JP6237789B2 - Electric vehicle control device and electric vehicle control method - Google Patents

Description

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

  2. Description of the Related Art Conventionally, a regenerative brake control device for an electric vehicle that includes a setting unit that can arbitrarily set a regenerative braking force of an electric motor and performs regeneration of the electric motor with a regenerative braking force set by the setting unit is known (see JP8-79907A). ).

  However, when the regenerative braking force set by the setting means is large, there is a problem that vibration occurs in the front-rear direction of the vehicle body when the electric vehicle decelerates to zero with the set regenerative braking force. Occurs.

  An object of the present invention is to provide a technique for suppressing the occurrence of vibration in the front-rear direction of a vehicle body when an electric vehicle is stopped by a regenerative braking force.

An electric vehicle control device according to one aspect of the present invention is a control device for an electric vehicle that uses a motor as a travel drive source and decelerates due to the regenerative braking force of the motor, and detects disturbance amount of an accelerator , and disturbance torque that acts on the motor Is estimated, a motor torque command value is calculated, and the motor is controlled based on the calculated motor torque command value. The disturbance torque is estimated based on the model Gp (s) of the transfer characteristic between the torque input to the vehicle and the rotational speed of the motor. When the accelerator operation amount is equal to or smaller than the predetermined value and the electric vehicle is about to stop, the motor torque command value is converged to the disturbance torque as the rotational speed of the motor decreases.

  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 an electric vehicle control device according to an embodiment. FIG. 2 is a flowchart showing a flow of processing of motor current control performed by the motor controller. FIG. 3 is a diagram illustrating an example of an accelerator opening-torque table. FIG. 4 is a diagram modeling a vehicle driving force transmission system. FIG. 5 is a block diagram for realizing the stop control process. FIG. 6 is a diagram for explaining a method of calculating the motor rotation speed F / B torque Tω based on the motor rotation speed ωm. FIG. 7 is a block diagram for explaining a method of calculating the disturbance torque estimated value Td based on the motor rotational speed ωm and the motor torque command value Tm ^* . FIG. 8 is a diagram illustrating an example of a control result by the control device for the electric vehicle according to the embodiment. FIG. 9 is a diagram illustrating an example of a control result by the control device for an electric vehicle according to the embodiment, and is a time chart when the accelerator operation amount is set to zero. FIG. 10 is a diagram illustrating an example of a control result by the control device for an electric vehicle according to the embodiment, and is a time chart when the accelerator operation amount is constant. FIG. 11 is a diagram illustrating an example of a control result by the control apparatus for an electric vehicle according to the embodiment, and is a time chart when the accelerator operation amount is gradually increased. FIG. 12 is a block diagram for realizing the stop control process when the motor rotational speed F / B torque Tω is set as the second torque target value Tm2 ^* .

  FIG. 1 is a block diagram illustrating a main configuration of an electric vehicle including an electric vehicle control device according to an embodiment. The control device for an electric vehicle according to the present invention is applicable to an electric vehicle that includes an electric motor as a part or all of a drive source of the vehicle and can travel by the driving force of the electric motor. Electric vehicles include not only electric vehicles but also hybrid vehicles and fuel cell vehicles. In particular, the control device for an electric vehicle in the present embodiment can be applied to a vehicle that can control acceleration / deceleration and stop of the vehicle only by operating an accelerator pedal. In this vehicle, the driver depresses the accelerator pedal at the time of acceleration and reduces the amount of depression of the accelerator pedal at the time of deceleration or stop, or sets the depression amount of the accelerator pedal to zero. Note that the deceleration of the vehicle means that the vehicle speed approaches zero.

  The motor controller 2 inputs signals indicating the vehicle state such as the vehicle speed V, the accelerator opening AP, the rotor phase α of the electric motor (three-phase AC motor) 4, the currents iu, iv, iw of the electric motor 4 as digital signals. Then, a PWM signal for controlling the electric motor 4 is generated based on the input signal. The motor controller 2 generates a drive signal for the inverter 3 in accordance with 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. The electric motor 4 collects the kinetic energy of the vehicle as electric energy by generating a regenerative driving force when the electric motor 4 rotates with the drive wheels 9a and 9b and rotates when the vehicle is traveling. 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 α of the electric motor 4.

