Cutting control device

Abstract

A cutoff control device (1) is used in an in-vehicle system (100). An in-vehicle system (100) is provided with a power supply unit (90), a power line (80), a shutter (11), and a cutoff unit (12). The power line (80) is a path for transmitting power between the power supply unit (90) and the load (91). The switch (11) is provided in the power line (80) and switches the power line (80) between a power-on state and a power-off state. The cut-off unit (12) switches from a permitted state in which power supply from the power supply unit (90) side to the load (91) side is permitted in the power line (80) to a cut-off state in which the power supply is cut off. The cutoff control device (1) is provided with a control unit (14) that switches the cutoff unit (12) to the cutoff state when the value of the current flowing through the power line (80) exceeds a first threshold value (Ith1). The first threshold value (Ith1) is smaller than a second threshold value (Ith2), which is the maximum current value at which the switch (11) can maintain the power line (80) in the energized state.

Description

Technical Field

[0001] The present disclosure relates to a cut-off control device. Background Art

[0002] Patent Document 1 discloses a load circuit for supplying electric power to a load. The load circuit includes a battery and a switch (semiconductor switch) provided between the battery and the load, and the switch switches on and off to switch driving and stopping of the load.

[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] The above switch may not operate normally when a current exceeding a threshold value flows through it. If a structure capable of withstanding a larger current is desired, the size of the switch tends to become larger.

[0006] An object of the present disclosure is to provide a technology capable of suppressing an increase in the size of a switch and suppressing a situation in which the switch cannot operate normally.

[0007] Means for solving problems

[0008] The cut-off control device of the present disclosure is used in an in-vehicle system, which includes: a power supply unit; a power line, which is a path for transmitting power between the power supply unit and the load; a switch, which is arranged on the power line, and switches the power line between a power-on state and a non-power-on state; and a cut-off unit, which switches from a permitted state in the power line that allows power supply from the power supply unit side to the load side to a cut-off state that cuts off the power supply, wherein the cut-off control device includes a control unit, which switches the cut-off unit to the cut-off state when the current value flowing through the power line exceeds a first threshold value, the first threshold value is smaller than a second threshold value, and the second threshold value is the maximum current value at which the switch can maintain the power line in the power-on state.

[0009] Effects of the Invention

[0010] The technology disclosed in the present invention can suppress an increase in the size of a switch and suppress a situation in which the switch cannot operate normally. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 1 is a diagram schematically illustrating a configuration of an in-vehicle system including the cutoff control device according to the first embodiment. Figure 2This is a graph of correspondence data showing the correspondence between the elapsed time from a ground fault and the current value flowing through the power line. DETAILED DESCRIPTION

[0012] Hereinafter, embodiments of the present disclosure are listed and illustrated.

[0013] [1] A cut-off control device for use in an in-vehicle system, the in-vehicle system comprising: a power supply unit; a power line that is a path for transmitting power between the power supply unit and a load; a switch that is provided on the power line and switches the power line between an energized state and a non-energized state; and a cut-off unit that switches from a permitted state in the power line that permits power supply from the power supply unit side to the load side to a cut-off state that cuts off the power supply, wherein the cut-off control device comprises a control unit that switches the cut-off unit to the cut-off state when a current value flowing through the power line exceeds a first threshold value, the first threshold value being smaller than a second threshold value, the second threshold value being the maximum current value at which the switch can maintain the power line in the energized state.

[0014] In the above-mentioned cut-off control device, when the current value flowing through the power line exceeds the first threshold value, the control unit switches the cut-off unit to the cut-off state. In addition, the first threshold value is set to a value smaller than the second threshold value, and the second threshold value is the maximum current value at which the switch can maintain the power line in the energized state. Therefore, before the switch cannot maintain the power line in the energized state, the control unit easily switches the cut-off unit to the cut-off state. Therefore, even if the size of the switch is suppressed and the second threshold value becomes smaller, the current exceeding the second threshold value is difficult to flow through the switch, and as a result, it is easy to avoid the situation where the switch cannot maintain the power line in the energized state. Therefore, according to this structure, the size of the switch can be suppressed, and the situation where the switch cannot operate normally can be suppressed.

[0015] [2] According to the cut-off control device described in [1], the switch is an electromagnetic relay, which sets the power line to the energized state when the switch itself is in the on state, and sets the power line to the non-energized state when the switch itself is in the off state. When a current greater than the second threshold value flows through the switch itself, the electromagnetic repulsion releases the on state and switches to the off state.

