Switch control device and program

Abstract

A switching control device (50) suitable for a power supply system comprising: a first power supply (11) and a second power supply (12) connected via an electrical path (13); electric loads (31-33) connected to the electric path and capable of receiving power supply from the first power source and the second power source; and a switch (40) disposed in the electrical path between the connection point of the second power source and the electrical load. A switch control device turns off a switch and diagnoses an on-failure of the switch. The switch control device includes: a determination unit that determines whether or not a first power source is in a power output state in which power is output to an electrical path; and a command unit that temporarily outputs an OFF command to the switch on condition that it is determined that the first power source is in the power output state when the switch is diagnosed.

Description

Citation of related applications

[0001] This application is based on Japanese Patent Application No. 2023-019470 filed on February 10, 2023, and the contents thereof are incorporated herein by reference. Technical Field

[0002] The present disclosure relates to a switch control device and a program for a power supply system. Background Art

[0003] Conventionally, power supply systems are known that include multiple power supplies and electrical loads that can be supplied with power from each power supply. For example, Patent Document 1 describes a technique in which an electrical load is connected to an electrical path connecting the multiple power supplies, a switch is provided between the connection point between one power supply and the electrical load, and a diagnosis is performed to determine whether the switch has a stuck-on fault. Prior art literature Patent Literature

[0004] Patent Document 1: Japanese Patent Application Publication No. 2018-93694 Summary of the Invention

[0005] When diagnosing a switch failure, the switch is sometimes temporarily opened. When the switch is temporarily opened, the supply of driving power to the electrical load via the power supply connected to the switch is temporarily stopped. In this case, the operation of the electrical load may be inadvertently stopped.

[0006] A main object of the present disclosure is to provide a switch control device and a program that can prevent the operation of an electric load from being stopped when diagnosing whether a switch ON failure has occurred.

[0007] The switch control device disclosed herein is applicable to a power supply system, which includes: a first power source and a second power source connected via an electrical path; an electric load connected to the electrical path and capable of receiving power from the first power source and the second power source; and a switch provided in the electrical path between the second power source and the electrical load connection point, wherein the power supply system disconnects the switch and diagnoses a connection failure of the switch; The switch control device comprises: a determination unit configured to determine whether the first power supply is in a power output state in which the first power supply outputs power to the electrical path; and The command unit temporarily outputs an OFF command to the switch when performing the diagnosis, on condition that the first power supply is determined to be in the power output state.

[0008] In the above structure, the switch is opened and the switch connection failure is diagnosed. In this case, when the switch is diagnosed, the power supply from the second power supply to the electric load is temporarily stopped, which may cause the operation of the electric load to stop unintentionally.

[0009] According to the present disclosure, whether the first power supply is in the power output state, outputting power to the electrical path, is determined. When performing switch diagnosis, a disconnect command is temporarily issued to the switch, conditional on the determination that the first power supply is in the power output state. In this manner, power to the electrical load can be ensured during the switch-off period. This prevents unintended power failure of the electrical load and prevents the electrical load from cessation of operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] The above objects, other objects, features and advantages of the present disclosure will become more apparent with reference to the accompanying drawings and the following detailed description. Figure 1 FIG. 1 is an overall configuration diagram of the vehicle-mounted power supply system according to the first embodiment. Figure 2 This is a flowchart showing the processing steps of control executed by the control device. Figure 3 It is a timing chart showing an example of control operations performed by the control device. Figure 4 It is a timing chart showing an example of control operation according to a modification of the first embodiment. Figure 5 It is a timing chart showing an example of control operation according to a modification of the first embodiment. Figure 6 This is a flowchart showing a control processing procedure executed by a control device according to a modification of the first embodiment. Figure 7 FIG. 1 is an overall configuration diagram of an in-vehicle power supply system according to a second embodiment. Figure 8 This is a flowchart showing the processing steps of control executed by the control device. Figure 9 FIG. 1 is an overall configuration diagram of an in-vehicle power supply system according to a third embodiment. DETAILED DESCRIPTION

[0011] <First embodiment> A first embodiment of the switch control device disclosed herein will be described below with reference to the accompanying drawings. In this embodiment, the switch control device is applied to a vehicle-mounted power supply system. The power supply system is installed in an electric vehicle that uses an electric motor as its driving power source.

[0012] like Figure 1As shown, the power supply system includes a first power supply 11 and a second power supply 12, connected by an electrical path 13. The first power supply 11 includes a high-voltage battery 21, a rotating electric machine 22, and a DC-DC converter 23. The high-voltage battery 21 is constructed by connecting a plurality of cells in series. The rated voltage of the high-voltage battery 21 is, for example, several hundred volts. Each cell is a rechargeable and dischargeable battery, specifically a lithium-ion battery.

[0013] The rotating electric machine 22 is the vehicle's driving power source, receiving electricity from the high-voltage battery 21 and transmitting it to the vehicle's drive wheels. Furthermore, the rotating electric machine 22 functions as a generator, performing regenerative power generation while the vehicle is traveling. The rotating electric machine 22 includes an inverter that controls the current in each phase, and the high-voltage battery 21 is connected to the inverter. This allows power to flow between the high-voltage battery 21 and the rotating electric machine 22. The DC-DC converter 23 is connected to the high-voltage battery 21 and steps down the high voltage on the high-voltage battery 21 side. For example, the DC-DC converter 23 steps down the high voltage on the high-voltage battery 21 side to a voltage of 12V to 14V.

