WO2015079574A1

WO2015079574A1 - Control device for electric vehicle and control method for electric vehicle

Info

Publication number: WO2015079574A1
Application number: PCT/JP2013/082248
Authority: WO
Inventors: 弘征小松; 伊藤　健; 中島　孝; 雄史勝又; 澤田　彰
Original assignee: 日産自動車株式会社
Priority date: 2013-11-29
Filing date: 2013-11-29
Publication date: 2015-06-04

Abstract

A control device for an electric vehicle in which a motor is a travel drive source and which decelerates using the regenerative braking force of the motor if the accelerator operation amount is decreased or is zero, wherein if the accelerator operation amount is decreased or is zero, a speed parameter which is proportional to the travelling speed of the electric vehicle is set so as to conform to a speed parameter target value which converges asymptotically to zero.

Description

Electric vehicle control device and electric vehicle control method

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

2. Description of the Related Art Conventionally, there is known a regenerative brake control device for an electric vehicle that is provided with setting means that can arbitrarily set a regenerative braking force of an electric motor, and regenerates the electric motor with a regenerative braking force set by the setting means (see JP 8-79907A) ).

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 the vehicle body when the electric vehicle is stopped with a regenerative braking force.

The control device for an electric vehicle according to an embodiment is a control device for an electric vehicle that uses a motor as a travel drive source and decelerates by the regenerative braking force of the motor when the accelerator operation amount decreases or becomes zero, and the accelerator operation amount decreases. Or when it becomes zero, the speed parameter proportional to the traveling speed of the electric vehicle is made to coincide with the speed parameter target value that asymptotically converges to zero.

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 apparatus 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 showing 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 block diagram for explaining a method of calculating the speed control torque Tω based on the motor rotation speed ωm and the motor rotation speed target value ωm ^* . FIG. 7 is a block diagram for explaining a method of setting the motor rotation speed target value ωm ^* . FIG. 8 is a diagram illustrating an example of the attenuation rate table. FIG. 9 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. 10 is a flowchart showing a flag setting procedure performed by the flag setter. FIG. 11 is a block diagram for setting the motor rotation speed target value ωm ^* with a configuration different from that in FIG. FIG. 12A is a diagram illustrating an example of a control result by the control device for the electric vehicle in the embodiment on the uphill road. FIG. 12B is a diagram illustrating an example of a control result by the control device for the electric vehicle in the embodiment on a flat road. FIG. 12C is a diagram illustrating an example of a control result by the control device for the electric vehicle in the embodiment on the downhill road. FIG. 13 is an enlarged view of the scale of the vertical axis of the motor rotation speed ωm graph shown in FIG. 12, and FIGS. 13 (a) to 13 (c) are cases where the vehicle stops on an uphill road, a flat road, and a downhill road, respectively. The control result is shown.

FIG. 1 is a block diagram illustrating a main configuration of an electric vehicle including an electric vehicle control device according to one 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.

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. Further, a drive signal for the inverter 3 is generated according to the generated PWM signal.

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

The electric motor 4 generates a driving force by the alternating current supplied from the inverter 3, and transmits the driving force to the left and

right driving wheels

9 a and 9 b via the speed reducer 5 and the drive shaft 8. 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 the three-phase alternating currents iu, iv, iw flowing through the electric motor 4. However, since the sum of the three-phase alternating currents iu, iv, and iw is 0, any two-phase current may be detected, and the remaining one-phase current may be obtained by calculation.

The rotation sensor 6 is, for example, a resolver or an encoder, and detects the rotor phase 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.

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.

The 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 and stop of the vehicle only by operating the accelerator pedal, and at least when 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 for controlling the electric vehicle to stop is performed. Specifically, when the motor rotation speed is higher than a predetermined value, the first torque target value Tm1 ^* calculated in step S202 is set as the motor torque command value Tm ^* . When the motor rotation speed is equal to or lower than a predetermined value, the second torque target value Tm2 ^* that converges to the disturbance torque estimated value Td as the motor rotation speed decreases is obtained by performing speed control described later. Set to Tm ^* . This 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, a stop state can be maintained irrespective of a gradient. 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. A non-interference voltage necessary for canceling the interference voltage between the dq orthogonal coordinate axes may be added 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 obtained in this way.