[0016] According to this configuration, the control unit can easily switch the cutoff unit to the cutoff state before the switch in the on state is switched to the off state by the electromagnetic repulsive force.

[0017] [3] The cutoff control device according to [1] or [2], wherein the second threshold value is smaller than a saturation current flowing through the power line when a ground fault occurs in the power line.

[0018] According to this configuration, in order to suppress the size increase of the switch, a switch whose maximum current value that can maintain the energized state is smaller than the saturation current can be used in the vehicle-mounted system. In addition, in such a configuration, it is possible to suppress the switch from malfunctioning.

[0019] [4] According to the cut-off control device described in [3], the first threshold value is set to switch the cut-off unit to the cut-off state before the current value flowing through the power line reaches the saturation current, taking into account the time lag from when it is determined that the current value flowing through the power line exceeds the first threshold value to when the cut-off unit is switched to the cut-off state.

[0020] According to this configuration, the cutoff unit can be switched to the cutoff state before the value of the current flowing through the power line reaches the saturation current.

[0021] [5] According to the cut-off control device described in any one of [1] to [4], the first threshold value is set to switch the cut-off unit to the cut-off state before the current value flowing through the power line reaches the second threshold value, taking into account the time lag from the determination that the current value flowing through the power line exceeds the first threshold value to the switching of the cut-off unit to the cut-off state.

[0022] According to this configuration, the cutoff unit can be switched to the cutoff state before the current value flowing through the power line reaches the second threshold value. Therefore, it is possible to avoid a situation where a current exceeding the second threshold value flows through the switch and the switch cannot maintain the power line in the energized state.

[0023] [6] The cutoff control device according to any one of [1] to [5], wherein the first threshold is greater than a third threshold, and the third threshold is a maximum current value that can flow through the power line in a normal state of the power line.

[0024] According to this configuration, it is easy to avoid the cutoff portion being switched to the cutoff state in a normal state of the power line.

[0025] [7] According to any one of [1] to [6], the cutoff unit uses any one of a pyrotechnic fuse, a semiconductor switch and an electromagnetic fuse.

[0026] According to this configuration, the cutoff portion can be easily and quickly switched to the cutoff state.

[0027] <First Embodiment>

[0028] Figure 1 The vehicle-mounted system 100 shown is a system mounted on a vehicle and includes a power supply unit 90 , a load 91 , a power line 80 , a cutoff control device 1 , and a second control unit 92 .

[0029] The power supply unit 90 is, for example, a DC power supply that generates a DC voltage, such as a battery. The battery is, for example, a lead acid battery, a lithium ion 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 a path for transmitting power between the power supply unit 90 and 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.

[0030] The cut-off control device 1 is used in a vehicle-mounted system 100. The cut-off control device 1 is configured as, for example, a junction box. The cut-off control device 1 includes a housing 10, a switch 11, a cut-off unit 12, a current detection unit 13, and a control unit 14. The switch 11, the cut-off unit 12, the current detection unit 13, and the control unit 14 are arranged in the housing 10. The housing 10 includes a first terminal unit 10A and a second terminal unit 10B.

[0031] The power line 80 includes a first wiring portion 81, a second wiring portion 82, and a conductive line 83. The first wiring portion 81 and the second wiring portion 82 are disposed outside the housing 10, and the conductive line 83 is disposed inside the housing 10.

[0032] The first wiring section 81 is configured as, for example, an electric wire. One end of the first wiring section 81 is electrically connected to the power supply section 90, and the other end is electrically connected to the first terminal section 10A. The second wiring section 82 is configured as, for example, an electric wire. One end of the second wiring section 82 is electrically connected to the second terminal section 10B, and the other end is electrically connected to the load 91.

[0033] The conductive line 83 is configured as a bus bar, for example. One end of the conductive line 83 is electrically connected to the first terminal portion 10A, and the other end is electrically connected to the second terminal portion 10B. The conductive line 83 includes a first conductive line 84, a second conductive line 85, and a third conductive line 86. One end of the first conductive line 84 is electrically connected to the first terminal portion 10A, and the other end is electrically connected to one end of the cut-off portion 12. One end of the second conductive line 85 is electrically connected to the other end of the cut-off portion 12, and the other end is electrically connected to one end of the switch 11. One end of the third conductive line 86 is electrically connected to the other end of the switch 11, and the other end is electrically connected to the second terminal portion 10B.

