Detection device, program, and detection method

Abstract

To provide a detection device capable of suppressing increase in the number of components of an inverter.SOLUTION: A control device 50 is applied to a three-level invertor 30 including first and second capacitors 21, 22 connected in series and switches Su1 to Su4, Sv1 to Sv4, Sw1 to Sw4, and detects failure of at least one of the capacitors 21, 22. The control device 50 includes: an acquisition unit that acquires calculation results based on detection voltages V1r, V2r of voltage sensors 51, 52 and a determination parameter that is at least one of the detection voltages V1r, V2r; and a determination unit that determines whether or not failure has occurred in at least one of capacitors 21, 22 based on the acquired determination parameter.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a detection device and a program. [Background technology]

[0002] Conventionally, a detection device is known that detects a failure in a power storage unit connected to the DC side of an inverter. For example, the detection device detects a failure in the power storage unit based on the output power of a converter that supplies DC power to the power storage unit and the output power of the inverter (see Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2019-140717 A Summary of the Invention [Problem to be solved by the invention]

[0004] There is a need for a new method for detecting a fault in a power storage unit that suppresses an increase in the number of inverter components.

[0005] A main object of the present disclosure is to provide a detection device and a program capable of suppressing an increase in the number of parts of an inverter. [Means for solving the problem]

[0006] The present disclosure relates to A plurality of power storage units connected in series; a switch electrically connected to each of the power storage units and to an armature winding of a rotating electric machine, the detection device being applied to an inverter and detecting a fault in at least one of the power storage units, the inverter is a multilevel inverter that performs switching control of the switch so as to apply to the armature winding either an output voltage of a plurality of voltage levels that can be output from the series-connected array of the power storage units or zero voltage, based on a voltage value of at least one of the power storage units; an acquisition unit that acquires a determination parameter, which is at least one of a calculation result based on the voltage value and the voltage value; a determination unit that determines whether or not the failure has occurred based on the acquired determination parameters; Equipped with.

[0007] In the multilevel inverter, switching control of the switches is performed so that an output voltage of one of a plurality of voltage levels that can be output from the series-connected array of each power storage unit or zero voltage is applied to the armature winding. Here, the switching control in the multilevel inverter is performed based on the voltage value of each power storage unit, for example, in order to control the voltage value of each power storage unit within a control range.

[0008] Therefore, in the present disclosure, the presence or absence of a fault in at least one of the power storage units is determined based on a calculation result based on the voltage value of at least one of the power storage units and a determination parameter that is at least one of the voltage values. In this case, the voltage value of each power storage unit used for switching control can be utilized to detect a fault in at least one of the power storage units. Therefore, fault detection of the power storage units can be performed while suppressing an increase in the number of inverter components. [Brief description of the drawings]

[0009] [Figure 1] 1 is an overall configuration diagram of a control system according to a first embodiment. [Diagram 2] FIG. 2 is a functional block diagram of switching control executed by a control device. [Diagram 3] Diagram showing vector space. [Figure 4] 4 is a time chart showing an example of a transition of the voltage of each capacitor in a normal state; [Diagram 5]5 is a time chart showing an example of a transition of the voltage of each capacitor when a short circuit occurs. [Figure 6] 4 is a flowchart showing a procedure of a failure detection process. [Figure 7] 10 is a flowchart showing a procedure of a failure detection process according to a modification of the first embodiment. [Figure 8] 5 is a time chart showing an example of a voltage transition of each capacitor when a capacitance change fault occurs. [Figure 9] 10 is a flowchart showing the procedure of a failure detection process according to a second embodiment. [Figure 10] 10 is a flowchart showing a procedure of a fault detection process according to a modification of the second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Several embodiments will be described with reference to the drawings. In several embodiments, functionally and / or structurally corresponding and / or associated parts may be given the same reference numerals or reference numerals with different digits of 100 or more. For corresponding and / or associated parts, the description of other embodiments may be referred to.

[0011] First Embodiment DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of a detection device according to the present invention will now be described with reference to the drawings. In this embodiment, the detection device is mounted on an electrically powered vehicle such as an electric vehicle or a hybrid vehicle.

[0012] 1 shows a configuration diagram of a control system mounted on a vehicle. The control system includes a rotating electrical machine 10, a storage battery 20, and an inverter 30.

[0013] The rotating electric machine 10 is an in-vehicle main engine. A rotor of the rotating electric machine 10 is capable of transmitting power to driving wheels of the vehicle. In this embodiment, the rotating electric machine 10 is a three-phase synchronous machine, and includes a U-phase winding 11U, a V-phase winding 11V, and a W-phase winding 11W that are star-connected as stator windings. The phase windings 11U, 11V, and 11W are arranged with a 120° electrical angle offset. The rotating electric machine 10 is, for example, a permanent magnet synchronous machine.

[0014] The storage battery 20 is electrically connected to the rotating electric machine 10 via the inverter 30. The storage battery 20 is a power source that supplies driving power to the rotating electric machine 10. In this embodiment, the storage battery 20 is, for example, a battery pack configured as a series connection of battery cells serving as single cells. As the battery cells, for example, secondary batteries such as lithium ion batteries can be used. The terminal voltage of the storage battery 20 is, for example, 600 to 800 V.

[0015] The inverter 30 is a power conversion circuit that converts DC power supplied from the storage battery 20 into three-phase AC power by switching control and supplies the converted AC power to the rotating electric machine 10. A first capacitor 21 and a second capacitor 22 are provided on the storage battery 20 side of the inverter 30 as a "power storage unit". The first capacitor 21 and the second capacitor 22 are connected in series. The storage battery 20 is connected in parallel to the series connection of the capacitors 21 and 22. In this embodiment, the capacitance of the first capacitor 21 and the capacitance of the second capacitor 22 are set to the same value. The first capacitor 21 and the second capacitor 22 may be provided outside the inverter 30 or may be built into the inverter 30.

[0016] The inverter 30 is a three-level inverter of a neutral point clamp type. The inverter 30 includes U-phase first to fourth switches Su1 to Su4, V-phase first to fourth switches Sv1 to Sv4, W-phase first to fourth switches Sw1 to Sw4, and first to sixth clamp diodes Dc1 to Dc6. In this embodiment, a voltage-controlled semiconductor switching element is used as each of the switches Su1 to Su4, Sv1 to Sv4, and Sw1 to Sw4, and more specifically, an IGBT is used. In this case, the high potential side terminal of each of the switches Su1 to Su4, Sv1 to Sv4, and Sw1 to Sw4 is a collector, and the low potential side terminal is an emitter. In addition, freewheel diodes Du1 to Du4, Dv1 to Dv4, and Dw1 to Dw4 are connected in inverse parallel to each of the switches Su1 to Su4, Sv1 to Sv4, and Sw1 to Sw4.

[0017] The collectors of the first switches Su1, Sv1, and Sw1 of each phase, the positive terminal of the storage battery 20, and a first end of the first capacitor 21 are connected by a positive bus 31 such as a bus bar. The second end of the first capacitor 21 is connected to a first end of the second capacitor 22 via a capacitor neutral point O. The emitters of the fourth switches Su4, Sv4, and Sw4 of each phase, the negative terminal of the storage battery 20, and a second end of the second capacitor 22 are connected by a negative bus 32 such as a bus bar.

[0018] The U-phase first to fourth switches Su1 to Su4 are connected in series with their emitters and collectors connected. A connection point between the U-phase second switch Su2 and the U-phase third switch Su3 is connected to a first end of the U-phase winding 11U. A cathode of a first clamp diode Dc1 is connected to the connection point between the U-phase first switch Su1 and the U-phase second switch Su2, and a cathode of a second clamp diode Dc2 is connected to an anode of the first clamp diode Dc1. A connection point between the U-phase third switch Su3 and the U-phase fourth switch Su4 is connected to an anode of the second clamp diode Dc2.

[0019] The V-phase first to fourth switches Sv1 to Sv4 are connected in series with their emitters and collectors connected. A connection point between the V-phase second switch Sv2 and the V-phase third switch Sv3 is connected to a first end of the V-phase winding 11V. A cathode of a third clamp diode Dc3 is connected to the connection point between the V-phase first switch Sv1 and the V-phase second switch Sv2, and a cathode of a fourth clamp diode Dc4 is connected to an anode of the third clamp diode Dc3. A connection point between the V-phase third switch Sv3 and the V-phase fourth switch Sv4 is connected to an anode of the fourth clamp diode Dc4.

[0020] The W-phase first to fourth switches Sw1 to Sw4 are connected in series with their emitters and collectors connected. A connection point between the W-phase second switch Sw2 and the W-phase third switch Sw3 is connected to a first end of the W-phase winding 11W. A cathode of a fifth clamp diode Dc5 is connected to the connection point between the W-phase first switch Sw1 and the W-phase second switch Sw2, and a cathode of a sixth clamp diode Dc6 is connected to an anode of the fifth clamp diode Dc5. A connection point between the W-phase third switch Sw3 and the W-phase fourth switch Sw4 is connected to an anode of the sixth clamp diode Dc6.

[0021] The connection point between the first clamp diode Dc1 and the second clamp diode Dc2, the connection point between the third clamp diode Dc3 and the fourth clamp diode Dc4, and the connection point between the fifth clamp diode Dc5 and the sixth clamp diode Dc6 are connected to the capacitor neutral point O.

[0022] The control system includes a power switch 40. The power switch 40 is, for example, a relay or a semiconductor switching element. When the power switch 40 is turned on, it electrically connects the storage battery 20 and the inverter 30, and when the power switch 40 is turned off, it electrically disconnects the storage battery 20 and the inverter 30. In this embodiment, the power switch 40 is provided on the positive bus 31 between the positive terminal of the storage battery 20 and the first end of the first capacitor 21. The power switch 40 may be provided on the negative bus 32 between the negative terminal of the storage battery 20 and the second end of the second capacitor 22 in addition to or instead of the positive bus 31.

[0023] The control system includes a discharge circuit 41. The discharge circuit 41 is a circuit for discharging the electric charge accumulated in each of the capacitors 21, 22. The discharge circuit 41 includes a discharge resistor 42 and a discharge switch 43. In this embodiment, the discharge resistor 42 is a series connection of a plurality of resistors. The discharge switch 43 is, for example, a semiconductor switching element. The discharge circuit 41 discharges the electric charge accumulated in each of the capacitors 21, 22 via each of the discharge resistors 42 and the discharge switch 43.

