Power supply system, power supply system control program

Abstract

To appropriately control a power supply relay in a power supply system capable of controlling electrical connection / disconnection between a power supply and a storage battery by controlling the on / off of the power supply relay.SOLUTION: A power supply system 10 includes: power supply relays RL1, RL2 that are provided between a power supply and a power storage battery; first and second voltage monitor circuits 21, 22 that detect voltages on opposite sides of the power supply relays; a relay control unit 43 that switches the power supply relay to an on state on a condition that a voltage difference between a first voltage and a second voltage respectively obtained from the first and second voltage monitor circuits when the power supply relay is in an off state is equal to or less than a predetermined on-voltage difference; a switching circuit that switches to an equi-potential connection state in which high / low potential sides of the first and second voltage monitor circuits are connected to each other when the power storage battery and the power supply are disconnected; and a correction unit 41 that corrects at least one of the first and second voltages on the basis of the voltage difference between the voltages detected by the first and second voltage monitor circuits in the equi-potential connection state.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a power supply system including a power supply relay provided between a power supply and a storage battery, and a control program for the power supply system. [Background technology]

[0002] A power supply system is known that connects an external power supply source and an on-board storage battery via an external terminal on the vehicle, and charges and discharges the on-board storage battery. In the power supply system disclosed in Patent Document 1, a protection circuit including a power supply relay is provided between the on-board storage battery and the external terminal. When the power supply relay is controlled to an on state, the on-board storage battery and the external power supply are electrically connected, enabling charging and discharging of each other. When the power supply relay is controlled to an off state, the electrical connection between the on-board storage battery and the external power supply is cut off. The protection circuit monitors the voltage on the storage battery side and the voltage on the power supply side of the power supply relay using separate voltage measurement units, and performs on / off control of the power supply relay based on the difference between the voltages, i.e., the voltage difference between both ends. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-54164 Summary of the Invention [Problem to be solved by the invention]

[0004] Errors in the voltage monitoring values ​​by each voltage measurement unit affect errors in the voltage difference between both ends of the power relay. If the error in the voltage difference between both ends of the power relay is large, the power relay may be inappropriately controlled to be on or off. For example, if the voltage difference between both ends of the power relay exceeds the withstand voltage (e.g., maximum allowable voltage) of the power relay and the power relay is mistakenly controlled to be on, the power relay may fail. In particular, when multiple voltage measurement units are provided, there is a concern that errors in the voltage monitoring values ​​of each voltage measurement unit may accumulate, increasing the possibility that the power relay may be inappropriately controlled to be on or off.

[0005] In view of the above, an object of the present invention is to provide a technology for appropriately controlling a power supply relay in a power supply system that can control electrical connection / disconnection between a power supply and a storage battery by controlling the on / off of the power supply relay. [Means for solving the problem]

[0006] The present invention provides a power supply system including: a power supply relay provided in each of a high potential path and a low potential path between a power supply and a storage battery; a first voltage monitor circuit that detects, as a first voltage, a voltage between the high potential path and the low potential path on the power supply side or the storage battery side of the power supply relay; a second voltage monitor circuit that detects, as a second voltage, a voltage between the high potential path and the low potential path on the opposite side of the power supply relay from the first voltage monitor circuit; and a relay control unit that switches the power supply relay to an on state on condition that a voltage difference between the first voltage and the second voltage detected by each voltage monitor circuit when the power supply relay is off is equal to or less than a predetermined on-voltage difference. This power supply system further includes a switching circuit for switching, with the storage battery and the power supply disconnected, a state in which the high potential side and low potential side of the first voltage monitor circuit are connected to the same potential as the high potential side and low potential side of the second voltage monitor circuit, respectively, and a correction unit that, with the switching circuit in the same potential connection state, performs a correction process to correct at least one of the first voltage and the second voltage based on the voltage difference between the voltages detected by the first voltage monitor circuit and the second voltage monitor circuit.

[0007] In the power supply system according to the present invention, a power relay is provided in each of the high-potential path and the low-potential path between the power supply and the storage battery. A first voltage monitor circuit is provided on either the power supply side or the storage battery side of the power relay, and a second voltage monitor circuit is provided on the other side. When the power relay is in an off state (i.e., when the power supply and the storage battery are not connected), the relay control unit switches the power relay to an on state under the condition that the voltage difference between the first voltage detected by the first voltage monitor circuit and the second voltage detected by the second voltage monitor circuit (i.e., the voltage difference across the power relay detected by each monitor circuit) is equal to or less than a predetermined on-voltage difference. For example, by setting the predetermined on-voltage difference to a value that does not exceed the allowable voltage when the power relay transitions to on, on-off control that avoids failure of the power relay is possible. If the detected voltages obtained from each voltage monitor circuit contain an error, it becomes difficult to appropriately switch the power relay to the on state. However, the power supply system according to the present invention further includes a switching circuit that can switch the power supply system to an equal-potential connection state in which the high-potential side and low-potential side of the first voltage monitor circuit are connected to the high-potential side and low-potential side of the second voltage monitor circuit, respectively, while the storage battery and the power supply are disconnected. When the equal-potential connection state is established by the switching circuit, the correction unit executes a correction process to correct at least one of the first voltage and the second voltage based on the voltage difference between the voltages detected by each voltage monitor circuit. In the equal-potential connection state, the first monitor circuit and the second monitor circuit are connected to the same potential. For example, by correcting the voltage difference between the voltages detected by each voltage monitor circuit to zero, an error (hereinafter referred to as a relative error) contained in the voltage difference between the first voltage and the second voltage relative to the voltage difference between the detection points where the voltages are detected by each voltage monitor circuit can be corrected. The correction unit also corrects the relative error contained in the first voltage and the second voltage acquired while the power supply relay is off, allowing the relay control unit to appropriately switch the power supply relay to the on state. That is, in a power supply system in which electrical connection / disconnection between a power supply and a storage battery can be controlled by on / off control of a power supply relay, it is possible to appropriately control the power supply relay.

