Control device, program, and control method

Abstract

A control device (50) is applied to a system comprising: a first electricity storage unit (11) and a second electricity storage unit (12); an inverter (10) having multi-phase upper-arm switches (SWH) and lower-arm switches (SWL); and a smoothing capacitor (13). The system also comprises an inter-electricity-storage-unit switch (SMR3), a motor-side switch (20), main switches (SMR1, SMR2), and a bypass switch (30). The control device comprises: a switch control unit that controls the upper- and lower-arm switches, the inter-electricity-storage-unit switch, the motor-side switch, the main switches, and the bypass switch; and a determination unit that determines whether an open failure has occurred in the main switch or the inter-electricity-storage-unit switch. When it is determined that the open failure has occurred in the main switch or the inter-electricity-storage-unit switch, the switch control unit outputs an ON command to the motor-side switch.

Description

Control Device, Program, and Control Method Cross - Reference to Related Applications

[0001] This application is based on Japanese Application No. 2025 - 016971 filed on February 4, 2025, the contents of which are incorporated herein by reference.

[0002] This disclosure relates to a control device, a program, and a control method.

[0003] Conventionally, as described in, for example, Patent Document 1, a system including a first and a second power storage unit, an inverter, and a motor is known. The system includes an inter - power - storage - unit switch, a motor - side switch, a main switch, and a bypass switch to switch the first and the second power storage units between a series - connected state and a parallel - connected state. This system can switch the voltage in the system by switching the control states of the inter - power - storage - unit switch, the motor - side switch, and the bypass switch to switch the connection state of the first and the second power storage units.

[0004] International Publication No. 2024 / 024425

[0005] When the first and the second power storage units are in a series - connected state and the inverter is under switching control, the main switch and the inter - power - storage - unit switch forming the path in the series - connected state may experience an open failure. In this case, the power supply from the first and the second power storage units to the motor is interrupted, and an overvoltage occurs in the system. It is necessary to provide a smoothing capacitor with a withstand voltage considering the occurrence of overvoltage in such a series - connected state. In this case, there is a concern that the physical size of the smoothing capacitor becomes large and the system becomes large - sized.

[0006] This disclosure has been made to solve the above problems, and its main object is to reduce the overvoltage that occurs when an open failure occurs in the main switch or the inter - power - storage - unit switch.

[0007] This disclosure relates to a control device applicable to a system comprising: a first energy storage unit and a second energy storage unit; an inverter having multiple-phase upper arm switches and lower arm switches; a high-potential path connecting the high-potential side terminal of the upper arm switch to the positive terminal of the first energy storage unit; a low-potential path connecting the low-potential side terminal of the lower arm switch to the negative terminal of the second energy storage unit; a smoothing capacitor connected in parallel to the series connection of the upper arm switch and the lower arm switch; and a motor having an armature winding connected to the low-potential side terminal of the upper arm switch and the high-potential side terminal of the lower arm switch, wherein the system comprises: an inter-energy storage unit switch provided in the inter-energy storage unit electrical path connecting the negative terminal of the first energy storage unit and the positive terminal of the second energy storage unit; a motor-side switch provided in the motor electrical path connecting the armature winding and the inter-energy storage unit electrical path; and a main switch provided in at least one of the high-potential path and the low-potential path. The control device comprises a bypass switch that makes an electrical connection between at least one of the following: an electrical connection between the positive terminals of the first and second energy storage units, and an electrical connection between the negative terminals of the first and second energy storage units, and the control device comprises a switch control unit that controls the upper and lower arm switches, the energy storage unit switch, the motor side switch, the main switch, and the bypass switch, and a determination unit that determines whether an open fault has occurred in the main switch or the energy storage unit switch when the switch control unit outputs an ON command to the main switch and the energy storage unit switch, and the switch control unit outputs an ON command to the motor side switch when it is determined that the main switch or the energy storage unit switch has an open fault.

[0008] When the inverter is switching-controlled with the first and second energy storage units connected in series, if the main switch or the switch between the energy storage units fails open, the closed circuit of the first energy storage unit, the second energy storage unit, the high-potential path, the inverter, the armature winding, and the low-potential path is interrupted. As a result, the power supply from the first and second energy storage units to the motor is cut off, and an overvoltage occurs in the system. In this case, the determination unit determines that the main switch or the switch between the energy storage units has failed open. Subsequently, the switch control unit outputs an ON command to the motor-side switch. This quickly secures a closed circuit including the first or second energy storage unit, the inverter, and the motor, and reduces the overvoltage in the system. As a result, the rise in voltage across the smoothing capacitor is reduced. Therefore, the system can employ smoothing capacitors with low voltage ratings and small size. As a result, the system can be miniaturized.

[0009] The above-mentioned and other purposes, features and advantages of this disclosure will become clearer from the following detailed description with reference to the attached drawings. The drawings are as follows: Figure 1 is an overall configuration diagram of the system according to the first embodiment; Figure 2 is a flowchart showing the procedure for overvoltage reduction processing; Figure 3 is a diagram showing an example of overvoltage reduction processing; Figure 4 is a diagram showing an example of overvoltage reduction processing; Figure 5 is a diagram showing an example of overvoltage reduction processing; Figure 6 is a diagram showing an example of overvoltage reduction processing; Figure 7 is an overall configuration diagram of the system according to a modification of the first embodiment; Figure 8 is an overall configuration diagram of the system according to the second embodiment; Figure 9 is a flowchart showing the procedure for overvoltage reduction processing according to the third embodiment; Figure 10 is a configuration diagram of the control device according to the fourth embodiment; Figure 11 is a flowchart showing the procedure for overvoltage reduction processing according to the fourth embodiment; Figure 12 is a diagram showing a part of the system according to the fifth embodiment; Figure 13 is a diagram showing a part of the system according to a modification of the fifth embodiment; and Figure 14 is a flowchart showing the procedure for overvoltage reduction processing according to the sixth embodiment.

[0010] Multiple embodiments will be described with reference to the drawings. In multiple embodiments, functionally and / or structurally corresponding and / or related parts may be given the same reference numeral, or reference numerals that differ by hundreds or more digits. For corresponding and / or related parts, refer to the descriptions of other embodiments.

[0011] <First Embodiment> Hereinafter, a first embodiment of the system relating to this disclosure will be described with reference to the drawings. In this embodiment, the system is installed in a vehicle such as an electric vehicle or a hybrid vehicle.

[0012] As shown in Figure 1, the system comprises a first battery 11 (corresponding to the "first energy storage unit"), a second battery 12 (corresponding to the "second energy storage unit"), an inverter 10, a motor 41, a high-potential path 21, and a low-potential path 22. The high-potential path 21 is connected to the positive terminal of the first battery 11 and the inverter 10. The low-potential path 22 is connected to the negative terminal of the second battery 12 and the inverter 10. The first and second batteries 11 and 12 are secondary batteries such as lithium batteries or nickel-metal hydride batteries. The rated voltages (e.g., 400V) of the first and second batteries 11 and 12 may be the same or different.

[0013] In this embodiment, the inverter 10 is equipped with three series connections of upper and lower arm switches SWH and SWL for three phases (U phase, W phase, and V phase). The high-potential terminal of the upper arm switch SWH is connected to the high-potential path 21. The low-potential terminal of the lower arm switch SWL is connected to the low-potential path 22. In this embodiment, the upper and lower arm switches SWH and SWL are semiconductor switching elements, specifically IGBTs. In the upper and lower arm switches SWH and SWL, the high-potential terminal is the collector and the low-potential terminal is the emitter. Upper and lower arm diodes DH and DL, which are freewheeling diodes, are connected in antiparallel to the upper and lower arm switches SWH and SWL.

[0014] The motor 41 is a three-phase synchronous machine and comprises star-connected armature windings 42 for phases U, W, and V, and a rotor (not shown). The armature windings 42 for each phase are offset by 120° in electrical angle and connected at a neutral point O. The armature windings 42 for each phase are connected to the low-potential terminal of the upper arm switch SWH and the high-potential terminal of the lower arm switch SWL for each phase. The motor 41 is, for example, a permanent magnet synchronous machine. The rotor is capable of transmitting power to the vehicle's drive wheels. Therefore, the motor 41 is the source of torque that drives the vehicle.