[0024] The control system includes a control device 50, a first voltage sensor 51, a second voltage sensor 52, a phase current sensor 53, a rotation angle sensor 54, and a temperature sensor 55. The first voltage sensor 51 detects the voltage of the first capacitor 21. The second voltage sensor 52 detects the voltage of the second capacitor 22. The phase current sensor 53 detects U-, V-, and W-phase currents flowing through the rotating electric machine 10. Note that it is sufficient for the phase current sensor 53 to detect at least two of the three-phase currents.

[0025] The rotation angle sensor 54 is, for example, a resolver, and detects the electrical angle θe of the rotating electric machine 10. The temperature sensor 55 detects the temperature of the inverter 30. For example, the temperature sensor 55 detects at least one of the temperature of the cooling water that cools the inverter 30 and the temperatures of the switches Su1 to Su4, Sv1 to Sv4, and Sw1 to Sw4. The detection value of the temperature sensor 55 is used for performing fail-safe processing to prevent the inverter 30 from becoming overheated. The detection values ​​of the sensors 51 to 55 are input to the control device 50.

[0026] The control system includes a monitoring unit 56. The monitoring unit 56 detects the terminal voltage, current, temperature, and the like of each battery cell that constitutes the storage battery 20, and monitors the state of the storage battery 20. In this embodiment, the monitoring unit 56 is capable of communicating with the control device 50. The monitoring unit 56 detects the terminal voltage, current, and temperature of the storage battery 20, and these detected values ​​are input to the control device 50.

[0027] The control device 50 is mainly composed of a microcomputer having a CPU and various memories. The functions provided by the microcomputer can be provided by software recorded in a substantial memory device and a computer that executes the software, by software alone, by hardware alone, or by a combination of these. For example, when the microcomputer is provided by an electronic circuit that is hardware, it can be provided by a digital circuit including a large number of logic circuits, or by an analog circuit. For example, the microcomputer executes a program stored in a non-transitory tangible storage medium as a storage unit provided in the microcomputer. The program includes, for example, programs for the processes shown in Figs. 6, 7, 9, 10, etc. By executing the program, a method corresponding to the program is executed. The storage unit is, for example, a non-volatile memory. The program stored in the storage unit can be downloaded and updated via a communication network such as the Internet, for example, OTA (Over The Air), etc.

[0028] For example, when the vehicle is parked, the control device 50 turns off the power switch 40. This electrically disconnects the storage battery 20 from each of the capacitors 21 and 22. When the power switch 40 is turned off, the control device 50 discharges the charge stored in each of the capacitors 21 and 22. For example, the control device 50 turns on the discharge switch 43 to pass a current through a closed circuit including the first and second capacitors 21 and 22, the multiple discharge resistors 42, and the discharge switch 43, thereby discharging the charge stored in each of the capacitors 21 and 22. In addition, for example, the control device 50 controls the switches Su1 to Su4, Sv1 to Sv4, and Sw1 to Sw4 to pass a d-axis current Id (reactive current) through each of the phase windings 11U to 11W, thereby discharging the charge stored in each of the capacitors 21 and 22.

[0029] The control device 50 turns on the power switch 40, for example, when the vehicle starts to travel. When the power switch 40 is turned on, the storage battery 20 charges the capacitors 21, 22. When the capacitors 21, 22 are charged, an output voltage of one of three voltage levels can be output from the series connection of the capacitors 21, 22. This enables the control device 50 to execute switching control of the switches Su1 to Su4, Sv1 to Sv4, and Sw1 to Sw4.

[0030] In the switching control, the control device 50 generates drive commands to turn on and off the switches Su1 to Su4, Sv1 to Sv4, and Sw1 to Sw4. The control device 50 turns on and off the switches Su1 to Su4, Sv1 to Sv4, and Sw1 to Sw4 based on the generated drive commands. The switching control executed by the control device 50 will be described below with reference to FIG. 2.

[0031] The control device 50 includes a command current setting unit 60. A command torque Trq* output from a higher-level control device (not shown) is input to the command current setting unit 60. The command current setting unit 60 sets a d-axis command current Id* and a q-axis command current Iq* in a two-phase rotating coordinate system (dq coordinate system) based on the command torque Trq*.

[0032] The control device 50 includes a two-phase conversion unit 61. The two-phase conversion unit 61 receives the phase currents detected by the phase current sensors 53 and the electrical angle θe detected by the rotation angle sensor 54. The two-phase conversion unit 61 converts the U-, V-, and W-phase currents in a three-phase fixed coordinate system into a d-axis current Idr and a q-axis current Iqr in a two-phase rotating coordinate system (dq coordinate system) based on the input phase currents and electrical angle θe.

[0033] The control device 50 includes d-axis and q-axis deviation calculation units 62a and 62b. The d-axis command current Id* set by the command current setting unit 60 and the d-axis current Idr converted by the two-phase conversion unit 61 are input to the d-axis deviation calculation unit 62a. The d-axis deviation calculation unit 62a calculates a d-axis current deviation ΔId by subtracting the d-axis current Idr from the d-axis command current Id*. The q-axis deviation calculation unit 62b receives the q-axis command current Iq* set by the command current setting unit 60 and the q-axis current Iqr converted by the two-phase conversion unit 61. The q-axis deviation calculation unit 62b calculates a q-axis current deviation ΔIq by subtracting the q-axis current Iqr from the q-axis command current Iq*.

[0034] The control device 50 includes d-axis and q-axis command voltage calculation units 63a and 63b. The d-axis current deviation ΔId calculated by the d-axis deviation calculation unit 62a is input to the d-axis command voltage calculation unit 63a. The d-axis command voltage calculation unit 63a calculates a d-axis command voltage Vd based on the d-axis current deviation ΔId as a manipulated variable for feedback controlling the d-axis current Idr to the d-axis command current Id*.

[0035] The q-axis current deviation ΔIq calculated by the q-axis deviation calculation unit 62b is input to the q-axis command voltage calculation unit 63b. Based on the q-axis current deviation ΔIq, the q-axis command voltage calculation unit 63b calculates a q-axis command voltage Vq as a manipulated variable for feedback controlling the q-axis current Iqr to the q-axis command current Iq*. The feedback control used by the d-axis command voltage calculation unit 63a and the q-axis command voltage calculation unit 63b may be, for example, proportional-integral control.

[0036] The control device 50 includes a fixed coordinate conversion unit 64. The fixed coordinate conversion unit 64 receives a d-axis command voltage Vd calculated by a d-axis command voltage calculation unit 63a, a q-axis command voltage Vq calculated by a q-axis command voltage calculation unit 63b, and an electrical angle θe detected by the rotation angle sensor 54. The fixed coordinate conversion unit 64 converts the d- and q-axis command voltages Vd and Vq in the two-phase rotating coordinate system into α- and β-axis command voltages Vα and Vβ in the two-phase fixed coordinate system based on the d- and q-axis command voltages Vd and Vq and the electrical angle θe.

[0037] The control device 50 includes a modulation unit 65. The α, β-axis command voltages Vα, Vβ converted by the fixed coordinate conversion unit 64 are input to the modulation unit 65. The modulation unit 65 calculates a command voltage vector Vαβ determined by the α, β-axis command voltages Vα, Vβ. The command voltage vector Vαβ is a voltage vector for controlling the control amount of the rotating electric machine 10 to a command value.

[0038] The modulation unit 65 selects the drive state of each of the switches Su1 to Su4, Sv1 to Sv4, and Sw1 to Sw4 based on the command voltage vector Vαβ.

[0039] Specifically, the modulation unit 65 specifies a sector in which the tip of the command voltage vector Vαβ extending from the origin in the vector space exists. The sectors divide the vector space in which the command voltage vector Vαβ can exist into six sectors in terms of the deflection angle of the command voltage vector Vαβ. The deflection angle of the command voltage vector Vαβ is the angle between the command voltage vector Vαβ and the U-phase axis, and is specifically the electrical angle θe. The sign of the electrical angle θe is positive in the leftward (counterclockwise) direction. FIG. 3 shows the first to sixth sectors that divide the vector space into six sectors. In the vector space, the axes of the U, V, and W phases are arranged with an electrical angle shift of 120° each. Each sector is an area sandwiched between the axes of two phases having an electrical angle difference of 60° from each other. In FIG. 3, the range indicating the first sector is hatched.

[0040] The modulator 65 identifies the region in which the tip of the command voltage vector Vαβ exists among the sub-regions that further divide the identified sector into four regions based on the magnitude and deflection angle of the command voltage vector Vαβ (specifically, the angle within the sector). In Fig. 3, the sub-region Rs in which the tip of the command voltage vector Vαβ exists is illustrated by being surrounded by a dashed line.

[0041] The modulation unit 65 selects the drive states of the switches Su1-Su4, Sv1-Sv4, and Sw1-Sw4 based on the identified sector and the sub-area within the sector. As the drive states of the switches Su1-Su4, Sv1-Sv4, and Sw1-Sw4, drive states corresponding to the three vertices constituting the sub-area are selected. For example, when the tip of the command voltage vector Vαβ is in the sub-area Rs of the first sector, one of the following drive states corresponding to the three vertices constituting the sub-area Rs is selected: "HHH", "MMM", "LLL", "MLL", "HMM", "MML", and "HHM".

[0042] The symbols such as "HHM" mentioned above represent the output voltage level of each phase by three voltage levels H, M, L, which correspond to the driving states of the switches Su1 to Su4, Sv1 to Sv4, and Sw1 to Sw4.

[0043] A level H phase voltage is output by electrically connecting the winding of a target phase to the first end of the first capacitor 21. In this case, in the target phase, the first and second switches are turned on and the third and fourth switches are turned off.

[0044] The phase voltage of level M is an output voltage at an intermediate voltage level between levels H and L, and is output by electrically connecting the winding of the target phase to the capacitor neutral point O. In this case, in the target phase, the second and third switches are turned on, and the first and fourth switches are turned off.

[0045] A level L phase voltage is output by electrically connecting the winding of the target phase to the second end of the second capacitor 22. In this case, in the target phase, the third and fourth switches are turned on and the first and second switches are turned off.

[0046] In addition, if the voltage of the storage battery 20 is Vdc and the second end side of the second capacitor 22 is at the reference potential (0 V), the phase voltage of level H is "Vdc", the phase voltage of level M is "Vdc / 2", and the phase voltage of level L is "0".