[0008] The present invention can also be provided as a control program for controlling the above-described power supply system. The control program causes a computer to execute a correction step of correcting at least one of the first voltage and the second voltage based on a voltage difference between the voltages detected by the first voltage monitor circuit and the second voltage monitor circuit while the switching circuit is in the same potential connection state, and a relay control step of switching the power supply relay to an on state on condition that the voltage difference between the first voltage and the second voltage obtained from each voltage monitor circuit in a state in which the power supply relay is off is equal to or smaller than a predetermined on-voltage difference. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a diagram showing a power supply system according to a first embodiment. [Figure 2] 2 is a diagram showing a power supply circuit and a switching circuit of the power supply system shown in FIG. 1. [Figure 3] 3 is a control flowchart of the power supply system according to the first embodiment. [Figure 4] FIG. 10 is a diagram showing a power supply circuit and a switching circuit of a power supply system according to a modified example. [Figure 5] FIG. 10 is a diagram showing a power supply system according to a second embodiment. [Figure 6] FIG. 10 is a diagram showing a power supply system according to a modified example. [Figure 7] 10 is a control flowchart of a power supply system according to a second embodiment. [Figure 8] FIG. 10 is a diagram showing a power supply system according to a modified example. [Figure 9] FIG. 10 is a diagram showing a power supply system according to a modified example. DETAILED DESCRIPTION OF THE INVENTION

[0010] (First embodiment) 1 is mounted on a vehicle and includes a storage battery 12, an on-board circuit 20, a control device 40, a high potential terminal 26H, and a low potential terminal 26L. The power supply system 10 and the power supply 11 can be connected by connecting the power supply 11 outside the vehicle to the high potential terminal 26H and the low potential terminal 26L. The power supply 11 and the storage battery 12 are connected via the on-board circuit 20.

[0011] The in-vehicle circuit 20 includes a first power supply relay RL1, a second power supply relay RL2, a first voltage monitor circuit 21, a second voltage monitor circuit 22, and first to fourth switches SW1 to SW4.

[0012] The first power supply relay RL1 is provided on a high potential path between the power supply 11 and the storage battery 12, and the second power supply relay RL2 is provided on a low potential path between the power supply 11 and the storage battery 12. When the first power supply relay RL1 and the second power supply relay RL2 are both in the on state, the power supply 11 and the storage battery 12 are connected to each other, and charging and discharging can be performed between the power supply 11 and the storage battery 12.

[0013] The first voltage monitor circuit 21 is connected to the high potential path and the low potential path at nodes n1 and n2, which are on the power supply 11 side of the first power supply relay RL1 and the second power supply relay RL2, respectively. The first voltage monitor circuit 21 and node n1 are connected to each other by a wiring 23H, and the first voltage monitor circuit 21 and node n2 are connected to each other by a wiring 23L. The first voltage monitor circuit 21 is connected to the high potential path and the low potential path at nodes n3 and n4, which are on the storage battery 12 side of the first power supply relay RL1 and the second power supply relay RL2, respectively. The first voltage monitor circuit 21 and node n3 are connected to each other by a wiring 24H, and the first voltage monitor circuit 21 and node n4 are connected to each other by a wiring 24L. The wiring 24H is connected to the wiring 23H at node n5, and the wiring 24L is connected to the wiring 23L at node n6. The wiring 23H and 23L correspond to a power supply side bypass path provided on the power supply 11 side with respect to the first power supply relay RL1 and the second power supply relay RL2. The wiring 24H and 24L correspond to a storage battery side bypass path provided on the storage battery 12 side with respect to the first power supply relay RL1 and the second power supply relay RL2.

[0014] The first switch SW1 is provided between nodes n1 and n5 on the wiring 23H. The second switch SW2 is provided between nodes n2 and n6 on the wiring 23L. The third switch SW3 is provided on the wiring 24H. The fourth switch SW4 is provided on the wiring 24L. In this embodiment, the first to fourth switches SW1 to SW4 are semiconductor switching elements, and more specifically, MOSFETs, IGBTs, etc. can be exemplified, but they may also be switches that mechanically switch on and off.

[0015] Fig. 2 shows an example of control of the first to fourth switches SW1 to SW4. As shown in Fig. 2(a), when the first switch SW1 and the second switch SW2 are in the off state and the third switch SW3 and the fourth switch SW4 are in the on state, the first voltage monitor circuit 21 can detect the voltage between the node n3 and the node n4. In the state of Fig. 2(a), the first voltage monitor circuit 21 detects the voltage between the high potential path and the low potential path on the storage battery 12 side of the first power supply relay RL1 and the second power supply relay RL2.

[0016] 2(b), when the first switch SW1 and the second switch SW2 are in the on state and the third switch SW3 and the fourth switch SW4 are in the off state, the voltage between the node n1 and the node n2 can be detected by the first voltage monitor circuit 21. In the state of FIG. 2(b), the first voltage monitor circuit 21 detects the voltage between the high potential path and the low potential path on the power supply 11 side of the first power supply relay RL1 and the second power supply relay RL2.

[0017] The second voltage monitor circuit 22 is connected to the high potential path and the low potential path at nodes n7 and n8, which are on the storage battery 12 side with respect to the first power supply relay RL1 and the second power supply relay RL2, respectively. The nodes n7 and n8 are located on the storage battery 12 side. The second voltage monitor circuit 22 and the node n7 are connected to each other by a wiring 25H, and the second voltage monitor circuit 22 and the node n8 are connected to each other by a wiring 25L. The wiring 25H and 25L correspond to battery-side bypass paths provided on the storage battery 12 side with respect to the first power supply relay RL1 and the second power supply relay RL2.

[0018] 1 and 2, regardless of the on / off states of the first to fourth switches SW1 to SW4, the second voltage monitor circuit 22 can detect the voltage between the node n7 and the node n8. The second voltage monitor circuit 22 detects the voltage between the high potential path and the low potential path on the storage battery 12 side of the first power supply relay RL1 and the second power supply relay RL2. In the state of FIG. 2(b), the high potential side and the low potential side of the first voltage monitor circuit 21 are connected to the same potential as the high potential side and the low potential side of the second voltage monitor circuit 22, respectively, and both the first voltage monitor circuit 21 and the second voltage monitor circuit 22 detect the voltage between the high potential path and the low potential path on the storage battery 12 side of the first power supply relay RL1 and the second power supply relay RL2.

