JP7735871B2 - Electric vehicle control method and electric vehicle control device - Google Patents

Description

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

Patent Document 1 discloses an electric vehicle control method for an electric vehicle equipped with multiple magnet-type synchronous motors as drive sources. The method performs torque correction processing (vibration suppression control calculation) to remove vibration components from the drive force transmission system from each target torque command value determined based on factors such as the amount of accelerator pedal operation by the driver, by referencing the motor angular velocity, which indicates the rotational state of each drive motor.

Japanese Patent Application Laid-Open No. 2019-103249

However, in electric vehicles equipped with multiple drive motors, communication delays between the motor controllers that control each drive motor can affect the accuracy of the torque correction process, which calculates each correction torque command value from each target torque command value, such as vibration control calculations, resulting in torque response delays and making it impossible to achieve the intended behavior of the electric vehicle. In particular, when electric vehicles use electric motors such as wound-field synchronous motors and induction motors, which have characteristics that result in a greater torque response delay than permanent magnet synchronous motors, the accuracy of the torque correction process is further reduced.

Therefore, an object of the present invention is to provide an electric vehicle control method and an electric vehicle control device that can achieve torque response that matches the intended behavior of an electric vehicle equipped with multiple drive motors.

One aspect of the present invention provides an electric vehicle control method for controlling multiple drive motors in an electric vehicle equipped with multiple drive motors based on a current command value set for each drive motor. In this electric vehicle control method, each motor controller controlling each drive motor executes an estimated torque calculation process to calculate an estimated torque based on a target torque command value set for each drive motor and the response characteristics of each drive motor. The first estimated torque calculated by one motor controller is output to another motor controller. The first motor controller executes a torque command value correction process and a current command value calculation process using a second estimated torque calculated by the other motor controller as input. In particular, the torque command value correction process calculates a corrected torque command value by correcting the target torque command value for the first drive motor with reference to the rotational state of the first drive motor controlled by the one motor controller, the rotational state of the second drive motor controlled by the other motor controller, and the second estimated torque. Furthermore, the current command value calculation process calculates a current command value for the first drive motor from the corrected torque command value.

The present invention makes it possible to achieve torque response that matches the intended behavior of an electric vehicle equipped with multiple drive motors.

FIG. 1 is a block diagram showing the main configuration of an electric vehicle in which an electric vehicle control method according to a first embodiment is executed. FIG. 2 is a flowchart showing the processing by the vehicle controller. FIG. 3 is a diagram showing an example of an accelerator opening-torque table. FIG. 4 is a flowchart showing the processing by the front/rear motor controller. FIG. 5 is a block diagram showing the configuration of the F motor controller according to the first embodiment. FIG. 6 is a diagram showing a model of a driving force transmission system of an electric vehicle (4WD). FIG. 7 is a block diagram showing the configuration of the front vibration damping control calculation unit. FIG. 8 is a block diagram showing the configuration of the rear motor controller according to the first embodiment. FIG. 9 is a block diagram showing the configuration of the rear estimated torque calculation unit. FIG. 10 is a block diagram showing the configuration of the rear vibration damping control calculation unit. FIG. 11 is a block diagram showing the main configuration of an electric vehicle in which an electric vehicle control method according to the second embodiment is executed. FIG. 12 is a block diagram showing the configuration of the F motor controller according to the second embodiment. FIG. 13 is a diagram showing a model of a driving force transmission system with only one driving wheel. FIG. 14 is a block diagram showing the configuration of the front vibration damping control calculation unit. FIG. 15 is a block diagram showing the configuration of the front F/F compensation calculation unit. FIG. 16 is a block diagram showing the configuration of a vehicle model (front). FIG. 17 is a block diagram showing the configuration of the right rear motor controller according to the second embodiment. FIG. 18 is a block diagram showing the configuration of the right rear estimated torque calculation unit. FIG. 19 is a block diagram showing the configuration of the right rear vibration damping control calculation unit. FIG. 20 is a block diagram showing the configuration of the left rear motor controller according to the second embodiment. FIG. 21 is a block diagram showing the main configuration of an electric vehicle in which an electric vehicle control method according to the third embodiment is executed. FIG. 22 is a block diagram showing the configuration of a right F motor controller according to the third embodiment. FIG. 23 is a block diagram showing the configuration of the left F motor controller according to the third embodiment. FIG. 24 is a block diagram showing the configuration of the right front vibration damping control calculation unit. FIG. 25 is a block diagram showing the configuration of the left front vibration damping control calculation unit. FIG. 26 is a block diagram showing the configuration of a vehicle model (front left and front right). FIG. 27 is a block diagram showing the configuration of a right rear motor controller according to the third embodiment. FIG. 28 is a block diagram showing the configuration of the left rear motor controller according to the third embodiment. FIG. 29 is a block diagram showing the configuration of the right rear vibration damping control calculation unit. FIG. 30 is a block diagram showing the configuration of the left rear vibration damping control calculation unit. FIG. 31 is a timing chart showing the control results of Example 1 and Comparative Example 1. FIG. 32 is a timing chart showing the control results of Example 2 and Comparative Example 2. FIG. 33 is a timing chart showing the control results of Example 3 and Comparative Example 3.

The electric vehicle control method of each embodiment of the present invention will be described below with reference to the drawings. Note that, for simplicity of description, in each of the following embodiments, the initial letters "F," "R," "FR," "FL," "RR," and "RL" are used to appropriately distinguish between the front, rear, right front, left front, right rear, and left rear elements of the vehicle with respect to the configuration and control parameters of the vehicle on which the electric vehicle control method is executed.

[First embodiment]
1 is a block diagram showing the main configuration of an electric vehicle 100 in which an electric vehicle control method is executed. In this embodiment, the electric vehicle 100 refers to a vehicle such as an electric vehicle (EV) or hybrid electric vehicle (HEV) equipped with a drive motor 4 consisting of one or more electric motors as a driving source for traveling. In particular, the electric vehicle 100 of this embodiment is equipped with a front drive system Sf including a drive motor 4 (F drive motor 4f) that provides drive force to _front drive wheels 9fR, 9fL, and a rear drive system Sr including a drive motor 4 (R drive motor 4r) that provides drive force to rear drive wheels 9rR, _9rL .

In addition, in this embodiment, the F drive motor 4f is configured as an interior permanent magnet synchronous motor (IPMSM), and the R drive motor 4r is configured as an electrically excited synchronous motor (EESM).

Battery 1 is composed of an on-board secondary battery that supplies (discharges) drive power to each drive motor 4 during power running and receives (charges) regenerative power during regenerative running.

The vehicle controller 30 receives the vehicle speed V and the accelerator opening APO as digital signals, calculates the target torque command value _Tm ^* (F target torque command value _Tmf ^* and R target torque command value _Tmr ^* ) for each drive motor 4, and transmits them to each motor controller 31 (F motor controller 31f and R motor controller 31r) using a predetermined in-vehicle communication protocol (such as CAN communication). In other words, each target torque command value _Tm ^* is a torque value equivalent to the required output for each drive motor 4.

Each motor controller 31 receives, as digital signals, signals indicating various vehicle variables such as each target torque command value _Tm ^* , the rotor phase α of each drive motor 4 (F rotor phase _αf and R rotor phase _αr ), and the motor current i (F motor current _if and R motor current _ir ) that is the current flowing through each drive motor 4, and generates PWM signals for controlling each drive motor 4 based on these signals. Furthermore, each motor controller 31 generates drive signals for each inverter 3 (F inverter 3f and R inverter 3r) according to the generated PWM signals.

The F inverter 3f is composed of two pairs of switching elements (e.g., power semiconductor elements such as IGBTs and MOS-FETs) for each phase to control the stator current. By turning the switching elements ON/OFF in response to a drive signal, it converts the DC current supplied from the battery 1 to AC and inversely converts it, thereby passing the desired current through the F drive motor 4f. In addition to the switching elements for stator current control, the R inverter 3r has two pairs (four in total) of switching elements (e.g., power semiconductor elements such as IGBTs and MOS-FETs) connected to each end of the rotor winding to control the rotor current. By turning the switching elements ON/OFF in response to a drive signal, it passes the desired current from the battery 1 through the rotor winding of the R drive motor 4r. Note that if the current flowing through the rotor winding is unidirectional, the two diagonally opposite switching elements of the two pairs of switching elements may be replaced with diodes.

Each drive motor 4 generates driving force using AC current supplied from each inverter 3, and transmits the driving force to each drive wheel 9 via a driving force transmission system consisting of each reducer 5 (F reducer 5f and R reducer 5r) and each drive shaft Ds (F drive shaft Dsf and R drive shaft Dsr). Each drive motor 4 also recovers, as electrical energy, kinetic energy based on the regenerative braking force received from each drive wheel 9 while the vehicle is running. In this case, each inverter 3 converts the AC current generated during regenerative operation of each drive motor 4 into DC current and supplies it to the battery 1. In particular, in this embodiment, the F drive motor 4f supplies driving force to the FR drive wheel 9fR and FL drive wheel 9fL, and the R drive motor 4r supplies driving force to the RR drive wheel 9rR and RL drive wheel 9rL.

Each current sensor 20 (F current sensor 20f and R current sensor 20r) detects each motor current i (particularly F three-phase AC currents _iuf , _ivf , _iwf and R three-phase AC currents _iur , _ivr , _iwr ). However, since the sum of the three-phase AC currents _iu , _iv , _iw is zero, the currents of any two phases may be detected and the current of the remaining phase may be calculated.

The rotation sensors 21 (F rotation sensor 21f and R rotation sensor 21r) are, for example, resolvers or encoders, and detect the rotor phase α of each drive motor 4.

Next, we will explain the processes executed by the vehicle controller 30 and each motor controller 31.

Figure 2 is a flowchart illustrating the processing executed by the vehicle controller 30. The processing relating to steps S201 to S203 shown in Figure 2 is repeatedly executed at a predetermined calculation interval.

