Control method for electric vehicle, control device for electric vehicle

Abstract

To provide a control method for an electric vehicle which can reduce vibration of a drive force transmission system.SOLUTION: A control method for an electric vehicle calculates a second f-axis current command value which is the same as a first f-axis current command value when there is no disturbance for a drive force transmission system of the electric vehicle, and is higher than the first f-axis current command value when an absolute value of a motor torque command value is equal to or less a predetermined value and the disturbance is detected; estimates a magnet flux estimation value on the basis of a first vertical axis current command value and the second f-axis current command value; calculates a first torque command value on the basis of a first lateral axis current command value and the magnet flux estimation value; calculates a vibration damping torque command value obtained by performing arithmetic processing of suppressing vibration of the drive force transmissions system on the first torque command value; calculates a second lateral axis current command value on the basis of the magnet flux estimation value and the vibration damping torque command value; and controls a stator current on the basis of the second lateral axis current command value and the first vertical axis current command value, and controls a rotor current on the basis of the second f-axis current command value.SELECTED DRAWING: Figure 9

Description

[Technical Field]

[0001] The present invention relates to a control method for an electric vehicle and a control device for an electric vehicle. [Background technology]

[0002] Patent Document 1 discloses the application of vibration suppression control to a field-winding synchronous motor in order to reduce torsional vibration of the drive shaft connecting the motor and the drive wheels. In Patent Document 1, vibration is suppressed by controlling the q-axis current of the motor. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2000-270589 Summary of the Invention [Problem to be solved by the invention]

[0004] However, when the motor is stopped, for example, and the f-axis current applied to the rotor winding (field winding) is set to a small value, it is difficult to sufficiently reduce vibrations simply by controlling the q-axis current.

[0005] The present invention aims to provide a control method for an electric vehicle and a control device for an electric vehicle that can reduce vibration in a driving force transmission system even when the f-axis current applied to the rotor winding is set to a small value. [Means for solving the problem]

[0006] A control method for an electric vehicle according to the present invention uses a field-winding type synchronous motor including a rotor having a rotor winding and a stator having a stator winding as a drive motor, sets a motor torque command value based on vehicle information, calculates a first vertical-axis current command value that is a vertical-axis command value for an orthogonal component of the stator current, a first quadrature-axis current command value that is a quadrature-axis command value for the stator current, and a first f-axis current command value that is a rotor current command value, based on the motor torque command value and the vehicle information, and controls the stator current using the first vertical-axis current command value and the first quadrature-axis current command value, and controls the rotor current using the first f-axis current command value. This control method calculates a second f-axis current command value that is the same as the first f-axis current command value when there is no disturbance to the driving force transfer system of the electric vehicle, but is higher than the first f-axis current command value when the absolute value of the motor torque command value is equal to or less than a predetermined value and a disturbance is detected, estimates a magnetic flux estimate based on the first vertical axis current command value and the second f-axis current command value, calculates a first torque command value based on the first quadrature axis current command value and the magnetic flux estimate value, calculates a vibration-damping torque command value by performing a calculation process on the first torque command value to suppress vibrations in the driving force transfer system, and calculates a second quadrature axis current command value based on the magnetic flux estimate and the vibration-damping torque command value, and controls the stator current based on the second quadrature axis current command value and the first vertical axis current command value, and controls the rotor current based on the second f-axis current command value. [Effects of the Invention]

[0007] According to the present invention, even when the f-axis current applied to the rotor winding is set to a small value, the f-axis current is increased in response to a disturbance, thereby making it possible to sufficiently suppress vibrations in the driving force transmission system that may occur due to disturbances. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a diagram showing an example of the basic configuration of an electric vehicle equipped with a control device for an electric vehicle according to this embodiment. [Figure 2] FIG. 2 is a flowchart of the motor current control performed by the control device of this embodiment. [Figure 3] FIG. 3 is a diagram showing an example of an accelerator opening-torque table. [Figure 4] FIG. 4 is a block diagram showing a part of the control device for the electric vehicle of this embodiment. [Figure 5] FIG. 5 is a block diagram of the q-axis current control unit. [Figure 6] FIG. 6 is a block diagram of the d-axis current control unit. [Figure 7] FIG. 7 is a block diagram of the f-axis current control unit. [Figure 8] FIG. 8 is a block diagram of the vibration suppression control unit of this embodiment. [Figure 9] FIG. 9 shows a control flow of the vibration suppression control unit of this embodiment. [Figure 10] FIG. 10 is a block diagram of the flux estimator. [Figure 11] FIG. 11 is a block diagram of the vibration damping torque command value calculation unit. [Figure 12] FIG. 12 is a diagram showing a model of the drive train system of an electric vehicle. [Figure 13] FIG. 13 is a diagram showing the frequency characteristics of the band-pass filter H(s). [Figure 14] FIG. 14 is a time chart showing the response of the drive shaft torque, drive motor rotation speed, q-axis current, d-axis current, and f-axis current when the parking lock is released, comparing the cases where control by the control device for an electric vehicle of this embodiment is not executed with the case where it is executed. DETAILED DESCRIPTION OF THE INVENTION

[0009] [Electric vehicle system configuration] 1 is a block diagram showing the system configuration of an electric vehicle 1 equipped with a control device (control method) for an electric vehicle 1 according to this embodiment. The electric vehicle 1 is an automobile that has a motor 6 (drive motor) as part or all of the vehicle's drive source and can run using the driving force of the motor 6, and includes electric automobiles and hybrid automobiles.

[0010] The motor controller 2 (control device) receives the vehicle speed V, the accelerator opening, and the electrical angle θ of the motor 6. re , the three-phase AC current (iu, iv, iw) of the stator of the motor 6, and the f-axis current i of the rotor of the motor 6 f Signals indicating vehicle conditions such as the above are input as digital signals. The motor controller 2 generates a PWM signal for controlling the motor 6 based on the input signal (vehicle information). Also, based on the generated PWM signal, it generates a drive signal for the inverter 3 via a drive circuit.

[0011] The inverter 3 has two pairs of switching elements (e.g., power semiconductor elements such as IGBTs and MOS-FETs) provided for each phase to control the current in the stator of the motor 6, and by turning the switching elements on and off, it converts the direct current supplied from the battery 4 into alternating current and passes the desired current through the stator winding of the motor 6.

[0012] The inverter 3 also has two pairs of switching elements on both ends of the rotor winding for controlling the current in the rotor of the motor 6, and by turning the switching elements on and off in response to a drive signal, a desired current flows from the battery 4 to the rotor winding. However, if the current flowing to the rotor is unidirectional, the two diagonally opposite switching elements of the two pairs of switching elements may be replaced with diodes.

[0013] Motor 6 (three-phase AC motor) generates driving force using AC current supplied from inverter 3, and transmits the driving force to left and right drive wheels 81, 82 via speed reducer 7 and drive shaft 8. When motor 6 is rotated by drive wheels 81, 82 while the vehicle is running, it generates regenerative driving force, thereby recovering the kinetic energy of the vehicle as electrical energy. In this case, inverter 3 converts the AC current generated during regenerative operation of motor 6 into DC current and supplies it to battery 4.

[0014] The current sensor 5 detects the three-phase AC current (iu, iv, iw) flowing through the stator of the motor 6 and the f-axis current i fHowever, since the sum of the three-phase AC currents (iu, iv, iw) is 0, the currents of any two phases may be detected and the current of the remaining phase may be calculated.

[0015] The rotation sensor 9 is, for example, a resolver or an encoder, and detects the electrical angle θ of the rotor of the motor 6. re Detect.

