JP4765939B2 - Electric vehicle - Google Patents

Description

  The present invention relates to an electric vehicle, and more particularly to an electric vehicle equipped with an electric motor for generating vehicle driving force.

  In an electric vehicle equipped with an electric motor for generating vehicle driving force (hereinafter simply referred to as an electric motor) such as an electric vehicle or a hybrid vehicle, an output torque linear with respect to an accelerator pedal stroke (accelerator opening) can be generated by the electric motor. Therefore, there is an advantage that a torque characteristic that matches the acceleration operation of the driver can be realized, and driving feeling is improved. On the other hand, when the road surface condition is bad due to snow accumulation, freezing, etc., there is a tendency that slip is likely to occur because the low rotational torque is large in traveling by the motor output, and the accelerator operation is difficult.

  For this reason, for example, in Japanese Patent Application Laid-Open No. 2005-124287 (Patent Document 1), as a vehicle drive control device that improves acceleration performance and climbing performance while suppressing occurrence of slip, the accelerator opening degree is reduced on a low μ road. When it is determined that the temporal change is small, a configuration is disclosed in which the target motor torque used for torque control of the electric motor is vibrated and changed sinusoidally.

  According to the vehicle drive control device disclosed in Patent Document 1, when driving on a low μ road, the driving force actually applied to the wheels is vibrated within a predetermined torque range in accordance with the driver's accelerator operation amount. Can be changed. Thereby, it is possible to ensure acceleration performance and climbing performance by using the maximum possible torque while suppressing slip continuation by periodically switching between increase and decrease in torque.

  Japanese Patent Laying-Open No. 2004-112973 (Patent Document 2) discloses a vehicle for preventing a driving torque of a driving wheel from being limited due to erroneous detection of slip when detecting slip based on angular acceleration. A slip control device is disclosed. Specifically, when the torque change amount of the motor required torque exceeds a threshold value, the angular acceleration temporarily increases due to the torque change, and there is a risk of erroneously determining that a slip has occurred even though no slip has occurred. In such a case, a control configuration is disclosed in which torque limiting processing is not executed even if slip is determined based on angular acceleration.

Further, in Japanese Patent Laid-Open No. 9-158752 (Patent Document 3), in the acceleration slip control by the engine output control, when the acceleration slip is detected, the control amount of the engine output is vibrated and the vibration time is set to the slip state. There is disclosed a vehicle acceleration slip control device which is changed accordingly. According to this, it is possible to perform appropriate control according to the slip state, and to improve the startability on the low μ road.
JP 2005-124287 A JP 2004-112973 A JP-A-9-158752

  In an electric vehicle, when the accelerator pedal is stepped on suddenly by the driver, the required torque for the electric motor increases rapidly in response to a rapid increase in the accelerator opening. However, from the viewpoint of preventing the occurrence of slip as described above, it is impossible to immediately increase the torque command value following the increase in acceleration demand by the driver. For this reason, it is necessary to limit the increase rate of the output command of the motor in consideration of the relationship between the output torque of the vehicle driving motor and the grip force of the tire. Therefore, when such a sudden increase in the accelerator opening is caused, it is a problem to promptly respond to the driver's acceleration request, that is, the request to increase the output torque of the motor, while preventing the occurrence of slip.

  Although the vehicle drive control device of Patent Document 1 can achieve the suppression of slip generation on a low μ road, it is related to torque control when the time change of the accelerator opening is small, and the driver suddenly presses the accelerator. No mention is made of what to do when you step in. This also applies to Patent Document 2.

  Patent Document 3 relates to engine output control, and does not disclose any torque control of a motor for generating vehicle driving force of an electric vehicle. Furthermore, the output control is also a countermeasure when detecting an acceleration slip, and there is no mention of a control configuration for quickly increasing the output torque while preventing the slip.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to generate slip when the required torque to the motor for generating vehicle driving force is rapidly increased by the accelerator operation by the driver. It is an object to provide an electric vehicle capable of quickly increasing the output torque of an electric motor while preventing the above.

