Control method for electric vehicle and control device for electric vehicle

Abstract

To provide an electric vehicle control method and an electric vehicle control device which correct a difference in rotation speeds between driving wheels driven with different motors when such a difference occurs and facilitate conversion of a control state into a stable state with fluctuation of rotation speeds suppressed.SOLUTION: A first target rotation speed which is a target value of a rotation speed of a first motor is calculated on the basis of a rotation speed of a second motor. A second target rotation speed which is a target value of a rotation speed of the second motor is calculated on the basis of the rotation speed of the first motor. First rotation speed control torque which is torque that the first motor outputs is calculated on the basis of the first target rotation speed. Second rotation speed control torque which is torque that the second motor outputs is calculated on the basis of the second target rotation speed. Then, when the rotation speed of the first motor is larger than the same of the second motor, a first final torque instruction value which is a final torque instruction value with respect to the first motor is calculated on the basis of the first rotation speed control torque.SELECTED DRAWING: Figure 14

Description

[Technical Field]

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

[0002] Patent Document 1 relates to the control of an electric vehicle equipped with a first electric motor that drives the front wheels and a second electric motor that drives the rear wheels, and discloses that a slip state is detected based on the difference in rotational speed between the front and rear wheels, and that based on the slip state, output torque is transferred from the slipping wheel of the front or rear wheels to the non-slip wheel, while the rate of change in the output torque that is transferred is limited so as not to cause the non-slip wheel to slip. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 5835583 Summary of the Invention [Problem to be solved by the invention]

[0004] Electric vehicles equipped with multiple motors, each of which controls a drive wheel, are known. For example, there is a four-wheel-drive electric vehicle in which the front and rear wheels are driven by different motors. In such electric vehicles, the torque required to generate the required drive force, depending on the driver's accelerator operation, is distributed to each motor, thereby generating the required torque (drive force) for the entire electric vehicle. When a difference in rotation speed occurs between drive wheels driven by different motors and it is determined that one of the drive wheels is slipping, the torque that should be generated by the slipping drive wheel is additionally borne by the non-slip drive wheel. In this way, the electric vehicle generates the required torque while eliminating drive wheel slippage. In particular, the control disclosed in Patent Document 1 limits the amount of torque transfer, thereby preventing drive wheels that were not slipping from slipping due to torque transfer.

[0005] However, as described above, when attempting to correct a rotation speed difference between drive wheels driven by different motors, i.e., slippage, by transferring torque, it may be difficult for the rotation speed of the drive wheels to converge to a stable steady state. Specifically, repeated torque transfer between the drive wheels may result in an unstable control state in which the rotation speed of each drive wheel changes oscillatingly. Such an unstable control state may also occur when the rate of change (speed of change) of the transferred torque is limited. In other words, when torque that should be generated in a drive wheel with an excessive rotation speed is transferred to another drive wheel in order to correct a rotation speed difference between the drive wheels, the unstable control state described above may occur.

[0006] The present invention aims to provide a control method and a control device for an electric vehicle that, when a difference in rotation speed occurs between drive wheels driven by different motors, corrects the difference in rotation speed and makes it easy to converge to a stable control state in which fluctuations in rotation speed are suppressed. [Means for solving the problem]

[0007] One aspect of the present invention is a control method for an electric vehicle having first drive wheels driven by a first motor and second drive wheels driven by a second motor different from the first motor. In this control method, a total torque corresponding to a driving force required for the electric vehicle is determined, and a first base torque, which is the torque to be output by the first motor, and a second base torque, which is the torque to be output by the second motor, are calculated by allocating this total torque to the first motor and the second motor. Furthermore, a first rotation speed target value, which is a target value for the rotation speed of the first motor, is calculated based on the rotation speed of the second motor, and a second rotation speed target value, which is a target value for the rotation speed of the second motor, is calculated based on the rotation speed of the first motor. Furthermore, a first rotation speed control torque, which is the torque to be output by the first motor, is calculated based on the first rotation speed target value, and a second rotation speed control torque, which is the torque to be output by the second motor, is calculated based on the second rotation speed target value. Then, (a) when the rotation speed of the first motor is higher than the rotation speed of the second motor, a first final torque command value, which is a final torque command value for the first motor, is calculated based on the first rotation speed control torque, and a second final torque command value, which is a final torque command value for the second motor, is calculated by correcting the second basic torque based on a first torque deviation, which is the deviation between the first basic torque and the first rotation speed control torque. On the other hand, (b) when the rotation speed of the second motor is higher than the rotation speed of the first motor, a first final torque command value is calculated by correcting the first basic torque based on a second torque deviation, which is the deviation between the second basic torque and the second rotation speed control torque, and a second final torque command value is calculated based on the second rotation speed control torque. Then, the first motor and the second motor are driven based on the first final torque command value and the second final torque command value calculated as described above. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide a control method for an electric vehicle and a control device for an electric vehicle that, when a difference in rotation speed occurs between drive wheels driven by different motors, corrects the difference in rotation speed and makes it easy to converge to a stable control state in which fluctuations in rotation speed are suppressed. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is an explanatory diagram showing a schematic configuration of an electric vehicle. [Figure 2] FIG. 2 is a block diagram showing the configuration of the motor controller. [Figure 3] FIG. 3 is a graph showing an example of an accelerator opening-torque table. [Figure 4] FIG. 4 is a block diagram showing the configuration of the torque distribution calculation unit. [Figure 5] FIG. 5 is an explanatory diagram relating to the equation of motion of an electric vehicle. [Figure 6] FIG. 6 is a block diagram showing the configuration of the slip control calculation unit. [Figure 7] FIG. 7 is a block diagram showing the configuration of the slip determination unit. [Figure 8] FIG. 8 is a block diagram showing the configuration of the front / rear rotation difference target value calculation unit. [Figure 9] FIG. 9 is a block diagram showing the configuration of the front slip control calculation unit. [Figure 10] FIG. 10 is a block diagram showing the configuration of the rotation speed control unit in the front slip control calculation unit. [Figure 11] FIG. 11 is a block diagram showing the configuration of the disturbance torque estimation section in the front slip control calculation section. [Figure 12] FIG. 12 is a block diagram showing the configuration of the rear slip control calculation unit. [Figure 13] FIG. 13 is a block diagram showing the configuration of the rotation speed control unit in the rear slip control calculation unit. [Figure 14] FIG. 14 is a block diagram showing the configuration of the disturbance torque estimation section in the rear slip control calculation section. [Figure 15] FIG. 15 is a block diagram showing the configuration of the longitudinal torque command value calculation unit. [Figure 16] FIG. 16 is a time chart showing longitudinal acceleration and the like when the control of the first comparative example is executed. [Figure 17] FIG. 17 is a time chart showing longitudinal acceleration and the like when the control of the second comparative example is executed. [Figure 18] FIG. 18 is a time chart showing longitudinal acceleration and the like when the control according to this embodiment is executed. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0011] [First embodiment] Fig. 1 is an explanatory diagram showing the schematic configuration of an electric vehicle 10. As shown in Fig. 1, the electric vehicle 10 of this embodiment is a four-wheel drive vehicle in which front wheels 22 and rear wheels 32 are driven by different motors. The electric vehicle 10 includes a front drive system 11, a rear drive system 12, a battery 13, and a motor controller 14.

[0012] The front drive system 11 is a system that drives front wheels 22 by a front motor 21. In addition to the front motor 21 and the front wheels 22, the front drive system 11 is equipped with a front inverter 23, a rotation sensor 24, a current sensor 25, and the like.

[0013] The front motor 21 is, for example, a three-phase AC synchronous motor, and is driven by AC power input from the front inverter 23. The output torque of the front motor 21 generates torque (driving force) on the front wheels 22. Furthermore, when the drive shaft of the front motor 21 is rotated together with the front wheels 22, the front motor 21 generates so-called regenerative torque. This allows the front motor 21 to recover the kinetic energy of the electric vehicle 10 as electrical energy.

[0014] The front wheels 22 are drive wheels disposed at the front of the electric vehicle 10. The front wheels 22 are connected to the front motor 21 via a front reduction gear 26 and a drive shaft 27.

[0015] The front inverter 23 includes two pairs of switching elements for each phase of the front motor 21. The front inverter 23 turns these switching elements on and off in response to a PWM (Pulse Width Modulation) signal input from the motor controller 14. As a result, the front inverter 23 converts DC power supplied from the battery 13 into AC power and inputs it to the front motor 21 to drive the front motor 21. The switching elements that make up the front inverter 23 are power semiconductor elements, such as insulated gate bipolar transistors (IGBTs) and metal oxide semiconductor field effect transistors (MOS-FETs). During regenerative control, the front inverter 23 converts AC power generated by the front motor 21 into DC power and inputs it to the battery 13.

[0016] The rotation sensor 24 detects the rotor phase α of the front motor 21. f Detect the rotor phase α f is a so-called electrical angle [rad]. The rotation sensor 24 is, for example, a resolver or an encoder. The detected rotor phase α f is input to the motor controller 14.

[0017] The current sensor 25 detects the current i flowing through each phase of the front motor 21. uf ,i vf ,i wf These currents i uf ,i vf ,i wf is input to the motor controller 14.

[0018] The rear drive system 12 is a system that drives rear wheels 32 by a rear motor 31, and is configured symmetrically to the front drive system 11. Therefore, in addition to the rear motor 31 and rear wheels 32, the rear drive system 12 also includes a rear inverter 33, a rotation sensor 34, a current sensor 35, a rear reduction gear 36, a drive shaft 37, etc. Each of these components that make up the rear drive system 12 functions in the same way as each component of the front drive system 11. In other words, the rear wheels 32 are drive wheels located at the rear of the electric vehicle 10. The rotor phase of the rear drive system 12 detected by the rotation sensor 34 is "α r The current flowing through each phase of the rear motor 31 detected by the current sensor 35 is "i ur ,i vr ,i wr "

[0019] The battery 13 is provided in common to the front drive system 11 and the rear drive system 12, and supplies power to drive the front motor 21 and the rear motor 31. During regenerative control, the battery 13 is charged by the regenerative power generated by the front motor 21 and the rear motor 31.

