Electric vehicle control device

Abstract

To provide a control device of an electric vehicle which can suppress locking of a tire due to a regenerative torque even in such a state that a regenerative torque setting function does not normally function in an electric vehicle that performs regeneration in deceleration.SOLUTION: An ECU 31 of a hybrid system 10 (a control device of an electric vehicle) includes a target torque calculation unit 42 (regenerative torque setting unit) which sets a regenerative torque T instructed to a hybrid vehicle 1 to a limit torque Ta (limit value) smaller than that in the normal time in a case where the regenerative torque T is requested when an abnormality occurs in the hybrid vehicle 1 (vehicle).SELECTED DRAWING: Figure 2

Description

[Technical Field]

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

[0002] 2. Description of the Related Art In an electric vehicle in which drive wheels are driven by the rotational force of a drive motor, when the accelerator is closed, control is performed to decelerate the vehicle using regenerative torque generated in the drive motor.

[0003] For example, Patent Document 1 discloses that when an abnormality occurs in a vehicle behavior stabilization assist device, the state of regenerative braking control of the electric motor is maintained. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2014 / 013991 Summary of the Invention [Problem to be solved by the invention]

[0005] In the vehicle braking force generating device disclosed in Patent Document 1, if an abnormality occurs in the vehicle behavior stabilization support device, the regenerative braking control state of the electric motor is maintained. Therefore, if strong regeneration is occurring, this state is maintained, which has the problem that the vehicle tires may lock and the behavior may become unstable.

[0006] An object of the present invention is to provide a control device for an electric vehicle that performs regeneration during deceleration and that can suppress tire locking due to regenerative torque even when the regenerative torque setting function is not functioning normally. [Means for solving the problem]

[0007] In order to achieve the above object, the control device of the electric vehicle according to the present invention is a control device for an electric vehicle that performs regeneration during deceleration, and is configured to prevent a problem that occurs when generating regenerative torque in a drive motor of the vehicle. , VSC abnormality, or brake light abnormality The vehicle is provided with a regenerative torque setting unit that sets a target regenerative torque to be instructed to the vehicle to a limit value that is smaller than that under normal circumstances when regenerative torque is required upon occurrence of an abnormality.

[0008] According to this configuration, the regenerative torque is limited when the vehicle is in an abnormal state, thereby making it possible to prevent the tires from locking.

[0009] Furthermore, in the control device for an electric vehicle according to the present invention, if the target regenerative torque set at the control timing one cycle before is greater than the limit value, the regenerative torque setting unit gradually changes the target regenerative torque to the limit value when setting of the limit value is requested at the next control timing.

[0010] According to this configuration, the regenerative torque is gradually changed toward the limit value, thereby making it possible to prevent the behavior of the vehicle from becoming unstable.

[0011] Furthermore, in the control device for an electric vehicle according to the present invention, when the vehicle recovers from an abnormality, the regenerative torque setting unit gradually changes the regenerative torque from the limit value to the normal regenerative torque.

[0012] With this configuration, when the vehicle abnormality is resolved, the target regenerative torque can be generated in a normal state. Furthermore, since the regenerative torque is gradually changed toward the target regenerative torque, it is possible to prevent the vehicle's behavior from becoming unstable when the vehicle recovers from the abnormality.

[0013] In addition, in the control device for an electric vehicle according to the present invention, if the regenerative torque setting unit detects that the vehicle is slipping while the regenerative torque is limited to a limit value, it sets the limit value to an even smaller limit value.

[0014] This configuration can further reduce the amount of slip of the vehicle.

[0015] In the control device for an electric vehicle according to the present invention, the limit value is set so that the deceleration of the vehicle is such that the brake lights of the vehicle do not need to be turned on.

[0016] With this configuration, the driver of the following vehicle will not be panicked by the vehicle experiencing high deceleration without the brake lights being turned on. [Effects of the Invention]

[0017] According to the present invention, in an electric vehicle that performs regeneration during deceleration, when the regenerative torque setting function is not functioning normally, it is possible to prevent tires from locking due to regenerative torque. [Brief explanation of the drawings]

[0018] [Figure 1] FIG. 1 is a block diagram showing an example of the overall configuration of a control device for an electric vehicle. [Figure 2] FIG. 2 is a functional block diagram showing an example of the functional configuration of a control device for an electric vehicle. [Figure 3] FIG. 3 is a time chart showing an example of the operation of the control device for an electric vehicle. [Figure 4] FIG. 4 is a flowchart showing an example of the flow of processing performed by the control device of the electric vehicle. DETAILED DESCRIPTION OF THE INVENTION

[0019] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0020] (Embodiment) A control device for an electric vehicle according to an embodiment of the present invention will be described with reference to Fig. 1. Fig. 1 is a block diagram showing an example of the overall configuration of a control device for an electric vehicle.

