Control method for electric vehicles, and control system for electric vehicles

Abstract

The objective is to provide a control method and control system for electric vehicles that can achieve both stability and responsiveness to disturbances in feedback control. [Solution] A method for controlling an electric vehicle in which, in order to generate a first torque command value by damping the target torque based on an inverse model of the vehicle model, a second torque command value is generated by multiplying the value obtained by inputting the difference between the estimated and detected rotational speed of the drive motor into a filter represented by the product of the inverse model and a bandpass filter by a predetermined feedback gain, and a final torque command value is generated by adding the first torque command value and the second torque command value and converting it into a PWM signal, the carrier frequency of the PWM signal is set to a set value relating to the region that includes the operating point in coordinate space, wherein the feedback gain is set based on the magnitude of the set value relating to the region that includes the operating point.

Description

[Technical Field]

[0001] The present invention relates to a control method for electric vehicles and a control system for electric vehicles. [Background technology]

[0002] Patent Document 1 discloses a technique for generating a first torque command value by applying vibration damping to a target torque generated based on a driver's request, based on an inverse model of a vehicle model that models the drive force transmission system of an electric vehicle that transmits the driving force of a drive motor to the drive wheels; generating a second torque command value by multiplying the difference between the estimated value of the drive motor's rotational speed obtained by inputting the first torque command value into the vehicle model and the detected value of the drive motor's rotational speed by a predetermined feedback gain, inputting the difference into a filter represented by the product of the inverse model and a bandpass filter with the resonant frequency of the drive force transmission system as the center frequency, and adding the first torque command value and the second torque command value together to generate a final torque command value, and converting the final torque command value into a PWM signal for controlling the drive motor. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2005-269833 [Overview of the Initiative] [Problems that the invention aims to solve]

[0004] However, if the carrier frequency of the PWM signal is set individually according to the position of the operating point of the drive motor in a coordinate space with the drive motor's torque and rotational speed as axes, attempting to ensure the stability of the feedback control with a single gain for all carrier frequency settings will not allow for sufficient disturbance responsiveness of the feedback control in the high carrier frequency range.

[0005] The present invention aims to provide a control method and a control system for electric vehicles that can achieve both stability of feedback control and responsiveness to disturbances, even when the carrier frequency of the PWM signal is individually set according to the position of the operating point of the drive motor in a coordinate space with the torque and rotational speed of the drive motor as axes. [Means for solving the problem]

[0006] The electric vehicle control method according to the present invention generates a first torque command value by applying vibration damping processing to a target torque generated based on the driver's request based on an inverse model of a vehicle model that models the drive force transmission system of an electric vehicle that transmits the driving force of a drive motor to the drive wheels. The difference between the estimated value of the rotational speed of the drive motor obtained by inputting the first torque command value into the vehicle model and the detected value of the rotational speed of the drive motor is input into a filter represented by the product of the inverse model and a bandpass filter whose center frequency is the resonant frequency of the drive force transmission system, and the value obtained is multiplied by a predetermined feedback gain to generate a second torque command value. The final torque command value is generated by adding the first torque command value and the second torque command value together. When the final torque command value is converted into a PWM signal for controlling the drive motor, the coordinate space with the rotational speed of the drive motor and the final torque command value as axes is divided into multiple regions, and the carrier frequency setting value of the PWM signal is set individually for each region, and the carrier frequency is set to the setting value for the region that includes the operating point of the drive motor in the coordinate space. In this control method, the feedback gain is set based on the magnitude of the set value related to the region containing the operating point. [Effects of the Invention]

[0007] According to the present invention, a feedback gain that balances the stability of feedback control and the responsiveness to disturbances can be set according to the carrier frequency, thereby maintaining the stability of motor control and good responsiveness. In a drive motor, the carrier frequency is varied according to the rotational speed and torque, taking into account control tracking performance and semiconductor losses. For example, it is set higher than the normal value during high-speed driving and lowered in situations where motor lock may occur. In the present invention, the feedback gain is calculated based on the variable carrier frequency. This takes into account control tracking performance and semiconductor losses, suppresses abrupt changes in the input variable of the feedback control, and suppresses fluctuations in the acceleration of the electric vehicle. [Brief explanation of the drawing]

[0008] [Figure 1] Figure 1 shows the overall configuration of an electric vehicle to which the electric vehicle control system of this embodiment is applied. [Figure 2] Figure 2 is a block diagram showing the specific configuration of the motor torque setting unit, vibration damping control unit, etc. [Figure 3] Figure 3 is a block diagram showing the specific configuration of the gain multiplication section that constitutes the vibration damping control unit. [Figure 4] Figure 4 shows an example of a carrier frequency map with the motor torque and rotational speed of the drive motor as input values. [Figure 5] Figure 5 is a block diagram of the predictive torque command value calculation unit. [Figure 6] Figure 6 is a block diagram of the predictive rotation speed calculation unit. [Figure 7] Figure 7 is a time chart of the control system for the electric vehicle of this embodiment. [Figure 8] Figure 8 is a time chart of the control system for the electric vehicle of this embodiment, showing the case where the drive wheels lock during deceleration. [Figure 9]Figure 9 shows a characteristic curve (gain map) representing the conditions under which both disturbance responsiveness and stability of feedback control can be achieved in a coordinate space with the feedback gain and carrier frequency as axes, and the trajectory of the operating point in the coordinate space controlled by this embodiment. [Modes for carrying out the invention]

[0009] Embodiments of the present invention will be described below with reference to the attached drawings.

[0010] Figure 1 shows the overall configuration of an electric vehicle to which the electric vehicle control system of this embodiment is applied. This vehicle is driven by the driving force of a three-phase AC drive motor 5 being transmitted to the drive wheels 8a and 8b via a drive force transmission system 7 (reduction gear, differential gear, drive shaft). The rotational speed sensor 6 detects the rotational speed (N) of the drive motor 5.

[0011] The accelerator position sensor 1 detects the accelerator position (APO) and outputs it to the motor torque setting unit 2. The motor torque setting unit 2 sets a first torque command value (Tm1) based on the accelerator position (APO) detected by the accelerator position sensor 1 and the rotational speed (N) of the drive motor 5 detected by the rotational speed sensor 6. * Calculate ).

[0012] The vibration control unit 3 receives the first torque command value (Tm1) set by the motor torque setting unit 2. * Based on the rotational speed of the drive motor 5 detected by the rotational speed sensor 6, the final motor torque command value (Tmf * Calculate ).

