In-vehicle control device

Abstract

The in-vehicle control device (10) is included in an in-vehicle system (100), and is provided with: a power line (80) that supplies power from a power supply unit (90) to a load (91); a relay (11) provided in the power line (80); and a cutting unit (12) provided in the power line (80). The in-vehicle control device (10) is provided with a control unit (14) that controls the cutoff unit (12). The cut-off unit (12) switches from a permitted state in which the supply of power from the power supply unit (90) side to the load (91) side is permitted, to a cut-off state in which the supply of power from the power supply unit (90) side to the load (91) side is cut off. When the value of the current flowing through the relay (11) exceeds a threshold value, the control unit (14) switches the cut-off unit (12) to the cut-off state on the basis of the elapsed time since the threshold value has been exceeded and the value of the current after the threshold value has been exceeded.

Description

Technical Field

[0001] The present disclosure relates to a vehicle-mounted control device. Background Art

[0002] A load circuit for supplying electric power to a load is disclosed in Background Art of Patent Document 1. The load circuit includes a battery and a relay (semiconductor switch) provided between the battery and the load, and the drive and stop of the load are switched by turning the relay on and off.

[0003] Prior art literature Patent Literature Patent Document 1: Japanese Patent Application Publication No. 2015-35951 Summary of the invention

[0004] Problems to be solved by the invention

[0005] If the overcurrent continues to flow through the relay, the relay may cause abnormalities such as smoke. Therefore, it is considered to provide a cut-off unit separately from the relay, and cut off the power line when the current exceeding the threshold value continues to flow for a certain period of time, thereby preventing the above-mentioned abnormality from occurring. However, the time until the above-mentioned abnormality occurs varies according to the current value after exceeding the threshold value. Therefore, it is preferable to cut off the power line in consideration of the time elapsed since the current value flowing through the relay exceeded the threshold value and the current value after exceeding the threshold value.

[0006] An object of the present disclosure is to provide a technology capable of switching a cutoff unit to a cutoff state in consideration of the time elapsed since a current value flowing through a relay exceeded a threshold value and the current value after exceeding the threshold value.

[0007] Technical solutions to solve problems

[0008] The vehicle-mounted control device disclosed in the present invention is included in a vehicle-mounted system, and the vehicle-mounted control device comprises: a power line for supplying power from a power supply unit to a load; a relay provided in the power line; and a disconnection unit provided in the power line, wherein: The vehicle-mounted control device includes a control unit that controls the cutoff unit. The cut-off unit switches from a permitted state to a cut-off state, wherein the permitted state permits the supply of electric power from the power supply unit to the load unit, and the cut-off state cuts off the supply of electric power from the power supply unit to the load unit. When the value of the current flowing through the relay exceeds a threshold value, the control unit switches the cutoff unit to the cutoff state based on an elapsed time from when the current value exceeds the threshold value and the current value after exceeding the threshold value.

[0009] Effects of the Invention

[0010] The technology according to the present disclosure can switch the cutoff unit to the cutoff state in consideration of the time elapsed since the current value flowing through the relay exceeded the threshold value and the current value after exceeding the threshold value. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 1 is a diagram schematically showing a configuration of an in-vehicle system including the in-vehicle control device according to the first embodiment. Figure 2 It is an explanatory diagram showing the graphs G1 and G2. Figure 3 It is an explanatory diagram showing the corresponding data DA. Figure 4 It is an explanatory diagram showing the corresponding data DB. Figure 5 It is an explanatory diagram showing the corresponding data DC. Figure 6 It is an explanatory diagram showing TC correspondence data DD. Figure 7 This is a flowchart showing the flow of processing performed by the control unit. DETAILED DESCRIPTION

[0012] [Description of Embodiments of the Present Disclosure]

[0013] Hereinafter, embodiments of the present disclosure will be listed and illustrated.

[0014] [1] A vehicle-mounted control device included in a vehicle-mounted system, the vehicle-mounted control device comprising: a power line for supplying power from a power supply unit to a load; a relay provided on the power line; and a disconnection unit provided on the power line, wherein: The vehicle-mounted control device includes a control unit that controls the cutoff unit. The cut-off unit switches from a permitted state to a cut-off state, wherein the permitted state permits the supply of electric power from the power supply unit to the load unit, and the cut-off state cuts off the supply of electric power from the power supply unit to the load unit. When the value of the current flowing through the relay exceeds a threshold value, the control unit switches the cutoff unit to the cutoff state based on an elapsed time from when the current value exceeds the threshold value and the current value after exceeding the threshold value.

[0015] The vehicle-mounted control device switches the cut-off portion to the cut-off state based on the time elapsed since the current value flowing through the relay exceeds the threshold value and the current value after exceeding the threshold value. That is, the vehicle-mounted control device can switch the cut-off portion to the cut-off state in consideration of the time elapsed since the current value flowing through the relay exceeds the threshold value and the current value after exceeding the threshold value.

