electric vehicles

Abstract

When an overcurrent is detected in either the first or second inverter phase, it is possible to determine whether the upper arm or lower arm of the overcurrent phase is short-circuited. [Solution] When an electric vehicle detects an overcurrent in any phase of the first inverter, it performs a shutdown process for both the first and second inverters, and determines whether the first upper arm or the first lower arm of the first overcurrent phase is short-circuited based on the sign of the current offset value of the first overcurrent phase, which is the overcurrent phase of the first inverter. When an overcurrent is detected in any phase of the second inverter, it performs a shutdown process for both the first and second inverters, and determines whether the second upper arm or the second lower arm of the second overcurrent phase is short-circuited based on the sign of the current offset value of the second overcurrent phase, which is the overcurrent phase of the second inverter.

Description

Technical Field

[0001] The present disclosure relates to electric vehicles.

Background Art

[0002] Conventionally, an electric vehicle has been proposed that includes a power storage device, a motor having a three-phase open winding, a first inverter that is connected to a positive electrode side line and a negative electrode side line to which the power storage device is connected, is connected to one end side of the three-phase open winding, and has three-phase first upper arms and three-phase first lower arms, and a second inverter that is connected to the positive electrode side line and the negative electrode side line on the opposite side of the power storage device from the first inverter, is connected to the other end side of the three-phase open winding, and has three-phase second upper arms and three-phase second lower arms (see, for example, Patent Document 1). In this electric vehicle, current sensors are attached to each phase of the three-phase open winding, and when driving the motor in H drive by the first and second inverters, an abnormality diagnosis of the current sensors of each phase is performed based on the sum of the phase currents of each phase.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In such electric vehicles, when an overcurrent in any phase of the first inverter or the second inverter is detected, there is a need for devising a method for determining which of the upper arm and the lower arm of the overcurrent phase, which is the phase with the overcurrent, has a short-circuit abnormality. The main object of the electric vehicle of the present disclosure is to be able to determine which of the upper arm and the lower arm of the phase with the overcurrent has a short-circuit abnormality when an overcurrent in any phase of the first inverter or the second inverter is detected.

Means for Solving the Problems

[0005] The electric vehicle of this disclosure employs the following means to achieve the main objective described above. The electric vehicle of this disclosure comprises: an energy storage device; a motor having a three-phase open winding; a first inverter connected to a first positive line and a first negative line to which the energy storage device is connected, and connected to one end of the three-phase open winding, and having a three-phase first upper arm and a three-phase first lower arm; a second inverter connected to the first positive line and the first negative line on the opposite side of the first inverter from the energy storage device, and connected to the other end of the three-phase open winding, and having a three-phase second upper arm and a three-phase second lower arm; and a control device, wherein the control device controls any of the first inverters The gist of this is that when an overcurrent is detected in the phase, the shutdown process of the first and second inverters is executed, and it is determined which of the first upper arm and the first lower arm of the first overcurrent phase is short-circuited based on the sign of the current offset value of the first overcurrent phase, which is the overcurrent phase of the first inverter. If an overcurrent is detected in any phase of the second inverter, the shutdown process of the first and second inverters is executed, and it is determined which of the second upper arm and the second lower arm of the second overcurrent phase is short-circuited based on the sign of the current offset value of the second overcurrent phase, which is the overcurrent phase of the second inverter.

[0006] In the electric vehicle of this disclosure, when an overcurrent is detected in any phase of the first inverter, the shutdown process of the first and second inverters is executed, and it is determined which of the first upper arm and the first lower arm of the first overcurrent phase is short-circuited based on the sign of the current offset value of the first overcurrent phase, which is the phase of the overcurrent in the first inverter. When an overcurrent is detected in any phase of the second inverter, the shutdown process of the first and second inverters is executed, and it is determined which of the second upper arm and the second lower arm of the second overcurrent phase is short-circuited based on the sign of the current offset value of the second overcurrent phase, which is the phase of the overcurrent in the second inverter. When the motor is rotating when the shutdown process of the first and second inverters is executed, a current based on the back electromotive force generated by the rotation of the motor flows through each phase of the motor. At this time, a current offset occurs in the phase containing the arm with the short-circuit problem, so it is possible to determine which of the upper arm and the lower arm of the overcurrent phase is short-circuited based on the sign of the current offset value.