In the input process of step S201, the vehicle speed V and the accelerator pedal position APO are input as digital signals. The vehicle speed V (km/h) is acquired via communication from another controller, such as a meter or a brake controller. The vehicle controller 30 may obtain the vehicle speed v (m/s) by multiplying the motor angular velocity _ωm , which is the mechanical angular velocity of the drive motor 4, by the tire dynamic radius r and dividing the result by the gear ratio of the final gear, and then multiplying this by 3600/1000 for unit conversion to calculate the vehicle speed V (km/h). The accelerator pedal position APO (%) is acquired from an accelerator pedal position sensor (not shown) or via communication from another controller, such as a vehicle controller (not shown).

In the target torque command value calculation process in step S202, the accelerator opening-torque table shown in FIG. 3 is referenced to calculate the target torque command values T _mf ^* and T _mr ^* from the vehicle speed V and accelerator opening APO.

In the output process of step S203, the calculated target torque command values T _mf ^* and T _mr ^* are output to the respective motor controllers (F motor controller 31f and R motor controller 31r) via communication.

Figure 4 is a flowchart explaining the processing executed by each motor controller 31. The processing relating to steps S401 to S405 shown in Figure 4 is repeatedly executed at a predetermined calculation cycle.

In the input process of step S401, the rotor phase α (rad) of the drive motor 4, which is the control target, the motor rotation speed N _m (rpm), the motor current i (A), the DC voltage value V _dc (V) of the battery 1, and the target torque command value T _m ^* are input as digital signals.

The rotor phase α (rad) is obtained from the detection value of the rotation sensor 21. The motor rotation speed N _m (rpm) is obtained by performing a predetermined calculation on the rotor phase α (rad). Specifically, first, the rotor electrical angular speed _ωe of the drive motor 4 is calculated by differentiating the rotor phase α. Then, the rotor electrical angular speed _ωe is divided by the number p of pole pairs of the drive motor 4 to calculate the motor angular speed ω _m (rad/s), which is a mechanical angular speed. Furthermore, the motor angular speed ω _m is multiplied by a unit conversion coefficient (60/2π) to obtain the motor rotation speed N _m (rpm).

As described above, the motor current i (A) is obtained from the current sensor 20. The DC voltage value V _dc (V) is detected by a voltage sensor (not shown) provided on the DC power supply line between the battery 1 and the inverter 3. Note that the power supply voltage value obtained by a battery controller (not shown) may also be obtained as the DC voltage value V _dc (V).

The target torque command value T _m ^* is acquired from the vehicle controller 30 via communication.

In the estimated torque calculation process in step S402, the estimated torque ^ _m is calculated based on the target torque command value T _m ^* , motor angular velocity ω _m , and DC voltage value V _dc , which are the control targets of the motor itself.

In the vibration suppression control calculation process of step S403, the motor angular velocity _ωm is used as an input, and a correction calculation is performed to suppress vibrations in the driving force transmission system (such as torsional vibrations of the drive shaft Ds) for the target torque command value _Tm ^* or the estimated torque _TM , thereby calculating a third torque command value _Tm3 .

In the current command value calculation process of step S404, the current command value i ^* is calculated based on the third torque command value _Tm3 calculated in the vibration suppression control calculation process.

Details of the estimated torque calculation process, vibration suppression control calculation process, and current command value calculation process will be described later.

In the current control calculation process of step S405, the F motor controller 31f performs coordinate transformation on the F motor current i _f , particularly the F three-phase current values (i _uf , i _vf , i _wf ), using the F rotor phase α _f to calculate the F-dq-axis current values (i _df , i _qf ). The F motor controller 31f also calculates the F-dq-axis voltage command values (v _df , v _qf ) as the current command value ^v for the F drive motor 4f from the deviation between the F-dq-axis current command values (i _df ^* , i _qf ^* ), which are the current command value i* for the F drive motor 4f, and the F-dq-axis current values (i _df , i _qf ). Note that non-interference control may be performed as appropriate in this calculation.

Furthermore, the F motor controller 31f performs coordinate transformation on the F-dq-axis voltage command values (v _df , v _qf ) using the F rotor phase α _f to calculate the F three-phase voltage command values (v _uf , v _vf , v _wf ).The F motor controller 31f then determines the F-PWM signal (t _uf , t _vf , t _wf ) [%] for driving the F inverter 3f based on the determined F three-phase voltage command values (v _uf , v _vf , v _wf ) and the DC voltage value V _dc.The F-PWM signal determined in this manner opens and closes the switching elements of the F inverter 3f, allowing the F drive motor 4f to be driven with the desired torque.

On the other hand, the R motor controller 31r performs coordinate transformation on the R three-phase current values (i _ur , i _vr , i _wr ) using the R rotor phase α _r to calculate the R dq-axis current values (i _dr , i _qr ). The R motor controller 31r also acquires the R f-axis current value i _fr which corresponds to the detected value of the field current (f-axis current) of the R drive motor 4r. Furthermore, the R motor controller 31r calculates R-dq-axis voltage command values ( _vdr , _vqr ) and R-f-axis voltage command value _vfr ^* as the current command value ^v for the R drive motor 4r from the deviations between the R- _dq -axis current command values (iqf ^* , _iqr ^* ) and R-f-axis current command value _ifr ^* , which are the current command value i* for the R drive motor 4r, and the R-dq-axis current values ( _idr , _iqr ) and R-f-axis current value _ifr . Note that non-interference control may be performed as appropriate in this calculation.

Furthermore, the R motor controller 31r performs coordinate transformation on the R-dq-axis voltage command values (v _dr , v _qr ) using the R rotor phase α _r to calculate the R three-phase voltage command values (v _ur , v _vr , v _wr ).The R motor controller 31r then determines the R-PWM signal (t _ur , t _vr , t _wr ) [%] for driving the R inverter 3r based on the R three-phase voltage command values ₍ v _ur , v _vr , v _wr ), the R-f-axis voltage command value v _fr ^* , and the DC voltage value V dc.The R-PWM signal thus determined opens and closes the switching elements of the R inverter 3r, allowing the R drive motor 4r to be driven with the desired torque.

Next, we will explain in detail the estimated torque calculation process, vibration suppression control calculation process, and current command value calculation process in the F motor controller 31f and R motor controller 31r.

<I.F motor controller>
5 is a block diagram showing the control configuration of the F motor controller 31f. As shown in the figure, the F motor controller 31f has an estimated torque calculation unit 501 that executes an F estimated torque calculation process, a vibration suppression control calculation unit 502 that executes an F vibration suppression control calculation process, and a current command value calculation unit 503 that executes an F current command value calculation process.

I-1. F Estimated Torque Calculation Process The estimated torque calculation unit 501 calculates the F estimated torque T^ _mf using the following equation (1).
In the equation, "τ _m " represents the dq axis current response time constant of the F drive motor 4f.

I-2. F Vibration Suppression Control Calculation Processing Vibration suppression control calculation unit 502 uses a model of the 4WD driving force transmission system of electric vehicle 100 to execute corrections to suppress vibrations in the driving force transmission system.

Figure 6 shows a model of the driving force transmission system of the electric vehicle 100. The definitions of each parameter, including those already explained, are shown below.

_Jmf , _Jmr : Motor inertia _Jwf , _Jwr : Drive wheel inertia (for one axle)
K _df , K _dr : Torsional rigidity of drive shaft K _tf , K _tr : Coefficient of friction between tire and road surface N _f , N _r : Overall gear ratio r _f , r _r : Tire load radius ω _mf , ω _mr : Motor angular velocity ω^ _mf , ω^ _mr : Motor angular velocity estimate θ _mf , θ _mr : Motor angle ω _wf , ω _wr : Drive wheel angular velocity θ _wf , θ _wr : Drive wheel angle T _mf , T _mr : Motor torque T _df , T _dr : Drive shaft torque F _f , F _r : Driving force (for two shafts)
θ _df , θ _dr : torsional angle of drive shaft ω _df , ω _dr : torsional angular velocity of drive shaft V: vehicle speed M: vehicle weight

Referring to FIG. 6, the equations of motion of the 4WD electric vehicle 100 are expressed by the following equations (2) to (12).

By performing Laplace transformation on the above equations (2) to (12), the transfer characteristics from the F motor torque T _mf to the F motor angular velocity ω _mf are expressed by the following equation (13).
However, the coefficients in equation (13) are expressed by the following equations (14) to (17), respectively.

Furthermore, by examining the poles and zeros of the transfer function of equation (13), the following equation (18) is obtained.

In equation (18), α and α', β and β', ζpr and ζpr', and ωpr and ωpr' are very close values, so pole-zero cancellation (approximation: α=α', β=β', ζpr=ζpr', ωpr=ωpr') is performed to form the (second-order)/(third-order) transfer characteristic G _p (s) shown in the following equation (19).

As a result, when the transfer characteristics from the F motor torque T _mf to the F motor angular velocity ω _mf are examined using a 4WD vehicle model, G _p (s) can be approximated by a quadratic/cubic equation. Here, the reference response that suppresses front torsional vibration caused by the driving force transmission system is given by the following equation (20).

Then, the feedforward compensation calculation unit (F/F compensation calculation unit) that suppresses the torsional vibration of the front is expressed by the following equation (21).

Using the same calculation logic as above, the transfer characteristic from the R motor torque T _mr to the R motor angular velocity ω _mr is expressed by the following equation (22).

Here, the reference response for suppressing rear torsional vibration caused by the driving force transmission system is given by the following equation (23).

Then, the feedforward compensation calculation unit (F/F compensation calculation unit) that suppresses rear torsional vibration is expressed by the following equation (24).

Next, the transfer characteristics from the R motor torque T _mr to the F motor angular velocity ω _mf will be explained. By performing a Laplace transform on the above equations (2) to (12), the transfer characteristics from the R motor torque T _mr to the F motor angular velocity ω _mf can be expressed by the following equation (25).

Furthermore, by examining the poles and zeros of the transfer function of equation (25), the following equation (26) is obtained.

