JP2021175279A - Control method for electric vehicle and control device for electric vehicle - Google Patents

Abstract

To provide a control method and a control device for electric vehicle that can perform accurate and sufficient braking control even during a travel on a sandy road.SOLUTION: A control method for an electric vehicle 100 includes: a driving torque target value setting step of setting a driving torque target value Tm based upon vehicle information on the electric vehicle 100; a final torque command value calculation step of correcting the driving torque target value Tm based upon a motor rotating speed ωm as a rotating speed of an electric motor 4 to calculate a final torque command value Tmf for suppressing resonance of a vehicle driving system; a travel resistance detection step of detecting travel resistance on a road surface where the electric vehicle 100 travels; and a correction quantity change step of changing a correction quantity for the driving torque target value based upon the travel resistance.SELECTED DRAWING: Figure 7

Description

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

Patent Document 1 describes torque input to a motor and motor rotation in order to prevent vibration generated by a vehicle drive system connected between the electric motor and drive wheels in an electric vehicle using an electric motor as a power source. A control method for an electric vehicle that controls a target torque of an electric motor using a transmission model with speed is disclosed.

More specifically, in the control method of the electric vehicle of Patent Document 1, first, the drive torque target value Tm is calculated from the accelerator opening degree, the vehicle speed, and the like. Then, the calculated drive torque target value Tm is passed through a vibration damping filter having a characteristic of reducing a frequency component equal to the torsional vibration of the vehicle drive system to obtain the first torque target value Tm1. On the other hand, the second torque target value Tm2 is calculated based on the deviation between the estimated value of the motor rotation speed and the actually measured value of the motor rotation speed. Then, the final torque command value Tmf is calculated by adding the first torque target value Tm1 and the second torque target value Tm2. After that, the current of the electric motor is controlled so that the torque of the electric motor matches the final torque command value Tmf.

That is, the method for controlling an electric vehicle in Patent Document 1 suppresses vibration based on resonance between the electric motor and the vehicle drive system from the electric motor to the drive wheels by controlling the torque of the electric motor. As a result, it produces a vibration damping effect that suppresses the rotational vibration of the electric vehicle that occurs when the accelerator is depressed from the stopped state or the decelerated state.

Japanese Unexamined Patent Publication No. 2003-09566

When traveling on a sandy road surface or a deep snow road surface, the electric vehicle may vibrate more than when traveling on a normal flat road surface. On sandy roads, the cause is that the driving wheels sink into the road surface.

Specifically, on a sandy road surface or the like, the running resistance increases due to the subduction characteristics of the drive wheels. In addition, due to the spring mass characteristics of the suspension and the subduction characteristics of the drive wheels, the electric vehicle has not only rotational vibration in the vehicle front-rear direction due to the resonance point peculiar to the vehicle drive system, but also sustains in the vehicle vertical direction. Vibration occurs. For this reason, when the accelerator is depressed from a stopped state or a decelerated state on a road surface having a large running resistance such as a sandy road surface, vertical vibration occurs in the vehicle, which gives the driver a sense of discomfort.

As described above, when traveling on a sandy road surface or the like, vibration larger than the vibration due to the characteristics of the vehicle drive system generated when traveling on a flat road surface may occur. However, in the control method described in Patent Document 1, vibration damping control is performed using uniquely determined vibration damping parameters in the sense that the running resistance of the road surface is not taken into consideration. Therefore, with the control method described in Patent Document 1, it is difficult to perform accurate and sufficient vibration damping control when traveling on a sandy road surface or the like having a large traveling resistance.

In view of the above circumstances, it is an object of the present invention to provide a control method and a control device for an electric vehicle capable of performing accurate and sufficient vibration damping control even when traveling on a sandy road surface or the like.

According to one aspect of the present invention, there is provided a method for controlling an electric vehicle using an electric motor as a power source. This electric vehicle control method sets a drive torque target value setting step for setting a drive torque target value based on the vehicle information of the electric vehicle, and a drive torque target value based on the motor rotation speed which is the rotation speed of the electric motor. Based on the final torque command value calculation step that calculates the final torque command value that suppresses the resonance of the vehicle drive system by correction, the running resistance detection step that detects the running resistance of the road surface on which the electric vehicle runs, and the running resistance. A correction amount change step for changing the correction amount of the drive torque target value Tm is included.

According to the present invention, accurate and sufficient vibration damping control can be performed even when traveling on a sandy road surface or the like.

FIG. 1 is a block diagram showing a main configuration of an electric vehicle. FIG. 2 is a flowchart illustrating the main processing of the control method of the electric vehicle. FIG. 3 is a diagram showing an example of an accelerator opening degree-torque table. FIG. 4 is an explanatory diagram showing a mechanical model of an electric vehicle. FIG. 5 is a block diagram of the disturbance torque estimation process. FIG. 6 is an explanatory diagram showing a mechanical model of the gradient resistance estimation value calculation step. FIG. 7 is a block diagram of vibration damping control processing. FIG. 8 is an explanatory diagram of the frequency band changing step. FIG. 9 is an explanatory diagram of the gain changing step. FIG. 10 is a time chart showing changes over time of various parameters of the comparative example. FIG. 11 is a time chart showing changes over time of various parameters of the present invention. FIG. 12 is a block diagram showing a configuration of an electric vehicle of a modified example.

As shown in FIG. 1, the electric vehicle 100 includes a battery 1, a motor controller 2, an inverter 3, an electric motor 4, a speed reducer 5, a rotation sensor 6, a current sensor 7, a drive shaft 8, and a drive wheel 9a and a drive wheel. 9b and the like are provided. The electric vehicle means a vehicle powered by an electric motor. A vehicle in which an electric motor can be used as part or all of the vehicle's drive or braking source is an electric vehicle. That is, the electric vehicle includes not only an electric vehicle but also a hybrid vehicle, a fuel cell vehicle, and the like. The electric vehicle 100 of the present embodiment is an electric vehicle powered by an electric motor 4.

The battery 1 is connected to the electric motor 4 via an inverter 3, and supplies driving power to the electric motor 4 by discharging the battery 1. Further, the battery 1 can be charged by receiving the supply of regenerative power from the electric motor 4.

The motor controller 2 is, for example, a computer composed of a central arithmetic unit (CPU), a read-only memory (ROM), a random access memory (RAM), an input / output interface (I / O interface), and the like. The motor controller 2 generates a control signal for directly or indirectly controlling the electric motor 4 based on the vehicle information of the electric vehicle 100. By controlling the electric motor 4, the motor controller 2 comprehensively controls the operation of the electric vehicle 100.

The vehicle information is information indicating an operating state or a control state of the entire electric vehicle 100 or each part constituting the electric vehicle 100, and is a so-called vehicle variable. Vehicle information can be obtained by detection, measurement, generation, calculation, estimation, or the like. For example, the acceleration in the front-rear direction of the electric vehicle 100 (hereinafter referred to as the vehicle front-rear acceleration) Ac [m / s ² ], the vehicle speed V [km / h], the accelerator opening degree θ [%], and the rotor phase α of the electric motor 4. [Rad], the currents iu, iv, iwa [A] of the electric motor 4, the DC voltage value Vdc [V] of the battery 1, and the like are vehicle information of the electric vehicle 100. The motor controller 2 controls the electric motor 4 using, for example, these vehicle information input as digital signals.

The control signal for controlling the electric motor 4 is, for example, a PWM signal (Pulse Width Modulation signal) for controlling the current of the electric motor 4. Further, the motor controller 2 generates a drive signal for the inverter 3 in response to the PWM signal. The drive signal of the inverter 3 is also a control signal for controlling the electric motor 4.

