Power supply control device and power supply control program

Abstract

To provide a power supply control device and a power supply control program, capable of suppressing the generation of an in-rush current.SOLUTION: A power supply control device is a power supply control device controlling supply of power to a load of a vehicle via a first power supply switch from a first power supply and supply of power to a load via a second power supply switch from a second power supply, and includes a controller. The controller supplies power to a first load from the second power supply by turning on the second power supply switch in the case where an IG of the vehicle is in OFF. In the case where the IG is turned ON, power is supplied to a second load from the first power supply by turning on the first power supply switch. The controller turns on the first power supply switch after a voltage of the first power supply is reduced to a voltage of the second power supply in the case where the voltage of the first power supply is higher than the voltage of the second power supply by a threshold value or more, and the power is supplied from the first power supply only to the second load, among the second loads, having a high predetermined priority.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a power supply control device and a power supply control program. [Background technology]

[0002] Conventionally, a system is known in which power is supplied from a second power source to some loads while the vehicle is parked with the ignition (hereinafter, IG) turned off, and power is supplied from a first power source to all loads including the remaining loads when the IG is turned on (for example, see Patent Document 1). In this type of system, the voltage of the second power source continues to drop due to power supply while the vehicle is parked, so when the IG is turned on and power supply begins from the first power source, if the voltage difference between the first power source and the second power source is large, an inrush current occurs in the circuit.

[0003] In relation to this, a technique has been disclosed for suppressing inrush current by temporarily lowering the voltage of a first power supply when the IG is turned on to reduce the voltage difference with the second power supply (see, for example, Patent Document 2). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2023-071507 [Patent Document 2] JP 2015-123825 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the conventional technology, when there are a large number of loads that start supplying power immediately after the IG is turned on, the total sum of the currents output from the first power source to each load becomes large, which may result in an inrush current.

[0006] The present application has been made in consideration of the above, and has an object to provide a power supply control device and a power supply control program capable of suppressing the occurrence of inrush current. [Means for solving the problem]

[0007] A power supply control device according to the present application is a power supply control device that controls power supply from a first power source to a load of a vehicle via a first power source switch and power supply from a second power source to the load via a second power source switch, and includes a controller. When an IG of the vehicle is off, the controller turns on the second power source switch to supply power from the second power source to the first load, and when the IG is on, turns on the first power source switch to supply power from the first power source to the second load. When the IG is on and the voltage of the first power source is higher than the voltage of the second power source by a threshold or more, the controller reduces the voltage of the first power source to the voltage of the second power source before turning on the first power source switch, and supplies power from the first power source only to the second load that has a higher predetermined priority among the second loads. Effect of the Invention

[0008] In the present disclosure, after the IG is turned on, power is supplied only to the loads with high priority, and power is not supplied to the loads with low priority. This reduces the number of loads to which power is supplied after the IG is turned on, and the total sum of the currents output from the first power source to each load is reduced, thereby suppressing the occurrence of inrush current. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is an explanatory diagram illustrating an example of the configuration of a power supply control system according to an embodiment. [Diagram 2] FIG. 2 is an explanatory diagram illustrating an example of the configuration of a power supply control system according to the embodiment. [Diagram 3] FIG. 3 is an explanatory diagram illustrating an example of the configuration of a power supply control system according to the embodiment. [Figure 4] FIG. 4 is an explanatory diagram illustrating an example of the configuration of a power supply control system according to the embodiment. [Diagram 5] FIG. 5 is an explanatory diagram illustrating an example of the configuration of a power supply control system according to the embodiment. [Figure 6] FIG. 6 is a timing chart showing the operation of the power supply control system. [Figure 7] FIG. 7 is a flowchart showing the procedure of the power supply process executed by the power supply control device according to the embodiment. [Figure 8] FIG. 8 is a diagram illustrating an example of the configuration of a power supply control device according to a modified example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, an embodiment of a power supply control device and a power supply control program will be described in detail with reference to the accompanying drawings. Note that the present invention is not limited to the following embodiment.

[0011] [Example of configuration of power supply control system according to embodiment] 1 to 5 are explanatory diagrams showing an example of the configuration of a power supply control system S according to an embodiment. As shown in FIG. 1, the power supply control system S includes a power supply control device 1, a first power supply 10, a second power supply 20, first to fourth loads 41 to 44, and first to seventh sensors 51 to 57. In the power supply control system S, the first power supply 10, the second power supply 20, the first to fourth loads 41 to 44, and the first to seventh sensors 51 to 57 are connected to the power supply control device 1. Here, a case will be described in which four loads are connected to the power supply control device 1, but the number of loads connected to the power supply control device 1 is not limited to four as long as it is two or more.

[0012] The first power source 10 is, for example, a main battery mounted on a vehicle. The first power source 10 includes a first battery 101 and a DCDC 102. The first battery 101 is, for example, a lead battery. The first battery 101 may be a secondary battery other than a lead battery. The DCDC 102 is a converter that steps down the voltage (output voltage) of the first battery 101.

