JP2022163627A - electric vehicle - Google Patents

Abstract

To output torque required for running even when resuming running by two-phase driving from a vehicle stop state after retreat running.SOLUTION: An electric vehicle comprises: a three-phase electric motor; an inverter that has a plurality of switching elements and drives the three-phase electric motor; a control device that controls the three-phase electric motor; and a rotor angle sensor that detects a rotor angle of the three-phase electric motor and outputs the detected value to the control device. The control device, when detecting an abnormality in one phase of any of the plurality of switching elements during running, executes retreat-running control by which the electric vehicle is stopped so that the rotor angle of the three-phase electric motor during stop of the vehicle is equal to a target rotor angle at which torque of a predetermined value or more can be output when the electric motor is driven in remaining two-phases.SELECTED DRAWING: Figure 3

Description

The present invention relates to electric vehicles.

In Patent Document 1, in an electric vehicle that runs on power output from a three-phase motor, if one phase of an inverter element fails during running, the remaining two phases drive the three-phase motor to perform evacuation running. is disclosed.

WO 13/008313

In the configuration described in Patent Literature 1, when the vehicle is to be restarted after being stopped for evacuation, the remaining two phases drive the three-phase motor. However, in the configuration described in Patent Literature 1, the electric vehicle is stopped by inertia when the vehicle is evacuated, so the position at which the rotor angle of the three-phase electric motor stops is determined by inertia. Therefore, depending on the rotor angle of the three-phase motor when the vehicle is stopped, there is a possibility that the torque necessary for running cannot be output when the vehicle is restarted from a stopped state by two-phase drive.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and is an electric vehicle capable of outputting the torque necessary for running even when the vehicle resumes running by two-phase drive from a stopped state after evacuation running. The purpose is to provide a vehicle.

The present invention provides a three-phase motor as a power source for running, an inverter having a plurality of switching elements and driving the three-phase motor, a control device for controlling the three-phase motor, and a control device for controlling the three-phase motor. and a rotor angle sensor that detects a rotor angle and outputs the detected value to the control device, wherein the control device controls any one of the plurality of switching elements during running. When the abnormality is detected, the electric vehicle is stopped so that the rotor angle of the three-phase electric motor when stopped becomes a target rotor angle that can output a torque of a predetermined value or more when driven by the remaining two phases. It is characterized by executing evacuation control.

According to this configuration, when the vehicle resumes traveling from a stopped state after the evacuation traveling, it is possible to output torque necessary for traveling from the three-phase motor even if the remaining two-phase drive is used. Therefore, it is possible to suppress the driving force shortage when restarting the vehicle.

Further, the limp-run control turns on the three-phase switching elements of the upper arm of the inverter, or turns on the three-phase switching elements of the lower arm to decelerate the electric vehicle by inertia. Calculation control for calculating the difference between the current rotor angle and the target rotor angle during execution of the inertia running control; Controlling the torque of the three-phase electric motor based on the difference; and torque control to stop the angle at the target rotor angle.

According to this configuration, the difference between the current rotor angle and the target rotor angle is calculated during coasting by executing the limp-home run control, and the rotor angle is stopped at the target stop position according to the difference. can control the torque of a three-phase motor.

In the inertial running control, the control device controls to turn on the three-phase switching elements of the upper arm and the lower arm that include the switching element that detected the abnormality. good too.

According to this configuration, the electric vehicle can be coasted by turning ON all phase elements on the arm side including the switching element in which the abnormality is detected.

In the calculation control, the control device calculates the distance from the current rotor angle to the target rotor angle, and in the torque control, calculates the torque of the three-phase electric motor based on the distance to the target rotor angle. Even if the calculated distance to the target rotor angle is a value obtained by multiplying the angular difference from the current rotor angle to the target rotor angle by the number of revolutions of the three-phase motor and 360, good.

According to this configuration, the torque of the three-phase electric motor can be controlled so that the rotor angle stops at the target stop position based on the distance from the current rotor angle to the target rotor angle during coasting.

Further, the torque control uses the torque calculated based on the distance to the target rotor angle as the command torque, and uses the difference between the command torque and the actual torque actually output from the three-phase motor as the command torque. A summing correction control may be included.

According to this configuration, the command torque can be corrected based on the difference between the command torque and the actual torque actually output from the three-phase motor in the remaining two-phase drive during inertia running.

