Power Switching Control System

Abstract

A power switching control system switches the power source for supplying power to a load between a first power source and a second power source in a power system. The power switching control system includes: a first switch, disposed between the first power source and the load in a power path and configured to cut off the current flowing from the second power source to the first power source in the off state of the first switch; a second switch, disposed between the second power source and the load in the power path and configured to cut off the current flowing from the first power source to the second power source in the off state of the second switch; and a control unit configured to set the second switch to an on state when the second power source is being charged.

Description

Technical Field

[0001] The present disclosure relates to a power supply switching control system. Background Art

[0002] A power supply system is known which includes a plurality of power supply systems for redundant operation, and can use another power supply system even when a part of the plurality of power supply systems malfunctions (for example, see JP-A-2019-62727 and JP-A-2004-166437). In the power supply system described in JP-A-2019-62727, a power output unit having a power supply or the like and a load are provided in each power system, and power is supplied from the power output unit to the load in each power system. Further, in the power supply system described in JP-A-2004-166437, current balance control for making currents flowing from a plurality of power supplies to a load coincide with each other is performed.

[0003] The power supply systems described in JP-A-2019-62727 and JP-A-2004-166437 are not systems in which any one of a first power supply and a second power supply connected in parallel to a common load supplies power to the common load such that the common load is redundant even when the other of the first power supply and the second power supply fails. Summary of the Invention

[0004] In view of the above circumstances, an object of the present disclosure is to provide a power supply switching control system in which any one of a first power supply and a second power supply connected in parallel to a common load supplies power to the common load such that the common load can be redundant and a standby second power supply can be reliably charged.

[0005] An aspect of a non-limiting embodiment of the present disclosure relates to providing a power supply switching control system configured to switch a power supply for supplying power to a load between a first power supply and a second power supply in a power supply system including the first power supply and the second power supply connected in parallel with the load, and wherein the first power supply, the second power supply, and the load are connected in order of the first power supply, the load, and the second power supply from one side of a power supply unit through a power path, the power supply switching control system including: a first switch which is a MOSFET provided between a connection point of the first power supply in the power path and a connection point of the load and is configured to cut off a current flowing from a side of the second power supply to a side of the first power supply in a turned-off state of the first switch; a second switch which is a MOSFET provided between a connection point of the second power supply in the power path and a connection point of the load and is configured to cut off a current flowing from a side of the first power supply to a side of the second power supply in a turned-off state of the second switch; and a control unit configured to set the second switch to an on state when the second power supply is being charged.

[0006] According to the present disclosure, any one of a first power supply and a second power supply connected in parallel to a common load supplies power to the common load, so that the common load can be redundant, and the second power supply for standby can be reliably charged. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1 is a diagram showing a vehicle-mounted power supply system including a power supply switching control system according to an embodiment of the present disclosure.

[0008] Figure 2 is a diagram showing when Figure 1 a ground fault occurs on the main battery side with respect to the first switch in the vehicle-mounted power supply system shown.

[0009] Figure 3 is a diagram showing a vehicle-mounted power supply system including a power supply switching control system according to another embodiment of the present disclosure.

[0010] Figure 4 is a diagram showing a vehicle-mounted power supply system including a power supply switching control system according to another embodiment of the present disclosure.

[0011] Figure 5 is a diagram showing Figure 4 a flowchart of a process of fault search control of the power supply switching control system shown.

[0012] Figure 6 is a diagram showing when Figure 4 a fault occurs between the first switch and the second switch in the vehicle-mounted power supply system shown.

[0013] Figure 7 is a diagram showing when Figure 4 a fault occurs between the first switch and the second switch in the vehicle-mounted power supply system shown.

[0014] Figure 8 is a diagram showing when Figure 4 a fault occurs between the first switch and the second switch in the vehicle-mounted power supply system shown.

[0015] Figure 9 is a diagram showing when Figure 4 a fault occurs between the first switch and the second switch in the vehicle-mounted power supply system shown.

[0016] Figure 10 is a diagram showing when Figure 4 a fault occurs between the first switch and the second switch in the vehicle-mounted power supply system shown. DETAILED DESCRIPTION

[0017] In the following, the present disclosure will be described based on preferred embodiments. The present disclosure is not limited to the embodiments described below, and the embodiments described below can be appropriately modified without departing from the gist of the present disclosure. Further, in the embodiments described below, although illustrations and descriptions of a part of the configuration are omitted, needless to say, known or well-known techniques are appropriately applied to the details of the techniques omitted within a range not conflicting with the content described below.