[0013] The second power source 20 is a backup power source that supplies power in place of the first power source 10 when the first power source 10 is unable to supply power. The second power source 20 includes a second battery 201. The second battery 201 is, for example, a lithium ion battery. The second battery 201 may be a secondary battery other than a lithium ion battery. In this embodiment, the voltage (output voltage) of the first power source 10 is described as being slightly higher (for example, a voltage difference of about 0.5 to 1 V) than the voltage (output voltage) of the second power source 20.

[0014] The first to fourth loads 41 to 44 include various electronic devices mounted on a vehicle, such as an engine control device, a steering control device, a brake control device, an audio device, a video display device, and various sensors.

[0015] Among the first to fourth loads 41 to 44, the first load 41 consumes more power immediately after startup than the second to fourth loads 42 to 44. In other words, the first load 41 consumes power equal to or greater than a threshold, and the second to fourth loads 42 to 44 consume less than a threshold. For example, the first load 41 is a device such as a brake or steering. The fourth load 44 operates when the IG is off and when the IG is on. For example, the fourth load 44 is a device such as a drive recorder, security, or a device that communicates with the outside. In the embodiment, the first load is a load that operates when the IG is off, and the fourth load 44 corresponds to this. The second load is a load that operates when the IG is on, and the first to fourth loads 41 to 44 correspond to this.

[0016] The first power source 10 is electrically connected to the power supply control device 1 via a first power supply line L1. The second power source 20 is electrically connected to the power supply control device 1 via a second power supply line L2. The first to fourth loads 41 to 44 are electrically connected to the power supply control device 1 via a load power supply line L3.

[0017] The power supply control device 1 is a device that outputs and supplies power input from the first power supply 10 or the second power supply 20 to the first to fourth loads 41 to 44. The power supply control device 1 includes a common power supply line L4, first to sixth switches 11 to 16, and a controller 3. The common power supply line L4 is a power supply line that electrically connects the first power supply line L1, the second power supply line L2, and the load power supply line L3.

[0018] The first switch 11 is a switch that connects the first power feed line L1 and the common power feed line L4. When the first switch 11 is turned on, the first power feed line L1 and the common power feed line L4 are electrically connected. When the first switch 11 is turned off, the first switch 11 cuts off the electrical connection between the first power feed line L1 and the common power feed line L4.

[0019] The second switch 12 is a switch that connects the second power feed line L2 and the common power feed line L4. When the second switch 12 is turned on, the second power feed line L2 and the common power feed line L4 are electrically connected. When the second switch 12 is turned off, the second switch 12 cuts off the electrical connection between the second power feed line L2 and the common power feed line L4.

[0020] 1, the second switch 12 is a switch having a configuration in which a first FET (Field Effect Transistor) 121 and a second FET 122 are connected in a so-called back-to-back manner. Specifically, the second switch 12 is configured by a series circuit of the first FET 121, the cathode of which is connected to the second power supply 20, and the second FET 122, the anode of which is connected to the second power supply 20. Note that, although an example in which only the second switch 12 is a series circuit of the first FET 121 and the second FET 122 is shown in FIG. 1, the first switch 11 and the third to sixth switches 13 to 16 may also be configured by a series circuit of the first FET 121 and the second FET 122.

[0021] The third to sixth switches 13 to 16 are switches that connect the load power supply line L3 and the common power supply line L4. Specifically, the third switch 13, when turned on, electrically connects the common power supply line L4 and the first load 41. Moreover, the third switch 13, when turned off, cuts off the electrical connection between the common power supply line L4 and the first load 41.

[0022] The fourth switch 14, when turned on, electrically connects the common power supply line L4 and the second load 42. In addition, the fourth switch 14, when turned off, electrically disconnects the common power supply line L4 and the second load 42.

[0023] The fifth switch 15, when turned on, electrically connects the common power supply line L4 and the third load 43. In addition, the fifth switch 15, when turned off, electrically disconnects the common power supply line L4 and the third load 43.

[0024] The sixth switch 16, when turned on, electrically connects the common power supply line L4 and the fourth load 44. In addition, the sixth switch 16, when turned off, electrically disconnects the common power supply line L4 and the fourth load 44.

[0025] The first sensor 51 is provided on the first power supply line L1 and detects the power supply state. Here, the first sensor 51 is a voltage sensor that detects the voltage of the first power supply line L1 (the voltage of the first power source 10). The first sensor 51 outputs the voltage detection result to the controller 3. Note that the first sensor 51 may be a current detection sensor that detects the current of the first power supply line L1. In this case, the first sensor 51 outputs the current detection result to the controller 3.

[0026] The second sensor 52 is provided on the second power supply line L2 and detects the power supply state. Here, the second sensor 52 is a voltage sensor that detects the voltage of the second power supply line L2 (the voltage of the second power source 20). The second sensor 52 outputs the voltage detection result to the controller 3. Note that the second sensor 52 may be a current detection sensor that detects the current of the second power supply line L2. In this case, the second sensor 52 outputs the current detection result to the controller 3.

