Power supply device

Abstract

A power supply device (10) includes: an auxiliary power supply (10A); and a control circuit (10C) configured to control charging and discharging of the auxiliary power supply (10A). The control circuit (10C) is configured to charge the auxiliary power supply (10A) after waiting for the completion of the driving preparation of the vehicle after the completion of the initial check. The control circuit (10C) is configured to charge the auxiliary power supply (10A) in a case where both of the first condition and the second condition are satisfied after the initial check is completed, even before a driving preparation of the vehicle is completed. The first condition is a condition in which an amount of elapsed time from when the initial check is completed is equal to or greater than a time threshold. The second condition is a condition in which a voltage across the auxiliary power supply (10A) is less than a voltage threshold.

Description

Technical Field

[0001] The present disclosure relates to a power supply device. Background Art

[0002] A power supply device is known that provides electrical feeding to an electrical feeding target by means of an auxiliary power supply when a main power supply fails. For example, a power supply device in Japanese Unexamined Patent Application Publication No. 2023-18841 is provided in an electrical feeding path between a main power supply of a vehicle and a steering control device. The power supply device has an auxiliary power supply and a charging circuit. The auxiliary power supply is, for example, a lithium ion capacitor. The charging circuit is a circuit for charging the auxiliary power supply. Summary of the invention

[0003] The auxiliary power supply has a self-discharge characteristic. Therefore, even in a state where the auxiliary power supply is not used, the available amount of the auxiliary power supply gradually decreases over time. Therefore, when the auxiliary power supply is not charged for a long period of time due to some reasons, there is a concern that the auxiliary power supply reaches an over-discharge state. When the over-discharge state continues for a long period of time, there is a concern that the auxiliary power supply is degraded. The present disclosure provides a power supply device that reduces the degradation of the auxiliary power supply due to over-discharge.

[0004] A power supply device according to one aspect of the present disclosure includes: an auxiliary power supply; and a control circuit. The auxiliary power supply is configured as a backup for a vehicle-mounted main power supply configured to supply power to an electrical feeding target. The control circuit is configured to control the charging of the auxiliary power supply by electricity from the main power supply and the discharge of the auxiliary power supply. The control circuit is configured to perform an initial check when the power switch of the vehicle is turned on, which is an initial stage inspection at startup. The control circuit is configured to charge the auxiliary power supply after waiting for the vehicle's driving preparation to be completed after the initial check is completed. The control circuit is configured to charge the auxiliary power supply after the initial check is completed, even before the vehicle's driving preparation is completed, when both of the first condition and the second condition are met. The first condition is a condition that the amount of time elapsed from the time the initial check is completed is equal to or greater than a time threshold. The second condition is a condition that the voltage across the auxiliary power supply is less than a voltage threshold.

[0005] It is envisaged that the vehicle's travel preparation is not completed for a long period of time due to some reasons. In this case, the discharge or electricity consumption of the auxiliary power supply proceeds, and there is a concern that the auxiliary power supply reaches an over-discharge state in the time period from when the power switch is turned on to when the vehicle's travel preparation is completed. In this regard, according to the above configuration, the auxiliary power supply is charged even before the vehicle's travel preparation is completed with the power switch turned on, when the amount of time elapsed from the completion of the initial check is equal to or greater than the time threshold and the voltage across the auxiliary power supply is less than the voltage threshold. Therefore, it is possible to reduce the situation in which the discharge or electricity consumption of the auxiliary power supply proceeds and the auxiliary power supply reaches an over-discharge state in the time period from when the power switch is turned on to when the vehicle's travel preparation is completed. Therefore, it is possible to reduce the degradation of the auxiliary power supply due to over-discharge.

[0006] In a power supply device according to one aspect of the present disclosure, the auxiliary power supply may have an output voltage lower than an output voltage of the main power supply and is configured to be charged by a voltage across the main power supply stepped down by an on-board DC-DC converter. The vehicle's travel preparation may include a start-up process of the DC-DC converter.

[0007] According to this configuration, the auxiliary power supply is charged by the voltage across the main power supply stepped down by the DC-DC converter. Therefore, it is basically preferred to charge the auxiliary power supply after waiting for the activation of the DC-DC converter when the power switch is turned on.

