WO2014057946A1

WO2014057946A1 - Motor control device for electric vehicle and motor control method for electric vehicle

Info

Publication number: WO2014057946A1
Application number: PCT/JP2013/077371
Authority: WO
Inventors: 澤田　彰; 伊藤　健; 中島　孝; 雄史勝又; 翔大野; 弘征小松
Original assignee: 日産自動車株式会社
Priority date: 2012-10-09
Filing date: 2013-10-08
Publication date: 2014-04-17

Abstract

Disclosed is a motor control device for electric vehicles that controls the torque of a motor connected to drive wheels by setting a motor torque command value on the basis of vehicle information, wherein the motor control device comprises: a damping control unit that executes, with respect to the motor torque command value, damping control for suppressing vehicle vibration; a motor torque control unit that controls the motor torque in accordance with the motor torque command value that has been subjected to said damping control; and a parking-lock release determination unit that determines whether or not a parking-locked state, in which the wheels are locked from rotating, is released. When said parking-locked state is released, the damping control unit executes damping control using a control constant calculated from a vehicle model in a wheel-locked state.

Description

Motor control device for electric vehicle and motor control method for electric vehicle

The present invention relates to a motor control device for an electric vehicle and a motor control method for the electric vehicle.

In the vibration suppression control device for a vehicle described in JP2003-9566A, a torque target value for controlling a motor is calculated by the following method. First, a drive torque target value is calculated by performing a filtering process for removing or reducing the natural vibration frequency component of the vehicle torque transmission system on the drive torque request value of the drive motor calculated from the accelerator opening and the vehicle speed. . Subsequently, the motor rotation speed estimation value is calculated from the drive torque target value in consideration of the motor characteristic model, and the deviation between the calculated motor rotation speed estimation value and the actual motor rotation speed is calculated as the natural vibration frequency of the driving force transmission system. A torque command value is calculated by passing through a filter constituted by an inverse system of a band pass filter and a motor characteristic model as a center frequency. Then, the final drive torque target value is calculated by adding the calculated torque command value to the drive torque target value. This eliminates the effects of road gradients, torque transmission system disturbances, motor characteristic model errors, etc., and also eliminates or reduces the natural vibration frequency component of the vehicle torque transmission system, thereby reducing the damping effect and steep torque. Can be achieved at the same time.

Suppose here that the parking range (P range) is set on the uphill road and the vehicle stops without applying the foot brake or parking brake. In this case, by setting to the P range, the park lock mechanism that locks and rotates the wheel operates, and the vehicle can be stopped even if the brake is released. However, at this time, since the wheels are not fixed, the drive shaft is twisted by a predetermined amount according to the gradient and stopped. In order to start the vehicle from such a stopping situation, it is necessary to release the P range by stepping on the brake. At this time, by releasing the P range, the parking lock mechanism is released, and the torsion accumulated in the drive shaft is released, which causes a rattling vibration, and the occupant feels a sudden shock, anxiety and I feel uncomfortable. Hereinafter, this vibration / shock is expressed as a park lock release shock.

In the vehicle vibration damping control device described in JP2003-9566A, the configuration of the above feature can suppress the vibration component of the drive system such as the drive shaft with respect to the motor rotation speed by feedback processing. Can also be reduced.

By the way, in the vehicle vibration damping control device described in JP2003-9566A, the natural vibration frequency component of the vehicle torque transmission is calculated from a vehicle model that considers the wheels. The wheel at the time of releasing the park lock is fixed because the brake is grasped. Strictly speaking, considering the wheel in the vehicle model, an error occurs in the vehicle model when the parking lock is released. Therefore, when the vibration suppression control described in JP2003-9566A is applied as it is as the vibration suppression control at the time of releasing the park lock, torque overshoot occurs, the convergence of the park lock release shock is delayed, and there is a park lock release shock. . In addition, since the gear fluctuation crosses the backlash section, a tooth contact sound is generated due to the backlash, which may cause anxiety and discomfort to the driver.

The object of the present invention is to suppress vibrations that occur when parking lock is released.

The motor control apparatus for an electric vehicle according to an embodiment calculates the vibration control for suppressing the vehicle vibration with respect to the motor torque command value, and calculates the vehicle lock state from the vehicle model when the park lock state is released. Performs vibration suppression control using control constants.

Embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 is a block diagram illustrating a main configuration of an electric vehicle including a motor control device for an electric vehicle according to the first embodiment. FIG. 2 is a flowchart showing a flow of processing of motor current control performed by the electric motor controller. FIG. 3 is a diagram showing an example of an accelerator opening-torque table. FIG. 4 is a control block diagram of the vibration suppression control calculation process in the first embodiment. FIG. 5 is a diagram modeling a vehicle driving force transmission system in a wheel lock state. FIG. 6 is a flowchart of the vibration suppression control calculation process in the first embodiment. FIG. 7 is a control block diagram of a vibration suppression control calculation process at the time of park lock release in the second embodiment. FIG. 8 is a flowchart of the vibration suppression control calculation process in the second embodiment. FIG. 9 is a diagram illustrating an example of a control result by the motor control device of the electric vehicle according to the first and second embodiments.

-First embodiment-
FIG. 1 is a block diagram illustrating a main configuration of an electric vehicle including a motor control device for an electric vehicle according to the first embodiment. The motor control device for an electric vehicle according to the present invention includes an electric motor as a part or all of the drive source of the vehicle, and can be applied to an electric vehicle that can run by the driving force of the electric motor. It can be applied to automobiles and fuel cell vehicles.

The electric motor controller 2 uses, as digital signals, signals indicating the vehicle state such as the vehicle speed V, the accelerator opening APO, the rotor phase θre of the electric motor (three-phase AC motor) 4, and the currents iu, iv, iw of the electric motor 4. Based on the input signal, a PWM signal for controlling the electric motor 4 is generated. Further, a drive signal for the inverter 3 is generated according to the generated PWM signal.

The inverter 3 includes, for example, two switching elements (for example, power semiconductor elements such as IGBTs and MOS-FETs) for each phase. The supplied direct current is converted into alternating current, and a desired current is passed through the electric motor 4.

The electric motor 4 generates a driving force by the alternating current supplied from the inverter 3, and transmits the driving force to the left and right driving wheels 9 a and 9 b via the speed reducer 5 and the drive shaft 8. Further, when the vehicle is driven and rotated by the drive wheels 9a and 9b, the kinetic energy of the vehicle is recovered as electric energy by generating a regenerative driving force. In this case, the inverter 3 converts an alternating current generated during the regenerative operation of the electric motor 4 into a direct current and supplies the direct current to the battery 1.

The current sensor 7 detects the three-phase alternating currents iu, iv, iw flowing through the electric motor 4. However, since the sum of the three-phase alternating currents iu, iv, and iw is 0, any two-phase current may be detected, and the remaining one-phase current may be obtained by calculation.

The rotation sensor 6 is, for example, a resolver or an encoder, and detects the rotor phase θre of the electric motor 4.

FIG. 2 is a flowchart showing a process flow of motor current control performed by the electric motor controller 2.

In step S201, a signal indicating the vehicle state is input. Here, the vehicle speed V (km / h), the accelerator opening APO (%), the rotor phase θre (rad) of the electric motor 4, the rotational speed Nm (rpm) of the electric motor 4, and the three-phase AC flowing through the electric motor 4 Currents iu, iv, iw, a DC voltage value Vdc (V) between the battery 1 and the inverter 3, and a park lock-related signal to be described later are input.

The rotor phase θre (rad) of the electric motor 4 is acquired from the rotation sensor 6. The rotor angular velocity ωre (rad / s) is obtained by differentiating the rotor phase θre.

The rotational speed Nm (rpm) of the electric motor 4 is obtained by dividing the rotor angular speed ωre (electrical angle) by the number of pole pairs of the electric motor 4 to obtain the rotor mechanical angular speed ωm (rad / s) is obtained by multiplying the obtained rotor mechanical angular velocity ωm by 60 / (2π).

The vehicle speed V (km / h) is acquired by communication from another controller such as a vehicle speed sensor (not shown) or a brake controller (not shown). Alternatively, the rotor mechanical angular speed ωm is multiplied by the tire dynamic radius R, and the vehicle speed v (m / s) is obtained by dividing by the gear ratio of the final gear, and unit conversion is performed by multiplying by 3600/1000 to obtain the vehicle speed. V (km / h) is obtained.

Accelerator opening APO (%) is acquired from an accelerator opening sensor (not shown), or is acquired by communication from another controller such as a vehicle controller (not shown).

The currents iu, iv, iw (A) flowing through the electric motor 4 are acquired from the current sensor 7.

DC voltage value Vdc (V) is obtained from a voltage sensor (not shown) provided on a DC power supply line between battery 1 and inverter 3 or a power supply voltage value transmitted from a battery controller (not shown).

In step S202, a drive torque target value Tm ^* , which is a basic target torque command value, is set. Specifically, the drive torque target value Tm ^* is set by referring to the accelerator opening-torque table shown in FIG. 3 based on the accelerator opening APO, the vehicle speed V, and the shift position input in step S201. To do. When the shift position is N or P, the drive torque target value Tm ^* is 0 Nm.