[0018] Figure 1 is a diagram showing a vehicle-mounted power supply system 1 including a power supply switching control system 10 according to an embodiment of the present disclosure. As Figure 1 shown, the vehicle-mounted power supply system 1 includes a main battery 2, a sub-battery 3, a power supply unit 4, and a power supply switching control system 10. In the vehicle-mounted power supply system 1 of the present embodiment, the main battery 2 and the sub-battery 3 are connected in parallel to a load L via a diode or circuit 11. Normally, power is supplied from the main battery 2 to the load l. When a failure occurs on the main battery 2 side, power is supplied from the sub-battery 3 to the load l.

[0019] In the vehicle-mounted power supply system 1 of the present embodiment, the main battery 2 is a conventional power supply with a rated voltage of 12V, and the sub-battery 3 is an emergency power supply with a rated voltage of 12V. The negative terminals of the main battery 2 and the sub-battery 3 are connected to the vehicle body ground via a ground cable EC. At least one of the main battery 2 and the sub-battery 3 can be replaced with another power supply such as a capacitor.

[0020] The power supply unit 4 includes a high-voltage (HV) power supply 5 such as 48V and a DC / DC converter 6. The power supply 5 outputs high-voltage power to the DC / DC converter 6. The DC / DC converter 6 steps down the high-voltage power output from the power supply 5 and outputs the stepped-down power to the diode or circuit 11 of the power supply switching control system 10.

[0021] The power supply switching control system 10 includes a diode or circuit 11 and a control device 20. The diode or circuit 11 includes a first switch 12, a second switch 13, a first protection fuse 14, a second protection fuse 15, and a third protection fuse 16. The first switch 12 and the second switch 13 are N-channel metal oxide semiconductor field effect transistors (MOSFETs). The source S of the first switch 12 and the output terminal of the DC / DC converter 6 are connected via a first wiring H1, and the drain D of the first switch 12 and the drain D of the second switch 13 are connected via a second wiring H2. Further, the source S of the second switch 13 and the positive terminal of the sub-battery 3 are connected via a third wiring H3. The second protection fuse 15 is provided in the third wiring H3. The connection point between the terminal end of the third wiring H3 and the positive terminal of the sub-battery 3 is referred to as a connection point P3.

[0022] The first protection fuse 14 is provided in the fourth wiring H4 branched from the connection point P1 of the first wiring H1. The output terminal of the DC / DC converter 6 and the source S of the first switch 12 are connected to the positive terminal of the main battery 2 through the first protection fuse 14. In addition, the third protection fuse 16 is provided in the fifth wiring H5 branched from the connection point P2 of the second wiring H2. The drain D of the first switch 12 and the drain D of the second switch 13 are connected to the load L through the third protection fuse 16.

[0023] The main battery 2, the sub-battery 3, and the load L are connected to the power path EL including the first wiring H1, the second wiring H2, and the third wiring H3 in the order of the main battery 2, the load L, and the sub-battery 3 from the power supply unit 4 side. In addition, the first switch 12 is provided between the connection point P1 and the connection point P2 of the power path EL, and the second switch 13 is provided between the connection point P2 and the connection point P3 of the power path EL.

[0024] The first switch 12 and the second switch 13, which are N-channel MOSFETs, cut off the current from the drain D to the source S in the off state. The first switch 12 in the off state cuts off the current from the sub-battery 3 side to the main battery 2 side. In addition, the second switch 13 in the off state cuts off the current from the main battery 2 side to the sub-battery 3 side.

[0025] Here, the first switch 12 and the second switch 13 are in the on state to allow the current to flow from the drain D to the source S by applying a gate voltage from the drivers 21 and 22 described later. In addition, even in a state where no gate voltage is applied from the drivers 21 and 22, when the voltage on the source S side is higher than the voltage on the drain D side, the first switch 12 and the second switch 13 are in the on state, and the current flows from the source S to the drain D. On the other hand, when no gate voltage is applied from the drivers 21 and 22 and the voltage on the drain D side is higher than the voltage on the source S side, the first switch 12 and the second switch 13 are in the off state, and the current from the drain D to the source S is cut off. In the following description, the state in which the first switch 12 and the second switch 13 are turned on by applying a gate voltage from the drivers 21 and 22 is referred to as a forced on state. On the other hand, when no gate voltage is applied from the drivers 21 and 22, the state in which the first switch 12 and the second switch 13 are turned on is referred to as an on state. In addition, when no gate voltage is applied from the drivers 21 and 22, the state in which the first switch 12 and the second switch 13 are turned off is referred to as an off state.

