JP5862792B2 - Motor control device for electric vehicle and motor control method for electric vehicle - Google Patents

Description

  The present invention relates to an electric vehicle motor control apparatus and an electric vehicle motor control method.

  In the vehicle vibration damping control device described in JP2003-9566A, the torque target value for controlling the 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.

  Here, it is assumed that the parking range (P range) is set on the uphill road and the vehicle stops without applying the foot brake or the 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 vibration suppression control apparatus described in JP2003-9566A, it is necessary to use a feedback gain in consideration of the stability margin of the feedback loop in order to take into account the delay element of the control system in the feedback loop. Since the feedback gain during normal driving is calculated from the vehicle model in which the wheels are unlocked, that is, in the normal driving state, the feedback gain is different from when the parking lock is released.

  In addition, the feedback compensator for vibration suppression control has a characteristic that the gain of a relatively high frequency of 50 Hz or higher is increased to near 0 dB or higher, and a high-frequency torque component is output by noise due to rotation angle or speed detection. May end up. Here, when the vibration component in the 25 to 150 Hz band is transmitted from the motor unit or the drive shaft or the like to the body chassis via the mount or the like, a muffled sound may be generated. For this reason, when the feedback gain is increased, the high frequency gain is also increased, and a muffled sound appears remarkably.

  When the same feedback gain as the feedback gain used in vibration suppression control during normal travel is used when the park lock is released, torque overshoot occurs and convergence is delayed, resulting in a park lock release shock. As a result, since the gear variation straddles the backlash section, a tooth contact sound is generated, which may cause anxiety and discomfort to the driver.

  An object of the present invention is to suppress vibrations that occur when parking lock is canceled.

  In the motor control device for an electric vehicle according to an embodiment, when performing the vibration suppression control for suppressing the vehicle vibration with respect to the motor torque command value, when the park lock state is canceled, when the park lock state is not canceled As compared with the above, the feedback gain used in the feedback control of the vibration suppression control is increased.

  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 illustrating 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 an example of a map showing the relationship between the road surface gradient θk and the F / B gain when park lock is released. FIG. 8 is a control block diagram of the vibration suppression control calculation processing at the time of canceling the park lock according to the second embodiment. FIG. 9 is a flowchart of the vibration suppression control calculation process in the second embodiment. FIG. 10 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, and turns on / off the switching elements in accordance with a drive signal, thereby removing from the battery 1. 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 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.

  The gradient sensor 10 detects the gradient of the road surface.

  FIG. 2 is a flowchart showing a flow of processing 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 a vehicle speed sensor (not shown) or another controller such as 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.

  The 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).

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

  The DC voltage value Vdc (V) is obtained from a power supply voltage value transmitted from a voltage sensor (not shown) provided on a DC power supply line between the battery 1 and the inverter 3 or 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, 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 of the transmission input in step S201, the drive torque target value Tm. Set ^* . 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, based on the drive torque target value Tm ^* set in step S202 and the motor rotational speed ωm, the vibration of the drive force transmission system (the drive shaft vibration) can be achieved without sacrificing the response of the drive shaft torque. A final torque target value Tmfin ^* that suppresses torsional vibration or 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. Further, the feedback gain (F / B gain) of the vibration suppression control when the parking lock is released is set to a value larger than the feedback gain of the vibration suppression control when the parking lock is not released. Details of the vibration suppression control calculation processing performed in step S203 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 current 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 obtained in this way.

  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 vibration suppression control during normal travel other than when the park lock is released is the same as the vibration suppression control method described in JP2003-9566A.

  FIG. 4 is a control block diagram of the vibration suppression control calculation process. 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 process 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, and details thereof are disclosed in JP2003-9566. A. 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, 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 in which the driving force transmission system of the vehicle in the wheel lock state is modeled. The equation of motion of the vehicle is expressed by the following equations (1) to (3).

Here, each parameter in Formula (1)-(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).