[0008] In the power supply device according to an aspect of the present disclosure, the voltage threshold may be set to a minimum voltage value required for backup of the main power supply.

[0009] The auxiliary power supply is charged by the electricity of the main power supply. Therefore, when the auxiliary power supply is charged, the electricity of the main power supply is consumed. In this regard, according to the above configuration, compared with the case where the voltage threshold is set to a value greater than the minimum voltage value required for the backup of the main power supply, the time period from when the initial check by the control circuit is completed to when the second condition that the voltage across the auxiliary power supply is less than the voltage threshold is satisfied can be made longer. Therefore, the electricity consumption of the main power supply before the start-up of the DC-DC converter can be reduced.

[0010] In a power supply device according to one aspect of the present disclosure, the electric feeding target may be a control device of a vehicle, the control device being configured to send a charging permission signal to a control circuit when the vehicle is ready to travel. The control circuit may be configured to recognize that the vehicle is ready to travel when receiving the charging permission signal.

[0011] According to this configuration, the control circuit can easily recognize that the vehicle's driving preparation is complete by receiving a charging permission signal from the vehicle's control device. In a power supply device according to one aspect of the present disclosure, the control device can be a steering control device configured to control a motor that serves as a driving source for the vehicle's steering device.

[0012] This power supply is suitable for steering control equipment that requires higher reliability.

[0013] According to the power supply device of the present disclosure, degradation of the auxiliary power supply due to overdischarge can be reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Features, advantages, and technical and industrial significance of exemplary embodiments of the present invention will be described below with reference to the accompanying drawings, in which like reference numerals denote like elements, and in which:

[0015] Figure 1 is a block diagram of a vehicle power supply system including a power supply device and a steering control apparatus according to one embodiment;

[0016] Figure 2 is a flowchart showing one example of a process performed by a control circuit of a power supply device according to one embodiment; and

[0017] Figure 3 is a graph showing a voltage usage range of an auxiliary power supply according to one embodiment. DETAILED DESCRIPTION

[0018] One embodiment of the power supply device is described below.

[0019] like Figure 1 As shown, the power supply device 10 is arranged in the electric feeding path between the main power supply 20 and the steering control device 30 as the electric feeding target. The main power supply 20 is connected to the power supply device 10 via a DC-DC converter 21. The power supply device 10 is located between the DC-DC converter 21 and the steering control device 30, and serves as a backup for the main power supply 20. The expression "DC" is an abbreviation of "direct current" and means "direct current". The main power supply 20 is also connected to an auxiliary machine battery 22 via a DC-DC converter 21.

[0020] For example, the main power supply 20 is a lithium-ion battery or a nickel-metal hydride battery. The main power supply 20 is an on-vehicle power supply backed up by the power supply device 10. The DC-DC converter 21 steps down the output voltage at both ends of the main power supply 20. The power from the DC-DC converter 21 is supplied to the steering control device 30 via the power supply device 10.

[0021] For example, the auxiliary machine battery 22 is a lead storage battery. The output voltage across the auxiliary machine battery 22 is lower than the output voltage across the main power supply 20. The DC-DC converter 21 steps down the output voltage across the main power supply 20, and charges the auxiliary machine battery 22 with the stepped-down voltage. The power of the auxiliary machine battery 22 is supplied to the vehicle-mounted auxiliary machines.

[0022] The steering control device 30 is one of the control devices of the vehicle. The steering control device 30 controls the motor as the driving source of the steering device of the vehicle. For example, the steering device is a wire-controlled steering device, and the power transmission between the steering wheel and the steering wheel is separated. The motor includes a reaction force motor 41 and a steering motor 42.

[0023] The reaction force motor 41 is a source of the steering reaction force. The steering reaction force is a force in the direction opposite to the operation direction of the steering wheel. For example, the reaction force motor 41 is a three-phase brushless motor and has two winding group systems. The winding group includes a first system winding group N11 and a second system winding group N12. The torque of the reaction force motor 41 is applied to the steering shaft via a speed reducer.

