Cutting control device

Abstract

The cutting control device (30) controls the cutting unit (34). An in-vehicle system (10) is provided with: an electricity storage unit (91); a power line (31) that is a path for transmitting power between the power storage unit (91) and the load (94); and a cut-off unit (34) that switches, in the power line (31), from a permitted state in which power supply from the power storage unit (91) side to the load (94) side is permitted to a cut-off state in which power supply is cut off. A cutoff control device (30) is provided with a current detection unit (38), a voltage detection unit (39), and a control unit (20). The current detection unit (38) detects the current state of the current flowing through the power line (31). The voltage detection unit (39) detects the voltage state of the voltage in the power line (31). When the current state detected by the current detection unit (38) is a predetermined current increase state and the voltage state detected by the voltage detection unit (39) is a predetermined voltage decrease state, the control unit (20) instructs the cutoff unit (34) to switch to the cutoff state.

Description

Technical Field

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

[0002] Patent document 1 discloses the following technology: a current detection unit is used to detect the magnitude of the current flowing through the power line, and in a control unit, the control unit monitors the signal obtained from the current detection unit. When the control unit determines that the rate of change of the current flowing through the power line is greater than a predetermined value, the control unit outputs a cut-off signal to a relay unit and a cut-off unit provided in the power line, and switches the relay unit and the cut-off unit to a cut-off state.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: International Publication No. 2021 / 010007 Summary of the invention

[0006] Problems to be solved by the invention

[0007] The technology disclosed in Patent Document 1 uses only the signal obtained from the current detection unit to determine whether to output a cutoff signal. Therefore, when noise is generated in the power line, the technology in Patent Document 1 may misjudge the noise as a change in current and output a cutoff signal. It is desirable to prevent such misjudgement.

[0008] The present disclosure has been made based on the above-described circumstances, and an object of the present disclosure is to provide a cutoff control device capable of appropriately cutting off a power line.

[0009] Means for solving problems

[0010] The cut-off control device disclosed in the present invention is used in a vehicle-mounted system and controls the cut-off unit. The vehicle-mounted system has: a storage unit; a power line, which is a path for transmitting power between the storage unit and the load; and a cut-off unit, which switches in the power line from a permitted state that allows power supply from the storage unit side to the load side to a cut-off state that cuts off the power supply. The cut-off control device has: a current detection unit that detects the current state of the current flowing through the power line; a voltage detection unit that detects the voltage state of the voltage in the power line; and a control unit that instructs the cut-off unit to switch to the cut-off state when the current state detected by the current detection unit is a predetermined current rising state and the voltage state detected by the voltage detection unit is a predetermined voltage falling state.

[0011] Effects of the Invention

[0012] According to the present disclosure, it is possible to appropriately cut off the electric power path. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] [ Figure 1 ] Figure 1 This is a block diagram illustrating an in-vehicle system including the cutoff control device according to the first embodiment.

[0014] [ Figure 2 ] Figure 2 This is a graph showing the region where the current rising state and the voltage falling state are established.

[0015] [ Figure 3 ] Figure 3 This is a graph showing an example in which the current flowing through the power line rises sharply when the power line is grounded.

[0016] [ Figure 4 ] Figure 4 This is a flowchart illustrating the flow of processing in the control unit according to the first embodiment.

[0017] [ Figure 5 ] Figure 5 This is a block diagram illustrating an in-vehicle system including a cutoff control device according to another embodiment. DETAILED DESCRIPTION

[0018] [Description of Embodiments of the Present Disclosure]

[0019] First, embodiments of the present disclosure will be described below.

[0020] [1] The cut-off control device disclosed in the present invention is used in an on-vehicle system and controls a cut-off unit. The on-vehicle system includes: a power storage unit; a power line, which is a path for transmitting power between the power storage unit and the load; and a cut-off unit, which switches in the power line from a permitted state that allows power supply from the power storage unit side to the load side to a cut-off state that cuts off the power supply. The cut-off control device includes a current detection unit, a voltage detection unit, and a control unit. The current detection unit detects the current state of the current flowing through the power line. The voltage detection unit detects the voltage state of the voltage in the power line. When the current state detected by the current detection unit is a predetermined current rising state and the voltage state detected by the voltage detection unit is a predetermined voltage falling state, the control unit instructs the cut-off unit to switch to the cut-off state.