[0015] The system comprises a smoothing capacitor 13 and a series connection of a discharge resistor 14 and a discharge switch 40. The first end of the smoothing capacitor 13 is connected to the high-potential terminal of the upper arm switch SWH, and the second end of the smoothing capacitor 13 is connected to the low-potential terminal of the lower arm switch SWL. The first end of the discharge resistor 14 is connected to the first end of the smoothing capacitor 13. In this embodiment, the discharge switch 40 is a semiconductor switching element, specifically an IGBT. The second end of the discharge resistor 14 is connected to the collector, which is the high-potential terminal of the discharge switch 40. The second end of the smoothing capacitor 13 is connected to the emitter, which is the low-potential terminal of the discharge switch 40. A freewheeling diode D is connected in antiparallel to the discharge switch 40.

[0016] The system includes a first main switch SMR1 and a second main switch SMR2. Specifically, the first main switch SMR1 is located in the high-potential path 21. The first end of the first main switch SMR1 is connected to the positive terminal of the first battery 11, and the second end of the first main switch SMR1 is connected to the high-potential side terminal of the upper arm switch SWH. The second main switch SMR2 ​​is located in the low-potential path 22. The first end of the second main switch SMR2 ​​is connected to the negative terminal of the second battery 12, and the second end of the second main switch SMR2 ​​is connected to the low-potential side terminal of the lower arm switch SWL. As a result, the first and second main switches SMR1 and SMR2 ​​can electrically connect or disconnect the first and second batteries 11 and 12 from the inverter 10. In this embodiment, the first main switch SMR1 and the second main switch SMR2 ​​are mechanical relays. Furthermore, the first and second main switches SMR1 and SMR2 ​​are not limited to mechanical relays, but may also be semiconductor switching elements, for example.

[0017] The system includes a third main switch SMR3 (corresponding to the "inter-storage unit switch"), a motor-side switch 20, and a bypass switch 30. Each of the switches SMR3, 20, and 30 is used to switch the first storage battery 11 and the second storage battery 12 to either a series connection state or a parallel connection state, as described later.

[0018] The third main switch SMR3 is provided in the battery-to-battery path 23 (corresponding to the "electrical path between energy storage units") that connects the negative terminal of the first battery 11 and the positive terminal of the second battery 12. In this embodiment, the third main switch SMR3 is a mechanical relay. However, the third main switch SMR3 is not limited to a mechanical relay; for example, it may be a semiconductor switching element.

[0019] The bypass switch 30 connects the negative terminal of the first battery 11 and the negative terminal of the second battery 12. In this embodiment, the bypass switch 30 is a mechanical relay. However, the bypass switch 30 is not limited to a mechanical relay; for example, it may be a semiconductor switching element.

[0020] The motor-side switch 20 is located in the motor electrical path 24, which connects the second battery 12 side and the neutral point O to the third main switch SMR3 in the battery-to-battery path 23. The motor-side switch 20 consists of a first motor-side switch 20A and a second motor-side switch 20B. In this embodiment, semiconductor switching elements are used as the first motor-side switch 20A and the second motor-side switch 20B, specifically IGBTs are used. First and second arm diodes DA and DB, which are freewheeling diodes, are connected in antiparallel to the first and second motor-side switches 20A and 20B.

[0021] Specifically, the first motor-side switch 20A has its collector facing the positive terminal of the second battery 12, and the first motor-side switch 20A has its emitter facing the emitter of the second motor-side switch 20B. The second motor-side switch 20B has its collector facing the neutral point O.

[0022] The first and second batteries 11 and 12 can be charged by an external charger installed outside the vehicle. The external charger is, for example, a stationary charger. In the high-potential path 21, a positive electrode connection (not shown) is provided on the upper arm switch SWH side of the first main switch SMR1. The positive electrode connection can be connected to the positive terminal of the external charger. In the low-potential path 22, a negative electrode connection (not shown) is provided on the lower arm switch SWL side of the second main switch SMR2. The negative electrode connection can be connected to the negative terminal of the external charger.

[0023] The system includes a first voltage sensor 61, a second voltage sensor 62, and a third voltage sensor 63. The first voltage sensor 61 detects a voltage detection value VA, which is the terminal voltage of the first main switch SMR1. The second voltage sensor 62 detects a voltage detection value VB, which is the terminal voltage of the second main switch SMR2. The third voltage sensor 63 detects a voltage detection value VC, which is the terminal voltage of the third main switch SMR3. The detection values ​​of each voltage sensor 61, 62, and 63 are input to a control device 50 included in the system.

[0024] The system is equipped with a current sensor 64. The current sensor 64 detects the current detection value IA, which is the current flowing through the first battery 11. In the example shown in Figure 1, the current sensor 64 is located on the side of the high-potential path 21 closer to the first battery 11 than the first main switch SMR1. The detection value of the current sensor 64 is input to the control device 50.

[0025] The system is equipped with a rotation angle sensor 65. The rotation angle sensor 65 detects the rotation angle (electrical angle) of the rotor. The rotation angle sensor 65 is, for example, a resolver. The value detected by the rotation angle sensor 65 is input to the control device 50.

[0026] The system includes a first temperature sensor 66, a second temperature sensor 67, and a third temperature sensor 68. The first temperature sensor 66 detects a temperature value TA, which is the temperature of the first main switch SMR1. The second temperature sensor 67 detects a temperature value TB, which is the temperature of the second main switch SMR2. The third temperature sensor 68 detects a temperature value TC, which is the temperature of the third main switch SMR3. The detected values ​​from each of the temperature sensors 66, 67, and 68 are input to the control device 50.

[0027] The control device 50 is an electronic control unit (ECU) that performs various controls on the system, and comprises a processor 51 as hardware, a storage unit 52, and a communication bus 53 that connects the processor 51 and the storage unit 52.

[0028] The memory unit 52 includes memory and storage as hardware. The memory is a storage device for storing data used in processing by the control device 50. The memory provides the processor 51 with a temporary workspace for use when the processor 51 performs processing. The memory includes, for example, ROM or RAM. The storage is a storage device that stores various programs and data for the processor 51 to read and execute, and is a non-transitory tangible storage medium. The storage includes, for example, an HDD or flash memory. The storage stores program information and the like for processing described later.

[0029] For example, program information stored on a non-transitional physical recording medium is installed in the storage unit 52. The recording medium is, for example, a USB memory stick, CD-ROM, or DVD. Also, for example, program information transmitted via a communication network, such as OTA (Over The Air), is installed in the storage unit 52.

[0030] The first and second batteries 11 and 12 are charged by an external charger, which is either a high-voltage charger or a low-voltage charger. In this embodiment, the charging voltage of the high-voltage charger is approximately the same as the terminal voltage of the series connection of the first and second batteries 11 and 12, for example, 800V. The charging voltage of the low-voltage charger is lower than the terminal voltage of the series connection of the first and second batteries 11 and 12, for example, 400V.

[0031] When the first and second batteries 11 and 12 are being charged by the high-voltage charger, the control device 50 outputs ON commands to the first, second, and third main switches SMR1, SMR2, and SMR3. The control device 50 also outputs OFF commands to the bypass switch 30 and the motor-side switch 20. As a result, the first and second batteries 11 and 12 are connected in series with respect to the high-voltage charger (hereinafter referred to as the series connection state). The control device 50 also outputs OFF commands to the upper and lower arm switches SWH and SWL. As a result, the first and second batteries 11 and 12 are charged in the series connection state.

[0032] When the first and second batteries 11 and 12 are being charged by the low-voltage charger, the control device 50 outputs ON commands to the first and second main switches SMR1 and SMR2, the motor-side switch 20, the bypass switch 30, and at least one-phase upper arm switch SWH. The control device 50 also outputs OFF commands to the third main switch SMR3 and the lower arm switch SWL. As a result, the first and second batteries 11 and 12 are charged in a state where they are connected in parallel to the low-voltage charger (hereinafter referred to as the parallel connection state). In this embodiment, the control device 50 corresponds to the "switch control unit".

[0033] The control device 50 controls the switching of the upper and lower arm switches SWH and SWL that constitute the inverter 10 in order to feed back the control amount of the motor 41 to a command value based on the detected values ​​of each sensor. The control amount is, for example, torque. In each phase, the control device 50 alternately outputs ON commands to the upper arm switch SWH and the lower arm switch SWL. Through this feedback control, the rotational power of the rotor is transmitted to the drive wheels, and the vehicle moves.

[0034] Next, the overvoltage reduction process, which is a characteristic configuration of this embodiment, will be explained using Figure 2. This process is designed to prepare for the case where the first, second, and third main switches SMR1, SMR2, and SMR3 have an open fault while the vehicle is running in a series connection state (specifically, while the inverter 10 is controlling the switching of the upper and lower arm switches SWH and SWL).