[0016] [2] In the vehicle-mounted control device described in [1], the threshold value is a value smaller than the maximum rated current of the vehicle.

[0017] The vehicle-mounted control device can switch the cutoff unit to the cutoff state when the value of the current flowing through the relay exceeds a threshold value set to a value smaller than the maximum rated current of the vehicle.

[0018] [3] In the vehicle-mounted control device described in [1], the threshold value is a value smaller than a maximum cut-off current, and the maximum cut-off current is a maximum current at which the relay can be switched from an on state to an off state.

[0019] The vehicle-mounted control device can switch the cutoff unit to the cutoff state when the value of the current flowing through the relay exceeds a threshold value set to a value smaller than the maximum cutoff current.

[0020] [4] In the vehicle-mounted control device described in any one of [1] to [3], when the current value exceeds the threshold value, the control unit determines whether the time integral value of the current value since exceeding the threshold value exceeds the corresponding value corresponding to the elapsed time, and switches the cut-off unit to the cut-off state when it is determined that the current value exceeds the corresponding value.

[0021] The vehicle-mounted control device can switch the cutoff unit to the cutoff state when the time-integrated value of the current value accumulates to an extent exceeding a corresponding value corresponding to the elapsed time.

[0022] [5] In the vehicle-mounted control device described in any one of [1] to [3], when the current value exceeds the threshold value, the control unit determines whether the time integral value of the square of the current value since exceeding the threshold value exceeds a corresponding value corresponding to the elapsed time, and switches the cut-off unit to the cut-off state when it is determined that the corresponding value is exceeded.

[0023] The vehicle-mounted control device can switch the cutoff unit to the cutoff state when the time-integrated value of the square of the current value accumulates to an extent exceeding a corresponding value corresponding to the elapsed time.

[0024] [6] In the vehicle-mounted control device described in any one of [1] to [5], a cut-off upper limit value is preset, the cut-off upper limit value is greater than the threshold value and less than a maximum current that can be passed, the maximum current that can be passed is a maximum current that can maintain the relay in an on state, When the current value exceeds the cutoff upper limit value, the control unit switches the cutoff unit to the cutoff state regardless of the elapsed time.

[0025] When the current value flowing through the relay exceeds the cutoff upper limit value, the vehicle-mounted control device switches the cutoff unit to the cutoff state regardless of the elapsed time, thereby making it easy to switch the cutoff unit to the cutoff state before the relay smokes or catches fire.

[0026] [7] In the vehicle-mounted control device described in [6], the maximum current that can be passed is smaller than a saturation current that flows through the power line when a ground fault occurs in the power line, The cutoff upper limit value is set so that the cutoff unit switches to the cutoff state before the current value reaches the saturation current in consideration of a time lag from when it is determined that the current value exceeds the cutoff upper limit value until the cutoff unit switches to the cutoff state.

[0027] The vehicle-mounted control device can switch the cutoff portion to the cutoff state before the current value flowing through the relay reaches the saturation current.

[0028] [8] In the vehicle-mounted control device described in [6], the cut-off upper limit value is set so that, taking into account the time lag from when it is determined that the current value exceeds the cut-off upper limit value to when the cut-off unit switches to the cut-off state, the cut-off unit switches to the cut-off state before the current value reaches the maximum current that can be passed.

[0029] The vehicle-mounted control device can switch the cutoff section to the cutoff state before the current value flowing through the relay reaches the maximum current that can be energized. Therefore, the vehicle-mounted control device can prevent the relay from being unable to maintain the on state due to a current exceeding the maximum current that can be energized flowing through the relay.

[0030] [9] In the vehicle-mounted control device according to any one of [1] to [8], the relay is controlled by a second control unit different from the control unit, When the control unit determines that the second control unit controls the relay to be in the off state in a state where the current value exceeds the threshold value, the control unit switches the cutoff unit to the cutoff state regardless of the elapsed time.

[0031] It is also assumed that the second control unit intends to switch the relay to the disconnected state, but does not switch to the disconnected state due to a relay failure, etc. Even if such a situation occurs, the vehicle-mounted control device can more reliably cut off the current flowing through the power line by switching the disconnection unit to the disconnection state when the second control unit intends to switch the relay to the disconnected state.

[0032] [Details of the embodiments of the present disclosure]

[0033] <First Embodiment>

[0034] exist Figure 1 2 shows an in-vehicle system 100 including the in-vehicle control device 10 . The in-vehicle system 100 is a system mounted on a vehicle. The in-vehicle system 100 includes a power supply unit 90 , a load 91 , and a power line 80 .

[0035] The power supply unit 90 is, for example, a DC power supply that generates a DC voltage, such as a storage battery. The storage battery is, for example, a lead acid battery, a lithium ion storage battery, etc. The load 91 is an electronic component provided in the vehicle. The load 91 is, for example, an electric component, an ECU, an ADAS target component, etc. The power line 80 is provided between the power supply unit 90 and the load 91. The power line 80 supplies power from the power supply unit 90 to the load 91. One end of the power line 80 is electrically connected to the power supply unit 90, and the other end is electrically connected to the load 91.