[0027] The third sensor 53 is provided on the common power supply line L4 and detects the power supply state. Here, the third sensor 53 is a voltage sensor that detects the voltage of the common power supply line L4. The third sensor 53 outputs the voltage detection result to the controller 3. Note that the third sensor 53 may be a current detection sensor that detects the current of the common power supply line L4. In this case, the third sensor 53 outputs the current detection result to the controller 3.

[0028] The fourth sensor 54 is provided on the load power supply line L3 between the third switch 13 and the first load 41, and detects the power supply state. Here, the fourth sensor 54 is a voltage sensor that detects the voltage of the load power supply line L3 between the third switch 13 and the first load 41. The fourth sensor 54 outputs the voltage detection result to the controller 3. Note that the fourth sensor 54 may be a current detection sensor that detects the current of the load power supply line L3 between the third switch 13 and the first load 41. In this case, the fourth sensor 54 outputs the current detection result to the controller 3.

[0029] The fifth sensor 55 is provided on the load power supply line L3 between the fourth switch 14 and the second load 42, and detects the power supply state. Here, the fifth sensor 55 is a voltage sensor that detects the voltage of the load power supply line L3 between the fourth switch 14 and the second load 42. The fifth sensor 55 outputs the voltage detection result to the controller 3. Note that the fifth sensor 55 may be a current detection sensor that detects the current of the load power supply line L3 between the fourth switch 14 and the second load 42. In this case, the fifth sensor 55 outputs the current detection result to the controller 3.

[0030] The sixth sensor 56 is provided on the load power supply line L3 between the fifth switch 15 and the third load 43, and detects the power supply state. Here, the sixth sensor 56 is a voltage sensor that detects the voltage of the load power supply line L3 between the fifth switch 15 and the third load 43. The sixth sensor 56 outputs the voltage detection result to the controller 3. Note that the sixth sensor 56 may be a current detection sensor that detects the current of the load power supply line L3 between the fifth switch 15 and the third load 43. In this case, the sixth sensor 56 outputs the current detection result to the controller 3.

[0031] The seventh sensor 57 is provided on the load power supply line L3 between the sixth switch 16 and the fourth load 44, and detects the power supply state. Here, the seventh sensor 57 is a voltage sensor that detects the voltage of the load power supply line L3 between the sixth switch 16 and the fourth load 44. The seventh sensor 57 outputs the voltage detection result to the controller 3. Note that the seventh sensor 57 may be a current detection sensor that detects the current of the load power supply line L3 between the sixth switch 16 and the fourth load 44. In this case, the seventh sensor 57 outputs the current detection result to the controller 3.

[0032] Among the first sensor 51 to the seventh sensor 57, the third sensor 53 or any of the fourth sensor 54 to the seventh sensor 57 may be omitted. When the fourth sensor 54 to the seventh sensor 57 are omitted, the power supply control device 1 can identify the load power supply line L3 in which a ground fault has occurred by sequentially turning off the third switch 13 to the sixth switch 16 and monitoring the voltage value detected by the third sensor 53.

[0033] The controller 3 includes a microcomputer having a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), etc., and various circuits. The controller 3 performs on / off control of the first to sixth switches 11 to 16 by the CPU executing a power control program stored in the ROM using the RAM as a working area.

[0034] The power supply control program may be stored in a storage device from the outside via a communication line, etc. Also, the controller 3 may be partially or entirely configured with hardware such as an ASIC (Application Specific Integrated Circuit) or an FPGA (Field Programmable Gate Array).

[0035] [Basic operation example of the power supply control system according to the embodiment] Next, a basic operation of the power supply control system S will be described. In the present disclosure, the power supply control system S supplies power input from the first power supply 10 to the first to fourth loads 41 to 44 during a period when the IG of the vehicle is on and during normal operation when no ground fault occurs in the power supply lines L1 to L3. Specifically, the controller 3 turns on the first to sixth switches 11 to 16 during normal operation.

[0036] At this time, as described above, since the voltage of the first power source 10 is slightly higher than the voltage of the second power source 20, the controller 3 supplies power from the first power source 10 to the first to fourth loads 41 to 44, and does not supply power from the second power source 20 to the first to fourth loads 41 to 44. Note that if the voltage of the first power source 10 temporarily drops below the voltage of the second power source 20 due to an instantaneous interruption or the like, power will be supplied from the second power source 20 to the first to fourth loads 41 to 44.

[0037] On the other hand, when a ground fault occurs in the first power supply line L1, the power supply control device 1 cannot supply power from the first power supply 10 (because the voltage of the first power supply 10 becomes zero), so the second power supply 20 supplies power to the first to fourth loads 41 to 44. In this case, the controller 3 turns off only the first switch 11 from a state in which the first to sixth switches 11 to 16 are turned on. As a result, the power output from the second power supply 20 is continuously supplied to the first to fourth loads 41 to 44 via the second switch 12, the common power supply line L4, the third to sixth switches 13 to 16, and the load power supply line L3 without being discharged to the first power supply line L1.

[0038] Furthermore, when a ground fault occurs in the second power supply line L2, the power supply control device 1 continues power supply from the first power supply 10 to the first to fourth loads 41 to 44 while suppressing discharge from the first power supply 10 to the second power supply line L2.