  An electric vehicle according to the present invention includes an electric motor that generates vehicle driving force, a power conversion unit that controls driving of the electric motor according to a torque command value, and a control device. The control device generates a torque command value according to the required output torque to the electric motor based on the vehicle state and the accelerator opening operation by the driver. In particular, the control device is configured to include a torque command value increase limiting unit that increases the torque command value toward the required output torque while vibrating the torque command value when the increase rate of the required output torque exceeds a predetermined determination value. The

  According to the above-described electric vehicle, when the required output torque to the vehicle driving force generation motor suddenly increases due to a sudden accelerator depression by the driver, the torque command value is vibrated, that is, the torque is increased and decreased periodically. The torque command value can be raised so as to follow the sudden increase in the required output torque to the electric motor while ensuring the grip force by the wheels by switching. Thereby, as compared with the case where the torque command value is increased without vibration, the output torque of the electric motor can be quickly increased while preventing the occurrence of slipping to ensure acceleration performance.

  Preferably, the torque command value increase limiting unit includes an average value setting unit, a vibration setting unit, and an adding unit. The average value setting means increases the average value of the torque command values toward the required output torque according to a predetermined limit rate. Based on the vibration setting means and the vehicle state, the amplitude and frequency of the vibration component of the torque command value are set. The adding means sets the torque command value of the electric motor according to the sum of the average value set by the average value setting means and the vibration component set by the vibration setting means.

  In particular, the vibration setting means sets at least one of the amplitude and frequency of the vibration component of the torque command value based on the accelerator opening. Alternatively, the control device further includes a road surface state estimating unit that estimates a friction coefficient of a road surface on which the electric vehicle is traveling, and the vibration setting unit estimates at least one of an amplitude and a frequency of a vibration component of the torque command value. It sets based on the friction coefficient estimated by the means.

  With such a configuration, it is possible to set at least one of the amplitude and the frequency of the vibration component of the torque command value based on the vehicle state, for example, the accelerator opening and / or the road friction coefficient during traveling. As a result, it is possible to appropriately set the vibration component of the torque command value and quickly increase the output torque of the electric motor while preventing the occurrence of slipping, thereby ensuring acceleration performance.

  Preferably, the control device further includes an idling detection means for detecting idling of the wheel of the electric vehicle, and a slip avoidance means for suppressing a torque command value during the idling of the wheel of the electric vehicle. Then, the control device, when setting the torque command value by the torque command value increase limiting means, detects the wheel idling of the electric vehicle by the idling detection means, and when the wheel idling occurs, the slip avoidance means Set to lower than.

  By adopting such a configuration, it is possible to prevent the occurrence of continuous slip by so-called traction control by the slip avoiding means when the wheel idling (slip) occurs. For this reason, it is possible to promptly increase the torque command value by superimposing the vibration components, and to recover quickly from the slip state even if a slip occurs.

  According to the electric vehicle of the present invention, when the required torque of the vehicle driving force generating motor is suddenly increased by the accelerator operation by the driver, the output torque of the motor can be quickly increased while preventing the occurrence of slipping.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the following, the same or corresponding parts in the drawings are denoted by the same reference numerals, and the description thereof will not be repeated in principle.

  FIG. 1 is a configuration diagram related to a motor for driving a vehicle of an electric vehicle according to an embodiment of the present invention.

  Referring to FIG. 1, electrically powered vehicle 100 according to the embodiment of the present invention includes a DC voltage generation unit 10 #, a smoothing capacitor C0, an inverter 20, a control circuit 50, a motor generator MG, and a motor generator MG. It includes a drive shaft 62 that is coupled so as to be able to transmit output torque, and drive wheels 65 that are rotationally driven as the drive shaft 62 rotates. The driving wheel 65 is provided with a wheel speed sensor 67. In addition, you may provide the wheel speed sensor 67 in each wheel containing a non-driving wheel.

  Motor generator MG is mounted on an electric vehicle such as a hybrid vehicle or an electric vehicle, and is used as a “motor” for driving a vehicle that generates a driving torque of wheels. Alternatively, motor generator MG may be configured to have a function of a generator driven by an engine, and perform regenerative power generation by generating an output torque in a direction opposite to the rotation direction of drive wheels 65. You may be comprised so that it may have a function to an electric motor and a generator.

