Electric power conversion system and drive system

Abstract

To provide an electric power conversion system and a drive system capable of detecting an abnormality in an electric conduction path and a current sensor.SOLUTION: An electric power conversion circuit 4 has invertors 8, 9. The invertor 8 is connected to one end of coils 3U, 3V, 3W via an output line 13. The invertor 9 is connected to the other end of the coils 3U, 3V, 3W via the output line 13. An output current sensor 123 detects a current flowing in an output line 14 as a current flowing in the coils 3U, 3V, 3W. The output current sensor 123 is provided on the output line 14 but is not provided on the output line 13. Wiring 5A, 6A connects the invertor 8 and the invertor 9 without going through thee coils 3U, 3V, 3W. A switch current sensor 124 detects a current flowing in the wiring 5A, 6A. The switch current sensor 124 is provided on each of the wiring 5A, 6A.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] TECHNICAL FIELD The disclosure herein relates to power conversion devices and drive systems. [Background technology]

[0002] Patent Document 1 discloses a power conversion device including a first inverter connected to one end of a winding of a rotating electric machine and a second inverter connected to the other end of the winding. A current sensor is provided in the connection path connecting the first inverter and the winding. One current sensor is provided for each of the three-phase connection paths. The contents of the prior art documents are incorporated by reference as explanations of the technical elements in this specification. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2022-177342 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the above-mentioned Patent Document 1, there is a concern that even if an abnormality occurs in a current path such as a connection path or in a current sensor, the abnormality in the current path or the current sensor cannot be detected. From the above-mentioned viewpoints and other viewpoints not mentioned, further improvements are required in power conversion modules.

[0005] One disclosed object is to provide a power conversion device and a drive system that can detect abnormalities in current paths and current sensors. [Means for solving the problem]

[0006] One aspect of the disclosure is A power conversion device (4) that converts power supplied to a rotating electric machine (3), a first inverter (8) connected to one end of a winding of the rotating electric machine; a second inverter (9) connected to the other end of the winding; a winding current sensor (123) for detecting a current flowing through the winding; a direct current sensor (124) for detecting a current flowing in a direct path (5, 6) connecting the first inverter and the second inverter without passing through a winding; The power conversion device is provided with:

[0007] In the power conversion device described above, the current flowing through the windings is detected by the winding current sensor, and the current flowing through the direct path is detected by the direct current sensor. With this configuration, it is possible to determine whether an abnormality has occurred in the current path of the windings, the winding current sensor, or the direct current sensor using the detection results of the winding current sensor and the direct current sensor. Therefore, it is possible to detect an abnormality in the current path or the current sensor.

[0008] One aspect of the disclosure is A rotating electric machine (3), a power converter (4) that converts power supplied to the rotating electric machine; A drive system (1) for driving a rotating electric machine by a power conversion device, comprising: a three-phase first inverter (8) connected to one end of a winding of the rotating electric machine; a three-phase second inverter (9) connected to the other end of the winding; a winding current sensor (123) for detecting a current flowing through the winding; a direct current sensor (124) for detecting a current flowing in a direct path (5, 6) connecting the first inverter and the second inverter without passing through a winding; The drive system is provided with:

[0009] According to the drive system, similar to the power conversion device, it is possible to detect an abnormality in the current sensor.

[0010] The various aspects disclosed in this specification employ different technical means to achieve their respective objectives. The reference numerals in parentheses in the claims and in this section are intended to exemplify correspondences with the following embodiments and are not intended to limit the technical scope. The objectives, features, and advantages disclosed in this specification will become more apparent by reference to the following detailed description and the accompanying drawings. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 2 illustrates a power conversion circuit and a drive system. [Figure 2] FIG. 4 is a diagram showing an example of an operating point map of the rotating electric machine. [Figure 3] FIG. 1 is a diagram showing a star-connected drive. [Figure 4] FIG. 10 is a diagram showing an open connection drive. [Figure 5] FIG. 2 is a circuit diagram showing a state in which an external device is connected. [Figure 6] 10 is a flowchart showing the procedure of a rotation control process. [Figure 7] FIG. 10 is a diagram illustrating a reference example. [Figure 8] FIG. 10 is a diagram illustrating a reference example. [Figure 9] FIG. 10 is a diagram illustrating a power conversion circuit and a drive system according to a modified example. [Figure 10] FIG. 10 is a diagram illustrating a power conversion circuit and a drive system according to a modified example. [Figure 11] FIG. 10 is a diagram illustrating a power conversion circuit and a drive system according to a modified example. [Figure 12] FIG. 10 is a diagram illustrating a power conversion circuit and a drive system according to a modified example. [Figure 13] FIG. 10 is a diagram illustrating a power conversion circuit and a drive system according to a second embodiment. [Figure 14] FIG. 10 is a diagram illustrating a power conversion circuit and a drive system according to a third embodiment. [Figure 15] FIG. 10 is a diagram illustrating a power conversion circuit and a drive system according to a fourth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, several embodiments will be described with reference to the drawings. Note that in each embodiment, corresponding components are designated by the same reference numerals, and redundant description may be omitted. When only a portion of the configuration is described in each embodiment, the configuration of another embodiment previously described may be applied to the remaining portion of the configuration. Furthermore, in addition to the combinations of configurations explicitly stated in the description of each embodiment, configurations of several embodiments may be partially combined together even if not explicitly stated, provided that there is no particular problem with the combination.

[0013] The power conversion module of this embodiment is applied to, for example, a mobile body using a rotating electric machine as a drive source, such as an electric vehicle (BEV), a hybrid electric vehicle (HEV), a plug-in hybrid electric vehicle (PHEV), an aircraft such as an electric vertical take-off and landing aircraft or a drone, a ship, a construction machine, an agricultural machine, etc.

[0014] (First embodiment) First, the schematic configuration of a drive system for a moving body will be described with reference to FIG.

[0015] <Drive systems for moving objects> As shown in FIG. 1, a drive system 1 for a moving body includes a DC power supply 2, a rotating electric machine 3, and a power conversion circuit 4.

[0016] The DC power supply 2 may be, for example, a rechargeable secondary battery such as a lithium ion battery or a nickel-metal hydride battery. The DC power supply 2 may also be one that converts AC power to DC and outputs it. The DC power supply 2 supplies power to the rotating electrical machine 3. The DC power supply 2 corresponds to a power supply unit.

[0017] The rotating electric machine 3 is a three-phase open-winding type rotating electric machine with an open neutral point. The rotating electric machine 3 has a U-phase winding 3U, a V-phase winding 3V, and a W-phase winding 3W. Hereinafter, the U-phase winding 3U, the V-phase winding 3V, and the W-phase winding 3W may be simply referred to as windings 3U, 3V, and 3W.

[0018] The rotating electric machine 3 functions, for example, as a drive source for a moving body, that is, as an electric motor. If the moving body is a vehicle, the rotating electric machine 3 generates torque for driving drive wheels (not shown). The rotating electric machine 3 is not limited to an electric motor. The rotating electric machine 3 may be a motor generator that functions as both an electric motor and a generator, or may be a generator.

[0019] The power conversion circuit 4 converts power between the DC power source 2 and the rotating electric machine 3. The power conversion circuit 4 corresponds to a power conversion device. The power conversion circuit 4 is a three-phase power conversion device. The drive system 1 is a common power supply system in which a common DC power source 2 supplies power to two inverters 8 and 9 (described later) to drive the rotating electric machine 3. The drive system 1 may include only one common DC power source 2 as illustrated in FIG. 1, or multiple common DC power sources 2. The drive system 1 may include a power supply switch (not shown), such as an SMR, between the DC power source 2 and the power conversion circuit 4. SMR is an abbreviation for System Main Relay. Turning on the power supply switch enables power supply from the DC power source 2 to the rotating electric machine 3, and turning off the power supply switch cuts off the power supply from the DC power source 2 to the rotating electric machine 3.

[0020] <Power conversion circuit> Next, the power conversion circuit 4 will be described with reference to Fig. 1. Fig. 1 shows an example of the power conversion circuit 4. The power conversion circuit 4 shown in Fig. 1 includes power lines 5 and 6, a smoothing capacitor 7, inverters 8 and 9, a changeover switch 10, and snubber circuits 11 and 12.

[0021] The power supply line 5 is a high-potential power line. The power supply line 5 is connected to the positive electrode of the DC power supply 2. The power supply line 5 may be referred to as a positive-side power supply line, P line, etc. The power supply line 5 has a wiring 5A. The wiring 5A is a part of the wiring that constitutes the power supply line 5. The wiring 5A is a part of the power supply line 5 that connects the inverter 8 and the inverter 9. The power supply line 6 is a low-potential power line. The power supply line 6 is connected to the negative electrode of the DC power supply 2. The power supply line 6 may be referred to as a negative-side power supply line, N line, etc. The power supply line 6 has a wiring 6A. The wiring 6A is a part of the wiring that constitutes the power supply line 6. The wiring 6A is a part of the power supply line 6 that connects the inverter 8 and the inverter 9. The power supply lines 5, 6 are configured to include a bus bar that is, for example, a metal plate.

[0022] The smoothing capacitor 7 mainly smoothes the DC voltage supplied from the DC power supply 2. The smoothing capacitor 7 is provided between the power supply lines 5 and 6. The positive electrode of the smoothing capacitor 7 is connected to the power supply line 5 between the DC power supply 2 and the inverters 8 and 9. The negative electrode of the smoothing capacitor 7 is connected to the power supply line 6 between the DC power supply 2 and the inverters 8 and 9. The smoothing capacitor 7 is connected in parallel to the inverters 8 and 9.

[0023] The inverters 8 and 9 are DC-AC conversion circuits. The inverters 8 and 9 are three-phase inverter circuits. The inverter 8 corresponds to a first inverter, and the inverter 9 corresponds to a second inverter. The inverter 8 is configured with upper and lower arm circuits 8HL for three phases. The upper and lower arm circuits 8HL are sometimes referred to as legs. The upper and lower arm circuit 8HL has an upper arm 8H and a lower arm 8L. The upper arm 8H and the lower arm 8L are connected in series between the power supply lines 5 and 6, with the upper arm 8H on the power supply line 5 side.