[0007] The electric vehicle of the present disclosure further comprises: a first switch provided between the energy storage device and the first inverter on the first positive side line; a second switch provided between the first and second inverters on the first positive side line; a third switch provided between the energy storage device and the first inverter on the first negative side line; a fourth switch provided between the first and second inverters on the first negative side line; a fifth switch provided on the second positive side line connecting the energy storage device side of the first switch on the first positive side line and the second inverter side of the second switch on the second switch; and a sixth switch provided on the second negative side line connecting the energy storage device side of the third switch on the first negative side line and the second inverter side of the fourth switch on the first negative side line, wherein the control device detects a short circuit abnormality in any of the three phases of the first upper arm, and turns on the third, fourth, and fifth switches or turns on the fifth and sixth switches and the three If a short-circuit abnormality is detected in any of the three phases' first lower arms, the first, second, and sixth switches are turned on, or the fifth and sixth switches are turned on, and the first phase's first lower arm is turned on, and the second inverter is switched on. If a short-circuit abnormality is detected in any of the three phases' second upper arms, the first, third, and fourth switches are turned on, or the first, third, and sixth switches are turned on, or the first and third switches are turned on, and the second phase's second upper arm is turned on, and the first inverter is switched on. If a short-circuit abnormality is detected in any of the three phases' second lower arms, the first, second, and third switches are turned on, or the first, third, and fifth switches are turned on, or the first and third switches are turned on, and the second phase's second lower arm is turned on, and the first inverter is switched on. This allows the system to retract according to the location of the short-circuit anomaly among the three phases: the first upper arm, the first lower arm, the second upper arm, and the second lower arm. [Brief explanation of the drawing]

[0008] [Figure 1]This is a schematic diagram of the electric vehicle according to the embodiments of the present disclosure. [Figure 2] This is a flowchart showing an example of a short-circuit abnormality element detection routine. [Figure 3] This is an explanatory diagram showing an example of the phase current waveform for each phase when the first upper arm or first lower arm of the U phase is short-circuited. [Figure 4] This is an explanatory diagram showing an example of the phase current waveform for each phase when there is a short-circuit abnormality in the second upper arm or second lower arm of the U phase. [Figure 5] This is a flowchart showing an example of a control routine for evasive maneuvers. [Figure 6] This is an explanatory diagram showing an example of the first evasive driving control procedure. [Modes for carrying out the invention]

[0009] Embodiments for implementing this disclosure will be described with reference to the drawings. Figure 1 is a schematic diagram of an electric vehicle 10 according to an embodiment of this disclosure. As shown in the figure, the electric vehicle 10 of the embodiment includes a battery 12 as an energy storage device, a motor 20, first and second inverters 22 and 24, first to sixth switches SW1 to SW6, a capacitor 30, and an electronic control unit (hereinafter referred to as "ECU") 50 as a control device.

[0010] The battery 12 is configured as, for example, a lithium-ion secondary battery or a nickel-metal hydride secondary battery and is connected to the first positive electrode line 16p and the first negative electrode line 16n. The motor 20 is configured as a three-phase AC motor and comprises a rotor in which permanent magnets are embedded in the rotor core and a stator in which three-phase (U-phase, V-phase, W-phase) coils (three-phase open windings) are wound around the stator core. The rotor is connected to a drive shaft which is linked to the drive wheel via a differential gear.