In step S203, vibration suppression control calculation processing is performed. More specifically, on the basis of the drive torque target value Tm ^* set in step S202 and the motor rotation speed ωm, the vibration of the drive force transmission system (drive shaft vibration) can be achieved without sacrificing the response of the drive shaft torque. The final torque target value Tmfin ^* that suppresses torsional vibration and the like is calculated.

In the present embodiment, when the parking lock is released, vibration suppression control is performed using the control constant calculated from the vehicle model in the wheel locked state. When the parking lock is not released, the control constant calculated from the vehicle model not in the wheel locked state is used. Vibration suppression control using is performed. A detailed calculation method of the final torque target value Tmfin ^* will be described later.

In step S204, the d-axis current target value id ^* and the q-axis current target value iq ^* are obtained based on the final torque target value Tmfin ^* , the electric motor rotation speed ωm, and the DC voltage value Vdc calculated in step S203.

In step S205, current control is performed to match the d-axis current id and the q-axis current iq with the d-axis current target value id ^* and the q-axis current target value iq ^* obtained in step S204, respectively. For this reason, first, the d-axis current id and the q-axis current iq are obtained based on the three-phase AC current values iu, iv, iw input in step S201 and the rotor phase θre of the electric motor 4. Subsequently, d-axis and q-axis voltage command values vd and vq are calculated from deviations between the d-axis and q-axis current target values id ^* and iq ^* and the d-axis and q-axis currents id and iq.

Next, three-phase AC voltage command values vu, vv, vw are obtained from the d-axis and q-axis voltage command values vd, vq and the electric motor rotation speed ωm. Then, PWM signals tu (%), tv (%), and tw (%) are obtained from the obtained three-phase AC voltage command values vu, vv, and vw and the DC voltage value Vdc. The electric motor 4 can be driven with a desired torque indicated by the drive torque target value Tm ^* by opening and closing the switching element of the inverter 3 by the PWM signals tu, tv, and tw thus obtained.

Details of the vibration suppression control calculation process performed in step S203 of FIG. 2 will be described. As described above, in the present embodiment, when the parking lock is released, vibration suppression control is performed using the control constant calculated from the vehicle model in the wheel locked state, and when the parking lock is not released, the vehicle model is not in the wheel locked state. Vibration suppression control using the control constant calculated from the above is performed. The method of damping control during normal driving other than when the park lock is released is the same as the damping control method described in JP2003-9566A.

FIG. 4 is a control block diagram of vibration suppression control calculation processing. The vibration suppression control calculation process is performed by the F / F compensator 41, the F / B compensator 42, and the adder 43.

The F / F compensator 41 includes a control block 401 having a transfer characteristic of Gm (s) / Gp (s). Gp (s) is a vehicle model showing a transmission characteristic between torque input to the vehicle and the motor rotational speed, and Gm (s) is between the torque input to the vehicle and the response target of the motor rotational speed. It is an ideal model showing transfer characteristics. The F / F compensator 41 is a filter that reduces a natural vibration frequency component of the torque transmission system of the vehicle. The F / F compensator 41 receives the drive torque target value Tm ^* and outputs the first torque target value Tm1 ^* .

The F / B compensator 42 includes a control block 402 representing the vehicle model Gp (s), a control block 403 having a transfer characteristic of H (s) / Gp (s), and a subtractor 404. The control block 402 inputs the final torque target value Tmfin ^* and outputs a motor rotation speed estimated value. The subtractor 404 obtains a deviation between the estimated motor speed value calculated by the control block 402 and the detected motor speed value ωm. The deviation between the estimated motor speed value and the detected motor speed value ωm is input to the control block 403, and the output of the control block 403 is multiplied by the F / B gain k to obtain the second torque target value Tm2 ^*. Calculated. H (s) has the characteristics of a bandpass filter whose center frequency matches the torsional resonance frequency of the vehicle drive system. The F / B compensator 42 functions as a disturbance suppression filter based on the deviation between the estimated value of the motor speed and the detected value of the motor speed.

The adder 43 adds the first torque target value Tm1 ^* output from the F / F compensator 41 and the second torque target value Tm2 ^* output from the F / B compensator 42 to obtain a final value. Obtain the torque target value Tmfin ^* .