[0021] (Overall configuration of the control device for electric vehicles) The hybrid vehicle 1 is equipped with a series hybrid system 10. The hybrid system 10 includes an engine 11, a generator motor (MG1) 12, a drive motor (MG2) 13, a battery 14, and a PCU (Power Control Unit) 15.

[0022] The engine 11 is, for example, a gasoline engine.

[0023] The generator motor 12 is, for example, a permanent magnet synchronous motor. The rotating shaft of the generator motor 12 is mechanically connected to the crankshaft of the engine 11 via a gear (not shown). For example, an output gear of the engine 11 is supported on the crankshaft of the engine 11 so as not to rotate relative to the crankshaft, and an output gear of the engine 11 is supported on the rotating shaft of the generator motor 12 so as not to rotate relative to the crankshaft, and the output gear of the engine 11 and the motor gear are meshed.

[0024] The drive motor 13 is, for example, a permanent magnet synchronous motor that is larger than the generator motor 12. A rotating shaft of the drive motor 13 is connected to a drive system 16 of the hybrid vehicle 1. The drive system 16 includes a differential gear, and the power of the drive motor 13 is transmitted to the differential gear and then distributed and transmitted from the differential gear to drive wheels 17 consisting of left and right front or rear wheels. This causes the left and right drive wheels 17 to rotate, causing the hybrid vehicle 1 to move forward or backward.

[0025] The battery 14 is a battery pack made up of a combination of a plurality of secondary batteries. The secondary batteries are, for example, lithium ion batteries. The battery 14 outputs, for example, DC power of approximately 200 to 350V.

[0026] The PCU 15 is a unit for controlling the driving of the generator motor 12 and the drive motor 13, and includes a first inverter 21, a second inverter 22, and a converter .

[0027] When starting the engine 11, the DC power output from the battery 14 is boosted by the converter 23, the boosted DC power is converted into AC power by the first inverter 21, and the AC power is supplied to the generator motor 12. This causes the generator motor 12 to perform power running, and the engine 11 is motored (cranked) by the generator motor 12. When the rotation speed of the crankshaft of the engine 11 has increased to the rotation speed required for starting due to motoring, the ignition plug of the engine 11 is sparked, and the engine 11 starts.

[0028] When the hybrid vehicle 1 is traveling, the drive motor 13 is operated in a power running mode, and the drive motor 13 generates power.

[0029] When the output required of the drive motor 13 is smaller than the output of the battery 14, the hybrid vehicle 1 runs in EV mode. That is, the engine 11 is stopped, power generation by the generator motor 12 is not performed, and power is supplied from the battery 14 to the drive motor 13, which is then driven by the power.

[0030] Furthermore, when the remaining capacity of the battery 14 falls below a predetermined level, the generator motor 12 operates to generate electricity while the engine 11 is running, regardless of whether the drive motor 13 is running or stopped. At this time, AC power from the generator motor 12 is converted to DC power by the first inverter 21, and the DC power output from the first inverter 21 is stepped down by the converter 23. The stepped-down DC power is supplied to the battery 14, thereby charging the battery 14.

[0031] When the hybrid vehicle 1 decelerates, the drive motor 13 undergoes regenerative operation, and power transmitted from the drive wheels 17 to the drive motor 13 is converted into AC power. At this time, the drive motor 13 acts as a resistance in the traveling drive system, and this resistance acts as a braking force (regenerative braking force) that brakes the hybrid vehicle 1. At this time, in the PCU 15, the AC power supplied from the drive motor 13 to the second inverter 22 is converted into DC power by the second inverter 22, and the DC power output from the second inverter 22 is stepped down by the converter 23. The stepped-down DC power is then supplied to the battery 14, thereby charging the battery 14.

[0032] The hybrid vehicle 1 is equipped with a plurality of ECUs (Electronic Control Units). Each ECU has a microcontroller unit (microcomputer), which incorporates, for example, a CPU, a nonvolatile memory such as a flash memory, and a volatile memory such as a dynamic random access memory (DRAM). The plurality of ECUs are connected to enable bidirectional communication using the CAN (Controller Area Network) communication protocol. Each ECU is connected to various sensors required for control, and receives detection signals from the connected sensors. In addition to the detection signals received from the various sensors, each ECU also receives information required for control from other ECUs.