[0020] The motor controller 14 is a control device for the electric vehicle 10. The motor controller 14 acquires various vehicle variables and generates PWM signals for driving the front motor 21 and the rear motor 31 based on these vehicle variables. The motor controller 14 then inputs the generated PWM signals to the front inverter 23 and the rear inverter 33, respectively, thereby driving the front motor 21 and the rear motor 31 in accordance with the vehicle variables.

[0021] The vehicle variables are parameters that represent the control state of the electric vehicle 10. For example, the motor controller 14 may use the rotor phase α of the front motor 21 as the vehicle variables. f and current i uf ,i vf ,i wf , the rotor phase α of the rear motor 31 r and current i ur ,i vr ,iwr In addition, the motor controller 14 acquires, for example, the accelerator opening A po , vehicle speed V, steering angle θ str [rad] and the voltage V of the battery 13 dc (not shown) are acquired as vehicle variables. po is a parameter that represents the amount of accelerator (not shown) operated by the driver. str are parameters that represent the direction and amount of steering of a steering wheel (not shown) by the driver. po , vehicle speed V, steering angle θ str , and the voltage V of the battery 13 dc These vehicle variables can be detected appropriately as needed by sensors (not shown) etc. Although the motor controller 14 of this embodiment acquires the vehicle variables directly from sensors etc., the motor controller 14 can also acquire some or all of the vehicle variables from another controller (computer) (not shown).

[0022] As described above, the electric vehicle 10 includes first drive wheels (e.g., front wheels 22) driven by a first motor (e.g., front motor 21), and second drive wheels (e.g., rear wheels 32) driven by a second motor (e.g., rear motor 31) different from the first motor. The specific configuration of the motor controller 14 that controls the first motor and the second motor, i.e., the front motor 21 and the rear motor 31, will be described below.

[0023] [Motor controller configuration] 2 is a block diagram showing the configuration of motor controller 14. Motor controller 14 is configured with one or more computers and is programmed to repeatedly execute the processing of each unit described below at a predetermined cycle. Specifically, motor controller 14 includes an input processing unit 41, a basic torque calculation unit 42, a slip control calculation unit 43, a vibration suppression control calculation unit 44, a current command value calculation unit 45, and a current control calculation unit 46 (motor drive control unit).

[0024] The input processing unit 41 acquires vehicle variables used for various control calculations, or executes input processing to calculate them.

[0025] For example, the input processing unit 41 may po , vehicle speed V, steering angle θ str , and the voltage V of the battery 13 dc The above information is acquired from a sensor or controller (not shown).

[0026] The input processing unit 41 also detects the current i of the front motor 21. uf ,i vf ,i wf and the current i of the rear motor 31 ur ,i vr ,i wr are acquired from the current sensors 25 and 35. In this embodiment, the current sensors 25 and 35 detect three-phase currents, but when the current sensors 25 and 35 detect two-phase currents among the three-phase currents, the input processing unit 41 calculates the current of the remaining one phase using the detected two-phase currents.

[0027] The input processing unit 41 also calculates the rotor phase α of the front motor 21. f and the rotor phase α of the rear motor 31 r are acquired from the rotation sensors 24 and 34, respectively. Then, the input processing unit 41 calculates the rotor phase α f and rotor phase α r By differentiating the rotor angular velocity ω of the front motor 21, f [rad / s] and the rotor angular velocity ω of the rear motor 31 r The input processing unit 41 calculates the rotor angular velocity ω f ,ω r is divided by the number of pole pairs of the front motor 21 and the rear motor 31 to obtain the rotation speed of the front motor 21 (hereinafter referred to as the front motor rotation speed) ω mf [rad / s], and the rotation speed of the rear motor 31 (hereinafter referred to as rear motor rotation speed) ω mrCalculate the front motor rotation speed ω [rad / s]. mf , and rear motor rotation speed ω mr is the mechanical angular velocity of each drive motor.

[0028] In the following, in various calculations, the front motor rotation speed ω mf and rear motor rotation speed ω mr However, the input processing unit 41 uses the front motor rotation speed ω mf and rear motor rotation speed ω mr is multiplied by the unit conversion coefficient (60 / 2π) to obtain the rotation speed N of the front motor 21. f [rpm] and the rotation speed N of the rear motor 31 r The input processing unit 41 can calculate the front motor rotation speed ω mf and rear motor rotation speed ω mr and the dynamic radii of the front wheels 22 and the rear wheels 32, the wheel rotation speeds of the front wheels 22 and the rear wheels 32 can be calculated. mf and rear motor rotation speed ω mr Instead of , the front motor rotation speed ω mf and rear motor rotation speed ω mr The rotation speed N is essentially equivalent to f ,N r Alternatively, the wheel rotation speeds of the front wheels 22 and rear wheels 32 can be used.

[0029] The basic torque calculation unit 42 calculates the total torque T corresponding to the driving force required for the electric vehicle 10. m1 * Calculate the total torque T m1 * to the front motor 21 and the rear motor 31. Specifically, the basic torque calculation unit 42 includes a total torque calculation unit 47 and a torque distribution calculation unit 48. The driving force required of the electric vehicle 10 is determined in accordance with the driver's operation, such as accelerator operation, and is the driving force that should be generated by the electric vehicle 10 as a whole.

[0030] The total torque calculation unit 47 calculates the front motor rotation speed ω mf and accelerator opening A po Based on the total torque T m1 * For example, the total torque calculation unit 47 calculates the front motor rotation speed ω mf and accelerator opening A po and total torque T m1 * Therefore, the total torque calculation unit 47 can calculate the front motor rotation speed ω by referring to the accelerator opening-torque table. mf and accelerator opening A po Total torque T according to m1 * Set.

[0031] The torque distribution calculation unit 48 calculates the total torque T m1 * to the front wheels 22 and the rear wheels 32, the front basic torque T mf * and rear basic torque T mr * Set the front basic torque T mf * is the total torque T m1 * The rear basic torque T is a target value for the torque that the front motor 21 should output. mr * is the total torque T m1 * This is a target value for the torque that the rear motor 31 should output.

[0032] The configuration of the basic torque calculation unit 42, that is, the configuration of the total torque calculation unit 47 and the torque distribution calculation unit 48, will be described in detail later.

[0033] The slip control calculation unit 43 calculates the front basic torque T mf * and rear basic torque T mr * and the front motor rotation speed ω mfand rear motor rotation speed ω mr Based on this, the front final torque command value T mf-f2 * and rear final torque command value T mr-f2 * Calculate the front final torque command value T mf-f2 * is the final torque command value for the front motor 21. The rear final torque command value T mr-f2 * is the final torque command value for the rear motor 31. In particular, the slip control calculation unit 43 eliminates or suppresses slip of the front wheels 22 and the rear wheels 32 and also controls the front motor rotation speed ω mf and rear motor rotation speed ω mr By this slip control calculation process, the slip control calculation unit 43 executes slip control calculation processing to suppress fluctuations in the front final torque command value T mf-f2 * and rear final torque command value T mr-f2 * The configuration of the slip control calculation unit 43 will be described in detail later.

[0034] In this embodiment, the "slip" refers to the front motor rotation speed ω mf and rear motor rotation speed ω mr This refers to a state in which there is a difference between the front and rear wheels 22 and 32. Therefore, even if the front and rear wheels 22 and 32 are gripping the road surface and both wheels 22 and 32 are generating driving force, slippage can occur. In this embodiment, even if the front wheels 22 or the rear wheels 32 are slipping, it is assumed that at least one of the front wheels 22 or the rear wheels 32 is gripping the road surface. In the following, it is assumed that the driving wheel with a relatively high rotation speed is in a slipping state. For example, if the front motor rotation speed ω mf is the rear motor rotation speed ω mr When the value is greater than 0.05, the front wheels 22 are slipping.

[0035] The vibration suppression control calculation unit 44 calculates the front motor rotation speed ω mf and rear motor rotation speed ω mrBased on this, the front final torque command value T mf-f2 * and rear final torque command value T mr-f2 * Specifically, the vibration suppression control calculation unit 44 calculates the front motor rotation speed ω using the transfer characteristics from the torque input to each motor to the rotation speed of each motor. mf and rear motor rotation speed ω mr As a result, the vibration suppression control calculation unit 44 feeds back the front final torque command value T mf-f2 * and rear final torque command value T mr-f2 * The vibration damping control calculation unit 44 compensates for components such as torsional vibration of the drive shafts 27, 37 included in the vibration damping control calculation unit 44. More specifically, the vibration damping control calculation unit 44 executes a known vibration damping control process, for example, as described in Japanese Patent Application Laid-Open No. 2003-009566. Note that when the electric vehicle 10 does not have the drive shafts 27, 37, or when the torsional vibration of the drive shafts 27, 37 is suppressed by a mechanical mechanism or the like, the vibration damping control calculation may be omitted.

[0036] The current command value calculation unit 45 calculates the dq-axis current command value i df * ,i qf * (not shown), and the dq-axis current command value i dr * ,i qr * Specifically, the current command value calculation unit 45 holds, for example, a front current command value table (not shown). The front current command value table contains a front final torque command value T mf-f2 * , front motor rotation speed ω mf , and the voltage V of the battery 13 dc and the dq-axis current command value i of the front motor 21. df * ,i qf *This is a look-up table in which the front current command value T mf-f2 * and the front motor rotation speed ω mf and the voltage V of battery 13 dc Based on this, the dq-axis current command value i df * ,i qf * Similarly, the current command value calculation unit 45 holds, for example, a rear current command value table (not shown). The rear current command value table calculates the rear final torque command value T mr-f2 * , rear motor rotation speed ω mr , and the voltage V of the battery 13 dc and the dq-axis current command value i of the rear motor 31. dr * ,i qr * This is a look-up table in which the rear final torque command value T mr-f2 * and rear motor rotation speed ω mr and the voltage V of battery 13 dc Based on this, the dq-axis current command value i dr * ,i qr * When the vibration suppression control calculation process is performed, the front final torque command value T mf-f2 * and rear final torque command value T mr-f2 * The value after vibration suppression control calculation processing is used for .