[0021] The above-mentioned cut-off control device [1] switches the cut-off portion to the cut-off state when both the current rising state and the voltage falling state are confirmed, so it is possible to more accurately grasp whether the short-circuit current has occurred and switch the cut-off portion to the cut-off state when the short-circuit current occurs. For example, in the example of judging the occurrence of the short-circuit current only by the current rising state and the example of judging the occurrence of the short-circuit current only by the voltage falling state, there is a concern about erroneous cut-off caused by noise, etc., but the cut-off control device can make such erroneous cut-off less likely to occur.

[0022] [2] In the cutoff control device of [1] above, the current detection unit can detect a first detection value capable of determining the current value of the power line as a current rising state, and the voltage detection unit can detect a second detection value capable of determining the voltage value of the power line as a voltage falling state. The current rising state may be a state in which the current value of the power line is above a current threshold value, and the voltage falling state may be a state in which the voltage value of the power line is below a voltage threshold value.

[0023] The above-mentioned cut-off control device [2] can take into account both protection against short-circuit current and suppression of erroneous cut-off by having a simple structure that determines whether the current value of the power line is above the current threshold and whether the voltage value of the power line is below the voltage threshold based on a first detection value that can determine the current value and a second detection value that can determine the voltage value.

[0024] [3] The vehicle-mounted system may be configured to include a switch, which is provided in the power line and switches the power line between an energized state and a non-energized state. When a current exceeding a specified value flows through the switch in the energized state, the energized state is released and switched to a non-energized state by generating an electromagnetic repulsive force. The current detection unit of the cut-off control device of [1] above may detect a first detection value capable of determining the current value of the power line as a current rising state, and the current rising state is a state in which the current value of the power line is above a current threshold value, and the current threshold value is a value smaller than a specified value.

[0025] The cutoff control device of the above-mentioned [3] can set the current threshold value within a range where switching to the non-energized state due to electromagnetic repulsion does not occur.

[0026] [4] In the cutoff control device of [1] or [3] above, the voltage drop state may be a state in which a drop rate of the voltage of the power line is greater than or equal to a certain value.

[0027] The above-mentioned cutoff control device [4] can switch the cutoff unit to the cutoff state when the voltage drop rate is equal to or higher than a certain value in the current rising state, thereby achieving both rapid protection against short-circuit current and suppression of erroneous cutoff.

[0028] [5] The vehicle-mounted system may include a measuring unit for measuring the internal resistance value of the power storage unit. In the above-mentioned cut-off control devices [1] to [3], the voltage drop state is a state in which the voltage value of the power line is below the voltage threshold value, and the control unit can set the voltage threshold value based on the internal resistance value measured by the measuring unit in such a way that the voltage threshold value is reduced as the internal resistance value increases.

[0029] The cutoff control device of [5] above can set the voltage threshold in accordance with the actual internal resistance value, based on the actual measurement of the internal resistance value of the power storage unit, so that the voltage threshold value is reduced as the actual internal resistance value increases.

[0030] [6] In the cut-off control device of [2] or [3] above, the voltage drop state is a state in which the voltage value of the power line is below the voltage threshold. The voltage threshold can be determined based on the multiplication value and the output voltage of the power storage unit, according to an operation formula in which the voltage threshold is increased as the output voltage is larger and the voltage threshold is decreased as the multiplication value is larger. The multiplication value is a value obtained by multiplying the current threshold by the sum of the internal resistance value of the power storage unit and the resistance value of the power line.

[0031] The shutdown control device of the above-mentioned [6] can appropriately set the voltage threshold value by reflecting the internal resistance value, the resistance value of the power line, the current threshold value, and the output voltage of the power storage unit.

[0032] [7] The vehicle-mounted system may include a switch disposed in the power line and switching the power line between an energized state and a non-energized state. In the cutoff control device of any one of [1] to [3] above, the voltage detection unit may detect a voltage state on the load side relative to the switch.

[0033] The cutoff control device of the above-mentioned [7] can suppress the dark current caused by the power storage unit from flowing to the voltage detection unit when the switch is in the non-energized state, thereby saving power.