Further, the control device may change the distance to the target rotor angle when detecting a brake pedal depression operation during execution of the evacuation control.

According to this configuration, when a brake operation is detected during coasting, the electric vehicle stops before the initially planned position, so the distance to the target rotor angle can be changed.

Further, a fuse is provided in a path that electrically connects the three-phase electric motor and the inverter, and the control device detects an abnormality when the electric vehicle is stopped after executing the evacuation control. Blowing control may be performed to blow the fuse corresponding to the detected one phase.

According to this configuration, the fuse corresponding to the phase in which the abnormality has been detected can be blown by executing the fuse blowing control when the vehicle is stopped after the evacuation run. As a result, it is possible to prevent current from flowing through the faulty phase when the vehicle resumes running thereafter, thereby improving the safety against energization.

Further, when the electric vehicle resumes running after executing the fusing control, the control device may execute running control for driving the three-phase electric motor with the remaining two phases.

According to this configuration, torque can be output from the three-phase motor by driving the remaining two phases while the fuse corresponding to the phase in which the abnormality has been detected is blown.

In the present invention, when the vehicle resumes traveling from a stopped state after the evacuation traveling, it is possible to output the torque required for traveling from the three-phase motor even if the remaining two-phase drive is used. Therefore, it is possible to suppress the driving force shortage when restarting the vehicle.

FIG. 1 is a diagram showing a case where a switching element of one phase of an inverter fails while an electric vehicle according to an embodiment is running. FIG. 2 is a diagram schematically showing a drive system mounted on an electric vehicle. FIG. 3 is a flow chart diagram showing a vehicle control flow. FIG. 4 is a diagram for explaining a state during evacuation control. FIG. 5 is a diagram for explaining the rotor angle. FIG. 6 is a diagram for explaining a method of calculating motor torque. FIG. 7 is a diagram for explaining the state during the fuse blowing control when the vehicle is stopped after the evacuation run. FIG. 8 is a diagram for explaining the state when the vehicle is restarted after stopping for evacuation. FIG. 9 is a flow chart diagram showing a vehicle control flow in the first modified example. FIG. 10 is a diagram for explaining a method of calculating motor torque in the first modified example. FIG. 11 is a flow chart diagram showing a vehicle control flow in the second modified example. FIG. 12 is a diagram for explaining a method of calculating motor torque in the second modified example.

An electric vehicle according to an embodiment of the present invention will be specifically described below with reference to the drawings. In addition, this invention is not limited to embodiment described below.

FIG. 1 is a diagram showing a case where a switching element of one phase of an inverter fails while an electric vehicle according to an embodiment is running. FIG. 2 is a diagram schematically showing a drive system mounted on an electric vehicle.

As shown in FIGS. 1 and 2, a vehicle 1 is an electric vehicle equipped with a motor 2 as a power source for running. The vehicle 1 is a front-wheel drive vehicle in which a front left wheel and a front right wheel are driven by power output from a motor 2, for example. The motor 2 is connected to the left and right driving wheels through a power transmission device such as a transmission and a differential gear mechanism so as to be able to transmit power. The vehicle 1 has a drive system 10 for controlling the torque required for running.

As shown in FIG. 2, the drive system 10 includes a motor 2, an inverter 3, a battery 4, and a controller 5.

In drive system 10 , DC power output from battery 4 is converted into AC power by inverter 3 , and motor 2 is driven by supplying this AC power from inverter 3 to motor 2 . At that time, the drive of the motor 2 is controlled by the command signal output from the control section 5 to the inverter 3 . The control section 5 controls the inverter 3 and the motor 2 . A smoothing capacitor C is provided in the drive system 10 . Moreover, the control device of the vehicle 1 includes at least the control unit 5 .

Motor 2 is electrically connected to battery 4 via inverter 3 and is driven by power supplied from battery 4 . The motor 2 and the inverter 3 are electrically connected via three-phase coils (U-phase, V-phase, W-phase). The motor 2 is driven by current flowing through the coils of each phase, and torque is output from the motor 2 . The motor 2 is a three-phase motor and a motor generator (MG) capable of functioning as an electric motor and a generator.