[0037] The current control calculation unit 46 executes current control calculation processing to calculate each PWM signal to be input to the front inverter 23 and the rear inverter 33.

[0038] Specifically, first, the current control calculation unit 46 calculates the current i of the front motor 21. uf ,i vf ,i wf and rotor phase α f Based on this, the dq-axis current i of the front motor 21 df ,i qf Similarly, the current control calculation unit 46 calculates the current i of the rear motor 31. ur ,i vr ,i wr and rotor phase α r Based on this, the dq-axis current i of the rear motor 31 is calculated. dr ,i qr (not shown) is calculated.

[0039] Next, the current control calculation unit 46 calculates the dq-axis current i df ,i qf and the dq-axis current command value i df * ,i qf * Based on the deviation of df * ,v qf * Similarly, the current control calculation unit 46 calculates the dq-axis current i dr ,i qr and the dq-axis current command value i dr * ,i qr * Based on the deviation of dr * ,v qr * (not shown) is calculated. The dq-axis voltage command value v df * ,v qf * , and the dq-axis voltage command value v of the rear motor 31 dr * ,v qr * In the calculation of (a), decoupling control may be applied to suppress currents caused by interference between the d and q axes.

[0040] Thereafter, the current control calculation unit 46 calculates the dq-axis voltage command value v df * ,v qf * and rotor phase α f Based on this, the voltage command value v for each phase of the front motor 21 is calculated. uf * ,v vf * ,v wf * Similarly, the current control calculation unit 46 calculates the dq-axis voltage command value v of the rear motor 31. dr * ,v qr * and rotor phase α r Based on this, the voltage command value v for each phase of the rear motor 31 is calculated. ur * ,v vr * ,v wr * (not shown) is calculated.

[0041] The current control calculation unit 46 calculates the voltage command value v for each phase of the front motor 21. uf * ,v vf * ,v wf * and the voltage of battery 13, V dc Similarly, the current control calculation unit 46 calculates the voltage command value v for each phase of the rear motor 31. ur * ,v vr * ,v wr * and the voltage of battery 13, V dc The PWM signal to be input to the rear inverter 33 is calculated based on the above.

[0042] The front inverter 23 and the rear inverter 33 open and close the switching elements in response to the PWM signals calculated as described above. As a result, the front motor 21 and the rear motor 31 are controlled in response to the front final torque command value Tmf-f2 * and rear final torque command value T mr-f2 * The motor is driven to output a torque corresponding to

[0043] [Configuration of basic torque calculation section] FIG. 3 is a graph showing an example of an accelerator opening-torque table. The accelerator opening-torque table is determined in advance through experiments, simulations, or the like. In this embodiment, the total torque calculation unit 47 refers to this accelerator opening-torque table to calculate the front motor rotation speed ω mf and accelerator opening A po Based on the total torque T m1 * Set.

[0044] Fig. 4 is a block diagram showing the configuration of the torque distribution calculation unit 48. As shown in Fig. 4, the torque distribution calculation unit 48 includes a total torque limiting unit 51, a front wheel distribution gain multiplication unit 52, and a rear wheel distribution gain multiplication unit 53.

[0045] The total torque limiting unit 51 is configured to limit the front motor rotation speed ω mf rate of change of rear motor rotation speed ω mr Based on the rate of change of the total torque T m1 * Specifically, the total torque limiting unit 51 limits the front motor rotation speed ω mf and rear motor rotation speed ω mr Then, the front motor rotation speed ω mf is the rear motor rotation speed ω mr When the total torque limiting unit 51 is set to the rear motor rotation speed ω mr The total torque T m1 * On the other hand, the rear motor rotation speed ω mr is the front motor rotation speed ω mf When the front motor rotation speed ω is greater than ω , the total torque limiting unit 51 mf The total torque T m1 *That is, when the front wheels 22 slip, the total torque limiting unit 51 limits the total torque T m1 * When the rear wheels 32 slip, the total torque T is limited based on the rate of change of the rotation speed of the front wheels 22 that are not slipping. m1 * Limit.

[0046] In this embodiment, the total torque limiting unit 51 is configured to limit the front motor rotation speed ω mf or rear motor rotation speed ω mr When the magnitude of the differential value of becomes equal to or greater than a predetermined threshold value β (not shown), the total torque T m1 * That is, the total torque limiting unit 51 limits the total torque T m1 * When neither the front wheels 22 nor the rear wheels 32 are slipping, or when the front wheels 22 or the rear wheels 32 are slipping but the slippage is not steep, the total torque T m1 * The threshold value β is determined in advance by experiment, simulation, or the like. The total torque limiting unit 51 also limits the front motor rotation speed ω mf or rear motor rotation speed ω mr The magnitude of the differential value of is multiplied by a predetermined gain γ (not shown) to obtain the total torque T m1 * By subtracting from the m1 * is limited, and the total torque after limiting T m2 * The gain γ is determined in advance by experiment, simulation, or the like.

[0047] The front wheel distribution gain multiplication unit 52 multiplies the total torque T m2 * (Total torque T m1 * If there is no limit to the total torque T m1* ) with front wheel distribution gain K f By multiplying the front basic torque T mf * The front wheel distribution gain Kf is determined in advance between "0" and "1" according to the settings of the control mode of the electric vehicle 10 and the like.

[0048] The rear wheel distribution gain multiplication unit 53 multiplies the total torque T m2 * (Total torque T m1 * If there is no limit to the total torque T m1 * ) for rear wheel distribution gain "1-K f " by multiplying the rear basic torque T mr * Calculate the following.

[0049] [Configuration of slip control calculation section] FIG. 5 is an explanatory diagram of the equations of motion of the electric vehicle 10. As shown in FIG. 5, the torque transmission system of the electric vehicle 10 is modeled. Therefore, the equations of motion of the electric vehicle 10 are expressed by the following equations (1) to (4). Furthermore, the parameters used in FIG. 5 and the equations of motion are as follows. The auxiliary symbols "f" and "r" for each parameter represent "front" and "rear," respectively. Note that the equations of motion below do not take into account torque due to disturbances such as torsion of the drive shafts 27 and 37 and reaction forces from the road surface (hereinafter referred to as disturbance torque).

[0050]

number

[0051] J mf ,J mr : Motor inertia J wf ,J wr : Drive shaft inertia (for one shaft) N f , N r :Overall gear ratio ω mf,ω mr :Motor rotation speed T mf ,T mr :Motor torque T df ,T dr : Drive shaft torque

[0052] According to the equation of motion above, the front motor torque T mf Front motor rotation speed ω mf Transfer characteristics G pf (s), and rear motor torque T mr to rear motor rotation speed ω mr Transfer characteristics G pr (s) is expressed by the following equations (5) to (7). pf (s) and transfer characteristic G pr It is constructed using (s), where "s" is the Laplace operator.

[0053]

number

[0054] Fig. 6 is a block diagram showing the configuration of the slip control calculation unit 43. As shown in Fig. 6, the slip control calculation unit 43 includes a slip determination unit 61, a front / rear rotation difference target value calculation unit 62, a front slip control calculation unit 63, a rear slip control calculation unit 64, and a front / rear torque command value calculation unit 65.

[0055] The slip determination unit 61 determines the front motor rotation speed ω mf and rear motor rotation speed ω mr Based on this, the slip determination unit 61 determines whether slip has occurred in the front wheels 22 or the rear wheels 32. The slip determination unit 61 sets the result of this determination as a front slip flag SF f and rear slip flag SF r and outputs it to the longitudinal torque command value calculation unit 65.

[0056] The front-rear rotation difference target value calculation unit 62 calculates the steering rotation angle θ strBased on the vehicle speed V, the target rotation difference ω mfr * The target rotation difference between the front and rear wheels ω mfr * is the difference in rotation speed between the front wheel 22 and the rear wheel 32 (hereinafter referred to as the differential rotation ω mfr ) and the differential rotation ω that should be generated depending on the steering situation of the electric vehicle 10. mfr For example, the steering angle θ str is zero and the electric vehicle 10 is traveling straight, the target front-rear rotation difference value ω mfr * is zero. When the electric vehicle 10 is turning to the left or right, the target front-rear rotation difference value ω mfr * is the steering rotation angle θ str and has a value according to the vehicle speed V. The target rotation difference between the front and rear mfr * are input to a front slip control calculation unit 63 and a rear slip control calculation unit 64.

[0057] The front slip control calculation unit 63 calculates the front motor rotation speed ω mf and rear motor rotation speed ω mr and the target rotation difference between the front and rear wheels ω mfr * and, based on the front slip control torque T mf-slip * Calculate the front slip control torque T mf-slip * In principle, the front motor rotation speed ω mf The rear motor rotation speed ω mr This represents the target value for the output torque of the front motor 21 when the front slip control torque T mf-slip * When the front motor 21 is driven so as to have an output torque expressed as mf is the rear motor rotation speed ω mr Therefore, for example, when the front wheels 22 slip, the front slip control torque T mf-slip *When the front motor 21 is controlled to output a torque equivalent to the front slip control torque T mf-slip * is input to the longitudinal torque command value calculation unit 65.