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

  In step S201, a signal indicating the vehicle state is input. Here, the vehicle speed V (km / h), the accelerator opening AP (%), the rotor phase α (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, and a DC voltage value Vdc (V) between the battery 1 and the inverter 3 are input.

  The vehicle speed V (km / h) is acquired by communication from a vehicle speed sensor (not shown) or another controller. 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 AP (%) 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 rotor phase α (rad) of the electric motor 4 is acquired from the rotation sensor 6. The rotational speed Nm (rpm) of the electric motor 4 is obtained by dividing the rotor angular speed ω (electrical angle) by the pole pair number p of the electric motor 4 to obtain a motor rotational speed ωm (rad / s) is obtained by multiplying the obtained motor rotational speed ωm by 60 / (2π). The rotor angular velocity ω is obtained by differentiating the rotor phase α.

  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 first torque target value Tm1 ^* is set. Specifically, the first torque target value Tm1 ^* is set by referring to the accelerator opening-torque table shown in FIG. 3 based on the accelerator opening AP and the motor rotational speed ωm input in step S201. To do. As described above, the control device for an electric vehicle according to the present embodiment is applicable to a vehicle that can control acceleration / deceleration or stop of the vehicle only by operating the accelerator pedal, and at least the accelerator pedal is fully closed. In order to make it possible to stop, in the accelerator opening-torque table shown in FIG. 3, the motor torque is set so that the motor regeneration amount becomes large when the accelerator opening is 0 (fully closed). . That is, the negative motor torque is set so that the regenerative braking force works when the motor speed is positive and at least when the accelerator opening is 0 (fully closed). However, the accelerator opening-torque table is not limited to that shown in FIG.

In step S203, stop control processing is performed. Specifically, the stop time of the electric vehicle is determined. Before the stop, the first torque target value Tm1 ^* calculated in step S202 is set to the motor torque command value Tm ^*. The second torque target value Tm2 ^* that converges to the disturbance torque estimated value Td as the speed decreases is set as the motor torque command value Tm ^* . The second torque target value Tm2 ^* is positive torque on an uphill road, negative torque on a downhill road, and almost zero on a flat road. Thereby, the stop state can be maintained regardless of the gradient of the road surface, as will be described later. Details of the stop control process 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 motor torque target value Tm ^* , the motor rotation speed ωm, and the DC voltage value Vdc calculated in step S203. For example, by preparing in advance a table that defines the relationship between the torque command value, the motor rotation speed, the DC voltage value, the d-axis current target value, and the q-axis current target value, and referring to this table, The d-axis current target value id ^* and the q-axis current target value iq ^* are obtained.

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 α of the electric motor 4. Subsequently, d-axis and q-axis voltage command values vd and vq are calculated from a deviation between the d-axis and q-axis current command values id ^* and iq ^* and the d-axis and q-axis current id and iq. In addition, you may make it add the non-interference voltage required in order to cancel the interference voltage between dq orthogonal coordinate axes with respect to the calculated d-axis and q-axis voltage command values vd and vq.

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 rotor phase α of the electric motor 4. 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 torque command value Tm ^* by opening and closing the switching element of the inverter 3 by the PWM signals tu, tv, and tw thus obtained.

  Here, before describing the stop control process performed in step S203, the transfer characteristic Gp (s) from the motor torque Tm to the motor rotation speed ωm in the control apparatus for the electric vehicle in the present embodiment will be described.

FIG. 4 is a diagram in which a driving force transmission system of a vehicle is modeled, and each parameter in the figure is as shown below.
J _m : Inertia of electric motor J _w : Inertia of drive wheel M: Vehicle weight K _d : Torsional rigidity of drive system K _t : Coefficient related to friction between tire and road surface N: Overall gear ratio r: Tire load radius ω _m : the electric motor angular velocity T _m: torque target value T _d: a torque of the drive wheel F: force applied to the vehicle V: vehicle speed omega _w: angular velocity of the drive wheel

Then, the following equation of motion can be derived from FIG. However, the asterisk ( ^* ) attached to the upper right of the code | symbol in Formula (1)-(3) represents the time differentiation.

When the transfer characteristic Gp (s) from the torque target value Tm of the electric motor 4 to the motor rotational speed ωm is obtained based on the equation of motion represented by the expressions (1) to (5), it is expressed by the following expression (6). .