The vibration suppression control calculation processing according to the control block diagram shown in FIG. 4 is common during normal driving other than when the parking lock is released, and when the parking lock is released, details of which are described in JP2003-9566A. Are listed. In the present embodiment, in the vibration suppression control during normal travel other than when the parking lock is released, the control constant calculated as Gp (s) is used as the vehicle model, and in the vibration suppression control when the parking lock is released, the vehicle is locked. The control constant calculated as the vehicle model Gpl (s) is used. Since the calculation method of the vehicle model Gp (s) is described in detail in JP2003-9566A, a detailed description of the calculation method is omitted here.

The transfer characteristic Gpl (s) from the drive torque target value Tm ^* to the motor rotational speed ωm will be described. FIG. 5 is a diagram modeling a vehicle driving force transmission system in a wheel lock state, and a vehicle motion equation is expressed by the following equations (1) to (3).

Here, each parameter in the equations (1) to (3) is as follows.
Jm: Motor inertia Kd: Torsional rigidity of drive shaft N: Overall gear ratio ωm: Motor angular speed Tm: Motor torque Td: Drive shaft torque θ: Torsion angle of drive shaft

Expressions (4) and (5) are obtained when Laplace conversion is performed on Expressions (1) to (3) to obtain transfer characteristics from the drive torque target value Tm ^* to the motor angular velocity ωm.

However, ω _pl in the equation (5) is expressed by the following equation (6).

Next, the vibration suppression control at the time of canceling the park lock will be described. Since the drive torque target value Tm ^* when the parking lock is canceled from the P range to the N range is 0 Nm, only the F / B compensator 42 of the vibration suppression control during normal travel shown in FIG. 4 is calculated. Is expressed by the following equation (7).

Further, the transfer function from the disturbance to the motor rotational speed is expressed by the following equation (8).

When the expressions (7) and (8) are put together, the following expression (9) is obtained.

The normative response (ζ = 1) to the disturbance response is expressed by the following equation (10). However, Gm (s) in Formula (10) is represented by the following Formula (11).

Therefore, H (s) for the equation (9) of the driving force transmission characteristic of the vehicle in the wheel locked state to coincide with the equation (10) of the norm response to the disturbance response is expressed by the following equation (12).

Note that the feedback gain k of the F / B compensator 42 in FIG. 4 takes into account the influence of the control computation time, motor response delay, and sensor signal processing time in order to take into account the delay elements of the control system in the feedback loop. In order to compensate, it is set within the range of 0 to 1 in consideration of the stability of the feedback loop.

FIG. 6 is a flowchart of the vibration suppression control calculation process in the first embodiment. The process starting from step S701 is performed by the electric motor controller 2.

In step S701, a signal related to park lock cancellation is input as input processing. Specifically, the shift position signal, the shift lock park lock release SW signal, and the brake SW signal are detected as hardware signals or acquired by communication from another controller such as a shift controller.

In step S702, it is determined whether or not the brake is on based on the brake SW signal in order to determine whether or not to use the vibration suppression control constant when the parking lock is released. If it is determined that the brake is on, the process proceeds to step S703. If it is determined that the brake is not on, it is determined that normal vibration suppression control is being performed, and the process proceeds to step S708.

In step S703, it is determined whether or not the timer 1 is greater than 0 in order to determine whether or not to use the vibration suppression control constant when the park lock is released. If it is determined that the timer 1 is greater than 0, the process proceeds to step S704. If it is determined that the timer 1 is 0, it is determined that normal vibration suppression control is being performed, and the process proceeds to step S708. Note that the value of the timer 1 is initialized to 0 when the electric motor controller 2 is powered on.

In step S704, it is determined whether or not the second torque target value Tm2 ^* is 0 and the motor rotation speed Nm is smaller than a predetermined value N0. If the second torque target value Tm2 ^* is 0 and the motor rotation speed Nm is smaller than the predetermined value N0, it is possible to suppress the parking lock release shock although the vibration control is being performed when the parking lock is released. Since there is a possibility, it progresses to step S705. In other cases, the process proceeds to step S711 in order to continue the control for suppressing the park lock release shock. As the predetermined value N0, a value adapted in advance is used as a value capable of detecting that the electric motor 4 has been substantially stopped.

In step S704, instead of determining whether the motor speed Nm is smaller than the predetermined value N0, it may be determined whether the vehicle speed is lower than the predetermined vehicle speed.

In step S705, the timer 2 for counting the time during which the second torque target value Tm2 ^* is 0 and the motor rotation speed Nm is kept smaller than the predetermined value N0 is counted up. Note that the value of the timer 2 is initialized to 0 when the electric motor controller 2 is powered on.

