Inverter system

Abstract

This invention provides an inverter system that can improve the vehicle's ability to move during emergency maneuvers. [Solution] The inverter system comprises an inverter that converts a DC voltage into three different voltage levels to output three-phase AC power, and a control device that controls the inverter. The inverter includes a first inverter element provided between the connection point of the first capacitor in the high-potential wiring and the connection points of the three upper-arm elements. The control device controls the first inverter element to interrupt the connection between the connection point of the first capacitor in the high-potential wiring and the connection points of the three upper-arm elements when it is determined that at least one of the three upper-arm elements is short-circuited.

Description

[Technical Field]

[0001] The present disclosure relates to an inverter system mounted on a vehicle. [Background Art]

[0002] As an inverter mounted on a vehicle, a three-level inverter that converts direct-current power output from a battery into three-phase alternating-current power is known (see, for example, Patent Document 1). [Prior Art Documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Unexamined Patent Publication No. 2024-101332 [Summary of the Invention] [Problem to be Solved by the Invention]

[0004] An object of the present disclosure is to provide an inverter system capable of improving the limp-home performance of a vehicle. [Means for Solving the Problem]

[0005] A first aspect of the present disclosure is an inverter that converts a direct current voltage into three different levels of voltage and outputs three-phase alternating current power; a control device that controls the inverter; An inverter system comprising: the inverter includes a high-potential wiring connected to a positive electrode of a power supply; a low-potential wiring connected to a negative electrode of the power supply; at least one neutral point that is a potential between the high-potential wiring and the low-potential wiring; a first capacitor connected between the high-potential wiring and the neutral point; a second capacitor connected between the neutral point and the low-potential wiring; Three upper arm elements corresponding to each of the three phases, Three lower arm elements corresponding to each of the three phases, Three middle elements corresponding to each of the three phases, A first switching element is provided between the connection position of the first capacitor in the high-potential wiring and the connection positions of the three upper arm elements, and switches between conducting and disconnecting the high-potential wiring. Equipped with, The control device is To determine whether at least one of the three upper arm elements is faulty, In response to the determination that at least one of the three upper arm elements is faulty, the all-in-one element is controlled to interrupt the high-potential wiring, Configured to perform, It is an inverter system.

[0006] A second aspect of this disclosure is, An inverter that converts DC voltage into three different voltage levels to output three-phase AC power, A control device for controlling the inverter, An inverter system comprising, The aforementioned inverter is A high-potential wire connected to the positive terminal of the power supply, A low-potential wiring connected to the negative terminal of the aforementioned power supply, At least one neutral point that is at the potential between the high-potential wiring and the low-potential wiring, A first capacitor connected between the high-potential wiring and the neutral point, A second capacitor connected between the neutral point and the low-potential wiring, Three upper arm elements corresponding to each of the three phases, Three lower arm elements corresponding to each of the three phases, Three middle elements corresponding to each of the three phases, A second switching element is provided between the connection position of the second capacitor in the low-potential wiring and the connection positions of the three lower arm elements, and switches between conducting and disconnecting the low-potential wiring. comprising: the control device is configured to: determine whether at least one of the three lower arm elements has failed; and , in response to a determination that at least one of the three lower arm elements has failed, control the second switching element to cut off the low-potential wiring; wherein the control device is configured to execute said steps which is an inverter system. Effects of the Invention

[0007] According to the present disclosure, an inverter system capable of improving the limp-home performance of a vehicle can be provided. Brief Description of the Drawings

[0008] [Figure 1] FIG. 1 is a diagram schematically illustrating an example of a schematic configuration of an inverter system according to an embodiment. [Figure 2] FIG. 2 is a diagram illustrating an example of a circuit configuration of an inverter according to an embodiment. [Figure 3] FIG. 3 is a block diagram schematically illustrating an example of a hardware configuration of an inverter system according to an embodiment. [Figure 4] FIG. 4 is a diagram for explaining the operation of a first switch when an upper arm element experiences a short-circuit failure in an embodiment. [Figure 5] FIG. 5 is a diagram for explaining the operation of a second switch when a lower arm element experiences a short-circuit failure in an embodiment. [Figure 6] FIG. 6 is a flowchart illustrating an example of a processing routine executed by an ECU in an embodiment. Modes for Carrying Out the Invention

[0009] Three-phase, three-level inverters are known as inverters installed in vehicles such as BEVs, HEVs, and PHEVs. In such inverters, if the upper arm element or the lower arm element short-circuits, the middle element also short-circuits when it is turned on. As a result, the inverter is unable to perform operations using the middle element, in addition to operations using the faulty upper or lower arm element. Consequently, there is a problem in that the vehicle's ability to maneuver in tight spaces is reduced. This disclosure solves this problem.

