Electric vehicle control method, and electric vehicle control device

Abstract

To provide electric vehicle control method and control device that can suppress vibration of a torque transmission system even when a torque command value is very small.SOLUTION: A feedback torque TFB is calculated on the basis of a rotational state (Nm) of a rotary electric machine 10, a torque command value (Tm1*) is corrected on the basis of the feedback torque TFB, and the rotary electric machine 10 is controlled according to the torque command value (Tm2*) after correction. A limit value Tlmt is set for an absolute value |TFB| of the feedback torque TFB, and the limit value Tlmt is changed according to an absolute value |Tm1*| of a basic torque command value Tm1* which is a torque command value before correction. When at least the absolute value |Tm1*| of the basic torque command value Tm1* can be deemed to be zero, change of the limit value Tlmt according to the absolute value |Tm1*| of the basic torque command value |Tm1*| is so made as to be slower compared to the case that the absolute value |Tm1*| of the basic torque command value Tm1* cannot be deemed to be zero.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] The present invention relates to a control method and a control device for an electric vehicle.

Background Art

[0002] Patent Document 1 discloses a motor control device that adds a first torque target value based on vehicle information and a second torque target value based on the rotational speed to calculate a torque command value for controlling a motor, and makes the sign of the first torque target value and the sign of the torque command value the same sign, and limits the torque command value according to the first torque target value.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In order to suppress vibration of a torque transmission system (such as a drive shaft) that transmits torque generated by a rotating electrical machine, an electric vehicle is known that calculates feedback torque based on the rotational state of the rotating electrical machine and corrects a torque command value based on this feedback torque. Further, since the torque transmission system includes a gear, when the positive and negative of the torque command value are reversed, noise (so-called rattling sound) due to backlash of the gear may occur. Therefore, when correcting the torque command value for vibration suppression, the feedback torque may be limited according to the magnitude of the torque command value so that the positive and negative of the torque command value do not reverse due to correction based on the feedback torque.

[0005] On the one hand, when the feedback torque is restricted according to the magnitude of the torque command value in this way, when the torque command value is small, the feedback torque is also restricted to a small value, making it difficult to obtain a vibration damping effect. Specifically, in a scene where the magnitude of the torque command value is substantially zero, the magnitude of the feedback torque is also restricted to substantially zero, so the correction (vibration damping) by the feedback torque is substantially ineffective. For this reason, when vibration occurs or remains in the torque transmission system when the magnitude of the torque command value becomes substantially zero, the vibration will continue thereafter.

[0006] For example, when the accelerator is released or the shift position is switched from the D (Drive) range to the N (Neutral) range, the torque command value becomes almost instantaneously zero. On the other hand, since the rotation of the rotating electrical machine (motor) remains, vibration may occur in the torque transmission system due to the torque input from the rotating electrical machine. At this time, if the feedback torque for vibration damping is also restricted to zero in response to the torque command value becoming zero, the vibration of the torque transmission system will not be reduced and will continue thereafter.

[0007] An object of the present invention is to provide a control method and a control device for an electric vehicle that can suppress vibration of a torque transmission system even when the torque command value is extremely small.

Means for Solving the Problems

[0008] One aspect of the present invention is a control method for an electric vehicle that calculates a feedback torque based on the rotational state of a rotating electrical machine, corrects a torque command value based on the feedback torque, and controls the rotating electrical machine according to the corrected torque command value. In this control method for an electric vehicle, a limit value is set for the absolute value of the feedback torque, and the limit value is changed according to the absolute value of the basic torque command value, which is the torque command value before correction by the feedback torque. And when at least the absolute value of the basic torque command value can be regarded as zero, compared with the case where the absolute value of the basic torque command value cannot be regarded as zero, the change in the limit value according to the absolute value of the basic torque command value is made slower.

Advantages of the Invention

[0009] According to the present invention, it is possible to provide a control method and a control device for an electric vehicle that can suppress vibration of a torque transmission system even when a torque command value is extremely small.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Modes for Carrying Out the Invention

[0011] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0012] [First Embodiment] FIG. 1 is an explanatory diagram showing a schematic configuration of an electric vehicle 100. As shown in FIG. 1, the electric vehicle 100 is an electric vehicle, a hybrid vehicle, or the like including a rotating electric machine 10 that is an electric motor or a generator, and a controller 11.

[0013] In the present embodiment, the rotating electric machine 10 is an electric motor and functions as a drive source of the electric vehicle 100. That is, the output shaft of the rotating electric machine 10 is connected to the drive wheels 13 via a vehicle drive system (torque transmission system) constituted by a drive shaft DS, a gear 12, and the like.

[0014] The rotational state of the rotating electric machine 10 can be appropriately detected by a rotation detector 14. That is, parameters such as the position (electrical angle or mechanical angle) of the rotor included in the rotating electric machine 10, the angular velocity ω m [rad / s] (electrical angular velocity or mechanical angular velocity), and the rotational speed N m [rpm] and the like can be detected at substantially any timing. In the present embodiment, the rotational speed N m is assumed to be detected as the rotational state of the rotating electric machine 10.

[0015] The controller 11 is a control device of the electric vehicle 100 and is constituted by, for example, one or a plurality of computers or other arithmetic circuits. In the present embodiment, the controller 11 drives the electric vehicle 100 by controlling the rotating electric machine 10. For this purpose, the controller 11 includes, for example, a torque setting unit 15, a vibration suppression control unit 16, and a torque control unit 17.

[0016] The torque setting unit 15 calculates a basic torque command value T po based on the accelerator opening A m and the rotational speed N m1 * of the rotating electric machine 10. The accelerator opening A po is a parameter (detection value) representing the operation amount of the accelerator pedal and is appropriately acquired by a sensor (not shown). The basic torque command value T m1 * is the torque T mThat is, the torque T required by the operation of the accelerator pedal m is a command value representing it.

[0017] In this embodiment, the torque setting unit 15 has a torque map (not shown) that associates the accelerator opening A po and the rotational speed N m with the torque T m . This torque map is determined in advance by experiments or simulations. Therefore, the torque setting unit 15 refers to this torque map to determine the torque T po corresponding to the accelerator opening A m and the rotational speed N m . Then, the torque T po corresponding to the accelerator opening A m and the rotational speed N m is processed by a filter having a transfer characteristic represented by G m (s) / G p (s) to calculate the basic torque command value T m1 * . G m (s) is an ideal transfer characteristic model indicating the response target from the input of the torque T m to the output of the rotational speed N m . Also, G p (s) is a realistic transfer characteristic model representing the response from the input of the torque T m to the output of the rotational speed N m .

[0018] Note that instead of calculating the basic torque command value T m1 * itself as described above, the torque setting unit 15 may obtain the basic torque command value T m1 * from another controller (not shown) or the like.

[0019] The vibration damping control unit 16 corrects the basic torque command value T m1 * so that the vibration generated in the vehicle drive system is reduced, and the torque command value (hereinafter, the vibration damping torque command value T m2 *It calculates (such as). The configuration of the vibration suppression control unit 16 will be described in detail later.