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 driving wheel M: vehicle weight K _d : torsional rigidity of driving system K _t : coefficient relating 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 symbols in the formulas (1) to (3) represents time differentiation.

When the transfer characteristic Gp (s) from the torque target value Tm of the electric motor 4 to the motor rotation speed ωm is obtained based on the equation of motion represented by the equations (1) to (5), it is expressed by the following equation (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 speed controller 501 calculates a speed control torque Tω for making the detected motor rotational speed ωm coincide with the motor rotational speed target value ωm ^* that asymptotically converges to zero.

FIG. 6 is a block diagram for explaining a process performed by the speed controller 501, that is, a method for calculating the speed control torque Tω based on the motor rotation speed ωm and the motor rotation speed target value ωm ^* .

The motor rotation speed target value setter 601 sets a motor rotation speed target value ωm ^* that is uniquely determined by the motor rotation speed ωm at the time of starting speed control. A method for setting the motor rotation speed target value ωm ^* will be described with reference to FIG.

The control block 701 obtains the reference torque Tref by multiplying the motor rotational speed target value ωm ^* by the gain Kvref. However, the gain Kvref is a negative (minus) value necessary for stopping the electric vehicle, and is appropriately set based on, for example, experimental data. Thus, the reference torque Tref is set as a torque that provides a larger regenerative braking force as the motor rotation speed target value ωm ^* is larger.

The control block 702 obtains the motor rotation speed target value ωm ^* by inputting the reference torque Tref obtained by the control block 701 into the model Gp (s). Since the reference torque Tref acts as a viscous (damper) element for the dynamic characteristics from the reference torque Tref to the motor rotational speed target value ωm ^* , the motor rotational speed target value ωm ^* is asymptotically smoothly zeroed immediately before stopping. Converge. Thereby, the smooth stop without a shock in the longitudinal acceleration can be realized.

Here, the model Gp (s) is initialized so that the motor rotation speed target value ωm ^* becomes the motor rotation speed ωm when the flag set by the flag setting unit 504 described later changes from 0 to 1. That is, when the flag set by the flag setting unit 504 changes from 0 to 1, the control block 702 changes the motor rotation speed when the flag changes from 0 to 1 (when the motor rotation speed ωm becomes a predetermined value or less). ωm is output as the motor rotation speed target value ωm ^* .

The model matching compensator 602 in FIG. 6 is a filter having a transfer characteristic of R ₁ (s) / (Gp (s) · (1−R ₁ (s))), and includes a motor rotation speed target value ωm ^* and a motor. By performing a filtering process on the difference from the rotational speed ωm, a speed control torque Tω for matching the motor rotational speed ωm with the motor rotational speed target value ωm ^* is calculated. Here, R ₁ (s) is a low-pass filter, and the time constant is set to an appropriate value by performing simulations and experiments in advance.

As shown in FIG. 7, the motor rotational speed target value setter 601 asymptotically approaches zero by applying a viscous (damper) element to the dynamic characteristics from the reference torque Tref to the motor rotational speed target value ωm ^*. The target motor speed ωm ^* that converges automatically is calculated, but control is started using a predetermined torque table for the motor speed ωm, an attenuation rate table that stores the attenuation rate of the motor speed ωm in advance, etc. The motor rotation speed target value ωm ^* corresponding to the time from may be calculated.

FIG. 8 is a diagram illustrating an example of the attenuation rate table. As shown in FIG. 8, the motor rotation speed target value ωm ^* is set to a value that converges asymptotically to zero as time passes from the initial value _{ωm_init} ^* . Motor rotation speed target value .omega.m ^* initial value .omega.m _{_init} ^* is the motor rotational speed .omega.m when the flag set by the flag setting unit 504 to be described later is changed from 0 to 1.

Returning to FIG. 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. 9 is a block diagram for explaining a process performed by the disturbance torque estimator 502, that is, a method for calculating the disturbance torque estimated value Td based on the motor rotation speed ωm and the motor torque command value Tm ^* .