[0024] The steering motor 42 is a source of steering force. The steering force is a force used to steer the steering wheel of the vehicle. For example, the steering motor 42 is a three-phase brushless motor and has two winding group systems. The winding group includes a first system winding group N21 and a second system winding group N22. The torque of the steering motor 42 is applied to the steering shaft via a speed reducer. The steering shaft steers the steering wheel.

[0025] The steering control apparatus 30 has a reaction force control device 31 and a steering control device 32. The reaction force control device 31 and the steering control device 32 exchange information with each other via a communication line (not shown).

[0026] The reaction force control device 31 controls the electric feed relative to the reaction force motor 41. The reaction force control device 31 has a first reaction force control unit 31A and a second reaction force control unit 31B. The first reaction force control unit 31A controls the electric feed relative to the first system winding group N11 of the reaction force motor 41. The second reaction force control unit 31B controls the electric feed relative to the second system winding group N12 of the reaction force motor 41.

[0027] The steering control device 32 controls the electric feed relative to the steering motor 42. The steering control device 32 has a first steering control unit 32A and a second steering control unit 32B. The first steering control unit 32A controls the electric feed relative to the first system winding group N21 of the steering motor 42. The second steering control unit 32B controls the electric feed relative to the second system winding group N22 of the steering motor 42.

[0028] Electrical feed path

[0029] Next, an electrical feed path between the main power source 20 and the steering control device 30 is described.

[0030] like Figure 1 As shown, the power supply device 10 is connected to the DC-DC converter 21 via the first power supply line L1. The power supply device 10 is connected to the DC-DC converter 21 via the second power supply line L2. The power switch 23 is provided in the second power supply line L2. For example, the power switch 23 includes an ignition switch, and is operated when the driving source of the vehicle is started or stopped. For example, the driving source is an engine or a driving motor. By the operation of the power switch 23, the conduction of the second power supply line L2 is switched between on and off.

[0031] The first reaction force control unit 31A is connected to the DC-DC converter 21 via the power supply device 10. The first reaction force control unit 31A is connected to the power supply device 10 via the third power line L3. The third power line L3 is branched from the first power line L1 inside the power supply device 10. The first reaction force control unit 31A is connected to the power supply device 10 via the fourth power line L4. The fourth power line L4 is branched from the second power line L2 inside the power supply device 10.

[0032] The electricity from the DC-DC converter 21 is supplied to the power circuit of the first reaction force control unit 31A via the first power line L1, the power supply device 10, and the third power line L3. For example, the power circuit is a circuit that processes larger electricity, and includes an inverter that converts the direct current from the DC-DC converter 21 into alternating current. The electricity from the DC-DC converter 21 is supplied to the control circuit of the first reaction force control unit 31A via the second power line L2, the power supply device 10, and the fourth power line L4. For example, the control circuit is a circuit for controlling the reaction force motor 41, and includes a central processing unit (CPU) and a memory. The memory includes a random access memory (RAM) and a read-only memory (ROM).

[0033] The first steering control unit 32A is connected to the DC-DC converter 21 via the power supply device 10. The first steering control unit 32A is connected to the power supply device 10 via the fifth power line L5. The fifth power line L5 is branched from the first power line L1 inside the power supply device 10. The first steering control unit 32A is connected to the power supply device 10 via the sixth power line L6. The sixth power line L6 is branched from the second power line L2 inside the power supply device 10.

[0034] The power from the DC-DC converter 21 is supplied to the power circuit of the first steering control unit 32A via the first power line L1, the power supply device 10, and the fifth power line L5. The power from the DC-DC converter 21 is supplied to the control circuit of the first steering control unit 32A via the second power line L2, the power supply device 10, and the sixth power line L6.

[0035] The second reaction force control unit 31B is connected to the DC-DC converter 21 without passing through the power supply device 10. The second reaction force control unit 31B is connected to the DC-DC converter 21 via the seventh power line L7. The second reaction force control unit 31B is connected to the DC-DC converter 21 via the eighth power line L8. When described in detail, the second reaction force control unit 31B is connected to the first connection point P1 provided in the second power line L2 via the eighth power line L8. The first connection point P1 is provided between the power switch 23 and the power supply device 10 in the second power line L2.

