JP7056219B2 - Motor vehicle control method and motor vehicle control device - Google Patents

Description

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

In Patent Document 1, when the accelerator opening is constant, the disturbance torque estimates the external force (running resistance) input to the driving motor in order to keep the deceleration of the electric vehicle constant regardless of the slope of the road surface. A control device for an electric vehicle that is calculated as a value and controls a regenerative braking amount generated in a motor based on an estimated disturbance torque is disclosed. According to this control device for the electric vehicle, when the accelerator opening degree is constant, it is possible to suppress changes in the acceleration / deceleration speed and the vehicle speed according to the change in the gradient of the traveling road surface.

On the other hand, Patent Document 2 provides a setting means capable of arbitrarily setting the regenerative braking force of the motor, and regenerates for an electric vehicle that increases or decreases the regenerative braking amount generated in the motor according to the value set by the setting means. Brake control devices are disclosed.

Patent No. 6135775 Japanese Unexamined Patent Publication No. 8-79907

Here, if the technique disclosed in Patent Document 1 is simply applied with the setting means capable of arbitrarily setting the regenerative braking force as disclosed in Patent Document 2, the following problems occur. That is, even if the regenerative braking force according to the driver's intention is set through the setting means, the disturbance torque estimated value changes depending on the gradient of the traveling road surface, so that the actual regeneration is performed according to the change of the disturbance torque estimated value. The braking force changes. As a result, there is an excess or deficiency between the regenerative braking force set according to the driver's intention and the actual regenerative braking force controlled based on the estimated disturbance torque, which gives the driver a sense of discomfort.

INDUSTRIAL APPLICABILITY The present invention can control the regenerative braking force generated in the motor without giving a sense of discomfort to the driver even on a slope road in consideration of the traveling resistance input to the motor and the regenerative braking force set by the driver. The purpose is to provide the technology that can be used.

The method for controlling an electric vehicle according to the present invention includes a motor for driving the vehicle, an operating means for instructing acceleration / deceleration of the vehicle, and a regenerative level setting means for arbitrarily setting the strength of the regenerative braking force generated by the motor. It is a control method of an electric vehicle provided. In the control method, the basic torque target value is calculated according to the operation amount of the operating means, the traveling resistance acting on the motor is estimated, the correction gain according to the set value of the regenerative level setting means is calculated, and the traveling resistance is calculated. The running resistance correction torque is calculated based on the correction gain. Then, the final torque target value is calculated from the basic torque target value and the running resistance correction torque, and the motor is controlled according to the final torque target value.

According to the present invention, the motor is controlled by the final torque target value considering the correction gain according to the set value of the regenerative level setting means and the estimated running resistance, so that the driver feels uncomfortable even on a slope road. It is possible to control the regenerative braking force of the motor without using it.

FIG. 1 is a block diagram showing a main configuration of an electric vehicle provided with a control device for an electric vehicle according to an embodiment. FIG. 2 is a flowchart showing the flow of processing of motor current control performed by the motor controller. FIG. 3 is a diagram showing an example of an accelerator opening degree-torque table. FIG. 4 is a control block diagram for calculating the first torque target value. FIG. 5 is a diagram showing an example of an accelerator opening degree-torque table. FIG. 6 is a diagram showing an example of an accelerator opening degree-torque table. FIG. 7 is a control block diagram for calculating the third correction gain and the disturbance correction amount. FIG. 8 is a diagram showing the relationship between the accelerator opening degree and the first correction gain. FIG. 9 is a diagram showing the relationship between the regeneration mode and the second correction gain. FIG. 10 is a control block diagram for calculating a motor rotation speed FB torque target value. FIG. 11 is a diagram modeling a driving force transmission system of a vehicle. FIG. 12 is a control block diagram for realizing the stop control process. FIG. 13 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. 14 is a block diagram for explaining a method of calculating a disturbance torque estimated value Td based on a motor rotation speed ωm and a motor torque command value Tm ^* . FIG. 15 is a time chart showing the control results of the reference example on the downhill road. FIG. 16 is a time chart showing a control result of one embodiment on a downhill road. FIG. 17 is a time chart showing the control results of the reference example on the uphill road. FIG. 18 is a time chart showing a control result of one embodiment on an uphill road.

[One Embodiment]
FIG. 1 is a block diagram showing a main configuration of an electric vehicle provided with a control device for an electric vehicle according to an embodiment. The control device for an electric vehicle of the present invention is applicable to an electric vehicle that includes an electric motor as a part or all of the 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 according to the present embodiment can be applied to a vehicle that can control acceleration / deceleration and stop of the vehicle only by operating the accelerator pedal. In this vehicle, the driver depresses the accelerator pedal when accelerating, and when decelerating or stopping, the amount of depressing the accelerator pedal is reduced or the amount of depressing the accelerator pedal is set to zero.

The motor controller 2 is composed of, for example, a central processing unit (CPU), a read-only memory (ROM), a random access memory (RAM), and an input / output interface (I / O interface). The motor controller 2 has a vehicle state such as a vehicle speed V, an accelerator opening AP, a rotor phase α of an electric motor (three-phase AC motor) 4, currents iu, iv, iwa of the electric motor 4, and a regeneration mode changeover switch signal. Is input as a digital signal, and a PWM signal for controlling the electric motor 4 is generated based on the input signal. Further, the motor controller 2 generates a drive signal of the inverter 3 according to the generated PWM signal.