In step S706, it is determined whether or not the value of timer 2 is greater than a predetermined value T2. If the value of timer 2 is greater than the predetermined value T2, it is determined that the park lock release shock has been suppressed, and the process proceeds to step S707. On the other hand, if it is determined that the value of timer 2 is equal to or smaller than the predetermined value T2, it is determined that the park lock release shock is still being suppressed, and the process proceeds to step S712.

In step S707, timer 1 and timer 2 are initialized to 0.

In step S708, it is not necessary to suppress the park lock release shock, or it is determined that the park lock release shock has been suppressed after a predetermined period T1 has elapsed since the start of vibration suppression control at the time of park lock release. The timer 2 value indicating that the vibration suppression control is in progress is initialized to zero.

In step S709, it is determined whether or not to shift to park lock cancellation. If it is determined to shift to park lock release, the process proceeds to step S710 to set a vibration suppression control constant at the time of park lock release. If it is determined not to shift to park lock, the process proceeds to step S716.

Here, there are the following methods (M1) to (M4) as a method for determining the transition to park lock cancellation.

(M1) When the shift position of the transmission changes from the P range to another range, that is, when the current shift position is other than the P range and the previous shift position is the P range, it is determined that there is a transition to park lock release. To do.
(M2) When the park lock release SW of the shift knob is turned on, it is determined that there is a transition to the park lock release.
(M3) When the shift position is in the P range and the brake SW signal is OFF → ON, that is, when the current brake SW signal is ON and the previous value is OFF, it is determined that there is a transition to park lock release.
(M4) When the motor rotation speed Nm is equal to or less than the predetermined rotation speed (or the vehicle speed is equal to or less than the predetermined vehicle speed), and the brake SW signal is OFF → ON, that is, the current brake SW signal is ON and the previous value is OFF, Judge that there is a transition to park lock release.

In step S710, in order to start the vibration suppression control at the time of canceling the park lock, the timer 1 indicating the control state and the elapsed time from the start of the control is set to a predetermined value T1. As a result, the damping control at the time of releasing the parking lock can be performed until the timer 1 becomes 0 in the determination in step S703 or the shock determined in steps S704 to S707 is suppressed.

In step S711, the determination in step S704 is denied and it is determined that it is necessary to continue the vibration suppression control when the parking lock is released. Therefore, the timer 2 used in the timer processing (steps S704 to S707) based on the torque condition is set to 0. And

In step S712, a constant Gpl for vibration suppression control at the time of canceling the park lock is set (see equation (5)).

In step S713, it is determined whether the shift range is D or R. If it is determined that the shift range is D or R, the process proceeds to step S714. If it is determined that the shift range is N, the process proceeds to step S715.

In step S714, the drive torque target value Tm ^* is set to zero. This prevents a switching shock that occurs in the vibration suppression control during normal traveling and the vibration suppression control during parking lock release.

In step S715, the timer 1 is counted down to adjust the time for returning to the normal vibration suppression control constant.

In step S716, a constant Gp for damping control during normal running is set. The constant Gp for vibration suppression control during normal traveling can be obtained by the method described in JP2003-9566A and is expressed by the following equation (13). However, b3, b2, b1, b0, a3, a2, a1, and a0 in Formula (13) are each represented by Formula (14).

In the equation (14), Jm is motor inertia, Jw is inertia of the drive wheel, M is vehicle weight, Kd is torsional rigidity of the drive shaft, Kt is a coefficient relating to friction between the tire and the road surface, N is an overall gear ratio, r is the excessive radius of the tire.

In step S717, the final torque target value Tmfin ^* is calculated by performing the damping control shown in the control block diagram of FIG. 4 using the damping control constant set in step S712 or step S716.

As described above, the motor control device for the electric vehicle according to the first embodiment is a control device that sets the motor torque command value based on the vehicle information and controls the torque of the motor connected to the drive wheels. On the other hand, vibration suppression control for suppressing vehicle vibration is performed, and motor torque is controlled according to the motor torque command value for which vibration suppression control has been performed. In this motor control device, when the park lock state in which the wheel is rotationally locked is released, the vibration suppression control using the control constant calculated from the vehicle model in the wheel lock state is performed. Since the vehicle model when the park lock is released is different from the vehicle model in a situation other than when the park lock is released, vibration suppression control using a control constant calculated from a vehicle model that is not in the wheel lock state is performed when the park lock is released. The parklock release shock cannot be completely suppressed. However, in this embodiment, when the parking lock is released, vibration suppression control is performed using a control constant calculated from the vehicle model in the wheel locked state, so that overshoot of the drive shaft torque can be suppressed, and the parking lock release shock can be suppressed. Can be suppressed. Further, since the gear fluctuation does not straddle the backlash section, the tooth contact noise caused by the gear backlash can be suppressed.