[0014] The second power source 12 is composed of a low-voltage battery. The rated voltage of the low-voltage battery is lower than that of the high-voltage battery 21, for example, 12 V. The low-voltage battery is a rechargeable battery, for example, a lead-acid battery or a lithium-ion battery.

[0015] The power supply system includes a first load 31, a second load 32, and a third load 33. Power can be supplied to each of loads 31-33 from the first power supply 11 and the second power supply 12. Each load 31-33 is connected to connection points A, B, and C of the electrical path 13. The positive side of each load 31-33 is connected to the electrical path 13, and the negative side is connected to a grounded location such as the vehicle body.

[0016] The first load 31 to the third load 33 include, for example, various ECUs. The ECU has a built-in memory for storing processed information, and the memory stores information processed during the vehicle's last trip. Therefore, in order to preserve the stored information for a long time, the first load 31 to the third load 33 require the supply of dark current. In addition to the ECU, the first load 31 to the third load 33 may also be an electrical load that requires the supply of dark current in order to maintain at least a part of its function for a long time, specifically, a navigation device, an anti-theft device, a lighting device, etc. In addition, Figure 1 Each of the loads 31 to 33 shown may be a single electric load or a plurality of electric loads.

[0017] Alternatively, each load 31-33 may be another electrical load. For example, each load 31-33 may be an electrical load used for vehicle driving assistance control. Specifically, they may include an electric power steering system that generates assist torque to assist the driver's steering, an electric brake system that applies braking force to the wheels, a camera that monitors the vehicle's surroundings, a laser radar (LIDAR) or other laser radar, a millimeter-wave radar, a two-wire system, or other electrical loads used for vehicle driving assistance control. Specifically, each load 31-33 may be a general electrical load such as an air conditioner, an audio system, power windows, an electric fan for the radiator that cools the engine's cooling water, parking lights, interior lights, a USB power outlet, or a motor that drives the exterior mirrors.

[0018] The power supply system includes a disconnect switch 40 . The disconnect switch 40 is a normally closed switch, such as a relay or a semiconductor switch such as a MOSFET. The disconnect switch 40 is provided in the electrical path 13 between the connection point B of the second load 32 and the connection point C of the third load 33 .

[0019] The power supply system includes a control device 50, a voltage sensor 60 and a current sensor 61 provided on the first power supply 11 side relative to the disconnect switch 40, a voltage sensor 62 and a current sensor 63 provided on the second power supply 12 side relative to the disconnect switch 40, and a switch current sensor 64. Each voltage sensor 60, 62 detects the voltage of the electrical path 13. The current sensor 61 on the first power supply 11 side detects the output current of the first power supply 11. The current sensor 63 on the second power supply 12 side detects the output current of the second power supply 12. The switch current sensor 64 detects the current flowing through the disconnect switch 40. Each current sensor 61, 63, 64 detects current using, for example, a shunt resistor or a Hall element. The control device 50 obtains the detection values ​​of each sensor 60-64.

[0020] The control device 50 is mainly composed of a microcomputer having a CPU and various memories. The functions provided by the control device 50 can be provided by software recorded in a physical memory device and a computer executing the software, software alone, hardware alone, or a combination thereof.

[0021] For example, the control device 50 controls the output voltage of the DCDC converter 23 to keep the terminal voltage or SOC of the low-voltage battery of the second power supply 12 within a specified range. When charging the low-voltage battery, the control device 50 controls the output voltage of the DCDC converter 23 to be higher than the rated voltage of the low-voltage battery. When discharging the low-voltage battery, the control device 50 controls the output voltage of the DCDC converter 23 to be lower than the rated voltage of the low-voltage battery. For example, the control device 50 determines the terminal voltage or SOC of the low-voltage battery of the second power supply 12 based on the detection values ​​of the sensors 62 and 63 on the second power supply 12 side.

[0022] For example, the control device 50 determines whether an overcurrent anomaly, in which excessive current is flowing, has occurred in the electrical path 13 based on the current flowing through the disconnect switch 40. If an overcurrent anomaly is determined to have occurred, the control device 50 opens the disconnect switch 40. This prevents excessive current from flowing in the electrical path 13. The overcurrent anomaly may be caused by a ground fault, in which a portion of the electrical path 13 is short-circuited to a ground point, or by a loss of control of the electrical load. For example, the control device 50 uses the detection value of the switch current sensor 64 as the current flowing through the disconnect switch 40.

[0023] The control device 50 includes a diagnostic unit 51. The diagnostic unit 51 opens the disconnect switch 40 and diagnoses whether a closed fault has occurred, in which the switch is stuck in the closed state. For example, the diagnostic unit 51 diagnoses the disconnect switch 40 based on the detection value of the switch current sensor 64 and the detection value of the voltage sensor 62 on the second power supply 12 side.