[0011] The first and second inverters 22 each comprise six transistors T11-T16 and T21-T26 as multiple switching elements, and six diodes D11-D16 and D21-D26 connected in parallel to each of the six transistors T11-T16 and T21-T26. Examples of transistors T11-T16 and T21-T26 include MOSFETs and IGBTs. The transistors T11-T16 and T21-T26 are arranged in pairs, with two transistors acting as the source and sink sides with respect to the first positive line 16p and the first negative line 16n. The connection points of transistors T11 and T14, T12 and T15, and T13 and T16 are connected to one end of the U-phase, V-phase, and W-phase coils of the motor 20 via U-phase, V-phase, and W-phase lines 21u, 21v, and 21w, respectively. The connection points of transistors T21 and T24, T22 and T25, and T23 and T26 are connected to the other ends of the U-phase, V-phase, and W-phase coils of the motor 20 via U-phase, V-phase, and W-phase lines 23u, 23v, and 23w, respectively. Hereinafter, transistors T11 to T13 and diodes D11 to D13 may be referred to as the "first upper arm," transistors T14 to T16 and diodes D14 to D16 as the "first lower arm," transistors T21 to T23 and diodes D21 to D23 as the "second upper arm," and transistors T24 to T26 and diodes D24 to D26 as the "second lower arm." The first inverter 22 further includes overcurrent detection circuits 22u, 22v, and 22w for detecting overcurrents in the U-phase, V-phase, and W-phase lines 21u, 21v, and 21w, respectively. The second inverter 24 further includes overcurrent detection circuits 24u, 24v, and 24w for detecting overcurrents in the U-phase, V-phase, and W-phase lines 23u, 23v, and 23w, respectively. The overcurrent detection circuits 22u, 22v, 22w, 24u, 24v, and 24w are designed so that if an overcurrent is detected on one side, either the first inverter 22 or the second inverter 24, the other side will not detect an overcurrent, taking into account that the current is attenuated by the RL component of the three-phase coils of the motor 20.

[0012] The first switch SW1 is located between the battery 12 and the first inverter 22 on the first positive side line 16p. The second switch SW2 is located between the first and second inverters 22 and 24 on the first positive side line 16p. The third switch SW3 is located between the battery 12 and the first inverter 22 on the first negative side line 16n. The fourth switch SW4 is located between the first and second inverters 22 and 24 on the first negative side line 16n. The fifth switch SW5 is located on the second positive side line 17p, which connects the first positive side line 16p to the battery 12 side of the first positive side line 16p beyond the first switch SW1, and to the second inverter 24 side of the first positive side line 16p beyond the second switch SW2. The sixth switch SW6 is located on the second negative side line 17n, which connects the third switch SW3 of the first negative side line 16n to the battery 12 side, and the fourth switch SW4 of the first negative side line 16n to the second inverter 24 side. The capacitor 30 is connected to the first positive side line 16p and the first and third switches SW1 and SW3 of the first negative side line 16n to the battery 12 side.

[0013] The ECU50 is a microcomputer equipped with a CPU, ROM, RAM, flash memory, input / output ports, and communication ports, as well as various drive circuits and various logic ICs. Signals from various sensors are input to the ECU50. For example, the ECU50 receives the voltage Vb of the battery 12 from the voltage sensor 12v, the current Ib of the battery 12 from the current sensor 12i, and the temperature Tb of the battery 12 from the temperature sensor 12t. The ECU50 also receives the rotational position θm of the rotor of the motor 20 from the rotational position sensor 20a, and the phase currents Iu, Iv, Iw of the U-phase, V-phase, and W-phase of the motor 20 from the current sensors 20u, 20v, and 20w (when the direction of the motor 20 from the first inverter 22 is positive). ECU50 also receives signals from the overcurrent detection circuits 22u, 22v, 22w regarding the presence or absence of overcurrent in the U-phase, V-phase, and W-phase lines 21u, 21v, 21w, as well as signals from the overcurrent detection circuits 24u, 24v, 24w regarding the presence or absence of overcurrent in the U-phase, V-phase, and W-phase lines 23u, 23v, 23w, and the voltage VH of capacitor 30 from the voltage sensor 30v. ECU50 also receives on / off signals from the power switch, shift position SP (shift lever operation position) from the shift position sensor, accelerator opening Acc (accelerator pedal depression amount) from the accelerator pedal position sensor, brake pedal position BP (brake pedal depression amount) from the brake pedal position sensor, and vehicle speed V from the vehicle speed sensor.

[0014] Various control signals are output from the ECU 50. For example, the ECU 50 outputs control signals to transistors T11-T16 and T21-T26 of the first inverters 22 and 24, and to switches SW1-SW6 of the first to sixth switches. The ECU 50 calculates the state of charge (SOC) of the battery 12 based on the integrated value of the current Ib of the battery 12, and calculates the rotational speed Nm of the motor 20 based on the rotational position θm of the rotor of the motor 20.

[0015] In the electric vehicle 10 of this embodiment, the ECU 50 basically turns on the first to fourth switches SW1 to SW4 and turns off the fifth and sixth switches SW5 and SW6. Then, it sets the required torque Td* required for driving based on the accelerator opening Acc and the vehicle speed V, sets the torque command Tm* for the motor 20 to drive with the set required torque Td*, and switches the transistors T11 to T16 and T21 to T26 of the first and second inverters 22 and 24 so that the motor 20 is driven by the torque command Tm*. Hereinafter, driving the motor 20 by switching the first and second inverters 22 and 24 will be referred to as "H drive".