[0010] A first aspect of this disclosure is an inverter system comprising an inverter that converts a DC voltage into three different levels of voltage to output three-phase AC power, and a control device that controls the inverter. In the first aspect of this disclosure, the inverter comprises a first-generation conversion element. The switching element is provided between the connection position of the first capacitor and the connection positions of the three upper arm elements in the inverter's high-potential wiring, and is configured to switch between conducting and disconnecting the high-potential wiring. In the first embodiment of this disclosure, the control device is configured to determine whether at least one of the three upper arm elements is faulty, and to control the first switching element to disconnect the high-potential wiring in response to the determination that at least one of the three upper arm elements is faulty.

[0011] According to a first aspect of this disclosure, if at least one of the three upper arm elements experiences a short-circuit failure, the first inverter element disconnects the high-potential wiring between the first capacitor and the three upper arm elements. This prevents the middle element from short-circuiting even when it is turned on. As a result, the inverter can perform operations using the middle element in addition to operations using the lower arm element. Therefore, the vehicle's retraction driving performance can be improved.

[0012] Furthermore, a second aspect of the present disclosure is an inverter system comprising an inverter that converts a DC voltage into three different voltage levels to output three-phase AC power, and a control device that controls the inverter. In the second aspect of the present disclosure, the inverter includes a second switching element. The second switching element is provided between the connection position of a second capacitor in the low-potential wiring of the inverter and the connection positions of three lower-arm elements, and is configured to switch between conducting and interrupting the low-potential wiring. Furthermore, in the second aspect of the present disclosure, the control device is configured to determine whether at least one of the three lower-arm elements is faulty, and to control the second switching element to interrupt the low-potential wiring in response to the determination that at least one of the three lower-arm elements is faulty.

[0013] According to a second aspect of this disclosure, if at least one of the three lower arm elements experiences a short-circuit failure, the second switching element disconnects the low-potential wiring between the second capacitor and the three lower arm elements. This prevents the middle element from short-circuiting even when it is turned on. As a result, the inverter 11 can perform operations using the middle element in addition to operations using the upper arm element. Therefore, the vehicle's retraction driving performance can be improved.

[0014] <Embodiment> The following describes specific embodiments of the present invention with reference to the drawings. Unless otherwise specified, the hardware configuration, module configuration, functional configuration, etc. described in these embodiments are not intended to limit the scope of the disclosure to those specific embodiments.

[0015] (Overview of the inverter system) This embodiment describes an example of applying the inverter system according to the present disclosure to a vehicle. Figure 1 is a schematic diagram showing an example of the schematic configuration of the inverter system 1 in this embodiment. The inverter system 1 in this embodiment is mounted on a vehicle Vh1. The vehicle Vh1 may be a BEV, HEV, or PHEV. The inverter system 1 comprises a battery 10, an inverter 11, a motor 12, and an ECU 13.

[0016] Battery 10 is a secondary battery that outputs DC power and is an example of a "power source" according to this disclosure. Battery 10 may be a lithium-ion battery in one example. However, battery 10 is not limited to a lithium-ion battery and may be a nickel-metal hydride battery, a nickel-cadmium battery, or a solid-state battery, etc. Motor 12 is a three-phase AC motor that functions as the prime mover for vehicle Vh1. Inverter 11 is placed between battery 10 and motor 12 and converts the DC power output from battery 10 into three-phase AC power and supplies the converted three-phase AC power to motor 12. As a result, motor 12 drives the wheels of vehicle Vh1 and vehicle Vh1 moves. The ECU13 is a computer that controls the inverter 11 according to the operating conditions of the vehicle Vh1.