The inverter 3 includes, for example, two switching elements (for example, power semiconductor elements such as an IGBT (Insulated Gate Bipolar Transistor) and a MOS-FET (metal-oxide-semiconductor field-effect transistor)) corresponding to each phase. .. The inverter 3 converts the direct current supplied from the battery 1 into an alternating current by turning on / off the switching element according to the drive signal generated by the motor controller 2, and adjusts the current supplied to the electric motor 4. .. Further, the inverter 3 reversely converts the alternating current generated by the electric motor 4 by the regenerative braking force into a direct current, and adjusts the current supplied to the battery 1.

The electric motor 4 is, for example, a three-phase AC motor, and generates a driving force by an AC current supplied from the inverter 3. The driving force generated by the electric motor 4 is transmitted to the pair of left and right drive wheels 9a and drive wheels 9b via the speed reducer 5 and the drive shaft 8. Further, when the electric motor 4 is rotated by being rotated by the drive wheels 9a and the drive wheels 9b, the electric motor 4 generates a regenerative braking force and recovers the kinetic energy of the electric vehicle 100 as electric energy.

The speed reducer 5 is composed of, for example, a plurality of gears. The speed reducer 5 reduces the rotational speed of the electric motor 4 and transmits it to the drive shaft 8 to generate a drive torque or braking torque (hereinafter, simply referred to as torque) proportional to the reduction ratio.

The rotation sensor 6 detects the rotor phase α of the electric motor 4 and outputs the rotor phase α to the motor controller 2. The rotation sensor 6 is, for example, a resolver or an encoder.

The current sensor 7 detects the current flowing through the electric motor 4 and outputs it to the motor controller 2. In the present embodiment, the current sensor 7 detects the three-phase alternating currents iu, iv, and iwa of the electric motor 4, respectively. The current sensor 7 may be used to detect the current of any two phases, and the current of the remaining one phase may be obtained by calculation.

The vehicle front-rear acceleration Ac, which is one of the vehicle information, can be detected at an arbitrary timing by using an acceleration sensor or another controller (not shown). The accelerator opening degree θ can be detected by using an accelerator opening degree sensor (not shown), another controller, or the like. The same applies to other vehicle information such as the vehicle speed V and the DC voltage value Vdc of the battery 1, and these various vehicle information can be detected at an arbitrary timing by using a sensor (not shown) or another controller.

As shown in FIG. 2, the motor controller 2 has an input process (step S201), a torque target value calculation process (step S202), a disturbance torque estimation process (step S203), a vibration suppression control process (step S204), and a current target value. The calculation process (step S205) and the current control process (step S206) are executed in this order at predetermined calculation cycles.

The input process in step S201 is a process in which the motor controller 2 receives the input of vehicle information and, if necessary, calculates various parameters used in the processes after step S202. In the present embodiment, the motor controller 2 obtains the vehicle front-rear acceleration Ac, the accelerator opening θ, the rotor phase α, the currents iu, iv, iw of the electric motor 4, and the DC voltage value Vdc of the battery 1 from various sensors. get.

Further, the motor controller 2 uses a part or all of the vehicle information directly acquired to obtain the motor electric angular velocity ωe [rad / s], which is the electric angular velocity of the electric motor 4, and the mechanical angular velocity of the electric motor 4. The motor rotation speed ωm [rad / s], the unit-converted electric motor 4 motor rotation speed Nm [rpm], the angular velocities ωw [rad / s] of the drive wheels 9a and 9b, the vehicle speed V, and the like. calculate.

Specifically, the motor controller 2 calculates the motor electric angular velocity ωe by time-differentiating the rotor phase α. After that, the motor controller 2 calculates the motor rotation speed ωm by dividing the motor electric angular velocity ωe by the number of pole pairs of the electric motor 4. Further, the motor controller 2 calculates the motor rotation speed Nm by multiplying the motor rotation speed ωm by the unit conversion coefficient (60 / 2π).

Further, the motor controller 2 calculates the angular velocities ωw of the drive wheels 9a and 9b by dividing the motor rotation speed ωm or the motor rotation speed Nm by the gear ratio of the final gear of the reduction gear 5. Then, the motor controller 2 calculates the vehicle speed V by multiplying the angular velocity ωw by the load radii r [m] of the drive wheels 9a and 9b and multiplying this by the unit conversion coefficient (3600/1000).

The vehicle speed V may be directly acquired by communicating with another controller such as a meter or a brake controller instead of calculating as described above. When the wheel speed sensors are provided on the plurality of drive wheels 9a and 9b, the average value of the wheel speed sensors can be used as the vehicle speed V. In addition, the vehicle speed V is an estimated vehicle speed value calculated by using a value acquired from a sensor such as GPS (Global Positioning System), using a value selected from a wheel speed sensor or the like, or using a front-rear acceleration sensor or the like. (Refer to JP-A-2002-127881, etc.) may be used.

The torque target value setting process in step S202 is a process for setting the drive torque target value Tm, which is the target value of the drive torque. The motor controller 2 sets the drive torque target value Tm based on the accelerator opening degree θ and the motor rotation speed ωm by referring to the accelerator opening degree-torque table shown in FIG. 3, for example. That is, step S202 is a drive torque target value setting step for setting the drive torque target value Tm based on the vehicle information of the electric vehicle 100.

The disturbance torque estimation process in step S203 is a process for calculating the disturbance torque estimated value Td ^. The disturbance torque is an amount of increase or decrease in torque that has increased or decreased due to disturbance to the electric vehicle 100. The disturbance torque estimated value Td ^ is an estimated value indicating the presence or absence of the disturbance torque and its amount. The disturbance with respect to the electric vehicle 100 is an external factor that increases or decreases the traveling resistance of the electric vehicle 100. Specifically, the disturbance to the electric vehicle 100 includes air resistance, modeling error due to fluctuation of vehicle weight according to the number of occupants and load capacity, rolling resistance of drive wheels 9a and 9b, slope resistance of road surface, and drive wheel 9a. , 9b sinking into the road surface, etc. The motor controller 2 calculates the disturbance torque estimated value Td ^ by using the motor rotation speed ωm and the previous value of the final torque command value Tmf calculated in step S204. Details of the disturbance torque estimation process will be described later.

The vibration damping control process in step S204 is a process for calculating the final torque command value Tmf that suppresses the resonance of the vehicle drive system. The motor controller 2 uses the drive torque target value Tm and the motor rotation speed ωm to calculate the final torque command value Tmf without sacrificing the torque response of the drive shaft 8. The resonance of the vehicle drive system is typically rotational vibration (hereinafter referred to as front-rear vibration) of the electric vehicle 100 in the front-rear direction caused by torsional vibration of the drive shaft 8 or the like. In addition, the resonance of the vehicle drive system includes vertical vibration of the electric vehicle 100 (hereinafter referred to as vertical vibration) caused by the sinking of the drive wheels 9a and 9b into the road surface. The drive control of the electric vehicle 100 according to the final torque command value Tmf of the present embodiment suppresses both the front-rear vibration and the up-down vibration of the electric vehicle 100. The details of the vibration damping control process will be described later.