However, each parameter in Formula (6) is represented by following Formula (7).

When the poles and zeros of the transfer function shown in equation (6) are examined, it can be approximated to the transfer function of the following equation (8), and one pole and one zero show extremely close values. This corresponds to that α and β in the following formula (8) show extremely close values.

Therefore, by performing pole-zero cancellation (approximate α = β) in equation (8), Gp (s) is transmitted as (second order) / (third order) as shown in the following equation (9). Configure characteristics.

  Next, details of the stop control process performed in step S203 of FIG. 2 will be described. FIG. 5 is a block diagram for realizing the stop control process.

  The motor rotation speed F / B torque setter 501 is based on the detected motor rotation speed ωm, and the motor rotation speed feedback torque Tω (hereinafter referred to as the motor rotation speed) for stopping the electric vehicle by the regenerative braking force of the electric motor 4. F / B torque Tω) is calculated.

  FIG. 6 is a diagram for explaining a method of calculating the motor rotation speed F / B torque Tω based on the motor rotation speed ωm. The motor rotation speed F / B torque setter 501 includes a multiplier 601 and calculates a motor rotation speed F / B torque Tω by multiplying the motor rotation speed ωm by a gain Kvref. However, Kvref is a negative (minus) value required to stop the electric vehicle just before the electric vehicle stops, and is appropriately set based on, for example, experimental data. That is, the motor rotation speed F / B torque Tω is set as a torque that provides a larger regenerative braking force as the motor rotation speed ωm increases.

  The motor rotation speed F / B torque setter 501 has been described as calculating the motor rotation speed F / B torque Tω by multiplying the motor rotation speed ωm by the gain Kvref. The motor rotation speed F / B torque Tω may be calculated using a regenerative torque table that defines torque, an attenuation rate table that stores in advance the attenuation rate of the motor rotation speed ωm, or the like.

The disturbance torque estimator 502 calculates a disturbance torque estimated value Td based on the detected motor rotation speed ωm and the motor torque command value Tm ^* .

FIG. 7 is a block diagram for explaining a method of calculating the disturbance torque estimated value Td based on the motor rotational speed ωm and the motor torque command value Tm ^* .

  The control block 701 functions as a filter having a transfer characteristic of H (s) / Gp (s), and performs the filtering process by inputting the motor rotation speed ωm, whereby the first motor torque estimated value is obtained. Is calculated. Gp (s) is a model of transmission characteristics of torque input to the vehicle and the rotational speed of the motor, and H (s) is the difference between the denominator order and the numerator order, and the denominator order and numerator of the model Gp (s). It is a low-pass filter having a transfer characteristic that is greater than or equal to the difference from the order.

The control block 702 functions as a low-pass filter having a transfer characteristic of H (s), and calculates a second motor torque estimated value by performing a filtering process by inputting the motor torque command value Tm ^*. To do.

  The subtractor 703 calculates a disturbance torque estimated value by subtracting the first motor torque estimated value from the second motor torque estimated value.

  In the present embodiment, the disturbance torque estimated value Td is calculated by filtering the deviation between the second motor torque estimated value and the first motor torque estimated value by the control block 704. The control block 704 functions as a filter having a transfer characteristic of Hz (s), and performs a filtering process by inputting a deviation between the second motor torque estimated value and the first motor torque estimated value. Thus, the disturbance torque estimated value Td is calculated.

Here, the transfer characteristic Hz (s) will be described. When equation (9) is rewritten, the following equation (10) is obtained. However, ξ _z , ω _z , ξ _p , and ω _p in the equation (10) are each expressed by the equation (11).

From the above, Hz (s) is expressed by the following equation (12). However, ξ _c > ξ _z . Also, ξ _c > 1 is set in order to enhance the vibration suppression effect in a deceleration scene with gear backlash.

  In this embodiment, the disturbance torque is estimated by a disturbance observer as shown in FIG. 7, but may be estimated using a measuring instrument such as a vehicle front-rear G sensor.

Here, disturbances include air resistance, modeling errors due to vehicle mass fluctuations due to the number of passengers and loading capacity, tire rolling resistance, road surface gradient resistance, etc., but disturbances that are dominant immediately before stopping The factor is gradient resistance. Although the disturbance factor varies depending on the driving conditions, the disturbance torque estimator 502 calculates the disturbance torque estimated value Td based on the motor torque command value Tm ^* , the motor rotation speed ωm, and the vehicle model Gp (s). Disturbance factors can be estimated collectively. This makes it possible to realize a smooth stop from deceleration under any driving condition.