[0036] The power from the DC-DC converter 21 is supplied to the power circuit of the second reaction force control unit 31B via the seventh power line L7. The power from the DC-DC converter 21 is supplied to the control circuit of the second reaction force control unit 31B via a part of the second power line L2 and the eighth power line L8.

[0037] The second steering control unit 32B is connected to the DC-DC converter 21 without passing through the power supply device 10. The second steering control unit 32B is connected to the DC-DC converter 21 via the ninth power supply line L9. The second steering control unit 32B is connected to the DC-DC converter 21 via the tenth power supply line L10. When described in detail, the second steering control unit 32B is connected to the second connection point P2 provided in the eighth power supply line L8 via the ninth power supply line L9.

[0038] The power from the DC-DC converter 21 is supplied to the power circuit of the second steering control unit 32B via the ninth power line L9. The power from the DC-DC converter 21 is supplied to the control circuit of the second steering control unit 32B via a portion of the second power line L2, a portion of the eighth power line L8, and the tenth power line L10.

[0039] The main power source 20, the DC-DC converter 21, the auxiliary machine battery 22, the power source device 10, and the steering control apparatus 30 configure a vehicle power source system.

[0040] Power supply unit

[0041] Next, the configuration of the power supply device 10 is described.

[0042] The power supply device 10 includes an auxiliary power supply 10A, a switching circuit 10B, and a control circuit 10C.

[0043] The auxiliary power source 10A is an electric storage device capable of charging and discharging electric charge, and is, for example, a lithium ion capacitor or a lithium ion battery. For example, the voltage across the auxiliary power source 10A is higher than the lower limit value of the voltage required for backup of the auxiliary machine battery 22 - in other words, the lower limit value of the voltage required for proper operation of the steering control device 30 - and is lower than the voltage across the auxiliary machine battery 22.

[0044] The switch circuit 10B switches the connection state of the auxiliary power supply 10A relative to the first power supply line L1 so that charging of the auxiliary power supply 10A is performed based on the command from the control circuit 10C. In other words, the switch circuit 10B opens and closes the charging path between the auxiliary power supply 10A and the first power supply line L1. The switch circuit 10B switches the power of the first reaction force control unit 31A and the first steering control unit 32A between the main power supply 20 and the auxiliary power supply 10A based on the command from the control circuit 10C. In other words, the switch circuit 10B opens and closes the discharge path between the auxiliary power supply 10A and the third power supply line L3 and between the auxiliary power supply 10A and the fourth power supply line L4. The switch circuit 10B opens and closes the discharge path between the auxiliary power supply 10A and the fifth power supply line L5 and between the auxiliary power supply 10A and the sixth power supply line L6.

[0045] The power of the main power supply 20 or the auxiliary power supply 10A switched by the switch circuit 10B is supplied to the first reaction force control unit 31A via the third power line L3 and the fourth power line L4. The power of the main power supply 20 or the auxiliary power supply 10A switched by the switch circuit 10B is supplied to the first steering control unit 32A via the fifth power line L5 and the sixth power line L6.

[0046] The control circuit 10C has a processing circuit including any of the following three configurations A1, A2, A3.

[0047] A1. One or more processors operating according to a computer program as software. The processor includes a CPU and a memory.

[0048] A2. One or more dedicated hardware circuits, such as an application specific integrated circuit (ASIC) that performs at least some of the various processes.

[0049] A3. Hardware circuit obtained by combining the two configurations A1, A2.

[0050] The memory is a medium that can be read by a computer and stores a program in which processing or instructions about the computer are written. In this embodiment, the computer is a CPU. The memory includes a RAM and a ROM. The CPU performs various controls by executing the program stored in the memory in a fixed operation cycle.