The inverter 3 is a power conversion device that drives the motor 2 . The inverter 3 is composed of an inverter circuit having six switching elements T1 to T6 so that a three-phase current can flow through the coils of the motor 2. FIG. The inverter circuit includes a switching element and a diode for each phase, and converts DC power into AC power by switching operation of the switching element. A switching operation is an operation in which ON and OFF of a switching element are switched. Each switching element T1 to T6 is composed of, for example, an insulated gate bipolar transistor. As shown in FIG. 2, this inverter 3 has upper and lower arms 11, 12 and 13 for each phase (U phase, V phase and W phase). element and two diodes.

The U-phase upper and lower arm 11 has an upper arm 11a in which a switching element T1 and a diode D1 are connected in parallel, and a lower arm 11b in which a switching element T2 and a diode D2 are connected in parallel. and the lower arm 11b are connected in series. The V-phase upper and lower arm 12 has an upper arm 12a in which a switching element T3 and a diode D3 are connected in parallel, and a lower arm 12b in which a switching element T4 and a diode D4 are connected in parallel. and the lower arm 12b are connected in series. The W-phase upper and lower arm 13 has an upper arm 13a in which a switching element T5 and a diode D5 are connected in parallel, and a lower arm 13b in which a switching element T6 and a diode D6 are connected in parallel. and the lower arm 13b are connected in series.

Further, in the drive system 10 , a fuse 6 is provided in a path that electrically connects the inverter 3 and the motor 2 . A fuse 6 is arranged on a path corresponding to each phase coil, and is fused when a current of a predetermined magnitude or more flows. The fuse 6 includes a first fuse 6a corresponding to the U phase, a second fuse 6b corresponding to the V phase, and a third fuse 6c corresponding to the W phase.

The first fuse 6 a is arranged between the connection point between the U-phase upper arm 11 a and the U-phase lower arm 11 b and the U-phase coil of the motor 2 . When the U-phase current exceeds a predetermined value, the first fuse 6a is blown. The second fuse 6 b is arranged between the connection point between the V-phase upper arm 12 a and the V-phase lower arm 12 b and the V-phase coil of the motor 2 . When the V-phase current exceeds a predetermined value, the second fuse 6b is blown. The third fuse 6 c is arranged between the connection point between the W-phase upper arm 13 a and the W-phase lower arm 13 b and the W-phase coil of the motor 2 . When the W-phase current exceeds a predetermined value, the third fuse 6c is blown.

The control unit 5 is configured by an electronic control unit (ECU) that drives and controls the motor 2 . The control unit 5 includes a microcomputer having a CPU, RAM, ROM, input/output interface, and the like. Signals from various sensors are input to the control unit 5 . The vehicle 1 is equipped with a rotor angle sensor 7 that detects the rotor angle of the motor 2 . A signal is input from the rotor angle sensor 7 to the controller 5 . The control unit 5 performs arithmetic processing for motor control, such as calculating the rotation speed of the motor 2 (hereinafter referred to as motor rotation speed) based on the input signal.

Then, as a result of the calculation, a command signal for controlling the inverter 3 is output from the controller 5 to the inverter 3 . The command signal to the inverter 3 includes a signal for switching the switching element whose switching operation is to be controlled among the plurality of switching elements T1 to T6. Thus, the controller 5 controls the voltage and current applied to the motor 2 by controlling the inverter 3 .

Further, as shown in FIG. 1, the control unit 5 executes evacuation running control when a failure (for example, a short-circuit failure) occurs in any one phase switching element of the inverter 3 during running. The evacuation control is a control that is executed as a fail-safe against an element failure in the inverter 3, and is a control for safely stopping the vehicle 1 that is running. Therefore, the vehicle 1 is provided with an element failure detector (ON failure detector) for detecting ON failures in the switching elements T1 to T6 of the inverter 3 . In other words, the drive system 10 is provided with an element failure detector that detects an ON failure of the switching elements T1 to T6 of the inverter 3 . When an abnormality occurs in the inverter 3 , a detection signal is output from the element failure detector, and the signal is input to the control section 5 . Thus, the control unit 5 can determine whether or not an element failure has occurred in the inverter 3 based on the detection signal from the element failure detector. FIG. 3 shows an example of vehicle control executed by the control unit 5. As shown in FIG.

FIG. 3 is a flow chart diagram showing a vehicle control flow. Note that the control shown in FIG. 3 is repeatedly executed by the control unit 5 while the vehicle 1 is running.

The control unit 5 determines whether or not an ON failure has occurred in any one-phase switching element of the inverter 3 during running (step S101). In step S101, it is determined whether or not an ON failure has occurred in any one phase of the switching elements T1 to T6 of the inverter 3. FIG. That is, it is determined whether or not an abnormality has occurred in any one of the six switching elements T1 to T6. Based on the detection signal from the element failure detector, the control unit 5 can determine whether or not there is an ON failure in the switching element.

If the switching elements T1 to T6 of the inverter 3 are not ON-failed during running (step S101: No), this control routine ends.

When an ON failure occurs in any one phase switching element of the inverter 3 during running (step S101: Yes), the control unit 5 turns on all the phase switching elements in the upper arm of the inverter 3 (step S102). In step S102, the control unit 5 starts evacuation control.

In step S102, the emergency running control is started, and as shown in FIG. 4, the switching elements of all phases are controlled to be ON for the arm including the failed switching element among the upper and lower arms. . In this case, the failed switching element is identified before all the phases of the upper arm switching elements are turned ON in step S102. That is, when detecting an abnormality in the inverter 3, the control unit 5 determines whether the arm of the failed switching element (hereinafter sometimes referred to as the failed arm) is the upper arm or the lower arm, and It is determined which of the U phase, V phase, and W phase the phase of the element (hereinafter sometimes referred to as the faulty phase) is. Through this discrimination process, it is possible to specify which element is the failed element among the six switching elements T1 to T6. This specific process (determination process) is performed, for example, in the determination process of step S101, after affirmative determination is made in step S101, or in the process of step S102. Then, in step S102, the switching elements of all phases are controlled to be ON for the faulty arm. That is, the element is controlled to be ON in the phase other than the faulty phase in the faulty arm. In this way, the control unit 5 starts the evacuation control in step S102, and controls the switching elements of the upper arm to turn ON all the phases, thereby decelerating the vehicle 1 by inertia. The evacuation control includes control for decelerating the vehicle 1 by inertia (hereinafter referred to as inertia control). Therefore, in step S102, inertial driving control is performed and the vehicle 1 will be coasting.

In this control flow, a case where the faulty element is the switching element T1 will be described as an example. That is, when it is determined that an ON failure has occurred in any one-phase switching element of the inverter 3, the U-phase upper arm element is identified as the faulty element. Therefore, the control unit 5 turns on the switching elements of all the phases of the upper arm including the faulty element.

Further, the control unit 5 calculates the distance to the target rotor angle during inertia running (step S103). The target rotor angle is a target stop position of the rotor angle when the vehicle 1 stops. The control unit 5 executes evacuation control during travel to safely stop the vehicle 1, and in consideration of the fact that the vehicle 1 travels again after stopping, controls the rotor angle so that the rotor angle at the time of stopping becomes the target rotor angle. to control the motor torque. That is, the control unit 5 executes, as the evacuation control, inertia control for turning on all phase elements of the upper arm, and stop position control for controlling the stop position of the rotor angle by controlling the torque of the motor 2. do. That is, the evacuation control includes stop position control. Then, when the vehicle resumes running from a stopped state after the evacuation running, the motor 2 is driven by the remaining two phases that are not out of order. Therefore, when the motor 2 is driven by the remaining two phases, the target rotor angle is set such that a torque of a predetermined value or more can be output. In this case, the target rotor angle can be set according to the failed phase. For example, when a U-phase switching element has an ON failure, the angle range of the target rotor angle that can be set is determined. can be set from This target rotor angle can be set by selecting a predetermined value from within a certain angle range, for example, a range of about 20°. Also, within the range of 0 to 360 for one rotation of the rotor, there are a plurality of candidate ranges that can be set for the target rotor angle. Then, in step S103, stop position control is started, the current rotor angle is specified based on the signal from the rotor angle detection sensor, and the distance from the current rotor angle to the target rotor angle is calculated.

A method of calculating the distance to the target rotor angle will be described with reference to FIG. In FIG. 5, the target rotor angle is described as the target value, and the current rotor angle is described as the current value. As shown in FIG. 5, the control unit 5 calculates the difference (angular difference) between the current rotor angle and the target rotor angle as the angular difference within the range of 0 to 360 degrees. Then, the control unit 5 calculates the distance to the target rotor angle based on this difference and the motor rotation speed. Specifically, it can be obtained by the formula "distance to target rotor angle=(angular difference between target value and current value)+360×N". N is the number of motor revolutions. Thus, the distance to the target rotor angle is obtained by adding the angular difference from the current rotor angle to the target rotor angle in the range of 0 to 360, the motor rotation speed, and 360. value. In step S103, the distance to the target rotor angle at the start of the evacuation control is calculated. That is, in step S103, stop position control for stopping the rotor angle at the target stop position is started, and the distance to the target rotor angle is calculated. The stop position control includes calculation control for calculating the difference between the current rotor angle and the target rotor angle, and calculation control for calculating the distance to the target rotor angle.

The control unit 5 also calculates the amount of movement of the rotor angle (step S104). In step S104, the amount of movement of the rotor angle after the evacuation control is started is calculated. As shown in FIG. 6, the control unit 5 sets the distance to the target rotor angle at the start of the evacuation control (time t1), and then calculates the movement amount A of the rotor angle after that (time t2). At this time, the amount of movement of the rotor angle at time t1 is zero, and the distance to the target rotor angle calculated at time t1 is set as the target value. By calculating the movement amount A of the rotor angle at time t2, the control unit 5 determines the distance to the target rotor angle (the target value calculated at time t1) and the movement amount A (the value calculated at time t2). ) can be calculated. This difference B can be regarded as the distance to the target rotor angle at time t2. That is, the control unit 5 can obtain the distance to the current target rotor angle by calculating the difference B according to the movement amount A in step S104.

Further, the control unit 5 calculates the motor torque based on the distance to the target rotor angle (step S105). In step S105, the command torque for the motor 2 is calculated using the difference between the current rotor angle and the target rotor angle. As shown in FIG. 6, the control unit 5 calculates the motor torque by PI control based on the difference B calculated at time t2. That is, the control unit 5 can calculate the motor torque using the distance to the target rotor angle obtained in step S104. In this case, the control unit 5 generates a command torque for the motor 2 based on the distance to the target rotor angle, and executes torque control for controlling the output torque of the motor 2 to achieve this command torque. This torque control is a control for stopping the rotor angle at the target stop position. That is, stop position control includes torque control for controlling motor torque to stop the rotor angle at the target stop position. The control unit 5 executes torque control and outputs a switching signal corresponding to the command torque to the inverter 3 .

Then, the control unit 5 determines whether or not the vehicle 1 has stopped (step S106). In step S106, it is determined whether or not the vehicle 1 has stopped based on signals input to the control unit 5 from various sensors. As shown in FIG. 6, the control unit 5 determines that the vehicle 1 has stopped at time t3. In addition, the evacuation control is continuously executed by the control unit 5 from steps S102 to S106.

If the vehicle 1 is not stopped (step S106: No), this control routine returns to step S104. In this way, while the process of step S104 and the process of step S105 are repeatedly performed, the stop position control is continuously performed by the control unit 5 . In other words, during steps S102 to S105, the inverter 3 remains in a state in which all phase elements of the upper arm are controlled to be ON, as shown in FIG.

When the vehicle 1 stops (step S106: Yes), the control unit 5 turns on the upper arm element of the failure phase, and turns on the lower arm element of the other phases (step S107). When the vehicle 1 stops, the controller 5 terminates the evacuation control. That is, the inertial running control and the stop position control are finished. Then, in step S107, the control unit 5 performs fuse blowing control.

In step S107, fuse blowing control is started, and as shown in FIG. 7, the faulty phase controls the upper arm element to ON, and the remaining two normal phases control the lower arm element to ON. do. As a result, overcurrent flows through the first fuse 6a corresponding to the U-phase, which is the faulty phase. In short, the failed switching element T1 is controlled to ON, and the remaining two phases are controlled to ON the switching elements T4 and T6 forming the arm opposite to the failed phase. As a result, an overcurrent can flow through the fuse 6 corresponding to the fault difference. The torque generated during fuse blowing control is torque that periodically takes a positive value and a negative value, as plotted by white dots in FIG.

The control unit 5 determines whether or not the fuse 6 of the faulty phase has blown (step S108). In step S108, it is determined whether or not the fuse 6 corresponding to the faulty phase among the fuses 6a, 6b and 6c provided for each phase has blown. In this control flow, since the faulty phase is the U phase, it is determined whether or not the first fuse 6a corresponding to the U phase has blown.

If the fuse 6 of the failed phase is not blown (step S108: No), this control routine returns to step S107.

When the fuse 6 of the faulty phase is blown (step S108: Yes), the control unit 5 drives the motor 2 by the two phases other than the faulty phase (step S109). In step S<b>109 , when the vehicle 1 transitions from the stopped state to the running state, the control unit 5 executes running control for outputting torque from the motor 2 .

In step S109, running control is started, and as shown in FIG. 8, the motor 2 is driven by the remaining two phases while the fuse 6 corresponding to the faulty phase is blown. In the example shown in FIG. 8, since the U-phase is the faulty phase, the motor 2 is driven by the remaining two phases, the V-phase and the W-phase, with the first fuse 6a blown. The torque generated by this two-phase drive is positive torque, as plotted by black dots in FIG.
After executing the process of step S109, this control routine ends.

As described above, according to the embodiment, the target value of the rotor angle is set in consideration of the case where the vehicle resumes running after the vehicle is stopped during the evacuation run, and the motor torque is increased so that the rotor angle can be stopped at the target value. Control. As a result, when an abnormality occurs in the switching element of the inverter 3, the rotor angle can be stopped at the target stop position when the vehicle 1 is evacuated. As a result, even when the vehicle is restarted by two-phase drive from a stopped state after the evacuation, the torque necessary for running can be output.

In the above-described embodiment, the case where the U-phase upper arm element fails has been described, but the present invention is not limited to this. That is, the faulty phase is not limited to the U phase, and may be the V phase or the W phase. Furthermore, the failed arm is not limited to the upper arm, and may be the lower arm. In short, during the inertia running control (step S102), the configuration for controlling all the phases of the upper arm elements of the inverter 3 to be ON has been described, but the present invention is not limited to this. During inertial running control, the control unit 5 may control all phases of the lower arm elements of the inverter 3 to be ON. For example, of the upper arm and the lower arm, the control unit 5 controls the arm including the switching element in which the abnormality is detected during running as the control object, and controls the elements of all the phases to ON. Therefore, when the switching element that detects the abnormality is the upper arm (when the failed arm is identified as the upper arm), the control unit 5 controls the upper arm elements to turn on all the phases. Alternatively, when the switching element that detects the abnormality is the lower arm (when the failed arm is identified as the lower arm), the control unit 5 controls the lower arm elements to turn on all the phases. In this manner, the control unit 5 can turn on all the phase switching elements of the upper arm or turn on all the phase switching elements of the lower arm in the inertial running control.

Further, the vehicle 1 is not limited to a front-wheel drive vehicle, and may be a rear-wheel drive vehicle. Furthermore, the vehicle 1 may be an electric vehicle capable of automatically traveling without being operated by the driver.

Moreover, a modification of the above-described embodiment can be constructed.

Here, the vehicle 1 in the first modified example will be described with reference to FIGS. 9 to 10. FIG. In the first modified example, it is taken into consideration that, even if the motor torque is calculated, it is not possible to output the torque according to the command torque because one switching element of the inverter 3 is out of order during limp driving.

FIG. 9 is a flow chart diagram showing a vehicle control flow in the first modified example. Note that steps S201 to S205 and S207 to S210 shown in FIG. 9 are the same processes as steps S101 to S109 shown in FIG.

After calculating the motor torque in step S205, the control unit 5 of the first modification calculates the difference between the command torque and the actual torque of the motor 2, integrates this difference, and adds it to the command torque (step S206). In step S206, correction control for correcting the command torque based on the actual torque is performed as torque control. That is, torque control includes correction control. The control unit 5 generates a correction command torque by integrating and adding the difference between the command torque and the actual torque, as indicated by a dashed line in FIG. 10, and controls the output torque of the motor 2 based on this correction command torque. .

According to this first modification, when coasting in a state where one phase switching element is out of order, the difference between the actual torque of the motor 2 and the command torque is added to the command torque, and the corrected command torque is obtained. By controlling the motor 2 by , the rotor angle can be stopped at the target stop position.

Further, the vehicle 1 in the second modified example will be described with reference to FIGS. 11 and 12. FIG. The second modified example is a further modified example of the first modified example, in which the distance to a stop is shortened by the driver's braking operation during evacuation running, and the vehicle stops short of the target rotor angle without reaching the target rotor angle. is taken into account. In addition, description is abbreviate|omitted about the structure similar to the 1st modification mentioned above.

FIG. 11 is a flow chart diagram showing a vehicle control flow in the second modified example. Note that steps S301 to S306 and S309 to S312 shown in FIG. 11 are the same processes as steps S201 to S210 shown in FIG.

After adding the difference between the command torque and the actual torque to the command torque in step S306, the control unit 5 of the second modification determines whether or not the brake pedal is depressed (step S307). In step S307, it is determined whether or not the driver is stepping on the brake pedal based on the signal from the brake stroke sensor.

If the brake pedal is depressed (step S307: Yes), the controller 5 changes the target rotor angle (step S308). In step S308, the distance to the target rotor angle is changed. When the control unit 5 detects a brake operation during stop position control, the control unit 5 shortens the distance to the target rotor angle by one rotation of the motor 2 as shown in FIG. 12 . That is, the distance to the target rotor angle is reduced by one rotation in accordance with the brake depression force.

If the brake pedal is not depressed (step S307: No), the control routine proceeds to step S308.

According to this second modification, when the brake pedal is depressed during stop position control, the rotor angle can be stopped at the target stop position by changing the distance to the target rotor angle.

Reference Signs List 1 vehicle 2 motor 3 inverter 4 battery 5 control unit 6 fuse 7 rotor angle sensor 10 drive system 11a, 12a, 13a upper arm 11b, 12b, 13b lower arm T1 to T6 switching element

Claims (8)

a three-phase electric motor as a power source for running;
an inverter having a plurality of switching elements and driving the three-phase electric motor;
a control device that controls the three-phase electric motor;
a rotor angle sensor that detects the rotor angle of the three-phase electric motor and outputs the detected value to the control device;
An electric vehicle comprising
When the control device detects an abnormality in one of the plurality of switching elements during running, the rotor angle of the three-phase motor when the vehicle is stopped is set to a predetermined value when driven by the remaining two phases. 1. An electric vehicle characterized by executing evacuation control for stopping the electric vehicle so as to achieve a target rotor angle capable of outputting the above torque. The evacuation running control includes:
Inertia running control for controlling the three-phase switching elements of the upper arm of the inverter to ON or controlling the three-phase switching elements of the lower arm to ON to decelerate the electric vehicle by inertia;
Calculation control for calculating the difference between the current rotor angle and the target rotor angle during execution of the inertial running control;
The electric vehicle according to claim 1, further comprising torque control for controlling the torque of the three-phase electric motor based on the difference and stopping the rotor angle at the target rotor angle. In the inertial running control, the control device controls to turn on the three-phase switching elements of the upper arm and the lower arm that include the switching element that detected the abnormality. The electric vehicle according to claim 2. The control device is
In the calculation control, calculating a distance from the current rotor angle to the target rotor angle,
In the torque control, calculating the torque of the three-phase electric motor based on the distance to the target rotor angle;
The distance to the target rotor angle is a value obtained by adding the angular difference from the current rotor angle to the target rotor angle to the product of the number of revolutions of the three-phase motor and 360. The electric vehicle according to claim 2 or 3. In the torque control, the torque calculated based on the distance to the target rotor angle is used as a command torque, and the difference between this command torque and the actual torque actually output from the three-phase electric motor is added to the command torque. The electric vehicle according to claim 4, further comprising correction control. The electric vehicle according to claim 5, wherein the control device changes the distance to the target rotor angle when detecting a brake pedal depression operation during execution of the evacuation control. A fuse is provided in a path electrically connecting the three-phase motor and the inverter,
2. When the electric vehicle is stopped after executing the evacuation control, the control device executes fusing control for fusing the fuse corresponding to the one phase in which the abnormality is detected. 7. The electric vehicle according to any one of 6. 8. The control device according to claim 7, wherein when the electric vehicle resumes running after executing the fusing control, the control device executes running control for driving the three-phase electric motor with the remaining two phases. electric vehicle.

Images