The control block 901 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. H (s) is a low-pass filter having a transfer characteristic 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).

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 903 calculates the disturbance torque estimated value Td by subtracting the second motor torque estimated value from the first motor torque estimated value.

In the present embodiment, the disturbance torque is estimated by a disturbance observer as shown in FIG. 9, but may be estimated by 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 subtractor 503 calculates the second torque target value Tm2 ^* by calculating the deviation between the speed control torque Tω calculated by the speed controller 501 and the disturbance torque estimated value Td calculated by the disturbance torque estimator 502 ^. Is calculated.

Flag setter 504, the disturbance torque estimated value Td, the motor rotational speed .omega.m, and, based on the first torque target value Tm1 ^*, the motor torque command value Tm ^*, the first torque target value Tm1 ^* and the second A flag indicating which of the torque target value Tm2 ^* is to be set is set.

FIG. 10 is a flowchart showing a flag setting processing procedure performed by the flag setting unit 504. In step S1001, it is determined whether the relationship of following Formula (10) is materialized.

If it is determined that the relationship of Expression (10) holds, it is determined that the motor rotation speed is equal to or less than a predetermined value, and the process proceeds to step S1002, and if it is determined that the relationship of Expression (10) does not hold, the motor rotation speed is a predetermined value. It is determined that the value is higher, and the process proceeds to step S1003.

In step S1002, the flag is set to 1.

On the other hand, in step S1003, the flag is set to 0.

When the flag is set to 0, the motor torque command value setter 505 in FIG. 5 sets the first torque target value Tm1 ^* as the motor torque command value Tm ^* , and the flag is set to 1. If it is, the second torque target value Tm2 ^* is set as the motor torque command value Tm ^* . 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.

As described above, in the present embodiment, first, the difference between the motor rotation speed ωm and the motor rotation speed target value ωm ^* is input to the model matching compensator 602 and subjected to the filtering process, whereby the motor rotation speed ωm is obtained. A speed control torque Tω for matching with the motor rotation speed target value ωm ^* is calculated. Subsequently, a disturbance torque estimated value Td is calculated by a disturbance observer (see FIG. 9) based on the motor torque command value Tm ^* and the motor rotation speed ωm. Then, by setting the second torque target value Tm2 ^* calculated by subtracting the disturbance torque estimated value Td from the speed control torque Tω as the motor torque command value immediately before stopping (the motor rotation speed is a predetermined value or less), Only the motor torque is used, and the vehicle can be stopped smoothly without depending on the gradient, and the stopped state can be maintained.

Aside from such a configuration, a value obtained by filtering the difference between the motor rotation speed ωm and the motor rotation speed target value ωm ^* by a compensator including an integration operation such as PI control is used as a motor torque command value. The same effect can be obtained even with the configuration set to. Details of this configuration are shown in FIG.

In FIG. 11, a motor rotation speed target value setter 1101 sets a motor rotation speed target value ωm ^* by a method similar to the method performed by the motor rotation speed target value setter 601 shown in FIG.

The control block 1102 performs a filtering process on a difference between the motor rotation speed target value ωm ^* and the motor rotation speed ωm by a compensator including an integration operation, so that the motor rotation speed ωm and the motor rotation speed target value are obtained. A second torque target value Tm2 ^* that ωm ^* matches and compensates for disturbance torque is calculated. Kp and ki in the control block 1102 represent a proportional gain and an integral gain, respectively, and appropriate values are set by performing simulations and experiments in advance.

FIG. 12A to FIG. 12C are diagrams showing an example of a control result by the control device for an electric vehicle in one embodiment. 12A to 12C 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 shown in order from the top.

At times t0 and t1, the motor rotation speed is higher than a predetermined value, and the electric motor 4 is decelerated based on the first torque target value Tm1 ^* calculated in step S202 of FIG.

Time t2 is a timing at which the motor rotational speed becomes equal to or lower than a predetermined value and the flag is set to 1 by the flag setting unit 504. At this time t2, the motor torque command value Tm ^* is switched from the first torque target value Tm1 ^* to the second torque target value Tm2 ^* .