[0019] The control device 40 includes a correction unit 41, a switch (SW) control unit 42, and a relay (RL) control unit 43. The control device 40 is primarily configured with a well-known microcomputer (MCU) including a CPU, ROM, RAM, flash memory, and the like. For example, the CPU executes a power conversion program installed in the ROM to realize the functions of the correction unit 41, the SW control unit 42, the RL control unit 43, and the like. The functions provided by the MCU may be provided by software stored in a physical memory device and a computer that executes the software, software alone, hardware alone, or a combination thereof. For example, when the MCU is implemented by a hardware electronic circuit, the function may be provided by a digital circuit including multiple logic circuits or an analog circuit. For example, the MCU executes a program stored in a non-transitory physical recording medium that serves as a memory unit. The program includes, for example, a battery control processing program described below. Execution of the program results in the execution of a method corresponding to the program. The memory unit is, for example, a non-volatile memory. Note that the program stored in the memory unit can be updated, for example, via a network such as the Internet.

[0020] The control device 40 stores a first voltage monitor map showing the relationship between the output acquired from the first voltage monitor circuit 21 and the detected voltage. The control device 40 stores a second voltage monitor map showing the relationship between the output acquired from the second voltage monitor circuit 22 and the detected voltage. The control device 40 refers to the first voltage monitor map and the second voltage monitor map based on the outputs acquired from the first voltage monitor circuit 21 and the second voltage monitor circuit 22, and acquires the respective detected voltages. Hereinafter, in this specification, the voltages acquired by the control device 40 by referring to the respective voltage monitor maps based on the outputs acquired from the respective voltage monitor circuits 21 and 22 are referred to as detected voltages. The control device 40 controls the on / off of the first to fourth switches SW1 to SW4 and the first and second power supply relays RL1 and RL2.

[0021] The SW control unit 42 operates the first to fourth switches SW1 to SW4 and controls the gate drive signals of the first to fourth switches SW1 to SW4 to perform on / off control of the first to fourth switches SW1 to SW4. As shown in FIG. 2(a), when the SW control unit 42 controls the first switch SW1 and the second switch SW2 to an off state and the third switch SW3 and the fourth switch SW4 to an on state, the first voltage monitor circuit 21 can detect the voltage between the node n3 and the node n4. As shown in FIG. 2(b), when the SW control unit 42 controls the first switch SW1 and the second switch SW2 to an on state and the third switch SW3 and the fourth switch SW4 to an off state, the first voltage monitor circuit 21 can detect the voltage between the node n1 and the node n2. The first and second switches SW1 and SW2 correspond to control switches provided between the first voltage monitor circuit 21 and the high and low potential paths on the opposite side of the first and second power supply relays RL1 and RL2 from the second voltage monitor circuit 22. The third and fourth switches SW3 and SW4 correspond to correction switches provided between the first voltage monitor circuit 21 and the high and low potential paths on the same side of the first and second power supply relays RL1 and RL2 as the second voltage monitor circuit 22.

[0022] The RL control unit 43 controls the connection state between the power supply 11 and the storage battery 12 by performing on / off control on the first power supply relay RL1 and the second power supply relay RL2 as the operation targets. When the RL control unit 43 controls the first power supply relay RL1 and the second power supply relay RL2 to an on state, the power supply 11 and the storage battery 12 are connected to each other, and charging and discharging can be performed between the power supply 11 and the storage battery 12. When the RL control unit 43 controls the first power supply relay RL1 and the second power supply relay RL2 to an off state, the power supply 11 and the storage battery 12 are disconnected from each other, and charging and discharging are not performed between the power supply 11 and the storage battery 12.

[0023] When the difference between the voltage of the power supply 11 and the voltage of the storage battery 12 is large, if the first power supply relay RL1 and the second power supply relay RL2 are switched from the off state to the on state, a voltage exceeding the allowable voltage when each of the first power supply relay RL1 and the second power supply relay RL2 transitions to the on state may be applied to the first power supply relay RL1 and the second power supply relay RL2, which may cause the first power supply relay RL1 and the second power supply relay RL2 to malfunction.

[0024] Therefore, the RL control unit 43 acquires the voltage difference between both ends of the first power relay RL1 and the second power relay RL2 while controlling the first power relay RL1 and the second power relay RL2 to the off state, and executes a relay control process to switch the first power relay RL1 and the second power relay RL2 from the off state to the on state based on this voltage difference between both ends.

[0025] Specifically, the RL control unit 43 controls the first power relay RL1 and the second power relay RL2 to the OFF state, and the SW control unit 42 controls the first switch SW1 and the second switch SW2 to the ON state and the third switch SW3 and the fourth switch SW4 to the OFF state as shown in FIG. 2(b). In this state, the control device 40 obtains a first voltage as a detected voltage from the first voltage monitor circuit 21 and a second voltage as a detected voltage from the second voltage monitor circuit. The relay control unit 43 calculates the voltage difference between the first voltage and the second voltage and switches the first power relay RL1 and the second power relay RL2 to the ON state if this voltage difference is equal to or less than a predetermined ON voltage difference. For example, by setting the ON voltage difference to a value that does not exceed the allowable voltage when the first power relay RL1 and the second power relay RL2 transition to ON, ON / OFF control that avoids failure of the first power relay RL1 and the second power relay RL2 is possible. The first and second power supply relays RL1, RL2 and the first and second voltage monitor circuits 21, 22 function as a power supply circuit that switches between connection and disconnection between the power supply 11 and the storage battery 12.

[0026] If the first and second voltages acquired from the first and second voltage monitor circuits 21 and 22 contain errors, the voltage difference between the first and second voltages calculated by the relay control unit 43 may also contain errors. In this case, it becomes difficult to avoid failures in the first power relay RL1 and the second power relay RL2 and properly switch them on. In this embodiment, the error contained in the voltage difference between the first and second voltages is an error contained in the voltage difference between the first and second voltages (the difference between the detected voltages) relative to the voltage difference (the actual voltage difference) between the first detection point (nodes n1 and n2 in this embodiment) where the first voltage monitor circuit 21 detects the first voltage and the second detection point (nodes n7 and n8 in this embodiment) where the second voltage monitor circuit 22 detects the second voltage. Such an error contained in the voltage difference between the first and second voltages relative to the voltage difference between the first and second detection points where the first and second voltage monitor circuits detect the first and second voltages, respectively, is referred to as a relative error.

