JP6233203B2 - Electric vehicle motor control device - Google Patents

Description

  The present invention relates to a motor control device that performs torque control of a motor mounted on an electric vehicle.

  In an electric vehicle equipped with a motor, vibration is generated in the vehicle body when the torque of the motor changes as the accelerator pedal is operated. In order to reduce such vibration, for example, in the control device described in Patent Document 1, when the acceleration of the vehicle is detected within a predetermined time after the deceleration of the vehicle is detected, the increase in the torque of the motor is limited. Torque control is performed. By doing so, it is said that vibration generated in the vehicle body can be reduced when the accelerator pedal is repeatedly depressed and returned.

JP-A-9-308020

  By the way, a power train in which an electric motor and a speed reducer are integrally formed may be mounted on an electric vehicle. However, when the torque of the motor changes due to the operation of an accelerator pedal, the entire power train vibrates, and the vehicle body The transmitted vibration may increase. Powertrain vibration occurs when the motor torque changes from regenerative torque to rebound torque or from recurrent torque to regenerative torque, and the powertrain tilts back and forth beyond the vehicle stop position (reference position). In particular, it becomes larger. However, the torque control of Patent Document 1 is mainly conscious of vibration reduction when the accelerator pedal is repeatedly depressed and returned at a short time interval, and the power train is tilted back and forth with respect to the reference position. It is not intended to reduce vibration.

  The present invention has been made in view of the above circumstances, and it is an object of the present invention to effectively reduce vibration when a power train mounted on an electric vehicle is tilted back and forth with respect to a reference position. .

  The present invention is a motor control device for an electric vehicle including a power train having a motor, wherein the inclination of the power train in the front-rear direction is a reference position that is the position of the power train when the vehicle is stopped When switching to the front side or the rear side, it is determined that the tilt has been switched until it is determined that the tilt has been switched by the tilt determination unit that determines that the tilt has been switched, and the tilt determination unit. And a torque control unit that increases or decreases the torque of the motor at a slower torque increase / decrease rate.

  In the present invention, when the inclination of the power train is switched back and forth with respect to the reference position, the motor is operated at a slower torque increase / decrease rate than after the determination that the inclination has been changed until it is determined that the inclination has changed. Increase or decrease the torque. For this reason, the torque fluctuation at the time when the inclination of the power train is switched can be moderated, and the vibration of the power train can be reduced. Therefore, according to the present invention, vibration when the power train is tilted back and forth with respect to the reference position can be effectively reduced.

It is a schematic diagram of the electric vehicle carrying the motor control apparatus in 1st Embodiment. It is a side view which shows the inclination of a power train. It is a graph which shows the aspect of the torque control at the time of acceleration. It is a graph which shows the aspect of torque control at the time of deceleration. It is a graph which shows an example of the torque change when performing torque control of Drawings 3 and 4. It is a schematic diagram of the electric vehicle carrying the motor control apparatus in 2nd Embodiment. It is a flowchart which shows the torque control in 2nd Embodiment.

[First Embodiment]
DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of a motor control device for an electric vehicle according to the present invention will be described with reference to the drawings. FIG. 1 is a schematic diagram of an electric vehicle 1 equipped with a motor control device 20 according to the first embodiment. The motor control device 20 is a device that performs torque control of the motor 11 based on the accelerator opening and the like. The motor control device 20 will be described in detail later, and the power train 10 mounted on the electric vehicle 1 will be described first.

(Power train)
The power train 10 mainly includes a motor 11 for driving drive wheels (not shown) of the electric vehicle 1, an inverter 12 for changing the torque and the rotational speed of the motor 11, and the inclination of the power train 10 in the front-rear direction. It is a unit in which the angle sensor 13 to be detected is integrally formed. The rotating shaft 11 a of the motor 11 is located at the lower center of the power train 10. Note that the devices and members included in the power train 10 are not limited to those described above. For example, a reduction gear that adjusts the output from the motor 11 may be provided in the power train 10.

  A pair of mounts 14 are provided above the rotating shaft 11a so as to protrude from the left and right sides of the power train 10, and the power train 10 is attached to a vehicle body (not shown) via the mounts 14. The mount 14 is made of an elastic member such as rubber, and reduces vibration transmitted from the power train 10 to the vehicle body.

