Power supply control device, power supply control method and control program

Abstract

To provide a power supply control unit and a power supply control method, capable of highly accurately detecting a system failure.SOLUTION: A power supply control unit according to an embodiment includes a first system, a second system, a system switch and a control part. The first system includes a first battery and supplies power from the first battery to a load. The second system includes a second battery and supplies power from the second battery to the load. The system switch switches the first system and the second system. The control part controls to shut off the system switch if an over current is detected in the first system or the second system. The control part corrects a threshold for detecting the over current depending on the condition of the first battery or the second battery.SELECTED DRAWING: Figure 1

Description

[Technical Field]

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

[0002] Conventionally, for example, in consideration of power supply failure during automatic operation, a redundant power supply technology with two power supply systems has been proposed (see, for example, Patent Document 1). With this type of technology, when the current value flowing through each system exceeds a predetermined threshold, one of the failed systems is disconnected and power is supplied from the other system. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2017-61240 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, the conventional technology has room for improvement in terms of detecting grid failures with high accuracy.

[0005] The present invention has been made in view of the above, and has an object to provide a power supply control device and a power supply control method that can detect a system failure with high accuracy. [Means for solving the problem]

[0006] In order to solve the above-mentioned problems and achieve the object, the power supply control device of the present invention comprises a first system, a second system, a system switch, and a control unit. The first system includes a first battery and supplies power from the first battery to a load. The second system includes a second battery and supplies power from the second battery to the load. The system switch connects and disconnects the first system and the second system. When the control unit detects an overcurrent in the first system or the second system, it controls the system switch to turn off. The control unit corrects the threshold for detecting the overcurrent depending on the state of the first battery or the second battery. [Effects of the Invention]

[0007] According to the present invention, a system failure can be detected with high accuracy. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a diagram illustrating an example of the configuration of a power supply control device according to an embodiment. [Figure 2] FIG. 2 is a diagram illustrating an example of the configuration of a power supply control device according to an embodiment. [Figure 3] FIG. 3 is a diagram illustrating an example of the configuration of a power supply control device according to an embodiment. [Figure 4] FIG. 4 is a diagram illustrating a method for correcting the current threshold. [Figure 5] FIG. 5 is a diagram illustrating a power supply control device 1 according to a first modified example. [Figure 6] FIG. 6 is a diagram illustrating a power supply control device 1 according to a second modified example. [Figure 7] FIG. 7 is a diagram illustrating a method for correcting the voltage threshold. [Figure 8] FIG. 8 is a diagram illustrating a power supply control device 1 according to a third modified example. DETAILED DESCRIPTION OF THE INVENTION

[0009] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A power supply control device and a power supply control method according to embodiments of the present invention will be described in detail below with reference to the accompanying drawings. However, the present invention is not limited to the following embodiments.

[0010] First, a configuration example of a power supply control device according to an embodiment will be described with reference to Figures 1 to 3. Figures 1 to 3 are diagrams showing a configuration example of a power supply control device according to an embodiment. A power supply control device 1 according to an embodiment is a device mounted on a vehicle, and executes a power supply control method according to an embodiment.

[0011] As shown in FIG. 1, a power supply control device 1 according to the embodiment is connected to a first load 100 and a second load 200, and supplies power to the first load 100 and the second load 200, respectively.

[0012] The first load 100 is, for example, a load related to the forward or reverse movement of the vehicle, or a load not related to the vehicle's running (forward or backward movement, turning, and stopping). The load related to the forward or reverse movement is, for example, an engine ECU (Electronic Control Unit), a transmission ECU, etc. The load not related to the running is, for example, an air conditioner, wipers, power windows, etc.

[0013] The second load 200 is a load related to turning, stopping, and automatic driving of the vehicle. The load related to turning is, for example, an EPS (Electric Power Steering). The load related to stopping is, for example, a brake ECU. The load related to automatic driving is, for example, a radar, a camera, etc.

[0014] The second load 200 includes a load that allows the vehicle to perform FOP (Fail Operational) running, such as evacuation running, when a power source fails or the like.

[0015] The power supply control device 1 according to the embodiment includes a control unit 2, a high-voltage battery 3, a DC-DC converter 4, a PbB 5, an LiB 6, diodes 7 and 8, a system switch SW1, and a battery switch SW2.

