JP2010288332A - Controller of electric vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To preventing the occurrence of torque vibration while bringing about an effect of vibration damping. <P>SOLUTION: A control block 7h outputs a second torque target value Tm*2 by filtering an output value of a subtractor 7g, namely, a value obtained by subtracting a second term Tm*2_2 of a second torque target value from a first term Tm*2_1 of the second torque target value. In a transfer characteristic Gz (s) of the control block 7h, a numerator quadratic expression of a vehicle identification model (Gp(s)) is used as a numerator, and a quadratic expression having an attenuation coefficient (second attenuation coefficient) ξc (ξz<ξx≤1), which is larger than an attenuation coefficient (first attenuation coefficient) ξz calculated from the numerator of the vehicle identification model and which is set to one or less, is used as a denominator. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a control device for an electric vehicle.

  For example, Patent Document 1 discloses a vehicle control device using an electric motor. In order to perform vibration suppression control, the control device includes a control block having a transfer characteristic of Gp (s), a subtractor for obtaining a deviation between the output of the control block and the motor rotation speed, and H (s) / Gp And (s) a control block having a transfer characteristic. At this time, the difference between the denominator order of H (s) and the numerator order is set to be equal to or greater than the difference between the denominator order of Gp (s) and the numerator order. Thereby, even when the accelerator is depressed from the stopped state or the decelerated state, the vibration control effect can be obtained.

JP 2003-9566 A

  However, according to the technique disclosed in Patent Document 1, when the torsional vibration characteristic of the vehicle to be controlled is the identification model Gp (s), transmission of H (s) / Gp (s) using that characteristic. A torque target value or the like for determining a torque command value for the motor is calculated using a filter having characteristics. Therefore, when the vehicle transfer characteristic deviates from the identification model Gp (s), there is a possibility that vibration occurs in the output torque (feedback torque) according to the resonance characteristic of 1 / Gp (s).

  The present invention has been made in view of such circumstances, and an object thereof is to suppress the generation of torque vibration while achieving a vibration damping effect.

  In order to solve such a problem, in the present invention, the first term computing means performs the second filtering process on the torque command value by performing a first filtering process having a transmission characteristic having a band-pass filter characteristic. The first term of the torque target value is output. In addition, the second term calculation means includes a second filter process comprising a transfer characteristic having a band-pass filter characteristic with respect to the motor rotation speed, and a model of a transfer characteristic between torque input to the vehicle and the motor rotation speed. To output the second term of the second torque target value. The torque target value calculation means is a second torque target value for calculating a torque command value based on a deviation between the first term of the second torque target value and the second term of the second torque target value. Is calculated. In this case, the torque target value calculating means calculates the numerator of the quadratic expression and the quadratic expression for the value obtained by subtracting the second term of the second torque target value from the first term of the second torque target value. Filter means for outputting a second torque target value by performing a third filter process having a transfer characteristic composed of a denominator. Here, the transfer characteristic of the filter means is set to be equal to or less than the first attenuation coefficient calculated from the numerator quadratic expression of the vehicle identification model and calculated from the numerator of the vehicle identification model. A quadratic expression having the second attenuation coefficient is used as the denominator.

  According to the present invention, even when the vehicle transfer characteristics deviate from the identification model, the filter function of the filter means cancels out the vibration of the output torque due to the feedback control. Thus, generation of torque vibration is suppressed while achieving a vibration damping effect.

