Onboard systems and vehicles

Abstract

The present disclosure relates to an in-vehicle system and vehicle. The in-vehicle system includes a main battery, a sub-battery, a braking system connected to the main battery and to the sub-battery via a semiconductor relay, a diagnostic unit for diagnosing the braking system, and a control unit for controlling the sub-battery. The diagnostic unit is configured to notify the control unit of the start of a brake system diagnosis. The control unit is configured to control the discharge of the sub-battery based on the notification of the start of diagnosis from the diagnostic unit, and is configured to make the voltage at the first terminal of the semiconductor relay connected to the sub-battery higher than the voltage at the second terminal of the semiconductor relay connected to the braking system.

Description

Technical Field

[0001] The present disclosure relates to an in-vehicle system mounted on a vehicle and the vehicle. Background Art

[0002] Japanese Patent No. 5266892 discloses a power supply system comprising a main battery, a sub-battery, and a load supplied with power from at least one of the main battery and the sub-battery. To ensure a stable power supply from the sub-battery to the load, this power supply system inserts two semiconductor relays in series between the sub-battery and the load, with the rectification directions of the parasitic diodes being opposite to each other.

[0003] To reduce the cost of the power supply system, a single semiconductor relay inserted between the sub-battery and the load is considered. However, even when the semiconductor relay is controlled to be in the off state, a path for current to flow is created due to the parasitic diode in this configuration.

[0004] Therefore, for example, when a load is connected to a sub-battery, such as in a brake system that performs self-diagnosis for abnormalities with a semiconductor relay disconnected, current escapes through a parasitic diode during the self-diagnosis of the brake system, and there is a risk that accurate diagnostic results cannot be obtained. Summary of the Invention

[0005] The present disclosure provides an in-vehicle system and a vehicle capable of obtaining accurate self-diagnosis results of a brake system in a structure in which a semiconductor relay is inserted between a sub-battery and the brake system.

[0006] The first form of the present disclosure is an on-board system mounted on a vehicle. The on-board system includes a main battery, a sub-battery, a braking system connected to the main battery and to the sub-battery via a semiconductor relay, a diagnostic unit configured to diagnose the presence or absence of abnormalities in the braking system, and a control unit configured to control the charging and discharging of the sub-battery. The main battery is configured to supply power to the braking system, and the sub-battery is configured to supply power to the braking system. The diagnostic unit is configured to notify the control unit of the start of diagnosis when the diagnosis of the braking system is started. The control unit is configured to implement discharge control of the sub-battery based on the start of diagnosis notified by the diagnostic unit. The control unit is configured to make the voltage of the first terminal of the semiconductor relay connected to the sub-battery higher than the voltage of the second terminal of the semiconductor relay connected to the braking system based on the start of diagnosis.

[0007] In the first aspect, the diagnosis unit may be configured to notify the control unit of the completion of diagnosis when the diagnosis of the brake system is completed, and the control unit may be configured to terminate the discharge control of the sub-battery based on the completion of diagnosis notified by the diagnosis unit.

[0008] In the first aspect, the diagnosis unit may be configured to notify the control unit of the completion of the diagnosis after the ignition of the vehicle is turned on.

[0009] In the first aspect, the semiconductor relay may include a parasitic diode that rectifies current from the second terminal toward the first terminal.

[0010] The second aspect of the present disclosure is a vehicle equipped with an on-board system. The vehicle includes the on-board system. The on-board system includes a main battery, a sub-battery, a braking system connected to the main battery and to the sub-battery via a semiconductor relay, a diagnostic unit for diagnosing the presence or absence of abnormalities in the braking system, and a control unit for controlling the charge and discharge of the sub-battery. The main battery is configured to supply power to the braking system, and the sub-battery is configured to supply power to the braking system. The diagnostic unit is configured to notify the control unit of the start of diagnosis when the diagnosis of the braking system is started. The control unit is configured to implement discharge control of the sub-battery based on the start of diagnosis notified by the diagnostic unit. The control unit is configured to make the voltage of the first terminal of the semiconductor relay connected to the sub-battery higher than the voltage of the second terminal of the semiconductor relay connected to the braking system based on the start of diagnosis.