  DC voltage generation unit 10 # includes a DC power supply B, system relays SR1 and SR2, a smoothing capacitor C1, and a step-up / down converter 12.

  As the DC power source B, a secondary battery such as nickel hydride or lithium ion, or a power storage device such as an electric double layer capacitor can be applied. The DC voltage Vb output from the DC power source B is detected by the voltage sensor 10. Voltage sensor 10 outputs detected DC voltage Vb to control circuit 50.

  System relay SR1 is connected between the positive terminal of DC power supply B and power supply line 6, and system relay SR2 is connected between the negative terminal of DC power supply B and ground line 5. System relays SR1 and SR2 are turned on / off by a signal SE from control circuit 50. More specifically, the system relays SR1 and SR2 are turned on by an H (logic high) level signal SE from the control circuit 50 and turned off by an L (logic low) level signal SE from the control circuit 50. Smoothing capacitor C <b> 1 is connected between power supply line 6 and ground line 5.

  Buck-boost converter 12 includes a reactor L1 and power semiconductor switching elements Q1, Q2. Power semiconductor switching elements Q 1 and Q 2 are connected in series between power supply line 7 and ground line 5. On / off of power semiconductor switching elements Q 1 and Q 2 is controlled by switching control signals S 1 and S 2 from control circuit 50.

  In the embodiments of the present invention, an IGBT (Insulated Gate Bipolar Transistor), a power MOS (Metal Oxide Semiconductor) transistor, or a power bipolar transistor is used as a power semiconductor switching element (hereinafter simply referred to as “switching element”). Etc. can be used. Anti-parallel diodes D1, D2 are arranged for switching elements Q1, Q2.

  Reactor L1 is connected between a connection node of switching elements Q1 and Q2 and power supply line 6. The smoothing capacitor C 0 is connected between the power supply line 7 and the ground line 5.

  Inverter 20 includes a U-phase arm 22, a V-phase arm 24, and a W-phase arm 26 provided in parallel between power supply line 7 and ground line 5. Each phase arm is composed of a switching element connected in series between the power supply line 7 and the ground line 5. For example, U-phase arm 22 includes switching elements Q11 and Q12, V-phase arm 24 includes switching elements Q13 and Q14, and W-phase arm 26 includes switching elements Q15 and Q16. Further, antiparallel diodes D11 to D16 are connected to switching elements Q11 to Q16, respectively. Switching elements Q11 to Q16 are turned on / off by switching control signals S11 to S16 from control circuit 50.

  An intermediate point of each phase arm is connected to each phase end of each phase coil of motor generator MG. That is, motor generator MG is a three-phase permanent magnet motor, and is configured such that one end of three coils of U, V, and W phases is commonly connected to neutral point N. Furthermore, the other end of each phase coil is connected to the midpoint of the switching elements of each phase arm 22, 24, 26.

  In the step-up / down converter 12, the DC voltage VH obtained by boosting the DC voltage Vb supplied from the DC power supply B (this DC voltage corresponding to the input voltage to the inverter 20 is hereinafter also referred to as “system voltage VH”). Is supplied to the inverter 20. This system voltage corresponds to the DC link voltage of the inverter mentioned in Patent Document 1.

  More specifically, in response to the switching control signals S1 and S2 from the control circuit 50, the duty ratio (on-period ratio) of the switching elements Q1 and Q2 is set, and the boost ratio is determined according to the duty ratio. Become.

  Further, during the step-down operation, the step-up / down converter 12 steps down the DC voltage (system voltage) supplied from the inverter 20 via the smoothing capacitor C0 and charges the DC power supply B. More specifically, in response to the switching control signals S1 and S2 from the control circuit 50, a period in which only the switching element Q1 is turned on and a period in which both the switching elements Q1 and Q2 are turned off are alternately provided. The step-down ratio is in accordance with the duty ratio during the ON period.

  Smoothing capacitor C <b> 0 smoothes the DC voltage from step-up / down converter 12 and supplies the smoothed DC voltage to inverter 20. The voltage sensor 13 detects the voltage across the smoothing capacitor C 0, that is, the system voltage, and outputs the detected value VH to the control circuit 50.