The inverter 3 converts the direct current supplied from the battery 1 into alternating current by turning on / off two switching elements (for example, power semiconductor elements such as IGBTs and MOS-FETs) provided for each phase. Alternatively, it is reversely converted and a desired current is passed through the electric motor 4.

The electric motor 4 (hereinafter, also simply referred to as “motor 4”) generates a driving force by an alternating current supplied from the inverter 3, and is connected to the left and right drive wheels 9a and 9b via the speed reducer 5 and the drive shaft 8. Transmits the driving force. Further, the electric motor 4 recovers the kinetic energy of the vehicle as electric energy by generating a regenerative driving force when the vehicle is rotated by being rotated by the drive wheels 9a and 9b while the vehicle is traveling. In this case, the inverter 3 converts the alternating current generated during the regenerative operation of the electric motor 4 into a direct current and supplies it to the battery 1.

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

The regenerative mode changeover switch 10 is a switch for the driver to set the strength of the regenerative braking force. More specifically, the regenerative mode changeover switch 10 (hereinafter referred to as "regenerative mode changeover SW10") is a switch for setting the strength of the regenerative torque when the accelerator opening is fully closed. That is, according to the regenerative mode changeover switch 10, the strength (magnitude) of the regenerative braking force with respect to the motor rotation speed ωm when the accelerator opening is fully closed can be arbitrarily set. The regenerative mode changeover switch 10 is preferably provided, for example, in the vicinity of the steering so that the driver can easily operate the switch even during operation. Further, the regenerative mode switching SW10 may be realized by a paddle switch integrally configured with the steering wheel so that the driver can operate more easily even during operation. The driver can intentionally increase or decrease the regenerative torque generated in the motor 4 by operating the regenerative mode switching SW10. The mode selected by the regeneration mode switching SW10 is input to the motor controller 2 as the regeneration mode setting value.

The accelerator pedal 11 instructs the vehicle to accelerate or decelerate by depressing the driver.

FIG. 2 is a flowchart showing a flow of processing of motor current control performed by the motor controller 2. The processes according to steps S201 to S205 are programmed to be constantly executed at regular intervals while the vehicle system is running.

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 direct current flowing through the electric motor 4. The currents iu, iv, iwa, and the 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 vehicle speed v (m / s) is obtained by multiplying the rotor mechanical angular velocity ωm by the tire driving radius R and dividing by the gear ratio of the final gear, and the unit is converted by multiplying by 3600/1000 to convert the vehicle speed. Find V (km / h).

The accelerator opening degree θ corresponds to the amount of operation of the accelerator pedal 11. The accelerator opening degree θ is acquired from an accelerator opening degree sensor (not shown) or 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 the motor rotational speed ωm (rad / rad /) which is the mechanical angular speed of the electric motor 4 by dividing the rotor angle speed ω (electric angle) by the pole log number p of the electric motor 4. s) is obtained, and it is obtained by multiplying the obtained motor rotation speed ωm by 60 / (2π). The rotor angular velocity ω is obtained by differentiating the rotor phase α.

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

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

In step S202, the first torque target value Tm1 ^* is set. Specifically, the torque table target value is set by referring to the accelerator opening degree-torque table shown in FIG. 3 based on the accelerator opening degree θ and the motor rotation speed ωm input in step S201. Next, the disturbance correction amount is calculated from the disturbance torque estimated value Td estimated by the disturbance torque estimator 802 using the disturbance correction torque setting device 803 described later. Then, the first torque target value Tm1 ^* is set by adding the disturbance correction amount to the torque table target value. Details of the process for calculating the first torque target value Tm1 ^* executed in this step will be described later.

In step S203, a stop control process for controlling the stop of the electric vehicle is performed. Specifically, it is determined when the electric vehicle is about to stop, and before the stop, the first torque target value Tm1 ^* calculated in step S202 is set to the motor torque command value Tm ^* , and after the stop, the motor rotates. The second torque target value Tm2 ^* that converges to the disturbance torque estimated value Td as the speed decreases is set to the motor torque command value Tm ^* . This second torque target value Tm2 ^* is a positive torque on an uphill road, a negative torque on a downhill road, and is almost zero on a flat road. As a result, as will be described later, the stopped state can be maintained regardless of the slope of the road surface. The 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 command 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, and the DC voltage value, and the d-axis current target value and the q-axis current target value, by referring to this table. Obtain the d-axis current target value id ^* and the q-axis current target value iq ^* .

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. Therefore, first, the d-axis current id and the q-axis current iq are obtained based on the three-phase AC current values iu, iv, and iwa input in step S201 and the rotor phase α of the electric motor 4. Subsequently, the d-axis and q-axis voltage command values vd and vq are calculated from the deviations between the d-axis and q-axis current command values id ^* and iq ^* and the d-axis and q-axis currents id and iq. The non-interference voltage required 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, the three-phase AC voltage command values vu, vv, and vw are obtained from the d-axis and q-axis voltage command values vd and vq and the rotor phase α of the electric motor 4. Then, the PWM signals tu (%), tv (%), and tw (%) are obtained from the obtained three-phase AC voltage command values vu, vv, vw and the DC voltage value Vdc. By opening and closing the switching element of the inverter 3 by the PWM signals tu, tv, and tw thus obtained, the electric motor 4 can be driven with a desired torque instructed by the torque command value Tm ^* .

Hereinafter, the first torque target value calculation process performed in step S202 of FIG. 2 will be described.