[0016] Next, the operation of the electric vehicle 10 of the embodiment will be described, in particular, when a short-circuit abnormality occurs in any of the transistors T11-T16 or T21-T26 of the first and second inverters 22 and 24 while driving in H drive mode. Figure 2 is a flowchart of an example of a short-circuit abnormality element detection routine executed by the ECU 50. This routine is executed when the ECU 50 detects an overcurrent in any of the U-phase, V-phase, and W-phase lines 21u, 21v, 21w and U-phase, V-phase, and W-phase lines 23u, 23v, 23w based on signals from the overcurrent detection circuits 22u, 22v, 22w, 24u, 24v, 24w.

[0017] When this routine is executed, the ECU 50 first performs the shutdown process for the first and second inverters 22 and 24, that is, it controls the first and second inverters 22 and 24 so that all transistors T11 to T16 and T21 to T26 are turned off (step S100). When the shutdown process for the first and second inverters 22 and 24 is performed while driving (while the motor 20 is rotating), current based on the back electromotive force generated by the rotation of the motor 20 flows through each phase of the motor 20.

[0018] Subsequently, it is determined which of the first inverter 22 (overcurrent detection circuits 22u, 22v, 22w) and the second inverter 24 (overcurrent detection circuits 24u, 24v, 24w) detected the overcurrent (step S110). When it is determined that the first inverter 22 detected the overcurrent, it is determined which of the overcurrent detection circuits 22u, 22v, 22w detected the overcurrent (which of the U-phase, V-phase, and W-phase is the overcurrent phase) (step S120).

[0019] When it is determined in step S120 that the overcurrent detection circuit 22u of the U-phase detected the overcurrent (the U-phase is the overcurrent phase), the offset value Iuos of the phase current Iu of the U-phase is calculated (step S130), and the sign of the calculated offset value Iuos is examined (step S132). Here, the offset value Iuos is obtained, for example, by applying a low-pass filter (LPF) to the phase current Iu when the shutdown process of the first and second inverters 22 and 24 is being executed. FIG. 3 is an explanatory diagram showing an example of the waveforms of the phase currents Iu, Iv, and Iw of each phase when the first upper arm (transistor T11) or the first lower arm (transistor T14) of the U-phase has a short-circuit abnormality. FIG. 3(A) shows the case where the first upper arm of the U-phase has a short-circuit abnormality, and FIG. 3(B) shows the case where the first lower arm of the U-phase has a short-circuit abnormality. FIGS. 3(A) and 3(B) are obtained by analysis. As shown in FIG. 3(A), when the first upper arm of the U-phase has a short-circuit abnormality, the phase current Iu is offset to the positive side. On the other hand, as shown in FIG. 3(B), when the first lower arm has a short-circuit abnormality, the phase current Iu is offset to the negative side.

[0020] Based on these, when it is determined in step S132 that the sign of the offset value Iuos is positive, it is determined that the first upper arm (transistor T11) of the U-phase has a short-circuit abnormality (step S134), and this routine is terminated. On the other hand, when it is determined that the sign of the offset value Iuos is negative, it is determined that the first lower arm (transistor T14) of the U-phase has a short-circuit abnormality (step S136), and this routine is terminated. In this way, it is possible to discriminate which of the first upper arm and the first lower arm of the U-phase has a short-circuit abnormality.

[0021] When it is determined in step S120 that an overcurrent has been detected by the overcurrent detection circuit 22v for the V-phase (the V-phase is the overcurrent phase), an offset value Ivos of the phase current Iv of the V-phase is calculated (step S140), and the sign of the calculated offset value Ivos is examined (step S142). Here, the offset value Ivos is obtained in the same manner as the offset value Iuos. Also, the sign of the offset value Ivos is the same as in FIGS. 4(A) and 4(B). Therefore, when it is determined that the sign of the offset value Ivos is positive, it is determined that the first upper arm (transistor T12) of the V-phase has a short-circuit abnormality (step S144), and this routine is terminated. On the other hand, when it is determined that the sign of the offset value Ivos is negative, it is determined that the first lower arm (transistor T15) of the V-phase has a short-circuit abnormality (step S146), and this routine is terminated. In this way, it is possible to discriminate which of the first upper arm and the first lower arm of the V-phase has a short-circuit abnormality.