[0051] The control circuit 10C controls the switching of the switch circuit 10B. The control circuit 10C monitors the voltage across the main power supply 20. When the value of the voltage across the main power supply 20 is less than the voltage threshold value, the control circuit 10C determines that the voltage across the main power supply 20 has decreased. The voltage threshold value is a reference for determining when the voltage across the main power supply 20 has decreased. The voltage threshold value is set with reference to the lower limit value of the voltage required to properly operate the reaction force motor 41 and the steering motor 42 and the first reaction force control unit 31A and the first steering control unit 32A.

[0052] When a decrease in the voltage across the main power supply 20 is not detected, the control circuit 10C generates a first command with respect to the switch circuit 10B. The first command is a command for switching the power supplies of the first reaction force control unit 31A and the first steering control unit 32A to the main power supply 20. The first command is also a command for switching the connection state of the auxiliary power supply 10A with respect to the first power supply line L1 so that charging of the auxiliary power supply 10A is performed.

[0053] When a decrease in the voltage across the main power supply 20 is detected, the control circuit 10C generates a second command with respect to the switch circuit 10B. The second command is a command for switching the power supply of the first reaction force control unit 31A and the first steering control unit 32A from the main power supply 20 to the auxiliary power supply 10A. The second command is also a command for switching the connection state of the auxiliary power supply 10A with respect to the first power supply line L1 so that charging of the auxiliary power supply 10A is not performed.

[0054] The control circuit 10C detects the charge amount of the auxiliary power supply 10A. The control circuit 10C detects the voltage across the auxiliary power supply 10A by a voltage sensor provided in the auxiliary power supply 10A, and detects the charge amount of the auxiliary power supply 10A based on the detected voltage. The voltage is the voltage across the terminals of the auxiliary power supply 10A. When the value of the voltage across the auxiliary power supply 10A is less than the voltage threshold, the control circuit 10C determines that the charge amount of the auxiliary power supply 10A is insufficient. When the value of the voltage across the auxiliary power supply 10A is equal to or greater than the voltage threshold, the control circuit 10C determines that the charge amount of the auxiliary power supply 10A is sufficient. The voltage threshold is a reference when determining whether the charge amount of the auxiliary power supply 10A is sufficient. The voltage threshold is set with reference to the lower limit value of the voltage required to properly operate the reaction force motor 41 and the steering motor 42 and the first reaction force control unit 31A and the first steering control unit 32A.

[0055] Processing of the control circuit 10C

[0056] Next, an example of the processing performed by the control circuit 10C is described. The power switch 23 is turned off as an initial state. The charging path between the auxiliary power supply 10A and the first power line L1 is opened. The discharge path between the auxiliary power supply 10A and the third power line L3 and between the auxiliary power supply 10A and the fourth power line L4 is opened. The discharge path between the auxiliary power supply 10A and the fifth power line L5 and between the auxiliary power supply 10A and the sixth power line L6 is also opened.

[0057] like Figure 2 As shown in the flowchart of , when the power switch 23 is turned on, the control circuit 10C performs an initial check (step S101). The initial check is an initial stage inspection at the start-up of the power supply device 10, and is a series of processes required for the power supply device 10 to operate. For example, the initial check includes processes such as hardware inspection and initialization of the central processing unit (CPU).

[0058] After the execution of the initial check is completed normally, the control circuit 10C transitions to the charging permission waiting state (step S102). The charging permission waiting state is a state in which charging of the auxiliary power source 10A is not permitted, and is a state of waiting for the activation of the DC-DC converter 21, in other words, a state of waiting for the completion of the travel preparation of the vehicle. This provides a reduction in the load before the activation of the DC-DC converter 21, in other words, a reduction in the power consumption of the auxiliary machine battery 22. The power from the DC-DC converter 21 is not charged to the auxiliary machine battery 22 until the DC-DC converter 21 is activated.

[0059] The vehicle has an advanced control device 50. The advanced control device 50 performs integrated control of control devices of various vehicle-mounted systems including the steering control apparatus 30. With the power switch 23 turned on, after the execution of the initial check is completed, the advanced control device 50 performs travel preparation of the vehicle. For example, the travel preparation includes the initial check by the advanced control device 50, the start-up process of the power train of the vehicle, and the start-up process of the DC-DC converter 21. When the travel preparation of the vehicle is completed and the vehicle is in a drivable state, the advanced control device 50 sends an assist start permission signal S1 to the first reaction force control unit 31A.