[0024] Furthermore, if the disconnect switch 40 is temporarily opened during diagnosis, the supply of drive power from the second power supply 12 to the first and second loads 31, 32 is temporarily stopped. In this case, for example, if the DC-DC converter 23 stops outputting power, the power supply from the first power supply 11 to the first and second loads 31, 32 may become insufficient, causing the operation of the first and second loads 31, 32 to stop unintentionally.

[0025] Therefore, the control device 50 includes a determination unit 52 and an instruction unit 53. The determination unit 52 determines whether the first power source 11 is in the power output state to the electrical path 13. When performing a diagnosis of the disconnect switch 40, the instruction unit 53 temporarily outputs an off instruction to the disconnect switch 40, provided that the first power source 11 is determined to be in the power output state.

[0026] Figure 2 1 shows a process sequence of control executed by the control device 50. This control is executed when a start switch is turned on as a trigger. The start switch is, for example, an ignition switch or a push-type start switch, and is operated by a vehicle user.

[0027] Here, it is assumed that immediately after the start switch is turned on, the operation of the DCDC converter 23 stops, and the driving power of the loads 31 to 33 is supplied from the second power supply 12 .

[0028] In step S10, the path voltage of the electrical path 13 is acquired. The acquired path voltage is then stored in the memory of the control device 50. In this case, since the operation of the DC-DC converter 23 stops immediately after the start switch is turned on, the path voltage of the electrical path 13 becomes a value corresponding to the output voltage of the second power supply 12.

[0029] In step S11, a power output command of the DCDC converter 23 is output so that the output voltage of the DCDC converter 23 becomes higher than the output voltage of the second power supply 12. Specifically, the power output command of the DCDC converter 23 is a drive command of a switch included in the DCDC converter 23.

[0030] In step S12, the path voltage of the electrical path 13 after the power output command is output is acquired. In this case, the path voltage of the electrical path 13 becomes a value corresponding to the output voltage of the DC-DC converter 23. In the processing of steps S10 and S12, at least one of the detection value of the voltage sensor 60 on the first power supply 11 side and the detection value of the voltage sensor 62 on the second power supply 12 side can be used as the path voltage of the electrical path 13.

[0031] In step S13, it is determined whether the first power supply 11 is in the power output state. In this embodiment, it is determined whether the path voltage of the electrical path 13 has increased after the power output instruction is output. Specifically, it is determined whether the voltage increase value obtained by subtracting the path voltage obtained in the process of step S10 (i.e., the voltage stored in the memory) from the path voltage obtained in the process of step S12 is higher than a predetermined threshold. The threshold value is a value higher than 0V. If a positive determination is made in step S13, the process proceeds to step S14. If a negative determination is made in step S13, the process proceeds to step S18.

[0032] In step S14 , an OFF command is outputted to open the disconnect switch 40 for a predetermined period.

[0033] In step S15, while the disconnect switch 40 is being commanded to open, the path voltage on the second power supply 12 side of the electrical path 13 is acquired. The path voltage on the second power supply 12 side of the electrical path 13 can be the value detected by the voltage sensor 62 on the second power supply 12 side. The diagnostic unit 51 executes the process of step S15 while the disconnect switch 40 is being commanded to open.

[0034] In step S16, the presence or absence of an ON fault in the disconnect switch 40 is determined based on the path voltage on the second power supply 12 side of the electrical path 13. If it is determined in step S16 that there is no ON fault in the disconnect switch 40, the process proceeds to step S17. On the other hand, if it is determined in step S16 that there is an ON fault in the disconnect switch 40, the process proceeds to step S18.

[0035] For example, if a disconnect switch 40 failure has not occurred, then when an OFF command is issued for disconnect switch 40, disconnect switch 40 actually opens, and the path voltage on the second power supply 12 side of electrical path 13 returns to the value before the power output command was issued. Therefore, if the absolute value of the difference between the path voltage acquired in step S15 and the path voltage acquired in step S10 is below a predetermined threshold, it is determined that a disconnect switch 40 failure has not occurred. On the other hand, if a disconnect switch 40 failure has occurred, then even if an OFF command is issued for disconnect switch 40, disconnect switch 40 does not actually open, and the path voltage on the second power supply 12 side of electrical path 13 remains at the value after the power output command was issued. Therefore, if the absolute value of the path voltage difference exceeds a threshold, the diagnostic unit 51 determines that a disconnect switch 40 failure has occurred. The threshold is, for example, a positive value near zero.

[0036] The method for determining whether disconnect switch 40 has a connection fault is not limited to the method described above. For example, the current flowing through disconnect switch 40 may be acquired, and the presence of a connection fault in disconnect switch 40 may be determined based on this acquired value. In this case, if the current flowing through disconnect switch 40 in the off state is less than a determination value, it is determined that there is no connection fault in disconnect switch 40. On the other hand, if the current flowing through disconnect switch 40 in the off state is greater than or equal to a determination value, it is determined that there is a connection fault in disconnect switch 40. Here, the determination value is, for example, a value greater than 0. Alternatively, the detection value of switch current sensor 64 may be used as the current flowing through disconnect switch 40.