[0016] [System-wide control flow] 2 is a flowchart of the motor current control performed by the control device (motor controller 2) of this embodiment. The processes from step S201 to step S204 are executed at regular intervals while the vehicle system is running.

[0017] In step S201, a signal indicating the vehicle state (vehicle information) is input to the motor controller 2. Here, the vehicle speed V (km / h), the accelerator opening (%), the electrical angle θ of the motor 6, re Also input are the rotation speed Nm (rpm) of the motor 6, the three-phase AC current (iu, iv, iw) flowing through the stator of the motor 6, the f-axis current if flowing through the rotor of the motor 6, the DC voltage value Vdc (V) of the battery 4, a brake signal, and a park lock release signal (shift information, a signal indicating that the shift lever of the electric vehicle 1 is in a position other than park).

[0018] The vehicle speed V (km / h) is acquired from a vehicle speed sensor (not shown) or from another controller through communication.

[0019] The accelerator opening (%) is acquired from an accelerator opening sensor (not shown) or acquired via communication from another controller (not shown) such as a vehicle controller.

[0020] Motor 6 electrical angle θ re (rad) is acquired from the rotation sensor 9. re is the electrical angle θ re can be found by differentiating

[0021] The rotation speed Nm [rpm] of the motor 6 is expressed as the electrical angular velocity ω re Divide by the number of poles of the electric motor to get the mechanical angular velocity ω rm After calculating [rad / s], multiply it by the unit conversion factor (60 / 2π) from [rad / s] to [rpm] to calculate the value.

[0022] The three-phase AC current (iu, iv, iw) [A] flowing through the stator of the motor 6, and the f-axis current i flowing through the rotor of the motor 6 f [A] is obtained from the current sensor 5.

[0023] DC voltage value V dc [V] is detected by a voltage sensor (not shown) provided on the DC power supply line between the battery 4 and the inverter 3. The DC voltage value V dc [V] may be detected from a signal relating to the power supply voltage value transmitted from a battery controller (not shown).

[0024] The brake signal is detected as a hardware signal or acquired via communication from another controller such as a shift controller.

[0025] The park lock release signal is obtained via communication from the shift position signal, the park lock release switch signal on the shift knob, and other controllers such as the shift controller.

[0026] In step S202, the motor controller 2 (motor torque command value setting means) sets the motor torque command value Tm as the basic target torque. * Specifically, the motor controller 2 sets the motor torque command value Tm by referring to the accelerator opening-torque table shown in FIG. 3 based on the accelerator opening and vehicle speed V input in step S201. * However, the accelerator opening-torque table is an example and is not limited to the one shown in FIG.

[0027] In step S203, the motor controller 2 (more specifically, the vibration control unit 211 (FIGS. 4 and 8)) performs vibration control calculation processing. Specifically, the motor torque command value Tm set in step S202 is calculated. * , mechanical angular velocity ω rm The second q-axis current command value i (described later) is input to suppress vibrations (torsional vibrations of the drive shaft 8, etc.) in the drive force transmission system (a mechanism that transmits the drive force from the motor 6 to the drive shaft 8 (drive wheels 81, 82)) without sacrificing the torque response of the drive shaft 8. q2 * (second quadrature axis current command value), first d-axis current command value i d1 * (first vertical axis current command value), second f-axis current command value i f2 * The details of the vibration suppression control calculation process will be described later (Fig. 9).

[0028] In step S204, the motor controller 2 (FIG. 4) performs current control calculation processing. Specifically, the second q-axis current command value i q2 * , the first d-axis current command value i d1 * , the second f-axis current command value i f2 * Based on this, the PWM_Duty drive signal (D uu * ,D ul * ,D vu * ,D vl * ,D wu * ,D wl * ), and the PWM_Duty drive signal (D fu * ,D fl * )

[0029] [Motor Controller 2] 4 is a block diagram showing a part of the control device (motor controller 2) of the electric vehicle 1 of this embodiment. The motor controller 2 of this embodiment executes the vibration damping control calculation process and the current control calculation process.

[0030] The motor controller 2 of this embodiment includes a stator PWM converter 201, a rotor PWM converter 202, a look-ahead compensation unit 203, a first coordinate converter 204, a non-interference control unit 205, a q-axis current control unit 206 (current control means), a d-axis current control unit 207 (current control means), an f-axis current control unit 208 (current control means), a voltage command value calculation unit 209, a second coordinate converter 210, and a vibration suppression control unit 211.

[0031] The stator PWM converter 201 generates a three-phase voltage command value (v u * ,v v * ,v w * ) based on the PWM_Duty drive signal (D uu * ,D ul * ,D vu * ,D vl * ,D wu * ,D wl * )

[0032] The rotor PWM converter 202 outputs the f-axis voltage command value (v f * ) based on the PWM_Duty drive signal (D fu * ,D fl * )

[0033] The look-ahead compensation unit 203 calculates the electrical angle θ re and electrical angular velocity ω re Enter the electrical angle θ re With respect to the electrical angular velocity ω reThe electrical angle after look-ahead compensation θ is calculated by adding the product of the dead time of the control system and the re ' is required.

[0034] The first coordinate converter 204 (three-phase / dq-axis coordinate converter) converts the three-phase AC coordinate system (u-axis, v-axis, w-axis) into an electrical angular velocity ω re Specifically, the u-phase current iu, the v-phase current iv, and the electrical angle θ re and calculate the d-axis current i d , q-axis current i q Calculate.

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[0035] The decoupling control unit 205 controls the electrical angular velocity ω re and the d-axis current reference response i d_ref , q-axis current reference response i q_ref , f-axis current reference response i f_ref , the differential value s·i of the d-axis current reference response d_ref , the differential value s·i of the f-axis current reference response f_ref The decoupling voltage (v d_dcpl ,v q_dcpl ,v f_dcpl The voltage equation for a wound-field synchronous motor is given by the following equation (2).

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[0036] however, id: d-axis current iq: q-axis current if : f-axis current vd: d-axis voltage vq: q-axis voltage vf: f-axis voltage Ld: d-axis inductance Lq: q-axis inductance Lf: f-axis inductance Mf: Mutual inductance between stator and rotor Ld': d-axis dynamic inductance Lq': q-axis dynamic inductance Lf': f-axis dynamic inductance Mf': Dynamic mutual inductance between the stator and rotor Ra: Stator winding resistance Rf: Rotor winding resistance ω re : electrical angular velocity Furthermore, s is a Laplace operator. If decoupling control section 205 functions ideally, the voltage equation of equation (2) can be diagonalized as shown in the following equation (3).

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[0037] In other words, the characteristics from voltage to current on the d-axis, q-axis, and f-axis are one-time lags as shown in the following equations (4), (5), and (6), respectively.

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[0038] The q-axis current control unit 206, the d-axis current control unit 207, and the f-axis current control unit 208 each control a second q-axis current command value i q2 * , the first d-axis current command value i d1 * , the second f-axis current command value i f2 * Then, the measured (actual) q-axis current i q , d-axis current i d , f-axis current i f is made to follow with the desired responsiveness without steady-state deviation.

[0039] <q-axis current control unit 206> FIG. 5 is a block diagram of the q-axis current control unit 206. The q-axis current control unit 206 includes a first-order lag responder 2061, a subtractor 2062, a proportional gain 2063, an integral gain 2064, an integrator 2065, and an adder 2066.

[0040] The first-order lag responder 2061 receives the second q-axis current command value i q2 * is input. The first-order lag responder 2061 has a first-order lag transfer characteristic that simulates the response delay of the actual current with respect to the second q-axis current command value i q2 * Therefore, the first-order lag responder 2061 superimposes the transfer characteristic on the input second q-axis current command value i q2 * to output the q-axis current reference response i q_ref Note that τ q is the q-axis current reference response time constant.