[0027] The control device 40 includes a correction unit 41, which corrects the relative error contained in each of the detected voltages obtained from the first and second voltage monitor circuits 21, 22. The correction unit 41 eliminates or reduces the relative error contained in the voltage difference (more specifically, the difference in the detected voltages) between the first voltage and the second voltage calculated by the relay control unit 43, so that the RL control unit 43 can more reliably avoid failure of the first power relay RL1 and the second power relay RL2 and switch them to the on state appropriately.

[0028] 2(a) (referred to as an equipotential connection state), the control device 40 acquires each detected voltage based on the output from the first voltage monitor circuit 21 and the second voltage monitor circuit 22. With the first and second power supply relays RL1 and RL2 in an off state, the first power supply relay RL1 and the second power supply relay RL2 are controlled to an off state, and the SW control unit 42 controls the first switch SW1 and the second switch SW2 to an off state and the third switch SW3 and the fourth switch SW4 to an on state, as shown in FIG. 2(a) (referred to as an equipotential connection state), the control device 40 acquires each detected voltage based on the output from the first voltage monitor circuit 21 and the second voltage monitor circuit 22. With the first and second power supply relays RL1 and RL2 in an off state, the storage battery 12 and the power supply 11 are disconnected from each other, the first to fourth switches SW1 to SW4 function as a switching circuit configured to be switchable to an equipotential connection state in which the high potential side and the low potential side of the first voltage monitor circuit 21 are connected to the high potential side and the low potential side of the second voltage monitor circuit 22, respectively.

[0029] In this same-potential connection state, the high-potential side and low-potential side of the first voltage monitor circuit 21 are connected to the same potential as the high-potential side and low-potential side of the second voltage monitor circuit 22, respectively, and both the first voltage monitor circuit 21 and the second voltage monitor circuit 22 detect the voltage between the high-potential path and the low-potential path on the storage battery 12 side of the first power supply relay RL1 and the second power supply relay RL2. That is, in an ideal state where there is no error in the first voltage monitor circuit 21 and the second voltage monitor circuit 22, the detected voltages obtained from the first voltage monitor circuit 21 and the second voltage monitor circuit 22 in the same-potential connection state will be equal, and the voltage difference between the detected voltages will be zero.

[0030] The correction unit 41 calculates the voltage difference between the detected voltages obtained from the first voltage monitor circuit 21 and the second voltage monitor circuit 22 in the same potential connection state, and corrects at least one of the first voltage and the second voltage based on this voltage difference. More specifically, the correction unit 41 executes a correction process to correct the relationship between the output and the detected voltage for at least one of the first voltage monitor map and the second voltage monitor map.

[0031] More specifically, the correction unit 41 may be configured to correct the relationship between the output and the detected voltage for at least one of the first voltage monitor map and the second voltage monitor map so that the voltage difference between the detected voltages obtained from the first voltage monitor circuit 21 and the second voltage monitor circuit 22 in the same potential connection state is equal to or less than a predetermined threshold, i.e., a correction voltage difference. In this case, the correction voltage difference may be set to zero. Furthermore, for example, the correction unit 41 may be configured to perform the correction by using the voltage difference between the detected voltages obtained from the first voltage monitor circuit 21 and the second voltage monitor circuit 22 in the same potential connection state as a correction amount, for example, by adding the correction amount to one of the first voltage and the second voltage.

[0032] The control device 40 may be configured to execute the correction process by the correction unit 41 every time the relay control process is executed by the RL control unit 43, or may be configured to execute the correction process not every time but at a predetermined interval or after each execution of the relay control process.

[0033] Fig. 3 is a control flowchart of power supply system 10 executed by control device 40. The processing shown in the flowchart of Fig. 3 is realized by a CPU constituting control device 40 executing a control program for power supply system 10 installed in ROM, and is repeatedly executed at predetermined intervals when power supply system 10 is connected to power supply 11.

[0034] In step S101, the first and second power supply relays RL1 and RL2 are controlled to the OFF state, the first and second switches SW1 and SW2 are controlled to the OFF state, and the third and fourth switches SW3 and SW4 are controlled to the ON state. That is, the first and second power supply relays RL1 and RL2 and the first to fourth switches SW1 to SW4 are controlled to be in the same potential connection state. Then, the process proceeds to step S102.

[0035] In step S102, detected voltages are acquired from the first voltage monitor circuit 21 and the second voltage monitor circuit 22. The detected voltages acquired from the first voltage monitor circuit 21 and the second voltage monitor circuit 22 in step S102 are detected voltages acquired in an equipotential connection state. More specifically, the detected voltage acquired from the first voltage monitor circuit 21 is a detected voltage acquired in a state in which the high-potential side and the low-potential side of the first voltage monitor circuit 21 are connected to the same potential as the high-potential side and the low-potential side of the second voltage monitor circuit 22, respectively. This voltage is referred to as V12. The detected voltage acquired from the second voltage monitor circuit 22 is a detected voltage between the high-potential path and the low-potential path on the storage battery 12 side of the first and second power supply relays RL1 and RL2. This detected voltage is referred to as V22. Then, the process proceeds to step S103.

[0036] In step S103, at least one of the first voltage monitor map and the second voltage monitor map is corrected so that the difference between V12 and V22 is equal to or less than a predetermined threshold, a corrected voltage difference. For example, the first voltage monitor map is corrected so that abs(V12-V22), which is the absolute value of the difference between V12 and V22, becomes zero. By performing the correction steps shown in steps S101 to S103, it is possible to correct the detected voltages acquired from the first voltage monitor circuit 21 and the second voltage monitor circuit 22 in the same potential connection state so that they do not deviate from each other. Then, the process proceeds to step S104.

[0037] In step S104, the first and second switches SW1 and SW2 are switched to the on state, and the third and fourth switches SW3 and SW4 are switched to the off state. The first and second power relays RL1 and RL2 are not switched and remain in the off state. Then, the process proceeds to step S105.

[0038] In step S105, detection voltages are acquired from the first voltage monitor circuit 21 and the second voltage monitor circuit 22, respectively. In step S105, the detection voltage acquired from the first voltage monitor circuit 21 is the detection voltage between the high-potential path and the low-potential path on the power supply 11 side with respect to the first and second power relays RL1 and RL2, and this detection voltage is referred to as V11. The detection voltage acquired from the second voltage monitor circuit 22 is, as in step S102, the detection voltage (V22) between the high-potential path and the low-potential path on the battery 12 side with respect to the first and second power relays RL1 and RL2. V11 corresponds to the first voltage, and V22 corresponds to the second voltage. Then, the process proceeds to step S106.

