Control device

Abstract

To provide a control device capable of effectively utilizing power discharged from a capacitor after ignition of a vehicle is turned off.SOLUTION: The control device for an on-vehicle power supply system comprises: a main power supply that supplies electric power to a load mounted on a vehicle; a redundant power supply that includes a capacitor for storing electric power and supplies electric power from the capacitor to the load when the main power supply fails; and a relay that switches the power supply source to the load to either the main power supply or the redundant power supply. After ignition of the vehicle is turned off, a discharge process of the capacitor is started, and a fixation prevention process of the relay using the electric power of the capacitor is executed during the discharging process of the capacitor.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a control device mounted on a vehicle. [Background technology]

[0002] Patent document 1 discloses a control device that includes a first power supply system that supplies power to an electric brake device (load) installed in a vehicle, and a second power supply system that supplies power from a capacitor to the electric brake device via a relay in the event of a failure in the first power supply system. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-014173 Summary of the Invention [Problem to be solved by the invention]

[0004] In the control device described in Patent Document 1, after the vehicle ignition is turned off, a discharge process is performed by connecting the capacitor to the ground, and the power (charge) of the capacitor is not effectively utilized. Therefore, there is room for consideration of a method for effectively utilizing the power of the capacitor after the vehicle ignition is turned off.

[0005] The present disclosure has been made in consideration of the above-mentioned problems, and aims to provide a control device that can effectively utilize the power discharged from a capacitor after the vehicle ignition is turned off. [Means for solving the problem]

[0006] In order to solve the above problems, one aspect of the disclosed technology is a control device for an on-board power supply system that includes a main power supply that supplies power to a load mounted on a vehicle, a redundant power supply that includes a storage capacitor and supplies power from the capacitor to the load in the event of a failure of the main power supply, and a relay that switches the power supply source to the load between the main power supply and the redundant power supply, and the control device starts a discharge process for the capacitor after the vehicle ignition is turned off, and performs a process to prevent the relay from sticking using power from the capacitor while the capacitor discharge process is being performed. [Effects of the Invention]

[0007] According to the control device of the present disclosure, after the vehicle ignition is turned off, the capacitor discharge process and the relay sticking prevention process using the capacitor's power are performed in parallel, so that the power discharged from the capacitor can be effectively utilized. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a functional block diagram of an in-vehicle power supply system including a control device according to an embodiment of the present disclosure and its peripheral components; [Figure 2] Flowchart showing the power supply control procedure executed by the control device after IGR-OFF [Figure 3] FIG. 10 is a diagram illustrating the difference between the power control of the present invention and the power control example of the prior art. DETAILED DESCRIPTION OF THE INVENTION

[0009] When the vehicle ignition is turned off, the control device of the present disclosure first performs a fault diagnosis on the redundant power supply and then starts a capacitor discharge process. While the control device is performing this capacitor discharge process, it also performs a process to prevent the relays that switchably connect the load and each power supply (main power supply and redundant power supply) from sticking. This allows the power (charge) discharged from the capacitor to be used effectively and shortens the time required to complete the capacitor discharge. Hereinafter, an embodiment of the present disclosure will be described in detail with reference to the drawings.

[0010] <Embodiment> [composition] 1 is a functional block diagram of an in-vehicle power supply system 100 including a control device 123 according to an embodiment of the present disclosure and its peripheral components. The functional block illustrated in FIG. 1 includes the in-vehicle power supply system 100 equipped with a main power supply 110, a redundant power supply 120, and a mechanical relay 130, a door lock motor 140, and a body ECU 150.

[0011] The main power supply 110 is configured to supply power to a load such as a door lock motor 140 mounted on the vehicle. A secondary battery configured to be rechargeable, such as a lead battery, is used as the main power supply 110. The main power supply 110 is connected to the door lock motor 140 via a mechanical relay 130.

[0012] Redundant power supply 120 is a sub-power supply configured to be redundant for main power supply 110, and is configured to supply backup power to loads such as door lock motor 140 mounted on a vehicle in the event of a failure of main power supply 110. This redundant power supply 120 is a system including capacitor 121, semiconductor relay 122, control device 123, and discharge circuit 124.

[0013] Capacitor 121 is a storage element (capacitor for storing electricity) for storing backup power, which is power to be supplied to in-vehicle devices that require a redundant power supply configuration, such as door lock motor 140, when main power supply 110 fails.

