Control Method for Electric Vehicle and Control Device for Electric Vehicle

Abstract

This invention provides a control method for an electric motor vehicle comprising an electric motor as a drive source. In this control method, a torque target value, which is a target value of torque to be outputted by the electric motor, is set on the basis of vehicle information, and a basic feedback compensation value is calculated on the basis of a parameter representing the rotation state of the electric motor and a vehicle model of the electric motor vehicle. A first feedback compensation value is calculated by multiplying the basic feedback compensation value by a first gain. A specific frequency component determined in advance is extracted from the basic feedback compensation value, and a second feedback compensation value is calculated by multiplying the specific frequency component by a second gain. A torque command value is calculated by correcting the torque target value according to the first feedback compensation value and the second feedback compensation value. The electric motor is then driven on the basis of the torque command value.

Description

Technical Field

[0001] The present invention relates to a control method and a control device for an electric vehicle including an electric motor as a drive source.

Background Art

[0002] JP2003-009566A discloses vibration control for an electric vehicle using a feedforward compensator and a feedback compensator. The feedforward compensator in this document functions as a vibration control filter having a characteristic of reducing a frequency component equal to the torsional vibration of the wheel drive system. Further, the feedback compensator is configured to perform vibration control based on the deviation between the estimated value and the measured value of the motor rotation speed.

Summary of the Invention

[0003] As described above, the conventional vibration control is control for reducing the vibration of the vehicle mainly caused by the torsional vibration of the wheel drive system from the motor to the wheels. On the other hand, in a driving scene where the driving resistance is large, such as on sandy ground, or in a driving scene where the driving load is large, vertical vibration may occur in the vehicle body. That is, during high-load driving, vibration may occur in the vehicle body due to factors other than the torsional vibration of the wheel drive system, and sufficient vibration control effect may not be obtained by the conventional vibration control.

[0004] An object of the present invention is to provide a control method and a control device for an electric vehicle that can suppress vibration of the vehicle body not only caused by torsional vibration of the wheel drive system but also caused by factors other than torsional vibration of the wheel drive system.

[0005] One aspect of the present invention is a control method for an electric vehicle including an electric motor as a drive source. In this control method, based on vehicle information, a torque target value, which is a target value of the torque to be output to the electric motor, is set, and based on a parameter representing the rotational state of the electric motor and a vehicle model of the electric vehicle, including at least the frequency band of torsional vibration of the vehicle drive systemThe basic feedback compensation value is calculated. Also, the first feedback compensation value is calculated by multiplying the basic feedback compensation value by a first gain. On the other hand, a specific frequency component determined in advance is extracted from the basic feedback compensation value, and the second feedback compensation value is calculated by multiplying this specific frequency component by a second gain. Then, the torque command value is calculated by correcting the torque target value with the first feedback compensation value and the second feedback compensation value. Thereafter, the electric motor is driven based on the torque command value.

Brief Description of the Drawings

[0006]

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Mode for Carrying Out the Invention

[0007] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0008] FIG. 1 is a block diagram showing the main configuration of the electric vehicle 100. 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 drive wheels 9a and 9b. The electric vehicle refers to a vehicle that uses an electric motor as a drive source or a braking source. A vehicle that can use an electric motor as part or all of the drive source or braking source of the vehicle is an electric vehicle. That is, electric vehicles include electric vehicles, hybrid vehicles, fuel cell vehicles, etc. in addition to electric vehicles. The electric vehicle 100 of the present embodiment is an electric vehicle that uses the electric motor 4 as a drive source.

[0009] The battery 1 is connected to the electric motor 4 via the inverter 3, and supplies drive power to the electric motor 4 by discharging. Further, the battery 1 can be charged by receiving regenerative power from the electric motor 4.

[0010] The motor controller 2 is a computer 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 generates a control signal for directly or indirectly controlling the electric motor 4 based on the vehicle information of the electric vehicle 100. The motor controller 2 is programmed to generate a control signal for the electric motor 4 at a predetermined control cycle.

[0011] The vehicle information is information indicating the operating state or control state of the entire electric vehicle 100 or each part constituting the electric vehicle 100, and is a so-called vehicle variable. The vehicle information can be obtained by detection, measurement, generation, calculation, estimation, or the like. For example, the longitudinal acceleration (hereinafter referred to as longitudinal acceleration) A L [m / s- 2 , vehicle speed V [km / h], accelerator opening θ [%], rotor phase α [rad] of the electric motor 4, current i u , i v , i w [A], and the DC voltage value V dc [V] (not shown) of the battery 1 are the vehicle information of the electric vehicle 100. The motor controller 2 controls the electric motor 4 using this vehicle information input as a digital signal, for example.

[0012] 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 according to the PWM signal. The drive signal for the inverter 3 is also a control signal for controlling the electric motor 4.

[0013] The inverter 3 includes, for example, two switching elements (e.g., power semiconductor elements such as IGBT (Insulated Gate Bipolar Transistor) and MOS-FET (metal-oxide-semiconductor field-effect transistor)) corresponding to each phase. The inverter 3 turns on / off the switching elements according to the drive signal generated by the motor controller 2, converts the direct current supplied from the battery 1 into an alternating current, and adjusts the current supplied to the electric motor 4. Further, the inverter 3 inversely converts the alternating current generated by the electric motor 4 due to the regenerative braking force into a direct current, and adjusts the current supplied to the battery 1.

[0014] The electric motor 4 is, for example, a three-phase alternating current motor, and generates a driving force by the alternating current supplied from the inverter 3. The driving force generated by the electric motor 4 is transmitted to a pair of left and right drive wheels 9a and 9b via the speed reducer 5 and the drive shaft 8. Further, when the electric motor 4 is rotated by being driven by the drive wheels 9a and 9b, the electric motor 4 generates a regenerative braking force, and recovers the kinetic energy of the electric vehicle 100 as electrical energy.

[0015] 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, thereby generating a driving torque or a braking torque (hereinafter simply referred to as torque) proportional to the reduction ratio.

[0016] The rotation sensor 6 detects the rotor phase α of the electric motor 4 and outputs it to the motor controller 2. The rotation sensor 6 is, for example, a resolver or an encoder.

[0017] 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 is the three-phase alternating current i u , i v , i wEach is detected. Note that, using the current sensor 7, the current of any two phases may be detected, and the current of the remaining one phase may be obtained by calculation.

[0018] Note that the longitudinal acceleration A, which is one of the vehicle information L can be detected at any timing by using an acceleration sensor (not shown) or other controllers, etc. The accelerator opening θ can be detected by using an accelerator opening sensor (not shown) or other controllers, etc. Also, the vehicle speed V and the DC voltage value V of the battery 1 dc and other vehicle information are the same. These various vehicle information can be detected at any timing by using sensors (not shown) or other controllers.

[0019] FIG. 2 is a flowchart showing the control mode of the electric vehicle 100. As shown in FIG. 2, the motor controller 2 executes input processing, torque target value setting processing, disturbance torque estimation processing, vibration suppression control processing, current target value calculation processing, and current control processing in this order for each predetermined control cycle.

[0020] The input processing in step S201 is a process in which the motor controller 2 receives the input of vehicle information and calculates various parameters used in the processes after step S202 as necessary.

[0021] In the present embodiment, the motor controller 2 obtains the longitudinal acceleration A L , the accelerator opening θ, the rotor phase α, the current i of the electric motor 4 u , i v , i w , and the DC voltage value V of the battery 1 dc from various sensors. Also, the motor controller 2 uses some or all of these vehicle information directly obtained to calculate the motor electrical angular velocity ω e [rad / s], which is the electrical angular velocity of the electric motor 4, the rotational speed ω m [rad / s], which is the mechanical angular velocity of the electric motor 4, the rotation speed N of the electric motor 4 after unit conversion m [rpm], and the angular velocity ω of the drive wheels 9a, 9b w[rad / s], and calculates the vehicle speed V, etc.

