Electric vehicle control method and electric vehicle control device

Abstract

A control method for an electric vehicle having an electric motor as a driving source. In the control method, a target value of the torque output to the electric motor, i.e., a torque target value, is set based on vehicle information, and a basic feedback compensation value is calculated based on a parameter representing the rotational state of the electric motor and a vehicle model of the electric vehicle. In addition, the basic feedback compensation value is multiplied by a first gain to calculate a first feedback compensation value. On the other hand, a predetermined specific frequency component is extracted from the basic feedback compensation value, and the specific frequency component is multiplied by a second gain to calculate a second feedback compensation value. Moreover, the torque target value is corrected by using the first feedback compensation value and the second feedback compensation value to calculate a torque command value. Then, the electric motor is driven based on the torque command value.

Description

Technical Field

[0001] The present invention relates to a control method and a control device for an electric vehicle having an electric motor as a driving source. Background Art

[0002] JP2003-009566A discloses vibration reduction control of an electric vehicle using a feedforward compensator and a feedback compensator. The feedforward compensator in the document has a structure that functions as a vibration reduction filter having a characteristic of reducing a frequency component equal to the torsional vibration of a wheel drive system. In addition, the feedback compensator has a structure that performs vibration reduction control based on a deviation between an estimated value and an actual measured value of the motor speed. Summary of the invention

[0003] As described above, the current vibration reduction control is a control to reduce the vibration of the vehicle mainly caused by the torsional vibration of the wheel drive system from the motor to the wheel. On the other hand, in a driving scene with a large driving load such as driving on sandy land, vibration in the up and down directions may occur in the vehicle body. That is, when driving under high load, vibration may occur in the vehicle body due to factors other than the torsional vibration of the wheel drive system, and sufficient vibration reduction effect may not be obtained in the current vibration reduction control.

[0004] An object of the present invention is to provide a control method and a control device for an electric vehicle that can suppress vibrations of the vehicle body caused by factors other than the torsional vibration of the wheel drive system in addition to the vibrations of the vehicle body caused by the torsional vibration of the wheel drive system.

[0005] One embodiment of the present invention is a control method for an electric vehicle having an electric motor as a driving source. In the control method, a target value of the torque output to the electric motor, i.e., a torque target value, is set based on vehicle information, and a basic feedback compensation value is calculated based on a parameter representing the rotation state of the electric motor and a vehicle model of the electric vehicle. In addition, the basic feedback compensation value is multiplied by a first gain to calculate a first feedback compensation value. On the other hand, a predetermined specific frequency component is extracted from the basic feedback compensation value, and the specific frequency component is multiplied by a second gain to calculate a second feedback compensation value. Moreover, the torque target value is corrected by using the first feedback compensation value and the second feedback compensation value to calculate a torque command value. Then, the electric motor is driven based on the torque command value. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] Figure 1 It is a block diagram showing the main structure of an electric vehicle.

[0007] Figure 2 This is a flowchart showing a control method of an electric vehicle.

[0008] Figure 3 This is an example of an accelerator opening-torque table.

[0009] Figure 4 It is an explanatory diagram showing a dynamic model of an electric vehicle.

[0010] Figure 5 This is a block diagram of the external disturbance torque estimation process.

[0011] Figure 6 It is an explanatory diagram of the slope resistance estimation process performed by the slope resistance estimation unit.

[0012] Figure 7 It is a block diagram of the vibration reduction control process.

[0013] Figure 8 is the bandpass filter H 3 (s) characteristic curve diagram.

[0014] Fig. 9 This is a graph showing the frequency of torque pulsation generated when going uphill.

[0015] Fig.10 It means H 4 (s) Graph of filter characteristics.

[0016] Fig.11 Is the gain K (A) fb2 and (B) gain K fb3 Graph showing an example of the settings.

[0017] Fig.12 It is a time chart showing changes in torque, rotation speed, vertical acceleration, and vertical movement amount when the vibration reduction control of the comparative example and the vibration reduction control of the embodiment are performed on sandy land.

[0018] Fig.13 It is a time chart showing the transition of the drive shaft torque and the rotation speed when the vibration reduction control of the comparative example and the vibration reduction control of the embodiment are performed on an uphill road.

[0019] Fig.14 This is a block diagram showing the structure of an electric vehicle according to a first modification.

[0020] Fig.15 This is a block diagram of the vibration reduction control according to the second modification.

[0021] Fig.16 This is a block diagram of the vibration reduction control according to the second modification. DETAILED DESCRIPTION

[0022] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0023] Figure 1 1 is a block diagram showing the main structure of the electric vehicle 100. Figure 1 As shown, the electric vehicle 100 has a battery 1, a motor controller 2, an inverter 3, a motor 4, a reducer 5, a rotation sensor 6, a current sensor 7, a drive shaft 8, and drive wheels 9a and 9b. In addition, an electric vehicle refers to a vehicle that uses an electric motor as a driving source or a braking source. A vehicle that can use an electric motor as a part or all of the driving source or braking source of the vehicle is an electric vehicle. That is, in addition to electric vehicles, electric vehicles also include hybrid vehicles, fuel cell vehicles, etc. The electric vehicle 100 of this embodiment is an electric vehicle that uses an electric motor 4 as a driving source.

[0024] The battery 1 is connected to the motor 4 via the inverter 3, and supplies driving power to the motor 4 by discharging. In addition, the battery 1 can be charged by receiving supply of regenerative power from the motor 4.

[0025] The motor controller 2 is a computer composed of, for example, a central processing unit (CPU), a read-only memory (ROM), a random access memory (RAM), and an input / output interface (I / O interface). The motor controller 2 generates a control signal for directly or indirectly controlling the motor 4 based on vehicle information of the electric vehicle 100. The motor controller 2 is programmed to generate the control signal of the motor 4 at a predetermined control cycle that is predetermined in advance.

[0026] Vehicle information is information indicating the operation state or control state of the entire electric vehicle 100 or each part constituting the electric vehicle 100, i.e., the so-called vehicle variable. Vehicle information can be obtained by detection, measurement, generation, calculation, or estimation. For example, the acceleration in the front-to-back direction of the electric vehicle 100 (hereinafter referred to as the front-to-back acceleration) A L[ m / s -2 ], vehicle speed V [km / h], accelerator opening θ [%], rotor phase α [rad] of motor 4, current i of motor 4 u 、i v 、i w [A], and the DC voltage value V of battery 1 dc [V] (not shown) and the like are vehicle information of the electric vehicle 100. The motor controller 2 controls the electric motor 4 using the vehicle information input as a digital signal, for example.

[0027] The control signal for controlling the motor 4 is, for example, a PWM signal (Pulse Width Modulation signal) for controlling the current of the motor 4. In addition, the motor controller 2 generates a drive signal for the inverter 3 based on the PWM signal. The drive signal for the inverter 3 is also a control signal for controlling the motor 4.

[0028] The inverter 3 has two switching elements (for example, IGBT (Insulated Gate Bipolar Transistor), MOS-FET (metal-oxide-semiconductor field-effect transistor) and other power semiconductor elements) corresponding to each phase. The inverter 3 turns on / off the switching elements according to the drive signal generated by the motor controller 2, thereby converting the DC current supplied from the battery 1 into AC current and adjusting the current supplied to the motor 4. In addition, the inverter 3 reversely converts the AC current generated by the motor 4 through the regenerative braking force into DC current and adjusts the current supplied to the battery 1.

[0029] The motor 4 is, for example, a three-phase AC motor, and generates a driving force using the AC current supplied from the inverter 3. The driving force generated by the motor 4 is transmitted to a pair of left and right drive wheels 9a and 9b via the reducer 5 and the drive shaft 8. In addition, when the motor 4 rotates in conjunction with the drive wheels 9a and 9b, a regenerative braking force is generated, and the kinetic energy of the electric vehicle 100 is recovered as electrical energy.

[0030] The speed reducer 5 is composed of, for example, a plurality of gears and reduces the rotation speed of the motor 4 and transmits the reduced speed to the drive shaft 8, thereby generating a driving torque or a braking torque (hereinafter, simply referred to as torque) proportional to the reduction ratio.