[0034] The switch 11 is configured as an electromagnetic relay, for example, and has contacts that are operated by electromagnetic force. The switch 11 is provided on the power line 80 (more specifically, the conductive line 83) to switch the power line 80 between a conducting state and a non-conducting state. The switch 11 is provided between the second conductive line 85 and the third conductive line 86 to switch between a conducting state and a non-conducting state. When the second conductive line 85 and the third conductive line 86 are in a conducting state, the power line 80 is in a conducting state. When the second conductive line 85 and the third conductive line 86 are in a non-conducting state, the power line 80 is in a non-conducting state. When the switch 11 is in the on state, the second conductive line 85 and the third conductive line 86 are in a conducting state, and the power line 80 is in a conducting state. When the switch 11 is in the off state, the second conductive line 85 and the third conductive line 86 are in a non-conducting state, and the power line 80 is in a non-conducting state. The switch 11 is controlled by the second control unit 92 .

[0035] The cut-off portion 12 is configured, for example, as a pyrofuse (registered trademark), a semiconductor switch, an electromagnetic fuse, or the like. The cut-off portion 12 is provided in the power line 80 (more specifically, the conductive line 83). The cut-off portion 12 is arranged on the power line 80 (more specifically, the conductive line 83) at the power source 90 side relative to the switch 11. The cut-off portion 12 switches from a permitted state in which power supply from the power source 90 side to the load 91 side is permitted in the power line 80 to a cut-off state in which the power supply is cut off. The cut-off portion 12 is provided between the first conductive line 84 and the second conductive line 85. The cut-off portion 12 switches from a permitted state in which power supply from the first conductive line 84 side to the second conductive line 85 side is permitted to a cut-off state in which the power supply is cut off. When the cut-off portion 12 is a pyrofuse (registered trademark), a semiconductor switch, or an electromagnetic fuse, it is easy and quick to switch to the cut-off state. The cut-off unit 12 may be configured to be able to return to the enabling state after being in the cut-off state, or may be configured to be unable to return. The cut-off unit 12 is controlled by the control unit 14 .

[0036] The current detection unit 13 is configured as a known current sensor, for example. The current detection unit 13 detects the current flowing through the power line 80 (more specifically, the second conductive line 85). 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 92, respectively.

[0037] The control unit 14 controls the cut-off 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 92. The control unit 14 determines the current value flowing through the power line 80 based on the signal output from the current detection unit 13. The control unit 14 switches the cut-off unit 12 to the cut-off state when the current value flowing through the power line 80 exceeds the first threshold value Ith1.

[0038] The second control unit 92 controls the switch 11. The second control unit 92 is configured as an MCU (Micro Controller Unit), for example. The second control unit 92 is arranged outside the housing 10. When a predetermined start condition is satisfied, the second control unit 92 controls the switch 11 to switch the power line 80 to a power-on state. Specifically, the second control unit 92 switches the switch 11 to a closed state. The start condition is, for example, that the start switch of the vehicle is switched to a closed state. When a predetermined stop condition is satisfied, the second control unit 92 controls the switch 11 to switch the power line 80 to a non-power-on state. Specifically, the second control unit 92 switches the switch 11 to a disconnected state. The stop condition is, for example, that the start switch of the vehicle is switched to a disconnected state. When a predetermined disconnection condition is satisfied, the second control unit 92 controls the switch 11 to switch the power line 80 to a non-power-on state. Specifically, the second control unit 92 switches the switch 11 to a disconnected state. The disconnection condition is, for example, a condition that can be satisfied based on the current value flowing through the power line 80. The condition that can be satisfied based on the current value flowing through the power line 80 is, for example, a condition that the current value flowing through the power line 80 exceeds a reference value. The second control unit 92 determines the current value flowing through the power line 80 based on the signal output from the current detection unit 13 .

[0039] Depending on the performance, the switch 11 may not be able to maintain the energized state due to the increase in the current value flowing through the power line 80 before the disconnection condition is satisfied and the second control unit 92 switches it to the disconnected state. Therefore, the first threshold value Ith1 is set to a value smaller than the second threshold value Ith2, which is the maximum current value at which the switch 11 can maintain the power line 80 in the energized state. Therefore, before the switch 11 cannot maintain the power line 80 in the energized state, the control unit 14 easily switches the disconnection unit 12 to the disconnection state. Therefore, even if the second threshold value is reduced to suppress the size of the switch 11, it is difficult for the current exceeding the second threshold value Ith2 to flow through the switch 11, and as a result, it is easy to avoid the situation where the switch 11 cannot maintain the power line 80 in the energized state. Therefore, according to this structure, it is possible to suppress the size of the switch 11 and suppress the situation where the switch 11 cannot operate normally.