[0024] The connection point between the upper arm 8H and the lower arm 8L is connected to the winding of the corresponding phase in the rotating electric machine 3 via an output line 13. The inverter 8 has six arms. Each arm is configured with a switching element. The number of switching elements configuring each arm is not particularly limited. There may be one or more. When there are more than one switching elements, the multiple switching elements connected in parallel to each other are turned on and off at the same timing by a common gate drive signal (drive voltage).

[0025] In the example shown in FIG. 1, an n-channel MOSFET 8S is used as the switching element constituting each arm. MOSFET is an abbreviation for Metal Oxide Semiconductor Field Effect Transistor. In the upper arm 8H, the drain terminal of the MOSFET 8S is connected to the power supply line 5. In the lower arm 8L, the source terminal of the MOSFET 8S is connected to the power supply line 6. The source terminal of the MOSFET 8S in the upper arm 8H and the drain terminal of the MOSFET 8S in the lower arm 8L are connected to each other.

[0026] A freewheeling diode 8D is connected in antiparallel to each MOSFET 8S. The diode 8D may be a parasitic diode (body diode) of the MOSFET 8S, or may be provided separately from the parasitic diode. The anode terminal of the diode 8D is connected to the source terminal of the corresponding MOSFET 8S, and the cathode terminal is connected to the drain terminal.

[0027] The inverter 9 has the same configuration as the inverter 8. The inverter 9 is configured with upper and lower arm circuits 9HL for three phases. The upper and lower arm circuit 9HL has an upper arm 9H and a lower arm 9L. The upper arm 9H and the lower arm 9L are connected in series between the power supply lines 5 and 6, with the upper arm 9H on the power supply line 5 side.

[0028] The connection point between the upper arm 9H and the lower arm 9L is connected to the winding of the corresponding phase in the rotating electric machine 3 via an output line 14. The inverter 9 also has six arms. Each arm is configured with a switching element. The number of switching elements constituting each arm is not particularly limited. It may be one or more.

[0029] In the example shown in Fig. 1, an n-channel MOSFET 9S is used as the switching element constituting each arm. In the upper arm 9H, the drain terminal of the MOSFET 9S is connected to the power supply line 5. In the lower arm 9L, the source terminal of the MOSFET 9S is connected to the power supply line 6. The source terminal of the MOSFET 9S in the upper arm 9H and the drain terminal of the MOSFET 9S in the lower arm 9L are connected to each other. A freewheeling diode 9D is connected in anti-parallel to each MOSFET 9S.

[0030] As described above, the high-potential terminals (drain terminals) of the upper arms 8H, 9H of the inverters 8, 9 are connected to the power line 5. The low-potential terminals (source terminals) of the lower arms 8L, 9L are connected to the power line 6. A node connecting the upper arm 8H and the lower arm 8L is connected to one end of the corresponding phase winding via an output line 13, and a node connecting the upper arm 9H and the lower arm 9L is connected to the other end of the corresponding phase winding via an output line 14. Specifically, one end of the U-phase winding 3U is connected to a node U1 of the U-phase upper and lower arm circuit 8HL, and the other end of the U-phase winding 3U is connected to a node U2 of the U-phase upper and lower arm circuit 9HL. One end of the V-phase winding 3V is connected to a node V1 of the V-phase upper and lower arm circuit 8HL, and the other end of the V-phase winding 3V is connected to a node V2 of the V-phase upper and lower arm circuit 9HL. One end of the W-phase winding 3W is connected to a node W1 of a W-phase upper and lower arm circuit 8HL, and the other end of the W-phase winding 3W is connected to a node W2 of a W-phase upper and lower arm circuit 9HL.

[0031] The switching elements constituting the inverters 8 and 9 are not limited to the MOSFETs described above. For example, IGBTs may be used. IGBT stands for Insulated Gate Bipolar Transistor. In the case of an IGBT, a freewheeling diode is also connected in anti-parallel.

[0032] The changeover switch 10 is a semiconductor switch. A semiconductor switch has a switching element formed on a semiconductor chip. The switching element is not particularly limited and may have the same configuration as the switching element constituting at least one of the inverters 8, 9, or may have a different configuration. The changeover switch 10 is provided between the inverters 8 and 9 on at least one of the power supply lines 5, 6. When the changeover switch 10 is closed, it connects the high-potential side terminal of the upper arm 9H of the inverter 9 to the smoothing capacitor 7 (DC power supply 2). When the changeover switch 10 is open, it cuts off the connection between the high-potential side terminal of the upper arm 9H and the smoothing capacitor 7 (DC power supply 2). The changeover switch 10 may also be called a switch or an open / close switch.

[0033] The switching element of the changeover switch 10 illustrated in FIG. 1 is a MOSFET. A diode is connected in anti-parallel to the MOSFET. The diode is, for example, a parasitic diode. The changeover switch 10 includes changeover switches 10A and 10B. The changeover switch 10A is arranged on wiring 5A of the power supply line 5. The changeover switch 10A is arranged on wiring 5A so that the drain terminal of the MOSFET is on the inverter 8 side and the source terminal is on the inverter 9 side. In other words, the changeover switch 10A is arranged so that the forward direction of the diode is from the inverter 9 to the inverter 8.

[0034] The changeover switch 10B is arranged on the wiring 6A of the power supply line 6. The changeover switch 10B is arranged on the wiring 6A so that the drain terminal of the MOSFET is on the inverter 9 side and the source terminal is on the inverter 8 side. In other words, the changeover switch 10B is arranged so that the forward direction of the diode is from the inverter 8 to the inverter 9. When the MOSFET is turned on and the changeover switch 10 is closed, the inverter 9 is electrically connected to the smoothing capacitor 7 (DC power supply 2). When the MOSFET is turned off and the changeover switch 10 is opened, the electrical connection between the inverter 9 and the smoothing capacitor 7 is interrupted.

[0035] The snubber circuit 11 is connected in parallel to the inverter 9, i.e., the upper and lower arm circuits 9HL. The snubber circuit 11 reduces the inductance of the upper and lower arm circuits 9HL. In other words, the snubber circuit 11 absorbs a transient high voltage, or so-called switching surge, that occurs when the switching elements (MOSFETs 9S) that make up the upper and lower arm circuits 9HL are switched. This enables the inverter 9 to perform high-speed switching.

[0036] The snubber circuit 11 has at least a capacitor 11C. The snubber circuit 11 may be, for example, a C snubber circuit having a capacitor, or an RC snubber circuit having a capacitor and a resistor. It may also be an RCD snubber circuit having a capacitor, a resistor, and a diode. The snubber circuit 11 shown in FIG. 1 is an RC snubber circuit in which a capacitor 11C and a resistor 11R are connected in series. One end of the snubber circuit 11 is connected to the power supply line 5. Another end of the snubber circuit 11 is connected to a portion of the wiring 5A that connects the changeover switch 10 and the inverter 9. The other end of the snubber circuit 11 is connected to the power supply line 6.

[0037] In the power conversion circuit 4 illustrated in FIG. 1, a snubber circuit 11 is provided for each phase of the upper and lower arm circuits 9HL. The power conversion circuit 4 includes three snubber circuits 11. One end of each snubber circuit 11 is connected to the power supply line 5, and the other end is connected to the power supply line 6. Each snubber circuit 11 includes a capacitor 11C and a resistor 11R. One of the snubber circuits 11 is connected in parallel to the U-phase upper and lower arm circuit 9HL. The other snubber circuit 11 is connected in parallel to the V-phase upper and lower arm circuit 9HL. The other snubber circuit 11 is connected in parallel to the W-phase upper and lower arm circuit 9HL.

[0038] The snubber circuit 12 is connected in parallel to the inverter 8, i.e., the upper and lower arm circuits 8HL. The snubber circuit 12 reduces the inductance of the upper and lower arm circuits 8HL, thereby enabling high-speed switching of the inverter 8. The snubber circuit 12 includes at least a capacitor 12C. The snubber circuit 12 may be, for example, a C snubber circuit, an RC snubber circuit, or an RCD snubber circuit. The snubber circuit 12 shown in FIG. 1 is an RC snubber circuit in which a capacitor 12C and a resistor 12R are connected in series. One end of the snubber circuit 12 is connected to the power supply line 5. The other end of the snubber circuit 12 is connected to the power supply line 6.

[0039] In the power conversion circuit 4 illustrated in FIG. 1, a snubber circuit 12 is provided for each phase of the upper and lower arm circuits 8HL. The power conversion circuit 4 includes three snubber circuits 12. One end of each snubber circuit 12 is connected to the power supply line 5, and the other end is connected to the power supply line 6. Each snubber circuit 12 includes a capacitor 12C and a resistor 12R. One of the snubber circuits 12 is connected in parallel to the U-phase upper and lower arm circuit 8HL. The other snubber circuit 12 is connected in parallel to the V-phase upper and lower arm circuit 8HL. The other snubber circuit 12 is connected in parallel to the W-phase upper and lower arm circuit 8HL.

[0040] As illustrated in FIG. 1, the power conversion circuit 4 may include a control unit (CTR) 15. The control unit 15 may include, for example, a processor 15a, a memory 15b, and a storage 15c. The processor 15a accesses the memory 15b to execute various processes. The memory 15b is a rewritable volatile storage medium. The memory 15b is, for example, a RAM. RAM is an abbreviation for Random Access Memory. The storage 15c is a rewritable nonvolatile memory. The storage 15c may be realized by at least one type of non-transitory tangible storage medium, such as a semiconductor memory, a magnetic medium, or an optical medium. The storage 15c may include multiple types of storage media, such as a ROM and a flash memory. ROM is an abbreviation for Read Only Memory.