[0058] The rear slip control calculation unit 64 calculates the front motor rotation speed ω mf and rear motor rotation speed ω mr and the target rotation difference between the front and rear wheels ω mfr * and, based on the rear slip control torque T mr-slip * Calculate the rear slip control torque T mr-slip * In principle, the rear motor rotation speed ω mr Front motor rotation speed ω mf This represents the target value for the output torque of the rear motor 31 in the case where the rear slip control torque Tmr-slip* is made to match the rear slip control torque Tmr-slip*. In other words, when the rear motor 31 is driven so as to achieve the output torque represented by the rear slip control torque Tmr-slip*, the rear motor rotation speed ωmr will substantially match the front motor rotation speed ωmf. Therefore, when the rear wheels 32 slip, the rear slip control torque T mr-slip * When the rear motor 31 is controlled to output a torque corresponding to the rear slip control torque T mr-slip * is input to the longitudinal torque command value calculation unit 65.

[0059] The front motor rotation speed ω mf and rear motor rotation speed ω mr Regarding "matching", the target rotation difference between the front and rear mfr * When is zero, the front motor rotation speed ω mf The rear motor rotation speed ω mr or the rear motor rotation speed ω mr Front motor rotation speed ω mf The target front-rear rotation difference value ω mfr* If has a non-zero value, the above "match" means that the front motor rotation speed ω mf or rear motor rotation speed ω mr , the target rotation difference between the front and rear wheels ω mfr * The differential rotation ω corresponds to mfr For example, the front motor rotation speed ω mf , rear motor rotation speed ω mr Based on ω mr +|ω mfr * | or ω mr -|ω mfr * The state where the front motor rotation speed ω is substantially equal to mf The rear motor rotation speed ω mr The rear motor rotation speed ω mr Front motor rotation speed ω mf The same is true when "matching" with

[0060] The front and rear torque command value calculation unit 65 calculates the front basic torque T mf * and rear basic torque T mr * and front slip flag SF f and rear slip flag SF r and front slip control torque T mf-slip * and rear slip control torque T mr-slip * Based on this, the front final torque command value T mf-f2 * and rear final torque command value T mr-f2 * Calculate the following.

[0061] The specific configuration of each of the above-mentioned components constituting the slip control calculation unit 43 will be described in detail below.

[0062] [Specific configuration of the slip determination unit] 7 is a block diagram showing the configuration of the slip determination unit 61. As shown in FIG.

[0063] The differential rotation calculation unit 71 calculates the front motor rotation speed ω mf and rear motor rotation speed ω mr The deviation of the rotation, i.e., the differential rotation ω mfr In this embodiment, the differential rotation calculation unit 71 calculates the front motor rotation speed ω mf to rear motor rotation speed ω mr By subtracting the difference rotation ω mfr Calculate the difference rotation ω mfr is input to the slip flag calculation unit 72.

[0064] The slip flag calculation unit 72 calculates the differential rotation ω mfr and a predetermined rotation speed threshold ω m-th Based on the front slip flag SF f and rear slip flag SF r Specifically, the slip flag calculation unit 72 calculates the front slip flag SF according to the following equations (8) and (9): f and rear slip flag SF r Calculates the front slip flag SF f and rear slip flag SF r where "1" represents "slip" and "0" represents "non-slip."

[0065]

number

[0066] As shown in equations (8) and (9), the front motor rotation speed ω mf is the rear motor rotation speed ω mr is larger than the difference rotation ω mfr The absolute value of the rotation speed threshold ω m-th When the value is equal to or greater than the front slip flag SF f is "1" (slip) and rear slip flag SF rbecomes "0" (non-slip). Also, the rear motor rotation speed ω mr is the front motor rotation speed ω mf is larger than the difference rotation ω mfr The absolute value of the rotation speed threshold ω m-th When the front slip flag SF f is "0" (non-slip) and the rear slip flag SF r becomes "1" (slip). In other words, the differential rotation ω mfr The absolute value of the rotation speed threshold ω m-th When the difference rotation ω mfr Depending on the sign of mf is the rear motor rotation speed ω mr or rear motor rotation speed ω mr is the front motor rotation speed ω mf is determined to be greater than

[0067] In this embodiment, the rotation speed threshold ω m-th is the target rotation difference between the front and rear wheels ω mfr * The target front-rear rotation difference value ω mfr * The larger the rotation speed threshold ω m-th is set to be large. For example, the rotation speed threshold ω m-th is a predetermined reference value, and the target front-rear rotation difference value ω mfr * In this way, the rotation speed threshold ω m-th By making variable the rotation speed threshold ω m-th is an appropriate value according to the turning state of the electric vehicle 10. m-th may be a fixed value determined in advance through an experiment, a simulation, or the like.

[0068] [Specific configuration of the front / rear rotation difference target value calculation unit] 8 is a block diagram showing the configuration of the front / rear rotation difference target value calculation unit 62. As shown in FIG. 8, the front / rear rotation difference target value calculation unit 62 includes a first multiplication unit 81 and a second multiplication unit .

[0069] The first multiplication unit 81 multiplies the steering rotation angle θ str and multiply it by the vehicle speed V.

[0070] The second multiplication unit 82 multiplies the steering rotation angle θ str and the vehicle speed V, and then the gain K θV By multiplying by , the target rotation difference between the front and rear mfr * Calculate the gain K θV is determined in advance by experiment, simulation, or the like.

[0071] In this embodiment, the front-rear rotation difference target value calculation unit 62 includes the first multiplication unit 81 and the second multiplication unit 82 as described above, but is not limited to this. str , vehicle speed V, and yaw rate sensor value (not shown) are input, and the corresponding front-rear rotation difference target value ω mfr * The information may be stored in a map or the like.

[0072] [Specific configuration of the front slip control calculation unit] Fig. 9 is a block diagram showing the configuration of the front slip control calculation unit 63. As shown in Fig. 9, the front slip control calculation unit 63 includes a front rotation speed target value calculation unit 91 (first or second rotation speed target value calculation unit), a rotation speed control unit 92, a disturbance torque estimation unit 93, and a disturbance torque compensation unit 94.

[0073] The front rotation speed target value calculation unit 91 calculates the rear motor rotation speed ω mr Based on the front motor rotation speed ω mf The front rotation speed target value ω mf * In this embodiment, the front rotation speed target value calculation unit 91 calculates the rear motor rotation speed ω mr The target rotation difference between the front and rear is ω mfr * By adding mf* This front rotation speed target value ω mf * is the front motor rotation speed ω mf The rear motor rotation speed ω mr The electric vehicle 10 is traveling straight, and the target rotation speed difference value ω mfr * When is zero, the front rotation speed target value ω mf * is the rear motor rotation speed ω mr Front rotation speed target value ω mf * is input to the rotation speed control unit 92.

[0074] The steering rotation angle θ str is equal to or smaller than a predetermined threshold value and it is determined that the electric vehicle 10 is traveling substantially straight, the front rotation speed target value calculation unit 91 calculates the front / rear rotation speed target value ω mfr * By omitting the addition of the front motor rotation speed ω mf and rear motor rotation speed ω mr In this case, the straight-line stability of the electric vehicle 10 is improved near the center of the steering.

[0075] The rotation speed control unit 92 (first or second rotation speed control torque calculation unit) calculates the front motor rotation speed ω mf and the front rotation speed target value ω mf * and, based on the front rotation speed control torque T ωf Calculate the front rotation speed control torque T ωf is the front motor rotation speed ω mf The rear motor rotation speed ω mr This is the target value of the torque that the front motor 21 should output when the rotational speed of the front motor 21 coincides with the rotational speed of the front motor 21.

[0076] Fig. 10 is a block diagram showing the configuration of the rotation speed control unit 92 in the front slip control calculation unit 63. As shown in Fig. 10, the rotation speed control unit 92 includes a rotation speed deviation calculation unit 101 and a front model matching compensation unit 102.

[0077] The rotation speed deviation calculation unit 101 calculates the front motor rotation speed ω mf and the front rotation speed target value ω mf * The deviation of the front rotation speed Δω mf Calculate the front rotation speed deviation Δω mf is input to the front model matching compensation unit 102.

[0078] The front model matching compensation unit 102 calculates the front rotation speed deviation Δω mf , the transfer characteristic G pf By filtering with a filter consisting of (s) and low-pass filter R1(s), the front rotation speed control torque T ωf The front model matching compensation unit 102 calculates, for example, R1(s) / {G pf (s)(1-R1(s))}. The time constant of the low-pass filter R1(s) is determined in advance by experiment, simulation, or the like.

[0079] The disturbance torque estimation unit 93 (see FIG. 9) estimates the disturbance torque acting on the front motor 21 (hereinafter referred to as the front disturbance torque T df In this embodiment, the disturbance torque estimation unit 93 calculates the front motor rotation speed ω mf and front slip control torque T mf-slip * (previous value) is used as input, and the front disturbance torque T df Output.

[0080] Fig. 11 is a block diagram showing the configuration of the disturbance torque estimating section 93 in the front slip control calculating section 63. As shown in Fig. 11, the disturbance torque estimating section 93 includes a first front motor torque estimating section 111, a second front motor torque estimating section 112, and a front disturbance torque calculating section 113.

[0081] The first front motor torque estimation unit 111 estimates the front motor rotation speed ω mf , the transfer characteristic G pf (s) and a low-pass filter H(s) to obtain the first front motor torque estimate T mf1 The first front motor torque estimation unit 111 calculates (estimates) H(s) / G pf (s). The low-pass filter H(s) is expressed by the following equation (10). The time constant τ V is determined in advance by experiment, simulation, or the like.

[0082]

number

[0083] The second front motor torque estimation unit 112 estimates the front slip control torque T mf-slip * (previous value) is filtered by a low-pass filter H(s) to obtain the second front motor torque estimate T mf2 Calculate (estimate) ^.

[0084] The front disturbance torque calculation unit 113 calculates the first front motor torque estimate T mf1 ^ and the estimated torque of the second front motor T mf2 ^ Based on the front disturbance torque T df In this embodiment, the front disturbance torque calculation unit 113 calculates the first front motor torque estimate T mf1 ^ to the second front motor torque estimate T mf2 By subtracting ^, the front disturbance torque T dfCalculate the following.