[0035] In step S10, the control device 50 determines whether or not any of the first, second, or third main switches SMR1, SMR2, or SMR3 is experiencing an open fault. An example of a method for determining whether or not an open fault is occurring is described below.

[0036] When the control device 50 outputs an ON command to the first main switch SMR1, it determines whether the first main switch SMR1 is experiencing an open fault based on the detection value of the first voltage sensor 61 input to the control device 50. For example, if the control device 50 determines that the input voltage detection value VA of the first main switch SMR1 (specifically, the absolute value of the voltage detection value VA) is higher than the voltage threshold Vjd, it determines that the first main switch SMR1 is experiencing an open fault. On the other hand, if the control device 50 determines that the input voltage detection value VA of the first main switch SMR1 is less than or equal to the voltage threshold Vjd, it determines that the first main switch SMR1 is not experiencing an open fault.

[0037] In step S10, the control device 50 determines whether the second main switch SMR2 ​​is experiencing an open fault. One example of a method for determining whether the second main switch SMR2 ​​is experiencing an open fault is to replace the first main switch SMR1 in step S10 with the second main switch SMR2, replace the first voltage sensor 61 in step S10 with the second voltage sensor 62, and replace the voltage detection value VA detected by the first voltage sensor 61 with the voltage detection value VB detected by the second voltage sensor 62.

[0038] In step S10, the control device 50 determines whether the third main switch SMR3 is experiencing an open fault. One example of a method for determining whether the third main switch SMR3 is experiencing an open fault is to replace the first main switch SMR1 in step S10 with the third main switch SMR3, replace the first voltage sensor 61 in step S10 with the third voltage sensor 63, and replace the voltage detection value VA detected by the first voltage sensor 61 with the voltage detection value VC detected by the third voltage sensor 63.

[0039] When the first, second, and third main switches SMR1, SMR2, and SMR3 are not open faults, the voltage detection values ​​VA, VB, and VC of the respective voltage sensors 61, 62, and 63 are low, close to zero. On the other hand, when the first, second, and third main switches SMR1, SMR2, and SMR3 are open faults, the voltage detection values ​​VA, VB, and VC of the voltage sensors 61, 62, and 63 corresponding to these switches are higher than when there are no open faults. Therefore, by comparing the voltage detection values ​​VA, VB, and VC with the voltage threshold Vjd, it is possible to determine whether the first, second, and third main switches SMR1, SMR2, and SMR3 are open faults.

[0040] In step S10, if the control device 50 determines that none of the first, second, and third main switches SMR1, SMR2, and SMR3 are open faults, it terminates the overvoltage reduction process. In this embodiment, the process in step S10 corresponds to the "determination unit".

[0041] In step S10, if the control device 50 determines that any of the first, second, or third main switches SMR1, SMR2, or SMR3 has an open fault, the process proceeds to step S11. If any of the first, second, or third main switches SMR1, SMR2, or SMR3 has an open fault, the closed circuit formed for the vehicle to run, including the second battery 12, the first battery 11, the inverter 10, and the armature winding 42, is disconnected.

[0042] In step S11, the control device 50 outputs an ON command to the motor-side switch 20. This ensures a closed circuit separate from the closed circuit formed for the vehicle to run. Specifically, if the first main switch SMR1 or the third main switch SMR3 has an open fault, a closed circuit is formed including the second battery 12, the armature winding 42, the upper arm switch SWH or upper arm diode DH, the smoothing capacitor 13, and the low-potential path 22. If the second main switch SMR2 ​​has an open fault, a closed circuit is formed including the first battery 11, the high-potential path 21, the upper arm switch SWH or upper arm diode DH, and the armature winding 42. As a result, the current flowing through the smoothing capacitor 13 is reduced, and the voltage rise across the smoothing capacitor 13 is reduced. The process then proceeds to step S12.

[0043] In step S12, the control device 50 performs a short-circuit control process (ASC: Active Short Circuit; hereinafter referred to as ASC control process). The ASC control process is a control in which the control device 50 outputs an ON command to the switch on one arm of the switches in each phase of the inverter 10, and outputs an OFF command to the switch on the other arm. This forms a closed circuit between the armature winding 42 and the inverter 10, and the current flowing through the smoothing capacitor 13 can be reduced. As a result, the rise in voltage across the smoothing capacitor 13 is reduced. The process then proceeds to step S13.

[0044] In step S13, the control device 50 determines whether or not the rotor has stopped rotating. The control device 50 can determine whether or not the rotor has stopped rotating based, for example, on the electrical angular velocity.

[0045] When the control device 50 determines that the rotation of the rotor has stopped, it proceeds to step S14. In step S14, the control device 50 outputs an off command to the motor side switch 20. As a result, the closed circuit formed in step S11 is interrupted between the storage batteries 11 and 12 side and the inverter 10 side. Then, it proceeds to step S15.

[0046] In step S15, the control device 50 outputs an on command to the discharge switch 40. As a result, a closed circuit including the smoothing capacitor 13 and the discharge resistor 14 is formed. Consequently, current flows from the smoothing capacitor 13 to the discharge resistor 14, and the smoothing capacitor 13 is discharged. Also, in step S14, since the closed circuit formed in step S11 is interrupted, it is possible to prevent current from flowing from the first and second storage batteries 11 and 12 to the discharge resistor 14.

[0047] The circuit diagrams until the control device 50 performs overvoltage reduction processing and the discharge of the smoothing capacitor 13 is completed will be described using FIGS. 3 to 6. Also, in FIGS. 3 to 6, the case where the first main switch SMR1 has an open fault and an on command is output to the upper arm switches SWH of each phase in the ASC control process is shown as an example. In FIGS. 3 to 6, the illustration of each sensor and the first and second motor side switches 20A and 20B etc. is simplified.

[0048] FIG. 3 shows a state where the vehicle is running in a series connection state when no open fault has occurred (hereinafter, normal time). In this case, the first, second, and third main switches SMR1, SMR2, and SMR3 are in the on state. Also, the motor side switch 20, the bypass switch 30, and the discharge switch 40 are in the off state. As a result, a closed circuit including the first and second storage batteries 11 and 12, the high potential path 21, the inverter 10, the armature winding 42, and the low potential path 22 is formed, and the first and second storage batteries 11 and 12 supply power to the armature winding 42 via the inverter 10.

[0049] As shown in Figure 4, if the first main switch SMR1 fails in an open circuit, the closed circuit supplying power from the first and second batteries 11 and 12 to the inverter 10 is interrupted. This causes an overvoltage to occur in the system. In this case, the closed circuit including the motor 41 consists only of the armature winding 42, the inverter 10, and the smoothing capacitor 13, causing the voltage across the smoothing capacitor 13 to rise.

[0050] When the control device 50 determines that the first main switch SMR1 has an open fault, it outputs an ON command to the motor-side switch 20. As a result, the closed circuit including the armature winding 42 includes not only the armature winding 42, inverter 10, and smoothing capacitor 13, but also the second storage battery 12, armature winding 42, inverter 10, smoothing capacitor 13, and low-potential path 22. This reduces the degree of voltage increase even if the voltage across the smoothing capacitor 13 rises.

[0051] As shown in Figure 5, the control device 50 performs ASC control processing when it determines that the first main switch SMR1 has an open fault. In the example shown in Figure 5, the control device 50 outputs an ON command to the upper arm switch SWH for each phase and an OFF command to the lower arm switch SWL. This forms a closed circuit including the armature winding 42 and the upper arm switch SWH or upper arm diode DH, thereby reducing the current flowing through the smoothing capacitor 13. As a result, the voltage rise of the smoothing capacitor 13 is reduced.

[0052] After the rotor stops rotating, the control device 50 outputs an off command to the motor-side switch 20, as shown in Figure 6, before outputting an on command to the discharge switch 40. This prevents the closed circuit, which includes the second battery 12, armature winding 42, upper arm switch SWH, discharge resistor 14, and discharge switch 40, from being turned on. As a result, it is possible to prevent current from flowing from the second battery 12 to the discharge resistor 14.

[0053] According to the embodiment described above, the following effects can be obtained.

[0054] The control device 50 switches the motor-side switch 20 to the ON state if it determines that any of the first, second, or third main switches SMR1, SMR2, or SMR3 has an open fault. This allows for the rapid establishment of a closed circuit including the first battery 11 or the second battery 12, the inverter 10, and the armature winding 42, thereby reducing the overvoltage generated in the system. As a result, the voltage rise of the smoothing capacitor 13 is reduced. Consequently, the system can employ a smoothing capacitor 13 with a lower voltage rating.