<First torque target value calculation process>
FIG. 4 is a block diagram for realizing the first torque target value calculation process.

The first torque target value Tm1 ^* of the present embodiment is an accelerator opening torque table 801, a disturbance torque estimator 802, a disturbance correction torque setting device 803, a rotation speed FB torque calculator 804, a switch 805, and an adder 806. Is calculated using.

In the accelerator opening torque table 801, the torque table target value is calculated from the accelerator opening degree θ and the motor rotation speed ωm by referring to the accelerator opening degree-torque table corresponding to the regeneration mode set value. In addition to FIG. 3 described above, the accelerator opening torque table 801 further stores an accelerator opening-torque table as shown in FIGS. 5 and 6. Each of these accelerator opening-torque tables corresponds to a regeneration level set value (regeneration mode) set by the driver via the regeneration mode switching SW10. As shown in the figure, each accelerator opening-torque table has a different magnitude of motor torque (regenerative torque) with respect to the motor rotation speed ωm when the accelerator opening is fully closed. That is, the accelerator opening torque table 801 sets the torque table target value from the accelerator opening degree θ and the motor rotation speed ωm with reference to the accelerator opening degree-torque table corresponding to the regeneration mode set value.

Here, the regeneration mode switching SW10 of the present embodiment is configured to be capable of switching in three stages of a strong regeneration mode, a weak regeneration mode, and a constant speed mode. Therefore, in the accelerator opening torque table 801 of the present embodiment, when the driver selects the strong regeneration mode, the accelerator opening-torque table shown in FIG. 3 is referred to, and when the driver selects the weak regeneration mode, the figure is shown. When the driver selects the constant speed mode with reference to the accelerator opening degree-torque table shown in FIG. 5, the torque table target value is calculated with reference to the accelerator opening degree-torque table shown in FIG. The constant speed mode is a mode that enables the vehicle to travel at a constant speed even if the traveling road surface is a sloped road when the accelerator opening degree is constant. That is, in the constant speed mode of the present embodiment, control for canceling the running resistance mainly caused by the gradient is executed by the regenerative torque generated in the motor 4. The control in the constant speed mode of this embodiment will be described later.

The number of modes that can be set by the regeneration mode switching SW10 is not limited to the three stages of the strong regeneration mode, the weak regeneration mode, and the constant speed mode, and the number of modes may be appropriately set as long as the constant speed mode is provided. ..

The disturbance torque estimator 802 estimates the disturbance torque estimation value Td as a value corresponding to the running resistance acting on the motor based on the motor torque command value Tm ^* and the motor rotation speed ωm. Details of the disturbance torque estimator 802 will be described later with reference to FIG.

The disturbance correction torque setting device 803 calculates the correction gain based on the accelerator opening degree θ and the regenerative mode set value, and calculates the disturbance correction amount based on the disturbance torque estimated value Td. Details will be described with reference to FIG. 7.

FIG. 7 is an example of a control block that realizes the disturbance correction torque setting device 803, and is a diagram for explaining a method of calculating the correction gain and the disturbance correction amount.

The disturbance correction torque setting device 803 includes an accelerator opening degree correction gain calculator 1101, a regeneration mode correction gain calculator 1102, a multiplier 1103, and a multiplier 1104.

The accelerator opening degree correction gain calculator 1101 calculates the first correction gain based on the accelerator opening degree θ. The first correction gain is calculated based on FIG. 8, which shows the relationship between the accelerator opening degree and the first correction gain. That is, the first correction gain is calculated so that 1 is the maximum value and the value becomes smaller as the accelerator opening degree θ increases. The calculated first correction gain is output to the multiplier 1103.

The regenerative mode correction gain calculator 1102 calculates the second correction gain based on the regenerative mode set value. The second correction gain is calculated based on FIG. 9, which shows the relationship between the regenerative mode set value and the second correction gain. That is, the second correction gain is set to 1 when the setting value of the regeneration mode is a constant speed, with 1 as the maximum value, and the setting is small when the setting value of the other setting values (weak regeneration, strong regeneration) is set. The larger the value (the smaller the regenerative braking force), the larger the value. Although the magnitude of the second correction gain corresponding to each set value is an example, it is preferably set in consideration of the driver fielding. Further, the smaller the regenerative braking force set by the driver, the closer the driver's intention is to traveling at a constant speed from the braking side. Therefore, according to the driver's intention, the disturbance correction amount can be switched more smoothly by increasing the correction gain as the regenerative braking force is smaller.

The calculated second correction gain is output to the multiplier 1103. As described above, the setting value of the regeneration mode may be appropriately set. Therefore, for example, when the set value of the regeneration mode can be set in a larger number of stages, the second correction gain is set to 1 (maximum value) when the set value is a constant speed, and for other set values. Is set stepwise to a larger value as the regenerative braking force corresponding to the set value is smaller.

The multiplier 1103 calculates the third correction gain by multiplying the first correction gain and the second correction gain. The third correction gain is output to the multiplier 1104 and is output to the rotation speed FB torque calculator 804 and the basic torque target value switcher 805 as the output of the disturbance correction torque setting device 803 (see FIG. 4).

The multiplier 1104 calculates the disturbance correction amount by multiplying the third correction gain and the disturbance torque estimated value Td. The calculated disturbance correction amount is output to the adder 806 (see FIG. 4).

The explanation will be continued by returning to FIG. The rotation speed FB torque calculator 804 calculates the rotation speed FB torque target value based on the motor rotation speed ωm and the third correction gain. The method of calculating the rotation speed FB torque target value will be described with reference to FIG.