[0031] The rotation sensor 6 detects the rotor phase α of the motor 4 and outputs the detected phase to the motor controller 2. The rotation sensor 6 is, for example, a resolver or an encoder.

[0032] The current sensor 7 detects the current flowing in the motor 4 and outputs the current to the motor controller 2. In the present embodiment, the current sensor 7 detects the three-phase AC current i of the motor 4. u 、i v 、i w In addition, the current sensor 7 may detect the currents of any two phases, and the current of the remaining phase may be obtained through calculation.

[0033] In addition, the longitudinal acceleration A as one of the vehicle information is detected at an arbitrary timing by using an acceleration sensor (not shown) or other controllers. L The accelerator opening θ and the like can be detected by an accelerator opening sensor (not shown) or other controllers. In addition, the vehicle speed V and the DC voltage value V of the battery 1 are dc The same is true for other vehicle information, and the above-mentioned various vehicle information can be detected at any timing using sensors or other controllers not shown.

[0034] Figure 2 1 is a flow chart showing a control method of the electric vehicle 100. Figure 2 As shown, the motor controller 2 sequentially executes input processing, torque target value setting processing, external disturbance torque estimation processing, vibration reduction control processing, current target value calculation processing, and current control processing in each predetermined control cycle.

[0035] The input process of step S201 is a process in which the motor controller 2 receives input of vehicle information and calculates various parameters used in the processes after step S202 as necessary.

[0036] In this embodiment, the motor controller 2 obtains the front and rear acceleration A from various sensors. L , accelerator opening θ, rotor phase α, current i of motor 4 u 、i v 、i w , and the DC voltage value V of battery 1 dc In addition, the motor controller 2 uses part or all of the vehicle information directly obtained to calculate the electrical angular velocity of the motor 4, that is, the motor electrical angular velocity ω e [rad / s], the mechanical angular velocity of the motor 4, i.e., the rotational velocity ω m [rad / s], the rotation speed N of the motor 4 after unit conversion m [rpm], and the angular velocity ω of the drive wheels 9a and 9b w [rad / s], and vehicle speed V, etc. are calculated.

[0037] Specifically, the motor controller 2 calculates the motor electrical angular velocity ω by time differentiation of the rotor phase α. e Then, the motor controller 2 converts the motor electrical angular velocity ω e The rotation speed ω is calculated by dividing by the number of pole pairs of the motor 4. m Furthermore, the motor controller 2 controls the rotation speed ω m Multiply by the unit conversion factor (60 / 2π) to calculate the speed N m .

[0038] In addition, the motor controller 2 sets the rotation speed ω m Or speed N m The angular velocity ω of the driving wheels 9a and 9b is calculated by dividing the transmission ratio of the final gear of the speed reducer 5. w Moreover, the motor controller 2 is responsible for the angular velocity ω w The vehicle speed V is calculated by multiplying the load radius r [m] of the drive wheels 9a and 9b and multiplying the result by the unit conversion coefficient (3600 / 1000).

[0039] In addition, instead of calculating in the above manner, the vehicle speed V may be directly acquired by communicating with other controllers such as a meter and a brake controller. In addition, when wheel speed sensors are respectively provided on a plurality of driving wheels 9a, 9b, the average value of the values ​​of the wheel speed sensors may be used as the vehicle speed V. In addition, for the vehicle speed V, a value acquired from a sensor such as a GPS (Global Positioning System) may be used, a value selected from a wheel speed sensor or the like, or a vehicle speed estimated value calculated using a front and rear acceleration sensor or the like may be used (see Japanese Patent Application Laid-Open No. 2002-127881, etc.).

[0040] The torque target value setting process of step S202 is a process for setting a target value of the drive torque of the electric vehicle 100, that is, a drive torque target value T m The motor controller 2 is, for example, Figure 3 The accelerator opening-torque table shown in FIG. 1 is based on the accelerator opening θ and the rotation speed N m Set the drive torque target value T m That is, the motor controller 2 functions as a drive torque target value setting unit or a torque target value setting unit.

[0041] The external disturbance torque estimation process of step S203 is the following process, that is, the estimated value of the torque (hereinafter referred to as the external disturbance torque) generated by the external disturbance acting on the electric vehicle 100, that is, the external disturbance torque estimation value Td^ is calculated. The external disturbance acting on the electric vehicle 100 refers to an external factor that increases or decreases the driving resistance of the electric vehicle 100. Specifically, the external disturbance acting on the electric vehicle 100 includes the modeling error caused by the change of the vehicle weight corresponding to the air resistance, the number of passengers, and the load, the rolling resistance of the drive wheels 9a, 9b, the slope resistance of the road surface, and the sinking of the drive wheels 9a, 9b relative to the road surface. The motor controller 2 uses the rotation speed ω m The final torque command value T calculated in step S204 mf The external disturbance torque estimated value T is calculated based on the previous value d The external disturbance torque estimation process will be described in detail later.

[0042] The vibration reduction control process of step S204 is a process of adjusting the final torque command value T for suppressing the vibration of the wheel drive system. mf The motor controller 2 uses the drive torque target value T m and the rotation speed ω m The final torque command value T is calculated in a manner that does not sacrifice the torque response of the drive shaft 8. mfTypically, the vibration of the wheel drive system refers to the rotational vibration of the electric vehicle 100 in the front-to-back direction (hereinafter referred to as the front-to-back vibration) caused by the torsional vibration of the drive shaft 8, etc. In addition, the vibration of the wheel drive system also includes the vibration of the electric vehicle 100 in the up-and-down direction (hereinafter referred to as the up-and-down vibration) caused by the sinking of the drive wheels 9a, 9b relative to the road surface, etc. mf The driving control of the electric vehicle 100 can suppress both the front-rear vibration and the up-and-down vibration of the electric vehicle 100. The vibration reduction control process will be described in detail later.

[0043] The current target value calculation process in step S205 is a process of calculating the d-axis current i of the motor 4. d The target value is the d-axis current target value i d *And q-axis current i q The target value is the q-axis current target value i q * (not shown) is calculated. The motor controller 2 holds in advance the final torque command value T mf , rotation speed ω m And the DC voltage value V dc , and the d-axis current target value i d *And q-axis current target value i q * The dq axis current target value table (not shown) associated with the motor controller 2 refers to the dq axis current target value table and generates a corresponding final torque command value T. mf , rotation speed ω m And the DC voltage value V dc The corresponding d-axis current target value i d *And q-axis current target value i q * Perform calculations.

[0044] The current control process of step S206 is a process for controlling the current of the motor 4 to generate a torque for driving or braking the electric vehicle 100. In the current control process, the motor controller 2 first controls the current i of the motor 4 based on the current i of the motor 4. u 、i v 、i w , and the rotor phase α and the d-axis current i d And the q-axis current i q Next, the motor controller 2 calculates the d-axis current target value i d *And q-axis current target value i q *、With d-axis current i d And the q-axis current i q The deviation of the d-axis voltage command value v d And the q-axis voltage command value v qThe motor controller 2 calculates based on the d-axis voltage command value v d And the q-axis voltage command value v q , and the rotor phase α, and the three-phase voltage command value v u 、v v 、v w The motor controller 2 calculates the voltage command value v of the three phases. u 、v v 、v w And the DC voltage value V dc The duty cycle t of the PWM signal input to each phase u ,t v ,t w[ %] for calculation.

[0045] The motor controller 2 controls the motor 4 by opening and closing the switching element of the inverter 3 according to the PWM signal thus obtained. As a result, the motor controller 2 uses the final torque command value T mf The specified desired torque is used to drive or brake the electric vehicle 100. That is, the motor controller 2 and / or the inverter 3 are configured as a motor based on the final torque command value T mf Then, a drive control unit that drives the electric motor 4 functions.

[0046] <External disturbance torque estimation processing>

[0047] The motor controller 2 uses the drive torque target value T in the external disturbance torque estimation process. m To rotation speed ω m The transfer characteristic Gp(s) is a vehicle model of the electric vehicle 100 taking into account the torsional vibration of the wheel drive system. Figure 4 The transfer characteristic Gp(s) is calculated based on the equation of motion derived from the dynamic model of electric vehicle 100 shown in FIG. Figure 4 The symbols in the mechanical model and / or motion equation of the electric vehicle 100 are as follows.