[0037] In steps S17 and S18, a flag is set. For example, the flag is transmitted to a higher-level control device relative to the control device 50 and is used to determine whether the automatic operation mode can be switched to. Specifically, if the flag is off, the automatic operation mode is allowed, while if the flag is on, the automatic operation mode is prohibited. In step S17, the flag is set to off. On the other hand, in step S18, the flag is set to on.

[0038] Furthermore, when the flag is on, the host control device may perform processing to notify the user that an on-failure of the disconnect switch 40 has occurred.

[0039] Figure 3 An example of control executed by the control device 50 is shown. Figure 3 The operation example shown is an operation example when the disconnect switch 40 does not have an ON failure. Figure 3 In FIG. 1 , (a) shows the change of the voltage V2 on the second power supply 12 side closer to the disconnect switch 40 in the electrical path 13, (b) shows the change of the voltage V1 on the first power supply 11 side closer to the disconnect switch 40 in the electrical path 13, and (c) shows the on and off of the disconnect switch 40. Figure 3 In FIG, it is assumed that no power output of the first power source 11 is generated before time t1.

[0040] At time t1, the control device 50 acquires the path voltage of the electrical path 13 and stores the acquired voltage value Va in memory. At time t2, the control device 50 outputs a power output command to the DC-DC converter 23. As a result, the voltage V1 on the first power supply 11 side and the voltage V2 on the second power supply 12 side increase.

[0041] At time t3, the control device 50 acquires the path voltage of the electrical path 13 after the power output command is issued. It determines that the voltage increase value, obtained by subtracting the voltage value Va stored in memory from the acquired voltage value, exceeds the threshold value. Accordingly, the control device 50 issues an off command for the disconnect switch 40. As a result, the disconnect switch 40 is opened, and the voltage V2 on the second power supply 12 side returns to the value before the power output command was issued. While the off command for the disconnect switch 40 is being issued, the control device 50 acquires the detection value of the voltage sensor 62 on the second power supply 12 side. Based on the acquired detection value of the voltage sensor 62 on the second power supply 12 side, the control device 50 determines whether the disconnect switch 40 has an on-state fault and sets a fault flag based on the determination result.

[0042] According to the present embodiment described in detail above, the following effects can be obtained.

[0043] The system determines whether the first power source 11 is in the power output state, outputting power to the electrical path 13. When performing a diagnosis of the disconnect switch 40, a disconnect command is temporarily output to the disconnect switch 40, conditional on the determination that the first power source 11 is in the power output state. In this manner, the driving power for the first and second loads 31, 32 can be ensured while the disconnect switch 40 is off. This prevents unintended power failures to the first and second loads 31, 32, and prevents the operation of the first and second loads 31, 32 from being interrupted.

[0044] Whether the first power supply 11 is in the power output state is determined based on the path voltage of the electrical path 13. Specifically, if the path voltage of the electrical path 13 rises after the power output command is issued, the first power supply 11 is determined to be in the power output state. This ensures that the first power supply 11 is in the power output state.

[0045] <Modification of the First Embodiment> In the previous Figure 2 In the process of step S13, the method for determining whether the first power supply 11 is in the power output state may be changed. Here, the determination method using the output current of the first power supply 11 will be described.

[0046] In step S13, the output current of the first power supply 11 is acquired. If it is determined that the output current of the first power supply 11 exceeds a predetermined threshold current Ith1, it is determined that the first power supply 11 is in the power output state. The output current of the first power supply 11 can be the detection value of the current sensor 61 on the first power supply 11 side. On the other hand, if it is determined that the output current of the first power supply 11 is less than the threshold current Ith1, it is determined that the first power supply 11 is not in the power output state. For example, the threshold current Ith1 is a value greater than 0.

[0047] Figure 4 An example of control operations performed by the control device 50 of this embodiment is shown. Figure 4 (b) shows the transition of the output current I1 of the first power supply 11 . Figure 4 (a) and (c) correspond to the previous Figure 3 (b) and (c).

[0048] At time t1, the control device 50 outputs a power output command to the DC-DC converter 23. This causes the voltage V1 on the first power supply 11 side of the disconnect switch 40 in the electrical path 13 and the output current I1 of the first power supply 11 to increase. At time t2, the control device 50 determines that the output current of the first power supply 11 exceeds the threshold current Ith1. In response, the control device 50 outputs an opening command to the disconnect switch 40. As a result, the disconnect switch 40 opens.

[0049] The current flowing through the second power source 12 may also be used to perform diagnosis of the disconnect switch 40 .

[0050] In step S13, the current flowing through the second power supply 12 is obtained. Here, the current flowing in the direction in which the low-voltage battery of the second power supply 12 is charged is set to positive, and the current flowing in the direction in which the low-voltage battery of the second power supply 12 is discharged is set to negative, and the current flowing through the second power supply 12 is obtained. When it is determined that the current flowing through the second power supply 12 exceeds the prescribed threshold current Ith2, it is determined that the first power supply 11 is in the power output state. The threshold current Ith2 is set to a value greater than 0, for example. That is, the threshold current Ith2 is set to a value that can determine that the current flows from the first power supply 11 to the second power supply 12 and flows through the electrical path 13. As the current flowing through the second power supply 12, the detection value of the current sensor 63 on the second power supply 12 side is used.