  When the torque command value of motor generator MG is positive (Tqcom> 0), inverter 20 performs smoothing capacitor C0 by switching operation of switching elements Q11 to Q16 in response to switching control signals S11 to S16 from control circuit 50. Motor generator MG is driven so as to convert the DC voltage supplied from AC to AC voltage and output a positive torque. Further, when the torque command value of motor generator MG is zero (Tqcom = 0), inverter 20 converts the DC voltage to the AC voltage by the switching operation in response to switching control signals S11 to S16, and the torque is zero. The motor generator MG is driven so that Thereby, motor generator MG is driven to generate zero or positive torque designated by torque command value Tqcom.

  Furthermore, during regenerative braking of electrically powered vehicle 100, torque command value Tqcom of motor generator MG is set to a negative value (Tqcom <0). In this case, inverter 20 converts the AC voltage generated by motor generator MG into a DC voltage by a switching operation in response to switching control signals S11 to S16, and converts the converted DC voltage (system voltage) to smoothing capacitor C0. To the step-up / down converter 12. Note that regenerative braking here refers to braking with regenerative power generation when the driver driving a hybrid vehicle or electric vehicle performs foot braking, or turning off the accelerator pedal while driving, although the foot brake is not operated. This includes decelerating the vehicle (or stopping acceleration) while generating regenerative power.

  Current sensor 27 detects motor current MCRT flowing through motor generator MG, and outputs the detected motor current to control circuit 50. Since the sum of instantaneous values of the three-phase currents iu, iv, and iw is zero, the current sensor 27 has two phases of motor current (for example, V-phase current iv and W-phase current iw) as shown in FIG. It is sufficient to arrange it so as to detect.

  The rotation angle sensor (resolver) 28 detects a rotation angle θ of a rotor (not shown) of the motor generator MG and sends the detected rotation angle θ to the control circuit 50. The control circuit 50 can calculate the rotational speed Nmt (rotational angular velocity ω) of the motor generator MG based on the rotational angle θ.

  The control device 80 is input with battery information indicating the charging state of the battery B and input / output power limitation, and various vehicle sensor inputs (for example, wheel speed, road gradient, etc.). The accelerator pedal 70 operated by the driver is provided with an accelerator opening sensor 75, and the accelerator opening detected by the accelerator opening sensor 75 is input to the control device 80. Control device 80 generates torque command value Tqcom and regeneration instruction signal RGE for motor generator MG based on the vehicle state and the accelerator opening operation by the driver. Note that the control device 80 is within a range in which overcharge or overdischarge of the DC power supply B does not occur based on information on the DC power supply B, such as a charge rate (SOC: State of Charge) or an inputable power Win indicating charging limitation. Thus, the torque command value Tqcom and the regeneration instruction signal RGE are generated.

  A motor control circuit (MG-ECU) 50 includes a torque command value Tqcom input from the control device 80, a battery voltage Vb detected by the voltage sensor 10, a system voltage VH detected by the voltage sensor 13, and a current sensor. Based on the motor current MCRT 27 and the rotation angle θ from the rotation angle sensor 28, the operations of the step-up / down converter 12 and the inverter 20 are controlled so that the motor generator MG outputs a torque according to the torque command value Tqcom. Switching control signals S1, S2, S11 to S16 are generated. That is, the control device 80 corresponds to a host ECU of the control circuit (MG-ECU) 50.

  As described above, in the configuration shown in FIG. 1, the buck-boost converter 12, the inverter 40, and the control circuit 50 constitute a “power conversion unit (PCU)” that drives and controls the motor generator MG according to the torque designation value Tqcom.

  During the step-up operation of buck-boost converter 12, control circuit 50 calculates a command value for system voltage VH according to the operating state of motor generator MG, and based on this command value and the detected value of system voltage VH by voltage sensor 13. The switching control signals S1 and S2 are generated so that the output voltage VH becomes a voltage command value.

  In addition, when receiving a control signal RGE indicating that the hybrid vehicle or the electric vehicle has entered the regenerative braking mode from the control device 80, the control circuit 50 converts the AC voltage generated by the motor generator MG into a DC voltage. Switching control signals S11 to S16 are generated and output to inverter 20. Thereby, inverter 20 converts the regenerative power from motor generator MG into a DC voltage and supplies it to buck-boost converter 12.