[0041] The storage 15c stores a program 15d executed by the processor 15a. The program 15d configures a plurality of functional units by causing the processor 15a to execute a plurality of instructions. The processing performed by the control unit 15 may be realized by software processing in which the processor 15a executes the program 15d described above, or may be realized by hardware processing using a dedicated electronic circuit. It may also be realized by a combination of software processing and hardware processing. The program 15d includes a program for executing a rotation control process, which will be described later.

[0042] The control unit 15 may include, for example, a drive command generation unit and a drive circuit unit (not shown). The drive command generation unit controls the inverters 8 and 9. The drive command generation unit generates drive commands (command signals) for controlling the on / off of the MOSFETs 8S and 9S and outputs them to the drive circuit unit. The drive command generation unit generates drive commands based on drive requests for the rotating electric machine 3, such as torque command values ​​input from a higher-level ECU (not shown), and signals detected by various sensors. The various sensors may include current sensors, rotation angle sensors, voltage sensors, and the like (not shown). The current sensors detect phase currents flowing through the windings 3U, 3V, and 3W of each phase. The rotation angle sensor detects the rotation angle of the rotor of the rotating electric machine 3. The voltage sensor detects the voltage across the smoothing capacitor 7. Current sensors include current sensors 123 and 124 (described later). The drive command generation unit controls the changeover switch 10 (10A, 10B). The drive command generation unit generates drive commands for controlling the on / off of the changeover switch 10 and outputs the drive commands to the drive circuit unit. The drive circuit unit is sometimes referred to as a driver. The drive circuit unit can independently control the on / off of the MOSFET 8S, MOSFET 9S, and changeover switch 10 based on the drive commands. For convenience, signal lines for transmitting drive signals from the control unit 15 to each switching element are omitted in FIG. 1.

[0043] <Star connection drive and open connection drive> Next, star connection driving and open connection driving will be described with reference to Figures 2, 3, and 4. Figure 2 shows an example of an operating point map of a rotating electric machine, with the horizontal axis representing rotation speed and the vertical axis representing torque. Figure 3 is a diagram showing star connection driving. Figure 4 is a diagram showing open connection driving. For convenience, the control unit 15 is omitted from Figures 3 and 4.

[0044] As shown in FIG. 2, the driving range of the rotating electric machine 3 is divided into two ranges depending on the rotation speed and torque. One of the driving ranges is the star connection driving range. The star connection driving range is the normal use range. The other driving range is the open connection driving range. The open connection driving range is a range with higher rotation speeds or higher torque than the star connection driving range.

[0045] When the operating point is in the star connection drive region, the control unit 15 executes star connection drive control. Star connection drive is sometimes referred to as Y drive. The control unit 15 controls the MOSFETs 8S and 9S and the changeover switch 10 so that the windings 3U, 3V, and 3W are in a star connection state. Specifically, as shown in FIG. 3, the MOSFETs of the changeover switch 10 (10A, 10B) are turned off and the changeover switch 10 is opened. The inverter 9 is also neutralized. As shown in FIG. 3, for example, the MOSFETs 9S of the upper arms 9H of all phases may be turned on and the MOSFETs 9S of the lower arms 9L of all phases may be turned off. The MOSFETs 9S of the upper arms 9H of all phases may be turned off and the MOSFETs 9S of the lower arms 9L of all phases may be turned on. The MOSFETs 8S of the inverter 8 are then controlled according to drive requirements, etc.

[0046] FIG. 3 shows one current conduction pattern in star-connection drive. The dashed-dotted arrows in FIG. 3 indicate an example of a current path. FIG. 3 shows the current path when the MOSFET 8S in the U-phase upper arm 8H and the MOSFET 8S in the W-phase lower arm 8L are turned on. In the example shown in FIG. 3, the upper arm 9H of the inverter 9 is turned on and the lower arm 9L is turned off. The current flows in the following order: U-phase upper arm 8H → node U1 → U-phase winding 3U → node U2 → U-phase upper arm 9H → W-phase upper arm 9H → node W2 → W-phase winding 3W → node W1 → W-phase lower arm 8L. In this way, in star-connection drive, current flows without passing through the selector switch 10.

[0047] When the operating point is in the open connection drive region, the control unit 15 executes open connection drive control. Open connection drive is sometimes referred to as H drive. The control unit 15 turns on the MOSFET of the changeover switch 10 (10A, 10B) to close the changeover switch 10. The control unit 15 also opens the neutral point of the inverter 9. By opening the neutral point, an open connection circuit of the U-phase upper and lower arm circuits 8HL, 9HL is formed via the U-phase winding 3U. Similarly, an open connection circuit of the V-phase upper and lower arm circuits 8HL, 9HL is formed via the V-phase winding 3V. An open connection circuit of the W-phase upper and lower arm circuits 8HL, 9HL is formed via the W-phase winding 3W. The control unit 15 regards each phase as an independent open connection circuit and controls the applied voltage for each phase.

[0048] FIG. 4 shows one current conduction pattern in open-connection driving. The two-dot chain arrow in FIG. 4 indicates one example of a current path. FIG. 4 shows the current path when MOSFET 8S in W-phase lower arm 8L and MOSFET 9S in W-phase upper arm 9H are turned on. Current flows in the following order: changeover switch 10 → W-phase upper arm 9H → node W2 → W-phase winding 3W → node W1 → W-phase lower arm 8L. In this way, in open-connection driving, current flows via changeover switch 10.

[0049] As described above, the power conversion circuit 4 is configured to be switchable between star connection drive and open connection drive. The power conversion circuit 4 is configured to be able to execute star connection drive. The power conversion circuit 4 is configured to be able to execute open connection drive. By executing open connection drive instead of star connection drive, it is possible to output a higher rotation speed range or a higher torque range.

[0050] <Charging using a power conversion circuit> Next, charging using the power conversion circuit 4 will be described with reference to Fig. 5. Fig. 5 shows a circuit configuration showing a state in which an external device is connected. In Fig. 5, the external device is shown in a simplified form.

[0051] As shown in FIG. 5, the external device 16 is connected to the power supply lines 5 and 6. The external device 16 is connected in parallel to the DC power supply 2. The external device 16 is an element separate from the elements constituting the drive system 1. The external device 16 may be, for example, an element external to a moving body (vehicle). An example of the external device 16 is a charger. The charger charges the DC power supply 2. The voltage supplied by the external device 16 is lower than the power supply voltage of the DC power supply 2. For example, the DC power supply 2 is 800 V, and the external device 16 (charger) is 400 V. In the rotating electric machine 3 and the power conversion circuit 4, the windings 3U, 3V, and 3W of the rotating electric machine 3 and the upper and lower arm circuit 8HL constituting the inverter 8 function as a boost circuit.

[0052] The external device 16 is connected to the drive system 1 (power conversion circuit 4) while the vehicle is stopped, for example. When the external device 16 is connected, the control unit 15 controls the inverters 8 and 9 and the selector switch 10 to boost the supply voltage of the external device 16 and charge the DC power supply 2. The boost operation may use one phase or multiple phases (multi-phase). The control unit 15 turns off the MOSFET of the selector switch 10. In this state, the control unit 15 turns on the upper arm 9H of the inverter 9 and controls the on / off of the upper and lower MOSFETs 8S of the upper and lower arm circuit 8HL in the corresponding phase.

[0053] External device 16 may be a DC power supply (external power supply) separate from DC power supply 2. The external power supply may be, for example, a secondary battery or may include a DC-AC conversion circuit. DC power supply 2 charges external device 16. The power supply voltage of external device 16 is lower than the power supply voltage of DC power supply 2. In rotating electric machine 3 and power conversion circuit 4, windings 3U, 3V, 3W of rotating electric machine 3 and upper arm 8H of inverter 8 function as a step-down circuit.

[0054] When an external device 16 is connected to the drive system 1, the control unit 15 controls the inverters 8 and 9 and the selector switch 10 to step down the power supply voltage of the DC power supply 2 and charge the external device 16. In the step-down operation, one phase or multiple phases (multi-phase) may be used. The control unit 15 turns off the MOSFET of the selector switch 10. In this state, the control unit 15 turns on the upper arm 9H of the inverter 9 and controls the on / off of the MOSFET 8S of the upper arm 8H of the corresponding phase. The MOSFET 8S of the lower arm 8L of the corresponding phase is turned off. When the MOSFET 8S of the upper arm 8H is turned off, a current flows through the diode of the lower arm 8L of the corresponding phase.

[0055] <Current sensor> As shown in FIG. 1, the drive system 1 has an output current sensor 123 and a switching current sensor 124. The output current sensor 123 detects the phase current flowing through the windings 3U, 3V, and 3W of each phase. The output current sensor 123 corresponds to a winding current sensor. The output current sensor 123 is a magnetic sensor such as a Hall sensor. The magnetic sensor is formed to include a sensor element such as a Hall element. The output current sensor 123 may also be formed to include a resistive element such as a shunt resistor.

[0056] An output current sensor 123 is provided for each of the three phases. For example, an output current sensor 123 is provided for each of the U, V, and W phases. The U phase corresponds to the first phase, the V phase corresponds to the second phase, and the W phase corresponds to the third phase. The U-phase winding 3U corresponds to the first phase winding, the V-phase winding 3V corresponds to the second phase winding, and the W-phase winding 3W corresponds to the third phase winding.

[0057] Output current sensors 123 include U-phase output current sensor 123U, V-phase output current sensor 123V, and W-phase output current sensor 123W. Output current sensor 123U detects the current flowing through U-phase winding 3U. Output current sensor 123V detects the current flowing through V-phase winding 3V. Output current sensor 123W detects the current flowing through W-phase winding 3W. Output current sensor 123U corresponds to the first phase sensor, output current sensor 123V corresponds to the second phase sensor, and output current sensor 123W corresponds to the third phase sensor.

[0058] The output current sensor 123 is provided on only one of the output lines 13 and 14. For example, the output current sensor 123 is provided on one output line 14, but not on the other. The output current sensor 123 is provided on the output line 14 between the windings 3U, 3V, and 3W and the inverter 9. The output line 13 corresponds to the first path, and the output line 14 corresponds to the second path. The output current sensor 123U detects the current flowing in the U-phase output line 14 as the current flowing in the U-phase winding 3U. The output current sensor 123V detects the current flowing in the V-phase output line 14 as the current flowing in the V-phase winding 3V. The output current sensor 123W detects the current flowing in the W-phase output line 14 as the current flowing in the W-phase winding 3W.