[0033] 1 shows an ECU 31, one of the multiple ECUs, that controls the hybrid system 10. The ECU 31 is an example of a control device for an electric vehicle in the present disclosure. The ECU 31 is connected to an accelerator sensor 32, a vehicle speed sensor 33, and a wheel speed sensor 34. The accelerator sensor 32 outputs a detection signal corresponding to the amount of operation of an accelerator pedal operated by a driver (operator). The vehicle speed sensor 33 outputs, as a detection signal, a pulse signal synchronized with the rotation of a rotating body that rotates as the hybrid vehicle 1 travels. The wheel speed sensor 34 outputs, as a detection signal, a pulse signal synchronized with the rotation of each wheel (drive wheels 17 and non-drive wheels not shown) of the hybrid vehicle 1.

[0034] The ECU 31 calculates the accelerator opening, which is the ratio of the current operation amount to the maximum operation amount of the accelerator pedal, from the detection signal of the accelerator sensor 32. The ECU 31 also calculates the frequency of the detection signal (pulse signal) from the detection signal of the vehicle speed sensor 33 and converts the frequency into the vehicle speed of the hybrid vehicle 1. The ECU 31 also calculates the frequency of the detection signal (pulse signal) from the detection signal of the wheel speed sensor 34 and converts the frequency into the wheel speed of each wheel of the hybrid vehicle 1.

[0035] The ECU 31 sets the required power running torque or regenerative torque from the calculated accelerator opening and vehicle speed. Specifically, the ECU 31 stores in advance a table that outputs the power running torque or regenerative torque required when the accelerator opening and vehicle speed are input. The ECU 31 then sets the required power running torque or regenerative torque based on the table.

[0036] Furthermore, the ECU 31 issues a command to the PCU 15 to generate the set powering torque or regenerative torque. The PCU 15 then passes the command to the drive motor 13. When issuing a command to the PCU 15 to generate the required torque, the ECU 31 does not instantaneously switch the current torque to the target torque, but gradually changes the current torque toward the target torque. This prevents the stability of the hybrid vehicle 1 from being impaired by a sudden change in torque.

[0037] Furthermore, the ECU 31 detects whether or not slippage is occurring in the hybrid vehicle 1 from the wheel speed based on the output of the wheel speed sensor 34. If slippage is occurring in the hybrid vehicle 1, the ECU 31 limits the target value of the regenerative torque to be instructed to the PCU 15 so as to suppress the slippage.

[0038] Furthermore, when the ECU 31 issues a command to generate regenerative torque, if the deceleration occurring in the hybrid vehicle 1 exceeds a predetermined value, the ECU 31 turns on the brake lights 40. This notifies the driver of the following vehicle that the hybrid vehicle 1 will decelerate.

[0039] Furthermore, the ECU 31 detects the occurrence of an abnormality related to the hybrid system 10. The abnormality detected here is an abnormality that may prevent the ECU 31 from operating normally, such as a VSC abnormality, a brake light abnormality, or a communication abnormality.

[0040] The VSC abnormality is an abnormality related to the VSC (Vehicle Stability Control) system installed in the hybrid vehicle 1. The VSC is a device for preventing skidding of the vehicle. When turning on a slippery road, the VSC suppresses skidding of the vehicle and stabilizes the vehicle's posture. For example, if an accurate output from the wheel speed sensor 34 cannot be obtained, the hybrid vehicle 1 determines that an abnormality has occurred in the VSC. As a result, the ECU 31 is unable to correctly detect that the hybrid vehicle 1 has slipped.

[0041] An abnormality in the brake lights 40 may be, for example, a bulb blowing out if the brake lights 40 are of the incandescent type, or a malfunction in the lighting control circuit if the brake lights 40 are of the LED type. If an abnormality occurs in the brake lights 40, the brake lights 40 may not light up even if a large deceleration occurs in the hybrid vehicle 1 when a high regenerative torque is applied, which may cause the driver of the following vehicle to panic.

[0042] The communication abnormality is an abnormality in the in-vehicle network 50, which is an in-vehicle local area network (LAN) such as a control area network (CAN), that connects the components of the hybrid system 10. If an abnormality occurs in the in-vehicle network 50, the ECU 31 will be unable to exchange signals normally, which may cause a disruption to the control of the hybrid system 10.