[0039] In step S108, it is determined whether the absolute value of the difference between the first voltage V11 and the second voltage V22, abs(V11 - V22), is less than the on-possible voltage difference Xth1, which is a predetermined threshold value. The on-possible voltage difference Xth1 is set to a value that does not exceed the allowable voltage when the first and second power relays RL1 and RL2 transition to the on state. If abs(V11 - V22) < Xth1, the process proceeds to step S109. If abs(V11 - V22) ≥ Xth1, the process proceeds to step S111.

[0040] In step S109, it is determined that charging from the power supply 11 to the battery 12 is "possible", and the process proceeds to step S110. In step S110, the first and second power relays RL1 and RL2 are switched from the off state to the on state, and the process ends. On the other hand, in step S111, it is determined that charging from the power supply 11 to the battery 12 is "impossible", and the process ends. By the relay control steps shown in steps S10-4 to S111, on-off control that avoids failures of the first and second power relays RL1 and RL2 becomes possible.

[0041] As described above, according to the control program for power supply system 10 executed by control device 40 and the control method for power supply system 10 implemented thereby, the correction step shown in steps S101 to S103 can correct the detected voltage obtained from first voltage monitor circuit 21 and the detected voltage obtained from second voltage monitor circuit 22 in the same potential connection state so that they do not differ. After the correction step is executed, the relay control step shown in steps S104 to S111 is executed, so that on / off control can be performed more reliably while avoiding failure of first and second power supply relays RL1 and RL2. In a state where the relative error between the detected voltages obtained from the first voltage monitor circuit 21 and the second voltage monitor circuit 22 in the same potential connection state is eliminated, the first voltage V11 and the second voltage V22 are obtained, and it is determined whether the voltage difference between both ends of the first and second power supply relays RL1 and RL2 (the difference between V11 and V12) does not exceed the allowable voltage when the first and second power supply relays RL1 and RL2 transition to the on state, and it is then determined whether to switch the first and second power supply relays RL1 and RL2 to the on state, thereby enabling more reliable on / off control that avoids failure of the first and second power supply relays RL1 and RL2. As a result, it becomes possible to appropriately control the first and second power supply relays RL1 and RL2 in the power supply system 10 that can control the electrical connection / disconnection between the power supply source 11 and the storage battery 12 by on / off control of the first and second power supply relays RL1 and RL2.

[0042] (Variation) As in the onboard circuit 30 shown in FIG. 4 , the second voltage monitor circuit may be a second voltage monitor circuit 32 connected to the high-potential path and the low-potential path at nodes n9 and n10, which are on the power supply 11 side of the first power supply relay RL1 and the second power supply relay RL2, respectively. The second voltage monitor circuit 32 and node n9 are connected to each other by a wiring 35H, and the second voltage monitor circuit 32 and node n10 are connected to each other by a wiring 35L. In this case, the same-potential connection state corresponds to a state in which the RL control unit 43 controls the first power supply relay RL1 and the second power supply relay RL2 to an off state, the SW control unit 42 controls the first switch SW1 and the second switch SW2 to an on state, and the third switch SW3 and the fourth switch SW4 to an off state. In the correction step, correction processing is performed based on the voltage difference between the detected voltages obtained from the first voltage monitor circuit 21 and the second voltage monitor circuit 22 in this same-potential connection state. In the relay control step executed after the correction step, the first power relay RL1 and the second power relay RL2 remain in the off state, the first switch SW1 and the second switch SW2 are switched to the off state, and the third switch SW3 and the fourth switch SW4 are switched to the on state, and based on the first voltage and the second voltage obtained, it is determined whether or not to switch the first and second power relays RL1 and RL2 to the on state.

[0043] (Second embodiment) The power supply system according to the second embodiment shown in Fig. 5 includes an on-board power supply system 110 and an external circuit 130. The power supply system 110 is mounted on the vehicle and includes a storage battery 112, an on-board circuit 120, a control device 140, a high potential terminal 126H, and a low potential terminal 126L. By connecting an external power supply 111 to the high potential terminal 126H and the low potential terminal 126L, the power supply system 110 and the power supply 112 can be connected via the external circuit 130. The power supply 111 and the storage battery 112 are connected via the on-board circuit 120 and the external circuit 130.

[0044] The on-board circuit 120 includes a first power supply relay RL11, a second power supply relay RL12, a first voltage monitor circuit 121, and a second voltage monitor circuit 122. The external circuit 130 includes a first auxiliary power supply relay RL13 and a second auxiliary power supply relay RL14.

[0045] The first power supply relay RL11 is provided in the high potential path between the power supply 111 and the storage battery 112, and the second power supply relay RL12 is provided in the low potential path between the power supply 111 and the storage battery 112. The first auxiliary power supply relay RL13 is provided in the high potential path between the power supply 111 and the first voltage monitor circuit 121, and the second auxiliary power supply relay RL14 is provided in the low potential path between the power supply 111 and the first voltage monitor circuit 121. The first and second auxiliary power supply relays RL13 and RL14 are provided in the high potential path and the low potential path, respectively, on the power supply 11 side of the power supply circuit including the first and second power supply relays RL11 and RL12 and the first voltage monitor circuit 121 and the second voltage monitor circuit 122. When the first and second power supply relays RL11, RL12 and the first and second auxiliary power supply relays RL13, RL14 are all in the on state, the power supply 111 and the storage battery 112 are connected to each other, and charging and discharging can be performed between the power supply 111 and the storage battery 112.

[0046] The first voltage monitor circuit 121 is connected to the high potential path and the low potential path at nodes n11 and n12, which are on the power supply 111 side of the first power supply relay RL11 and the second power supply relay RL12, respectively. The first voltage monitor circuit 121 and node n11 are connected to each other by wiring 123H, and the first voltage monitor circuit 21 and node n12 are connected to each other by wiring 123L. The wiring 123H and 123L correspond to power supply-side bypass paths provided on the power supply 111 side of the first power supply relay RL11 and the second power supply relay RL12.