  Further, in response to control signal RGE, control circuit 50 generates switching control signals S 1 and S 2 so as to step down the DC voltage supplied from inverter 20, and outputs it to buck-boost converter 12. In this way, the regenerative power from the motor generator MG is used for charging the DC power supply B.

  Further, control circuit 50 generates signal SE for turning on / off system relays SR1 and SR2 and outputs the system relays SR1 and SR2 when drive system of electric vehicle 100 is started / stopped.

  Next, torque command value setting when the accelerator is depressed in the electric vehicle 100 will be described.

  FIG. 2 shows a conventional torque command value setting when the accelerator is depressed. FIG. 2 shows an example of a waveform when the driver depresses the accelerator pedal to a state close to the fully open state.

  Referring to FIG. 2, the required output torque Trq to motor generator MG increases rapidly in response to the rapid increase in accelerator opening. In a hybrid vehicle, after the required driving force for the entire vehicle is obtained based on the current vehicle state such as the vehicle speed and the acceleration request (accelerator opening) by the driver, the engine is considered in consideration of the energy efficiency of the entire vehicle. Further, by determining the output distribution among the motor generators MG, the required output torque Trq of the motor generator MG is set. In the electric vehicle, the required output torque to motor generator MG is directly set according to the accelerator opening.

  Here, if the torque command value Tqcom is immediately increased following the rapid increase in the required output torque Trq, the driving force is rather reduced due to the occurrence of wheel slipping (slip) due to a sudden torque change. It becomes unstable. Therefore, as shown in FIG. 2, the torque command value Tqcom is set so as to increase toward the required output torque Trq after limiting the increase rate. Note that the follow-up delay of the torque command value Tqcom due to such an increase rate limit is usually less than 1 second (in the order of several hundred ms).

  As shown in FIG. 3, the control device 80 has a traction control function, and when slip is detected based on the wheel speed or the like at time t0, slip detection until the slip is eliminated. During the period (time t0 to t1), the torque command value Tqcom is suppressed. For example, the torque command value Tqcom is controlled so as to gradually decrease from the setting of the slip occurrence time (time t0) until the slip is eliminated. When the slip is eliminated (after time t1), the torque command value Tqcom is gradually increased toward the required output torque Trq again in accordance with the increase limit rate similar to that in FIG.

  That is, it is possible to perform control to recover from the slip state when slip occurs by traction control, but once slip occurs, the follow-up delay of the torque command value Tqcom with respect to the increase in the required output torque Trq increases. End up. For this reason, it has been difficult to increase the increase limit rate. On the other hand, it is necessary to increase the output torque of the motor generator MG as quickly as possible when the accelerator opening is rapidly increased, which is strongly demanded by the driver.

  Therefore, as shown in FIG. 4, in the electric vehicle according to the present embodiment, when the required output torque Trq to motor generator MG increases beyond a predetermined rate due to a sudden accelerator depression by the driver, a torque command The value Tqcom is increased toward the required output torque Trq while vibrating. That is, the torque command value Tqcom is set as the sum of the average value T1 and the vibration component (AC component).

  Average value T1 is increased toward required output torque Trq in accordance with a predetermined limit rate. However, the increase limit rate of the average value T1 is set more gently than the conventional increase limit rate of the torque command value described in FIG. Here, Tqcom # in FIG. 4 indicates the setting of the torque command value according to the conventional limit rate in FIG.

  By controlling the output torque of motor generator MG according to torque command value Tqcom set in this way, it is possible to improve the wheel grip force by alternately generating a torque increase period and a decrease period. In particular, since the quick response of the output torque control of the electric motor is higher than that of the engine, the slip resistance during sudden acceleration can be effectively improved. For this reason, it is possible to secure the vehicle driving force (acceleration) in response to the driver's acceleration request by increasing the increase rate of the average value T1 of the torque command value Tqcom as compared with the conventional (Tqcom #).

  Further, the maximum torque line Tmax is obtained in advance corresponding to the slip limit, and the instantaneous value (= average value + vibration component) of the vibration torque command value Tqcom is limited so as not to exceed Tmax at each timing. Thus, it is possible to further ensure the prevention of slip occurrence.