In equation (26), the poles α and β are both located far from the origin and the dominant pole, so they have little effect on the transfer characteristics of G _prf (s). Therefore, the transfer function G _prf (s) can be approximately expressed by the following equation (27).

Furthermore, when the rear vibration damping control algorithm is taken into consideration in the vehicle model G _prf (s), the transfer function of the following equation (28) is obtained.

Next, in order to suppress the torsional vibration of the front from the reference response of the F motor angular velocity estimated value ω^ _mf , the transfer function of the following equation (29) is determined.

Similarly, when the transfer characteristic from the F motor torque T _mf to the R motor angular velocity ω^ _mr is calculated, the following equation (30) is obtained.

In equation (30), the poles α and β are both located far from the origin and the dominant pole, so they have little effect on the transfer characteristics of G _pfr (s). Therefore, the transfer function G _pfr (s) can be approximately expressed by the following equation (31).

Furthermore, in order to suppress the torsional vibration of the front from the reference response of the F motor angular velocity estimated value ω^ _mf , the transfer function of the above equation (29) is determined. Then, when the front vibration suppression control algorithm is taken into account in the vehicle model G _pfr (s), the transfer function of the following equation (32) is obtained.

Next, in order to suppress rear torsional vibration from the reference response of the R motor angular velocity estimated value ω^ _mr , the transfer function of the following equation (33) is determined.

Figure 7 is a block diagram showing the configuration of the vibration suppression control calculation unit 502. As shown in the figure, the vibration suppression control calculation unit 502 has an F/F compensation calculation unit 701, a first delay correction unit 702, a pre-correction motor angular velocity estimation unit 703, a corrected motor angular velocity estimation unit 704, a second delay correction unit 705, and an F/B compensation calculation unit 706.

The F/F compensation calculation unit 701 receives the F target torque command value T _mf ^* as input, executes the F/F compensation process expressed by the above equation (21), and calculates the F first torque command value T _mf1 .

In order to take into account the influence of the communication delay T1 [s] on the R estimated torque T^ _mr caused by communication between the vehicle controller 30, the F motor controller 31f, and the R motor controller 31r, the first delay correction unit 702 performs processing defined by the following equation (34) on the F target torque command value T _mf ^* to calculate the F target torque command value delay correction value T' _mf .

The pre-correction motor angular velocity estimator 703 receives the F target torque command value delay correction value _T'mf as an input, and calculates the pre-correction F motor angular velocity estimate value using the transfer characteristic _Grr (s) expressed by the above equation (23).

The corrected motor angular velocity estimator 704 receives the R estimated torque Tr _mr as input and calculates a corrected F motor angular velocity estimate value using the transfer characteristic G _rrf (s) expressed by the above equation (29).

In order to take into account the influence of the communication delay T1 [s] on the R estimated torque T^ _mr , the second delay correction unit 705 performs processing defined by the following equation (35) on the F motor angular velocity detection value ω _mf to calculate the F motor angular velocity delay correction value ω' _mf .
However, "T2" in the formula represents the delay time [s] due to the control calculation.

The F/B compensation calculation unit 706 subtracts the F motor angular velocity delay correction value ω' _mf from the F motor angular velocity estimated value ω^ _mf , and applies a band-pass filter H _f (s) to the resultant value and the inverse system of the transfer characteristic G _p (s) shown in the above equation (19), thereby calculating the F second torque command value T _mf2 .

The band-pass filter _Hf (s) is set so that the attenuation characteristics of the low-pass side and the high-pass side are approximately the same and the torsional resonance frequency of the drivetrain is near the center of the pass band on a logarithmic axis (log scale). For example, when the band-pass filter _Hf (s) is composed of a first-order high-pass filter and a first-order low-pass filter, the band-pass filter _Hf (s) is configured as shown in the following equation (36).
where τ _Hf = 1/(2πf _HCf ), f _HCf = k _f · f _pf , τ _Lf = 1/(2πf _LCf ), f _LCf = f _pf /k _f , where frequency f _pf is the torsional resonance frequency of the F drive system S _f , and k _f is an arbitrary value that constitutes a band pass.

Then, the vibration suppression control calculation unit 502 calculates the F third torque command value T _mf2 by taking the sum of the F first torque command value T _mf1 and the F second torque command value T _mf2 , and outputs the F third torque command value T mf2 to the current command value calculation unit 503 shown in FIG.

I-3. F current command value calculation process Current command value calculation unit 503 shown in Fig. 5 calculates F dq axis current command values (i df *, i qf *) by referring to a table stored in advance in a predetermined storage area, based on F third torque command value T _mf3 , F motor angular velocity detected value _{ω mf} , and DC voltage value _{V dc} calculated by ^vibration suppression control calculation ^unit 502.

<II. R motor controller>
8 is a block diagram showing the control configuration of the R motor controller 31r. As shown in the figure, the R motor controller 31r has a first current command value calculation unit 801 that executes R first current command value calculation processing, an estimated torque calculation unit 802 that executes R estimated torque calculation processing, a vibration suppression control calculation unit 803 that executes R vibration suppression control calculation processing, and a second current command value calculation unit 804 that executes R second current command value calculation processing.

II-1. R First Current Command Value Calculation Processing The first current command value calculation unit 801 receives the R target torque command value T _mr ^* , the R motor angular velocity detection value ω _mr , and the DC voltage value V _dc as input, and calculates the R first dq-axis current command values (i _dr1 ^* , i _qr1 ^* ) and the R first f-axis current command value i _fr1 ^* by referring to a table stored in advance in a predetermined storage area.

II-2. R Estimated Torque Calculation Processing Fig. 9 is a block diagram showing the configuration of the estimated torque calculation unit 802. As shown in the figure, the estimated torque calculation unit 802 has a reluctance torque equivalent magnetic flux estimation unit 901, a field magnetic flux estimation unit 902, and a torque calculation unit 903.

The reluctance torque equivalent magnetic flux estimator 901 receives the R first d-axis current command value i _dr1 ^* as an input and calculates a reluctance torque equivalent magnetic flux estimate value φ^ _r according to the following equation (37).
In the formula, "τ _d " and "τ _q " represent the response time constant of the d-axis current and the response time constant of the q-axis current of the R drive motor 4r, respectively. Also, "L _d " and "L _q " represent the d-axis inductance and q-axis inductance of the R drive motor 4r, respectively. Note that the d-axis inductance L _d and the q-axis inductance L _q may use values at a predetermined representative operating point, or may use values determined by referring to predetermined map data.

The field flux estimation unit 902 receives the R first f-axis current command value i _fr1 ^* as an input and calculates the field flux estimation value φ^ _f according to the following equation (38).
In the formula, " _Mf " represents the mutual inductance between the stator and rotor of the R drive motor 4r. The mutual inductance _Mf may be a value at a predetermined representative operating point, or may be a value determined by referring to predetermined map data. Furthermore, " _τf " is the response time constant of the f-axis current in the R drive motor 4r.

Then, the magnetic flux estimated value φ _^ is calculated as the sum of the reluctance torque equivalent magnetic flux estimated value φ^ _r and the field magnetic flux estimated value φ^f, and is input to the torque calculation unit 903.

The torque calculation unit 903 receives the R first q-axis current command value i _qr1 ^* and the magnetic flux estimation value φ^ as input, and calculates the R estimated torque T^ _mr using the following equation (39).
In the formula, "p _n " represents the number of pole pairs.

II-3. R vibration suppression control calculation processing Fig. 10 is a block diagram showing the configuration of vibration suppression control calculation unit 803. As shown in the figure, vibration suppression control calculation unit 803 has an F/F compensation calculation unit 1001, a first delay correction unit 1002, a pre-correction motor angular velocity estimator 1003, a corrected motor angular velocity estimator 1004, a second delay correction unit 1005, and an F/B compensation calculation unit 1006.

The F/F compensation calculation unit 1001 receives the R estimated torque ^ _mr as input, executes the F/F compensation process expressed by the above equation (24), and calculates the R first torque command value T _mr1 .

In order to take into account the influence of the communication delay T1 [s] on the F estimated torque T^ _mf caused by communication between the vehicle controller 30, the F motor controller 31f, and the R motor controller 31r, the first delay correction unit 1002 performs processing defined by the following equation (40) on the R estimated torque T^ _mr to calculate the R estimated torque delay correction value T^' _mf .

The pre-correction motor angular velocity estimator 1003 receives the R estimated torque delay correction value T̂′ _mf as input, and calculates the pre-correction R motor angular velocity estimate value using the transfer characteristic G _rr (s) expressed by the above equation (23).

The corrected motor angular velocity estimator 1004 receives the F estimated torque Tr _mr as input and calculates a corrected R motor angular velocity estimate using the transfer characteristic G _rfr (s) expressed by the above equation (33).

Then, the R motor angular velocity estimated value ω^ _mr is calculated by summing the uncorrected R motor angular velocity estimated value and the corrected R motor angular velocity estimated value.

In order to take into account the influence of the communication delay T1 [s] on the F estimated torque T^ _mf due to the above communication, the second delay correction unit 1005 performs processing defined by the following equation (41) on the R motor angular velocity detection value ω _mr to calculate the R motor angular velocity delay correction value ω' _mr .
However, "T2" in the formula represents the delay time [s] due to the control calculation.

The F/B compensation calculation unit 1006 subtracts the R motor angular velocity delay correction value ω' _mr from the R motor angular velocity estimated value ω^ _mr , and applies a band-pass filter H _r (s) to this value and the inverse system of the transfer characteristic G _pr (s) shown in the above equation (22), thereby calculating the R second torque command value T _mr2 .

The band-pass filter _Hr (s) is set so that the attenuation characteristics of the low-pass side and the high-pass side are approximately the same and the torsional resonance frequency of the drivetrain is near the center of the pass band on a logarithmic axis (log scale). For example, when the band-pass filter _Hr (s) is composed of a first-order high-pass filter and a first-order low-pass filter, the band-pass filter _Hr (s) is configured as shown in the following equation (42).
where τ _Hr = 1/(2πf _HCr ), f _HCr = kr·f _pr , τ _Lr = 1/(2πf _LCr ), f _LCr = f _pr /k _r , where frequency f _pr is the torsional resonance frequency of the R drive system S _r , and k _r is an arbitrary value that constitutes a bandpass.