[0013] The motor torque control unit 4 receives the final motor torque command value (Tmf) calculated by the vibration damping control unit 3. *) is converted into a dq-axis current command value, a dq-axis voltage command value is calculated based on the difference between the dq-axis current command value and the detected dq-axis current value flowing through the drive motor 5, the dq-axis voltage command value is converted into three-phase voltage command values, the three-phase voltage command values are converted into PWM signals, and the PWM signals are output to an inverter (not shown) that outputs an alternating current to the drive motor 5.

[0014] The motor torque control unit 4 sets the carrier frequency (f) of the PWM signal by inputting the final torque command value (Tmf * ) and the rotational speed (N) of the drive motor 5 into the map shown in FIG. 4 described later.

[0015] FIG. 2 is a block diagram showing the specific configurations of the motor torque setting unit 2, the vibration suppression control unit 3, etc. The motor torque setting unit 2 includes a torque map 21 and a control block 22 having characteristics of Gm(s) (Gp(s)) -1 . Gp(s) is a model showing the transfer characteristics between the torque input to the vehicle and the motor rotational speed, and Gm(s) is a model (ideal model) showing the transfer characteristics between the torque input to the vehicle and the response target of the motor rotational speed. Since Gp(s) and Gm(s) are prior arts (see Patent Document 1), detailed descriptions thereof are omitted.

[0016] The torque map 21 is a map showing the relationship between the rotational speed (N) of the drive motor 5 and the motor torque of the drive motor 5 (such as the final torque command value (Tmf * )) for a plurality of accelerator opening degrees, and based on the accelerator opening (APO) detected by the accelerator opening sensor 1 and the rotational speed (N) of the drive motor 5 detected by the rotational speed sensor 6, the target torque (T * [[ID=二十]]) is obtained. The control block 22 performs feedforward control to suppress the vibration of the vehicle. That is, by passing the target torque (T * ) through a filter of Gm(s) / Gp(s), a first torque command value (Tm1 * ) with a high vibration suppression effect (especially the vibration suppression effect on the drive shaft torsional vibration) is obtained.

[0017] The vibration control unit 3 includes a control block 31 having a transmission characteristic (Gp(s)), a subtractor 32, and H(s)(Gp(s)) -1 The system comprises a control block 33 having a transmission characteristic, an adder 34, a gain multiplier 35, and an adder 36 (optional). The adder 34 receives the first torque command value (Tm1) output from the control block 22. * ) and the third torque command value (Tm3) output from the gain multiplication unit 35, which will be described later. * Add ) to get the final torque command value (Tmf * Calculate ).

[0018] Addition result by adder 34 (final torque command value (Tmf) * The final torque command value (Tmf) added by the adder 34 is input to the drive motor 5 via the motor torque control unit 4 (Figure 1). In Figure 2, the control block representing the drive motor 5 is represented by a control block 11 having a transmission characteristic of Gp(s). The control block 11 is also input to the final torque command value (Tmf) added by the adder 34. * The sum of the externally input disturbance (Td) and the sum of the two values ​​are input.

[0019] The adder 36 receives the first torque command value (Tm1) output from the control block 22. * ) and the second torque command value (Tm2) output from the control block 33, which will be described later. * ) is added together to obtain the fourth torque command value (Tm4 * The control block 31 calculates the fourth torque target value (Tm4) output from the adder 36. * )(If adder 36 is omitted, the first torque command value (Tm1 * Based on the above, the estimated rotational speed (ωm^) of the drive motor 5 is calculated. The subtractor 32 calculates the difference between the estimated rotational speed (ωm^) of the drive motor 5 obtained by the control block 31 and the detected actual rotational speed (ωm) of the drive motor 5.

[0020] H(s)(Gp(s)) -1 The control block 33, which has the following transmission characteristics, sets a second torque target value (Tm2) based on the deviation (ωm^-ωm) input from the subtractor 32.* We determine the following. Here, H(s) has the characteristics of a bandpass filter whose center frequency matches the torsional resonance frequency of the driving force transmission system 7.

[0021] Furthermore, multiple control blocks 33 can be connected in parallel, one for each of the number of resonant frequencies of the different natural vibrations of the drive force transmission system 7 that transmits driving force from the drive motor 5 to the drive wheels 8a and 8b. Each control block 33 can be set so that different resonant frequencies are its center frequencies. For example, if an electric vehicle is equipped with a powertrain consisting of a drive motor 5 and an inverter (not shown), a control block (not shown) having a bandpass filter (H(s)) with the resonant frequency of the natural vibration of the powertrain as its center frequency may be constructed, and a parallel circuit between this and the control block 33 may be constructed.

[0022] The second torque target value (Tm2) calculated by the control block 33 * The second torque target value (Tm2) is input to the adder 36 and the gain multiplier 35. * ) is multiplied by the feedback gain (K) to obtain the third torque target value (Tm3 * The gain multiplication unit 35 is calculated as follows. Details of the gain multiplication unit 35 will be described later.

[0023] [Gain multiplication section 35] Figure 3 is a block diagram showing the specific configuration of the gain multiplication unit 35 that constitutes the vibration damping control unit 3. Figure 4 shows the motor torque (final torque command value (Tmf)) of the drive motor 5. * ), predictive torque command value (Tmf * LA This is an example of a carrier frequency (f) map with rotational speed (N) as input values. Figure 5 is a block diagram of the look-ahead torque command value calculation unit 352. Figure 6 is a block diagram of the look-ahead rotational speed calculation unit 353.

[0024] As shown in Figure 3, the gain multiplication unit 35 includes a notch filter 351, a look-ahead torque command value calculation unit 352, a look-ahead rotational speed calculation unit 353, a first map 354A (MAP1), a second map 354B (MAP2), a first base gain setting unit 355A, a second base gain setting unit 355B, a first rate processing unit 356A, a second rate processing unit 356B, and a selection unit 357.

[0025] The rotational speed (N) of the drive motor 5 is input to the notch filter 351 (band reject filter). The notch filter 351 (band reject filter) removes the vibration component contained in the rotational speed (N) and outputs the rotational speed (N) from which the vibration component has been removed (hereinafter simply referred to as rotational speed (N)) to the first map 354A and the look-ahead rotational speed calculation unit 353.

[0026] The look-ahead torque command value calculation unit 352 calculates the final torque command value (Tmf * The final torque command value (Tmf) is input. The look-ahead torque command value calculation unit 352 calculates the final torque command value (Tmf) * Using the time change of ), the final torque command value (Tmf) a predetermined time (look-ahead time: Δt, for example 1 [s]) ahead will be used. * ) The predictive torque command value (Tmf * LA ) is calculated and output to the second map 354B.

