electric vehicles

Abstract

When an abnormal opening of an arm in either the first or second inverter phase is detected, it becomes possible to determine whether the abnormal opening is in the upper or lower arm of that phase. [Solution] When the electric vehicle detects an abnormal opening of any phase arm of the first inverter, it determines whether the abnormal opening of the first upper arm or the first lower arm of the phase of the first inverter is due to whether all three phases of the first upper arm or the first three phases of the first lower arm can be turned on. When the electric vehicle detects an abnormal opening of any phase arm of the second inverter, it determines whether the abnormal opening of the second upper arm or the second lower arm of the phase of the second inverter is due to whether all three phases of the second upper arm or the second three phases of the second lower arm can be turned on.

Description

Technical Field

[0001] The present disclosure relates to electric vehicles.

Background Art

[0002] Conventionally, an electric vehicle has been proposed that includes a first power storage device and a second power storage device, a motor having a three-phase open winding, a first inverter connected to a first positive electrode line and a first negative electrode line to which the first power storage device is connected and also connected to one end side of the three-phase open winding and having three-phase first upper arms and three-phase first lower arms, and a second inverter connected to a second positive electrode line and a second negative electrode line to which the second power storage device is connected and also connected to the other end side of the three-phase open winding and having three-phase second upper arms and three-phase second lower arms (for example, see Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In such an electric vehicle, when detecting an open-circuit abnormality in an arm of any phase of the first inverter or the second inverter, there is a need to devise a method for determining whether the open-circuit abnormality is in the upper arm or the lower arm of that phase. The main object of the electric vehicle of the present disclosure is to be able to determine whether an open-circuit abnormality in an arm of any phase of the first inverter or the second inverter is in the upper arm or the lower arm of that phase when 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: a power storage device; a motor having a three-phase open winding; a first inverter connected to a first positive-side line and a first negative-side line to which the power 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 inverter on the opposite side from the power storage device, and connected to the first positive-side line and the first negative-side line, 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 is The gist of this method is that when an abnormal opening of an arm in any phase of the first inverter is detected, it is determined whether the abnormal opening of the first upper arm or the first lower arm of the phase of the first inverter is in the first upper arm or the first lower arm of the three phases can all be turned ON or OFF, and when an abnormal opening of an arm in any phase of the second inverter is detected, it is determined whether the abnormal opening of the second upper arm or the second lower arm of the phase of the second inverter is in the second upper arm or the second lower arm of the three phases can all be turned ON or OFF, by determining whether the abnormal opening of the phase of the second inverter is in the second upper arm or the second lower arm of the three phases. When an abnormal opening occurs in an arm in any phase of the first or second inverter, the side of the three-phase upper and lower arms that does not contain the arm with the abnormal opening can be turned ON (current corresponding to the ON state of the three phases flows), whereas the side containing the arm with the abnormal opening cannot be turned ON (current corresponding to the ON state of the three phases does not flow). Therefore, based on this, it is possible to determine whether the abnormal opening of the upper or lower arm of the phase of the malfunction is in the first upper arm or the second lower arm of the phase of the malfunction.

[0006] In the electric vehicle of this disclosure, the control device may, when it detects an overcurrent in the first inverter, identify the phase of the first inverter with an open circuit abnormality based on the cumulative value of the phase currents of each phase of the first inverter over a predetermined period, and when it detects an overcurrent in the second inverter, identify the phase of the second inverter with an open circuit abnormality based on the cumulative value of the phase currents of each phase of the second inverter over the predetermined period.