[0039] In this case, the controller 3 turns off only the second switch 12 while keeping the first to sixth switches 11 to 16 on. As a result, the power output from the first power supply 10 is continuously supplied to the first to fourth loads 41 to 44 via the first switch 11, the common power supply line L4, the third to sixth switches 13 to 16, and the load power supply line L3 without being discharged to the second power supply line L2.

[0040] Furthermore, when a ground fault occurs in the load power supply line L3, the power supply control device 1 identifies the location of the ground fault in the load power supply line L3, and turns off the switch connected to the identified line L3 among the third to sixth switches 13 to 16, thereby disconnecting the line L3 from the common power supply line L4 and continuing power supply through the load power supply line L3 where no ground fault occurs. The location of the ground fault can be identified based on the voltages detected by the fourth to seventh sensors 54 to 57.

[0041] [Example of operation for suppressing inrush current] Next, an example of operation for suppressing the occurrence of an inrush current will be described with reference to Fig. 1 to Fig. 5. Fig. 1 shows the operation of the power supply control system S when the IG of the vehicle is turned off, and Fig. 2 to Fig. 5 show the operation of the power supply control system S when the IG of the vehicle is turned on.

[0042] 1, when IG is off, the power supply control device 1 supplies power from the second power supply 20 to the fourth load 44 that needs to be operated while IG is off, and does not supply power from the first power supply 10. Specifically, the power supply control device 1 turns on the first FET 121 and the second FET 122 of the second switch 12 and the sixth switch 16, and turns off the first switch 11 and the third to fifth switches 13 to 15. At this time, since the second power supply 20 is not charged by the first power supply 10, the voltage of the second power supply 20 decreases as power is supplied to the fourth load 44.

[0043] Next, as shown in FIG. 2, it is assumed that the IG is turned on. At this time, the power supply control device 1 first calculates the voltage difference between the voltage of the first power supply 10 and the voltage of the second power supply 20, and compares both voltages. Specifically, the power supply control device 1 calculates the voltage difference from the voltage of the first power supply 10 detected by the first sensor 51 and the voltage of the second power supply 20 detected by the second sensor 52. As shown in FIG. 2, when the voltage difference between the voltage of the first power supply 10 and the voltage of the second power supply 20 is less than a threshold value, the power supply control device 1 switches the first switch 11 on and keeps the second switch 12 on. This makes it possible to supply power from the first power supply 10 in addition to the second power supply 20. Furthermore, the power supply control device 1 turns on the fourth switch 14 and the fifth switch 15 among the third to fifth switches 13 to 15. In other words, the power supply control device 1 starts power supply to the second load 42 and the third load 43, which have low power consumption (less than the threshold) immediately after startup, among the first load 41 to the third load 43, and does not start power supply to the first load 41, which has high power consumption. In other words, the power supply control device 1 starts power supply to loads with high priority (low power consumption), and does not start power supply to loads with low priority (high power consumption). In this case, it is desirable to turn on the first switch 11, and then turn on the fourth switch 14 and the fifth switch 15 after a short delay. This makes it possible to suppress a sudden increase in the current output from the first power supply 10.

[0044] In this way, the power supply control device 1 supplies power only to the second load 42 and the third load 43, which have higher priority, after the IG is turned on, and does not supply power to the first load 41, which has lower priority. This reduces the sum of the currents output from the first power source 10 to each load by the amount of the first load 41. In other words, in the present disclosure, the number of loads to which power is supplied after the IG is turned on is reduced, and the sum of the currents output from the first power source 10 to each load is reduced, thereby suppressing the occurrence of inrush current.

[0045] Furthermore, the power supply control device 1 can minimize the total current output from the first power source 10 by treating loads with high power consumption as low priority loads and not supplying power to them, thereby further suppressing the occurrence of inrush current.

[0046] The priority is not limited to the example determined based on the magnitude relationship of power consumption. For example, the priority may be set to a high priority for a load essential for vehicle driving control (such as an engine control device) and a low priority for a load not essential for vehicle driving control (such as a window opening / closing device or a wiper control device). The priority may also be set to a high priority for a load arbitrarily selected from among all loads and a low priority for the remaining loads. Alternatively, the priority may be set to a high priority for a combination of loads that results in a sum of currents output from the first power source 10 being less than a threshold value.

[0047] Next, as shown in FIG. 3, when the voltage of the first power supply 10 is higher than the voltage of the second power supply 20 by a threshold or more (when the voltage difference is a threshold or more), the power supply control device 1 reduces the voltage of the first power supply 10. Specifically, the power supply control device 1 reduces the step-down target voltage of the DCDC 102 of the first power supply 10 from a first voltage value to a second voltage value. Here, the second voltage value is set to be the same as the voltage of the second power supply 20 (the voltage detected by the second sensor 52) or a slightly higher value (for example, a voltage difference of about 0.5 to 1 V). In other words, the power supply control device 1 reduces the voltage of the first power supply 10 to the second voltage value when the voltage of the second power supply 20 is reduced by power supply during IG off and the voltage difference with the voltage of the first power supply 10 (first voltage value) becomes a threshold or more when the IG is turned on.