[0016] Here, the power supply control device 1 includes, for example, a computer having a central processing unit (CPU), read only memory (ROM), random access memory (RAM), flash memory, input / output ports, and various other circuits.

[0017] The CPU of the computer functions as the control unit 2 by, for example, reading and executing a program stored in the ROM.

[0018] Furthermore, at least one or all of the functions of the control unit 2 can be configured using hardware such as an ASIC (Application Specific Integrated Circuit) or an FPGA (Field Programmable Gate Array).

[0019] The power supply control device 1 also has a storage unit (not shown), which corresponds to a RAM or flash memory. The RAM or flash memory can store information about various programs. The power supply control device 1 may also acquire the above-mentioned programs and various information via another computer or portable recording medium connected via a wired or wireless network.

[0020] The high-voltage battery 3 is a secondary battery that supplies power to the first load 100 and the second load 200. The high-voltage battery 3 is a battery with a higher voltage value than PbB5 and LiB6, which will be described later. The high-voltage battery 3, together with PbB5, which will be described later, is an example of a first battery.

[0021] The DC-DC converter 4 steps down the voltage of the high-voltage battery 3 in accordance with the voltage required by the first load 100 or the second load 200.

[0022] PbB5 is a lead-acid battery that supplies power to the first load 100 and the second load 200. As described above, PbB5 is an example of the first battery. LiB6 is a lithium-ion battery that supplies power to the second load 200 in the event of a power failure in the first system, which will be described later. LiB6 is an example of the second battery.

[0023] The diodes 7 and 8 are diodes for preventing reverse current. Specifically, the diode 7 has a cathode connected to the second load 200 and an anode connected to the DC-DC converter 4 and PbB 5. The diode 8 has a cathode connected to the second load 200 and an anode connected to the system switch SW1 and the battery switch SW2.

[0024] In the following description, the system for supplying power from the high-voltage battery 3 and PbB5 to the first load 100 and the second load 200 will be referred to as the first system, and the path for supplying power from the LiB6 to the second load 200 will be referred to as the second system.

[0025] 1, the first system is provided with a current sensor S1, and the second system is provided with a current sensor S2. A control unit 2, which will be described later, determines whether a power failure has occurred in each of the first system and the second system based on the current values ​​detected by the current sensors S1 and S2.

[0026] The system switch SW1 is a switch that separates the first system from the second system. When a power failure occurs in the first system or the second system, the system switch SW1 cuts off the power, thereby separating the first system from the second system.

[0027] The battery switch SW2 is a switch that connects and disconnects the LiB 6 from the second system. The battery switch SW2 is connected when the power supply of the first system fails, so that power is supplied from the LiB 6 to the second load 200.

[0028] An example of the operation of the power supply control device 1 will now be described with reference to Figures 1 to 3. Figure 1 shows a normal state, i.e., a state where there is no power failure in the first and second systems, Figure 2 shows a state where there is a power failure in the first system, and Figure 3 shows a state where there is a power failure in the second system. Note that the power failure here refers to a power failure caused by a ground fault occurring in a system.

[0029] First, an example of the operation of the power supply control device 1 under normal conditions will be described using Fig. 1. As shown in Fig. 1, under normal conditions, the control unit 2 of the power supply control device 1 connects the system switch SW1 and disconnects the battery switch SW2. Under normal conditions, the current values ​​of the current sensors S1 and S2 are each below a predetermined current threshold.

[0030] As a result, during normal operation, power is supplied from the high-voltage battery 3 and PbB5 to the first load 100 and the second load 200 via the first system. Also, power is supplied from the high-voltage battery 3 and PbB5 to the second load 200 via the second system.

[0031] Next, an example of the operation of the power supply control device 1 when the power supply of the first system fails will be described using Figure 2. When the control unit 2 of the power supply control device 1 detects an overcurrent in the first system, it turns off the system switch SW1 and turns on the battery switch SW2. Note that an overcurrent is detected in the first system when the current value of the current sensor S1 is equal to or greater than a predetermined current threshold and the current value of the current sensor S2 is less than the predetermined current threshold.