[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 an opening abnormality of any of the three phases of the first upper arm, and turns on the first, second, and sixth switches or turns on the fifth and sixth switches and the preceding If the first lower arm of the three phases is turned ON and the second inverter is switched on, and an abnormal opening of any of the first lower arms of the three phases is detected, the third, fourth, and fifth switches are turned ON, or the fifth and sixth switches are turned ON and the first upper arm of the three phases is turned ON and the second inverter is switched on, and if an abnormal opening of any of the second upper arms of the three phases is detected, the first and third switches are turned ON, or the first, second, and third switches are turned ON, or the first, third, and fifth switches are turned ON and the second lower arm of the three phases is turned ON and the first inverter is switched on, and if an abnormal opening of any of the second lower arms of the three phases is detected, the first and third switches are turned ON, or the first, third, and fourth switches are turned ON, or the first, third, and sixth switches are turned ON and the second upper arm of the three phases is turned ON and the first inverter is switched on. [Brief explanation of the drawing]

[0008] [Figure 1] This is a schematic diagram of the electric vehicle 10 according to the embodiment of the disclosure. [Figure 2]This is a flowchart showing an example of an open-circuit anomaly detection routine. [Figure 3] This is an explanatory diagram illustrating an example of what happens when an opening abnormality occurs in the first upper arm of the U phase of the first inverter during H drive. [Figure 4] This is a flowchart showing an example of a control routine for evasive maneuvers. [Figure 5] This is an explanatory diagram showing an example of the first evasive driving control procedure. [Figure 6] This is an explanatory diagram showing an example of the third-stage evasive driving control. [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 an overcurrent detection circuit 22oc that detects an overcurrent in any of the U-phase, V-phase, and W-phase lines 21u, 21v, and 21w. The second inverter 24 further includes an overcurrent detection circuit 24oc that detects an overcurrent in any of the U-phase, V-phase, or W-phase lines 23u, 23v, or 23w. The overcurrent detection circuits 22oc and 24oc are designed so that if an overcurrent is detected in one, it will not be detected in the other, 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 logic ICs. Signals from various sensors are input to the ECU50. For example, the ECU50 receives the voltage Vb of battery 12 from the voltage sensor 12v, the current Ib of battery 12 from the current sensor 12i, and the temperature Tb of battery 12 from the temperature sensor 12t. The ECU50 also receives the rotational position θm of the rotor of motor 20 from the rotational position sensor 20a, and the phase currents Iu, Iv, Iw of the U, V, and W phases of motor 20 from current sensors 20u, 20v, and 20w (when the direction of motor 20 from the first inverter 22 is positive). The ECU50 also receives signals from overcurrent detection circuits 22oc and 24oc, and the voltage VH of capacitor 30 from the voltage sensor 30v. The ECU50 also receives inputs from the power switch (on / off signal), the shift position SP (shift lever operation position from the shift position sensor), the accelerator pedal position Acc (accelerator pedal depression amount from the accelerator pedal position sensor), the brake pedal position BP (brake pedal depression amount from the brake pedal position sensor), and the vehicle speed V (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, T21~T26 of the first and second 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. The ECU 50 also calculates the electrical angle θe and rotational speed Nm of the motor 20 based on the rotational position θm of the rotor of the motor 20. The ECU 50 also calculates the waveform center deviation (deviation relative to a value of 0) ΔIu, ΔIv, ΔIw as the integrated value of the phase currents Iu, Iv, Iw of each phase of the motor 20 over a predetermined period (for example, a period corresponding to one cycle of the electrical angle θe 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 an open 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 showing an example of an open circuit abnormality element detection routine executed by the ECU 50. This routine is executed when the ECU 50 detects an overcurrent in one of the first and second inverters 22 and 24 based on signals from the overcurrent detection circuits 22oc and 24oc. Note that if an open circuit abnormality occurs in any of the transistors T11-T16 or T21-T26, an overcurrent may occur in one of the first and second inverters 22 and 24 due to disturbances in motor control, etc. Furthermore, when the ECU 50 detects an overcurrent in either the first or second inverter 22 or 24, it executes a shutdown process for the first or second inverter 22 or 24, that is, it controls the first or second inverter 22 or 24 so that all transistors T11-T16 and T21-T26 are turned off.