[0059] The power supply lines 5 and 6 connect the inverter 8 and the inverter 9 without passing through the windings 3U, 3V, and 3W. The power supply lines 5 and 6 correspond to direct paths. In the power supply line 5, the wiring 5A connects the inverter 8 and the inverter 9. The wiring 5A connects the upper arm 8H and the upper arm 9H. The wiring 5A corresponds to the upper direct path. In the power supply line 6, the wiring 6A connects the inverter 8 and the inverter 9. The wiring 6A connects the lower arm 8L and the lower arm 9L. The wiring 6A corresponds to the lower direct path. The power supply lines 5 and 6 electrically connect the DC power supply 2 and the inverters 8 and 9.

[0060] The switching current sensor 124 detects the current flowing through the wirings 5A and 6A. That is, the switching current sensor 124N detects the current flowing through the changeover switch 10. The switching current sensor 124 corresponds to a direct current sensor. Like the output current sensor 123, the switching current sensor 124 is a magnetic sensor such as a Hall sensor. Note that the switching current sensor 124 may be formed to include a resistive element such as a shunt resistor.

[0061] The switching current sensors 124 are provided on the wiring 5A and the wiring 6A, respectively. The switching current sensors 124 include a high-potential side switching current sensor 124P and a low-potential side switching current sensor 124N. The switching current sensor 124P detects the current flowing through the wiring 5A. The switching current sensor 124P is provided on the wiring 5A between the inverter 9 and the selector switch 10A. The switching current sensor 124P corresponds to an upper sensor. The switching current sensor 124P may also be provided on the wiring 5A between the inverter 8 and the selector switch 10A.

[0062] The switching current sensor 124N detects the current flowing through the wiring 6A. The switching current sensor 124N is provided on the wiring 6A between the inverter 9 and the changeover switch 10B. The switching current sensor 124N corresponds to a lower sensor. The switching current sensor 124N may also be provided on the wiring 6A between the inverter 8 and the changeover switch 10B.

[0063] Current sensors 123, 124 are communicatively connected to control unit 15. Current sensors 123, 124 output to control unit 15 detection signals corresponding to the currents flowing through windings 3U, 3V, 3W.

[0064] In the drive system 1, the power conversion circuit 4 is provided by a power conversion module. The power conversion module provides inverters 8 and 9, a changeover switch 10, snubber circuits 11 and 12, etc. The power conversion module has a housing, a substrate, semiconductor elements, snubber components, a changeover switch component, a current sensor element, etc. The substrate and semiconductor elements are components that provide the inverters 8 and 9. The semiconductor elements include a MOSFET 8S and a first semiconductor element that provides the MOSFET 8S, and a second semiconductor element that provides the MOSFET 9S and the MOSFET 9S. The changeover switch component is a component that provides the changeover switch 10. The snubber component is a component that provides the snubber circuits 11 and 12. The current sensor element is a component that provides current sensors 123 and 124. The housing accommodates the substrate, semiconductor elements, changeover switch components, snubber components, current sensor element, etc.

[0065] The control unit 15 performs rotation control, which is control of the rotating electric machine 3. The rotation control includes control of star connection drive and control of open connection drive. The rotation control also includes control of the power conversion circuit 4. The control of the power conversion circuit 4 includes control of the inverters 8 and 9 and control of the changeover switch 10. The control unit 15 performs rotation control by executing a rotation control process. The control unit 15 repeatedly executes the rotation control process at a predetermined control period. The control unit 15 has a function of executing the processing of each step of the rotation control process. The rotation control process will be described with reference to the flowchart of FIG. 6.

[0066] Control unit 15 performs a current detection process in step S101 shown in Fig. 6. In the current detection process, a process for detecting the current flowing through windings 3U, 3V, and 3W and a process for detecting the current flowing through wiring 5A and 6A are performed. In the current detection process, a detection value Id is detected. The detection value Id is the detection value of the current flowing through windings 3U, 3V, and 3W and wiring 5A and 6A. Control unit 15 acquires the detection value Id using the detection signals of current sensors 123 and 124. The detection value Id corresponds to the detection result of current sensors 123 and 124. The function of control unit 15 that executes the process of step S101 corresponds to a current acquisition unit.

[0067] The detected values ​​Id include a U-phase detected value IdU, a V-phase detected value IdV, a W-phase detected value IdW, a P-detected value IdP, and an N-detected value IdN. The U-phase detected value IdU is a detected value of the current flowing through the U-phase winding 3U. The V-phase detected value IdV is a detected value of the current flowing through the V-phase winding 3V. The W-phase detected value IdW is a detected value of the current flowing through the W-phase winding 3W. The control unit 15 calculates the detected values ​​IdU, IdV, and IdW using the detection signals of the output current sensors 123U, 123V, and 123W. The detected values ​​IdU, IdV, and IdW are the detection results of the output current sensors 123U, 123V, and 123W. The detected values ​​IdU, IdV, and IdW correspond to the winding detected values.

[0068] The P detection value IdP is the detection value of the current flowing through the wiring 5A. The N detection value IdN is the detection value of the current flowing through the wiring 6A. The control unit 15 calculates the detection values ​​IdP and IdN using the detection signals of the switching current sensors 124P and 124N. The detection values ​​IdP and IdN are the detection results of the switching current sensors 124P and 124N. The detection values ​​IdP and IdN correspond to direct detection values.

[0069] In steps S102 to S104, the control unit 15 performs an abnormality determination process to determine whether an abnormality has occurred in the current sensors 123, 124. In the abnormality determination process, it is determined whether an abnormality has occurred in at least one of the output current sensor 123 and the switching sensor. For example, in the abnormality determination process, it is determined whether an abnormality has occurred in at least one of the output current sensor 123U, the output current sensor 123V, the output current sensor 123W, the switching current sensor 124P, and the switching current sensor 124N. The function of the control unit 15 that executes the processes of steps S102 to S104 corresponds to the abnormality determination unit.

[0070] In step S102, the control unit 15 calculates the estimated value Ic using the detected value Id. The estimated value Ic is a current value for confirming that the current sensors 123, 124 are normal. In other words, the estimated value Ic is a value for determining whether or not an abnormality has occurred in the current sensors 123, 124. The control unit 15 estimates the estimated value Ic using the detected value Id. The estimated value Ic is a value estimated from at least one detected value Id. The function of the control unit 15 that executes the processing of step S102 corresponds to the current estimation unit. The estimated value Ic corresponds to the estimation result of the current estimation unit.

[0071] The control unit 15 calculates an estimated value Ic for each of the U-phase winding 3U, the V-phase winding 3V, the W-phase winding 3W, the wiring 5A, and the wiring 6A. The estimated values ​​Ic include a U-phase estimated value IcU, a V-phase estimated value IcV, a W-phase estimated value IcW, a P estimated value IcP, and an N estimated value IcN. The control unit 15 uses four of the five detected values ​​Id, namely the U-phase detected value IdU, the V-phase detected value IdV, the W-phase detected value IdW, the P detected value IdP, and the N detected value IdN, to calculate the estimated value Ic by estimating the remaining detected value Id. The U-phase detected value IdU, the V-phase detected value IdV, and the W-phase detected value IdW correspond to winding estimated values. The P detected value IdP and the N detected value IdN correspond to direct estimated values.

[0072] The control unit 15 calculates the estimated value Ic from the detected value Id using current correlation information indicating the correlation between the currents flowing through the U-phase winding 3U, the V-phase winding 3V, the W-phase winding 3W, the wiring 5A, and the wiring 6A. The current correlation information includes correlations between the currents flowing through the U-phase winding 3U, the V-phase winding 3V, the W-phase winding 3W, the wiring 5A, and the wiring 6A. The current correlation information also includes correlations between the currents flowing through the windings 3U, 3V, and 3W and the currents flowing through the output line 13 and the output line 14. The current correlation information may be a map, an arithmetic expression, a function, or the like. The current correlation information is stored in the memory 15b or the like.

[0073] For example, the control unit 15 uses four detection values ​​Id, namely, the V-phase detection value IdV, the W-phase detection value IdW, the P detection value IdP, and the N detection value IdN, to calculate the remaining U-phase detection value IdU, thereby calculating a U-phase estimated value IcU. That is, the control unit 15 calculates the U-phase estimated value IcU using four of the five detection values ​​Id, excluding the U-phase detection value IdU. The control unit 15 also calculates the V-phase estimated value IcV using four of the five detection values ​​Id, excluding the V-phase detection value IdV. The control unit 15 calculates the W-phase estimated value IcW using four of the five detection values ​​Id, excluding the W-phase detection value IdW. The control unit 15 calculates the P-estimated value IcP using four of the five detection values ​​Id, excluding the P detection value IdP. The control unit 15 calculates the N estimated value IcN using four detected values ​​Id excluding the N detected value IdN from the five detected values ​​Id.

[0074] In step S103, the control unit 15 calculates a deviation value Ie using the detected value Id and the estimated value Ic. The deviation value Ie is the difference between the detected value Id and the estimated value Ic. The control unit 15 calculates a U-phase deviation value IeU, a V-phase deviation value IeV, a W-phase deviation value IeW, a P deviation value IeP, and an N deviation value IeN for each of the U-phase detected value IdU, the V-phase detected value IdV, the W-phase detected value IdW, the P detected value IdP, and the N detected value IdN. The U-phase deviation value IeU is the difference between the U-phase detected value IdU and the U-phase estimated value IcU. The V-phase deviation value IeV is the difference between the V-phase detected value IdV and the V-phase estimated value IcV. The W-phase deviation value IeW is the difference between the W-phase detected value IdW and the W-phase estimated value IcW. The P deviation value IeP is the difference between the P detected value IdP and the P estimated value IcP. The N deviation value IeN is the difference between the N detected value IdN and the N estimated value IcN.