[0034] [8] The vehicle-mounted system may include a switch provided in the power line to switch the power line between an energized state and a non-energized state. In the cutoff control device of any one of [1] to [3] above, the voltage detection unit is capable of detecting a voltage state on the side of the power storage unit relative to the switch.

[0035] The cutoff control device of [8] above can easily detect the voltage state at a position closer to the power storage unit, and can therefore detect the voltage state of the power storage unit in a manner that minimizes voltage drops occurring in the power line.

[0036] [9] The cutoff portion of the cutoff control device according to any one of [1] to [8] above may use any one of a pyrotechnic fuse, an electromagnetic fuse or a semiconductor switch.

[0037] The shutoff control device of the above-mentioned [9] can easily switch to the shutoff state in a short time.

[0038] [Details of the embodiments of the present disclosure]

[0039] <Implementation Method 1>

[0040] The vehicle-mounted system 10 having the cutoff control device 30 of the first embodiment is configured as a vehicle-mounted power supply system, and includes a power storage unit 91, a power line 31, a cutoff unit 34, a relay 36 as a switch, a measuring unit 37, and a cutoff control device 30. The cutoff control device 30 includes a current detection unit 38, a voltage detection unit 39, and a control unit 20. The cutoff control device 30 is used in the vehicle-mounted system 10, and has a function of controlling the cutoff unit 34. The vehicle-mounted system 10 is configured to be able to apply a voltage from the power storage unit 91 to the load 94 via the power line 31, which is a path for transmitting power between the power storage unit 91 and the load 94.

[0041] [Overview of the in-vehicle system]

[0042] The power storage unit 91 is a DC power source that generates a DC voltage, and a power supply unit such as a lead battery, a LiB, an AC generator, or a converter is used. A high potential terminal and a low potential terminal are provided in the power storage unit 91. The power storage unit 91 is configured to apply a predetermined output voltage to the power line 31.

[0043] The power line 31 includes a high potential side power line 31A and a low potential side power line 31B. The high potential side terminal of the power storage unit 91 is electrically connected to the high potential side power line 31A. The low potential side terminal of the power storage unit 91 is electrically connected to the low potential side power line 31B. The power storage unit 91 generates a predetermined potential difference (i.e., the output voltage of the power storage unit 91) between the high potential side power line 31A and the low potential side power line 31B. The power line 31 is a path for transmitting power between the power storage unit 91 and the load 94.

[0044] The high potential side power line 31A is electrically connected to the positive electrode of the load 94 . The low potential side power line 31B is electrically connected to the negative electrode of the load 94 .

[0045] The load 94 is an electronic component for vehicle use, and is applied to products such as electric components, ECUs, and ADAS target components. The load 94 is electrically connected to the power line 31 .

[0046] In the present disclosure, "electrical connection" is preferably a structure in which the potentials of both connection objects are equal and the connection is in a state of mutual conduction (a state in which current flows). However, it is not limited to this structure. For example, "electrical connection" may also be configured such that an electrical component is interposed between two connection objects and the two connection objects are connected in a state in which conduction is possible.

[0047] The cut-off unit 34 uses, for example, a pyrotechnic fuse (PYROFUSE (registered trademark)) or the like. The cut-off unit 34 is interposed in the low-potential side power line 31B. The cut-off unit 34 is switched from a permitted state in which power is permitted to be supplied from the power storage unit 91 side to the load 94 side in the power line 31 to a cut-off state in which power is cut off by receiving a drive signal D from the control unit 20 described later, thereby stopping the supply of power from the power storage unit 91 side to the load 94 side.

[0048] When the pyrotechnic fuse is provided with a driving signal D, for example, the built-in gunpowder is ignited, and the explosive force of the gunpowder is used to instantly separate the conductive line of the power line 31 on the side of the electric storage unit 91 and the power line 31 on the side of the load 94, thereby putting it into a cut-off state. Therefore, compared with a relay, the pyrotechnic fuse can put the power line 31 into a cut-off state in a short time. The cut-off unit 34 switched to the cut-off state will not switch from the cut-off state to the allowed state.