FIG. 10 is an example of a control block that realizes the rotation speed FB torque calculator 804, and is a diagram for explaining a method of calculating a rotation speed FB torque target value.

The rotation speed FB torque calculator 804 includes a target motor rotation speed calculator 1401, a subtractor 1402, and a gain multiplier 1403.

The target motor rotation speed calculator 1401 calculates the target motor rotation speed based on the motor rotation speed ωm and the third correction gain. Specifically, the target motor rotation speed calculator 1401 sets the motor rotation speed ωm at the timing when the third correction gain changes from a value less than 1 to 1 as the target motor rotation speed, and sets the subtractor 1402. Output. The timing for setting the target motor rotation speed does not necessarily have to coincide with the timing when the third correction gain changes from a value less than 1 to 1. If it is within a sensually acceptable range from the viewpoint of drivability, the motor rotation speed ωm at the timing when a predetermined time elapses from the timing when the third correction gain changes from a value less than 1 to 1 is set as the target motor rotation speed. You may.

The subtractor 1402 calculates the deviation between the target motor rotation speed and the motor rotation speed ωm, and outputs the calculated value (motor rotation speed deviation) to the gain multiplier 1403.

In the gain multiplier 1403, the rotation speed FB torque target value is calculated by multiplying the motor rotation speed deviation output from the subtractor 1402 by the rotation speed FB gain K. The calculated rotation speed FB torque target value is output to the switch 805 (see FIG. 4). The rotation speed FB gain K is appropriately set for the purpose of improving the follow-up performance to the target motor rotation speed in the feedback (FB) control using the motor rotation speed ωm.

The explanation will be continued by returning to FIG. In the basic torque target value switch 805, either the rotation speed FB torque target value or the torque table target value is set as the basic torque target value based on the third correction gain. Specifically, in the switch 805, when the third correction gain is less than 1, the torque table target value calculated by the accelerator opening torque table 801 is set as the basic torque target value, and the third correction gain is 1. At the time, the rotation speed FB torque target value calculated by the rotation speed FB torque calculator 804 is set as the basic torque target value. The basic torque target value for which any value is set is output to the adder 806.

Then, in the adder 806, the first torque target value Tm ^* is calculated by adding the disturbance correction amount output from the disturbance correction torque setting device 803 to the basic torque target value.

The above is the details of the first torque target value Tm ^* calculation process executed in step S202 of FIG. Hereinafter, the stop control process executed in step S203 of FIG. 2 will be described.

<Stop control>
First, the vehicle response Gp (s) from the motor torque Tm to the motor rotation speed ωm in the present embodiment will be described. The vehicle response Gp (s) is used as a vehicle model that models the driving force transmission system of the vehicle in the stop control process including the estimation of the disturbance torque.

FIG. 11 is a diagram modeling a vehicle driving force transmission system, and each parameter in the figure is as shown below.
J _m : Motor inertia J _w : Drive wheel inertia M: Vehicle weight K _d : Drive system torsional rigidity K _t : Coefficient related to friction between tire and road surface N: Overall gear ratio r: Tire load radius ω _m : Motor rotation speed T _m ^* : Motor torque command value T _d : Drive wheel torque F: Force applied to the vehicle V: Vehicle speed ω _w : Drive wheel angular velocity

Then, from FIG. 11, the following equation of motion can be derived.

When the vehicle response Gp (s) from the motor torque Tm to the motor rotation speed ωm is obtained based on the equations of motion represented by the equations (1) to (5), it is expressed by the following equation (6).

However, a ₃ , a ₂ , a _1, a _0, b ₃ , b ₂ , b ₁ , b ₀ in the equation (6) are represented by the following equation (7).

By examining the poles and zeros of the transfer function shown in Eq. (6), it can be approximated to the transfer function shown in Eq. (8), and one pole and one zero point show extremely close values. This corresponds to the fact that α and β in the following equation (8) show extremely close values.

Therefore, by performing the extreme zero cancellation (approximate to α = β) in the equation (8), as shown in the following equation (9), G _p (s) is of (second order) / (third order). Consists of transmission characteristics.

Subsequently, the details of the stop control process will be described with reference to FIGS. 12 to 14.

FIG. 12 is a block diagram for realizing the stop control process. The stop control process is executed by using the motor rotation speed F / B torque setting device 501, the disturbance torque estimator 502, the subtractor 503, and the torque comparator 504 included in the motor controller 2.

The motor rotation speed F / B torque setting device 501 calculates the motor rotation speed feedback torque Tω (hereinafter referred to as motor rotation speed F / B torque Tω) based on the motor rotation speed ωm transmitted from the motor controller 2. .. Details will be described with reference to FIG.

FIG. 13 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 setting device 501 includes a multiplier 601 and calculates the motor rotation speed F / B torque Tω by multiplying the motor rotation speed ωm by the 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. The motor rotation speed F / B torque Tω is set as a torque at which a larger braking force can be obtained as the motor rotation speed ωm increases.

Although the motor rotation speed F / B torque setting device 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 regenerative torque with respect to the motor rotation speed ωm has been described. The motor rotation speed F / B torque Tω may be calculated by using a regenerative torque table in which the above is specified, a damping rate table in which the attenuation rate of the motor rotation speed ωm is stored in advance, or the like.