The block diagram which shows typically the structure of the control apparatus of the electric vehicle which concerns on 1st Embodiment. The block diagram which shows the specific structure of the vibration suppression control part 7 concerning 1st Embodiment. The figure which shows the simulation result at the time of using a vehicle model with a dead hand as real plant Gp '(s). Bode diagram of transfer characteristics H (s) · s × 1 / (s · Gp (s)) as a result of frequency analysis The block diagram which shows the specific structure of the vibration suppression control part 7 concerning 2nd Embodiment. Bode diagram of transfer characteristics H (s) · s × 1 / (s · Gp (s)) as a result of frequency analysis The block diagram which shows the specific structure of the vibration suppression control part 7 concerning 2nd Embodiment. Bode diagram of transfer characteristics H (s) · s × 1 / (s · Gp (s)) as a result of frequency analysis The figure which shows the simulation result at the time of using a vehicle model with a dead hand as real plant Gp '(s). The block diagram which shows the specific structure of the vibration suppression control part 7 concerning 3rd Embodiment. The figure which shows the simulation result at the time of using a vehicle model with a dead hand as real plant Gp '(s). The block diagram which shows the specific structure of the vibration suppression control part 7 concerning 4th Embodiment. Bode diagram of transfer characteristics H (s) · s × 1 / (s · Gp (s)) as a result of frequency analysis Explanatory drawing which shows the simulation result at the time of using a vehicle model with a dead hand as real plant Gp '(s)

(First embodiment)
FIG. 1 is a block diagram schematically showing the configuration of the control apparatus for an electric vehicle according to the first embodiment of the present invention. The electric vehicle according to the present embodiment is equipped with a motor 1 that operates with electric power from a battery (not shown), and an output shaft of the motor 1 is connected to a speed reducer (not shown). The power from the motor 1 is transmitted to the left and right drive wheels 3 and 4 via the speed reducer and the drive shaft 2. An inverter (not shown) is provided between the battery and the motor 1, and the DC power of the battery is supplied to the motor 1 after being converted into AC power by the inverter.

  The electric vehicle is equipped with a control device 5 that controls the output torque of the motor 1. The control device 5 includes a torque setting unit 6, a vibration suppression control unit 7, and a torque control unit 8. Yes. As the control device 5, a microcomputer mainly composed of CPU, ROM, RAM, and I / O interface can be used. Vehicle information detected by various sensors is input to the control device 5 in order to perform torque control. The rotation angle sensor 9 is a sensor that detects the motor rotation speed ωm by detecting the rotation angle of the motor 1. The accelerator opening sensor 10 is a sensor that detects an accelerator operation amount (for example, accelerator opening) by a driver. The rotation angle sensor 9 and the accelerator opening sensor 10 function as detection means for detecting vehicle information.

  The torque setting unit (torque target value setting means) 6 sets the first torque target value Tm * based on the vehicle information, specifically, the detected accelerator operation amount and the motor rotation speed ωm. The set torque target value Tm * is output to the vibration suppression control unit 7. The vibration suppression control unit 7 performs an operation by using the detected motor rotation speed ωm and the torque target value Tm * as inputs, and determines a torque command value T * that is a torque command value for the motor 1. The determined torque command value T * is output to the torque control unit 8. The torque control unit 8 performs control such that the output torque of the motor 1 follows the motor torque command value T * by controlling the inverter using PWM control or the like.

  FIG. 2 is a block diagram illustrating a specific configuration of the vibration suppression control unit 7 according to the first embodiment. In the vibration suppression control unit 7, a first torque target value Tm * and a second torque target value Tm * 2 described later are input to the adder 7a, and the adder 7a adds both values. The adder 7a functions as torque command value calculation means for calculating the torque command value Tm *, and is based on the first torque target value Tm * and the second torque target value Tm * 2. The sum of both values Tm * and Tm * 2 is calculated as the torque command value Tm *. A torque command value T *, which is an output from the adder 7a, is input to the control block 7b.

  Here, as shown in FIG. 1, in the control device 5, a torque command value T * that is an output from the adder 7 a that forms part of the vibration suppression control unit 7 is input to the torque control unit 8. And the torque control part 8 controls the motor 1 via an inverter based on this torque command value T *. When the motor 1 is driven in accordance with this control, the rotation speed ωm of the motor 1 is detected by the rotation angle sensor 9, and the detected motor rotation speed ωm is fed back to the control system.