Returning to FIG. The adder 503 adds the motor rotational speed F / B torque Tω calculated by the motor rotational speed F / B torque setter 501 and the disturbance torque estimated value Td calculated by the disturbance torque estimator 502, A second torque target value Tm2 ^* is calculated.

The torque comparator 504 compares the magnitudes of the first torque target value Tm1 ^* and the second torque target value Tm2 ^* , and sets the torque target value having the larger value as the motor torque command value Tm ^* . While the vehicle is running, the second torque target value Tm2 ^* is smaller than the first torque target value Tm1 ^* , and when the vehicle decelerates and comes to a stop (the vehicle speed is equal to or less than a predetermined vehicle speed), the first torque target value Tm1 ^* Be bigger than. Therefore, if the first torque target value Tm1 ^* is larger than the second torque target value Tm2 ^* , the torque comparator 504 determines that the vehicle is just before stopping and determines the motor torque command value Tm ^* as the first torque target value. Set to Tm1 ^* . Further, when the second torque target value Tm2 ^* becomes larger than the first torque target value Tm1 ^* , the torque comparator 504 determines that the vehicle is about to stop and sets the motor torque command value Tm ^* as the first torque target value. The value Tm1 ^* is switched to the second torque target value Tm2 ^* . In order to maintain the stop state, the second torque target value Tm2 ^* converges to a positive torque on an uphill road, a negative torque on a downhill road, and approximately zero on a flat road.

  FIG. 8 is a diagram illustrating an example of a control result by the control device for the electric vehicle according to the embodiment. FIGS. 8A to 8C show control results when the vehicle stops on an uphill road, a flat road, and a downhill road. In each figure, the motor rotation speed, the motor torque command value, and the vehicle longitudinal acceleration are sequentially shown from the top. Represents.

At time t0, the electric motor 4 is decelerated based on the first torque target value Tm1 ^* calculated in step S202 of FIG.

At time t1, the second torque target value Tm2 ^* is greater than the first torque target value Tm1 ^* in step S504 in FIG. 5, and it is determined that the vehicle is about to stop, so that the motor torque command value Tm ^* is the first value. It switched from the torque target value Tm1 ^* of the second torque target value Tm2 ^*. Thereafter, as the motor rotation speed ωm decreases, the motor torque command value Tm ^* gradually approaches the estimated disturbance torque value Td.

At time t3, as shown in FIGS. 8A to 8C, the motor torque command value Tm ^* converges to the disturbance torque estimated value Td regardless of the uphill road, the flat road, and the downhill road. Thereby, the smooth stop without the acceleration vibration of the front-back direction at the time of a stop is realizable. After time t3, it can be seen that the motor rotation speed ωm is 0 regardless of the uphill road, the flat road, and the downhill road, and the stopped state is maintained.

  Next, with reference to FIGS. 9 to 11, a description will be given of a control result by the control device for an electric vehicle in a more specific embodiment in consideration of the accelerator operation amount.

  FIGS. 9-11 is a figure which shows an example of the control result by the control apparatus of the electric vehicle in one Embodiment similarly to FIG. 9 shows the control result when the accelerator operation amount is zero, FIG. 10 shows the control result when the accelerator operation amount is constant, and FIG. 11 shows the control result when the accelerator operation amount is gradually increased. Show. 9 (a) to (c), FIGS. 10 (a) to (c), and FIGS. 11 (a) to (c) represent control results when stopping on an uphill road, a flat road, and a downhill road, respectively. Yes. In each figure, the motor rotation speed, motor torque command value, vehicle longitudinal acceleration, and accelerator opening are shown in order from the top.

  In addition to the motor torque command value (solid line) and the disturbance torque estimated value (one-dot chain line), the diagrams showing the motor torque command values in FIGS. 9 to 11 include the first torque target value (dotted line), 2 shows a torque target value (broken line).

At time t0, the electric motor is decelerated based on the first torque target value Tm1 ^* calculated in step S202 of FIG.