[0032] As a result, in the event of a power failure in the first system, the first system can be disconnected from the second load 200 and the LiB6 can be connected to the second load 200, thereby supplying power from the LiB6 to the second load 200, thereby enabling FOP driving such as evacuation driving using the second load 200.

[0033] Next, an example of the operation of the power supply control device 1 when the power supply of the second system fails will be described using Figure 3. When the control unit 2 of the power supply control device 1 detects an overcurrent in the second system, it shuts off both the system switch SW1 and the battery switch SW2. Note that an overcurrent is detected in the second system when the current value of the current sensor S1 is equal to or greater than a predetermined current threshold and the current value of the current sensor S2 is equal to or greater than a predetermined current threshold.

[0034] As a result, in the event of a power failure in the second system, the second load 200 can be disconnected from the LiB 6, and by turning off the system switch SW1, it is possible to accurately prevent backflow from the LiB 6 to the first system. Also, by turning off the system switch SW1, power is supplied from the high-voltage battery 3 and the PbB 5 to the first load 100 and the second load 200 via the first system.

[0035] In the event of a power failure in the second system, normal driving is possible by supplying power to each of the first load 100 and the second load 200, but since power supply redundancy has been lost, it is preferable to transition to FOP driving, such as evacuation driving.

[0036] In the power supply control method according to the embodiment, the current threshold value used to detect an overcurrent from the current values ​​of the current sensors S1 and S2 is corrected according to the state of the first battery or the second battery.

[0037] That is, in the power supply control method according to the embodiment, the current threshold is corrected in accordance with the state of at least one of the high-voltage battery 3, PbB5, and LiB6. This point will be described with reference to FIG.

[0038] Fig. 4 is a diagram illustrating a method for correcting the current threshold. As shown in Fig. 4, a reference threshold is set in advance for the current threshold. The control unit 2 corrects the reference threshold by increasing or decreasing it depending on the state of the first battery or the second battery.

[0039] In the example shown in FIG. 4, the battery state includes the battery temperature, the remaining charge amount, deterioration of the battery over time, and whether or not there is an abnormality in the DC-DC converter 4.

[0040] 4, the control unit 2 corrects the reference threshold value to be higher when the battery temperature is higher than the reference temperature, and corrects the reference threshold value to be lower when the battery temperature is lower than the reference temperature. This is because the lower the battery temperature, the less current the battery can output.

[0041] 4, the control unit 2 corrects the reference threshold value to be higher when the remaining amount of stored power is greater than the reference value, and corrects the reference threshold value to be lower when the remaining amount of stored power is less than the reference value. This is because the smaller the remaining amount of stored power, the smaller the current that the battery can output.

[0042] 4, the control unit 2 corrects the reference threshold value to be higher when the battery has less deterioration over time than the standard, and corrects the reference threshold value to be lower when the battery has more deterioration over time than the standard. This is because the more deterioration over time progresses (the more deterioration there is), the less current the battery can output.

[0043] 4, the control unit 2 corrects the reference threshold value to be higher when there is no abnormality in the DC-DC converter 4, and corrects the reference threshold value to be lower when there is an abnormality in the DC-DC converter 4. This is because if the DC-DC converter 4 stops due to an abnormality, the power supply from the high-voltage battery 3 will be cut off.

[0044] In this way, the power supply control method according to the embodiment can accurately detect overcurrents due to ground faults in the first and second systems by correcting the current threshold (reference threshold) according to the state of the first or second battery. In other words, the power supply control method according to the embodiment can accurately detect system failures.

[0045] In addition, the control unit 2 can detect system failures with higher accuracy by correcting the current threshold value depending on the battery condition, such as the battery temperature, remaining charge, deterioration of the battery over time, and whether or not there is an abnormality in the DCDC converter 4.

[0046] 4 shows the case where the reference threshold is corrected by increasing or decreasing it depending on the battery state, but the current threshold may also be corrected using a model learned by machine learning, for example. Specifically, the correction value may be determined by inputting the battery state into a model obtained by performing machine learning using the battery state as an explanatory variable and a correction value from the reference threshold as a target variable.

[0047] Furthermore, the control unit 2 may apply the corrected current threshold to each of the two current sensors S1 and S2 as is, or may make the current threshold different for each of the two current sensors S1 and S2 based on the corrected current threshold.