[0085] The disturbance torque compensation unit 94 (see FIG. 9) calculates the front rotation speed control torque T ωf and front disturbance torque T df Based on this, the front disturbance torque T df By compensating for this, the front slip control torque T mf-slip * Specifically, the disturbance torque compensation unit 94 calculates the front rotation speed control torque T ωf from the front disturbance torque T df By subtracting the front disturbance torque T df The compensated front slip control torque T mf-slip * Calculate the following.

[0086] [Specific configuration of rear slip control calculation unit] Fig. 12 is a block diagram showing the configuration of the rear slip control calculation unit 64. As shown in Fig. 12, the rear slip control calculation unit 64 includes a rear rotation speed target value calculation unit 121 (first or second rotation speed target value calculation unit), a rotation speed control unit 122 (first or second rotation speed control torque calculation unit), and a disturbance torque estimation unit 123. These components constituting the rear slip control calculation unit 64 are configured symmetrically to the components constituting the front slip control calculation unit 63, except that parameters for the rear drive system 12 are used.

[0087] The rear rotation speed target value calculation unit 121 calculates the front motor rotation speed ω mf Based on this, the rear motor rotation speed ω mr The target rear rotation speed ω mr * In this embodiment, the rear rotation speed target value calculation unit 121 calculates the front motor rotation speed ω mf The target rotation difference between the front and rear is ω mfr * By subtracting the rear rotation speed target value ω mr * This rear rotation speed target value ω mr *is the rear motor rotation speed ω mr Front motor rotation speed ω mf The electric vehicle 10 is traveling straight, and the target rotation speed difference value ω mfr * When is zero, the rear rotation speed target value ω mr * is the front motor rotation speed ω mf The target rear rotation speed ω mr * is input to the rotation speed control unit 122.

[0088] The steering rotation angle θ str is equal to or smaller than a predetermined threshold value and it is determined that the electric vehicle 10 is traveling substantially straight, the rear rotation speed target value calculation unit 121 calculates the front / rear rotation speed target value ω mfr * By omitting the subtraction of the front motor rotation speed ω mf and rear motor rotation speed ω mr In this case, the straight-line stability of the electric vehicle 10 is improved near the center of the steering.

[0089] The rotation speed control unit 122 controls the rear motor rotation speed ω mr and the target rear rotation speed ω mr * and, based on the rear rotation speed control torque T ωr Calculate the rear rotation speed control torque T ωr is the rear motor rotation speed ω mr Front motor rotation speed ω mf This is the target value of the torque that the rear motor 31 should output when the rotational speed of the rear motor 31 coincides with the rotational speed of the rear motor 31.

[0090] Fig. 13 is a block diagram showing the configuration of the rotation speed control unit 122 in the rear slip control calculation unit 64. As shown in Fig. 13, the rotation speed control unit 122 includes a rotation speed deviation calculation unit 131 and a rear model matching compensation unit 132. These units have a symmetrical configuration corresponding to the units of the rotation speed control unit 92 in the front slip control calculation unit 63, except that parameters for the rear drive system 12 are used.

[0091] The rotation speed deviation calculation unit 131 calculates the rear motor rotation speed ω mr and the target rear rotation speed ω mr * The rear rotation speed deviation Δω mr Calculate the rear rotation speed deviation Δω mr is input to the rear model matching compensation unit 132.

[0092] The rear model matching compensation unit 132 calculates the rear rotation speed deviation Δω mr , the transfer characteristic G pr By filtering with a filter consisting of (s) and low-pass filter R1(s), the rear rotation speed control torque T ωr The rear model matching compensation unit 132 calculates, for example, R1(s) / {G pr (s)(1-R1(s))}.

[0093] The disturbance torque estimation unit 123 (see FIG. 12) estimates the disturbance torque acting on the rear motor 31 (hereinafter referred to as rear disturbance torque T dr In this embodiment, the disturbance torque estimation unit 123 calculates the rear motor rotation speed ω mr and rear slip control torque T mr-slip * (previous value) is input, and the rear disturbance torque T dr Output.

[0094] Fig. 14 is a block diagram showing the configuration of the disturbance torque estimator 123 in the rear slip control calculator 64. As shown in Fig. 14, the disturbance torque estimator 123 includes a first rear motor torque estimator 141, a second rear motor torque estimator 142, and a rear disturbance torque calculator 143. These components are configured symmetrically to correspond to the respective components of the disturbance torque estimator 93 in the front slip control calculator 63, except that parameters for the rear drive system 12 are used.

[0095] The first rear motor torque estimation unit 141 estimates the rear motor rotation speed ωmr based on the transfer characteristic G pr (s) and a low-pass filter H(s) to obtain the first rear motor torque estimate T mr1 The first rear motor torque estimation unit 141 calculates (estimates) H(s) / G pr It is represented by (s).

[0096] The second rear motor torque estimation unit 142 estimates the rear slip control torque T mr-slip * (previous value) is filtered by a low-pass filter H(s) to obtain the second rear motor torque estimate T mr2 Calculate (estimate) ^.

[0097] The rear disturbance torque calculation unit 143 calculates the first rear motor torque estimate T mr1 ^ and estimated second rear motor torque T mr2 ^ Based on the rear disturbance torque T dr In this embodiment, the rear disturbance torque calculation unit 143 calculates the first rear motor torque estimate value T mr1 ^ to the second rear motor torque estimate T mr2 By subtracting ^, the rear disturbance torque T dr Calculate the following.

[0098] The disturbance torque compensation unit 124 (see FIG. 12) calculates the rear rotation speed control torque T ωr and rear disturbance torque T dr Based on this, the rear disturbance torque T dr By compensating for the rear slip control torque T mr-slip * Specifically, the disturbance torque compensation unit 124 calculates the rear rotation speed control torque T ωr Rear disturbance torque T dr By subtracting the rear disturbance torque T dr The compensated rear slip control torque T mr-slip * Calculate the following.

[0099] [Specific configuration of the front / rear torque command value calculation unit] 15 is a block diagram showing the configuration of the front / rear torque command value calculation unit 65. As shown in FIG. 15, the front / rear torque command value calculation unit 65 includes a front final torque command value calculation unit 151 and a rear final torque command value calculation unit 152.

[0100] The front final torque command value calculation unit 151 includes a rotation speed control torque limiting unit 161 (LIM), a torque command value switching unit 162, a correcting unit 163, a torque deviation calculation unit 164, and a change rate limiting unit 165 (rate limit).

[0101] The rotation speed control torque limiting unit 161 is configured to limit the front slip control torque T mf-slip * But the front basic torque T mf * When the front slip control torque T mf-slip * The value of the front basic torque T mf * That is, the rotation speed control torque limiting unit 16 limits the front slip control torque T mf-slip * Front basic torque T mf * Restrict to the following:

[0102] The torque command value switching unit 162 sets the front slip flag SF f Based on the front base torque T mf * or front slip control torque T mf-slip * Either of these is used as the first front final torque command value T mf-f1 * Front slip flag SF f is "0" and the front wheels 22 are in a non-slip state, the torque command value switching unit 162 sets the front basic torque T mf * is the first front final torque command value T mf-f1 *On the other hand, when the front slip flag SFf is "1" and the front wheels 22 are in a slipping state, the torque command value switching unit 162 outputs the front slip control torque T mf-slip * is the first front final torque command value T mf-f1 * Output as

[0103] The correction unit 163 calculates the rear basic torque T mr * and rear slip control torque T mr-slip * The rear torque deviation ΔT r Based on this, the first front final torque command value T mf-f1 * By correcting the (second) front final torque command value T mf-f2 * In this embodiment, the correction unit 163 calculates the first front final torque command value T mf-f1 * Rear torque deviation ΔT r By adding mf-f2 * Calculate the following.

[0104] The torque deviation calculation unit 164 calculates the front basic torque T mf * and the first front final torque command value T mf-f1 * Front torque deviation ΔT f In this embodiment, the torque deviation calculation unit 164 calculates the front basic torque T mf * to the first front final torque command value T mf-f1 * By subtracting the front torque deviation ΔT f Calculate the front torque deviation ΔT f is input to the correction unit 168 of the rear final torque command value calculation unit 152 via the change rate limiting unit 165. That is, the front torque deviation ΔT frepresents the amount of torque transferred from the front motor 21 (front wheels 22) to the rear motor 31 (rear wheels 32).

[0105] The change rate limiting unit 165 is configured to limit the front torque deviation ΔT f is input to the correction unit 168 of the rear final torque command value calculation unit 152, the front torque deviation ΔT f Limits the rate of change of front torque deviation ΔT f The limit value (upper limit value) for the rate of change of the front torque deviation ΔT is determined in advance by experiment, simulation, or the like. f This prevents the rear wheels 32 from slipping due to a torque shift equivalent to the torque shift.

[0106] The rear final torque command value calculation unit 152 includes a rotation speed control torque limiting unit 166 (LIM), a torque command value switching unit 167, a correction unit 168, a torque deviation calculation unit 169, and a change rate limiting unit 165 (rate limit). Each of these units has a symmetrical configuration corresponding to each unit of the front final torque command value calculation unit 151, except that parameters for the rear drive system 12 are used.