[0047] The second voltage monitor circuit 122 is connected to the high potential path and the low potential path at nodes n15 and n16, which are on the storage battery 112 side of the first power supply relay RL11 and the second power supply relay RL12, respectively. The second voltage monitor circuit 122 and node n15 are connected to each other by wiring 125H, and the second voltage monitor circuit 122 and node n16 are connected to each other by wiring 25L. The wiring 125H and 125L correspond to battery-side bypass paths provided on the storage battery 112 side of the first power supply relay RL11 and the second power supply relay RL12.

[0048] The control device 140 includes a correction unit 141 and a relay (RL) control unit 143. Like the control device 40, the control device 140 is mainly configured with a well-known microcomputer (mCU) including a CPU, a ROM, a RAM, a flash memory, etc., and, for example, the CPU executes a power conversion program installed in the ROM to realize the functions of the correction unit 141, the RL control unit 143, etc., included in the control device 140.

[0049] Like the control device 40, the control device 140 stores first and second voltage monitor maps that indicate the relationship between the outputs obtained from the first and second voltage monitor circuits 121, 122 and the detected voltages. The control device 140 obtains the detected voltages from the first and second voltage monitor circuits 121, 122. The control device 140 controls the on / off of the first and second power supply relays RL11, RL12. When the exterior circuit 130 and the power supply system 110 are connected, the control device 140 can also control the on / off of the first and second auxiliary power supply relays RL13, RL14.

[0050] The RL control unit 143 performs on / off control on the first and second power supply relays RL11, RL12 and the first and second auxiliary power supply relays RL13, RL14 as the operation targets, thereby switching between connecting the high potential side and low potential side of the first voltage monitor circuit 121 to the same potential as the high potential side and low potential side of the second voltage monitor circuit 122 or connecting them to the power supply 111 side, and controlling the connection state between the power supply 111 and the storage battery 112.

[0051] When the RL control unit 143 controls the first and second power supply relays RL11, RL12 and the first and second auxiliary power supply relays RL13, RL14 to the on state, the power supply 111 and the storage battery 112 are connected to each other, and charging and discharging can be performed between the power supply 111 and the storage battery 112.

[0052] When the RL control unit 143 controls the first and second power supply relays RL11, RL12 to the on state and the first and second auxiliary power supply relays RL13, RL14 to the off state, the power supply 111 and the storage battery 112 are disconnected from each other, and the high potential side and low potential side of the first voltage monitor circuit 121 are connected to the same potential as the high potential side and low potential side of the second voltage monitor circuit 122. This state corresponds to an equal potential connection state in which the storage battery 112 and the power supply 111 are disconnected and the high potential side and low potential side of the first voltage monitor circuit 121 are connected to the same potential as the high potential side and low potential side of the second voltage monitor circuit 122, respectively.

[0053] When the RL control unit 143 controls the first and second power supply relays RL11 and RL12 to an OFF state and controls the first and second auxiliary power supply relays RL13 and RL14 to an ON state, the power supply 111 and the storage battery 112 are disconnected from each other, and the high potential side and low potential side of the first voltage monitor circuit 121 are connected to the power supply 111 side. This state is called a relay-on determination state. In the relay-on determination state, the detected voltage obtained from the first voltage monitor circuit 121 is the first voltage, and the detected voltage obtained from the second voltage monitor circuit 122 is the second voltage.

[0054] The RL control unit 143 controls the first and second power supply relays RL11 and RL12 and the first and second auxiliary power supply relays RL13 and RL14 to be in a relay-on determination state, acquires a voltage difference (voltage difference between the first voltage and the second voltage) across the first power supply relay RL11 and the second power supply relay RL12, and executes relay control processing to switch the first power supply relay RL11 and the second power supply relay RL12 from an OFF state to an ON state based on this voltage difference. In this embodiment, the relative error is an error included in the voltage difference between the first voltage and the second voltage (difference in detected voltages) relative to the voltage difference (actual voltage difference) between a first detection point (nodes n11 and n12 in this embodiment) where the first voltage monitor circuit 121 detects the first voltage and a second detection point (nodes n15 and n16 in this embodiment) where the second voltage monitor circuit 122 detects the second voltage.

[0055] Correction unit 141 acquires detected voltages from first voltage monitor circuit 121 and second voltage monitor circuit 122 in a state in which RL control unit 143 controls first and second power supply relays RL11 and RL12 and first and second auxiliary power supply relays RL13 and RL14 to be in an equal-potential connection state. In this equal-potential connection state, the high-potential side and low-potential side of first voltage monitor circuit 121 are connected to the same potential as the high-potential side and low-potential side of second voltage monitor circuit 122, respectively, and both first voltage monitor circuit 121 and second voltage monitor circuit 122 detect the voltage between the high-potential path and low-potential path connected to storage battery 12. That is, in an ideal state in which first voltage monitor circuit 121 and second voltage monitor circuit 122 have no error whatsoever, the detected voltages acquired from first voltage monitor circuit 121 and second voltage monitor circuit 122 in the equal-potential connection state are equal, and the voltage difference between the detected voltages is zero.

[0056] The correction unit 141 calculates the voltage difference between the detected voltages obtained from the first voltage monitor circuit 121 and the second voltage monitor circuit 122 in the same potential connection state, and corrects at least one of the first voltage and the second voltage based on this voltage difference. More specifically, the correction unit 141 executes a correction process to correct the relationship between the output and the detected voltage for at least one of the first voltage monitor map and the second voltage monitor map.

[0057] As in the first embodiment, the correction unit 141 may be configured to correct the relationship between the output and the detected voltage for at least one of the first and second voltage monitor maps so that the voltage difference between the detected voltages acquired from the first and second voltage monitor circuits 121 and 122 in the same potential connection state is equal to or less than a predetermined threshold, i.e., a correction voltage difference. In this case, the correction voltage difference may be set to zero. Furthermore, for example, the correction unit 141 may be configured to perform the correction by adding the voltage difference between the detected voltages acquired from the first and second voltage monitor circuits 121 and 122 in the same potential connection state as a correction amount to one of the first voltage and the second voltage. Furthermore, the control device 140 may be configured to perform the correction process by the correction unit 141 every time the relay control process is executed by the RL control unit 143. Alternatively, the correction process may be performed not every time but at a predetermined interval or every time the relay control process is executed.