[0026] When the voltage on the source S side of the first switch 12 is higher than the voltage on the drain D side of the first switch 12, the first switch 12 is in the on state, and current flows from the main battery 2 side to the load L side and the secondary battery 3 side. On the other hand, when the voltage on the drain D side of the first switch 12 is higher than the voltage on the source S side of the first switch 12, the first switch 12 is in the off state to cut off the current from the main battery 2 side to the load L side and the secondary battery 3 side.

[0027] When the voltage on the source S side of the second switch 13 is higher than the voltage on the drain D side of the second switch 13, the second switch 13 is in the on state, and current flows from the secondary battery 3 side to the load L side and the main battery 2 side. On the other hand, when the voltage on the drain D side of the second switch 13 is higher than the voltage on the source S side of the second switch 13, the second switch 13 is in the off state to cut off the current from the secondary battery 3 side to the load L side and the main battery 2 side.

[0028] The control device 20 includes drivers 21 and 22 and a microprocessing unit (MPU) 23. The driver 21 is a gate drive circuit including resistors, capacitors, etc., and in response to a control signal output from the MPU 23, switches the gate drive voltage applied to the first switch 12 to a voltage that can be set to a forced on state or a voltage that can be set to an on state and an off state. In addition, the driver 22 is a gate drive circuit including resistors, capacitors, etc., and in response to a control signal output from the MPU 23, switches the gate drive voltage applied to the second switch 13 to a voltage that can be set to a forced on state or a voltage that can be set to an on state and an off state.

[0029] The MPU 23 outputs control signals to the drivers 21 and 22 to switch the forced on state / on or off state of the first switch 12 and the second switch 13 according to on / off commands from the in-vehicle electronic control unit (ECU) 7. Usually, the MPU 23 supplies power from the power supply unit 4 or the main battery 2 to the load L by setting the first switch 12 to the forced on state and setting the second switch 13 to the on or off state. When supplying power from the power supply unit 4 or the main battery 2 to the load L, it is not necessary to set the first switch 12 in the forced on state with a gate voltage applied. Even when the first switch 12 is in the on state without a gate voltage applied, power can be supplied from the power supply unit 4 or the main battery 2 to the load l.

[0030] On the other hand, when the secondary battery 3 is being charged, the MPU 23 sets the first switch 12 and the second switch 13 in the forced on state. When charging the secondary battery 3, it is not necessary to set the first switch 12 in the forced on state with a gate voltage applied. Even when the first switch 12 is in the on state without a gate voltage applied, power can be supplied from the power supply unit 4 or the main battery 2 to the secondary battery 3.

[0031] Figure 2 This is a diagram showing the functions when Figure 1 a ground fault occurs on the main battery 2 side with respect to the first switch 12 in the in - vehicle power supply system 1 shown in the figure. As Figure 2 shown, when a ground fault occurs on the main battery 2 side (power supply unit 4 side) with respect to the first switch 12, the voltage on the source S side of the first switch 12 is lower than the voltage on the drain D side of the first switch 12. In this case, when the first switch 12 is in the off state, the first switch 12 cuts off the bidirectional current. On the other hand, the voltage on the source S side of the second switch 13 is higher than the voltage on the drain D side of the second switch 13. Therefore, the second switch 13 is in the on state, and the current flows from the secondary battery 3 side to the load L side. At this time, since the first switch 12 cuts off the bidirectional current, no current flows from the secondary battery 3 to the main battery 2, and power is supplied from the secondary battery 3 to the load L.

[0032] Although not shown in the figure, when a ground fault occurs on the secondary battery 3 side with respect to the second switch 13, the voltage on the source S side of the second switch 13 is lower than the voltage on the drain D side of the second switch 13. In this case, when the second switch 13 is in the off state, the second switch 13 cuts off the bidirectional current. On the other hand, the voltage on the source S side of the first switch 12 is higher than the voltage on the drain D side of the first switch 12. Therefore, the first switch 12 is in the on state, and the current flows from the main battery 2 side to the load L side. At this time, since the second switch 13 cuts off the bidirectional current, no current flows from the power supply unit 4 or the main battery 2 to the secondary battery 3, and power is supplied from the power supply unit 4 or the main battery 2 to the load L.