[0107] The rotation speed control torque limiting unit 166 limits the rear slip control torque T mr-slip * But the rear basic torque T mr * When the rear slip control torque T mr-slip * The value of the rear basic torque T mr * That is, the rotation speed control torque limiting unit 16 limits the rear slip control torque T mr-slip * Rear basic torque T mr * Restrict to the following:

[0108] The torque command value switching unit 167 sets the rear slip flag SF r Based on the rear base torque T mr *or rear slip control torque T mr-slip * Either of these is used as the first rear final torque command value T mr-f1 * When the rear slip flag SFr is "0" and the rear wheels 32 are not in a slip state, the torque command value switching unit 167 outputs the rear basic torque T mr * is the first rear final torque command value T mr-f1 * On the other hand, when the rear slip flag SFr is "1" and the rear wheels 32 are in a slipping state, the torque command value switching unit 167 outputs the rear slip control torque T mr-slip * is the first rear final torque command value T mr-f1 * Output as

[0109] The correction unit 168 calculates the front torque deviation ΔT f Based on this, the first rear final torque command value T mr-f1 * By correcting the (second) rear final torque command value T mr-f2 * In this embodiment, the correction unit 168 calculates the first rear final torque command value T mr-f1 * Front torque deviation ΔT f By adding mr-f2 * Calculate the following.

[0110] The torque deviation calculation unit 169 calculates the rear torque deviation ΔT r In this embodiment, the torque deviation calculation unit 169 calculates the rear basic torque T mr * to the first rear final torque command value T mr-f1 * By subtracting the rear torque deviation ΔT r Calculate the rear torque deviation ΔT r is input to the correction unit 163 of the front final torque command value calculation unit 151 via the change rate limiting unit 170. That is, the rear torque deviation ΔT rrepresents the amount of torque transferred from the rear motor 31 (rear wheels 32) to the front motor 21 (front wheels 22).

[0111] The change rate limiting unit 170 is configured to limit the rear torque deviation ΔT r is input to the correction unit 163 of the front final torque command value calculation unit 151, the rear torque deviation ΔT r Limits the rate of change of rear torque deviation ΔT r The limit value (upper limit value) for the rate of change of the rear torque deviation ΔT is determined in advance by experiment, simulation, or the like. r This prevents the front wheels 22 from slipping due to a torque shift equivalent to the torque shift.

[0112] [Effect] As described above, in the electric vehicle 10 according to this embodiment, when slippage occurs in the front wheels 22 or the rear wheels 32, rotation speed control is executed to match the rotation speed of the slipping drive wheel, either the front wheels 22 or the rear wheels 32, to the rotation speed of the other drive wheel that is not slipping. Then, the torque (driving force) that should be output by the slipping drive wheel is transferred to the other drive wheel that is not slipping. This eliminates or suppresses slippage. Below, the operation of the control of the electric vehicle 10 according to this embodiment will be described by comparison with a first comparative example and a second comparative example.

[0113] The comparison between the control of the electric vehicle 10 according to this embodiment and the controls of the first and second comparative examples is performed for road surfaces and driving conditions where slippage is likely to occur, as follows: Specifically, it is assumed that the vehicle is traveling on a road surface (such as sand) where resistance increases depending on the amount of slippage, and that at time t0, the vehicle enters an uphill road in a straight line while maintaining the same road surface conditions, while accelerating.

[0114] FIG. 16 shows the longitudinal acceleration A cc10 is a time chart showing the following: In the first comparative example, instead of performing rotation speed control to match the rotation speed of one slipping drive wheel with the rotation speed of the other non-slip drive wheel, the torque (driving force) that should be output from the slipping drive wheel is transferred to the other non-slip drive wheel.

[0115] FIG. 16(A) shows the output torque of the front motor 21 (hereinafter referred to as the front motor torque T mf The solid line in FIG. 16(A) represents the front motor torque T mf The dashed line in Figure 16(A) represents the front basic torque T mf * FIG. 16(B) shows the relationship between the front motor rotation speed ω mf The solid line in FIG. 16(B) is the front motor rotation speed ωmf. The dashed line in FIG. 16(B) is the vehicle speed V. FIG. 16(C) is the output torque of the rear motor 31 (hereinafter referred to as rear motor torque T mr The solid line in FIG. 16(C) represents the rear motor torque T mr The dashed line in Figure 16(C) represents the rear basic torque T mr * FIG. 16(D) shows the rear motor rotation speed ω mr The solid line in FIG. 16(D) represents the rear motor rotation speed ω mr The dashed line in Fig. 16(D) represents the vehicle speed V. Fig. 16(E) shows the longitudinal acceleration A cc The solid line in FIG. 16(E) represents the longitudinal acceleration A cc The dashed line in Figure 16(E) represents the gradient resistance R G is.

[0116] As shown in FIG. 16(B) and FIG. 16(D), when the vehicle enters an uphill road at time t0, the front axle load becomes insufficient until time t1, and the front motor rotation speed ω mf becomes relatively large, and the rear motor rotation speed ω mrbecomes relatively small. That is, from time t0 to time t1, slippage occurs in the front wheels 22. Therefore, as shown in FIGS. 16(A) and 16(C), torque is transferred from the front wheels 22 (front motor 21) to the rear wheels 32 (rear motor 31) after time t1. However, as shown in FIGS. 16(B) and 16(D), the front motor rotation speed ω mf and rear motor rotation speed ω mr The differential rotation ω mfr However, this is not sufficient to prevent the front wheels 22 from slipping. As a result, the resistance of the front wheels 22 increases, and at the same time, the torque of the rear wheels 32 (rear motor torque T mr ) increases to saturation. Therefore, as shown in Figure 16(E), the gradient resistance R G Longitudinal acceleration A is strong enough to overcome cc Therefore, in the control of the first comparative example, when the front wheels 22 slip, the vehicle speed V decreases, and the vehicle decelerates or gets stuck, even though the torque is transferred to the rear wheels 32.

[0117] 17 is a time chart showing longitudinal acceleration and the like when the control of the second comparative example is executed. Similar to the first comparative example, the second comparative example does not perform rotation speed control to match the rotation speed of one slipping drive wheel with the rotation speed of the other non-slip drive wheel, but instead controls the torque (driving force) that should be output from one slipping drive wheel to the other non-slip drive wheel. However, the second comparative example is an example in which the control gain is increased compared to the first comparative example, and adjustments are made to increase the amount of torque transfer when slippage occurs.

[0118] Figure 17(A) shows the front motor torque T mf 17B is a time chart showing the front motor rotation speed ω mf FIG. 17(C) is a time chart showing the rear motor torque T mr FIG. 17(D) is a time chart showing the rear motor rotation speed ω mr FIG. 17(E) is a time chart showing the longitudinal acceleration A cc17 is a time chart showing the above. Each line in Fig. 17 is the same as the example in Fig. 16 relating to the first comparative example.

[0119] As shown in FIG. 17(B) and FIG. 17(D), when the vehicle enters an uphill road at time t0, the front axle load becomes insufficient until time t1, and the front motor rotation speed ω mf becomes relatively large, and the rear motor rotation speed ω mr becomes relatively small. That is, from time t0 to time t1, slippage occurs in the front wheels 22. This occurrence of slippage in the front wheels 22 is the same as in the first comparative example. Then, as shown in FIG. 17(A) and FIG. 17(C), after time t1, torque is transferred from the front wheels 22 (front motor 21) to the rear wheels 32 (rear motor 31), and the differential rotation ω mfr is reduced.

[0120] However, in the control of the second comparative example, the control gain is set to be larger than that of the first comparative example, so as shown in FIGS. 17(A) and 17(C), after time t1 when the torque transfer starts, the front motor torque T mf and rear motor torque T mr As a result, as shown in Fig. 17(B) and Fig. 17(D), the front motor rotation speed ω mf and rear motor rotation speed ω mr also vibrates.

[0121] In the second comparative example in which the control gain is set to a large value, for example, at time t2, the slip of the front wheels 22 is reduced, and the resistance of the front wheels 22 is reduced. Therefore, the torque of the rear wheels 32 (rear motor torque T mr As a result, as shown in FIG. 17(E), in the control of the second comparative example, the gradient resistance R G Longitudinal acceleration A is strong enough to overcome cc Therefore, in the control of the second comparative example, the vehicle speed V increases.

[0122] However, in the control of the second comparative example, the front motor torque T mfand rear motor torque T mr , and the front motor rotation speed ω mf and rear motor rotation speed ω mr The vibration continues after time t1 and does not converge even at time t2, for example. That is, the control of the second comparative example does not resolve the unstable control state in which the front wheels 22 and the rear wheels 32 repeatedly slip and grip.

[0123] 18A and 18B are time charts showing the longitudinal acceleration and the like when the control according to this embodiment is executed. mf 18B is a time chart showing the front motor rotation speed ω mf FIG. 18(C) is a time chart showing the rear motor torque T mr FIG. 18(D) is a time chart showing the rear motor rotation speed ω mr FIG. 18(E) is a time chart showing the longitudinal acceleration A cc 18 is a time chart showing the above. The lines in Fig. 18 are the same as those in Fig. 16 relating to the first comparative example and Fig. 17 relating to the second comparative example.

[0124] As shown in FIG. 18(B) and FIG. 18(D), when the vehicle enters an uphill road at time t0, the front axle load becomes insufficient until time t1, and the front motor rotation speed ω mf becomes relatively large, and the rear motor rotation speed ω mr becomes relatively small. That is, from time t0 to time t1, slippage occurs in the front wheel 22. This occurrence of slippage in the front wheel 22 is the same as in the first and second comparative examples. Then, as shown in FIG. 18(A) and FIG. 18(C), after time t1, torque is transferred from the front wheel 22 (front motor 21) to the rear wheel 32 (rear motor 31), and the differential rotation ω mfr is reduced.

[0125] At this time, in the control according to this embodiment, as shown in FIGS. 18(A) and 18(C), the torque of the slipping front wheel 22 (front motor torque Tmf ) is suppressed, and torque is transferred to the rear wheel 32 that is not slipping. Therefore, from time t1 to time t2, for example, the differential rotation ω mfr As a result, at time t2, the slip of the front wheels 22 is suppressed, so that the resistance of the front wheels 22 is reduced, and at the same time, it is possible to increase the torque of the rear wheels 32. Therefore, as shown in FIG. 18(E), in the control according to this embodiment, the gradient resistance R G Forward and backward acceleration A cc is obtained, and the vehicle speed V can be increased. That is, according to the control according to this embodiment, even when traveling on a road surface where slippage is likely to occur, such as a sandy slope, the electric vehicle 10 does not get stuck and can climb uphill. This is because, unlike the second comparative example and the like, the control according to this embodiment does not increase the rotation speed of the slipping front wheel 22 (front motor rotation speed ω mf ) is calculated by multiplying the rotation speed of the rear wheel 32 (rear motor rotation speed ω mr ) and then torque is transferred from the front wheels 22 to the rear wheels 32.