[0020] The torque control unit 17 controls the rotating electrical machine 10 based on the vibration suppression torque command value T m2 * That is, the torque control unit 17 controls the rotation of the rotating electrical machine 10 so that the torque T m of the rotating electrical machine 10 coincides with (or follows) the vibration suppression torque command value Tm2*. The torque control unit 17 is composed of, for example, a PWM signal generation unit that generates a PWM (Pulse Width Modulation) signal, and an inverter that controls the voltage applied to the rotating electrical machine 10 based on the PWM signal.

[0021] FIG. 2 is a block diagram showing the configuration of the vibration suppression control unit 16. As shown in FIG. 2, the vibration suppression control unit 16 includes an addition unit 21, a rotation speed estimation unit 22, a subtraction unit 23, a feedback torque calculation unit 24, and a feedback torque limitation unit 25.

[0022] The addition unit 21 calculates the vibration suppression torque command value T m1 * by adding the limited feedback torque T FB-lmt to the basic torque command value T m2 * . That is, the vibration suppression control unit 16 corrects the basic torque command value T FB-lmt by adding the limited feedback torque T m1 * to calculate the vibration suppression torque command value T m2 * which is the final torque command value.

[0023] The rotation speed estimation unit 22 calculates an estimated value of the rotation speed N m2 * (hereinafter referred to as the rotation speed estimated value N m ^) based on the vibration suppression torque command value T m . The rotation speed estimated value N m ^ is the state where there is no influence of the disturbance torque T d and in an ideal state, the rotating electrical machine 10 has the vibration suppression torque command value Tm2 * Torque T corresponding thereto m The ideal rotational speed N in the case of outputting m is. The rotational speed estimation unit 22 is, for example, a transfer characteristic G p configured by a filter represented by (s). Note that the disturbance d is the rotational speed N m other than the input of the torque T m includes all factors that vary. In the present embodiment, the disturbance torque T d is the torque generated mainly by vibrations occurring in the vehicle drive system, more specifically, the torsional vibration of the drive shaft DS.

[0024] The subtraction unit 23 subtracts the detected rotational speed N m (hereinafter, when it is necessary to distinguish from the estimated value, the rotational speed detection value N m is referred to) and the rotational speed estimated value N m ^, and calculates the deviation (hereinafter, referred to as the rotational speed deviation ΔN m ). In the present embodiment, the subtraction unit 23 subtracts the rotational speed detection value N m from the rotational speed estimated value N m to calculate the rotational speed deviation ΔN m . The rotational speed detection value N m is the actual rotational speed N d affected by the disturbance torque T m .

[0025] The feedback torque calculation unit 24 calculates the feedback torque T m based on the rotational speed deviation ΔN FB . The feedback torque T FB is the torque to be fed back to the basic torque command value T d in order to suppress the variation of the rotational speed N m caused by the disturbance torque T m1 * . The feedback torque calculation unit 24 is configured by, for example, a filter having a transfer characteristic represented by H(s) / G p (s). H(s) is the transfer characteristic of a band-pass filter that passes components corresponding to the resonance frequency of torsional vibrations occurring in the vehicle drive system. Gp (s), as described above, is the torque T m from the input to the rotational speed N m is a realistic transfer characteristic model representing the response up to the output of

[0026] The feedback torque limiter 25 sets the limit value T FB for the absolute value |T FB | of the feedback torque T lmt . Then, the feedback torque limiter 25 restricts the feedback torque T FB so that the absolute value |T FB | of the feedback torque T lmt is less than or equal to the limit value T FB , and outputs the limited feedback torque T FB-lmt . In this embodiment, the limit value T lmt is a non - negative value (T lmt ≥ 0).

[0027] When the absolute value |T FB | of the feedback torque T FB is less than or equal to the limit value T lmt , the feedback torque limiter 25 outputs the input feedback torque T FB as it is as the limited feedback torque T FB-lmt . In this case, when the feedback torque T FB is a positive value, the limited feedback torque T FB-lmt is also a positive value, and when the feedback torque T FB is a negative value, the limited feedback torque T FB-lmt is also a negative value.

[0028] On the other hand, when the absolute value |T FB | of the feedback torque T FB exceeds the limit value T lmt , the feedback torque limiter 25 outputs the limit value T lmt as the limited feedback torque T FB-lmt . In this case, when the feedback torque T FB is a positive value, the limited feedback torque TFB-lmt is the limited value T with a positive sign lmt (i.e., +T lmt ). When the feedback torque T FB is a negative value, the limited feedback torque T FB-lmt is the limited value T with a negative sign lmt (i.e., -T lmt ).

[0029] Furthermore, the feedback torque limiter 25 changes the limited value T lmt in accordance with the absolute value |T m1 * | of the basic torque command value T m1 * .

[0030] Specifically, the feedback torque limiter 25 generally uses the absolute value |T m1 * | of the basic torque command value T m1 * as the limited value T lmt to change the limited value T lmt in accordance with the absolute value |T m1 * | of the basic torque command value T m1 * .

[0031] As a result, the limited feedback torque T FB-lmt will not exceed the basic torque command value T m1 * , so the basic torque command value T m1 * and the vibration damping torque command value T m2 * are maintained with the same sign. That is, when the basic torque command value T m1 * is a non - negative value, the vibration damping torque command value T m2 * is also maintained as a non - negative value (T m2 * ≥0), and when the basic torque command value T m1 * is a non - positive value (T m1 *≦ 0), the vibration damping torque command value T m2 * is maintained at a non-positive value (T m2 * ≦ 0). As a result, by executing vibration damping control to suppress (reduce) the torsional vibration of the vehicle drive system, it is possible to prevent noise caused by the backlash of the gear 12 from occurring.

[0032] However, when the absolute value |T m1 * | of the basic torque command value T m1 * is a very small value that can be regarded as substantially zero, the feedback torque T FB is also limited to a very small value that can be regarded as substantially zero. For this reason, in a scene where the absolute value |T m1 * | of the basic torque command value T m1 * can be regarded as substantially zero, the vibration damping control is substantially ineffective. Therefore, in a scene where the absolute value |T m1 * | of the basic torque command value T m1 * can be regarded as substantially zero, when torsional vibration of the vehicle drive system occurs or remains, that torsional vibration is not suppressed.

[0033] For example, when the driver releases the accelerator or when the shift position is switched from the D range to the N range, the basic torque command value T m1 * becomes almost instantaneously zero. On the other hand, since the rotation of the rotating electrical machine 10 remains, torsional vibration occurs in the vehicle drive system. However, since the feedback torque T m1 * is also limited to zero due to the basic torque command value T FB becoming zero, the vibration damping control does not function substantially, so the torsional vibration generated in these scenes is not suppressed.