[0051] Figure 5 An example of control operations performed by the control device 50 of this embodiment is shown. Figure 5 (b) shows the transition of the current I2 flowing through the second power supply 12. Figure 5 (a) and (c) correspond to the previous Figure 4 (a) and (c) of the preceding text.

[0052] At time t1, the control device 50 outputs a power output command to the DC-DC converter 23. This causes the voltage V1 on the first power source 11 side of the disconnect switch 40 in the electrical path 13 and the current I2 flowing through the second power source 12 to increase. At time t2, the control device 50 determines that the current flowing through the second power source 12 exceeds the threshold current Ith2. In response, the control device 50 outputs an opening command to the disconnect switch 40. Consequently, the disconnect switch 40 opens.

[0053] According to this embodiment, the detection value of the current sensor 63 on the second power supply 12 side is used to determine whether the first power supply 11 is in the power output state. The detection value of the current sensor 63 on the second power supply 12 side is also used, for example, to determine the state of charge (SOC) of the low-voltage battery included in the second power supply 12. In this case, the number of sensors provided in the power supply system can be reduced while still enabling diagnosis of the disconnect switch 40.

[0054] The current flowing through the disconnect switch 40 may be used to perform the diagnosis of the disconnect switch 40. In this case, in step S13, the same process as the diagnosis of the disconnect switch 40 using the current flowing through the second power supply 12 is performed. As the current flowing through the disconnect switch 40, the detection value of the switch current sensor 64 can be used. Figure 5 (b) is considered to show the change of the current flowing through the disconnect switch 40, and the control operation example performed by the control device 50 of this embodiment is the same as that of Figure 5 same.

[0055] According to this embodiment, the detection value of the switching current sensor 64 is used to determine whether the first power supply 11 is in the power output state. The detection value of the switching current sensor 64 is also used to detect an overcurrent abnormality, for example. In this case, the number of sensors provided in the power supply system can be reduced while performing a diagnosis of the disconnect switch 40.

[0056] In the previous Figure 2 In step S13, if the path voltage of electrical path 13 exceeds a predetermined threshold voltage, it may be determined that first power supply 11 is in the power output state. In this case, step S10 may not be performed. Alternatively, the threshold voltage may be, for example, a value higher than the rated voltage of the low-voltage battery included in second power supply 12.

[0057] In the previous Figure 2 In the processing of step S13, at least two of the path voltage of the electrical path 13, the output current of the first power supply 11, the current flowing through the second power supply 12, and the current flowing through the disconnect switch 40 can also be used to determine whether the first power supply 11 is in the power output state.

[0058] In the previous Figure 2 In the process of step S13, if it is determined that the power output command of the DCDC converter 23 is output, it may be determined that the first power supply 11 is in the power output state. In this case, the processes of steps S10 and S12 may not be performed.

[0059] In this embodiment, the control device 50 executes Figure 6 The control shown in FIG. Instead of executing this control when the start switch is turned on, this control is executed every predetermined period. Here, it is assumed that the vehicle is running and the diagnosis of the cutoff switch 40 is performed during the operation of the DCDC converter 23. Figure 6 For convenience, the previous Figure 2 The same processes are denoted by the same step numbers.

[0060] In this embodiment, instead of executing the previous Figure 2 The processing of steps S10 to S12 is as follows: Figure 6 As shown, the process of step S20 is executed. In step S20, the power output of first power supply 11 is adjusted based on the power requirements of first load 31 and second load 32 connected to the side of first power supply 11 closer to disconnect switch 40 in electrical path 13. Specifically, the higher the power requirements of first load 31 and second load 32, the higher the set value of the output voltage of DCDC converter 23. The process of step S20 corresponds to the "power adjustment unit."

[0061] In step S13 , determination of whether the first power source 11 is in the power output state is performed using at least one of the output current of the first power source 11 , the current flowing through the second power source 12 , and the current flowing through the disconnect switch 40 . According to this embodiment, the output voltage setting value of the DCDC converter 23 is set higher as the power demanded by the first and second loads 31, 32 increases. Consequently, even if the power demanded by the first and second loads 31, 32 increases, driving power can be supplied from the first power supply 11 to the first and second loads 31, 32. Therefore, during the diagnosis of the disconnect switch 40, insufficient driving power from the first power supply 11 to the first and second loads 31, 32 can be reliably prevented.

[0062] In the previous Figure 2 In the process of step S13, the determination condition for determining whether the first power source 11 is in the power output state may be changed.

[0063] Considering that the power demand of at least one of the first load 31 and the second load 32 may change on the side of the first power source 11 closer to the disconnect switch 40 in the electrical path 13, it is desirable to anticipate the change in power demand and predetermine the conditions for determining whether power supply from the first power source 11 to the first load 31 and the second load 32 is appropriate in order to ensure the operation of the first load 31 and the second load 32. Furthermore, if the conditions are too narrow, the opportunity to diagnose the disconnect switch 40 may be unnecessarily reduced.