The current target value calculation process in step S205 calculates the d-axis current target value id ^{*, which is the target value of the d-axis current id of the electric motor 4, and the q-axis current target value iq *} , which is the target value of the q-axis current iq. It is a process. The motor controller 2 has a dq-axis current target value table (dq-axis current target value table) that associates the final torque command value Tmf, the motor rotation speed ωm, and the DC voltage value Vdc with the d-axis current target value id ^* and the q-axis current target value iq ^*. (Not shown) is held in advance. Therefore, by referring to this dq-axis current target value table, the motor controller 2 refers to the d-axis current target values id ^* and q-axis corresponding to the final torque command value Tmf, the motor rotation speed ωm, and the DC voltage value Vdc. Calculate the current target value iq ^*.

The current control process in step S206 is a process for generating torque for driving or braking the electric vehicle 100 by controlling the current of the electric motor 4. In the current control process, the motor controller 2 first calculates the d-axis current id and the q-axis current iq based on the currents iu, iv, iwa of the electric motor 4 and the rotor phase α. Next, the motor controller 2 has d-axis voltage command values vd and q based on the deviation between the d-axis current target values id * and q-axis current target values iq * and the d-axis current id and q-axis current iq. The shaft voltage command value vq is calculated. Further, the motor controller 2 calculates the three-phase voltage command values vu, vv, vw based on the d-axis voltage command value vd, the q-axis voltage command value vq, and the rotor phase α. Then, the motor controller 2 calculates the duty ratio tu, tv, tw [%] of the PWM signals input to each phase based on the three-phase voltage command values vu, vv, vw and the DC voltage value Vdc.

The motor controller 2 controls the electric motor 4 by opening and closing the switching element of the inverter 3 according to the PWM signal thus obtained. As a result, the motor controller 2 drives or brakes the electric vehicle 100 with a desired torque specified by the final torque command value Tmf.

<Disturbance torque estimation process>
The motor controller 2 uses the transmission characteristic Gp (s) from the drive torque target value Tm to the motor rotation speed ωm in the disturbance torque estimation process. The transmission characteristic Gp (s) is calculated using the equation of motion derived from the mechanical model of the electric vehicle 100 shown in FIG. Each symbol in the mechanical model and / or equation of motion of the electric vehicle 100 of FIG. 4 is as follows.

Jm: Electric motor inertia Jw: Drive wheel inertia M: Vehicle mass KD: Vehicle drive system torsional rigidity Kt: Factor related to friction between drive wheels and road surface N: Overall gear ratio r: Drive wheel load radius ωm: Motor Rotation speed Tm: Drive torque target value TD: Drive wheel torque F: Force applied to the vehicle V: Vehicle speed (vehicle speed)
ωw: Angular velocity of drive wheels

The following equation of motion can be derived from the mechanical model of the electric vehicle 100 shown in FIG. The symbol "*" in the equations (1) to (3) represents the time derivative.

When the transmission characteristic Gp (s) is obtained based on the above equations of motion (1) to (5), it can be expressed by the equation (6). Further, the coefficients a _{1 to} a ₄ and the coefficients b _{0 to} b ₃ in the equation (6) are represented by the equations (7) to (14).

Examining the poles and zeros of the transmission characteristic Gp (s) shown in the above equation (6), one pole and one zero show extremely close values. This means that α and β in the following equation (15) show extremely close values.

Therefore, by performing the pole-zero cancellation that approximates α = β in the equation (15), the transfer characteristic Gp (s) of the (secondary) / (tertiary) form is obtained as in the following equation (16). be able to.

Further, the natural vibration angular velocity ωp can be expressed by the following equation (17) by _{using the coefficient a 1} ′ and the coefficient a ₃ ′ used in the denominator of the equation (16). Further, the natural vibration angular velocity ωp can be converted into a resonance frequency (natural vibration frequency) fp by the following equation (18).

In the present embodiment, the motor controller 2 uses the transmission characteristic Gp (s) of the equation (16) in the disturbance torque estimation process, but instead of the transmission characteristic Gp (s) of the equation (16), the following equation ( The transmission characteristic Gp (s) represented by 19) may be used. The equivalent mass Mv used in the transmission characteristic Gp (s) of the equation (19) is obtained from the mass M of the vehicle, the inertia Jm of the electric motor 4, and the inertia Jw of the drive wheels 9a and 9b as shown in the equation (20). .. _{The coefficient K M} used in the transfer characteristic Gp (s) of the equation (19) is represented by the equation (21).

As shown in FIG. 5, the disturbance torque estimation process includes a first motor torque estimation value calculation step, a second motor torque estimation value calculation step, a torque estimation deviation calculation step, and a gradient resistance estimation value calculation step. Includes a gradient resistance subtraction step.

In the first motor torque estimation value calculation step, the first motor torque estimation value T1 ^ is calculated by filtering the motor rotation speed ωm using the first motor torque estimation filter 501. The first motor torque estimation filter 501 is configured by using the low-pass filter H1 (s) represented by the following equation (22) using the time constant τv and the transmission characteristic Gp (s), and H1 ( It has the property of s) / Gp (s).

In the second motor torque estimation value calculation step, the second motor torque estimation value T2 ^ is calculated by filtering the final torque command value Tmf using the second motor torque estimation filter 502. The second motor torque estimation filter 502 is, for example, the same low-pass filter H1 (s) that constitutes the first motor torque estimation filter 501.

In the torque estimation deviation calculation step, the torque estimation deviation Tδ ^ is calculated by subtracting the first motor torque estimation value T1 ^ from the second motor torque estimation value T2 ^ using the subtractor 503.

In the gradient resistance estimation value calculation step, the gradient resistance estimation value Tg ^ is calculated using the vehicle front-rear acceleration Ac and the coefficient Kg using the multiplier 504. Gradient resistance is the running resistance caused by the slope of the road surface. As shown in FIG. 6, by multiplying the slope ψ by the coefficient Kg expressed by the following equation (23), the slope resistance estimated value Tg ^ required for the electric vehicle 100 to balance with the slope can be calculated. .. The symbol "r" is the load radius of the drive wheels 9a and 9b, the symbol "M" is the mass of the vehicle, the symbol "g" is the gravitational acceleration, and the symbol "N" is the overall gear ratio.

In the gradient resistance subtraction step, the disturbance torque estimated value Td ^ is calculated by subtracting the gradient resistance estimated value Tg ^ from the torque estimated deviation Tδ ^ using the subtractor 505.

As can be seen from the above calculation method, the disturbance torque estimated value Td ^ is obtained by subtracting the gradient resistance estimated value Tg ^ from the torque estimated deviation Tδ ^ that comprehensively estimates the disturbance torque caused by any disturbance. The effect of is reduced or excluded. Therefore, although the disturbance factor differs depending on the operating conditions, the disturbance torque estimation process can collectively estimate other disturbance torques excluding the gradient resistance. The disturbance torque other than the gradient resistance includes an increase in running resistance (hereinafter referred to as running resistance on the road surface) that increases due to the subduction of the drive wheels 9a and 9b into the road surface. Further, among a plurality of disturbance factors, the slope of the road surface and the subduction of the drive wheels 9a and 9b into the road surface are factors that greatly change the traveling resistance. However, the disturbance torque estimate Td ^ reduces or excludes the contribution of gradient resistance. Therefore, when the driving wheels 9a and 9b such as a sandy road surface, a deep snow road surface, or a muddy road surface travel on a road surface (hereinafter referred to as a soft road surface) subducting into the road surface, the disturbance torque estimated value Td ^ is substantially the same as the road surface. It indicates that the road surface is soft, that the drive wheels 9a and 9b are subducted on the soft road surface, and that the running resistance of the road surface is increased due to the soft road surface. On the other hand, when the drive wheels 9a and 9b travel on a normal road surface (hereinafter referred to as a hard road surface) in which the drive wheels 9a and 9b hardly sink into the road surface, the disturbance torque estimated value Td ^ does not fluctuate significantly. This fact indicates that the road surface is substantially a hard road surface, that the drive wheels 9a and 9b do not sink, and that there is no increase in the running resistance of the road surface. That is, the global fluctuation of the disturbance torque estimated value Td ^ represents the fluctuation of the traveling resistance of the road surface. Therefore, the disturbance torque estimation process (step S203) functions as a travel resistance detection step for detecting the travel resistance of the road surface on which the electric vehicle 100 travels by calculating the disturbance torque estimation value Td ^.