[0017] When this routine is executed, the ECU 50 first determines which of the first and second inverters 22 and 24 (overcurrent detection circuits 22oc and 24oc) has detected an overcurrent (step S100). If it is determined that an overcurrent has been detected in the first inverter 22, the ECU 50 uses the waveform center deviations ΔIu, ΔIv, and ΔIw of each phase immediately before the shutdown process of the first and second inverters 22 and 24 to identify the phase with the open circuit abnormality among the phases of the first inverter 22 (step S110), and determines whether the phase with the open circuit abnormality is the U phase, V phase, or W phase (step S112). Figure 3 is an explanatory diagram showing an example of what happens when an open circuit abnormality occurs in the first upper arm (transistor T11) of the U phase of the first inverter 22 while driving in H drive mode. When all transistors T11-T16 and T21-T26 of the first and second inverters 22 and 24 are functioning normally, the waveform center deviations ΔIu, ΔIv, and ΔIw for each phase are approximately 0. In contrast, if an open circuit anomaly occurs in the first upper arm of the U phase of the first inverter 22, the phase current Iu of the U phase will have a waveform as shown in Figure 3, and the waveform center deviation ΔIu of the U phase will have a relatively large absolute value. Therefore, for example, the phase with the open circuit anomaly can be identified by comparing the absolute values ​​of the waveform center deviations ΔIu, ΔIv, and ΔIw with a threshold value.

[0018] If it is determined in step S112 that the phase with the open circuit abnormality is the U phase, after the shutdown process of the first and second inverters 22 and 24 is executed, the ON process for the 3-phase first lower arm is executed (step S120), and it is determined whether all of the 3-phase first lower arm can be turned ON (step S122). Here, in the ON process for the 3-phase first lower arm, the first inverter 22 is controlled so that all transistors T11 to T13 are in the OFF state and all transistors T14 to T16 are in the ON state. When the ON process for the 3-phase first lower arm is executed while the motor 20 is rotating, a current based on the back electromotive force generated with the rotation of the motor 20 flows through each phase of the motor 20. At this time, the waveforms of the phase currents Iu, Iv, Iw and the waveform center deviations ΔIu, ΔIv, ΔIw of each phase differ depending on whether all of the 3-phase first lower arm can be turned ON or not. The inventors confirmed this through experiments and analyses. Therefore, these can be used to determine whether or not all of the first lower arms of the three phases were able to be turned on. If it is determined that all of the first lower arms of the three phases were able to be turned on, it is determined that the first upper arm of the U phase (transistor T11) has an open circuit abnormality (step S124), and this routine is terminated. On the other hand, if it is determined that some of the first lower arms of the three phases could not be turned on, it is determined that the first lower arm of the U phase (transistor T14) has an open circuit abnormality (step S126), and this routine is terminated. In this way, it is possible to determine whether the open circuit abnormality is in the first upper arm or the first lower arm of the U phase.

[0019] Even when it is determined in step S112 that the phase with an open-circuit abnormality is the V phase, after executing the shutdown process of the first and second inverters 22 and 24, the ON process of the first lower arms of the three phases is executed (step S130), and it is determined whether all of the first lower arms of the three phases can be turned on (step S132). When it is determined that all of the first lower arms of the three phases can be turned on, it is determined that the first upper arm (transistor T12) of the V phase has an open-circuit abnormality (step S134), and this routine ends. On the other hand, when it is determined that a part of the first lower arms of the three phases cannot be turned on, it is determined that the first lower arm (transistor T15) of the V phase has an open-circuit abnormality (step S136), and this routine ends. In this way, it is possible to determine which of the first upper arm and the first lower arm of the V phase has an open-circuit abnormality.

[0020] Even when it is determined in step S112 that the phase with an open-circuit abnormality is the W phase, after executing the shutdown process of the first and second inverters 22 and 24, the ON process of the first lower arms of the three phases is executed (step S140), and it is determined whether all of the first lower arms of the three phases can be turned on (step S142). When it is determined that all of the first lower arms of the three phases can be turned on, it is determined that the first upper arm (transistor T13) of the W phase has an open-circuit abnormality (step S144), and this routine ends. On the other hand, when it is determined that a part of the first lower arms of the three phases cannot be turned on, it is determined that the first lower arm (transistor T16) of the W phase has an open-circuit abnormality (step S146), and this routine ends. In this way, it is possible to determine which of the first upper arm and the first lower arm of the W phase has an open-circuit abnormality.