[0055] If the control device 50 determines that any of the first, second, or third main switches SMR1, SMR2, or SMR3 has an open fault, it performs ASC control processing while ensuring a closed circuit including the first battery 11 or the second battery 12, the inverter 10, and the armature winding 42. This quickly reduces the voltage rise of the smoothing capacitor 13 due to overvoltage.

[0056] The voltage of the smoothing capacitor 13 is reduced to the voltage of the first battery 11 or the second battery 12 by ASC control processing, etc. Therefore, when the control device 50 turns on the discharge switch 40, the discharge time of the smoothing capacitor 13 by the discharge resistor 14 can be shortened.

[0057] <Modification of the First Embodiment> In step S10 of Figure 2, the control device 50 may determine whether any of the first, second, and third main switches SMR1, SMR2, and SMR3 are open faults based on the detection values ​​of the first, second, and third temperature sensors 66, 67, and 68, instead of the detection values ​​of the first, second, and third voltage sensors 61, 62, and 63.

[0058] For example, in step S10, if the control device 50 determines that the input temperature detection value TA of the first main switch SMR1 is higher than the temperature threshold Tjd, it determines that the first main switch SMR1 has an open fault. On the other hand, if the control device 50 determines that the input temperature detection value TA of the first main switch is less than or equal to the temperature threshold Tjd, it determines that the first main switch SMR1 has not an open fault.

[0059] In step S10, one example of a method for determining whether the second main switch SMR2 ​​is experiencing an open fault is to replace the first main switch SMR1 with the second main switch SMR2, replace the first temperature sensor 66 with the second temperature sensor 67, and replace the temperature detection value TA detected by the first temperature sensor 66 with the temperature detection value TB detected by the second temperature sensor 67.

[0060] In step S10, one example of a method for determining whether the third main switch SMR3 is experiencing an open fault is to replace the first main switch SMR1 with the third main switch SMR3, replace the first temperature sensor 66 with the third temperature sensor 68, and replace the temperature detection value TA detected by the first temperature sensor 66 with the temperature detection value TC detected by the third temperature sensor 68.

[0061] The situation just before the first, second, and third main switches SMR1, SMR2, and SMR3 experience an open circuit failure is one in which the cross-sectional area of ​​the current path in the first, second, and third main switches SMR1, SMR2, and SMR3 becomes excessively small. In such a situation, the resistance values ​​of the first, second, and third main switches SMR1, SMR2, and SMR3 increase. This increase in resistance leads to a temperature rise in the first, second, and third main switches SMR1, SMR2, and SMR3. In light of this, a situation in which the temperature detection values ​​TA, TB, and TC exceed the temperature threshold Tjd can be determined to be a situation in which the first, second, and third main switches SMR1, SMR2, and SMR3 have effectively experienced an open circuit failure.

[0062] In step S10 of Figure 2, the control device 50 may determine whether the first, second, and third main switches SMR1, SMR2, and SMR3 are experiencing an open fault based on the detected value of the current sensor 64. An example of a method for determining whether an open fault is occurring will be described below.

[0063] For example, if the control device 50 determines that the detected current IA flowing through the input first battery 11 is less than the current threshold Ijd, it determines that one of the first, second, or third main switches SMR1, SMR2, or SMR3 is open fault. On the other hand, if the control device 50 determines that the detected current IA flowing through the input first battery 11 is greater than or equal to the current threshold Ijd, it determines that the first, second, or third main switches SMR1, SMR2, or SMR3 are not open fault.

[0064] If any of the first, second, or third main switches SMR1, SMR2, or SMR3 has an open fault, the closed circuit necessary for the vehicle to run is interrupted, and no current flows. As a result, the current sensor 64 can no longer detect the current detection value IA flowing to the first battery 11. In other words, the current detection value IA when there is an open fault is smaller than the current detection value IA when there is no open fault. Therefore, by comparing the current detection value IA with the current threshold value Ijd, it is possible to determine that any of the first, second, or third main switches SMR1, SMR2, or SMR3 has an open fault.

[0065] As shown in Figure 7, a second current sensor 164 may be provided on the side of the second battery 12 that is closer to the first main switch SMR1 than to the second battery 12 in the battery inter-battery path 23. In this case, the second current sensor 164 detects a current detection value IB, which is the current flowing through the second battery 12. The detection value of the second current sensor 164 is input to the control device 50. One example of a method for determining whether the first, second, and third main switches SMR1, SMR2, and SMR3 are experiencing an open fault is to replace the first battery 11 with the second battery 12 and replace the current detection value IA detected by the current sensor 64 with the current detection value IB detected by the second current sensor 164.

[0066] As shown in Figure 7, the system may also include a fourth voltage sensor 161 and a fifth voltage sensor 162. The fourth voltage sensor 161 detects a voltage detection value VD, which is the terminal voltage of the series connection of the first and second storage batteries 11 and 12. The fifth voltage sensor 162 detects a voltage detection value VE, which is the terminal voltage of the smoothing capacitor 13. The detection values ​​of the fourth and fifth voltage sensors 161 and 162 are input to the control device 50.

[0067] In step S10, as shown in Figure 2, the control device 50 may determine whether the first, second, and third main switches SMR1, SMR2, and SMR3 are experiencing an open fault based on the detection values ​​of the fourth and fifth voltage sensors 161 and 162 input to the control device 50. For example, the control device 50 determines whether any of the first, second, and third main switches SMR1, SMR2, and SMR3 are experiencing an open fault based on the voltage detection values ​​VD and VE. For example, the control device 50 calculates the voltage VF, which is the difference between the voltage detection value VD and the voltage detection value VE. If the control device 50 determines that the calculated voltage VF is higher than the voltage threshold Vjd, it determines that any of the first, second, and third main switches SMR1, SMR2, and SMR3 are experiencing an open fault. On the other hand, if the control device 50 determines that the calculated voltage VF is less than or equal to the voltage threshold Vjd, it determines that the first, second, and third main switches SMR1, SMR2, and SMR3 are not open faults.

[0068] If the first, second, and third main switches SMR1, SMR2, and SMR3 are not open faults, a closed circuit is formed including the second battery 12, the first battery 11, and the smoothing capacitor 13, so the difference between the voltage detection value VD and the voltage detection value VE is small. On the other hand, if any of the first, second, and third main switches SMR1, SMR2, and SMR3 are open faults, the closed circuit is interrupted, and the voltage detection value VD of the series connection of the first and second batteries 11 and 12 becomes smaller than the voltage detection value VE of the smoothing capacitor 13. Therefore, the control device 50 can determine that any of the first, second, and third main switches SMR1, SMR2, and SMR3 are open faults by calculating the voltage VF.

[0069] In the ASC control process performed in step S12 of Figure 2, the control device 50 may output an ON command to the two-phase switch of either one of the switches. Specifically, the control device 50 outputs an ON command to turn on the lower arm switches SWL of the U-phase and V-phase. The control device 50 also outputs an OFF command to the lower arm switch SWL of the V-phase and the upper arm switches SWH of each phase, and performs the ASC control process. In this case, a closed circuit is formed including the lower arm switch SWL or lower arm diode DL of the U-phase, the armature winding 42, and the lower arm switch SWL or lower arm diode DL of the V-phase, thereby reducing the current flowing through the smoothing capacitor 13. As a result, the rise in voltage across the smoothing capacitor 13 due to the induced voltage generated in each armature winding 42 is reduced.

[0070] - In step S13 of Figure 2, if the control device 50 determines that the rotor's rotational speed has fallen to or below a predetermined rotational speed that is higher than 0, it may proceed to step S14. In other words, once the rotor's rotational speed has decreased to a certain extent, it may proceed to step S14 without waiting for the rotor to stop rotating.

[0071] <Second Embodiment> The second embodiment will now be described, focusing on the differences from the first embodiment, with reference to the drawings. In this embodiment, as shown in Figure 8, the system includes a bypass switch 130 that connects to the positive terminal of the first battery 11 and the positive terminal of the second battery 12, instead of a bypass switch 30 that connects the negative terminal of the first battery 11 and the negative terminal of the second battery 12.

[0072] In this embodiment, the bypass switch 30 is a mechanical relay. However, the bypass switch 30 is not limited to a mechanical relay; for example, it may be a semiconductor switching element.