Then, the vibration suppression control calculation unit 803 calculates the R-th third torque command value T _{mr3 by taking the sum of the R-th first torque command value T mr1 and} the R-th second torque command value T _mr2 , and outputs the result to the second current command value calculation unit 804 shown in FIG. 8.

II-4. R Second Current Command Value Calculation Process The second current command value calculation unit 804 receives the R third torque command value T _mr3 and the magnetic flux estimation value φ^ as input and calculates the R second q-axis current command value i _qr2 ^* using the following equation (43).

Second Embodiment
The second embodiment will be described below, with the same elements as those in the first embodiment being given the same reference numerals and their description being omitted.

In this embodiment, we will explain the control executed in an electric vehicle 200 that has one F drive motor 4f at the front and independent RR drive motors 4rr and RL drive motors 4rl on the left and right rear wheels. In particular, in this embodiment, the F drive motor 4f is configured as a wound field synchronous motor, and the RR drive motor 4rr and RL drive motor 4rl are both configured as induction motors (IMs).

11 is a block diagram showing the main configuration of an electric vehicle 200 according to this embodiment. As shown in the figure, the electric vehicle 200 differs from the electric vehicle 100 of the first embodiment in that it is equipped at the rear with a RR drive system Srr that provides drive force to the _RR drive wheels 9rR and a RL drive system _Srl that provides drive force to the RL drive wheels 9rL.

The basic flow of processing by the vehicle controller 30 shown in Figure 2 and the basic flow of processing by each motor controller 31 shown in Figure 4 can be applied in the same way as in the first embodiment, except for the increase in the number of various control parameters resulting from the installation of two rear R drive motors 4rr, 4rl. Therefore, the following description will focus on processing that differs from the first embodiment.

First, in this embodiment, the F drive motor 4f is configured as a wound-field synchronous motor, and the R drive motors 4rr and 4rl are configured as induction motors, so the current command value calculation process (step S404 in Figure 4) and the current control calculation process (step S405) differ from the first embodiment.

Specifically, in the current command value calculation process of step S404, the R motor controller 31r (31rr, 31rl) calculates γδ-axis current command values ( _iγrr ^* , _iδrr ^* ), (iγrl*, _iδrl * ⁾ as the current command value i ^* based on the third torque command values _Tmrr3 , _Tmrl3 calculated in the vibration _suppression ^control calculation process described later.

Then, in the current control calculation process of step S405, the F motor controller 31f determines the F-PWM signals (t uf , t vf , t _wf ) for driving the F inverter 3r based on the F three-phase voltage command values (v _uf , _{v vf ,} v _wf ), the Ff axis voltage command value v _ff ^* , and the DC voltage value V _dc , in the same way as the processing of the R motor controller 31r in _the first embodiment.

Meanwhile, the R motor controllers 31rr and 31rl convert the R three-phase current values (i _urr , i _vrr , i _wrr ), (i _url , i _vrl , i _wrl ) from a three-phase AC coordinate system (uvw axes) to an orthogonal two-axis DC coordinate system (γδ axes). The orthogonal two-axis DC coordinate system is a coordinate system that rotates at a power supply angular velocity ω, which will be described later. In particular, the R motor controllers 31rr and 31rl calculate the γ-axis current (excitation current) _iγ and the δ-axis current (torque current) _iδ based on the R three-phase current values and the power supply angle θ obtained by integrating the power supply angular velocity ω.

Furthermore, each R motor controller 31r receives the γ-axis current _iγ and the δ-axis current _iδ as inputs and calculates the slip angular velocity _ωse using the following equations (44) and (45).
In the formula, "M", " _Rr ", and " _Lr " are parameters of the induction motor, representing mutual inductance, rotor resistance, and rotor self-inductance, respectively. Also, " _τφ " represents the response time constant of the rotor magnetic flux. The power supply angular velocity _ω is the sum of the electrical angular velocity _ωer and the slip angular velocity ωse.

By performing the above-described slip frequency control, it is possible to determine the induction motor torque proportional to the product of the γ-axis current (excitation current) i _γ and the δ-axis current (torque current) i _δ .

Next, each R motor controller 31r calculates the specified γδ-axis voltage values (v _γrr ^* , v _δrr ^* ), (v _γrl ^* , v _δrl ^* ) based on the deviation between the specified γδ-axis current values (i _γrr ^* , i _δrr ^* ), (i _γrl ^* , i _δrl ^* ) calculated in step S404 and the γδ-axis current (i _γ , i _δ ). Note that decoupling control may be performed in this calculation as appropriate.

Then, each R motor controller 31r calculates R three-phase voltage command values (v _urr ^, v _vrr , v ^wrr ), (v _url , v _vrl , v ^wrl ) based on the γδ-axis voltage command values (v _γrr ^* , v _{δrr *} ), (v _{γrl *} , v _{δrl *} ) and the power supply angle θ. Furthermore, the R motor controller 31r determines R-PWM signals (t _urr , t _vrr , t _wrr ) and (t _url , t _vrl , t _wrl ) [%] for driving the R inverters 3rr and 3rl based on the R three _- phase voltage command values (v _urr , v _vrr , v _wrr ), (v _url , v _vrl , v _wrl ) and the DC voltage value V dc. The R-PWM signals thus determined open and close the switching elements of the RR inverters 3rr and 3rl, thereby driving the RR drive motor 4rrRL and drive motor 4rl with the desired torque.

Next, we will explain in detail the estimated torque calculation process, vibration suppression control calculation process, and current command value calculation process in the F motor controller 31f and R motor controller 31r.

<I.F motor controller>
12 is a block diagram showing the control configuration of the F motor controller 31f. As shown in the figure, the F motor controller 31f has a first current command value calculation unit 1201 that executes an F first current command value calculation process, an estimated torque calculation unit 1202 that executes an F estimated torque calculation process, a vibration suppression control calculation unit 1203 that executes an F vibration suppression control calculation process, and a second current command value calculation unit 1204 that executes an F second current command value calculation process.

I-1. F first current command value calculation process The first current command value calculation unit 1201 receives the F target torque command value T _mf ^* , the F motor angular velocity detection value ω _mf , and the DC voltage value V _dc as input, and calculates the F first dq-axis current command values (i _df1 ^* , i _qf1 ^* ) and the F first f-axis current command value i _ff1 ^* by referring to a table stored in advance in a predetermined storage area.

I-2. F Estimated Torque Calculation Process The estimated torque calculation unit 1202 calculates the F estimated torque T^ _mf and the magnetic flux estimated value φ^ by the same process as that in the estimated torque calculation unit 802 shown in FIG.

I-3. F Vibration Suppression Control Calculation Processing The vibration suppression control calculation unit 1203 uses a model of the driving force transmission system for one wheel of the electric vehicle 200 to perform correction to suppress vibration in the driving force transmission system.

Figure 13 shows a model of the driving force transmission system of the electric vehicle 200. The definitions of each parameter, including those already explained, are shown below.

J _m : Motor inertia J _wf : Drive wheel inertia (for one axle)
_Kd : Torsional rigidity of drive shaft _Kt : Coefficient of friction between tire and road surface N: Overall gear ratio r: Tire load radius _ωm : Motor angular velocity _θm : Motor angle _ωw : Drive wheel angular velocity _θw : Drive wheel angle _Tm : Motor torque _Td : Drive shaft torque F: Driving force (for one shaft)
θ _d : Torsion angle of drive shaft ω _d : Torsion angular velocity of drive shaft V: Vehicle speed M: Vehicle weight

According to FIG. 13, the equations of motion of the electric vehicle 200 are expressed by the following equations (46) to (51).

By Laplace transforming the above equations (46) to (51), the transfer characteristics from the motor torque T _m to the motor angular velocity ω _m are expressed by the following equation (52).
However, each coefficient in equation (52) is expressed by the following equation (53).

Further, the transfer characteristic from the motor torque _Tm to the drive shaft torque _Td is expressed by the following equation (54).

On the other hand, when the transfer characteristic from the motor angular velocity ω _m to the drive wheel velocity ω _w is calculated from the equations (47), (49), (50), and (51), the following equation (55) is obtained.

Then, when the transfer characteristic from the motor torque T _m to the drive wheel speed ω _w is calculated using equations (52) and (55), the following equation (56) is obtained.

Furthermore, when the transfer characteristics from the drive shaft torque _Td to the drive wheel speed _ωw are calculated using equations (54) and (56), the following equation (57) is obtained.

Here, the following equation (58) is obtained from the above equations (53) to (57).

From equations (57) and (58), the drive shaft torsional angular velocity _ωd is expressed by the following equation (59).

However, the coefficients "v ₁ ", "v ₀ ", "w ₁ ", and "w ₀ " in equation (59) and the function H _w (s) are determined by the following equation (60).

Moreover, by modifying the above equation (54), the following equation (61) is obtained.
In the equation (61), "ζ _p " represents the damping coefficient of the drive shaft torque transmission system, and "ω _p " represents the natural vibration frequency of the drive shaft torque transmission system.

Furthermore, since the pole α and the zero c ₀ /c ₁ in equation (61) can be considered to be approximately equal, the following equation (62) can be obtained by performing pole-zero cancellation.

Here, the torque command value T _mff after vibration suppression control (particularly after F/F compensation) is expressed as in the following equation (63).

Then, equation (63) can be rewritten as the following equation (64).

When T _m =T _mff and equation (64) is substituted into equation (62), the following equation (65) is obtained.

Furthermore, the reference response from the motor torque _Tm to the drive shaft torque _Td is expressed by the following equation (66).

As a condition for the above equations (65) and (66) to coincide, the following equation (67) is obtained.

Next, if the backlash characteristics from the motor 4 to the drive shaft Ds are modeled using a dead zone, the drive shaft torque _Td is expressed by the following equation (68).
However, "θ _dead " in equation (61) represents the overall backlash amount from the drive motor 4 to the drive shaft Ds.