[0033] As described above, in the power - switching control system 10 of this embodiment, the main battery 2 and the secondary battery 3 are connected to the common load L via a diode or circuit 11 including the first switch 12 and the second switch 13 which are MOSFETs. Therefore, even when a ground fault occurs on the main battery 2 side or the secondary battery 3 side and any one of the first switch 12 and the second switch 13 is in the off state, power can be supplied to the load L from the battery (or power supply unit 4) where no ground fault has occurred.

[0034] In addition, when the main battery 2, the sub-battery 3, and the load L are connected to the power path EL from the power supply unit 4 side in the order of the main battery 2, the load L, and the sub-battery 3, the first switch 12 between the main battery 2 and the load L is set to the ON state or the forced-ON state, and the second switch 13 between the load L and the sub-battery 3 is set to the forced-ON state, so that the sub-battery 3 can be charged by supplying power from the power supply unit 4 or the main battery 2 to the sub-battery 3. In addition, when supplying power to the normal load L, the first switch 12 is set to the ON state or the forced-ON state, and the second switch 13 is set to the OFF state, so that power can be supplied from the power supply unit 4 or the main battery 2 to the load L.

[0035] The source S of the first switch 12, which is an N-channel MOSFET, is connected to the main battery 2 and the power supply unit 4. The drain D of the second switch 13, which is also an N-channel MOSFET, and the drain D of the first switch 12 are connected to each other and connected to the load L. In addition, the source S of the second switch 13 is connected to the sub-battery 3. Therefore, when a ground fault occurs on the source S side (main battery 2 side or power supply unit 4 side) of the first switch 12, the voltage on the source S side of the first switch 12 is lower than the voltage on the drain D side of the first switch 12, so that the first switch 12 is in the OFF state. Therefore, the current from the sub-battery 3 side to the main battery 2 side can be cut off, and power can be supplied from the sub-battery 3 to the load L. On the other hand, when a ground fault occurs on the source S side (sub-battery 3 side) of the second switch 13, the voltage on the source S side of the second switch 13 is lower than the voltage on the drain D side of the second switch 13, so that the second switch 13 is in the OFF state. Therefore, the current from the main battery 2 side or the power supply unit 4 side to the sub-battery 3 side can be cut off, and power can be supplied from the main battery 2 or the power supply unit 4 to the load L.

[0036] Figure 3 FIG. is a diagram showing a vehicle-mounted power supply system 101 including a power supply switching control system 110 according to another embodiment of the present disclosure. The same reference numerals are given to configurations similar to those of the above-described embodiment, and the description of the above-described embodiment is incorporated.

[0037] As Figure 3 shown, the vehicle-mounted power supply system 101 of the present embodiment includes a plurality of switch units 112 and a plurality of loads L connected in parallel to the power path EL. Each of the plurality of switch units 112 includes a first switch 12 and a second switch 13. In addition, a load L is provided for each switch unit 112. Each of the plurality of loads L is connected to the second wiring H2 through the fifth wiring H5, and the second wiring connects the drain D of the first switch 12 and the drain D of the second switch 13 to each other. The illustration of the drivers 21 and 22 (see Figure 1 ) is omitted.

[0038] As in the above-described embodiment, in the power supply switching control system 110 of the present embodiment, the main battery 2 and the sub-battery 3 are connected to the common load L via a diode or circuit 111 including a first switch 12 and a second switch 13 that are MOSFETs. In the power supply switching control system 110 of the present embodiment, a plurality of diode or circuits 111 extending from the main battery 2 and the sub-battery 3 to the load L are provided in parallel. Therefore, even when a ground fault occurs on the main battery 2 side or the sub-battery 3 side and any one of the plurality of first switches 12 and the plurality of second switches 13 is in the off state, power can be supplied to the plurality of loads L from the battery (or power supply unit 4) in which no ground fault has occurred.

[0039] Further, when the main battery 2, the sub-battery 3, and the load L are connected to the power supply path EL in the order of the main battery 2, the load L, and the sub-battery 3 from the power supply unit 4 side, the plurality of first switches 12 are set in the on state or the forced on state, and the plurality of second switches 13 are set in the forced on state so that the sub-battery 3 can be charged by supplying power from the power supply unit 4 or the main battery 2 to the sub-battery 3. Further, when power is supplied to the normal load L, the plurality of first switches 12 are set in the on state or the forced on state, and the plurality of second switches 13 are set in the off state, so that power can be supplied to the plurality of loads L from the power supply unit 4 or the main battery 2.