[0011] The third aspect of the present disclosure is an onboard system mounted on a vehicle. The onboard system includes a main battery, a sub-battery, a braking system connected to the main battery and to the sub-battery via a semiconductor relay, a first processor for diagnosing the presence of abnormalities in the braking system, a second processor for controlling the charging and discharging of the sub-battery, and a converter located between the sub-battery and the semiconductor relay. The main battery is configured to supply power to the braking system. The sub-battery is configured to supply power to the braking system. The second processor is configured to issue a command to the converter based on a diagnostic start signal for the braking system from the first processor. Upon receiving the diagnostic start signal from the first processor, the second processor uses the converter to discharge power from the sub-battery to the semiconductor relay. The second processor is configured to increase the voltage at the first terminal of the semiconductor relay connected to the sub-battery to a higher voltage than the voltage at the second terminal of the semiconductor relay connected to the braking system based on the diagnostic start signal.

[0012] According to the first, second, and third aspects of the present disclosure, in a configuration in which one semiconductor relay is inserted between the sub-battery and the brake system, accurate self-diagnosis results of the brake system can be obtained.

[0013] Features, advantages, and technical and industrial significance of exemplary embodiments of the present invention are described below with reference to the accompanying drawings, wherein like reference numerals denote like elements. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is a schematic structural diagram of an in-vehicle system according to one embodiment of the present disclosure.

[0015] Figure 2 is a process flow chart of the control performed by the in-vehicle system. DETAILED DESCRIPTION

[0016] The in-vehicle system disclosed herein employs a semiconductor relay inserted between a secondary battery and a braking system. In this configuration, when the braking system performs self-diagnosis, the redundant power supply system controlling the secondary battery is notified of the start of diagnostic processing. Upon receiving this notification, the redundant power supply system discharges the secondary battery, causing the voltage on the secondary battery side of the semiconductor relay to be higher than the voltage on the braking system side. This control ensures that the voltage across the semiconductor relay on the secondary battery side is higher than that on the braking system side, preventing current from flowing from the braking system to the redundant power supply system via the parasitic diode of the semiconductor relay.

[0017] Hereinafter, one embodiment of the present disclosure will be described in detail with reference to the drawings.

[0018] <Implementation Method>

[0019] [structure]

[0020] Figure 1 1 is a schematic configuration diagram of an in-vehicle system 1 according to an embodiment of the present disclosure. Figure 1 The illustrated in-vehicle system 1 includes a main battery (main BATT) 10 , a redundant power supply system 20 , and a brake system 30 .

[0021] The vehicle-mounted system 1 according to this embodiment can be installed in a vehicle equipped with a load (system, actuator, etc.) requiring a redundant power supply configuration. Hereinafter, this embodiment will be described using a vehicle equipped with a brake system 30 requiring a redundant power supply configuration as an example.

[0022] (1) Main battery

[0023] The main battery 10 is a secondary battery such as a lithium-ion battery configured to be chargeable and dischargeable, and can supply electric power to loads mounted on the vehicle, such as the redundant power supply system 20 and the brake system 30 .

[0024] (2) Redundant power supply system

[0025] The redundant power supply system 20 is a system for supplying backup power to the brake system 30 when an abnormality occurs in the power supply from the main battery 10 to the brake system 30 due to a power failure or the like. The redundant power supply system 20 includes a DC-DC converter (DDC) 21, a slave battery (slave BATT) 22, a semiconductor relay 23, and a control unit 24.

[0026] The DC-DC converter 21 is a power converter for converting power input from the main battery 10 into power of a predetermined voltage and outputting the converted power. Based on instructions (such as a voltage command value) from the control unit 24, the DC-DC converter 21 can charge the sub-battery 22 with power supplied from the main battery 10. Furthermore, based on instructions from the control unit 24, the DC-DC converter 21 can supply power (backup power) stored in the sub-battery 22 to the brake system 30 via the semiconductor relay 23.

[0027] The sub-battery 22 is a chargeable and dischargeable secondary battery such as a lithium-ion battery or a storage element such as a capacitor. The sub-battery 22 is connected to the DC-DC converter 21 so as to charge the main battery 10 and discharge its stored power to the brake system 30 .

[0028] The semiconductor relay 23 is a relay using, for example, a field-effect transistor (MOSFET). It is inserted between the DC-DC converter 21 and the brake system 30, with the parasitic diode (body diode) oriented to rectify the current from the brake system 30 to the DC-DC converter 21. Specifically, the first terminal of the semiconductor relay 23, which serves as the cathode side of the parasitic diode, is connected to the DC-DC converter 21, while the second terminal of the semiconductor relay 23, which serves as the anode side of the parasitic diode, is connected to the brake system 30. The semiconductor relay 23 switches between electrically conducting and disconnecting states based on instructions from the control unit 24 (or another control unit (not shown)).