[0021] When it is determined in step S100 that an overcurrent has been detected by the second inverter 24, similar to the process of step S110, the phase center deviation ΔIu, ΔIv, ΔIw of each phase immediately before executing the shutdown process of the first and second inverters 22 and 24 is used to identify the phase with an open-circuit abnormality among each phase of the second inverter 24 (step S150), and it is determined whether the phase with the open-circuit abnormality is the U phase, V phase, or W phase (step S152). When it is determined in step S152 that the phase with the open-circuit abnormality is the U phase, after executing the shutdown process of the first and second inverters 22 and 24, the on process of the three-phase second lower arms is executed (step S160), and it is determined whether all of the three-phase second lower arms have been turned on (step S162). Here, in the on process of the three-phase second lower arms, the second inverter 24 is controlled such that all of the transistors T21 to T23 are in the off state and all of the transistors T24 to T26 are in the on state. When it is determined that all of the three-phase second lower arms have been turned on, it is determined that the second upper arm (transistor T21) of the U phase has an open-circuit abnormality (step S164), and this routine ends. On the other hand, when it is determined that a part of the three-phase second lower arms cannot be turned on, it is determined that the second lower arm (transistor T24) of the U phase has an open-circuit abnormality (step S166), and this routine ends. In this way, it is possible to discriminate whether the open-circuit abnormality is in the second upper arm or the second lower arm of the U phase.

[0022] Even when it is determined in step S152 that the phase with the open circuit abnormality is the V phase, after executing the shutdown process for the first and second inverters 22 and 24, the ON process for the second lower arm of the 3 phase is executed (step S170), and it is determined whether all of the second lower arms of the 3 phase were able to be turned ON (step S172). If it is determined that all of the second lower arms of the 3 phase were able to be turned ON, it is determined that the second upper arm of the V phase (transistor T22) has an open circuit abnormality (step S174), and this routine is terminated. On the other hand, if it is determined that it was not possible to turn on some of the second lower arms of the 3 phase, it is determined that the second lower arm of the V phase (transistor T25) has an open circuit abnormality (step S176), and this routine is terminated. In this way, it is possible to determine whether the open circuit abnormality is in the second upper arm or the second lower arm of the V phase.

[0023] Even when it is determined in step S152 that the phase with the open circuit abnormality is the W phase, after executing the shutdown process for the first and second inverters 22 and 24, the ON process for the second lower arm of the 3 phase is executed (step S180), and it is determined whether all of the second lower arms of the 3 phase were able to be turned ON (step S182). If it is determined that all of the second lower arms of the 3 phase were able to be turned ON, it is determined that the second upper arm of the W phase (transistor T23) has an open circuit abnormality (step S184), and this routine is terminated. On the other hand, if it is determined that it was not possible to turn on some of the second lower arms of the 3 phase, it is determined that the second lower arm of the W phase (transistor T26) has an open circuit abnormality (step S186), and this routine is terminated. In this way, it is possible to determine whether the open circuit abnormality is in the second upper arm or the second lower arm of the W phase.

[0024] Next, we will explain the operation of the ECU 50 when it detects an open circuit abnormality in any of the transistors T11 to T16 of the first and second inverters 22 and 24. Figure 4 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 an open circuit abnormality in any of the transistors T11 to T16 or T21 to T26 of the first and second inverters 22 and 24.

[0025] 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 detected an open circuit abnormality (step S200). If it determines that an open 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 5 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 first, second, and sixth switches SW1, SW2, and SW6 are turned ON, the third, fourth, and fifth switches SW3, SW4, and SW5 are turned OFF, the first upper arms of the three phases (including the transistor with the open circuit abnormality) are turned OFF, the first lower arms of the three phases are turned ON, and transistors T21-T26 of the second inverter 24 are switched. 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, 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 5). Also, by turning off the first upper arm of the three phases and turning on 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 5). 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". When there is an opening abnormality in any of the first upper arms of the three phases, the motor can move in the retraction mode by the Y drive of the first retraction control.