[0048] Specifically, the control unit 2 may set the current threshold of the current sensor S2 arranged farther from the first battery (high-voltage battery 3 and PbB5) to be smaller than the current threshold of the current sensor S1 arranged closer to the first battery (high-voltage battery 3 and PbB5).

[0049] This is because when current flows from the first battery (high-voltage battery 3 and PbB5) to the second load 200, the current is shunted to the first load 100, etc., and the current value of current sensor S2 becomes smaller than the current value of current sensor S1.

[0050] It is preferable to determine how much smaller the current threshold of current sensor S2 should be than the current threshold of current sensor S1, depending on, for example, the path length between current sensor S1 and current sensor S2, and the type, number, and resistance value of resistors existing between current sensor S1 and current sensor S2.

[0051] Furthermore, the control unit 2 may measure the inrush current generated when the vehicle is started as the battery status, and correct the current threshold value according to the inrush current. Specifically, the control unit 2 measures the inrush current when an accessory power supply or the ignition key is turned on using the current sensors S1 and S2, and corrects the current threshold value to a value higher than the measured inrush current. This makes it possible to accurately avoid erroneous detection of a grid failure due to an inrush current.

[0052] The control unit 2 may correct the current threshold value based on the measurement result of a single inrush current, but may also correct the current threshold value based on the measurement results of multiple past inrush currents. In such cases, the current threshold value is corrected to a value higher than the average value of the inrush current or the maximum value of the multiple past inrush currents.

[0053] Furthermore, the control unit 2 issues simulated high-load control instructions to the loads (first load 100 and second load 200) while the vehicle is parked, measures the current values ​​flowing during the high-load control using the current sensors S1 and S2, and corrects the current threshold value according to the measured current values. Note that the high-load control refers to control in which the power consumption of the loads is equal to or greater than a predetermined value.

[0054] The control unit 2 corrects the current threshold to a value higher than the current value detected by the current sensors S1 and S2 during high load control, thereby making it possible to accurately avoid erroneous detection of a grid failure when high load control is performed in an actual driving situation.

[0055] The control unit 2 may correct the current threshold value based on the measurement results during one high-load control, but may also correct the current threshold value based on the measurement results during multiple past high-load controls. In such cases, the current threshold value is corrected to a value higher than the average value during high-load control or the maximum value during multiple past high-load controls.

[0056] Furthermore, in the above description, the control unit 2 measures the inrush current when the vehicle is started, but it is also possible to measure a pseudo inrush current even after the vehicle has been started. This point will be described with reference to FIG.

[0057] (First Modification) Fig. 5 is a diagram illustrating a power supply control device 1 according to a first modified example. As shown in Fig. 5, the power supply control device 1 according to the modified example further includes a first load switch SW3 that connects or disconnects a first load 100 from the first system, and a second load switch SW4 that connects or disconnects a second load 200 from the first system.

[0058] When the vehicle is parked, the control unit 2 connects the first load switch SW3 and the second load switch SW4 after disconnecting them, measures the current value flowing when they are connected using the current sensor S1, and corrects the current threshold value according to the measured current value.

[0059] In other words, the control unit 2 generates an inrush current by artificially creating a state at the time of vehicle startup by disconnecting the first load switch SW3 and the second load switch SW4 and then connecting them, which increases the frequency and number of times the inrush current is measured, thereby improving the accuracy of correcting the current threshold.

[0060] As described above, the power supply control device 1 according to the embodiment includes a first system, a second system, a system switch SW1, and a control unit 2. The first system includes a first battery (a high-voltage battery 3 and a PbB5) and supplies power from the first battery to a load (a first load 100 and a second load 200). The second system includes a second battery (an LiB6) and supplies power from the second battery to a load (a second load 200). The system switch SW1 connects and disconnects the first system and the second system. The control unit 2 controls the system switch SW1 to turn off when an overcurrent is detected in the first system or the second system. The control unit 2 corrects the threshold for detecting an overcurrent according to the state of the first battery or the second battery. This enables system failure to be detected with high accuracy.

[0061] In the above description, the control unit 2 detects an overcurrent as a power supply failure, but it may also detect a voltage drop as a power supply failure. That is, when a ground fault occurs as a power supply failure, an overcurrent flows toward the ground fault point, but at the same time, a sudden voltage drop occurs. Therefore, a ground fault can also be detected as a voltage drop rather than an overcurrent. This point will be explained using FIG. 6.