[0064] Therefore, the determination unit 52 changes the determination condition of whether the first power supply 11 is in the power output state according to the required power of the first load 31 and the second load 32 connected to the first power supply 11 side of the disconnect switch 40 in the electrical path 13 .

[0065] Specifically, in the previous Figure 2 In step S13, if at least one of the power requirements of the first load 31 and the power requirements of the second load 32 is higher, the determination condition is changed to the one that results in a higher output power from the first power source 11. For example, when determining the power output state using the voltage increase values ​​before and after the power output command is issued to the DC-DC converter 23, the higher the total power requirements of the loads 31 and 32, the higher the threshold value used for determination. According to this embodiment, the determination condition of whether the first power supply 11 is in the power output state is changed according to at least one of the power requirements of the loads 31 and 32. This allows for appropriate fault diagnosis even when the power requirements of the loads 31 and 32 are assumed to change.

[0066] A configuration in which the third load 33 is not provided in the electrical path 13 can be adopted.

[0067] <Second embodiment> In the present embodiment, when the diagnosis of the disconnect switch 40 is performed, the energization of the second load 32 is restricted.

[0068] In this embodiment, the first load 31 is prioritized over the second load 32 in continuous operation during the diagnosis of the disconnect switch 40. For example, the first load 31 is an electrical load that requires at least some functions of an ECU, etc. to continue for a long period of time, while the second load 32 is a general electrical load. In this case, the operation of the second load 32 during the diagnosis of the disconnect switch 40 may cause insufficient power to the first load 31. To address this issue, in this embodiment, power to the second load 32 is limited during the diagnosis of the disconnect switch 40.

[0069] like Figure 7 As shown, the power supply system includes a load switch 41. The load switch 41 is a normally closed switch, for example, a semiconductor switch such as a relay or a MOSFET. The load switch 41 is provided in an electrical path connecting the connection point B of the second load 32 and the positive side of the second load 32. The control device 50 limits the power supply to the second load 32 by turning off the load switch 41 before outputting the off command of the switch 40. In addition, Figure 7 For convenience, the previous Figure 1 The same symbols are given to duplicate structures, and some are not shown in the figure.

[0070] The power supply system includes a load current sensor 65 that detects the current flowing through the load switch 41. The load current sensor 65 detects the current using, for example, a shunt resistor or a Hall element.

[0071] If restriction of power supply to the second load 32 is not possible, the command unit 53 does not output an opening command to disconnect the switch 40. For example, the command unit 53 obtains the current flowing through the load switch 41 in the off state. If the obtained current value is greater than a predetermined value, the command unit 53 determines that restriction of power supply to the second load 32 is not possible and does not output an opening command to disconnect the switch 40. The current flowing through the load switch 41 can be measured by the detection value of the load current sensor 65. Alternatively, a situation in which restriction of power supply to the second load 32 is not possible could be a situation in which the load switch 41 has an ON fault.

[0072] like Figure 8As shown, in step S30, it is determined whether the restriction on the power supply to the second load 32 is not possible. In the case of a negative determination in step S30, the process proceeds to step S31. In step S31, when the diagnosis of the disconnect switch 40 is implemented, the power supply to the second load 32 is restricted by disconnecting the load switch 41 before outputting the disconnect instruction of the disconnect switch 40. On the other hand, in the case of an affirmative determination in step S30, the process proceeds to step S18. That is, in the case where it is determined that the restriction on the power supply to the second load 32 is not possible, the output of the disconnect instruction of the disconnect switch 40 is not performed. In addition, the processing of step S31 is equivalent to the "power supply restriction unit". In Figure 8 For convenience, the previous Figure 2 The same processes are denoted by the same step numbers.

[0073] During the actual diagnosis of the disconnect switch 40, by limiting the energization of the second load 32, during the period when the disconnect switch 40 is off, the supply of driving power to the first load 31 is prioritized over the supply of driving power from the first power supply 11 to the second load 32. As a result, insufficient supply of driving power to the first load 31 can be reliably prevented.

[0074] When performing a diagnosis of the disconnect switch 40, if it is determined that the restriction on the energization of the second load 32 is not possible, the disconnect switch 40 opening command is not output. This allows the disconnect switch 40 to be omitted from the diagnosis when there is a possibility that the driving power supplied to the first load 31 may be insufficient.

[0075] <Modification of Second Embodiment> In the previous Figure 8 In step S31 , instead of opening the load switch 41 , the energization to the second load 32 may be limited by stopping the operation of the second load 32 or reducing the power required by the second load 32 .

[0076] In the previous Figure 8 In step S31, power supply to the second load 32 is restricted based on the power requirements of the loads 31 and 32 connected to the first power source 11 side of the disconnect switch 40 in the electrical path 13. For example, if the total power requirements of the loads 31 and 32 are equal to or greater than a predetermined power level, power supply to the second load 32 is restricted. If the total power requirements are lower than the predetermined power level, power supply to the second load 32 is not restricted. This embodiment can prevent unnecessary restriction of the function of the second load 32 in situations where the likelihood of insufficient power supply to the first load 31 is low.

[0077] · You can also not do the previous Figure 8 The process of step S30.