At time t1, the second torque target value Tm2 ^* is greater than the first torque target value Tm1 ^* in step S504 in FIG. 5, and it is determined that the vehicle is about to stop, so that the motor torque command value Tm ^* is the first value. It switched from the torque target value Tm1 ^* of the second torque target value Tm2 ^*. Thereafter, as the motor rotation speed ωm decreases, the motor torque command value Tm ^* gradually approaches the estimated disturbance torque value Td. During this time, as shown in FIGS. 9 to 11, the motor torque command value Tm ^* does not depend on the accelerator operation amount and converges to the disturbance torque estimated value Td.

At time t3, as shown in (a) to (c) of FIGS. 9 to 11, the motor torque command value Tm regardless of the accelerator opening and the road surface condition (uphill road, flat road, downhill road). ^* Converges to the estimated disturbance torque Td. Thereby, the smooth stop without the acceleration vibration of the front-back direction at the time of a stop is realizable. After the time t3, the motor rotation speed ωm is 0 regardless of the accelerator opening and the road surface condition, and it can be seen that the stopped state is maintained.

As described above, when it is determined that the vehicle is about to stop in S504, the motor torque command value Tm ^* is switched from the first torque target value Tm1 ^* to the second torque target value Tm2 ^* regardless of the accelerator operation amount. As the rotational speed decreases, it converges to the estimated disturbance torque.

Here, on the uphill road, a section straddling the gear backlash (immediately before time t2 in FIGS. 8A to 11A) occurs. When a disturbance caused by a modeling error with Gp (s) generated in a scene or the like straddling a gear backlash is applied to the motor rotation speed, the attenuation coefficient ξ _z is determined by the characteristics of the zero point of Gp (s). If it is smaller than 1, vibrations of about 1 to 3 Hz are excited and propagated to the motor torque command value by the filter processing by the filter (control block 701) of the transfer characteristic H (s) / Gp (s). The vibration of about 1 to 3 Hz appears in the vehicle as acceleration vibration and impairs a smooth stop. In the present embodiment, the deviation between the second motor torque estimated value and the first motor torque estimated value is caused. On the other hand, a disturbance torque estimated value Td is calculated by performing a filter process using a filter (control block 703) having a transfer characteristic Hz (s), so that as shown in each of FIGS. It is possible to smoothly decelerate and stop even in a scene across the gear backlash.

Here, in the above description, the second torque target value Tm2 ^* is calculated by adding the motor rotation speed F / B torque Tω and the disturbance torque estimated value Td, but the motor rotation speed F / B torque Tω is calculated. May be set as the second torque target value Tm2 ^* . FIG. 12 is a block diagram for realizing the stop control process when the motor rotational speed F / B torque Tω is set as the second torque target value Tm2 ^* . 12, the same components as those shown in FIG. 5 are denoted by the same reference numerals.

Even if you set the motor speed F / B torque Tω as the second torque target value Tm2 ^*, the second torque target value Tm2 ^* is determined to stop just before become the first torque target value Tm1 ^* greater As a result, the motor torque command value Tm ^* is switched from the first torque target value Tm1 ^* to the second torque target value Tm2 ^* . At this time, since the second torque target value Tm2 ^* is the same value as the motor rotation speed F / B torque Tω, the motor torque command value Tm ^* converges to zero as the motor rotation speed ωm decreases.

As described above, the control device for an electric vehicle in the embodiment is a control device for an electric vehicle that uses the electric motor 4 as a travel drive source and decelerates by the regenerative braking force of the electric motor 4, and detects the accelerator operation amount. A motor torque command value Tm ^* is calculated, and the electric motor 4 is controlled based on the calculated motor torque command value Tm ^* . In particular, when the accelerator operation amount is equal to or less than a predetermined value and the electric vehicle is about to stop, the motor torque command value Tm ^* is converged to zero as the rotational speed of the electric motor 4 decreases. Smooth deceleration without acceleration vibration in the vehicle can be realized just before stopping, and the stopped state can be maintained. In addition, since the vehicle can be decelerated to the stop state without using a brake braking force by a mechanical braking means such as a foot brake, the electric motor 4 can be regenerated even immediately before the stop, thereby improving the power consumption. be able to. Furthermore, since acceleration / deceleration and stopping of the vehicle can be realized only by the accelerator operation, it is not necessary to switch between the accelerator pedal and the brake pedal, and the burden on the driver can be reduced. Note that the accelerator operation amount is equal to or less than a predetermined value means that the accelerator operation when the vehicle is traveling at a sufficiently low speed (for example, a speed of 15 km / h or less) without intervention of a braking device, separately from regenerative braking. The amount is intended. Needless to say, the vehicle speeds mentioned in the examples are only examples.