[0040] Here, in the power supply switching control system 110 of the present embodiment, a first wiring H1 connects the plurality of first switches 12 to the main battery 2 and the power supply unit 4, and a third wiring H3 connects the plurality of second switches 13 to the sub-battery 3. When the first wiring H1 fails, power can be supplied to the plurality of loads L from the sub-battery 3 through the third wiring H3, and when the third wiring H3 fails, power can be supplied to the plurality of loads L from the main battery 2 or the power supply unit 4 through the first wiring H1.

[0041] Figure 4 FIG. is a diagram showing a vehicle-mounted power supply system 201 including a power supply switching control system 210 according to another embodiment of the present disclosure. The same reference numerals are given to configurations similar to those of the above-described embodiment, and the description of the above-described embodiment is incorporated.

[0042] As Figure 4 shown, in the vehicle-mounted power supply system 201 of the present embodiment, a plurality of loads L1, L2, L3, and L4 are connected in parallel to the power supply path EL. Further, the power supply switching control system 210 according to the present embodiment includes a first switch 12 and a second switch 13 provided in the power supply path EL, and first to third switch units 211, 212, and 213 provided between the first switch 12 and the second switch 13 in the power supply path EL.

[0043] A plurality of loads L1, L2, L3, and L4 are provided from the power supply unit 4 side in the order of load L1, load L2, load L3, and load L4. The first switch 12 is provided between the connection point P1 of the main battery 2 and the connection point P4 of the load L1 on the power supply path EL. The second switch 13 is provided between the connection point P7 of the load L4 and the connection point P3 of the secondary battery 3 on the power supply path EL.

[0044] The first to third switch units 211, 212, and 213 are provided from the power supply unit 4 side in the order of the first switch unit 211, the second switch unit 212, and the third switch unit 213. The first switch unit 211 is provided between the connection point P4 of the load L1 on the power supply path EL and the connection point P5 of the load L2. The second switch unit 212 is provided between the connection point P5 of the load L2 on the power supply path EL and the connection point P6 of the load L3. The third switch unit 213 is provided between the connection point P6 of the load L3 on the power supply path EL and the connection point P7 of the load L4.

[0045] The first to third switch units 211, 212, and 213 each include a third switch 214 and a fourth switch 215. The third switch 214 and the fourth switch 215 are N-channel MOSFETs. The source S of the third switch 214 and the source S of the fourth switch 215 are connected to each other, and the drain D of the third switch 214 is connected to the loads L1 to L3 on the power supply unit 4 side with respect to the drain D of the third switch 214. The drain D of the third switch 214 of the first switch unit 211 is also connected to the drain D of the first switch 12.

[0046] The drain D of the fourth switch 215 is connected to the loads L2 to L4 on the secondary battery 3 side with respect to the drain D of the fourth switch 215. The drain D of the fourth switch 215 of the third switch unit 213 is also connected to the drain D of the second switch 13.

[0047] The control device 220 includes drivers 21 and 22 for the first switch 12 and the second switch 13 (see Figure 1 ), drivers (not shown) for the first to third switch units 211 to 213, and an MPU 223. The drivers for the first to third switch units 211 to 213 are gate drive circuits including resistors, capacitors, etc., and in response to a control signal output from the MPU 223, switch the gate drive voltage applied to the third switch 214 and the fourth switch 215 to a voltage that can be set to a forced-on state or a voltage that can be set to an on or off state.

[0048] Normally, the MPU 223 sets the first switch 12, the third switch 214, and the fourth switch 215 to the forced-on state, and sets the second switch 13 to the off state, thereby supplying power from the power supply unit 4 or the main battery 2 to the plurality of loads L1 to L4. On the other hand, when the secondary battery 3 is being charged, the MPU 223 sets the first switch 12, the second switch 13, the third switch 214, and the fourth switch 215 to the forced-on state.

[0049] Here, in the power supply switching control system 210 of the present embodiment, when a fault such as a ground fault occurs between the first switch 12 and the second switch 13, a fault search control for detecting the fault occurrence position is executed. Hereinafter, the fault search control will be described.

[0050] Figure 5 is a flowchart showing Figure 4 the processing of the fault search control of the power supply switching control system 210 shown. In addition, Figures 6 to 10 is a diagram showing Figure 4 the functions when a fault occurs between the first switch 12 and the second switch 13 in the in-vehicle power supply system 201 shown.