[0073] The motor electrical path 24 is connected to the first battery 11 side and the neutral point O of the battery-to-battery path 23, which is further along than the third main switch SMR3. Specifically, the first motor-side switch 20A has its collector facing the negative terminal side of the first battery 11, and the first motor-side switch 20A has its emitter facing the emitter of the second motor-side switch 20B. The second motor-side switch 20B has its collector facing the neutral point O.

[0074] According to the embodiment described above, effects similar to those of the first embodiment can be achieved.

[0075] <Third Embodiment> The third embodiment will now be described, focusing on the differences from the first embodiment, with reference to the drawings. In this embodiment, the control device 50 performs a current suppression process to suppress the generation of inrush current in the overvoltage reduction process (see Figure 2).

[0076] If any of the first, second, or third main switches SMR1, SMR2, or SMR3 are open fault, the control device 50 outputs an ON command to the motor-side switch 20 to secure a new closed circuit and reduce overvoltage (see Figure 4). In this case, there is a concern that an inrush current will flow from the armature winding 42 to the motor-side switch 20. Therefore, the control device 50 performs a current suppression process.

[0077] Next, the overvoltage reduction process of the control device 50, including the current suppression process, will be explained using the flowchart in Figure 9. In Figure 9, the same steps as those in Figure 2 are given the same step numbers for convenience.

[0078] In step S20, the control device 50 outputs a half-on command to the motor-side switch 20.

[0079] Half-on refers to the state in which the gate voltage of a switch reaches the voltage required to turn on the switch in the saturation region. The saturation region is the region in the output characteristics where the collector-emitter voltage Vce and collector current Ice of a switch are related, where the collector current Ice is approximately constant regardless of the magnitude of the voltage Vce. The voltage drop in a half-on switch is greater than the voltage drop in a fully-on switch.

[0080] Full-on refers to the state in which the gate voltage of the switch becomes the voltage that turns on the switch in the non-saturation region. The non-saturation region is the region in the output characteristics, where the collector-emitter voltage Vce and collector current Ice of the switch are related, in which the collector current Ice increases as the voltage Vce increases. In a full-on state, the on-resistance of the switch is close to zero. The on command in the first embodiment is the full-on command in this embodiment.

[0081] When the motor-side switch 20 is set to a half-on state, a closed circuit separate from the closed circuit formed for the vehicle to run (see Figure 3) is secured. Specifically, if the first main switch SMR1 or the third main switch SMR3 has an open fault, a closed circuit is formed that includes the second battery 12, the armature winding 42, the upper arm switch SWH or the upper arm diode DH, the smoothing capacitor 13, and the low-potential path 22. If the second main switch SMR2 ​​has an open fault, a closed circuit is formed that includes the first battery 11, the high-potential path 21, the upper arm switch SWH or the upper arm diode DH, and the armature winding 42.

[0082] In this case, the on-resistance of the motor-side switch 20 is higher than the on-resistance when fully on. Therefore, the inrush current of the motor-side switch 20 that occurs when a closed circuit is formed can be suppressed. Then, proceed to step S21.

[0083] In step S21, the control device 50 determines whether or not the inrush current generated in the motor-side switch 20 has been suppressed. An example of a method for determining whether or not the inrush current generated in the motor-side switch 20 has been suppressed will be described below.

[0084] In the first example of the determination method, the system is equipped with a current sensor that detects the current value of the motor-side switch 20. If the control device 50 determines that the current value of the motor-side switch 20 obtained from the current sensor is higher than the current threshold, it determines that an inrush current is flowing through the motor-side switch 20. On the other hand, if the control device 50 determines that the current value of the motor-side switch 20 obtained from the current sensor is less than or equal to the current threshold, it determines that the inrush current flowing through the motor-side switch 20 has been suppressed.

[0085] In the second example of the determination method, the control device 50 determines whether a certain period of time has elapsed since the output of the half-on command to the motor-side switch 20. In this case, the control device 50 has a preset period of time from the output of the half-on command to the motor-side switch 10 until it is assumed that the inrush current will be suppressed. If the control device 50 determines that a certain period of time has elapsed since the output of the half-on command, it determines that the inrush current generated in the motor-side switch 20 has been suppressed.

[0086] In step S21, if the control device 50 determines that the inrush current generated in the motor-side switch 20 has been suppressed, it proceeds to step S11. In step S11, the control device 50 outputs a full-on command to the motor-side switch 20. As a result, the motor-side switch 20 is switched from the half-on state to the full-on state.

[0087] The overvoltage reduction control in this embodiment suppresses the inrush current of the motor-side switch 20 that occurs when a closed circuit is formed, while also reducing the voltage rise of the smoothing capacitor 13.

[0088] Furthermore, the configuration of the third embodiment may be applied to the second embodiment.

[0089] <Modification of the Third Embodiment> The control device 50 may intermittently output ON commands (specifically, full ON commands) to the motor-side switch 20 as a current suppression process. An example of a specific current suppression process will be described below.

[0090] In the first example, the control device 50 sets the duty cycle of the motor-side switch 20 based on the current value of the motor-side switch 20 obtained from the current sensor. The duty cycle is the ratio of the ON period Ton of the motor-side switch 20 to one switching period Tsw (Ton / Tsw). For example, the control device 50 should adjust the duty cycle of the motor-side switch 20 closer to 1 as the magnitude (i.e., absolute value) of the acquired current value of the motor-side switch 20 decreases and approaches the judgment threshold.

[0091] In the second example, information linking the elapsed time since the ON command was output to the motor-side switch 20 and the duty cycle of the motor-side switch 20 is pre-stored in the memory unit 52. In this case, the control device 50 intermittently outputs ON commands to the motor-side switch 20 according to the duty cycle calculated based on the counted elapsed time and the linked information.

[0092] <Fourth Embodiment> The fourth embodiment will now be described, focusing on the differences from the third embodiment, with reference to the drawings. In this embodiment, as shown in Figure 10, the control device 50 includes a speed change unit 55 for changing the turn-on speed of the motor-side switch 20 when outputting an ON command to the motor-side switch 20.

[0093] An example of the configuration of the control device 50 will be explained using Figure 10. Since the connection relationships of the first and second motor-side switches 20A and 20B (see Figure 1) connected to the control device 50 are the same, the first motor-side switch 20A is shown as a specific example, and the second motor-side switch 20B is not shown.

[0094] The control device 50 includes a control command unit 54 and a speed change unit 55. The first motor-side switch 20A is turned ON or OFF based on a command from the control command unit 54 via the speed change unit 55.

[0095] The speed change unit 55 includes a constant voltage power supply 70, a first charging switch 71, and a first charging resistor 72. The constant voltage power supply 70 is connected to the gate of the first motor-side switch 20A via the first charging switch 71 and the first charging resistor 72. When the first charging switch 71 is ON, power is supplied to the gate of the first motor-side switch 20A. In this case, the first motor-side switch 20A is switched ON at a first turn-on speed based on the resistance value Ron1 of the first charging resistor 72.

[0096] The speed change unit 55 includes a second charging switch 73 and a second charging resistor 74. The constant voltage power supply 70 is connected to the gate of the first motor-side switch 20A via the second charging switch 73 and the second charging resistor 74. When the second charging switch 73 is ON, power is supplied to the gate of the first motor-side switch 20A. In this case, the first motor-side switch 20A is switched ON at a second turn-on speed based on the resistance value Ron2 of the second charging resistor 74.

[0097] Here, the resistance value Ron1 of the first charging resistor 72 is greater than the resistance value Ron2 of the second charging resistor 74. In this case, the charging current supplied to the gate of the motor-side switch 20 is greater with the first charging resistor 72 than with the second charging resistor 74. Therefore, when power is supplied to the gate of the motor-side switch 20 by the first charging resistor 72, the 20-turn-on time of the motor-side switch can be extended.

[0098] The speed change unit 55 includes an open switch 75 and an open resistor 76. The gate of the first motor-side switch 20A is connected to the emitter of the first motor-side switch 20A via the open switch 75 and the open resistor 76. When the open switch 75 is turned ON, the charge on the gate of the first motor-side switch 20A is discharged. In this case, the first motor-side switch 20A is switched OFF at a speed based on the resistance value Roff of the open resistor 76.

[0099] Next, the overvoltage reduction process of the control device 50 will be explained using the flowchart in Figure 11. In Figure 11, the same step numbers are used for processes that are the same as those in Figure 9 for convenience.