[0027] As shown in Figure 5, the look-ahead torque command value calculation unit 352 includes a differentiator 3521, a look-ahead coefficient multiplier 3522, a low-pass filter 3523, and an adder 3524.

[0028] Differentiator 3521 calculates the final torque command value (Tmf * ) is differentiated with respect to time, and the value obtained by differentiating with respect to time is (dTmf * The value of / dt) is output to the look-ahead coefficient multiplication unit 3522.

[0029] The look-ahead coefficient multiplication unit 3522 multiplies the value (dTmf) input from the differentiator 3521. * The value obtained by multiplying (dTmf) by the look-ahead coefficient (Δt, the predetermined time mentioned above) (dTmf *The formula ( / dt)Δt) is calculated and output to the low-pass filter 3523.

[0030] The low-pass filter 3523 removes noise from the value input from the look-ahead coefficient multiplier 3522 and outputs it to the adder 3524.

[0031] The adder 3524 sets the final torque command value (Tmf * ) and the output of the low-pass filter 3523 are added together to obtain the look-ahead torque command value (Tmf * LA Calculate ).

[0032] As shown in Figure 3, the rotational speed (N) is input to the look-ahead rotational speed calculation unit 353. The look-ahead rotational speed calculation unit 353 uses the time change of rotational speed (N) to determine the look-ahead rotational speed (N) that will be the rotational speed (N) at a predetermined time (Δt, for example, 1 [s]) ahead. LA ) is calculated and output to the second map 354B.

[0033] As shown in Figure 6, the look-ahead rotation speed calculation unit 353 includes a differentiator 3531, a look-ahead coefficient multiplier 3532, a low-pass filter 3533, and an adder 3534.

[0034] The differentiator 3531 takes the time derivative of the rotational speed (N) and outputs the value obtained by the time derivative (dN / dt) to the look-ahead coefficient multiplier 3532.

[0035] The look-ahead coefficient multiplier unit 3532 calculates a value ((dN / dt)Δt) by multiplying the value (dN / dt) input from the differentiator 3531 by a look-ahead coefficient (Δt, the predetermined time mentioned above), and outputs this to the low-pass filter 3533.

[0036] The low-pass filter 3533 removes noise from the value input from the look-ahead coefficient multiplier 3532 and outputs it to the adder 3534.

[0037] The adder 3524 adds the rotational speed (N) and the output of the low-pass filter 3523 to obtain the look-ahead torque rotational speed (N). LA Calculate ).

[0038] As shown in FIG. 3, in the first map 354A, the final torque command value (Tmf * ) and the rotational speed (N) are inputted.

[0039] As shown in FIG. 4, the first map 354A (the second map 354B) divides the coordinate space with the motor torque of the drive motor 5 and the rotational speed (N) of the drive motor 5 as axes into regions (E1) - (E7), and sets the carrier frequency (f) for each region.

[0040] Note that regarding the motor torque in FIG. 4, there is a relationship of T1 < T2 < T3 < T4, regarding the rotational speed (N), there is a relationship of N1 < N2 < N3 < N4 < N5, and regarding the carrier frequency (f), there is a relationship of f1 < f2 < f3 < f4 < f5 < f6.

[0041] Region (E1) occupies a region where the motor torque (the final torque command value (Tmf * ), the predictive torque command value (Tmf * LA )) is T4 or more and the rotational speed (N) is less than N1, and the carrier frequency (f) is set to f1.

[0042] Region (E2) occupies a region where the motor torque is T2 or more and less than T4, and the rotational speed (N) is less than N1, and the carrier frequency (f) is set to f2.

[0043] Region (E3) occupies a region where the rotational speed (N) is less than N2 and excludes regions (E1) and (E2), and the carrier frequency (f) is set to f3.

[0044] Region (E4) occupies a region where the motor torque is T3 or more and the rotational speed (N) is N2 or more and less than N4, and the carrier frequency (f) is set to f4.

[0045] Region (E5) occupies a region where the motor torque is less than T1 and the rotational speed (N) is N2 or more and less than N3, and the carrier frequency (f) is set to f4.

[0046] Region (E6) is the region where the rotational speed (N) is N2 or greater and less than N5, occupying the region excluding regions (E4) and (E5), and the carrier frequency (f) is set to f5.

[0047] Region (E7) occupies the region where the rotational speed (N) is N5 or higher, and the carrier frequency (f) is set to f6.

[0048] Map 1 354A is the final torque command value (Tmf * The rotational speed (N) and the operating point (P1) in Figure 4 are represented, the carrier frequency (f) related to the region containing the operating point (P1) is extracted, and the extracted carrier frequency (f) is output to the first base gain setting unit 355A.

[0049] As shown in Figure 3, the first base gain setting unit 355A has a map (characteristic curve) that represents the relationship between the carrier frequency (f) and the first base gain (K1). The map (characteristic curve) has the characteristic that as the carrier frequency (f) increases, the first base gain (K1) increases monotonically in a linear fashion.

[0050] The first base gain setting unit 355A sets the first base gain (K1) by inputting the input carrier frequency (f) into the map, and outputs this to the first rate processing unit 356A.

[0051] The first rate processing unit 356A receives the first base gain (K1) and the rotational speed (N) as inputs.

[0052] The first rate processing unit 356A compares the current value of the first base gain (K1) with the previous value, and if the current value is less than or equal to the previous value, it outputs the current value as is to the selection unit 357, as shown by the solid line (A).

[0053] The first rate processing unit 356A outputs to the selection unit 357 when the current value of the first base gain (K1) is higher than the previous value and the rotational speed (N) is equal to or greater than a predetermined rotational speed (N2 in Figure 4 (which is experimentally predetermined, for example, 1000 [rpm])), while monotonically increasing the first base gain (K1) at a relatively gradual rate of increase (for example, 0.1 [1 / sec]), as shown by the dashed line (B).

[0054] The first rate processing unit 356A outputs to the selection unit 357 when the current value of the first base gain (K1) is higher than the previous value and the rotational speed (N) is less than a predetermined threshold (for example, N2 in Figure 4), while increasing the first base gain (K1) from the previous value to the current value at a relatively steep rate of increase (for example, 1.0 [1 / sec]) as shown by the dashed line (C).

[0055] Torque ripple and powertrain resonance occur in the low-speed range where the rotational speed falls below a predetermined threshold. Therefore, to efficiently eliminate these unwanted vibrations, the rate of increase of the first base gain (K1) is increased in the low-speed range.