[0041] The subtractor 2062 calculates the difference between the second q-axis current command value i q2 * and the q-axis current i q (detection value) and outputs it to the proportional gain 2063 and the integral gain 2064.

[0042] The proportional gain 2063 multiplies the difference by the gain K pq and outputs it to the adder 2066. The integral gain 2064 multiplies the difference by the gain K iq and outputs it to the integrator 2065. The integrator 2065 integrates the output of the integral gain 2064 and outputs it to the adder 2066.

[0043] [[ID=​​​​​​​​​is set as shown in the following equations (7) and (8). As a result, the transfer characteristics from the q-axis current command value (the first q-axis current command value i q1 * , the second q-axis current command value i q2 * ) to the q-axis current i q can be made to match the standard response of the following equation (9).

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[0045] <d-axis current control unit 207> Fig. 6 is a block diagram of the d-axis current control unit 207. The d-axis current control unit 207 includes a first-order lag responder 2071, a subtractor 2072, a proportional gain 2073, an integral gain 2074, an integrator 2075, an adder 2076, and a differentiator 2077.

[0046] The first d-axis current command value i d1 * is input to the first-order lag responder 2071. The first-order lag responder 2071 has the transfer characteristics of a first-order lag that simulates the response delay of the actual current with respect to the first d-axis current command value i d1 * . Therefore, the first-order lag responder 2071 superimposes the transfer characteristics on the input first d-axis current command value i d1 * to output the d-axis current standard response i d_ref . Note that τ d is the d-axis current standard response time constant.

[0047] The first d-axis current command value i d1 * is input to the differentiator 2077. The differentiator 2077 differentiates the first d-axis current command value i d1 *Therefore, the differentiator 2077 has a transfer characteristic of a time differential of a first-order delay that simulates the response delay of the actual current to the input first d-axis current command value i d1 * The transfer characteristic is superimposed on the d-axis current reference response i d_ref The derivative of s·i d_ref Output.

[0048] The subtractor 2072 subtracts the first d-axis current command value i d1 * and d-axis current i d The difference between the detected value and the calculated value is output to the proportional gain 2073 and the integral gain 2074 .

[0049] The proportional gain 2073 is the gain K pd The integral gain 2074 multiplies the difference by a gain K id The result is output to an integrator 2075. The integrator 2075 integrates the output of the integral gain 2074 and outputs the result to an adder 2076.

[0050] The adder 2076 adds the output of the proportional gain 2073 and the output of the integrator 2075 to obtain the first d-axis voltage command value v d_dsh Output.

[0051] Here, the gain K pd , and gain K id are set as shown in the following formulas (10) and (11). As a result, the d-axis current command values ​​(first d-axis current command value id1*, second d-axis current command value i d2 * ) to the d-axis current i d The transfer characteristic up to can be matched to the reference response of Equation (12) shown below.

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[0052] <f-axis current control unit 208> FIG. 7 is a block diagram of the f-axis current control unit 208. The f-axis current control unit 208 includes a first-order lag responder 2081, a subtractor 2082, a proportional gain 2083, an integral gain 2084, an integrator 2085, an adder 2086, and a differentiator 2087.

[0053] The second f-axis current command value i f2 * is input to the first-order lag responder 2081. The first-order lag responder 2081 has a first-order lag transfer characteristic that simulates the response delay of the actual current with respect to the second f-axis current command value i f2 * . Therefore, the first-order lag responder 2081 superimposes the transfer characteristic on the input second f-axis current command value i f2 * to output the f-axis current reference response i f_ref . Note that τ f is the f-axis current reference response time constant.

[0054] The second f-axis current command value i f2 * is input to the differentiator 2087. The differentiator 2087 has a transfer characteristic of the time derivative of a first-order lag that simulates the response delay of the actual current with respect to the second f-axis current command value i f2 * . Therefore, the differentiator 2087 superimposes the transfer characteristic on the input second f-axis current command value i f2 * to output the differential value s·i f_ref of the f-axis current reference response.

[0055] The subtractor 2082 calculates the difference between the second f-axis current command value i f2 * and the f-axis current i f (detection value) and outputs it to the proportional gain 2083 and the integral gain 2084.

[0056] The proportional gain 2083 multiplies the difference by the gain K pf W and outputs it to the adder 2086. The integral gain 2084 multiplies the difference by the gain K ifThe result is output to an integrator 2085. The integrator 2085 integrates the output of the integral gain 2084 and outputs the result to an adder 2086.

[0057] The adder 2086 adds the output of the proportional gain 2083 and the output of the integrator 2085 to obtain the first f-axis voltage command value v f_dsh Output.

[0058] Here, the gain K pf , and gain K if is set as shown in the following formula (13) and formula (14). As a result, the f-axis current command value (first f-axis current command value i f1 * , the second f-axis current command value i f2 * ) to the f-axis current i f The transfer characteristic up to can be matched to the reference response of Equation (15) shown below.

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[0059] Returning to Figure 4, the explanation continues.

[0060] The voltage command value calculation unit 209 calculates the first q-axis voltage command value v q_dsh and the q-axis decoupling voltage v which is the output of the decoupling control unit 205. q_dpcl and the second q-axis voltage command value v q * is generated and output to the second coordinate transformer 210.

[0061] Furthermore, the voltage command value calculation unit 209 calculates the first d-axis voltage command value v d_dsh and the d-axis decoupling voltage v which is the output of the decoupling control unit 205. d_dpcl and the second d-axis voltage command value vd * is generated and output to the second coordinate transformer 210.

[0062] Furthermore, the voltage command value calculation unit 209 calculates the first f-axis voltage command value v f_dsh and the f-axis decoupling voltage v, which is the output of the decoupling control unit 205. f_dpcl and the second f-axis voltage command value v f * and outputs it to the rotor PWM converter 202.

[0063] The second coordinate converter 210 (dq-axis / three-phase coordinate converter) converts a two-axis DC coordinate system (d-axis, q-axis) into a three-phase AC coordinate system (u-axis, v-axis, w-axis). Specifically, the second d-axis voltage command value v d * , the second q-axis voltage command value v q * and the electrical angle θ after look-ahead compensation re ' is input, and the second d-axis voltage command value v d * , the second q-axis voltage command value v q * By performing coordinate transformation processing using the following equation (16), the u-phase voltage command value v u * , the voltage command value v of the v phase v * , w-phase voltage command value v w * are calculated and output.

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[0064] The vibration suppression control unit 211 receives a motor torque command value T m * , mechanical angular velocity ω rm , DC voltage value V dc , the q-axis current i detected by the current sensor 5 q , the parking lock release signal, the brake signal, and the vehicle speed V are input, and the second q-axis current command value i q2 *, the first d-axis current command value i d1 * , the second f-axis current command value i f2 * The details of the vibration suppression control calculation process (FIG. 8) will be described later.

[0065] <Vibration control unit 211> Fig. 8 is a block diagram of vibration suppression control unit 211. As shown in Fig. 8, vibration suppression control unit 211 includes a first current command value calculator 212, a second current command value calculator 213, a magnetic flux estimator 214, a first torque command value calculator 215, a vibration suppression torque command value calculator 216, and a second q-axis current command value calculator 217.

[0066] The first current command value calculator 212 (first current command value calculation means) calculates the motor torque command value T m * , motor rotation speed (mechanical angular velocity ω rm ), DC voltage value V dc When is input, the first q-axis current command value i q1 * , the first d-axis current command value i d1 * , the first f-axis current command value i f1 * , is calculated. The first q-axis current command value i q1 * , the first d-axis current command value i d1 * , and the first f-axis current command value i f1 * are the motor torque command values ​​T m * , motor rotation speed (mechanical angular velocity ω rm ), DC voltage value V dc and the first q-axis current command value i q1 * , the first d-axis current command value i d1 * , the first f-axis current command value i f1 * The above relationship can be determined by storing map data in advance in a memory and referencing this map data.