[0100] In step S30, the control command unit 54 outputs an ON command to the first charging switch 71 and OFF commands to the second charging switch 73 and the open switch 75. In this case, the first charging switch 71 is switched to the ON state, and power is supplied to the gate of the first motor-side switch 20A at the first turn-on speed. In this case, the turn-on time of the motor-side switch 20 is extended, and a longer period of time with higher on-resistance than the full-on state can be secured. As a result, when a closed circuit including the motor-side switch 20 is formed, the inrush current generated in the motor-side switch 20 can be suppressed.

[0101] In step S31, the control command unit 54 outputs an OFF command to the first charging switch 71 and an ON command to the second charging switch 73. In this case, the second charging switch 73 is switched to the ON state. As a result, power is supplied to the gate of the motor-side switch 20 at the second turn-on speed, and the motor-side switch 20 is switched to the ON state.

[0102] In step S32, the control device 50 outputs an off command to the motor-side switch 20. Specifically, the control command unit 54 outputs an off command to the second charging switch 73. The control command unit 54 also outputs an on command to the open switch 75. As a result, the charge on the gate of the motor-side switch 20 is discharged via the open resistor 76, and the motor-side switch 20 is switched to the off state.

[0103] Furthermore, the configuration of the fourth embodiment may be applied to the third embodiment.

[0104] <Modification of the fourth embodiment> The number of charging switches and charging resistors connected to the constant voltage power supply 70 and the gate of the first motor-side switch 20A is not limited to two, but may be three or more.

[0105] <Fifth Embodiment> The fifth embodiment will now be described, focusing on the differences from the third embodiment, with reference to the drawings. In this embodiment, the motor-side switch 20 is configured to adjust the current flowing through it, and the motor-side switch 20 is equipped with a plurality of individual switches 120A and 120B.

[0106] As shown in Figure 12, the first motor-side switch 20A is a parallel connection of multiple first individual switches 120A. Similarly, the second motor-side switch 20B is a parallel connection of multiple second individual switches 120B. In this embodiment, the first motor-side switch 20A comprises three first individual switches 120A, and the second motor-side switch 20B comprises three second individual switches 120B.

[0107] In this embodiment, the first and second individual switches 120A and 120B are semiconductor switching elements, specifically IGBTs. Freewheeling diodes D1 and D2 are connected in antiparallel to the first and second individual switches 120A and 120B.

[0108] When charging the first and second batteries 11 and 12 with a low-voltage charger, the control device 50 connects the first and second energy storage units in parallel before charging. In this case, the control device 50 outputs ON commands to the first and second main switches SMR1 and SMR2, the motor-side switch 20, the bypass switch 30, and the upper arm switch SWH (see Figure 1).

[0109] In this case, the control device 50 outputs an ON command to all of the first and second individual switches 120A and 120B. This results in the lowest resistance in the motor-side switch 20. Therefore, the first and second storage batteries 11 and 12 are charged with the least power loss in the motor-side switch 20.

[0110] Next, the overvoltage reduction process of the control device 50 will be explained using the flowchart in Figure 9.

[0111] In step S20, the control device 50 outputs an ON command to one of the first individual switches 120A of the first motor-side switches 20A (for example, any one of them). The control device 50 also outputs an ON command to one of the second individual switches 120B of the second motor-side switches 20B (for example, any one of them). This ensures a closed circuit separate from the closed circuit formed for the vehicle to run. In this secured closed circuit, the resistance of the first and second motor-side switches 20A and 20B is high, resulting in high power loss. Therefore, the generation of inrush current in the motor-side switches 20 can be suppressed.

[0112] In step S11, the control device 50 outputs an ON command to the motor-side switch 20. In this embodiment, the control device 50 outputs ON commands to all of the first and second individual switches 120A and 120B.

[0113] In step S14, the control device 50 outputs an off command to the motor-side switch 20. In this embodiment, the control device 50 outputs off commands to all of the first and second individual switches 120A and 120B.

[0114] <Modification of the Fifth Embodiment> In the motor-side switch 20, the first individual switch 120A and the second individual switch 120B may be connected in series as shown in Figure 13. In this case, the series connection of the first individual switch 120A and the second individual switch 120B is connected in parallel. In this case, in step S20, the control device 50 only needs to output an ON command to one of the series connection units composed of the first individual switch 120A and the second individual switch 120B.

[0115] <Sixth Embodiment> The sixth embodiment will now be described, focusing on the differences from the first embodiment, with reference to the drawings. In this embodiment, the control device 50 discharges the smoothing capacitor 13 using the upper and lower arm switches SWH and SWL of the inverter 10 during the overvoltage reduction process (see Figure 2).

[0116] The overvoltage reduction process will be explained using the flowchart in Figure 14. In Figure 14, the same steps as those in Figure 2 are given the same step numbers for convenience.

[0117] After step S14 is completed, in step S40, the control device 50 controls the switching of the upper and lower arm switches SWH and SWL in order to discharge the smoothing capacitor 13.

[0118] Specifically, the control device 50 intermittently outputs ON commands to the upper and lower arm switches SWH and SWL such that the ON periods of at least one phase among the U to W phases overlap. When the ON periods of the upper and lower arm switches SWH and SWL overlap, a closed circuit is formed including the smoothing capacitor 13, the upper arm switch SWH, and the lower arm switch SWL. As a result, current flows from the smoothing capacitor 13 to the upper and lower arm switches SWH and SWL, and the smoothing capacitor 13 is discharged.

[0119] In step S40, the control device 50 may, for example, output an ON command to one of the upper and lower arm switches SWH and SWL, and intermittently output ON commands to the other switch. Specifically, for example, the control device 50 outputs an ON command to the upper arm switch SWH and intermittently outputs ON commands to the lower arm switch SWL.

[0120] In this embodiment, the system does not need to include a series connection of the discharge resistor 14 and the discharge switch 40.

[0121] As described above, this embodiment can achieve effects similar to those of the first embodiment. The processing of this embodiment may also be applied to the second to fifth embodiments.

[0122] <Other Embodiments> Each of the above embodiments may be implemented with the following modifications.

[0123] The installation positions of the discharge switch 40 and the discharge resistor 14 may be reversed. Specifically, the collector of the discharge switch 40 is connected to the first terminal of the smoothing capacitor 13, and the emitter of the discharge switch 40 is connected to the first terminal of the discharge resistor 14. Also, the second terminal of the discharge resistor 14 is connected to the second terminal of the smoothing capacitor 13.

[0124] The first motor-side switch 20A and the second motor-side switch 20B that constitute the motor-side switch 20 are not limited to being connected collector to collector as shown in Figure 1, but may also be connected emitters to emitters.

[0125] The armature windings 42 of the motor 41 are not limited to a star connection, but may be configured as, for example, a delta connection. In this case, the motor electrical path 24, which was connected to the neutral point O, is connected to the connection point between the armature windings 42.

[0126] The upper and lower arm switches SWH and SWL are not limited to IGBTs, but may also be, for example, N-channel MOSFETs. In this case, the high-potential terminal is the drain, and the low-potential terminal is the source. The upper and lower arm switches have body diodes.

[0127] The system is not limited to being installed in vehicles; it may also be installed in other mobile objects such as aircraft or ships. If the mobile object is an aircraft, the rotating electric motor will be the aircraft's flight power source; if the mobile object is a ship, the rotating electric motor will be the ship's navigation power source. Furthermore, the system is not limited to being installed in a mobile object; it can also be used as a stationary power source.

[0128] In this disclosure or claims, the term "processor" means one or more hardware processors configured to execute processing defined by computer program code (i.e., one or more instructions of a computer program) contained in a computer program by reading the computer program code each time. In other words, a "processor" is a hardware device that executes one or more programmed processes. Therefore, computer program code can also be said to be software that can define the processing of the processor according to its content. A "processor" can be a general-purpose or specific-purpose processor, and may be, but is not limited to, a CPU, microprocessor, GPU, and DFP (Data Flow Processor).

[0129] In this disclosure or claims, the term “memory” means one or more hardware memories that are non-transitional tangible recording media configured to record computer program code and / or data in a manner accessible from a processor. “Memory” can be implemented by memory technology such as SRAM, SDRAM, non-volatile / flash type memory, or other types of memory. The computer program code that constitutes the program is recorded in memory and executed by a processor, thereby enabling the processor to perform the various functions described above.