[0022] When it is determined in step S120 that an overcurrent has been detected by the overcurrent detection circuit 22w for the W-phase (the W-phase is the overcurrent phase), an offset value Iwos of the phase current Iw of the W-phase is calculated (step S150), and the sign of the calculated offset value Iwos is examined (step S152). Here, the offset value Iwos is obtained in the same manner as the offset value Iuos. Also, the sign of the offset value Iwos is the same as in FIGS. 4(A) and 4(B). Therefore, when it is determined that the sign of the offset value Iwos is positive, it is determined that the first upper arm (transistor T13) of the W-phase has a short-circuit abnormality (step S154), and this routine is terminated. On the other hand, when it is determined that the sign of the offset value Iwos is negative, it is determined that the first lower arm (transistor T16) of the W-phase has a short-circuit abnormality (step S156), and this routine is terminated. In this way, it is possible to discriminate which of the first upper arm and the first lower arm of the W-phase has a short-circuit abnormality.

[0023] If it is determined in step S110 that an overcurrent has been detected in the second inverter 24, it is determined in step S160 which of the overcurrent detection circuits 24u, 24v, or 24w detected the overcurrent (which of the U-phase, V-phase, or W-phase is the overcurrent phase). If it is determined that an overcurrent has been detected in the U-phase overcurrent detection circuit 24u (the U-phase is the overcurrent phase), the offset value Iuos of the U-phase phase current Iu is calculated (step S170), and the sign of the calculated offset value Iuos is checked (step S172). Figure 4 is an explanatory diagram showing an example of the waveforms of the phase currents Iu, Iv, and Iw of each phase when the second upper arm (transistor T21) or second lower arm (transistor T24) of the U-phase is short-circuited. Figure 4(A) shows the case when the second upper arm of the U-phase is short-circuited, and Figure 4(B) shows the case when the second lower arm of the U-phase is short-circuited. Figures 4(A) and 4(B) were obtained through analysis. As shown in Figure 4(A), when the first upper arm of the U phase is short-circuited, the phase current Iu is offset to the negative side. On the other hand, as shown in Figure 4(B), when the first lower arm is short-circuited, the phase current Iu is offset to the positive side.

[0024] Based on these factors, if the sign of the offset value Iuos is determined to be negative in step S172, it is determined that the second upper arm of the U phase (transistor T21) has a short-circuit abnormality (step S174), and this routine terminates. On the other hand, if the sign of the offset value Iuos is determined to be positive, it is determined that the second lower arm of the U phase (transistor T24) has a short-circuit abnormality (step S176), and this routine terminates. In this way, it is possible to determine whether the short-circuit abnormality is in the second upper arm or the second lower arm of the U phase.

[0025] If the V-phase overcurrent detection circuit 24V detects an overcurrent in step S160 (indicating that the V-phase is an overcurrent phase), the offset value Ivos of the V-phase phase current Iv is calculated (step S180), and the sign of the calculated offset value Ivos is checked (step S182). Here, the sign of the offset value Ivos is the same as in Figures 4(A) and 4(B). Therefore, if the sign of the offset value Ivos is determined to be negative, it is determined that the second upper arm of the V-phase (transistor T22) is short-circuited (step S184), and this routine is terminated. On the other hand, if the sign of the offset value Ivos is determined to be positive, it is determined that the second lower arm of the V-phase (transistor T25) is short-circuited (step S186), and this routine is terminated. In this way, it is possible to determine whether the short-circuited abnormality is in the second upper arm or the second lower arm of the V-phase.

[0026] If the W-phase overcurrent detection circuit 24w detects an overcurrent in step S160 (indicating that the W-phase is an overcurrent phase), the offset value Iwos of the W-phase phase current Iw is calculated (step S190), and the sign of the calculated offset value Iwos is checked (step S192). Here, the sign of the offset value Iwos is the same as in Figures 4(A) and 4(B). Therefore, if the sign of the offset value Iwos is determined to be negative, it is determined that the second upper arm of the W-phase (transistor T23) is short-circuited (step S194), and this routine is terminated. On the other hand, if the sign of the offset value Iwos is determined to be positive, it is determined that the second lower arm of the W-phase (transistor T26) is short-circuited (step S196), and this routine is terminated. In this way, it is possible to determine whether the short-circuit is in the second upper arm or the second lower arm of the W-phase. This short-circuit fault detection routine shown in Figure 2 can identify the transistor with a short-circuit fault among transistors T11-T16 and T21-T26 of the first and second inverters 22 and 24.