[0026] If it is determined in step S200 that an open circuit abnormality has been detected in any of the 3-phase 1st lower arms (transistors T14~T16), the 2nd retraction travel control is started (step S210) and this routine is terminated. In the 2nd retraction travel control, the 3rd, 4th, and 5th switches SW3, SW4, SW5 are turned ON, the 1st, 2nd, and 6th switches SW1, SW2, SW6 are turned OFF, the 3-phase 1st upper arm is turned ON, the 3-phase 1st lower arm (including the transistor with the open circuit abnormality) is turned OFF, and transistors T21~T26 of the 2nd inverter 24 are switched. By turning ON the 3rd, 4th, and 5th switches SW3, SW4, SW5 and turning OFF the 1st, 2nd, and 6th switches SW1, SW2, SW6, the voltage of the battery 12 is applied only to the 2nd inverter 24 of the 1st and 2nd inverters 22, 24. Furthermore, 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 coils of the motor 20 is neutralized. If there is an opening abnormality in either of the first lower arms of the three phases, the vehicle can move in a retracted position by the Y drive of the second retracted travel control.

[0027] If it is determined in step S200 that an open circuit abnormality has been detected in any of the 3-phase second upper arms (transistors T21 to T23), the third retraction travel control is started (step S230) and this routine is terminated. Figure 6 is an explanatory diagram showing an example of the third retraction travel control. As shown in the figure, in the third retraction travel control, the first and third switches SW1 and SW3 are turned ON, the second, fourth, fifth and sixth switches SW2, SW4, SW5 and SW6 are turned OFF, the 3-phase second upper arms (including the transistor with the open circuit abnormality) are turned OFF, the 3-phase second lower arms are turned ON, and transistors T11 to T16 of the first inverter 22 are switched. By turning on the first and third switches SW1 and SW3, and turning off the second, fourth, fifth, and sixth switches SW2, SW4, SW5, and SW6, the voltage of the battery 12 is applied only to the first inverter 22 of the first and second inverters 22 and 24 (see the thick solid line in Figure 6). Also, by turning off the second upper arm of the three phases and turning on the second lower arm of the three phases, the second inverter 24 side of the motor 20 is neutralized (see the thick dashed line in Figure 6). If there is an opening abnormality in any of the second upper arms of the three phases, the vehicle can move in a retracted position by the Y drive of the third retracted travel control.

[0028] If it is determined in step S200 that an open 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 S230) and this routine is terminated. In the 4th retraction travel control, the 1st and 3rd switches SW1 and SW3 are turned ON, the 2nd, 4th, 5th, and 6th switches SW2, SW4, SW5, and SW6 are turned OFF, the 3-phase 2nd upper arm is turned ON, the 3-phase 2nd lower arm (including the transistor with the open circuit abnormality) is turned OFF, and transistors T11 to T16 of the 1st inverter 22 are switched. By turning ON the 1st and 3rd switches SW1 and SW3 and turning OFF the 2nd, 4th, 5th, and 6th switches SW2, SW4, SW5, and SW6, the voltage of the battery 12 is applied only to the 1st inverter 22 of the 1st and 2nd inverters 22 and 24. Furthermore, by turning on the 3-phase second upper arm and turning off the 3-phase second lower arm, the second inverter 24 side of the motor 20 is neutralized. If there is an opening abnormality in either of the 3-phase second lower arms, the vehicle can move in a retracted position by the Y drive of the fourth retracted travel control.