  When the torque of the motor 11 changes, the power train 10 configured as described above vibrates in the front-rear direction mainly around the rotation shaft 11a of the motor 11. Such vibration is of course reduced to some extent by the mount 14, but it is difficult to overlook when the weight of the power train 10 is large or when the power train 10 is vertically long.

  FIG. 2 is a side view showing the inclination of the power train 10. FIG. 2b shows the position of the power train 10 when the vehicle is stopped (hereinafter referred to as “reference position”), and FIG. 2a shows the state where the power train 10 is inclined rearward from the reference position. The figure shows a state in which the power train 10 is tilted forward from the reference position. In the following description, the inclination of the power train 10 at the reference position is assumed to be 0 degree, the inclination when the power train 10 is inclined backward from the reference position is minus, and the power train 10 is inclined forward from the reference position. The slope of the case is positive.

  When the accelerator pedal is depressed to accelerate the vehicle, the torque of the motor 11 changes from the regenerative torque to the torque torque, and the inclination of the power train 10 is (a) → (b) → (c) in FIG. To change. Conversely, when the accelerator pedal is returned to decelerate the vehicle, the torque of the motor 11 changes from the torque to the regenerative torque, and the inclination of the power train 10 is (c) → (b) → ( It changes as shown in a). Thus, when the torque direction changes, the vibration of the power train 10 becomes particularly large when the inclination of the power train 10 switches from the rear side to the front side or from the front side to the rear side with respect to the reference position. . The motor control device 20 executes torque control for the motor 11 in order to reduce the vibration at this time.

(Motor control device)
Returning to FIG. 1, the description will be continued. The motor control device 20 includes an inclination determination unit 21 and a torque control unit 22. Based on the output from the angle sensor 13, the inclination determination unit 21 determines whether the inclination of the power train 10 is from the rear side (minus) to the front side (plus) or from the front side (plus) to the rear side (plus). It is a functional unit that determines whether or not the switch has been made to (minus). The inclination determination unit 21 also determines whether or not the inclination of the power train 10 has changed from the reference position to the front side (plus) or from the reference position to the rear side (minus) during the start from the stop of the vehicle. Is possible. In the present embodiment, the inclination of the power train 10 can be accurately detected by using the angle sensor 13 that detects the inclination of the power train 10 in the front-rear direction.

  The torque control unit 22 basically determines the target torque of the motor 11 based on the output from the accelerator opening detection unit 30 that detects the opening of the accelerator pedal, and causes the motor 11 to generate the target torque. Therefore, it is a part for sending a control signal to the inverter 12. In addition to this, the torque control unit 22 also has a function of determining the torque increase / decrease rate of the motor 11 based on the determination result by the inclination determination unit 21.

  The functions of the functional units 21 and 22 included in the motor control device 20 are realized by the cooperation of hardware such as a microprocessor and software such as a program. Moreover, each function part 21 and 22 shows the share as a function, and does not necessarily need to be comprised physically independently.

(Torque control)
The torque control unit 22 increases the torque of the motor 11 to accelerate the electric vehicle 1 when the accelerator opening is increased (the accelerator pedal is depressed). FIG. 3A shows the torque increase rate at this time. The inclination determination unit 21 determines that the inclination of the power train 10 is switched when the inclination of the power train 10 changes from minus to plus during acceleration and the inclination subsequently changes to A1. Then, the torque control unit 22 increases the torque of the motor 11 at the torque increase rate Ra for vibration reduction that is slower than the normal torque increase rate Rb until the inclination determination unit 21 determines that the inclination of the power train 10 has been switched. After the above determination, the torque of the motor 11 is increased at the normal torque increase rate Rb. As a result, as shown in FIG. 3b, the torque of the motor 11 gradually increases until the inclination of the power train 10 reaches A1, and increases at a normal rate after the inclination reaches A1. Become.

  Further, the torque control unit 22 reduces the torque of the motor 11 to decelerate the electric vehicle 1 when the accelerator opening is decreased (accelerator pedal is returned). FIG. 4A shows the torque reduction rate at this time. The inclination determination unit 21 determines that the inclination of the power train 10 is switched when the inclination of the power train 10 changes from plus to minus during deceleration and the inclination becomes A2. Then, the torque control unit 22 determines the torque of the motor 11 at a torque reduction rate Rc for vibration reduction that is gentler than the normal torque reduction rate Rd until the inclination determination unit 21 determines that the inclination of the power train 10 has been switched. After the above determination, the torque of the motor 11 is reduced at the normal torque reduction rate Rc. As a result, as shown in FIG. 4b, the torque of the motor 11 gradually decreases until the inclination of the power train 10 reaches A2, and decreases at a normal rate after the inclination reaches A2. Become.