[0056] The second map 354B contains the look-ahead torque command value (Tmf * LA ) and the number of pre-read rotations (N LA ) is entered.

[0057] Map 354B is the look-ahead torque command value (Tmf * LA ) and lookahead rotation count (N LA The look-ahead operating point (P2) in Figure 4 is represented, the carrier frequency (f) related to the region containing the look-ahead operating point (P2) is extracted, and the extracted carrier frequency (f) is output to the second base gain setting unit 355B.

[0058] The second base gain setting unit 355B sets the second base gain (K2) by inputting the input carrier frequency (f) into its map and outputs this to the second rate processing unit 356B. The second base gain setting unit 355B has a map common to the first base gain setting unit 355A.

[0059] The second rate processing unit 356B receives the second base gain (K2) as input.

[0060] The second rate processing unit 356B compares the current value of the second base gain (K2) with the previous value, and if the current value is greater than or equal to the previous value, it outputs the current value as is to the selection unit 357, as shown by the solid line (A).

[0061] The second rate processing unit 356B calculates a reduction rate such that the second base gain (K2) transitions from the previous value to the current value within the look-ahead time (Δt), regardless of the difference between the current value and the previous value, when the current value of the second base gain (K2) is lower than the previous value. The second rate processing unit 356B calculates the reduction rate, for example, by (current value - previous value) / Δt. Then, the second rate processing unit 356B reduces the second base gain (K2) from the previous value to the current value according to the calculated reduction rate and outputs it to the selection unit 357.

[0062] The selection unit 357 sets the lower of the first base gain (K1) output from the first rate processing unit 356A and the second base gain (K2) output from the second rate processing unit 356B as the feedback gain (K).

[0063] Furthermore, if the values ​​of the first base gain (K1) and the second base gain (K2) match, the selection unit 357 sets one of them as the feedback gain (K).

[0064] [Time Chart] Figure 7 is a time chart of the control system for the electric vehicle of this embodiment. Here, the final torque command value (Tmf * The time evolution of the feedback gain is shown when the operating point (P1), represented by the rotational speed (N), moves in the order of points (A), (B), (C), and (D) as shown in Figure 4.

[0065] Before time t0, the operating point (P1) is stopped at position (A) (Figure 4). At this time, the target torque (T * ) maintains a predetermined low torque target value higher than zero, and the final torque command value (Tmf * The torque (Tmf) also maintains the low torque target value, and the rotational speed (N) also maintains the predetermined low rotational speed. * LA ) is the final torque command value (Tmf * ) matches, and the number of lookahead rotations (N LA ) is equal to the rotational speed (N). Therefore, the predictive torque command value (Tmf * LA ) and lookahead rotation count (N LA The position of the look-ahead operating point (P2) represented by ) is point (A), just like the operating point (P1).

[0066] The carrier frequency (f) extracted by the first map 354A (MAP1) is set to the value (f3) set in the region (E3) that encompasses the operating point (P1) (=point (A)). The carrier frequency (f) extracted by the second map 354B (MAP2) is set to the value (f3) set in the region (E3) that encompasses the look-ahead operating point (P2) (=point (A)).

[0067] The first base gain (K1) is a value (K1(f3)) based on the carrier frequency (f3) set in the region (E3) encompassing the operating point (P1) (=point (A)), and the second base gain (K2) is a value (K2(f3)) based on the carrier frequency (f3) set in the region (E3) encompassing the look-ahead operating point (P2) (=point (A)), but K1(f3) and K2(f3) are the same value. The feedback gain (K), which is the output (min[K1,K2]) of the selection unit 357, is K(f3).

[0068] At time t0, the target torque (T * When the torque target value switches from a low torque target value to a high torque target value, the electric vehicle starts accelerating. At this time, the operating point (P1) (Figure 4) starts moving from point (A) to point (B), and the final torque command value (Tmf *) and rotational speed (N) begin to increase. At this time, the predictive torque command value (Tmf * LA ) is the final torque command value (Tmf * Maintain a value higher than ) and the final torque command value (Tmf * ) rises at the same rate of increase, and the number of pre-read rotations (N LA The ) also maintains a value higher than the rotational speed (N) and increases at the same rate of increase as the rotational speed (N). Therefore, the look-ahead operating point (P2) moves from point (A) to point (B) ahead of the operating point (P1) (Figure 4).

[0069] At time t1, the final torque command value (Tmf * When the high torque target value is reached and becomes constant, the look-ahead torque command value (Tmf * LA ) switches from a torque higher than the high torque target value to the high torque target value and becomes constant. Also, the final torque command value (Tmf) remains constant even after time t1. * ) maintains a high torque command value, so the predictive rotational speed (N LA ) and rotational speed (N) continue to increase.

[0070] At time t2, the number of look-ahead rotations (N LA When the signal reaches N2, the look-ahead operating point (P2) moves out of region (E3) and into region (E5). Therefore, the carrier frequency (f) extracted by the second map 354B (MAP2) switches from the value set in region (E3) (f3) to the value set in region (E5) (f4). As a result, the second base gain (K2) switches from K2(f3) to K2(f4), which has a higher value than K2(f3). Meanwhile, at time t2, the feedback gain (K) remains at K(f3).

[0071] At time t3, when the rotational speed (N) reaches N2, the operating point (P1) moves out of region (E3) and enters region (E5) (Figure 4). Therefore, the carrier frequency (f) extracted by the first map 354A (MAP1) switches from the value set in region (E3) (f3) to the value set in region (E5) (f4). As a result, the first base gain (K1) rises from K1(f3) to K1(f4), which is a higher value than K1(f3), at a predetermined rate of increase. At this time, the feedback gain (K) also rises from K(f3) to K(f4) in accordance with the rise in K1. Note that K1(f4) and K2(f4) are the same value.

[0072] Here, at time t3, if the first base gain (K1) switches in a step function manner from K1(f3) to K1(f4) as shown by the dashed line, the feedback gain (K) also switches in a step function manner from K1(f3) to K1(f4). In this case, the feedback control amount (the third torque command value (Tm3) shown in Figure 2) * The )) changes abruptly, causing fluctuations in acceleration. However, by increasing the first base gain (K1) and the feedback gain (K) at a predetermined rate of increase, as in this embodiment, the fluctuation of the feedback gain (K) becomes smooth, and fluctuations in acceleration can be suppressed.