[0130] In this disclosure or claims, the term “circuit” refers to one or more logic circuits as hardware, configured to perform specific processing defined by a pre-designed circuit configuration. In other words (and, in contrast to “processor”), “circuit” in this disclosure or claims refers to a hardware device that performs specific processing based on a circuit configuration, rather than processing defined by software such as the computer program code described above. For example, “circuit” may include custom ICs such as ASICs (Application Specific Integrated Circuits) and FPGAs (Field Programmable Gate Arrays) designed with Hardware Description Language (HDL). That is, “circuit” in this disclosure or claims includes all hardware circuits except for the processors described above that perform processing by reading computer program code.

[0131] In this disclosure or claims, the expression "at least one of the circuit and processor" should be interpreted as disjunctive (logical OR) and not as "at least one circuit and at least one processor." Therefore, in this disclosure or claims, "at least one of the circuit and processor causes the control device to perform functions" includes cases where the circuit alone causes the control device to perform all functions. Also, "at least one of the circuit and processor causes the control device to perform functions" includes cases where the processor alone causes the control device to perform all functions. Furthermore, "at least one of the circuit and processor causes the control device to perform functions" includes cases where the circuit causes the control device to perform some functions and the processor causes the control device to perform the remaining functions. In the last example, for example, if the control device performs functions A to C, functions A and B may be implemented by the circuit, and the remaining function C may be implemented by the processor.

[0132] The following describes the characteristic configurations extracted from each of the embodiments described above. [Configuration 1] A control device (50) applied to a system comprising: a first energy storage unit (11) and a second energy storage unit (12); an inverter (10) having a multi-phase upper arm switch (SWH) and a lower arm switch (SWL); a high-potential path (21) connecting the high-potential side terminal of the upper arm switch to the positive terminal of the first energy storage unit; a low-potential path (22) connecting the low-potential side terminal of the lower arm switch to the negative terminal of the second energy storage unit; a smoothing capacitor (13) connected in parallel to the series connection of the upper arm switch and the lower arm switch; and a motor (41) having an armature winding (42) connected to the low-potential side terminal of the upper arm switch and the high-potential side terminal of the lower arm switch, wherein the system comprises: an inter-energy storage unit switch (SMR3) provided in the inter-energy storage unit electrical path (23) connecting the negative terminal of the first energy storage unit and the positive terminal of the second energy storage unit; The control device comprises: a motor-side switch (20) provided in a motor electrical path (24) connecting the armature winding and the electrical path between the energy storage units; main switches (SMR1, SMR2) provided in at least one of the high-potential path and the low-potential path; and a bypass switch (30) that makes an electrical connection between at least one of the following: an electrical connection between the positive terminals of the first energy storage unit and the second energy storage unit, and an electrical connection between the negative terminals of the first energy storage unit and the second energy storage unit. The control device comprises: a switch control unit that controls the upper and lower arm switches, the energy storage unit switch, the motor-side switch, the main switch, and the bypass switch; and a determination unit that determines whether an open fault has occurred in the main switch or the energy storage unit switch when the switch control unit outputs an ON command to the main switch and the energy storage unit switch. The control device outputs an ON command to the motor-side switch when the switch control unit determines that the main switch or the energy storage unit switch has an open fault.[Configuration 2] The control device according to Configuration 1, wherein the switch control unit, when it is determined that the main switch or the inter-energy storage unit switch is in an open fault, outputs an ON command to the motor-side switch and performs a current suppression process to suppress the inrush current flowing through the motor electrical path. [Configuration 3] The control device according to Configuration 2, wherein the switch control unit performs a process of outputting a half-ON command to the motor-side switch as the current suppression process. [Configuration 4] The control device according to Configuration 2, wherein the switch control unit performs a process of intermittently outputting ON commands to the motor-side switch as the current suppression process. [Configuration 5] The control device according to Configuration 2, wherein the switch control unit includes a speed change unit (55) for adjusting the turn-on speed of the motor-side switch, the speed change unit can change the turn-on speed between a first speed and a second speed higher than the first speed, and the switch control unit performs a process of outputting an ON command to the motor-side switch at the first speed, and then outputting an ON command to the motor-side switch at the second speed as the current suppression process. [Configuration 6] The motor-side switch is a parallel connection of a plurality of individual switches (120A, 120B), and the switch control unit performs a process as the current suppression process, which involves outputting an ON command to some of the plurality of individual switches, and then outputting an ON command to all of the individual switches, as described in Configuration 2. [Configuration 7] The control device according to any one of Configurations 1 to 6, wherein the switch control unit performs a short-circuit control process, which involves outputting an ON command to at least two phases of the upper arm switch or at least two phases of the lower arm switch, when it is determined that an open fault has occurred. [Configuration 8] The control device according to Configuration 7, wherein the switch control unit performs a process, which involves outputting an ON command to all phases of the upper arm switch or all phases of the lower arm switch, as the short-circuit control process, when it is determined that an open fault has occurred.[Configuration 9] The control device according to Configuration 7 or 8, wherein the system comprises a series connection of a discharge resistor (14) and a discharge switch (40), the series connection of the discharge resistor and the discharge switch is connected in parallel to the smoothing capacitor, and the switch control unit, when it determines that the rotational speed of the rotor of the motor has fallen below a predetermined rotational speed while the short-circuit control process is being executed, outputs an off command to the motor-side switch and then outputs an on command to the discharge switch. [Configuration 10] The control device according to Configuration 7 or 8, when it determines that the rotational speed of the rotor of the motor has fallen below a predetermined rotational speed while the short-circuit control process is being executed, outputs an off command to the motor-side switch and then outputs an on command to at least one phase of the upper and lower arm switches in order to discharge the smoothing capacitor. [Configuration 11] The control device according to Configuration 9 or 10, wherein the predetermined rotational speed is 0. [Configuration 12] The control device according to any one of Configurations 1 to 11, wherein the determination unit determines that an open fault has occurred in the main switch or the inter-energy storage unit switch when the switch control unit is outputting an ON command to the main switch and the inter-energy storage unit switch, and the current flowing through the main switch or the inter-energy storage unit switch is less than a current threshold. [Configuration 13] The control device according to any one of Configurations 1 to 11, wherein the determination unit determines that an open fault has occurred in the main switch or the inter-energy storage unit switch when the switch control unit is outputting an ON command to the main switch and the inter-energy storage unit switch, and the potential difference between the first and second ends of the main switch or the potential difference between the first and second ends of the inter-energy storage unit switch is higher than a voltage threshold. [Configuration 14] The control device according to any one of Configurations 1 to 11, wherein the determination unit determines that an open fault has occurred in the main switch or the inter-energy storage unit switch when the switch control unit has output an ON command to the main switch and the inter-energy storage unit switch, and the temperature of the main switch or the inter-energy storage unit switch is higher than a temperature threshold.[Configuration 15] The motor electrical path is connected to the first energy storage unit side of the inter-energy storage unit electrical path than the inter-energy storage unit switch, and the bypass switch connects the positive terminal of the first energy storage unit to the positive terminal of the second energy storage unit, as described in any one of Configurations 1 to 14. [Configuration 16] The motor electrical path is connected to the second energy storage unit side of the inter-energy storage unit electrical path than the inter-energy storage unit switch, and the bypass switch connects the negative terminal of the first energy storage unit to the negative terminal of the second energy storage unit, as described in any one of Configurations 1 to 14.

[0133] This disclosure is described in accordance with the embodiments, but it is understood that this disclosure is not limited to such embodiments or structures. This disclosure also includes various modifications and variations within the equivalence. In addition, various combinations and forms, as well as other combinations and forms that include only one, more, or fewer of those elements, fall within the scope and concept of this disclosure.

Claims

1. A control device (50) applied to a system comprising: a first energy storage unit (11) and a second energy storage unit (12); an inverter (10) having a multi-phase upper arm switch (SWH) and a lower arm switch (SWL); a high-potential path (21) connecting the high-potential terminal of the upper arm switch to the positive terminal of the first energy storage unit; a low-potential path (22) connecting the low-potential terminal of the lower arm switch to the negative terminal of the second energy storage unit; a smoothing capacitor (13) connected in parallel to the series connection of the upper arm switch and the lower arm switch; and a motor (41) having an armature winding (42) connected to the low-potential terminal of the upper arm switch and the high-potential terminal of the lower arm switch, wherein the system comprises: an inter-energy storage unit switch (SMR3) provided in the inter-energy storage unit electrical path (23) connecting the negative terminal of the first energy storage unit and the positive terminal of the second energy storage unit; The control device comprises: a motor-side switch (20) provided in a motor electrical path (24) connecting the armature winding and the electrical path between the energy storage units; main switches (SMR1, SMR2) provided in at least one of the high-potential path and the low-potential path; and a bypass switch (30) that makes an electrical connection between at least one of the following: an electrical connection between the positive terminals of the first energy storage unit and the second energy storage unit, and an electrical connection between the negative terminals of the first energy storage unit and the second energy storage unit. The control device comprises: a switch control unit that controls the upper and lower arm switches, the energy storage unit switch, the motor-side switch, the main switch, and the bypass switch; and a determination unit that determines whether an open fault has occurred in the main switch or the energy storage unit switch when the switch control unit outputs an ON command to the main switch and the energy storage unit switch. The control device outputs an ON command to the motor-side switch when the switch control unit determines that the main switch or the energy storage unit switch has an open fault.