[0078] <Third embodiment> In this embodiment, the structure of the power supply system is changed compared to the first embodiment. Figure 9 As shown, disconnect switches 40 are provided at a plurality of locations between the connection points of the loads 31 to 33 in the electrical path 13. at a position in the electrical path 13 between the connection points A, B of the respective loads 31, 32; and At a position in the electrical path 13 between the connection points B and C of the loads 32 and 33, A cut-off switch 40 is provided respectively. Figure 9 In the embodiment, the disconnect switch 40 provided between the connection points A and B in the electrical path 13 is referred to as the “disconnect switch 40a”, and the disconnect switch 40 provided between the connection points B and C in the electrical path 13 is referred to as the “disconnect switch 40b”. Figure 9 For convenience, the previous Figure 1 The same symbols are given to duplicate structures, and some are not shown in the figure.

[0079] The command unit 53 temporarily outputs a disconnect command to the multiple disconnect switches 40a and 40b provided in the electrical path 13. In this embodiment, while performing a diagnosis on each of the disconnect switches 40a and 40b, the command unit 53 sets each of the disconnect switches 40a and 40b provided in the electrical path 13 as a disconnect target and outputs a disconnect command. For example, the command unit 53 sets the disconnect switch 40a as a disconnect target and outputs a disconnect command. After performing a diagnosis on the disconnect switch 40a, the command unit 53 sets the disconnect switch 40b as a disconnect target and outputs a disconnect command.

[0080] In the above configuration, the first load 31 is connected to the first power supply 11 side relative to the disconnect switch 40a of the electrical path 13, and the first load 31 and the second load 32 are connected to the first power supply 11 side relative to the disconnect switch 40b of the electrical path 13. In this case, when the disconnect switch 40b is opened, the number of electrical loads connected to the first power supply 11 side in the electrical path 13 is greater than when the disconnect switch 40a is opened, and the possibility of insufficient drive power from the first power supply 11 to the first load 31 and the second load 32 is considered to be higher.

[0081] Therefore, the determination unit 52 changes the determination condition of whether the first power supply 11 is in the power output state according to the number of electric loads connected to the first power supply 11 side of the disconnector 40 to be disconnected by the instruction unit 53 in the electric path 13.

[0082] Specifically, when disconnect switch 40b is set to be disconnected, determination unit 52 changes the determination condition to one where the output power of first power source 11 is higher than when disconnect switch 40a is set to be disconnected. For example, when determination unit 52 uses the voltage rise value before and after the power output command of DCDC converter 23 to determine the power output state, the greater the number of electrical loads in electrical path 13 connected to the first power source 11 side relative to disconnect switch 40, which is the target of disconnection, the higher the threshold used for determination.

[0083] According to this embodiment, the criteria for determining whether first power supply 11 is in the power output state are changed based on the number of electrical loads connected to the side of first power supply 11 relative to disconnect switches 40a, 40b in electrical path 13. This allows for appropriate fault diagnosis, taking into account changes in the number of electrical loads and the power requirements of the loads.

[0084] <Other implementation methods> In addition, each of the above-mentioned embodiments may be implemented with the following modifications.

[0085] The structure of the first power source 11 may be changed. For example, the first power source 11 may be a rechargeable and dischargeable battery.

[0086] The disconnect switch 40 and the load switch 41 do not have to be normally closed switches.

[0087] The power supply system may be a system other than the vehicle, or may be installed on a mobile object other than the vehicle. Furthermore, the power supply system may be stationary.

[0088] The control unit and method thereof described in the present disclosure may also be implemented by a special-purpose computer, which is provided by constituting a processor and a memory, and the processor is programmed to execute one or more functions embodied by a computer program. Alternatively, the control unit and method thereof described in the present disclosure may be implemented by a special-purpose computer, which is provided by constituting a processor by one or more special-purpose hardware logic circuits. Alternatively, the control unit and method thereof described in the present disclosure may be implemented by one or more special-purpose computers, which are constituted by a combination of a processor and a memory programmed to execute one or more functions and a processor constituted by one or more hardware logic circuits. In addition, the computer program may also be stored in a computer-readable non-temporary tangible recording medium as an instruction executed by a computer.