At time t3, as shown in FIGS. 12A to 12C, the motor torque command value Tm ^* converges to the disturbance torque estimated value Td regardless of the uphill road, the flat road, or the downhill road, and the motor rotation speed is asymptotic to zero. Converge to. Thereby, the smooth stop without the acceleration vibration of the front-back direction at the time of a stop is realizable. After time t3, the stopped state is maintained.

FIG. 13 is an enlarged view of the scale of the vertical axis of the motor rotation speed ωm graph shown in FIG. 12, and FIGS. 13 (a) to 13 (c) are cases where the vehicle stops on an uphill road, a flat road, and a downhill road, respectively. The control result is shown.

As is clear from FIGS. 13A to 13C, the timing (motor rotation speed) at which the speed control is started differs depending on the estimated disturbance torque Td that depends on the road surface gradient. In the example shown in FIG. 13, the speed control is started at the motor rotation speed ωm1 on the uphill road, but the speed control is started at the motor rotation speed ωm2 lower than the motor rotation speed ωm1 on the flat road. On the downhill road, speed control is started at a motor rotation speed ωm3 lower than the motor rotation speed ωm2.

As described above, according to the control device for an electric motor in one embodiment, the 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 when the accelerator operation amount decreases or becomes zero. Then, when the motor rotation speed target value ωm ^* that sets the motor rotation speed ωm asymptotically to zero is set, and the accelerator operation amount decreases or becomes zero, the motor rotation speed ωm is changed to the motor rotation speed target value ωm. Control to match ^* . Thereby, on a flat road, smooth deceleration without acceleration vibration in the front-rear direction can be realized, and a 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.

When the driver stops the vehicle using the brake pedal, the 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 particular, according to the motor control device in one embodiment, when the accelerator operation amount decreases or becomes zero and the motor rotation speed ωm is equal to or less than a predetermined value, the motor rotation speed ωm asymptotically converges to zero. Control to match the motor rotation speed target value ωm ^* is performed. As a result, when the motor rotational speed ωm is higher than the predetermined value and when it is lower than the predetermined value, different motor rotational speed target values, that is, deceleration of the vehicle can be set, and smoother deceleration can be achieved. Can be realized.

Further, the motor rotational speed .omega.m at the time of starting the control to match the motor rotational speed target value .omega.m ^* to asymptotically converge to zero motor speed .omega.m, so set the initial value of the motor rotational speed target value .omega.m ^* Thus, before and after the start of control for matching the motor rotation speed ωm to the motor rotation speed target value ωm ^* that asymptotically converges to zero, a torque step does not occur, and a smooth stop can be realized from the deceleration state.

Further, since the predetermined value to be compared with the motor rotational speed ωm is determined based on the estimated disturbance torque Td, control for matching the motor rotational speed ωm to the motor rotational speed target value ωm ^* that asymptotically converges to zero is started. The timing to perform can be changed according to the disturbance torque estimated value Td. As a result, a torque step does not occur before and after the start of control for making the motor rotation speed ωm coincident with the motor rotation speed target value ωm ^* that asymptotically converges to zero, regardless of the road surface gradient. A stop can be realized.

According to the motor control device in one embodiment, when the accelerator operation amount decreases or becomes zero, the motor torque is converged to the disturbance torque estimated value Td as the motor rotation speed ωm decreases. Accordingly, smooth deceleration without acceleration vibration in the front-rear direction can be realized just before the stop regardless of the uphill road, the flat road, and the downhill road, and the stop state can be maintained.

Since the disturbance torque is estimated as a positive value on an uphill road and a negative value on a downhill road, the disturbance torque can be smoothly stopped even on a slope road, and the stopped state can be maintained without requiring a foot brake. Further, since the disturbance torque is estimated as 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. Here, the disturbance torque is a torque value necessary to cancel the disturbance torque, and the sign is inverted with respect to the estimated value Td calculated by the disturbance torque estimator 502 in FIG. Value. That is, the second torque target value Tm2 ^* when the speed control torque Tω is zero.