[0048] Next, after the voltage of the first power supply 10 is reduced to the second voltage value, the power supply control device 1 turns on the first switch 11, the fourth switch 14, and the fifth switch 15 to start supplying power to the second load 42 and the third load 43. In other words, the power supply control device 1 starts supplying power to the second load 42 and the third load 43, which have low power consumption (less than the threshold) immediately after starting up, among the first load 41 to the third load 43, and does not start supplying power to the first load 41, which has high power consumption. In other words, the power supply control device 1 starts supplying power to a load with a high priority (low power consumption), and does not start supplying power to a load with a low priority (high power consumption). Note that, in this case as well, it is desirable to turn on the first switch 11, and then turn on the fourth switch 14 and the fifth switch 15 after a short delay. This makes it possible to suppress a sudden increase in the current output from the first power supply 10.

[0049] In this way, the power supply control device 1 supplies power only to the second load 42 and the third load 43, which have higher priority, after the IG is turned on, and does not supply power to the first load 41, which has lower priority. This reduces the sum of the currents output from the first power source 10 to each load by the amount of the first load 41. In other words, in the present disclosure, the number of loads to which power is supplied after the IG is turned on is reduced, and the sum of the currents output from the first power source 10 to each load is reduced, thereby suppressing the occurrence of inrush current.

[0050] Furthermore, the power supply control device 1 can minimize the total current output from the first power source 10 by treating loads with high power consumption as low priority loads and not supplying power to them, thereby further suppressing the occurrence of inrush current.

[0051] Moreover, the power supply control device 1 turns off only the second FET 122 of the second switch 12. This makes it possible to prevent current from flowing from the first power supply 10 to the second power supply 20. Moreover, the power supply control device 1 turns on the first FET 121 of the second switch 12 and turns off the second FET 122, thereby switching the first power supply 10 to a state in which power can be supplied while maintaining a state in which power can be supplied from the second power supply 20. This makes it possible to prevent an instantaneous interruption from occurring when the power supply to the fourth load 44 is switched from the second power supply 20 to the first power supply 10. Note that the power supply control device 1 may turn off the first FET 121 and the second FET 122 (i.e., turn off the second switch 12). This makes it possible to prevent current from flowing from the first power supply 10 to the second power supply 20.

[0052] Next, as shown in Fig. 4, the power supply control device 1 starts power supply from the first power source 10 to the second to fourth loads 42 to 44, and after a certain time has elapsed, turns on the third switch 13 to supply power to the first load 41. The certain time is a time during which an inrush current generated with power supply to the second to fourth loads 42 to 44 is assumed to converge, and is, for example, a time obtained in advance by an experiment or the like. In other words, the power supply control device 1 turns on the third switch 13 to supply power to the first load 41 after an inrush current generated by starting power supply to the second to fourth loads 42 to 44 converges. This makes it possible to suppress an inrush current generated when starting power supply to the first load 41, which consumes a large amount of power.

[0053] Next, as shown in FIG. 5, the power supply control device 1 turns on the second FET 122 of the second switch 12 after a certain time has elapsed since the start of power supply to the first load 41. The certain time is a time during which an inrush current generated with the power supply to the first load 41 is assumed to converge, and is, for example, a time obtained in advance by an experiment or the like. In addition, the power supply control device 1 returns the step-down target voltage of the DCDC 102 from the second voltage value to the first voltage value. That is, the power supply control device 1 starts charging the second power source 20 after the inrush current generated by starting power supply to the first load 41 converges. This makes it possible to suppress the inrush current generated when charging the second power source 20 from the first power source 10.

[0054] Next, the operation timing of each component in the power supply control system S will be described with reference to Fig. 6. Fig. 6 is a timing chart showing the operation of the power supply control system S. Fig. 6 shows, from the top, the voltage changes of the first power supply 10 and the second power supply 20, the current changes flowing through the common power supply line L4, and the on / off states of the first switch 11 to the sixth switch 16. Fig. 6 also shows the switch state of the second FET 122 of the second switch 12, and it is assumed that the first FET 121 is always on. It is to be noted that in Fig. 6, IG is off until time t1, and IG is on after time t1.

[0055] 6, in the period until time t1 when IG is off, the first switch 11 and the third to fifth switches 13 to 15 are off, and the second switch 12 (second FET 122) and the sixth switch 16 are on. As a result, power is supplied from the second power source 20 to the fourth load 44 via the sixth switch 16, and no power is supplied from the first power source 10. As a result, the voltage of the second power source 20 continues to decrease in the period until time t1.

[0056] Next, at time t1 when the IG is turned on, if the voltage difference between the first power supply 10 and the second power supply 20 is equal to or greater than the threshold, the controller 3 reduces the voltage of the first power supply 10 to a value equal to or slightly higher than the voltage of the second power supply 20. Specifically, the controller 3 reduces the step-down target voltage of the DCDC 102 from the first voltage value to the second voltage value. Then, the controller 3 turns on the first switch 11 at time t1. As a result, the first power supply 10 is in a state in which it can supply power. Specifically, by turning on the first switch 11, a current flows from the first power supply 10 to the fourth load instead of the second power supply 20. Alternatively, a current flows from the first power supply 10 and the second power supply 20 to the fourth load. Also, the controller 3 turns off the second FET 122 of the second switch 12 at time t1. This allows the controller 3 to avoid an inrush current from the first power source 10 to the second power source 20 while maintaining a state in which power can be supplied from the second power source 20. Furthermore, by maintaining a state in which power can be supplied from the second power source 20, the controller 3 can avoid a momentary interruption in the power supply to the fourth load 44 when power supply to the fourth load 44 is switched to the first power source 10.