[0051] As Figure 5 shown in the flowchart, in step 1, the MPU 223 determines whether the voltage V main of the main battery 2 and the voltage V sub of the secondary battery 3 are equal to or lower than a predetermined value (for example, 6V) that is lower than the value during normal times. When an affirmative determination is made in step 1, the process proceeds to step 2, and when a negative determination is made in step 1, step 1 is repeatedly executed.

[0052] In step 2, the MPU 223 sets the second switch unit 212 located in the middle of the first to third switch units 211 to 213 to the off state. Therefore, for example, as Figure 6 and 8 shown, when a fault such as a ground fault occurs between the second switch unit 212 and the main battery 2, the voltage of the second switch unit 212 on the main battery 2 side is in a reduced state, while the voltage of the second switch unit 212 on the secondary battery 3 side returns to 12V. Then, power is supplied from the secondary battery 3 to the loads L3 and L4 between the second switch unit 212 and the secondary battery 3.

[0053] As Figure 5 shown, the process proceeds from step 2 to step 3. In step 3, the MPU 223 determines whether the voltage of the second switch unit 212 on the main battery 2 side is lower than the voltage of the second switch unit 212 on the secondary battery 3 side. When an affirmative determination is made in step 3, the process proceeds to step 4, and when a negative determination is made in step 3, the process proceeds to step 7.

[0054] In step 4, the MPU 223 sets the first switch unit 211, which is the closest to the main battery 2 side among the first to third switch units 211 to 213, to the off state. Therefore, for example, as Figure 7 shown, when a fault such as a ground fault occurs between the first switch unit 211 and the second switch unit 212, the voltage of the first switch unit 211 on the secondary battery 3 side is in a reduced state, while the voltage of the first switch unit 211 on the main battery 2 side returns to 12V. Then, power is supplied from the main battery 2 or the power supply unit 4 to the load L1 between the first switch 12 and the first switch unit 211. In addition, for example, as Figure 9 shown, when a fault such as a ground fault occurs between the first switch unit 211 and the first switch 12, the voltages of the first switch unit 211 on the main battery 2 side and the secondary battery 3 side are in a state of being reduced to a low voltage (for example, 6V or lower).

[0055] As Figure 5 shown, the process transfers from step 4 to step 5. In step 5, the MPU 223 determines whether the voltage of the first switch unit 211 on the main battery 2 side returns to 12V, and whether the voltage of the first switch unit 211 on the secondary battery 3 side is equal to or lower than a predetermined value lower than 12V (for example, 6V). When an affirmative determination is made in step 5, the process of the fault search control ends, and when a negative determination is made in step 5, the process transfers to step 6.

[0056] In step 6, the MPU 223 keeps the first switch unit 211 in the off state, sets the first switch 12 in the off state, and sets the second switch unit 212 in the forced on state. Therefore, for example, as Figure 10 shown, when a fault such as a ground fault occurs between the first switch unit 211 and the first switch 12, the voltage of the first switch unit 211 on the main battery 2 side is in a state of being reduced to a low voltage, while the voltage of the first switch unit 211 on the secondary battery 3 side returns to 12V. Then, power is supplied from the secondary battery 3 to the loads L2 to L4 except for the load L1 closest to the main battery 2 side. After the process of step 6 is executed, the process of the fault search control ends.

[0057] In step 7 which is transferred from step 3, the MPU 223 sets the third switch unit 213, which is the closest to the secondary battery 3 side among the first to third switch units 211 to 213, to the off state. Thus, for example, when a fault occurs between the second switch unit 212 and the third switch unit 213, the voltage of the first switch unit 211 on the secondary battery 3 side is in a state of being reduced to a low voltage (e.g., 6V or lower), while the voltage of the first switch unit 212 on the main battery 2 side returns to 12V. Then, power is supplied from the secondary battery 3 to the load L4 between the second switch 13 and the third switch unit 213. Additionally, for example, when a fault occurs between the third switch unit 213 and the second switch 13, the voltages of the third switch unit 213 on the main battery 2 side and the secondary battery 3 side are in a state of being reduced to a low voltage.

[0058] The process transfers from step 7 to step 8. In step 8, the MPU 223 determines whether the voltage of the third switch unit 213 on the secondary battery 3 side has returned to 12V, and whether the voltage of the third switch unit 213 on the main battery 2 side is equal to or lower than a predetermined value lower than 12V (e.g., 6V). When an affirmative determination is made in step 8, the process of the fault search control ends, and when a negative determination is made in step 8, the process transfers to step 9.