  The F / B gain k of the F / B compensator 42 shown in FIG. 4 can be set between 0 and 1. By setting k = 1, the F / B compensator 42 is in an ideal state (ζ = 1). ) The F / B gain k is set so as to compensate for the influence of the control calculation time, the motor response delay, and the sensor signal processing time in consideration of the delay element of the control system in the feedback loop. When the park lock is released, the stability of the closed loop of the F / B compensator 42 is evaluated based on the vehicle model Gpl (s) when the parking lock is released, and is larger than the F / B gain used for vibration control during normal driving. The value is set as the F / B gain k.

  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. Further, the road surface gradient θk detected by the gradient sensor 10 is also input. The slope θk of the road surface is detected as a positive value for the slope of the uphill road and a negative value for the slope of the downhill road. The road surface gradient may be estimated based on the longitudinal acceleration and vehicle speed detected by a longitudinal G sensor (not shown).

  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 F / B gain of vibration suppression control 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 increase the F / B gain of the vibration suppression control 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 rotational 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 parking lock release shock is being suppressed, and the process proceeds to step S711 in order to continuously increase the F / B gain k. 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 rotation 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 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 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 zero.

  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 the park lock release, the process proceeds to step S710 to set the F / B gain k of the vibration suppression control when the park lock is released. If it is determined that the park lock release is not shifted, the vibration suppression control during normal driving is determined. In step S714, the F / B gain k is set.

Here, as a method for determining whether to release the park lock, there are the following methods (M1) to (M4).
(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 when the park lock is released, the timer 1 indicating the state during the vibration suppression control 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 canceling the park 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 process (steps S704 to S707) based on the torque condition is set to 0. And

  In step S712, an F / B gain k for vibration suppression control at the time of canceling the park lock, which is necessary for vibration suppression control processing in step S715 described later, is set. As the F / B gain k of the vibration suppression control when the park lock is released, a value calculated using the vehicle model Gpl (s) when the park lock is released is used. The F / B gain k during normal driving is calculated using a vehicle model Gp (s) that considers the wheels. However, during normal driving, it is necessary to set the stability under the worst condition of the wheel characteristics. It is necessary to set a feedback gain with a large stability margin. However, when the parking lock is canceled, the wheels are always in a stopped state, so it is not necessary to consider a wheel whose characteristics are likely to change, and a feedback gain larger than that during normal driving can be set.

  Specifically, as shown in FIG. 7, a map in which an optimum F / B gain is set by an experiment or the like in advance according to the road surface gradient θk is prepared, and based on the road surface gradient θk input in step S701. The F / B gain k is set by referring to the map shown in FIG. In the map shown in FIG. 7, when the road surface gradient θk is in the range of θk1 <θk <θk2 (θk1 <0, θk2> 0), the F is larger than the F / B gain of the vibration suppression control during normal traveling. / B gain k1. Further, in the range where the road surface gradient θk is equal to or larger than θk2, the F / B gain k is set to a value equal to or larger than k1, and the F / B gain k is increased as the road surface gradient θk is increased (the degree of climbing is increased). . In the range where the road surface gradient θk is equal to or less than θk1, the F / B gain k is set to a value equal to or greater than k1, and the F / B gain k is increased as the road surface gradient θk decreases (the degree of downhill increases). Yes. This makes it possible to increase the F / B gain k for vibration suppression control at the time of parking lock cancellation on a steep slope (uphill, downhill) road surface, effectively suppressing the parking lock cancellation shock. can do.

  In step S713, the timer 1 is counted down in order to adjust the time for returning from the F / B gain k of the vibration suppression control when the parking lock is released to the F / B gain k of the vibration suppression control during normal traveling.

  In step S714, the F / B gain k for vibration suppression control during normal travel is set.

In step S715, the final torque target value Tmfin ^* is calculated by performing damping control shown in the control block diagram of FIG. 4 using the F / B gain k set in step S712 or step S714. More specifically, in vibration suppression control during normal travel other than when parking lock is released, the vehicle model is Gp (s), and vibration suppression control using F / B gain k during normal travel is performed. In the vibration damping control when the park lock is released, the vibration damping control is performed using the vehicle model Gpl (s) in the wheel locked state and the F / B gain k larger than the F / B gain k during normal driving.