[0067] The second current command value calculator 213 (second current command value calculation means) receives the motor torque command value T m * , motor rotation speed (mechanical angular velocity ω rm ), the first f-axis current command value i f1 * , q-axis current i q (detected value), a parking lock release signal, a brake signal, and a vehicle speed V are input. Then, the second current value calculator 2112 calculates a second f-axis current command value i f2 * and outputs it to the magnetic flux estimator 214 and the f-axis current control unit 208 (FIGS. 4 and 7). The control flow will be described in detail later (FIG. 9).

[0068] The magnetic flux estimator 214 (magnetic flux estimating means) receives a first d-axis current command value i d1 * , and the second f-axis current command value i f2 * is input. Then, the magnetic flux estimator 214 calculates a magnetic flux estimation value φ^ based on the input command value and outputs it to a first torque command value calculator 215 and a second q-axis current command value calculator 217. Details of the magnetic flux estimator 214 will be described later (FIG. 10).

[0069] The first torque command value calculator 215 (torque command value calculation means) receives a first q-axis current command value i q1 * and the magnetic flux estimation value φ^ are input to the first torque command value calculator 215. The first q-axis current command value i q1 * and the estimated magnetic flux value φ^ are multiplied by the number of pole pairs p n The value multiplied by is the first torque command value T m1 * and outputs this to vibration damping torque command value calculator 216.

[0070] The vibration damping torque command value calculator 216 (vibration damping torque command value calculation means) receives the motor rotation speed (mechanical angular velocity ω rm ) and the first torque command value T m1 *is input. The vibration damping torque command value calculator 216 calculates the motor rotation speed (mechanical angular velocity ω rm ) and the first torque command value T m1 * Based on the final torque command value T mfin * (oscillation-damping torque command value) and outputs this to second q-axis current command value calculator 217. Details of oscillation-damping torque command value calculator 216 will be described later (FIG. 11).

[0071] The second q-axis current command value calculator 217 (third current command value calculation means) calculates the final torque command value T mfin * and the magnetic flux estimation value φ^ are input. The second q-axis current command value calculator 217 calculates the second q-axis current command value i q2 * and outputs this to the q-axis current control unit 206 (FIG. 4).

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[0072] [Vibration control calculation processing] 9 shows the control flow of vibration suppression control unit 211 of this embodiment. Vibration suppression control unit 211 of this embodiment has a program installed therein for executing the control method of the present invention, and executes the control flow in accordance with this program.

[0073] In the prior art (for example, Patent Document 1), the q-axis current i q Therefore, the f-axis current i f If is zero or a very small value, the desired motor torque cannot be generated. Therefore, in the scene where the parking lock is released on a slope as described below, the f-axis current i f If is zero or a very small value, there is a problem that vibration cannot be suppressed.

[0074] Specifically, the vehicle is parked on a slope with the gear shift set to P and without applying the foot brake or parking brake. In this case, the park lock mechanism is activated by the shift to P, allowing the vehicle to remain parked even when the brake is released. However, because the drive wheels 81, 82 are not fixed, the drive axle 8 twists a certain amount depending on the slope of the road when the vehicle is stopped. When attempting to start the vehicle from this stopped state, the handbrake must be applied to release the park lock. At this time, releasing the gear shift to P disengages the park lock mechanism, releasing the torsion that had accumulated in the drive axle 8, causing drive axle torsional vibration (torsional vibration caused by a disturbance to the drive force transmission system), causing the occupants to feel an unexpected shock (hereinafter, this shock will be referred to as the park lock release shock).

[0075] Therefore, in this embodiment, as shown below, the f-axis current i f Even when the value of the rotational speed is set small, the control is performed so that the torsional vibration of the drive shaft 8 due to disturbances can be sufficiently suppressed.

[0076] In the initial state (when there is no disturbance), the second f-axis current command value i output by the second current command value calculator 213 is f2 * is the first f-axis current command value i f1 * As a result, in the initial state (when there is no disturbance), the second q-axis current command value i q2 * The first f-axis current command value i f1 * is a command value that is set in response to a request from the electric vehicle side, and is set regardless of disturbances.

[0077] In step S301, the second current command value calculator 213 determines whether or not a disturbance has been detected from the park lock release or the fluctuation range of the motor rotation speed, and if YES, proceeds to step S302, and if NO, proceeds to RETURN.

[0078] In step S302, the second current command value calculator 213 calculates the motor torque command value T m * is equal to or less than a predetermined value (for example, the absolute value is 1 [N·m]), and if YES, the process proceeds to step S303, and if NO, the process proceeds to RETURN.

[0079] In step S303, the second current command value calculator 213 calculates the motor torque command value T m * is zero, and if YES, the process proceeds to step S304, and if NO, the process proceeds to step S305.

[0080] In step S304, when the second current command value calculator 213 detects a disturbance, it calculates the first f-axis current command value i f1 * The value obtained by offsetting the value by a predetermined value (a predetermined value for increasing the absolute value) is set as the second f-axis current command value i f2 * That is, when the second current command value calculator 213 detects a disturbance, it calculates the second f-axis current command value i f2 * A predetermined value is added to the motor torque command value T m * If is zero, the second f-axis current command value i f2 * By immediately increasing the value of , the shock caused by the disturbance can be quickly resolved.

[0081] In step S305, when the second current command value calculator 213 detects a disturbance, it calculates the first f-axis current command value i f1 * The value obtained by offsetting the second f-axis current command value i by a predetermined value through low-pass filter (LPF) processing (a predetermined value that increases the absolute value) is f2 *That is, when the second current command value calculator 213 detects a disturbance, it increases the first f-axis current command value i based on the characteristics (first-order response) of the low-pass filter, as shown in the following formula (18). f1 * The value converges to a value that is higher by a predetermined value (A).

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[0082] Here, the time constant (τ fa ) is, for example, the second f-axis current command value i f2 * The rising edge of the second q-axis current command value i q2 * The rise time is set to be approximately the same as the rise time of the

[0083] Motor torque command value T m * is not zero, the second f-axis current command value i f2 * If the second f-axis current command value i is increased stepwise, the motor torque may fluctuate, causing unexpected acceleration / deceleration or shocks. However, if the second f-axis current command value i is increased stepwise, the motor torque may fluctuate, causing unexpected acceleration / deceleration or shocks. f2 * By increasing the value, the motor torque fluctuation can be suppressed.

[0084] The motor torque command value T m * Even if is zero, when a disturbance is detected, the second f-axis current command value i f2 * It is also possible to increase the second f-axis current command value i by approximating the formula (18) to a linear function at a predetermined increase rate (rate limit). f2 * may be increased.

[0085] In step S306, the second current command value calculator 213 determines whether a specified time (for example, 1 [s]) has elapsed since the disturbance was detected. If the result is YES, the process proceeds to step S307, and if the result is NO, the process proceeds to step S310. Here, the specified time is a time set to determine that the shock (torsional vibration) caused by the disturbance has converged. At this time, the rotation speed Nm or the q-axis current i of the motor 6, which is affected by the disturbance, q It is determined that the fluctuation of the rotation speed Nm of the motor 6 has converged to within a predetermined threshold value after the specified time has elapsed. The specified time may be constant, or the second current command value calculator 213 may set the specified time based on the fluctuation width of the rotation speed Nm of the motor 6 caused by a disturbance (proportional to the time until the torsional current converges).