<Damping control processing>
As shown in FIG. 7, the vibration damping control process corrects the drive torque target value Tm based on the motor rotation speed ωm to calculate the final torque command value Tmf that suppresses the resonance of the vehicle drive system. Includes value calculation steps. In the present embodiment, the final torque command value calculation step includes a first torque target value calculation step, a second torque target value calculation step, and an addition step.

In the first torque target value calculation step, the first torque target value Tm1 is calculated using the vibration damping filter 701. The vibration damping filter 701 is a feedforward compensator, and outputs a first torque target value Tm1 by filtering the drive torque target value Tm. The vibration damping filter 701 is configured by using the ideal transmission characteristic Gm (s) and the transmission characteristic Gp (s), and has a characteristic of Gm (s) / Gp (s). The ideal transmission characteristic Gm (s) is an ideal model of the transmission characteristic of the motor rotation speed ωm from the drive torque target value Tm. On the other hand, the transmission characteristic Gp (s) is, as described above, a model of a practical transmission characteristic in consideration of the torsional vibration of the vehicle drive system. Therefore, the first torque target value Tm1 is a torque target value that reduces the factors that cause torsional vibration of the vehicle drive system.

In the second torque target value calculation step, the second torque target value Tm2 is calculated using the disturbance suppression filter 702. The disturbance suppression filter 702 is a feedback compensator, and receives inputs of the previous value of the final torque command value Tmf, the motor rotation speed ωm, and the disturbance torque estimated value Td ^, and outputs the second torque target value Tm2.

More specifically, the second torque target value calculation step includes a motor rotation speed estimation value calculation step, a deviation calculation step, an estimation disturbance calculation step, and a gain multiplication step.

In the motor rotation speed estimation value calculation step, the motor rotation speed estimation value ωm ^ is calculated from the previous value of the final torque command value Tmf using the vehicle model 711 of the electric vehicle 100. The vehicle model 711 is a transmission characteristic Gp (s) which is a realistic model of the electric vehicle 100.

In the deviation calculation step, the deviation Δ between the motor rotation speed ωm and the motor rotation speed estimated value ωm ^ is calculated using the subtractor 712. In the present embodiment, the subtractor 712 calculates the deviation Δ by subtracting the motor rotation speed ωm from the motor rotation speed estimated value ωm ^.

In the estimated disturbance calculation step, the estimated disturbance d ^ is calculated by extracting the disturbance component which is a component of the predetermined frequency band from the deviation Δ using the disturbance estimation filter 713. The disturbance estimation filter 713 is configured by using the transmission characteristic H2 (s) and the transmission characteristic Gp (s), and has a characteristic of H2 (s) / Gp (s).

The transmission characteristic H2 (s) is set so that 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 transmission characteristic Gp (s). Further, the transmission characteristic H2 (s) can be configured by, for example, a bandpass filter. When the transmission characteristic H2 (s) is used as a bandpass filter, the disturbance suppression filter 702 serves as a feedback element that selectively reduces the resonance of the vehicle drive system generated in the electric vehicle 100.

As shown in FIG. 8A, in principle, the transmission characteristic H2 (s) has substantially the same damping characteristics on the low-pass side and the high-pass side, and the resonance frequency fp of the torsional vibration of the vehicle drive system is on the logarithmic axis ( Set so that it is close to the median value of the pass band on the log scale). In this case, the disturbance suppression filter 702 exerts the greatest vibration suppression effect on the resonance of the torsional vibration of the vehicle drive system.

The attenuation characteristic on the low-pass side refers to a mode of change in the passage characteristic in the vicinity of _{the cutoff frequency f LC} on the low frequency side of the transmission characteristic H2 (s). Further, the attenuation characteristic on the high-pass side refers to a mode of change in the passage characteristic in the vicinity of _{the cutoff frequency f HC} on the high frequency side of the transmission characteristic H2 (s). “Match” with respect to the attenuation characteristics on the low-pass side and the high-pass side means that the attenuation characteristics on the low-pass side and the attenuation characteristics on the high-pass side are symmetrical with respect to the median values of the cutoff frequency fLC and the cutoff frequency fHC on the logarithmic axis. It means that it is. Further, the “neighborhood” means that a fluctuation of a specific value can be tolerated to the extent that there is no substantial difference in the realistic driving of the electric vehicle 100.

When the transmission characteristic H2 (s) is composed of a first-order high-pass filter and a first-order low-pass filter, the transmission characteristic H2 (s) uses the time constant τ _H of the high-pass filter and the time constant τ _L of the low-pass filter. It can be configured by the following equation (24). Further, the time constants τ _H , τ _L and the cutoff frequencies f _HC , f _LC use the resonance frequency fp of the front-rear vibration caused by the torsional vibration of the vehicle drive system, the predetermined frequency fq, and the predetermined coefficient k. , It is represented by the following formulas (25) to (27). The resonance frequency fp of the front-rear vibration is a constant predetermined by the vehicle model of the electric vehicle 100 as described above. Further, the coefficient k is set so that the disturbance suppression filter 702 functions by an experiment, a simulation, or the like according to the specific electric vehicle 100.

Further, the transmission characteristic H2 (s) sets _{the frequency fq (see equation (28)) that determines the cutoff frequency f LC} of the low-pass filter as a variable that can be switched according to the disturbance torque estimated value Td ^. When the disturbance torque estimated value Td ^ is less than the predetermined value C0, fq = fp is set. _{In this case, the center frequencies of the cutoff frequencies f HC} and f _LC of the high-pass filter and the low-pass filter are the resonance frequency fp of the front-rear vibration caused by the torsional vibration of the vehicle drive system. On the other hand, when the disturbance torque estimated value Td ^ is equal to or higher than the predetermined value C0, the variable frequency fq is set to fq = by using the resonance frequency fp1 of the vertical vibration caused by the subduction of the drive wheels 9a and 9b into the road surface. Set to fp1. As a result, as shown in FIG. 8B, the cutoff frequency f _LC on the low frequency side of the transmission characteristic H2 (s) is switched to the low frequency side, and the pass band includes the resonance frequency fp1 of the vertical vibration. Become.

The resonance frequency fp1 of the vertical vibration determines what kind of soft road surface the electric vehicle 100 travels on, such as a sandy road surface, a deep snow road surface, or a muddy road surface, and / or a practical driving wheel 9a on these. It may vary depending on the degree of subduction of 9b. However, the resonance frequency fp1 of the vertical vibration is at least lower than the resonance frequency fp of the front-rear vibration regardless of the specific type of the soft road surface and the actual degree of subduction of the drive wheels 9a and 9b. .. Further, as compared with the gap between the resonance frequency fp of the front-rear vibration and the resonance frequency fp1 of the vertical vibration, the fluctuation of the resonance frequency fp1 of the vertical vibration is small depending on the type of the soft road surface and the degree of subduction of the drive wheels 9a and 9b. Therefore, the resonance frequency fp1 of the vertical vibration can be set in advance based on the vehicle model of the electric vehicle 100.