Figure 14 is a block diagram showing the configuration of the vibration suppression control calculation unit 1203. As shown in the figure, the vibration suppression control calculation unit 1203 has an F/F compensation calculation unit 1401, a first delay correction unit 1402, a vehicle model 1403, a second delay correction unit 1404, and an F/B compensation calculation unit 1405.

15 is a block diagram showing the configuration of the F/F compensation calculation unit 1401. As shown in the figure, the F/F compensation calculation unit 1401 receives the F estimated torque ^ _mf as an input and calculates a torsional angular velocity estimated value ω^ _df based on the vehicle transfer characteristics configured using a dead zone model that simulates gear backlash. Furthermore, the F first torque command value Tmf1 is calculated by subtracting a value (F/F compensation torque) obtained by multiplying the torsional angular velocity estimated value ω^ _df by the gain k defined by equation (67) from the F estimated _torque ^ _mf .

In order to take into account the influence of the communication delay T1 [s] of the RR estimated torque T^ _mrr and the RL estimated torque T^ _mrl caused by communication between the vehicle controller 30 and each motor controller 31, the first delay correction unit 1402 performs processing defined by the following equation (69) on the F estimated torque T^ _mf to calculate the F estimated torque delay correction value T^' _mf .

The vehicle model 1403 receives the F estimated torque delay correction value T^' _mf , the RR estimated torque T^ _mrr , and the RL estimated torque T^ _mrl , and calculates the F motor angular velocity estimated value ω^ _mf .

15 shows the configuration of vehicle model 1403. As shown in the figure, vehicle model 1403 is configured with a dead-band model that simulates vehicle parameters and gear backlash for each of the drivetrains _Sf , _Srr , and _Srl . Therefore, the reference motor angular velocity estimated values ω^ _mf , ω^ _mrr , and ω^ _mrl can be calculated by multiplying the torsional angular velocity estimated values ω^ _df , ω^ _drr , and ω^ _drl of each drivetrain by each gain _kf , _krr , and _krl determined respectively by equation (67) and subtracting the obtained value from each corrected estimated torque.

Returning to FIG. 14 , in order to take into account the influence of the communication delay T1 [s] of the RR estimated torque T^ _mrr and the RL estimated torque T^ _mrl , the second delay correction unit 1404 performs processing defined by the following equation (70) on the F motor angular velocity detection value ω _mf to calculate the F motor angular velocity delay correction value ω′ _mf .
However, "T2" in the formula represents the delay time [s] due to the control calculation.

The F/B compensation calculation unit 1405 subtracts the F motor angular velocity delay correction value ω' _mf from the F motor angular velocity estimated value ω^ _mf , and applies the inverse system of the band-pass filter H _f (s) shown in equation (36) and the transfer characteristic G _p (s) shown in equation (19) to the subtracted value, thereby calculating the F second torque command value T _mf2 .

Then, the vibration suppression control calculation unit 1203 calculates the F third torque command value T _mf3 by taking the sum of the F first torque command value T _mf1 and the F second torque command value T _mf2 , and outputs it to the second current command value calculation unit 1204 shown in FIG. 12.

I-4. F second current command value calculation processing The second current command value calculation unit 1204 shown in FIG. 12 receives the F third torque command value T _mf3 , the F motor angular velocity detection value ω _mf , and the magnetic flux estimation value φ^ as input, and calculates the F second q-axis current command value i _qf2 ^* using the following equation (71):

<II. RR motor controller>
17 is a block diagram showing the control configuration of the RR motor controller 31rr. As shown in the figure, the RR motor controller 31rr has a first current command value calculation unit 1701 that executes RR first current command value calculation processing, an estimated torque calculation unit 1702 that executes RR estimated torque calculation processing, a vibration suppression control calculation unit 1703 that executes RR vibration suppression control calculation processing, and a second current command value calculation unit 1704 that executes RR second current command value calculation processing.

II-1. RR First Current Command Value Calculation Process The first current command value calculation unit 1701 receives the RR target torque command value T _mrr ^* , the RR motor angular velocity detection value ω _mrr , and the DC voltage value V _dc as input, and calculates the RR first γδ-axis current command values (i _γrr1 ^* , i _δrr1 ^* ) by referring to a table stored in advance in a predetermined storage area.

18 is a block diagram showing the configuration of the estimated torque calculation unit 1702. As shown in the figure, it has a magnetic flux estimation unit 1801 and a torque calculation unit 1802.

The magnetic flux estimation unit 1801 receives the RR first γ-axis current command value i _γrr1 ^* as an input and calculates the magnetic flux estimation value φ^ _γ according to the following equation (72).
In the equation, "τ _φ ,""τ _δ ," and "τ _γ " represent the response time constant of the rotor magnetic flux, the response time constant of the δ-axis current, and the response time constant of the γ-axis current in the RR drive motor 4rr, respectively. Also, "M" represents the mutual inductance between the stator and rotor in the RR drive motor 4rr. Note that the mutual inductance M may be a value at a predetermined representative operating point, or may be a value determined by referring to predetermined map data.

A torque calculation unit 1802 receives the RR first δ-axis current command value i _δrr1 ^* and the magnetic flux estimation value φ^ _γ as input, and calculates the RR estimated torque T^ _mrr using the following equation (73).
In the equation, "K _T " represents a coefficient determined by each parameter of the induction motor.

19 is a block diagram showing the configuration of vibration suppression control calculation unit 1703. As shown in the figure, vibration suppression control calculation unit 803 has an F/F compensation calculation unit 1901, a first delay correction unit 1902, a vehicle model 1903, a second delay correction unit 1904, and an F/B compensation calculation unit 1905.

Vibration suppression control calculation unit 1703 calculates an RR third torque command value T _mrr2 using the same calculation logic as vibration suppression control calculation unit 1203 described in FIG. 14, and outputs it to second current command value calculation unit 1704 shown in FIG.

II-4. RR Second Current Command Value Calculation Process The second current command value calculator 1704 receives the RR third torque command value T _mrr2 and the magnetic flux estimation value φ^ _γ as input and calculates the RR second δ-axis current command value i _δrr2 ^* using the following equation (74):

<III. RL Motor Controller>
20 is a block diagram showing the control configuration of the RL motor controller 31rl. As shown in the figure, the RL motor controller 31rl has a first current command value calculation unit 2001 that executes an RL first current command value calculation process, an estimated torque calculation unit 2002 that executes an RL estimated torque calculation process, a vibration suppression control calculation unit 2003 that executes an RL vibration suppression control calculation process, and a second current command value calculation unit 2004 that executes an RL second current command value calculation process.

The components of the RL motor controller 31rl execute the same processes as those of the RR motor controller 31rr shown in FIG. 17 to calculate the RL estimated torque T^ _mrl , the RL first specified γ-axis current value i _γrl1 ^* , and the RL second specified δ-axis current value i _δrl2 ^* .

[Third embodiment]
The third embodiment will be described below. Elements similar to those in the first to third embodiments are designated by the same reference numerals, and their description will be omitted.

In this embodiment, we will explain the control performed in an electric vehicle 300 that has independent FR drive motors 4fr and FL drive motors 4fl on the front left and right, and independent RL drive motors 4rl and RR drive motors 4rr on the rear left and right.

In particular, in this embodiment, both the FR drive motor 4fr and the FL drive motor 4fl are configured as interior permanent magnet synchronous motors, and both the RL drive motor 4rl and the RR drive motor 4rr are configured as induction motors.

21 is a block diagram showing the main configuration of an electric vehicle 200 according to this embodiment. As shown in the figure, the electric vehicle 300 differs from the electric vehicle 100 of the first embodiment in that it is equipped at the front with an FR drive system _Sfr that provides driving force to the FR drive wheels 9fR and an FL drive system _Sfl that provides driving force to the FL drive wheels 9fL, and at the rear with an RR drive system _Srr that provides driving force to the RR drive wheels 9rR and an RL drive system _Srl that provides driving force to the RL drive wheels 9rL.

The processes shown in Figures 2 and 4 for the front can be similarly applied to those described in the first embodiment, except for the increase in the number of control parameters resulting from the provision of two F drive motors 4fr, 4fl. The processes shown in Figures 2 and 4 for the rear are the same as those in the second embodiment. Therefore, for the sake of simplicity, the following description will focus on the details of the estimated torque calculation process, vibration damping control calculation process, and current command value calculation process.

<I. FR, FL motor controller>
Fig. 22 is a block diagram showing the configuration of the FR motor controller 31fr, and Fig. 23 is a block diagram showing the configuration of the FL motor controller 31fl.

As shown in the figure, the FR motor controller 31fr has an estimated torque calculation unit 2201, a vibration suppression control calculation unit 2202, and a current command value calculation unit 2203. The FL motor controller 31fl also has an FL estimated torque calculation unit 2301, a vibration suppression control calculation unit 2302, and a current command value calculation unit 2303. For ease of explanation, the following will collectively describe the FR and FL components by their respective reference numerals, where appropriate. For example, the estimated torque calculation unit 2201 and the FL estimated torque calculation unit 2301 will be collectively referred to as "estimated torque calculation units 2201, 2301."

I-1. FR and FL Estimated Torque Calculation Process The estimated torque calculation units 2201 and 2301 calculate the FR estimated torque ^ _mfr and the FL estimated torque ^ _mfl by the same process as that performed by the estimated torque calculation unit 501 described with reference to FIG.

I-2. FR, FL Vibration Suppression Control Calculation Processing Fig. 24 is a block diagram showing the configuration of vibration suppression control calculation unit 2202. Fig. 25 is a block diagram showing the configuration of vibration suppression control calculation unit 2302. As shown in the figure, vibration suppression control calculation unit 2202 has an F/F compensation calculation unit 2401, a first delay correction unit 2402, a vehicle model 2403, a second delay correction unit 2404, and an F/B compensation calculation unit 2405. In addition, vibration suppression control calculation unit 2302 has an F/F compensation calculation unit 2501, a first delay correction unit 2502, a vehicle model 2503, a second delay correction unit 2504, and an F/B compensation calculation unit 2505.