[0047] For example, "HML" is a driving state of the switches Su1-Su4, Sv1-Sv4, Sw1-Sw4 in which the U-phase voltage is level H, the V-phase voltage is level M, and the W-phase voltage is level L. In "HML," the U-phase first and second switches Su1, Su2, the V-phase second and third switches Sv2, Sv3, and the W-phase third and fourth switches Sw3, Sw4 are turned on, and the U-phase third and fourth switches Su3, Su4, the V-phase first and fourth switches Sv1, Sv4, and the W-phase first and second switches Sw1, Sw2 are turned off.

[0048] The modulation unit 65 sets the appearance period of the drive state of each of the selected switches Su1-Su4, Sv1-Sv4, and Sw1-Sw4 based on the command voltage vector Vαβ. Switching control is performed based on the drive state selected by the modulation unit 65 and the appearance period set for each drive state, thereby controlling the torque of the rotating electric machine 10 to the command torque Trq*.

[0049] Here, in the switching control, the modulation unit 65 acquires the detection voltage V1r of the first voltage sensor 51 and the detection voltage V2r of the second voltage sensor 52. The modulation unit 65 selects the driving state based on the acquired detection voltages V1r and V2r. In detail, "MLL" and "HMM" are located at the same position in the vector space. Also, "MML" and "HHM", "LML" and "MHM", "LMM" and "MHH", "LLM" and "MMH", and "MLM" and "HMH" are similar to "MLL" and "HMM". Hereinafter, "MLL", "MML", "LML", "LMM", "LLM", and "MLM" are referred to as Mid-Lo driving states, and "HMM", "HHM", "MHM", "MHH", "MMH", and "HMH" are referred to as Hi-Mid driving states.

[0050] During the appearance period of the Mid-Lo driving state and the appearance period of the Hi-Mid driving state, the line voltages applied to the windings 11U to 11W are equal, and the voltage at the capacitor neutral point O changes in the opposite direction. Therefore, based on the acquired detection voltages V1r, V2r, the modulation unit 65 selects either the Mid-Lo driving state or the Hi-Mid driving state so that the voltage at the capacitor neutral point O is within the control range.

[0051] Next, a description will be given of the fault detection process for each of the capacitors 21, 22 executed by the control device 50. In this embodiment, the control device 50 corresponds to the "detection device".

[0052] The control device 50 acquires a judgment parameter used in the fault detection process of each of the capacitors 21, 22. In this embodiment, the judgment parameter is a calculation result based on the detected voltages V1r, V2r of each of the voltage sensors 51, 52, specifically, the amount of change over time of the detected voltages V1r, V2r of each of the voltage sensors 51, 52. The control device 50 judges the presence or absence of a fault in each of the capacitors 21, 22 based on the acquired judgment parameter. In this case, the detected voltages V1r, V2r of each of the voltage sensors 51, 52 used for switching control can be utilized to perform the fault detection process of each of the capacitors 21, 22. Therefore, the fault detection of each of the capacitors 21, 22 can be performed while suppressing an increase in the number of components of the inverter 30.

[0053] The fault detection process for each of the capacitors 21 and 22 will be described in detail below.

[0054] Figures 4 and 5 show the transitions of the actual voltage values ​​V1, V2 of the capacitors 21, 22. Figure 4 shows an example of the voltage transitions in a normal state when no failure occurs in the capacitors 21, 22. Figure 5 shows an example of the voltage transitions in a state where a short-circuit failure occurs in the second capacitor 22. In Figures 4 and 5, the voltage value V1 of the first capacitor 21 is indicated by a solid line, and the voltage value V2 of the second capacitor 22 is indicated by a dashed line. Below, first, the voltage transitions of the capacitors 21, 22 in a normal state will be described with reference to Figure 4.

[0055] 4, at time t1, the control device 50 turns on the power switch 40. As a result, the capacitors 21, 22 are charged, and the voltage values ​​V1, V2 of the capacitors 21, 22 increase.

[0056] At time t2, the voltage values ​​V1, V2 of the capacitors 21, 22 reach the predetermined charging value Vc, and charging of the capacitors 21, 22 is completed. The period from time t1 to time t2 is a charging period Tc during which the capacitors 21, 22 are charged. When charging of the capacitors 21, 22 is completed, output voltages of the levels H, M, and L can be output from the series connections of the capacitors 21, 22, and switching control can be performed.

[0057] The period from time t2 to time t3 is a standby period Tw during which switching control is stopped by the control device 50. During the standby period Tw, the voltage values ​​V1, V2 of the capacitors 21, 22 are maintained at the predetermined charging value Vc.

[0058] At time t3, the control device 50 starts to execute switching control. The period from time t3 to time t4 during which the switching control is executed is the execution period Ts. During the execution period Ts, the voltage values ​​V1, V2 of the capacitors 21, 22 change according to the drive states of the switches Su1-Su4, Sv1-Sv4, Sw1-Sw4.

[0059] During the execution period Ts, during a period during which a driving state in which an output voltage of an intermediate voltage level M is output appears (hereinafter, referred to as a first execution period Ts1), at least one of the phase windings 11U to 11W is electrically connected to the capacitor neutral point O. In this case, a current flows out of the capacitor neutral point O, and a current flows into the capacitor neutral point O. Therefore, during the first execution period Ts1, the voltage values ​​V1 and V2 of the capacitors 21 and 22 change. Specifically, when a current flows out of the capacitor neutral point O, the voltage value V1 of the first capacitor 21 increases and the voltage value V2 of the second capacitor 22 decreases. When a current flows into the capacitor neutral point O, the voltage value V1 of the first capacitor 21 decreases and the voltage value V2 of the second capacitor 22 increases. The driving states in which an output voltage of an intermediate voltage level M is output are specifically the Mid-Lo driving state, the Hi-Mid driving state, "HML", "MHL", "LHM", "LMH", "MLH" and "HLM".

[0060] During the execution period Ts, during a period during which a driving state in which an output voltage of the intermediate voltage level M is not output (hereinafter, referred to as a second execution period Ts2), the capacitor neutral point O is not electrically connected to the first end of each of the phase windings 11U to 11W. Therefore, during the second execution period Ts2, the voltage values ​​V1 and V2 of the capacitors 21 and 22 are maintained substantially constant. Specifically, the driving states in which an output voltage of the intermediate voltage level M is not output are "HLL", "HHL", "LHL", "LHH", "LLH", "HLH", "HHH", "MMM", and "LLL". During the periods during which "HHH", "MMM", and "LLL" are output, zero voltage is applied to each of the phase windings 11U to 11W.

[0061] In the first execution period Ts1, the control device 50 selects either the Mid-Lo driving state or the Hi-Mid driving state so that the detected voltages V1r, V2r of the voltage sensors 51, 52 are within the control range. The control range is, for example, a range set near the predetermined charging value Vc, and in FIG. 4, is a range from "Vc-α" to "Vc+α".

[0062] For example, in Fig. 4, the control device 50 executes switching control so that, during the first execution period Ts1, a driving state in which the first capacitor 21 is discharged and the second capacitor 22 is charged, and a driving state in which the first capacitor 21 is charged and the second capacitor 22 is discharged are repeatedly generated. Specifically, the control device 50 selects either the Mid-Lo driving state or the Hi-Mid driving state based on the detection voltages V1r, V2r of the voltage sensors 51, 52. As a result, during the execution period Ts, the voltage values ​​V1, V2 of the capacitors 21, 22 are maintained within the control range. In this embodiment, the standby period Tw and the execution period Ts correspond to an "output period".

[0063] At time t4, the control device 50 turns off the power switch 40. This electrically disconnects the storage battery 20 from the capacitors 21, 22. In this case, the control device 50 causes the charges accumulated in the capacitors 21, 22 to be discharged.

[0064] At time t5, the voltage values ​​V1 and V2 of the capacitors 21 and 22 become equal to or lower than the predetermined discharge value Ve. Here, the predetermined discharge value Ve is 0 V. The period from time t4 to time t5 is a discharge period Td during which the charges stored in the capacitors 21 and 22 are discharged.

[0065] In contrast, when a short circuit occurs in at least one of the capacitors 21, 22, the voltage values ​​V1, V2 of the capacitors 21, 22 change differently from normal. Here, the short circuit is a fault in which the impedance of the capacitors 21, 22 decreases, and the charge stored in the capacitors 21, 22 becomes more likely to escape. For example, when a short circuit occurs in the capacitors 21, 22, the impedance of the capacitors 21, 22 decreases to 1 / 1000 to 1 / 100 or 1 / 1000 to 1 / 100 of normal.

[0066] A case where a short-circuit failure occurs in the second capacitor 22 will be described below with reference to Fig. 5. In Fig. 5, the same reference numerals are used for the configurations shown in Fig. 4 for convenience.

[0067] When a short circuit occurs in the second capacitor 22, a leakage current occurs in the second capacitor 22, and a current flows out from the capacitor neutral point O via the second capacitor 22. In this case, even during the standby period Tw and the second execution period Ts2, the voltage value V1 of the first capacitor 21 increases and the voltage value V2 of the second capacitor 22 decreases.

[0068] For example, in FIG. 5, the voltage value V1 of the first capacitor 21 during the standby period Tw rises by ΔV1 from the predetermined charging value Vc, and the voltage value V2 of the second capacitor 22 during the standby period Tw falls by ΔV2 from the predetermined charging value Vc. Also, during the second execution period Ts2 after time t3, the voltage value V1 of the first capacitor 21 rises and the voltage value V2 of the second capacitor 22 falls. In this case, in the switching control, the modulation unit 65 intermittently selects a driving state in which the first capacitor 21 is discharged and the second capacitor 22 is charged in order to bring the voltage values ​​V1 and V2 of the capacitors 21 and 22 closer to the predetermined charging value Vc during the first execution period Ts1. Therefore, during the first execution period Ts1, the voltage value V1 of the first capacitor 21 falls and the voltage value V2 of the second capacitor 22 rises.

[0069] Furthermore, when a short circuit occurs in the first capacitor 21, a leakage current occurs in the first capacitor 21, and a current flows into the capacitor neutral point O via the first capacitor 21. In this case, even during the standby period Tw and the second execution period Ts2, the voltage value V1 of the first capacitor 21 decreases and the voltage value V2 of the second capacitor 22 increases. In this case, the modulation unit 65 intermittently selects, in switching control, a driving state in which the first capacitor 21 is charged and the second capacitor 22 is discharged during the first execution period Ts1.

[0070] In this embodiment, the control device 50 acquires determination parameters for the waiting period Tw and the execution period Ts.