[0062] (Second Modification) Fig. 6 is a diagram illustrating a power supply control device 1 according to a second modification. As shown in Fig. 6, the power supply control device 1 according to the second modification has voltage sensors V1 and V2 instead of the current sensors S1 and S2 of Fig. 1. The voltage sensor V1 is provided in the first system and detects the voltage of the first system. The voltage sensor V2 is provided in the second system and detects the voltage of the second system.

[0063] When a ground fault occurs in the first or second system, the voltage detected by the voltage sensor V1 or V2 drops. The control unit 2 compares the voltage value detected by the voltage sensor V2 with a voltage threshold, and if the voltage value falls below the voltage threshold, it provisionally determines that a ground fault has occurred in the first or second system, turns off the system switch SW1, and turns on the battery switch SW2.

[0064] As a result, if a ground fault occurs in the first system, the detected voltage of the voltage sensor V1 will remain below the voltage threshold, and the detected voltage of the voltage sensor V2 will return to above the voltage threshold. After the system switch SW1 is turned off, if the detected voltage of the voltage sensor V1 remains below the voltage threshold for a predetermined time or longer and the detected voltage of the voltage sensor V2 returns to above the voltage threshold, the control unit 2 will officially determine that a ground fault has occurred in the first system and will continue to turn off the system switch SW1 and connect the battery switch SW2.

[0065] As a result, in the event of a power failure (ground fault) in the first system, the first system can be disconnected from the second load 200 and the LiB6 can be connected to the second load 200, thereby supplying power from the LiB6 to the second load 200, thereby enabling FOP driving such as evacuation driving using the second load 200.

[0066] Furthermore, if a ground fault occurs in the second system, the control unit 2 turns off the system switch SW1 and connects the battery switch SW2, and the detected voltage of the voltage sensor V2 remains below the voltage threshold and the detected voltage of the voltage sensor V1 returns to above the voltage threshold. If, after turning off the system switch SW1, the detected voltage of the voltage sensor V2 remains below the voltage threshold for a predetermined time or longer and the detected voltage of the voltage sensor V1 returns to above the voltage threshold, the control unit 2 finally determines that a ground fault has occurred in the second system and turns off the system switch SW1 and the battery switch SW2.

[0067] As a result, in the event of a power failure (ground fault) in the second system, the second load 200 can be disconnected from the LiB 6, and by turning off the system switch SW1, it is possible to accurately prevent backflow from the LiB 6 to the first system. Furthermore, by turning off the system switch SW1, power is supplied from the high-voltage battery 3 and the PbB 5 to the first load 100 and the second load 200 via the first system.

[0068] Here, in the power supply control method according to the second modification, the voltage threshold value for detecting a low voltage from the voltage values ​​of the voltage sensors V1 and V2 is corrected according to the state of the first battery or the second battery.

[0069] That is, in the power supply control method according to the second modification, the voltage threshold is corrected in accordance with the state of at least one of the high-voltage battery 3, PbB5, and LiB6. This point will be described with reference to FIG.

[0070] FIG. 7 is a diagram illustrating a method for correcting the voltage threshold. As shown in FIG. 7, a reference threshold is set in advance for the voltage threshold. The control unit 2 corrects the reference threshold by increasing or decreasing it depending on the state of the first battery or the second battery. This correction method, similar to the current threshold correction method shown in FIG. 4, uses the battery temperature, remaining charge, deterioration of the battery over time, and the presence or absence of an abnormality in the DC-DC converter 4 as the battery state, and performs the correction in the same manner as the current threshold correction method.

[0071] In this way, the power supply control method according to the second modification can accurately detect low voltages due to ground faults in the first and second systems by correcting the voltage threshold (reference threshold) according to the state of the first or second battery. In other words, the power supply control method according to the embodiment can accurately detect system failures.

[0072] In addition, the control unit 2 can detect system failures with higher accuracy by correcting the voltage threshold value depending on the battery condition, such as the battery temperature, remaining charge, deterioration of the battery over time, and whether or not there is an abnormality in the DCDC converter 4.