[0040] In addition, the switch 11 is an electromagnetic relay. When the current flowing through the power line 80 flows into the electromagnetic relay, an electromagnetic repulsive force is generated in the electromagnetic relay to change the electromagnetic relay from the off state to the on 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 becomes larger than the above-mentioned second threshold value Ith2, the electromagnetic repulsive force becomes larger 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, an arc is generated in the electromagnetic relay, and the electromagnetic relay may fail. However, as described above, the above-mentioned first threshold value Ith1 is set to a value smaller than the second threshold value Ith2. Therefore, before the switch 11 in the on state is switched to the off state by the electromagnetic repulsive force, the control unit 14 easily switches the cut-off unit 12 to the cut-off state.

[0041] The second threshold value Ith2 is set to a value smaller than the saturation current IS flowing 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 second terminal portion 10B when the power supply unit 90 is fully charged and the vehicle-mounted system 100 is not degraded.

[0042] According to this configuration, in order to suppress the size increase of the switch 11, the switch 11 whose maximum current value that can maintain the energized state is smaller than the saturation current IS can be used in the vehicle-mounted system 100. In addition, in such a configuration, it is possible to suppress the switch 11 from failing to operate normally.

[0043] The first threshold value Ith1 is set so that the cut-off unit 12 is switched to the cut-off state before the current value flowing through the power line 80 reaches the saturation current IS, taking into account the time lag TL from when it is determined that the current value flowing through the power line 80 exceeds the first threshold value Ith1 to when the cut-off unit 12 is switched to the cut-off state. The first threshold value Ith1 is based on, for example, the time lag TL and the correspondence data indicating the correspondence relationship between the elapsed time from the occurrence of the ground fault and the current value flowing through the power line 80 (see Figure 2 ) to set.

[0044] The time lag TL is generated based on the time from when the control unit 14 determines that the first threshold value Ith1 is exceeded to when the control of switching the cut-off unit 12 to the cut-off state is started, and the time from when the control of switching the cut-off unit 12 to the cut-off state is started to when the cut-off unit 12 is switched to the cut-off state. The time lag TL is obtained, for example, based on test results or simulation results.

[0045] The corresponding data is obtained based on, for example, test results or simulation results. The test results or simulation results are, for example, the results of causing a ground fault in the second terminal portion 10B when the vehicle-mounted system 100 is not degraded and the power supply unit 90 is fully charged.

[0046] exist Figure 2 In the corresponding data 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 power line 80 reaches the saturation current IS.

[0047] The time when the current value flowing through the power line 80 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).

[0048] Time constant τ = (L1+L2+L3) / (R1+R2+R3)…Formula (1)

[0049] 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 second terminal unit 10B. 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 second terminal unit 10B. R3 is the resistance value of the ground fault location. In addition, L3 and R3 can be changed according to the mode of the ground fault, and therefore, for example, can also be set to 0.

[0050] For example, the current value corresponding to time T1 which does not reach time T4 even if time lag TL is taken into account is set as the first threshold value Ith1. That is, time T1 at which time T2 after time lag TL becomes earlier than time T4 is determined, and the current value corresponding to this time T1 is set as the first threshold value Ith1.

[0051] According to this configuration, the cutoff portion 12 can be switched to the cutoff state before the current value flowing through the power line 80 reaches the saturation current IS.

[0052] The first threshold value Ith1 is set so that the cut-off unit 12 is switched to the cut-off state before the current value flowing through the power line 80 reaches the second threshold value Ith2, taking into account the time lag TL from when it is determined that the current value flowing through the power line 80 exceeds the first threshold value Ith1 to when the cut-off unit 12 is switched to the cut-off state. The first threshold value Ith1 is set, for example, based on the time lag TL and the above-mentioned corresponding data.

[0053] exist Figure 2In the corresponding data shown, the time when the current value flowing through the power line 80 reaches the second threshold value Ith2 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 first threshold value Ith1. 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 first threshold value Ith1.