[0029] The control unit 24 controls the charging and discharging of the secondary battery 22 and the output voltage Vpwb of the DCDC converter 21 by instructing the DCDC converter 21 to operate. This control is performed based on, for example, a wake-up signal (described later) transmitted from the braking system 30. The control unit 24 can also control the switching between the on and off states of the semiconductor relay 23. The control unit 24 is comprised of, for example, a microcontroller including a processor, memory, and input / output interfaces. The processor reads and executes programs stored in the memory to implement its specified functions. While the control unit 24 is included in the redundant power supply system 20, it can also be configured as a component other than the redundant power supply system 20.

[0030] (3) Braking system

[0031] The brake system 30 is a control system that operates with power from the main battery 10 or the sub-battery 22 and generates braking force on the vehicle via a brake actuator (BRK_ACT) of the vehicle using a brake mechanism (not shown). The brake system 30 includes a voltage monitor 31 and a diagnostic unit 32.

[0032] The voltage monitor 31 is configured to monitor the voltage Vin appearing at the input terminal of the monitoring brake system 30 to which backup power is supplied from the redundant power supply system 20, that is, the output voltage Vout of the redundant power supply system 20. The voltage monitor 31 may include a detection element such as a voltage sensor.

[0033] The diagnostic unit 32 is a structure for performing diagnostic processing to diagnose the state of the brake system 30. The diagnostic unit 32 diagnoses whether the brake actuator is operating, for example, and whether the brake system 30 is operating normally. More specifically, the diagnostic unit 32 determines whether the voltage Vin value (in the case of the brake system 30) detected by the voltage monitor 31 at the input terminal is normal. Figure 1 In the example, the voltage drop due to diode D31 and resistor R30 is subtracted from the voltage of main battery 10. For example, the diagnostic process for brake system 30 begins when the vehicle's ignition is turned on (ignition started), a vehicle door is opened, or the brake pedal is depressed.

[0034] When performing diagnostic processing on the brake system 30, the diagnostic unit 32 of this embodiment notifies the redundant power supply system 20 that the diagnosis of the brake system 30 has been initiated. An example of notification of the start of diagnosis is the transmission of a wake-up signal to activate the redundant power supply system 20. This wake-up signal is preferably transmitted from the brake system 30 to the redundant power supply system 20 via a dedicated line (a direct line) rather than via an on-board network such as a CAN.

[0035] Furthermore, part or all of the components of the brake system 30 can typically be configured as an electronic control unit (e.g., BRK_ECU) including a processor, memory, and input / output interfaces. The electronic control unit implements the aforementioned functions by reading and executing programs stored in the memory. Furthermore, while the diagnostic unit 32 is included in the brake system 30, it may also be configured as a component outside of the brake system 30.

[0036] [control]

[0037] Next, refer to Figure 2 Control executed by the in-vehicle system 1 according to this embodiment will be described. Figure 2 This is a flowchart illustrating the procedure of the diagnostic processing of the brake system 30 executed by the in-vehicle system 1 .

[0038] If you open the vehicle door or step on the brake pedal, the Figure 2 A diagnostic process for the brake system 30 is shown.

[0039] (Step S201)

[0040] The in-vehicle system 1 activates the brake system 30. This activation is achieved by connecting the main battery 10 to the power line of the brake system 30 (applying the voltage of the main battery 10 to the power line). If the brake system 30 is activated, the process proceeds to step S202.

[0041] (Step S202)

[0042] The diagnostic unit 32 of the brake system 30 notifies the redundant power supply system 20 of the start of diagnostic processing for the brake system 30 (diagnostic start notification). In this embodiment, the diagnostic unit 32 notifies the redundant power supply system 20 of the start of diagnostic processing by sending a wake-up signal (wake-up signal: ON) to activate the redundant power supply system 20. Furthermore, the diagnostic unit 32 performs diagnostic processing for the brake system 30 simultaneously with the notification of the start of diagnostic processing. By sending the wake-up signal to the redundant power supply system 20 via a dedicated line (a direct line), the brake system 30 and the redundant power supply system 20 can be activated almost simultaneously. Once the start of diagnostic processing for the brake system 30 is notified to the redundant power supply system 20, the process proceeds to step S203.