[0073] When the operating point (P1) reaches point (B) at time t4, the target torque (T * The final torque command value (Tmf) is set to a predetermined negative torque target value lower than zero, and deceleration of the electric vehicle begins. * ) and rotational speed (N) begin to decrease, but the predictive torque command value (Tmf * LA ) is the final torque command value (Tmf * Maintain a value lower than ) and the final torque command value (Tmf * ) descends at the same rate of decline, and the number of pre-read rotations (N LA) also maintains a value lower than the rotational speed (N) and decreases at the same rate of decrease as the rotational speed (N). Just before time t4, the predictive operating point (P2) is located on the higher rotational speed side than point (B), but when time t4 is reached, it moves toward point (C) ahead of the operating point (P1).

[0074] At time t5, when the final torque command value (Tmf * ) reaches the negative torque target value and becomes constant, the predictive torque command value (Tmf * LA ) switches from a torque lower than the negative torque target value to the negative torque target value and becomes constant. Also, after time t5, since the final torque command value (Tmf * ) maintains the negative torque command value, the predictive rotational speed (N LA ) and the rotational speed (N) continue to decrease.

[0075] At time t6, when the predictive rotational speed (N LA ) becomes lower than N2, the predictive operating point (P2) exits region (E5) and enters region (E3). Therefore, the carrier frequency (f) extracted by the second map 354B (MAP2) switches from the value (f4) set in region (E5) to the value (f3) set in region (E3). As a result, the second base gain (K2) decreases from K2(f4) to K2(f3) at a predetermined rate of decrease, but the rate of decrease is set so that the time from K2(f4) to K2(f3) is less than or equal to the predictive time (Δt).

[0076] At time t7, when the rotational speed (N) becomes lower than N2, the operating point (P1) exits region (E5) and enters region (E3) (Fig. 4). Therefore, the carrier frequency (f) extracted by the first map 354A (MAP1) switches from the value (f4) set in region (E5) to the value (f3) set in region (E3). As a result, the first base gain (K1) switches from K1(f4) to K1(f3).

[0077] Between time t6 and time t7, the second base gain (K2) monotonically decreases from K2(f4), while the second base gain (K1) maintains K1(f4) (= K2(f4)). As a result, the feedback gain (K) also decreases from K(f4) as K2 decreases and reaches K(f3) before time t7.

[0078] Here, at time t6, when the second base gain (K2) stepwise switches from K2(f4) to K2(f3) as shown by the dashed line, the feedback gain (K) also stepwise switches from K1(f4) to K1(f3). In this case as well, fluctuations in acceleration occur as described above. However, by decreasing the second base gain (K2) and the feedback gain (K) at a predetermined decreasing rate as in this embodiment, smooth fluctuations in the feedback gain (K) are achieved, and fluctuations in acceleration can be suppressed.

[0079] At time t8, when the operating point (P1) reaches point (C), the target torque (T * ) switches from the negative torque target value to the low torque target value. As a result, the final torque command value (Tmf * ) increases from the negative torque target value toward the low torque target value, and the predictive torque command value (Tmf * LA ) also maintains a state higher than the final torque command value (Tmf * ) and increases at the same increasing rate as the final torque command value (Tmf * ). Also, the rotational speed (N) becomes constant, and the predictive rotational speed (N LA ) coincides with the rotational speed (N). Therefore, at time t8, the operating point (P1) moves from point (C) toward point (D), but the predictive operating point (P2) moves toward point (D) ahead of the operating point (P2).

[0080] At time t9, when the final torque command value (Tmf * ) reaches the low torque target value, the operating point (P1) reaches point (D). At this time, the predictive torque command value (Tmf * LA) switches from a value higher than the low torque target value to the low torque command value.

[0081] [Time chart when drive wheels 8a and 8b lock up during deceleration] Figure 8 is a time chart of the control system for the electric vehicle of this embodiment, showing the case where the drive wheels 8a and 8b lock during deceleration. The time chart shown in Figure 8 is the same as the time chart shown in Figure 7 from time t0 to time t4.

[0082] If, at time t41 after time t4, the rotational speed (N) suddenly drops to zero due to the locking of the drive wheels 8a and 8b, the look-ahead torque command value (Tmf * LA ) and lookahead rotation count (N LA ) becomes impossible to calculate.

[0083] In this case, the first base gain (K1) decreases stepwise from K1(f4) to K1(f3), while the second base gain (K2) decreases from K2(f4) to K2(f3) at a predetermined rate of decrease.

[0084] Therefore, the feedback gain (K) changes in a step function manner from K(f4) to K(f3), similar to K1. In this case, acceleration fluctuations may occur for the reasons mentioned above, but the control system prioritizes the stability of the feedback control, as described later.

[0085] [Feedback gain and carrier frequency] Figure 9 shows a characteristic curve (gain map) representing the conditions under which both disturbance responsiveness and stability of feedback control can be achieved in a coordinate space with the feedback gain (K) and carrier frequency (f) as axes, and the trajectory of the operating point in the coordinate space controlled by this embodiment.

[0086] The characteristic curve (L) shown in Figure 9 is similar to the maps of the first base gain setting unit 355A and the second base gain setting unit 355B shown in Figure 3.

[0087] Normally, a higher carrier frequency increases the system's processing speed, thus reducing the dead time in the output current response (the delay time from issuing a predetermined current command until the current actually rises) compared to a lower carrier frequency. This allows the stability of the feedback control to be maintained even with a large feedback gain (K). However, a lower carrier frequency increases the aforementioned dead time in the current response, making it impossible to maintain the stability of the feedback control without setting a low feedback gain (K).

[0088] Conventionally, as shown by the dashed line, the feedback gain was fixed at a low value to match the carrier frequency in order to ensure stable control even at the lowest carrier frequency used in the system. However, when the carrier frequency is increased while the feedback gain is fixed at a low value, although the stability of the feedback control can be maintained, the disturbance response (tracking ability) decreases to a level lower than the performance expected for that carrier frequency.

[0089] Therefore, in this embodiment, a feedback gain (K) (first base gain, second base gain) is set that can achieve both the stability of feedback control and disturbance responsiveness (tracking ability) according to the carrier frequency (f), and this is represented by the characteristic curve (L) shown in Figure 9.

[0090] In the coordinate space shown in Figure 9, the region below the characteristic curve (L) maintains the stability of the feedback control, but the performance in terms of disturbance response deteriorates as the region moves away from the characteristic region (L). Conversely, the region above the characteristic curve (L) in the coordinate space shown in Figure 9 is a region where the stability of the feedback control is insufficient.