[0071] Specifically, the judgment parameter for the standby period Tw is the amount of change over time of the detected voltages V1r, V2r of the voltage sensors 51, 52 during the standby period Tw. For example, the control device 50 calculates the amount of change over time of the detected voltages V1r, V2r during the standby period Tw based on the detected voltages V1r, V2r of the voltage sensors 51, 52 at times t2, t3 and the length of the standby period Tw from time t2 to time t3. In this case, the control device 50 acquires the calculation result of the amount of change over time of the detected voltages V1r, V2r as the judgment parameter.

[0072] The judgment parameter for the execution period Ts is the amount of change over time of the detected voltages V1r, V2r of the voltage sensors 51, 52 during the second execution period Ts2. For example, the control device 50 calculates the amount of change over time of the detected voltages V1r, V2r during the second execution period Ts2 based on the detected voltages V1r, V2r of the voltage sensors 51, 52 at the start and end timings of the consecutive second execution periods Ts2 and the length of the consecutive second execution periods Ts2. In this case, the control device 50 acquires the calculation result of the amount of change over time of the detected voltages V1r, V2r as the judgment parameter.

[0073] The control device 50 judges whether or not a short circuit fault has occurred in each of the capacitors 21, 22 based on the acquired judgment parameters. For example, when the control device 50 acquires the amount of change over time of the detected voltages V1r, V2r of the voltage sensors 51, 52 in the waiting period Tw or the second execution period Ts2 as the judgment parameters, the control device 50 judges that a short circuit fault has occurred in at least one of the capacitors 21, 22, on condition that the magnitude of the acquired amount of change over time is greater than a predetermined amount of change. The predetermined amount of change is set, for example, according to the amount of decrease in impedance of each of the capacitors 21, 22 that occurs when a short circuit fault occurs.

[0074] 6 shows the procedure of the failure detection process executed by the control device 50. This control is repeatedly executed at a predetermined cycle, for example, after the power switch 40 is turned on and a charging period Tc has elapsed.

[0075] In step S10, it is determined whether or not switching control is being executed. If the determination in step S10 is negative, the process proceeds to step S11. On the other hand, if the determination in step S10 is positive, the process proceeds to step S13.

[0076] In step S11, a judgment parameter for the standby period Tw is acquired. Here, the amount of change over time of the detected voltages V1r, V2r of the voltage sensors 51, 52 is calculated based on the detected voltages V1r, V2r of the voltage sensors 51, 52 and the length of the standby period Tw, and the calculated amount of change over time of the detected voltages V1r, V2r is acquired as a judgment parameter. In step S12, the presence or absence of a short-circuit fault in each of the capacitors 21, 22 is judged based on the judgment parameter acquired in step S11. If a negative judgment is made in step S12, it is judged that a short-circuit fault has not occurred in each of the capacitors 21, 22, and this process is terminated.

[0077] In step S13, a judgment parameter for the second execution period Ts2 is acquired. Here, the amount of change over time of the detected voltages V1r, V2r of the voltage sensors 51, 52 is calculated based on the detected voltages V1r, V2r of the voltage sensors 51, 52 and the length of the second execution period Ts2. The calculated amount of change over time of the detected voltages V1r, V2r is acquired as a judgment parameter. In this embodiment, the processes of steps S11 and S13 correspond to an "acquisition unit."

[0078] In step S14, based on the determination parameters acquired in the process of step S13, it is determined whether or not a short-circuit fault has occurred in each of the capacitors 21, 22. If a negative determination is made in step S14, it is determined that a short-circuit fault has not occurred, and this process is terminated.

[0079] If the determination in steps S12 and S14 is affirmative, the process proceeds to step S15. In step S15, it is determined that a short-circuit fault has occurred in at least one of the capacitors 21 and 22. In this embodiment, the processes in steps S12, S14, and S15 correspond to a "determination unit."

[0080] In this embodiment, the judgment parameters for the standby period Tw and the second execution period Ts2 are acquired. When a short-circuit fault occurs in at least one of the capacitors 21 and 22, an abnormality occurs in the voltage values ​​V1 and V2 of the capacitors 21 and 22 in the standby period Tw and the execution period Ts. Therefore, based on the acquired judgment parameters for the standby period Tw and the second execution period Ts2, it is possible to accurately judge whether or not a short-circuit fault has occurred in each of the capacitors 21 and 22.

[0081] Here, when a short circuit occurs in at least one of the capacitors 21, 22, even if the switching control is stopped after the charging period Tc, the voltage of each of the capacitors 21, 22 changes due to the occurrence of leakage current in the capacitor in which the short circuit occurs. For the same reason, even if the output voltage of the intermediate voltage level M is not output during the switching control, the voltage of each of the capacitors 21, 22 changes. Therefore, in this embodiment, the time change amount of the detected voltages V1r, V2r of each of the voltage sensors 51, 52 in the waiting period Tw and the second execution period Ts2 is used as a judgment parameter. This makes it possible to accurately grasp the abnormality of the voltage transition of each of the capacitors 21, 22 caused by the occurrence of the short circuit. Therefore, it is possible to realize a configuration suitable for judging the presence or absence of the occurrence of the short circuit.

[0082] In step S16, a notification process is performed. In the notification process, the occurrence of a short-circuit fault in at least one of the capacitors 21, 22 is notified to at least one of the upper control device and the user. For example, when the upper control device receives a notification from the control device 50 that a short-circuit fault has occurred, the upper control device takes measures such as setting a limit on the command torque Trq*. As a notification to the user, it is possible to display the occurrence of a short-circuit fault on a display device provided in the vehicle, such as an instrument panel or a car navigation system, or to display the occurrence of a short-circuit fault on a server outside the vehicle or a mobile terminal, such as a smartphone.

[0083] In the process of step S15, it may be possible to determine which of the capacitors 21, 22 has a short-circuit failure based on the acquired judgment parameters. For example, it may be possible to determine that the short-circuit failure has occurred in one of the capacitors 21, 22, whose detected voltage has decreased, based on the amount of change over time of the detected voltages V1r, V2r of the voltage sensors 51, 52 during the waiting period Tw. This allows the notification process to be performed appropriately. For example, in a vehicle repair shop, it is possible to accurately notify a worker repairing the vehicle of the location of the failure.

[0084] <Modification of the first embodiment> Instead of the amount of change over time in the detected voltages V1r, V2r of the voltage sensors 51, 52, the voltage values ​​V1, V2 of the capacitors 21, 22 may be used as the determination parameters.

[0085] Specifically, in step S11 of FIG. 6, the detection voltages V1r, V2r of the voltage sensors 51, 52 during the standby period Tw may be acquired as the judgment parameters. In step S12, the presence or absence of a short circuit failure in each of the capacitors 21, 22 may be judged based on the acquired detection voltages V1r, V2r. For example, when the detection voltages V1r, V2r at the end timing of the standby period Tw are values ​​outside the control range, it may be judged that a short circuit failure has occurred in at least one of the capacitors 21, 22. In this case, in step S15, it may be judged which of the capacitors 21, 22 has a short circuit failure based on a comparison of the acquired detection voltages V1r, V2r. For example, it may be judged that a short circuit failure has occurred in the capacitor with the lower detection voltage among the capacitors 21, 22.

[0086] As the judgment parameter, the amount of change in the detected voltages V1r, V2r of the voltage sensors 51, 52 over time during the first execution period Ts1 may be used instead of the amount of change in the detected voltages V1r, V2r of the voltage sensors 51, 52 over time during the second execution period Ts2. In this case, for example, in the process of step S13 in FIG. 6, the amount of change in the detected voltages V1r, V2r of the voltage sensors 51, 52 over time during the first execution period Ts1 may be calculated based on the detected voltages V1r, V2r of the voltage sensors 51, 52 at the start and end timings of the consecutive first execution period Ts1 and the length of the consecutive second execution period Ts2. Then, the calculation result of the amount of change in the detected voltages V1r, V2r over time may be acquired as the judgment parameter.

[0087] In step S14, the presence or absence of a short-circuit fault in each of the capacitors 21, 22 may be determined based on the amount of change over time of the detected voltages V1r, V2r of the voltage sensors 51, 52 that have been acquired.

[0088] For example, if a short circuit occurs in at least one of the capacitors 21, 22 and the function of storing charge of the failed capacitor is reduced, the voltage values ​​V1, V2 of the capacitors 21, 22 are more likely to change than normal when a current flows in or out through the capacitor neutral point O. In this case, during the first execution period Ts1, the amount of change over time in the voltage values ​​V1, V2 of the capacitors 21, 22 is greater than normal.

[0089] Therefore, in step S14, on the condition that the magnitude of the amount of change over time of each of the detected voltages V1r, V2r in the acquired first execution period Ts1 is larger than that in a normal state, it may be determined that a short-circuit fault has occurred in at least one of the capacitors 21, 22. The amount of change over time of each of the detected voltages V1r, V2r in a normal state may be a preset value, or a value calculated before the current control cycle.

[0090] According to the present embodiment, it is possible to accurately grasp the abnormality of the voltage transition in the first execution period Ts1 caused by the occurrence of a short circuit fault, and therefore it is possible to realize a configuration suitable for determining whether or not a short circuit fault has occurred.

[0091] As a judgment parameter for the first execution period Ts1, the drive states of the switches Su1-Su4, Sv1-Sv4, and Sw1-Sw4 selected in accordance with the detected voltages V1r, V2r may be used instead of the amount of change over time of the detected voltages V1r, V2r of the voltage sensors 51, 52. In this case, in the process of step S13 in Fig. 6, the calculation result of the calculation to select the drive state for the first execution period Ts1 by the modulator 65 may be acquired as the judgment parameter.

[0092] In step S14, the presence or absence of a short-circuit fault in each of the capacitors 21, 22 may be determined based on the drive states of the switches Su1 to Su4, Sv1 to Sv4, and Sw1 to Sw4 during the acquired first execution period Ts1.

[0093] Here, when a short circuit fault occurs in at least one of the capacitors 21, 22, the direction of the current flowing through the capacitor neutral point O may be biased to one direction. For example, when a short circuit fault occurs in the second capacitor 22, the direction of the current flowing through the capacitor neutral point O may be biased to the direction in which the current flows out from the capacitor neutral point O. In this case, during the first execution period Ts1, the modulation unit 65 may biasedly select, from the Mid-Lo driving state and the Hi-Mid driving state, the driving state in which the first capacitor 21 is discharged and the second capacitor 22 is charged, compared to the normal state.