  When the driver uses the brake pedal to stop the vehicle, a driver who is not used to driving depresses the accelerator pedal too much, and acceleration vibration occurs in the front-rear direction of the vehicle when the vehicle stops. In addition, in a vehicle that realizes acceleration / deceleration and stopping of the vehicle only by the accelerator operation, if it is attempted to reduce and stop at a constant deceleration, it is necessary to increase the deceleration in order to achieve sufficient deceleration during deceleration. Therefore, acceleration vibration occurs in the front-rear direction of the vehicle when the vehicle is stopped. However, according to the control device for an electric vehicle in one embodiment, any driver can realize smooth deceleration and stop by only the accelerator operation as described above.

In the control device for an electric vehicle according to the embodiment, the motor rotation speed ωm is detected, and the motor rotation speed feedback torque Tω is calculated by multiplying the detected motor rotation speed ωm by a predetermined gain Kvref. When the accelerator operation amount is equal to or less than a predetermined value and the electric vehicle is about to stop, the motor rotation speed feedback torque Tω is set as the motor torque command value Tm ^* . Since the motor rotation speed feedback torque Tω works as a viscosity (damper), the motor rotation speed ωm smoothly (asymptotically) converges to zero immediately before stopping. Thereby, the smooth stop without a shock in the longitudinal acceleration can be realized.

Furthermore, in the control apparatus for an electric vehicle according to the embodiment, the first torque target value Tm1 ^* is calculated based on the vehicle information, and the motor rotation speed feedback torque Tω is calculated as the second torque target value Tm2 ^*. The larger one of the first torque target value Tm1 ^* and the second torque target value Tm2 ^* is set as the motor torque command value Tm ^* . Thereby, after decelerating at the first torque target value Tm1 ^* based on the vehicle information, it is possible to realize a smooth stop from deceleration by switching to the second torque target value Tm2 ^* immediately before stopping. In addition, since the larger one of the first torque target value Tm1 ^* and the second torque target value Tm2 ^* is set as the motor torque command value Tm ^* , the torque target value is switched at any timing. A torque step does not occur and smooth deceleration can be realized.

Further, in the control apparatus for an electric vehicle in one embodiment, when the disturbance torque is estimated, the accelerator operation amount is equal to or less than a predetermined value, and the electric vehicle is about to stop, the motor torque command value is reduced along with a decrease in the motor rotation speed. Since Tm ^* is converged to disturbance torque estimate value Td, smooth deceleration without acceleration vibration in the front-rear direction can be realized just before stopping regardless of the uphill road, flat road, downhill road, and the stop state Can be held.

  The estimated disturbance torque Td is estimated as a positive value on an uphill road and a negative value on a downhill road, so that the vehicle can smoothly stop on a slope and can maintain a stopped state without requiring a foot brake. Further, since the estimated disturbance torque Td is estimated to be zero on a flat road, the vehicle can be stopped smoothly on the flat road, and the stopped state can be maintained without requiring a foot brake.

In the control apparatus for an electric vehicle in one embodiment, the motor rotation speed ωm is detected, and the motor rotation speed feedback torque Tω is calculated by multiplying the detected motor rotation speed ωm by a predetermined gain Kvref. When the accelerator operation amount is equal to or less than a predetermined value and the electric vehicle is about to stop, an added value of the motor rotation speed feedback torque Tω and the disturbance torque Td is calculated as a motor torque command value Tm ^* . Since the motor rotation speed feedback torque Tω acts as a viscosity (damper) on the dynamic characteristics from the motor torque to the motor rotation speed, the motor rotation speed ωm smoothly (asymptotically) converges to zero immediately before stopping. Thereby, the smooth stop which suppressed the vibration of the longitudinal acceleration is realizable.

  Further, since the disturbance torque is estimated based on the model Gp (s) of the torque input to the vehicle and the transmission characteristic of the rotational speed of the motor, the disturbance torque estimated value Td can be obtained with high accuracy.