[0057] Next, at time t2, which is a predetermined time after time t1, the controller 3 turns on the fourth switch 14 and the fifth switch 15 to supply power from the first power source 10 to the second load 42 and the third load 43. That is, immediately after IG is turned on, the controller 3 starts supplying power to the second load 42 and the third load 43, which consume less power immediately after startup, and does not supply power to the first load 41, which consumes more power. This allows the controller 3 to reduce the total sum of currents supplied from the first power source 10 to each load by the amount of the first load 41, thereby suppressing the occurrence of inrush current. Note that, although FIG. 6 shows an example in which the fourth switch 14 and the fifth switch 15 are turned on at time t2, which is a predetermined time after time t1, the controller 3 may turn on the fourth switch 14 and the fifth switch 15 at time t1. Then, after time t2, the current flowing through the common power supply line L4 increases by the amount of power supplied to the second load 42 and the third load 43.

[0058] Next, at time t3, a predetermined time after time t2, the controller 3 turns on the third switch 13 to supply power from the first power source 10 to the first load 41. The predetermined time from time t2 to time t3 is equal to or longer than the time required for an inrush current generated when power supply to the second load 42 and the third load 43 is started to converge. In other words, after starting power supply to the second load 42 and the third load 43, the controller 3 starts supplying power to the first load 41, which consumes large power, a predetermined time after the inrush current converges. As a result, the current that rises after time t3 is only the amount of power supplied to the first load 41, and therefore the controller 3 can minimize the increase in current, thereby suppressing the occurrence of an inrush current.

[0059] After time t3, the current flowing through the common power supply line L4 increases as the supply of power to the first load 41 starts. Next, at time t4, which is a predetermined time after time t3, the controller 3 restores the voltage of the first power supply 10 that has been lowered. Specifically, the controller 3 increases (restores) the step-down target voltage of the DCDC 102 from the second voltage value to the first voltage value. In addition, the controller 3 turns on the second FET 122 of the second switch 12 at time t4. As a result, the voltage of the first power supply 10 becomes higher than that of the second power supply 20, and charging from the first power supply 10 to the second power supply 20 starts. Then, after time t4, the current increases by the amount of charging to the second power supply 20, and the voltage of the second power supply 20 increases as the second power supply 20 is charged. Note that the predetermined time from time t3 to time t4 is equal to or longer than the time during which an inrush current generated when the supply of power to the first load 41 starts is expected to converge. That is, the controller 3 starts charging the second power source 20 a predetermined time after the start of power supply to the first load 41 and the inrush current converges. As a result, the current that increases after time t4 is only the amount of current charged in the second power source 20, and the controller 3 can minimize the amount of current increase, thereby suppressing the occurrence of inrush current.

[0060] Then, at time t5, a predetermined time after time t4, the voltage of the second power supply 20 rises to the same voltage (or a slightly lower voltage) as that of the first power supply 10. As a result, the voltage difference between the first power supply 10 and the second power supply 20 disappears (or becomes small), and charging from the first power supply 10 to the second power supply 20 ends. As a result, the current after time t5 decreases by the amount of charge of the second power supply 20.

[0061] Next, the flow of processing executed by the power supply control device 1 will be described with reference to Fig. 7. Fig. 7 is a flowchart showing the procedure of power supply processing executed by the power supply control device 1 according to the embodiment. The processing shown in Fig. 7 is performed when the IG of the vehicle is switched from off to on. Also, Fig. 7 starts from a state in which the IG of the vehicle is off, the second switch 12 and the sixth switch 16 are on, and the first switch 11 and the third to fifth switches 13 to 15 are off.

[0062] 7, when the IG of the vehicle is turned on, the controller 3 first acquires the voltages of the first power source 10 and the second power source 20 (step S101). Specifically, the controller 3 acquires the voltage detected by the first sensor 51 as the voltage of the first power source 10, and acquires the voltage detected by the second sensor 52 as the voltage of the second power source 20.

[0063] Next, the controller 3 determines whether or not the voltage difference between the first power source 10 and the second power source 20 is equal to or greater than a threshold value (step S102). That is, the controller 3 determines whether or not the voltage of the first power source 10 is higher than the voltage of the second power source 20 by equal to or greater than the threshold value.

[0064] When the voltage difference between the first power supply 10 and the second power supply 20 is equal to or greater than the threshold (step S102: Yes), the controller 3 reduces the step-down target voltage of the DCDC 102 from the first voltage value to the second voltage value (step S103).