[0091] For example, as shown in Figure 9, the carrier frequency is f α , Feedback gain (K(f α A point (α) on the characteristic curve (L) where )) and the carrier frequency f β (f α <f β ), feedback gain (K(f β))(K(f α ) <K(f β Consider the case where control is performed to switch the operating point between a point (β) on the characteristic curve (L) where )) is true and .

[0092] In this embodiment, when moving the operating point from point (α) to point (β), the operating point is moved in the horizontal direction f α f β Move to the step function, and then use the first base gain (K1) to move K(f) in the vertical direction. α ) from K(f β It is being moved to a predetermined rate of increase.

[0093] Furthermore, when moving the operating point from point (β) to point (α), the first base gain (K1) is used to move K(f) in the vertical axis direction. β ) from K(f α Move to a predetermined decrease rate, and then move the operating point in the horizontal direction f β f α The operating point is moved in a step function manner up to this point. As described above, even when the operating point is changed, the feedback gain (K) and carrier frequency (f) are controlled so that the operating point does not move above the characteristic curve (L).

[0094] Furthermore, as shown in Figure 8, if the drive wheels 8a and 8b lock during deceleration and the second base gain (K2) cannot be obtained, the carrier frequency (f) is set to f β f α The gain is reduced stepwise, and the value of the first base gain (K1) is used to set the gain to K(f β ) from K(f α By decreasing it stepwise, the operating point is moved stepwise from point (α) to point (β). This allows the operating point to move without passing through a region at least above the characteristic curve (L), thus maintaining the stability of the feedback control while tolerating fluctuations in acceleration.

[0095] [Effects of this embodiment] The control method for the electric vehicle of this embodiment is an inverse model (Gp(s)) of the vehicle model (Gp(s)) which models the power transmission system 7 of the electric vehicle that transmits the driving force of the drive motor 5 to the drive wheels 8a and 8b. -1 ) Based on the driver's request, the target torque (T * ) is subjected to vibration damping treatment to obtain the first torque command value (Tm1 * ) generates the first torque command value (Tm1 * The difference between the estimated value (ωm^) of the rotational speed (N) of the drive motor 5 obtained by inputting ) into the vehicle model (Gp(s)) and the detected value (ωm) of the rotational speed (N) of the drive motor 5 is used for the inverse model (Gp(s)). -1 ) and a bandpass filter (H(s)) whose center frequency is the resonant frequency of the drive force transmission system 7, and the value obtained by inputting this into a filter (control block 33) represented by the product of these two values ​​(second torque command value (Tm2) * )) is multiplied by a predetermined feedback gain (K) to obtain the second torque command value (third torque command value (Tm3 * )) generates the first torque command value (Tm1 * ) and the second torque command value (third torque command value (Tm3 * The final torque command value (Tmf) is obtained by summing the )) * ) generates the final torque command value (Tmf * When converting the rotational speed (N) of the drive motor 5 into a PWM signal for controlling the drive motor 5, the rotational speed (N) of the drive motor 5 and the final torque command value (Tmf) are used. * A control method for an electric vehicle in which a coordinate space centered on and is divided into multiple regions (E1-E7), and setting values ​​(f1-f6) for the carrier frequency (f) of the PWM signal are individually set corresponding to the regions (E1-E7), and the carrier frequency (f) is set to the setting value (f1-f6) related to the region (E1-E7) that includes the operating point (P1) of the drive motor 5 in the coordinate space, wherein the feedback gain (K) is set based on the magnitude of the setting value (f1-f6) related to the region (E1-E7) that includes the operating point (P1).

[0096] By the method described above, a feedback gain (K) is set that balances the stability of the feedback control with the responsiveness (followability) of disturbances, depending on the carrier frequency (f), thereby maintaining the stability of the motor control and good responsiveness. More specifically, when the carrier frequency (f) is high, the feedback gain (K) in vibration damping control is set to be large, and when the carrier frequency (f) is low, the feedback gain (K) is set to be small, thereby suppressing the effect of dead time on control stability. In the drive motor 5, the carrier frequency (f) is varied according to the rotational speed (N) and torque, taking into account control followability and semiconductor losses. For example, it is set higher than the normal value during high-speed driving and lowered in situations where motor lock may occur. In this embodiment, the feedback gain (K) is calculated based on the variable carrier frequency (f). This takes into account control followability and semiconductor losses, suppresses abrupt changes in the input amount of the feedback control, and suppresses fluctuations in the acceleration of the electric vehicle.

[0097] In this embodiment, when a plurality of regions (E1-E7) include a pair of adjacent regions (e.g., region (E3), region (E5)), and the set value includes a first set value (f3) set in one of the pair of regions (region (E3)) and a second set value (f4) set in the other of the pair of regions (region (E5)) that is higher than the first set value (f3), when the operating point (P1) moves from one of the pair of regions (region (E3)) to the other (region (E5)), The feedback gain (K) is increased at a predetermined rate from a value corresponding to the first setpoint (f3) (K(f3)) to a value corresponding to the second setpoint (f4) (K(f4)), and when the operating point (P1) moves from one of a pair of regions (region (E5)) to the other (region (E3)), the feedback gain (K) is decreased at a predetermined rate from a value corresponding to the second setpoint (f4) (K(f4)) to a value corresponding to the first setpoint (f3) (K(f3)).

[0098] Using the above method, for example, if the feedback gain (K) switches in a step function manner from K1(f3) to K1(f4), or from K1(f3) to K1(f4), the feedback control amount (the third torque command value (Tm3) shown in Figure 2) is used. * The carrier frequency changes rapidly, causing fluctuations in acceleration. However, by increasing the feedback gain (K) at a predetermined increase rate and decreasing it at a predetermined decrease rate, as in this embodiment, the fluctuation of the feedback gain (K) becomes smooth, and fluctuations in acceleration can be suppressed. Furthermore, by using the above method, the increase rate at which the feedback gain changes from a low value to a high value and the decrease rate at which it changes from a high value to a low value in vibration damping control are calculated separately, thereby ensuring greater control stability. As a result, while conventionally the gain was set under conditions where the carrier frequency was low in order to prioritize control stability, by setting an appropriate gain even under conditions where the carrier frequency is high, response disturbance can be improved.

