rotational angular velocity (motor angular velocity ω M ) of the motor 2. The wheel speed sensor 18 is a sensor that detects the rotational angular velocity of the wheel 5 (or the axle 4), and is individually provided near each of the left and right wheels 5.

[0029] [2. Control Configuration] (A) Overall Configuration FIG. 2 is a block diagram showing the flow of motor control in the motor control device 10. The motor control device 10 is provided with an FF calculation unit 20 (feedforward calculation unit, calculation unit), a FB calculation unit 30 (feedback calculation unit), and a control unit 40. These elements are shown by classifying the functions of the motor control device 10 for convenience. These elements can be described as independent programs, or can be described as a composite program in which a plurality of elements are combined. The programs corresponding to each element are stored in the memory or storage device of the motor control device 10 and are to be executed by a processor.

[0030] The FF calculation unit 20 calculates an FF vibration suppression torque T ff (feedforward vibration suppression torque, vibration suppression torque), which is an input torque to the power transmission mechanism for suppressing torsional resonance, based on a transfer function representing the vibration characteristics of the power transmission mechanism and the required torque of the motor 2. The FF calculation unit 20 calculates at least the load side inertia J that changes according to the slip state of the wheel 5 loadIt has an inertia map 23 in which the load-side inertia J related to the transfer function is defined. load This is set based on the inertia map 23. The specific configuration of the FF calculation unit 20 will be described later.

[0031] The FB calculation unit 30 calculates the motor angular velocity ω M Based on the corresponding angular velocity, the FB vibration damping torque T is a feedback correction torque used to suppress torsional resonance. fb This calculates the (feedback vibration damping torque). In this embodiment, the motor angular velocity ω M The motor-side angular velocity ω of the power transmission mechanism corresponding to this m Based on this, FB vibration damping torque T fb The FB calculation unit 30 has a gain map 35 in which the feedback gain that changes according to the slip state of at least the wheel 5 is defined. FB vibration damping torque T fb The feedback gain used in the calculation is set based on the gain map 35. The specific configuration of the FB calculation unit 30 will be described later. Note that the FB calculation unit 30 in this embodiment is optional.

[0032] The control unit 40 controls the FF vibration damping torque T ff and FB vibration damping torque T fb Based on this, the motor 2 is controlled. If the FB calculation unit 30 is omitted, the control unit 40 controls the FF vibration damping torque T ff The motor 2 is controlled based on the following. Here, for example, in the plant 41 of the control unit 40, the FF vibration damping torque T ff (Or, FF vibration damping torque T ff From FB vibration damping torque T fb The motor-side angular velocity ω of the power transmission mechanism when a torque (minus the magnitude of the torque) is input to the power transmission mechanism. m This is calculated. Plant 41 stores an approximate model for understanding the operation of the drive system. Subsequently, the angular velocity input to the power transmission mechanism is the motor-side angular velocity ω m The operating state of the inverter 6 is controlled to match the desired motor angular velocity ω. M This will be realized.

[0033] Figure 3 shows the motor torque T in the power transmission mechanism. M and motor angular velocity ω M This is a schematic diagram showing the relationship. The power transmission mechanism in this embodiment is modeled as a two-inertia spring-mass damper in the tire linear region. T in Figure 3 m This is the motor-side torque in the power transmission mechanism (the torque of the motor-side mass among the two masses connected by a spring and a damper), and T ds is the axle-side torque in the power transmission mechanism (the torque of the axle-side mass out of the two masses). G is the reduction ratio of the reduction mechanism 3, and K s is the elastic modulus of the spring, and D s is the viscosity coefficient of the damper. Also, J m is motor inertia, J load This is the load-side inertia, J w is wheel inertia, θ s is the angle of twist, ω m ω is the motor-side angular velocity in the power transmission mechanism. w This is the wheel angular velocity.

[0034] Motor side torque T m Motor Torque T M It is calculated by multiplying by the reduction ratio G. Also, the motor-side angular velocity ω m The motor side torque T m Torque T from the axle side ds The value obtained by subtracting "1 / (J)" is "1 / (J m It is calculated by multiplying by "·s)" and the motor angular velocity ω M ω is the motor-side angular velocity m It is calculated by multiplying by "1 / G". Axle-side torque T ds ω is the motor-side angular velocity m From wheel angular velocity ω w The value A (A=ω) obtained by subtracting the value of ω m -ω w It is calculated by adding the elastic contribution torque and the viscous contribution torque, which are calculated based on ).