[0126] As described above, the control method for an electric vehicle according to this embodiment is a control method for an electric vehicle that has first drive wheels (for example, front wheels 22) driven by a first motor (for example, front motor 21) and second drive wheels (for example, rear wheels 32) driven by a second motor (for example, rear motor 31) different from the first motor. In this control method for an electric vehicle, a total torque T corresponding to the driving force required for the electric vehicle is calculated. m1 * is calculated. Then, the total torque T m1 * to the first motor and the second motor, a first basic torque (for example, a front basic torque T mf * ) and a second basic torque (for example, a rear basic torque T mr * ) and are calculated.

[0127] In addition, the rotation speed of the second motor (for example, the rear motor rotation speed ω mr ), a first rotation speed target value (for example, a front rotation speed target value ω mf * Similarly, the rotation speed of the first motor (for example, the front motor rotation speed ω mf ), a second rotation speed target value (for example, a rear rotation speed target value ω mr * ) is calculated based on the first rotation speed target value. Furthermore, a first rotation speed control torque (for example, a front rotation speed control torque T ωf ) is calculated, and a second rotation speed control torque (for example, a rear rotation speed control torque T ωr ) is calculated.

[0128] Then, (a) when the rotation speed of the first motor is greater than the rotation speed of the second motor, a first final torque command value (for example, a (second) front final torque command value T mf-f2 * ) is calculated. Also, a first torque deviation (for example, a front torque deviation ΔT f ) based on the second basic torque (e.g., rear basic torque T mr * ), the final torque command value for the second motor is corrected to obtain a second final torque command value (for example, a (second) rear final torque command value T mr-f2 * ) is calculated.

[0129] Conversely, (b) when the rotation speed of the second motor is greater than the rotation speed of the first motor, a second torque deviation (for example, a rear torque deviation ΔT r ) based on the first basic torque (for example, the front basic torque T mf *) is corrected to obtain the first final torque command value (for example, the (second) front final torque command value T mf-f2 * ) is calculated. Also, the second rotation speed control torque (for example, the rear rotation speed control torque T ωr ), a second final torque command value (for example, rear rotation speed control torque T ωr ) is calculated.

[0130] Then, the first motor and the second motor are driven based on the first final torque command value and the second final torque command value calculated as described above.

[0131] As described above, in the control method for an electric vehicle according to the above embodiment, when one of the drive wheels slips, i.e., when a difference in rotation speed occurs, rotation speed control is performed to control the rotation speed of the slipping drive wheel toward a target value corresponding to the rotation speed of the non-slip drive wheel. After this rotation speed control is performed, the torque to be output by the slipping drive wheel is transferred to the non-slip drive wheel. This control corrects the rotation speed difference when a difference in rotation speed occurs between drive wheels driven by different motors, and facilitates convergence to a stable control state in which rotation speed fluctuations are suppressed. In other words, compared to control that simply transfers the torque of the slipping drive wheel to the non-slip drive wheel in order to maintain the driving force to be exerted by the electric vehicle 10, vibrations in the rotation speed, torque, etc. of the drive wheels can be reduced or suppressed. Furthermore, the rotation speed difference between the drive wheels is likely to be a value corresponding to the road surface, maximizing the driving force transmitted to the road surface and preventing the electric vehicle 10 from getting stuck.

[0132] In the control method for the electric vehicle according to the above embodiment, the rotation speed of the first motor (for example, the front motor rotation speed ω mf ) is the rotation speed of the second motor (for example, the rear motor rotation speed ω mr ), the second final torque command value (for example, the rear final torque command value T mr-f2 * ) is the first torque deviation (for example, the front torque deviation ΔT f ) to the second basic torque (e.g., rear basic torque Tmr * ) is added to the rotation speed of the second motor (for example, the rear motor rotation speed ω mr ) is the rotation speed of the first motor (for example, the front motor rotation speed ω mf ), the first final torque command value (for example, the front final torque command value T mf-f2 * ) is the second torque deviation (for example, rear torque deviation ΔT r ) to the first basic torque (for example, the front basic torque T mf * )

[0133] In this way, by controlling the rotation speed, the output torque that is reduced at the slipping drive wheel is added to the drive wheel that is not slipping and output, so that the driving force of the electric vehicle 10 can be easily and reliably maintained despite control that prioritizes adjustment of the rotation speed.

[0134] In the control method for an electric vehicle according to the above embodiment, the change rate limiting units 165 and 170 limit the first torque deviation (for example, the front torque deviation ΔT f ) and the second torque deviation (for example, rear torque deviation ΔT r ) is set to a predetermined upper limit value. By limiting the first torque deviation and the second torque deviation in this way, slippage of the slipping drive wheel is quickly suppressed, and the transfer of torque makes it difficult for slip to occur in the drive wheels that were not slipping.

[0135] In the control method for the electric vehicle according to the above embodiment, the first rotation speed target value and the second rotation speed target value (front rotation speed target value ω mf * and rear rotation speed target value ω mr * ) is the vehicle speed V and the steering wheel rotation angle (steering rotation angle θ strIn this way, the first rotation speed target value and the second rotation speed target value are determined, and the differential rotation speed ω required in accordance with the turning behavior of the electric vehicle 10 is calculated. mfr As a result, when turning, the front motor torque T mf Interference between the drive wheels is suppressed, and a decrease in yaw rate, etc. is prevented. In other words, even when the electric vehicle 10 is turning, slip control based on the rotation speed is performed, and a driving force appropriate for the turning behavior is obtained.

[0136] In the control method for the electric vehicle according to the above embodiment, the first rotation speed control torque (for example, the front rotation speed control torque T ωf ) is the torque that the first motor should output when the rotation speed of the first motor is equal to the rotation speed of the second motor. ωr ) is the torque that the second motor should output when the rotation speed of the second motor matches the rotation speed of the first motor. By matching the rotation speed of the slipping drive wheel to the rotation speed of the non-slipping drive wheel in this way, it is particularly easy to correct the rotation speed difference and achieve a stable control state where rotation speed fluctuations are suppressed.

[0137] In the control method for the electric vehicle according to the above embodiment, the first rotation speed control torque (for example, the front rotation speed control torque T ωf ) is the first rotation speed deviation (for example, the front rotation speed deviation Δω mf ) based on the torque-to-speed transfer characteristic G of the first motor. pf (s) is calculated by a first model matching filter configured using the second rotation speed control torque (for example, rear rotation speed control torque T ωr ) is the second rotation speed deviation (for example, rear rotation speed deviation Δω mr ) based on the torque-to-speed transfer characteristic G of the second motor. prThe first and second model matching filters are calculated by a second model matching filter configured using the low-pass filter R1(s). These first and second model matching filters include a low-pass filter R1(s). In this way, when each rotation speed control torque is calculated by a model matching filter including the low-pass filter R1(s), problems such as sudden acceleration can be prevented when returning to a road surface where slip is less likely to occur (a so-called high μ road) from a state in which slip has been suppressed by the rotation speed control torque. In addition, slip of the drive wheels can be easily corrected while minimizing discomfort felt by the driver.

[0138] In the control method for the electric vehicle according to the above embodiment, a first disturbance torque (for example, a front disturbance torque T) acting on the first motor is calculated based on the dynamic characteristics of the drive shaft. df ) and the second disturbance torque acting on the second motor (for example, rear disturbance torque T dr ) is estimated. When the rotation speed of the first motor is greater than the rotation speed of the second motor, the first final torque command value (for example, the front final torque command value T mf-f2 * ) is calculated by compensating the first disturbance torque for the first rotation speed control torque. When the rotation speed of the second motor is greater than the rotation speed of the first motor, the second final torque command value (for example, the rear final torque command value T mr-f2 * ) is calculated by compensating the second rotation speed control torque for the second disturbance torque. By compensating for the disturbance torque in this way, the rotation speed of the slipping drive wheel can be made to match the target value corresponding to the rotation speed of the non-slip drive wheel particularly accurately.

[0139] In the control method for the electric vehicle according to the above embodiment, the rotational speed difference ω mfr is calculated, and the difference rotation ω mfr The absolute value of the rotation speed threshold ω m-th When the difference rotation ω mfrDepending on the sign of the differential rotation ω, it is determined that "the rotation speed of the first motor is greater than the rotation speed of the second motor" or "the rotation speed of the second motor is greater than the rotation speed of the first motor." By making such a determination, slip of the drive wheels can be determined particularly accurately. As a result, the differential rotation ω that occurs when the electric vehicle 10 is turning can be determined particularly accurately. mfr This prevents the drive wheels from being erroneously determined to be slipping.

[0140] In the control method for the electric vehicle according to the above embodiment, the first rotation speed control torque (for example, the front rotation speed control torque T ωf ) is the first basic torque (for example, the front basic torque T mf * ) or less. Similarly, the second rotation speed control torque (for example, the rear rotation speed control torque T ωr ) is the second basic torque (for example, the rear basic torque T mr * ) or less. In this way, by preventing the torque generated by the slipping drive wheel from exceeding the base torque, the slip of the drive wheel is controlled to be reduced reliably. In addition, when the slip of the drive wheel stops, the torque target value is smoothly switched.

[0141] In the control method for an electric vehicle according to the above embodiment, when the rotation speed of the first motor is higher than the rotation speed of the second motor, the total torque T m1 * When the rotation speed of the second motor is greater than the rotation speed of the first motor, the total torque T m1 * In this way, when a sudden slip occurs in the drive wheels, the total torque T m1 * By limiting the slippage, both the first drive wheel (for example, the front wheel 22) and the second drive wheel (for example, the rear wheel 32) are prevented from slipping.