[0094] Therefore, in step S14, it may be determined whether or not one of the driving states in which the first capacitor 21 is discharged and the second capacitor 22 is charged, and the driving state in which the first capacitor 21 is charged and the second capacitor 22 is discharged, appears abnormally more than the other, during the first execution period Ts1. For example, when only one of the driving states in which the first capacitor 21 is discharged and the second capacitor 22 is charged, and the driving state in which the first capacitor 21 is charged and the second capacitor 22 is discharged, is selected intermittently during the first execution period Ts1, it may be determined that the driving states appear abnormally more than the other. In this case, the process may proceed to step S15, and it may be determined that a short-circuit fault has occurred in one of the capacitors 21 and 22. In addition, in the processing of step S15, based on the driving states of each switch Su1 to Su4, Sv1 to Sv4, Sw1 to Sw4 during the acquired first execution period Ts1, it may be determined that a short-circuit fault has occurred in one of the capacitors 21, 22 that is abnormally charged unevenly.

[0095] According to the present embodiment, it is possible to accurately grasp the abnormality in the switching state during the first execution period Ts1 caused by the occurrence of a short circuit fault, and therefore it is possible to realize a configuration suitable for determining whether or not a short circuit fault has occurred.

[0096] In the switching control, the calculation for selecting either the Mid-Lo driving state or the Hi-Mid driving state is performed based on the detected voltages V1r, V2r of the voltage sensors 51, 52. Therefore, the process for detecting a short-circuit fault in the above-mentioned steps S13, S14 can be performed based on the detected voltages V1r, V2r of the voltage sensors 51, 52.

[0097] As shown in Fig. 7, a process may be added that is executed when it is determined that no short-circuit fault has occurred based on the voltage values ​​V1 and V2 of the capacitors 21 and 22. Note that in Fig. 7, the same reference numerals are used for the configurations shown in Fig. 6 for convenience.

[0098] If the determination in steps S12 and S14 is negative, the process proceeds to step S17. In step S17, the output power PI of the inverter 30 and the output power PB of the storage battery 20 are acquired. For example, the drive power of the rotating electric machine 10 may be acquired as the output power PI of the inverter 30. For example, the drive power of the rotating electric machine 10 may be calculated based on the detection value of the phase current sensor 53 and the detection value of the rotation angle sensor 54. Also, for example, a value calculated based on the terminal voltage and current of the storage battery 20 input from the monitoring unit 56 may be acquired as the output power PB of the storage battery 20.

[0099] Here, if a short-circuit fault occurs in at least one of the capacitors 21, 22, the output power PB of the storage battery 20 (i.e., the input power of the inverter 30) may become greater than the output power PI of the inverter 30. Therefore, in step S18, it is determined whether or not the differential power obtained by subtracting the output power PI of the inverter 30 from the output power PB of the storage battery 20 is greater than a predetermined power value Pa. If a positive determination is made in step S18, the process proceeds to step S15. On the other hand, if a negative determination is made in step S18, it is determined that no short-circuit fault has occurred, and this process ends. The predetermined power value Pa is set, for example, according to the amount of decrease in impedance of each of the capacitors 21, 22.

[0100] According to this embodiment, it is possible to detect short-circuit failures in the capacitors 21, 22 by utilizing the detection values ​​of the phase current sensor 53 and the rotation angle sensor 54 used for switching control, and the detection value of the monitoring unit 56 used for monitoring the storage battery 20. Therefore, it is possible to improve the accuracy of detecting short-circuit failures in the capacitors 21, 22 while suppressing an increase in the number of parts of the inverter 30.

[0101] <Second embodiment> The second embodiment will be described below with reference to the drawings, focusing on the differences from the first embodiment. In this embodiment, in the fault detection process, a capacitance change fault, which is an abnormality in which the capacitance of each of the capacitors 21, 22 increases or decreases, is detected instead of a short-circuit fault of each of the capacitors 21, 22. For example, a capacitance change fault occurs due to deterioration of each of the capacitors 21, 22.

[0102] Fig. 8 shows an example of a voltage transition when a capacitance change fault occurs in which the capacitance of the second capacitor 22 decreases. In Fig. 8, the same reference numerals are used for the components shown in Fig. 4 for convenience.

[0103] For example, when the capacitance of the second capacitor 22 decreases due to the occurrence of a capacitance change failure, the voltage value V2 when charge is accumulated in the second capacitor 22 becomes higher than when no capacitance change failure occurs. In Fig. 8, the voltage value V2 of the second capacitor 22 at the end timing of the charging period Tc is higher than the predetermined charging value Vc. Therefore, after the charging period Tc, a differential voltage ΔV12 between the voltage value V2 of the second capacitor 22 and the voltage value V1 of the first capacitor 21 is generated.

[0104] Even if a capacitance change failure occurs in the first capacitor 21 and the capacitance of the first capacitor 21 decreases, the voltage value V1 increases when charge is accumulated in the first capacitor 21. Therefore, similar to the case where the capacitance of the second capacitor 22 decreases, a differential voltage ΔV12 occurs after the charging period Tc.

[0105] Furthermore, a capacitance change failure may occur in which the capacitance increases in one of the capacitors 21, 22. In this case, the voltage values ​​V1, V2 when charge accumulates in the failed one of the capacitors 21, 22 are lower than when the capacitance change failure does not occur. Therefore, a differential voltage ΔV12 occurs after the charging period Tc, similar to when a capacitance change failure occurs in which the capacitance decreases.

[0106] 9 shows the procedure of the failure detection process executed by the control device 50. This control is repeatedly executed at a predetermined cycle.

[0107] In step S20, the power switch 40 is switched. In this embodiment, the power switch 40 is switched from off to on. This starts the charging period Tc.

[0108] In step S21, a judgment parameter for the charging period Tc is acquired. In this embodiment, the judgment parameter for the charging period Tc is a differential voltage ΔV12 between the detected voltages V1r, V2r of the voltage sensors 51, 52. For example, the differential voltage ΔV12 is calculated based on the detected voltages V1r, V2r of the voltage sensors 51, 52 at the end timing of the charging period Tc. In this case, the calculation result of the differential voltage ΔV12 is acquired as the judgment parameter. Note that the differential voltage ΔV12 may be calculated based on the detected voltages V1r, V2r of the voltage sensors 51, 52 during the waiting period Tw or the charging period Tc.

[0109] In step S22, it is determined whether or not a capacitance change fault has occurred in each of the capacitors 21, 22 based on the determination parameters acquired by the process of step S21. For example, if the acquired differential voltage ΔV12 is greater than a predetermined differential value, it is determined that a capacitance change fault has occurred in at least one of the capacitors 21, 22. The predetermined differential value is set according to the degree of change in capacitance that occurs in the event of a capacitance change fault. If a negative determination is made in step S22, it is determined that a capacitance change fault has not occurred, and this process is terminated. On the other hand, if a positive determination is made in step S22, the process proceeds to step S23.

[0110] In step S23, it is determined that a capacitance change fault has occurred in at least one of the capacitors 21, 22. In step S24, a notification process is performed. The process of step S24 is similar to the process of step S16 in FIG. 6 described in the first embodiment. In this embodiment, the process of step S21 corresponds to an "acquisition unit", and the processes of steps S22 and S23 correspond to a "determination unit".

[0111] In this embodiment, a judgment parameter for the charging period Tc is acquired. When a capacitance change fault occurs in at least one of the capacitors 21, 22, an abnormality occurs in the voltage values ​​V1, V2 of the capacitors 21, 22 during the charging period Tc. Therefore, based on the judgment parameter for the charging period Tc acquired, it is possible to accurately judge whether or not a capacitance change fault has occurred in each of the capacitors 21, 22.

[0112] Here, when a capacitance change fault occurs in either one of the capacitors 21, 22, a differential voltage ΔV12 between the voltage values ​​V1, V2 of the capacitors 21, 22 is generated. Therefore, in this embodiment, the differential voltage ΔV12 between the detected voltages V1r, V2r of the voltage sensors 51, 52 at the end timing of the charging period Tc is used as a judgment parameter. This makes it possible to accurately grasp the abnormality of the voltage values ​​V1, V2 of the capacitors 21, 22 caused by the occurrence of a capacitance change fault. Therefore, a configuration suitable for judging the occurrence or non-occurrence of a capacitance change fault can be realized.

[0113] <Modification of the second embodiment> Instead of the differential voltage ΔV12 between the detected voltages V1r, V2r of the voltage sensors 51, 52, the voltage values ​​V1, V2 of the capacitors 21, 22 may be used as the determination parameter.

[0114] 9, the detected voltages V1r, V2r of the voltage sensors 51, 52 during the charging period Tc may be acquired as the determination parameters. In step S22, the presence or absence of a capacitance change fault in each of the capacitors 21, 22 may be determined based on the acquired detected voltages V1r, V2r of the voltage sensors 51, 52. For example, when at least one of the detected voltages V1r, V2r during the charging period Tc is outside the control range, it may be determined that a capacitance change fault has occurred in at least one of the capacitors 21, 22.

[0115] In step S23, it may be determined that the capacitance change fault has occurred in the capacitor whose detected voltage V1r, V2r is outside the control range, among the capacitors 21, 22. This allows the notification process in step S24 to be performed appropriately.

[0116] The processes of steps S21, S22, and S23 described above may be executed using the detected voltages V1r and V2r of the voltage sensors 51 and 52 during the standby period Tw.

[0117] When a capacity change fault occurs, it is considered that the length of the charging period Tc and the length of the discharging period Td change from the normal state. Therefore, at least one of the length of the charging period Tc and the length of the discharging period Td may be used as the judgment parameter.

[0118] 9, the length of the charging period Tc may be calculated based on the voltages V1r and V2r detected after the power switch 40 is turned on by the process of step S20. Then, the calculation result for the length of the charging period Tc may be obtained as a judgment parameter.

[0119] In step S22, it may be determined whether or not a capacitance change fault has occurred in each of the capacitors 21, 22 based on the length of the acquired charging period Tc. For example, if there is an abnormality such that the length of the acquired charging period Tc is longer or shorter than the charging period Tc under normal conditions, it may be determined that a capacitance change fault has occurred in at least one of the capacitors 21, 22. The length of the charging period Tc under normal conditions may be a preset value, or a value calculated before the current control cycle.

[0120] In step S23, depending on whether the length of the acquired charging period Tc is longer or shorter than the charging period Tc in normal operation, it may be determined that a failure in which the capacitance decreases or a failure in which the capacitance increases has occurred. For example, when it is determined that the length of the acquired charging period Tc is longer than the charging period Tc in normal operation, it may be determined that a failure in which the capacitance increases has occurred. Also, for example, when it is determined that the length of the acquired charging period Tc is shorter than the charging period Tc in normal operation, it may be determined that a failure in which the capacitance decreases has occurred. This allows the notification process in step S24 to be performed appropriately. For example, depending on whether a failure in which the capacitance decreases or a failure in which the capacitance increases has occurred, the action taken by the upper control device may be changed.