[0036] The vehicle-mounted control device 10 includes a relay 11 , a disconnection unit 12 , a current detection unit 13 , a control unit 14 , and a second control unit 15 .

[0037] The relay 11 is provided in the power line 80. When the relay 11 is in the on state, the power line 80 and the load 91 are in the energized state. When the relay 11 is in the off state, the power line 80 and the load 91 are in the non-energized state. The relay 11 is controlled by the second control unit 15. In the present embodiment, the relay 11 is configured as an electromagnetic relay having contacts that are operated by electromagnetic force.

[0038] The cut-off unit 12 is provided on the power line 80. The cut-off unit 12 switches from the permitted state to the cut-off state, wherein the permitted state permits the supply of electric power from the power supply unit 90 side to the load 91 side, and the cut-off state cuts off the supply of electric power from the power supply unit 90 side to the load 91 side. The cut-off unit 12 may be a structure that can be restored to the permitted state after being in the cut-off state, or a structure that cannot be restored to the permitted state. The cut-off unit 12 may be configured, for example, as a pyrotechnic circuit breaker, a semiconductor switch, an electromagnetic fuse, or the like. The pyrotechnic circuit breaker is a circuit breaker that physically cuts off the power line 80 according to an input drive signal, such as a pyrotechnic fuse (PYROFUSE (registered trademark)). The cut-off unit 12 is controlled by the control unit 14.

[0039] The current detection unit 13 is configured as, for example, a well-known current sensor. The current detection unit 13 detects the current flowing through the relay 11. The current detection unit 13 outputs a signal that can identify the detection value. The signal is input to the control unit 14 and the second control unit 15, respectively.

[0040] The control unit 14 controls the cutoff unit 12 . The control unit 14 is configured as, for example, an MCU (Micro Controller Unit). The control unit 14 is configured as a device different from the second control unit 15 . The control unit 14 detects the current value flowing through the relay 11 based on the signal output from the current detection unit 13 .

[0041] When the current value flowing through the relay 11 exceeds the threshold value A, the control unit 14 switches the cut-off unit 12 to the cut-off state based on the elapsed time EA from exceeding the threshold value A and the current value after exceeding the threshold value A. The threshold value A is a value smaller than the maximum rated current IA of the vehicle. For example, the battery management system that manages the power supply unit 90 (specifically, the battery) treats the current exceeding the maximum rated current IA as overflow. For example, the battery management system treats the current exceeding the maximum rated current IA as the maximum rated current IA in the calculation of SOC (State Of Charge). For example, the current consumption of the load 91 is limited to not exceed the maximum rated current IA.

[0042] When the current value flowing through the relay 11 exceeds the threshold value A, the control unit 14 determines whether the time integral value ZA of the current value since the threshold value A has exceeded the corresponding value CA corresponding to the elapsed time EA, and when it is determined that the corresponding value CA has been exceeded, the cut-off unit 12 is switched to the cut-off state. The control unit 14 pre-stores the corresponding data DA indicating the corresponding relationship between the elapsed time EA and the corresponding value CA. The corresponding data DA may be a function indicating the corresponding relationship between the elapsed time EA and the corresponding value CA, or may be table data indicating the corresponding relationship between the elapsed time EA and the corresponding value CA. The corresponding data DA is set to have Figure 2 The graph G1 shows the cut-off characteristics. The graph G1 shows the time until the cut-off when the current of the current value continues to flow for each current value within the predetermined current value range. The graph G1 shows the characteristics that the larger the current value, the shorter the cut-off time.

[0043] When the current value flowing through the relay 11 exceeds the threshold value A, the control unit 14 repeatedly calculates the time integral value ZA of the current value since the current value exceeded the threshold value A. Figure 3 As shown, the control unit 14 first calculates ZA1 as the time integral value ZA. In the next cycle, the control unit 14 adds ZA2 to the time integral value ZA calculated in the previous cycle and uses it as the new time integral value ZA. The control unit 14 repeatedly calculates the time integral value ZA by repeatedly performing such processing. The control unit 14 uses the corresponding data DA to derive the corresponding value CA corresponding to the elapsed time EA. The control unit 14 repeatedly determines whether the time integral value ZA exceeds the corresponding value CA. Figure 3In the example shown, the time-integrated value ZA of the sixth cycle including ZA6 exceeds the corresponding value CA. When the control unit 14 determines that the time-integrated value ZA exceeds the corresponding value CA, the control unit 14 switches the cutoff unit 12 to the cutoff state.

[0044] The time integrated value ZA may be reset to 0 when the first reset condition is satisfied. The first reset condition may be that a certain time has passed since the current value flowing through the relay 11 exceeded the threshold value A, or that the current value flowing through the relay 11 has fallen below the threshold value A, or other conditions.