[0027] Next, we will explain the operation of the ECU 50 when it detects a short-circuit abnormality in any of the transistors T11-T16 or T21-T26 of the first and second inverters 22 and 24. Figure 5 is a flowchart showing an example of a retraction travel control routine executed by the ECU 50. This routine is executed when the ECU 50 detects a short-circuit abnormality in any of the transistors T11-T16 or T21-T26 of the first and second inverters 22 and 24.

[0028] When this routine is executed, the ECU 50 determines which of the transistors T11-T16 and T21-T26 of the first and second inverters 22 and 24 has been detected as a short-circuit abnormality (step S200). If it determines that a short-circuit abnormality has been detected in any of the first upper arms of the three phases (transistors T11-T13), it starts the first retraction travel control (step S210) and terminates this routine. Figure 6 is an explanatory diagram showing an example of the first retraction travel control. As shown in the figure, in the first retraction travel control, the third, fourth, and fifth switches SW3, SW4, and SW5 are turned ON, the first, second, and sixth switches SW1, SW2, and SW6 are turned OFF, the first upper arms of the three phases (including the transistor with the short-circuit abnormality) are turned ON, the first lower arms of the three phases are turned OFF, and transistors T21-T26 of the second inverter 24 are switched. By turning on the third, fourth, and fifth switches SW3, SW4, and SW5, and turning off the first, second, and sixth switches SW1, SW2, and SW6, the voltage of the battery 12 is applied only to the second inverter 24 of the first and second inverters 22 and 24 (see the thick solid line in Figure 6). Also, by turning on the first upper arm of the three phases and turning off the first lower arm of the three phases, the first inverter 22 side of the three-phase coil of the motor 20 is made into a neutral point (see the thick dashed line in Figure 6). Hereinafter, the process of forming the neutral point of the motor 20 with one of the first and second inverters 22 and 24 and driving the motor 20 by switching the other is called "Y drive". In the event of a short circuit abnormality in any of the first upper arms of the three phases, the motor can be moved into an emergency position by the Y drive of the first emergency movement control.

[0029] If it is determined in step S200 that a short-circuit abnormality has been detected in any of the 3-phase first lower arms (transistors T14 to T16), the second retraction travel control is started (step S220) and this routine is terminated. In the second retraction travel control, the 1st, 2nd, and 6th switches SW1, SW2, SW6 are turned ON, the 3rd, 4th, and 5th switches SW3, SW4, SW5 are turned OFF, the 3-phase first lower arm (including the transistor with the short-circuit abnormality) is turned ON, the 3-phase first upper arm is turned OFF, and transistors T21 to T26 of the second inverter 24 are switched. By turning ON the 1st, 2nd, and 6th switches SW1, SW2, SW6 and turning OFF the 3rd, 4th, and 5th switches SW3, SW4, SW5, the voltage of the battery 12 is applied only to the second inverter 24 of the first and second inverters 22 and 24. Furthermore, by turning on the first lower arm of the three phases and turning off the first upper arm of the three phases, the first inverter 22 side of the three-phase coil of the motor 20 is neutralized. In the event of a short circuit abnormality in any of the first lower arms of the three phases, the motor can be moved to a retracted position by the Y drive of the second retracted travel control.

[0030] If it is determined in step S200 that a short-circuit abnormality has been detected in any of the 3-phase 2nd upper arms (transistors T21 to T23), the 3rd retraction travel control is started (step S230) and this routine is terminated. In the 3rd retraction travel control, the 1st, 3rd, and 4th switches SW1, SW3, SW4 are turned ON, the 2nd, 5th, and 6th switches SW2, SW5, SW6 are turned OFF, the 3-phase 2nd upper arms (including the transistor with the short-circuit abnormality) are turned ON, the 3-phase 2nd lower arms are turned OFF, and transistors T11 to T16 of the 1st inverter 22 are switched. By turning ON the 1st, 3rd, and 4th switches SW1, SW3, SW4 and turning OFF the 2nd, 5th, and 6th switches SW2, SW5, SW6, the voltage of the battery 12 is applied only to the 1st inverter 22. Furthermore, by turning on the second upper arm of the three phases and turning off the second lower arm of the three phases, the second inverter 24 side of the three-phase coil of the motor 20 is neutralized. In the event of a short circuit abnormality in any of the second upper arms of the three phases, the motor can be moved into an emergency position by the Y drive of the third emergency movement control.