_{The predetermined value C0 used for switching the cutoff frequency f LC} on the low frequency side is a standard for determining whether or not the disturbance torque estimated value Td ^ includes a component due to vertical vibration in addition to a component due to front-back vibration. Further, when vertical vibration is generated due to the traveling resistance of the road surface, the increase in the disturbance torque estimated value Td ^ is remarkable. Therefore, the predetermined value C0 can be arbitrarily and preset with respect to the disturbance torque estimated value Td ^ within a range in which the presence or absence of vertical vibration can be determined. By setting the predetermined value C0 in this way, when the disturbance torque estimated value Td ^ is equal to or higher than the predetermined value C0, the motor controller 2 determines that the road surface on which the electric vehicle 100 travels is a soft road surface having high traveling resistance. I can judge. Then, the motor controller 2 changes the variable frequency fq to a low frequency in consideration of vertical vibration.

In the gain multiplication step, the second torque target value Tm2 is calculated by multiplying the estimated disturbance d ^ calculated as described above by the feedback gain Kfb using the multiplier 714. As shown in FIG. 9, the feedback gain Kfb is variable according to the disturbance torque estimated value Td ^. Further, the feedback gain Kfb is set large according to the disturbance torque estimated value Td ^. For example, the feedback gain Kfb is set so as to increase monotonically according to the disturbance torque estimated value Td ^.

In the addition step, the final torque command value Tmf is calculated by adding the first torque target value Tm1 and the second torque target value Tm2 using the adder 703. That is, in the final torque command value calculation step, the feedforward correction that corrects the drive torque target value Tm based on the deviation from the ideal transmission characteristic Gm (s) and the value of the drive torque target value Tm based on the estimated disturbance d ^ are set. The final torque command value Tmf is calculated by performing two correction processes, the feedback correction to be corrected and the correction process. Since the estimated disturbance d ^ is calculated based on the motor rotation speed ωm, it can be said that the final torque command value Tmf is calculated based on the motor rotation speed ωm by the feedback correction.

The motor controller 2 drives the electric vehicle 100 according to the final torque command value Tmf. However, when the electric vehicle 100 actually travels, a disturbance is applied to the electric vehicle 100, so that there is a discrepancy between the motor rotation speed ωm and the motor rotation speed estimated value ωm ^ of the electric vehicle 100 due to the disturbance. Therefore, since the deviation Δ is not always zero, the feedback correction using the disturbance suppression filter 702 exerts a vibration damping effect until the deviation Δ becomes substantially zero.

In addition to the vibration damping control process, the control method for the electric vehicle 100 of the present invention further includes a correction amount changing step. In the correction amount changing step, the correction amount of the drive torque target value Tm is changed based on the running resistance of the road surface. As described above, there are two types of correction of the drive torque target value Tm: feedforward correction using the vibration damping filter 701 and feedback correction using the disturbance suppression filter 702. The correction amount of the feedback correction using the disturbance suppression filter 702 is changed. Further, since the disturbance torque estimated value Td ^ represents the traveling resistance of the road surface, the correction amount is changed based on the traveling resistance of the road surface by using the disturbance torque estimated value Td ^ in the correction amount changing step.

The correction amount changing step can be composed of a gain changing step and / or a frequency band changing step. In the present embodiment, the correction amount changing step includes both a gain changing step and a frequency band changing step.

The gain change step changes the value of the feedback gain Kfb to be multiplied by the estimated disturbance d ^ based on the disturbance torque estimated value Td ^ representing the running resistance of the road surface. Further, in the gain change step, the larger the disturbance torque estimated value Td ^, the larger the value of the feedback gain Kfb is set.

In the frequency band change step, a predetermined frequency band which is a pass band of the disturbance estimation filter 713 is changed based on the disturbance torque estimated value Td ^ representing the traveling resistance of the road surface. Then, the predetermined frequency band is changed by changing the lower limit value of the predetermined frequency band, that is, the cutoff frequency f _LC of the disturbance estimation filter 713. Further, the change of the predetermined frequency band is to expand the predetermined frequency band by changing the _{cutoff frequency f LC to the low frequency side.}

As described above, one aspect of the control method of the electric vehicle 100 is a control method of the electric vehicle 100 using the electric motor 4 as a power source, and the drive torque target value Tm is set based on the vehicle information of the electric vehicle 100. By correcting the drive torque target value Tm based on the drive torque target value setting step to be set and the motor rotation speed ωm which is the rotation speed of the electric motor 4, the final torque command value Tmf that suppresses the resonance of the vehicle drive system is set. A final torque command value calculation step to be calculated, a running resistance detection step to detect the running resistance of the road surface on which the electric vehicle 100 is running, and a correction amount changing step to change the correction amount of the drive torque target value Tm based on the running resistance. ,including. Therefore, even when the traveling resistance changes due to the subduction of the drive wheels 9a and 9b into the soft road surface, both the frequency component of the resonance point of the front-rear vibration and the frequency component of the resonance point of the vertical vibration are driven torque target value Tm. The final torque command value Tmf reduced or removed from can be set. Therefore, even when the accelerator is depressed from a stopped state or a decelerated state on a soft road surface such as a sandy road surface, it is possible to obtain an accurate and sufficient damping effect for both front-back vibration and vertical vibration. As a result, the electric vehicle 100 can be smoothly accelerated even on a sandy road surface or the like.

For example, in the electric vehicle of the comparative example, the final torque command value Tmf that suppresses the torsional vibration of the vehicle drive system is calculated by feedback-correcting the drive torque target value Tm based on the motor rotation speed ωm. However, the electric vehicle of the comparative example does not perform the traveling resistance detection step and the correction amount changing step. In this case, as shown in FIG. 10 (A), when the electric vehicle of the comparative example is started by depressing a certain amount of the accelerator at the time t1 from the state of being stopped from the time t0 to the time t1, the accelerator is depressed. The drive torque target value Tm becomes a constant value accordingly. Further, when the drive wheels 9a and 9b start to rotate, they sink into the sandy road surface, so that the traveling resistance in the forward direction increases, and the disturbance torque estimated value Td ^ becomes a positive constant value. Further, the disturbance torque estimated value Td ^ is a value larger than that in the case of the hard road surface due to the increase in the traveling resistance of the road surface, but the electric vehicle of the comparative example does not detect this and performs constant control. On the other hand, in the electric vehicle of the comparative example, the drive torque target value Tm is corrected by feedback control based on the motor rotation speed ωm. Therefore, when the final torque command value Tmf starts to increase stepwise according to the depression of the accelerator, the vehicle A constant feedback correction that suppresses the front-back vibration caused by the torsional vibration of the drive system works, and then the final torque command value Tmf changes vibratingly.

As a result, as shown in FIG. 10 (B), the motor rotation speed Nm also changes oscillatingly, so that the subduction of the drive wheels also changes oscillatingly as shown in FIG. 10 (C). As a result, as shown in FIG. 10D, vertical vibration occurs in the electric vehicle of the comparative example due to the subduction of the drive wheels. Further, this vertical vibration is hardly attenuated by the vibration damping control process performed by the electric vehicle of the comparative example, and continues for a long time.