The disturbance torque estimator 502 shown in FIG. 12 calculates the disturbance torque estimation value T _d based on the motor rotation speed ωm transmitted from the motor controller 2 and the motor torque command value Tm ^* . In this embodiment, the disturbance torque estimator 502 described here and the disturbance torque estimator 802 described above with reference to FIG. 4 are the same. Details of the disturbance torque estimator 502 will be described with reference to FIG.

FIG. 14 is a block diagram for explaining a method of calculating a disturbance torque estimated value T _d based on a motor rotation speed ωm and a motor torque command value Tm ^* . The disturbance torque estimator 502 includes a control block 701, a control block 702, and a subtractor 703.

The control block 701 functions as a filter having a transmission characteristic of H (s) / G _p (s), and by performing a filtering process on the motor rotation speed ωm, a first motor torque estimated value is obtained. Is calculated. H (s) is a low-pass filter having a transmission 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 vehicle response G _p (s) (see equation (9)). ..

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

Then, the subtractor 703 calculates the deviation between the first motor torque estimated value and the second motor torque estimated value, thereby calculating the disturbance torque estimated value Td, which is a parameter representing the running resistance acting on the vehicle. Will be done.

The disturbance torque estimated value Td calculated as described above is estimated by the disturbance observer as shown in FIG. 12, but may be estimated by using a measuring instrument such as a vehicle front-rear G sensor.

Here, as the running resistance (disturbance) acting on the vehicle, air resistance, modeling error due to fluctuation of the vehicle mass due to the number of occupants and the load capacity, rolling resistance of the tire, gradient resistance of the road surface, etc. can be considered. Gradient resistance is the dominant disturbing factor just before a stop or at the initial start. Although the disturbance factor differs depending on the operating 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 G _p (s). Therefore, the above-mentioned disturbance factors can be estimated collectively. As a result, it is possible to realize a smooth stop from deceleration under any operating conditions.

The running resistance (estimated value of disturbance torque) is positive torque on flat roads due to the effects of rolling resistance and air resistance, and gradient resistance is added to flat roads on uphill roads. Become. Further, on a downhill road, the influence of the gradient resistance is subtracted from the rolling resistance, the air resistance, and the like, so that the torque is equal to or less than that of the flat road.

The explanation will be continued by returning to FIG. The subtractor 503 calculates the deviation between the motor rotation speed F / B torque Tω calculated by the motor rotation speed F / B torque setter 501 and the disturbance torque estimated value Td calculated by the disturbance torque estimator 502. The second torque target value Tm2 ^* is calculated by. When the motor rotation speed ωm decreases and approaches 0, the motor rotation speed F / B torque Tω also approaches 0. Therefore, the second torque target value Tm2 ^* is estimated as a disturbance torque according to the decrease in the motor rotation speed ωm. It converges to the value Td.

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 is about to stop (the vehicle speed is equal to or less than the predetermined vehicle speed), the first torque target value Tm1 ^* Will be larger 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 about to stop and sets the first torque target value Tm1 ^* as the motor torque command value. Set as Tm ^* . Further, the torque comparator 504 determines that the vehicle is about to stop when the second torque target value Tm2 ^* becomes larger than the first torque target value Tm1 ^* , and determines that the vehicle is about to stop, and the second torque target value Tm1 ^* is not used. The torque target value Tm2 ^* of is set as the motor torque command value Tm ^* . In order to maintain the stopped state, the second torque target value Tm2 ^* converges to a positive torque on an uphill road, a negative torque on a downhill road, and almost zero on a flat road.

The above is the details of the stop control process. By performing such a process, the vehicle can be smoothly stopped only by the motor torque and the stopped state can be maintained regardless of the slope of the road surface on which the vehicle is traveling.

Hereinafter, the effect when the control device for the electric vehicle of the present embodiment is applied to the vehicle will be described with reference to FIGS. 15 to 18.

15 and 16 are time charts when decelerating on a downhill road with the accelerator opening fully closed. FIG. 15 shows the control result by the reference example, and FIG. 16 shows the control result by the control device of the electric vehicle in this embodiment.

15 and 16 show the basic torque target value, the disturbance correction amount, the motor rotation speed ωm, and the vehicle front-rear acceleration in order from the top. Further, in both the reference example and the present embodiment, the driver uses the regeneration mode switching SW10 to set the strong regeneration mode from time t0 to t1, the weak regeneration mode from time t1 to t3, and the constant speed mode after time t3. Shall be selected.

First, FIG. 15, which is a control result of the reference example, will be described. In the reference example, unlike the present invention, the disturbance correction amount is constant even if the regeneration mode is switched by the driver. Therefore, in the reference example described below, the correction gain multiplied by the disturbance correction amount is fixed to the value (0.5) set in consideration of the driver feeling in the strong regeneration mode (this). Corresponds to the second correction gain of FIG. 9 in the embodiment).

At time t0, the strong regeneration mode is selected as the initial setting, so the disturbance correction amount is calculated by multiplying the estimated value of the disturbance torque by 0.5 as the correction gain when the strong regeneration mode is selected. .. Then, the vehicle is decelerated by the first torque target value obtained by adding the disturbance correction amount to the basic torque target value reflecting the driver's intention (strong regeneration mode) toward time t1.

At time t1, the driver is switched to the weak regeneration mode by operating the regeneration mode switching SW, and the basic torque target value is increased accordingly. However, since the correction gain does not change from 0.5, the disturbance correction amount is constant.