[0043] These abnormalities may be resolved over time. For example, a disruption in CAN communication may be resolved at a certain timing. Also, the VSC abnormality may be resolved when the wheel speed sensor 34 regains an accurate output. For this reason, the ECU 31 continuously monitors the occurrence of an abnormality. If an abnormal state occurs, the ECU 31 controls the hybrid system 10 according to the abnormal state. Furthermore, if the ECU 31 recovers from the abnormal state, the ECU 31 controls the hybrid system 10 as in normal operation.

[0044] (Functional configuration of the control device for electric vehicles) Next, the functional configuration of the ECU 31 (control device for an electric vehicle) will be described with reference to Fig. 2. Fig. 2 is a functional block diagram showing an example of the functional configuration of the control device for an electric vehicle.

[0045] By executing a control program that operates the ECU 31, the ECU 31 realizes, as functional units, an abnormality detection unit 41, a target torque calculation unit 42, a slip detection unit 43, a gradual torque change control unit 44, an MG2 torque instruction unit 45, and a brake light illumination control unit 46 shown in FIG. 2.

[0046] The abnormality detection unit 41 detects whether a predetermined abnormality has occurred in the hybrid system 10. The predetermined abnormality is an abnormality that interferes with the generation of regenerative torque in the drive motor (MG2) 13, such as the above-mentioned VSC abnormality, an abnormality in the brake lights 40, or a communication abnormality.

[0047] The target torque calculation unit 42 calculates a target torque to be instructed to the drive motor (MG2) 13. The target torque calculation unit 42 calculates a powering torque or a regenerative torque according to the accelerator pedal position and the vehicle speed. In this embodiment, the target torque calculation unit 42 is described for the case where the driver closes the accelerator pedal, that is, the case where the hybrid vehicle 1 requests a regenerative torque T. The target torque calculation unit 42 is an example of a regenerative torque setting unit in the present disclosure.

[0048] In addition, when a regenerative torque T is required when an abnormality occurs in the hybrid vehicle 1, the target torque calculation unit 42 sets the regenerative torque to be instructed to the hybrid vehicle 1 to a limit torque Ta (limit value) that is smaller than normal.

[0049] Furthermore, when the regenerative torque T set at the control timing one cycle before is greater than the limit torque Ta, the target torque calculation unit 42 gradually changes the regenerative torque T to the limit torque Ta at the next control timing.

[0050] Furthermore, when the hybrid vehicle 1 recovers from an abnormality, the target torque calculation unit 42 gradually changes the regenerative torque T from the limit torque Ta to the target torque Tb for normal times.

[0051] Furthermore, if the target torque calculation unit 42 detects that the hybrid vehicle 1 is slipping while the regenerative torque T is limited to the limit torque Ta, it sets the limit torque Ta to an even smaller limit torque Tc.

[0052] The slip detection unit 43 detects whether or not a slip has occurred in the hybrid vehicle 1 based on the output of the wheel speed sensor .

[0053] The torque gradual change control unit 44 sets a time change in the target torque such that the current regenerative torque is gradually changed to the regenerative torque T set by the target torque calculation unit 42 .

[0054] The MG2 torque instruction unit 45 instructs the drive motor (MG2) 13 to generate a time-varying change in the target torque set by the gradual torque change control unit 44.

[0055] The brake light control unit 46 turns on the brake lights 40 when the deceleration a of the hybrid vehicle 1 generated by the regenerative torque T is greater than a predetermined value ap.

[0056] (An example of the operation of a control device for an electric vehicle) Next, an example of the operation performed by ECU 31 (control device for an electric vehicle) will be described with reference to Fig. 3. Fig. 3 is a time chart showing an example of the operation of the control device for an electric vehicle. The horizontal axis of Fig. 3 represents time t. Each graph in Fig. 3 shows the accelerator opening O, vehicle speed V, regenerative torque T, deceleration a, and state of brake lights 40 at time t. Note that Fig. 3 simply depicts the main points of time changes in each quantity, and some parts may differ from the actual time changes.

[0057] Below, we will explain an example of the operation performed by the ECU 31 when the hybrid vehicle 1 is in a normal state and no abnormality has occurred, an example of the operation performed by the ECU 31 when an abnormality has occurred in the hybrid vehicle 1, and an example of the operation performed by the ECU 31 when slippage occurs in the hybrid vehicle 1 when an abnormality has occurred in the hybrid vehicle 1.