[0048] J m : Inertia of the motor

[0049] J w : Moment of inertia of the driving wheel

[0050] M: The mass of the vehicle

[0051] KD: Torsional rigidity of the wheel drive system

[0052] K t : Coefficient related to the friction between the driving wheel and the road surface

[0053] N: total transmission ratio

[0054] r: load radius of the driving wheel

[0055] ω m : Motor rotation speed

[0056] T m : Driving torque target value

[0057] TD: Torque of the driving wheel

[0058] F: force applied to the vehicle

[0059] V: Vehicle speed (vehicle speed)

[0060] ω w : Angular velocity of the driving wheel

[0061] Can be based on Figure 4 The dynamic model of the electric vehicle 100 shown in the figure derives the following equations of motion (1) to (5). In addition, the symbol "*" in equations (1) to (3) represents time differentiation.

[0062] [Mathematical formula 1]

[0063] J m ·ω m * =T m -TD / N (1)

[0064] 2J w ·ω w * =TD-r·F (2)

[0065] M.V * =F (3)

[0066] TD=KD∫(ω m / N-ω w )dt (4)

[0067] F=K t (r·ω w -V) (5)

[0068] If the transfer characteristic Gp(s) is solved based on the above-mentioned motion equations (1) to (5), it can be expressed by equation (6). In addition, the coefficient a in equation (6) is 1 ~a 4 and coefficient b 0 ~b 3 It is expressed by equations (7) to (14).

[0069] [Mathematical formula 2]

[0070]

[0071] a 4 =2J m ·J w ·M (7)

[0072] a 3 =J m (2J w +M·r 2 )K t (8)

[0073] a 2 =(J m +2J w / N 2 )M·KD (9)

[0074] a 1 =(J m +2J w / N 2 +M·r 2 / N 2 )KD·K t (10)

[0075] b 3 =2J w ·M (11)

[0076] b 2 =(2J w +M·r 2 )K t (12)

[0077] b 1 =M.KD (13)

[0078] b 0 =KD·K t (14)

[0079] If we examine the extreme value and zero value of the transfer characteristic Gp(s) shown in the above equation (6), one extreme value and one zero value are extremely close values. This means that α and β in the following equation (15) are extremely close values.

[0080] [Mathematical formula 3]

[0081]

[0082] Therefore, by performing pole-zero cancellation approximating α=β in equation (15), it is possible to obtain a transfer characteristic Gp(s) in the form of (2nd order) / (3rd order) as shown in the following equation (16).

[0083] [Formula 4]

[0084]

[0085] In addition, the coefficient a used in the denominator of equation (16) can be used 1 ′ and coefficient a 3 The natural vibration angular velocity ω is expressed by the following equation (17): p . And, the natural vibration angular velocity ω p It can be converted into the resonance frequency (natural vibration frequency) f by the following formula (18): p .

[0086] [Formula 5]

[0087] ω p =(a 1 ′ / a 3 ′) 1 / 2 (17)

[0088] f p =ω p / 2π (18)

[0089] In the present embodiment, the motor controller 2 uses the transfer characteristic Gp(s) of equation (16) in the external disturbance torque estimation process, but the transfer characteristic Gp(s) represented by the following equation (19) may be used instead of the transfer characteristic Gp(s) of equation (16). The equivalent mass M used in the transfer characteristic Gp(s) of equation (19) is: v As shown in formula (20), based on the mass M of the vehicle and the inertia moment J of the motor 4, m , and the moment of inertia J of the drive wheels 9a, 9b w In addition, the coefficient K used in the transfer characteristic Gp(s) of equation (19) is M It is expressed by formula (21).

[0090] [Mathematical formula 6]

[0091]

[0092]

[0093]

[0094] Figure 5 This is a block diagram of the external disturbance torque estimation process. Figure 5 As shown, the motor controller 2 functions as a first motor torque estimating unit 501 , a second motor torque estimating unit 502 , a subtracting unit 503 , a slope resistance estimating unit 504 , and a subtracting unit 505 in order to execute the external disturbance torque estimation process.

[0095] The first motor torque estimation unit 501 calculates a first motor torque estimation value T1^. The first motor torque estimation value T1^ is based on the rotation speed ω m In this embodiment, the first motor torque estimating unit 501 calculates the rotation speed ω m More specifically, the first motor torque estimation unit 501 is composed of a low-pass filter H 1 (s) and the inverse characteristic 1 / Gp(s) of the transfer characteristic Gp(s) and the filter having the characteristic represented by H1(s) / Gp(s). 1 (s) Using the time constant τ v It is represented by the following formula (22).

[0096] [Mathematical formula 7]

[0097]

[0098] The second motor torque estimation unit 502 calculates a second motor torque estimation value T2 ^. The second motor torque estimation value T2 ^ is based on the final torque command value T mf In the present embodiment, the first motor torque estimating unit 501 estimates the final torque command value T mf More specifically, the second motor torque estimation unit 502 uses a low-pass filter H 1 (s) composition.

[0099] The subtracting unit 503 calculates a deviation (hereinafter referred to as torque estimation deviation ΔT ^) between the first motor torque estimation value T1 ^ and the second motor torque estimation value T2 ^. In the present embodiment, the subtracting unit 503 calculates the torque estimation deviation ΔT ^ by subtracting the first motor torque estimation value T1 ^ from the second motor torque estimation value T2 ^.

[0100] The slope resistance estimation unit 504 is based on the longitudinal acceleration A L The estimated slope resistance value T g The slope resistance is the driving resistance caused by the slope of the road surface. The slope resistance estimated value T g In this embodiment, the slope resistance estimation unit 504 calculates the longitudinal acceleration A L Multiply by the coefficient K g The slope resistance estimated value T is calculated g ^.

[0101] Figure 61 is an explanatory diagram of the slope resistance estimation process performed by the slope resistance estimation unit 504. The force F applied to the electric vehicle 100, the gravity Mg acting on the electric vehicle 100, and the slope ψ of the road surface are Figure 6 Therefore, for the slope ψ, the coefficient K g It is expressed by the following equation (23). L Multiply by the coefficient K g The slope resistance estimated value T for the electric vehicle 100 to achieve equilibrium on the road surface with a slope of ψ is calculated. g ^.

[0102] [Mathematical formula 8]

[0103]

[0104] The subtraction unit 505 subtracts the estimated slope resistance value T from the estimated torque deviation ΔT ^. g ^ and calculate the external disturbance torque estimated value T d ^.

[0105] As described above, the external disturbance torque estimated value T d The slope resistance estimated value T is subtracted from the torque estimated deviation ΔT^ which comprehensively includes all external disturbance torques caused by external disturbances. g Therefore, the external disturbance torque estimated value T d ^The influence of slope resistance is weakened or eliminated.

[0106] Among the plurality of external disturbance factors, the slope resistance and the sinking of the driving wheels 9a and 9b relative to the road surface are factors that cause the running resistance to vary particularly greatly. As described above, the external disturbance torque estimated value T d Therefore, when the driving wheels 9a and 9b are traveling on a road surface such as a sandy road surface, a deep snow road surface, or a muddy road surface (hereinafter referred to as a soft road surface) where the driving wheels 9a and 9b are sunken relative to the road surface, the external disturbance torque estimated value T d On the other hand, when the driving wheels 9a and 9b are traveling on a normal road surface (hereinafter referred to as a hard road surface) that hardly sinks relative to the road surface, the external disturbance torque estimated value T d That is, the external disturbance torque estimated value T d ^ indicates the change in the running resistance of the road surface.

[0107] <Vibration reduction control processing>

[0108] Figure 7 is a block diagram of the vibration reduction control process. Figure 7As shown, the motor controller 2 functions as a feedforward compensator 701 , a feedback compensator 702 , and a final torque command value calculation unit 703 for the vibration reduction control process.

[0109] The feedforward compensator 701 is based on the drive torque target value T m For the first torque target value T m1 In this embodiment, the feedforward compensator 701 is a vibration reduction filter, which calculates the drive torque target value T m The first torque target value T is calculated by filtering. m1 The feedforward compensator 701 is composed of, for example, an ideal transfer characteristic Gm(s) and an inverse characteristic 1 / Gp(s) of the transfer characteristic Gp(s), and has a transfer characteristic of Gm(s) / Gp(s). The feedforward compensator 701 functions as a vibration reduction filter for suppressing torsional vibration of the wheel drive system. In addition, the ideal transfer characteristic Gm(s) is obtained from the drive torque target value T m To rotation speed ω m The ideal transfer characteristic is a transfer characteristic in which the attenuation coefficient (not shown) of the actual transfer characteristic Gp(s) is set to "1".