At time t2, although the mode was switched to the weak regeneration mode, the driver's intention remains deceleration. However, the motor rotation speed shows a substantially constant speed running, and the deceleration tendency as intended by the driver is not shown.

At time t3, the driver switches the regeneration mode to the constant speed mode. However, since the correction gain does not change from 0.5 here as well, the disturbance correction amount is constant.

At time t4, the correction gain is the same as at time t1 and the like, and the disturbance correction amount is small with respect to the gradient disturbance, so that the vehicle tends to accelerate, and it is not possible to travel at a constant speed contrary to the driver's intention.

On the other hand, the control result of the present embodiment will be described with reference to FIG.

From time t0 to time t1, the same behavior as in the reference example is shown. Since this control result is a control when the accelerator opening is fully closed, the value of the first correction gain is 1. Therefore, the value of the third correction gain obtained by multiplying the first correction gain and the second correction gain is set to 0.5, which is the same as the reference example.

At time t1, the driver switches the regeneration mode to the weak regeneration mode via the regeneration mode switching SW10, and the basic torque target value is increased accordingly. Further, since the regeneration mode is switched to the weak regeneration mode, the correction gain changes accordingly. In the present embodiment, the correction gain of 0.75 is set in consideration of the driver feeling in the weak regeneration mode. As a result, it can be seen that the disturbance correction amount is also changed because the disturbance torque estimated value is multiplied by 0.75 as the correction gain when the weak regeneration mode is selected.

At time t2, the vehicle is decelerated by the first torque target value obtained by adding the disturbance correction amount to the basic torque target value. Since this first torque target value is set in consideration of the change to the weak regeneration mode, it can be seen that the deceleration tendency is shown more than that of the reference example toward time t3.

At time t3, the driver switches the regeneration mode to the constant speed mode. In this embodiment, 1.0 is set as the correction gain in the constant speed mode. As a result, 1.0 is multiplied by the disturbance torque estimated value, so that it can be seen that the disturbance correction amount and the disturbance torque estimated value match.

At time t4, the correction gain is 1.0, and the disturbance correction amount coincides with the gradient disturbance, so that the driver can travel at a constant speed as intended.

As described above, by applying the control device of the electric vehicle according to the present embodiment to the vehicle, when the driver's intention is regenerative braking (regenerative mode setting value is strong regeneration or weak regeneration), the driver feeling is met. It is possible to realize deceleration. When the driver's intention is a constant speed (regeneration mode set value is a constant speed), the driver's intention can be achieved.

Further, since the disturbance correction amount can be changed stepwise according to the intention of the driver (see time t1 and t3), the motor torque can be smoothly switched. Therefore, since the sudden change in torque generated at the timing when the regeneration mode is switched is prevented, the vibration generated at the time of switching the mode can be suppressed (see time t1 and t3).

Next, the control result on the uphill road will be described.

17 and 18 are time charts when decelerating on an uphill road with the accelerator opening fully closed. FIG. 17 shows the control result by the reference example, and FIG. 18 shows the control result by the control device of the electric vehicle in this embodiment.

17 and 18 show the basic torque target value, the disturbance correction amount, the motor rotation speed ωm, and the vehicle front-rear acceleration in order from the top. Further, in both the reference example and the present embodiment, the driver selects the strong regeneration mode from time t0 to t1 and the weak regeneration mode after time t1 via the regeneration mode switching SW10.

First, FIG. 17, which is a control result of the reference example, will be described.

Since the strong regeneration mode is selected as the initial setting at time t0, 0.5 as the correction gain when the strong regeneration mode is selected with respect to the estimated disturbance torque as described above with reference to FIG. The disturbance correction amount is calculated by multiplying by. Then, over time t1, the vehicle is decelerated by the first torque target value obtained by adding the disturbance correction amount to the basic torque target value.

At time t1, the driver switches the regeneration mode to the weak regeneration mode via the regeneration mode switching SW10, and the basic torque target value is increased accordingly. However, since the correction gain does not change from 0.5, the disturbance correction amount is constant.

At time t2, the correction gain is the same as the value at time t1, so the disturbance correction amount is small with respect to the gradient disturbance, and the vehicle shows a deceleration tendency more than the driver intended, so that the stop control is started early.

At time t3, stop control is being executed.

At time t4, the motor rotation speed is 0, and the vehicle is stopped. In the reference example, the regenerative torque before the start of stop control becomes larger than the driver's intention, so the vehicle decelerates more than the driver's intention. As a result, the vehicle stops just before the driver's intended position.

On the other hand, the control result of the present embodiment will be described with reference to FIG.

From time t0 to time t1, the same behavior as in the reference example is shown. Since this control result is a control when the accelerator opening is fully closed, the value of the first correction gain is 1. Therefore, the value of the third correction gain obtained by multiplying the first correction gain and the second correction gain is set to 0.5, which is the same as the reference example.

At time t1, the driver switches the regenerative mode to the weak regenerative mode via the regenerative mode switching switch, and the basic torque target value is increased accordingly. Further, since the regeneration mode is switched to the weak regeneration mode, the correction gain changes accordingly, and the disturbance correction amount increases.

At time t2, the vehicle is decelerated by the first torque target value obtained by adding the disturbance correction amount to the basic torque target value. Since this first torque target value is set in consideration of the change to the weak regeneration mode, it shows a gradual deceleration tendency compared to the reference example, and it is possible to realize deceleration according to the driver's intention. There is. Therefore, the stop control has not been started even at the time t2.