[0099] In this embodiment, when a plurality of regions (E1-E7) include a pair of adjacent regions (e.g., region (E3), region (E5)), and the set value (f1-f6) includes a first set value (f3) set in one of the pair of regions (region (E3)) and a second set value (f4) set in the other of the pair of regions (region (E5)) that is higher than the first set value (f3), the final torque command value (Tmf * Based on the change in ), the look-ahead torque command value (Tmf) after a predetermined time (look-ahead time: Δt) has elapsed is used. * LA ) is estimated, and based on the change in the rotational speed (N) of the drive motor 5, the look-ahead rotational speed (N) after a predetermined time (look-ahead time: Δt) has elapsed for the drive motor 5 is estimated. LA The system estimates the torque, sets the first base gain (K1) based on the setting value set in the region encompassing the operating point (P1), and predicts the torque command value (Tmf * LA ) and the number of pre-read rotations (N LAThe second base gain (K2) is set based on the setting value set in the region encompassing the look-ahead operating point (P2) in the coordinate space including ), and when the operating point (P1) moves from one of the pair of regions (region (E3)) to the other (region (E5)), the first base gain (K1) is increased at a predetermined increase rate from the value corresponding to the first setting value (f3) (K1(f3)) to the value corresponding to the second setting value (f4) (K1(f4)), when the operating point (P1) moves from the other of the pair of regions (region (E5)) to the other (region (E3)), the first base gain (K1) is switched from the value corresponding to the second setting value (f4) (K1(f4)) to the value corresponding to the first setting value (K1(f3)), and when the look-ahead operating point (P2) moves from one of the pair of regions (region (E3)) to the other (region (E5)) prior to the operating point (P1), the second base gain (K2) is set to the first setting value ( The value corresponding to f3) (K2(f3)) is switched to the value corresponding to the second setpoint (f4) (K2(f4)), and when the look-ahead operating point (P2) moves from one of the pair of regions (region (E5)) to the other (region (E3)) prior to the operating point (P1), the second base gain (K2) is reduced at a predetermined reduction rate from the value corresponding to the second setpoint (f4) (K2(f4)) to the value corresponding to the first setpoint (f3) (K2(f3)), and the magnitude of the reduction rate is set so that the second base gain (K2) reaches the value corresponding to the first setpoint (f3) (K2(f3)) before a predetermined time (look-ahead time: Δt) has elapsed since the look-ahead operating point (P2) moved from the other (region (E5)) to the other (region (E3)), and the current first base gain (K1) and second base gain (K2) are compared and the lower value is set as the feedback gain (K).

[0100] By the above method, the feedback gain (K) begins to decrease from the value corresponding to the second setpoint (f4) (K(f4)) to the value corresponding to the first setpoint (f3) (K(f3)) before the operating point (P1) moves from the other of the pair of regions (region (E5)) to the other (region (E3)). Immediately before the operating point (P1) enters one of the pair of regions (region (E3)), the feedback gain (K) is at the value corresponding to the first setpoint (f3) (K(f3)), thus suppressing unnecessary fluctuations in the feedback operation amount.

[0101] In this embodiment, when the rotational speed (N) of the drive motor 5 included in the operating point (P1) is lower than a predetermined threshold (e.g., N2) when increasing the first base gain (K1) at a predetermined rate of increase, the magnitude of the rate of increase is set to be higher than the magnitude of the rate of increase set when the operating point (P1) moves from one of a pair of regions (e.g., region (E5), region (E5)) to the other (region (E6)) and the rotational speed (N) of the drive motor 5 included in the operating point (P1) is equal to or greater than the threshold (e.g., N2).

[0102] The above method makes it possible to efficiently eliminate unwanted vibrations such as torque ripple and powertrain resonance that appear in the low rotational speed range below a predetermined threshold.

[0103] In this embodiment, the reduction rate is calculated by subtracting the value of the second base gain (K2) corresponding to the first base gain (K2) (K2(f3)) from the value of the second base gain (K2) corresponding to the second base gain (K2) corresponding to the second base gain (K2(f4)) corresponding to the second base gain (f4) by a predetermined time (look-ahead time: Δt).

[0104] Using the method described above, the rate of decrease can be calculated in a simple manner.

[0105] In this embodiment, when the electric vehicle decelerates, the drive wheels 8a and 8b lock, thereby increasing the predictive torque command value (Tmf * LA ) and lookahead rotation count (N LA When the value cannot be estimated, the timing of switching the feedback gain (K) is synchronized with the timing of switching the carrier frequency (f).

[0106] In this embodiment, the low-pass filter 3523 is used to obtain the final torque command value (Tmf *The look-ahead component of ) is calculated, and the look-ahead component of rotational speed (N) is calculated using the low-pass filter 3533. Therefore, if the drive wheels 8a and 8b lock up, these look-ahead components cannot be calculated. However, the above method allows for fluctuations in acceleration while maintaining the stability of the feedback control.

[0107] The control system for the electric vehicle of this embodiment is an inverse model (Gp(s)) of the vehicle model (Gp(s)) which models the power transmission system 7 of the electric vehicle that transmits the driving force of the drive motor 5 to the drive wheels 8a and 8b. -1 ) Based on the driver's request, the target torque (T * ) is subjected to vibration damping treatment to obtain the first torque command value (Tm1 * A motor torque setting unit 2 generates a first torque command value (Tm1 * The difference between the estimated value (ωm^) of the rotational speed (N) of the drive motor 5 obtained by inputting ) into the vehicle model (Gp(s)) and the detected value (ωm) of the rotational speed (N) of the drive motor 5 is used for the inverse model (Gp(s)). -1 ) and a bandpass filter (H(s)) whose center frequency is the resonant frequency of the drive force transmission system 7, and the value obtained by inputting this into a filter (control block 33) represented by the product of these two values ​​(second torque command value (Tm2) * )) is multiplied by a predetermined feedback gain (K) to obtain the second torque command value (third torque command value (Tm3 * A gain multiplication unit 35 generates the first torque command value (Tm1 * ) and the second torque command value (third torque command value (Tm3 * The final torque command value (Tmf) is obtained by summing the )) * ) generates the final torque command value (Tmf * A PWM signal generation unit (motor torque control unit 4) converts the rotational speed (N) of the drive motor 5 into a PWM signal for controlling the drive motor 5, and the final torque command value (Tmf *A control system for an electric vehicle, comprising: a carrier frequency setting unit (motor torque control unit 4) which includes information on the set values ​​(f1-f6) of the carrier frequency (f) of the PWM signal, which is set individually for each region (E1-E7) and divides the coordinate space with the axis into multiple regions (E1-E7), and sets the carrier frequency (f) to the set value related to the region in the coordinate space that includes the operating point (P1) of the drive motor 5, wherein the gain multiplication unit 35 sets the feedback gain (K) based on the magnitude of the set value related to the region that includes the operating point (P1).