[0058] (Example of normal operation) First, an example of the operation performed by the ECU 31 under normal conditions will be described. Assume that the driver of the hybrid vehicle 1 releases the accelerator pedal at time ta. That is, the accelerator opening degree 0 of the hybrid vehicle 1 is fully closed at time ta.

[0059] It is assumed that the hybrid vehicle 1 has been traveling at a vehicle speed Va until time ta. At time ta, the accelerator opening degree O becomes fully closed, and therefore, after time ta, the vehicle speed V of the hybrid vehicle 1 decreases from the vehicle speed Va. Note that the vehicle speed V may be considered as the rotation speed of the drive motor (MG2) 13.

[0060] The target torque calculation unit 42 of the hybrid vehicle 1 sets a target torque Tb to be generated by the drive motor (MG2) 13 in accordance with the vehicle speed V and the accelerator opening O. Then, the torque gradual change control unit 44 sets a time characteristic for gradually changing the regenerative torque T to the target torque Tb between time ta and time tc. Then, the MG2 torque instruction unit 45 instructs the drive motor (MG2) 13 to execute a time change specification of the set regenerative torque T. In this way, the ECU 31 realizes the time change of the regenerative torque T shown by the dotted line in FIG. 3. The degree of gradual change of the regenerative torque T (the time change rate of the regenerative torque T when gradually changing) is set by, for example, compatibility evaluation using an actual vehicle.

[0061] As a result of the instructed regenerative torque T acting, the hybrid vehicle 1 generates a deceleration a shown in FIG. 3 from time ta onwards.

[0062] When the deceleration a of the hybrid vehicle 1 reaches a predetermined value ap at time tc, the brake lights 40 are turned on, thereby informing the following vehicles that the hybrid vehicle 1 is decelerating.

[0063] Thereafter, when the deceleration a of the hybrid vehicle 1 decreases and falls below the predetermined value ap at time td, the brake lights 40 are turned off.

[0064] (Example of abnormal behavior) Next, an example of the operation performed by the ECU 31 in the event of an abnormality will be described. Assume that the driver of the hybrid vehicle 1 releases the accelerator at time ta. That is, the accelerator opening degree 0 of the hybrid vehicle 1 is fully closed at time ta.

[0065] It is assumed that the hybrid vehicle 1 has been traveling at a vehicle speed Va until time ta. At time ta, the accelerator opening degree O becomes fully closed, and therefore, after time ta, the vehicle speed V of the hybrid vehicle 1 decreases from the vehicle speed Va. Note that the vehicle speed V may be considered as the rotation speed of the drive motor (MG2) 13.

[0066] The target torque calculation unit 42 of the hybrid vehicle 1 sets the regenerative torque T to be generated by the drive motor (MG2) 13 in accordance with the vehicle speed V and the accelerator opening O. At this time, because an abnormality has occurred in the hybrid vehicle 1, the target torque calculation unit 42 limits the target torque to a limit torque Ta that is smaller than the target torque Tb in a normal state. The torque gradual change control unit 44 then sets a time characteristic for gradually changing the regenerative torque T to the limit torque Ta between time ta and time tb. The MG2 torque command unit 45 then commands the drive motor (MG2) 13 to execute a time change specification of the set regenerative torque T. As a result, the ECU 31 realizes the time change of the regenerative torque T shown by the solid line in FIG. 3. The degree of gradual change of the regenerative torque T (the time change rate of the regenerative torque T when gradually changing) is set by, for example, compatibility evaluation using an actual vehicle.

[0067] As a result of the instructed regenerative torque T acting, the hybrid vehicle 1 generates a deceleration a shown in FIG. 3 from time ta onwards.

[0068] The deceleration a of the hybrid vehicle 1 reaches the deceleration aq at time tb when the regenerative torque T reaches the limit torque Ta. Since the deceleration aq is smaller than the predetermined value ap described above, it is not necessary to turn on the brake lights 40.

[0069] (An example of how a slip occurs during an abnormal situation) Next, an example of the operation performed by the ECU 31 when slippage occurs in the hybrid vehicle 1 during an abnormality will be described.

[0070] It is assumed that the driver of the hybrid vehicle 1 releases the accelerator at time ta. That is, the accelerator opening degree O of the hybrid vehicle 1 is in a fully closed state at time ta.