[0059] In step 9, the MPU 223 keeps the third switch unit 213 in the off state, sets the second switch 13 in the off state, and sets the second switch unit 212 in the forced-on state. Thus, for example, when a fault occurs between the third switch unit 213 and the second switch 13, the voltage of the third switch unit 213 on the secondary battery 3 side is in a reduced state, while the voltage of the third switch unit 213 on the main battery 2 side returns to 12V. Then, power is supplied from the main battery 2 to the loads L1 to L3 except for the load L4 closest to the secondary battery 3 side. After performing the process of step 9, the process of the fault search control ends.

[0060] As described above, according to the power supply switching control system 210 of the present embodiment, when a fault occurs between the first switch 12 and the second switch 13, power can be supplied from the main battery 2 or at least one of the power supply unit 4 and the secondary battery 3 to the remaining loads except for any one of the multiple loads L1 to L4.

[0061] Although the present disclosure has been described above based on the embodiments, the present disclosure is not limited to the above embodiments, and the above embodiments can be modified or known or publicly known technologies can be appropriately combined as long as the gist of the present disclosure does not deviate.

[0062] For example, in the above-described embodiment, the first switch 12 and the second switch 13 of the MOSFET are N-channel MOSFETs, but the first switch 12 and the second switch 13 may be P-channel MOSFETs. In this case, the positional relationship between the source S and the drain D may be opposite to the positional relationship of the above-described embodiment. In addition, it is not essential that the first to third switch units 211 to 213 are configured with MOSFETs, and the MOSFETs may be replaced with other semiconductor switches.

[0063] In addition, although the high-voltage power supply 5 and the DC / DC converter 6 are provided as the power supply unit 4 in the above-described embodiment, for example, an alternator may be provided as the power supply unit 4, and a voltage conversion unit for stepping down the high-voltage power, such as a DC / DC converter, may not be provided.

[0064] Here, the features of the above-described embodiment of the power supply switching control system according to the present disclosure will be briefly summarized and listed in the following [1] to [6].

[0065] [1] A power supply switching control system configured to switch a power supply for supplying power to a load (L, L1-L4) between a first power supply (2) and a second power supply (3) in a power supply system (1), the power supply system including the first power supply (2) and the second power supply (3) connected in parallel with the load (L, L1-L4), and in the power supply system, the first power supply (2), the second power supply (3), and the load (L, L1-L4) are connected in the order of the first power supply (2), the load (L, L1-L4), and the second power supply (3) from one side of the power supply unit (4) through a power path (EL), the power supply switching control system including:

[0066] A first switch (12), which is a MOSFET provided between a connection point (P1) of the first power supply (2) and a connection point (P2) of the load (L, L1-L4) in the power path (EL), and is configured to cut off a current flowing from the side of the second power supply (3) to the side of the first power supply (2) in a turned-off state of the first switch (12);

[0067] A second switch (13), which is a MOSFET provided between a connection point (P3) of the second power supply (3) and a connection point (P2) of the load (L, L1-L4) in the power path (EL), and is configured to cut off a current flowing from the side of the first power supply (2) to the side of the second power supply (3) in a turned-off state of the second switch (13); and

[0068] A control unit (20, 220), configured to set the second switch (13) in an on state when the second power supply (3) is being charged.

[0069] [2]The power supply switching control system according to [1] above,

[0070] wherein the first switch (12) and the second switch (13) are N-channel MOSFETs; and

[0071] wherein the source (S) of the first switch (12) is connected to the first power supply (2) and the power supply unit (4), the drain (D) of the first switch (12) and the drain (D) of the second switch (13) are connected to each other and connected to the load (L, L1-L4), and the source (S) of the second switch (13) and the second power supply (3) are connected to each other.

[0072] [3]The power supply switching control system according to [1] or [2] above,

[0073] wherein when power is supplied to the load (L, L1-L4) from at least one of the power supply unit (4) and the first power supply (2), the control unit (20, 220) sets the first switch (12) to the on state and sets the second switch (13) to the off state.

[0074] [4]The power supply switching control system according to any one of [1] to [3] above, further comprising:

[0075] a plurality of switch units (112) connected in parallel to the power supply path (EL),

[0076] wherein each of the plurality of switch units (112) includes a first switch (12) and a second switch (13), and each of the plurality of loads (L) is connected between the first switch (12) and the second switch (13) of each of the plurality of switch units (112).

