Vibration control device, inverter and vibration control method

Abstract

To provide a vibration control device that determines an uphill running state and suppresses vibrations during uphill running.SOLUTION: An FF compensator 1 inputs a torque command input Tm_in and outputs a FF compensated torque command Tm_ff. A norm speed estimator 3 outputs an estimated motor angular velocity value ωm_est based on the FF compensated torque command Tm_ff. An FB compensator 2 inputs the estimated motor angular velocity value ωm_est and a detected motor angular speed value ωm_det and outputs an FB compensated torque command Tm_fb. An FB gain multiplier multiplies the FB compensated torque command Tm_fb by the FB gain. An adder 5 adds the product of the FB compensation torque command Tm_fb and the FB gain to the FF compensated torque command Tm_ff and outputs the resulting value as torque command output. When a deviation between the estimated motor angular speed value ωm_est and the detected motor angular speed value ωm_det is larger than a threshold value, the FB gain multiplier sets the FB higher than otherwise.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to vibration control for suppressing axial torsional vibration of an electric vehicle.

Background Art

[0002] An electric vehicle converts DC power of a battery into AC power by an inverter and supplies it to a motor, and operates by the driving force of the motor.

[0003] An inverter having a vibration suppression function includes at least the following (1) to (3). (1) A main circuit composed of semiconductor switching elements that convert DC power into AC power. (2) A vibration control device that suppresses vehicle vibration by adjusting an external torque command input. (3) An inverter controller that generates an on / off signal of a semiconductor switching element of the main circuit based on a torque command output output by the vibration control device to control the torque of the motor.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] FIG. 1 shows an example of a conventional vibration control device applied to an electric vehicle. The vibration control device includes an FF compensator 1 that suppresses vibration caused by a torque command, an FB compensator 2 that suppresses vibration caused by an external disturbance, and a reference speed estimator 3 for independently operating the FF compensator 1 and the FB compensator 2. For FB compensation, an FB gain K for weighting the vibration suppression effect is multiplied by the output of the FB compensator 2 by an FB gain multiplier 4. As prior art of this control method, Patent Document 1 is disclosed.

[0006] FIG. 2 is FIG. 4 (block diagram showing vibration control arithmetic processing) of Patent Document 1. Each configuration of FIG. 1 in this specification and FIG. 4 of Patent Document 1 corresponds as shown in the following table.

[0007] [Table 1]

[0008] As factors causing vibration during uphill travel of an electric vehicle, there are motor torque ripple and torsional vibration of the drive shaft. In particular, since vibration tends to be amplified in the frequency band where the two coincide, it is effective to increase the FB gain of FB compensation as a countermeasure.

[0009] On the other hand, a resolver is representative of motor angle detectors. Since the resolver has an inherent error and the error component appears as vibration control FB compensation torque, it has been found that when the FB gain is increased, the sound and vibration performance of the electric vehicle deteriorates due to the error torque.

[0010] As a specific method of increasing the FB gain during the above-mentioned uphill travel, Claim 4 of Patent Document 1 discloses a method of detecting the gradient of the road surface and changing the FB gain based on the gradient detection value. However, this method requires complicated gradient detection means.

[0011] From the above, in a vibration control device, it is an issue to determine the uphill travel state and suppress vibration during uphill travel. [Means for Solving the Problem]

[0012] The present invention has been devised in view of the above-described conventional problems. One aspect thereof is a vibration control device for an electric vehicle that controls an inverter based on a torque command output to drive a motor, comprising: an FF compensator that inputs a torque command input and performs a feed-forward calculation for suppressing vibration of a torque transmission system of the electric vehicle to output an FF compensation torque command; a reference speed estimator that outputs an estimated motor angular velocity based on the FF compensation torque command; an FB compensator that inputs the estimated motor angular velocity and a detected motor angular velocity and performs a feedback calculation for suppressing vibration of the torque transmission system of the electric vehicle to output an FB compensation torque command; an FB gain multiplier that multiplies the FB compensation torque command by an FB gain; and an adder that adds a value obtained by multiplying the FB compensation torque command by the FB gain and the FF compensation torque command and outputs the result as the torque command output. The FB gain multiplier is characterized in that when the deviation between the estimated motor angular velocity and the detected motor angular velocity is greater than a threshold value, the FB gain is set higher than when the deviation between the estimated motor angular velocity and the detected motor angular velocity is less than or equal to the threshold value.