[0017] (Inverter circuit configuration) Figure 2 shows an example of the circuit configuration of the inverter 11 in this embodiment. The inverter 11 in this embodiment is a 3-level T-type inverter. As shown in Figure 2, the inverter 11 includes a high-potential wiring Hw1, a neutral point Np1, a low-potential wiring Lw1, a first capacitor 116, and a second capacitor 117. The high-potential wiring Hw1 is connected to the positive terminal of the battery 10 (power supply). The low-potential wiring Lw1 is connected to the negative terminal of the battery 10. The first capacitor 116 is connected between the high-potential wiring Hw1 and the neutral point Np1. The second capacitor 117 is connected between the neutral point Np1 and the low-potential wiring Lw1. The first capacitor 116 and the second capacitor 117 are smoothing capacitors that stabilize the voltage at the neutral point Np1 and reduce current ripple.

[0018] Furthermore, the inverter 11 in this embodiment includes a first switching element 110a, a second switching element 110b, a third switching element 111a, a fourth switching element 111b, a fifth switching element 112a, and a sixth switching element 112b. In one example, the first switching element 110a, the second switching element 110b, the third switching element 111a, the fourth switching element 111b, the fifth switching element 112a, and the sixth switching element 112b may be configured to include an IGBT and an arm element having a freewheeling diode connected in parallel with the IGBT. In the following description, the first switching element 110a, the second switching element 110b, the third switching element 111a, the fourth switching element 111b, the fifth switching element 112a, and the sixth switching element 112b may also be referred to as "switching element 1100".

[0019] The first switching element 110a and the second switching element 110b are connected in series between the high-potential wiring Hw1 and the low-potential wiring Lw1. In this configuration, the drain terminal of the first switching element 110a is connected to the high-potential wiring Hw1, and the source terminal of the second switching element 110b is connected to the low-potential wiring Lw1. The source terminal of the first switching element 110a and the drain terminal of the second switching element 110b are connected to the U-phase coil 121 of the motor 12. The first switching element 110a and the second switching element 110b are sometimes also called the U-phase upper arm element and the U-phase lower arm element, respectively.

[0020] The third switching element 111a and the fourth switching element 111b are connected in series between the high-potential wiring Hw1 and the low-potential wiring Lw1. In this configuration, the drain terminal of the third switching element 111a is connected to the high-potential wiring Hw1, and the source terminal of the fourth switching element 111b is connected to the low-potential wiring Lw1. Furthermore, the source terminal of the third switching element 111a and the drain terminal of the fourth switching element 111b are connected to the V-phase coil 122 of the motor 12. The third switching element 111a and the fourth switching element 111b are sometimes also called the V-phase upper arm element and the V-phase lower arm element, respectively.

[0021] The fifth switching element 112a and the sixth switching element 112b are connected in series between the high-potential wiring Hw1 and the low-potential wiring Lw1. In this configuration, the drain terminal of the fifth switching element 112a is connected to the high-potential wiring Hw1, and the source terminal of the sixth switching element 112b is connected to the low-potential wiring Lw1. Furthermore, the source terminal of the fifth switching element 112a and the drain terminal of the sixth switching element 112b are connected to the W-phase coil 123 of the motor 12. The fifth switching element 112a and the sixth switching element 112b are sometimes also called the W-phase upper arm element and the W-phase lower arm element, respectively.

[0022] The first switching element 110a, the third switching element 111a, and the fifth switching element 112a in this embodiment are examples of "upper arm elements" according to this disclosure. The second switching element 110b, the fourth switching element 111b, and the sixth switching element 112b in this embodiment are examples of "lower arm elements" according to this disclosure.

[0023] Furthermore, the inverter 11 in this embodiment includes a first middle element section 113, a second middle element section 114, and a third middle element section 115. Each of the first middle element section 113, the second middle element section 114, and the third middle element section 115 is configured to include two switching elements. Each of the two switching elements may be configured in the same manner as the switching element 1100 described above.

[0024] The first middle element section 113 includes two switching elements: a first U-phase middle element 113a and a second U-phase middle element 113b. The drain terminal of the first U-phase middle element 113a is connected to the neutral point Np1. The source terminal of the first U-phase middle element 113a is connected to the source terminal of the second U-phase middle element 113b. The drain terminal of the second U-phase middle element 113b is connected to the source terminal of the first switching element 110a and the drain terminal of the second switching element 110b. In other words, the drain terminal of the second U-phase middle element 113b is connected to the U-phase coil 121 of the motor 12. The first middle element section 113 is sometimes called a U-phase middle element.