On the other hand, in the electric vehicle 100, in addition to the feedback correction control of the drive torque target value Tm based on the motor rotation speed ωm, a running resistance detection step and a correction amount change step are performed. When the electric vehicle 100 is started by depressing a certain amount of accelerator at time t1 from a state where the electric vehicle 100 is stopped from time t0 to time t1 on a sandy road surface, as shown in FIG. 11 (A), the accelerator is depressed. The drive torque target value Tm becomes a constant value accordingly, which is the same as that of the electric vehicle of the comparative example. Also, when the drive wheels 9a and 9b start to rotate, the drive wheels 9a and 9b sink into the sandy road surface, so that the running resistance in the forward direction increases, and the disturbance torque estimated value Td ^ becomes a positive constant value. It is the same as the electric vehicle of the example.

However, in the electric vehicle 100, the traveling resistance of the road surface is detected by the disturbance torque estimated value Td ^. Then, by comparing the disturbance torque estimated value Td ^ with the predetermined value C0, if it is determined that the vehicle is traveling on a soft road surface having a high running resistance, the feedback gain Kfb is changed according to the disturbance torque estimated value Td ^. .. Further, the predetermined frequency band of the disturbance estimation filter 713 is expanded according to the disturbance torque estimation value Td ^, and the resonance frequency fp1 of the vertical vibration is extracted in addition to the resonance frequency fp of the front-rear vibration to obtain the final torque command value Tmf. Be fed back.

As a result, the final torque command value Tmf changes oscillatingly from the time t1 when the accelerator depression is started to around the very initial time t2. However, the vibration of the final torque command value Tmf is attenuated at an early stage, and converges to a constant value from time t3 to time t5 and thereafter. As a result, as shown in FIG. 11B, the vibration at the motor rotation speed Nm is also suppressed, and as shown in FIG. 11C, the amount of subduction of the drive wheels 9a and 9b also converges. Therefore, in the electric vehicle 100, the front-rear vibration due to the torsional vibration of the vehicle drive system is suppressed as in the electric vehicle of the comparative example, and as shown in FIG. 11 (D), as compared with the electric vehicle of the comparative example, The electric vehicle 100 hardly generates vertical vibration due to the subduction of the drive wheels 9a and 9b. Further, the vertical vibration slightly generated in the electric vehicle 100 is also attenuated at an early stage. Further, in the electric vehicle 100, the amount of subduction of the drive wheels 9a and 9b is smaller than that of the electric vehicle of the comparative example. Further, in the electric vehicle 100, the amount of subduction of the drive wheels 9a and 9b stabilizes at an almost constant value at an early stage. Therefore, the electric vehicle 100 can minimize the increase in running resistance even on a sandy road surface, and can obtain a higher acceleration faster than the electric vehicle of the comparative example.

In addition to the above, one aspect of the control method of the electric vehicle 100 is a motor rotation speed estimated value ωm ^ which is an estimated value of the rotation speed of the electric motor 4 based on the transmission characteristic Gp (s) which is a model of the electric vehicle 100. The disturbance applied to the electric vehicle 100 based on the deviation Δ between the motor rotation speed estimation value calculation step for calculating the motor rotation speed, the motor rotation speed ωm which is the actual rotation speed of the electric motor 4, and the motor rotation speed estimation value ωm ^. In the final torque command value calculation step, which includes an estimated disturbance calculation step for calculating the estimated disturbance d ^, which is an estimated value of, the drive torque target value Tm is corrected based on the estimated disturbance d ^. This estimated disturbance d ^ includes not only the resonance frequency fp of the front-rear vibration of the vehicle drive system but also the resonance frequency fp1 of the vertical vibration when the vertical vibration occurs. Therefore, according to the above control method, a more specific and particularly effective control logic that can accurately and sufficiently suppress not only the front-rear vibration of the electric vehicle 100 but also the vertical vibration is realized.

Further, one aspect of the control method of the electric vehicle 100 has a gain multiplication step of multiplying the estimated disturbance d ^ by the feedback gain Kfb, and the correction amount changing step is a gain for changing the value of the feedback gain Kfb based on the traveling resistance. Includes change steps. As a result, it is easy to obtain a particularly accurate and sufficient damping effect on the front-rear vibration and the up-down vibration of the electric vehicle 100.

In particular, in one aspect of the control method of the electric vehicle 100, the value of the feedback gain Kfb is set larger as the traveling resistance is larger in the gain changing step. As a result, the electric vehicle 100 can exhibit sound vibration suppression performance according to the traveling resistance of the road surface. For example, the feedback gain Kfb, which is larger than that of the conventional electric vehicle, can be uniformly multiplied regardless of the disturbance torque estimated value Td ^. However, if the feedback gain Kfb is set large in the entire range regardless of the disturbance torque estimated value Td ^ or the like, sound vibration including high frequency noise in the audible range may occur depending on the vehicle speed V or the like, which may give the driver a sense of discomfort. Therefore, as described above, a traveling scene in which vertical vibration occurs and the traveling resistance is large is determined. Then, by switching not to use the high feedback gain Kfb for the soft road surface at least on the hard road surface, it is possible to obtain an accurate and sufficient vibration damping effect against vertical vibration while maintaining an appropriate sound vibration suppression performance.

In one aspect of the control method of the electric vehicle 100, in the estimated disturbance calculation step, the estimated disturbance d ^ is calculated by extracting the components of the predetermined frequency band from the motor rotation speed ωm, the motor rotation speed estimated value ωm ^, and the deviation Δ. The correction amount changing step includes a frequency band changing step of changing a predetermined frequency band based on the running resistance. As a result, when vertical vibration occurs, the estimated disturbance d ^ surely includes the component of the resonance frequency fp1 of the vertical vibration, so that it is particularly easy to obtain an accurate and sufficient damping effect on the vertical vibration.

Further, in one aspect of the control method of the electric vehicle 100, in the frequency band changing step, the lower limit value of the predetermined frequency band is changed based on the traveling resistance. Normally, the resonance frequency fp1 of the vertical vibration is lower than the resonance frequency fp of the front-back vibration, so that it is _{not the cutoff frequency f HC} on the high frequency side, which is the upper limit of the predetermined frequency band, but the lower limit. It is sufficient to adjust _{the cutoff frequency f LC} on the low frequency side. Therefore, if the lower limit value of the predetermined frequency band is changed, an accurate and sufficient upper limit vibration suppression effect can be obtained with a slight adjustment.

Further, one aspect of the control method of the electric vehicle 100 is to expand the predetermined frequency band by changing the lower limit value of the predetermined frequency band to the low frequency side based on the traveling resistance in the frequency band changing step. By changing the lower limit of the predetermined frequency band to the low frequency side and increasing the sensitivity (gain) on the low frequency side of the disturbance estimation filter 713 in this way, the resonance of vertical vibration to the estimated disturbance d ^ with the minimum necessary adjustment. The frequency fp1 can be included. As a result, it is possible to obtain a vibration damping effect of vertical vibration particularly accurately and sufficiently.

In one aspect of the control method of the electric vehicle 100, in the traveling resistance detection step, a first motor torque estimated value T1 ^ estimated using the motor rotation speed ωm and a final torque command value Tmf input to the electric vehicle 100 are used. Based on the second motor torque estimated value T2 ^ and the torque estimated deviation Tδ ^, which is the deviation of the second motor torque estimated value T2 ^, the disturbance torque estimated value Td ^ representing the running resistance is calculated. This makes it possible to accurately estimate the running resistance of sand, deep snow, mud, etc. Then, since the correction amount of the feedback correction of the drive torque target value Tm is changed according to the disturbance torque estimated value Td ^, a particularly accurate and sufficient effect of suppressing vertical vibration can be obtained.