[0013] Also, as one aspect, the FB gain multiplier includes a first FB gain multiplier that multiplies the FB compensation torque command by a first FB gain, and a second FB gain multiplier that multiplies the FB compensation torque command by a second FB gain higher than the first FB gain. When the deviation between the estimated motor angular velocity and the detected motor angular velocity is less than or equal to the threshold value, it is determined that the vehicle is in a normal driving state. When the deviation between the estimated motor angular velocity and the detected motor angular velocity is greater than the threshold value, it is determined that the vehicle is in a climbing driving state. A climbing driving state determination unit that outputs a driving state determination signal; and a switch that outputs the output of the first FB gain multiplier to the adder when the driving state determination signal indicates the normal driving state, and outputs the output of the second FB gain multiplier to the adder when the driving state determination signal indicates the climbing driving state.

[0014] Also, an inverter, comprising: the vibration control device; the main circuit of the inverter; and an inverter controller that generates an on / off signal of a semiconductor switching element of the main circuit based on the torque command output output by the vibration control device to control the torque of the motor.

Effect of the Invention

[0015] According to the present invention, in the vibration control device, it is possible to determine the uphill running state and suppress the vibration during uphill running.

Brief Description of the Drawings

[0016]

Figure 1

Figure 2

Figure 3

Embodiments for Carrying Out the Invention

[0017] Hereinafter, embodiments of the vibration control device in the present invention will be described in detail with reference to FIG. 3.

[0018] [Embodiment] The vibration control device of the present embodiment is applied to an electric vehicle that drives a motor by controlling an inverter based on a torque command output. The electric vehicle is applicable not only to electric vehicles but also to hybrid vehicles and fuel cell vehicles. As described in the background art, the inverter includes (1) a main circuit, (2) a vibration control device, and (3) an inverter controller.

[0019] FIG. 3 is a block diagram of the vibration control device in the present embodiment. The vibration control device includes an FF compensator 1, an FB compensator 2, a reference speed estimator 3, first and second FB gain multipliers 4a and 4b, an adder 5, an uphill running state determination unit 6, and a switch 7.

[0020] The FF compensator 1 has a transfer characteristic of Gm(s) / Gp(s). Gp(s) is a vehicle model that represents the transfer characteristic between the torque input to the vehicle and the motor speed, and Gm(s) is an ideal model that represents the transfer characteristic between the torque input to the vehicle and the response target of the motor speed. The FF compensator 1 is a filter that reduces the natural vibration frequency component (vibration) of the vehicle's torque transmission system. It receives the torque command input Tm_in, performs a feed-forward operation, and outputs the FF compensation torque command Tm_ff.

[0021] The reference speed estimator 3 has a transfer characteristic of the vehicle model Gp(s). The reference speed estimator 3 outputs the estimated motor angular velocity ωm_est based on the FF compensation torque command Tm_ff.

[0022] The FB compensator 2 has a transfer characteristic of H(s) / Gp(s). H(s) has the characteristics of a band-pass filter whose center frequency coincides with the torsional resonance frequency of the vehicle's drive system.

[0023] The FB compensator 2 receives the estimated motor angular velocity ωm_est and the detected motor angular velocity ωm_det, calculates the deviation between the estimated motor angular velocity ωm_est and the detected motor angular velocity ωm_det, and performs a feedback operation through the transfer characteristic of H(s) / Gp(s) to suppress the vibration of the vehicle's torque transmission system, and outputs it as the FB compensation torque command Tm_fb.

[0024] The calculation methods of the vehicle model Gp(s), the ideal model Gm(s), and H(s) are conventionally known, so the detailed description of the calculation methods is omitted here.

[0025] The FB gain multiplier multiplies the FB compensation torque command Tm_fb by the FB gain. In this embodiment, the FB gain multiplier includes a first FB gain multiplier 4a and a second FB gain multiplier 4b.