[0110] The feedback compensator 702 is based on the rotation speed ω m The second torque target value T m2 Perform calculations.

[0111] The final torque command value calculation unit 703 calculates the first torque target value T output by the feedforward compensator 701. m1 The second torque target value T output by the feedback compensator 702 is fed back m2 , thus the final torque command value T mf That is, the final torque command value calculation unit 703 uses the second torque target value T m2 The first torque target value T m1 Correction is performed to the final torque command value T mf In the present embodiment, the final torque command value calculation unit 703 is, for example, a subtraction unit, which calculates the final torque command value from the first torque target value T m1 Subtract the second torque target value T m2 The final torque command value T is calculated mf In addition, the second torque target value T m2 With respect to the first torque target value T m1 The feedback of the second torque target value T m2 Relative to the driving torque target value T m Therefore, the final torque command value calculation unit 703 can calculate the drive torque target value T m Feedback second torque target value T m2 .

[0112] According to the final torque command value T mf The motor 4 is driven. mf When the motor 4 is driven, external disturbance d sometimes acts. Figure 7 , the electric vehicle 100 is represented by the transfer characteristic Gp′(s).

[0113] The feedback compensator 702 is constructed as follows.

[0114] That is, the feedback compensator 702 includes an external disturbance estimation filter 710 , a first feedback compensation value calculation unit 711 , a second feedback compensation value calculation unit 712 , a third feedback compensation value calculation unit 713 , a frequency setting unit 714 , a second torque target value calculation unit 715 , and a gain setting unit 716 .

[0115] The disturbance estimation filter 710 is composed of a rotation speed estimator 721 , a subtractor 722 , and a disturbance estimator 723 .

[0116] The rotation speed estimator 721 is based on the final torque command value T mf For the rotation speed ω m The estimated value of the rotation speed ω m More specifically, the rotation speed estimator 721 is a filter of the transfer characteristic Gp(s) of the vehicle model of the electric vehicle 100. That is, the rotation speed estimator 721 uses the transfer characteristic Gp(s) to calculate the final torque command value T mf Calculate the estimated rotation speed value ω by filtering m ^.

[0117] The subtractor 722 calculates the rotation speed ω m The actual measured value and the estimated rotation speed ω m Deviation of ^Δω m In this embodiment, the subtractor 722 calculates the rotation speed estimated value ω from m ^ minus the actual measured value of the rotation speed ω- m And calculate the deviation Δω m .

[0118] The external disturbance estimator 723 is based on the deviation Δω m The estimated disturbance d^, which is an estimated value of the disturbance d acting on the electric vehicle 100, is calculated. The disturbance estimator 723 is, for example, a filter composed of a bandpass filter H 2 (s), and the reverse characteristic 1 / Gp(s) of the transfer characteristic Gp(s), which is composed of H 2(s) / Gp(s) represents the characteristics. Bandpass filter H 2 (s) is set to pass the frequency band of the torsional vibration of the wheel drive system and the frequency component of the natural vibration of the electric vehicle 100 caused by the external disturbance d. 2 (s) is set so that the difference between the denominator and the numerator is greater than or equal to the difference between the denominator and the numerator of the transfer characteristic Gp(s). The external disturbance estimator 723 uses a bandpass filter H having the above characteristics. 2 (s), so that the feedback compensator 702 functions as a feedback element for suppressing the torsional vibration of the wheel drive system and the vibration caused by the external disturbance d. Therefore, the estimated external disturbance d^ calculated by the external disturbance estimator 723 is a feedback compensation value (hereinafter sometimes referred to as a basic feedback compensation value) used as a basis in the feedback compensator 702. Therefore, the external disturbance estimator 723 functions as a basic feedback compensation value calculation unit.

[0119] In addition, for example, in the bandpass filter H 2 (s) When the bandpass filter H is composed of a first-order high-pass filter and a first-order low-pass filter, 2 (s) can be expressed by the following equation (24). In addition, the time constant τ of the high-pass filter used in equation (24) is H and cutoff frequency f HC , and the time constant τ of the low-pass filter L and cutoff frequency f LC is the resonant frequency f of the torsional vibration of the wheel drive system p and a predetermined coefficient k and is expressed by the following equations (25) to (28).

[0120] [Mathematical formula 9]

[0121]

[0122]

[0123] f HC = k·f p (26)

[0124]

[0125]

[0126] The first feedback compensation value calculation unit 711 calculates the feedback compensation value C1 based on the estimated external disturbance d^ as the basic feedback compensation value. The feedback compensation value C1 is a feedback compensation value for compensating for the torsional vibration of the wheel drive system. In this embodiment, the first feedback compensation value calculation unit 711 uses the multiplication unit 731 to multiply the estimated external disturbance d^ by the gain K fb1 And calculate the feedback compensation value C1. Gain K fb1 It is appropriately predetermined based on experiments, simulations, or the like.

[0127] The second feedback compensation value calculation unit 712 calculates the feedback compensation value C2 based on the estimated external disturbance d^ as the basic feedback compensation value. The feedback compensation value C2 is a feedback compensation value for compensating for vertical vibrations caused by tire sinking when the vehicle is traveling on a soft road surface such as sand.

[0128] In the present embodiment, the second feedback compensation value calculation unit 712 is composed of a specific frequency component extractor 732 and a multiplication unit 733 .

[0129] The specific frequency component extractor 732 is a filter that extracts the frequency component of the up and down vibration generated on a soft road surface such as sandy land from the estimated external disturbance d^. The specific frequency here is a specific frequency or a specific frequency band extracted by the specific frequency component extractor 732. In addition, the specific frequency component is a component of a specific frequency extracted by the specific frequency component extractor 732 from the estimated external disturbance d^. The specific frequency component extractor 732 is, for example, a bandpass filter H 3 (s) composition. In addition, the frequency component of the up and down vibration generated on a soft road surface such as sand is the natural vibration frequency component of the electric vehicle 100, which is known through experiments or simulations. Therefore, the bandpass filter H 3 (s) is set so as to allow at least the frequency component of the up-and-down vibration generated on a soft road surface to pass.

[0130] Figure 8 is the bandpass filter H 3 (s) characteristic curve diagram. Figure 8 For example, the frequency of the up-and-down vibration generated when the electric vehicle 100 is traveling on sandy land (hereinafter referred to as the sandy land up-and-down vibration frequency) f sand For example, it is determined based on the suspension characteristics of the tires and the vehicle body of the electric vehicle 100 and the sinking characteristics of the tires relative to sand. sand It is known through experiments or simulations. Therefore, the bandpass filter H 3 (s) is set, for example, as shown in the following equation (29) so that the vertical vibration frequency f of the sandy soil is sand The component passes through. In addition, the time constant τ sandIt is represented by the following formula (30).

[0131] [Formula 10]

[0132]

[0133]

[0134] exist Figure 8 In the bandpass filter H 3 (s) is set to make the sand vibrate up and down at a frequency f sand However, this is not limited to the bandpass filter H. 3 (s) can be set to make the sand vibrate up and down at a frequency f sand and its surrounding frequencies pass. That is, Figure 8 In the bandpass filter H 3 (s) The gain can be set to, for example, the frequency f of the vibration of the sandy ground. sand A plot of a trapezoid with respect to the center frequency.

[0135] Bandpass filter H for the case of considering the up-and-down vibrations generated on soft roads other than sandy land 3 The setting of (s) is also the same as that in the case of considering the up and down vibrations generated on the sandy land. 3 (s) can be set so that the frequencies of the up and down vibrations generated on each soft road surface can pass through. 3 (s) can be set so that a series of frequency bands including the frequencies of up and down vibrations generated on various soft road surfaces can pass through.

[0136] Multiplication unit 733 (see Figure 7 ) The specific frequency component extracted by the specific frequency component extractor 732 is multiplied by a prescribed gain K fb2 Thus, the feedback compensation value C2 is calculated. Gain K fb2 is variable, gain K fb2 The value of is adjusted by the gain setting unit 716.