[0034] Therefore, in the present embodiment, the absolute value |T m1 * | of the basic torque command value Tm1 * In a scene where | can be regarded as zero, the feedback torque limiting unit 25 makes the change in the limit value T m1 * corresponding to T lmt less sharp. More precisely, at least when the absolute value |T m1 * | of the basic torque command value T m1 * can be regarded as zero, the feedback torque limiting unit 25 makes the change in the limit value T m1 * corresponding to the absolute value |T m1 * of the basic torque command value T m1 * less sharp compared to the case where the absolute value |T m1 * of the basic torque command value T lmt cannot be regarded as zero. As a result, even after the basic torque command value T m1 * substantially becomes zero, the restricted feedback torque T FB-lmt can have a significant value (non-zero value) for a while. As a result, the torsional vibration of the vehicle drive system that occurred when the basic torque command value T m1 * is extremely small and can be regarded as zero is also suppressed by the above vibration damping control.

[0035] FIG. 3 is an explanatory diagram showing a dynamic model of the electric vehicle 100. Each parameter shown in FIG. 4 is as follows.

[0036] J m : Inertia of the rotating electrical machine J w : Inertia of the drive wheels M: Mass of the vehicle K D : Torsional stiffness of the wheel drive system K T : Coefficient related to the friction between the drive wheels and the road surface N: Overall gear ratio r: Load radius of the drive wheels ω m : Angular velocity of the rotating electrical machine T m : Torque of the rotating electrical machine T D : Torque of the drive wheel F: Force applied to the electric vehicle V: Speed of the electric vehicle (vehicle speed) ω w : Angular velocity of the drive wheel

[0037] From the dynamic model of the electric vehicle 100 shown in FIG. 3, the following equations of motion (1) to (5) can be derived.

[0038]

Equation

[0039] The transmission characteristic G m from the input of the torque T m to the output of the rotational speed N p (s) can be obtained from the above equations of motion (1) to (5) and is represented by the following equation (6). Also, the coefficients a1 to a4 and the coefficients b0 to b3 in equation (6) are represented by equations (7) to (14). Note that "s" is the Laplace operator.

[0040]

Equation

[0041] When examining the poles and zeros of the transmission characteristic G p (s), one pole and one zero show extremely close values. This means that the transmission characteristic G p (s) can be represented in the form of the following equation (15), and α and β in the following equation (15) show extremely close values.

[0042]

Equation

[0043] Therefore, by performing pole-zero cancellation that approximates α = β in Equation (15), the transfer characteristic G of the (second order) / (third order) form can be obtained as shown in the following Equation (16). p (s). Further, using the resonance angular frequency ω p (resonance frequency f p = ω p / 2π) and the damping coefficient ξ p , the transfer characteristic G p (s) is expressed in the form of the following Equation (17). The transfer characteristic B p (s) in Equation (17) is a transfer characteristic that functions as a band-pass filter for the input. Therefore, the substantial responsiveness of the transfer characteristic G p (s) is determined by the denominator part of Equation (17), particularly the part of (s 2 +2ξ p ω p s + ω p 2 ).

[0044]

Number

[0045] In the controller 11, the above transfer characteristic G p (s) is discretized and used by performing z-transform according to the following Equation (18). The same applies to other transfer characteristics described later. In Equation (18), "T" is the sampling time.

[0046]

Number

[0047] Figure 4 is a graph showing the characteristics of the band-pass filter H(s). The feedback torque calculation unit 24 is an element that selectively extracts the torsional vibration components generated in the vehicle drive system. Therefore, as shown in Figure 4, the band-pass filter H(s) used in the feedback torque calculation unit 24 (H(s) / G p (s)) has the resonance frequency f of torsional vibrationp It is preferable to have the characteristic of selectively passing the components of p . In particular, the attenuation characteristics on the high-frequency side and the low-frequency side are substantially the same, and the resonance frequency f p is preferably the frequency approximately at the center of the passband. In FIG. 4, the cut-off frequency on the high-frequency side is represented by f cH and the cut-off frequency on the low-frequency side is represented by f cL as shown.

[0048] The band-pass filter H(s) as described above can be constituted by, for example, a first-order low-pass filter and a high-pass filter. In this case, the band-pass filter H(s) can be represented by the following formula (19). That is, the band-pass filter H(s) is expressed by the product of the gain k, the low-pass filter (ω p / (s + ω p )) and the high-pass filter (s / (s + ω p )) using the resonance angular frequency ω p ).

[0049]

Equation

[0050] The gain k of the band-pass filter H(s) can be determined as follows.

[0051] First, as can be seen from FIG. 2, assuming that the disturbance torque T d due to the torsional vibration of the vehicle drive system occurs, the rotational speed N m is expressed by the following formula (20), and the estimated rotational speed N m ^ is expressed by the following formula (21). Then, the rotational speed deviation ΔN m which is the deviation between these can be expressed as shown in the following formula (22). Further, the feedback torque T FB can be expressed by the following formula (23).

[0052]

Equation

[0053] Here, the basic torque command value T m1 * is set to zero (T m1 * = 0), and considering the case where the vibration damping torque command value T m2 * is represented by the feedback torque T FB (T m2 * = T FB ), based on equations (20) and (23), the rotational speed N m can be expressed by the following equation (24).

[0054]

Equation

[0055] Therefore, according to equations (17) and (19), the transfer characteristics (G d from the disturbance torque T m to the rotational speed N p (s)(1 - H(s))) are represented by the following equation (25).

[0056]

Equation

[0057] Therefore, in order to most efficiently obtain the vibration damping effect on the disturbance torque T d , the gain k may be determined so as to satisfy the following equation (26). Therefore, the gain k is represented by the following equation (27). At this time, the band - pass filter H(s) is represented by the following equation (28). Also, the transfer characteristics (G d from the disturbance torque T m to the rotational speed N p (s)(1 - H(s))) are pole - zero canceled and represented by the following equation (29).

[0058]

Equation

[0059] FIG. 5 is a block diagram showing the configuration of the feedback torque limiting unit 25. As shown in FIG. 5, the feedback torque limiting unit 25 includes an absolute value calculation unit 31, a limit value setting unit 32, and a limiting unit 33.

[0060] The absolute value calculation unit 31 calculates the absolute value |T| of the basic torque command value T. m1 * The absolute value |T| of the basic torque command value T is input to the limit value setting unit 32. m1 * The absolute value |T| of the basic torque command value T is input to the limit value setting unit 32. m1 * The absolute value |T| of the basic torque command value T is input to the limit value setting unit 32. m1 * The absolute value |T| of the basic torque command value T is input to the limit value setting unit 32.

[0061] The limit value setting unit 32 sets a limit value T for the feedback torque T based on the absolute value |T| of the basic torque command value T. The limit value setting unit 32 is composed of a reference torque calculation unit 41 and a limit value selection unit 42. m1 * The limit value setting unit 32 sets a limit value T for the feedback torque T based on the absolute value |T| of the basic torque command value T. The limit value setting unit 32 is composed of a reference torque calculation unit 41 and a limit value selection unit 42. m1 * The limit value setting unit 32 sets a limit value T for the feedback torque T based on the absolute value |T| of the basic torque command value T. The limit value setting unit 32 is composed of a reference torque calculation unit 41 and a limit value selection unit 42. FB The limit value setting unit 32 sets a limit value T for the feedback torque T based on the absolute value |T| of the basic torque command value T. The limit value setting unit 32 is composed of a reference torque calculation unit 41 and a limit value selection unit 42. lmt The limit value setting unit 32 sets a limit value T for the feedback torque T based on the absolute value |T| of the basic torque command value T. The limit value setting unit 32 is composed of a reference torque calculation unit 41 and a limit value selection unit 42.