[0075] In step S104, the control unit 15 determines whether the deviation value Ie is greater than the deviation threshold value Je. If the absolute value of the deviation value Ie is greater than the deviation threshold value Je, the control unit 15 determines that the deviation value Ie is greater than the deviation threshold value Je. The deviation threshold value Je is a value determined in advance by testing or the like, and is stored in the memory 15b or the like. The deviation threshold value Je is a value that indicates that the deviation value Ie is abnormally large. The deviation value Ie may become greater than the deviation threshold value Je when an abnormality such as a failure occurs in the output current sensor 123 or the switching current sensor 124.

[0076] The control unit 15 determines whether each of the five deviation values ​​Ie, namely, the U-phase deviation value IeU, the V-phase deviation value IeV, the W-phase deviation value IeW, the P-phase deviation value IeP, and the N-phase deviation value IeN, is greater than the deviation threshold value Je. If at least one of the five deviation values ​​Ie is greater than the deviation threshold value Je, the control unit 15 determines that the deviation value Ie is greater than the deviation threshold value Je. In this case, the control unit 15 determines that an abnormality has occurred in at least one of the current sensors 123U, 123V, 123W, 124P, and 124N. Furthermore, if none of the five deviation values ​​Ie is greater than the deviation threshold value Je, the control unit 15 determines that the deviation value Ie is not greater than the deviation threshold value Je. In this case, the control unit 15 determines that no abnormality has occurred in any of the current sensors 123U, 123V, 123W, 124P, and 124N.

[0077] For example, if the U-phase deviation value IeU is greater than the deviation threshold Je, the control unit 15 determines that the output current sensor 123U is an abnormal sensor. The abnormal sensor is a current sensor among the current sensors 123U, 123V, 123W, 124P, and 124N in which an abnormality has occurred. Also, if the V-phase deviation value IeV is greater than the deviation threshold Je, the control unit 15 determines that the output current sensor 123V is an abnormal sensor. If the W-phase deviation value IeW is greater than the deviation threshold Je, the control unit 15 determines that the output current sensor 123W is an abnormal sensor. If the P deviation value IeP is greater than the deviation threshold Je, the control unit 15 determines that the switching current sensor 124P is an abnormal sensor. If the N deviation value IeN is greater than the deviation threshold Je, the control unit 15 determines that the switching current sensor 124N is an abnormal sensor.

[0078] If the deviation value Ie is not greater than the deviation threshold Je, the control unit 15 proceeds to step S105. In step S105, the control unit 15 uses the detection value Id to determine whether or not a current conduction abnormality has occurred. Examples of current conduction abnormalities include abnormalities that have occurred in the current conduction paths, such as the power supply lines 5 and 6, the selector switch 10, the output lines 13 and 14, and the windings 3U, 3V, and 3W. Examples of abnormalities in the current conduction paths include a short circuit, leakage current, or ground fault in the output line 14.

[0079] The control unit 15 can determine whether or not an inter-phase short circuit has occurred in the output wires 14. For example, if the W-phase detection value IdW is normal, while both the U-phase detection value IdU and the V-phase detection value IdV are abnormal, the control unit 15 determines that an inter-phase short circuit, such as a short circuit between the U-phase output wire 14 and the V-phase output wire 14, has occurred. Furthermore, if the detection values ​​IdU, IdV, and IdW are normal, while the P-detection value IdP and the N-detection value IdN are abnormal, the control unit 15 determines that a short circuit, such as a short circuit between the wiring 5A and the wiring 6A, has occurred.

[0080] Furthermore, an abnormality in the conduction of the power lines 5 and 6 may include an abnormality in the changeover switch 10. Abnormalities in the changeover switch 10 include a hold-closed abnormality and a hold-open abnormality. A hold-closed abnormality is an abnormality in which the changeover switch 10 is held in the closed state and cannot be shifted to the open state. A hold-open abnormality is an abnormality in which the changeover switch 10 is held in the open state and cannot be shifted to the closed state. When a hold-closed abnormality or a hold-open abnormality occurs in the changeover switch 10, the detection value Id of the switching current sensor 124 does not change even when the control unit 15 outputs a command signal to the changeover switch 10. Therefore, when the detection values ​​IdP and IdN do not change even when the control unit 15 outputs a command signal to the changeover switch 10, the control unit 15 determines that an abnormality may have occurred in the changeover switches 10A and 10B.

[0081] If a current supply abnormality occurs, the control unit 15 proceeds to step S115 and performs a current supply stop process. In the current supply stop process, a process for stopping current supply to the windings 3U, 3V, and 3W is performed. The control unit 15 can stop the driving of the rotating electric machine 3 by the current supply stop process. However, the current supply stop process does not necessarily stop the driving of the rotating electric machine 3. For example, if it is not possible to stop the moving body, the control unit 15 may continue the supply of current to the windings 3U, 3V, and 3W so that the rotating electric machine 3 operates at the minimum necessary output. In the current supply stop process, a notification process may be performed to notify an occupant or the like of abnormality information regarding the current supply abnormality. In the notification process, the abnormality information is notified to the occupant or the like by sound, image, or the like. The abnormality information includes the location where the current supply abnormality occurred, the type of the current supply abnormality, and the like.

[0082] If no abnormality in electrical conduction has occurred, the control unit 15 performs normal control to drive the rotating electric machine 3 in steps S106 and S107. The control unit 15 sets normal parameters in step S106 of the normal control. The normal parameters are control parameters used in the normal control. The control unit 15 sets at least one of the detection values ​​IdU, IdV, IdW, IdP, and IdN as the control parameters. For example, the control unit 15 sets the U-phase detection value IdU, the V-phase detection value IdV, and the W-phase detection value IdW as the control parameters, but does not set the P detection value IdP and the N detection value IdN as the control parameters.

[0083] The control unit 15 performs normal drive processing in step S107. In the normal drive processing, processing for driving the rotating electric machine 3 is performed using control parameters. The control unit 15 drives the rotating electric machine 3 using the U-phase detected value IdU, the V-phase detected value IdV, and the W-phase detected value IdW. The control unit 15 can drive the rotating electric machine 3 by star connection drive or open connection drive. The function of the control unit 15 for executing steps S106 and S107 includes a function for star connection drive of the rotating electric machine 3 and a function for open connection drive of the rotating electric machine 3.

[0084] In step S104, if the deviation value Ie is greater than the deviation threshold Je, the control unit 15 determines that an abnormality has occurred in the output current sensor 123 or the switching current sensor 124, and proceeds to step S108. In step S108, the control unit 15 performs an alert process. The alert process includes a process for notifying the driver that an abnormality has occurred in the output current sensor 123 or the switching current sensor 124. The alert process notifies the driver or other personnel of the abnormality in the output current sensor 123 or the switching current sensor 124 by sound, image, or the like.

[0085] In steps S109 to S114, the control unit 15 performs fail-safe control for driving the rotating electric machine 3 in a situation where an abnormal sensor is present. In step S109 of the fail-safe control, the control unit 15 determines whether the output current sensor 123 is normal. The output current sensor 123 is sometimes referred to as a three-phase sensor. For example, the control unit 15 determines whether the output current sensor 123 is an abnormal sensor. If the output current sensor 123 is not an abnormal sensor, the control unit 15 determines that the output current sensor 123 is normal. In this case, the control unit 15 determines that the switching current sensor 124 is an abnormal sensor.

[0086] If the output current sensor 123 is normal, the control unit 15 proceeds to step S110 and performs parameter unchanged processing. The parameter unchanged processing is processing for not changing the fail-safe parameters from the normal parameters. The fail-safe parameters are control parameters used for fail-safe control. The control unit 15 sets the U-phase detected value IdU, the V-phase detected value IdV, and the W-phase detected value IdW as fail-safe parameters, but does not set the P-detected value IdP and the N-detected value IdN as fail-safe parameters. The control unit 15 sets the control parameters that were set to the normal parameters in step S106 as fail-safe parameters.

[0087] If the output current sensor 123 is not normal, the control unit 15 proceeds to step S111 and performs a parameter change process. The parameter change process is a process for changing the fail-safe parameters from the normal parameters. The control unit 15 sets the detected values ​​that are not abnormal among the U-phase detected value IdU, the V-phase detected value IdV, and the W-phase detected value IdW, as well as the P-detected value IdP and the N-detected value IdN, as the fail-safe parameters.

[0088] After setting the fail-safe parameters in steps S110 and S111, the control unit 15 determines in step S112 whether open connection driving is necessary. For example, it determines whether the rotating electric machine 3 needs to be driven at high rotation speed or high torque in order to move the moving body. If it is necessary to drive the rotating electric machine 3 at high rotation speed or high torque, the control unit 15 determines that open connection driving is necessary.

[0089] If open connection drive is necessary, the control unit 15 proceeds to step S113 and performs star connection drive processing. In the star connection drive processing, processing is performed to drive the rotating electric machine 3 in a star connection manner using fail-safe parameters. If open connection drive is not necessary, the control unit 15 proceeds to step S114 and performs open connection drive processing. In the open connection drive processing, processing is performed to drive the rotating electric machine 3 in an open connection manner using fail-safe parameters.

[0090] When performing normal control, the control unit 15 may set all of the detected values ​​IdU, IdV, IdW, IdP, and IdN as control parameters. When at least one of the detected values ​​IdU, IdV, IdW, IdP, and IdN is an abnormal value, the control unit 15 may set all of the detected values ​​Id that are normal values ​​among the detected values ​​IdU, IdV, IdW, IdP, and IdN as fail-safe parameters. In this case, the control unit 15 may set the estimated value Ic as a fail-safe parameter in addition to all of the detected values ​​Id that are normal values ​​among the detected values ​​IdU, IdV, IdW, IdP, and IdN.