[0086] In step S307, the second current command value calculator 213 calculates the motor torque command value T m * If the answer is YES in step S307, that is, if the motor torque command value T m * When is equal to or greater than a predetermined value (when the driver is operating the accelerator), the first f-axis current command value i f1 * has a predetermined magnitude, and the motor 6 is in a state where it can generate a predetermined torque. Therefore, the second f-axis current command value i f2 * is the first f-axis current command value i f1 * Therefore, shock to the driving force transmission system due to disturbance can be suppressed without setting the vehicle speed higher than the predetermined value, and the flow can be shifted to the next step before the specified time has elapsed.

[0087] In step S308, the second current command value calculator 213 determines whether the absolute value of the vehicle speed V of the electric vehicle 1 exceeds a predetermined value (for example, 5 km / s), and if YES, proceeds to step S310, and if NO, proceeds to step S309. If the absolute value of the vehicle speed V exceeds the predetermined value even before the specified time has elapsed, it can be determined that the shock has subsided, and the process can proceed to the next flow before the specified time has elapsed.

[0088] In step S309, the second current command value calculator 213 determines whether the brake has transitioned from the ON state to the OFF state within a specified time, and if the result is YES, the process proceeds to step S310, and if the result is NO, the process proceeds to step S306. If the brake has transitioned from the ON state to the OFF state even before the specified time has elapsed, it can be determined that the shock caused by the disturbance has subsided, and the process can proceed to the next flow before the specified time has elapsed.

[0089] By executing the flow of steps S307 to S309, unnecessary power consumption can be reduced.

[0090] In step S310, the second current command value calculator 213 calculates the motor torque command value T m * is zero, and if YES, the process proceeds to step S311, and if NO, the process proceeds to step S312.

[0091] In step S311, the second current command value calculator 213 calculates the second f-axis current command value i f2 * is set as a step function to the first f-axis current command value i f1 * and transition to RETURN.

[0092] In step S312, the second current command value calculator 213 calculates the second f-axis current command value i f2 * is reduced based on the characteristics (first-order response) of the low-pass filter to obtain the first f-axis current command value i f1* Converge to and transition to RETURN.

number

[0093] Here, the time constant (τ fb ) is an arbitrary time constant greater than zero.

[0094] Motor torque command value T m * If is not zero, the second f-axis current command value i f2 * is immediately converted to the first f-axis current command value i f1 * Therefore, by providing a predetermined response characteristic, it is possible to prevent sudden changes in motor torque and to converge shocks caused by disturbances.

[0095] <Magnetic flux estimator 214> 10 is a block diagram of the magnetic flux estimator 214. The magnetic flux estimator 214 includes a transfer characteristic section 2141, a gain 2142, a transfer characteristic section 2143, a gain 2144, and an adder 2145. The transfer characteristic section 2141 and the gain 2142 configure a reluctance torque equivalent magnetic flux estimator, and the transfer characteristic section 2143 and the gain 2144 configure a field magnetic flux estimator.

[0096] The transfer characteristic unit 2141 receives the first d-axis current command value i d1 * The transfer characteristic unit 2141 receives the d-axis current i d The q-axis current i q The transfer characteristic unit 2141 has a transfer characteristic in which the response of the input first d-axis current command value i d1 * The transfer characteristic is superimposed on the signal and output to the gain 2142.

[0097] The gain 2142 is the d-axis inductance L d and the q-axis inductance L q Difference L d -L q Multiplying by this, the reluctance torque equivalent magnetic flux estimate value φ r ^ is calculated and output to the adder 2145.

[0098] As mentioned above, L d is the d-axis inductance, L q is the q-axis inductance, and a value at a certain representative operating point may be used, or it may be found by referring to map data.

[0099] d-axis current i d and q-axis current i q The reluctance torque generated by n (L d -L q )i d i q Since it is expressed as (L d -L q )i d The term is defined as the equivalent magnetic flux of the reluctance torque. n is the number of pole pairs.

[0100] As shown above, the q-axis current i q The reluctance torque equivalent flux estimate φ r By using ^, the q-axis current i q The second q-axis current command value i q2 * can be calculated.

[0101] The transfer characteristic section 2143 receives the second f-axis current command value i f2 * The transfer characteristic unit 2143 receives the f-axis current i f The q-axis current i q The transfer characteristic unit 2143 has a transfer characteristic in which the response of the input second f-axis current command value i f2 *The transfer characteristic is superimposed on the signal and output to the gain 2144.

[0102] The gain 2144 is the mutual inductance M between the stator and rotor for the output of the transfer characteristic section 2143. f Multiplying by this, the estimated field flux value φ f ^ is calculated and output to the adder 2145. Here, the mutual inductance M f A value at a certain representative operating point may be used, or may be determined by referring to map data.

[0103] As shown above, the q-axis current i q The field flux estimate φ f By using ^, the q-axis current i q The second q-axis current command value i q2 * can be calculated.

[0104] The adder 2145 calculates the reluctance torque equivalent flux estimate φ r The magnetic flux estimated value φf^ is added to generate a magnetic flux estimated value φ^, which is output to the first torque command value calculator 215 (FIG. 8) and the second q-axis current command value calculator 217 (FIG. 8).

[0105] <Vibration damping torque command value calculator 216> 11 is a block diagram of vibration suppression torque command value calculator 216. Vibration suppression torque command value calculator 216 is made up of a feedforward compensator 2161 and a feedback compensator (adder 2162, angular velocity estimator 2163, subtractor 2164, transfer characteristic section 2165).

[0106] The feedforward compensator 2161 receives a first torque command value T m1 * is input to the feedforward compensator 2161. The feedforward compensator 2161 calculates a transfer function (G r (s) / G p The feedforward compensator 2161 has a first torque command value T m1* The transfer function is superimposed on the second torque command value T m2 * and outputs it to the adder 2162 and the angular velocity estimator 2163.

[0107] The adder 2162 calculates the second torque command value T m2 * and the third torque command value T output from the transfer characteristic unit 2165. m3 * The final torque command value T mfin * and outputs this to the second q-axis current command value calculator 217 (FIG. 8).

[0108] The angular velocity estimator 2163 receives a second torque command value T m2 * is input to the angular velocity estimator 2163. The angular velocity estimator 2163 calculates a transfer function (G p The angular velocity estimator 2163 has the second torque command value T m2 * The transfer function is superimposed on the motor 6 to obtain the angular velocity estimate ω rm ^ is generated and output to the subtractor 2164.

[0109] The subtractor 2164 subtracts the estimated angular velocity ω of the motor 6. rm ^ to the mechanical angular velocity ω of motor 6 rm (Measured value) minus the difference (ω rm ^-ω rm ) and outputs it to the transfer characteristic section 2165.

[0110] The transfer characteristic unit 2165 calculates the transfer function (G p The inverse characteristic filter (H(s) / G p (s)). Here, the difference between the denominator order and the numerator order of the transfer function (H(s)) is the transfer function (G p It is set to be equal to or greater than the difference between the denominator order and the numerator order of (s).

[0111] The transfer characteristic unit 2165 calculates the difference (ω rm ^-ω rm ) is filtered by an inverse characteristic filter to obtain the third torque command value T m3 * and outputs it to the adder 2162.

[0112] <Model of the driving force transmission system of an electric vehicle> Fig. 12 is a diagram showing a model of the drive train of the electric vehicle 1. Fig. 13 is a diagram showing the frequency characteristics of the bandpass filter H(s). A model of the electric vehicle 1 to which the present invention is applied will be described.