[0137] The third feedback compensation value calculation unit 713 calculates a feedback compensation value C3 based on the estimated external disturbance d^ as a basic feedback compensation value. The feedback compensation value C3 is a feedback compensation value for compensating for vibrations generated in the electric vehicle 100 due to torque ripple (cogging vibration) when going uphill.

[0138] In the present embodiment, the third feedback compensation value calculation unit 713 is composed of a specific frequency component extractor 734 and a multiplication unit 735 .

[0139] The specific frequency component extractor 734 is a filter that extracts the frequency component of the natural vibration of the electric vehicle 100 generated in a driving scene requiring high torque such as an uphill road from the estimated external disturbance d^. The specific frequency here refers to a specific frequency or a specific frequency band extracted by the specific frequency component extractor 734. In addition, the specific frequency component is a component of a specific frequency extracted by the specific frequency component extractor 734 from the estimated external disturbance d^. The specific frequency component extractor 734 is, for example, a bandpass filter H 4 (s) composition. Bandpass filter H 4 (s) is set in the following manner.

[0140] first, Fig. 9 is the frequency of the torque pulsation generated when going uphill (hereinafter referred to as the torque pulsation frequency) F tr The curve diagram of Fig. 9 As shown, the torque pulsation frequency F tr With the rotation speed ω m In addition, the torque pulsation frequency F tr The torque pulsation of the electrical angle X is represented by a solid line, and the torque pulsation of the electrical angle Y (X < Y) is represented by a dashed line. m For a certain speed ω 1 In the case of X times, the frequency of the torque pulsation is "f x ", the torque pulsation frequency of Y times is "f y ”.

[0141] Fig.10 is the bandpass filter H 4 (s) characteristic curve diagram. Fig.10 The horizontal axis is logarithmic. For example, the torque pulsation frequency f of each order generated when the electric vehicle 100 goes uphill x 、f y It is known through experiments or simulations. Therefore, the bandpass filter H 4 (s) is set, for example, as shown in the following equation (31) so that the torque pulsation frequency f x , and Y times the torque pulsation frequency f y In addition, the time constant τ involved in the X-order torque pulsation X The time constant τ associated with the Y-order torque pulsation is expressed by the following equation (32): Y It is represented by the following formula (33).

[0142] [Mathematical formula 11]

[0143]

[0144]

[0145]

[0146] And, as mentioned above, the torque pulsation frequency f x 、f y According to the rotation speed ω m and changes, thus determining the bandpass filter H 4 (s) characteristic torque pulsation frequency f x 、f y That is, the bandpass filter H 4 (s) according to the characteristics of the rotation speed ω m The frequency setting unit 714 performs a band pass filter H 4 (s) adjustment.

[0147] The frequency setting unit 714 is based on the rotation speed ω m The bandpass filter H 4 (s) Torque pulsation frequency f x 、f y Specifically, the frequency setting unit 714 changes the rotation speed ω m The larger the torque pulsation frequency f x 、f y The larger the torque pulsation frequency f x 、f y Thus, the time constant τ X , τ Y The result of the adjustment is based on the rotation speed ω m So the bandpass filter H 4 (s) characteristic changes.

[0148] In addition, Fig.10 In the bandpass filter H 4 (s) is set so that the torque pulsation frequency components of each order can pass through roughly accurately. However, this is not limited to this. The bandpass filter H 4 (s) can also be set so that the torque pulsation frequency of each order and the frequency near it pass through. Fig.10 In the bandpass filter H 4 (s) can be set to, for example, a torque pulsation frequency f x times x The trapezoidal curve diagram of the center frequency and the torque pulsation frequency f y A combination of a trapezoidal graph with center frequency.

[0149] Here, the bandpass filter H is schematically shown when considering the X-order torque ripple and the Y-order torque ripple. 4(s), but the bandpass filter H 4 (s) can also be set to a structure that only considers the torque pulsation of X or Y order. 4 (s) A configuration may be adopted in which only torque pulsations of an order other than X and / or Y may be considered.

[0150] Multiplication unit 735 (see Figure 7 ) The specific frequency component extracted by the specific frequency component extractor 734 is multiplied by a prescribed gain K fb3 Thus, the feedback compensation value C3 is calculated. Gain K fb3 Variable, gain K fb3 The value of is adjusted by the gain setting unit 716.

[0151] The second torque target value calculation unit 715 calculates the second torque target value T based on the feedback compensation values ​​C1, C2, and C3. m2 In the present embodiment, the second torque target value calculation unit 715 is composed of, for example, adder units 715a and 715b. The adder unit 715a adds the feedback compensation value C2 output by the second feedback compensation value calculation unit 712 and the feedback compensation value C3 output by the third feedback compensation value calculation unit 713. The adder unit 715b further adds the feedback compensation value C1 output by the first feedback compensation value calculation unit 711 to the output of the adder unit 715a to calculate the second torque target value T. m2 That is, the second torque target value calculation unit 715 calculates the second torque target value T by summing up the feedback compensation values ​​C1, C2, and C3. m2 .

[0152] The gain setting unit 716 adjusts the gain K of the second feedback compensation value calculation unit 712 according to the travel load. fb2 , and the gain K of the third feedback compensation value calculation unit 713 fb3 That is, when driving on a soft road surface such as sandy land or an uphill road, or when driving with a high driving resistance, or when driving with a high torque is required, the gain setting unit 716 adjusts the gain K according to the driving resistance. fb2 , K fb3 In the present embodiment, the gain setting unit 716 is based on the external disturbance torque estimation value T d ^ and adjust the gain K fb2 , K fb3 .

[0153] Fig.11 Is the gain K (A) fb2 and (B) gain K fb3 Graph showing an example of the settings.

[0154] like Fig.11 As shown in (A), the gain K of the second feedback compensation value calculation unit 712 is fb2 The external disturbance torque estimated value T d When the absolute value of ^ is greater than or equal to a predetermined threshold value Th1 and the external disturbance torque estimated value T d That is, the gain setting unit 716 increases based on the external disturbance torque estimated value T d ^ and determines whether the vehicle is traveling on a soft road surface with large driving resistance. d When the driving resistance is small and the vehicle is not traveling on a soft road such as sand, the gain setting unit 716 sets the gain K of the second feedback compensation value calculation unit 712 to fb2 As a result, when the vehicle is traveling on a hard road, the second feedback compensation value calculation unit 712 becomes substantially ineffective, thereby preventing overcompensation based on the feedback compensation value C2.

[0155] On the other hand, when it is determined that the external disturbance torque estimated value T d When the driving resistance is greater than or equal to the threshold value Th1 and the vehicle is traveling on a soft road such as sandy land, the gain setting unit 716 sets the gain K fb2 Adjust to, for example, the external disturbance torque estimated value T d That is, the greater the torque output by the motor 4, the greater the gain K fb2 Thus, an appropriate feedback compensation value C2 is calculated according to the sinking amount of the drive wheels 9a, 9b on the soft road surface (the softness of the soft road surface).

[0156] like Fig.11 As shown in (B), the gain K of the third feedback compensation value calculation unit 713 is fb3 Set to the external disturbance torque estimated value T d When the absolute value of ^ is greater than or equal to a predetermined threshold value Th2, the external disturbance torque estimated value T d That is, the gain setting unit 716 increases based on the external disturbance torque estimated value T d ^ and judge whether it is traveling on an uphill road with large driving resistance and high torque requirement. d When the driving resistance is small and the vehicle is not traveling on an uphill road, the gain setting unit 716 sets the gain K of the third feedback compensation value calculation unit 713 to fb3 As a result, when traveling on a flat road or a downhill road, the third feedback compensation value calculation unit 713 becomes substantially ineffective, thereby preventing overcompensation based on the feedback compensation value C3.

[0157] On the other hand, when it is determined that the external disturbance torque estimated value Td When the driving resistance is large and the driving scene requires high torque, the gain setting unit 716 sets the gain K fb3 Adjust to, for example, the external disturbance torque estimated value T d That is, the greater the torque output by the motor 4, the greater the gain K fb3 Thus, an appropriate feedback compensation value C3 is calculated according to the magnitude of the torque ripple.