[0014] The semiconductor relay 122 is inserted between the capacitor 121 and the mechanical relay 130, and is configured to switch between an electrically conductive and cut-off state (BACT relay) based on instructions from the control device 123. For example, a metal oxide semiconductor field effect transistor (MOSFET) or the like can be used for the semiconductor relay 122.

[0015] Discharge circuit 124 is configured to discharge the power (charge) stored in capacitor 121 based on an instruction from control device 123. Discharge circuit 124 includes a resistive element or the like.

[0016] The control device 123 is configured to control switching between electrical conduction and cut-off states of the semiconductor relay 122 and switching between discharge and non-discharge states of the discharge circuit 124 based on the state of the IGR signal and a request signal from the body ECU 150. The IGR signal indicates the state of the vehicle's ignition (IG-ON or IG-OFF), and is input to the in-vehicle power supply system 100 from a predetermined in-vehicle device. The control device 123 is configured, for example, by a microcomputer. The control device 123 can also perform fault diagnosis of the redundant power supply 120. More specifically, in the fault diagnosis of the redundant power supply 120, the control device 123 can check for malfunctions of the semiconductor relay 122 and the discharge circuit 124. The control device 123 can also perform a process to prevent sticking of the mechanical relay 130. More specifically, in the process to prevent sticking of the mechanical relay 130, the control device 123 can perform conduction to prevent sticking of the contacts of the mechanical relay 130.

[0017] The mechanical relay 130 is inserted between the main power supply 110 and the redundant power supply 120 and the door lock motor 140, and is configured to control the state of power supply from the main power supply 110 and the redundant power supply 120 to the door lock motor 140. For example, a single-pole, double-throw, excitation-type mechanical relay can be used as this mechanical relay 130. The mechanical relay 130 has a coil that operates based on the control of the body ECU 150, and can be switched between a connection state (hereinafter referred to as a "first connection state") in which power can be supplied from the main power supply 110 to the door lock motor 140, and a connection state (hereinafter referred to as a "second connection state") in which power can be supplied from the redundant power supply 120 to the door lock motor 140.

[0018] The door lock motor 140 is a motor actuator for locking the vehicle doors. The door lock motor 140 is driven by power supplied via the mechanical relay 130, and this drive can lock the vehicle doors. In addition to the door lock motor 140, there is also an electric latch mechanism (E-latch) that does not require power switching by the mechanical relay 130 as a mechanism for locking the vehicle doors.

[0019] The body ECU 150 is one of the electronic control units (ECUs) that are devices mounted on the vehicle. The body ECU 150 is configured to be able to control switching of the connection state of the power supply source of the mechanical relay 130. When switching the connection state of the mechanical relay 130 to a connection state (second connection state) that allows power to be supplied from the redundant power supply 120 to the door lock motor 140, the body ECU 150 outputs a door unlock request (signal) to the control device 123 of the redundant power supply 120. At this time, the body ECU 150 can also output a request to the control device 123 of the redundant power supply 120 to clean the contacts of the mechanical relay 130. Note that the control performed by the body ECU 150 may be performed by another ECU mounted on the vehicle.

[0020] [control] Next, the control executed by the in-vehicle power supply system 100 of this embodiment will be described with further reference to Figures 2 and 3. Figure 2 is a flowchart showing the processing procedure for power supply control after IGR-OFF executed by the control device 123. Figure 3 is a diagram explaining the difference in processing between the power supply control of the present invention and an example of power supply control of the prior art.

[0021] The power supply control shown in FIG. 2 starts when in-vehicle power supply system 100 receives an IGR signal (IGR-OFF) indicating that the vehicle ignition has been turned off.

[0022] (Step S201) The control device 123 starts a fault diagnosis of the redundant power supply 120. A known method can be used for this fault diagnosis. When the control device 123 starts a fault diagnosis of the redundant power supply 120, the process proceeds to step S202.

[0023] (Step S202) The control device 123 determines whether or not the failure diagnosis of the redundant power supply 120 is complete. If the control device 123 determines that the failure diagnosis of the redundant power supply 120 is complete (Yes in step S202), the process proceeds to step S203.

[0024] (Step S203) The control device 123 switches the discharge circuit 124 to a discharging state and starts control to discharge the power (charge) of the capacitor 121. When the control device 123 starts discharging the capacitor 121, the process proceeds to step S204.

[0025] (Step S204) The control device 123 determines whether or not there is a request from the body ECU 150 to clean the contacts of the mechanical relay 130. Cleaning the contacts of the mechanical relay 130 is a process of burning off and removing a thin film of foreign matter or the like that adheres to the surface of the contacts by passing an electric current through the contacts. If the control device 123 determines that there is a request to clean the contacts of the mechanical relay 130 (Yes in step S204), the process proceeds to step S205. On the other hand, if the control device 123 determines that there is no request to clean the contacts of the mechanical relay 130 (No in step S204), the process proceeds to step S206.