Further, the processing means for performing vibration suppression control receives a motor torque command value, and calculates a first torque target value by performing a feedforward calculation for suppressing vibration of the driving force transmission system of the vehicle. Feedback calculation for suppressing vibration of the driving force transmission system of the vehicle based on the deviation of the torque target value calculation means (F / F compensator 41) and the estimated value of the motor rotational speed and the detected value of the motor rotational speed By adding the first torque target value and the second torque target value, second torque target value calculating means (F / B compensator 42) for calculating the second torque target value by performing And adding means (adder 43) for calculating a motor torque command value after damping control. Since this configuration is common for canceling the park lock state and normal driving, there is no need to prepare a separate control system for canceling the park lock. Compared with the case of doing, the amount of calculation can be suppressed.

Further, since the feedback gain k of the F / B compensator 42 is set to a value corresponding to the delay element of the control system in the feedback loop, the control calculation time, motor response delay, sensor signal processing time The effect can be compensated.

Also, when it is detected that the shift position has shifted from the P range to another range other than the P range, it is determined that the park lock state has been released, so the park lock release timing can be reliably detected. Furthermore, when it is detected that the shift position is in the P range and the brake is changed from OFF to ON, it is determined that the park lock state has been released, and therefore the park lock release timing can be reliably detected. Further, since it is determined that the park lock state has been released when it is detected that the motor rotation speed is equal to or less than the predetermined rotation speed or the vehicle speed is equal to or less than the predetermined vehicle speed and the brake is changed from OFF to ON, Can be reliably detected.

When a predetermined time has elapsed after detecting the release of the park lock state, vibration control is performed using a control constant calculated from a vehicle model that is not in the wheel lock state. After that, it is possible to shift to vibration control during normal driving.

In addition, if the vehicle speed exceeds a predetermined threshold while the vibration suppression control is performed using the control constant calculated from the vehicle model in the wheel locked state, the control constant calculated from the vehicle model not in the wheel locked state is used. Perform vibration control. Thereby, even in a vehicle without a park lock signal, it is possible to shift to vibration suppression control during normal traveling.

Furthermore, if the brake changes from on to off while vibration suppression control is performed using the control constant calculated from the vehicle model in the wheel locked state, the control using the control constant calculated from the vehicle model not in the wheel locked state is performed. Perform vibration control. Thereby, even in a vehicle without a park lock signal, it is possible to shift to vibration suppression control during normal traveling.

Further, the motor torque command value for suppressing the vibration generated when the park lock state is released is 0 in a state where the vibration suppression control using the control constant calculated from the vehicle model in the wheel lock state is performed, and When a state in which the motor rotational speed is equal to or lower than the predetermined rotational speed has elapsed for a predetermined time, vibration suppression control using a control constant calculated from a vehicle model that is not in the wheel locked state is performed. As a result, it is possible to shift to the vibration suppression control during normal traveling after reliably suppressing the shock when the parking lock is released.

Further, when it is detected that the shift position has shifted from the P range to the D range or the R range in the state where the vibration suppression control is performed using the control constant calculated from the vehicle model in the wheel locked state, the wheel is not in the locked state. While performing vibration suppression control using the control constant calculated from the vehicle model, the motor torque command value set based on the vehicle information is set to 0 for a predetermined time. As a result, it is possible to prevent a control switching shock when switching from the vibration suppression control when the parking lock is released to the vibration suppression control during normal traveling.

-Second Embodiment-
The motor control device for the electric vehicle in the second embodiment differs from the motor control device for the electric vehicle in the first embodiment in the vibration suppression control calculation processing performed in step S203 of the flowchart of FIG. It is vibration suppression control calculation processing at the time of unlocking.
It is.

FIG. 7 is a control block diagram of a vibration suppression control calculation process at the time of park lock release in the second embodiment. The control in the control block diagram shown in FIG. 7 is motor angular velocity feedback control, and the second torque target value Tm2 ^* is calculated by multiplying the motor rotation speed ωm by the feedback gain Kω and further multiplying the feedback gain k. To do. A method for calculating the feedback gain Kω will be described below.

A transfer function from the disturbance d to the motor rotational speed ωm is expressed by the following equation (15).

When the formulas (5) and (15) are put together, the following formula (16) is obtained.

The normative response (ζ = 1) to the disturbance response is expressed by the following equation (17). However, Gm (s) in Formula (17) is represented by the following Formula (18).

Therefore, the feedback gain Kω is expressed by the following equation (19) from the transfer characteristic equation (16) of the motor angular velocity feedback control and the equation (17) of the norm response to the disturbance response.