[0035] The elastic contribution torque is the torsional angle θ obtained by multiplying the value A by "1 / s". s and elastic modulus Ks The viscous torque is calculated as the product of the two values ​​A and the viscosity coefficient D. s It is calculated as the product of the two. Also, the wheel angular velocity ω w The axle side torque T ds ni "1 / (J load It is calculated by multiplying by "·s". A model of such a power transmission mechanism is stored in the plant 41 of the control unit 40. In addition, in this power transmission mechanism, the axle side torque T ds and motor side torque T m The transfer function representing the relationship is expressed as shown in Equation 1 below. Such a transfer function is stored in the motor angular velocity calculation unit 21 of the FF calculation unit 20, which will be described later.

[0036]

number

[0037] T m : Torque on the motor side of the power transmission mechanism T ds Torque on the axle side of the power transmission mechanism K s : Elastic modulus of power transmission mechanism D s Viscosity coefficient of power transmission mechanism J m Motor Inertia J load Load-side inertia

[0038] (B)FF calculation section The specific configuration of the FF calculation unit 20 will now be described. As shown in Figure 2, the FF calculation unit 20 includes a motor angular velocity calculation unit 21, a frequency filter unit 22, and an inertia map 23. The motor angular velocity calculation unit 21 calculates a value (T) representing the torque oscillation state of the power transmission mechanism based on the aforementioned transfer function and the required torque of the motor 2 set by the vehicle attitude control device 11. ds / T m The frequency filter unit 22 calculates the value (T) calculated by the motor angular velocity calculation unit 21. ds / T mThis suppresses torsional resonance by filtering out predetermined frequency components contained in the ). The value output from the frequency filter unit 22 is the FF vibration damping torque T ff (This becomes one of the input torques to the power transmission mechanism used to suppress torsional resonance.)

[0039] The inertia map 23 shows the load-side inertia J related to the aforementioned transfer function. load This is a map that defines the characteristics for setting the inertia. The inertia map 23 includes at least the slip ratio of the wheel 5 and the load-side inertia J. load The relationship between the slip ratio and the load-side inertia J is defined. Here, the slip ratio and the load-side inertia J are defined. load The relationship is illustrated in Figure 4(A). Load-side inertia J load The value is set to a larger value when the slip ratio is small, and to a smaller value when the slip ratio is large.

[0040] The inertia map 23 of this embodiment includes the slip ratio of wheel 5, the braking force, and the load-side inertia J. load The relationship between these three parties is defined. In other words, the inertia map 23 of this embodiment is defined by the slip ratio of the wheel 5, the braking force, and the load-side inertia J. load This is a three-dimensional map that defines the relationship between the braking force and the load-side inertia J when the slip ratio is fixed to a constant value. load The relationship is illustrated in Figure 4(B). Load-side inertia J load The setting is smaller when the braking force is small, and larger when the braking force is large. Note that the graph shapes shown in Figures 4(A) and (B) have no particular significance.

[0041] Load-side inertia J load A known method may be used to calculate the slip ratio related to the setting. For example, the vehicle speed V of the electric vehicle 1 and the wheel speed V of each wheel 5. w The slip ratio of each wheel 5 may be calculated based on this. The wheel speed V detected by the wheel speed sensor 18 w The difference between the vehicle speed V detected by the vehicle speed sensor 15 and (V wThe value obtained by dividing (-V) by the vehicle body speed V is defined as the slip ratio, and the load side inertia J is determined based on the slip ratios of the left and right wheels 5. load Alternatively, the wheel speed V of each wheel 5 may be estimated based on the motor angular velocity ω detected by the motor angular velocity sensor 17. M Based on this, the slip ratio may be calculated based on the estimated wheel speed V and the vehicle body speed V. w Based on the estimated wheel speed V w and the vehicle body speed V.