The F/F compensation calculation units 2401 and 2501 calculate the FR first torque command value T _mfr1 and the FL first torque command value T _mfl1 by the same processing as that by the F/F compensation calculation unit 1401 described with reference to FIG.

The first delay correction units 2402, 2502 perform correction taking into account communication delays on the FR estimated torque T^ _mfr and the FL estimated torque T^ _mfl , respectively, in the same manner as the first delay correction unit 1402 described in Figure 14, and calculate the FR estimated torque delay correction value T^' _mfr and the FL estimated torque delay correction value T^' _mfl .

Vehicle model 2403 of vibration suppression control calculation unit 2202 receives FR estimated torque delay correction value T^' _mfr , FL estimated torque T^ _mfl , RR estimated torque T^ _mrr , and RL estimated torque T^ _mrl , and calculates FR motor angular velocity estimated value ω^ _mfr .

Vehicle model 2503 of vibration suppression control calculation unit 2302 receives FL estimated torque delay correction value T^' _mfl , FR estimated torque T^ _mfr , RR estimated torque T^ _mrr , and RL estimated torque T^ _mrl as inputs and calculates FL motor angular velocity estimated value ω^ _mfl .

26 shows the configuration of vehicle models 2403, 2503. As shown in the figure, vehicle models 2403, 2503 are configured with dead-band models that simulate vehicle parameters and gear backlash for each of drivetrains _Sfr , _Sfl , _Srr , and _Srl . Therefore, the reference motor angular velocity estimated values ω^ _mfr , ω^ _mfl , ω^ _mrr , and ω^ _mrl can be calculated by multiplying the torsional angular velocity estimated values ω^ _dfr , ω^ _dfl , ω^ _drr , and ω^ _drl of each drivetrain by the respective gains kfr, kfl, _krr , and _krl determined by _equation ( ₆₇ ) and subtracting the obtained value from each corrected estimated torque.

The second delay correctors 2404 and 2504 calculate the FR motor angular velocity delay correction value ω' _mfr and the FL motor angular velocity delay correction value ω' _mfl by the same processing as that performed by the second delay corrector 1404 described in FIG.

The F/B compensation calculation units 2405 calculate the FR second torque command value T _mfr2 and the FL second torque command value T _mfl2 by the same processing as that performed by the F/B compensation calculation unit 706 described with reference to FIG.

Then, the vibration suppression control calculation units 2202, 2302 calculate F third torque command values _Tmfr3 , _Tmfl3 by taking the sum of the F first torque command values _Tmfr1 , _Tmfl1 and the F second torque command values _Tmfr2 , _Tmfl2 , and output them to the current command value calculation units 2203, 2303.

I-3. FR, FL Current Command Value Calculation Processing The current command value calculation units 2203, 2303 calculate the FR-dq-axis current command values (i _dfr ^* , i _qfr ^* ) and the FL-dq-axis current command values (i _dfl ^* , i _qfl ^* ) by processing similar to that performed by the current command value calculation unit 503 described in FIG. 4.

<II. RR, RL motor controller>
Fig. 27 is a block diagram showing the configuration of the RR motor controller 31rr, and Fig. 28 is a block diagram showing the configuration of the RL motor controller 31rl.

As shown in the figure, the RR motor controller 31rr has a first current command value calculation unit 2701, an estimated torque calculation unit 2702, a vibration suppression control calculation unit 2703, and a second current command value calculation unit 2704. The RL motor controller 31rl also has a first current command value calculation unit 2801, an estimated torque calculation unit 2802, a vibration suppression control calculation unit 2803, and a second current command value calculation unit 2804. For simplicity's sake, the following explanation will be given collectively, with the reference symbols for the FR and FL components used where appropriate. For example, the first current command value calculation unit 2701 and the first current command value calculation unit 2801 will be collectively referred to as "first current command value calculation units 2701, 2801."

II-1. RR, RL First Current Command Value Calculation Process The first current command value calculators 2701, 2801 calculate the RR first γδ-axis current command values ( _iγrr1 *, _iδrr1 ^{*) and the RL first γδ-axis current command values (iγrl1*, iδrl1*} ₎ ^by _processing ^similar to the processing by the first current command value calculator 1701 described in FIG. 17 and the first current command value calculator 2001 described in ^FIG . 20, respectively.

II-2. RR and RL Estimated Torque Calculation Processing The estimated torque calculation units 2702 and 2802 calculate the RR estimated torque ^ _mrr and the RL estimated torque ^ _mrl , respectively, by processing similar to the processing by the estimated torque calculation unit 1702 and the estimated torque calculation unit 1702 described in FIG. 18 .

II-3. RR, RL Vibration Suppression Control Calculation Processing Fig. 29 is a block diagram showing the configuration of vibration suppression control calculation unit 2703. As shown in the figure, vibration suppression control calculation unit 2703 has an F/F compensation calculation unit 2901, a first delay correction unit 2902, a vehicle model 2903, a second delay correction unit 2904, and an F/B compensation calculation unit 2905. Fig. 30 is a block diagram showing the configuration of vibration suppression control calculation unit 2803. As shown in the figure, vibration suppression control calculation unit 2803 has an F/F compensation calculation unit 3001, a first delay correction unit 3002, a vehicle model 3003, an RL second delay correction unit 3004, and an F/B compensation calculation unit 3005.

Vibration suppression control calculation units 2703 and 2803 calculate R third torque command values T mrr3 and T _mrl3 by processing similar to the processing by vibration suppression control calculation units 2202 and 2302 described in Figures 24 and ₂₅ , respectively, and output them to second current command value calculation units 2704 and 2804.

II-4. RR, RL Second Current Command Value Calculation Process The second current command value calculators 2704, 2804 calculate the RR second δ-axis current command value i _δrr2 ^{* and the RL second δ-axis current command value i δrl2 *} by processing similar to the processing performed by the second current command value calculator 1704 described in FIG. 17 and the second current command value calculator ²⁰⁰⁴ described in FIG. ₂₀ .

[Control results]
Below, the control results according to each embodiment will be explained while comparing them with the control results according to the reference example.

Example 1
As Example 1, the electric vehicle control method of the first embodiment is assumed, that is, a method for controlling an electric vehicle 100 in which the F drive motor 4f is an interior permanent magnet synchronous motor and the R drive motor 4r is a wound-field synchronous motor. On the other hand, the control of Comparative Example 1 is assumed to be the same as Example 1, except that communication delays between the controllers 31 are not taken into consideration, i.e., correction processes by the delay correction units 702, 705, 1002, and 1005 are not executed.

Fig. 31 is a timing chart illustrating the control results of Example 1 and Comparative Example 1. In particular, Fig. 31 shows the behavior of the F output torque, the R output torque, and the longitudinal acceleration when the F target torque command value _Tmf ^* and the R target torque command value _Tmr ^* are changed in steps at time t1.

As shown in the figure, in Comparative Example 1, a negative torque correction is applied that prevents vehicle acceleration from times t1 to t3. As a result, neither the F output torque nor the R output torque reaches the intended value, and it can be seen that longitudinal acceleration is particularly limited around time t2 compared to time t3. In other words, with the control in Comparative Example 1, vehicle acceleration is prevented, and acceleration/deceleration behavior according to the amount of accelerator pedal/brake pedal operation (driver's intention) is not achieved, which may cause discomfort to the driver.

In contrast, in Example 1, both the F output torque and the R output torque behave in line with the driver's intentions over the period from time t1 to t3. This is thought to be because corrections were made in the vibration suppression control that took into account communication delays between the controllers 31, thereby suppressing unnecessary vibration suppression compensation (corrections on the negative torque side) due to each F/B compensation calculation.

Note that, although the first embodiment has been described with a focus on when the electric vehicle 100 is accelerating (when the drive motors 4f, 4r are in power running mode), the same effect can be achieved when the electric vehicle 100 is decelerating (when the drive motors 4f, 4r are in regenerative running mode). In other words, even during regenerative running mode, unnecessary vibration suppression compensation (correction on the positive torque side) by each feedback compensation calculation is similarly suppressed, so the deceleration behavior intended by the driver can be achieved.

Example 2
The control of Example 2 is assumed to be the electric vehicle control method of the second embodiment, i.e., a method for controlling an electric vehicle in an electric vehicle 200 in which the F drive motor 4f is a wound-field synchronous motor and the RL drive motor 4rl and the RR drive motor 4rr are induction motors. On the other hand, the control of Comparative Example 2 is assumed to be the same as that of Example 2, except that communication delays between the controllers are not taken into consideration, i.e., correction processes by the delay correction units 1402, 1404, 1902, and 1904 are not executed.

Fig. 32 is a timing chart illustrating the control results of Example 2 and Comparative Example 2. In particular, Fig. 32 shows the behavior of the F output torque, RR output torque, RL output torque, and longitudinal acceleration when the F target torque command value _Tmf ^* , RR target torque command value _Tmrr ^* , and RL target torque command value _Tmrl ^* are changed in steps at time t1.

As shown in the figure, in Comparative Example 2 as well, negative torque correction is applied, preventing vehicle acceleration from times t1 to t3. As a result, none of the F output torque, RR output torque, and RL output torque reach their intended values, and it can be seen that longitudinal acceleration is particularly limited around time t2 compared to time t3. In other words, in Comparative Example 2 as well, vehicle acceleration is prevented, and acceleration/deceleration behavior according to the driver's intention is not achieved, which may cause the driver to feel uncomfortable.

In contrast, in Example 2, the F output torque, RR output torque, and RL output torque all behave in line with the driver's intentions over the period from time t1 to t3. This is thought to be because corrections were made in the vibration suppression control that took into account communication delays between controllers, thereby suppressing unnecessary vibration suppression compensation (corrections on the negative torque side) due to each F/B compensation calculation.