  In the block diagram shown in FIG. 2, the control block 7 b has a transfer characteristic of Gp ′ (s), and the actual plant as the motor 1 on the electric vehicle controlled by the torque control unit 8 through the inverter. It represents instead. The control block 7b receives the torque command value T * as an input and outputs the motor rotation speed of the motor 1 that is the actual plant Gp ′ (s). In order to reflect the torque disturbance element entering the actual plant Gp ′ (s), the torque command value T * output from the adder 7a is added to the torque disturbance element Td by the adder 7c. 7b. Further, the motor rotational speed disturbance element ωd is added by the adder 7d to the motor rotational speed output from the control block 7b in order to reflect the motor rotational speed disturbance element entering the actual plant Gp ′ (s). The output (motor rotational speed) from the adder 7d corresponds to the motor rotational speed ωm detected by the rotational angle sensor 9. The motor rotation speed ωm output from the adder 7d is input to the control block 7e.

  The control block 7e functions as a filter, and this filter has a transfer characteristic of H (s) / Gp (s). Here, H (s) has a characteristic as a band-pass filter, and Gp (s) is a model of a transmission characteristic between a torque input to the vehicle and a motor rotation speed (an identification model of a vehicle transmission characteristic (vehicle Identification model)). This control block 7e receives (rotates) the second term Tm * 2_2 of the second torque target value by applying the filter processing to the motor rotational speed ωm (second term computing means). The second term Tm * 2_2 of the second torque target value is output to the subtractor 7g.

  On the other hand, the torque command value T * output from the adder 7a is also input to the control block 7f in addition to the control block 7b. The control block 7f functions as a bandpass filter and has the above-described transfer characteristic of H (s). The control block 7f receives the torque command value T * and performs filtering on it to output (calculate) the first term Tm * 2_1 of the second torque target value (first term computing means). . The first term Tm * 2_1 of the second torque target value is output to the subtractor 7g.

  The subtractor 7g subtracts the second term Tm * 2_2 of the second torque target value from the first term Tm * 2_1 of the second torque target value to thereby obtain a deviation between the two values Tm * 2_1 and Tm * 2_2. Is calculated. The deviation of the first term Tm * 2_1 and the second term Tm * 2_2 of the second torque target value, which is the output from the subtractor 7g, is output to the control block 7h.

  The control block 7h functions as a filter, and this filter has a transfer characteristic of Gz (s). Details of the transfer characteristic Gz (s) will be described later. The control block 7h receives the output value from the subtractor 7g and performs a filtering process on the input value, thereby outputting a second torque target value Tm * 2 (filter means). The calculated second torque target value Tm * 2 is output to the adder 7a as described above. That is, the subtractor 7g and the control block 7h described above are based on the deviation between the first term Tm * 2_1 of the second torque target value and the second term Tm * 2_2 of the second torque target value. It functions as a torque target value calculation means for calculating the torque target value Tm * 2.

  One of the features of the present embodiment is that, based on the system configuration of the vibration suppression control unit 7, between the transfer characteristic model Gp (s) in the control block 7 e and the actual plant Gp ′ (s). When the deviation occurs or when the motor rotation speed disturbance element ωd occurs, the occurrence of vibration in the output torque is suppressed.

Hereinafter, a method for setting a filter having the transfer characteristic Gz (s), which is one of the features of the present embodiment, will be described. The transfer characteristic Gz (s) is set due to the transfer characteristic model Gp (s). Therefore, the transfer characteristic model Gp (s) will be described. The following equation can be derived as the equation of motion of the drive torsional vibration system.

  In Formula 1, “*” attached to the upper right of the sign represents time differentiation. Jm is the inertia of the motor 1, Jw is the inertia of the drive wheel, and M is the mass of the vehicle. KD is the torsional rigidity of the drive system, KT is a coefficient relating to the friction between the tire and the road surface, N is the overall gear ratio, and r is the load radius of the tire. ωm is the motor rotation speed, Tm is the torque of the motor 1, and TD is the torque of the drive wheels. Further, F is the force applied to the vehicle, V is the vehicle speed, and ωw is the rotational speed of the drive wheels.

When a model Gp (s) of transfer characteristics from the motor torque to the motor rotation speed is obtained based on the above equation of motion, Gp (s) is expressed by the following equation.