[0045] When the current value flowing through the relay 11 exceeds the threshold value B, the control unit 14 switches the cut-off unit 12 to the cut-off state based on the elapsed time from exceeding the threshold value B and the current value after exceeding the threshold value B. The threshold value B is a value smaller than the maximum cut-off current IB. In the present embodiment, the threshold value B is the same as the threshold value A, but may be greater than the threshold value A or less than the threshold value A. The maximum cut-off current IB is the maximum current at which the relay 11 can be switched from the on state to the off state.

[0046] When the current value flowing through the relay 11 exceeds the threshold value B, the control unit 14 determines whether the time integral value ZB of the current value since the threshold value B exceeds the corresponding value CB corresponding to the elapsed time EB, and switches the cut-off unit 12 to the cut-off state when it is determined that the corresponding value CB is exceeded. The control unit 14 pre-stores the corresponding data DB indicating the corresponding relationship between the elapsed time EB and the corresponding value CB. The corresponding data DB may be a function indicating the corresponding relationship between the elapsed time EB and the corresponding value CB, or may be table data indicating the corresponding relationship between the elapsed time EB and the corresponding value CB. The corresponding data DB is set to have Figure 2 The curve G1 represents the cutting characteristics.

[0047] When the current value flowing through the relay 11 exceeds the threshold value B, the control unit 14 repeatedly calculates the time integral value ZB of the current value since the current value exceeded the threshold value B. Figure 4 As shown, the control unit 14 first calculates ZB1 as the time integral value ZB. In the next cycle, the control unit 14 adds ZB2 to the time integral value ZB calculated in the previous cycle and uses it as the new time integral value ZB. The control unit 14 repeatedly calculates the time integral value ZB by repeatedly performing such processing. The control unit 14 uses the corresponding data DB to derive the corresponding value CB corresponding to the elapsed time EB. The control unit 14 repeatedly determines whether the time integral value ZB exceeds the corresponding value CB. Figure 4In the example shown, the time-integrated value ZB of the sixth cycle including ZB6 exceeds the corresponding value CB. When the control unit 14 determines that the time-integrated value ZB exceeds the corresponding value CB, the control unit 14 switches the cutoff unit 12 to the cutoff state.

[0048] The time integrated value ZB may be reset to 0 when the second reset condition is satisfied. The second reset condition may be that a certain time has passed since the current value flowing through the relay 11 exceeded the threshold value B, or that the current value flowing through the relay 11 has fallen below the threshold value B, or other conditions.

[0049] The second control unit 15 controls the relay 11. The second control unit 15 is configured as, for example, an MCU (Micro Controller Unit). The second control unit 15 is configured as a device different from the control unit 14. The second control unit 15 switches the relay 11 to the on state when a predetermined start condition is satisfied. The start condition is, for example, that the start switch of the vehicle is switched to the on state. The start switch is, for example, an ignition switch in an engine vehicle, a power switch in an electric vehicle, etc. The second control unit 15, for example, receives a signal indicating the on / off state of the start switch of the vehicle, thereby identifying the on / off state of the start switch. The second control unit 15 switches the relay 11 to the off state when a predetermined stop condition is satisfied. The stop condition is, for example, that the start switch of the vehicle is switched to the off state. The second control unit 15 switches the relay 11 to the off state when a predetermined disconnection condition is satisfied. The disconnection condition is, for example, a condition that can be satisfied based on the current value flowing through the relay 11. The condition that can be satisfied based on the current value flowing through the relay 11 is, for example, a condition that the current value flowing through the relay 11 exceeds a reference value. The second control unit 15 detects the value of the current flowing through the relay 11 based on the signal output from the current detection unit 13 .

[0050] When the current value flowing through the relay 11 exceeds the reference value, the second control unit 15 switches the relay 11 to the OFF state based on the elapsed time EC from exceeding the reference value and the current value after exceeding the reference value.

[0051] When the current value flowing through the relay 11 exceeds the reference value, the second control unit 15 determines whether the time integral value ZC of the current value since it exceeds the reference value exceeds the corresponding value CC corresponding to the elapsed time EC. When it is determined that the corresponding value CC is exceeded, the relay 11 is switched to the disconnected state. The second control unit 15 pre-stores corresponding data DC indicating the corresponding relationship between the elapsed time EC and the corresponding value CC. The corresponding data DC may be a function indicating the corresponding relationship between the elapsed time EC and the corresponding value CC, or may be table data indicating the corresponding relationship between the elapsed time EC and the corresponding value CC. The corresponding data DC is set to have Figure 2 The curve G2 shows the cut-off characteristics. The curve G2 shows the time until the cut-off when the current of the current value continues to flow for each current value in the specified current value range (specifically, the current value range smaller than the lower limit value of the current value range in the curve G1). The curve G2 shows the characteristics that the larger the current value, the shorter the time of cut-off.