[0071] It is assumed that the hybrid vehicle 1 has been traveling at a vehicle speed Va until time ta. At time ta, the accelerator opening degree O becomes fully closed, and therefore, after time ta, the vehicle speed V of the hybrid vehicle 1 decreases from the vehicle speed Va. Note that the vehicle speed V may be considered as the rotation speed of the drive motor (MG2) 13. It is also assumed that, at time td, the hybrid vehicle 1 begins to slip. At this time, the tire loses grip due to the slip, and therefore, the rate of decrease of the vehicle speed V increases at time td (the dashed-dotted line of the vehicle speed V in FIG. 3).

[0072] The target torque calculation unit 42 of the hybrid vehicle 1 sets the regenerative torque T to be generated by the drive motor (MG2) 13 in accordance with the vehicle speed V and the accelerator opening O. At this time, because an abnormality has occurred in the hybrid vehicle 1, the target torque calculation unit 42 limits the target torque to a limit torque Ta that is smaller than the target torque Tb in a normal state. Then, the torque gradual change control unit 44 sets a time characteristic that gradually changes the regenerative torque T to the limit torque Ta between time ta and time tb. Then, the MG2 torque command unit 45 commands the drive motor (MG2) 13 to execute a time change specification of the set regenerative torque T. As a result, the ECU 31 realizes the time change of the regenerative torque T shown by the solid line in FIG. 3.

[0073] Then, at time td, when slippage is detected in the hybrid vehicle 1, the target torque calculation unit 42 reduces the limit torque Ta (limit value) of the regenerative torque T to an even smaller limit torque Tc (limit value). The torque gradual change control unit 44 then sets a time characteristic for gradually changing the regenerative torque T from the limit torque Ta at time td to the limit torque Tc at time te. The MG2 torque command unit 45 then commands the drive motor (MG2) 13 to execute the set time change specification of the regenerative torque T. As a result, the ECU 31 realizes the time change of the regenerative torque T shown by the dashed dotted line in FIG. 3.

[0074] As a result of the instructed regenerative torque T acting, the hybrid vehicle 1 generates a deceleration a shown in FIG. 3 from time ta onwards.

[0075] The deceleration a of the hybrid vehicle 1 reaches the deceleration ar at time te when the regenerative torque T reaches the limit torque Tc. In the event of an abnormality, the deceleration ar is smaller than the deceleration aq that occurs when the hybrid vehicle 1 is not slipping, so slipping of the hybrid vehicle 1 is suppressed.

[0076] Moreover, since the deceleration ar occurring at this time is smaller than the predetermined value ap, the brake lights 40 do not light up.

[0077] (Flow of processing performed by the control device of an electric vehicle) Next, the flow of processing performed by the ECU 31 (control device for an electric vehicle) will be described with reference to Fig. 4. Fig. 4 is a flowchart showing an example of the flow of processing performed by the control device for an electric vehicle.

[0078] The target torque calculation unit 42 calculates a target torque to be instructed to the drive motor (MG2) 13 (step S11).

[0079] The abnormality detection unit 41 determines whether a VSC abnormality, an abnormality in the brake lights 40, or a communication abnormality has occurred in the hybrid vehicle 1 (step S12). If it is determined that a corresponding abnormality has occurred (step S12: Yes), the process proceeds to step S13. On the other hand, if it is not determined that a corresponding abnormality has occurred (step S12: No), the process proceeds to step S17.

[0080] If it is determined in step S12 that a corresponding abnormality has occurred, the target torque calculation unit 42 determines whether the regenerative torque T is necessary (step S13). If it is determined that the regenerative torque T is necessary (step S13: Yes), the process proceeds to step S14. On the other hand, if it is determined that the regenerative torque T is not necessary (step S13: No), the process proceeds to step S20.

[0081] If it is determined in step S13 that regenerative torque T is required, the target torque calculation unit 42 determines whether the target torque one cycle before is smaller than the limit torque Ta (limit value) (step S14). If it is determined that the target torque one cycle before is smaller than the limit torque Ta (step S14: Yes), the process proceeds to step S15. On the other hand, if it is not determined that the target torque one cycle before is smaller than the limit torque Ta (step S14: No), the process proceeds to step S16.

[0082] If it is determined in step S14 that the target torque one cycle before is smaller than the limit torque Ta, the gradual torque change control unit 44 sets a time change for gradually changing the regenerative torque T to the target torque set in step S11 (step S15), and then proceeds to step S20.