[0022] Specifically, the motor controller 2 calculates the motor electrical angular velocity ω by time-differentiating the rotor phase α. e Thereafter, the motor controller 2 calculates the rotational speed ω by dividing the motor electrical angular velocity ω by the number of pole pairs of the electric motor 4. e Furthermore, the motor controller 2 calculates the rotational speed N by multiplying the rotational speed ω by the unit conversion coefficient (60 / 2π). m Moreover, the motor controller 2 calculates the angular velocity ω of the drive wheels 9a, 9b by dividing the rotational speed ω or the rotational speed N by the gear ratio of the final gear of the speed reducer 5. m Then, the motor controller 2 multiplies the angular velocity ω by the load radius r [m] of the drive wheels 9a, 9b and multiplies this by the unit conversion coefficient (3600 / 1000) to calculate the vehicle speed V. m

[0023] In addition, the motor controller 2 m or the rotational speed N m to calculate the angular velocity ω of the drive wheels 9a, 9b by dividing by the gear ratio of the final gear of the speed reducer 5. w And the motor controller 2 multiplies the angular velocity ω by the load radius r [m] of the drive wheels 9a, 9b and multiplies this by the unit conversion coefficient (3600 / 1000) to calculate the vehicle speed V. w

[0024] Note that the vehicle speed V may be directly obtained by communicating with other controllers such as a meter or a brake controller instead of being calculated as described above. Also, when wheel speed sensors are provided for each of the plurality of drive wheels 9a, 9b, the average value of each wheel speed sensor value can be used as the vehicle speed V. In addition, the vehicle speed V may use a value obtained from a sensor such as GPS (Global Positioning System), a value selected from a wheel speed sensor, etc., or a vehicle speed estimated value calculated using a front-rear acceleration sensor or the like (see, for example, Japanese Patent Application Laid-Open No. 2002-127881).

[0025] The torque target value setting process in step S202 is the drive torque target value T, which is the target value related to the drive torque of the electric vehicle 100. m ​​is a process of setting. The motor controller 2 refers to, for example, the accelerator opening-torque table shown in FIG. 3, and based on the accelerator opening θ and the rotational speed N m sets the drive torque target value T m . That is, the motor controller 2 functions as a drive torque target value setting unit, or a torque target value setting unit.

[0026] The disturbance torque estimation process in step S203 is a process of calculating an estimated value of the torque (hereinafter referred to as disturbance torque) generated due to the disturbance acting on the electric vehicle 100. The disturbance acting on the electric vehicle 100 is an external factor that increases or decreases the running resistance of the electric vehicle 100. Specifically, the disturbances acting on the electric vehicle 100 include air resistance, modeling errors due to fluctuations in vehicle weight according to the number of passengers and the load, rolling resistance of the drive wheels 9a, 9b, gradient resistance of the road surface, and sinking of the drive wheels 9a, 9b into the road surface. The motor controller 2 uses the rotational speed ω m and the previous value of the final torque command value T mf calculated in step S204 to calculate the estimated value of the disturbance torque T d ^. The details of the disturbance torque estimation process will be described later.

[0027] The vibration suppression control process in step S204 is a process of calculating the final torque command value T mf for suppressing the vibration of the wheel drive system. The motor controller 2 uses the drive torque target value T m and the rotational speed ω m to calculate the final torque command value T mf without sacrificing the torque response of the drive shaft 8. The vibration of the wheel drive system is typically the rotational vibration (hereinafter referred to as longitudinal vibration) of the electric vehicle 100 in the longitudinal direction caused by torsional vibration of the drive shaft 8 or the like. In addition, the vibration of the wheel drive system includes the vertical vibration (hereinafter referred to as vertical vibration) of the electric vehicle 100 caused by the sinking of the drive wheels 9a, 9b into the road surface. The final torque command value T mfThe drive control of the electric vehicle 100 according to the present invention suppresses both the longitudinal vibration and the vertical vibration of the electric vehicle 100. Details of the vibration suppression control process will be described later.

[0028] The current target value calculation process in step S205 is a process of calculating the target value of the d-axis current i d of the d-axis current target value i d * and the target value of the q-axis current i q of the q-axis current target value i q * (both not shown). The motor controller 2 preliminarily holds a dq-axis current target value table (not shown) that associates the final torque command value T mf , the rotational speed ω m , and the DC voltage value V dc with the d-axis current target value i d * and the q-axis current target value i q * . Therefore, the motor controller 2 refers to this dq-axis current target value table to obtain the d-axis current target value i mf corresponding to the final torque command value T m , the rotational speed ω dc , and the DC voltage value V d * and the q-axis current target value i q * .

[0029] The current control process in step S206 is a process of generating the 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 i u , i v , i w of the electric motor 4 and the d-axis current i d and the q-axis current i q based on the rotor phase α. Next, the motor controller 2 calculates the difference between the d-axis current target value i d * and the q-axis current target value i q * and the d-axis current i d and the q-axis current iq and, based on the deviation, the d-axis voltage command value v d and the q-axis voltage command value v q are calculated. Further, the motor controller 2 uses the d-axis voltage command value v d and the q-axis voltage command value v q , and based on the rotor phase α, calculates the three-phase voltage command values v u , v v , v w . Then, the motor controller 2 calculates the duty ratios t u , t v , t w of the PWM signals input to each phase, based on the three-phase voltage command values v dc and the DC voltage value V u , t v , t w [%].

[0030] The motor controller 2 controls the electric motor 4 by opening and closing the switching elements of the inverter 3 according to the PWM signals thus obtained. As a result, the motor controller 2 drives or brakes the electric vehicle 100 with the desired torque specified by the final torque command value T mf . That is, the motor controller 2 and / or the inverter 3 function as a drive control unit that drives the electric motor 4 based on the final torque command value T mf .

[0031] <Disturbance torque estimation process> In the disturbance torque estimation process, the motor controller 2 uses the transfer characteristic Gp(s) from the drive torque target value T m to the rotational speed ω m . The transfer characteristic Gp(s) is a vehicle model of the electric vehicle 100 in which the torsional vibration of the wheel drive system is considered. The transfer characteristic Gp(s) is calculated using the equation of motion derived from the mechanical model of the electric vehicle 100 shown in FIG. 4. Each symbol in the mechanical model and / or the equation of motion of the electric vehicle 100 in FIG. 4 is as follows.

[0032] J m : Inertia of the electric motor Jw : Inertia of the driving wheel M: Mass of the vehicle KD: Torsional stiffness of the wheel drive system K t : Coefficient related to the friction between the driving wheel and the road surface N: Overall gear ratio r: Load radius of the driving wheel ω m : Rotational speed of the motor T m : Target value of the driving torque TD: Torque of the driving wheel F: Force applied to the vehicle V: Speed of the vehicle (vehicle speed) ω w : Angular velocity of the driving wheel

[0033] From the dynamic model of the electric vehicle 100 shown in FIG. 4, the following equations of motion (1) to (5) can be derived. Note that the symbol “*” in equations (1) to (3) represents time differentiation.

[0034]

Equation

[0035] Based on the above equations of motion (1) to (5), when the transfer characteristic Gp(s) is obtained, it can be expressed by equation (6). Also, the coefficients a 1 ~a 4 and the coefficients b 0 ~b 3 are represented by equations (7) to (14).

[0036]

Equation

[0037] When examining the poles and zeros of the transfer 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.

[0038] [Number]

[0039] Therefore, by performing pole-zero cancellation that approximates α = β in Equation (15), a transfer characteristic Gp(s) of the (second order) / (third order) form can be obtained as shown in the following Equation (16).

[0040] [Number]

[0041] Also, using the coefficient a 1 ′ and the coefficient a 3 ′, the natural vibration angular velocity ωp can be expressed by the following Equation (17). Furthermore, the natural vibration angular velocity ω p can be converted to the resonance frequency (natural vibration frequency) f p by the following Equation (18).

[0042] [Number]

[0043] In this embodiment, the motor controller 2 uses the transfer characteristic Gp(s) of Equation (16) in the disturbance torque estimation process, but instead of the transfer characteristic Gp(s) of Equation (16), a transfer characteristic Gp(s) represented by the following Equation (19) may be used. The equivalent mass M v used in the transfer characteristic Gp(s) of Equation (19) is obtained from the mass M of the vehicle, the inertia J m of the electric motor 4, and the inertia J w of the drive wheels 9a, 9b as shown in Equation (20). Also, the coefficient K M used in the transfer characteristic Gp(s) of Equation (19) is represented by Equation (21).

[0044] [Number]

[0045] FIG. 5 is a block diagram of the disturbance torque estimation process. As shown in FIG. 5, the motor controller 2 functions as a first motor torque estimator 501, a second motor torque estimator 502, a subtraction unit 503, a gradient resistance estimator 504, and a subtraction unit 505 to execute the disturbance torque estimation process.

[0046] The first motor torque estimator 501 calculates a first motor torque estimated value T1^. The first motor torque estimated value T1^ is a motor torque estimated based on the rotational speed ω. m In the present embodiment, the first motor torque estimator 501 calculates the first motor torque estimated value T1^ by filtering the rotational speed ω. m More specifically, the first motor torque estimator 501 is composed of a filter having a characteristic represented by H1(s) / Gp(s) using a low-pass filter H(s) and an inverse characteristic 1 / Gp(s) of the transfer characteristic Gp(s). The low-pass filter H(s) is represented by the following formula (22) using the time constant τ. 1 (s) 1 (s) v using the time constant τ

[0047]

Equation

[0048] The second motor torque estimator 502 calculates a second motor torque estimated value T2^. The second motor torque estimated value T2^ is a motor torque estimated based on the final torque command value T. mf In the present embodiment, the first motor torque estimator 501 calculates the second motor torque estimated value T2^ by filtering the final torque command value T. mf More specifically, the second motor torque estimator 502 is composed of a low-pass filter H(s). 1 (s)

[0049] The subtraction unit 503 calculates the deviation between the first motor torque estimated value T1^ and the second motor torque estimated value T2^ (hereinafter referred to as the torque estimation deviation ΔT^). In the present embodiment, the subtraction unit 503 calculates the torque estimation deviation ΔT^ by subtracting the first motor torque estimated value T1^ from the second motor torque estimated value T2^.

[0050] The gradient resistance estimation unit 504 calculates a gradient resistance estimated value T L ^ based on the longitudinal and lateral acceleration A g ^. The gradient resistance is the running resistance caused by the gradient of the road surface, and the gradient resistance estimated value T g ^ is its estimated value. In the present embodiment, the gradient resistance estimation unit 504 calculates the gradient resistance estimated value Tg^ by multiplying the longitudinal and lateral acceleration A L by a coefficient K g .

[0051] FIG. 6 is an explanatory diagram of the gradient resistance estimation process performed by the gradient resistance estimation unit 504. The force F applied to the electric vehicle 100, the gravitational force Mg acting on the electric vehicle 100, and the gradient ψ of the road surface are in the relationship shown in FIG. 6. Therefore, for the gradient ψ, the coefficient K g is represented by the following formula (23). By multiplying this coefficient K g by the longitudinal and lateral acceleration A L , the gradient resistance estimated value T g ^ for the electric vehicle 100 to balance on the road surface with the gradient ψ is calculated.

[0052]

Equation

[0053] The subtraction unit 505 calculates the disturbance torque estimated value T g ^ by subtracting the gradient resistance estimated value T d ^ from the torque estimation deviation ΔT^.

[0054] As described above, the disturbance torque estimated value T d ^ is obtained by subtracting the gradient resistance estimated value T g from the torque estimation deviation ΔT^ that comprehensively includes the disturbance torque caused by all disturbances.is calculated by subtracting ^. Therefore, the estimated disturbance torque T d ^ has the influence of gradient resistance reduced or excluded.

[0055] Among multiple disturbance factors, gradient resistance and the sinking of drive wheels 9a, 9b into the road surface are factors that particularly greatly vary the running resistance. However, the estimated disturbance torque T d ^ has the contribution of gradient resistance reduced or excluded as described above. Therefore, when driving on a road surface (hereinafter referred to as a soft road surface) such as a sandy road surface, a deep snow road surface, or a muddy road surface where drive wheels 9a, 9b sink into the road surface, the estimated disturbance torque T d ^ accurately represents the increase in running resistance due to the road surface being a soft road surface. On the other hand, when driving on a normal road surface (hereinafter referred to as a hard road surface) where drive wheels 9a, 9b hardly sink into the road surface, there is no significant variation in the estimated disturbance torque T d ^. That is, the estimated disturbance torque T d ^ represents the variation in the running resistance of the road surface.

[0056] <Vibration damping control process> FIG. 7 is a block diagram of the vibration damping control process. As shown in FIG. 7, the motor controller 2 functions as a feedforward compensator 701, a feedback compensator 702, and a final torque command value calculation unit 703 for the vibration damping control process.

[0057] The feedforward compensator 701 calculates a first torque target value T m based on the drive torque target value T m1 . In the present embodiment, the feedforward compensator 701 is a vibration damping filter, and calculates the first torque target value T m by filtering the drive torque target value T m1 . The feedforward compensator 701 is constituted by, for example, an ideal transfer characteristic Gm(s) and an inverse characteristic 1 / Gp(s) of a transfer characteristic Gp(s), and has a transfer characteristic of Gm(s) / Gp(s). This feedforward compensator 701 acts as a vibration damping filter that suppresses torsional vibration of the wheel drive system. Note that the ideal transfer characteristic Gm(s) is the drive torque target value Tm from the rotational speed ω m to the ideal transfer characteristic, and is the transfer characteristic with the attenuation coefficient (not shown) of the actual transfer characteristic Gp(s) being set to "1".

[0058] The feedback compensator 702 calculates the second torque target value T m based on the rotational speed ω m2 .

[0059] The final torque command value calculation unit 703 feeds back the second torque target value T m1 output by the feedback compensator 702 to the first torque target value T m2 output by the feedforward compensator 701 to calculate the final torque command value T mf . That is, the final torque command value calculation unit 703 corrects the first torque target value T m1 by the second torque target value T m2 to calculate the final torque command value T mf . In the present embodiment, the final torque command value calculation unit 703 is, for example, a subtraction unit, and subtracts the second torque target value T m1 from the first torque target value T m2 to calculate the final torque command value T mf . Note that the feedback of the second torque target value T m1 with respect to the first torque target value T m2 is synonymous with the feedback of the second torque target value T m with respect to the drive torque target value T m2 . Therefore, it can be said that the final torque command value calculation unit 703 feeds back the second torque target value T m to the drive torque target value T m2 .

[0060] The electric motor 4 is driven according to the final torque command value T mf . Also, when driving the electric motor 4 according to the final torque command value T mf , an external disturbance d may act. In FIG. 7, the electric vehicle 100 is represented by the transfer characteristic Gp′(s).

[0061] The feedback compensator 702 is configured as follows.

[0062] That is, the feedback compensator 702 includes a disturbance estimation filter 710, a first feedback compensation value calculation unit 711, a second feedback compensation value calculation unit 712, a third feedback compensation value calculation unit 713, a frequency setting unit 714, a second torque target value calculation unit 715, and a gain setting unit 716.

[0063] The disturbance estimation filter 710 is composed of a rotational speed estimator 721, a subtractor 722, and a disturbance estimator 723.

[0064] The rotational speed estimator 721 calculates an estimated value of the rotational speed ω mf ^, which is the estimated rotational speed ω m ^, based on the final torque command value T. More specifically, the rotational speed estimator 721 is a filter of the transfer characteristic Gp(s) that is the vehicle model of the electric vehicle 100. That is, the rotational speed estimator 721 calculates the estimated rotational speed ω m ^ by filtering the final torque command value T with the transfer characteristic Gp(s). mf m m ^.

[0065] The subtractor 722 calculates the deviation Δω m between the measured value of the rotational speed ω m and the estimated rotational speed ω m ^. In this embodiment, the subtractor 722 calculates the deviation Δω m ^ by subtracting the rotational speed ω- m (which is the measured value) from the estimated rotational speed ω m ^.

[0066] The disturbance estimator 723 calculates an estimated disturbance d^, which is an estimated value of the disturbance d acting on the electric vehicle 100, based on the deviation Δω m . The disturbance estimator 723 is composed of, for example, a band-pass filter H 2 (s) and the inverse characteristic 1 / Gp(s) of the transfer characteristic Gp(s), and H2 It is a filter having characteristics represented by (s) / Gp(s). Band-pass filter H 2 (s) is set to transmit the frequency band of the torsional vibration of the wheel drive system and the frequency components of the natural vibration of the electric vehicle 100 caused by the disturbance d. Also, the band-pass filter H 2 (s) is set so that the difference between the denominator degree and the numerator degree is equal to or greater than the difference between the denominator degree and the numerator degree of the transfer characteristic Gp(s). The disturbance estimator 723 is configured using the band-pass filter H 2 (s) having the above characteristics, so that the feedback compensator 702 functions as a feedback element for suppressing the torsional vibration of the wheel drive system and the vibration caused by the disturbance d. Therefore, the estimated disturbance d^ calculated by the disturbance estimator 723 is a basic feedback compensation value (hereinafter sometimes referred to as a basic feedback compensation value) in the feedback compensator 702. For this reason, the disturbance estimator 723 functions as a basic feedback compensation value calculation unit.

[0067] Note that, for example, when the band-pass filter H 2 (s) is composed of a first-order high-pass filter and a first-order low-pass filter, the band-pass filter H 2 (s) can be expressed by the following formula (24). Also, the time constant τ of the high-pass filter used in formula (24) H and the cut-off frequency f HC , as well as the time constant τ of the low-pass filter L and the cut-off frequency f LC are represented by the following formulas (25) to (28) using the resonance frequency f of the torsional vibration of the wheel drive system p and a predetermined coefficient k determined in advance.

[0068]

Equation

[0069] The first feedback compensation value calculation unit 711 calculates a feedback compensation value C1 based on the estimated disturbance d^ which is the basic feedback compensation value. The feedback compensation value C1 is a feedback compensation value for compensating the torsional vibration of the wheel drive system. In this embodiment, the first feedback compensation value calculation unit 711 multiplies the estimated disturbance d^ by a gain K fb1 by the multiplication unit 731 to calculate the feedback compensation value C1. The gain K fb1 is determined in advance by adaptation based on experiments or simulations, etc.

[0070] The second feedback compensation value calculation unit 712 calculates a feedback compensation value C2 based on the estimated disturbance d^ which is the basic feedback compensation value. The feedback compensation value C2 is a feedback compensation value for compensating the vertical vibration caused by the sinking of the tire when driving on a soft road surface such as sand.

[0071] In this embodiment, the second feedback compensation value calculation unit 712 is composed of a specific frequency component extractor 732 and a multiplication unit 733.

[0072] The specific frequency component extractor 732 is a filter that extracts the frequency component of the vertical vibration occurring on a soft road surface such as sand from the estimated disturbance d^. The specific frequency here is a specific frequency or a specific frequency band extracted by the specific frequency component extractor 732. Also, the specific frequency component is the component of the specific frequency extracted from the estimated disturbance d^ by the specific frequency component extractor 732. The specific frequency component extractor 732 is composed of, for example, a band-pass filter H 3 (s). Note that the frequency component of the vertical vibration occurring on a soft road surface such as sand is the natural vibration frequency component of the electric vehicle 100 and is known by experiments or simulations, etc. Therefore, the band-pass filter H 3 (s) is set to transmit at least the frequency component of the vertical vibration occurring on the soft road surface.

[0073] Figure 8 shows the band-pass filter H 3It is a graph showing the characteristics of (s). The horizontal axis of FIG. 8 is on a logarithmic scale. For example, the frequency of the vertical vibration (hereinafter referred to as the sandy ground vertical vibration frequency) f that occurs when the electric vehicle 100 travels on sandy ground sand is determined according to, for example, the suspension characteristics of the tires and the vehicle body of the electric vehicle 100 and the sinking characteristics of the tires into the sandy ground. Therefore, the sandy ground vertical vibration frequency f sand is known by experiments or simulations. For this reason, the band-pass filter H 3 (s) is set as shown in, for example, the following formula (29) so as to transmit the component of the sandy ground vertical vibration frequency f sand . Also, the time constant τ sand is represented by the following formula (30).

[0074]

Equation

[0075] In FIG. 8, the band-pass filter H 3 (s) is set so as to transmit the component of the sandy ground vertical vibration frequency f sand almost pinpoint. However, not limited to this, the band-pass filter H 3 (s) may be set so as to transmit the sandy ground vertical vibration frequency f sand and frequencies in its vicinity. That is, in FIG. 8, the band-pass filter H 3 (s) may be set so that its gain is, for example, a trapezoidal graph centered on the sandy ground vertical vibration frequency f sand .

[0076] Regarding the setting of the band-pass filter H 3 (s) when considering the vertical vibration occurring on soft road surfaces other than sandy ground, it is the same as the case of considering the vertical vibration occurring on the sandy ground described above. Also, when considering multiple types of soft road surfaces, the band-pass filter H 3 (s) can be set to transmit the frequencies of the vertical vibrations occurring on each soft road surface respectively. Also, the band-pass filter H 3(s) may be set to transmit a frequency band including the frequencies of the vertical vibrations generated on each soft road surface.

[0077] The multiplication unit 733 (see FIG. 7) multiplies a predetermined gain K by the specific frequency component extracted by the specific frequency component extractor 732. fb2 As a result, the feedback compensation value C2 is calculated. The gain K fb2 is variable, and the value of the gain K fb2 is adjusted by the gain setting unit 716.

[0078] The third feedback compensation value calculation unit 713 calculates a feedback compensation value C3 based on the estimated disturbance d^ which is the basic feedback compensation value. The feedback compensation value C3 is a feedback compensation value for compensating for the vibration generated in the electric vehicle 100 due to torque ripple (cogging) when going uphill.

[0079] In the present embodiment, the third feedback compensation value calculation unit 713 is composed of a specific frequency component extractor 734 and a multiplication unit 735.

[0080] The specific frequency component extractor 734 is a filter that extracts the frequency components of the natural vibration of the electric vehicle 100 generated in a driving scene where high torque is required, such as an uphill road, from the estimated disturbance d^. The specific frequency here is a specific frequency or a specific frequency band extracted by the specific frequency component extractor 734. Also, the specific frequency component is a component of the specific frequency extracted from the estimated disturbance d^ by the specific frequency component extractor 734. The specific frequency component extractor 734 is composed of, for example, a band-pass filter H 4 (s). The band-pass filter H 4 (s) is set as follows.

[0081] First, FIG. 9 is a graph showing the frequency of torque ripple (hereinafter referred to as torque ripple frequency) F tr generated when going uphill. As shown in FIG. 9, the torque ripple frequency F tr is the rotational speed ωm is proportional to. Also, the torque ripple frequency F tr varies depending on the order with respect to the electrical angle of the electric motor 4. Here, the torque ripple of the X-th electrical angle is shown by the solid line, and the torque ripple of the Y-th electrical angle (X < Y) is shown by the dashed-dotted line. For example, the rotational speed ω m is at a certain rotational speed ω 1 , in which case the frequency of the X-th torque ripple is "f x ", and the Y-th torque ripple frequency is "f y ".

[0082] Fig. 10 is a graph showing the characteristics of the band-pass filter H 4 (s). The horizontal axis of Fig. 10 is on a logarithmic scale. For example, the torque ripple frequencies f x , f y generated when the electric vehicle 100 climbs a slope are known through experiments or simulations, etc. Therefore, the band-pass filter H 4 (s) is set, for example, as shown in the following formula (31) so as to transmit each component of the X-th torque ripple frequency f x , and the Y-th torque ripple frequency f y . Also, the time constant τ X related to the X-th torque ripple is represented by the following formula (32), and the time constant τ Y related to the Y-th torque ripple is represented by the following formula (33).

[0083]

Equation

[0084] Furthermore, as described above, since the torque ripple frequencies f x , f y vary depending on the rotational speed ω m , the torque ripple frequencies f 4 (s) that determine the characteristics of the band-pass filter H x , f y are variable. That is, the characteristics of the band-pass filter H 4 (s) depend on the rotational speed ω mIt is appropriately adjusted according to the situation. Band-pass filter H 4 (s) is adjusted by the frequency setting unit 714.

[0085] The frequency setting unit 714 is based on the rotational speed ω m to change the torque ripple frequencies f 4 (s) that make up the band-pass filter H x , f y . Specifically, the frequency setting unit 714 increases the torque ripple frequencies f m as the rotational speed ω x , f y increases, and adjusts each torque ripple frequency f x , f y accordingly. As a result, the time constants τ X , τ Y are adjusted, and as a result, the characteristics of the band-pass filter H4(s) change according to the rotational speed ω m .

[0086] In FIG. 10, the band-pass filter H 4 (s) is set to transmit the torque ripple frequency components of each order almost pinpoint. However, it is not limited to this, and the band-pass filter H 4 (s) may be set to transmit the torque ripple frequencies of each order and the frequencies in the vicinity thereof. That is, in FIG. 10, the band-pass filter H 4 (s) may be set, for example, to be a combination of a trapezoidal graph centered on the X-order torque ripple frequency f x and a trapezoidal graph centered on the Y-order torque ripple frequency f y .

[0087] Here, the band-pass filter H 4 (s) is shown when considering the X-order torque ripple and the Y-order torque ripple schematically, but the band-pass filter H 4 (s) can be configured to consider only the X-order or Y-shaped torque ripple. Also, the band-pass filter H 4(s) can be configured to consider torque ripples of orders other than the X-th and / or Y-th order.

[0088] The multiplier 735 (see Fig. 7) multiplies a predetermined gain K to the specific frequency component extracted by the specific frequency component extractor 734. fb3 As a result, the feedback compensation value C3 is calculated. The gain K fb3 is variable, and the value of the gain K fb3 is adjusted by the gain setting unit 716.

[0089] The second torque target value calculation unit 715 calculates the second torque target value T m2 based on the feedback compensation values C1, C2, and C3. In the present embodiment, the second torque target value calculation unit 715 is configured by, for example, adding units 715a and 715b. The adding unit 715a adds the feedback compensation value C2 output by the second feedback compensation value calculation unit 712 and the feedback compensation value C3 output by the third feedback compensation value calculation unit 713. The adding unit 715b further adds the feedback compensation value C1 output by the first feedback compensation value calculation unit 711 to the output of the adding unit 715a to calculate the second torque target value T m2 . That is, the second torque target value calculation unit 715 calculates the second torque target value T m2 by summing up the feedback compensation values C1, C2, and C3.

[0090] The gain setting unit 716 adjusts the gain K fb2 of the second feedback compensation value calculation unit 712 and the gain K fb3 of the third feedback compensation value calculation unit 713 according to the running load. That is, when driving on a soft road surface such as sand or an uphill road, or when high torque driving is required, the gain setting unit 716 adjusts the gains K fb2 , K fb3 according to the running resistance. In the present embodiment, the gain setting unit 716 adjusts the gains K based on the estimated disturbance torque T d ^.fb2 , K fb3 is adjusted.

[0091] Figure 11 shows (A) the gain K fb2 and (B) the gain K fb3 in a graph showing a setting example.

[0092] As shown in Figure 11(A), the gain K fb2 of the second feedback compensation value calculation unit 712 is set to increase according to the estimated disturbance torque T d ^ when the absolute value of the estimated disturbance torque T d ^ is equal to or greater than a predetermined threshold Th1. That is, the gain setting unit 716 determines whether the vehicle is traveling on a soft road surface with a large running resistance based on the estimated disturbance torque T d ^. And when the estimated disturbance torque T d ^ is less than the threshold Th1 and it is determined that the running resistance is small and the vehicle is not traveling on a soft road surface such as sandy ground, the gain setting unit 716 sets the gain K fb2 of the second feedback compensation value calculation unit 712 to zero. Thereby, when traveling on a hard road surface, the second feedback compensation value calculation unit 712 is substantially invalidated, and overcompensation by the feedback compensation value C2 is prevented.

[0093] On the other hand, when the estimated disturbance torque T d ^ is equal to or greater than the threshold Th1 and it is determined that the vehicle is traveling on a soft road surface such as sandy ground with a large running resistance, the gain setting unit 716 adjusts the gain K fb2 to be proportional to the estimated disturbance torque T d ^, for example. That is, the greater the torque output by the electric motor 4, the greater the gain K fb2 is set. Thereby, an appropriate feedback compensation value C2 is calculated according to the amount of sinking (softness of the soft road surface) of the drive wheels 9a, 9b on the soft road surface.

[0094] As shown in Figure 11(B), the gain K fb3 of the third feedback compensation value calculation unit 713 is the estimated disturbance torque T dWhen the absolute value of ^ is equal to or greater than a predetermined threshold Th2, the estimated disturbance torque T d ^ is set to increase accordingly. That is, the gain setting unit 716 determines whether the vehicle is traveling on an uphill road where the running resistance is large and high torque is required based on the estimated disturbance torque T d ^. When the estimated disturbance torque T d ^ is less than the threshold Th2 and it is determined that the running resistance is small and the vehicle is not traveling on an uphill road, the gain setting unit 716 sets the gain K fb3 of the third feedback compensation value calculation unit 713 to zero. As a result, when traveling on a flat road or a downhill road, the third feedback compensation value calculation unit 713 is substantially invalidated, and overcompensation by the feedback compensation value C3 is prevented.

[0095] On the other hand, when the estimated disturbance torque T d ^ is equal to or greater than the threshold Th2 and it is determined that the vehicle is in a driving scenario where the running resistance is large and high torque is required, the gain setting unit 716 adjusts the gain K fb3 to be proportional to, for example, the estimated disturbance torque T d ^. That is, the greater the torque output by the electric motor 4, the greater the gain K fb3 is set. As a result, an appropriate feedback compensation value C3 is calculated according to the magnitude of the torque ripple.

[0096] The threshold Th2 for determining a soft road surface is generally a value different from the threshold Th1 for determining an uphill road. However, depending on the actual vibration characteristics of the electric vehicle 100, etc., the threshold Th2 may be the same as the threshold Th1.

[0097] In this embodiment, as described above, the gain setting unit 716 determines a soft road surface and / or an uphill road based on the estimated disturbance torque T mf obtained from the final torque command value T m and the rotational speed ω d ^, and the gains K fb2 , K fb3Adjust it. However, not limited to this, the gain setting unit 716, for example, instead of the disturbance torque estimated value T d ^, based on the drive torque target value T m or the final torque command value T mf can perform similar determination and adjustment.

[0098] However, when making the above determination and adjustment based on the drive torque target value T m or the final torque command value T mf , compared with the case of making the above determination and adjustment based on the disturbance torque estimated value Td^, it becomes a simpler determination and adjustment. This is because the determination based on the disturbance torque estimated value T d ^ is almost directly a determination based on the running resistance, while the determination based on the drive torque target value T m or the final torque command value T mf is a determination that it is at least a running scene where high torque is required.

[0099] Also, regardless of the magnitude of the torque output by the electric motor 4, if the values of the gain K fb2 and / or the gain K fb3 are set to large values throughout, high-frequency noise may occur. For this reason, when the running resistance is large as described above, or when high torque is required, by setting the gain K fb2 and / or the gain K fb3 to large values, while ensuring the stability of control, vibration damping control suitable for each running scene is particularly realized.

[0100] As described above, the electric vehicle 100 of the present embodiment includes three systems of feedback compensation value calculation units, namely, a first feedback compensation value calculation unit 711, a second feedback compensation value calculation unit 712, and a third feedback compensation value calculation unit 713, in a feedback compensator 702 which is one of the elements for realizing the vibration damping control process.

[0101] The first feedback compensation value calculation unit 711 is the most basic and main feedback element for suppressing vibrations that can occur regardless of running resistance such as torsional vibrations in the wheel drive system. In contrast, the second feedback compensation value calculation unit 712 and the third feedback compensation value calculation unit 713 are auxiliary feedback elements for suppressing additional vibrations that occur in specific driving scenes with high running resistance, such as soft road surfaces like sand or uphill roads.

[0102] Therefore, the feedback compensation value C1 output by the first feedback compensation value calculation unit 711 can be referred to as the main feedback compensation value or the first feedback compensation value in relation to the feedback compensation values C2 and C3. Also, the gain K used in the first feedback compensation value calculation unit 711 fb1 is the main feedback gain, the first feedback gain, or the first gain in relation to the gain K fb2 and the gain K. fb3 can be referred to as such.

[0103] And the feedback compensation value C2 output by the second feedback compensation value calculation unit 712 and / or the feedback compensation value C3 output by the third feedback compensation value calculation unit 713 can be referred to as the sub-feedback compensation value or the second feedback compensation value in relation to the feedback compensation value C1. Also, the gain K used in the second feedback compensation value calculation unit 712 fb2 and the gain K used in the third feedback compensation value calculation unit 13 fb3 are the sub-feedback gain, the second feedback gain, or the second gain in relation to the gain K. fb1 can be referred to as such.

[0104] <Function> Hereinafter, the function related to the vibration control of the electric vehicle 100 configured as described above will be described.

[0105] FIG. 12 shows the torque T and the rotational speed N when the vibration control of the comparative example and the vibration control of the present embodiment are implemented on sand.m , the vertical acceleration G UD , and the vertical movement amount δ UD is a time chart showing the transition of. The vibration control of the comparative example here is vibration control that only has the first feedback compensation value calculation unit 711 in the feedback compensator 702 and does not have the second feedback compensation value calculation unit 712 and the third feedback compensation value calculation unit 713.

[0106] FIGS. 12(A) to (D) are the torque T, the rotational speed N when the vibration control of the comparative example is performed on sandy ground m , the vertical acceleration G UD , and the vertical movement amount δ UD is a time chart showing the transition of. FIGS. 12(E) to (H) are the torque T, the rotational speed N when the vibration control of the present embodiment is performed on sandy ground m , the vertical acceleration G UD , and the vertical movement amount δ UD is a time chart showing the transition of. Due to the influence of the tire sinking into the sandy ground, the running resistance in the forward direction increases, and as a result, the disturbance torque estimated value T d ^ is always a positive value.

[0107] As shown in FIG. 12(A), from the state where the electric vehicle 100 is stopped at time t0, assume that the driver steps on the accelerator and the drive torque target value T m is input according to the ramp function. In the vibration control of the comparative example, only the first feedback compensation value calculation unit 711 is provided in the feedback compensator 702, and the second feedback compensation value calculation unit 712 is not provided. Therefore, in the vibration control of the comparative example, as shown in FIGS. 12(B) to (D), at times t1 to t4 after time t0, the rotational speed N m , the vertical acceleration G UD , and the vertical movement amount δ UD vibrates periodically and continuously. This indicates that vertical vibration occurs due to the sinking of the drive wheels 9a, 9b into the sandy road surface. That is, in the vibration control of the comparative example, the second torque target value T m2As a result, only the feedback compensation value C1 is fed back, suppressing the torsional vibration of the wheel drive system. However, vertical vibration occurs due to the sinking of the drive wheels 9a and 9b into the sandy road surface.

[0108] On the other hand, as shown in Fig. 12(E), also in the electric vehicle 100 that implements the vibration damping control of the present embodiment, from the state where the electric vehicle 100 is stopped at time t0, the driver steps on the accelerator, and the drive torque target value T m is input according to the ramp function. However, in the vibration damping control of the present embodiment, in addition to the first feedback compensation value calculation unit 711, the feedback compensator 702 has a second feedback compensation value calculation unit 712. Therefore, in the vibration damping control of the present embodiment, as shown in Figs. 12(F) to (H), at times t1 to t4 after time t0, compared with the case of implementing the vibration damping control of the comparative example, the rotational speed N m , the vertical acceleration G UD , and the vertical movement amount δ UD are suppressed. That is, as the second torque target value T m2 , as a result of feeding back the sum value of the feedback compensation value C1 and the feedback compensation value C2, in the vibration damping control of the present embodiment, not only the torsional vibration of the wheel drive system but also the vertical vibration due to the sinking of the drive wheels 9a and 9b into the sandy road surface is suppressed.

[0109] In particular, in the vibration damping control of the present embodiment, the gain K fb2 of the second feedback compensation value calculation unit 712 is adjusted according to the disturbance torque estimated value T d ^, so that the vertical vibration is suppressed between time t0 and the very early times t1 to t2.

[0110] Fig. 13 shows the drive shaft torque T D / S and the rotational speed N m when the vibration damping control of the comparative example and the present embodiment are implemented on an uphill road.It is a time chart showing the transition of . Here, the vibration control of the comparative example only has the first feedback compensation value calculation unit 711 in the feedback compensator 702, and does not have the second feedback compensation value calculation unit 712 and the third feedback compensation value calculation unit 713.

[0111] Figures 13(A) and (B) are time charts showing the transition of the drive shaft torque T D / S and the rotational speed N m when the vibration control of the comparative example is implemented on the uphill road. Also, Figures 13(C) and (D) are time charts showing the transition of the drive shaft torque T D / S and the rotational speed N m when the vibration control of this embodiment is implemented on the uphill road. Note that on the uphill road, the running resistance in the forward direction is large, and as a result, the disturbance torque estimated value T d ^ is always a positive value. Also, here, it is assumed that from the state where the electric vehicle 100 is stopped at time t0, the driver steps on the accelerator and the drive torque target value T m is input according to the ramp function.

[0112] In the vibration control of the comparative example, the feedback compensator 702 does not have the third feedback compensation value calculation unit 713 for suppressing the vibration related to the torque ripple generated on the uphill road. For this reason, not only the torsional vibration of the wheel drive system but also the torque ripple due to cogging occurs. In the vibration control of the comparative example, as shown in Figures 13(A) and (B), relatively large vibrations occur in the drive shaft torque T D / S and the rotational speed N m . As a result, vibrations caused by torque ripple occur in the vehicle body. That is, in the vibration control of the comparative example, only the feedback compensation value C1 is fed back as the second torque target value T m2 , so although the torsional vibration of the wheel drive system is suppressed, vibrations caused by torque ripple occur.

[0113] On the other hand, in the electric vehicle 100 that implements the vibration control of the present embodiment, in addition to the first feedback compensation value calculation unit 711, the feedback compensator 702 has a third feedback compensation value calculation unit 713. Therefore, in the vibration control of the present embodiment, as shown in FIGS. 13(C) and 13(D), the vibration of the drive shaft torque T D / S and the rotational speed N m is suppressed. That is, as the second torque target value T m2 , as a result of feeding back the sum value of the feedback compensation value C1 and the feedback compensation value C3, in the vibration control of the present embodiment, not only the torsional vibration of the wheel drive system but also the vibration related to the torque ripple is suppressed. Therefore, according to the vibration control of the present embodiment, the electric vehicle 100 can start and accelerate smoothly on the uphill road.

[0114] In particular, in the vibration control of the present embodiment, the gain K fb3 of the third feedback compensation value calculation unit 713 is adjusted according to the disturbance torque estimated value T d ^. Also, in the vibration control of the present embodiment, the characteristics of the band-pass filter H 4 (s) that constitutes the third feedback compensation value calculation unit 713 are appropriately adjusted according to the rotational speed ω m . Therefore, in the vibration control of the present embodiment, the vibration related to the torque ripple is accurately suppressed from the time t0 to about the very initial time t1.

[0115] <First Modification> In the above embodiment, the two-wheel drive (2WD) electric vehicle 100 that drives the pair of left and right drive wheels 9a and 9b using one electric motor 4 has been described. However, the present invention is also suitable for a four-wheel drive (4WD) electric vehicle 1200.

[0116] FIG. 14 is a block diagram showing the configuration of an electric vehicle 1200 according to the first modification. As shown in FIG. 14, the 4WD electric vehicle 1200 includes, for example, a front drive system 1201f, a rear drive system 1201r, a battery 1210 and a motor controller 1220 common to the front drive system 1201f and the rear drive system 1201r.

[0117] The front drive system 1201f includes a front inverter 3f, a front drive motor 4f, a front speed reducer 5f, a front rotation sensor 6f, a front current sensor 7f, a front drive shaft 8f, and a pair of front drive wheels 9af, 9bf. The rear drive system 1201r includes a rear inverter 3r, a rear drive motor 4r, a rear speed 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, 9br.

[0118] 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 current i uf , i vf , i wf and the rear current i ur , i vr , i wr 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.

[0119] The battery 1210 is one or more batteries corresponding to the battery 1 of the electric vehicle 100. The battery 1210 supplies 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 the input of regenerative power.

[0120] 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.

[0121] <Second Modified Example> In the above embodiments and the like, the disturbance torque estimated value T d ^, according to which the gain K fb2 , K fb3 is set, there is a scene where the second feedback compensation value calculation unit 712 and / or the third feedback compensation value calculation unit 713 becomes substantially invalid. However, in principle, the second feedback compensation value calculation unit 712 and the third feedback compensation value calculation unit 713 are always valid. However, this is not limited thereto, and for example, depending on the setting of the electric vehicle 100 by the driver such as the selection of the driving mode, the second feedback compensation value calculation unit 712 and the third feedback compensation value calculation unit 713 may be more explicitly enabled or disabled.

[0122] FIG. 15 is a block diagram of the vibration control according to the second modified example. In the vibration control shown in FIG. 15, a general switch 1501 is provided in the path where the estimated disturbance d^ is input to the second feedback compensation value calculation unit 712 and the third feedback compensation value calculation unit 713. The other configurations are the same as those in the above embodiments. The switch 1501 is turned on / off, for example, by the selection of the driving mode of the electric vehicle 100. Therefore, in the vibration control shown in FIG. 15, the compensation by the second feedback compensation value calculation unit 712 and the third feedback compensation value calculation unit 713 is enabled only when additional vibration control is explicitly enabled by the selection of the driving mode.

[0123] FIG. 16 is a block diagram of vibration control according to a second modification. In the vibration control shown in FIG. 16, switches 1502 and 1503 are individually provided in the paths through which the estimated disturbance d^ is input to the second feedback compensation value calculation unit 712 and the third feedback compensation value calculation unit 713, respectively. The other configurations are the same as those in the above embodiment. These switches 1502 and 1503 are turned on / off, for example, by selecting the driving mode of the electric vehicle 100. Therefore, in the vibration control shown in FIG. 16, the second feedback compensation value calculation unit 712 is activated only when the compensation function for the vertical vibration generated on a soft road surface such as sand is explicitly turned on by selecting the driving mode. Also, the third feedback compensation value calculation unit 713 is activated only when the compensation function for the vibration caused by the torque ripple generated on an uphill road is explicitly turned on by selecting the driving mode.

[0124] As described above, by explicitly turning on / off the second feedback compensation value calculation unit 712 and / or the third feedback compensation value calculation unit 713 by selecting the driving mode or the like, the calculation load in a scene where compensation by these is unnecessary is reduced. Also, overcompensation is surely prevented.

[0125] As described above, the control method for an electric vehicle according to the present embodiment and the like is a control method for an electric vehicle 100 including an electric motor 4 as a drive source. In this control method for an electric vehicle, based on vehicle information, a torque target value (drive torque target value T m ), which is a target value related to the drive torque of the electric vehicle 100, is set. Also, based on a parameter (rotation speed ω m ) representing the rotation state of the electric motor 4 and the transfer characteristic Gp(s) of the vehicle model of the electric vehicle 100, a basic feedback compensation value (estimated disturbance d^) is calculated. By multiplying the basic feedback compensation value by a first gain (K fb1 ), a first feedback compensation value (feedback compensation value C1) is calculated. On the other hand, a predetermined specific frequency component is extracted from the basic feedback compensation value, and a second gain (K fb2 or K fb3By multiplying by (), a second feedback compensation value (feedback compensation value C2 or C3) is calculated. The torque target value (drive torque target value T m ) is corrected by the first feedback compensation value (feedback compensation value C1) and the second feedback compensation value (feedback compensation values C2 and / or C3), thereby calculating a torque command value (final torque command value T mf ). Then, the electric motor 4 is driven based on the torque command value calculated in this way.

[0126] As described above, in the control method of the electric vehicle according to this embodiment and the like, not only the first feedback compensation value for compensating the torsional vibration of the wheel drive system but also the second feedback compensation value for suppressing the vibration of the vehicle body due to other factors are used. Based on this, the electric motor 4 is driven according to the corrected torque target value. Therefore, in addition to the vibration of the vehicle body caused by the torsional vibration of the wheel drive system, the vibration of the vehicle body due to factors other than the torsional vibration of the wheel drive system is suppressed.

[0127] For example, when the running resistance of the road surface is high because the vehicle is running on a soft road surface such as sand, or when high torque is required when running on an uphill road, not only the torsional vibration of the wheel drive system but also the vibrations inherent in these running scenes are accurately removed or reduced. As a result, even in the scenes of running on a soft road surface such as sand or an uphill road, the electric vehicle 100 can start and / or accelerate smoothly.

[0128] In the control method of the electric vehicle according to the above embodiment and the like, the larger the torque output by the electric motor 4, the more the second gain, gain K fb2 and / or gain K fb3 is adjusted to be larger. In this way, in the running scene where the torque output by the electric motor 4 is large, if the second gain, gain K fb2 and / or gain K fb3 is set to be larger, in a soft road surface such as sand or an uphill road, while achieving both running performance and stability, the torsional vibration of the wheel drive system and the vibrations inherent in each running scene are suppressed.

[0129] In the method for controlling an electric vehicle according to the above-described embodiment and the like, the specific frequency component is the natural vibration frequency component of the electric vehicle 100. In this way, by extracting the frequency component of the natural vibration occurring in a specific driving scene as the specific frequency component, the natural vibration occurring on a soft road surface such as sand or an uphill road is accurately suppressed.

[0130] In the method for controlling an electric vehicle according to the above-described embodiment and the like, the specific frequency component is at least the frequency component of the vertical vibration generated in the electric vehicle 100 according to the suspension characteristics of the tires and the vehicle body of the electric vehicle 100, and the sinking characteristics of the tires on a soft road surface such as sand (sand vertical vibration frequency f sand ). Thereby, in addition to the torsional vibration of the wheel drive system, at least the vertical vibration generated when traveling on a soft road surface such as sand is accurately compensated. In particular, when traveling on sand among soft road surfaces, the vertical vibration is likely to appear significantly. Therefore, the specific frequency component preferably includes at least the sand vertical vibration frequency f sand .

[0131] Also, in the method for controlling an electric vehicle according to the above-described embodiment and the like, the specific frequency component includes at least the frequency components f x , f y of the torque ripple, and is changed according to the parameter (rotation speed ω m ) representing the rotation state of the electric motor 4. Thereby, in a driving scene where the driving resistance is high and high torque is required, such as an uphill road, the vibration generated by the torque ripple is accurately suppressed.

[0132] In the control method of the electric vehicle according to the above embodiment, the specific frequency component preferably includes a plurality of frequency components. When extracting a plurality of frequency components as the specific frequency component, the vibrations of these respective frequency components are accurately suppressed. In particular, torque ripples that occur in a driving scene where the running resistance is high, such as an uphill road, and high torque is required, include torque ripples of a plurality of orders such as the X-th order and the Y-th order. Therefore, as described above, when the specific frequency component includes a plurality of frequency components corresponding to the X-th order, the Y-th order, etc., the vibration caused by the torque ripple is particularly accurately suppressed.

[0133] In the above embodiment and the like, the disturbance torque estimated value T d ^, the drive torque target value T m , or the absolute value of the torque command value such as the final torque command value T mf is compared with preset threshold values Th1 and Th2, and a driving scene in which the absolute value of the torque command value is equal to or greater than the threshold values Th1 and Th2 is discriminated. Then, when the absolute value of the torque command value is equal to or greater than the threshold values Th1 and Th2, feedback compensation values C2 and C3, which are the second feedback compensation values, are calculated.

[0134] The unique vibrations that appear in a specific driving scene such as a sandy road or an uphill road are likely to occur generally when high torque is required. Therefore, as described above, if the feedback compensation values C2 and C3, which are the second feedback compensation values, are calculated in a driving scene where high torque is required, the unique vibrations that occur only in a specific driving scene are simply and accurately suppressed.

[0135] In the above embodiment, in particular, based on the torque command value (final torque command value T mf ) and the parameter (rotation speed ω m ) representing the rotation state of the electric motor 4, the disturbance torque estimated value T d ^, which is the estimated value of the disturbance torque acting on the electric vehicle 100, is calculated. Then, by comparing the absolute value of the disturbance torque estimated value T d ^ with preset threshold values Th1 and Th2, the disturbance torque estimated value T dA driving scene in which the absolute value of ^ is equal to or greater than these threshold values Th1 and Th2 is determined. Then, disturbance torque estimated value T d When the absolute value of ^ is equal to or greater than these threshold values Th1 and Th2, feedback compensation values C2 and C3, which are the second feedback compensation values, are calculated.

[0136] In this way, based on the disturbance torque estimated value T d ^, a driving scene with high driving resistance is determined, and when the driving scene has high driving resistance, feedback compensation values C2 and C3, which are the second feedback compensation values, are calculated. As a result, a specific driving scene with high driving resistance, such as a sandy road or an uphill road, can be determined particularly accurately. As a result, the inherent vibration that appears in a specific driving scene, such as a sandy road or an uphill road, can be suppressed particularly accurately.

[0137] As described above, the embodiments of the present invention have been described. However, the configurations described in the above embodiments and each modification are merely examples of the application examples of the present invention, and are not intended to limit the technical scope of the present invention.

[0138] For example, in the above embodiments and the like, as a parameter representing the rotational state of the electric motor 4, the rotational speed ω m is used. However, instead of the rotational speed ω m , a parameter correlated with the rotational state of the electric motor 4, such as the number of revolutions N m , may be used for vibration control and the like.

Claims

1. A method for controlling an electric vehicle equipped with an electric motor as a drive source, comprising: Based on vehicle information, setting a torque target value which is a target value related to the driving torque of the electric vehicle; Calculating a basic feedback compensation value including at least the frequency band of torsional vibration of the vehicle drive system based on a parameter representing the rotational state of the electric motor and the vehicle model of the electric vehicle; Calculating a first feedback compensation value by multiplying the basic feedback compensation value by a first gain; Extracting a predetermined specific frequency component from the basic feedback compensation value and calculating a second feedback compensation value by multiplying the specific frequency component by a second gain; Calculating a torque command value by correcting the torque target value with the first feedback compensation value and the second feedback compensation value; Driving the electric motor based on the torque command value; A method for controlling an electric vehicle.

2. The method for controlling an electric vehicle according to claim 1, wherein: The second gain is adjusted so that it increases as the torque output by the electric motor increases; A method for controlling an electric vehicle.

3. The method for controlling an electric vehicle according to claim 1 or 2, wherein: The specific frequency component is a natural vibration frequency component of the electric vehicle; A method for controlling an electric vehicle.

4. The method for controlling an electric vehicle according to claim 3, wherein: The specific frequency component includes at least the frequency component of the vertical vibration generated in the electric vehicle according to the suspension characteristics of the tires and the vehicle body of the electric vehicle and the sinking characteristics of the tires on a soft road surface; A method for controlling an electric vehicle.

5. The method for controlling an electric vehicle according to claim 3, wherein: The specific frequency component includes at least the frequency component of torque ripple and is changed according to the parameter; A method for controlling an electric vehicle.

6. The method for controlling an electric vehicle according to any one of claims 3 to 5, wherein: The specific frequency component includes a plurality of frequency components; A method for controlling an electric vehicle.

7. The method for controlling an electric vehicle according to any one of claims 1 to 6, wherein: By comparing the absolute value of the torque command value with a predetermined threshold value, discriminating a driving scene in which the absolute value of the torque command value is equal to or greater than the threshold value; When the absolute value of the torque command value is equal to or greater than the threshold value, calculating the second feedback compensation value; A method for controlling an electric vehicle.

8. A control method for an electric vehicle according to any one of claims 1 to 6, calculating a disturbance torque estimation value, which is an estimation value of a disturbance torque acting on the electric vehicle, based on the torque command value and the parameter; determining a driving scene in which the absolute value of the disturbance torque estimation value is equal to or greater than a preset threshold value by comparing the absolute value of the disturbance torque estimation value with the preset threshold value; calculating the second feedback compensation value when the absolute value of the disturbance torque estimation value is equal to or greater than the threshold value; A control method for an electric vehicle.

9. A control device for an electric vehicle that controls the drive of an electric vehicle equipped with an electric motor as a drive source, a torque target value setting unit that sets a torque target value, which is a target value related to the drive torque of the electric vehicle, based on vehicle information; a basic feedback compensation value calculation unit that calculates a basic feedback compensation value including at least a frequency band of torsional vibration of a vehicle drive system based on a parameter representing a rotational state of the electric motor and a vehicle model of the electric vehicle; a first feedback compensation value calculation unit that calculates a first feedback compensation value by multiplying the basic feedback compensation value by a first gain; a second feedback compensation value calculation unit that extracts a specific frequency component preset from the basic feedback compensation value and calculates a second feedback compensation value by multiplying the specific frequency component by a second gain; a torque command value calculation unit that calculates a torque command value by correcting the torque target value with the first feedback compensation value and the second feedback compensation value; a drive control unit that drives the electric motor based on the torque command value; A control device for an electric vehicle, comprising.

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