[0058] The first and second auxiliary power supply relays RL13 and RL14 may be configured to be indirectly controlled by the RL control unit 143. For example, as shown in Fig. 6, an exterior RL control unit 133 that transmits control signals to the first and second auxiliary power supply relays RL13 and RL14 may be provided outside the vehicle, and when the control device 140 and the exterior RL control unit 133 are able to communicate with each other, the exterior RL control unit 133 may control the first and second auxiliary power supply relays RL13 and RL14 in response to instructions from the RL control unit 143. The exterior RL control unit 133 may be provided in the power feeding equipment together with the power feeding power source 111 and the exterior circuit 130, for example.

[0059] Fig. 7 is a control flowchart of the power supply system 110 executed by the control device 140. The processing shown in the flowchart of Fig. 7 is realized by the CPU constituting the control device 140 executing a control program for the power supply system 110 installed in the ROM, and is repeatedly executed at predetermined intervals when the power supply system 110 is connected to the power supply 111.

[0060] In step S301, the first and second power supply relays RL11 and RL12 are controlled to be in the ON state, and the first and second auxiliary power supply relays RL13 and RL14 are controlled to be in the OFF state. That is, the first and second power supply relays RL11 and RL12 and the first and second auxiliary power supply relays RL13 and RL14 are controlled to be in the same potential connection state. Then, the process proceeds to step S302.

[0061] In step S302, detected voltages are acquired from the first voltage monitor circuit 121 and the second voltage monitor circuit 122. The detected voltages acquired from the first voltage monitor circuit 121 and the second voltage monitor circuit 122 in step S302 are detected voltages acquired in an equipotential connection state. More specifically, the detected voltage acquired from the first voltage monitor circuit 121 is a detected voltage acquired in a state in which the high-potential side and the low-potential side of the first voltage monitor circuit 121 are connected to the same potential as the high-potential side and the low-potential side of the second voltage monitor circuit 122, respectively. This detected voltage is referred to as V13. The detected voltage acquired from the second voltage monitor circuit 122 is a voltage between the high-potential path and the low-potential path on the storage battery 112 side of the first and second power supply relays RL11 and RL12. This voltage is referred to as V23. Then, the process proceeds to step S303.

[0062] In step S303, at least one of the first voltage monitor map and the second voltage monitor map is corrected so that the difference between V13 and V23 is equal to or less than a predetermined threshold, a corrected voltage difference. For example, the first voltage monitor map is corrected so that abs(V13-V23), which is the absolute value of the difference between V13 and V23, becomes zero. By performing the correction steps shown in steps S301 to S303, it is possible to correct the detected voltages acquired from the first voltage monitor circuit 121 and the second voltage monitor circuit 122 in the same potential connection state so that they do not deviate from each other. Then, the process proceeds to step S304.

[0063] In step S304, the first and second power supply relays RL11 and RL12 are switched to the OFF state, and the first and second auxiliary power supply relays RL13 and RL14 are switched to the ON state, after which the process proceeds to step S305.

[0064] In step S305, detected voltages are obtained from the first voltage monitor circuit 121 and the second voltage monitor circuit 122. In step S305, the detected voltage obtained from the first voltage monitor circuit 121 is the detected voltage between the high potential path and the low potential path on the power supply 11 side of the first and second power supply relays RL1 and RL2, and this detected voltage is referred to as V14. As in step S302, the detected voltage obtained from the second voltage monitor circuit 122 is the detected voltage between the high potential path and the low potential path on the storage battery 12 side of the first and second power supply relays RL1 and RL2, and this detected voltage is referred to as V24. V14 corresponds to the first voltage, and V24 corresponds to the second voltage. Then, the process proceeds to step S308.

[0065] In step S308, it is determined whether the absolute value of the difference between the first voltage V14 and the second voltage V24, abs(V14 - V24), is less than the on - enable voltage difference Xth3 which is a predetermined threshold value. The on - enable voltage difference Xth3 is set to a value that does not exceed the allowable voltage when transitioning to the on state of the first and second power relays RL11 and RL12. If abs(V14 - V24) < Xth3, the process proceeds to step S309. If abs(V14 - V24) ≥ Xth3, the process proceeds to step S311.

[0066] In step S309, it is determined that the charging from the power supply 111 to the storage battery 112 is "enabled", and the process proceeds to step S310. In step S310, the first and second power relays RL11 and RL12 are switched from the off state to the on state, and the process ends. On the other hand, in step S111, it is determined that the charging from the power supply 111 to the storage battery 112 is "disabled", and the process ends. By the relay control steps shown in steps S304 to S311, on - off control that avoids the failure of the first and second power relays RL11 and RL12 becomes possible.

[0067] As described above, according to the control program of the power system 110 executed by the control device 140 and the control method of the power system 110 implemented thereby, similar to the first embodiment, by the correction steps shown in steps S301 to S303, it is possible to correct so that the detection voltage obtained from the first voltage monitor circuit 121 and the detection voltage obtained from the second voltage monitor circuit 122 do not deviate in the same - potential connection state. After executing the correction steps, since the relay control steps shown in steps S304 to S311 are executed, more reliably, on - off control that avoids the failure of the first and second power relays RL11 and RL12 becomes possible. As a result, in the power system 110 capable of controlling the electrical connection / disconnection between the power supply 111 and the storage battery 112 by the on - off control of the first and second power relays RL11 and RL12, it becomes possible to appropriately control the first and second power relays RL11 and RL12.

[0068] (Modification example) As in the power supply system 210 shown in FIG. 8, the first and second auxiliary power supply relays RL13 and RL14 may be included in the in-vehicle circuit 220.

[0069] 9 , the first and second auxiliary power supply relays RL15, RL16 may be included in the on-board circuit 320 and provided in the high potential path and low potential path, respectively, between the storage battery 112 and the second voltage monitor circuit 221. In the power supply system 310, the first and second auxiliary power supply relays RL15, RL16 are provided in the high potential path and low potential path, respectively, on the storage battery 112 side of the power supply circuit that includes the first and second power supply relays RL11, RL12, the first voltage monitor circuit 121, and the second voltage monitor circuit 122.

[0070] When the RL control unit 343 controls the first and second power supply relays RL11, RL12 to an ON state and controls the first and second auxiliary power supply relays RL15, RL16 to an OFF state, the power supply 111 and the storage battery 112 are disconnected from each other, and the high potential side and low potential side of the first voltage monitor circuit 121 are connected to the same potential as the high potential side and low potential side of the second voltage monitor circuit 122. This state is a state in which the storage battery 112 and the power supply 111 are disconnected and the high potential side and low potential side of the first voltage monitor circuit 121 are connected to the same potential as the high potential side and low potential side of the second voltage monitor circuit 122, respectively, and corresponds to an equal potential connection state.