Here, each parameter in Formula 2 is represented by the following formula.

When the poles and zeros of the transfer function shown in Formula 2 are examined, one pole and one zero show extremely close values. This is equivalent to the fact that α and β shown in the following expression show extremely close values.

By performing pole-zero cancellation in Formula 4 (approximate α = β), Gp (s) constitutes a (second order) / (third order) transfer characteristic, as shown in the following expression.

In the present embodiment, attention is paid to a numerator term of the same formula. When each second-order coefficient in this numerator is A (second-order coefficient), B (first-order coefficient), and C (zero-order coefficient), these coefficients are expressed by the following equation between the attenuation coefficient ζz. It holds.

From the equation, the attenuation coefficient ζz can be expressed by the following equation.

By calculating the attenuation coefficient ζz from Equation 7, the coefficient ζc is determined to be a value larger than the calculated value ζz and in the range of 1 or less (ζz <ζc ≦ 1). Based on this coefficient ζc, Gz (s) is calculated from the following equation.

  In the present embodiment, when the control block 7h having a filter having the transfer characteristic Gz (s) is provided, when a divergence occurs between the transfer characteristic model Gp (s) and the actual plant Gp ′ (s), Thus, it is possible to suppress the vibration of the output torque when the motor rotation speed disturbance ωd occurs.

  FIG. 3 is a diagram showing a simulation result when a vehicle model with a dead hand having a dead zone of ± 10 Nm in the transmission torque of the drive shaft is used as the actual plant Gp ′ (s). In the figure, (a) shows the transition of the output torque Tf, (b) shows the transition of the motor rotation speed ωm, and (c) shows the transition of the transmission torque Td of the drive shaft. The figure shows a simulation result at the start for a torque step command St from 0 Nm to 150 Nm. Here, in each parameter Tf, ωm, Td, the one with the subscript “c” is the simulation result when the present control method using the filter having the transfer characteristic Gz (s) is applied, and the subscript “i”. "Is a simulation result when this control method is not applied. Further, in the case where this control method is applied, 1 is set as the coefficient ζc described above.

  As can be seen from the figure, when this control method is not applied, the output torque Tfi and the drive shaft transmission torque Tdi continue to vibrate at about 1.3 Hz. On the other hand, when this control method is applied, it can be seen that vibration of about 1.3 Hz in the output torque Tfc is suppressed. By adding this control block 7h (filter having a transfer characteristic Gz (s)), the vibration damping effect at the frequency to be controlled is reduced, and vibration of about 3.8 Hz is applied to the drive shaft transmission torque Tdc and the rotational speed ωmc. It has appeared.

  As described above, in the present embodiment, the control block 7h including a filter composed of the transfer characteristic Gz (s) composed of the quadratic numerator and the quadratic denominator is added. The control block 7h filters the output value of the subtractor 7g, that is, a value obtained by subtracting the second term Tm * 2_1 of the second torque target value from the first term Tm * 2_1 of the second torque target value. By performing the processing, the second torque target value Tm * 2 is output. Here, the transfer characteristic Gz (s) in the control block 7h uses a numerator quadratic expression of the vehicle identification model (Gp (s)) as a numerator, and an attenuation coefficient (first value) calculated from the numerator of the vehicle identification model. The quadratic expression having an attenuation coefficient (second attenuation coefficient) ζc (ζz <ζx ≦ 1) that is larger than (attenuation coefficient) ζz and set to 1 or less is used as a denominator.

  According to such a configuration, even when the vehicle transfer characteristic deviates from the identification model Gp (s), it is canceled by the filter function of the control block 7h, so that the vibration of the output torque due to the feedback control can be suppressed. Thus, generation of torque vibration is suppressed while achieving a vibration damping effect.

(Second Embodiment)
Hereinafter, the control device 5 for the electric vehicle according to the second embodiment of the present invention will be described. The control device 5 of the present embodiment is different from the first embodiment in the control method by the vibration suppression control unit 7. The description of the configuration common to the first embodiment will be omitted, and the following description will be focused on the differences.