At time t3, stop control is started. It can be seen that the stop control is performed at the timing intended by the driver, and sufficient deceleration is performed by the time t3, so that the way the vehicle front-rear acceleration rises at the start of the stop control is also gradual.

At time t4, the vehicle is stopped.

As described above, by applying the control device for the electric vehicle according to the present embodiment to the vehicle, it is possible to realize deceleration that is more suitable for the driver feeling than the reference example. In addition, on an uphill road, the disturbance torque estimated value and the disturbance correction amount according to the basic torque target value that reflects the driver's intention are set, so deceleration and stopping according to the driver's intention should be realized. Can be done.

As described above, according to the control device for the electric vehicle of one embodiment, the motor 4 for driving the vehicle, the operating means (accelerator pedal) for instructing acceleration / deceleration of the vehicle, and the strength of the regenerative braking force generated by the motor can be arbitrarily set. It is a control device that realizes a control method of an electric vehicle including a regenerative level setting means (regeneration mode switching SW10) that can be set. The control device calculates a basic torque target value (torque table target value) according to the operation amount (accelerator opening) of the operating means, estimates the running resistance acting on the motor 4, and sets the regenerative mode switching SW10. The correction gain (third correction gain) corresponding to the above is calculated, and the travel resistance correction torque (disturbance correction amount) is calculated based on the travel resistance and the third correction gain. Then, the first torque target value Tm1 ^* as the final torque target value is calculated from the basic torque target value and the disturbance correction amount, and the motor is controlled according to the final torque target value.

This makes it possible to control the regenerative braking force of the motor without giving a sense of discomfort to the driver even on a sloped road. Specifically, the following effects can be obtained by setting the third correction gain according to the setting status of the regenerative braking force (strong regeneration, weak regeneration, and constant speed) and calculating the disturbance correction amount. Can be done. That is, on an uphill road when the driver's intention is weak regeneration, the torque change amount from before the start of the stop control to after the start of the stop control can be reduced to smoothly stop on the uphill road. Further, on a downhill road when the driver's intention is a constant speed, the driver can travel at a constant speed as the driver intends without accelerating due to the influence of the gradient resistance.

Further, according to the control device of the electric vehicle of one embodiment, the smaller the intensity (strong regeneration, weak regeneration) set by the regeneration level setting means (regeneration mode switching SW10), the larger the correction gain (second correction gain). Set to a value. As a result, the smaller the regenerative braking force set by the driver, the closer the driver's intention is to driving at a constant speed from the braking side. Therefore, by increasing the correction gain according to this intention, the disturbance correction amount can be switched more smoothly. Can be done.

Further, according to the control device of the electric vehicle of one embodiment, when the strength set by the regeneration level setting means (regeneration mode switching SW10) is set to the strength that cancels the traveling resistance, the second correction gain is set to 1. Set to. As a result, the disturbance correction amount and the disturbance torque estimated value match, so that the vehicle can travel at a constant speed with the influence of the traveling resistance canceled.

Further, according to the amount control device, the electric motor of one embodiment corresponds to the operation amount (accelerator opening degree θ) of the operating means when the correction gain (third correction gain) is switched from another value to 1. The target motor rotation speed of the motor is set, the motor rotation speed ωm of the motor 4 is acquired, the deviation between the target motor rotation speed and the motor rotation speed is calculated as the motor rotation speed deviation, and a predetermined feedback gain is obtained for the motor rotation speed deviation. The value obtained by multiplying (gain K) is set as the basic torque target value. As a result, even if there is a vehicle modeling error such as when the vehicle model and the actual vehicle mass deviate from each other, the feedback control using the motor rotation speed ωm is executed to reach the target motor rotation speed. The tracking performance can be improved.

Further, according to the control device of the electric vehicle of one embodiment, the traveling resistance is a disturbance torque acting on the motor 4, and the disturbance torque is a positive torque on a flat road and a torque on a flat road on an uphill road. On the above positive torque and downhill road, the torque is estimated to be less than the torque on the flat road. This makes it possible to estimate the disturbance torque according to the running resistance.

Further, according to the control device for the electric vehicle of one embodiment, the stop control torque target value (second torque target value) for stopping the vehicle and maintaining the stopped state as the speed parameter decreases in proportion to the traveling speed of the vehicle. When the speed parameter becomes equal to or less than a predetermined value, the stop control torque target value (second torque target value) is set as the final torque target value. As a result, it is possible to consider the running resistance input to the motor and the regenerative braking force set by the driver, and to realize a smooth stop from deceleration and maintenance of the stop.

Further, according to the control device of the electric vehicle of one embodiment, the running resistance is the difference between the model Gp (s) of the transmission characteristic of the torque input to the vehicle and the rotation speed of the motor 4 and the denominator order and the molecular order. The motor rotation speed ωm is applied to a filter having a transmission characteristic of H (s) / Gp (s) composed of a transmission characteristic H (s) that is equal to or greater than the difference between the denominator order and the molecular order of the vehicle model Gp (s). Input to calculate the first motor torque estimated value, input the motor torque command value to the filter having the transmission characteristic H (s), calculate the second motor torque estimated value, and calculate the first motor torque estimated value. It is estimated by calculating the deviation between the second motor torque estimate and the second motor torque estimate. As a result, the running resistance (estimated value of disturbance torque) can be estimated based on the vehicle model, so that the running resistance acting on the vehicle can be estimated more accurately.