[0025] The second middle element section 114 includes two switching elements: a first V-phase middle element 114a and a second V-phase middle element 114b. The drain terminal of the first V-phase middle element 114a is connected to the neutral point Np1. The source terminal of the first V-phase middle element 114a is connected to the source terminal of the second V-phase middle element 114b. The drain terminal of the second V-phase middle element 114b is connected to the source terminal of the second switching element 110b and the drain terminal of the third switching element 111a. In other words, the drain terminal of the second V-phase middle element 114b is connected to the V-phase coil 122 of the motor 12. The second middle element section 114 is sometimes called a V-phase middle element.

[0026] The third middle element section 115 includes two switching elements: a first W-phase middle element 115a and a second W-phase middle element 115b. The drain terminal of the first W-phase middle element 115a is connected to the neutral point Np1. The source terminal of the first W-phase middle element 115a is connected to the source terminal of the second W-phase middle element 115b. The drain terminal of the second W-phase middle element 115b is connected to the source terminal of the fifth switching element 112a and the drain terminal of the sixth switching element 112b. In other words, the drain terminal of the second W-phase middle element 115b is connected to the W-phase coil 123 of the motor 12. The third middle element section 115 is sometimes called a W-phase middle element.

[0027] The first middle element section 113, the second middle element section 114, and the third middle element section 115 in this embodiment are examples of "middle elements" according to the present disclosure.

[0028] The ECU 13 controls the inverter 11 according to the operating state of the motor 12. In one example, the ECU 13 is connected to the gate terminals of the 12 switching elements shown in Figure 2 (first switching element 110a, second switching element 110b, third switching element 111a, fourth switching element 111b, fifth switching element 112a, sixth switching element 112b, first U-phase middle element 113a, second U-phase middle element 113b, first V-phase middle element 114a, second V-phase middle element 114b, first W-phase middle element 115a, and second W-phase middle element 115b), and switches each switching element on and off. Specifically, the ECU 13 switches each switching element on and off according to the operating mode of the inverter 11. The operating modes of the inverter 11 include the following: This includes Mode 1, Mode 2, and Mode 3.

[0029] In the first mode, the ECU 13 controls the inverter 11 so that the upper arm elements (first switching element 110a, third switching element 111a, fifth switching element 112a) are turned on, the middle elements (first middle element section 113, second middle element section 114, third middle element section 115) are turned off, and the lower arm elements (second switching element 110b, fourth switching element 111b, sixth switching element 112b) are turned off. In this case, the coils 121-123 of the motor 12 and the high-potential wiring Hw1 of the inverter 11 are conductive.

[0030] In the second mode, the ECU 13 controls the inverter 11 so that the upper arm elements (first switching element 110a, third switching element 111a, fifth switching element 112a) are turned off, the middle elements (first middle element section 113, second middle element section 114, third middle element section 115) are turned on, and the lower arm elements (second switching element 110b, fourth switching element 111b, sixth switching element 112b) are turned off. In this case, the coils 121-123 of the motor 12 and the neutral point Np1 of the inverter 11 are connected.

[0031] In the third mode, the ECU 13 controls the inverter 11 so that the upper arm elements (first switching element 110a, third switching element 111a, fifth switching element 112a) are turned off, the middle elements (first middle element section 113, second middle element section 114, third middle element section 115) are turned off, and the lower arm elements (second switching element 110b, fourth switching element 111b, sixth switching element 112b) are turned on. In this case, the coils 121-123 of the motor 12 and the low-potential wiring Lw1 of the inverter 11 are conductive.

[0032] As described above, the ECU 13 switches the operating mode of the inverter 11, thereby supplying three-phase AC power from the inverter 11 to the motor 12.