[0062] The reference torque calculation unit 41 calculates a reference torque T based on the absolute value |T| of the basic torque command value T. m1 * The reference torque calculation unit 41 calculates a reference torque T based on the absolute value |T| of the basic torque command value T. m1 * The reference torque T is a torque that changes according to the absolute value |T| of the basic torque command value T and is adjusted so that the change is slower than the change in the basic torque command value T itself. That is, the reference torque T is obtained by dulling the change (temporal change) of the basic torque command value T. ref The reference torque T is a torque that changes according to the absolute value |T| of the basic torque command value T and is adjusted so that the change is slower than the change in the basic torque command value T itself. That is, the reference torque T is obtained by dulling the change (temporal change) of the basic torque command value T. ref The reference torque T is a torque that changes according to the absolute value |T| of the basic torque command value T and is adjusted so that the change is slower than the change in the basic torque command value T itself. That is, the reference torque T is obtained by dulling the change (temporal change) of the basic torque command value T. m1 * The reference torque T is a torque that changes according to the absolute value |T| of the basic torque command value T and is adjusted so that the change is slower than the change in the basic torque command value T itself. That is, the reference torque T is obtained by dulling the change (temporal change) of the basic torque command value T. m1 * The reference torque T is a torque that changes according to the absolute value |T| of the basic torque command value T and is adjusted so that the change is slower than the change in the basic torque command value T itself. That is, the reference torque T is obtained by dulling the change (temporal change) of the basic torque command value T. ref The reference torque T is a torque that changes according to the absolute value |T| of the basic torque command value T and is adjusted so that the change is slower than the change in the basic torque command value T itself. That is, the reference torque T is obtained by dulling the change (temporal change) of the basic torque command value T. m1 * The reference torque T is a torque that changes according to the absolute value |T| of the basic torque command value T and is adjusted so that the change is slower than the change in the basic torque command value T itself. That is, the reference torque T is obtained by dulling the change (temporal change) of the basic torque command value T.

[0063] Specifically, the reference torque calculation unit 41 is constituted by a filter having a transfer characteristic H ref (s) shown in the following equation (30). The transfer characteristic H ref (s) is from the disturbance torque T d to the rotational speed N m up to the transfer characteristic (G p (s)(1 - H(s))) can be expressed by equation (29), based on which the feedback torque T d with respect to the disturbance torque T FB is a transfer characteristic that simulates the responsiveness. Therefore, the reference torque T ref is T ref = H ref (s)|T m1 * | obtained thereby. Note that the transfer characteristic H ref (s) is set such that the gain at steady state is 1.

[0064]

Equation

[0065] The reference torque T ref is obtained, as described above, by slowing down the change in the basic torque command value T ref (s). Therefore, even when the basic torque command value T m1 * suddenly becomes zero and torsional vibration of the vehicle drive system occurs due to its influence (such as backlash), the reference torque T m1 * does not immediately become zero. That is, the reference torque T ref transiently holds a significant value for at least the response time of the feedback torque T ref necessary for suppressing the torsional vibration. FB

[0066] The limit value selection unit 42 is the absolute value |T m1 * | of the basic torque command value T m1 * ​or the reference torque T ref Select any one of them and set it as the limit value T lmt to set.

[0067] In this embodiment, the limit value selection unit 42 compares the absolute value |T m1 * | of the basic torque command value T m1 * with the threshold value ε. The threshold value ε is a threshold value that defines a range in which the basic torque command value T m1 * can be regarded as substantially zero, and is determined in advance by experiments or simulations, etc., by adaptation. And when the absolute value |T m1 * | of the basic torque command value T m1 * | is greater than the threshold value ε and the basic torque command value T m1 * cannot be regarded as substantially zero, the limit value selection unit 42 sets the absolute value |T m1 * | of the basic torque command value T m1 * as the limit value T lmt to set. On the other hand, when the absolute value |T m1 * | of the basic torque command value T m1 * | is less than or equal to the threshold value ε and the basic torque command value T m1 * can be regarded as substantially zero, the limit value selection unit 42 sets the reference torque T ref as the limit value T lmt to set.

[0068] The limiting unit 33 outputs a limited feedback torque T lmt by limiting the feedback torque T FB according to the limit value T FB-lmt . Specifically, the limiting unit 33 limits the feedback torque T FB so that the absolute value |T FB | of the feedback torque T lmt is less than or equal to the limit value T FB . That is, the feedback torque T FBThe absolute value of |T FB | is the limit value T lmt When it is below, the limiting unit 33 uses the feedback torque T FB as it is as the limited feedback torque T FB-lmt and outputs it. On the other hand, when the absolute value of the feedback torque T FB |T FB | exceeds the limit value T lmt the limiting unit 33 outputs the limit value T FB with the same sign as the input feedback torque T lmt .

[0069] The operation of the vibration control in the electric vehicle 100 configured as described above will be described below.

[0070] FIG. 6 is a flowchart related to the switching of the limit value T FB for the feedback torque T lmt . As shown in FIG. 6, in step S10, the accelerator opening A po and the rotational speed N m are detected, and the controller 11 acquires them. In step S11, the torque setting unit 15 calculates the basic torque command value T po based on the accelerator opening A m and the rotational speed N m1 * . In step S12, the feedback torque calculation unit 24 calculates the feedback torque T m based on the rotational speed N FB (rotational speed detection value), etc.

[0071] In step S13, the limit value setting unit 32 determines whether the absolute value of the basic torque command value T m1 * |T m1 * | is small enough to be regarded as substantially zero by comparing it with the threshold value ε. And whether the absolute value of the basic torque command value T m1 * |T m1 * | is small enough to be regarded as substantially zero. m1 *|is equal to or less than the threshold ε, and the basic torque command value T m1 * can be regarded as zero, the process proceeds to step S14, and the transfer characteristic H ref (s) is used to dull the basic torque command value T m1 * to obtain the reference torque T ref which is set to the limit value T lmt On the other hand, when the absolute value |T m1 * | of the basic torque command value T m1 * is greater than the threshold ε and the basic torque command value T m1 * cannot be regarded as zero, the process proceeds to step S15, and the absolute value |T m1 * | of the basic torque command value T m1 * | is set to the limit value T lmt .

[0072] In step S16, the limiting unit 33 calculates the limited feedback torque T lmt by limiting the absolute value |T FB | of the feedback torque T FB based on the limit value T FB-lmt . Then, in step S17, the addition unit 21 adds the limited feedback torque T m1 * to the basic torque command value T FB-lmt to calculate the vibration suppression torque command value T m2 * . After that, in step S17, the torque control unit 17 executes torque control so that the torque T m of the rotating electrical machine 10 coincides (follows) with the vibration suppression torque command value T m2 * .