Further, according to the control device of the electric vehicle of one embodiment, the operating means is an accelerator pedal. Here, the operating means for instructing the vehicle to accelerate or decelerate may include a brake for instructing deceleration. However, in the present embodiment, by limiting to the accelerator pedal, the regenerative braking force of the motor 4 can be controlled without depressing the accelerator pedal and the brake pedal.

Further, according to the control device of the electric vehicle of one embodiment, the regeneration level setting means is a switch provided in the vicinity of the steering of the vehicle. As a result, the regenerative level can be set by the switch near the steering, so that the regenerative braking force of the motor 4 can be controlled without the need to operate the accelerator pedal and the brake pedal.

Although the embodiments of the present invention and the modifications thereof have been described above, the above-described embodiments and modifications show only a part of the application examples of the present invention, and the technical scope of the present invention is defined in the above-described embodiments. It is not intended to be limited to a specific configuration. Further, the above-described embodiment and its modifications can be combined as appropriate.

Further, 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 rotation speed of the motor 4 decreases and the second torque target value Tm2 as the motor torque command value Tm ^{* *} Has been described as converging to the disturbance torque estimated value Td. 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 parameters are reduced 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).

2 ... Motor controller (controller)
4 ... Electric motor (motor)
10 ... Regenerative level setting means (regenerative mode switching SW)
11 ... Accelerator pedal

Claims (10)

The motor that drives the vehicle and
An operating means for instructing acceleration / deceleration of the vehicle,
In a control method for an electric vehicle including a regenerative level setting means capable of arbitrarily setting the strength of the regenerative braking force generated by the motor.
A basic torque target value is calculated according to the operation amount of the operating means, and the basic torque target value is calculated.
Estimating the running resistance acting on the motor,
The correction gain according to the set value of the regeneration level setting means is calculated, and the correction gain is calculated.
The running resistance correction torque is calculated based on the running resistance and the correction gain.
The final torque target value is calculated from the basic torque target value and the running resistance correction torque.
The motor is controlled according to the final torque target value.
How to control an electric vehicle. In the control method for an electric vehicle according to claim 1,
The smaller the intensity set by the regenerative level setting means, the larger the correction gain is set.
How to control an electric vehicle. In the method for controlling an electric vehicle according to claim 1 or 2.
When the intensity set by the regeneration level setting means is set to a value that cancels the running resistance, the correction gain is set to 1.
How to control an electric vehicle. In the control method for an electric vehicle according to claim 3,
When the correction gain is switched from another value to 1, the target motor rotation speed of the motor according to the operation amount of the operating means is set.
The motor rotation speed of the motor is acquired, and the motor rotation speed is acquired.
The deviation between the target motor rotation speed and the motor rotation speed is calculated as the motor rotation speed deviation.
A value obtained by multiplying the motor rotation speed deviation by a predetermined feedback gain is set as the basic torque target value.
How to control an electric vehicle. The method for controlling an electric vehicle according to any one of claims 1 to 4.
The traveling resistance is a disturbance torque acting on the motor.
The disturbance torque is
Positive torque on flat roads,
On an uphill road, a positive torque higher than the torque on the flat road,
On a downhill road, the torque is estimated to be less than or equal to the torque on the flat road.
How to control an electric vehicle. The method for controlling an electric vehicle according to any one of claims 1 to 5.
A stop control torque target value that converges on the running resistance as the speed parameter decreases in proportion to the running speed of the vehicle is calculated.
When the speed parameter becomes a predetermined value or less, the stop control torque target value is set to the final torque target value, the vehicle is stopped by the final torque target value, and the stopped state is maintained.
How to control an electric vehicle. The method for controlling an electric vehicle according to any one of claims 1 to 6.
The running resistance is
Transmission in which the difference between the model Gp (s) of the transmission characteristics of the torque input to the vehicle and the rotational speed of the motor and the denominator order and the molecular order is greater than or equal to the difference between the denominator order and the molecular order of the model Gp (s). The motor rotation speed of the motor is input to a filter having a transmission characteristic of H (s) / Gp (s) composed of the characteristic H (s) to calculate a first motor torque estimation value.
The final torque target value is input to the filter having the transmission characteristic H (s) to calculate the second motor torque estimation value.
Estimated by calculating the deviation between the first motor torque estimate and the second motor torque estimate.
How to control an electric vehicle. The method for controlling an electric vehicle according to any one of claims 1 to 7.
The operating means is an accelerator pedal.
How to control an electric vehicle. The method for controlling an electric vehicle according to any one of claims 1 to 8.
The regeneration level setting means is a switch provided in the vicinity of the steering wheel of the vehicle.
How to control an electric vehicle. A control device for an electric vehicle that uses a motor as a traveling drive source and decelerates by the regenerative braking force of the motor.
An operating means for instructing acceleration / deceleration of the vehicle,
A regenerative level setting means capable of arbitrarily setting the strength of the regenerative braking force generated by the motor, and a regenerative level setting means.
A controller that controls the operation of the motor is provided.
The controller
A torque target value is calculated according to the operation amount of the operation means, and the torque target value is calculated.
Estimating the running resistance acting on the motor,
The correction gain according to the set value of the regeneration level setting means is calculated, and the correction gain is calculated.
The running resistance correction torque is calculated based on the running resistance and the correction gain.
The final torque target value is calculated from the torque target value and the running resistance correction torque.
The motor is controlled according to the final torque target value.
Control device for electric vehicles.

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