  FIG. 5 is a graph showing an example of torque change when the torque control of FIGS. 3 and 4 is performed. Here, when the accelerator pedal is stepped on at time t1, the accelerator opening increases from time t1 to t4, and the accelerator opening is kept constant from time t4 to t5, and then at time t5. A case will be described in which the accelerator opening is reduced between times t5 and t8 by returning the accelerator pedal. Times t2 and t6 indicate the time when the torque is 0 (the inclination of the power train 10 is 0 degree), time t3 indicates the time when the inclination of the power train 10 is A1, and time t7 indicates the inclination of the power train 10. Indicates the time when becomes A2.

  When the accelerator pedal is depressed at time t1, the torque control unit 22 determines the target torque Ta of the motor 11 based on the output from the accelerator opening detection unit 30, and increases the torque so that the target torque Ta is achieved. . At this time, the torque is increased at the torque increase rate Ra for vibration reduction until the time t3 when the inclination determination unit 21 determines that the inclination of the power train 10 has been switched, and at the normal torque increase rate Rb after the time t3. Increase torque.

  On the other hand, when the accelerator pedal is returned at time t5, the torque control unit 22 determines the target torque Tb of the motor 11 based on the output from the accelerator opening detection unit 30, and the torque is set so that the target torque Tb is achieved. Decrease. At this time, the torque is increased at the torque reduction rate Rc for vibration reduction until time t7 when the inclination determination unit 21 determines that the inclination of the power train 10 has been switched, and after time t7, at the normal torque reduction rate Rd. Reduce torque.

(effect)
During acceleration from time t1 to time t4, the torque direction of the motor 11 changes from regenerative torque (negative torque) to force torque (positive torque), and the inclination of the power train 10 is relative to the reference position. At time t2 when the rear side changes to the front side, the vibration of the power train 10 tends to increase. Similarly, at the time of deceleration from time t5 to t8, the torque direction of the motor 11 changes from the torque to the regenerative torque, and the inclination of the power train 10 changes from the front side to the rear side with respect to the reference position. At time t6, the vibration of the power train 10 tends to increase.

  Therefore, in the present embodiment, during acceleration, the inclination of the power train 10 changes from minus to plus, and the torque increase rate Ra for vibration reduction is applied until time t3 when the power train 10 reaches A1 thereafter. Similarly, during deceleration, the torque reduction rate Rc for reducing vibration is applied until time t7 when the inclination of the power train 10 changes from plus to minus and then reaches A2. For this reason, torque fluctuations at times t2 and t6 when the inclination of the power train 10 is actually switched can be moderated, and vibration of the power train 10 can be reduced. Therefore, vibration when the power train 10 mounted on the electric vehicle 1 is tilted back and forth with respect to the reference position can be effectively reduced. Moreover, since it is determined that the inclination of the power train 10 has been switched, a normal torque increase / decrease rate is applied, so that smooth acceleration / deceleration that does not make the accelerator pedal feel slack can be realized at the same time. Further, when the power train 10 is tilted, noise may be generated due to the power train 10 coming into contact with the vehicle body of the electric vehicle 1. However, by performing torque control as described above, the power train 10 is attached to the vehicle body. The impact at the time of contact can be reduced, and thus the noise can be reduced.

  In the above-described embodiment, the inclination determination unit 21 determines that the inclination of the power train 10 has been switched at a predetermined time when the inclination reaches A1 or A2 after the power train 10 exceeds the reference position. . For this reason, the torque increase / decrease rate for vibration reduction is applied before and after the time when the inclination changes from plus to minus or from minus to plus, and the vibration of the power train 10 can be more reliably reduced. it can.

  In the above embodiment, the inclination determination unit 21 determines whether or not the inclination is switched depending on whether or not the inclination of the power train 10 has reached the predetermined angles A1 and A2 after exceeding the reference position. You may make it determine whether the inclination switched according to whether the elapsed time after exceeding a reference position became predetermined time.