[0089] The following describes technical ideas extracted from the above-mentioned embodiments. [Structure 1] A switch control device, the switch control device (50) is suitable for a power supply system, the power supply system comprising: A first power source (11) and a second power source (12) connected via an electrical path (13); and electrical loads (31 to 33) connected to the electrical path and capable of receiving power from the first power source and the second power source. A switch (40) is provided in the electrical path between a connection point between the second power source and the electrical load, the power supply system disconnecting the switch and diagnosing a connection failure of the switch. The switch control device comprises: a determination unit configured to determine whether the first power supply is in a power output state in which the first power supply outputs power to the electrical path; and The command unit temporarily outputs an OFF command to the switch on condition that the first power supply is determined to be in the power output state when performing the diagnosis. [Structure 2] The switch control device as described in Structure 1, wherein: The determination unit determines whether the first power supply is in the power output state based on at least one of a path voltage of the electrical path, an output current of the first power supply, and a direction of a current flowing through the electrical path. [Structure 3] The switch control device as described in structure 1 or 2, wherein: The determination unit changes a determination condition of whether the first power supply is in the power output state according to a power requirement of the electric load connected to the electrical path closer to the first power supply than the switch. [Structure 4] The switch control device as described in any one of Structures 1 to 3, wherein: The plurality of electric loads are connected to the electric path, and the switches (40a, 40b) are provided at a plurality of locations between the connection points of the electric loads. When performing the diagnosis, the command unit sets the plurality of switches provided in the electrical path as disconnection targets one by one and outputs disconnection commands. The determination unit changes a determination condition of whether the first power supply is in the power output state according to the number of the electrical loads connected to the electrical path closer to the first power supply than the switch to be disconnected by the instruction unit. [Structure 5] A switch control device as described in any one of Structures 1 to 4, wherein: The invention further includes a energization restriction unit that restricts energization of the electric load connected to the first power supply side of the switch in the electrical path before the instruction unit outputs an instruction to turn off the switch when the diagnosis is performed. [Structure 6] The switch control device as described in Structure 5, wherein: The energization limiting unit limits energization to the electric load connected to the electric path closer to the first power supply than the switch, based on a power demand of the electric load. [Structure 7] The switch control device as described in structure 5 or 6, wherein: The command unit does not output an OFF command for the switch when the energization restriction unit has disabled restriction of energization. [Structure 8] A switch control device as described in any one of Structures 1 to 7, wherein: The first power supply is configured to be able to adjust the magnitude of the power output to the electrical path. A power regulator is included, which changes the magnitude of the power output of the first power supply according to the power required by the electric load connected to the electrical path closer to the first power supply than the switch when the diagnosis is performed.

[0090] Although the present disclosure is described based on embodiments, it should be understood that the present disclosure is not limited to the above-described embodiments and structures. The present disclosure also includes various modifications and variations within the scope of equivalents. In addition, various combinations and methods, and further combinations and methods that include only one element, or more or less than the above elements, also fall within the scope and concept of the present disclosure.

Claims

1. A switch control device, the switch control device (50) being suitable for a power supply system, the power supply system comprising: a first power source (11) and a second power source (12) connected via an electrical path (13); an electric load (31-33) connected to the electric path and capable of receiving power from the first power source and the second power source; as well as a switch (40) provided in the electrical path between a connection point between the second power source and the electrical load, The power supply system turns off the switch and diagnoses a turn-on failure of the switch, The switch control device comprises: a determination unit that determines whether the first power supply is in a power output state of outputting power to the electrical path; as well as The command unit temporarily outputs an OFF command to the switch on condition that the first power source is determined to be in the power output state when the diagnosis is performed.

2. The switch control device according to claim 1, wherein: The determination unit determines whether the first power supply is in the power output state based on at least one of a path voltage of the electrical path, an output current of the first power supply, and a direction of a current flowing through the electrical path.

3. The switch control device according to claim 1, wherein: The determination unit changes a determination condition of whether the first power supply is in the power output state, based on a power requirement of the electric load connected to the electrical path closer to the first power supply than the switch.

4. The switch control device according to claim 1, wherein: A plurality of the electric loads are connected to the electric path, and the switches (40a, 40b) are provided at a plurality of positions between the connection points of the electric loads. When performing the diagnosis, the command unit sets the plurality of switches provided in the electrical path as disconnection targets one by one and outputs disconnection commands. The determination unit changes a determination condition of whether the first power supply is in the power output state according to the number of the electric loads connected to the first power supply side of the switch to be disconnected by the instruction unit in the electrical path.

5. The switch control device according to any one of claims 1 to 4, characterized in that: A energization restriction unit is included for restricting energization of the electric load connected to the first power supply side of the switch in the electrical path before the instruction unit outputs an instruction to turn off the switch when the diagnosis is performed.

6. The switch control device according to claim 5, wherein: The energization limiting unit limits energization to the electric load connected to the electric path closer to the first power supply than the switch, based on power demand of the electric load.

7. The switch control device according to claim 5, wherein: The command unit does not output an OFF command for the switch when the energization restriction unit prohibits energization.

8. The switch control device according to any one of claims 1 to 4, characterized in that: The first power supply is configured to be able to adjust the magnitude of the power output to the electrical path. A power regulator is provided for changing the magnitude of power output of the first power supply according to power demand of the electric load connected to the electrical path closer to the first power supply than the switch when the diagnosis is performed.

9. A program adapted for use in a power supply system and executed by a computer (50), The power supply system comprises: a first power source (11) and a second power source (12) connected via an electrical path (13); an electric load (31, 33) connected to the electrical path and capable of receiving power from the first power source and the second power source; as well as a switch (40) provided in the electrical path between a connection point between the second power source and the electrical load, The power supply system turns off the switch and diagnoses a turn-on failure of the switch, The program causes the computer to execute a process including the following steps: a determining step of determining whether the first power supply is in a power output state of outputting power to the electrical path; as well as and an instruction step of temporarily outputting an off instruction to the switch on the condition that it is determined that the first power supply is in the power output state when the diagnosis is performed.

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