[0073] FIG. 7 shows the basic torque command value T m1 * , the feedback torque T FB , and the limited feedback torque T FB-lmtIt is a graph showing transitions such as this. In FIG. 7, from the state where the accelerator pedal is being operated, at time t0, the accelerator pedal is released, and the accelerator opening A po shows a scene where it almost instantaneously becomes zero. Also, FIGS. 7(A) to (D) are graphs related to the comparative example, and FIGS. 7(E) to (H) are graphs related to the present embodiment. In the comparative example, regardless of whether the basic torque command value T m1 * is a value small enough to be regarded as substantially zero, the absolute value |T m1 * of the basic torque command value T m1 * is set to the limit value T lmt . That is, in the present embodiment, depending on whether the basic torque command value T m1 * is a value small enough to be regarded as substantially zero, the limit value T lmt is switched between the absolute value |T m1 * | of the basic torque command value T m1 * and the reference torque T ref , whereas in the comparative example, such switching of the limit value T lmt is not performed.

[0074] Specifically, FIG. 7(A) shows the basic torque command value T m1 * and the vibration damping torque command value T m2 * in the comparative example. In FIG. 7(A), the basic torque command value T m1 * is shown by a broken line, and the vibration damping torque command value T m2 * is shown by a solid line. FIG. 7(B) shows the feedback torque T FB , the limited feedback torque T FB-lmt , and the limit value T lmt in the comparative example. In FIG. 7(B), the feedback torque T FB is shown by a broken line, the limited feedback torque T FB-lmt is shown by a solid line, and the limit value T lmt is shown by a one-dot chain line. FIG. 7(C) shows the rotational speed N in the comparative examplem is shown. FIG. 7(D) shows the torque of the drive shaft DS in the comparative example (hereinafter referred to as the drive shaft torque T DS ).

[0075] Similarly, FIG. 7(E) shows the basic torque command value T m1 * and the vibration damping torque command value T m2 * in the present embodiment. In FIG. 7(E), the basic torque command value T m1 * is indicated by a broken line, and the vibration damping torque command value T m2 * is indicated by a solid line. FIG. 7(F) shows the feedback torque T FB , the restricted feedback torque T FB-lmt , and the limit value T lmt in the present embodiment. In FIG. 7(F), the feedback torque T FB is indicated by a broken line, the restricted feedback torque T FB-lmt is indicated by a solid line, and the limit value T lmt is indicated by a dashed-dotted line. FIG. 7(G) shows the rotational speed N m in the present embodiment. FIG. 7(H) shows the drive shaft torque T DS in the present embodiment.

[0076] As shown in FIG. 7(A), when the accelerator opening A po becomes zero at time t0, the basic torque command value T m1 * converges toward zero accordingly. At this time, since the rotation of the rotary electric machine 10 remains, as shown in FIG. 7(B), after time t0, a feedback torque T m occurs according to the fluctuation of the rotational speed N FB .

[0077] However, in the comparative example, regardless of the magnitude of the basic torque command value T m1 * , the absolute value |T m1 * | of the basic torque command value T m1 * is directly the limit value Tlmt continues to be used. For this reason, as shown in FIG. 7(B), the limit value T lmt converges steeply to zero in accordance with the convergence of the basic torque command value T m1 * . Then, as indicated by the arrow in FIG. 7(B), before the feedback torque T FB fully converges, it is restricted by the limit value T lmt . Also, when the limit value T lmt becomes zero at time t1, vibration control is no longer substantially effective thereafter. Therefore, as shown in FIG. 7(C), even after time t1, an oscillatory component remains in the rotational speed N m . As a result, as shown in FIG. 7(D), the torsional vibration of the vehicle drive system is not sufficiently suppressed, and vibration control becomes ineffective, leaving torsional vibration remaining for a long time.

[0078] Also, as shown in FIG. 7(D), the vibration of this drive shaft torque T DS (torsional vibration of the drive shaft DS) crosses zero, which may cause noise due to the backlash of gear 12. The purpose of restricting the feedback torque T FB is, in principle, to prevent noise due to the backlash of gear 12. Therefore, as in the comparative example, until the basic torque command value T m1 * is small enough to be regarded as almost zero, if the absolute value |T m1 * | of the basic torque command value T m1 * is continuously used as the limit value T lmt , the significance of restricting the feedback torque T FB may be lost.

[0079] As shown in FIG. 7(E), also in this embodiment, as in the comparative example, when the accelerator opening A po becomes zero at time t0, the basic torque command value T m1 * also converges toward zero accordingly. At this time, as shown in FIG. 7(F), the rotational speed N mFeedback torque T corresponding to the variation FB occurs. This is the same as in the comparative example.

[0080] However, in the present embodiment, when the basic torque command value T m1 * is a value small enough to be regarded as almost zero, instead of continuously using the absolute value |T m1 * | of the basic torque command value T m1 * as the limit value T lmt , the reference torque T ref is set as the limit value T lmt . The reference torque T ref is obtained by slowing down the change of the basic torque command value T FB in consideration of the response time of the feedback torque T m1 * . Therefore, as shown in FIG. 7(F), in the present embodiment, by using the reference torque T ref , the change of the limit value T lmt becomes slower than in the comparative example.

[0081] As a result, in the present embodiment, in a scene where the basic torque command value T m1 * becomes a small value that can be regarded as almost zero, it becomes difficult for the feedback torque T FB to be restricted by the limit value T lmt . Also, as indicated by the arrow in FIG. 7(F), in the present embodiment as well, although the feedback torque T FB may be restricted by the limit value T lmt , the timing is likely to be after the feedback torque T FB has sufficiently converged.

[0082] Therefore, as shown in FIG. 7(G), when the limit value T lmt becomes zero at time t1' and the vibration control substantially becomes ineffective, the oscillatory component of the rotational speed N m is suppressed. As a result, as shown in FIG. 7(H), the basic torque command value Tm1 * Even in a scene where it can be regarded as almost zero, in the present embodiment, the torsional vibration of the vehicle drive system is suppressed.

[0083] [Second Embodiment] In the above first embodiment, when the basic torque command value T m1 * is a value small enough to be substantially regarded as zero, regardless of the increase or decrease in the absolute value |T m1 * | of the basic torque command value T m1 * |, the change in the limit value T lmt is made slow, but it is not limited to this. In the present second embodiment, when the basic torque command value T m1 * is a value small enough to be substantially regarded as zero, further, depending on the increase or decrease in the absolute value |T m1 * | of the basic torque command value T m1 * |, an example of determining whether to slow down the change in the limit value T lmt will be described.