[0033] In this embodiment, the inverter 11 includes, in addition to the components described above, a first switch 118 and a second switch 119. The first switch 118 is positioned between the connection point of the first capacitor 116 (Pu1 in Figure 2) and the connection point of the first switching element 110a (drain terminal) (Pu2 in Figure 2) in the high-potential wiring Hw1. The first switch 118 is a switch that switches between conducting and disconnecting the high-potential wiring Hw1, and is an example of the "first switching element" according to this disclosure. In one example, the first switch 118 may be a single-pole single-throw switch. In the following description, it is assumed that when the first switch 118 is ON, the high-potential wiring Hw1 is conducting, and when the first switch 118 is OFF, the high-potential wiring Hw1 is disconnected.

[0034] The second switch 119 is positioned between the connection point of the second capacitor 117 (Pl1 in Figure 2) and the connection point of the second switching element 110b (source terminal) (Pl2 in Figure 2) in the low-potential wiring Lw1. The second switch 119 is a switch that switches between conducting and disconnecting the low-potential wiring Lw1, and is an example of the "second switching element" according to this disclosure. In one example, the second switch 119 may be a single-pole single-throw switch similar to the first switch 118. In the following description, it is assumed that when the second switch 119 is ON, the low-potential wiring Lw1 is conducting, and when the second switch 119 is OFF, the low-potential wiring Lw1 is disconnected.

[0035] The first switch 118 and the second switch 119 described above are controlled by the ECU 13. The control of the first switch 118 and the second switch 119 will be described later.

[0036] (Hardware configuration of the inverter system) Figure 3 is a schematic block diagram showing an example of the hardware configuration of the inverter system 1. In this embodiment, the inverter system 1 includes an inverter 11, a current sensor 20, and an ECU 13. The inverter 11, current sensor 20, and ECU 13 are connected to each other by an in-vehicle network. The in-vehicle network is based on standards such as CAN (Controller Area Network), LIN (Local Interconnect Network), or FlexRay. A network would be fine.

[0037] The inverter 11 includes switching elements 1100 (first switching element 110a, second switching element 110b, third switching element 111a, fourth switching element 111b, fifth switching element 112a, sixth switching element 112b), first middle element section 113 (first U-phase middle element 113a, second U-phase middle element 113b), second middle element section 114 (first V-phase middle element 114a, second V-phase middle element 114b), third middle element section 115 (first W-phase middle element 115a, second W-phase middle element 115b), first switch 118, and second switch 119. The functions of these switching elements 1100, first middle element section 113, second middle element section 114, and third middle element section 115 are as described above.

[0038] The current sensor 20 detects the current value flowing through each of the six switching elements included in the switching element 1100. More specifically, the current sensor 20 is comprised of a first current sensor 210a that detects the current value flowing through the first switching element 110a, a second current sensor 210b that detects the current value flowing through the second switching element 110b, a third current sensor 211a that detects the current value flowing through the third switching element 111a, a fourth current sensor 211b that detects the current value flowing through the fourth switching element 111b, a fifth current sensor 212a that detects the current value flowing through the fifth switching element 112a, and a sixth current sensor 212b that detects the current value flowing through the sixth switching element 112b.

[0039] The ECU13 can be configured as a computer having a processor (CPU, GPU, etc.), main memory (RAM, ROM, etc.), and auxiliary memory (EPROM, hard disk drive, removable media, etc.). The auxiliary memory stores an operating system (OS), various programs, and various tables, and the processor executes the programs stored therein to realize the various functions of the ECU13, as described later. However, some or all of the functions may be realized as hardware modules by hardware circuits such as ASICs and FPGAs. The ECU13 in this embodiment is an example of a "control device" according to this disclosure.

[0040] The ECU 13 of this embodiment includes a control unit 130 and a storage unit 131. The control unit 130 is a processing unit that realizes various functions of the ECU 13 by executing a predetermined program stored in an auxiliary storage device. The control unit 130 can be implemented by a hardware processor such as a CPU. The control unit 130 may also be configured to include RAM, ROM, cache memory, etc. The functions realized by the control unit 130 will be described later.

[0041] The memory unit 131 is a unit that stores various types of information and is composed of storage media such as RAM, magnetic disks, and flash memory. The memory unit 131 stores predetermined programs executed by the control unit 130, data used by said programs, and so on.