[0113] Based on FIG. 12, the equations of motion of the electric vehicle 1 are expressed by the following equations (20)-(24).

number

number

number

number

number

[0114] Here, the parameters are as follows:

[0115] J m : Motor inertia J w : Drive shaft inertia (for one shaft) M: Mass of the vehicle K d : Torsional rigidity of the drive shaft K t : Coefficient of friction between the tire and road surface N al :Overall gear ratio r: tire load radius ωm :Motor angular velocity ω w : Drive wheel angular velocity T m :Motor torque T d : Drive shaft torque F: Driving force (for two axes) V: Vehicle speed

[0116] (20)-(24) Laplace transform to torque command value T m from the motor angular velocity ω m The transfer characteristics up to this point are calculated as shown in the following formulas (25) and (26).

number

number

[0117] However, each parameter is as shown in the following formula (27).

number

[0118] Equation (26) is rearranged and expressed as Equation (28) below, where ζ p and ω p are the damping coefficient and natural vibration frequency of the driven torsional vibration system.

number

[0119] Reference Model G m If (s) is expressed by the following equation (29), the linearly approximated vehicle transfer characteristic G p G consisting of the inverse characteristic of (s) and the normative model Gm(s) m (s) / G p A linear filter G with the characteristic (s) inv (s) (transfer function of the feedforward compensator 2161) is expressed by the following equation (30).

number

number

[0120] where ζm and ωm are the damping coefficient and natural vibration frequency of the reference model.

[0121] Next, the transfer function H(s) will be explained. When H(s) is configured as a band-pass filter, it becomes a feedback element that reduces only vibration. In this case, the greatest effect can be obtained by setting the filter characteristics as shown in Figure 13. That is, the transfer function H(s) is set so that the attenuation characteristics on the low-pass side and the high-pass side are approximately the same, and the torsional resonance frequency of the drive system is near the center of the pass band on a logarithmic axis (log scale). And, for example, when H(s) is configured with a first-order high-pass filter and a first-order low-pass filter, the frequency f p is the torsional resonance frequency of the drivetrain, and k is an arbitrary value, and the equation is constructed as shown in Equation (31) below.

number

[0122] where τ L =1 / (2πf HC ), f HC =k f p , τ H =1 / (2πf LC ), f LC =f p / k.

[0123] [Time chart] Figure 14 shows the relationship between the drive shaft torque, drive motor rotation speed, and q-axis current i when the parking lock is released. q , d-axis current i d , f-axis current i f 10 is a time chart showing the response of the control device for the electric vehicle 1 according to the present embodiment, comparing the case where the control is performed by the control device for the electric vehicle 1 according to the present embodiment with the case where the control is not performed by the conventional technology.

[0124] FIG. 14 compares the cases where the control of this embodiment is executed and where it is not executed when the electric vehicle 1 is stopped on a slope with the parking lock and the drive shaft 8 is twisted, and then the brake is applied and the parking lock is released, causing a parking lock release shock (disturbance).

[0125] Before time t1, the electric vehicle 1 is stopped, the shift is set to parking, and the parking lock signal is in the OFF state. At this time, a torque due to torsion is applied to the drive shaft 8. Meanwhile, the d-axis current i d (First d-axis current command value i d1 * ), q-axis current i q (First q-axis current command value i q1 * , the second q-axis current command value i q2 * ), f-axis current i f (First f-axis current command value i f1 * , the second f-axis current command value i f2 * ) are all zero.

[0126] In the prior art that does not implement this embodiment, for example, the second current command value calculator 213 shown in FIG. 8 is omitted, and the first q-axis current command value i q1 * is input, and the first f-axis current command value i is input to the f-axis current control unit 208. f1 * The q-axis current i q , d-axis current i d , f-axis current i f This applies to cases where the following is controlled:

[0127] In the case of the conventional technology, at time t1, the brake is applied and the shift lever is moved from Park to a position other than Park. This causes the park lock signal to switch from OFF to ON. The torsion of the drive shaft 8 is also released, causing a park lock release shock (torsional vibration) in the drive shaft 8. The drive shaft torque [N·m] and rotation speed [rpm] then each produce waveforms that oscillate around zero in accordance with the natural frequency of the torsional vibration of the drive shaft 8.

[0128] On the other hand, the q-axis current i q (First q-axis current command value i q1 * ), d-axis current i d (First d-axis current command value i d1 * ), f-axis current i f (First f-axis current command value i f1 * ) remains zero even after time t1. Therefore, it is not possible to apply drive shaft torque to the drive shaft 8 via the motor 6 (to set it to a value other than zero) in order to reduce the park lock release shock.

[0129] Also, for example, at time t1, the q-axis current i q (First q-axis current command value i q1 * ) is set to a value higher than zero, the f-axis current i f (First f-axis current command value i f1 * ) is zero, it is not possible to apply a drive shaft torque to the drive shaft 8 via the motor 6 to suppress the park lock release shock.

[0130] On the other hand, in this embodiment, the q-axis current i q (Second q-axis current command value i q2 * ), d-axis current i d (First d-axis current command value i d1 * ), f-axis current i f (Second f-axis current command value i f2 *) applies a drive shaft torque to the drive shaft 8 via the motor 6.

[0131] As shown in Figure 14, the q-axis current i q (Second q-axis current command value i q2 * ) and f-axis current i f (Second f-axis current command value i f2 * ) rises when the park lock signal is turned on.

[0132] q-axis current i q (Second q-axis current command value i q2 * ) is a vibration damping torque command value calculator 216 (mechanical angular velocity ω rm The f-axis current i f (Second f-axis current command value i f2 * ) increases so as to rise with a predetermined response characteristic at time t1, and the first f-axis current command value i f1 * The drive shaft torque applied to the motor 6 and the drive shaft 8 is approximately the q-axis current i q and f-axis current i f is proportional to the product of the q-axis current i q and f-axis current i f is not zero immediately after time t1, it is possible to generate drive shaft torque (set to a value other than zero). Therefore, as shown in Figure 14, it is possible to suppress, for example, the park lock release shock that occurs due to the drive shaft torque and the rotation speed [rpm] of the motor 6, and the subsequent torsional vibration.

[0133] In addition, the drive shaft torque, the rotation speed of the motor 6, and the q-axis current i q When a predetermined time has elapsed since all of these have converged within the predetermined threshold, the f-axis current i f (Second f-axis current command value i f2 *) is the first f-axis current command value i f1 * By converging to the same value, unnecessary power consumption is suppressed.

[0134] In FIG. 14, the explanation is given assuming that the parking lock of the electric vehicle 1 stopped on a slope is released. However, for example, when the electric vehicle 1 is traveling at a low speed (f-axis current i f This also applies to the case where the electric vehicle 1 suddenly enters a steep slope in a state where the d-axis current i is extremely small, causing the fluctuation in the rotation speed to exceed a predetermined value (step S301 in FIG. 9). d can also be a constant non-zero value.

[0135] In this embodiment, for example, the first d-axis current command value i output from the first current command value calculator 212 d1 * is input to the second current command value calculator 213, and the second current command value calculator 213 calculates the second d-axis current command value i d2 * and outputs it to the magnetic flux estimator 214, and the magnetic flux estimator 214 calculates the second d-axis current command value i d2 * and the second f-axis current command value i f2 *Based on the first torque command value T m1 * In this case, when there is no disturbance, the second current command value calculator 213 generates the second d-axis current command value i d2 * is the first d-axis current command value i d1 * However, when a disturbance is detected, the second f-axis current command value i f2 * Similarly, the second d-axis current command value i d2 * is the first d-axis current command value i d1 * Alternatively, the absolute value of the signal may be controlled to be higher by a predetermined value than the signal.