[0060] When the power switch 23 is turned on and after the execution of the initial check is completed, the first reaction force control unit 31A changes to the auxiliary start waiting state. The auxiliary start waiting state is a state in which the vehicle's travel preparation is waited for to be completed and the vehicle is in a travelable state. When the auxiliary start permission signal S1 is received in the auxiliary start waiting state, the first reaction force control unit 31A changes to the auxiliary start state. The auxiliary start state is a state in which the control of the steering reaction force by the reaction force motor 41 can be performed. When changing to the auxiliary start state, the first reaction force control unit 31A sends a charge permission signal S2 to the control circuit 10C.

[0061] The transition of the state of the first reaction force control unit 31A to the assist start state is sent to the second reaction force control unit 31B, the first steering control unit 32A, and the second steering control unit 32B. Therefore, at the moment when the state of the first reaction force control unit 31A is transitioned to the assist start state, the states of the second reaction force control unit 31B, the first steering control unit 32A, and the second steering control unit 32B are also transitioned to the assist start state.

[0062] When receiving the charging permission signal S2 in the standby state where the DC-DC converter 21 is activated, the control circuit 10C recognizes that the DC-DC converter 21 is activated. The charging permission signal S2 is an electrical signal indicating that the travel preparation of the vehicle is completed and the DC-DC converter 21 is activated. When the control circuit 10C recognizes that the DC-DC converter 21 is activated, the control circuit 10C transitions to a chargeable state (step S103).

[0063] The chargeable state is a state in which charging of the auxiliary power source 10A is permitted, and a state in which charging of the auxiliary power source 10A can be initiated. When the control circuit 10C is shifted to the chargeable state, the control circuit 10C checks the charge state of the auxiliary power source 10A, and determines whether the charge amount of the auxiliary power source 10A is sufficient as a backup for electrical feed to the first reaction force control unit 31A and the first steering control unit 32A.

[0064] When it is determined that the charge amount of the auxiliary power supply 10A is insufficient based on the voltage across the auxiliary power supply 10A, the control circuit 10C starts charging the auxiliary power supply 10A and waits for the charge amount of the auxiliary power supply 10A to reach a sufficient amount. When it is determined that the charge amount of the auxiliary power supply 10A is sufficient, the control circuit 10C recognizes that a standby state is obtained in which electrical feeding to the first reaction force control unit 31A and the first steering control unit 32A can be performed.

[0065] In the case where it is determined that the charge amount of the auxiliary power supply 10A is sufficient, the control circuit 10C stops charging the auxiliary power supply 10A, transitions to the standby standby state (step S104), and ends the processing. The standby standby state is a state in which the power supply device 10 can serve as a standby for power feeding to the first reaction force control unit 31A and the first steering control unit 32A, and is a state in which the power supply device 10 stands by as a standby for power feeding to the first reaction force control unit 31A and the first steering control unit 32A. When the power supply device 10 is maintained in the standby standby state, the voltage across the main power supply 20 has not yet decreased, and electricity is supplied from the main power supply 20 to the steering control device 30.

[0066] Over discharge reduction treatment

[0067] The power supply device 10 configured as described above has the following problems. For example, until the DC-DC converter 21 is activated, in other words, until the travel preparation of the vehicle by the advanced control device 50 is completed, charging of the auxiliary power supply 10A is not permitted. Therefore, when the DC-DC converter 21 is not activated for a long period of time due to some reason, there is a concern that the discharge or electricity consumption of the auxiliary power supply 10A proceeds and the auxiliary power supply 10A reaches an over-discharge state.

[0068] Therefore, the control circuit 10C performs the following processing to reduce overdischarge of the auxiliary power supply 10A. In other words, when the control circuit 10C transitions to the charging permission waiting state (step S102), even when the vehicle's travel preparation is not completed when both of the first condition B1 and the second condition B2 are satisfied, the control circuit 10C transitions to the chargeable state (step S103). The control circuit 10C can recognize that the vehicle's travel preparation is not completed by not receiving the charging permission signal S2.