[0042] Furthermore, the ECU13 is also connected to various sensors for acquiring sensor data used to control the inverter 11. Such sensors include, for example, a sensor for detecting the amount of accelerator pedal operation, a sensor for detecting the vehicle Vh1's driving speed, a sensor for detecting the vehicle Vh1's acceleration, a sensor for detecting the amount of brake pedal operation, and a sensor for detecting the shift position. The sensor may include a sensor for detecting the rotational speed of the motor 12, a sensor for detecting the remaining charge of the battery 10, and a sensor for detecting the temperature of the battery 10.

[0043] In the inverter system 1 configured as described above, the control unit 130 of the ECU 13 switches the operating mode of the inverter 11 according to the sensor data as described above. The operating modes of the inverter 11 include the first mode, second mode, and third mode described above.

[0044] Furthermore, in the inverter system 1 of this embodiment, the control unit 130 of the ECU 13 controls the first switch 118 to turn on when the upper arm elements (first switching element 110a, third switching element 111a, fifth switching element 112a) are functioning normally, and controls the first switch 118 to turn off when the upper arm elements are faulty. A fault in the upper arm elements here refers to a fault (short circuit fault) in which current flows to the upper arm elements even though the upper arm elements are controlled to be off.

[0045] A short-circuit failure in the upper arm element is determined according to the current values ​​detected by the first current sensor 210a, the third current sensor 211a, and the fifth current sensor 212a when the inverter 11 is operating in the second or third mode (when the upper arm element is controlled to be off). For example, when the inverter 11 is operating in the second or third mode, if at least one of the first current sensor 210a, the third current sensor 211a, and the fifth current sensor 212a detects a current value greater than a predetermined threshold (e.g., 0 amperes), the control unit 130 may determine that at least one of the three upper arm elements has a short-circuit failure.

[0046] As described above, when a short-circuit fault is detected in at least one of the three upper arm elements, the control unit 130 switches the first switch 118 from on to off, as shown in Figure 4. This prevents the middle element from short-circuiting even if it is turned on while an upper arm element is short-circuited. As a result, the inverter 11 can operate in the second and third modes.

[0047] Furthermore, in the inverter system 1 of this embodiment, the control unit 130 of the ECU 13 controls the second switch 119 to turn on when the lower arm elements (second switching element 110b, fourth switching element 111b, sixth switching element 112b) are functioning normally, and controls the second switch 119 to turn off when the lower arm elements are malfunctioning. The malfunction of the lower arm elements referred to here may be a short-circuit failure.

[0048] A short-circuit failure in the lower arm element is determined according to the current values ​​detected by the first current sensor 210a, the third current sensor 211a, and the fifth current sensor 212a when the inverter 11 is operating in the first or second mode (when the upper arm element is controlled to be off). For example, when the inverter 11 is operating in the second or third mode, if at least one of the first current sensor 210a, the third current sensor 211a, and the fifth current sensor 212a detects a current value greater than a predetermined threshold (e.g., 0 amperes), the control unit 130 may determine that at least one of the three upper arm elements has a short-circuit failure.

[0049] As described above, when a short-circuit fault is detected in at least one of the three lower arm elements, the control unit 130 switches the second switch 119 from on to off, as shown in Figure 5. This prevents the middle element from short-circuiting even if it is turned on while a lower arm element is short-circuited. As a result, the inverter 11 can operate in both the first and second modes.

[0050] (ECU operation) Here, the operation of the ECU13 in this embodiment will be explained with reference to Figure 6. Figure 6 is a flowchart showing an example of a processing routine that the ECU13 repeatedly executes at a predetermined period (for example, several hundred microseconds to several tens of milliseconds) while the vehicle Vh1 is starting up (while the inverter 11 is operating).

[0051] In the processing routine shown in Figure 6, first, the control unit 130 of the ECU 13 determines whether the inverter 11 is operating in the second mode or the third mode (step S101). If the inverter 11 is operating in the second mode or the third mode (affirmative determination in step S101), the upper arm elements (first switching element 110a, third switching element 111a, fifth switching element 112a) are controlled to the off state, making it possible to detect a short-circuit failure in the upper arm elements. Therefore, in steps S102-S103, the control unit 130 performs a determination process to determine whether the upper arm elements have a short-circuit failure.

[0052] In step S102, the control unit 130 acquires the current values ​​(detected values) flowing through the first switching element 110a, the third switching element 111a, and the fifth switching element 112a, respectively, through the first current sensor 210a, the second current sensor 210b, and the third current sensor 211a.