[0083] On the other hand, if it is determined in step S14 that the target torque one cycle before is not smaller than the limit torque Ta, the torque gradual change control unit 44 sets a time change for gradually changing the regenerative torque T to the limit torque Ta (limit value) (step S16), and then proceeds to step S20.

[0084] Returning to step S12, if it is determined in step S12 that the relevant abnormality has not occurred, the target torque calculation unit 42 determines whether the regenerative torque T is necessary (step S17). If it is determined that the regenerative torque T is necessary (step S17: Yes), the process proceeds to step S18. On the other hand, if it is not determined that the regenerative torque T is necessary (step S17: No), the process proceeds to step S20.

[0085] If it is determined in step S17 that regenerative torque T is necessary, target torque calculation unit 42 determines whether the target torque one cycle ago is greater than the target torque set in step S11 (step S18). If it is determined that the target torque one cycle ago is greater than the target torque set in step S11 (step S18: Yes), the process proceeds to step S19. On the other hand, if it is not determined that the target torque one cycle ago is greater than the target torque set in step S11 (step S18: No), the process proceeds to step S20.

[0086] If it is determined in step S18 that the target torque one cycle before is greater than the target torque set in step S11, the torque gradual change control unit 44 sets a time change for gradually changing the regenerative torque T to the target torque (step S19), and then proceeds to step S20.

[0087] After steps S15, S16, and S19 are performed, or if it is determined in steps S13 and S17 that regenerative torque T is not required, slip detection unit 43 determines whether slip has occurred in hybrid vehicle 1 (step S20). If it is determined that slip has occurred in hybrid vehicle 1 (step S20: Yes), the process proceeds to step S21. On the other hand, if it is not determined that slip has occurred in hybrid vehicle 1 (step S20: No), the process proceeds to step S22.

[0088] If it is determined in step S20 that slip has occurred in the hybrid vehicle 1, the target torque calculation unit 42 sets (limits) the target torque to a limit torque that is smaller than the limit torque Ta (limit value) (step S21).

[0089] Next, the torque gradual change control unit 44 sets the time change of the regenerative torque T to either the time change set in steps S15, S16, or S19, or the time change that gradually changes the torque up to the limit torque set in step S21 (step S22).

[0090] The MG2 torque instruction unit 45 instructs the drive motor (MG2) 13 to generate a time-varying target torque set by the gradual torque change control unit 44 (step S23).

[0091] The brake light illumination control unit 46 determines whether the deceleration a of the hybrid vehicle 1 is greater than a predetermined value ap (step S24). If it is determined that the deceleration a of the hybrid vehicle 1 is greater than the predetermined value ap (step S24: Yes), the process proceeds to step S25. On the other hand, if it is not determined that the deceleration a of the hybrid vehicle 1 is greater than the predetermined value ap (step S24: No), the process proceeds to step S26.

[0092] If it is determined in step S24 that the deceleration a of the hybrid vehicle 1 is greater than the predetermined value ap, the brake light lighting control unit 46 turns on the brake lights 40 (step S25), and then the process proceeds to step S27.

[0093] On the other hand, if it is determined in step S24 that the deceleration a of the hybrid vehicle 1 is not greater than the predetermined value ap, the brake light lighting control unit 46 turns off (does not light) the brake lights 40 (step S26). Then, the process proceeds to step S27.

[0094] Following steps S25 and S26, the ECU 31 determines whether the ignition (IGN) switch of the hybrid vehicle 1 is OFF (step S27). If it is determined that the ignition switch of the hybrid vehicle 1 is OFF (step S27: Yes), the ECU 31 ends the processing in Fig. 4. On the other hand, if it is not determined that the ignition switch of the hybrid vehicle 1 is OFF (step S27: No), the processing returns to step S11 and the above-described processing is repeated.

[0095] (Effects of the embodiment) As described above, the ECU 31 (control device for an electric vehicle) of the hybrid system 10 according to this embodiment has a function of performing regeneration during deceleration, and includes a target torque calculation unit 42 (regenerative torque setting unit) that sets the regenerative torque T to be instructed to the hybrid vehicle 1 to a limit torque Ta (limit value) that is smaller than the target torque Tb under normal conditions when a malfunction occurs in the hybrid vehicle 1 and a regenerative torque T is required. Therefore, since the regenerative torque T is limited when the hybrid vehicle 1 malfunctions, tire locking can be suppressed.