[0052] When the current value flowing through the relay 11 exceeds the reference value, the second control unit 15 repeatedly calculates the time integral value ZC of the current value since the current value exceeded the reference value. Figure 5 As shown, the second control unit 15 first calculates ZC1 as the time integral value ZC. In the next cycle, the second control unit 15 adds ZC2 to the time integral value ZC calculated in the previous cycle and uses it as a new time integral value ZC. The second control unit 15 repeatedly calculates the time integral value ZC by repeatedly performing such processing. The second control unit 15 uses the corresponding data DC to derive the corresponding value CC corresponding to the elapsed time EC. The second control unit 15 repeatedly determines whether the time integral value ZC exceeds the corresponding value CC. Figure 5 In the example shown, the time-integrated value ZC of the ninth cycle including ZC9 exceeds the corresponding value CC. When determining that the time-integrated value ZC exceeds the corresponding value CC, the second control unit 15 switches the cutoff unit 12 to the cutoff state.

[0053] Furthermore, the time integrated value ZC may be reset to 0 when the third reset condition is satisfied. The third reset condition may be that a certain time has passed since the current value flowing through the relay 11 exceeded the reference value, or that the current value flowing through the relay 11 has fallen below the reference value, or other conditions.

[0054] When the current value flowing through the relay 11 exceeds the preset cut-off upper limit value ID, the control unit 14 switches the cut-off unit 12 to the cut-off state regardless of the above-mentioned elapsed time EA and EB. The cut-off upper limit value ID is greater than the threshold values ​​A and B. The cut-off upper limit value ID is greater than the maximum cut-off current IB. The cut-off upper limit value ID is less than the maximum energizable current IC. The maximum energizable current IC is the maximum current that the relay 11 can maintain in the on state. As described above, the relay 11 is an electromagnetic relay. When current flows through the electromagnetic relay, an electromagnetic repulsive force is generated in the electromagnetic relay to change from the on state to the off state. The electromagnetic repulsive force increases in accordance with the increase in the magnitude of the current flowing into the electromagnetic relay. When the current flowing into the electromagnetic relay is greater than the maximum energizable current IC, the electromagnetic repulsive force becomes greater than the force that maintains the electromagnetic relay in the on state, and the electromagnetic relay changes to the off state. When the electromagnetic relay changes to the off state, there is a possibility that an arc is generated in the electromagnetic relay and the electromagnetic relay fails. Therefore, when the current value flowing through relay 11 exceeds cutoff upper limit value ID set to a value smaller than maximum energizable current IC, control unit 14 switches cutoff unit 12 to the cutoff state regardless of the elapsed times EA and EB.

[0055] The above-mentioned maximum current IC that can be passed is smaller than the saturation current IS that flows through the power line 80 when a ground fault occurs in the power line 80. The saturation current IS is, for example, a saturation current when a ground fault occurs in the path between the relay 11 and the load 91 when the power supply unit 90 is fully charged in a state where the vehicle-mounted system 100 is not degraded. The cut-off upper limit value ID is set so that the cut-off unit 12 switches to the cut-off state before the current value flowing through the relay 11 reaches the saturation current IS, taking into account the time lag TL from when it is determined that the current value flowing through the relay 11 exceeds the cut-off upper limit value ID to when the cut-off unit 12 switches to the cut-off state.

[0056] The cutoff upper limit value ID is based on, for example, the time lag TL and TC corresponding data DD (see Figure 6 ) is set, and the TC corresponding data DD represents the corresponding relationship between the elapsed time from the occurrence of the ground fault and the current value flowing through the relay 11.

[0057] The time lag TL is generated based on the time from when the control unit 14 determines that the cutoff upper limit value ID is exceeded to when the control of switching the cutoff unit 12 to the cutoff state is started, and the time from when the control of switching the cutoff unit 12 to the cutoff state is started to when the cutoff unit 12 is switched to the cutoff state. The time lag TL is obtained, for example, based on test results or simulation results.

[0058] The TC correspondence data DD is obtained, for example, from test results or simulation results when a ground fault occurs in the path between the relay 11 and the load 91 while the vehicle-mounted system 100 is not degraded and the power supply unit 90 is fully charged.

[0059] exist Figure 6 In the TC correspondence data DD shown, time T0 is the time when the ground fault occurs. After that, the current value gradually increases with the passage of time. Time T4 is the time when the current value flowing through the relay 11 reaches the saturation current IS.

[0060] The time when the current value flowing through the relay 11 reaches the saturation current IS may be, for example, when the time elapsed from the occurrence of the ground fault becomes three times the time constant τ or when 1 ms has elapsed from the occurrence of the ground fault. The time constant τ is calculated, for example, by the following formula (1).

[0061] Time constant τ = (L1 + L2 + L3) / (R1 + R2 + R3) Formula (1)

[0062] L1 is the internal inductance of the power supply unit 90. L2 is the inductance of the path between the power supply unit 90 and the ground fault location in the power line 80. L3 is the inductance of the ground fault location. R1 is the internal resistance value of the power supply unit 90. R2 is the resistance value of the path between the power supply unit 90 and the ground fault location in the power line 80. R3 is the resistance value of the ground fault location. In addition, L3 and R3 can be changed according to the type of the ground fault, and therefore, for example, can also be set to 0.