[0031] If it is determined in step S200 that a short-circuit abnormality has been detected in any of the 3-phase 2nd lower arms (transistors T24 to T26), the 4th retraction travel control is started (step S240) and this routine is terminated. In the 4th retraction travel control, the 1st, 2nd, and 3rd switches SW1, SW2, SW3 are turned ON, while the 4th, 5th, and 6th switches SW4, SW5, SW6 are turned OFF, while the 3-phase 2nd lower arms (including the transistor with the short-circuit abnormality) are turned ON, while the 3-phase 2nd upper arms are turned OFF, and transistors T11 to T16 of the 1st inverter 22 are switched. By turning ON the 1st, 2nd, and 3rd switches SW1, SW2, SW3 and turning OFF the 4th, 5th, and 6th switches SW4, SW5, SW6, the voltage of the battery 12 is applied only to the 1st inverter 22. Furthermore, by turning on the second lower arm of the three phases and turning off the second upper arm of the three phases, the second inverter 24 side of the three-phase coil of the motor 20 is neutralized. In the event of a short circuit in any of the second lower arms of the three phases, the motor can be moved into an emergency position by the Y drive of the fourth emergency movement control.

[0032] In the electric vehicle 10 of the embodiment described above, when an overcurrent is detected in any phase of the first inverter 22, the first and second inverters 22 and 24 are shut down, and it is determined which of the first upper arm and the first lower arm of the overcurrent phase (first overcurrent phase) of the first inverter 22 is short-circuited based on the sign of the current offset value of the overcurrent phase (first overcurrent phase) of the first inverter 22. Similarly, when an overcurrent is detected in any phase of the second inverter 24, the first and second inverters 22 and 24 are shut down, and it is determined which of the second upper arm and the second lower arm of the second overcurrent phase is short-circuited based on the sign of the current offset value of the overcurrent phase (second overcurrent phase) of the second inverter 24. In this way, it is possible to determine which of the upper arm and lower arm of the first or second overcurrent phase is short-circuited, that is, the transistor with the short-circuit problem can be identified.

[0033] In the embodiment described above, the third, fourth, and fifth switches SW3, SW4, and SW5 are turned ON while the first, second, and sixth switches SW1, SW2, and SW6 are turned OFF during the first retraction travel control. However, the fifth and sixth switches SW5 and SW6 may be turned ON while the first, second, third, and fourth switches SW1, SW2, SW3, and SW4 are turned OFF.

[0034] In the embodiment described above, the second retraction travel control was performed by turning on the first, second, and sixth switches SW1, SW2, and SW6, and turning off the third, fourth, and fifth switches SW3, SW4, and SW5. However, the fifth and sixth switches SW5 and SW6 may be turned on, while the first, second, third, and fourth switches SW1, SW2, SW3, and SW4 may be turned off.

[0035] In the above-described embodiment, the third retraction travel control was configured to turn on the first, third, and fourth switches SW1, SW3, and SW4 while turning off the second, fifth, and sixth switches SW2, SW5, and SW6. However, the first, third, and sixth switches SW1, SW3, and SW6 may be turned on while the second, fourth, and fifth switches SW2, SW4, and SW5 may be turned off, or the first and third switches SW1, SW3 may be turned on while the second, fourth, fifth, and sixth switches SW2, SW4, SW5, and SW6 may be turned off.

[0036] In the embodiment described above, in the fourth retraction travel control, the first, second, and third switches SW1, SW2, and SW3 are turned ON, while the fourth, fifth, and sixth switches SW4, SW5, and SW6 are turned OFF. However, the first, third, and fifth switches SW1, SW3, and SW5 may be turned ON, while the second, fourth, and sixth switches SW2, SW4, and SW6 may be turned OFF, or the first and third switches SW1 and SW3 may be turned ON, while the second, fourth, fifth, and sixth switches SW2, SW4, SW5, and SW6 may be turned OFF.