In particular, H (s) composed of the model Gp (s) and a transfer characteristic H (s) in which the difference between the denominator order and the numerator order is equal to or greater than the difference between the denominator order and the numerator order of the model Gp (s). ) / Gp (s) is input to the filter having the transfer characteristic to calculate the first motor torque estimated value, and the motor torque command value Tm ^* is applied to the filter having the transfer characteristic H (s). The input is used to calculate a second motor torque estimated value, and a disturbance torque estimated value Td is obtained by calculating a deviation between the second motor torque estimated value and the first motor torque estimated value. Thereby, the disturbance torque estimated value Td can be obtained with high accuracy.

Further, when the numerator of the model Gp (s) is expressed by a quadratic expression, a second motor torque estimated value is obtained using a filter Hz (s) composed of the numerator of the quadratic expression and the denominator of the quadratic expression. The disturbance torque estimated value Td is obtained by performing a filtering process on the deviation between the first motor torque estimated value and the first motor torque estimated value. The quadratic expression of the numerator of the filter Hz (s) is a quadratic expression of the numerator of the model Gp (s), and the quadratic expression of the denominator of the filter Hz (s) is 2 of the numerator of the model Gp (s). This is a quadratic expression having a second attenuation coefficient ξ _c set to a value larger than the first attenuation coefficient ξ _z calculated from the following expression. When a disturbance including a modeling error with Gp (s) generated in a scene or the like straddling a gear backlash is applied to the motor rotation speed ωm, ξ _z is 1 due to the characteristics of the zero point of Gp (s). If it is smaller, vibration of about 1 to 3 Hz is excited by a filter process using a filter having a transfer characteristic of H (s) / Gp (s) and propagates to the motor torque command value. For this reason, the difference between the second motor torque estimated value and the first motor torque estimated value is filtered by the filter Hz (s), so that it can be smoothed even in a scene straddling a gear backlash. You can slow down and stop.

Moreover, since the second damping coefficient ξ _c is set to a value larger than 1, the vibration suppressing effect can be enhanced.

According to the control apparatus for the electric vehicle in the embodiment, the first torque target value Tm1 ^* is calculated based on the vehicle information, and the second torque converges to the disturbance torque estimated value Td as the motor rotational speed ωm decreases. The torque target value Tm2 ^* is calculated, and when the second torque target value Tm2 ^* becomes larger than the first torque target value Tm1 ^* , it is determined that the electric vehicle is about to stop, and the second torque target value Tm2 ^* Is set as the motor torque command value Tm ^* . Thereby, after decelerating at the first torque target value Tm1 ^* based on the vehicle information, it is possible to realize a smooth stop from deceleration by switching to the second torque target value Tm2 ^* immediately before stopping.

The present invention is not limited to the embodiment described above. For example, in the above description, when the accelerator operation amount is equal to or less than a predetermined value and the electric vehicle is about to stop, the motor torque command value Tm ^* is reduced to the disturbance torque estimated value Td (or the lower the rotational speed of the electric motor 4). It was explained that it converges to zero). However, since vehicle parameters (speed parameters) such as wheel speed, vehicle body speed, and drive shaft rotation speed are proportional to the rotation speed of the electric motor 4, the vehicle parameter decreases in proportion to the rotation speed of the electric motor 4. The motor torque command value Tm ^* may be converged to the disturbance torque estimated value Td (or zero).

  This application claims the priority based on Japanese Patent Application No. 2013-247407 for which it applied to Japan Patent Office on November 29, 2013, All the content of this application is integrated in this specification by reference.

Claims (9)