[0049] The relay 36 includes a high potential side relay 36A and a low potential side relay 36B. The high potential side relay 36A and the low potential side relay 36B use, for example, a contactor, a mechanical relay, etc. The high potential side relay 36A is provided in the high potential side power line 31A. The low potential side relay 36B is sandwiched in the low potential side power line 31B on the load 94 side compared to the cut-off unit 34. The high potential side relay 36A and the low potential side relay 36B are switched to a non-energized state by receiving a cut-off signal C3 from the control unit 20. The high potential side relay 36A and the low potential side relay 36B are switched to an energized state by receiving a conduction signal C4 from the control unit 20. That is, the relay 36 is provided in the power line 31, and switches the high potential side power line 31A and the low potential side power line 31B to an energized state and a non-energized state, respectively.

[0050] The measuring unit 37 is a battery monitoring device for vehicle use, and can function as a battery management system (BMS) that monitors and manages the power storage unit 91. In addition, the measuring unit 37 can also function as a battery sensing unit (BSU) that measures the voltage, current, temperature, etc. related to the power storage unit 91. The measuring unit 37 is configured to calculate the internal resistance value R0 of the power storage unit 91 based on the measured voltage, current, temperature, etc. related to the power storage unit 91, and output the internal resistance value R0. For example, the internal resistance value R0 gradually increases as the power storage unit 91 is discharged. In addition, the internal resistance value R0 of the power storage unit 91 gradually decreases as it is charged.

[0051] The current detection unit 38 is interposed in the low potential side power line 31B on the side of the power storage unit 91 relative to the cut-off unit 34. The current detection unit 38 includes, for example, a resistor and a differential amplifier, and is configured to output a value indicating a current flowing through the low potential side power line 31B (specifically, an analog voltage corresponding to the value of the current flowing through the low potential side power line 31B) as a first detection value A. That is, the current detection unit 38 detects the current state of the current flowing through the power line 31 as the first detection value A.

[0052] The voltage detection unit 39 is configured as a part of the control unit 20 described later, for example. The voltage detection unit 39 is configured to obtain a second detection value V corresponding to the potential difference between the high potential side power line 31A and the low potential side power line 31B (that is, the voltage value of the power line 31). That is, the voltage detection unit 39 detects the voltage state of the voltage in the power line 31 as the second detection value V. The voltage detection unit 39 detects the voltage state on the side of the storage unit 91 relative to the relay 36. For example, the voltage detection unit 39 is configured to calculate and compute the second detection value V at predetermined short intervals. Moreover, the control unit 20 is configured to be able to store the second detection value V calculated and computed by the voltage detection unit 39 last time as the second detection value V0 in the storage area 20A provided in the control unit. The second detection values ​​V and V0 correspond to the output voltage of the storage unit 91.

[0053] The control unit 20 controls the switching of the cut-off unit 34 to the cut-off state. The control unit 20 is composed of, for example, a circuit and components that can be controlled, such as a microcomputer and an FPGA. The control unit 20 is configured to be able to input the internal resistance value R0 of the storage unit 91 from the measuring unit 37. In addition, the control unit 20 is configured to be able to input the first detection value A from the current detection unit 38. The control unit 20 can perform a determination control to determine whether to switch the cut-off unit 34 to the cut-off state based on the first detection value A, the internal resistance value R0, the second detection value V, and V0. The first detection value A is obtained from the current detection unit 38. The internal resistance value R0 is input from the measuring unit 37. The second detection value V is a value obtained by the voltage detection unit 39. The second detection value V0 is a value stored in the storage area 20A.

[0054] [About judgment control]

[0055] The determination control in the control unit 20 is described. For example, when a ground fault occurs at any point of the power line 31, the current flowing in the power line 31 increases sharply over time, and at the same time, the first detection value A also increases sharply over time. Moreover, when the first detection value A becomes greater than the current threshold value Ath of a magnitude greater than the first threshold value Th1 and less than the second threshold value Th2, the control unit 20 determines that it is in a current rising state. Moreover, when the second detection value V becomes less than the voltage threshold value Vth, the control unit 20 determines that it is in a voltage falling state. When the control unit 20 determines that it is in a voltage rising state and a voltage falling state, it outputs a drive signal D to the cut-off unit 34.

[0056] [Regarding the first threshold, the second threshold, and the current threshold]

[0057] The first threshold value Th1 corresponds to the maximum current value that can flow through the power line 31 when the power line 31 is in a normal state. Here, the normal state refers to, for example, a voltage value in the power line 31 that is a predetermined value greater than 0V (that is, a state where the power line 31 is not grounded). The maximum current value that can flow through the power line 31 is, for example, the current that flows through the power line 31 when the load 94 such as the motor in the vehicle is operated to the maximum extent.