Further, in one aspect of the control method of the electric vehicle 100, the traveling resistance detection step calculates the gradient resistance estimated value Tg ^ which calculates the gradient resistance estimated value Tg ^ based on the vehicle front-rear acceleration Ac which is the acceleration in the front-rear direction of the electric vehicle 100. Gradient resistance for calculating running resistance by subtracting the gradient resistance estimated value Tg ^ from the torque estimated deviation Tδ ^, which is the deviation between the step and the first motor torque estimated value T1 ^ and the second motor torque estimated value T2 ^. Includes a subtraction step and. That is, the gradient resistance estimated value Tg ^ is subtracted in the calculation of the disturbance torque estimated value Td ^ representing the running resistance. Thereby, the running resistance of the road surface is evaluated by reducing or eliminating the influence of the slope of the road surface. Therefore, since the correction amount of the feedback correction of the drive torque target value Tm is changed according to the disturbance torque estimated value Td ^ that reduces the influence of the gradient resistance, it is possible to obtain a particularly accurate and sufficient effect of suppressing vertical vibration. can.

The above-described embodiment is a control device for an electric vehicle 100 that uses an electric motor 4 as a power source, and has a drive torque target value setting unit that sets a drive torque target value Tm based on vehicle information of the electric vehicle 100, and an electric motor. The final torque command value calculation unit that calculates the final torque command value Tmf that suppresses the resonance of the vehicle drive system by correcting the drive torque target value Tm based on the motor rotation speed ωm, which is the rotation speed of the motor 4, and the electric motor It includes a control device for an electric vehicle including a traveling resistance detecting unit that detects the traveling resistance of the road surface on which the vehicle 100 travels, and a correction amount changing unit that changes the correction amount of the drive torque target value Tm based on the traveling resistance. The motor controller 2 functions as a drive torque target value setting unit, a running resistance detection unit, a final torque command value calculation unit, and a correction amount changing unit.

In the control method of the electric vehicle 100 of the above embodiment, some configurations are changed or omitted, or a new configuration is added within a range in which an accurate and sufficient vibration damping effect can be obtained on a sandy road surface or the like. You can. For example, in the above embodiment, the correction amount changing step includes both the gain changing step and the frequency band changing step, but the correction amount changing step is configured by only one of the gain changing step and the frequency band changing step. You may. This is because even when only one of the gain changing step and the frequency band changing step is performed, the effect of suppressing not only the front-rear vibration of the electric vehicle 100 but also the vertical vibration can be obtained on a soft road surface such as a sandy road surface. However, when both the gain changing step and the frequency band changing step are carried out as in the above embodiment, the electric vehicle 100 tends to obtain a particularly accurate and sufficient effect of suppressing vertical vibration.

In the above embodiment, in the frequency band changing step, the frequency fq defining the low frequency side cutoff frequency f _LC of the disturbance estimation filter 713 are switched at the resonance frequency fp1 of the vertical vibration and the resonance frequency fp of the longitudinal vibrations However, the frequency fq can be changed continuously or stepwise. For example, in the above embodiment, the resonance frequency fp1 of the vertical vibration is set to be substantially constant, but strictly speaking, the resonance frequency fp1 generated differs depending on the type of the road surface and the condition of the road surface even on a soft road surface. .. Further, depending on the type of road surface and the condition of the road surface, a plurality of vertical vibrations having different resonance frequencies may occur. Therefore, the frequency fq is not limited to the two values of the resonance frequency fp and the resonance frequency fp1 based on the type of the road surface and the condition of the road surface, and if the frequency fq is changed continuously or stepwise, the vertical vibration can be suppressed more accurately. There is. In acquiring such a road surface type and road surface condition, the motor controller 2 can use map information, position information, and / or weather information in combination with the disturbance torque estimated value Td ^ in the above embodiment.

Further, in the above embodiment, in the frequency band change step, the motor controller 2 changes the cutoff frequency f _LC on the low frequency side of the disturbance estimation filter 713, but changes the cutoff frequency f _{LC on the low frequency side. Alternatively, or in addition to changing the cutoff frequency f LC} on the low frequency side, the cutoff _{frequency f HC} on the high frequency side may be changed. In many cases, the resonance frequency fp1 of the vertical vibration is lower than the resonance frequency fp of the front-back vibration, but depending on the specific characteristics of the soft road surface, the vertical vibration having a higher frequency than the resonance frequency fp of the front-back vibration may occur. It may occur. Further, depending on the specific characteristics of the soft road surface, vertical vibration having a frequency lower than the resonance frequency fp of the front-back vibration and vertical vibration having a frequency higher than the resonance frequency fp of the front-back vibration may occur. In such a case, if the motor controller 2 changes the cutoff frequency f _HC on the high frequency side in the frequency band changing step, the vertical vibration at a high frequency can be accurately and sufficiently suppressed. In order for the motor controller 2 to _{be able to change the cutoff frequency f HC} on the high frequency side, the resonance frequency fp is set in the equation (26) in the same manner as the switching _{of the cutoff frequency f LC} on the low frequency side in the above embodiment. The part may be used as a variable, the resonance frequency of the generated high-frequency vertical vibration may be taken into consideration, and this may be switched according to the value of the disturbance torque estimated value Td ^.

Further, in the above embodiment, when vertical vibration occurs in the frequency band changing step, the cutoff frequency f _LC is switched to the lower frequency side. _{This is because the cutoff frequency f LC} is larger than the resonance frequency fp1 of the vertical vibration when fq = fp. However, in the frequency band change step, it is arbitrary whether the motor controller 2 switches the cutoff frequency fLC to the low frequency side or the high frequency side. That is, in the frequency band change step, the cutoff frequency f _LC can be switched to the high frequency side. For example, when fq = fp, if a _{disturbance estimation filter having a cutoff frequency f LC} smaller than the resonance frequency fp1 of the vertical vibration is used, the vertical vibration does not occur, contrary to the above embodiment. By switching the cutoff frequency f _LC to the high frequency side, the resonance frequency fp1 of the vertical vibration can be removed. Such control accurately and sufficiently suppresses vertical vibration, and secures sound vibration suppression performance according to the traveling resistance of the road surface. The same applies to the case where _{the cutoff frequency f HC} on the high frequency side is made variable.

The control method of the electric vehicle 100 of the above embodiment detects the running resistance of the road surface by calculating the disturbance torque estimated value Td ^. However, if the running resistance of the road surface can be appropriately grasped, the disturbance torque estimation in the above embodiment is performed. The running resistance of the road surface may be detected by a method other than the calculation of the value Td ^. The same applies to the estimation of the gradient resistance and the like, and the estimation of the gradient resistance and the like may be estimated by a method other than the method of the above embodiment.

In the above embodiment, a two-wheel drive (2WD) electric vehicle 100 for driving a pair of left and right drive wheels 9a and 9b using one electric motor 4 has been described, but the present invention has four-wheel drive. It is also suitable for the (4WD) electric vehicle 1200. As shown in FIG. 12, the 4WD electric vehicle 1200 includes, for example, a front drive system 1201f, a rear drive system 1201r, and a battery 1210 and a motor controller 1220 common to the front drive system 1201f and the rear drive system 1201r. ..