  Next, a control configuration by the control device 80 for realizing the torque command value setting as shown in FIG. 4 will be described.

  FIG. 5 is a functional block diagram illustrating torque command value setting according to the embodiment of the present invention. Each functional block shown in FIG. 5 is realized by hardware processing or software processing by the control device 80.

  Referring to FIG. 5, control device 80 includes a torque command value increase limiting unit 200. Torque command value increase limiting unit 200 typically sets a predetermined increase rate of the accelerator opening by the driver's accelerator operation when the rate of increase in required output torque Trq to motor generator MG exceeds a predetermined determination value. The operation is started when the determination value is exceeded, and the operation is terminated when the torque command value Tqcom follows the required output torque Trq.

  Torque command value increase restriction unit 200 includes an average value setting unit 210, a vibration setting unit 220, an addition unit 230, and an upper limit check unit 240.

  Based on the required output torque Trq and the previous torque command value Tqcom, the average value setting unit 210 averages the torque command value so that the torque command value Tqcom increases toward the required output torque Trq according to a predetermined increase limit rate. Set T1.

  The vibration setting unit 220 sets a vibration component (AC component) T2 of the torque command value Tqcom. The period T (T = 1 / f, f: frequency) of the vibration component and its amplitude Am are determined based on the vehicle state, typically based on the accelerator opening. The adding unit 230 obtains the sum (T1 + T2) of the average value T1 set by the average value setting unit 210 and the vibration component T2 set by the vibration setting unit 220.

  Upper limit check unit 240 limits torque command value Tqcom so as not to exceed maximum torque line Tmax shown in FIG. Specifically, when T1 + T2 obtained by the adding unit 230 exceeds Tmax, Tqcom = Tmax is set.

  Or as shown in FIG. 6, the control apparatus 80 may be comprised so that the road surface condition estimation part 250 may be further included. The road surface state estimation unit 250 estimates the road surface friction coefficient μ currently traveling from the slip state of each wheel during traveling, the relationship between the applied driving force and the actual wheel speed, or the like. Alternatively, the road surface friction coefficient μ may be obtained by providing means for measuring the road surface friction coefficient μ.

  The vibration setting unit 220 sets at least one of the period T and the amplitude Am of the vibration component T2 according to the accelerator opening and / or the road surface friction coefficient μ. Further, the setting of the maximum torque line Tmax in the upper limit check unit 240 can also reflect the road surface friction coefficient μ. Specifically, when the road surface friction coefficient μ is low, the slip prevention effect can be enhanced by setting the maximum torque line Tmax to be relatively low.

  By the operation of the control device 80 according to the functional block diagrams shown in FIGS. 5 and 6, as shown in FIG. 4, it is possible to quickly increase the torque command value Tqcom while oscillating when the accelerator opening degree suddenly increases. .

  FIG. 7 is a flowchart for realizing the torque command value setting in the electric vehicle according to the embodiment of the present invention described with reference to FIGS. A program for performing control processing according to the flowchart shown in FIG. 7 is stored in advance in control device 80 and executed at predetermined intervals.

  Referring to FIG. 7, in step S100, control device 80 detects the accelerator opening based on the output of accelerator opening sensor 75, and requests output torque Trq to motor generator MG based on the vehicle state and the accelerator opening. To decide.

  Further, in step S120, control device 80 determines whether or not required output torque Trq is rapidly increasing at a rate equal to or higher than a predetermined determination value. Alternatively, based on the accelerator opening detected in step S100, the determination in step S120 is performed based on whether the increase rate of the accelerator opening is greater than a predetermined determination value, that is, whether a rapid acceleration request is generated by the driver. May be. As described above, in step S120, it is determined whether or not the operation start condition of the torque command value increase limiting unit 200 shown in FIGS. Once step S120 is determined to be YES, YES is determined in step S120 until the torque command value Tqcom follows the required output torque Trq, that is, until the operation end condition of the torque command value increase limiting unit 200 is satisfied. Judgment is maintained.