[0142] Although the embodiments of the present invention have been described above, the configurations described in the above embodiments merely show some of the application examples of the present invention and are not intended to limit the technical scope of the present invention.

[0143] For example, in the above embodiment and the like, an example has been described in which the present invention is implemented in an electric vehicle 10 that includes front wheels 22 driven by a front motor 21 and rear wheels 32 driven by a rear motor 31 different from the front motor 21, but the present invention is not limited to this. The present embodiment can be suitably applied to any electric vehicle in which multiple drive wheels are driven by multiple different motors. For example, the present invention is also suitable for an electric vehicle in which each of the four wheels is driven by a separate motor. The present invention is also suitable for an electric vehicle equipped with so-called in-wheel motor drive wheels. [Explanation of symbols]

[0144] 10: Electric vehicle, 11: Front drive system, 12: Rear drive system, 13: Battery, 14: Motor controller, 16: Rotation speed control torque limiter, 21: Front motor, 22: Front wheel, 23: Front inverter, 24: Rotation sensor, 25: Current sensor, 26: Front reducer, 27: Drive shaft, 31: Rear motor, 32: Rear wheel, 33: Rear inverter, 34: Rotation sensor, 35: Current sensor, 36: Rear reducer, 37: Drive shaft, 41: Input processing section, 42: Basic Torque calculation unit, 43: slip control calculation unit, 44: vibration suppression control calculation unit, 45: current command value calculation unit, 46: current control calculation unit, 47: total torque calculation unit, 48: torque distribution calculation unit, 51: total torque limit unit, 52: front wheel distribution gain multiplication unit, 53: rear wheel distribution gain multiplication unit, 61: slip determination unit, 62: differential rotation target value calculation unit, 63: front slip control calculation unit, 64: rear slip control calculation unit, 65: torque command value calculation unit, 71: differential rotation calculation unit, 72: slip flag calculation unit, 81: first multiplication unit, 82: Second multiplication unit, 91: Front rotation speed target value calculation unit, 92: Rotation speed control unit, 93: Disturbance torque estimator, 94: Disturbance torque compensation unit, 101: Rotation speed deviation calculation unit, 102: Front model matching compensation unit, 111: First front motor torque estimator, 112: Second front motor torque estimator, 113: Front disturbance torque calculation unit, 121: Rear rotation speed target value calculation unit, 122: Rotation speed control unit, 123: Disturbance torque estimator, 124: Disturbance torque compensation unit, 131: Rotation speed deviation calculation unit, 132: Rear model matching compensation unit, 141: first rear motor torque estimator, 142: second rear motor torque estimator, 143: rear disturbance torque calculator, 151: front final torque command value calculator, 152: rear final torque command value calculator, 161: rotation speed control torque limiter, 162: torque command value switching unit, 163: correction unit, 164: torque deviation calculator, 165: change rate limiter, 166: rotation speed control torque limiter, 167: torque command value switching unit, 168: correction unit, 169: torque deviation calculator, 170: change rate limiter

Claims

1. A control method for an electric vehicle including a first drive wheel driven by a first motor and a second drive wheel driven by a second motor different from the first motor, the method comprising: calculating a total torque corresponding to a driving force required for the electric vehicle; calculating a first basic torque, which is a torque to be output by the first motor, and a second basic torque, which is a torque to be output by the second motor, by distributing the total torque to the first motor and the second motor; calculating a first rotation speed target value, which is a target value for the rotation speed of the first motor, based on the rotation speed of the second motor; calculating a second rotation speed target value, which is a target value for the rotation speed of the second motor, based on the rotation speed of the first motor; calculating a first rotation speed control torque, which is a torque to be output by the first motor, based on the first rotation speed target value; calculating a second rotation speed control torque, which is a torque to be output by the second motor, based on the second rotation speed target value; (a) when the rotation speed of the first motor is greater than the rotation speed of the second motor; calculating a first final torque command value, which is a final torque command value for the first motor, based on the first rotation speed control torque; and calculating a second final torque command value that is a final torque command value for the second motor by correcting the second basic torque based on a first torque deviation that is a deviation between the first basic torque and the first rotation speed control torque; (b) when the rotation speed of the second motor is greater than the rotation speed of the first motor; Calculating the first final torque command value by correcting the first basic torque based on a second torque deviation, which is a deviation between the second basic torque and the second rotation speed control torque; and calculating the second final torque command value based on the second rotation speed control torque; driving the first motor and the second motor based on the first final torque command value and the second final torque command value; A method for controlling an electric vehicle.

2. 2. A control method for an electric vehicle according to claim 1, When the rotation speed of the first motor is greater than the rotation speed of the second motor, the second final torque command value is calculated by adding the first torque deviation to the second basic torque; When the rotation speed of the second motor is higher than the rotation speed of the first motor, the first final torque command value is calculated by adding the second torque deviation to the first basic torque. A method for controlling an electric vehicle.

3. 3. A control method for an electric vehicle according to claim 1 or 2, a predetermined upper limit value is set for the rate of change of the first torque deviation used in the calculation of the second final torque command value and the rate of change of the second torque deviation used in the calculation of the first final torque command value; A method for controlling an electric vehicle.

4. A control method for an electric vehicle according to any one of claims 1 to 3, the first rotation speed target value and the second rotation speed target value are calculated based on a vehicle speed and a rotation angle of a steering wheel; A method for controlling an electric vehicle.

5. A control method for an electric vehicle according to any one of claims 1 to 4, the first rotation speed control torque is a torque that should be output by the first motor when the rotation speed of the first motor is equal to the rotation speed of the second motor; The second rotation speed control torque is a torque that should be output by the second motor when the rotation speed of the second motor is equal to the rotation speed of the first motor. A method for controlling an electric vehicle.

6. A control method for an electric vehicle according to any one of claims 1 to 5, the first rotation speed control torque is calculated by a first model matching filter configured using a transfer characteristic from torque to rotation speed of the first motor, based on a first rotation speed deviation which is a deviation between the rotation speed of the first motor and the first rotation speed target value; the second rotation speed control torque is calculated by a second model matching filter configured using a transfer characteristic from torque to rotation speed of the second motor, based on a second rotation speed deviation which is a deviation between the rotation speed of the second motor and the second rotation speed target value; the first model matching filter and the second model matching filter include low-pass filters; A method for controlling an electric vehicle.

7. A control method for an electric vehicle according to any one of claims 1 to 6, estimating a first disturbance torque acting on the first motor and a second disturbance torque acting on the second motor based on a dynamic characteristic of a drive shaft; when the rotation speed of the first motor is higher than the rotation speed of the second motor, the first final torque command value is calculated by compensating the first rotation speed control torque for the first disturbance torque; When the rotation speed of the second motor is higher than the rotation speed of the first motor, the second final torque command value is calculated by compensating the second rotation speed control torque for the second disturbance torque. A method for controlling an electric vehicle.

8. A control method for an electric vehicle according to any one of claims 1 to 7, calculating a differential rotation, which is a deviation between the rotation speed of the first motor and the rotation speed of the second motor; If the absolute value of the differential rotation is equal to or greater than a threshold value, it is determined that the rotation speed of the first motor is greater than the rotation speed of the second motor, or that the rotation speed of the second motor is greater than the rotation speed of the first motor, depending on the sign of the differential rotation. A method for controlling an electric vehicle.

9. A control method for an electric vehicle according to any one of claims 1 to 8, the first rotation speed control torque is limited to be equal to or less than the first basic torque, The second rotation speed control torque is limited to be equal to or less than the second basic torque. A method for controlling an electric vehicle.

10. A control method for an electric vehicle according to any one of claims 1 to 9, When the rotation speed of the first motor is higher than the rotation speed of the second motor, the total torque is limited in accordance with a differential value of the rotation speed of the second motor; When the rotation speed of the second motor is higher than the rotation speed of the first motor, the total torque is limited in accordance with a differential value of the rotation speed of the first motor. A method for controlling an electric vehicle.

11. A control device for an electric vehicle including a first drive wheel driven by a first motor and a second drive wheel driven by a second motor different from the first motor, a total torque calculation unit that calculates a total torque corresponding to a driving force required for the electric vehicle; a torque distribution calculation unit that calculates a first basic torque, which is a torque to be output by the first motor, and a second basic torque, which is a torque to be output by the second motor, by distributing the total torque to the first motor and the second motor; a first rotation speed target value calculation unit that calculates a first rotation speed target value, which is a target value for the rotation speed of the first motor, based on the rotation speed of the second motor; a second rotation speed target value calculation unit that calculates a second rotation speed target value, which is a target value for the rotation speed of the second motor, based on the rotation speed of the first motor; a first rotation speed control torque calculation unit that calculates a first rotation speed control torque, which is a torque to be output by the first motor, based on the first rotation speed target value; a second rotation speed control torque calculation unit that calculates a second rotation speed control torque, which is a torque to be output by the second motor, based on the second rotation speed target value; (a) a torque command value calculation unit that, when the rotation speed of the first motor is higher than the rotation speed of the second motor, calculates a first final torque command value that is a final torque command value for the first motor based on the first rotation speed control torque, and calculates a second final torque command value that is a final torque command value for the second motor by correcting the second basic torque based on a first torque deviation that is a deviation between the first basic torque and the first rotation speed control torque; (b) when the rotation speed of the second motor is higher than the rotation speed of the first motor, calculates the first final torque command value by correcting the first basic torque based on a second torque deviation that is a deviation between the second basic torque and the second rotation speed control torque, and calculates the second final torque command value based on the second rotation speed control torque; a motor drive control unit that drives the first motor and the second motor based on the first final torque command value and the second final torque command value; A control device for an electric vehicle comprising:

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