[0058] The second threshold value Th2 as a specified value corresponds to the maximum current value at which the relay 36 can maintain the cut-off state. The second threshold value Th2 is a value greater than the first threshold value Th1. When the current flowing through the power line 31 flows into the relay 36, an electromagnetic repulsive force is generated in the relay 36 to change the relay 36 from the energized state to the non-energized state. The electromagnetic repulsive force increases according to the magnitude of the current flowing into the relay 36. If the current flowing into the relay 36 is greater than the second threshold value Th2, the electromagnetic repulsive force is greater than the force that keeps the relay 36 in the energized state, the relay 36 changes to the non-energized state and an arc is generated in the relay 36, and the relay 36 may fail. In this way, the relay 36 is configured so that when a current of a specified value (the maximum current value (the second threshold value Th2) at which the relay 36 can maintain the cut-off state) or more flows through itself in the energized state, the energized state is released by the generation of electromagnetic repulsive force and switched to the non-energized state.

[0059] The current threshold value Ath is a value used to determine whether the current state of the current flowing through the power line 31 detected by the current detection unit 38 is a predetermined current rising state. The current threshold value Ath is set to a range greater than the first threshold value Th1 and smaller than the second threshold value Th2. The control unit 20 determines that it is a current rising state (that is, the condition for switching the cut-off unit 34 to the cut-off state is satisfied) when the first detection value A input from the current detection unit 38 exceeds the current threshold value Ath. That is, the current rising state is a state in which the first detection value A of the power line 31 is greater than the current threshold value Ath. The current detection unit 38 detects the first detection value A that can determine the current value of the power line 31 as the current rising state.

[0060] [About voltage threshold]

[0061] The voltage threshold value Vth is a value for determining whether the voltage state of the voltage in the power line 31 detected by the voltage detection unit 39 is a predetermined voltage drop state. The control unit 20 determines the voltage threshold value Vth based on the following equation 1.

[0062] Vth=V0-Ath×(R0+Rj)…(Formula 1)

[0063] Here, V0 is the second detection value V0 obtained by the voltage detection unit 39 last time and stored in the storage area 20A, Ath is the current threshold Ath, R0 is the internal resistance value R0 of the storage unit 91 input from the measurement unit 37, and Rj is the resistance value Rj in the power line 31. Figure 1 As shown, the resistance value Rj is the resistance value in the high potential side power line 31A from the position where the terminal on the high potential side of the power storage unit 91 is connected to the position where the signal line S of the voltage detection unit 39 is connected to the high potential side power line 31A. The voltage threshold Vth may be adjusted by adding a correction value to Formula 1 or by weighting each value.

[0064] The voltage threshold Vth is determined according to the calculation formula shown in Formula 1 based on the value obtained by multiplying the added value obtained by adding the internal resistance value R0 of the power storage unit 91 and the resistance value Rj of the power line 31 by the current threshold value Ath, that is, the multiplied value (Ath×(R0+Rj)) and the second detection value V0 (the output voltage of the power storage unit 91). As shown in Formula 1, the larger the second detection value V0 is, the larger the voltage threshold Vth is, and the larger the multiplied value (Ath×(R0+Rj)) is, the smaller the voltage threshold Vth is. The control unit 20 sets the voltage threshold Vth based on the internal resistance value R0 measured by the measuring unit 37 so that the voltage threshold Vth is smaller as the internal resistance value R0 is larger.

[0065] The control unit 20 compares the second detection value V calculated by the voltage detection unit 39 with the voltage threshold value Vth, and determines that the voltage is in a reduced state when the second detection value V is less than the voltage threshold value Vth. That is, the voltage reduced state is a state in which the second detection value V of the power line 31 is less than the voltage threshold value Vth. In this way, the voltage detection unit 39 detects the second detection value V that can determine the voltage value of the power line 31 as a reduced state.

[0066] When it is determined that the current state detected by the current detector 38 is a predetermined current increase state and the voltage state detected by the voltage detector 39 is a predetermined voltage decrease state, the control unit 20 outputs the drive signal D to the cutoff unit 34 to instruct the cutoff unit 34 to switch to the cutoff state.