However, ω _pl in the equation (19) is expressed by the following equation (20).

Note that the feedback gain k of the feedback compensator in FIG. 7 takes into account the delay elements of the control system in the feedback loop, and therefore can compensate for the effects of control calculation time, motor response delay, and sensor signal processing time. Set as possible.

FIG. 8 is a flowchart of the vibration suppression control calculation process in the second embodiment. Steps in which the same processing as that in the flowchart shown in FIG. 6 is performed are denoted by the same reference numerals and detailed description thereof is omitted. Similar to the flowchart shown in FIG. 6, the process starting from step S <b> 701 is performed by the electric motor controller 2.

If the determination in step S706 is negative, the process in step S710 is terminated, or the process in step S711 is terminated, the process proceeds to step S901. In step S901, the timer 1 is counted down to adjust the time for returning from the vibration suppression control at the time of canceling the park lock to the vibration suppression control at the time of normal traveling.

In step S902, a vibration suppression control process (see FIG. 7) at the time of canceling the park lock is performed.

In step S903, which proceeds when the determination in step S709 is negative, a vibration suppression control process during normal traveling (see FIG. 4) is performed.

As described above, according to the motor control device for an electric vehicle in the second embodiment, the parking lock release shock is suppressed by a simple control system that multiplies the motor rotation speed by the control gain calculated from the vehicle model at the time of park lock release. Can do.

The effect of the vibration suppression control performed by the motor control device of the electric vehicle in the first and second embodiments will be described.

After parking on the uphill road, the parking position is set to the P range, the parking lock is applied, the brake is released, and the drive shaft is twisted and stopped. After that, in order to start again, a phenomenon in the case of releasing the park lock while stepping on the brake will be described with reference to FIG.

FIG. 9 is a diagram illustrating an example of a control result by the motor control device of the electric vehicle according to the first and second embodiments. FIG. 9 shows, in order from the top, the time change of the torque command value (second torque target value Tm2 ^* ), the time change of the motor rotation speed Nm, the time change of the drive shaft twist angle, and the time change of the drive shaft torque. . In FIG. 9, the solid line indicates the control result of the motor control device of the electric vehicle according to the first and second embodiments, and the dotted line indicates the control result of the vibration suppression control device described in JP2003-9566A, which is a conventional example.

At time t0, the P-lock shifts from the P range to the N range, the park lock is released, and the torsion accumulated on the drive shaft is released. At this time, the motor rotation speed decreases in response to the drive shaft torque decreasing to 0 Nm, and the vibration suppression control works to suppress this change, thereby changing the torque command value.

In the conventional vibration suppression control device, even when the parking lock is released, the vehicle model during normal travel is used. Therefore, an error occurs in the vehicle model, and after time t2, the drive shaft torque and the drive shaft twist There is an overshoot at the corner. Therefore, the torsion angle of the drive shaft straddles the backlash section (driveshaft torque ≦ 0 Nm), and tooth contact noise is generated due to gear backlash.

On the other hand, in the control result by the motor control device for the electric vehicle in the first and second embodiments, when the parking lock is released, the vibration suppression control process using the control constant calculated from the vehicle model in the wheel locked state is performed. Thus, overshoot of the drive shaft torque and the twist angle of the drive shaft is suppressed. Thereby, since the torsion angle of the drive shaft does not straddle the backlash section (drive shaft torque> 0 Nm), the tooth contact noise due to the gear backlash can be suppressed.

The present invention is not limited to the embodiment described above.

This application claims priority based on Japanese Patent Application No. 2012-224174 filed with the Japan Patent Office on October 9, 2012, the entire contents of which are incorporated herein by reference.