[0136] [Effects of this embodiment] According to the control method for the electric vehicle 1 of this embodiment, a field-winding synchronous motor including a rotor having a rotor winding and a stator having a stator winding is used as the drive motor (motor 6), and a motor torque command value T m * is set, and the motor torque command value T m * and a first vertical axis current command value (first d-axis current command value i d1 * ) and a first quadrature axis current command value (first q-axis current command value i q1 * ) and the first f-axis current command value i f1 * and the first vertical axis current command value (first d axis current command value i d1 * ) and the first quadrature axis current command value (the first q-axis current command value i q1 * ) to control the stator current, and the first f-axis current command value i f1 * a control method for an electric vehicle (1) for controlling a rotor current by a first f-axis current command value i when there is no disturbance to a driving force transmission system of the electric vehicle (1), f1 * While the motor torque command value T m * is equal to or less than a predetermined value and a disturbance is detected, the first f-axis current command value i f1 * The second f-axis current command value i f2 * is calculated, and the first vertical axis current command value (first d axis current command value i d1 * ) and the second f-axis current command value i f2 * The magnetic flux estimated value φ^ is estimated based on the first quadrature axis current command value (the first q-axis current command value i q1 * ) and the magnetic flux estimate φ^, the first torque command value T m1 * is calculated, and the first torque command value Tm1 * The vibration suppression torque command value (final torque command value T mfin * ) and calculate the magnetic flux estimation value φ^ and the vibration suppression torque command value (final torque command value T mfin * ) based on the second quadrature axis current command value (second q-axis current command value i q2 * ) is calculated, and the second quadrature axis current command value (the second q axis current command value i q2 * ) and the first vertical axis current command value (the first d axis current command value i d1 * ) and controls the stator current based on the second f-axis current command value i f2 * The rotor current is controlled based on the

[0137] Using the above method, the f-axis current i applied to the rotor winding f (First f-axis current command value i f1 * ) is set small, the f-axis current i f (Second f-axis current command value i f2 * ), it is possible to sufficiently suppress vibrations (for example, shocks and torsional vibrations when the parking lock is released) in the driving force transmission system (mechanism including the drive shaft 8) that may occur due to disturbances.

[0138] In this embodiment, the second f-axis current command value i f2 * is the first f-axis current command value i f1 * and the motor torque command value T m * When the absolute value of is zero, the second f-axis current command value i f2 * This increases the torque in a step function manner, enabling highly accurate suppression of vibrations caused by disturbances in the drivetrain (for example, shocks and torsional vibrations when the parking lock is released).

[0139] In this embodiment, the second f-axis current command value i f2 * is the first f-axis current command value i f1 * and the motor torque command value T m * When the absolute value of is greater than zero and is equal to or less than a predetermined value (for example, 1 [N·m]), the second f-axis current command value i f2 * is increased based on a predetermined response characteristic (for example, equation (18)).

[0140] Motor torque command value T m * is not zero, the second f-axis current command value i f2 * Increasing the second f-axis current command value i f2 * By increasing in accordance with a predetermined response characteristic (for example, equation (18)), the motor torque fluctuation can be suppressed.

[0141] In this embodiment, the disturbance is detected based on shift information that indicates the position of the shift lever of the electric vehicle 1. By detecting the movement of the shift lever operated by the driver from the parking position to a position other than the parking position as the disturbance, it is possible to avoid a delay in control.

[0142] In this embodiment, the disturbance is detected based on fluctuations in the rotation speed of the drive motor (motor 6). This makes it possible to detect disturbances other than the disturbance of the parking lock release, such as a disturbance caused by the electric vehicle 1 suddenly entering a steep slope.

[0143] In this embodiment, the vertical axis is the d-axis of the rotor, and the horizontal axis is the q-axis of the rotor, which makes it possible to more reliably generate torque for suppressing vibration in the drive motor (motor 6).

[0144] In this embodiment, the second f-axis current command value i f2 * is the first f-axis current command value i f1 * The specified time for the q-axis current i q This allows the second f-axis current command value i f2 * is the first f-axis current command value i f1 * Since it is possible to set the time (prescribed time) for which the voltage becomes higher than the reference voltage, vibration can be more reliably suppressed.

[0145] In this embodiment, the second f-axis current command value i f2 * is the first f-axis current command value i f1 * This allows the second f-axis current command value i to be calculated with a simple configuration. f2 * is the first f-axis current command value i f1 * You can set the time for the temperature to rise above 100°C.

[0146] In this embodiment, the second f-axis current command value i f2 * is the first f-axis current command value i f1 * The rotation speed of the drive motor (motor 6) becomes higher than the specified time. of This allows the second f-axis current command value i f2 * is the first f-axis current command value i f1 * Since it is possible to set the time (prescribed time) for which the voltage becomes higher than the reference voltage, vibration can be more reliably suppressed.

[0147] In this embodiment, the motor torque command value T m * When exceeds a predetermined value (for example, 1 [N·m]), the second f-axis current command value i f2* is the first f-axis current command value i f1 * or the second f-axis current command value i f2 * is passed through a predetermined response characteristic (for example, equation (19)) to obtain the first f-axis current command value i f1 * At this time, the first f-axis current command value i f1 * has a predetermined magnitude, and the electric motor (motor 6) is in a state where it can generate a predetermined torque. Therefore, the second f-axis current command value i f2 * is the first f-axis current command value i f1 * Since it is possible to suppress shock to the driving force transmission system due to disturbance without setting the vehicle speed higher than the reference speed, it is possible to reduce power consumption accordingly.

[0148] In this embodiment, if the vehicle speed V of the electric vehicle 1 exceeds a predetermined value (for example, 5 m / s) within a specified time, the second f-axis current command value i f2 * is the first f-axis current command value i f1 * or the second f-axis current command value i f2 * is passed through a predetermined response characteristic (for example, equation (19)) to obtain the first f-axis current command value i f1 * As a result, if the absolute value of the vehicle speed V exceeds a predetermined value (for example, 5 [m / s]) even before the specified time has elapsed, it can be determined that the shock has subsided, and the second f-axis current command value i f2 * The first f-axis current command value i f1 * By matching the

[0149] If the brake of the electric vehicle 1 changes from the on state to the off state within the specified time, the second f-axis current command value i f2 * is the first f-axis current command value i f1* or the second f-axis current command value i f2 * is converted into the first f-axis current command value i via a predetermined response characteristic (for example, equation (19)). f1 * As a result, if the brake transitions from ON to OFF even before the specified time has elapsed, it can be determined that the shock caused by the disturbance has converged, and the second f-axis current command value i f2 * The first f-axis current command value i f1 * By matching the

[0150] Furthermore, according to the control device (motor controller 2) of the electric vehicle 1 of this embodiment, the electric vehicle 1 is controlled using a field-winding type synchronous motor having a rotor with rotor windings and a stator with stator windings as a drive motor (motor 6), and the motor torque command value T m * a motor torque command value setting means (motor controller 2) for setting the motor torque command value T m * and a first vertical axis current command value (first d-axis current command value i d1 * ) and the first quadrature axis current command value (first q-axis current command value i q1 * ) and the first f-axis current command value i f1 * and a first current command value calculation means (first current command value calculator 212) that calculates the first vertical axis current command value (first d axis current command value i d1 * ) and the first quadrature axis current command value (the first q-axis current command value i q1 * ) to control the stator current, and the first f-axis current command value i f1 *and a current control unit (motor controller 2) for controlling a rotor current by a first f-axis current command value i when there is no disturbance to the driving force transmission system of the electric vehicle 1. f1 * While the motor torque command value T m * is equal to or less than a predetermined value and a disturbance is detected, the first f-axis current command value i f1 * The second f-axis current command value i f2 * a second current command value calculation means (second current command value calculator 213) that calculates the first vertical axis current command value (first d axis current command value i d1 * ) and the second f-axis current command value i f2 * a magnetic flux estimator 214 for estimating a magnetic flux estimated value φ^ based on a first quadrature axis current command value (a first q-axis current command value i q1 * ) and the magnetic flux estimate φ^, the first torque command value T m1 * a torque command value calculation means (first torque command value calculator 215) for calculating the first torque command value T m1 * The vibration suppression torque command value (final torque command value T mfin * ) and the vibration-damping torque command value calculation means (vibration-damping torque command value calculator 216) that calculates the magnetic flux estimated value φ^ and the vibration-damping torque command value (final torque command value T mfin * ) based on the second quadrature axis current command value (second q-axis current command value i q2 * and a third current command value calculation unit (second q-axis current command value calculator 217) that calculates the second quadrature axis current command value (second q-axis current command value i q2 * ) and the first vertical axis current command value (the first d axis current command value id1 * ) and controls the stator current based on the second f-axis current command value i f2 * The rotor current is controlled based on the

[0151] With the above configuration, the f-axis current i applied to the rotor winding f (First f-axis current command value i f1 * ) is set small, the f-axis current i f (Second f-axis current command value i f2 * ), it is possible to sufficiently suppress vibrations (for example, shocks and torsional vibrations when the parking lock is released) in the driving force transmission system (mechanism including the drive shaft 8) that may occur due to disturbances.

[0152] Although the embodiments of the present invention have been described above, the above embodiments merely illustrate some of the application examples of the present invention, and the technical scope of the present invention is not intended to be limited to the specific configurations of the above embodiments. Furthermore, the above embodiments can be combined as appropriate. [Explanation of symbols]

[0153] 1 Electric vehicle, 2 Motor controller, 6 Motor, 206 Q-axis current control unit, 207 D-axis current control unit, 208 F-axis current control unit, 212 First current command value calculator, 213 Second current command value calculator, 214 Magnetic flux estimator, 215 First torque command value calculator, 216 Damping torque command value calculator, 217 Second q-axis current command value calculator

Claims

1. a first vertical-axis current command value that is a vertical-axis command value of an orthogonal component of a stator current, a first quadrature-axis current command value that is a quadrature-axis command value of the stator current, and a first f-axis current command value that is a rotor current command value, based on the motor torque command value and the vehicle information; and a first vertical-axis current command value that is a vertical-axis command value of an orthogonal component of a stator current, and a first f-axis current command value that is a rotor current command value, the stator current being controlled by the first vertical-axis current command value and the first quadrature-axis current command value, and the rotor current being controlled by the first f-axis current command value, calculating a second f-axis current command value that is the same as the first f-axis current command value when there is no disturbance to a driving force transmission system of an electric vehicle, and that is higher than the first f-axis current command value when the absolute value of the motor torque command value is equal to or less than a predetermined value and the disturbance is detected; estimating a magnetic flux estimation value based on the first vertical axis current command value and the second f-axis current command value; calculating a first torque command value based on the first quadrature axis current command value and the magnetic flux estimation value; calculating a vibration-damping torque command value by performing a calculation process on the first torque command value to suppress vibrations in the driving force transmission system; calculating a second quadrature axis current command value based on the magnetic flux estimation value and the vibration suppression torque command value; A control method for an electric vehicle, comprising: controlling the stator current based on the second quadrature-axis current command value and the first vertical-axis current command value; and controlling the rotor current based on the second f-axis current command value.

2. 2. The control method for an electric vehicle according to claim 1, wherein, when the second f-axis current command value before detecting the disturbance matches the first f-axis current command value and the absolute value of the motor torque command value when detecting the disturbance is zero, the second f-axis current command value is increased in a step function manner.

3. 2. The control method for an electric vehicle according to claim 1, wherein, when the second f-axis current command value before the disturbance is detected matches the first f-axis current command value and the absolute value of the motor torque command value when the disturbance is detected is greater than zero and equal to or less than the predetermined value, the second f-axis current command value is increased based on a predetermined response characteristic.

4. The method for controlling an electric vehicle according to any one of claims 1 to 3, wherein the disturbance is detected based on shift information representing a position of a shift lever of the electric vehicle.

5. 4. The method for controlling an electric vehicle according to claim 1, wherein the disturbance is detected based on a fluctuation in the rotation speed of the drive motor.

6. The method for controlling an electric vehicle according to any one of claims 1 to 5, wherein the vertical axis is a d-axis of the rotor, and the horizontal axis is a q-axis of the rotor.

7. 7. The method for controlling an electric vehicle according to claim 6, wherein the specified time during which the second f-axis current command value becomes higher than the first f-axis current command value is set based on a fluctuation range of the q-axis current.

8. 6. The method for controlling an electric vehicle according to claim 1, wherein the specified time during which the second f-axis current command value becomes higher than the first f-axis current command value is set to a predetermined time.

9. 5. The method for controlling an electric vehicle according to claim 1, wherein the specified time during which the second f-axis current command value becomes higher than the first f-axis current command value is set based on a fluctuation range of the rotation speed of the drive motor.

10. 10. The method for controlling an electric vehicle according to claim 7, wherein, when the motor torque command value exceeds a predetermined value within the specified time, the second f-axis current command value is made to coincide with the first f-axis current command value in a step function manner, regardless of the specified time, or the second f-axis current command value is made to converge to the first f-axis current command value after passing through a predetermined response characteristic.

11. 10. The method for controlling an electric vehicle according to claim 7, wherein, when a vehicle speed of the electric vehicle exceeds a predetermined value within the specified time, the second f-axis current command value is made to coincide with the first f-axis current command value in a step function manner, regardless of the specified time, or the second f-axis current command value is made to converge to the first f-axis current command value after passing through a predetermined response characteristic.

12. 10. The method for controlling an electric vehicle according to claim 7, wherein, when a brake of the electric vehicle is changed from an on state to an off state within the specified time, the second f-axis current command value is made to coincide with the first f-axis current command value in a step function manner, regardless of the specified time, or the second f-axis current command value is made to converge to the first f-axis current command value via a predetermined response characteristic.

13. The control target is an electric vehicle using a field-winding type synchronous motor as a drive motor, the field-winding type synchronous motor including a rotor having a rotor winding and a stator having a stator winding, a motor torque command value setting means for setting a motor torque command value based on vehicle information; a first current command value calculation means for calculating a first vertical axis current command value which is a vertical axis command value of an orthogonal component of a stator current, a first quadrature axis current command value which is a quadrature axis command value of the stator current, and a first f-axis current command value which is a rotor current command value, based on the motor torque command value and the vehicle information; a current control unit that controls the stator current based on the first vertical axis current command value and the first quadrature axis current command value, and controls the rotor current based on the first f-axis current command value, a second current command value calculation means for calculating a second f-axis current command value that is the same as the first f-axis current command value when there is no disturbance to a driving force transmission system of an electric vehicle, and that is higher than the first f-axis current command value when the absolute value of the motor torque command value is equal to or less than a predetermined value and the disturbance is detected; a magnetic flux estimation means for estimating a magnetic flux estimated value based on the first vertical axis current command value and the second f-axis current command value; a torque command value calculation means for calculating a first torque command value based on the first quadrature axis current command value and the magnetic flux estimation value; a vibration-damping torque command value calculation means for calculating a vibration-damping torque command value by performing a calculation process on the first torque command value to suppress vibrations in the driving force transmission system; a third current command value calculation means for calculating a second quadrature axis current command value based on the magnetic flux estimation value and the vibration suppression torque command value, the current control means controls the stator current based on the second quadrature-axis current command value and the first vertical-axis current command value, and controls the rotor current based on the second f-axis current command value.

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