Note that, although the second embodiment has been described with a focus on acceleration of the electric vehicle 200 (when the drive motors 4f, 4rr, and 4rl are in power running mode), the same effect can be achieved during deceleration (when the drive motors 4f, 4rr, and 4rl are in regenerative running mode). In other words, during regenerative running mode, unnecessary vibration suppression compensation (correction on the positive torque side) by each feedback compensation calculation is similarly suppressed, so that the deceleration behavior intended by the driver can be achieved.

Example 3
The control of Example 3 is assumed to be the electric vehicle control method of the third embodiment, that is, a method for controlling an electric vehicle in an electric vehicle 300 in which the FR drive motor 4fr and the FL drive motor 4fl are interior permanent magnet synchronous motors and the RL drive motor 4rl and the RR drive motor 4rr are induction motors. On the other hand, the control of Comparative Example 3 is assumed to be the same as that of Example 3, except that communication delays between the controllers are not taken into consideration, i.e., delay correction processing by the delay correction units 2402, 2404, 2502, and 2504 is not performed.

Fig. 33 is a timing chart illustrating the control results of Example 3 and Comparative Example 3. In particular, Fig. 33 shows ^{the behavior of the FR output torque, FL output torque, RR output torque, RL output torque, and longitudinal acceleration when the FR target torque command value Tmfr*, FL target torque command value Tmfl*} _{, RR} ^target _torque ^command value Tmrr*, and RL target torque command value _Tmrl ^* are changed in steps at time t1.

As shown in the figure, in Comparative Example 3 as well, negative torque correction is applied, preventing vehicle acceleration from times t1 to t3. As a result, none of the FR output torque, FL output torque, RR output torque, and RL output torque reach their intended values, and it can be seen that longitudinal acceleration is particularly limited around time t2 compared to time t3. In other words, in Comparative Example 2 as well, vehicle acceleration is prevented, and acceleration/deceleration behavior according to the driver's intention is not achieved, which may cause the driver to feel uncomfortable.

In contrast, in Example 3, the FR output torque, FL output torque, RR output torque, and RL output torque all behave in line with the driver's intentions over the period from time t1 to t3. This is thought to be because corrections were made in the vibration suppression control that took into account communication delays between controllers, thereby suppressing unnecessary vibration suppression compensation (corrections on the negative torque side) due to each F/B compensation calculation.

Note that, although the second embodiment has been described with a focus on acceleration of the electric vehicle 300 (when the drive motors 4fr, 4fl, 4rr, and 4rl are in power running mode), the same effect can be obtained during deceleration (when the drive motors 4fr, 4fl, 4rr, and 4rl are in regenerative mode). In other words, during regenerative mode, unnecessary vibration suppression compensation (correction on the positive torque side) by each feedback compensation calculation unit is similarly suppressed, so that the deceleration behavior intended by the driver can be achieved.

[Action and effect]
The configurations and the resulting effects of the above-described embodiments will now be described together.

In the following description, "one motor controller" refers to either the F motor controller 31f or the R motor controller 31r in the first embodiment, any one of the F motor controller 31f, the RR motor controller 31rr, and the RL motor controller 31rl in the second embodiment, and any one of the FR motor controller 31fr, the FL motor controller 31fl, the RR motor controller 31rr, and the RL motor controller 31rl in the third embodiment. Also, "another motor controller" refers to one or more of the motor controllers 31 other than "one motor controller."

According to each embodiment, an electric vehicle control method is provided in which an electric vehicle 100 equipped with multiple drive motors 4 (for example, the F drive motor 4f and R drive motor 4r in the first embodiment) controls each drive motor 4f, 4r based on current command values i ^* (F-dq-axis current command values (i _df ^* , i _qf ^* ) and R-second q-axis current command value i _qr2 ^* ) respectively determined for each drive motor 4f, 4r.

In this electric vehicle control method, each motor controller 31 (F motor controller 31f and R motor controller 31r) that controls each drive motor 4f, 4r executes an estimated torque calculation process (step S402 in Figure 4) that calculates each estimated torque T ^{^} (F estimated torque T ^{^mf} _and R estimated torque T^ _mr ) based on each target torque command value _Tm * (F target torque command value Tmf _* and R target torque command value _Tmr ^* ) that corresponds to the response characteristics and required output of each drive motor 4f, 4r.

In addition, one motor controller (here, the F motor controller 31f) is caused to execute an estimated torque output process in which the calculated first estimated torque (F estimated torque T^ _mf ) is output to another motor controller (the R motor controller 31r); a torque command value correction process (step S403) in which the F target torque command value _Tmf ^* or the F estimated torque T^ _mf is corrected based on the rotational state (F motor angular velocity _ωmf ) of the first drive motor (F drive motor 4f) to be controlled to obtain a corrected torque command value (F third torque command value _Tmf3 ); and a current command value calculation process (step S404) in which a current command value (F-dq axis current command value (i _df ^* , i _qf ^* )) of the F drive motor _4f (or the R drive motor 4r) is calculated from the F third torque command value Tmf3.

In particular, in the torque command value correction process, the F motor angular velocity detection value ω _mf is corrected based on the second estimated torque (R estimated torque ^ _mr ) calculated by the R motor controller 31r, taking into account the communication delay between the motor controllers (second delay correction unit 705).

As a result, in an electric vehicle 100 equipped with multiple drive motors 4, the rotation state taking into consideration communication delays between the motor controllers can be referenced in the control calculation that corrects the target torque command value T _m ^* based on the rotation state of the drive motor 4 that is the control target of one motor controller 31. This makes it possible to reduce delays in torque response caused by the communication delays, and to achieve torque response that corresponds to the intended behavior of the electric vehicle.

Furthermore, by adopting a configuration in which the F motor controller 31f and the R motor controller 31r calculate the F estimated torque ^ _mf and the R estimated torque ^ _mr , respectively, concentration of the calculation load on a specific controller is prevented.

Furthermore, according to each embodiment, the torque command value correction process includes an FF compensation process ( _F /F compensation calculation unit 701 in FIG. 7) that calculates an FF compensated torque command value (F first torque command value T _mf1 ⁾ by performing a feedforward calculation to suppress vibrations in the driving force transmission system of the electric vehicle 100 for the F target torque command value T _{mf *} or F estimated torque T^ _mf of the first drive motor (here, F drive motor 4f), and an FB compensation process (702 to 706 in FIG. 7) that calculates an FB compensated torque command value (F third torque command value T mf3 ), which is the corrected torque command value, by performing a feedback calculation to suppress vibrations in the driving force transmission system using a detected value of the rotational state of the F drive motor _4f (F motor angular velocity detected value ω mf ) for the F first torque command value T _mf1 .

In particular, in the FB compensation process, a first delay correction process (first delay corrector 702) that takes the communication delay into account is performed on the F target torque command value T _mf ^* or the F estimated torque T^ _mf to calculate an estimated torque delay correction value (F target torque command value delay correction value T' _mf ) (Equation (34)). Also, in the FB compensation process, an estimated value of the rotation state of the F drive motor 4f (F motor angular velocity estimated value ω^ mf ) is calculated based on the F target torque command value delay correction value T' _mf and the R estimated torque T^ _mr , with reference to the vehicle model ( _Gr (s), _Grr (s), and _Grrf ( _s )) of the electric vehicle 100. Furthermore, in the FB compensation process, a second delay correction process (second delay corrector 705) that takes the communication delay into account is performed on the detected value of the rotation state of the F drive motor 4f (F motor angular velocity detected value _ωmf ) to calculate a detected rotation state delay correction value (F motor angular velocity delay correction value _ω'mf ) (Equation (35)). Then, an F third torque command value _Tmf3 is calculated based on the F first torque command value _Tmf1 , the F motor angular velocity delay correction value _ω'mf , and the F motor angular velocity estimated value ω^ _mf .

As a result, when a vibration suppression control calculation for suppressing vibrations in the driving force transmission system is adopted as the torque command value correction process, it is possible to determine the input torque command value (F target torque command value T _mf ^* or F estimated torque T^ _mf ) and motor angular velocity estimated value ω^ _m taking into account communication delays between each motor controller. Therefore, it is possible to reduce the deviation between the motor angular velocity estimated value ω^ _m calculated from the vehicle model of the electric vehicle 100 and the motor angular velocity detected value ω _m equivalent to the actual value, improving the accuracy of the vibration suppression control calculation (particularly the FB compensation process) and preventing the occurrence of unnecessary vibration suppression compensation.

In addition, in the estimated torque calculation process of the first or third embodiment, an electric vehicle control method is provided in which the estimated torque T^ _m is calculated from the target torque command value Tm ^* by referring to a current response model of the first drive motor (the F drive motor 4f of the first embodiment, or the FR drive motor 4fr or FL drive motor _4fl of the third embodiment) (Equation (1)).

This allows for a more preferable calculation logic for the estimated torque T^ _m to be realized in the vibration damping control calculation for the electric vehicles 100 and 300 that use an interior permanent magnet synchronous motor as the first drive motor.

Furthermore, in the estimated torque calculation process of the second or third embodiment, the specified γ-axis current value i _γ ^* and the specified δ-axis current value i _δ ^* are calculated from the specified target torque value T _m ^* , and the estimated torque TM is calculated from the specified γ-axis current value i _γ ^* and the specified δ-axis current value i _δ ^* by referring to the magnetic flux response model and the current response model of the first drive motor (RR drive motor 4rr or RL drive motor _4rl of the second or third embodiment) (Equations (72) and (73)).

This allows for a more preferable calculation logic for the estimated torque T^ _m to be realized in the vibration damping control calculation for the electric vehicles 200, 300 that use an induction motor as the first drive motor.

In addition, in the estimated torque calculation process of the first or second embodiment, the d-axis current command value i _d ^{* ,} _q -axis current command value i _q ^* , and f-axis current command value i _f ^* are calculated from the target torque command value T m *, and the estimated torque T^ m is calculated from the d-axis current command value i d ^* , q-axis current command value i _q ^* , and f-axis current command value i f * by referring to the respective current response models of the rotor and stator of the first drive motor (R drive motor _{4r in the first embodiment, or F drive motor 4f in the} ^second embodiment) (equations (37) to (39)).