[0043] (Step S203)

[0044] The in-vehicle system 1 activates the redundant power supply system 20. This activation is achieved by starting the DC-DC converter 21 of the redundant power supply system 20 (outputting the output voltage Vpwb). After the redundant power supply system 20 is activated, the control unit 24 of the redundant power supply system 20 controls the DC-DC converter 21 so that the output voltage Vpwb of the DC-DC converter 21 is higher than the voltage Vin at the input terminal of the brake system 30. An example of this control is control (discharge control) in which the semiconductor relay 23, while in the disconnected state, discharges the power of the sub-battery 22 (or the power of the main battery 10) toward the resistor R20 and capacitor C20, thereby increasing the output voltage Vpwb. This voltage control prevents current from flowing from the brake system 30 to the redundant power supply system 20 via the parasitic diode of the semiconductor relay 23. Once the redundant power supply system 20 is activated and the output voltage Vpwb of the DC-DC converter 21 is controlled, the process proceeds to step S204.

[0045] (Step S204)

[0046] The diagnostic unit 32 of the brake system 30 determines whether the diagnostic processing of the brake system 30 is completed. Through this diagnostic processing, at least a normal diagnostic result or an abnormal diagnostic result of the brake system 30 is obtained. This diagnosis is performed based on the detected voltage value of the voltage monitor 31 as described above. When the diagnostic processing of the brake system 30 is completed (step S204, yes), the process proceeds to step S205. On the other hand, when the diagnostic processing of the brake system 30 is not completed (step S204, no), the completion of the diagnostic processing is again determined based on step S204.

[0047] (Step S205)

[0048] The in-vehicle system 1 determines whether the vehicle's ignition is on (ignition on). If the ignition is on (ignition on) (step S205, yes), the process proceeds to step S206. On the other hand, if the ignition is not on (ignition off) (step S205, no), the process proceeds to step S208.

[0049] (Step S206)

[0050] The diagnostic unit 32 of the brake system 30 notifies the redundant power supply system 20 that the diagnostic process for the brake system 30 has ended (diagnosis completion notification). In this embodiment, the diagnostic unit 32 notifies the redundant power supply system 20 of the completion of the diagnostic process by sending a wakeup signal (wakeup signal: OFF) to the redundant power supply system 20 to shut down (sleep) the redundant power supply system 20. Once the redundant power supply system 20 has been notified of the completion of the diagnostic process for the brake system 30, the process proceeds to step S207.

[0051] (Step S207)

[0052] The in-vehicle system 1 performs actions based on the diagnostic results of the diagnostic unit 32 of the brake system 30. For example, if the diagnosis result indicates that the brake system 30 is normal, the in-vehicle system 1 activates each vehicle system and operates them normally. On the other hand, if the diagnosis result indicates that the brake system 30 is abnormal, the in-vehicle system 1 activates only specific vehicle systems and performs actions (such as warning displays and sounds) to warn that an abnormality has occurred in the brake system 30. Once the actions based on the diagnostic results are performed, the diagnostic process for the brake system 30 is completed.

[0053] (Step S208)

[0054] The onboard system 1 determines whether a first time has elapsed since the braking system 30 was activated. This determination is made to avoid excessive and continuous activation of the braking system 30 and the redundant power supply system 20, which would result in increased power consumption. Therefore, the first time can be set to a predetermined time that allows the system to consume less power. If it is determined that the first time has elapsed since the braking system 30 was activated (step S208, yes), the process proceeds to step S209. On the other hand, if it is determined that the first time has not elapsed since the braking system 30 was activated (step S208, no), the process proceeds to step S205.

[0055] (Step S209)

[0056] The in-vehicle system 1 stops the brake system 30. This is done by disconnecting the power line between the main battery 10 and the brake system 30 (preventing the voltage of the main battery 10 from being applied to the power line). When the brake system 30 stops, the process proceeds to step S210.

[0057] (Step S210)

[0058] The in-vehicle system 1 stops the redundant power supply system 20. This is done by stopping the operation of the DCDC converter 21 of the redundant power supply system 20 (not outputting the output voltage Vpwb). When the redundant power supply system 20 stops, the diagnostic process of the brake system 30 ends.