[0026] (Step S205) The control device 123 controls the semiconductor relay 122 to be in a conductive state (ON) for a predetermined time. This control, together with the body ECU 150's control of switching the second connection state of the mechanical relay 130, allows current to flow through the contacts of the mechanical relay 130 for cleaning purposes. The predetermined time can be set arbitrarily (for example, 4 minutes) based on the time required for the vehicle occupants to get off the vehicle and lock the vehicle doors, while taking into consideration the time required to burn off and remove a thin film of foreign matter adhering to the surface of the contacts. When the control device 123 has set the semiconductor relay 122 to be in a conductive state (ON) for the predetermined time, the process proceeds to step S206.

[0027] (Step S206) The control device 123 determines whether or not the discharge of the capacitor 121 has been completed. The completion of the discharge can be determined when the voltage of the capacitor 121 becomes equal to or lower than a predetermined value. If the control device 123 determines that the discharge of the capacitor 121 has been completed (Yes in step S206), the process proceeds to step S207. On the other hand, if the control device 123 determines that the discharge of the capacitor 121 has not been completed (No in step S206), the process proceeds to step S204.

[0028] (Step S207) The control device 123 transitions the function of the redundant power supply 120 to a predetermined sleep state. When the control device 123 transitions the redundant power supply 120 to the sleep state, this power supply control ends.

[0029] The above-described control allows the discharged power of the capacitor 121 to be used for cleaning the contacts of the mechanical relay 130, rather than simply being discarded. This allows the power (charge) discharged from the capacitor 121 to be used effectively. Furthermore, the above-described control allows the processes of fault diagnosis, capacitor discharge, and relay contact cleaning to be efficiently executed, as illustrated in FIG. 3. This allows the present invention (FIG. 3(a)) to shorten the time it takes for the redundant power supply 120 to transition to a sleep state compared to the prior art (FIG. 3(b)).

[0030] <Actions and Effects> As described above, according to the control device 123 of one embodiment of the present disclosure, when the vehicle ignition is turned off (IGR-OFF), first a fault diagnosis of the redundant power supply 120 is performed, and then the discharge process of the capacitor 121 that constitutes the redundant power supply 120 is started, and while this discharge process is being performed, contact cleaning of the mechanical relay 130, i.e., a process to prevent sticking, is performed in parallel.

[0031] This control allows the discharge process of capacitor 121 and the contact cleaning process (anti-sticking process) of mechanical relay 130 using this discharge power to be carried out in parallel, thereby making it possible to effectively utilize the power (charge) discharged from capacitor 121 and shorten the time it takes for capacitor 121 to complete discharge.

[0032] The above describes one embodiment of the disclosed technology, but the present disclosure can be understood as an on-board power supply system that includes a control device, a control method executed by the control device having a processor and a memory, a control program for executing the control method, a computer-readable non-transitory storage medium that stores the control program, and the control device. [Industrial Applicability]

[0033] The control device of the present disclosure can be used in an in-vehicle power supply system that includes a main power supply and a redundant power supply. [Explanation of symbols]

[0034] 100 Automotive Power Supply System 110 Main power supply 120 redundant power supply 121 Capacitor 122 Solid State Relay 123 Control Device 124 Discharge circuit 130 Mechanical Relay 140 Door lock motor 150 Body ECU

Claims

1. a main power supply that supplies power to a load mounted on the vehicle; a redundant power supply including a storage capacitor for supplying power to the load from the capacitor when the main power supply fails; a relay for switching a power supply source to the load between the main power supply and the redundant power supply, a control device that starts a discharge process of the capacitor after the ignition of the vehicle is turned off, and executes a process to prevent the relay from sticking by switching the relay to a state in which power from the capacitor is supplied to the load for a predetermined time while the discharge process of the capacitor is being performed.

2. 2. The control device according to claim 1, wherein the control device executes the process for preventing the relay from sticking when a predetermined request signal is received from an apparatus mounted on the vehicle while the process for discharging the capacitor is being performed.

3. the load is a door lock motor, The control device according to claim 1 , wherein the predetermined time is set based on a time required for an occupant of the vehicle to exit the vehicle and lock the vehicle doors.

4. 4. The control device according to claim 1, wherein a fault diagnosis of the redundant power supply is performed before the capacitor is discharged.

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