2. The control device according to claim 1, wherein the switch control unit, when it is determined that the main switch or the inter-energy storage unit switch is in an open fault, performs a current suppression process to suppress the inrush current flowing through the motor electrical path when it outputs an ON command to the motor-side switch.

3. The control device according to claim 2, wherein the switch control unit performs a process of outputting a half-on command to the motor-side switch as the current suppression process.

4. The control device according to claim 2, wherein the switch control unit performs a process of intermittently outputting an ON command to the motor-side switch as the current suppression process.

5. The control device according to claim 2, wherein the switch control unit includes a speed change unit (55) for adjusting the turn-on speed of the motor-side switch, the speed change unit can change the turn-on speed between a first speed and a second speed higher than the first speed, and the switch control unit performs a process as the current suppression process which involves outputting an ON command to the motor-side switch at the first speed, and then outputting an ON command to the motor-side switch at the second speed.

6. The control device according to claim 2, wherein the motor-side switch is a parallel connection of a plurality of individual switches (120A, 120B), and the switch control unit performs a process as the current suppression process which involves outputting an ON command to some of the plurality of individual switches, and then outputting an ON command to all of the individual switches.

7. The control device according to claim 1, wherein the switch control unit, when it determines that the open fault has occurred, performs a short-circuit control process that outputs an ON command to at least two phases of the upper arm switch or at least two phases of the lower arm switch.

8. The control device according to claim 7, wherein, when the switch control unit determines that the open fault has occurred, it performs a process to output an ON command to the upper arm switch for all phases or the lower arm switch for all phases as the short-circuit control process.

9. The control device according to claim 7 or 8, wherein the system comprises a series connection of a discharge resistor (14) and a discharge switch (40), the series connection of the discharge resistor and the discharge switch is connected in parallel to the smoothing capacitor, and the switch control unit, when it determines that the rotational speed of the rotor of the motor has fallen below a predetermined rotational speed while the short-circuit control process is being executed, outputs an off command to the motor-side switch and then outputs an on command to the discharge switch.

10. The control device according to claim 7 or 8, wherein, when the switch control unit determines that the rotational speed of the rotor of the motor has fallen below a predetermined rotational speed while the short-circuit control process is being executed, it outputs an off command to the motor-side switch and then outputs an on command to at least one phase of the upper and lower arm switches in order to discharge the smoothing capacitor.

11. The control device according to claim 9, wherein the predetermined rotational speed is 0.

12. The control device according to claim 1 or any one of claims 7 to 8, wherein the determination unit determines that an open fault has occurred in the main switch or the inter-energy storage unit switch when the switch control unit has output an ON command to the main switch and the inter-energy storage unit switch, and the current flowing through the main switch or the inter-energy storage unit switch is less than a current threshold.

13. The control device according to claim 1 or any one of claims 7 to 8, wherein the determination unit determines that an open fault has occurred in the main switch or the inter-energy storage unit switch when the switch control unit has output an ON command to the main switch and the inter-energy storage unit switch, and the determination unit determines that the potential difference between the first and second ends of the main switch or the potential difference between the first and second ends of the inter-energy storage unit switch is higher than a voltage threshold.

14. The control device according to claim 1 or any one of claims 7 to 8, wherein the determination unit determines that an open fault has occurred in the main switch or the inter-energy storage unit switch when the switch control unit has output an ON command to the main switch and the inter-energy storage unit switch, and the determination unit determines that the temperature of the main switch or the inter-energy storage unit switch is higher than a temperature threshold.

15. The control device according to claim 1 or any one of claims 7 to 8, wherein the motor electrical path is connected to the first energy storage unit side of the inter-energy storage unit electrical path than the inter-energy storage unit switch, and the bypass switch connects the positive terminal of the first energy storage unit to the positive terminal of the second energy storage unit.

16. The control device according to claim 1 or any one of claims 7 to 8, wherein the motor electrical path is connected to the second energy storage unit side of the inter-energy storage unit electrical path than the inter-energy storage unit switch, and the bypass switch connects the negative terminal of the first energy storage unit to the negative terminal of the second energy storage unit.

17. A program applied to a system comprising: a first energy storage unit (11) and a second energy storage unit (12); an inverter (10) having a multi-phase upper arm switch (SWH) and a lower arm switch (SWL); a high-potential path (21) connecting the high-potential terminal of the upper arm switch to the positive terminal of the first energy storage unit; a low-potential path (22) connecting the low-potential terminal of the lower arm switch to the negative terminal of the second energy storage unit; a smoothing capacitor (13) connected in parallel to the series connection of the upper arm switch and the lower arm switch; and a motor (41) having an armature winding (42) connected to the low-potential terminal of the upper arm switch and the high-potential terminal of the lower arm switch, wherein the system comprises: an inter-energy storage unit switch (SMR3) provided in the inter-energy storage unit electrical path (23) connecting the negative terminal of the first energy storage unit and the positive terminal of the second energy storage unit; The circuit comprises: a motor-side switch (20) provided in the motor electrical path (24) connecting the armature winding and the electrical path between the energy storage units; main switches (SMR1, SMR2) provided in at least one of the high-potential path and the low-potential path; and a bypass switch (30) that makes an electrical connection between at least one of the following: the electrical connection between the positive terminals of the first energy storage unit and the second energy storage unit, and the electrical connection between the negative terminals of the first energy storage unit and the second energy storage unit. At least one of the circuit and processor (51) is made to execute: a switch control process that controls the upper and lower arm switches, the energy storage unit switch, the motor-side switch, the main switch, and the bypass switch; and a determination process that determines whether an open fault has occurred in the main switch or the energy storage unit switch when the switch control process has output an ON command to the main switch and the energy storage unit switch. A program that, in the switch control process described above, outputs an ON command to the motor-side switch if it is determined that the main switch or the switch between the energy storage units is experiencing an open fault.

18. A control method for a control device applied to a system comprising: a first energy storage unit (11) and a second energy storage unit (12); an inverter (10) having a multi-phase upper arm switch (SWH) and a lower arm switch (SWL); a high-potential path (21) connecting the high-potential side terminal of the upper arm switch to the positive terminal of the first energy storage unit; a low-potential path (22) connecting the low-potential side terminal of the lower arm switch to the negative terminal of the second energy storage unit; a smoothing capacitor (13) connected in parallel to the series connection of the upper arm switch and the lower arm switch; and a motor (41) having an armature winding (42) connected to the low-potential side terminal of the upper arm switch and the high-potential side terminal of the lower arm switch, wherein the system comprises: an inter-energy storage unit switch (SMR3) provided in the inter-energy storage unit electrical path (23) connecting the negative terminal of the first energy storage unit and the positive terminal of the second energy storage unit; The circuit comprises: a motor-side switch (20) provided in the motor electrical path (24) connecting the armature winding and the electrical path between the energy storage units; main switches (SMR1, SMR2) provided in at least one of the high-potential path and the low-potential path; and a bypass switch (30) that makes an electrical connection between at least one of the following: the electrical connection between the positive terminals of the first energy storage unit and the second energy storage unit, and the electrical connection between the negative terminals of the first energy storage unit and the second energy storage unit. At least one of the circuit and processor (51) is made to execute: a switch control process that controls the upper and lower arm switches, the energy storage unit switch, the motor-side switch, the main switch, and the bypass switch; and a determination process that determines whether an open fault has occurred in the main switch or the energy storage unit switch when the switch control process has output an ON command to the main switch and the energy storage unit switch. A control method comprising: in the switch control process described above, if it is determined that the main switch or the switch between the energy storage units is experiencing an open fault, an ON command is output to the motor-side switch.

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