(Modification)
In the embodiment described above, the switching of the tilt is determined based on the output from the angle sensor 13 that detects the tilt of the power train 10. However, it is not essential to provide the angle sensor 13, and instead of the angle sensor 13, for example, based on the output from the position sensor that detects that the inclination of the power train 10 has reached the predetermined angles A <b> 1 and A <b> 2. The switching may be determined. As such a position sensor, any sensor can be used as long as it can detect that the inclination of the power train 10 has reached a predetermined angle. For example, an appropriate sensor such as a contact sensor, an optical sensor, or a vibration sensor is adopted. Can do.

[Second Embodiment]
FIG. 6 is a schematic diagram of an electric vehicle 101 equipped with a motor control device 120 according to the second embodiment. The motor control device 120 according to the present embodiment is different from the motor control device 20 according to the first embodiment in a method for determining a change in the inclination of the power train 10. That is, the inclination determination unit 121 of the motor control device 120 is configured to estimate the switching of the inclination of the power train 10 based on the output from the accelerator opening degree detection unit 30 and the output from the torque control unit 122. Yes. Hereinafter, the details will be described with reference to the flowchart of FIG. Since other points are basically the same as those in the first embodiment, description thereof is omitted here.

  The inclination determination unit 121 first determines whether the torque of the motor 11 is increasing based on the output from the accelerator opening detection unit 30 (step S101). The state where the torque is increasing is the state at the time t1 to t4 when the accelerator pedal is depressed in FIG. If it is determined that the torque is increasing, it is next determined whether or not the current torque is the regenerative torque based on the output from the torque control unit 122 (step S102). When the current torque is regenerative torque (from time t1 to time t2 in FIG. 5), it is estimated that the inclination of the power train 10 is before changing from minus to plus. Therefore, the inclination determination unit 121 does not determine that the inclination of the power train 10 has been switched, and the torque control unit 122 applies the torque increase rate Ra for vibration reduction (step S103).

  On the other hand, if the current torque is not the regenerative torque (in the case of time t2 to t4 in FIG. 5) in step S102, whether or not a predetermined time has elapsed after the torque has changed from the regenerative torque to the force torque. Is determined (step S104). This predetermined time corresponds to the difference between time t3 and time t2 in FIG. When the predetermined time has not elapsed, it is estimated that the inclination of the power train 10 changes from minus to plus, but does not reach the predetermined angle A1. Therefore, the inclination determination unit 121 does not determine that the inclination of the power train 10 has been switched, and the torque control unit 122 applies the torque increase rate Ra for vibration reduction (step S103). When the predetermined time has elapsed, it is estimated that the predetermined angle A1 has been reached after the inclination of the power train 10 has changed from negative to positive. Therefore, the inclination determination unit 121 determines that the inclination of the power train 10 has been switched, and the torque control unit 122 applies the normal torque increase rate Rb (step S105).

  Returning to step S101, if the torque of the motor 11 has not increased, it is next determined whether or not the torque has decreased (step S106). The state where the torque is decreasing is the state from time t5 to time t8 when the accelerator pedal is returned in FIG. If it is determined that the torque is decreasing, it is next determined based on the output from the torque control unit 122 whether or not the current torque is a running torque (step S107). When the current torque is a cruising torque (from time t5 to t6 in FIG. 5), it is estimated that the inclination of the power train 10 is before changing from plus to minus. Therefore, the inclination determination unit 121 does not determine that the inclination of the power train 10 has been switched, and the torque control unit 122 applies the torque reduction rate Rc for vibration reduction (step S108).

  On the other hand, in step S107, if the current torque is not the running torque (from time t6 to t8 in FIG. 5), has the predetermined time elapsed since the torque changed from the running torque to the regenerative torque? It is determined whether or not (step S109). This predetermined time corresponds to the difference between time t7 and time t6 in FIG. When the predetermined time has not elapsed, it is estimated that the inclination of the power train 10 has changed from positive to negative, but has not reached the predetermined angle A2. Therefore, the inclination determination unit 121 does not determine that the inclination of the power train 10 has been switched, and the torque control unit 122 applies the torque reduction rate Rc for vibration reduction (step S108). When the predetermined time has elapsed, it is estimated that the predetermined angle A2 has been reached after the inclination of the power train 10 has changed from positive to negative. Therefore, the inclination determination unit 121 determines that the inclination of the power train 10 has been switched, and the torque control unit 122 applies the normal torque decrease rate Rd (step S110).