[0077] [5]The power supply switching control system according to any one of [1] to [3] above, further comprising:

[0078] a plurality of third switches (211, 212, 213) connected in series to the power supply path (E1) and arranged between the first switch (12) and the second switch (13),

[0079] wherein each third switch (211, 212, 213) cuts off the bidirectional current flowing through it in its off state; and

[0080] wherein each of the plurality of loads (L1-L4) is connected between the first switch (12) and one of the third switches (211, 212, 213) in the power supply path (E1), between the second switch (13) and another one of the third switches (211, 212, 213), and between the third switches (211, 212, 213).

[0081] [6]According to the power supply switching control system described in [5] above,

[0082] wherein the control unit (220) sets any one of a plurality of third switches (211, 212, 213) to an off state, sets the other third switches (211, 212, 213), the first switch (12), and the second switch (13) to an on state, and compares a first voltage (V1) between any one of the plurality of third switches (211, 212, 213) and the first power supply (2) with a second voltage (V2) between any one of the plurality of third switches and the second power supply (3);

[0083] wherein when the first voltage (V1) is lower than the second voltage (V2), the control unit (220) sets the third switch between any one of the plurality of third switches (211, 212, 213) and the first switch (12) to an off state, and further when the first voltage (V1) and the second voltage (V2) are predetermined low voltages, the control unit (220) sets the first switch (12) to an off state and sets any one of the plurality of third switches (211, 212, 212) from an off state to an on state; and

[0084] wherein when the second voltage (V2) is higher than the first voltage (V1), the control unit (220) sets the third switch between any one of the plurality of third switches (211, 212, 213) and the second switch (13) to an off state, and further when the first voltage (V1) and the second voltage (V2) are predetermined low voltages, the control unit (220) sets the second switch (13) to an off state and sets any one of the plurality of third switches (211, 212, 212) from an off state to an on state.

Claims

1. A power supply switching control system configured to switch a power supply for supplying power to a load between a first power supply and a second power supply in a power supply system. The power supply system includes the first power supply and the second power supply connected in parallel with the load, and wherein the first power supply, the second power supply, and the load are connected through a power path in the order of the first power supply, the load, and the second power supply from one side of a power supply unit. The power supply switching control system includes: A first switch, which is a MOSFET disposed between a connection point of the first power supply and a connection point of the load in the power path, and is configured to cut off a current flowing from one side of the second power supply to one side of the first power supply in an off state of the first switch; A second switch, which is a MOSFET disposed between a connection point of the second power supply and a connection point of the load in the power path, and is configured to cut off a current flowing from one side of the first power supply to one side of the second power supply in an off state of the second switch; A control unit configured to set the second switch to an on state when the second power supply is being charged; And A plurality of third switches connected in series to the power path and arranged between the first switch and the second switch, wherein each of the third switches cuts off a bidirectional current flowing through it in its off state; and wherein each of the plurality of loads is connected in the power path between the first switch and one of the third switches, between the second switch and another of the third switches, and between the third switches.

2. The power supply switching control system according to claim 1, Among them, the first switch and the second switch are N-channel MOSFETs; and wherein the source of the first switch is connected to the first power supply and the power supply unit, the drains of the first switch and the second switch are connected to each other and connected to the load, and the source of the second switch and the second power supply are connected to each other.

3. The power supply switching control system according to claim 1 or 2, Among them, when supplying power to the load from at least one of the power supply unit and the first power supply, the control unit sets the first switch to an on state and sets the second switch to an off state.

4. The power supply switching control system according to claim 1 or 2, further comprising: A plurality of switch units connected in parallel to the power path, wherein each of the plurality of switch units includes the first switch and the second switch, and each of the plurality of loads is connected between the first switch and the second switch of each of the plurality of switch units.

5. The power supply switching control system according to claim 1 or 2, Among them, The control unit sets any one of the plurality of third switches to an off state, sets the other third switches, the first switch, and the second switch to an on state, and compares a first voltage V1 between any one of the plurality of third switches and the first power supply with a second voltage V2 between any one of the plurality of third switches and the second power supply; Wherein, when the first voltage V1 is lower than the second voltage V2, the control unit sets the third switch between any one of the plurality of third switches and the first switch to an off state, and further when the first voltage V1 and the second voltage V2 are predetermined low voltages, the control unit sets the first switch to an off state and sets any one of the plurality of third switches from an off state to an on state; and Wherein, when the second voltage V2 is higher than the first voltage V1, the control unit sets the third switch between any one of the plurality of third switches and the second switch to an off state, and further when the first voltage V1 and the second voltage V2 are predetermined low voltages, the control unit sets the second switch to an off state and sets any one of the plurality of third switches from an off state to an on state.

Images