Claims

In a motor control device for an electric vehicle that sets a motor torque command value based on vehicle information and controls the torque of a motor connected to a drive wheel,
Vibration suppression control means for performing vibration suppression control for suppressing vehicle vibration with respect to the motor torque command value;
Motor torque control means for controlling the motor torque according to the motor torque command value for which the vibration suppression control has been performed;
Park lock release determination means for determining whether or not the park lock state in which the wheel is rotationally locked is released,
With
The vibration suppression control means performs vibration suppression control using a control constant calculated from a vehicle model in a wheel lock state when the park lock state is released.
A motor control device for an electric vehicle.
In the motor control device of the electric vehicle according to claim 1,
The vehicle model Gpl (s) in the wheel lock state has a motor inertia J m , a drive system torsional synthesis K d , an overall gear ratio N, a motor rotation speed ω m , and a motor torque command value T m . Then, the motor control apparatus of the electric vehicle defined by the following formula.
In the motor control device of the electric vehicle according to claim 1 or 2,
The vibration suppression control means receives the motor torque command value and calculates a first torque target value by performing a feedforward calculation for suppressing vibration of the driving force transmission system of the vehicle. The second torque target value is obtained by performing a feedback calculation for suppressing vibration of the driving force transmission system of the vehicle based on the deviation between the value calculating means, the estimated value of the motor speed and the detected value of the motor speed. A second torque target value calculating means for calculating; and an adding means for calculating a motor torque command value after damping control by adding the first torque target value and the second torque target value. ,
A motor control device for an electric vehicle.
In the motor control device of the electric vehicle according to claim 1,
The vibration suppression control means calculates a motor torque command value after vibration suppression control by multiplying the motor rotation speed by a control gain Kω calculated from a vehicle model in a wheel locked state when the park lock state is released. A motor control device for an electric vehicle. However, the control gain K ω is defined by the following equation where J m is the inertia of the motor, K d is the torsional composition of the drive system, and N is the overall gear ratio.
In the motor control device of the electric vehicle according to any one of claims 1 to 4,
The vibration suppression control means includes a feedback compensator that inputs a motor rotation speed and outputs a motor torque command value, and feedback according to a delay element of a control system in a feedback loop including the feedback compensator Gain is set,
A motor control device for an electric vehicle.
In the motor control device of the electric vehicle according to any one of claims 1 to 5,
The park lock cancellation determination means determines that the park lock state has been canceled when it is detected that the shift position has shifted from the P range to another range other than the P range.
A motor control device for an electric vehicle.
In the motor control device of the electric vehicle according to any one of claims 1 to 6,
The parking lock release determination means determines that the parking lock state has been released when detecting that the shift position is in the P range and the brake has changed from OFF to ON,
A motor control device for an electric vehicle.
In the motor control device of the electric vehicle according to any one of claims 1 to 7,
The parking lock release determination means determines that the parking lock state has been released when detecting that the motor rotation speed is equal to or less than the predetermined rotation speed or the vehicle speed is equal to or less than the predetermined vehicle speed and the brake is changed from OFF to ON. To
A motor control device for an electric vehicle.
In the motor control device of the electric vehicle according to any one of claims 1 to 8,
The vibration suppression control means performs vibration suppression control using a control constant calculated from a vehicle model that is not in a wheel lock state when a predetermined time has elapsed after detecting the release of the park lock state.
A motor control device for an electric vehicle.
In the motor control device of the electric vehicle according to any one of claims 1 to 9,
The vibration suppression control means calculates from a vehicle model that is not in a wheel locked state when the vehicle speed exceeds a predetermined threshold in a state where vibration control is performed using a control constant calculated from the vehicle model in the wheel locked state. Perform vibration control using control constants,
A motor control device for an electric vehicle.
In the motor control device of the electric vehicle according to any one of claims 1 to 10,
The vibration suppression control means is calculated from a vehicle model that is not in a wheel lock state when the brake changes from on to off in a state where vibration control is performed using a control constant calculated from the vehicle model in the wheel lock state. Perform vibration control using control constants,
A motor control device for an electric vehicle.
In the motor control device of the electric vehicle according to any one of claims 1 to 11,
The vibration suppression control means is a motor torque command value for suppressing vibration generated when the park lock state is released in a state in which vibration suppression control is performed using a control constant calculated from a vehicle model in the wheel lock state. Is zero, and when a state where the motor rotational speed is equal to or lower than the predetermined rotational speed has elapsed for a predetermined time, vibration suppression control is performed using a control constant calculated from a vehicle model that is not in the wheel locked state
A motor control device for an electric vehicle.
In the motor control device of the electric vehicle according to any one of claims 1 to 12,
The vibration suppression control unit detects that the shift position has shifted from the P range to the D range or the R range in a state where the vibration suppression control is performed using the control constant calculated from the vehicle model in the wheel lock state. In addition to performing vibration suppression control using a control constant calculated from a vehicle model that is not in a wheel locked state, a motor torque command value set based on vehicle information is set to 0 for a predetermined time.
A motor control device for an electric vehicle.
In a motor control method for an electric vehicle that sets a motor torque command value based on vehicle information and controls the torque of a motor connected to a drive wheel,
Judge whether the park lock state with the wheel locked and
When releasing the park lock state, using a control constant calculated from a vehicle model in a wheel lock state, performing vibration suppression control for suppressing vehicle vibration with respect to the motor torque command value,
According to the motor torque command value for which the vibration suppression control is performed, the motor torque is controlled.
A motor control method for an electric vehicle.