  Returning to step S106, the case where the torque is not decreasing is a case where the accelerator opening is maintained in a constant state (a state from time t4 to t5 in FIG. 5). Therefore, in this case, the torque is maintained as it is (step S111).

  As described above, according to the second embodiment, the inclination determination unit 121 appropriately switches the inclination of the power train 10 based on the output from the accelerator opening degree detection unit 30 and the output from the torque control unit 122. Can be determined. Therefore, a sensor for detecting the angle and position of the power train 10 is not required under the control of the motor control device 120, and the number of parts can be reduced.

(Modification)
As a modification of the embodiment in which a sensor for detecting the angle and position of the power train 10 is not provided, the inclination of the power train 10 may be estimated as follows. That is, a power train 10 model is created using the spring constant of the mount 14 holding the power train 10 and the inertia weight of the power train 10, and the power when torque is applied to the motor 11 from this model. The inclination of the train 10 may be obtained. In this case, the inclination determination unit 121 may receive the output from the torque control unit 122 and execute calculation to obtain the inclination of the power train 10 as needed, or the inclination of the power train 10 corresponding to the torque in advance may be calculated. For example, the calculation result may be stored as a map.

[Other Embodiments]
In addition, this invention is not limited to the said embodiment, Unless it deviates from the meaning, it is possible to combine the element of the said embodiment suitably, or to add a various change.

  For example, in the embodiment described above, the inclination of the power train 10 is determined by the inclination determination unit 21 at a predetermined point in time after the power train 10 exceeds the reference position (when the predetermined angle A1 or A2 is reached or when a predetermined time has elapsed). It was determined that it was switched. However, when the power train 10 exceeds the reference position, that is, when the tilt direction of the power train 10 changes, it may be determined that the tilt has been switched.

DESCRIPTION OF SYMBOLS 1,101: Electric vehicle 10: Power train 11: Motor 13: Angle sensor 20, 120: Motor control apparatus 21, 121: Inclination determination part 22, 122: Torque control part

Claims (4)

An electric vehicle motor control device having a power train having a motor,
An inclination for determining that the inclination has been changed when the inclination of the power train in the front-rear direction is switched to the front side or the rear side with respect to a reference position that is the position of the power train in a vehicle stop state. A determination unit;
A torque controller that increases or decreases the torque of the motor at a slower torque increase / decrease rate than after the inclination is determined to be changed until the inclination is determined to be changed by the inclination determination unit;
Equipped with a,
The motor control device for an electric vehicle, wherein the tilt determination unit determines that the tilt has been switched based on an output from an angle sensor that detects the tilt of the power train .   An electric vehicle motor control device having a power train having a motor,
  An inclination for determining that the inclination has been changed when the inclination of the power train in the front-rear direction is switched to the front side or the rear side with respect to a reference position that is the position of the power train in a vehicle stop state. A determination unit;
  A torque controller that increases or decreases the torque of the motor at a slower torque increase / decrease rate than after the inclination is determined to be changed until the inclination is determined to be changed by the inclination determination unit;
  With
  The inclination determination unit determines that the inclination has been switched based on an output from a position sensor that detects that the inclination of the power train has reached a predetermined angle. apparatus.   An electric vehicle motor control device having a power train having a motor,
  An inclination for determining that the inclination has been changed when the inclination of the power train in the front-rear direction is switched to the front side or the rear side with respect to a reference position that is the position of the power train in a vehicle stop state. A determination unit;
  A torque controller that increases or decreases the torque of the motor at a slower torque increase / decrease rate than after the inclination is determined to be changed until the inclination is determined to be changed by the inclination determination unit;
  With
  The inclination determination unit determines whether the inclination is based on the inclination of the power train estimated from the spring constant of the mount holding the power train, the inertia weight of the power train, and the torque of the motor. A motor control device for an electric vehicle, characterized in that it is determined that the switch has been made. The motor control device for an electric vehicle according to any one of claims 1 to 3, wherein the inclination determination unit determines that the inclination is switched at a predetermined time after the power train exceeds the reference position.