A control device for an electric vehicle using a motor as a travel drive source and capable of controlling from deceleration to stop of the vehicle by regenerative braking force of the motor,
An accelerator pedal for instructing acceleration / deceleration and stop of the vehicle;
An accelerator operation amount detection means for detecting an accelerator operation amount that is an operation state of the accelerator pedal;
Disturbance torque estimating means for estimating a disturbance torque acting on the motor;
Motor torque command value calculating means for calculating a motor torque command value;
Motor control means for controlling the motor based on the motor torque command value;
With
The disturbance torque estimating means estimates the disturbance torque based on a torque input to a vehicle and a model Gp (s) of transfer characteristics of the rotational speed of the motor,
The motor torque command value calculating means sets the rotation speed of the motor or the rotation speed of the motor when the accelerator operation amount becomes equal to or less than a predetermined value by operating the accelerator pedal and the electric vehicle is about to stop. Converging the motor torque command value to the disturbance torque with a decrease in the proportional vehicle parameter,
Control device for electric vehicle. In the control apparatus of the electric vehicle according to claim 1,
Motor rotation speed detection means for detecting the rotation speed of the motor;
Motor rotation speed feedback torque calculating means for calculating a motor rotation speed feedback torque by multiplying the rotation speed of the motor by a predetermined gain; and
The motor torque command value calculating means calculates an addition value of the motor rotation speed feedback torque and the disturbance torque when the accelerator operation amount is equal to or less than a predetermined value and the electric vehicle is about to stop. Set as
Control device for electric vehicle. In the control apparatus of the electric vehicle according to claim 2,
First torque target value calculating means for calculating a first torque target value based on vehicle information;
Second torque target value calculation means for calculating a second torque target value that converges on the disturbance torque with a decrease in the rotation speed of the motor or a vehicle parameter proportional to the rotation speed of the motor;
Torque comparison means for comparing the magnitudes of the first torque target value and the second torque target value;
Further comprising
The motor torque command value calculating means determines that the electric vehicle is about to stop when the second torque target value is larger than the first torque target value, and sets the second torque target value to the second torque target value. Set as motor torque command value,
Control device for electric vehicle. In the control apparatus of the electric vehicle as described in any one of Claims 1-3 ,
The disturbance torque estimating means estimates the disturbance torque as a positive value on an uphill road and a negative value on a downhill road,
Control device for electric vehicle. In the control apparatus of the electric vehicle as described in any one of Claims 1-4 ,
The disturbance torque estimating means sets the disturbance torque to zero on a flat road,
Control device for electric vehicle. In the control apparatus of the electric vehicle as described in any one of Claims 1-5 ,
The disturbance torque estimating means includes the model Gp (s) and a transfer characteristic H (s) in which the difference between the denominator order and the numerator order is equal to or greater than the difference between the denominator order and the numerator order of the model Gp (s). A first motor torque estimated value is calculated by inputting the rotational speed of the motor to a filter having a transfer characteristic of H (s) / Gp (s), and the transfer characteristic H (s) is provided. By inputting the motor torque command value to the filter to calculate a second motor torque estimated value, and calculating the deviation between the second motor torque estimated value and the first motor torque estimated value, the disturbance Estimate torque,
Control device for electric vehicle. In the control apparatus of the electric vehicle according to claim 6 ,
When the numerator of the model Gp (s) is expressed by a quadratic expression, the disturbance torque estimating means uses the filter Hz (s) composed of the numerator of the quadratic expression and the denominator of the quadratic expression. The disturbance torque is estimated by performing a filtering process on the deviation between the second motor torque estimated value and the first motor torque estimated value,
The quadratic expression of the numerator of the filter Hz (s) is the quadratic expression of the numerator of the model Gp (s), and the quadratic expression of the denominator of the filter Hz (s) is the quadratic expression of the model Gp (s). A quadratic expression having a second attenuation coefficient set to a value greater than the first attenuation coefficient calculated from the quadratic expression of the numerator;
Control device for electric vehicle. The control apparatus for an electric vehicle according to claim 7 ,
The second attenuation coefficient is a value greater than 1.
Control device for electric vehicle. A method for controlling an electric vehicle having a motor as a travel drive source, an accelerator pedal for instructing acceleration / deceleration and stop of the electric vehicle, and capable of controlling from deceleration of the vehicle to stopping by the regenerative braking force of the motor. And
Detecting an accelerator operation amount which is an operation state of the accelerator pedal;
Estimating a disturbance torque acting on the motor;
Calculating a motor torque command value;
Controlling the motor based on the motor torque command value;
With
In the step of estimating the disturbance torque, the disturbance torque is estimated based on a torque input to the vehicle and a model Gp (s) of transfer characteristics of the rotational speed of the motor,
In the step of calculating the motor torque command value, when the accelerator pedal operation is performed, the accelerator operation amount becomes a predetermined value or less, and when the electric vehicle is about to stop, the rotation speed of the motor or the rotation of the motor Converging the motor torque command value to the disturbance torque with a decrease in vehicle parameters proportional to speed,
Control method of electric vehicle.

Images