[0158] In principle, threshold value Th2 for determining a soft road surface is a different value from threshold value Th1 for determining an uphill road. However, threshold value Th2 may be the same value as threshold value Th1 depending on actual vibration characteristics of electric vehicle 100 and the like.

[0159] In the present embodiment, as described above, the gain setting unit 716 is based on the final torque command value T mf and the rotation speed ω m The estimated external disturbance torque value T d ^ and judge soft road and / or uphill road, and adjust the gain K fb2 , K fb3 However, the present invention is not limited to this. For example, the gain setting unit 716 may replace the external disturbance torque estimation value T d ^Based on the driving torque target value T m Or the final torque command value T mf And make the same judgments and adjustments.

[0160] However, based on the drive torque target value T m Or the final torque command value T mf When the above judgment and adjustment are performed, compared with the case where the above judgment and adjustment are performed based on the external disturbance torque estimated value Td^, the judgment and adjustment can be performed more simply. d The determination of ^ is almost directly based on the running resistance, whereas the determination based on the drive torque target value T m Or the final torque command value T mf The judgment is at least a judgment of a driving scene that requires high torque.

[0161] In addition, if the gain K is set to fb2 and / or gain K fb3 If the value of is set to a large value, high-frequency noise may be generated. Therefore, when the running resistance is large or high torque is required as described above, the gain K is set to fb2 and / or gain K fb3By setting it to a larger value, the stability of the control is ensured, and the vibration reduction control is particularly suitable for each driving scene.

[0162] As described above, electric vehicle 100 of the present embodiment includes three feedback compensation value calculation units, namely, first feedback compensation value calculation unit 711 , second feedback compensation value calculation unit 712 , and third feedback compensation value calculation unit 713 , in feedback compensator 702 , which is one of the elements for implementing vibration reduction control processing.

[0163] The first feedback compensation value calculation unit 711 is the most basic main feedback element for suppressing vibrations that can be generated regardless of the driving resistance, such as torsional vibrations of the wheel drive system. In contrast, the second feedback compensation value calculation unit 712 and the third feedback compensation value calculation unit 713 are auxiliary feedback elements for suppressing additional vibrations generated in specific driving scenarios with large driving resistance, such as soft roads such as sandy land or uphill roads.

[0164] Therefore, the feedback compensation value C1 output by the first feedback compensation value calculation unit 711 can be called the main feedback compensation value or the first feedback compensation value in relation to the feedback compensation values ​​C2 and C3. fb1 With gain K fb2 And the gain K fb3 In the relationship between , it can be called the main feedback gain, the first feedback gain, or the first gain.

[0165] Furthermore, the feedback compensation value C2 output by the second feedback compensation value calculation unit 712 and / or the feedback compensation value C3 output by the third feedback compensation value calculation unit 713 may be referred to as a sub-feedback compensation value or a second feedback compensation value in relation to the feedback compensation value C1. fb2 and the gain K used by the third feedback compensation value calculation unit 13 fb3 With gain K fb1 In the relationship between , it can be called sub-feedback gain, second feedback gain or second gain.

[0166] <Function>

[0167] Next, the operation related to the vibration reduction control of the electric vehicle 100 configured as described above will be described.

[0168] Fig.12 The torque T and the rotation speed N are shown when the vibration reduction control of the comparative example and the vibration reduction control of the present embodiment are performed on sandy land. m , vertical acceleration G UD And the up and down movement δ UDThe comparative vibration reduction control mentioned here is a vibration reduction control in which the feedback compensator 702 has only the first feedback compensation value calculation unit 711 and does not have the second feedback compensation value calculation unit 712 and the third feedback compensation value calculation unit 713.

[0169] Fig.12 (A) to (D) show the torque T and the speed N when the proportional vibration reduction control is performed on sandy land. m , vertical acceleration G UD And the up and down movement δ UD Timing diagram of the transition. Fig.12 (E) to (H) show the torque T and the rotation speed N when the vibration reduction control of this embodiment is performed on sandy land. m , vertical acceleration G UD And the up and down movement δ UD In addition, due to the influence of the tire sinking in the sand, the running resistance in the forward direction increases, and as a result, the external disturbance torque estimated value T d ^ is always positive.

[0170] like Fig.12 As shown in (A), from the time t0 when the electric vehicle 100 is stopped, the driver steps on the accelerator and inputs the drive torque target value T according to the ramp function. m In the proportional vibration reduction control, the feedback compensator 702 only has the first feedback compensation value calculation unit 711, and does not have the second feedback compensation value calculation unit 712. Therefore, in the proportional vibration reduction control, Fig.12 As shown in (B) to (D), at time t1 to t4 after time t0, the speed N m , vertical acceleration G UD And the up and down movement δ UD Vibration is generated periodically and continuously. This indicates that the driving wheels 9a and 9b are vibrating up and down due to sinking on the sandy road surface. That is, in the proportional vibration reduction control, the second torque target value T m2 By feeding back only the feedback compensation value C1, the torsional vibration of the wheel drive system is suppressed, but the driving wheels 9a and 9b sink into the sandy road surface, causing up and down vibrations.

[0171] On the other hand, Fig.12 As shown in FIG. 5E, in the electric vehicle 100 implementing the vibration reduction control of this embodiment, the driver steps on the accelerator from the time t0 when the electric vehicle 100 is stopped, and the drive torque target value T is input according to the ramp function. mHowever, in the vibration reduction control of the present embodiment, the feedback compensator 702 has a second feedback compensation value calculation unit 712 in addition to the first feedback compensation value calculation unit 711. Therefore, in the vibration reduction control of the present embodiment, Fig.12 As shown in (F) to (H), at time t1 to t4 after time t0, the rotation speed N is lower than that of the case where the vibration reduction control of the comparative example is performed. m , vertical acceleration G UD And the up and down movement δ UD That is, as the second torque target value T m2 , the total value of the feedback compensation value C1 and the feedback compensation value C2 is fed back. As a result, in the vibration reduction control of this embodiment, not only the torsional vibration of the wheel drive system but also the up and down vibration of the drive wheels 9a and 9b caused by sinking on the sandy road surface is suppressed.

[0172] In particular, in the vibration reduction control of the present embodiment, the external disturbance torque estimated value T d The gain K of the second feedback compensation value calculation unit 712 is adjusted. fb2 , thereby suppressing the up and down vibration during the period from time t0 to the very early time t1 to around time t2.

[0173] Fig.13 The driving shaft torque T is shown when the vibration reduction control of the comparative example and the vibration reduction control of the present embodiment are performed on an uphill road. D / S And the speed N m The comparative vibration reduction control mentioned here is a vibration reduction control in which the feedback compensator 702 has only the first feedback compensation value calculation unit 711 and does not have the second feedback compensation value calculation unit 712 and the third feedback compensation value calculation unit 713.

[0174] Fig.13 (A) and (B) show the drive shaft torque T when proportional vibration reduction control is performed on an uphill road. D / S And the speed N m In addition, Fig.13 (C) and (D) show the drive shaft torque T when the vibration reduction control of this embodiment is performed on an uphill road. D / S And the speed N m In addition, on an uphill road, the running resistance in the forward direction is large, and as a result, the external disturbance torque estimated value T d ^ is always a positive value. In addition, here, from the state where the electric vehicle 100 stops at time t0, the driver steps on the accelerator and inputs the drive torque target value T according to the ramp function. m .

[0175] In the vibration reduction control of the comparative ratio, the feedback compensator 702 does not include the third feedback compensation value calculation unit 713 for suppressing the vibration associated with the torque pulsation generated on the uphill road. Therefore, not only the torsional vibration of the wheel drive system but also the torque pulsation due to the cogging vibration is generated. Fig.13 As shown in (A) and (B), the drive shaft torque T D / S And the speed N m As a result, the vehicle body vibrates due to the torque pulsation. That is, in the vibration reduction control of the comparison ratio, the second torque target value T m2 Only the feedback compensation value C1 is fed back, and as a result, the torsional vibration of the wheel drive system is suppressed, but vibration occurs due to torque ripple.