[0029] In the electric vehicle 10 of the embodiment described above, when an abnormal opening of any phase arm of the first inverter 22 is detected, it is determined which of the first upper or lower arms of the phase with the abnormal opening is affected by whether or not all three phases of the first lower arm can be turned ON. Similarly, when an abnormal opening of any phase arm of the second inverter 24 is detected, it is determined which of the second upper or lower arms of the phase with the abnormal opening is affected by whether or not all three phases of the second lower arm can be turned ON. In this way, it is possible to determine which of the upper or lower arms of the phase with the abnormal opening is affected. That is, the transistor with the abnormal opening can be identified.

[0030] In the embodiment described above, when an abnormal opening of an arm in any phase of the first inverter 22 is detected, it is determined whether the abnormal opening is in the first upper arm or the first lower arm of the phase with the abnormal opening by whether all three phases of the first lower arm can be turned ON. Alternatively, it may be determined whether the abnormal opening is in the first upper arm or the first lower arm of the phase with the abnormal opening by whether all three phases of the first upper arm can be turned ON. The same applies when an abnormal opening of an arm in any phase of the second inverter 24 is detected.

[0031] In the embodiment described above, the first 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.

[0032] In the embodiment described above, the second retraction travel control was performed 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. 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.

[0033] In the above-described embodiment, the third retraction travel control was configured to turn on the first and third switches SW1 and SW3 while turning off the second, fourth, fifth, and sixth switches SW2, SW4, SW5, and SW6. However, the first, second, and third switches SW1, SW2, and SW3 may be turned on while turning off the fourth, fifth, and sixth switches SW4, SW5, and SW6, or the first, third, and fifth switches SW1, SW3, and SW5 may be turned on while turning off the second, fourth, and sixth switches SW2, SW4, and SW6.

[0034] In the embodiment described above, in the fourth retraction travel control, the first and third switches SW1 and SW3 are turned ON, and the second, fourth, fifth, and sixth switches SW2, SW4, SW5, and SW6 are turned OFF. However, the first, third, and fourth switches SW1, SW3, and SW4 may be turned ON, and the second, fifth, and sixth switches SW2, SW5, and SW6 may be turned OFF, or the first, third, and sixth switches SW1, SW3, and SW6 may be turned ON, and the second, fourth, and fifth switches SW2, SW4, and SW5 may be turned OFF.

[0035] 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.

[0036] 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.

[0037] 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.

[0038] Although the embodiments for implementing this disclosure have been described above, 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]

[0039] This disclosure can be used in industries such as electric vehicle manufacturing. [Explanation of Symbols]

[0040] 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 electrode line and the first negative electrode 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 abnormal opening of any phase arm of the first inverter is detected, it is determined whether the abnormal opening of the first upper arm or the first lower arm of the phase of the first inverter can be turned ON or OFF. When an abnormal opening of an arm in any phase of the second inverter is detected, it is determined whether the abnormal opening of the second upper arm or the second lower arm of the phase of the second inverter is affected by whether all of the three phases of the second upper arm or the three phases of the second lower arm can be turned ON. Electric car.

2. The electric vehicle according to claim 1, The control device is When an overcurrent is detected in the first inverter, the phase of the first inverter with an open circuit abnormality is identified based on the cumulative value of the phase current of each phase of the first inverter over a predetermined period. When an overcurrent is detected in the second inverter, the phase of the second inverter with an open circuit abnormality is identified based on the cumulative value of the phase current of each phase of the second inverter over the predetermined period. Electric car.

3. An electric vehicle according to claim 1 or 2, 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 an abnormal opening of any of the three phases of the first upper arm is detected, 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 an abnormal opening of any of the three phases of the first lower arm is detected, 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 an abnormal opening of any of the three phases of the second upper arm is detected, the first and third switches are turned ON, or the first, second, and third switches are turned ON, or the first, third, and fifth switches are turned ON, and the second lower arm of the three phases is turned ON, and the first inverter is switched on. If an abnormal opening of any of the three phases of the second lower arm is detected, the first and third switches are turned ON, or the first, third, and fourth switches are turned ON, or the first, third, and sixth switches are turned ON, and the second upper arm of the three phases is turned ON, and the first inverter is switched on. Electric car.

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