[0121] According to the present embodiment, it is possible to accurately grasp the change in the length of the charging period Tc caused by the occurrence of a capacitance change fault based on the acquired length of the charging period Tc, and therefore it is possible to realize a configuration suitable for determining whether or not a capacitance change fault has occurred.

[0122] It is possible to use the length of the discharging period Td as the judgment parameter instead of the length of the charging period Tc. In this case, in the process of step S20, the power switch 40 is switched from on to off. In step S21, the length of the discharging period Td is calculated based on the detected voltages V1r, V2r of the voltage sensors 51, 52 after the power switch 40 is turned off. Then, the calculation result for the length of the discharging period Td is obtained as the judgment parameter. The processes of steps S22 to S24 may be performed in the same manner as in the case where the length of the charging period Tc is used.

[0123] As shown in Fig. 10, the fault detection process may be executed to determine whether a capacitance increase fault or a capacitance decrease fault has occurred in either one of the capacitors 21, 22, and to determine in which of the capacitors 21, 22 the determined capacitance increase fault or capacitance decrease fault has occurred. Note that in Fig. 10, the same reference numerals are used for the configurations shown in Fig. 9 for convenience.

[0124] In step S20, the power switch 40 is switched from off to on. In step S21, the length of the charging period Tc is obtained as a first determination parameter Ta, and the detected voltages V1r, V2r of the voltage sensors 51, 52 during the charging period Tc are obtained as second determination parameters.

[0125] In step S30, it is determined whether the first determination parameter Ta acquired in the process of step S21 is abnormal, such as being longer or shorter than normal. If the determination in step S30 is negative, it is determined that a capacity change fault has not occurred, and this process ends. On the other hand, if the determination in step S30 is positive, the process proceeds to step S31.

[0126] In step S31, it is determined whether the acquired first determination parameter Ta is abnormal and is longer than normal. For example, it is determined whether the first determination parameter Ta is longer than a predetermined value. For example, the predetermined value is set to the upper limit of an expected range for the length of the charging period Tc in normal times. If an affirmative determination is made in step S31, the process proceeds to step S32.

[0127] In step S32, the detected voltages V1r, V2r of the voltage sensors 51, 52 acquired in the process of step S21 are compared. If it is determined that the detected voltage V1r of the first voltage sensor 51 is higher than the detected voltage V2r of the second voltage sensor 52, the process proceeds to step S33. On the other hand, if it is determined that the detected voltage V1r of the first voltage sensor 51 is equal to or lower than the detected voltage V2r of the second voltage sensor 52, the process proceeds to step S34.

[0128] In step S33, it is determined that a failure has occurred that causes an increase in the capacitance of the second capacitor 22. In step S34, it is determined that a failure has occurred that causes an increase in the capacitance of the first capacitor 21.

[0129] If a negative determination is made in step S31, it is determined that the acquired first determination parameter Ta is abnormal and shorter than normal, and the process proceeds to step S35. In step S35, the same process as in step S32 is performed. If a positive determination is made in step S35, the process proceeds to step S36. On the other hand, if a negative determination is made in step S35, the process proceeds to step S37.

[0130] In step S36, it is determined that a failure has occurred that reduces the capacitance of first capacitor 21. In step S37, it is determined that a failure has occurred that reduces the capacitance of second capacitor 22. In this embodiment, the processes in steps S30 to S37 correspond to a "determination unit."

[0131] In the above-described failure detection process, the first determination parameter Ta can also be set as the length of the discharge period Td.

[0132] <Other embodiments> Each of the above embodiments may be modified as follows.

[0133] In each of the above-described embodiments, it is sufficient that a failure detection process is executed to detect a failure in either one of the capacitors 21, 22.

[0134] In switching control, the modulation unit 65 may acquire either the detected voltages V1r, V2r of the voltage sensors 51, 52, and select either the Mid-Lo driving state or the Hi-Mid driving state based on the acquired detected voltage so that the voltage of the capacitor neutral point O is within the control range. Even in this case, the control device 50 can utilize the detected voltage of the voltage sensor used for switching control in the fault detection process.

[0135] The voltage values ​​V1, V2 of the capacitors 21, 22 used in the switching control and fault detection process are not limited to the detected voltages V1r, V2r of the voltage sensors 51, 52, but may be values ​​calculated from detected values ​​of other sensors. For example, the voltage value of the other capacitor may be calculated based on the detected voltage of one of the voltage sensors 51, 52, and the calculated value may be used in the switching control and fault detection process. Also, for example, the voltage values ​​V1, V2 of the capacitors 21, 22 may be calculated based on the detected value of the phase current sensor 53 and the capacitance of each of the capacitors 21, 22, and the calculated value may be used in the switching control and fault detection process.

[0136] The capacitance of each of the capacitors 21, 22 may change depending on the temperature. Therefore, the predetermined charging value Vc used to define the control range and the predetermined value used in the process of step S31 in Fig. 10 may be corrected based on the detection value of the temperature sensor 55. This makes it possible to improve the accuracy of detecting capacitance change faults in each of the capacitors 21, 22 by utilizing the detection value of the temperature sensor 55 used to perform the fail-safe process.

[0137] The control device 50 may have a function of executing both a fault detection process for detecting a short-circuit fault and a fault detection process for detecting a capacitance change fault.

[0138] The semiconductor switches constituting the inverter are not limited to IGBTs, but may be, for example, N-channel MOSFETs. In this case, the high-potential terminal of the switch is the drain, and the low-potential terminal is the source. Each switch also has a body diode.

[0139] The inverter is not limited to the inverter shown in FIG. 1, but may be, for example, a T-type three-level inverter.

[0140] The power storage unit connected to the inverter is not limited to a capacitor, and may be a chargeable and dischargeable storage battery (for example, a small-capacity storage battery).

[0141] The rotating electric machine is not limited to one in which the windings of each phase are star-connected, and may be one in which the windings are delta-connected.

[0142] The inverter, the rotating electric machine, and the control device may be mounted on a moving object such as an aircraft or a ship, without being limited to a vehicle. If the moving object is an aircraft, the rotating electric machine serves as the power source for the aircraft to fly, and if the moving object is a ship, the rotating electric machine serves as the power source for the ship to navigate. Furthermore, the inverter, the rotating electric machine, and the control device may be mounted on a moving object such as an aircraft, without being limited to a vehicle.

[0143] The multilevel inverter is not limited to a three-level inverter, but may be an inverter with four or more levels. In this case, the control device may execute a fault detection process to detect a fault in at least one of three or more capacitors provided in the inverter.

[0144] The control device and the method described in the present disclosure may be realized by a special-purpose computer provided by configuring a processor and a memory programmed to execute one or more functions embodied in a computer program. Alternatively, the control device and the method described in the present disclosure may be realized by a special-purpose computer provided by configuring a processor with one or more dedicated hardware logic circuits. Alternatively, the control device and the method described in the present disclosure may be realized by one or more special-purpose computers configured by a combination of a processor and a memory programmed to execute one or more functions and a processor configured with one or more hardware logic circuits. In addition, the computer program may be stored in a computer-readable non-transitory tangible recording medium as instructions executed by the computer.

[0145] Characteristic configurations extracted from the above-described embodiments will be described below. [Configuration 1] a plurality of power storage units (21, 22) connected in series; A detection device (50) is applied to an inverter (30) including switches (Su1-Su4, Sv1-Sv4, Sw1-Sw4) electrically connected to the power storage units and armature windings (11U, 11V, 11W) of a rotating electric machine (10), and detects a fault in at least one of the power storage units, the inverter is a multilevel inverter that performs switching control of the switch so as to apply to the armature winding either an output voltage of a plurality of voltage levels that can be output from the series-connected array of the power storage units or zero voltage, based on a voltage value of at least one of the power storage units; an acquisition unit that acquires a determination parameter, which is at least one of a calculation result based on the voltage value and the voltage value; a determination unit that determines whether or not the failure has occurred based on the acquired determination parameters; A detection device comprising: [Configuration 2] 2. The detection device according to configuration 1, wherein the acquisition unit acquires the determination parameter during an output period during which the series-connected units of the power storage units can output output voltages of the respective voltage levels. [Configuration 3] 3. The detection device according to configuration 2, wherein the determination parameter is a time change amount of the voltage value when the switching control is stopped. [Configuration 4] The detection device according to configuration 2 or 3, wherein the determination parameter is an amount of change over time in the voltage value when an output voltage of an intermediate voltage level among the voltage levels is not being output during the switching control. [Configuration 5] The detection device according to any one of configurations 2 to 4, wherein the judgment parameter is a time change amount of the voltage value when an output voltage of an intermediate voltage level among the voltage levels is output during the switching control. [Configuration 6] The detection device according to any one of configurations 2 to 5, wherein the judgment parameter is at least one of the voltage value when an output voltage of an intermediate voltage level among the voltage levels is output during the switching control, and a drive state of the switch selected according to the voltage value. [Configuration 7] a power source (20) that supplies driving power to the rotating electric machine is connected to the series connection of each of the power storage units; a power switch (40) is provided between the power source and the series connection of each of the power storage units, The detection device according to any one of configurations 1 to 6, wherein the acquisition unit acquires the judgment parameter for at least one of a charging period from when the power switch is turned on until the voltage value reaches a predetermined charging value, a period during which the voltage value is maintained during the charging period, and a discharging period from when the power switch is turned off until the voltage value becomes equal to or lower than a predetermined discharging value. [Configuration 8] 8. The detection device according to claim 7, wherein the determination parameter is at least one of a length of the charging period calculated based on the voltage value and a length of the discharging period calculated based on the voltage value. [Configuration 9] The detection device according to configuration 8, wherein the determination unit determines whether a capacitance increase fault or a capacitance decrease fault has occurred in the power storage unit based on the acquired determination parameter. [Configuration 10] The detection device according to any one of configurations 7 to 9, wherein the judgment parameter is a difference between the voltage values ​​of two different power storage units during at least one of the charging period and a period during which the voltage value during the charging period is maintained. [Configuration 11] 11. The detection device according to any one of configurations 7 to 10, wherein the determination parameter is the voltage value in at least one of the charging period and a period during which the voltage value is maintained in the charging period. [Configuration 12] 12. The detection device according to any one of configurations 2 to 6 and 11, wherein the determination unit identifies which of the power storage units has a malfunction based on the acquired determination parameter. [Configuration 13] The judgment parameter is a first determination parameter being either the length of the charging period calculated based on the voltage value or the length of the discharging period calculated based on the voltage value; a second judgment parameter that is the voltage value of each of the power storage units during a period in which the first judgment parameter is calculated; and and The determination unit is determining whether at least one of the power storage units has a capacitance increase failure or a capacitance decrease failure based on the acquired first judgment parameter; The detection device according to configuration 7, further comprising: determining which of the power storage units has experienced a determined capacitance increase fault or capacitance decrease fault based on the acquired second determination parameter. [Configuration 14] a plurality of power storage units (21, 22) connected in series; a detection method for detecting a fault in at least one of the power storage units, the detection method being applied to an inverter (30) including switches (Su1-Su4, Sv1-Sv4, Sw1-Sw4) electrically connected to the power storage units and armature windings (11U, 11V, 11W) of a rotating electric machine (10), the detection method comprising: the inverter is a multilevel inverter that performs switching control of the switch so as to apply to the armature winding either an output voltage of a plurality of voltage levels that can be output from the series-connected array of the power storage units or zero voltage, based on a voltage value of at least one of the power storage units; an acquisition step of acquiring a determination parameter, which is at least one of a calculation result based on the voltage value and the voltage value; a determination step of determining whether or not the failure has occurred based on the acquired determination parameters; The detection method comprises: [Explanation of symbols]