[0026] The first FB gain multiplier 4a multiplies the FB compensation torque command Tm_fb by the first FB gain K1. The second FB gain multiplier 4b multiplies the FB compensation torque command Tm_fb by the second FB gain K2. The second FB gain K2 is set to a value higher than the first FB gain K1.

[0027] The uphill running state determination unit 6 determines whether it is in a normal running state or an uphill running state based on the estimated motor angular velocity ωm_est and the detected motor angular velocity ωm_det, and outputs it as a running state determination signal FB_Ena.

[0028] The switch 7 inputs the output of the first FB gain multiplier 4a and the output of the second FB gain multiplier 4b, and outputs the output of the first FB gain multiplier 4a when the running state determination signal FB_Ena indicates the normal running state, and outputs the output of the second FB gain multiplier 4b when the running state determination signal FB_Ena indicates the uphill running state.

[0029] That is, during normal running, vibration suppression control using the first FB gain K1 is performed, and during uphill running, vibration suppression control using the second FB gain K2, which is larger than the first FB gain K1 during normal running, is performed.

[0030] The adder 5 adds the FF compensation torque command Tm_ff and the output of the switch 7 (the output of the first FB gain multiplier 4a or the output of the second FB gain multiplier 4b) and outputs it as a torque command output.

[0031] The first and second FB gains K1 and K2 of the first and second FB gain multipliers 4a and 4b shown in FIG. 3 can be set between 0 and 1. By setting K1 and K2 = 1, the FB compensator 2 becomes an ideal state (ζ = 1). The first and second FB gains K1 and K2 are set so as to be able to compensate for the influence of the control operation time, the motor response delay, and the sensor signal processing time in consideration of the delay elements of the control system in the feedback loop.

[0032] In this embodiment, the running state is determined using the estimated motor angular velocity ωm_est and the detected motor angular velocity ωm_det.

[0033] The estimated motor angular velocity ωm_est is obtained by obtaining a standard speed based on the FF compensation torque command Tm_ff and the vehicle model specifications. The detected motor angular velocity ωm_det varies due to factors such as braking operations and running resistance in addition to the torque command. When driving uphill, the detected motor angular velocity ωm_det is affected by the gradient resistance and thus deviates from the estimated motor angular velocity ωm_est.

[0034] In this embodiment, the running state is determined using this characteristic. When the deviation (difference) between the estimated motor angular velocity ωm_est and the detected motor angular velocity ωm_det is within a predetermined threshold in the uphill running state determination unit 6, it is determined as the normal running state. When the deviation (difference) between the estimated motor angular velocity ωm_est and the detected motor angular velocity ωm_det exceeds the predetermined threshold, it is determined as the uphill running state and output as the running state determination signal FB_Ena.

[0035] The first FB gain multiplier 4a multiplies the FB compensation torque command Tm_fb by the first FB gain K1. The second FB gain multiplier 4b multiplies the FB compensation torque command Tm_fb by the second FB gain K2, which is set higher than the first FB gain K1.

[0036] Then, at the switch 7, when the running state determination signal FB_Ena indicates the normal running state, a value obtained by multiplying the FB compensation torque command Tm_fb by the first FB gain K1 is output. When the running state determination signal FB_Ena indicates the uphill running state, a value obtained by multiplying the FB compensation torque command Tm_fb by the second FB gain K2, which is set to a value higher than the first FB gain K1, is output.

[0037] That is, the FB gain multiplier sets the FB gain higher when the deviation between the estimated motor angular velocity ωm_est and the detected motor angular velocity ωm_det is greater than the threshold than when the deviation between the estimated motor angular velocity ωm_est and the detected motor angular velocity ωm_det is below the threshold.

[0038] By setting the second FB gain K2 used during uphill travel to a value higher than the first FB gain K1 used during normal travel, it is possible to suppress vibrations during uphill travel and improve the riding comfort.

[0039] In this embodiment, as shown in FIG. 3, a configuration including two first and second FB gain multipliers 4a, 4b and a switch 7 has been described. However, as shown in FIG. 1, there may be only one gain multiplier and the switch may be omitted. In that case, in the FB gain multiplier, when the deviation between the estimated motor angular velocity ωm_est and the detected motor angular velocity ωm_det is greater than the threshold value, the FB gain is set higher than when the deviation between the estimated motor angular velocity ωm_est and the detected motor angular velocity ωm_det is below the threshold value.