[0067] Specifically, if Figure 2 As shown, in the case of the region C where the first detection value A is greater than the current threshold value Ath and the second detection value V is less than the voltage threshold value Vth, the control unit 20 outputs the drive signal D to the cut-off unit 34. The current threshold value Ath is set to a range greater than the first threshold value Th1 and smaller than the second threshold value Th2. The current threshold value Ath is set to a value smaller than the second threshold value Th2, so that the cut-off unit 34 can be switched to the cut-off state before the electromagnetic repulsive force becomes greater than the force that keeps the relay 36 in the energized state (that is, before the relay 36 fails).

[0068] [Time until the cutting unit switches to the cutting state]

[0069] Next, the time until the cutoff unit 34 switches to the cutoff state when a ground fault occurs at any point of the power line 31 and the second detection value V becomes less than the voltage threshold value Vth (voltage drop state) is described. Figure 3 As shown in FIG. 1 , when a ground fault occurs at any point of the power line 31 at time T0, the current value of the current flowing through the power line 31 rises sharply, and the first detection value A reaches the current threshold value Ath at time T1. At this time, both the current rising state and the voltage falling state are established. Therefore, the control unit 20 outputs the drive signal D to the cut-off unit 34 at time T1. The cut-off unit 34 starts the operation of switching from the allowed state to the cut-off state when the drive signal D is input. After time T1, the first detection value A (the current value of the current flowing through the power line 31) continues to rise.

[0070] Then, at time T2, the switching action of the cut-off unit 34 to the cut-off state is completed. The time Tb from time T1 to time T2 can be changed according to the specifications of the control unit 20 and the cut-off unit 34. If the current threshold Ath is set to be close to the second threshold Th2, the times T1 and T2 become later timings, and if the current threshold Ath is set to be close to the first threshold Th1, the times T1 and T2 become earlier timings.

[0071] The time T4 can be defined by, for example, a maximum time Tm, which is the maximum time for which a current having a magnitude greater than the second threshold value Th2 is allowed to flow through the relay 36, starting from the time T3 when the first detection value A reaches the second threshold value Th2. For example, when the current continues to flow through the relay 36 for a time longer than the maximum time Tm, the possibility of a failure of the relay 36 increases. Therefore, the time T2 when the switching action of the cut-off portion 34 to the cut-off state is completed is preferably set to a timing earlier than the time T4. Specifically, by setting the current threshold value Ath to be closer to the first threshold value Th1 than the second threshold value Th2, the timing of the time T2 can be advanced, and the time between the time T2 and the time T4 can be longer.

[0072] [About the operation of the control unit]

[0073] Next, refer to Figure 4 An example of the operation of the control unit 20 will be described below. Figure 4 The flowchart shown is a process that is repeatedly executed by the control unit 20 when a predetermined start condition is satisfied.

[0074] First, in step S1 , a start switch (ignition switch) provided in the vehicle is switched from an OFF state to an ON state. Then, the control unit 20 supplies an ON signal C4 to the relay 36 , thereby switching the relay 36 from a non-energized state to an energized state.

[0075] When the control unit 20 moves to step S2, it determines whether the current flowing through the power line 31 is in the current rising state and the voltage in the power line 31 is in the voltage falling state. Specifically, the control unit 20 determines whether the first detection value A (the current value flowing through the power line 31) from the current detection unit 38 is greater than the current threshold value Ath. At the same time, the control unit 20 determines whether the second detection value V (the voltage value in the power line 31) obtained by the voltage detection unit 39 is less than the voltage threshold value Vth. In step S2, when the first detection value A is less than the current threshold value Ath or the second detection value V is greater than the voltage threshold value Vth (no in step S2), the control unit 20 determines that the current is not in the rising state and the voltage is falling. Then, the control unit 20 repeatedly executes step S2. In step S2, when the first detection value A is greater than the current threshold value Ath and the second detection value V is less than the voltage threshold value Vth (yes in step S2), the control unit 20 determines that the current is in the rising state and the voltage is falling. Then, the process proceeds to step S3, where the control unit 20 outputs a drive signal D to the cut-off unit 34, and the process ends. Figure 4 Execution of the processing in .

[0076] Next, the effects of this structure are exemplified.