[0084] FIG. 8 is a block diagram showing the configuration of the feedback torque limiting unit 25 according to the second embodiment. As shown in FIG. 8, the feedback torque limiting unit 25 of the second embodiment includes an absolute value calculation unit 31, a limit value setting unit 32, and a limiting unit 33. These functions are the same as those of the first embodiment. However, in the second embodiment, the limit value setting unit 32 is composed of a reference torque calculation unit 41, a comparison unit 50, and a limit value selection unit 42.

[0085] The reference torque calculation unit 41, in the same manner as in the first embodiment, processes the absolute value |T m1 * | of the basic torque command value T by a filter represented by the transfer characteristic H m1 * (s) to calculate the reference torque T ref . ref

[0086] The comparison unit 50 compares the absolute value |T m1 * of the basic torque command value T m1 * | with the reference torque T ref and outputs either the absolute value |T m1 * of the basic torque command value T m1 * | or the reference torque T ref as the limit value T lmt according to the determination result. In this embodiment, the comparison unit 50 is a maximum value calculator (MAX), and outputs the larger value of the absolute value |T m1 * | of the basic torque command value T m1 * and the reference torque T ref .

[0087] As described above, since the reference torque T ref is a value that dulls the change of the basic torque command value T m1 * , when the absolute value |T m1 * | of the basic torque command value T m1 * decreases, the reference torque T ref is larger than the absolute value |T m1 * | of the basic torque command value T m1 * . On the other hand, when the basic torque command value T m1 * increases, the reference torque T ref is smaller than the absolute value |T m1 * | of the basic torque command value T m1 * . Therefore, when the absolute value |T m1 * | of the basic torque command value T m1 * decreases, the comparison unit 50 outputs the reference torque T ref . On the other hand, when the basic torque command value Tm1 * When the absolute value |T m1 * | increases, the basic torque command value T m1 * of the absolute value |T m1 * | is output.

[0088] The limit value selection unit 42 determines whether the absolute value |T m1 * of the basic torque command value T m1 * | can be regarded as substantially zero by comparing it with the threshold value ε. Specifically, when the absolute value |T m1 * of the basic torque command value T m1 * is greater than the threshold value ε and the basic torque command value T m1 * cannot be regarded as substantially zero, the limit value selection unit 42 sets the absolute value |T m1 * of the basic torque command value T m1 * to the limit value T m1 * |. On the other hand, when the absolute value |T lmt of the basic torque command value T m1 * is less than or equal to the threshold value ε and the basic torque command value T m1 * can be regarded as substantially zero, the limit value selection unit 42 sets the output of the comparison unit 50 to the limit value T m1 * |. lmt to the limit value T

[0089] That is, when the absolute value |T m1 * of the basic torque command value T m1 * is less than or equal to the threshold value ε and the reference torque T ref is greater than the absolute value |T m1 * of the basic torque command value T m1 * |, the limit value Tlmt is the reference torque T refis set. And the reference torque T ref is the basic torque command value T m1 * is less than or equal to the absolute value of |T m1 * |, when the absolute value of the basic torque command value T m1 * is less than or equal to the threshold value ε, even if the absolute value of |T m1 * |, the limit value T lmt is set to the absolute value of the basic torque command value T m1 * |T m1 * |.

[0090] As described above, in a scene where the absolute value of the basic torque command value T m1 * |T m1 * | can be regarded as substantially zero, the feedback torque limiting unit 25 of the second embodiment, as in the first embodiment, in principle, sets the reference torque T ref to the limit value T lmt to slow down the change of the limit value T lmt . However, even in a scene where the absolute value of the basic torque command value T m1 * |T m1 * | can be regarded as substantially zero, when the absolute value of the basic torque command value T m1 * |T m1 * | increases, that is, when the basic torque command value T m1 * moves away from zero, the feedback torque limiting unit 25 of the second embodiment, exceptionally, changes the limit value T lmt in accordance with the absolute value of the basic torque command value T m1 * |T m1 * |.

[0091] That is, the feedback torque limiting unit 25 of the second embodiment is the absolute value of the basic torque command value T m1 * |Tm1 * In a scene where it can be regarded as substantially zero, the basic torque command value T m1 * The absolute value of |T m1 * When the limit value T lmt When the change of the basic torque command value T m1 * The absolute value of |T m1 * When the limit value T lmt The change of the limit value T is made larger than the change when the absolute value |T lmt is set.

[0092] Figure 9 is a flowchart related to the switching of the limit value T lmt in the second embodiment. As shown in Figure 9, the switching of the limit value T lmt in the second embodiment is provided with step S20 between step S13 and step S14 in the switching of the limit value T lmt according to the first embodiment (see Figure 6).

[0093] That is, in the second embodiment, in step S13, when the absolute value |T m1 * of the basic torque command value T m1 * | is less than or equal to the threshold value ε and the basic torque command value T m1 * can be regarded as zero, proceed to step S20. Then, in step S20, the limit value setting unit 32 further compares the absolute value |T m1 * of the basic torque command value T m1 * | with the reference torque T ref to determine whether the absolute value |T m1 * of the basic torque command value T m1 * | is in a scene of increasing.

[0094] In step S20, when the reference torque T ref is the basic torque command value Tm1 * The absolute value of |T m1 * is greater than the absolute value of the basic torque command value T m1 * The absolute value of |T m1 * | is decreasing, that is, when it is determined that the scene is such that the basic torque command value T m1 * is approaching zero, proceed to step S14. Then, in step S14, the limit value setting unit 32 sets the reference torque T ref to the limit value T lmt .

[0095] On the other hand, in step S20, when it is determined that the reference torque T ref is smaller than the absolute value of the basic torque command value T m1 * The absolute value of |T m1 * | and the absolute value of the basic torque command value T m1 * The absolute value of |T m1 * | is increasing, proceed to step S15. Then, in step S15, the limit value setting unit 32 sets the absolute value of the basic torque command value T m1 * The absolute value of |T m1 * | to the limit value T lmt .

[0096] As described above, in a scene where the basic torque command value T m1 * can be regarded as substantially zero, as in the first embodiment, in principle, the change in the limit value T lmt should be slow. However, even when the basic torque command value T m1 * can be regarded as substantially zero, in a scene where the absolute value of the basic torque command value T m1 * The absolute value of |T m1 * | is increasing, if the change in the limit value T lmt is made slow, the feedback torque T FBwill be subject to stricter restrictions for a longer period of time.

[0097] For example, when the electric vehicle 100 is suddenly started from a stopped state, the basic torque command value T m1 * On the other hand, the reference torque T ref is the basic torque command value T m1 * Absolute value of |T m1 * In this case, the limit value T lmt Reference torque T ref When set to , the feedback torque T FB is the limit value T lmt The basic torque command value T m1 * Absolute value of |T m1 * As a result, it may become difficult to suppress torsional vibration of the drive shaft DS that occurs when the electric vehicle 100 is suddenly accelerated from a stopped state.