[0176] On the other hand, the electric vehicle 100 that implements the vibration reduction control of the present embodiment includes the third feedback compensation value calculation unit 713 in addition to the first feedback compensation value calculation unit 711 in the feedback compensator 702. Therefore, in the vibration reduction control of the present embodiment, Fig.13 As shown in (C) and (D), the drive shaft torque T D / S And the speed N m That is, as the second torque target value T m2 The total value of the feedback compensation value C1 and the feedback compensation value C3 is fed back, and as a result, in the vibration reduction control of the present embodiment, not only the torsional vibration of the wheel drive system but also the vibration associated with the torque pulsation is suppressed. Therefore, according to the vibration reduction control of the present embodiment, the electric vehicle 100 can start and accelerate smoothly on an uphill road.

[0177] In particular, in the vibration reduction control of the present embodiment, the external disturbance torque estimated value T d The gain K of the third feedback compensation value calculation unit 713 is adjusted. fb3 In the vibration reduction control of the present embodiment, according to the rotation speed ω m The bandpass filter H constituting the third feedback compensation value calculation unit 713 is appropriately adjusted. 4 Therefore, in the vibration reduction control of the present embodiment, the vibration associated with the torque ripple is reliably suppressed during the period from the time t0 to the very early time t1 or so.

[0178] <First Modification>

[0179] In the above embodiment, the electric vehicle 100 of two-wheel drive (2WD) is described in which a pair of left and right driving wheels 9a and 9b are driven by one motor 4, but the present invention is also applicable to an electric vehicle 1200 of four-wheel drive (4WD).

[0180] Fig.14 1 is a block diagram showing the structure of an electric vehicle 1200 according to the first modification. Fig.14 As shown, a 4WD electric vehicle 1200 includes, for example, a front drive system 1201f, a rear drive system 1201r, a battery 1210 and a motor controller 1220 which are common to the front drive system 1201f and the rear drive system 1201r.

[0181] The front drive system 1201f includes a front inverter 3f, a front drive motor 4f, a front speed reducer 5f, a front rotation sensor 6f, a front current sensor 7f, a front drive shaft 8f, and a pair of front drive wheels 9af and 9bf. In addition, the rear drive system 1201r includes a rear inverter 3r, a rear drive motor 4r, a rear speed reducer 5r, a rear rotation sensor 6r, a rear current sensor 7r, a rear drive shaft 8r, and a pair of rear drive wheels 9ar and 9br.

[0182] The front inverter 3f and the rear inverter 3r correspond to the inverter 3 of the electric vehicle 100. The front drive motor 4f and the rear drive motor 4r correspond to the motor 4 of the electric vehicle 100. The front speed reducer 5f and the rear speed reducer 5r correspond to the speed reducer 5 of the electric vehicle 100. The front rotation sensor 6f and the rear rotation sensor 6r correspond to the rotation sensor 6 of the electric vehicle 100, and the front rotor phase αf and the rear rotor phase αr are respectively input to the motor controller 1220. The front current sensor 7f and the rear current sensor 7r correspond to the current sensor 7 of the electric vehicle 100, and the front current i uf 、i vf 、i wf and the subsequent current i ur 、i vr 、i wr The front drive shaft 8f and the rear drive shaft 8r correspond to the drive shaft 8 of the electric vehicle 100. The front drive wheels 9af, 9bf and the rear drive wheels 9ar, 9br correspond to the drive wheels 9a, 9b of the electric vehicle 100.

[0183] The battery 1210 is one or more batteries corresponding to the battery 1 of the electric vehicle 100. The battery 1210 supplies electric power to the front drive motor 4f and the rear drive motor 4r via the front inverter 3f and the rear inverter 3r, respectively, or receives input of regenerative electric power.

[0184] The motor controller 1220 corresponds to the motor controller 2 of the electric vehicle 100 , and controls the front drive system 1201 f and the rear drive system 1201 r in the same manner as the motor controller 2 of the electric vehicle 100 .

[0185] <Second Modification>

[0186] In the above-mentioned embodiments, the external disturbance torque estimated value T d ^ and set the gain K fb2 , K fb3 As a result, there is a scenario where the second feedback compensation value calculation unit 712 and / or the third feedback compensation value calculation unit 713 are substantially invalid. However, in principle, the second feedback compensation value calculation unit 712 and the third feedback compensation value calculation unit 713 are always valid. However, this is not limited to this, and the second feedback compensation value calculation unit 712 and the third feedback compensation value calculation unit 713 can be more clearly enabled or disabled according to the setting of the electric vehicle 100 performed by the driver, such as the selection of the driving mode.

[0187] Fig.15 : is a block diagram of the vibration reduction control involved in the second modification. Fig.15 In the vibration reduction control shown in FIG. 1 , a comprehensive switch 1501 is provided in the path for inputting the estimated external disturbance d^ to the second feedback compensation value calculation unit 712 and the third feedback compensation value calculation unit 713. The structure other than this is the same as that of the above-mentioned embodiment. The switch 1501 is turned on / off, for example, according to the selection of the driving mode of the electric vehicle 100. Therefore, in Fig.15 In the vibration damping control shown, compensation by the second feedback compensation value calculation unit 712 and the third feedback compensation value calculation unit 713 is enabled only when the additional vibration damping control is clearly enabled according to the selection of the driving mode.

[0188] Fig.16 : is a block diagram of the vibration reduction control involved in the second modification. Fig.16 In the vibration reduction control shown in FIG. 1 , switches 1502 and 1503 are respectively provided in the paths for inputting the estimated external disturbance d^ to the second feedback compensation value calculation unit 712 and the third feedback compensation value calculation unit 713. The structure other than this is the same as that of the above-mentioned embodiment. The switches 1502 and 1503 are turned on / off, for example, according to the selection of the driving mode of the electric vehicle 100. Therefore, in Fig.16 In the vibration reduction control shown, the second feedback compensation value calculation unit 712 is enabled only when the compensation function for the up-and-down vibration generated on a soft road surface such as sand is clearly activated according to the selection of the driving mode. In addition, the third feedback compensation value calculation unit 713 is enabled only when the compensation function for the vibration caused by the torque pulsation generated on an uphill road is clearly activated according to the selection of the driving mode.

[0189] As described above, the second feedback compensation value calculation unit 712 and / or the third feedback compensation value calculation unit 713 are clearly turned on / off according to the selection of the driving mode, etc., and the calculation load in the scene where the above compensation is not required is reduced. In addition, overcompensation can be reliably prevented.

[0190] As described above, the electric vehicle control method according to the present embodiment and the like is a method for controlling the electric vehicle 100 having the electric motor 4 as a driving source. In the electric vehicle control method, a target value related to the driving torque of the electric vehicle 100, that is, a torque target value (driving torque target value T ) is set based on vehicle information. m ). In addition, based on the parameter (rotation speed ω) indicating the rotation state of the motor 4 m ), and the basic feedback compensation value (estimated external disturbance d^) is calculated based on the transfer characteristic Gp(s) of the vehicle model of the electric vehicle 100. The basic feedback compensation value is multiplied by the first gain (K fb1 ) and calculate the first feedback compensation value (feedback compensation value C1). On the other hand, a predetermined specific frequency component is extracted from the basic feedback compensation value, and the specific frequency component is multiplied by the second gain (K fb2 or K fb3 ), thereby calculating the second feedback compensation value (feedback compensation value C2 or C3). The torque target value (drive torque target value T) is calculated based on the first feedback compensation value (feedback compensation value C1) and the second feedback compensation value (feedback compensation value C2 and / or C3). m ) is corrected, thereby the torque command value (final torque command value T mf ) is calculated. Then, the motor 4 is driven based on the torque command value thus calculated.

[0191] Thus, in the control method of the electric vehicle according to the present embodiment and the like, the motor 4 is driven based on the torque target value corrected not only based on the first feedback compensation value for compensating for the torsional vibration of the wheel drive system but also based on the second feedback compensation value for suppressing the vibration of the vehicle body caused by other factors. Therefore, in addition to the vibration of the vehicle body caused by the torsional vibration of the wheel drive system, the vibration of the vehicle body caused by factors other than the torsional vibration of the wheel drive system is also suppressed.