In addition, according to the motor control apparatus in one embodiment, the motor rotational speed target value that asymptotically converges to zero based on the torque input to the vehicle and the model Gp (s) of the transmission characteristic of the rotational speed of the motor. Set ωm ^* . Specifically, since the motor rotation speed target value ωm ^* is calculated by inputting the arbitrarily determined reference torque to the model Gp (s), a smooth stop can be realized.

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

Since the disturbance torque estimated value Td used for determining a predetermined value to be compared with the motor rotation speed ωm and the disturbance torque estimated value Td used for converging the motor torque to the disturbance torque estimated value Td are shared, the calculation load is reduced. Can be reduced.

The present invention is not limited to the embodiment described above. For example, in the above-described embodiment, when the accelerator operation amount decreases or becomes zero, the control is performed so that the motor rotation speed ωm is matched with the motor rotation speed target value ωm ^* that asymptotically converges to zero. . However, since speed parameters such as wheel speed, vehicle speed, and drive shaft rotation speed are proportional to the motor rotation speed ωm, control is performed so that the speed parameter matches the speed parameter target value that asymptotically converges to zero. It may be.

Claims

A control device for an electric vehicle that uses a motor as a travel drive source and decelerates by the regenerative braking force of the motor when the accelerator operation amount decreases or becomes zero,
An accelerator operation amount detection means for detecting the accelerator operation amount;
Speed parameter detecting means for detecting a speed parameter proportional to the traveling speed of the electric vehicle;
Speed parameter target value setting means for setting a speed parameter target value for asymptotically converging the speed parameter to zero;
Speed control means for matching the speed parameter with the speed parameter target value when the accelerator operation amount decreases or becomes zero;
The control apparatus of the electric vehicle provided with.
In the control apparatus of the electric vehicle according to claim 1,
The speed control means performs control to match the speed parameter with the speed parameter target value when the accelerator operation amount decreases or becomes zero and the speed parameter becomes a predetermined value or less.
Control device for electric vehicle.
In the control apparatus of the electric vehicle according to claim 2,
The speed parameter target value setting means sets a speed parameter when starting control for causing the speed control means to match the speed parameter to the speed parameter target value as an initial value of the speed parameter target value.
Control device for electric vehicle.
In the control apparatus of the electric vehicle according to claim 2 or claim 3,
A disturbance torque estimating means for estimating the disturbance torque;
Determining the predetermined value based on the estimated disturbance torque;
Control device for electric vehicle.
In the control apparatus of the electric vehicle according to claim 1,
A disturbance torque estimating means for estimating the disturbance torque;
The speed control means includes torque control means for converging the motor torque to the estimated disturbance torque together with a decrease in the speed parameter when the accelerator operation amount decreases or becomes zero.
Control device for electric vehicle.
In the control apparatus of the electric vehicle according to claim 5,
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 according to claim 5 or 6,
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 5-7,
The speed parameter target value setting means sets the speed parameter target value based on a torque input to the vehicle and a model Gp (s) of a transfer characteristic of the rotational speed of the motor.
Control device for electric vehicle.
In the control apparatus of the electric vehicle as described in any one of Claims 5-8,
The disturbance torque estimation means estimates the disturbance torque based on a model Gp (s) of transmission characteristics of torque input to the vehicle and the rotational speed of the motor.
Control device for electric vehicle.
In the control apparatus of the electric vehicle as described in any one of Claims 5-9,
Determining the predetermined value based on the estimated disturbance torque;
Control device for electric vehicle.
In the control apparatus of the electric vehicle as described in any one of Claims 1-10,
The speed parameter is a rotation speed of the motor.
Control device for electric vehicle.
A control method for an electric vehicle that uses a motor as a travel drive source and decelerates by the regenerative braking force of the motor when the accelerator operation amount decreases or becomes zero.
Detecting the accelerator operation amount;
Detecting a speed parameter proportional to the traveling speed of the electric vehicle;
Setting a speed parameter target value for asymptotically converging the speed parameter to zero;
When the accelerator operation amount decreases or becomes zero, the speed parameter is matched with the speed parameter target value;
An electric vehicle control method comprising: