JP7643156B2 - Electric vehicles - Google Patents

Description

The present invention relates to an electric vehicle.

Patent Document 1 discloses that in an electric vehicle that runs on power output from a three-phase motor, if one phase of an inverter element fails while the vehicle is running, the remaining two phases drive the three-phase motor and the vehicle can run in an evacuation mode.

WO 13/008313

In the configuration described in Patent Document 1, when the vehicle is to be stopped for evacuation travel and then resume travel, the three-phase motor is driven by the remaining two phases. However, in the configuration described in Patent Document 1, the electric vehicle is stopped by inertia during evacuation travel, so the position at which the rotor angle of the three-phase motor stops is determined by inertia. Therefore, depending on the rotor angle of the three-phase motor when stopped, there is a risk that the torque required for travel cannot be output when travel is resumed from a stopped state by driving the two phases.

The present invention was made in consideration of the above circumstances, and aims to provide an electric vehicle that can output the torque required for running even when resuming running by two-phase drive from a stopped state after evacuation running.

The present invention is an electric vehicle equipped with a three-phase motor as a power source for traveling, an inverter having multiple switching elements and driving the three-phase motor, a control device for controlling the three-phase motor, and a rotor angle sensor that detects the rotor angle of the three-phase motor and outputs the detected value to the control device, and when an abnormality is detected in one phase of the multiple switching elements while traveling, the control device executes evacuation travel control to stop the electric vehicle so that the rotor angle of the three-phase 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.

With this configuration, when the vehicle resumes travelling from a stopped state after an evacuation run, the torque required for travelling can be output from the three-phase motor even when driven by the remaining two phases. This makes it possible to prevent a lack of driving force when travelling is resumed.

The evacuation travel control may also include coasting control for decelerating the electric vehicle by coasting by controlling the switching elements of the three phases of the upper arm of the inverter to ON or controlling the switching elements of the three phases of the lower arm to ON, calculation control for calculating the difference between the current rotor angle and the target rotor angle while the coasting control is being performed, and torque control for controlling the torque of the three-phase motor based on the difference and stopping the rotor angle at the target rotor angle.

According to this configuration, by executing the evacuation control, the difference between the current rotor angle and the target rotor angle during coasting can be calculated, and the torque of the three-phase motor can be controlled according to the difference so that the rotor angle stops at the target stop position.

In addition, the control device may control the three-phase switching elements to be on during the coasting control, targeting the arm that includes the switching element in which an abnormality has been detected, out of the upper arm and the lower arm.

With this configuration, the electric vehicle can be made to coast by controlling all phase elements to ON on the arm side that contains the switching element in which an abnormality has been detected.

In addition, the control device may calculate the distance from the current rotor angle to the target rotor angle in the calculation control, and calculate the torque of the three-phase motor based on the distance to the target rotor angle in the torque control, and the distance to the target rotor angle may be a value obtained by adding the angular difference from the current rotor angle to the target rotor angle multiplied by the rotation speed of the three-phase motor and 360.

With this configuration, during coasting, the torque of the three-phase 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.

The torque control may also include a correction control in which the torque calculated based on the distance to the target rotor angle is set as a command torque, and the difference between this command torque and the actual torque actually output from the three-phase motor is added to the command torque.

With this configuration, during coasting, the command torque can be corrected based on the difference between the actual torque actually output from the three-phase motor when driven by the remaining two phases and the command torque.

The control device may also change the distance to the target rotor angle if depression of the brake pedal is detected while the evacuation drive control is being performed.

With this configuration, if braking is detected during coasting, the electric vehicle stops earlier than the originally planned position, making it possible to change the distance to the target rotor angle.

Fuses may be provided in the path electrically connecting the three-phase motor and the inverter, and the control device may execute melting control to melt the fuse corresponding to the phase in which an abnormality is detected when the electric vehicle is stopped after executing the evacuation drive control.

According to this configuration, when the vehicle is stopped after evacuation travel, fuse blowing control can be executed to blow the fuse corresponding to the phase in which the abnormality was detected. This makes it possible to prevent current from flowing through the faulty phase when travel is subsequently resumed, improving safety against current flow.

The control device may also execute driving control to drive the three-phase motor using the remaining two phases when the electric vehicle resumes driving after executing the meltdown control.

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

In the present invention, when the vehicle resumes travel from a stopped state after an evacuation run, it is possible for the three-phase motor to output the torque required for travel even when driven by the remaining two phases. This makes it possible to prevent a lack of driving force when travel is resumed.

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

The following describes an electric vehicle according to an embodiment of the present invention in detail with reference to the drawings. Note that the present invention is not limited to the embodiment described below.

Figure 1 is a diagram showing a case where a failure occurs in a switching element of one phase of an inverter while an electric vehicle of an embodiment is running. Figure 2 is a diagram showing a schematic diagram of a drive system mounted on the electric vehicle.

As shown in Figures 1 and 2, vehicle 1 is an electric vehicle equipped with a motor 2 as a power source for driving. This vehicle 1 is, for example, a front-wheel drive vehicle in which the front left wheel and front right wheel are driven by power output from motor 2. Motor 2 is connected to the left and right drive wheels so that power can be transmitted via a power transmission device such as a transmission or a differential gear mechanism. Vehicle 1 is equipped with a drive system 10 for controlling the torque required for driving.

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

In the drive system 10, the DC power output from the battery 4 is converted to AC power by the inverter 3, and this AC power is supplied from the inverter 3 to the motor 2, thereby driving the motor 2. At that time, the drive of the motor 2 is controlled by a command signal output from the control unit 5 to the inverter 3. The control unit 5 controls the inverter 3 and the motor 2. The drive system 10 is provided with a smoothing capacitor C. The control device of the vehicle 1 is also configured to include at least the control unit 5.

The motor 2 is electrically connected to the battery 4 via the inverter 3, and is driven by the power supplied from the 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. This motor 2 is a three-phase motor, and is also a motor generator (MG) that can function as both an electric motor and a generator.

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

The upper and lower arms 11 of the U phase have 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 upper arm 11a and the lower arm 11b are connected in series. The upper and lower arms 12 of the V phase have 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 upper arm 12a and the lower arm 12b are connected in series. The upper and lower arms 13 of the W phase have 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 upper arm 13a and the lower arm 13b are connected in series.

In addition, in the drive system 10, a fuse 6 is provided in the path that electrically connects the inverter 3 and the motor 2. The fuse 6 is disposed on the path corresponding to the coil of each phase, and melts when a current of a predetermined magnitude or greater flows. The fuse 6 is composed of 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 6a is disposed between the connection point of the U-phase upper arm 11a and the lower arm 11b and the U-phase coil of the motor 2. When the U-phase current becomes greater than a predetermined value, the first fuse 6a melts. The second fuse 6b is disposed between the connection point of the V-phase upper arm 12a and the lower arm 12b and the V-phase coil of the motor 2. When the V-phase current becomes greater than a predetermined value, the second fuse 6b melts. The third fuse 6c is disposed between the connection point of the W-phase upper arm 13a and the lower arm 13b and the W-phase coil of the motor 2. When the W-phase current becomes greater than a predetermined value, the third fuse 6c melts.

The control unit 5 is composed of an electronic control unit (ECU) that drives and controls the motor 2. The control unit 5 is composed of a microcomputer having a CPU, RAM, ROM, an input/output interface, etc. Furthermore, 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 control unit 5. The control unit 5 performs calculations for motor control, such as calculating the rotation speed of the motor 2 (hereinafter referred to as the motor rotation speed) based on the input signal.

As a result of the calculation, a command signal for controlling the inverter 3 is output from the control unit 5 to the inverter 3. The command signal to the inverter 3 includes a signal for switching the switching element, of the multiple switching elements T1 to T6, that is to be the object of switching operation control. In this way, the control unit 5 controls the voltage and current applied to the motor 2 by controlling the inverter 3.

As shown in FIG. 1, the control unit 5 executes evacuation drive control when a failure (e.g., a short circuit failure) occurs in one of the switching elements of the inverter 3 during driving. The evacuation drive control is executed as a fail-safe against element failure in the inverter 3, and is a control for safely stopping the vehicle 1 while driving. For this reason, the vehicle 1 is provided with an element failure detector (ON failure detector) that detects the occurrence of an ON failure 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 the occurrence of an ON failure in 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 unit 5. In this way, the control unit 5 can determine whether an element failure has occurred in the inverter 3 based on the detection signal from the element failure detector. Here, an example of vehicle control executed by the control unit 5 is shown in FIG. 3.

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

The control unit 5 determines whether an ON fault has occurred in one of the switching elements of one phase of the inverter 3 while the vehicle is running (step S101). In step S101, it is determined whether an ON fault has occurred in one of the switching elements T1 to T6 of the inverter 3. In other words, it is determined whether an abnormality has occurred in one of the six switching elements T1 to T6. The control unit 5 can determine whether an ON fault has occurred in a switching element based on a detection signal from the element fault detector.

If the switching elements T1 to T6 of the inverter 3 do not have an ON failure while driving (step S101: No), this control routine ends.

If an ON fault occurs in one of the switching elements of the inverter 3 during driving (step S101: Yes), the control unit 5 controls the switching elements of all phases in the upper arm of the inverter 3 to ON (step S102). In step S102, the control unit 5 starts evacuation driving control.

In step S102, as shown in FIG. 4, the evacuation drive control is started, and the switching elements of all phases of the upper and lower arms, whichever arm includes the faulty switching element, are controlled to be ON. In this case, the faulty switching element is identified before the switching elements of the upper arm are controlled to be ON in all phases in step S102. That is, when the control unit 5 detects an abnormality in the inverter 3, it determines whether the arm of the faulty switching element (hereinafter, sometimes referred to as the faulty arm) is the upper arm or the lower arm, and determines whether the phase of the faulty switching element (hereinafter, sometimes referred to as the faulty phase) is the U phase, V phase, or W phase. This determination process makes it possible to identify which element of the six switching elements T1 to T6 is the faulty element. This identification process (discrimination process) is performed, for example, in the determination process of step S101, after a positive 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 in the faulty arm. That is, in the failed arm, the elements are controlled to be ON in the phases other than the failed phase. In this way, the control unit 5 starts the evacuation travel control in step S102, and controls the switching elements of the upper arm to be ON in all phases, thereby slowing down the vehicle 1 by coasting. The evacuation travel control includes control for decelerating the vehicle 1 by coasting (hereinafter referred to as coasting control). Therefore, in step S102, the coasting control is executed, and the vehicle 1 coasts.

In this control flow, an example will be described in which the faulty element is switching element T1. In other words, when it is determined that an ON fault has occurred in the switching element of one of the phases of inverter 3, the upper arm element of U phase is identified as the faulty element. Therefore, the control unit 5 controls the switching elements of all phases to ON, targeting the upper arm that includes the faulty element.

Also, the control unit 5 calculates the distance to the target rotor angle during coasting (step S103). The target rotor angle is the target stop position of the rotor angle when the vehicle 1 stops. The control unit 5 executes the evacuation running control while traveling, safely stops the vehicle 1, and controls the motor torque so that the rotor angle at the time of stopping becomes the target rotor angle, taking into consideration that the vehicle 1 will start traveling again after stopping. That is, the control unit 5 executes, as the evacuation running control, a coasting control that turns on the elements of all phases of the upper arm, and a stop position control that controls the torque of the motor 2 to control the stop position of the rotor angle. That is, the evacuation running control includes a stop position control. Then, when traveling is resumed from the stopped state after the evacuation running, the motor 2 is driven by the remaining two phases that are not faulty. Therefore, when the motor 2 is driven by the remaining two phases, the target rotor angle is set so that the rotor angle is capable of outputting a torque of a predetermined value or more. In this case, the target rotor angle can be set according to the faulty phase. For example, if the U-phase switching element has an ON failure, the angle range of the target rotor angle that can be set is fixed, so the control unit 5 can identify the failed phase and then set the target rotor angle within that range according to the failed phase. This target rotor angle can be set by selecting a predetermined value within a certain angle range, for example, within a range of about 20°. Furthermore, within the range of 0 to 360 for one rotor rotation, there are multiple 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 identified 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 for calculating the distance to the target rotor angle will be described with reference to FIG. 5. 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 (angle difference) between the current rotor angle and the target rotor angle as an angle difference within the range of 0 to 360. 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 the target rotor angle = (angle difference between the target value and the current value) + 360 x N". N is the motor rotation speed. In this way, the distance to the target rotor angle is a value obtained by adding the angle difference from the current rotor angle to the target rotor angle within the range of 0 to 360, the motor rotation speed, and 360. In step S103, the distance to the target rotor angle at the start of the evacuation travel control is calculated. That is, in step S103, the 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 a calculation control that calculates the difference between the current rotor angle and the target rotor angle, and a calculation control that calculates 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 start of the evacuation travel control 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 travel control (time t1), and calculates the amount of movement A of the rotor angle thereafter (time t2). At that 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. Then, the control unit 5 calculates the amount of movement A of the rotor angle at time t2, thereby being able to calculate the difference B between the distance to the target rotor angle (the target value calculated at time t1) and the amount of movement A (the value calculated at time t2). This difference B can be regarded as the distance to the target rotor angle at time t2. In other words, the control unit 5 can obtain the distance to the target rotor angle at the present time by calculating the difference B according to the amount of movement A in step S104.

The control unit 5 also calculates the motor torque based on the distance to the target rotor angle (step S105). In step S105, the command torque of 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 of the motor 2 based on the distance to the target rotor angle, and executes torque control to control the output torque of the motor 2 to become this command torque. This torque control is a control for stopping the rotor angle at the target stop position. In other words, the stop position control includes torque control for controlling the motor torque to stop the rotor angle at the target stop position. The control unit 5 executes torque control and outputs a switching signal according to the command torque to the inverter 3.

Then, the control unit 5 determines whether the vehicle 1 has stopped (step S106). In step S106, it is determined whether the vehicle 1 has stopped based on signals input from various sensors to the control unit 5. As shown in FIG. 6, the control unit 5 determines that the vehicle 1 has stopped at time t3. In addition, between steps S102 and S106, the control unit 5 continues to execute the evacuation driving control.

If the vehicle 1 is not stopped (step S106: No), the control routine returns to step S104. Thus, while the processing of step S104 and the processing of step S105 are repeatedly performed, the control unit 5 continues to execute the stop position control. In other words, between steps S102 and S105, the inverter 3 remains in a state in which the elements of all phases of the upper arm are controlled to be ON, as shown in FIG. 4.

When the vehicle 1 is stopped (step S106: Yes), the control unit 5 controls the upper arm element of the faulty phase to ON, and controls the lower arm elements of the other phases to ON (step S107). When the vehicle 1 is stopped, the control unit 5 ends the evacuation travel control. In other words, the coasting control and the stop position control end. Then, in step S107, the control unit 5 executes fuse blowing control.

In step S107, fuse blowout control is started, and as shown in FIG. 7, the upper arm element of the faulty phase is controlled to ON, and the lower arm elements of the remaining two normal phases are controlled to ON. This causes an overcurrent to flow through the first fuse 6a corresponding to the faulty phase U-phase. In short, the faulty switching element T1 is controlled to ON, and the remaining two phases control the switching elements T4 and T6 constituting the arm opposite the faulty phase to ON. As a result, an overcurrent can be caused to flow through the fuse 6 corresponding to the faulty phase. In addition, the torque generated during fuse blowout control is a torque that periodically becomes positive and negative, as plotted by the white dots in FIG. 5.

The control unit 5 determines whether the fuse 6 of the faulty phase has blown (step S108). In step S108, it is determined whether the fuse 6 corresponding to the faulty phase among the fuses 6a, 6b, and 6c provided in each phase has blown. In this control flow, since the faulty phase is the U phase, it is determined whether the first fuse 6a corresponding to the U phase has blown.

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

If the fuse 6 of the faulty phase is blown (step S108: Yes), the control unit 5 drives the motor 2 with the two phases other than the faulty phase (step S109). In step S109, when the vehicle 1 transitions from a stopped state to a running state, the control unit 5 executes running control to cause the motor 2 to output torque.

In step S109, the driving control is started, and the motor 2 is driven by the remaining two phases with the fuse 6 corresponding to the faulty phase blown, as shown in Fig. 8. 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 driving with these two phases is a positive torque, as plotted by black dots in Fig. 5.
After the process of step S109 is performed, this control routine ends.

As described above, according to the embodiment, a target value for the rotor angle is set in consideration of the case where the vehicle is driven again after stopping during evacuation driving, and the motor torque is controlled so that the rotor angle can be stopped at the target value. As a result, if 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 driven to evacuation. This makes it possible to output the torque required for driving, even when driving is resumed by two-phase drive from a stopped state after evacuation driving.

In the above embodiment, the case where the upper arm element of the U phase has failed has been described, but the present invention is not limited to this. In other words, the failed phase is not limited to the U phase, but may be the V phase or the W phase. Furthermore, the failed arm is not limited to the upper arm, but may be the lower arm. In short, the configuration in which the upper arm elements of the inverter 3 are controlled to be ON in all phases during coasting control (step S102) has been described, but the present invention is not limited to this. During coasting control, the control unit 5 may control the lower arm elements of the inverter 3 to be ON in all phases. For example, the control unit 5 controls the elements of all phases to be ON by controlling the arm including the switching element in which an abnormality was detected during running, out of the upper arm and the lower arm, as the control object. Therefore, if the switching element in which the abnormality was detected is the upper arm (if the failed arm is identified as the upper arm), the control unit 5 controls the upper arm elements to be ON in all phases. Alternatively, if the switching element in which the abnormality was detected is the lower arm (if the failed arm is identified as the lower arm), the control unit 5 controls the lower arm elements to be ON in all phases. In this way, during coasting control, the control unit 5 can control all phases of the switching elements of the upper arm to be ON, or control all phases of the switching elements of the lower arm to be ON.

Vehicle 1 is not limited to a front-wheel drive vehicle, and may be a rear-wheel drive vehicle. Furthermore, vehicle 1 may be an electric vehicle capable of autonomous driving without operation by a driver.

Modifications of the above-described embodiments can also be made.

Now, referring to Figures 9 and 10, the vehicle 1 in the first modified example will be described. In the first modified example, it is taken into consideration that, during evacuation travel, one of the switching elements of the inverter 3 fails, so even if the motor torque is calculated, it is not possible to output the torque according to the command torque.

Figure 9 is a flow chart showing the vehicle control flow in the first modified example. Note that steps S201 to S205 and S207 to S210 shown in Figure 9 are the same processes as steps S101 to S109 shown in Figure 4.

When the control unit 5 of the first modified example calculates the motor torque in step S205, it 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 is performed as the torque control to correct the command torque based on the actual torque. In other words, the torque control includes correction control. As shown by the dashed dotted line in FIG. 10, the control unit 5 generates a corrected command torque by integrating and adding the difference between the command torque and the actual torque, and controls the output torque of the motor 2 based on this corrected command torque.

According to this first modified example, when coasting with one phase of a switching element failing, the difference between the actual torque and command torque of motor 2 is added to the command torque, and motor 2 is controlled by the corrected command torque, so that the rotor angle can be stopped at the target stop position.

Furthermore, with reference to Figures 11 and 12, a vehicle 1 in a second modified example will be described. The second modified example is a further modified example of the first modified example, and takes into consideration the fact that, during evacuation travel, the driver's braking operation shortens the distance to stopping, causing the vehicle to stop short of the target rotor angle. Note that a description of the same configuration as the first modified example described above will be omitted.

Figure 11 is a flow chart showing the vehicle control flow in the second modified example. Note that steps S301 to S306 and S309 to S312 shown in Figure 11 are the same processes as steps S201 to S210 shown in Figure 9.

In the second modified example, when the control unit 5 adds the difference between the command torque and the actual torque to the command torque in step S306, it determines whether the brake pedal is being depressed (step S307). In step S307, it is determined whether the driver is depressing the brake pedal based on a signal from the brake stroke sensor.

If the brake pedal is depressed (step S307: Yes), the control unit 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, it changes the distance to the target rotor angle so as to be shorter by one rotation of the motor 2, as shown in FIG. 12. In other words, 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 variant, if 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 elements

Claims (1)

A three-phase motor that is the power source for running the vehicle;
an inverter having a plurality of switching elements and driving the three-phase motor;
A control device for controlling the three-phase motor;
a rotor angle sensor that detects a rotor angle of the three-phase motor and outputs the detected value to the control device;
An electric vehicle comprising:
when an abnormality is detected in one phase of the plurality of switching elements while the vehicle is traveling, the control device executes an evacuation travel control to stop the electric vehicle so that a rotor angle of the three-phase motor when the vehicle is stopped becomes a target rotor angle that can output a torque of a predetermined value or more when driven by the remaining two phases.

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