  When YES is determined in step S120, that is, when the acceleration request is large, control device 80 increases torque command value Tqcom following request output torque Trq according to a predetermined limit rate for sudden acceleration in step S140. Thus, torque command average value T1 is determined. Further, control device 80 determines vibration component T2 of torque command value Tqcom in step S160, and in step S180, the sum of average value T1 obtained in step S140 and vibration component T2 obtained in step S160, that is, Torque command value Tqcom is set by superimposing vibration component T2 on average value T1.

  Further, in step S190, control device 80 performs an upper limit check so that torque command value Tqcom set in step S180 does not exceed maximum torque line Tmax (FIG. 4). Through these series of processes, the torque command value Tqcom at the time of rapid acceleration is set.

  As shown in FIGS. 5 and 6, the setting of the vibration component T2 of the torque command value in step S160 is appropriately set reflecting the vehicle state such as the accelerator opening and the road surface friction coefficient μ during traveling. It is preferable to do.

  On the other hand, control device 80 changes torque command value Tqcom toward required output torque Trq in accordance with a predetermined limit rate at normal time in step S200 when NO is determined in step S120, that is, when there is no request for rapid acceleration. Let In this case, torque command value Tqcom is set so as to follow the required output torque Trq in accordance with the normal increase limit rate corresponding to Tqcom # shown in FIG. 4 without including a vibration component.

  In the flowchart of FIG. 7, the process in step S140 corresponds to the function in the average value setting unit 210 in FIGS. 5 and 6, and the process in step S160 is performed in the vibration setting unit 220 in FIGS. Decide on processing. Further, the process in step S180 corresponds to the function of the adding unit 230 in FIGS. 5 and 6, and the process in step S190 corresponds to the function of the upper limit check unit 240 in FIGS.

[Modification]
FIG. 8 is a functional block diagram for explaining torque command value setting when the accelerator is depressed in an electric vehicle according to a modification of the embodiment of the present invention.

  As understood from the comparison between FIG. 8 and FIG. 5, in the torque command value setting of the electric vehicle according to the modification of the embodiment, in addition to the configuration in FIG. 5, the slip detection unit 300, the setting switching unit 310, and the traction A control unit 320 is further provided.

  The slip detection unit 300 detects the occurrence of slip of each wheel based on an abrupt change in the rotational angular velocity based on the output of a wheel speed sensor (not shown) provided on each wheel. The traction control unit 320 sets the torque command value Tqcom in the slip detection period shown in FIG. For example, once a slip is detected, traction control unit 320 suppresses torque command value Tqcom in a manner that gradually decreases during the period until the slip is eliminated.

  Setting switching unit 310 switches the setting of torque command value Tqcom based on the determination result of slip detection unit 300. Specifically, the setting switching unit 310 sets the torque command value Tqcom in the same manner as in FIGS. 5 and 6 when the slip detection unit 300 does not detect the slip, and sets the torque command value Tqcom.

  On the other hand, the setting switching unit 310 selects the route II during slip detection by the slip detection unit 300. In this case, the torque command value Tqcom is set by the traction control unit 320 so as to gradually decrease from the point of occurrence of slip without vibration.

  FIG. 9 is a flowchart for realizing the torque command value setting in the electric vehicle according to the modification of the embodiment of the present invention shown in FIG. The program for performing the control process according to the flowchart shown in FIG. 9 is also stored in advance in control device 80 and executed at predetermined intervals.

  Referring to FIG. 9, in step S300, control device 80 performs the torque command value setting described in FIGS. 5 and 6 in steps S100 to S200 shown in FIG. Then, in step S310, control device 80 determines whether or not slip detection is being performed. When slip does not occur (NO in step S310), setting in step S300 is performed as a torque command in step S340. Used as the value Tqcom. This corresponds to the operation when the setting switching unit 310 selects the route I in FIG.

  On the other hand, control device 80 turns on traction control and suppresses torque command value Tqcom with respect to the torque command value setting in step S300 during slip generation (when YES is determined in step S310). . This corresponds to the operation when the setting switching unit 310 selects the route II in FIG.