[0065] Next, the controller 3 turns on the first switch 11 and turns off the second FET 122 of the second switch 12 (step S104). That is, the controller 3 turns on the first switch 11 to enable power supply from the first power source 10, and turns off the second FET 122 to prevent a rush current from flowing into the second power source 20 while continuing the power supply from the second power source 20.

[0066] Next, the controller 3 turns on the fourth switch 14 and the fifth switch 15 (step S105). That is, the controller 3 supplies power from the first power supply 10 to the second load 42 and the third load 43, which have low power consumption (less than the threshold).

[0067] Next, the controller 3 determines whether or not a certain time has elapsed after the first power source 10 starts supplying power to the second load 42 and the third load 43 (step S106). The certain time is a time during which the inrush currents to the second load 42 and the third load 43 are assumed to converge.

[0068] If the certain time has elapsed (step S106: Yes), the controller 3 turns on the third switch 13 (step S107). That is, the controller 3 starts supplying power from the first power source 10 to the first load 41 that consumes large power (above a threshold). If the certain time has not elapsed (step S106: No), the controller 3 repeatedly executes step S106 until the certain time has elapsed.

[0069] Next, after starting the power supply to the first load 43, the controller 3 turns on the second FET 122 of the second switch 12 (step S108) and returns the step-down target voltage of the DCDC 102 from the second voltage value to the first voltage value (step S109). That is, the controller 3 starts charging the second power source 20 from the first power source 10.

[0070] On the other hand, in step S102, if the voltage difference between the first power source 10 and the second power source 20 is less than the threshold value (step S102: No), the controller 3 turns on the first switch 11 (step S110). That is, by turning on the first switch 11, the controller 3 makes it possible to supply power from the first power source 10.

[0071] Next, the controller 3 turns on the fourth switch 14 and the fifth switch 15 (step S111). That is, the controller 3 supplies power from the first power supply 10 to the second load 42 and the third load 43, which have low power consumption (less than the threshold).

[0072] Next, the controller 3 determines whether or not a certain time has elapsed after starting the power supply from the first power source 10 to the second load 42 and the third load 43 (step S112). The certain time is a time during which the inrush current to the second load 42 and the third load 43 is assumed to converge.

[0073] If the certain time has elapsed (step S112: Yes), the controller 3 turns on the third switch 13 (step S113). That is, the controller 3 starts supplying power from the first power source 10 to the first load 43 that consumes large power (above the threshold). If the certain time has not elapsed (step S112: No), the controller 3 repeatedly executes step S112 until the certain time has elapsed.

[0074] As described above, the power supply control device 1 is a power supply control device that controls the power supply from the first power source 10 to the load of the vehicle via the first power source switch (first switch 11) and the power supply from the second power source 20 to the load via the second power source switch (second switch 12), and has a controller 3. When the IG of the vehicle is off, the controller 3 turns on the second power source switch to supply power from the second power source 20 to the first load (fourth load 44), and when the IG is on, turns on the first power source switch to supply power from the first power source 10 to the second load (first to fourth loads 41 to 44). When the IG is on and the voltage of the first power source 10 is higher than the voltage of the second power source 20 by a threshold value or more, the controller 3 reduces the voltage of the first power source 10 to the voltage of the second power source 20 and then turns on the first power source switch, and supplies power from the first power source 10 only to the second load having a higher predetermined priority among the second loads.

[0075] In the present disclosure, after the IG is turned on, power is supplied only to the loads with high priority, and power is not supplied to the loads with low priority. This reduces the number of loads to which power is supplied after the IG is turned on, and the total sum of the currents output from the first power source to each load is reduced, thereby suppressing the occurrence of inrush current.

[0076] In the above-described embodiment, the power supply control device 1 has been described as controlling the first switch 11 to the sixth switch 16 by one controller 3, but the present invention is not limited to this, and the first switch 11 to the sixth switch 16 may be controlled by a plurality of controllers. This point will be described with reference to FIG. 8.

[0077] Fig. 8 is a diagram showing an example of the configuration of a power supply control device 1 according to a modified example. As shown in Fig. 8, the power supply control device 1 may be configured to include a first unit 110 to a third unit 130, each of which has a controller.

[0078] The first unit 110 includes a first controller 31, a first switch 11, and a second switch 12. The second unit 120 includes a second controller 32, a third switch 13, and a fourth switch 14. The third unit 130 includes a third controller 33, a fifth switch 15, and a sixth switch 16.

[0079] The first controller 31 controls the first switch 11 and the second switch 12 based on the voltages detected by the first sensor 51 and the second sensor 52. For example, when the first controller 31 detects a power failure of the first power source 10 or the second power source 20 based on the voltages detected by the first sensor 51 and the second sensor 52, the first controller 31 turns off the switch of the power source in which the power failure has occurred.

[0080] The second controller 32 controls the third switch 13 and the fourth switch 14 based on the voltages detected by the fourth sensor 54 and the fifth sensor 55. For example, the second controller 32 detects a ground fault in the load power supply lines connected to the first load 41 and the second load 42, respectively, based on the voltages detected by the fourth sensor 54 and the fifth sensor 55, and turns off the switch of the load power supply line in which the ground fault occurs.