[0037] In the embodiment described above, when a short-circuit abnormality is detected in any of the transistors T11-T16 or T21-T26 of the first and second inverters 22 and 24, one of the first to fourth retraction control methods is executed. However, only some of these methods may be executed, or none of them may be executed at all.

[0038] In the embodiment described above, the electric vehicle 10 is provided with a second positive electrode line 17p and a fifth switch SW5, and a second negative electrode line 17n and a sixth switch SW6, but it is not limited to this. For example, it may not be provided with the second positive electrode line 17p and the fifth switch SW5, and the second negative electrode line 17n and the sixth switch SW6.

[0039] In the embodiment described above, the configuration is that of an electric vehicle 10, but it is not limited to this. For example, it may be a hybrid vehicle configuration that further includes an engine in addition to the same hardware configuration as the electric vehicle 10, or a fuel cell vehicle configuration that further includes a fuel cell in addition to the same hardware configuration as the electric vehicle 10.

[0040] The above describes the forms for implementing this disclosure using embodiments, but this disclosure is not limited in any way to these embodiments, and can of course be implemented in various forms without departing from the gist of this disclosure. [Industrial applicability]

[0041] This disclosure can be used in industries such as electric vehicle manufacturing. [Explanation of Symbols]

[0042] 10 Electric vehicle, 12 Battery, 20 Motor, 22, 24 First and second inverters, 50 ECU, D11~D16, D21~D26 Diodes, SW1~SW6 First to sixth switches, T11~T16, T21~T26 Transistors.

Claims

1. Energy storage device, A motor having a three-phase open winding, A first inverter is connected to the first positive electrode line and the first negative electrode line to which the energy storage device is connected, and is also connected to one end of the three-phase open winding, and has a three-phase first upper arm and a three-phase first lower arm. A second inverter is connected to the first inverter on the opposite side from the energy storage device, to the first positive line and the first negative line, and is also connected to the other end of the three-phase open winding, and has a three-phase second upper arm and a three-phase second lower arm. Control device and An electric vehicle equipped with, The control device is If an overcurrent is detected in any phase of the first inverter, the shutdown process for the first and second inverters is executed, and it is determined which of the first upper arm and the first lower arm of the first overcurrent phase is short-circuited based on the sign of the current offset value of the first overcurrent phase, which is the phase of the overcurrent in the first inverter. If an overcurrent is detected in any phase of the second inverter, the shutdown process for the first and second inverters is executed, and it is determined whether the second upper arm or the second lower arm of the second overcurrent phase is short-circuited based on the sign of the current offset value of the second overcurrent phase, which is the phase of the overcurrent in the second inverter. Electric car.

2. The electric vehicle according to claim 1, A first switch is provided between the energy storage device and the first inverter on the first positive electrode line, A second switch is provided between the first and second inverters of the first positive electrode line, A third switch is provided between the energy storage device and the first inverter in the first negative electrode line, A fourth switch is provided between the first and second inverters of the first negative electrode line, A fifth switch is provided on the second positive electrode line, which connects the first positive electrode line to the energy storage device side of the first switch and to the second inverter side of the second switch, A sixth switch is provided on the second negative electrode line, which connects the first negative electrode line to the energy storage device side of the third switch and to the second inverter side of the fourth switch, Furthermore, The control device is If a short-circuit abnormality is detected in any of the three phases of the first upper arm, the third, fourth, and fifth switches are turned ON, or the fifth and sixth switches are turned ON, the first upper arm of the three phases is turned ON, and the second inverter is switched on. If a short-circuit abnormality is detected in any of the three phases of the first lower arm, the first, second, and sixth switches are turned ON, or the fifth and sixth switches are turned ON, the first lower arm of the three phases is turned ON, and the second inverter is switched on. If a short-circuit abnormality is detected in any of the three phases of the second upper arm, the first, third, and fourth switches are turned ON, or the first, third, and sixth switches are turned ON, or the first and third switches are turned ON, the second upper arm of the three phases is turned ON, and the first inverter is switched on. If a short-circuit abnormality is detected in any of the three phases of the second lower arm, the first, second, and third switches are turned ON, or the first, third, and fifth switches are turned ON, or the first and third switches are turned ON, the second lower arm of the three phases is turned ON, and the first inverter is switched on. Electric car.

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