  By adopting such a control configuration, when the required output torque Trq of the motor generator MG increases rapidly due to a rapid acceleration request, as shown in FIGS. The command value Tqcom can be increased, and even in the event of a slip, the traction control can be applied to quickly avoid the slip state without causing a continuous slip. It becomes.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

It is a block diagram relevant to the motor for a vehicle drive of the electric vehicle by embodiment of this invention. It is a wave form diagram explaining the conventional torque command value setting at the time of accelerator depression. It is a wave form diagram explaining torque command value setting at the time of slip generation. It is a wave form diagram explaining the torque command value setting at the time of accelerator depression in the electric vehicle by embodiment of this invention. FIG. 5 is a first block diagram illustrating torque command value setting when the accelerator is depressed in the electric vehicle according to the embodiment of the present invention. It is a 2nd block diagram explaining the torque command value setting at the time of accelerator depression in the electric vehicle by embodiment of this invention. It is a flowchart which implement | achieves the torque command value setting in the electric vehicle by embodiment of this invention. It is a block diagram explaining the torque command value setting at the time of accelerator depression in the electric vehicle by the modification of embodiment of this invention. It is a flowchart which implement | achieves the torque command value setting in the electric vehicle by the modification of embodiment of this invention.

Explanation of symbols

  5 Ground line, 6, 7 Power line, 10, 13 Voltage sensor, 10 # DC voltage generator, 12 Buck-boost converter, 20 Inverter, 22, 24, 26 Each phase arm, 27 Current sensor, 28 Rotation angle sensor, 50 Control circuit, 62 drive shaft, 65 drive wheel, 70 accelerator pedal, 75 accelerator opening sensor, 80 control device, 100 electric vehicle, 200 torque command value increase limiting unit, 210 average value setting unit, 220 vibration setting unit, 230 addition Unit, 240 upper limit check unit, 250 road surface condition estimation unit, 300 slip detection unit, 310 setting switching unit, 320 traction control unit, B DC power supply, C0, C1 smoothing capacitor, D1, D2, D11 to D16 antiparallel diode, iu , Iv, iw Phase current, L1 reactor, MCRT mode Current, MG Motor generator, N neutral point, Nmt Motor generator rotation speed, Q1, Q2, Q11 to Q16 Power semiconductor switching element, RGE control signal (regenerative instruction), S1, S2, S11 to S16 switching control signal, SR1 , SR2 System relay, T1 torque command average value, T2 torque command vibration component, Tmax maximum torque line, Tqcom torque command value, Trq required output torque, Vb battery voltage, VH system voltage, θ rotation angle, μ Road surface friction coefficient.

Claims (4)

An electric motor for generating vehicle driving force;
A power conversion unit that drives and controls the electric motor according to a torque command value;
A control device for generating the torque command value according to a required output torque to the electric motor based on a vehicle state and an accelerator opening operation by a driver;
The controller is
When the increase rate of the required output torque exceeds a predetermined judgment value, look including a torque command value increases limiting means for increasing towards the required output torque while vibrating the torque command value,
The torque command value increase limiting means is
An average value setting means for increasing an average value of the torque command values toward the required output torque according to a predetermined limit rate ;
Vibration setting means for setting the amplitude and frequency of the vibration component of the torque command value based on the vehicle state ;
An electric vehicle comprising: an adding means for setting the torque command value of the electric motor according to a sum of the average value set by the average value setting means and the vibration component set by the vibration setting means . The vibration setting means, at least one of the amplitude and frequency of the vibration component of the torque command value is set based on the accelerator opening, an electric vehicle according to claim 1. The controller is
Road surface condition estimating means for estimating a friction coefficient of a road surface on which the electric vehicle is running;
The vibration setting means, wherein at least one of the amplitude and frequency of the vibration component of the torque command value is set based on the friction coefficient estimated by the road surface condition estimation unit, an electric vehicle according to claim 1. The controller is
Slip detection means for detecting wheel slip of the electric vehicle;
A slip avoiding means for suppressing the torque command value during wheel idling of the electric vehicle,
The control device, when setting the torque command value by the torque command value increase restricting unit, detects a wheel idling of the electric vehicle by the idling detection unit, and causes the torque command value of the electric motor by the slip avoidance unit. The electric vehicle according to claim 1, wherein the vehicle is set to be lower than when the wheel idling occurs.

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