[0053] In step S103, the control unit 130 determines whether there is a detection value among the detection values ​​of the first current sensor 210a, the third current sensor 211a, and the fifth current sensor 212a that is greater than a predetermined threshold. If there is a detection value among the detection values ​​of the first current sensor 210a, the third current sensor 211a, and the fifth current sensor 212a that is greater than a predetermined threshold (affirmative determination in step S103), then the upper arm element among the three upper arm elements (first switching element 110a, third switching element 111a, and fifth switching element 112a) in which a detection value greater than the predetermined threshold was detected can be considered to have a short-circuit failure. On the other hand, if there is no detection value among the detection values ​​of the first current sensor 210a, the third current sensor 211a, and the fifth current sensor 212a that is greater than a predetermined threshold (negative determination in step S103), then it can be considered that none of the three upper arm elements (first switching element 110a, third switching element 111a, and fifth switching element 112a) have a short-circuit failure.

[0054] If the determination in step S103 is positive, the control unit 130 proceeds to the process in step S104 and controls the first switch 118 to the OFF position. On the other hand, if the determination in step S103 is negative, the control unit 130 proceeds to the process in step S105 and controls the first switch 118 to the ON position. Once the ECU 13 has finished executing the process in step S104 or step S105, it terminates the execution of the processing routine shown in Figure 6.

[0055] Furthermore, if it is determined in step S101 that the inverter 11 is operating in the first mode (negative determination in step S101), the lower arm elements (second switching element 110b, fourth switching element 111b, sixth switching element 112b) are controlled to the off state, making it possible to detect a short-circuit failure in the lower arm elements. Therefore, in steps S106-S107, the control unit 130 performs a determination process to determine whether the lower arm elements have a short-circuit failure.

[0056] In step S106, the control unit 130 acquires the current values ​​(detected values) flowing through the second switching element 110b, the fourth switching element 111b, and the sixth switching element 112b, respectively, via the second current sensor 210b, the fourth current sensor 211b, and the sixth current sensor 212b.

[0057] In step S107, the control unit 130 determines whether there is a detection value among the second current sensor 210b, the fourth current sensor 211b, and the sixth current sensor 212b that is greater than a predetermined threshold. If there is a detection value among the second current sensor 210b, the fourth current sensor 211b, and the sixth current sensor 212b that is greater than a predetermined threshold (affirmative determination in step S107), then the lower arm element among the three lower arm elements (second switching element 110b, fourth switching element 111b, and sixth switching element 112b) in which a detection value greater than the predetermined threshold was detected can be considered to have a short-circuit failure. On the other hand, if there is no detection value among the second current sensor 210b, the fourth current sensor 211b, and the sixth current sensor 212b that is greater than a predetermined threshold (negative determination in step S107), then it can be considered that none of the three lower arm elements (second switching element 110b, fourth switching element 111b, and sixth switching element 112b) have a short-circuit failure.

[0058] If the determination in step S107 is positive, the control unit 130 proceeds to the process in step S108 and controls the second switch 119 to the OFF position. On the other hand, if the determination in step S107 is negative, the control unit 130 proceeds to the process in step S109 and controls the second switch 119 to the ON position. Once the ECU 13 has finished executing the process in step S108 or step S109, it terminates the execution of the processing routine shown in Figure 6.

[0059] (Effects and Effects of the Embodiment) In the inverter system 1 of this embodiment, if at least one of the three upper arm elements of the inverter 11 (first switching element 110a, third switching element 111a, fifth switching element 112a) short-circuits, the first switch 118 of the inverter 11 is turned off. This disconnects the connection point of the first capacitor 116 (Pu1 in Figure 2) and the connection point of the first switching element 110a (drain terminal) (Pu2 in Figure 2) in the high-potential wiring Hw1. As a result, even if the middle elements of the inverter 11 (first middle element section 113, second middle element section 114, third middle element section 115) are turned on, the middle elements will not short-circuit. Therefore, if at least one of the three upper arm elements short-circuits, the inverter 11 can operate in the second and third modes.