[0063] For example, the current value corresponding to time T1 which does not reach time T4 even if time lag TL is considered is set as the cutoff upper limit value ID. That is, time T1 is determined when time T2 after time lag TL becomes earlier than time T4, and the current value corresponding to this time T1 is set as the cutoff upper limit value ID.

[0064] The cut-off upper limit value ID is set so that the cut-off unit 12 switches to the cut-off state before the current value flowing through the relay 11 reaches the maximum current IC, taking into account the time lag TL from when the current value flowing through the relay 11 is determined to exceed the cut-off upper limit value ID to when the cut-off unit 12 switches to the cut-off state. The cut-off upper limit value ID is set, for example, based on the time lag TL and the above-mentioned TC corresponding data DD.

[0065] exist Figure 6In the TC corresponding data DD shown, the time when the current value flowing through the relay 11 reaches the maximum current IC is the time T3. For example, the current value corresponding to the time T1 that does not reach the time T3 even if the time lag TL is taken into account is set as the cut-off upper limit value ID. That is, the time T1 at which the time T2 after the time lag TL becomes earlier than the time T3 is determined, and the current value corresponding to the time T1 is set as the cut-off upper limit value ID.

[0066] The cutoff upper limit value ID is set to a value greater than the maximum current value IE that can flow through the power line 80 in the normal state of the power line 80. The normal state of the power line 80 refers to a state in which the power line 80 has no ground fault, and more specifically, refers to a state in which the voltage value of the power line 80 is greater than or equal to a threshold voltage. The threshold voltage is a value greater than or equal to 0 V. The maximum current value IE that can flow through the power line 80 is, for example, a current that flows through the power line 80 when the load 91 such as a motor in the vehicle is operated to the maximum extent when the power supply unit 90 is fully charged.

[0067] When the current value flowing through the relay 11 exceeds the threshold value A, the control unit 14 switches the disconnection unit 12 to the disconnection state regardless of the elapsed time EA when it is determined that the second control unit 15 controls the relay 11 to the disconnected state. When the current value flowing through the relay 11 exceeds the threshold value B, the control unit 14 switches the disconnection unit 12 to the disconnection state regardless of the elapsed time EB. For example, the second control unit 15 outputs a control signal for controlling the relay 11 to the disconnected state, and outputs a notification signal to the control unit 14. The control unit 14 determines that the second control unit 15 controls the relay 11 to the disconnected state by receiving the notification signal.

[0068] The control unit 14 performs the following operations, for example, when the vehicle start switch is switched to the off state. Figure 7 In step S11, the control unit 14 determines whether the current value flowing through the relay 11 is greater than the threshold value A. When the control unit 14 determines that the current value flowing through the relay 11 is not greater than the threshold value A, in step S14, the control unit 14 determines whether the current value flowing through the relay 11 is greater than the threshold value B. When the control unit 14 determines that the current value flowing through the relay 11 is not greater than the threshold value B, the control unit 14 returns to step S11. When the current value flowing through the relay 11 is normal, the control unit 14 repeatedly performs the processing of step S11 and step S14.

[0069] For example, when a ground fault occurs between the relay 11 and the load 91, the current value flowing through the relay 11 increases. When the control unit 14 determines in step S11 that the current value flowing through the relay 11 is greater than the threshold value A, it starts calculating the time integral value ZA and transfers to step S12. In addition, when the control unit 14 has already calculated the time integral value ZA, it continues calculating the time integral value ZA. In step S12, the control unit 14 determines whether the time integral value ZA is greater than the corresponding value CA corresponding to the time integral value ZA. When the control unit 14 determines that the time integral value ZA is greater than the corresponding value CA, in step S13, the cut-off unit 12 is switched to the cut-off state. When the control unit 14 determines that the time integral value ZA is not greater than the corresponding value CA, it transfers to step S14.

[0070] When the control unit 14 determines in step S14 that the current value flowing through the relay 11 is greater than the threshold value B, the control unit 14 starts calculating the time integral value ZB and transfers to step S15. In addition, when the control unit 14 has already calculated the time integral value ZB, it continues to calculate the time integral value ZB. In step S15, the control unit 14 determines whether the time integral value ZB is greater than the corresponding value CB corresponding to the time integral value ZB. When the control unit 14 determines that the time integral value ZB is not greater than the corresponding value CB, in step S16, the control unit 14 determines whether the control unit 14 controls the relay 11 to the disconnected state. When the control unit 14 determines that the control unit 14 does not control the relay 11 to the disconnected state, in step S17, the control unit 14 determines whether the current value flowing through the relay 11 is greater than the cut-off upper limit value ID. When the control unit 14 determines that the current value flowing through the relay 11 is not greater than the cut-off upper limit value ID, the control unit 14 returns to step S11. That is, when the value of the current flowing through the relay 11 exceeds the threshold value B, the control unit 14 repeats the processing of steps S14, S15, S16, and S17.