[0081] The third controller 33 controls the fifth switch 15 and the sixth switch 16 based on the voltages detected by the sixth sensor 56 and the seventh sensor 57. For example, the second controller 32 detects a ground fault in the load power supply lines connected to the third load 43 and the fourth load 44, respectively, based on the voltages detected by the sixth sensor 56 and the seventh sensor 57, and turns off the switch of the load power supply line in which the ground fault occurs.

[0082] Furthermore, the first controller 31 to the third controller 33 acquire IG on / off information and control the switch that they are responsible for controlling among the first switch 11 to the sixth switch 16 at the timing shown in Fig. 6. Any one of the first controller 31 to the third controller 33 may be configured as a master and the rest as slaves. In this case, the master controller acquires and manages the control state of each switch from the slave controller.

[0083] 8 shows a configuration in which the power supply control device 1 includes the first unit 110 to the third unit 130, but the number of units may be arbitrary. For example, the power supply control device 1 may include a unit corresponding to each switch (the number of units is six in the case of FIG. 8). Furthermore, the number of switches controlled by each unit does not have to be the same, and each unit may control a different number of switches.

[0084] Further advantages and modifications may readily occur to those skilled in the art. Thus, the invention in its broader aspects is not limited to the specific details and representative embodiments shown and described above. Accordingly, various modifications may be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and equivalents thereof. [Explanation of symbols]

[0085] 1 Power supply control device 3. Controller 10 1st power supply 11 First Switch 12 Second Switch 13 Third Switch 14 4th Switch 15 5th Switch 16 6th Switch 20 2nd power supply 31 First Controller 32 Second Controller 33 Third Controller 41 1st load 42 2nd load 43 Third load 44 4th load 51 First Sensor 52 Second Sensor 53 3rd Sensor 54 4th Sensor 55 5th Sensor 56 6th Sensor 57 7th Sensor 101 1st battery 110 Unit 1 120 Unit 2 121 1st FET 122 2nd FET 130 Unit 3 201 Second Battery L1 First power supply line L2 Second power supply line L3 Load supply line L4 Common power supply line S Power supply control system

Claims

1. A power supply control device that controls power supply from a first power source to a load of a vehicle via a first power source switch and power supply from a second power source to the load via a second power source switch, Has a controller The controller: When an IG of the vehicle is off, the second power supply switch is turned on to supply power from the second power supply to the first load, and when the IG is turned on, the first power supply switch is turned on to supply power from the first power supply to the second load; When the IG is turned on, if the voltage of the first power supply is higher than the voltage of the second power supply by a threshold value or more, the voltage of the first power supply is reduced to the voltage of the second power supply, and then the first power supply switch is turned on, and power is supplied from the first power supply only to the second load having a higher predetermined priority among the second loads. Power control device.

2. The controller: After starting the power supply to the second load having the higher priority, and after a time period during which an inrush current is expected to converge has elapsed, power is supplied from the first power source to the remaining second loads. The power supply control device according to claim 1 .

3. The second load having the higher priority is The load whose power consumption after startup is less than a threshold value The power supply control device according to claim 1 .

4. The controller: When the IG is turned on, if the voltage of the first power supply is higher than the voltage of the second power supply by a threshold value or more, the first power supply switch is turned on and the second power supply switch is turned off. The power supply control device according to claim 1 .

5. The second power switch is a first FET having a parasitic diode whose cathode is connected to the second power supply side and a second FET having a parasitic diode whose anode is connected to the second power supply side; The controller: When the IG is off, the first FET and the second FET are turned on, and when the IG is turned on, if the voltage of the first power supply is higher than the voltage of the second power supply by a threshold value or more, the first power supply switch is turned on and the second FET is turned off. The power supply control device according to claim 4.

6. The controller: After starting to supply power to all of the second loads, the second FET is turned on. The power supply control device according to claim 5.

7. The controller: The second FET is turned on, and the voltage of the first power supply that has been reduced is restored. The power supply control device according to claim 6.

8. the first power supply includes a first battery and a converter that generates a voltage of the first power supply by stepping down a voltage of the first battery; The controller: When the voltage of the first power source is higher than the voltage of the second power source by a threshold value or more, the voltage of the first power source is reduced by reducing a step-down target voltage of the converter from a first voltage value to a second voltage value, and when the voltage of the first power source is restored, the step-down target voltage of the converter is increased from the second voltage value to the first voltage value. The power supply control device according to claim 7.

9. A power supply control program to be executed by a power supply control device that controls power supply from a first power supply to a load of a vehicle via a first power supply switch and power supply from a second power supply to the load via a second power supply switch, When an IG of the vehicle is off, the second power supply switch is turned on to supply power from the second power supply to the first load, and when the IG is turned on, the first power supply switch is turned on to supply power from the first power supply to the second load; When the IG is turned on, if the voltage of the first power supply is higher than the voltage of the second power supply by a threshold value or more, the voltage of the first power supply is reduced to the voltage of the second power supply, and then the first power supply switch is turned on, and power is supplied from the first power supply only to the second load having a higher predetermined priority among the second loads. Power control program.

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