The front drive system 1201f includes a front inverter 3f, a front drive motor 4f, a front reduction gear 5f, a front rotation sensor 6f, a front current sensor 7f, a front drive shaft 8f, and a pair of front drive wheels 9af and 9bf. The rear drive system 1201r includes a rear inverter 3r, a rear drive motor 4r, a rear reducer 5r, a rear rotation sensor 6r, a rear current sensor 7r, a rear drive shaft 8r, and a pair of rear drive wheels 9ar and 9br.

The front inverter 3f and the rear inverter 3r correspond to the inverter 3 of the electric vehicle 100. The front drive motor 4f and the rear drive motor 4r correspond to the electric motor 4 of the electric vehicle 100. The front speed reducer 5f and the rear speed reducer 5r correspond to the speed reducer 5 of the electric vehicle 100. The front rotation sensor 6f and the rear rotation sensor 6r correspond to the rotation sensor 6 of the electric vehicle 100, and input the front rotor phase αf and the rear rotor phase αr to the motor controller 1220, respectively. The front current sensor 7f and the rear current sensor 7r correspond to the current sensor 7 of the electric vehicle 100, and input the front currents iuf, ivf, and iwf and the rear currents iur, ivr, and iwr to the motor controller 1220, respectively. The front drive shaft 8f and the rear drive shaft 8r correspond to the drive shaft 8 of the electric vehicle 100. The front drive wheels 9af, 9bf and the rear drive wheels 9ar, 9br correspond to the drive wheels 9a, 9b of the electric vehicle 100.

The battery 1210 is one or more batteries corresponding to the battery 1 of the electric vehicle 100. The battery 1210 supplies electric power to the front drive motor 4f and the rear drive motor 4r via the front inverter 3f and the rear inverter 3r, respectively, or receives an input of regenerative electric power.

The motor controller 1220 corresponds to the motor controller 2 of the electric vehicle 100, and controls the front drive system 1201f and the rear drive system 1201r in the same manner as the motor controller 2 of the electric vehicle 100. However, the motor controller 1220 may detect the traveling resistance on the road surface in either the front drive system 1201f or the rear drive system 1201r in the same manner as the electric vehicle 100. Further, the motor controller 1220 changes the correction amount of the drive torque target value Tm of either the front drive system 1201f or the rear drive system 1201r based on the detected running resistance of the road surface, thereby causing vertical vibration on a sandy road surface or the like. Can be suppressed. Further, when the correction amount of the drive torque target value Tm based on the traveling resistance of the road surface is changed in both the front drive system 1201f and the rear drive system 1201r, the motor controller 1220 is independent of the front drive system 1201f and the rear drive system 1201r. The correction amount of the drive torque target value Tm can be changed. Of course, the motor controller 1220 may change the correction amount of the drive torque target value Tm in common with the front drive system 1201f and the rear drive system 1201r.

1: Battery 2: Motor controller 3: Inverter 3f: Front inverter 3r: Rear inverter 4: Electric motor 4f: Front drive motor 4r: Rear drive motor 5: Reducer 5f: Front reducer 5r: Rear reducer 6: Rotation sensor 6f: Front rotation sensor 6r: Rear rotation sensor 7: Current sensor 7f: Front current sensor 7r: Rear current sensor 8: Drive shaft 8f: Front drive shaft 8r: Rear drive shaft 9a: Drive wheel 9af: Front drive wheel 9ar: Rear Drive wheel 9b: Drive wheel 9bf: Front drive wheel 9br: Rear drive wheel 100: Electric vehicle 501: First motor torque estimation filter 502: Second motor torque estimation filter 503: Subtractor 504: Multiplier 505: Subtractor 701: Vibration suppression filter 702: Disturbance suppression filter 703: Adder 711: Vehicle model 712: Subtractor 713: Disturbance estimation filter 714: Multiplier 1200: Motor vehicle 1201f: Front drive system 1201r: Rear drive system 1210: Battery 1220: Motor controller

Claims (10)

It is a control method for an electric vehicle that uses an electric motor as a power source.
A drive torque target value setting step for setting a drive torque target value based on the vehicle information of the electric vehicle, and a drive torque target value setting step.
A final torque command value calculation step for calculating a final torque command value that suppresses resonance of the vehicle drive system by correcting the drive torque target value based on the motor rotation speed, which is the rotation speed of the electric motor.
A traveling resistance detection step for detecting the traveling resistance of the road surface on which the electric vehicle travels, and
A correction amount change step for changing the correction amount of the drive torque target value based on the running resistance, and
How to control an electric vehicle, including. The method for controlling an electric vehicle according to claim 1.
Based on the model of the electric vehicle, a motor rotation speed estimation value calculation step for calculating a motor rotation speed estimation value which is an estimation value of the rotation speed of the electric motor, and a motor rotation speed estimation value calculation step.
Estimated disturbance calculation step for calculating an estimated disturbance which is an estimated value of a disturbance applied to the electric vehicle based on a deviation between the motor rotation speed which is the actual rotation speed of the electric motor and the motor rotation speed estimated value. When,
Including
In the final torque command value calculation step, the drive torque target value is corrected based on the estimated disturbance.
How to control an electric vehicle. The method for controlling an electric vehicle according to claim 2.
It has a gain multiplication step that multiplies the estimated disturbance by the gain.
The correction amount changing step includes a gain changing step of changing the value of the gain based on the running resistance.
How to control an electric vehicle. The method for controlling an electric vehicle according to claim 3.
In the gain changing step, the larger the running resistance, the larger the value of the gain is set.
How to control an electric vehicle. The method for controlling an electric vehicle according to any one of claims 2 to 4.
In the estimated disturbance calculation step, the estimated disturbance is calculated by extracting a disturbance component in a predetermined frequency band from the motor rotation speed, the motor rotation speed estimated value, and the deviation.
The correction amount changing step includes a frequency band changing step of changing the predetermined frequency band based on the traveling resistance.
How to control an electric vehicle. The method for controlling an electric vehicle according to claim 5.
In the frequency band change step, the lower limit value of the predetermined frequency band is changed based on the running resistance.
How to control an electric vehicle. The method for controlling an electric vehicle according to claim 6.
In the frequency band changing step, the predetermined frequency band is expanded by changing the lower limit value of the predetermined frequency band to the low frequency side based on the traveling resistance.
How to control an electric vehicle. The method for controlling an electric vehicle according to any one of claims 2 to 7.
In the traveling resistance detection step, a first motor torque estimated value estimated using the motor rotation speed and a second motor torque estimated value estimated using the final torque command value input to the electric vehicle. Calculate the running resistance based on the deviation,
How to control an electric vehicle. The method for controlling an electric vehicle according to claim 8.
The running resistance detection step
A gradient resistance estimated value calculation step for calculating a gradient resistance estimated value based on the acceleration in the front-rear direction of the electric vehicle, and a gradient resistance estimated value calculation step.
A gradient resistance subtraction step of subtracting the gradient resistance estimated value from the deviation between the first motor torque estimated value and the second motor torque estimated value to calculate the running resistance, and a gradient resistance subtraction step.
How to control an electric vehicle, including. A control device for an electric vehicle powered by an electric motor.
A drive torque target value setting unit that sets a drive torque target value based on the vehicle information of the electric vehicle, and a drive torque target value setting unit.
A final torque command value calculation unit that calculates a final torque command value that suppresses resonance of the vehicle drive system by correcting the drive torque target value based on the motor rotation speed that is the rotation speed of the electric motor.
A traveling resistance detection unit that detects the traveling resistance of the road surface on which the electric vehicle travels,
A correction amount changing unit that changes the correction amount of the drive torque target value based on the running resistance,
A control device for an electric vehicle.

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