[0146] 10... rotating electric machine, 11U, 11V, 11W... U-, V-, and W-phase windings, 21, 22... first and second capacitors, 30... inverter, 50... control device, Su1 to Su4, Sv1 to Sv4, Sw1 to Sw4... U-, V-, and W-phase first to fourth switches.

Claims

1. a first storage unit (21) and a second storage unit (22) connected in series; a first switch (Su1, Sv1, Sw1), a second switch (Su2, Sv2, Sw2), a third switch (Su3, Sv3, Sw3), and a fourth switch (Su4, Sv4, Sw4) connected in series; first clamp diodes (Dc1, Dc3, Dc5), and second clamp diodes (Dc2, Dc4, Dc6); A detection device (50) is applied to a multi-phase inverter (30) including the above-mentioned and detects a fault in at least one of the power storage units, In each phase, a high potential side terminal of the first switch is connected to a first end of the first power storage unit, a second end of the first power storage unit and a first end of the second power storage unit are connected via a neutral point; In each phase, a low potential side terminal of the fourth switch is connected to a second end of the second power storage unit, In each phase, a low potential side terminal of the second switch and a high potential side terminal of the third switch are connected to an armature winding (11U, 11V, 11W) of a rotating electric machine (10), In each phase, a low potential side terminal of the first switch and a high potential side terminal of the second switch are connected to the cathode of the first clamp diode, In each phase, the anode of the first clamp diode is connected to the cathode of the second clamp diode; In each phase, the anode of the second clamp diode is connected to the low potential side terminal of the third switch and the high potential side terminal of the fourth switch, In each phase, a connection point of the first clamp diode and the second clamp diode is connected to the neutral point, The inverter is an output voltage of level H that is output by turning on the first switch and the second switch and turning off the third switch and the fourth switch; an output voltage of level M that is output by turning on the second switch and the third switch and turning off the first switch and the fourth switch; an output voltage of level L that is output by turning on the third switch and the fourth switch and turning off the first switch and the second switch; A zero voltage at which an output voltage of level H, an output voltage of level M, or an output voltage of level L is output in each phase; a three-level inverter that performs switching control of the first switch, the second switch, the third switch, and the fourth switch based on a voltage value of at least one of the power storage units so as to apply any one of the output voltages from an acquisition unit that acquires, as a determination parameter, an amount of change over time in the voltage value when an output voltage of level H, an output voltage of level L, or zero voltage is output during the switching control; a determination unit that determines whether or not the failure has occurred based on the acquired determination parameters; A detection device comprising:

2. a first storage unit (21) and a second storage unit (22) connected in series; a first switch (Su1, Sv1, Sw1), a second switch (Su2, Sv2, Sw2), a third switch (Su3, Sv3, Sw3), and a fourth switch (Su4, Sv4, Sw4) connected in series; first clamp diodes (Dc1, Dc3, Dc5), and second clamp diodes (Dc2, Dc4, Dc6); A detection device (50) is applied to an inverter (30) including the above and detects a fault in at least one of the power storage units, a high potential side terminal of the first switch connected to a first end of the first power storage unit; a second end of the first power storage unit and a first end of the second power storage unit are connected via a neutral point; a low potential side terminal of the fourth switch is connected to a second end of the second power storage unit; A low potential side terminal of the second switch and a high potential side terminal of the third switch are connected to armature windings (11U, 11V, 11W) of a rotating electric machine (10), a low potential side terminal of the first switch and a high potential side terminal of the second switch are connected to the cathode of the first clamp diode; the anode of the first clamp diode is connected to the cathode of the second clamp diode; an anode of the second clamp diode is connected to a low potential side terminal of the third switch and a high potential side terminal of the fourth switch; a connection point of the first clamp diode and the second clamp diode is connected to the neutral point, The inverter is an output voltage of level H that is output by turning on the first switch and the second switch and turning off the third switch and the fourth switch; an output voltage of level M that is output by turning on the second switch and the third switch and turning off the first switch and the fourth switch; an output voltage of level L that is output by turning on the third switch and the fourth switch and turning off the first switch and the second switch; a three-level inverter that performs switching control of the first switch, the second switch, the third switch, and the fourth switch based on a voltage value of at least one of the power storage units so as to apply any one of the output voltages from an acquisition unit that acquires, as a determination parameter, an amount of change over time in the voltage value when an output voltage of level M is output during the switching control; a determination unit that determines whether or not the failure has occurred based on the acquired determination parameters; A detection device comprising:

3. a power supply (20) that supplies driving power to the rotating electric machine is connected to the series-connected body of each of the power storage units; a power switch (40) is provided between the power source and the series-connected body of each of the power storage units; the acquisition unit acquires, in addition to the determination parameter, at least one of a length of a charging period from when the power switch is turned on until the voltage value reaches a predetermined charging value, and a length of a discharging period from when the power switch is turned off until the voltage value becomes equal to or lower than a predetermined discharging value; 3. The detection device according to claim 1, wherein the determination unit determines whether or not the failure has occurred based on at least one of the acquired length of the charging period and the acquired length of the discharging period in addition to the acquired determination parameter.

4. The detection device according to claim 3 , wherein the determination unit determines whether a capacitance increase failure or a capacitance decrease failure has occurred in the power storage unit based on the acquired determination parameter.

5. A power supply (20) that supplies driving power to the rotating electric machine is connected to the series-connected body of each of the power storage units, a power switch (40) is provided between the power source and the series-connected body of each of the power storage units; the acquisition unit acquires, in addition to the determination parameter, a difference between the voltage values ​​of the two different power storage units during at least one of a charging period from when the power switch is turned on until the voltage value reaches a predetermined charging value and a period during which the voltage value is maintained during the charging period; The detection device according to claim 1 , wherein the determination unit determines whether or not the failure has occurred based on the obtained difference in addition to the obtained determination parameter.

6. A power supply (20) that supplies driving power to the rotating electric machine is connected to the series-connected body of each of the power storage units, a power switch (40) is provided between the power source and the series-connected body of each of the power storage units; the acquisition unit acquires, in addition to the determination parameter, the voltage value during at least one of a charging period from when the power switch is turned on until the voltage value reaches a predetermined charging value and a period during which the voltage value is maintained during the charging period; The detection device according to claim 1 , wherein the determination unit determines whether or not the failure has occurred based on the acquired voltage value in addition to the acquired determination parameter.

7. The detection device according to claim 1 , wherein the determination unit identifies which of the power storage units has a failure based on the acquired determination parameter.

8. a plurality of power storage units (21, 22) connected in series; switches (Su1 to Su4, Sv1 to Sv4, Sw1 to Sw4) electrically connected to the respective power storage units and the armature windings (11U, 11V, 11W) of the rotating electric machine (10); A detection device (50) is applied to an inverter (30) including the above and detects a fault in at least one of the power storage units, the inverter is a multilevel inverter that performs switching control of the switch so that either zero voltage or any output voltage of a plurality of voltage levels that can be output from the series-connected array of the power storage units is applied to the armature winding, based on a voltage value of at least one of the power storage units; a power supply (20) that supplies driving power to the rotating electric machine is connected to the series-connected body of each of the power storage units; a power switch (40) is provided between the power source and the series-connected body of each of the power storage units; an acquisition unit that acquires a first judgment parameter and a second judgment parameter; a determination unit that determines whether or not the failure has occurred based on the acquired first determination parameter and the acquired second determination parameter; Equipped with The acquisition unit acquiring, as the first determination parameter, at least one of a length of a charging period from when the power switch is turned on until the voltage value reaches a predetermined charging value and a length of a discharging period from when the power switch is turned off until the voltage value becomes equal to or lower than a predetermined discharging value; The voltage value of each of the power storage units during the period in which the first determination parameter is calculated is acquired as the second determination parameter; The determination unit determining whether a capacitance increase failure or a capacitance decrease failure has occurred in at least one of the power storage units based on the acquired first determination parameter; The detection device identifies which of the power storage units has the determined capacitance increase fault or capacitance decrease fault based on the acquired second determination parameter.

9. a first storage unit (21) and a second storage unit (22) connected in series; a first switch (Su1, Sv1, Sw1), a second switch (Su2, Sv2, Sw2), a third switch (Su3, Sv3, Sw3), and a fourth switch (Su4, Sv4, Sw4) connected in series; first clamp diodes (Dc1, Dc3, Dc5), and second clamp diodes (Dc2, Dc4, Dc6); A program for causing a computer to execute a process for detecting a fault in at least one of the power storage units, the program being applied to a multi-phase inverter including the inverter, In each phase, a high potential side terminal of the first switch is connected to a first end of the first power storage unit, a second end of the first power storage unit and a first end of the second power storage unit are connected via a neutral point; In each phase, a low potential side terminal of the fourth switch is connected to a second end of the second power storage unit, In each phase, a low potential side terminal of the second switch and a high potential side terminal of the third switch are connected to an armature winding (11U, 11V, 11W) of a rotating electric machine (10), In each phase, a low potential side terminal of the first switch and a high potential side terminal of the second switch are connected to the cathode of the first clamp diode, In each phase, the anode of the first clamp diode is connected to the cathode of the second clamp diode; In each phase, the anode of the second clamp diode is connected to the low potential side terminal of the third switch and the high potential side terminal of the fourth switch, In each phase, a connection point of the first clamp diode and the second clamp diode is connected to the neutral point, The inverter is an output voltage of level H that is output by turning on the first switch and the second switch and turning off the third switch and the fourth switch; an output voltage of level M that is output by turning on the second switch and the third switch and turning off the first switch and the fourth switch; an output voltage of level L that is output by turning on the third switch and the fourth switch and turning off the first switch and the second switch; A zero voltage at which an output voltage of level H, an output voltage of level M, or an output voltage of level L is output in each phase; a three-level inverter that performs switching control of the first switch, the second switch, the third switch, and the fourth switch based on a voltage value of at least one of the power storage units so as to apply any one of the output voltages from an acquisition process of acquiring, as a determination parameter, an amount of change over time in the voltage value when an output voltage of level H, an output voltage of level L, or zero voltage is output during the switching control; a determination process for determining whether or not the failure has occurred based on the acquired determination parameters; A program that causes the computer to execute the above.