[0071] When the control unit 14 determines in step S15 that the time integral value ZB is greater than the corresponding value CB, the cut-off unit 12 is switched to the cut-off state in step S13. When the control unit 14 determines in step S16 that the control unit 14 controls the relay 11 to the disconnected state, the cut-off unit 12 is switched to the cut-off state in step S13. When the control unit 14 determines in step S17 that the current value flowing through the relay 11 is greater than the cut-off upper limit value ID, the cut-off unit 12 is switched to the cut-off state in step S13.

[0072] The following description relates to the effects of the vehicle-mounted control device 10 .

[0073] The vehicle-mounted control device 10 switches the cut-off portion 12 to the cut-off state based on the elapsed time EA from when the current value flowing through the relay 11 exceeds the threshold value A and the current value after exceeding the threshold value A. That is, the vehicle-mounted control device 10 can switch the cut-off portion 12 to the cut-off state in consideration of the elapsed time EA from when the current value flowing through the relay 11 exceeds the threshold value A and the current value after exceeding the threshold value A. In addition, the vehicle-mounted control device 10 can switch the cut-off portion 12 to the cut-off state when the time-integrated value ZA of the current value accumulates to an extent exceeding the corresponding value CA corresponding to the elapsed time EA.

[0074] The vehicle-mounted control device 10 switches the cut-off portion 12 to the cut-off state based on the elapsed time EB from the current value flowing through the relay 11 exceeding the threshold value B and the current value after exceeding the threshold value B. That is, the vehicle-mounted control device 10 can switch the cut-off portion 12 to the cut-off state in consideration of the elapsed time EB from the current value flowing through the relay 11 exceeding the threshold value B and the current value after exceeding the threshold value B. In addition, the vehicle-mounted control device 10 can switch the cut-off portion 12 to the cut-off state when the time-integrated value ZB of the current value accumulates to an extent exceeding the corresponding value CB corresponding to the elapsed time EB.

[0075] When the current value flowing through the relay 11 exceeds the cutoff upper limit value ID, the vehicle-mounted control device 10 switches the cutoff unit 12 to the cutoff state regardless of the elapsed time EB, thereby making it easy to switch the cutoff unit 12 to the cutoff state before the relay 11 cannot maintain the on state.

[0076] The vehicle-mounted control device 10 can switch the cutoff unit 12 to the cutoff state before the current value flowing through the relay 11 reaches the saturation current IS.

[0077] The vehicle-mounted control device 10 can switch the cutoff unit 12 to the cutoff state before the current value flowing through the relay 11 reaches the maximum current IC. Therefore, the vehicle-mounted control device 10 can prevent the relay 11 from being unable to maintain the on state due to the current exceeding the maximum current IC flowing through the relay 11.

[0078] It is also assumed that the second control unit 15 intends to switch the relay 11 to the disconnected state based on the elapsed time EC and the current value, but the relay 11 is not switched to the disconnected state due to a failure of the relay 11. Even if such a situation occurs, the vehicle-mounted control device 10 can more reliably cut off the current flowing through the power line 80 by switching the cutoff unit 12 to the cutoff state when the second control unit 15 intends to switch the relay 11 to the disconnected state.

[0079] <Other embodiments>

[0080] The present disclosure is not limited to the embodiments described in the above description and the accompanying drawings. For example, the features of the above or later embodiments can be combined in all ways within the scope of non-contradiction. In addition, any feature of the above or later embodiments can be omitted as long as it is not explicitly stated as a necessary feature. In addition, the above embodiments can also be changed as follows.

[0081] In the above embodiment, the control unit 14 is configured to determine whether the time integral value ZA of the current value since the current value exceeded the threshold value A exceeds the corresponding value CA corresponding to the elapsed time EA when the current value flowing through the relay 11 exceeds the threshold value A, and switch the cut-off unit 12 to the cut-off state when it is determined that the corresponding value CA is exceeded. In contrast, the control unit 14 may be configured to determine whether the time integral value of the square of the current value since the current value exceeded the threshold value A exceeds the corresponding value corresponding to the elapsed time EA when the current value flowing through the relay 11 exceeds the threshold value A, and switch the cut-off unit 12 to the cut-off state when it is determined that the corresponding value is exceeded. In this case, the vehicle-mounted control device can switch the cut-off unit 12 to the cut-off state when the time integral value of the square of the current value accumulates to a degree exceeding the corresponding value corresponding to the elapsed time EA.