[0069] B1.ΔT≥ΔT th

[0070] B2.V <V th

[0071] Note that "ΔT" is the amount of time that has passed since the transition to the charge permission waiting state. The amount of time that has passed ΔT is also the amount of time that has passed since the initial check was completed. Here, "ΔT th" is the time threshold. Here, "V" is the voltage across the auxiliary power supply 10A. Here, "V th ” is the voltage threshold.

[0072] like Figure 3 As shown, the voltage threshold V th is set to the minimum voltage value required for backup of the main power supply 20. Voltage threshold V th is set to a value greater than the first voltage V1 that causes the auxiliary power supply 10A to over-discharge and less than the second voltage V2 that causes the auxiliary power supply 10A to over-charge. A voltage range less than the first voltage V1 is an over-discharge range, and a voltage range exceeding the second voltage V2 is an over-charge range. These voltage ranges are voltage ranges in which degradation of the auxiliary power supply 10A is of concern. The use range of the voltage across the auxiliary power supply 10A is equal to or greater than the first voltage V1 and equal to or less than the second voltage V2.

[0073] is equal to or greater than the first voltage V1 and less than the voltage threshold V th The voltage range of is the limit before the auxiliary power supply 10A reaches the over-discharge state. This is based on preventing the amount of time that has passed from the control circuit 10C to the charge permission waiting state from reaching the time threshold ΔT. th The auxiliary power supply 10A reaches the over-discharge state during the time period. Equal to or greater than the voltage threshold V th The voltage range equal to or less than the second voltage V2 is a voltage range in which the self-energy is used. This is based on the viewpoint of alleviating the load on the main power source 20.

[0074] Effects of implementation methods

[0075] This embodiment exhibits the following effects.

[0076] (1) It is assumed that the vehicle's travel preparation is not completed for a long period of time due to some reason. In this case, the discharge or power consumption of the auxiliary power supply 10A proceeds, and there is a concern that the auxiliary power supply 10A reaches an over-discharged state in the period from when the power switch 23 is turned on to when the vehicle's travel preparation is completed. In this regard, according to the present embodiment, after the initial check is completed, even before the vehicle's travel preparation is completed, when the amount of time ΔT elapsed from the completion of the initial check is satisfied to be equal to or greater than the time threshold ΔT th The first condition and the voltage V across the auxiliary power supply 10A is less than the voltage threshold V th In the case of both of the second conditions, the control circuit 10C charges the auxiliary power supply 10A. Therefore, it is possible to reduce the situation in which the auxiliary power supply 10A is discharged or consumed during the period from when the power switch 23 is turned on to when the vehicle is ready to travel and the auxiliary power supply 10A reaches an over-discharge state. Therefore, it is possible to reduce the deterioration of the auxiliary power supply 10A due to over-discharge.

[0077] (2) The auxiliary power supply 10A has an output voltage lower than the output voltage across the main power supply 20 of the vehicle, and is charged by the voltage across the main power supply 20 stepped down by the on-vehicle DC-DC converter 21. The travel preparation of the vehicle includes the start-up process of the DC-DC converter 21. According to this configuration, the auxiliary power supply 10A is charged by the voltage across the main power supply 20 stepped down by the DC-DC converter 21. Therefore, it is basically preferable that the auxiliary power supply 10A is charged after waiting for the start-up of the DC-DC converter 21 with the power switch 23 turned on.

[0078] (3) The auxiliary power supply 10A is charged by the power of the main power supply 20. Therefore, when the auxiliary power supply 10A is charged, the power of the main power supply 20 is consumed. In this regard, according to the present embodiment, the voltage threshold V th is set to the minimum voltage value required for the backup of the main power supply 20. Therefore, for example, with the voltage threshold V th Compared with the case where the voltage across the auxiliary power supply 10A is set to a value greater than the minimum voltage value required for the backup of the main power supply 20, the voltage across the auxiliary power supply 10A can be reduced from the time when the initial check by the control circuit 10C is completed to the time when the voltage across the auxiliary power supply 10A is less than the voltage threshold V th Therefore, the power consumption of the main power supply 20 can be reduced, in other words, the load of the main power supply 20 can be reduced before the start-up of the DC-DC converter 21.