[0192] For example, when the driving resistance of the road is high due to driving on a soft road such as sandy land, or when a high torque is required when driving uphill, not only the torsional vibration of the wheel drive system but also the inherent vibration of the above driving scene can be reliably eliminated or reduced. As a result, the electric vehicle 100 can start and / or accelerate smoothly in the scene of driving on a soft road such as sandy land or uphill.

[0193] The control method of the electric vehicle according to the above-mentioned embodiment and the like is adjusted such that the gain K as the second gain is increased as the torque output by the electric motor 4 increases. fb2 and / or gain K fb3Thus, in a driving scenario where the torque output by the motor 4 is large, if the gain K as the second gain is fb2 and / or gain K fb3 If it is set to a larger value, it can achieve both driving performance and stability on soft roads such as sandy land and uphill roads, and suppress the torsional vibration of the wheel drive system and the inherent vibration in various driving scenarios.

[0194] In the control method of the electric vehicle involved in the above-mentioned embodiment, the specific frequency component is the natural vibration frequency component of the electric vehicle 100. In this way, the frequency component of the natural vibration generated in a specific driving scene is extracted as the specific frequency component, so that the natural vibration generated on soft roads such as sandy land and uphill roads can be reliably suppressed.

[0195] In the control method of the electric vehicle according to the above-mentioned embodiment, the specific frequency component includes at least a frequency component of the vertical vibration generated in the electric vehicle 100 according to the suspension characteristics of the tire and the vehicle body of the electric vehicle 100 and the sinking characteristics of the tire on a soft road surface such as sand (the vertical vibration frequency f of sand). sand ). Thus, in addition to the torsional vibration of the wheel drive system, at least the up-and-down vibration generated when driving on soft roads such as sandy land can be reliably compensated. In particular, when driving on sandy land among soft roads, the up-and-down vibration is likely to become significant, so it is preferred that the specific frequency component at least includes the up-and-down vibration frequency f of the sandy land. sand .

[0196] In the control method of the electric vehicle according to the above-mentioned embodiment, the specific frequency component includes at least the frequency component f of the torque ripple. x 、f y , according to the parameter representing the rotation state of the motor 4 (rotation speed ω m ) and changed. As a result, in driving scenarios such as uphill roads where the driving resistance is high and high torque is required, vibrations caused by torque pulsation can be reliably suppressed.

[0197] In the control method of the electric vehicle involved in the above-mentioned embodiment, it is preferred that the specific frequency component includes multiple frequency components. As the specific frequency component, when multiple frequency components are extracted, the vibrations of the above-mentioned frequency components are reliably suppressed respectively. In particular, the torque pulsation generated in the driving scene such as uphill road, where the driving resistance is high and high torque is required, generates multiple torque pulsations such as X times and Y times. Therefore, as described above, the specific frequency component includes multiple frequency components corresponding to X times and Y times, etc., so that the vibration caused by the torque pulsation can be particularly reliably suppressed.

[0198] In the above-mentioned embodiments, the external disturbance torque estimated value T d^、Drive torque target value T m , or the final torque command value T mf The absolute value of the torque command value is compared with the predetermined threshold values ​​Th1 and Th2, thereby determining the driving scene in which the absolute value of the torque command value is greater than or equal to the threshold values ​​Th1 and Th2. Moreover, when the absolute value of the torque command value is greater than or equal to the threshold values ​​Th1 and Th2, the feedback compensation values ​​C2 and C3 as the second feedback compensation values ​​are calculated.

[0199] The natural vibrations shown in specific driving scenarios such as sandy land and uphill roads are generally easy to occur when high torque is required. Therefore, as described above, in the driving scenario requiring high torque, if the feedback compensation values ​​C2 and C3 as the second feedback compensation value are calculated, the natural vibrations generated only in the specific driving scenario can be easily and reliably suppressed.

[0200] In the above embodiment, in particular, based on the torque command value (final torque command value T mf ) and a parameter indicating the rotation state of the motor 4 (rotation speed ω m ), an estimated value of the external disturbance torque acting on the electric vehicle 100, namely, an estimated value of the external disturbance torque T d Then, the external disturbance torque estimated value T d The absolute value of ^ is compared with the predetermined thresholds Th1 and Th2 to determine the external disturbance torque estimated value T d The absolute value of ^ is greater than or equal to the above thresholds Th1 and Th2. d When the absolute value of ^ is greater than or equal to the threshold values ​​Th1, Th2, feedback compensation values ​​C2, C3 are calculated as the second feedback compensation values.

[0201] In this way, based on the external disturbance torque estimated value T d ^ In order to determine a driving scene with high driving resistance, if the feedback compensation values ​​C2 and C3 as the second feedback compensation values ​​are calculated in the driving scene with high driving resistance, it is possible to particularly accurately determine a specific driving scene with high driving resistance such as sandy land and uphill roads. As a result, the natural vibration shown in the specific driving scene such as sandy land and uphill roads can be particularly reliably suppressed.

[0202] The embodiments of the present invention have been described above, but the configurations described in the above embodiments and various modifications are merely examples of application of the present invention and are not intended to limit the technical scope of the present invention.

[0203] For example, in the above-mentioned embodiment and the like, the rotation speed ω is used as a parameter indicating the rotation state of the motor 4. m, but it can also replace the rotation speed ω m The speed N m Parameters related to the rotation state of the motor 4, such as the above, are used for vibration reduction control and the like.

Claims

1. A control method for an electric vehicle having an electric motor as a driving source, wherein: a torque target value, which is a target value related to the driving torque of the electric vehicle, is set based on the vehicle information; calculating a basic feedback compensation value based on a parameter representing a rotation state of the electric motor and a vehicle model of the electric vehicle, multiplying the basic feedback compensation value by a first gain to calculate a first feedback compensation value, extracting a predetermined specific frequency component from the basic feedback compensation value, multiplying the specific frequency component by a second gain to calculate a second feedback compensation value, The torque target value is corrected by using the first feedback compensation value and the second feedback compensation value to calculate a final torque command value. The electric motor is driven based on the final torque command value.

2. The control method of an electric vehicle according to claim 1, wherein: The second gain is adjusted to be larger as the torque output by the electric motor is larger.

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

4. The control method of the electric vehicle according to claim 3, wherein: The specific frequency component includes at least a frequency component of vertical vibration generated in the electric vehicle due to suspension characteristics of the tire and a vehicle body of the electric vehicle and sinking characteristics of the tire on a soft road surface.

5. The control method of the electric vehicle according to claim 3, wherein: The specific frequency component includes at least a frequency component of torque ripple, and changes according to the parameter.

6. The control method of the electric vehicle according to claim 3, wherein: The specific frequency component includes a plurality of frequency components.

7. The control method of an electric vehicle according to claim 1 or 2, wherein: The absolute value of the torque command value is compared with a predetermined threshold value to determine a driving scenario in which the absolute value of the torque command value is greater than or equal to the threshold value. When the absolute value of the torque command value is greater than or equal to the threshold value, the second feedback compensation value is calculated.

8. The control method of an electric vehicle according to claim 1 or 2, wherein: Based on the torque command value and the parameter, a disturbance torque estimation value, which is an estimation value of the disturbance torque acting on the electric vehicle, is calculated; comparing the absolute value of the estimated external disturbance torque value with a predetermined threshold value to determine a driving scenario in which the absolute value of the estimated external disturbance torque value is greater than or equal to the threshold value, When the absolute value of the external disturbance torque estimated value is greater than or equal to the threshold value, the second feedback compensation value is calculated.

9. A control device for an electric vehicle having an electric motor as a driving source, wherein: The control device of the electric vehicle comprises: a torque target value setting unit that sets a torque target value that is a target value related to the driving torque of the electric vehicle based on vehicle information; a basic feedback compensation value calculation unit that calculates a basic feedback compensation value based on a parameter indicating a rotation state of the electric motor and a vehicle model of the electric vehicle; a first feedback compensation value calculation unit configured to calculate a first feedback compensation value by multiplying the basic feedback compensation value by a first gain; a second feedback compensation value calculation unit that extracts a predetermined specific frequency component from the basic feedback compensation value, and calculates a second feedback compensation value by multiplying the specific frequency component by a second gain; a torque command value calculation unit that calculates a final torque command value by correcting the torque target value using the first feedback compensation value and the second feedback compensation value; and A drive control unit drives the electric motor based on the final torque command value.

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