[0082] In the above embodiment, the control unit 14 is configured to determine whether the time integral value ZA of the current value since the current value exceeded the threshold value B exceeds the corresponding value CB corresponding to the elapsed time EB when the current value flowing through the relay 11 exceeds the threshold value B, and switch the cut-off unit 12 to the cut-off state when it is determined that the corresponding value CB is exceeded. In contrast, the control unit 14 may be configured to determine whether the time integral value of the square of the current value since the current value exceeded the threshold value B exceeds the corresponding value corresponding to the elapsed time EB when the current value flowing through the relay 11 exceeds the threshold value B, and switch the cut-off unit 12 to the cut-off state when it is determined that the corresponding value is exceeded. In this case, the vehicle-mounted control device can switch the cut-off unit 12 to the cut-off state when the time integral value of the square of the current value accumulates to a degree exceeding the corresponding value corresponding to the elapsed time EB.

[0083] It is also possible not to set the cutoff upper limit. Figure 7 The process of step S16.

[0084] One of the threshold value A and the threshold value B may be omitted. Figure 7 One of steps S11, S12 and steps S14, S15.

[0085] In the above embodiment, the cutoff upper limit value ID is larger than the maximum cutoff current IB, but may be smaller than the maximum cutoff current IB.

[0086] A fuse may be provided between the power supply unit 90 and the current detection unit 13 .

[0087] The embodiments disclosed herein are illustrative in all aspects and should not be construed as restrictive. The scope of the present invention is not limited to the embodiments disclosed herein, and is intended to include all modifications within the scope of the claims or within the scope equivalent to the claims.

[0088] Description of symbols 10…In-vehicle control device 11…Relay 12…Cutting section 13…Current detection unit 14…Control Unit 15…Second control unit 80…Power lines 90…Power supply 91…Load 100…In-vehicle systems A…Threshold B…Threshold DA…corresponding data DB...corresponding data DC…Corresponding data DD…TC corresponding data EA…Elapsed time EB…Elapsed time EC…Elapsed time G1…Graph G2…Graph IB...Maximum cut-off current IC…Maximum current that can be passed ID…Cut-off upper limit IE…The maximum current that can flow through the power line IS…Saturation current TL…Time Lag ZA…Time integral value ZB…Time integral value ZC…Time integral value.

Claims

1. A vehicle-mounted control device, included in a vehicle-mounted system, the vehicle-mounted control device comprising: a power line for supplying power from a power supply unit to a load; a relay provided on the power line; and a disconnection unit provided on the power line, wherein: The vehicle-mounted control device includes a control unit that controls the cutoff unit. The cut-off unit switches from a permitted state to a cut-off state, wherein the permitted state permits the supply of electric power from the power supply unit to the load unit, and the cut-off state cuts off the supply of electric power from the power supply unit to the load unit. When the value of the current flowing through the relay exceeds a threshold value, the control unit switches the cutoff unit to the cutoff state based on an elapsed time from when the current value exceeds the threshold value and the current value after exceeding the threshold value.

2. The vehicle-mounted control device according to claim 1, wherein: The threshold value is a value smaller than the maximum rated current of the vehicle.

3. The vehicle-mounted control device according to claim 1, wherein: The threshold value is a value smaller than a maximum cuttable current, which is a maximum current at which the relay can be switched from an on state to an off state.

4. The vehicle-mounted control device according to any one of claims 1 to 3, wherein: When the current value exceeds the threshold, the control unit determines whether a time integral value of the current value since exceeding the threshold exceeds a corresponding value corresponding to the elapsed time, and switches the cutoff unit to the cutoff state when it is determined that the current value exceeds the corresponding value.

5. The vehicle-mounted control device according to any one of claims 1 to 3, wherein: When the current value exceeds the threshold value, the control unit determines whether a time integral value of the square of the current value since exceeding the threshold value exceeds a corresponding value corresponding to the elapsed time, and switches the cutoff unit to the cutoff state if it is determined that the corresponding value is exceeded.

6. The vehicle-mounted control device according to any one of claims 1 to 3, wherein: The cut-off upper limit value is preset, the cut-off upper limit value is greater than the threshold value and less than the maximum current that can be passed, the maximum current that can be passed is the maximum current that the relay can maintain in the on state, When the current value exceeds the cutoff upper limit value, the control unit switches the cutoff unit to the cutoff state regardless of the elapsed time.

7. The vehicle-mounted control device according to claim 6, wherein: The maximum current that can be passed is smaller than a saturation current that flows through the power line when a ground fault occurs in the power line, The cutoff upper limit value is set so that the cutoff unit switches to the cutoff state before the current value reaches the saturation current in consideration of a time lag from when it is determined that the current value exceeds the cutoff upper limit value until the cutoff unit switches to the cutoff state.

8. The vehicle-mounted control device according to claim 6, wherein: The cutoff upper limit value is set so that the cutoff portion switches to the cutoff state before the current value reaches the maximum passable current, taking into account a time lag from when it is determined that the current value exceeds the cutoff upper limit value until the cutoff portion switches to the cutoff state.

9. The vehicle-mounted control device according to any one of claims 1 to 3, wherein: The relay is controlled by a second control unit different from the control unit, When the control unit determines that the second control unit controls the relay to be in the off state in a state where the current value exceeds the threshold value, the control unit switches the cutoff unit to the cutoff state regardless of the elapsed time.

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