  FIG. 4 is a Bode diagram of the transfer characteristics H (s) · s × 1 / (s · Gp (s)) as a result of the frequency analysis. Here, the transfer characteristic H (s) · s × 1 / (s · Gp (s)) is an equivalent conversion of the transfer characteristic H (s) / Gp (s). In the same figure, (a) is a figure which shows the gain Ga corresponding to the frequency F, (b) is a figure which shows the phase Ph corresponding to the frequency F. Moreover, (c) is a figure which expands and shows a part of (a), (d) is a figure which expands and shows a part of (b). Here, in each of the parameters Ga and Ph, those with the subscript “c” are simulation results when the control method of the first embodiment is applied, and those with the subscript “i” are It is a simulation result when not applying the control method of a 1st embodiment. Further, in the case of applying the control method of the first embodiment, 1 is set as the coefficient ζc described above.

  As can be seen from the figure, by adding a control block 7e (filter having a transfer characteristic Gz (s)), compared to a case where this is not added, at a control target frequency (F = 3.85 Hz), −1 A gain difference of .9 dB is generated, and a phase difference of 33 deg is generated. One of the features of this embodiment is to correct this phase difference. Here, the phase difference to be corrected is γ. In the present embodiment, phase compensation is performed on the phase difference γ by adding a phase compensator 7i as shown in FIG.

FIG. 5 is a block diagram illustrating a specific configuration of the vibration suppression control unit 7 according to the second embodiment. The phase compensator (phase compensation means) 7i receives the output value (second torque target value Tm * 2) from the control block 7h, controls the phase of an arbitrary period, and controls the phase controlled second phase. Torque target value Tm * 2 is output. The output second torque target value Tm * 2 is output to the adder 7a as described above. Here, the phase compensator 7i has, for example, a transfer characteristic Gzn (s) expressed by the following equation (where T1 and T2 are phase compensation constants).

  FIG. 6 is a Bode diagram of transfer characteristics H (s) · s × 1 / (s · Gp (s)) as a result of frequency analysis. In the same figure, (a) is a figure which shows the gain Ga corresponding to the frequency F, (b) is a figure which shows the phase Ph corresponding to the frequency F. Moreover, (c) is a figure which expands and shows a part of (a), (d) is a figure which expands and shows a part of (b). Here, in each of the parameters Ga and Ph, the one with the subscript “c” is a simulation result when the present control method in which the control block 7 h and the phase compensator 7 i are added is applied, and the subscript “i”. The ones with are simulation results when this control method is not applied. In the case where this control method is applied, the phase compensator 7i delays the phase by 33 degrees at the control target frequency (F = 3.85 Hz), and ζc is set to 1. As can be seen from FIG. 9D, it is understood that the phase difference at the control target frequency (F = 3.85 Hz) can be corrected by this control method. Note that, due to the phase compensation by the phase compensator 7i, the deviation of the gain Ga at the control target frequency is −7.19 dB.

  FIG. 7 is a block diagram illustrating a specific configuration of the vibration suppression control unit 7 according to the second embodiment. In this embodiment, in order to correct the gain difference, a block (gain compensation means) 7j having a gain K is further added after the phase compensator 7i. Then, by adjusting the gain K, the gain difference at the control target frequency is compensated.

  FIG. 8 is a Bode diagram of the transfer characteristic H (s) · s × 1 / (s · Gp (s)) as a result of the frequency analysis. In the parameters Ga and Ph shown in the figure, the suffix “c” is the simulation result when the present control method is applied in which the control block 7h, the phase compensator 7i and the gain K block 7j are added. Yes, the one with the suffix “i” is a simulation result when this control method is not applied. In the case of applying this control method, the phase compensator 7i delays the phase by 33 degrees at the control target frequency of 3.85 Hz, and ζc is set to 1. As can be seen from the figure, the gain difference at the control target frequency (F = 3.85 Hz) is suppressed by the addition of the gain K.