[0040] [Effect] As described above, according to this embodiment, it is possible to determine the uphill travel state, enhance the effectiveness of FB compensation, and suppress vibrations during uphill travel. Thereby, the riding comfort during uphill travel can be improved.

[0041] Also, in comparison with Patent Document 1, instead of using complicated gradient detection means, the uphill travel state is determined only by comparing the estimated motor angular velocity ωm_est and the detected motor angular velocity ωm_det used in vibration control. Therefore, the vibration control device can be miniaturized and cost-reduced.

[0042] As described above, in the present invention, although detailed description has been made only for the specific examples described, it is obvious to those skilled in the art that various modifications and corrections are possible within the scope of the technical idea of the present invention, and it is natural that such modifications and corrections belong to the scope of the claims.

Explanation of Reference Numerals

[0043] 1... FF compensator 2... FB compensator 3... Nominal speed estimator 4a... First FB gain multiplier 4b... Second FB gain multiplier 5... Adder 6…Climbing running state determination unit 7…Switch

Claims

1. A vibration control device for an electric vehicle that drives a motor by controlling an inverter based on a torque command output, an FF compensator that inputs a torque command input, performs a feedforward operation to suppress vibration of the torque transmission system of the electric vehicle, and outputs an FF compensation torque command; a reference speed estimator that outputs an estimated motor angular velocity based on the FF compensation torque command; an FB compensator that inputs the estimated motor angular velocity and the detected motor angular velocity, performs a feedback operation to suppress vibration of the torque transmission system of the electric vehicle, and outputs an FB compensation torque command; an FB gain multiplier that multiplies the FB compensation torque command by an FB gain; an adder that adds the value obtained by multiplying the FB compensation torque command by the FB gain and the FF compensation torque command and outputs the result as the torque command output; and is provided with, wherein the FB gain multiplier sets the FB gain higher when the deviation between the estimated motor angular velocity and the detected motor angular velocity is greater than a threshold value than when the deviation is less than or equal to the threshold value. A vibration control device characterized by this.

2. The FB gain multiplier is a first FB gain multiplier that multiplies the FB compensation torque command by a first FB gain and a second FB gain multiplier that multiplies the FB compensation torque command by a second FB gain higher than the first FB gain, a climbing driving state determination unit that determines that it is in a normal driving state when the deviation between the estimated motor angular velocity and the detected motor angular velocity is less than or equal to a threshold value, and determines that it is in a climbing driving state when the deviation between the estimated motor angular velocity and the detected motor angular velocity is greater than the threshold value, and outputs it as a driving state determination signal; a switch that outputs the output of the first FB gain multiplier to the adder when the driving state determination signal indicates the normal driving state, and outputs the output of the second FB gain multiplier to the adder when the driving state determination signal indicates the climbing driving state; The vibration control device according to claim 1, characterized by comprising.

3. The vibration control device according to claim 1 or 2, the main circuit of the inverter, An inverter characterized by comprising an inverter controller that generates an on / off signal of a semiconductor switching element of the main circuit based on the torque command output output by the vibration control device and controls the torque of the motor.

4. A vibration control method for a vibration control device of an electric vehicle that drives a motor by controlling an inverter based on a torque command output, an FF compensator inputs a torque command input and performs a feed-forward operation to suppress vibration of the torque transmission system of the electric vehicle, and outputs an FF compensation torque command, a reference speed estimator outputs an estimated motor angular velocity value based on the FF compensation torque command, an FB compensator inputs the estimated motor angular velocity value and the detected motor angular velocity value, performs a feedback operation to suppress vibration of the torque transmission system of the electric vehicle, and outputs an FB compensation torque command, an FB gain multiplier multiplies the FB compensation torque command by an FB gain, an adder adds the value obtained by multiplying the FB compensation torque command by the FB gain and the FF compensation torque command and outputs the result as the torque command output, wherein the FB gain multiplier sets the FB gain higher when the deviation between the estimated motor angular velocity value and the detected motor angular velocity value is greater than a threshold value than when the deviation is less than or equal to the threshold value.

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