[0091] <Summary of the First Embodiment> According to this embodiment, the current flowing through the windings 3U, 3V, and 3W is detected by the output current sensor 123, and the current flowing through the wiring 5A and 6A of the power supply lines 5 and 6 is detected by the switching current sensor 124. With this configuration, it is possible to detect the occurrence of an abnormality in the windings 3U, 3V, and 3W, the power supply lines 5 and 6, the output current sensor 123, or the switching current sensor 124 using the detection value Id of the output current sensor 123 and the detection value Id of the switching current sensor 124. In other words, it is possible to detect an abnormality in the current path or the current sensors 123 and 124.

[0092] According to this embodiment, the output current sensor 123 detects the current flowing through the output line 14. In this configuration, the current flowing through the output line 14 can be used to detect the occurrence of an abnormality in the output line 14, the output current sensor 123, or the switching current sensor 124.

[0093] In a configuration in which the heat generated by inverter 9 is likely to be smaller than the heat generated by inverter 8, it is preferable to provide output current sensor 123 on output line 14. In this way, by providing output current sensor 123 on the side of inverter 9, which generates less heat, of inverters 8, 9, it is possible to prevent heat from being transferred from inverter 8, which generates more heat, to output current sensor 123. This makes it possible to prevent the detection accuracy of output current sensor 123 from being reduced by the heat from inverter 8, which generates more heat.

[0094] In this embodiment, the inverters 8 and 9 can be driven in a star connection to neutralize the inverter 9. When the power conversion circuit 4 is driven in a star connection, the MOSFET 9S of the inverter 9 is kept on or off to neutralize the inverter 9. In this case, the number of times the MOSFET 9S is switched per unit time is smaller than when the power conversion circuit 4 is driven in an open connection, and therefore heat generated by driving the semiconductor element is reduced. This prevents heat from being transferred from the semiconductor element to the current sensor element in the power conversion module, which would otherwise cause a decrease in the detection accuracy of the output current sensor 123.

[0095] According to the present embodiment, the control unit 15 determines whether an abnormality has occurred in the current sensors 123, 124 by using the detection values ​​Id of the current sensors 123, 124 and the estimated values ​​Ic of the currents flowing through the windings 3U, 3V, and 3W and the wirings 5A and 6A. With this configuration, an abnormality in the current sensors 123, 124 can be detected by, for example, calculating the difference between the detection value Id and the estimated value Ic for the current flowing through one current path. Therefore, the accuracy of detecting an abnormality in the current sensors 123, 124 can be improved compared to, for example, a configuration that, unlike the present embodiment, detects an abnormality in the current sensors 123, 124 by using only the detection value Id out of the detection value Id and the estimated value Ic.

[0096] According to this embodiment, the control unit 15 determines whether an abnormality has occurred in the output current sensor 123 using the detected values ​​IdU, IdV, and IdW and the estimated values ​​IcU, IcV, and IcW. With this configuration, it is possible to detect an abnormality in the output current sensor 123 by calculating the difference between the detected values ​​IdU, IdV, and IdW and the estimated values ​​IcU, IcV, and IcW for the currents flowing through the windings 3U, 3V, and 3W. The control unit 15 also determines whether an abnormality has occurred in the switching current sensor 124 using the detected values ​​IdP and IdN and the estimated values ​​IcP and IcN. With this configuration, it is possible to detect an abnormality in the switching current sensor 124 by calculating the difference between the detected values ​​IdP and IdN and the estimated values ​​IcP and IcN for the currents flowing through the wirings 5A and 6A.

[0097] According to this embodiment, in the power conversion circuit 4, the output current sensors 123U, 123V, and 123W detect the detected values ​​IdU, IdV, and IdW, and the switching current sensors 124P and 124N detect the detected values ​​IdP and IdN. This configuration makes it possible to calculate the estimated values ​​IcU, IcV, IcW, IcP, and IcN for the U-phase winding 3U, the V-phase winding 3V, the W-phase winding 3W, the wiring 5A, and the wiring 6A. Therefore, by using the detected values ​​IdU, IdV, IdW, IdP, and IdN and the estimated values ​​IcU, IcV, IcW, IcP, and IcN, it is possible to individually determine whether an abnormality has occurred for each of the current sensors 123U, 123V, 123W, 124P, and 124N.

[0098] According to this embodiment, the control unit 15 uses four of the five detection values ​​Id, namely, IdU, IdV, IdW, IdP, and IdN, to calculate the estimated value Ic for the remaining detection value Id. Therefore, the estimated value Ic for the remaining detection value Id can be calculated with high accuracy.

[0099] Furthermore, the control unit 15 determines whether or not an abnormality has occurred in each of the current sensors 123U, 123V, 123W, 124P, and 124N using the detected values ​​IdU, IdV, IdW, IdP, and IdN and the estimated values ​​IcU, IcV, IcW, IcP, and IcN. In this configuration, the estimated values ​​IcU, IcV, IcW, IcP, and IcN are calculated with high accuracy, and therefore, the accuracy of abnormality detection for the current sensors 123U, 123V, 123W, 124P, and 124N can be improved.

[0100] According to this embodiment, the changeover switch 10 is provided on the wirings 5A and 6A. In this configuration, the current-carrying state of the wirings 5A and 6A is switched by switching the changeover switch 10 between an open state and a closed state. Therefore, by calculating the difference between the detected values ​​IdU, IdV, and IdW and the estimated values ​​IcU, IcV, and IcW of the currents flowing through the wirings 5A and 6A, it is possible to detect an abnormality in the changeover switch 10, in addition to an abnormality in the switching current sensor 124.

[0101] 7 and 8 show reference examples of power conversion circuits. Fig. 7 shows an example of a current conduction pattern when star-connected driving is performed in the reference example. Fig. 8 shows a current conduction pattern with timing different from that in Fig. 4 when star-connected driving is performed. In the reference example, the symbols of related elements shown in this embodiment are indicated by adding r to the end.

[0102] The control unit performs star connection drive while switching between multiple current conduction patterns. The control unit performs star connection drive using, for example, a PWM control method. PWM is an abbreviation for Pulse Width Modulation. The multiple current conduction patterns include the zero vector current conduction patterns shown in Figures 7 and 8. The current conduction pattern shown in Figure 7 is a zero vector pattern in which all upper arms 8Hr of the inverter 8r are turned on and all lower arms 8Lr are turned off. The current conduction pattern shown in Figure 8 is a zero vector pattern in which all lower arms 8Lr of the inverter 8r are turned on and all upper arms 8Hr are turned off. The power line 5r has a wiring 5A11r connecting the inverter 8 and the selector switch 10r and a wiring 5A12r connecting the selector switch 10r and the inverter 9r.

[0103] As shown in Figures 7 and 8, in the power conversion circuit 4r of the reference example, the snubber circuit 11r connected in parallel to the inverter 9r is connected to a wiring 5A12r of the power line 5r that connects the selector switch 10r and the inverter 9r. One end of the snubber circuit 11r is connected to the wiring 5A12r of the power line 5r, and the other end is connected to the power line 6r. For convenience, Figures 7 and 8 omit the smoothing capacitor and the snubber circuit connected in parallel to the inverter 8r. Furthermore, the snubber circuit 11r is common to each phase of the inverter 9r.

[0104] In the examples shown in Figures 7 and 8, inverter 9r is neutralized by turning on all three upper arms 9Hr of inverter 9r. In this state, as shown in Figure 7, when all three upper arms 8Hr of inverter 8r are turned on, the voltage across capacitor 11Cr becomes approximately equal to the supply voltage of DC power supply 2r, i.e., power supply voltage Vdc. Furthermore, as shown in Figure 8, when all three lower arms 8Lr of inverter 8r are turned on, the voltage across capacitor 11Cr becomes approximately 0 V (zero volts).

[0105] As described above, star connection driving is performed while switching between multiple current patterns, so the voltage across capacitor 11Cr of snubber circuit 11r fluctuates during star connection driving. The voltage across capacitor 11Cr fluctuates between 0 V and Vdc. As a result, capacitor 11Cr is charged and discharged during star connection driving, resulting in low power conversion efficiency. Resistor 11Rr of snubber circuit 11r consumes the energy stored in capacitor 11Cr and generates heat. This heat affects capacitor 11Cr.

[0106] In contrast to this reference example, in this embodiment, in which the changeover switch 10B is provided on the wiring 6A, the MOSFET of the changeover switch 10B is off, i.e., the changeover switch 10B is in an open state, during star connection driving. Therefore, the potential on the negative side of the capacitor 11C provided in the snubber circuit 11 becomes a floating potential. Therefore, fluctuations in the voltage across the capacitor 11C can be suppressed during star connection driving. In other words, charging and discharging of the capacitor 11C can be suppressed. This improves power conversion efficiency. Furthermore, the effect of heat generated by the resistor 11R due to charging and discharging can be suppressed on the capacitor 11C. This is suitable not only for open connection driving but also for star connection driving.

[0107] <Modification> In the present embodiment, an example has been shown in which the changeover switch 10 is provided on each of the wiring 5A and the wiring 6A, but this is not limiting. The changeover switch 10 may be provided on only one of the wiring 5A and the wiring 6A. For example, as shown in FIG. 9, the changeover switch 10 may be provided on the wiring 5A but not on the wiring 6A.

[0108] In the present embodiment, an example has been shown in which a changeover switch 10 and a snubber circuit 11 are provided for each phase of the upper and lower arm circuits 9HL, but the present invention is not limited to this. For example, as shown in Fig. 10 and Fig. 11, one changeover switch 10 and one snubber circuit 11 may be provided for each of the three-phase upper and lower arm circuits 9HL that constitute the inverter 9.

[0109] In the present embodiment, an example has been shown in which one end of the snubber circuit 11 is connected to the inverter 9 on the power line 5 without passing through the changeover switch 10, but the present invention is not limited to this. For example, as shown in FIGS. 10 and 12 , one end of the snubber circuit 11 may be connected to the inverter 9 on the power line 5 via the changeover switch 10. That is, one end of the snubber circuit 11 may be connected between the changeover switch 10 and the inverter 8 on the wiring 5A. For example, the power line 5 has a wiring 5A1 that connects the inverter 8 and the changeover switch 10, and a wiring 5A2 that connects the changeover switch 10 and the inverter 9. In this configuration, one end of the snubber circuit 11 is connected to the wiring 5A1 of the wiring 5A1 and the wiring 5A2.