[0054] According to this configuration, the cutoff unit 12 can be switched to the cutoff state before the current value flowing through the power line 80 reaches the second threshold value Ith2. Therefore, it is possible to avoid a situation where a current exceeding the second threshold value Ith2 flows through the switch 11 and the switch 11 cannot maintain the power line 80 in the energized state.

[0055] The first threshold value Ith1 is set to a value greater than the third threshold value Ith3, which is the maximum current value 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 the threshold voltage. The threshold voltage is a value greater than 0V. The maximum current value 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 the motor in the vehicle is operated to the maximum extent when the power supply unit 90 is fully charged.

[0056] According to this configuration, it is easy to avoid a situation where the cutoff portion 12 is switched to the cutoff state when the power line 80 is in the normal state.

[0057] <Other Implementation Methods>

[0058] The present disclosure is not limited to the embodiments described above and illustrated in the drawings. For example, the features of the embodiments described above or later can be combined in their entirety within the scope of non-contradiction. In addition, any feature in the embodiments described above or later can be omitted if it is not explicitly stated as a required feature. Furthermore, the embodiments described above can also be changed as follows.

[0059] In the above embodiment, the second control unit 92 is disposed outside the cutoff control device 1, but may be disposed inside the cutoff control device 1. That is, the second control unit 92 may be a part of the cutoff control device 1.

[0060] 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, but is intended to include all modifications within the scope disclosed in the claims or within the scope equivalent to the claims.

[0061] Description of symbols 1: Cut off the control device 10: Shell 10A: First terminal 10B: Second terminal part 11: Opener and closer 12: Cutting part 13: Current detection unit 14: Control Department 80: Power lines 81: First wiring section 82: Second wiring section 83: Conductive circuit 84: First conductive circuit 85: Second conductive circuit 86: The third conductive line 90: Power supply department 91: Load 92: Second Control Unit 100: In-vehicle systems IS: Saturation current Ith1: first threshold Ith2: Second threshold Ith3: The third threshold.

Claims

1. A cut-off control device, used in an in-vehicle system, the in-vehicle system comprising: a power supply unit; a power line, which is a path for transmitting power between the power supply unit and a load; a switch, which is provided in the power line, and switches the power line between an energized state and a non-energized state; and a cut-off unit, which switches from a permitted state in the power line, which permits power supply from the power supply unit side to the load side, to a cut-off state in which the power supply is cut off, wherein: The cutoff control device includes a control unit configured to switch the cutoff unit to the cutoff state when a current value flowing through the power line exceeds a first threshold value. The first threshold is smaller than a second threshold, and the second threshold is a maximum current value at which the switch can maintain the power line in the energized state.

2. The cut-off control device according to claim 1, wherein: The switch is an electromagnetic relay, which sets the power line to the energized state when the switch is in the on state, and sets the power line to the non-energized state when the switch is in the off state. When a current greater than the second threshold value flows through the switch, the switch releases the on state by electromagnetic repulsion and switches to the off state.

3. The cut-off control device according to claim 1 or 2, wherein: The second threshold value is smaller than a saturation current flowing through the power line when a ground fault occurs in the power line.

4. The cut-off control device according to claim 3, wherein: The first threshold is set so that the cutoff unit is switched to the cutoff state before the current value flowing through the power line reaches the saturation current, taking into account a time lag from when it is determined that the current value flowing through the power line exceeds the first threshold to when the cutoff unit is switched to the cutoff state.

5. The cut-off control device according to claim 4, wherein: The first threshold is set so that the cutoff unit is switched to the cutoff state before the current value flowing through the power line reaches the second threshold, taking into account a time lag from when it is determined that the current value flowing through the power line exceeds the first threshold to when the cutoff unit is switched to the cutoff state.

6. The cut-off control device according to claim 5, wherein: The first threshold is greater than a third threshold, and the third threshold is a maximum current value that can flow through the power line in a normal state of the power line.

7. The cut-off control device according to claim 6, wherein: The cutoff portion uses any one of a pyrotechnic fuse, a semiconductor switch, and an electromagnetic fuse.

8. The cut-off control device according to claim 1 or 2, wherein: The first threshold is set so that the cutoff unit is switched to the cutoff state before the current value flowing through the power line reaches the second threshold, taking into account a time lag from when it is determined that the current value flowing through the power line exceeds the first threshold to when the cutoff unit is switched to the cutoff state.

9. The cut-off control device according to claim 1 or 2, wherein: The first threshold is greater than a third threshold, and the third threshold is a maximum current value that can flow through the power line in a normal state of the power line.

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