[0073] The control unit 2 may apply the corrected voltage threshold to each of the two voltage sensors V1 and V2 as is, or may make the voltage threshold different for each of the two voltage sensors V1 and V2 based on the corrected voltage threshold.

[0074] Specifically, the control unit 2 may set the voltage threshold of the voltage sensor V2 arranged farther away from the first battery (high-voltage battery 3 and PbB5) to be lower than the voltage threshold of the voltage sensor V1 arranged closer to the first battery (high-voltage battery 3 and PbB5).

[0075] This is because when a current flows from the first battery (high-voltage battery 3 and PbB5) to the second load 200, the voltage value of the voltage sensor V2 becomes smaller than the voltage value of the voltage sensor V1 due to loss caused by resistance.

[0076] It is preferable to determine how much lower the voltage threshold of voltage sensor V2 should be than the voltage threshold of voltage sensor V1, for example, depending on the path length between voltage sensor V1 and voltage sensor V2, and the type, number, and resistance value of the resistors existing between voltage sensor V1 and voltage sensor V2.

[0077] Furthermore, the control unit 2 may measure the amount of voltage drop that occurs when the vehicle is started as the battery state, and correct the voltage threshold value according to the amount of voltage drop that occurs when the vehicle is started. Specifically, the control unit 2 measures the amount of voltage drop that occurs when an accessory power source or the ignition key is turned on using voltage sensors V1 and V2, and corrects the voltage threshold value to a value lower than the measured amount of voltage drop. This makes it possible to accurately avoid erroneous detection of a grid failure due to a voltage drop.

[0078] The control unit 2 may correct the voltage threshold value according to the measurement result of the voltage drop amount at one startup, or may correct the voltage threshold value according to the measurement result of the voltage drop amount at multiple past startups. In such a case, the voltage threshold value is corrected to a value lower than the average voltage drop amount or the maximum voltage drop amount at multiple past startups.

[0079] Furthermore, the control unit 2 issues simulated high-load control instructions to the loads (first load 100 and second load 200) while the vehicle is parked, measures the voltage values ​​that drop during the high-load control using the voltage sensors V1 and V2, and corrects the voltage threshold value according to the measured voltage values. Note that the high-load control refers to control in which the power consumption of the loads is equal to or greater than a predetermined value.

[0080] The control unit 2 corrects the voltage threshold to a value lower than the voltage value detected by the voltage sensors V1 and V2 during high load control, thereby making it possible to accurately avoid erroneous detection of a grid failure when high load control is performed in an actual driving situation.

[0081] The control unit 2 may correct the voltage threshold value based on the measurement results during one high-load control, but may also correct the voltage threshold value based on the measurement results during multiple past high-load controls. In such cases, the voltage threshold value is corrected to a value lower than the average value during high-load control or the maximum value during multiple past high-load controls.

[0082] In the above description, the control unit 2 measures the amount of voltage drop when the vehicle is started, but it is also possible to measure a pseudo amount of voltage drop even after the vehicle is started. This point will be described with reference to FIG. 8.

[0083] (Third Modification) Fig. 8 is a diagram illustrating a power supply control device 1 according to a third modified example. As shown in Fig. 8, the power supply control device 1 according to the third modified example is configured in the same manner as in Fig. 5, except that the current sensors S1 and S2 in Fig. 5 are replaced with voltage sensors V1 and V2.

[0084] When the vehicle is parked, the control unit 2 disconnects the first load switch SW3 and the second load switch SW4 and then connects them, measures the voltage value that drops when the switches are connected using the voltage sensor V1, and corrects the voltage threshold value according to the measured voltage value.

[0085] In other words, the control unit 2 artificially creates a state at the time of vehicle startup by disconnecting the first load switch SW3 and the second load switch SW4 and then connecting them, thereby causing a voltage drop. This increases the frequency and number of times that the amount of voltage drop is measured, thereby improving the accuracy of voltage threshold correction.