[0110] (Second embodiment) This embodiment is a modification based on the previous embodiment, and the description of the previous embodiment can be used. In the previous embodiment, the output current sensor 123 is provided on the output line 14, but this is not limiting. In this embodiment, the output current sensor 123 may be provided on the output line 13.

[0111] <Power conversion circuit> Fig. 13 shows a power conversion circuit 4 according to this embodiment. In the power conversion circuit 4 shown in Fig. 13, an output current sensor 123 is provided in output line 13 between windings 3U, 3V, and 3W and inverter 8. Output current sensor 123U detects the current flowing in U-phase output line 13 as the current flowing in U-phase winding 3U. Output current sensor 123V detects the current flowing in V-phase output line 13 as the current flowing in V-phase winding 3V. Output current sensor 123W detects the current flowing in W-phase output line 13 as the current flowing in W-phase winding 3W.

[0112] The switching current sensor 124 is provided on the wiring 5A, 6A closer to the inverter 8 than the changeover switch 10. The switching current sensor 124P is provided on the wiring 5A between the inverter 8 and the changeover switch 10. The switching current sensor 124N is provided on the wiring 6A between the inverter 8 and the changeover switch 10.

[0113] According to this embodiment, the output current sensor 123 detects the current flowing through the output line 13. In this configuration, the current flowing through the output line 13 can be used to detect that an abnormality has occurred in the output current sensor 123 or the switching current sensor 124.

[0114] In a configuration in which the heat generated by inverter 8 is likely to be smaller than the heat generated by inverter 9, it is preferable to provide output current sensor 123 on output line 13. In this way, by providing output current sensor 123 on the side of inverter 8, which generates less heat, of inverters 8 and 9, it is possible to prevent heat from being transferred from inverter 9, which generates more heat, to output current sensor 123. This makes it possible to prevent the detection accuracy of output current sensor 123 from being reduced by the heat from inverter 9, which generates more heat.

[0115] In the power conversion module, the changeover switch component is located closer to the second semiconductor component than the first semiconductor component. In this configuration, the changeover switch component is located as far away from the first semiconductor element as possible. Therefore, even if heat is generated in the changeover switch component, the heat is less likely to be transmitted to the first semiconductor element. By making it less likely for the heat of the changeover switch component to be transmitted to the first semiconductor element, the heat of the changeover switch component is less likely to be transmitted to the bus bar that forms at least a part of the output line 13. Therefore, even if a current sensor element is provided on this bus bar, the heat of the changeover switch component is less likely to be transmitted to the current sensor element. This prevents the detection accuracy of the output current sensor 123 from being reduced due to the heat generated in the changeover switch component.

[0116] (Third embodiment) This embodiment is a modification based on the previous embodiment, and the description of the previous embodiment can be used. In the previous embodiment, the switching current sensor 124 is provided on each of the power supply lines 5 and 6, but this is not limited to this. In this embodiment, the switching current sensor 124 may be provided on one of the power supply lines 5 and 6.

[0117] <Power conversion circuit> Fig. 14 shows a power conversion circuit 4 according to this embodiment. In the power conversion circuit 4 shown in Fig. 14, the switching current sensor 124 is provided on the power supply line 5, but is not provided on the power supply line 6. That is, the switching current sensor 124P is provided on the wiring 5A, but the switching current sensor 124N is not provided on the wiring 6A.

[0118] The control unit 15 can calculate the P detected value IdP but cannot calculate the N detected value IdN. Similar to the first embodiment, the control unit 15 calculates an estimated value IcN of the current flowing through the wiring 6A using four detected values ​​Id, namely, IdU, IdV, IdW, and IdP. The control unit 15 may set the detected values ​​IdU, IdV, and IdW as normal parameters, or may set the detected values ​​IdU, IdV, IdW, and IdP and the estimated value IcN as normal parameters. Furthermore, if any of the detected values ​​IdU, IdV, IdW, and IdP becomes an abnormal value, the control unit 15 may set the normal value of the detected values ​​IdU, IdV, IdW, and IdP as a fail-safe parameter. In this case, the control unit 15 may set the estimated value IcN as a fail-safe parameter in addition to the normal value.

[0119] In a configuration in which the switching current sensor 124N is provided on the wiring 6A and the switching current sensor 124P is not provided on the wiring 5A, the control unit 15 can calculate the N detection value IdN but cannot calculate the P detection value IdP. Even in this configuration, the control unit 15 can determine whether an abnormality has occurred in the current paths such as the output lines 13 and 14 and the windings 3U, 3V, and 3W by using the current correlation information. For example, as described above, the control unit 15 can determine the occurrence of a correlation short circuit using the detection values ​​IdU, IdV, and IdW.

[0120] (Fourth embodiment) This embodiment is a modification based on the previous embodiment, and the description of the previous embodiment can be used. In the previous embodiment, the output current sensor 123 is provided for each of the three phases, but this is not limited to this. In this embodiment, the output current sensor 123 may be provided for at least one of the three phases.

[0121] <Power conversion circuit> Fig. 15 shows a power conversion circuit 4 according to this embodiment. In the power conversion circuit 4 shown in Fig. 15, output current sensors 123 are provided in the output lines 14 of two of the three phases, but are not provided in the output line 14 of the remaining phase. For example, an output current sensor 123 is provided in each of the U-phase output line 14 and the V-phase output line 14, but is not provided in the W-phase output line 14.

[0122] The control unit 15 detects the U-phase detected value IdU and the V-phase detected value IdV, but does not calculate the W-phase detected value IdW. Similar to the first embodiment, the control unit 15 calculates an estimated value IcW of the current flowing through the W-phase winding 3W using the four detected values ​​Id, namely, the detected values ​​IdU, IdV, IdP, and IdN. The control unit 15 may then set the detected values ​​IdU, IdV, IdP, IdN, and the estimated value IcW as normal parameters, or may set the detected values ​​IdU, IdV, IdP, IdN, and the estimated value IcW as normal parameters. Furthermore, if any of the detected values ​​IdU, IdV, IdP, and IdN becomes abnormal, the control unit 15 may set the normal value among the detected values ​​IdU, IdV, IdP, and IdN as the fail-safe parameter. In this case, the control unit 15 may also set the estimated value IcW, in addition to the normal value, as the fail-safe parameter.

[0123] In a configuration in which output current sensors 123 are provided on output lines 14 for only two of the three phases, control unit 15 can calculate detection values ​​Id for two phases but cannot calculate detection value Id for the remaining phase. Even in this configuration, control unit 15 can determine whether an abnormality has occurred in the current paths, such as power lines 5 and 6, output lines 13 and 14, and windings 3U, 3V, and 3W, by using current correlation information. For example, as described above, control unit 15 can determine whether an abnormality has occurred in selector switch 10.

[0124] (Other embodiments) The disclosure in this specification and drawings, etc. is not limited to the exemplified embodiments. The disclosure encompasses the exemplified embodiments and modifications thereto by those skilled in the art. For example, the disclosure is not limited to the combinations of parts and / or elements shown in the embodiments. The disclosure can be implemented in various combinations. The disclosure can have additional parts that can be added to the embodiments. The disclosure encompasses the omission of parts and / or elements from the embodiments. The disclosure encompasses the substitution or combination of parts and / or elements between one embodiment and another embodiment. The disclosed technical scope is not limited to the description of the embodiments. Some disclosed technical scopes are defined by the claims, and should be interpreted as including all modifications within the meaning and scope equivalent to the claims.

[0125] The disclosure in the specification, drawings, etc. is not limited by the claims. The disclosure in the specification, drawings, etc. encompasses the technical ideas described in the claims, and extends to more diverse and broader technical ideas than the technical ideas described in the claims. Therefore, various technical ideas can be extracted from the disclosure in the specification, drawings, etc. without being bound by the claims.

[0126] When an element or layer is referred to as being "on," "coupled," "connected," or "bonded," it may be directly on, coupled, connected, or bonded to the other element or layer, and intervening elements or layers may be present. In contrast, when an element is referred to as being "directly on," "directly coupled," "directly connected," or "directly bonded" to another element or layer, no intervening elements or layers are present. Other language used to describe relationships between elements should be construed in a similar manner (e.g., "between" vs. "directly between," "adjacent" vs. "directly adjacent," etc.).

[0127] As used in this specification, the term "and / or" includes any and all combinations of one or more of the associated listed items, i.e., reference to A and / or B means at least one of A and B, and may include A only, B only, or both A and B.

[0128] Spatially relative terms such as "inside," "outside," "back," "below," "low," "top," "top," and the like are used herein to facilitate the description of one element or feature's relationship to other elements or features, as illustrated. Spatially relative terms may be intended to encompass different orientations of the device during use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures were turned over, elements described as "below" or "directly below" other elements or features would then be oriented "above" the other elements or features. Thus, the term "bottom" can encompass both an orientation of top and bottom. The device may be otherwise oriented (rotated 90 degrees or at other orientations), and the spatially relative descriptors used in this specification would be interpreted accordingly.

[0129] In each of the above embodiments, the drive system 1 does not necessarily have to be provided with the changeover switch 10 on the power supply lines 5 and 6. That is, the drive system 1 does not necessarily have to have the changeover switches 10A and 10B. In this drive system 1, the rotating electric machine 3 is driven in an open connection manner, but is not driven in a star connection manner.

[0130] In each of the above embodiments, whether the output current sensor 123 is provided on the output line 13 or the output line 14 may differ for multiple phases. The output current sensor 123 may be provided on the output line 13 for two of the three phases, and on the output line 14 for the remaining phase. For example, the output current sensors 123U and 123V may be provided on the output line 13, while the output current sensor 123W may be provided on the output line 14.

[0131] In each of the above embodiments, the drive system 1 may have a 3×n rotating electric machine 3. This drive system 1 has a 3×n power conversion circuit 4 to drive the 3×n rotating electric machine 3, where n is a natural number. For example, in the drive system 1, the 3×n power conversion circuit 4 is realized by connecting n three-phase inverters 8, 9 in parallel to the n×3-phase rotating electric machine 3.