  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, vibration suppression control is performed by performing at least feedback control, and the feedback gain k used in the feedback control is increased when the park lock state is released, compared to the case other than when the park lock state is released. When the park lock is released, the fluctuation of the motor is negligible, so there is no need to consider the noise. Therefore, a feedback gain larger than the feedback gain used in vibration suppression control during normal traveling can be used. Thereby, the overshoot of the drive shaft torque can be suppressed, and the parking lock release shock 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, when the park lock state is canceled, the feedback gain k is changed according to the slope of the road surface. When vibration control is performed using the same feedback gain k as when the road gradient is small when the road gradient is large, the drive shaft torque overshoot increases and the tooth contact noise due to backlash tends to increase. is there. Therefore, by increasing the feedback gain as the road surface gradient increases, it is possible to suppress the overshoot of the drive shaft torque and suppress the parking lock release shock and the gear tooth contact noise.

  In addition, 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 that 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.

  In addition, when a predetermined time has elapsed after detecting the release of the park lock state, vibration suppression control using a feedback gain smaller than the feedback gain used when the park lock state is released is performed. Thereby, even in a vehicle without a park lock signal, it is possible to change the feedback gain when the park lock state is released to the feedback gain during normal driving.

  In addition, when the vehicle speed exceeds a predetermined threshold while the vibration suppression control using the feedback gain when the park lock state is released, the vibration suppression using the feedback gain smaller than the feedback gain when the park lock state is released is performed. Take control. Thereby, even in a vehicle without a park lock signal, it is possible to change the feedback gain when the park lock state is released to the feedback gain during normal driving.

  Furthermore, if the brake changes from ON to OFF while performing vibration suppression control using the feedback gain when the park lock state is released, vibration suppression using a feedback gain smaller than the feedback gain when the park lock state is released is performed. Take control. Thereby, even in a vehicle without a park lock signal, it is possible to change the feedback gain when the park lock state is released to the feedback gain during normal driving.

  The motor torque command value for suppressing the vibration generated when the park lock state is released is 0 when the vibration suppression control using the feedback gain at the release of the park lock state is performed, and the motor When a state in which the rotational speed is equal to or lower than the predetermined rotational speed has elapsed for a predetermined time, vibration suppression control using a feedback gain smaller than the feedback gain at the time of canceling the park lock state is performed. As a result, it is possible to change to the feedback gain of the vibration suppression control during normal traveling after reliably suppressing the shock when the parking lock is released.

-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.

FIG. 8 is a control block diagram of the vibration suppression control calculation processing at the time of canceling the park lock according to the second embodiment. The control in the control block diagram shown in FIG. 8 is motor angular velocity feedback control, and the second torque target value Tm2 ^* is calculated by multiplying the motor rotational 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 (7).

When formulas (5) and (7) are put together, the following formula (8) is obtained.

The normative response (ζ = 1) to the disturbance response is expressed by the following equation (9). However, Gm (s) in Formula (9) is represented by the following Formula (10).

Therefore, the feedback gain Kω is expressed by the following equation (11) from the transfer characteristic equation (8) of the motor angular velocity feedback control and the norm response equation (9) for the disturbance response.

However, ω _pl in the equation (11) is expressed by the following equation (12).

  The F / B gain k shown in FIG. 8 takes into account the delay element of the control system in the feedback loop, so that the influence of the control calculation time, motor response delay, and sensor signal processing time can be compensated. Set. As in the first embodiment, when the parking lock is released, the stability of the closed loop of the F / B compensator is evaluated by the vehicle model Gpl (s) when the parking lock is released, and the vibration suppression control during normal driving is evaluated. A value larger than the F / B gain is set. The method for setting the F / B gain k is the same as in the first embodiment.