[0071] When the RL control unit 143 controls the first and second power supply relays RL11, RL12 to the OFF state and the first and second auxiliary power supply relays RL15, RL16 to the ON state, the power supply 111 and the storage battery 112 are disconnected from each other, and the high potential side and low potential side of the second voltage monitor circuit 122 are connected to the storage battery 112. This state corresponds to a relay ON determination state.

[0072] In the above-described embodiments, a flowchart has been described in which the correction unit executes the correction process and then the RL control unit executes the relay control process, but the present invention is not limited to this. The correction process does not have to be executed every time the relay control process is executed, and may be configured to be executed at a predetermined interval or each time the relay control process is executed.

[0073] The controller and methods described herein may be implemented by a special-purpose computer configured with a processor and memory programmed to perform one or more functions embodied in a computer program. Alternatively, the controller and methods described herein may be implemented by a special-purpose computer configured with a processor configured with one or more dedicated hardware logic circuits. Alternatively, the controller and methods described herein may be implemented by one or more special-purpose computers configured with a processor and memory programmed to perform one or more functions in combination with a processor configured with one or more hardware logic circuits. Furthermore, the computer program may be stored as instructions executed by a computer on a computer-readable non-transitory storage medium. [Explanation of symbols]

[0074] 10... Power supply system, 11... Power supply, 12... Storage battery, 21... First monitor circuit, 22... Second monitor circuit, 40... Control device, 41... Correction unit, 43... Relay control unit, RL1, RL2... Power supply relays, SW1 to SW4... Switches

Claims

1. power supply relays (RL1, RL2, RL11, RL12) respectively provided in a high potential path and a low potential path between the power supply (11) and the storage battery (12); a first voltage monitor circuit (21, 121) that detects a voltage between the high potential path and the low potential path on the power supply side or the storage battery side of the power supply relay as a first voltage; a second voltage monitor circuit (22, 122) that detects a voltage between the high potential path and the low potential path as a second voltage on the opposite side of the power supply relay from the first voltage monitor circuit; a relay control unit (43, 143, 343) that switches the power supply relay to an ON state on condition that a voltage difference between the first voltage detected by the first voltage monitor circuit and the second voltage detected by the second voltage monitor circuit in a state in which the power supply relay is OFF is equal to or smaller than a predetermined ON voltage difference; A power supply system (10, 110, 310) comprising: switching circuits (SW1 to SW4, RL13 to RL16) for switching the high potential side and the low potential side of the first voltage monitor circuit to an equal potential connection state in which the high potential side and the low potential side of the second voltage monitor circuit are connected to the same potential as the high potential side and the low potential side of the second voltage monitor circuit, respectively, in a state in which the storage battery and the power supply are disconnected; a correction unit (41, 141, 341) that sets the same potential connection state using the switching circuit and executes a correction process to correct at least one of the first voltage and the second voltage based on a voltage difference between the first voltage detected by the first voltage monitor circuit and the second voltage detected by the second voltage monitor circuit.

2. The switching circuit control switches (SW1, SW2) provided between the first voltage monitor circuit and the high potential path and the low potential path on the opposite side of the power supply relay from the second voltage monitor circuit; correction switches (SW3, SW4) provided between the first voltage monitor circuit and the high potential path and the low potential path on the same side of the power supply relay as the second voltage monitor circuit, The correction unit performing the correction process based on a voltage difference between the voltage acquired from the first voltage monitor circuit and the voltage acquired from the second voltage monitor circuit in a state in which the power supply relay is turned off, the control switch is turned off, and the correction switch is turned on; The relay control unit 2. The power supply system according to claim 1, wherein, after the correction process is performed, the control switch is controlled to an on state, and with the correction switch controlled to an off state, the power supply relay is switched to an on state on the condition that a voltage difference between a first voltage detected by the first voltage monitor circuit and a second voltage detected by the second voltage monitor circuit is equal to or less than the on-voltage difference.

3. The switching circuit and auxiliary power supply relays (RL13 to RL16) provided in the high potential path and the low potential path at least either between the power supply circuit including the power supply relay, the first voltage monitor circuit, and the second voltage monitor circuit and the power supply, or between the power supply circuit and the storage battery, The correction unit executing the correction process based on a voltage difference between the voltage detected by the first voltage monitor circuit and the voltage detected by the second voltage monitor circuit while controlling the power supply relay to an ON state and controlling the secondary power supply relay to an OFF state; The relay control unit 2. The power supply system according to claim 1, wherein, with the power supply relay controlled to an off state and the secondary power supply relay controlled to an on state, the power supply relay is switched to an on state on the condition that a voltage difference between a first voltage detected by the first voltage monitor circuit and a second voltage detected by the second voltage monitor circuit is equal to or less than the on-voltage difference.

4. power supply relays (RL1, RL2, RL11, RL12) respectively provided in a high potential path and a low potential path between the power supply (11) and the storage battery (12); a first voltage monitor circuit (21, 121) that detects a voltage between the high potential path and the low potential path on the power supply side or the storage battery side of the power supply relay as a first voltage; a second voltage monitor circuit (22, 122) that detects a voltage between the high potential path and the low potential path as a second voltage on the opposite side of the power supply relay from the first voltage monitor circuit; a switching circuit (SW1 to SW4, RL13 to RL16) for switching to an equal potential connection state in which the high potential side and the low potential side of the first voltage monitor circuit are connected to the same potential as the high potential side and the low potential side of the second voltage monitor circuit, respectively, when the storage battery and the power supply are disconnected, the control program for the power supply system including: a correcting step of correcting at least one of the first voltage and the second voltage based on a voltage difference between the first voltage detected by the first voltage monitor circuit and the second voltage detected by the second voltage monitor circuit, with the switching circuit setting the same potential connection state; a relay control step of switching the power supply relay to an on state, on condition that a voltage difference between the first voltage detected by the first voltage monitor circuit and the second voltage detected by the second voltage monitor circuit in a state in which the power supply relay is turned off is equal to or smaller than a predetermined on-voltage difference.

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