[0086] (Fourth Modification) In the above description, the control unit 2 detects an overcurrent or voltage drop as a power supply failure. However, it may also detect an overvoltage as a power supply failure. The DC-DC converter 4 reduces the voltage of the high-voltage battery 3. However, if an abnormality occurs in the DC-DC converter 4, the DC-DC converter 4 may be unable to reduce the voltage and output the voltage of the high-voltage battery 3 as is, or may over-boost the voltage of the high-voltage battery 3 and output it. In other words, if the voltage of the first or second system becomes an overvoltage state equal to or greater than the overvoltage threshold, it indicates that an abnormality has occurred in the DC-DC converter 4. In this way, the fourth modification detects a power supply failure due to an abnormality in the DC-DC converter 4 by detecting an overvoltage. The configuration diagram of this fourth modification is the same as in FIG. 6, and the method of correcting the voltage threshold is the same as in FIG. 7, so detailed description will be omitted.

[0087] In variant 4, similar to the second variant described above, it is also possible to correct the voltage threshold by measuring the amount of voltage drop that occurs when the vehicle is started, and to correct the voltage threshold according to the measured value of the voltage drop due to simulated high-load control while the vehicle is parked.

[0088] In addition, in the fourth modification, the same correction of the voltage threshold as in the third modification can also be applied.

[0089] (Fifth Modification) In the above, the control unit 2 normally turns off the battery switch SW2, but as a fifth variation, the battery switch SW2 may normally be connected. In this case, power is normally supplied to the first load 100 and the second load 200 from both the first battery and the second battery, so that even if a temporary abnormality such as a power outage occurs in one of the batteries, power can be stably supplied to the first load 100 and the second load 200.

[0090] In the fifth modification, the current threshold and voltage threshold are corrected according to the state of the battery with the higher voltage between the first battery and the second battery. This also makes it possible to detect grid failures with high accuracy.

[0091] The above-described embodiments and modifications may be combined as appropriate. For example, the current sensor S1 and the voltage sensor V1 may be arranged in the first system, and the current sensor S2 and the voltage sensor V2 may be arranged in the second system.

[0092] In such a case, the control unit 2 corrects the threshold (current threshold or voltage threshold) according to the current values ​​of the current sensors S1 and S2 or the voltage values ​​of the voltage sensors V1 and V2.

[0093] Further advantages and modifications will readily occur to those skilled in the art. Therefore, 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 their equivalents. [Explanation of symbols]

[0094] 1 Power supply control device 2. Control section 3. High-voltage battery 4 DC-DC converters 5 PbB 6 LiB 7, 8 Diodes 100 1st load 200 2nd load S1, S2 current sensors SW1 System switch SW2 Battery switch SW3 First load switch SW4 Second load switch V1, V2 voltage sensors

Claims

1. a first system that supplies power from a first battery to a load; a second system that supplies power from a second battery to the load; a system switch that connects and disconnects the first system and the second system; a control unit that performs control to shut off the system switch when a voltage drop is detected in the first system or the second system; a load switch that connects and disconnects the load from the first system; Equipped with The control unit a threshold value for detecting the voltage drop is corrected according to a state of the first battery or the second battery; By connecting the load switch after disconnecting it while the vehicle is parked, the current value flowing when the load switch is connected or the voltage value of the first system or the second system is measured, and the threshold value is corrected according to the current value or the voltage value. Power control device.

2. A first system that supplies power from a first battery to a load; a second system that supplies power from a second battery to the load; a system switch that connects and disconnects the first system and the second system; a load switch that connects and disconnects the load from the first system; A power supply control method in which a control unit controls a power supply control device including: When a voltage drop is detected in the first system or the second system, the system switch is turned off; a threshold value for detecting the voltage drop is corrected according to a state of the first battery or the second battery; By connecting the load switch after disconnecting it while the vehicle is parked, the current value flowing when the load switch is connected or the voltage value of the first system or the second system is measured, and the threshold value is corrected according to the current value or the voltage value. Power control method.

3. a first system that supplies power from a first battery to a load; a second system that supplies power from a second battery to the load; a system switch that connects and disconnects the first system and the second system; a load switch that connects and disconnects the load from the first system; A control program executed by a computer that controls a power supply control device comprising: When a voltage drop is detected in the first system or the second system, the system switch is turned off; a threshold value for detecting the voltage drop is corrected according to a state of the first battery or the second battery; By connecting the load switch after disconnecting it while the vehicle is parked, the current value flowing when the load switch is connected or the voltage value of the first system or the second system is measured, and the threshold value is corrected according to the current value or the voltage value. Control program.

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