[0079] (4) The steering control device 30, which is one of the control devices of the vehicle, sends a charge permission signal S2 to the control circuit 10C when the vehicle is ready to travel. The control circuit 10C recognizes that the vehicle is ready to travel when receiving the charge permission signal S2. According to this configuration, the control circuit 10C can easily recognize that the vehicle is ready to travel by receiving the charge permission signal S2 from the steering control device 30.

[0080] (5) The steering control device 30 controls a motor that is a driving source of a steering device of a vehicle. A higher reliability is required for the steering control device 30. The power supply device 10 of the present embodiment is suitable for the steering control device 30.

[0081] Other Implementations

[0082] This embodiment can be implemented by the following changes.

[0083] The control circuit 10C can change to a chargeable state of the auxiliary power supply 10A after the initial check is completed, as long as the DC-DC converter 21 is activated, even in a case where the travel preparation of the vehicle is not fully completed. In this case, the control circuit 10C can obtain a signal indicating the activation state of the DC-DC converter 21 from the high-level control device 50 or from the DC-DC converter 21.

[0084] A motor having one winding group system may be adopted as the reaction force motor 41 and the steering motor 42. In this case, a configuration having only one of the first reaction force control unit 31A and the second reaction force control unit 31B may be adopted as the reaction force control device 31. A configuration having only one of the first steering control unit 32A and the second steering control unit 32B may be adopted as the steering control device 32.

[0085] The control target of the steering control device 30 may be an auxiliary motor as a driving source of the electric power steering device. The auxiliary motor is a source of generating auxiliary force. The auxiliary force is a force in the same direction as the operation direction of the steering wheel. A motor having one winding group system or a motor having two winding group systems may be used as the auxiliary motor.

[0086] The power feeding target of the power supply device 10 is not limited to the steering control apparatus 30. The power feeding target may be a control device that controls the driving of a travel motor of a battery electric vehicle (electric vehicle) or a hybrid electric vehicle (hybrid electric vehicle). The power feeding target may be a control device that controls the braking of the vehicle.

Claims

1. A power supply device (10), characterized in that include: an auxiliary power supply (10A) configured to serve as a backup for an on-vehicle main power supply (20) configured to supply power to an electrical feeding target; as well as A control circuit (10C) configured to: Controlling charging of the auxiliary power source (10A) by electricity from the main power source (20) and discharging of the auxiliary power source (10A); Performing an initial inspection when a power switch of the vehicle is turned on, the initial inspection being an initial stage inspection at startup; After the initial inspection is completed, charging the auxiliary power supply (10A) after waiting for the vehicle to be ready for travel; and After the initial check is completed, even before the vehicle is ready to travel, the auxiliary power source (10A) is charged when both the first condition and the second condition are satisfied, wherein: The first condition is a condition that the amount of time that has elapsed since the initial inspection was completed is equal to or greater than a time threshold; and The second condition is a condition that the voltage across the auxiliary power supply (10A) is less than a voltage threshold.

2. The power supply device (10) according to claim 1, characterized in that: The auxiliary power supply (10A) has an output voltage lower than an output voltage of the main power supply (20), and is configured to be charged by the voltage across the main power supply (20) stepped down by an on-board DC-DC converter (21); and The travel preparation of the vehicle includes a start-up process of the DC-DC converter (21).

3. The power supply device (10) according to claim 1 or 2, characterized in that: The voltage threshold is set to a minimum voltage value required for backup of the main power source (20).

4. The power supply device (10) according to claim 1 or 2, characterized in that: The electric feeding target is a control device of the vehicle, the control device being configured to send a charging permission signal to the control circuit (10C) when the travel preparation of the vehicle is completed; and The control circuit (10C) is configured to recognize that the travel preparation of the vehicle is completed when receiving the charging permission signal.

5. The power supply device (10) according to claim 4, characterized in that: The control device is a steering control apparatus configured to control a motor as a driving source of a steering device of the vehicle.

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