[0096] Furthermore, in the ECU 31 (control device for an electric vehicle) of the hybrid system 10 according to this embodiment, if the target torque Tb set at the control timing one cycle before is greater than the limit torque Ta, the target torque calculation unit 42 (regenerative torque setting unit) gradually changes the target torque Tb to the limit torque Ta (limit value) at the next control timing. Therefore, the regenerative torque T is gradually changed toward the limit torque Ta, which can prevent the behavior of the hybrid vehicle 1 from becoming unstable.

[0097] Furthermore, in the ECU 31 (control device for an electric vehicle) of the hybrid system 10 according to this embodiment, when the hybrid vehicle 1 (vehicle) recovers from an abnormality, the target torque calculation unit 42 (regenerative torque setting unit) gradually changes the regenerative torque T from the limit torque Ta (limit value) to the target torque Tb in normal operation. Therefore, when the abnormality of the hybrid vehicle 1 is resolved, the target regenerative torque in normal operation can be generated. Furthermore, because the regenerative torque T is gradually changed toward the target regenerative torque, it is possible to prevent the behavior of the hybrid vehicle 1 from becoming unstable when the hybrid vehicle 1 recovers from an abnormality.

[0098] Furthermore, in the ECU 31 (control device for an electric vehicle) of the hybrid system 10 according to this embodiment, if the target torque calculation unit 42 (regenerative torque setting unit) detects that the hybrid vehicle 1 (vehicle) is slipping while the regenerative torque T is limited to the limit torque Ta (limit value), it sets the limit torque Ta to an even smaller limit torque Tc. Therefore, the amount of slip of the hybrid vehicle 1 can be further reduced.

[0099] Furthermore, in the ECU 31 (control device for an electric vehicle) of the hybrid system 10 according to this embodiment, the limit torque Ta (limit value) is set so that the deceleration a of the hybrid vehicle 1 (vehicle) is a deceleration that does not require the brake lights 40 of the hybrid vehicle 1 to be turned on. Therefore, the driver of the following vehicle will not be alarmed by the hybrid vehicle 1 experiencing high deceleration when the brake lights 40 are not turned on.

[0100] Although the embodiments of the present invention have been described above, the above-described embodiments are presented as examples and are not intended to limit the scope of the present invention. This novel embodiment can be embodied in various other forms. Furthermore, various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. Furthermore, this embodiment is included within the scope and spirit of the invention, and is also included in the inventions and their equivalents as defined in the claims. [Explanation of symbols]

[0101] 1 Hybrid vehicle 10 Hybrid System 11 Engine 12 Generator motor (MG1) 13 Drive motor (MG2) 14 Battery 15 PCU 16 Drivetrain 17 Drive wheels 21 First inverter 22 Second inverter 23 Converter 31 ECU (Electric vehicle control unit) 32 Accelerator sensor 33 Vehicle speed sensor 34 Wheel speed sensor 40 Brake lights 41 Abnormality detection unit 42 Target torque calculation unit (regenerative torque setting unit) 43 Slip detection unit 44 Gradual torque change control section 45 MG2 torque indicator 46 Brake light control unit 50 In-vehicle network O Accelerator opening T Regenerative torque Ta, Tc limit torque (limit value) Tb Target torque V,Va Vehicle speed a Deceleration ap predetermined value t,ta,tb,tc,td,te time

Claims

1. A control device for an electric vehicle that performs regeneration during deceleration, The vehicle is provided with a regenerative torque setting unit that sets the regenerative torque to be instructed to the vehicle to a limit value that is smaller than the target regenerative torque under normal circumstances when regenerative torque is required in response to the occurrence of either a VSC abnormality or a brake light abnormality that interferes with the generation of regenerative torque in the drive motor. Control device for electric vehicles.

2. the regenerative torque setting unit gradually changes the target regenerative torque to the limit value at the next control timing when the target regenerative torque set at the control timing one cycle before is greater than the limit value; The control device for an electric vehicle according to claim 1.

3. When the vehicle recovers from the abnormality, The regenerative torque setting unit gradually changes the regenerative torque from the limit value to a target regenerative torque in normal operation. The control device for an electric vehicle according to claim 1 or 2.

4. The regenerative torque setting unit When it is detected that the vehicle has slipped while the regenerative torque is limited to the limit value, the limit value is set to a smaller limit value. The control device for an electric vehicle according to any one of claims 1 to 3.

5. The limit value is set so that the deceleration of the vehicle does not require the brake lights of the vehicle to be turned on. The control device for an electric vehicle according to any one of claims 1 to 4.

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