[0059] <Function and Effect>

[0060] As described above, according to the in-vehicle system 1 according to one embodiment of the present disclosure, in a configuration in which a single semiconductor relay 23 is inserted between the sub-battery 22 and the brake system 30, when the brake system 30 performs a self-diagnosis, the redundant power supply system 20, which controls the sub-battery 22, is notified of the start of the diagnostic process. Upon receiving the notification of the start of the diagnostic process, the redundant power supply system 20 controls the DC-DC converter 21 to discharge the sub-battery 22 so that the voltage Vpwb at the first terminal of the semiconductor relay 23 on the sub-battery 22 (DCDC converter 21) side is higher than the voltage Vout at the second terminal on the brake system 30 side.

[0061] This control makes the voltage across the semiconductor relay 23 higher on the secondary battery 22 (DCDC converter 21) side than on the brake system 30 side. This prevents current from flowing from the brake system 30 to the redundant power supply system 20 via the parasitic diode of the semiconductor relay 23. Consequently, accurate self-diagnosis results for the brake system 30 can be obtained.

[0062] The above describes an embodiment of the technology disclosed herein, but the present disclosure can be understood as an in-vehicle system, a control method executed by an in-vehicle system having a processor and a memory, a control program for executing the control method, a non-temporary storage medium readable by a computer storing the control program, and a vehicle equipped with the in-vehicle system.

[0063] The vehicle-mounted system of the present disclosure can be used for a vehicle or the like equipped with a load requiring a redundant power supply structure.

Claims

1. A vehicle-mounted system, mounted on a vehicle, characterized in that: The vehicle-mounted system includes: Main battery; Secondary battery; a brake system connected to the main battery and to the slave battery via a semiconductor relay, the main battery configured to supply power to the brake system, and the slave battery configured to supply power to the brake system; a diagnosis unit configured to diagnose the presence or absence of an abnormality in the brake system; and a control unit configured to control charging and discharging of the sub-battery, The diagnosis unit is configured to notify the control unit of the start of diagnosis when the diagnosis of the brake system is started. The control unit is configured to start discharging control of the sub-battery based on the diagnosis notified from the diagnosis unit. The control unit is configured to make the voltage of the first terminal of the semiconductor relay connected to the sub-battery higher than the voltage of the second terminal of the semiconductor relay connected to the brake system based on the diagnosis start notified by the diagnosis unit.

2. The vehicle-mounted system according to claim 1, wherein: The diagnosis unit is configured to: notify the control unit of the completion of the diagnosis when the diagnosis of the brake system is completed; and The control unit is configured to terminate the discharge control of the sub-battery based on the termination of the diagnosis notified from the diagnosis unit.

3. The vehicle-mounted system according to claim 2, characterized in that: The diagnosis unit is configured to notify the control unit of the completion of the diagnosis after the ignition of the vehicle is turned on.

4. The vehicle-mounted system according to any one of claims 1 to 3, characterized in that: The semiconductor relay includes a parasitic diode that rectifies current from the second terminal toward the first terminal.

5. A vehicle, characterized in that: The vehicle includes an onboard system, and the onboard system includes: Main battery; Secondary battery; a brake system connected to the main battery and to the slave battery via a semiconductor relay, the main battery configured to supply power to the brake system, and the slave battery configured to supply power to the brake system; a diagnosis unit that diagnoses whether there is an abnormality in the brake system; and a control unit that controls the charging and discharging of the secondary battery, The diagnosis unit is configured to notify the control unit of the start of diagnosis when the diagnosis of the brake system is started. The control unit is configured to start discharging control of the sub-battery based on the diagnosis notified from the diagnosis unit. The control unit is configured to make the voltage of the first terminal of the semiconductor relay connected to the sub-battery higher than the voltage of the second terminal of the semiconductor relay connected to the brake system based on the diagnosis start notified by the diagnosis unit.

6. A vehicle-mounted system, mounted on a vehicle, characterized in that: The vehicle-mounted system includes: Main battery; secondary battery; a brake system connected to the main battery and to the slave battery via a semiconductor relay, the main battery configured to supply power to the brake system, and the slave battery configured to supply power to the brake system; a first processor for diagnosing whether there is an abnormality in the brake system; a second processor that controls charging and discharging of the secondary battery; and a converter located between the secondary battery and the semiconductor relay, The second processor is configured to issue a command to the converter based on the diagnosis start signal of the brake system from the first processor. The second processor, upon receiving the diagnosis start signal from the first processor, uses the converter to discharge the power of the sub-battery toward the semiconductor relay. The second processor is configured to increase the voltage of the first terminal of the semiconductor relay connected to the sub-battery higher than the voltage of the second terminal of the semiconductor relay connected to the brake system based on the diagnosis start signal notified from the first processor.

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