This allows for a more preferable calculation logic for the estimated torque T^ _m to be realized in the vibration suppression control calculation for the electric vehicles 100, 200 that use a wound-field synchronous motor as the first drive motor.

Furthermore, according to the FF compensation processing of the second or third embodiment, an estimated value of the torsional angular velocity (torsional angular velocity estimated value ω^ _d ) as the rotational state of the first drive motor is calculated based on the dynamic characteristics of the electric vehicles 200, 300, and the FF compensated torque command value (first torque command value T m1 ) is calculated by subtracting the value obtained by multiplying the torsional angular velocity estimated value ω^ _d by a predetermined gain k from the estimated torque (particularly the estimated torque delay correction value T^ _{' m} ) (Equation (67) and Figure 15).

This allows for more specific calculation logic to be implemented in the FF compensation process to determine the torque command value after FF compensation by referencing the torsional angular velocity, which is a specific parameter that indicates the rotational state of the first drive motor.

In the FF compensation process (701 in FIG. 7 or 1001 in FIG. 10) of the first embodiment, a linear filter (Equation (21) or Equation (24)) that reduces the natural vibration frequency component of the driving force transmission system of the first drive motor is applied to the target torque command value T _m ^* to calculate the FF compensated torque command value (first torque command value T _m1 ). In particular, the linear filter is determined based on the dynamic characteristics of the electric vehicle 100.

This makes it possible to calculate the first torque command value T _m1 using simple calculation logic that uses a linear filter determined in accordance with the dynamic characteristics of the electric vehicle 100 .

Furthermore, in the current command value calculation process (S404) of the first or third embodiment, the current command value i* (d-axis current command value i d * and q-axis current command value i q ^* ) is calculated based on the corrected torque command value (third torque command value _{T m3} ), the rotational state of the first drive motor (particularly, the motor angular velocity detection value _{ω m} ⁾ , and ^the power supply voltage (DC voltage value V _dc ).

This realizes a preferable calculation mode for determining the current command value i ^* from the third torque command value _Tm3 that has undergone vibration suppression control calculation in electric vehicles 100, 300 that have an interior permanent magnet synchronous motor as the first drive motor.

In the current command value calculation process of the second or third embodiment, the current command value i* (δ-axis current command value iδ ^{*) is calculated based on the target torque command value Tm*} _{, the} ^magnetic flux response model of the rotor of the first drive motor, the third torque command value _Tm3 , the motor angular velocity detection value _ωm , and the ^DC voltage value _Vdc .

This realizes a preferable calculation mode for determining the current command value i ^* from the third torque command value _Tm3 that has undergone vibration suppression control calculation in electric vehicles 200, 300 that use an induction motor as the first drive motor.

Furthermore, in the current command value calculation process of the first or second embodiment, the current command value _i* ⁽ q-axis current command value iq ^{*) is calculated based on the target torque command value Tm*} _, the respective current response models of the rotor and stator in the first drive motor, the third torque command value _Tm3 , the motor angular velocity detection value _ωm , ^and the DC voltage value _Vdc .

This realizes a preferable calculation mode for determining the current command value i ^* from the third torque command value _Tm3 that has undergone vibration suppression control calculation in electric vehicles 100, 200 that have a wound-field synchronous motor as the first drive motor.

Furthermore, according to each embodiment, each motor controller 31 is provided that functions as an electric vehicle control device suitable for the above-mentioned electric vehicle control method. In particular, each motor controller 31 functions as an estimated torque calculation processing unit that performs the above-mentioned estimated torque calculation process, an estimated torque output unit that performs the above-mentioned estimated torque output process, a torque command value correction unit that performs the above-mentioned torque command value correction process, and a current command value calculation unit that performs the above-mentioned current command value calculation process.

The above describes embodiments of the present invention, but these embodiments merely illustrate some of the application examples of the present invention, and are not intended to limit the technical scope of the present invention to the specific configurations of the above embodiments.

For example, the combinations of drive motor 4 types in the above embodiments are merely examples, and the electric vehicle control method of the present invention can be similarly applied to vehicles in which all drive motors 4 are the same type, or to vehicles with a combination of drive motor 4 types different from those in the above embodiments.

100, 200, 300 Electric vehicles 501, 802, 1202, 1702, 2002, 2201, 2301, 2702, 2802
Estimated torque calculation units 502, 803, 1203, 1703, 2202, 2302, 2703, 2803,
Vibration suppression control calculation unit 503, 801, 804, 1201, 1204, 1701, 1704, 2001, 2004, 2203, 2303, 2701, 2704, 2801, 2804
Current command value calculation section

Claims (11)

1. An electric vehicle control method for controlling a plurality of drive motors mounted on an electric vehicle, the method comprising the steps of: controlling each of the drive motors based on a current command value determined for each of the drive motors;
Each motor controller for controlling each of the drive motors includes:
executing an estimated torque calculation process for calculating each estimated torque based on each target torque command value according to the response characteristic and required output of each drive motor;
One motor controller,
an estimated torque output process for outputting the calculated first estimated torque to the other motor controller;
a torque command value correction process for correcting a target torque command value or the first estimated torque of a first drive motor based on a rotational state of the first drive motor to be controlled, to obtain a corrected torque command value;
a current command value calculation process for calculating the current command value of the first drive motor from the corrected torque command value;
In the torque command value correction process, a correction is performed on the rotation state of the first drive motor based on a second estimated torque calculated by the other motor controller, taking into account a communication delay between the motor controllers.
Electric vehicle control method. The electric vehicle control method according to claim 1,
The torque command value correction process includes:
an FF compensation process that calculates an FF-compensated torque command value by performing a feedforward calculation that suppresses vibrations in a driving force transmission system of the electric vehicle with respect to the target torque command value or the first estimated torque of the first drive motor;
an FB compensation process for calculating an FB compensated torque command value, which is the corrected torque command value, by performing a feedback calculation for suppressing vibration in the driving force transmission system using a detected value of the rotational state of the first drive motor with respect to the FF compensated torque command value,
In the FB compensation process,
calculating an estimated torque delay correction value by performing a first delay correction process on the target torque command value or the first estimated torque in consideration of the communication delay;
calculating an estimated value of a rotation state of the first drive motor based on the estimated torque delay correction value and the second estimated torque and with reference to a vehicle model of the electric vehicle;
calculating a detected rotational state delay correction value by performing a second delay correction process that takes the communication delay into consideration on the detected rotational state value of the first drive motor;
calculating the FB compensated torque command value based on the FF compensated torque command value, the detected rotational state delay correction value, and an estimated value of the rotational state of the first drive motor;
Electric vehicle control method. 3. The electric vehicle control method according to claim 2,
In the estimated torque calculation process,
calculating the first estimated torque from the target torque command value by referring to a current response model of the first drive motor;
Electric vehicle control method. 3. The electric vehicle control method according to claim 2,
In the estimated torque calculation process,
calculating a γ-axis current command value and a δ-axis current command value from the target torque command value;
calculating the first estimated torque from the specified γ-axis current value and the specified δ-axis current value by referring to a magnetic flux response model and a current response model of the first drive motor;
Electric vehicle control method. 3. The electric vehicle control method according to claim 2,
In the estimated torque calculation process,
calculating a d-axis current command value, a q-axis current command value, and an f-axis current command value from the target torque command value;
calculating the first estimated torque from the d-axis current command value, the q-axis current command value, and the f-axis current command value with reference to current response models of a rotor and a stator of the first drive motor, respectively;
Electric vehicle control method. The electric vehicle control method according to any one of claims 2 to 5,
In the FF compensation process,
calculating a torsional angular velocity estimate of a drive shaft of the first drive motor based on dynamic characteristics of the electric vehicle, and calculating the FF-compensated torque command value by multiplying the torsional angular velocity estimate by a predetermined gain and subtracting the result from the first estimated torque;
Electric vehicle control method. The electric vehicle control method according to any one of claims 2 to 5,
In the FF compensation process,
calculating the FF-compensated torque command value by applying a linear filter to the target torque command value, the linear filter reducing a natural vibration frequency component of a driving force transmission system of the first drive motor;
The linear filter is determined based on dynamic characteristics of the electric vehicle.
Electric vehicle control method. The electric vehicle control method according to any one of claims 2 to 7,
In the current command value calculation process,
calculating the current command value based on the feedback compensated torque command value, a rotation state of the first drive motor, and a power supply voltage;
Electric vehicle control method. The electric vehicle control method according to any one of claims 2 to 7,
In the current command value calculation process,
calculating the current command value based on the target torque command value, a magnetic flux response model of the rotor of the first drive motor, the feedback compensated torque command value, a rotation state of the first drive motor, and a power supply voltage;
Electric vehicle control method. The electric vehicle control method according to any one of claims 2 to 7,
In the current command value calculation process,
calculating the current command value based on the target torque command value, current response models of the rotor and the stator of the first drive motor, the feedback compensated torque command value, a rotation state of the first drive motor, and a power supply voltage;
Electric vehicle control method. An electric vehicle control device that controls each drive motor based on a current command value that is respectively determined for each drive motor in an electric vehicle equipped with the plurality of drive motors,
Each motor controller for controlling each of the drive motors includes:
an estimated torque calculation processing unit that calculates each estimated torque based on each target torque command value according to the response characteristic and required output of each of the drive motors;
One motor controller,
an estimated torque output unit that outputs the calculated first estimated torque to the other motor controller;
a torque command value correcting unit that calculates a corrected torque command value by correcting a target torque command value or the first estimated torque of a first drive motor based on a rotational state of the first drive motor that is a control target;
a current command value calculation unit that calculates the current command value of the first drive motor from the corrected torque command value,
The torque command value correction unit
correcting the rotation state of the first drive motor based on the second estimated torque calculated by the other motor controller, taking into account a communication delay between the motor controllers;
Electric vehicle control device.