[0060] Furthermore, in the inverter system 1 of this embodiment, if at least one of the three lower arm elements of the inverter 11 (second switching element 110b, fourth switching element 111b, sixth switching element 112b) short-circuits, the second switch 119 of the inverter 11 is turned off. This disconnects the connection point of the second capacitor 117 in the low-potential wiring Lw1 (Pl1 in Figure 2) and the connection point of the second switching element 110b (source terminal) (Pl2 in Figure 2). As a result, even if the middle elements of the inverter 11 (first middle element section 113, second middle element section 114, third middle element section 115) are turned on, the middle elements will not short-circuit. Therefore, if at least one of the three lower arm elements short-circuits, the inverter 11 can operate in both the first and second modes.

[0061] Therefore, according to the inverter system 1 of this embodiment, the vehicle Vh1's ability to move away from obstacles in the event of a short-circuit failure in the upper arm element or lower arm element of the inverter 11 can be improved.

[0062] (modified version) In the embodiment described above, an example was given in which the inverter 11 includes both the first switch 118 and the second switch 119, but the inverter 11 may be configured to include only one of the first switch 118 and the second switch 119. [Explanation of symbols]

[0063] 1...Inverter system, 10...Battery, 11...Inverter, Hw1...High potential wiring, Lw1...Low potential wiring, Np1...Neutral point, 110a...First switching element, 110b...Second switching element, 111a...Third switching element, 111b...Fourth switching element, 112a...Fifth switching element, 112b...Sixth switching element, 113...First middle element section, 114...Second middle element section, 115...Third middle element section, 116...First capacitor, 117...Second capacitor, 118...First switch, 119...Second switch, 12...Motor, 13...ECU

Claims

1. An inverter that converts DC voltage into three different voltage levels to output three-phase AC power, A control device for controlling the inverter, An inverter system comprising, The aforementioned inverter is A high-potential wire connected to the positive terminal of the power supply, A low-potential wiring connected to the negative terminal of the aforementioned power supply, At least one neutral point that is at the potential between the high-potential wiring and the low-potential wiring, A first capacitor connected between the high-potential wiring and the neutral point, A second capacitor connected between the neutral point and the low-potential wiring, Three upper arm elements corresponding to each of the three phases, Three lower arm elements corresponding to each of the three phases, Three middle elements corresponding to each of the three phases, A first switching element is provided between the connection position of the first capacitor in the high-potential wiring and the connection positions of the three upper arm elements, and switches between conducting and disconnecting the high-potential wiring. Equipped with, The control device is To determine whether at least one of the three upper arm elements is faulty, In response to the determination that at least one of the three upper arm elements is faulty, the all-in-one element is controlled to interrupt the high-potential wiring, Configured to perform, Inverter system.

2. Determining whether at least one of the three upper arm elements is faulty is: To determine whether a short-circuit current is flowing through at least one of the three upper arm elements, In response to the determination that a short-circuit current is flowing through at least one of the three upper arm elements, it is determined that at least one of the three upper arm elements is faulty. including, The inverter system according to claim 1.

3. An inverter that converts DC voltage into three different voltage levels to output three-phase AC power, A control device for controlling the inverter, An inverter system comprising, The aforementioned inverter is A high-potential wire connected to the positive terminal of the power supply, A low-potential wiring connected to the negative terminal of the aforementioned power supply, At least one neutral point that is at the potential between the high-potential wiring and the low-potential wiring, A first capacitor connected between the high-potential wiring and the neutral point, A second capacitor connected between the neutral point and the low-potential wiring, Three upper arm elements corresponding to each of the three phases, Three lower arm elements corresponding to each of the three phases, Three middle elements corresponding to each of the three phases, The connection position of the second capacitor in the low-potential wiring and the three lower arm elements A second switching element is provided between the connection point and the low-potential wiring, which switches between continuity and interruption of the low-potential wiring. Equipped with, The control device is To determine whether at least one of the three lower arm elements is faulty, In response to the determination that at least one of the three lower arm elements is faulty, the second switching element is controlled to disconnect the low-voltage wiring, Configured to perform, Inverter system.

4. Determining whether at least one of the three lower arm elements is faulty is: To determine whether a short-circuit current is flowing through at least one of the three lower arm elements, In response to the determination that a short-circuit current is flowing through at least one of the three lower arm elements, it is determined that at least one of the three upper arm elements is faulty. including, The inverter system according to claim 3.

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