[0098] Therefore, the basic torque command value T m1 * Even if the basic torque command value T m1 * Absolute value of |T m1 * In the scene where | increases, as shown above, the limit value T lmt The basic torque command value T m1 * Absolute value of |T m1 * In this way, when the accelerator pedal is released, the basic torque command value T m1 * When approaches zero, the feedback torque T FB is the limit value T lmt Since the torque command value T m1 * In the scene where increases, the basic torque command value T m1* While the feedback torque T is a small value that can be regarded as substantially zero, FB the torsional vibration of the vehicle drive system is easily suppressed early without being overly severely restricted.

[0099] In the second embodiment, while the absolute value |T of the basic torque command value T m1 * can be regarded as substantially zero, and in a scene where the basic torque command value T m1 * increases, the limit value T m1 * is set to the absolute value |T of the basic torque command value T lmt but is not limited to this. The limit value T in this scene m1 * can be set to any value within a range where the followability with respect to the basic torque command value T m1 * is higher than that with respect to the reference torque T lmt That is, the limit value T in this scene ref is sufficient if it is larger than the change in the limit value T when the absolute value |T of the basic torque command value T m1 * decreases. However, the maximum value within the range where the limit value T ref can be set is the absolute value |T of the basic torque command value T lmt That is, the limit value T in this scene m1 * is sufficient if it is larger than the change in the limit value T when the absolute value |T of the basic torque command value T m1 * decreases. However, the maximum value within the range where the limit value T lmt can be set is the absolute value |T of the basic torque command value T lmt m1 * m1 * m * |.

[0100] As described above, the control method for an electric vehicle according to the above embodiment and the like calculates the feedback torque T based on the rotational state (N m ) of the rotating electric machine 10, corrects the torque command value (T FB ) based on the feedback torque T, and the corrected torque command value (T FB ) based on the feedback torque T, corrects the torque command value (T m1 * ) and the corrected torque command value (Tm2 * ) in accordance with which the rotating electrical machine 10 is controlled, a control method for the electric vehicle 100. In this control method for the electric vehicle 100, the feedback torque T FB of the absolute value |T FB | a limit value T lmt is set, and the limit value T lmt is changed according to the absolute value |T m1 * of the basic torque command value T m1 * which is the torque command value before correction. And when at least the absolute value |T m1 * of the basic torque command value T m1 * can be regarded as zero, compared with the case where the absolute value |T m1 * of the basic torque command value T m1 * cannot be regarded as zero, the change of the limit value T m1 * corresponding to the absolute value |T m1 * of the basic torque command value T lmt is made slower.

[0101] In order to reduce the noise caused by the backlash of the gear 12, when the limit value T lmt is changed by the absolute value |T m1 * of the basic torque command value T m1 * and the basic torque command value T m1 * approaches zero rapidly, accordingly, the vibration control by the feedback torque T FB also becomes ineffective. For this reason, the vibration of the torque transmission system that occurs (or remains) when the basic torque command value T m1 * approaches zero rapidly may not be sufficiently suppressed. On the contrary, as described above, when the basic torque command value T m1 * is a small value that can be regarded as substantially zero, the limit value T FB for the feedback torque T lmtSlowing down the change of m1 * when the basic torque command value T rapidly approaches zero, the feedback torque T FB is less likely to be restricted by the limit value T lmt . Therefore, when the basic torque command value T m1 * rapidly approaches zero, the vibration suppression control by the feedback torque T FB does not immediately become invalid, but for a while, the vibration suppression control by the feedback torque T FB is effective. Therefore, according to the control method of the electric vehicle described above, the vibration of the torque transmission system that occurs (or remains) when the basic torque command value T m1 * rapidly approaches zero is suppressed. For example, when the accelerator pedal is released or the shift position is changed from the D range to the N range, the torsional vibration of the vehicle drive system is suppressed. Note that in the steady state (scenes where the basic torque command value T m1 * cannot be regarded as substantially zero), while suppressing the vibration of the torque transmission system, the generation of noise due to the backlash of the gear 12 is suppressed.

[0102] In the control method of the electric vehicle according to the above embodiment, etc., the absolute value |T m1 * | of the basic torque command value T and the transfer characteristic H m1 * simulating the response from the disturbance torque T d to the feedback torque T FB are used to calculate the reference torque T ref . And when the absolute value |T ref | of the basic torque command value T m1 * cannot be regarded as zero, the limit value T m1 * is set to the absolute value |T lmt | of the basic torque command value T m1 * , and the absolute value |T m1 * | of the basic torque command value T m1 * ​m1 * When | can be regarded as zero, the limit value T lmt is set to the reference torque T ref .

[0103] In this way, the reference torque T ref calculated using the transfer characteristic H ref (s) is set to the limit value T lmt , and the absolute value |T m1 * of the basic torque command value T m1 * becomes just slow enough to suppress the vibration that occurs (remains) when the limit value T lmt changes according to the absolute value |T m1 * of the basic torque command value T m1 * rapidly approaches zero. That is, the transient feedback torque T FB can be generated by the necessary amount to suppress the vibration that occurs (remains) when the basic torque command value T m1 * rapidly approaches zero. Therefore, the vibration of the torque transmission system that occurs (or remains) when the basic torque command value T

[0104] rapidly approaches zero is particularly easily suppressed. m1 * In the control method of the electric vehicle according to the above embodiment etc. (especially the second embodiment), when the absolute value |T m1 * of the basic torque command value T m1 * can be regarded as zero, the change in the limit value T m1 * when the absolute value |T lmt of the basic torque command value T m1 * increases is larger than the change in the limit value T m1 * when the absolute value |T lmt of the basic torque command value T

[0105] decreases. In this way, the basic torque command value Tm1 * The absolute value of |T m1 * In a scene where | increases, the basic torque command value T m1 * The absolute value of |T m1 * Compared with a scene where | decreases, when the change in the limit value T lmt is increased, at the time of starting or the like, the feedback torque T FB is not overly strictly restricted, and the vibration of the torque transmission system is easily suppressed at an early stage. That is, the basic torque command value T m1 * The absolute value of |T m1 * | is decreased, by making the change in the limit value T lmt slower, the vibration of the torque transmission system occurring in this scene is preferably suppressed, and the basic torque command value T m1 * The absolute value of |T m1 * | is increased, by weakening the way of making it slower for the limit value T lmt the vibration of the torque transmission system occurring in this scene is preferably suppressed.

[0106] In the control method of the electric vehicle according to the above embodiment etc. (especially the second embodiment), the basic torque command value T m1 * The absolute value of |T m1 * | and the disturbance torque T d to the feedback torque T FB The transfer characteristic H ref (s) that simulates the response up to, are used to calculate the reference torque T ref and the basic torque command value T m1 * The absolute value of |T m1 * | and the reference torque T ref are compared, and by this, it is determined whether or not the absolute value of the basic torque command value T m1 * The absolute value of |T m1 * | increases. And the basic torque command value T m1* The absolute value |T m1 * | can be regarded as zero, and when the absolute value of the basic torque command value T m1 * |T m1 * | decreases, the limit value T lmt is set to the reference torque T ref On the other hand, even when the absolute value of the basic torque command value T m1 * |T m1 * | can be regarded as zero, when the absolute value of the basic torque command value T m1 * |T m1 * | increases, the limit value T lmt is set to the absolute value of the basic torque command value T m1 * |T m1 * |.