[0042] In addition, the reference speed V of each wheel 5 (i.e., the centroid movement speed of each wheel 5) with the influence of the turning operation corrected based on the vehicle body speed V and the yaw rate of the electric vehicle 1 is calculated, and the slip ratio is calculated based on the wheel speed V n and the reference speed V. w As the value of the slip ratio input to the inertia map 23, any one of the slip ratios of the left and right wheels 5 (for example, the minimum value or the maximum value) may be used, the average value may be used, or a value calculated based on a plurality of slip ratios (the slip ratios of the left and right two wheels or the four wheels) may be used. n For the calculation method of the braking force related to the setting of the load side inertia J, a known method may be adopted. For example, any one of the braking forces of the left and right wheels 5 driven by the motor 2 (for example, the minimum value or the maximum value) may be used, the average value may be used, or a value calculated based on a plurality of braking forces (the braking forces of the left and right two wheels or the four wheels) may be used. Also, a value calculated based on the left - right difference of the braking forces of the left and right wheels 5 may be used.

[0043] Load side inertia J load For the calculation method of the braking force related to the setting of the load side inertia J, a known method may be adopted. For example, any one of the braking forces of the left and right wheels 5 driven by the motor 2 (for example, the minimum value or the maximum value) may be used, the average value may be used, or a value calculated based on a plurality of braking forces (the braking forces of the left and right two wheels or the four wheels) may be used. Also, a value calculated based on the left - right difference of the braking forces of the left and right wheels 5 may be used.

[0044] (C) FB calculation unit The specific configuration of the FB calculation unit 30 will be described. As shown in FIG. 2, the FB calculation unit 30 includes a PID control amount calculation unit 31, a speed limit unit 32, a frequency filter unit 33, a saturator unit 34, a gain map 35, a correction coefficient map 36, and a multiplication unit 37. The PID control amount calculation unit 31 calculates the motor - side angular velocity ω mBased on this, the feedback correction amount related to PID control is calculated. Here, the motor-side angular velocity ω m Based on this, three types of feedback correction amounts are calculated: a proportional term correction amount, an integral term correction amount, and a differential term correction amount. These three types of feedback correction amounts are then added together and transmitted to the speed limiting unit 32.

[0045] The speed limiting unit 32 is a limiter that restricts the differential value, which is the time-varying gradient of the summed feedback correction amount, to a predetermined range. The frequency filter unit 33 suppresses torsional resonance by filtering out predetermined frequency components included in the output value of the speed limiting unit 32. The saturator unit 34 limits the upper and lower limits of the output value of the frequency filter unit 33. The value output from the saturator unit 34 is the FB vibration damping torque T fb (This becomes one of the input torques to the power transmission mechanism used to suppress torsional resonance.)

[0046] The gain map 35 is a map that defines the characteristics for setting the gain (feedback gain) of each feedback correction amount calculated by the PID control amount calculation unit 31. The gain map 35 defines at least the relationship between the slip ratio of the wheel 5 and the feedback gain. Here, the relationship between the slip ratio and the feedback gain is illustrated in Figure 5(A). The feedback gain is set to be larger as the slip ratio is smaller, and to be set to be smaller as the slip ratio is larger.

[0047] The gain map 35 of this embodiment includes the slip ratio of the wheel 5, the braking force, and the feedback gain (proportional term gain k). p , integral term gain k i , differential term gain k d) The three-way relationship with is defined. Here, for each of the three types of feedback gains, the relationship with the slip ratio and the braking force is defined. In other words, the gain map 35 of this embodiment is a three-dimensional map that defines the relationship between the slip ratio of the wheel 5, the braking force, and each feedback gain, and maps of the number corresponding to the number of types of feedback gains (three in this embodiment) are prepared.

[0048] Here, the relationship between the braking force and any one of the feedback gains when the slip ratio is fixed at a constant value is illustrated in FIG. 5(B). The feedback gain is set to be smaller as the braking force is smaller, and larger as the braking force is larger. Note that there is no particular meaning in the magnitude relationship or the graph shape of each feedback gain (proportional term gain k p , integral term gain k i , derivative term gain k d ) shown in FIGS. 5(A) and 5(B).