[0108] With the above configuration, a feedback gain (K) is set that balances the stability of the feedback control with the responsiveness (tracking ability) of disturbances, depending on the carrier frequency (f), thereby maintaining the stability of the motor control and good responsiveness. In the drive motor 5, the carrier frequency (f) is varied according to the rotational speed (N) and torque, taking into account the control tracking ability and semiconductor losses. For example, it is set higher than the normal value during high-speed driving and lowered in situations where the motor might lock up. In this embodiment, the feedback gain (K) is calculated based on the variable carrier frequency (f). This takes into account the control tracking ability and semiconductor losses, suppresses abrupt changes in the feedback control input, and suppresses fluctuations in the acceleration of the electric vehicle.

[0109] Although embodiments of the present invention have been described above, these embodiments represent only a part of the application examples of the present invention, and are not intended to limit the technical scope of the present invention to the specific configurations of the above embodiments. Furthermore, the above embodiments can be combined as appropriate. [Explanation of Symbols]

[0110] 2 Motor torque setting unit, 3 Vibration damping control unit, 4 Motor torque control unit, 5 Drive motor, 35 Gain Multiplication Section

Claims

1. Based on an inverse model of a vehicle model that models the power transmission system of an electric vehicle that transmits the driving force of the drive motor to the drive wheels, the target torque generated based on the driver's request is subjected to vibration damping to generate a first torque command value. The difference between the estimated rotational speed of the drive motor obtained by inputting the first torque command value into the vehicle model and the detected rotational speed of the drive motor is input into a filter represented by the product of the inverse model and a bandpass filter whose center frequency is the resonant frequency of the drive force transmission system, and the value obtained is multiplied by a predetermined feedback gain to generate a second torque command value. In a case where a final torque command value is generated by adding the first torque command value and the second torque command value, and the final torque command value is converted into a PWM signal for controlling the drive motor, The coordinate space, with the rotational speed of the drive motor and the final torque command value as axes, is divided into multiple regions, and the carrier frequency setting value of the PWM signal is individually set corresponding to each region. A control method for an electric vehicle, wherein the carrier frequency is set to the set value relating to the region in the coordinate space that includes the operating point of the drive motor, A control method for an electric vehicle, which sets the feedback gain based on the magnitude of the set value relating to the region that includes the operating point.

2. A plurality of the aforementioned regions include a pair of the aforementioned regions that are adjacent to each other, When the setting value includes a first setting value set in one of the pair of regions and a second setting value set in the other of the pair of regions that is higher than the first setting value, When the operating point moves from one of the pair of regions to the other, the feedback gain is increased at a predetermined rate from a value corresponding to the first set value to a relative value corresponding to the second set value. The method for controlling an electric vehicle according to claim 1, wherein when the operating point moves from one of a pair of regions to the other, the feedback gain is reduced at a predetermined reduction rate from a value corresponding to the second set value to a value corresponding to the first set value.

3. A plurality of the aforementioned regions include a pair of the aforementioned regions that are adjacent to each other, When the setting value includes a first setting value set in one of the pair of regions and a second setting value set in the other of the pair of regions that is higher than the first setting value, Based on the change in the final torque command value, the look-ahead torque command value after a predetermined time has elapsed is estimated. Based on the change in the rotational speed of the drive motor, the predictive rotational speed of the drive motor after the predetermined time has elapsed is estimated. A first base gain is set based on the setting value set in the region encompassing the operating point. A second base gain is set based on the setting value set in the region that includes the look-ahead torque command value and the look-ahead rotational speed, and the region that includes the look-ahead operating point in the coordinate space. When the operating point moves from one of the pair of regions to the other, the first base gain is increased at a predetermined rate from a value corresponding to the first set value to a value corresponding to the second set value, and when the operating point moves from the other of the pair of regions to the other, the first base gain is switched from a value corresponding to the second set value to a value corresponding to the first set value. When the look-ahead operating point moves from one of the pair of regions to the other prior to the operating point, the second base gain is switched from a value corresponding to the first set value to a value corresponding to the second set value, and when the look-ahead operating point moves from the other of the pair of regions to the one prior to the operating point, the second base gain is reduced at a predetermined reduction rate from a value corresponding to the second set value to a value corresponding to the first set value. The magnitude of the reduction rate is set such that the second base gain reaches a value corresponding to the first set value before the predetermined time elapses after the look-ahead operating point moves from one of the pair of regions to the other. A method for controlling an electric vehicle according to claim 1, wherein the current first base gain and second base gain are compared and the lower value is set as the feedback gain.

4. A method for controlling an electric vehicle according to claim 3, wherein the magnitude of the increase rate when the rotational speed of the drive motor included in the operating point is lower than a predetermined threshold when the first base gain is increased by the increase rate is set to be higher than the magnitude of the increase rate set when the operating point moves from one of a pair of regions to the other and the rotational speed of the drive motor included in the operating point is equal to or greater than the threshold.

5. A control method for an electric vehicle according to claim 3, wherein the reduction rate is calculated by dividing the difference obtained by subtracting the value of the second base gain corresponding to the first setting value from the value of the second base gain corresponding to the second setting value by the predetermined time.

6. When the drive wheels lock up during deceleration of an electric vehicle, making it impossible to estimate the predictive torque command value and the predictive rotational speed, The control method for an electric vehicle according to claim 3, wherein the timing of switching the feedback gain is synchronized with the timing of switching the carrier frequency.

7. A motor torque setting unit generates a first torque command value by applying vibration damping processing to a target torque generated based on the driver's request, based on an inverse model of a vehicle model that models the drive force transmission system of an electric vehicle that transmits the driving force of the drive motor to the drive wheels, and A gain multiplication unit generates a second torque command value by multiplying the difference between the estimated rotational speed of the drive motor obtained by inputting the first torque command value into the vehicle model and the detected rotational speed of the drive motor by a predetermined feedback gain, which is input into a filter represented by the product of the inverse model and a bandpass filter whose center frequency is the resonant frequency of the drive force transmission system. A PWM signal generation unit generates a final torque command value by adding the first torque command value and the second torque command value, and converts the final torque command value into a PWM signal for controlling the drive motor. A control system for an electric vehicle, comprising: a carrier frequency setting unit which includes information on a set value of the carrier frequency of the PWM signal, which is set individually for each region, and which divides the coordinate space with the rotational speed of the drive motor and the final torque command value as axes into a plurality of regions, and sets the carrier frequency to the set value for the region in the coordinate space that includes the operating point of the drive motor; The aforementioned gain multiplication unit is A control system for an electric vehicle that sets the feedback gain based on the magnitude of the set value relating to the region that includes the operating point.

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