10. A first storage unit (21) and a second storage unit (22) connected in series, a first switch (Su1, Sv1, Sw1), a second switch (Su2, Sv2, Sw2), a third switch (Su3, Sv3, Sw3), and a fourth switch (Su4, Sv4, Sw4) connected in series; first clamp diodes (Dc1, Dc3, Dc5), and second clamp diodes (Dc2, Dc4, Dc6); and a program for causing a computer to execute a process for detecting a fault in at least one of the power storage units, the program being applied to an inverter including the inverter and comprising: a high potential side terminal of the first switch connected to a first end of the first power storage unit; a second end of the first power storage unit and a first end of the second power storage unit are connected via a neutral point; a low potential side terminal of the fourth switch is connected to a second end of the second power storage unit; A low potential side terminal of the second switch and a high potential side terminal of the third switch are connected to armature windings (11U, 11V, 11W) of a rotating electric machine (10), a low potential side terminal of the first switch and a high potential side terminal of the second switch are connected to the cathode of the first clamp diode; the anode of the first clamp diode is connected to the cathode of the second clamp diode; an anode of the second clamp diode is connected to a low potential side terminal of the third switch and a high potential side terminal of the fourth switch; a connection point of the first clamp diode and the second clamp diode is connected to the neutral point, The inverter is an output voltage of level H that is output by turning on the first switch and the second switch and turning off the third switch and the fourth switch; an output voltage of level M that is output by turning on the second switch and the third switch and turning off the first switch and the fourth switch; an output voltage of level L that is output by turning on the third switch and the fourth switch and turning off the first switch and the second switch; a three-level inverter that performs switching control of the first switch, the second switch, the third switch, and the fourth switch based on a voltage value of at least one of the power storage units so as to apply any one of the output voltages from an acquisition process for acquiring, as a determination parameter, an amount of change over time in the voltage value when an output voltage of level M is output during the switching control; a determination process for determining whether or not the failure has occurred based on the acquired determination parameters; A program that causes the computer to execute the above.

11. A plurality of power storage units (21, 22) connected in series; switches (Su1 to Su4, Sv1 to Sv4, Sw1 to Sw4) electrically connected to the respective power storage units and the armature windings (11U, 11V, 11W) of the rotating electric machine (10); and a program for causing a computer to execute a process for detecting a fault in at least one of the power storage units, the program being applied to an inverter including the inverter and comprising: the inverter is a multilevel inverter that performs switching control of the switch so that either zero voltage or any output voltage of a plurality of voltage levels that can be output from the series-connected array of the power storage units is applied to the armature winding, based on a voltage value of at least one of the power storage units; a power supply (20) that supplies driving power to the rotating electric machine is connected to the series-connected body of each of the power storage units; a power switch (40) is provided between the power source and the series-connected body of each of the power storage units; an acquisition process for acquiring a first judgment parameter and a second judgment parameter; a determination process for determining whether or not the failure has occurred based on the acquired first determination parameter and the acquired second determination parameter; causing the computer to execute In the acquisition process, acquiring, as the first determination parameter, at least one of a length of a charging period from when the power switch is turned on until the voltage value reaches a predetermined charging value and a length of a discharging period from when the power switch is turned off until the voltage value becomes equal to or lower than a predetermined discharging value; The voltage value of each of the power storage units during the period in which the first determination parameter is calculated is acquired as the second determination parameter; In the determination process, determining whether a capacitance increase failure or a capacitance decrease failure has occurred in at least one of the power storage units based on the acquired first determination parameter; and a program that identifies, based on the acquired second determination parameter, in which of the power storage units the determined capacitance increase failure or capacitance decrease failure has occurred.

12. A first storage unit (21) and a second storage unit (22) connected in series, a first switch (Su1, Sv1, Sw1), a second switch (Su2, Sv2, Sw2), a third switch (Su3, Sv3, Sw3), and a fourth switch (Su4, Sv4, Sw4) connected in series; first clamp diodes (Dc1, Dc3, Dc5), and second clamp diodes (Dc2, Dc4, Dc6); a detection method for detecting a fault in at least one of the power storage units, the method being applied to a multi-phase inverter including the inverter, the method causing a computer to execute a process for detecting a fault in at least one of the power storage units, In each phase, a high potential side terminal of the first switch is connected to a first end of the first power storage unit, a second end of the first power storage unit and a first end of the second power storage unit are connected via a neutral point; In each phase, a low potential side terminal of the fourth switch is connected to a second end of the second power storage unit, In each phase, a low potential side terminal of the second switch and a high potential side terminal of the third switch are connected to an armature winding (11U, 11V, 11W) of a rotating electric machine (10), In each phase, a low potential side terminal of the first switch and a high potential side terminal of the second switch are connected to the cathode of the first clamp diode, In each phase, the anode of the first clamp diode is connected to the cathode of the second clamp diode; In each phase, the anode of the second clamp diode is connected to the low potential side terminal of the third switch and the high potential side terminal of the fourth switch, In each phase, a connection point of the first clamp diode and the second clamp diode is connected to the neutral point, The inverter is an output voltage of level H that is output by turning on the first switch and the second switch and turning off the third switch and the fourth switch; an output voltage of level M that is output by turning on the second switch and the third switch and turning off the first switch and the fourth switch; an output voltage of level L that is output by turning on the third switch and the fourth switch and turning off the first switch and the second switch; A zero voltage at which an output voltage of level H, an output voltage of level M, or an output voltage of level L is output in each phase; a three-level inverter that performs switching control of the first switch, the second switch, the third switch, and the fourth switch based on a voltage value of at least one of the power storage units so as to apply any one of the output voltages from an acquisition process of acquiring, as a determination parameter, an amount of change over time in the voltage value when an output voltage of level H, an output voltage of level L, or zero voltage is output during the switching control; a determination process for determining whether or not the failure has occurred based on the acquired determination parameters; The detection method includes causing the computer to execute the above steps.

13. A first storage unit (21) and a second storage unit (22) connected in series, a first switch (Su1, Sv1, Sw1), a second switch (Su2, Sv2, Sw2), a third switch (Su3, Sv3, Sw3), and a fourth switch (Su4, Sv4, Sw4) connected in series; first clamp diodes (Dc1, Dc3, Dc5), and second clamp diodes (Dc2, Dc4, Dc6); and a detection method for causing a computer to execute a process for detecting a fault in at least one of the power storage units, the detection method being applied to an inverter including the inverter (30), a high potential side terminal of the first switch connected to a first end of the first power storage unit; a second end of the first power storage unit and a first end of the second power storage unit are connected via a neutral point; a low potential side terminal of the fourth switch is connected to a second end of the second power storage unit; A low potential side terminal of the second switch and a high potential side terminal of the third switch are connected to armature windings (11U, 11V, 11W) of a rotating electric machine (10), a low potential side terminal of the first switch and a high potential side terminal of the second switch are connected to the cathode of the first clamp diode; the anode of the first clamp diode is connected to the cathode of the second clamp diode; an anode of the second clamp diode is connected to a low potential side terminal of the third switch and a high potential side terminal of the fourth switch; a connection point of the first clamp diode and the second clamp diode is connected to the neutral point, The inverter is an output voltage of level H that is output by turning on the first switch and the second switch and turning off the third switch and the fourth switch; an output voltage of level M that is output by turning on the second switch and the third switch and turning off the first switch and the fourth switch; an output voltage of level L that is output by turning on the third switch and the fourth switch and turning off the first switch and the second switch; a three-level inverter that performs switching control of the first switch, the second switch, the third switch, and the fourth switch based on a voltage value of at least one of the power storage units so as to apply any one of the output voltages from an acquisition process for acquiring, as a determination parameter, an amount of change over time in the voltage value when an output voltage of level M is output during the switching control; a determination process for determining whether or not the failure has occurred based on the acquired determination parameters; The detection method includes causing the computer to execute the above steps.

14. A plurality of series-connected power storage units (21, 22), switches (Su1 to Su4, Sv1 to Sv4, Sw1 to Sw4) electrically connected to the respective power storage units and the armature windings (11U, 11V, 11W) of the rotating electric machine (10); and a detection method for causing a computer to execute a process for detecting a fault in at least one of the power storage units, the detection method being applied to an inverter including the inverter (30), the inverter is a multilevel inverter that performs switching control of the switch so that either zero voltage or any output voltage of a plurality of voltage levels that can be output from the series-connected array of the power storage units is applied to the armature winding, based on a voltage value of at least one of the power storage units; A power source (20) that supplies driving power to the rotating electric machine is connected to the series-connected body of each of the power storage units, a power switch (40) is provided between the power source and the series-connected body of each of the power storage units; an acquisition process for acquiring a first judgment parameter and a second judgment parameter; a determination process for determining whether or not the failure has occurred based on the acquired first determination parameter and the acquired second determination parameter; causing the computer to execute In the acquisition process, acquiring, as the first determination parameter, at least one of a length of a charging period from when the power switch is turned on until the voltage value reaches a predetermined charging value and a length of a discharging period from when the power switch is turned off until the voltage value becomes equal to or lower than a predetermined discharging value; acquiring, as the second determination parameter, the voltage value of each of the power storage units during a period in which the first determination parameter is calculated; In the determination process, determining whether a capacitance increase failure or a capacitance decrease failure has occurred in at least one of the power storage units based on the acquired first determination parameter; a detection method for identifying which of the power storage units has experienced the determined capacitance increase fault or capacitance decrease fault, based on the acquired second determination parameter;

Images