[0049] The correction coefficient map 36 is a map that defines the relationship between the correction coefficient C multiplied by the feedback gain and the vehicle body speed V (or the wheel speed V w ) of the electric vehicle 1. In the correction coefficient map 36, for example, the relationship between the vehicle body speed V and the correction coefficient C is defined. Here, the relationship between the vehicle body speed V and the correction coefficient C is illustrated in FIG. 5(C). The correction coefficient C is set to be smaller as the vehicle body speed V is larger, and larger as the vehicle body speed V is smaller. Note that there is no particular meaning in the graph shape shown in FIG. 5(C).

[0050] The multiplication unit 37 multiplies the product of each feedback gain obtained from the gain map 35 and the correction coefficient C obtained from the correction coefficient map 36 as the final control feedback gain (control proportional term gain K p , control integral term gain K i , control derivative term gain K d ) and inputs it to the PID control amount calculation unit 31. The PID control amount calculation unit 31 is the motor-side angular velocity ω described above mBased on the control feedback gain, three types of feedback correction amounts (proportional term correction amount, integral term correction amount, and differential term correction amount) are calculated and their sum is transmitted to the speed limiting unit 32. In this way, the FB calculation unit 30 of this embodiment uses the product of the correction coefficient C obtained based on the correction coefficient map 36 and each feedback gain obtained in the gain map 35 to calculate the FB vibration damping torque T fb Calculate.

[0051] Feedback gain (proportional term gain k) p , integral term gain k i , differential term gain k d As for the method for calculating the slip ratio related to the setting of ), a known method may be adopted, or the load-side inertia J load The same value as the slip ratio related to the setting may be used, and the load-side inertia J load A different value from the slip ratio used in the setting may be used. Also, the reference speed V of each wheel 5, which has been corrected for the effect of turning based on the vehicle speed V and the yaw rate of the electric vehicle 1. n (That is, the center of gravity movement speed of each wheel 5) is calculated, and the wheel speed V w and reference speed V n The slip ratio may be calculated based on the above. The slip ratio value input to the gain map 35 may be either the slip ratio of each left and right wheel 5 (for example, the minimum or maximum value), the average value, or a value calculated based on multiple slip ratios (slip ratio of the two left and right wheels or slip ratio of all four wheels).

[0052] Similarly, feedback gain (proportional term gain k p , integral term gain k i , differential term gain k d As for the method for calculating the braking force related to the setting of ), a known method may be adopted, or the load-side inertia J load The same value as the braking force related to the setting may be used, and the load-side inertia J loadA value different from the braking force used in the setting may be used. For example, one of the braking forces of each left and right wheel 5 (e.g., the minimum or maximum value) may be used, the average value may be used, or a value calculated based on multiple braking forces (the braking forces of the two left and right wheels or the braking forces of all four wheels) may be used. Alternatively, a value calculated based on the difference in braking force between the left and right wheels 5 may be used.

[0053] Furthermore, when setting the correction coefficient C, instead of the vehicle speed V, any wheel speed V detected by the wheel speed sensor 18 is used. w You may use (for example, the minimum or maximum value), or you may use their average value, or multiple wheel speeds V w Alternatively, a value calculated based on the vehicle speed V may be used.

[0054] [3. Effects] (1) The motor control device 10 of this embodiment is a motor control device 10 that controls the operating state of the motor 2 in an electric vehicle 1 equipped with a motor 2 that drives the wheels 5 via a power transmission mechanism (reduction mechanism 3, axle 4), so as torsional resonance between the motor 2, the wheels 5 and the power transmission mechanism is suppressed. Based on the transfer function representing the vibration characteristics of the power transmission mechanism and the required torque of the motor 2, the motor control device 10 controls the FF vibration damping torque T, which is the input torque to the power transmission mechanism to suppress torsional resonance. ff The FF calculation unit 20 calculates the FF vibration damping torque T ff The system includes a control unit 40 that controls the motor 2 based on the FF calculation unit 20, which controls the load-side inertia J which changes according to at least the slip state of the wheels 5. load It has an inertia map 23 in which the load-side inertia J related to the transfer function is defined based on the inertia map 23. load Set it.

[0055] In this way, the load-side inertia J of the power transmission mechanism changes according to the slip state of wheel 5. loadBy defining this in the inertia map 23, the motion state of the drive system in a slip state can be accurately grasped, and even when the slip state of wheel 5 is high, torsional resonance is suppressed by the FF vibration damping torque T. ff This allows for accurate calculation. Therefore, the controllability of motor 2 can be improved with a simple configuration.

[0056] (2) The inertia map 23 of this embodiment shows the slip ratio of the wheel 5, the braking force and the load-side inertia J load This is a three-dimensional map that defines the relationship with the load side inertia J. load By setting the load-side inertia J considering not only the slip ratio of wheel 5 but also the braking force applied to wheel 5, load This improves the approximation accuracy. Therefore, FF vibration damping torque T ff This allows for further improvement in the calculation accuracy and further improvement in the controllability of motor 2.

[0057] (3) The slip ratio described above is determined by the vehicle speed V and wheel speed V of the electric vehicle 1. w It can be calculated based on the wheel speed V detected by the wheel speed sensor 18. w The difference between the vehicle speed V detected by the vehicle speed sensor 15 and (V w The slip ratio can be calculated by dividing (-V) by the vehicle speed V. This allows for quick and accurate determination of the slip state of each individual wheel 5. Therefore, the controllability of the motor 2 can be further improved.

[0058] (4) The above wheel speed V w This may be the value detected by the wheel speed sensor 18, or the motor angular velocity ω detected by the motor angular velocity sensor 17. M The value may be calculated based on the former. In the former case, the controllability of the motor 2 can be improved by emphasizing the slip state of the wheel 5. In the latter case, the controllability of the motor 2 can be improved by emphasizing its current operating state.

[0059] (5) The above wheel speed V wThis may be a value calculated based on the vehicle speed V and the yaw rate of the electric vehicle 1. That is, the reference speed V of the wheels corrected for the effect of turning motion based on the vehicle speed V and yaw rate. n Calculate the wheel speed V w and reference speed V n The slip ratio may be calculated based on this. This allows for a more accurate understanding of the drive system's motion during a slip condition while turning, further improving the controllability of the motor 2.

[0060] (6) The FF calculation unit 20 calculates the load-side inertia J based on either the minimum or maximum slip ratio of the left and right wheels 5 (left and right wheels) driven by the motor 2, or the average value of the slip ratios. load This can be set. In the former case, the controllability of motor 2 can be improved by prioritizing the motion state of either the left or right wheel driven by motor 2. For example, the load-side inertia J based on the minimum slip ratio of each of the left and right wheels. load According to the settings, the dynamic state of the drive system can be understood by assuming that wheel 5 is not slipping as much as it actually is. On the other hand, the load-side inertia J is based on the maximum slip ratio of each of the left and right wheels. load According to this setting, the dynamic state of the drive system can be understood by assuming that wheel 5 is slipping more than it actually is. In the latter case, the controllability of motor 2 can be improved by emphasizing the average dynamic state of the left and right wheels driven by motor 2.

[0061] (7) The above braking force is calculated based on the maximum value of each braking force at the left and right wheels 5 (left and right wheels) driven by the motor 2, or the difference between the left and right braking forces. Based on this, the load-side inertia J is calculated based on the braking force actually acting on the wheels 5. load This setting allows you to control the FF vibration damping torque T, which suppresses torsional resonance. ff This allows for accurate calculation. Therefore, the controllability of motor 2 can be further improved with a simple configuration.

[0062] (8) In this embodiment, the transfer function representing the vibration characteristics of the power transmission mechanism is the axle-side torque T of the power transmission mechanism as shown in Equation 1.ds and motor side torque T m This is a transfer function that represents the relationship. In this way, by modeling the power transmission mechanism with a two-inertia spring-mass damper in the tire linear region, the torque oscillation state of the power transmission mechanism (reduction mechanism 3 and axle 4) can be accurately grasped. Therefore, the controllability of motor 2 can be further improved.

[0063] [4. Others] The above embodiments are merely illustrative examples, and there is no intention to exclude various modifications or applications of techniques not explicitly stated in these embodiments. Each configuration of these embodiments can be modified in various ways without departing from their intended purpose. Furthermore, each configuration of these embodiments can be selected or combined as needed.

[0064] In the above embodiment, an electric vehicle 1 equipped with a single motor 2 was illustrated, but the motor control described herein is also applicable to an electric vehicle 1 equipped with a pair of left and right motors 2 and a reduction mechanism 3 that also functions as a power distribution mechanism. At the very least, when controlling the operating state of the motor 2 so as torsional resonance is suppressed, the load-side inertia J load By changing this according to the slip state of wheel 5, the same control as in the above embodiment can be implemented, and the same operation and effect as in the above embodiment can be obtained.

[0065] In the above embodiment, a vehicle attitude control device 11 for setting the required torque was illustrated, but the required torque may be set by another electronic control device, or the motor control device 10 may be configured to set the required torque internally. The same applies to the calculation of slip ratio and braking force; these may be calculated by another electronic control device, or by the motor control device 10. [Industrial applicability]

[0066] This technology is applicable to the manufacturing industry of motor control devices installed in electric vehicles, and also to the manufacturing industry of electric vehicles equipped with motor control devices. [Explanation of symbols]

[0067] 1. Electric Vehicle 2 motors 3 Reduction mechanism 4 axles 5 wheels (left and right wheels) 6 Inverters 7 batteries 10 Motor control device 11. Vehicle attitude control system 12. Accelerator sensor 13 Brake sensor 14. Steering angle sensor 15. Vehicle speed sensor 16 Yaw rate sensor 17. Motor angular velocity sensor 18. Wheel speed sensor 20 FF Calculation Unit (Calculation Unit) 21 Motor angular velocity calculation unit 22 Frequency filter section 23 Inertia Map (Map) 30 FB calculation unit 31 PID control variable calculation unit 32 Speed ​​limit section 33 Frequency filter section 34 Saturator section 35 Gain Map 36 Correction Factor Map 37 Multiplication section 40 Control Unit 41 Plant J load Load-side inertia T ff Feedforward vibration damping torque (vibration damping torque) T fb Feedback vibration damping torque

Claims

1. In an electric vehicle equipped with a motor that drives wheels via a power transmission mechanism, a motor control device controls the operating state of the motor so as torsional resonance between the motor, the wheels, and the power transmission mechanism is suppressed, A calculation unit calculates a vibration damping torque, which is the input torque to the power transmission mechanism for suppressing torsional resonance, by filtering predetermined frequency components of the torque vibration state obtained by substituting the load-side inertia into the transfer function, based on the transfer function representing the vibration characteristics of the power transmission mechanism based on a two-inertia spring-damper system model in the tire linear region and the required torque of the motor, and the input torque to the power transmission mechanism for suppressing torsional resonance. The system includes a control unit that controls the motor based on the vibration damping torque, The calculation unit has a map that defines the load-side inertia which changes according to at least the slip state of the wheel, and sets the load-side inertia related to the transfer function based on the map and substitutes it into the transfer function. A motor control device characterized by the following features.

2. The aforementioned map is a three-dimensional map that defines the relationship between the slip ratio of the wheel, the braking force, and the load-side inertia. A motor control device according to claim 1, characterized in that

3. The slip ratio is calculated based on the vehicle speed and wheel speed of the electric vehicle. The motor control device according to claim 2, characterized in that

4. The wheel speed is a value obtained by detecting a wheel speed sensor, or a value calculated based on the detected motor angular velocity. A motor control device according to claim 3, characterized in that

5. Based on the vehicle speed and the yaw rate of the electric vehicle, a reference speed of the wheel is calculated, corrected for the effect of turning motion, and the slip ratio is calculated based on the wheel speed and the reference speed. A motor control device according to claim 3, characterized in that

6. The calculation unit sets the load-side inertia based on either the slip ratio of the left and right wheels driven by the motor, or the average value of the respective slip ratios. The motor control device according to claim 2, characterized in that

7. The braking force is calculated based on the maximum value of the braking force of each of the left and right wheels driven by the motor, or the difference between the left and right braking forces. The motor control device according to claim 2, characterized in that

8. The aforementioned transfer function is a transfer function that represents the relationship between the axle-side torque and the motor-side torque of the power transmission mechanism shown below. A motor control device according to claim 1, characterized in that [Math 1]

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