  FIG. 9 is an explanatory diagram showing a simulation result when a vehicle model with a dead hand having a dead zone of ± 10 Nm in the transmission torque of the drive shaft is used as the actual plant Gp ′ (s). In the figure, (a) shows the transition of the output torque Tf, and (b) shows the transition of the motor rotational speed ωm. (C) is an enlarged view of region A in (b), and (d) shows the transition of the transmission torque Td of the drive shaft. The figure shows a simulation result at the start for a torque step command St from 0 Nm to 150 Nm. Here, in each parameter Tf, ωm, Td, the one with the subscript “c” is the simulation result when the present control method is applied, and the one with the subscript “i” is the present control method. It is a simulation result when not applying.

  As can be seen from the figure, when the present control method is applied, the vibrations of the output torque Tfc, the drive shaft transmission torque Tdc, and the motor rotation speed ωmc are suppressed as compared with the case where the present control method is not applied. Yes.

  Thus, in this embodiment, the phase compensator 7i for correcting the phase at the control target frequency is added to the subsequent stage of the control block 7h. The phase compensator 7i performs phase compensation on the second torque target value Tm * 2 filtered by the control block 7h. According to such a configuration, it is possible to improve the vibration suppression effect while suppressing the vibration of the output torque.

  In the present embodiment, a block 7j having a gain K for correcting the gain at the control target frequency is added after the control block 7h. This block 7j performs gain compensation on the second torque target value Tm * 2 filtered by the control block 7h. According to such a configuration, it is possible to further improve the vibration suppression effect while suppressing the vibration of the output torque.

(Third embodiment)
Hereinafter, the control device 5 for the electric vehicle according to the third embodiment of the present invention will be described. The control device 5 of the present embodiment is different from the first embodiment in the control method by the vibration suppression control unit 7. The description of the configuration common to the first embodiment will be omitted, and the following description will be focused on the differences.

  FIG. 10 is a block diagram illustrating a specific configuration of the vibration suppression control unit 7 according to the third embodiment. In this embodiment, the control block 7h as a filter having the transfer characteristic Gz (s) is applied only to the actual output torque. The control block 7f for calculating the first term Tm * 2_1 of the second torque target value is obtained by adding the first torque target value Tm * and the output value of the subtractor 7g by the adder 7k. It is input with.

  FIG. 11 is an explanatory diagram showing a simulation result when a vehicle model with a dead hand having a dead zone of ± 10 Nm in the transmission torque of the drive shaft is used as the actual plant Gp ′ (s). In the figure, (a) shows the transition of the output torque Tf, and (b) shows the transition of the motor rotational speed ωm. (C) is an enlarged view of region A in (b), and (d) shows the transition of the transmission torque Td of the drive shaft. The figure shows a simulation result at the start for a torque step command St from 0 Nm to 150 Nm. Here, in each of the parameters Tf, ωm, and Td, the suffix “c” is a simulation result according to this control method in which the filter (transfer characteristic Gz (s)) is applied only to the actual output torque. The one with the subscript “i” is a simulation result when this control method is not applied.

  As can be seen from the figure, the vibrations of the output torque Tfc, the drive shaft transmission torque Tdc, and the motor rotational speed ωmc are suppressed as compared with the case where this control method is not applied.

  As described above, in the present embodiment, the control block 7f adds the first term Tm * 2_1 of the second torque target value and the second torque target to the first torque target value Tm * set by the torque setting unit 6. The first term Tm * 2_1 of the second torque target value is calculated based on the added value obtained by adding the difference between the value and the second term Tm * 2_2. According to this configuration, the control block 7h (filter for the transfer characteristic Gz (s)) is used only for the calculation of the torque command value T *, and the input value to the control block 7h is used for the calculation of the feedback control system. It becomes. Thereby, it is possible to further improve the vibration suppression effect while suppressing the vibration of the output torque.

  Note that although the present embodiment has been described based on the configuration of the first embodiment, the present control method may be applied to the configuration of the second embodiment.