[0132] In each of the above embodiments, the wiring 5A, 6A may directly or indirectly connect the inverter 8 and the inverter 9. For example, the wiring 5A, 6A may electrically connect the inverter 9 and the DC power supply 2 without passing through the inverter 8. In this configuration, the wiring 5A, 6A also indirectly connects the inverter 8 and the inverter 9 via the DC power supply 2.

[0133] (Disclosure of technical ideas) This specification discloses multiple technical ideas described in the following multiple clauses. Some clauses may be written in a multiple dependent form, with the subsequent clause referring to the preceding clause as an alternative. Furthermore, some clauses may be written in a multiple dependent form, referring to another multiple dependent clause. These multiple dependent clauses define multiple technical ideas.

[0134] (Technical thought 1) A power conversion device (4) that converts power supplied to a rotating electric machine (3), a first inverter (8) connected to one end of a winding of the rotating electric machine; a second inverter (9) connected to the other end of the winding; a winding current sensor (123) for detecting a current flowing through the winding; a direct current sensor (124) for detecting a current flowing in a direct path (5, 6) connecting the first inverter and the second inverter without passing through the winding; A power conversion device comprising:

[0135] (Technical thought 2) The first inverter is connected to one end of the winding via a first path (8), The second inverter is connected to the other end of the winding via a second path (9), The power conversion device according to Technical Idea 1, wherein the winding current sensor detects the current flowing through the second path out of the first path and the second path as the current flowing through the winding.

[0136] (Technical Thought 3) The first inverter is connected to one end of the winding via a first path (8), The second inverter is connected to the other end of the winding via a second path (9), The power conversion device according to Technical Idea 1, wherein the winding current sensor detects the current flowing through the first path out of the first path and the second path as the current flowing through the winding.

[0137] (Technical Thought 4) a current estimation unit (S102) that estimates each of the current flowing through the winding and the current flowing through the direct path; an abnormality determination unit (S102 to S104) that determines whether an abnormality has occurred in at least one of the winding current sensor and the direct current sensor using the detection results (Id) of the winding current sensor and the direct current sensor and the estimation result (Ic) of the current estimation unit; The power conversion device according to any one of Technical Ideas 1 to 3, comprising:

[0138] (Technical Thought 5) the current estimation unit calculates winding estimates (IcU, IcV, IcW) that estimate currents flowing through the windings and direct estimates (IcP, IcN) that estimate currents flowing through the direct paths; The abnormality determination unit determining whether an abnormality has occurred in the winding current sensor using the winding detection values ​​(IdU, IdV, IdW) that are the detection results of the winding current sensors and the winding estimation values; A power conversion device according to Technical Idea 4, which determines whether an abnormality has occurred in the direct current sensor by using the directly detected values ​​(IdP, IdN) which are the detection results of the direct current sensor and the directly estimated values.

[0139] (Technical Thought 6) The direct route is an upper direct path (5A) connecting the upper arm (8H) of the first inverter and the upper arm (9H) of the second inverter; a lower direct path (6A) connecting the lower arm (8L) of the first inverter and the lower arm (9L) of the second inverter; It contains The winding current sensor a first phase sensor (123U) for detecting a current flowing through a first phase winding (3U) of the three phase windings; A second phase sensor (123V) that detects the current flowing through the second phase winding (3V); a third-phase sensor (124W) that detects the current flowing through the third-phase winding (3W); It contains The direct current sensor an upper sensor (124P) for detecting a current flowing through the upper direct path; a lower sensor (124N) for detecting a current flowing through the lower direct path; 6. The power conversion device according to any one of Technical Concepts 1 to 5, wherein:

[0140] (Technical Thought 7) a current acquisition unit (S101) that acquires detection values ​​(Id) that are detection results of the first phase sensor, the second phase sensor, the third phase sensor, the upper sensor, and the lower sensor; a current estimation unit (S102) that uses detection results from four of the first phase sensor, the second phase sensor, the third phase sensor, the upper sensor, and the lower sensor to calculate an estimated value (Ic) by estimating the remaining detection result; an abnormality determination unit (S103, S104) that determines whether an abnormality has occurred in each of the first phase sensor, the second phase sensor, the third phase sensor, the upper sensor, and the lower sensor, using the detected values ​​and the estimated values ​​of each of the first phase sensor, the second phase sensor, the third phase sensor, the upper sensor, and the lower sensor; The power conversion device according to Technical Idea 6, comprising:

[0141] (Technical Thought 8) The power conversion device according to any one of Technical Ideas 1 to 7, further comprising a changeover switch (10) that is provided in the direct path and connects the power supply unit (2) and the second inverter in a closed state and cuts off the connection between the power supply unit and the second inverter in an open state.

[0142] (Technical Thought 9) A rotating electric machine (3), a power converter (4) that converts the power supplied to the rotating electric machine; A drive system (1) that drives the rotating electric machine using the power conversion device, a three-phase first inverter (8) connected to one end of a winding of the rotating electric machine; a three-phase second inverter (9) connected to the other end of the winding; a winding current sensor (123) for detecting a current flowing through the winding; a direct current sensor (124) for detecting a current flowing in a direct path (5, 6) connecting the first inverter and the second inverter without passing through the winding; A drive system comprising: [Explanation of symbols]

[0143] 1... drive system, 2... DC power supply, 3... rotating electric machine, 3U, 3V, 3W... winding, 4... power conversion circuit, 5A, 5B... wiring, 8, 9... inverter, 10... changeover switch, 13, 14... output line, 123, 123U, 123V, 123W... output current sensor, 124, 124P, 124N... changeover current sensor, Ic, IcU, IcV, IcW, IcP, IcN... estimated value, Id, IdU, IdV, IdW, IdP, IdN... detected value, S101... current acquisition unit, S102... current estimation unit, S102 to S104... abnormality determination unit

Claims

1. A power conversion device (4) that converts power supplied to a rotating electric machine (3), a first inverter (8) connected to one end of a winding of the rotating electric machine; a second inverter (9) connected to the other end of the winding; a winding current sensor (123) for detecting a current flowing through the winding; a direct current sensor (124) for detecting a current flowing in a direct path (5, 6) connecting the first inverter and the second inverter without passing through the winding; A power conversion device comprising:

2. The first inverter is connected to one end of the winding via a first path (8), The second inverter is connected to the other end of the winding via a second path (9), The power conversion device according to claim 1 , wherein the winding current sensor detects, as the current flowing through the winding, a current flowing through the second path out of the first path and the second path.

3. The first inverter is connected to one end of the winding via a first path (8), The second inverter is connected to the other end of the winding via a second path (9), The power conversion device according to claim 1 , wherein the winding current sensor detects, as the current flowing through the winding, a current flowing through the first path out of the first path and the second path.

4. a current estimation unit (S102) that estimates each of a current flowing through the winding and a current flowing through the direct path; an abnormality determination unit (S102 to S104) that determines whether an abnormality has occurred in at least one of the winding current sensor and the direct current sensor using the detection results (Id) of the winding current sensor and the direct current sensor and the estimation result (Ic) of the current estimation unit; The power conversion device according to any one of claims 1 to 3, comprising:

5. the current estimator calculates winding estimates (IcU, IcV, IcW) that estimate currents flowing through the windings and direct estimates (IcP, IcN) that estimate currents flowing through the direct paths; The abnormality determination unit determining whether an abnormality has occurred in the winding current sensor using the winding detection values ​​(IdU, IdV, IdW) that are the detection results of the winding current sensor and the winding estimation values; 5. The power conversion device according to claim 4, wherein whether or not an abnormality has occurred in the direct current sensor is determined using directly detected values ​​(IdP, IdN) that are detection results of the direct current sensor and the directly estimated value.

6. The direct route is an upper direct path (5A) connecting the upper arm (8H) of the first inverter and the upper arm (9H) of the second inverter; a lower direct path (6A) connecting the lower arm (8L) of the first inverter and the lower arm (9L) of the second inverter; It contains The winding current sensor a first phase sensor (123U) for detecting a current flowing through a first phase winding (3U) of the three phase windings; a second phase sensor (123V) for detecting a current flowing through a second phase winding (3V); a third phase sensor (123W) for detecting a current flowing through a third phase winding (3W); It contains The direct current sensor an upper sensor (124P) for detecting a current flowing through the upper direct path; a lower sensor (124N) for detecting a current flowing through the lower direct path; The power conversion device according to any one of claims 1 to 3, comprising:

7. a current acquisition unit (S101) that acquires detection values ​​(Id) that are detection results of the first phase sensor, the second phase sensor, the third phase sensor, the upper sensor, and the lower sensor; a current estimation unit (S102) that uses detection results from four of the first phase sensor, the second phase sensor, the third phase sensor, the upper sensor, and the lower sensor to calculate an estimated value (Ic) of the remaining detection result; an abnormality determination unit (S103, S104) that determines whether an abnormality has occurred in each of the first phase sensor, the second phase sensor, the third phase sensor, the upper sensor, and the lower sensor, using the detected values ​​and the estimated values ​​of each of the first phase sensor, the second phase sensor, the third phase sensor, the upper sensor, and the lower sensor; The power conversion device according to claim 6, further comprising:

8. The power conversion device according to any one of claims 1 to 3, further comprising a changeover switch (10) provided in the direct path, which connects the power supply unit (2) and the second inverter in a closed state and cuts off the connection between the power supply unit and the second inverter in an open state.

9. A rotating electric machine (3), a power conversion device (4) that converts the power supplied to the rotating electric machine; A drive system (1) comprising: a three-phase first inverter (8) connected to one end of a winding of the rotating electric machine; a three-phase second inverter (9) connected to the other end of the winding; a winding current sensor (123) for detecting a current flowing through the winding; a direct current sensor (124) for detecting a current flowing in a direct path (5, 6) connecting the first inverter and the second inverter without passing through the winding; A drive system comprising:

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