  FIG. 9 is a flowchart of the vibration suppression control calculation process in the second embodiment. Steps for performing the same processing as the processing in the flowchart shown in FIG. Similar to the flowchart shown in FIG. 6, the process starting from step S <b> 701 is performed by the electric motor controller 2.

  In step S910 following step S713, the damping control at the time of canceling the park lock, that is, the damping control shown in the control block diagram of FIG. 8 is performed using the F / B gain k set in step S712.

  On the other hand, in step S902, which proceeds after the determination in step S709 is denied, vibration control during normal traveling, that is, vibration control shown in the control block diagram of FIG. 4 is performed.

  As described above, according to the motor control device for an electric vehicle in the second embodiment, when the park lock state is released, feedback using the feedback gain k calculated from the vehicle model Gpl (s) in the wheel lock state and the motor rotation speed is used. Since the control is performed, the park lock release shock can be suppressed with a simple control system.

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

  It is assumed that 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. 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. 10 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. 10 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. 10, the solid line shows the control result of the motor control device of the electric vehicle in the first and second embodiments, and the dotted line shows the control result of the vibration suppression control device described in Japanese Patent Laid-Open No. 2003-9566 which is a conventional example. Show.

  At time t0, the P range is changed to the N range, the park lock is released, and the torsion accumulated in 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 vibration damping control device of the conventional example, even when the parking lock is released, the vibration damping control using the same F / B gain as during normal driving is performed. Overshoot occurs at the twist angle. Therefore, the torsion angle of the drive shaft straddles the backlash section (driveshaft torque ≦ 0 Nm), and tooth contact noise due to gear backlash is generated.

  On the other hand, in the control result by the motor control device of the electric vehicle in the first and second embodiments, when the parking lock is released, vibration suppression using an F / B gain larger than the F / B gain during normal driving is used. Since control is performed, 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 above-described embodiments, and various modifications and applications can be made without departing from the gist of the present invention.

  This application claims the priority based on Japanese Patent Application No. 2012-224178 for which it applied to Japan Patent Office on October 9, 2012, and all the content of this application is integrated in this specification by reference.

Claims (10)

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 the vibration suppression control by performing at least feedback control, and the feedback control is more performed when the park lock state is released than when the park lock state is not released. In addition to increasing the feedback gain used in, the feedback control using the feedback gain calculated from the vehicle model in the wheel lock state and the motor rotation speed is performed.
A motor control device for an electric vehicle. In the motor control device of the electric vehicle according to claim 1 ,
Further comprising a slope detection means for detecting the slope of the road surface;
The vibration suppression control means changes the feedback gain according to a road gradient 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 or 2 ,
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 3 ,
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 4 ,
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 5 ,
The vibration suppression control means performs a vibration suppression control using a feedback gain smaller than a feedback gain used when releasing the park 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 6 ,
The vibration suppression control means is smaller than the feedback gain at the cancellation of the park lock state when the vehicle speed exceeds a predetermined threshold in the state of performing the vibration suppression control using the feedback gain at the cancellation of the park lock state Perform damping control using feedback gain,
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 vibration suppression control means is smaller than the feedback gain at the time of releasing the park lock state when the brake changes from on to off in the state of performing the vibration suppression control using the feedback gain at the time of release of the park lock state. Perform damping control using feedback gain,
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 a vibration suppression control using a feedback gain when the park lock state is released, and a motor torque command value for suppressing vibration generated when the park lock state is released is 0. And when a state where the motor rotation speed is equal to or less than the predetermined rotation speed has elapsed for a predetermined time, vibration suppression control using a feedback gain smaller than the feedback gain at the time of releasing the park lock state is performed.
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
By performing at least feedback control, damping control for suppressing vehicle vibration is performed on 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,
In the vibration suppression control, when the park lock state is released, the feedback gain used in the feedback control is increased compared to the case other than when the park lock state is released, and the feedback calculated from the vehicle model in the wheel locked state Perform feedback control using gain and motor speed,
The motor control method of the electric vehicle characterized by the above-mentioned.

Images