[0107] In this way, by comparing the absolute value |T m1 * | of the basic torque command value T m1 * | with the reference torque T ref , it is possible to easily and accurately determine whether the absolute value |T m1 * | of the basic torque command value T m1 * | increases. Then, in the scene where the absolute value |T m1 * | of the basic torque command value T m1 * | increases, by setting the limit value T m1 * | to the absolute value |T m1 * | of the basic torque command value T lmt , the vibration of the torque transmission system can be particularly preferably suppressed. m1 * |T m1 * |.

[0108] In the electric vehicle control method according to the above embodiment, etc., the basic torque command value T m1 * 's absolute value |T m1 * | is compared with a preset threshold value ε, and when the absolute value |T m1 * | of the basic torque command value T m1 * is less than or equal to the threshold value ε, it is determined that the absolute value |T m1 * | of the basic torque command value T m1 * can be regarded as zero, and when the absolute value |T m1 * | of the basic torque command value T m1 * is greater than the threshold value ε, it is determined that the absolute value |T m1 * | of the basic torque command value T m1 * cannot be regarded as zero.

[0109] Thus, by using the threshold value ε determined by adaptation through experiments or simulations, etc., whether the absolute value |T m1 * | of the basic torque command value T m1 * can be regarded as zero is determined, and the scene where the change of the limit value T lmt should be dulled can be discriminated particularly easily and accurately. Therefore, particularly accurately, the vibration of the torque transmission system that occurs (or remains) when the basic torque command value T m1 * rapidly approaches zero is suppressed.

[0110] The control device for an electric vehicle according to the above embodiment, etc. calculates a feedback torque T m based on the rotational state (N FB ) of the rotating electrical machine 10, corrects the torque command value (T FB ) based on the feedback torque T m1 * , and the corrected torque command value (T m2 *It is a control device (controller 11) of the electric vehicle 100 that controls the rotating electrical machine 10 in accordance with FB the absolute value |T FB | of the feedback torque T lmt to set a limit value T lmt and change the limit value T FB according to the absolute value |T m1 * | of the basic torque command value T m1 * which is the torque command value before correction by the feedback torque T m1 * and when the absolute value |T m1 * | of the basic torque command value T m1 * can be regarded as zero, compared with the case where the absolute value |T m1 * | of the basic torque command value T m1 * cannot be regarded as zero, slow down the change of the limit value T m1 * corresponding to the absolute value |T lmt | of the basic torque command value T

[0111] Thus, when the basic torque command value T m1 * is a small value such that it can be regarded as substantially zero, when slowing down the change of the limit value T FB with respect to the feedback torque T lmt , vibrations of the torque transmission system that occur (or remain) when the basic torque command value T m1 * rapidly approaches zero are suppressed. For example, when the accelerator pedal is released or when the shift position is changed from the D range to the N range, torsional vibrations of the vehicle drive system are suppressed. Note that in steady state (scenes where the basic torque command value T m1 * cannot be regarded as substantially zero), while suppressing vibrations of the torque transmission system, generation of noise due to backlash of the gear 12 is suppressed.

[0112] The embodiments of the present invention have been described above. However, the configurations described in the above embodiments, modifications, etc. merely show a part of the application examples of the present invention, and are not intended to limit the technical scope of the present invention.

Description of Reference Numerals

[0113] 10: Rotating electrical machine, 11: Controller, 12: Gear, 13: Driving wheel, 14: Rotation detector, 15: Torque setting unit, 16: Vibration damping control unit, 17: Torque control unit, 21: Addition unit, 22: Rotational speed estimation unit, 23: Subtraction unit, 24: Feedback torque calculation unit, 25: Feedback torque limitation unit, 31: Absolute value calculation unit, 32: Limit value setting unit, 33: Limitation unit, 41: Reference torque calculation unit, 42: Limit value selection unit, 50: Comparison unit, 100: Electric vehicle

Claims

1. A control method for an electric vehicle, which calculates a feedback torque based on a rotational state of a rotating electrical machine, corrects a torque command value based on the feedback torque, and controls the rotating electrical machine according to the corrected torque command value, comprising: setting a limit value for an absolute value of the feedback torque; changing the limit value according to an absolute value of a basic torque command value which is the torque command value before correction by the feedback torque; when at least an absolute value of the basic torque command value can be regarded as zero, making a change in the limit value according to the absolute value of the basic torque command value slower compared with a case where the absolute value of the basic torque command value cannot be regarded as zero; A control method for an electric vehicle.

2. A control method for an electric vehicle according to claim 1, comprising: calculating a reference torque by using an absolute value of the basic torque command value and a transfer characteristic simulating a response from an external torque to the feedback torque; when the absolute value of the basic torque command value cannot be regarded as zero, setting the limit value to the absolute value of the basic torque command value; when the absolute value of the basic torque command value can be regarded as zero, setting the limit value to the reference torque; A control method for an electric vehicle.

3. A control method for an electric vehicle according to claim 1, wherein: when the absolute value of the basic torque command value can be regarded as zero, a change in the limit value when the absolute value of the basic torque command value increases is larger than a change in the limit value when the absolute value of the basic torque command value decreases; A control method for an electric vehicle.

4. A control method for an electric vehicle according to claim 3, comprising: Using the absolute value of the basic torque command value and the transfer characteristics simulating the response from the disturbance torque to the feedback torque, calculate a reference torque. By comparing the absolute value of the basic torque command value with the reference torque, determine whether the absolute value of the basic torque command value increases. When the absolute value of the basic torque command value can be regarded as zero and the absolute value of the basic torque command value decreases, set the limit value to the reference torque. Even when the absolute value of the basic torque command value can be regarded as zero, when the absolute value of the basic torque command value increases, set the limit value to the absolute value of the basic torque command value. A control method for an electric vehicle.

5. A control method for an electric vehicle according to any one of claims 1 to 4, Compare the absolute value of the basic torque command value with a predetermined threshold value. When the absolute value of the basic torque command value is less than or equal to the threshold value, determine that the absolute value of the basic torque command value can be regarded as zero. When the absolute value of the basic torque command value is greater than the threshold value, determine that the absolute value of the basic torque command value cannot be regarded as zero. A control method for an electric vehicle.

6. A control device for an electric vehicle that calculates a feedback torque based on the rotational state of a rotating electrical machine, corrects a torque command value based on the feedback torque, and controls the rotating electrical machine according to the corrected torque command value, Set a limit value for the absolute value of the feedback torque. Change the limit value according to the absolute value of the basic torque command value, which is the torque command value before correction by the feedback torque. When at least the absolute value of the basic torque command value can be regarded as zero, make the change of the limit value according to the absolute value of the basic torque command value slower compared to the case where the absolute value of the basic torque command value cannot be regarded as zero. A control device for an electric vehicle, comprising a feedback torque limiting unit.

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