(Fourth embodiment)
Hereinafter, a control device 5 for an electric vehicle according to a fourth embodiment of the present invention will be described. The control device 5 of the present embodiment is different from the first embodiment in the control method by the vibration suppression control unit 7. The description of the configuration common to the first embodiment will be omitted, and the following description will be focused on the differences.

  FIG. 12 is a block diagram illustrating a specific configuration of the vibration suppression control unit 7 according to the fourth embodiment. One of the features of the present embodiment is that the phase difference γ by adding the control block 7h (filter for the transfer characteristic Gz (s)), the transfer characteristic H (s) in the control blocks 7e and 7f, and the transfer characteristic H ′. It is to perform phase compensation by replacing with (s). In the figure, control blocks 7e and 7f in which the transfer characteristic H (s) is replaced by the transfer characteristic H '(s) are shown as control blocks 7e' and 7f '.

  In the first embodiment, the center frequency of the bandpass filter, which is the transfer characteristic H (s), is matched with the torsional resonance frequency of the vehicle drive system. In this embodiment, phase compensation for the phase difference γ is performed by using the transfer characteristic H ′ (s) obtained by shifting the center frequency of the transfer characteristic H (s) by a predetermined frequency.

When the band-pass filter is composed of a first-order high-pass filter and a low-pass filter, the transfer function is expressed by the following equation.

  Here, ωc is a parameter corresponding to the center frequency fc after phase compensation when the torsional resonance frequency is fp (fp (Hz) = ωp (rad / s) / 2π) (fc (Hz) = ωc (Rad / s) / 2π).

Here, when j × ωp is substituted for “s” on the right side of Equation 7, the right side becomes the following equation.

In the right side shown in Formula 11, the right side can be transformed into the following formula by integrating the denominator with both of the numerator denominator.

Here, when the right side shown in Expression 12 is replaced with C + D · j, tan γ satisfies the following expression.

Equation 13 can be modified as shown in the following equation.

From Expression 14, ωc satisfies the relationship of the following expression.

  Accordingly, the center frequency fc ′ of the transfer function H ′ (s) can be calculated based on ωc shown in Expression 12 (fc (Hz) = ωc (rad / s) / 2π). At this time, the transfer characteristic H ′ (s) is set so as to correct the above-described gain shift.

  FIG. 13 is a Bode diagram of transfer characteristics H (s) · s × 1 / (s · Gp (s)) as a result of frequency analysis. In the same figure, (a) is a figure which shows the gain Ga corresponding to the frequency F, (b) is a figure which shows the phase Ph corresponding to the frequency F. Moreover, (c) is a figure which expands and shows a part of (a), (d) is a figure which expands and shows a part of (b). Here, in each of the parameters Ga and Ph, those with the subscript “c” are added to the control block 7h and the simulation according to the present control method in which the transfer function H (s) is replaced with the transfer function H ′ (s). The result, with the subscript “i”, is the simulation result when this control method is not applied. Further, in the case where this control method is applied, 1 is set as the above-described ζc. As can be seen from FIG. 6D, it is understood that the phase difference and gain difference at the control target frequency (F = 3.85 Hz) can be corrected by this control method.

  FIG. 14 is an explanatory diagram showing a simulation result when a vehicle model with a dead hand having a dead zone of ± 10 Nm in the transmission torque of the drive shaft is used as the actual plant Gp ′ (s). In the figure, (a) shows the transition of the output torque Tf, and (b) shows the transition of the motor rotational speed ωm. (C) is an enlarged view of region A in (b), and (d) shows the transition of the transmission torque Td of the drive shaft. The figure shows a simulation result at the start for a torque step command St from 0 Nm to 150 Nm. Here, in each parameter Tf, ωm, Td, the one with the subscript “c” is the simulation result when the present control method is applied, and the one with the subscript “i” is the present control method. It is a simulation result when not applying.

  As can be seen from the figure, the vibrations of the output torque Tfc, the drive shaft transmission torque Tdc, and the motor rotational speed ωmc are suppressed as compared with the case where this control method is not applied.

  As described above, in the present embodiment, the control block 7f ′ and the control block 7e ′ change the frequency characteristic (center frequency fc) in the transfer characteristic H (s) having the characteristics of the bandpass filter (H ′ ( s), fc ′), the phase at the control target frequency is corrected. According to such a configuration, it is possible to further improve the vibration suppression effect while suppressing the vibration of the output torque.

DESCRIPTION OF SYMBOLS 1 ... Motor 2 ... Drive shaft 3, 4 ... Drive wheel 5 ... Control apparatus 6 ... Torque setting part 7 ... Damping control part 7a ... Adder 7b ... Control block 7c ... Adder 7d ... Adder 7e ... Control block 7f ... Control block 7g ... Subtractor 7h ... Control block 7i ... Phase compensator 7j ... Block 8 ... Torque control unit 9 ... Rotation angle sensor 10 ... Accelerator opening sensor

Claims (6)

In a control device for an electric vehicle using an electric motor driven as a power source based on a torque command value,
Detecting means for detecting vehicle information;
Torque target value setting means for setting a first torque target value based on the vehicle information;
Torque command value calculation means for calculating a torque command value for the electric motor;
A first term computing means for computing a first term of a second torque target value by applying a first filter process comprising a transfer characteristic having a bandpass filter characteristic to the torque command value;
A second characteristic comprising a transmission characteristic having the characteristics of the bandpass filter with respect to a motor rotational speed which is one of the vehicle information, and a vehicle identification model of a transmission characteristic between torque input to the vehicle and the motor rotational speed A second term computing means for computing a second term of the second torque target value by performing a filtering process;
A torque target value calculation means for calculating a second torque target value based on a deviation between the first term of the second torque target value and the second term of the second torque target value;
The vehicle identification model is composed of a quadratic numerator and a cubic denominator,
The torque target value calculation means includes:
Subtracting means for subtracting the second term of the second torque target value from the first term of the second torque target value;
The second torque target value is output by subjecting the output value of the subtracting means to a third filtering process comprising a transfer characteristic composed of a quadratic numerator and a quadratic denominator. Filter means,
The transfer characteristic of the filter means is set to a numerator quadratic expression of the vehicle identification model, larger than a first attenuation coefficient calculated from the numerator of the vehicle identification model, and set to 1 or less. A quadratic equation having a second attenuation coefficient is used as a denominator,
The torque command value calculating means calculates the torque command value based on the first torque target value and the second torque target value filtered by the filter means. Vehicle control device. The first damping coefficient ζz is obtained from a relational expression of B / A = 2 · √ (C / A) · ζz when the numerator quadratic expression of the vehicle identification model is expressed as A · s ² + B · s + C. ,
When the second damping coefficient ζc is determined as a constant in the range of ζz <ζc ≦ 1, the filter means has a transfer characteristic satisfying the relationship of the following equation: Gz = [A · s ² + B · s + C] / [ s ² + (2 · √ (C / A) · ζc) · s + (C / A)]
The control apparatus for an electric vehicle according to claim 1. It further has phase compensation means for correcting the phase at the frequency to be controlled,
3. The electric vehicle control device according to claim 1, wherein the phase compensation unit performs phase compensation on the second torque target value filtered by the filter unit. 4. It further has a gain compensation means for correcting the gain at the frequency to be controlled,
4. The control apparatus for an electric vehicle according to claim 3, wherein the gain compensation means performs gain compensation on the second torque target value filtered by the filter means.   The first term calculation means adds the first term of the second torque target value and the second term of the second torque target value to the first torque target value set by the torque target value setting means. 5. The control device for an electric vehicle according to claim 1, wherein the first term of the second torque target value is calculated based on an added value obtained by adding the difference between the first and second torque target values.   The first term calculating means and the second term calculating means correct a phase at the control target frequency by making a frequency characteristic variable in a transfer characteristic having the characteristics of the bandpass filter. Item 3. The control device for an electric vehicle according to item 1 or 2.

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