[0077] The cut-off control device 30 is used in the vehicle-mounted system 10, and controls the cut-off unit 34. The vehicle-mounted system 10 includes a power storage unit 91, a power line 31, and a cut-off unit 34. The power line 31 is a path for transmitting power between the power storage unit 91 and the load 94. The cut-off unit 34 switches from a permitted state in which power is allowed to be supplied from the power storage unit 91 side to the load 94 side in the power line 31 to a cut-off state in which power is cut off. The cut-off control device 30 includes a current detection unit 38, a voltage detection unit 39, and a control unit 20. The current detection unit 38 detects the current state of the current flowing in the power line 31. The voltage detection unit 39 detects the voltage state of the voltage in the power line 31. When the current state detected by the current detection unit 38 is a predetermined current rising state and the voltage state detected by the voltage detection unit 39 is a predetermined voltage falling state, the control unit 20 instructs the cut-off unit 34 to switch to the cut-off state.

[0078] According to this configuration, since the cut-off portion 34 is switched to the cut-off state when both the current rising state and the voltage falling state are confirmed, it is possible to more accurately grasp whether a short-circuit current has been generated, and switch the cut-off portion 34 to the cut-off state when a short-circuit current has been generated. For example, in an example where the generation of a short-circuit current is determined only by a current rise or an example where the generation of a short-circuit current is determined only by a voltage drop, there is a concern of erroneous cut-off caused by noise or the like, but the cut-off control device 30 can make such erroneous cut-off less likely to occur.

[0079] In the cut-off control device 30, the current detection unit 38 detects the first detection value A that can determine the current value of the power line 31 as the current rising state, and the voltage detection unit 39 detects the second detection value V that can determine the voltage value of the power line 31 as the voltage falling state. The current rising state is a state in which the current value of the power line 31 is greater than the current threshold value Ath, and the voltage falling state is a state in which the voltage value of the power line 31 is less than the voltage threshold value Vth.

[0080] According to this structure, by using a simple structure in which whether the current value of the power line 31 is above the current threshold value Ath and whether the voltage value of the power line 31 is below the voltage threshold value Vth is determined based on the first detection value A that can determine the current value and the second detection value V that can determine the voltage value, it is possible to take into account both protection against short-circuit current and suppression of erroneous disconnection.

[0081] The vehicle-mounted system 10 has a relay 36 that is provided in the power line 31 and switches the power line 31 between an energized state and a non-energized state. The relay 36 is configured to release the energized state and switch to a non-energized state by generating an electromagnetic repulsive force when a current exceeding a second threshold value Th2 flows in the energized state. The current detection unit 38 of the cut-off control device 30 detects a first detection value A that can determine the current value of the power line 31 as a current rising state, and the current rising state is a state in which the current value of the power line 31 is above a current threshold value Ath, and the current threshold value Ath is a value smaller than the second threshold value Th2. According to this structure, the current threshold value Ath can be set within a range in which switching to a non-energized state based on electromagnetic repulsion does not occur.

[0082] The vehicle-mounted system 10 includes a measuring unit 37 for measuring the internal resistance value R0 of the power storage unit 91. In the cutoff control device 30, the voltage drop state is a state in which the voltage value of the power line 31 is less than the voltage threshold value Vth, and the control unit 20 sets the voltage threshold value Vth in a manner that the voltage threshold value Vth is reduced as the internal resistance value R0 is larger, based on the internal resistance value R0 measured by the measuring unit 37. According to this configuration, based on the premise of actually measuring the internal resistance value R0 of the power storage unit 91, the voltage threshold value Vth can be set in accordance with the actual internal resistance value R0 in a manner that the voltage threshold value Vth is reduced as the actual internal resistance value R0 is larger.

[0083] In the cut-off control device 30, the voltage drop state is a state in which the voltage value of the power line 31 is below the voltage threshold value Vth. The voltage threshold value Vth is determined based on the multiplied value and the second detection value V0 (the output voltage of the storage unit 91), according to the calculation formula that the larger the second detection value V0 is, the greater the voltage threshold value Vth is, and the larger the multiplied value is, the greater the voltage threshold value Vth is. The multiplied value is a value obtained by multiplying the added value obtained by adding the internal resistance value R0 of the storage unit 91 and the resistance value Rj of the power line 31 by the current threshold value Ath. According to this structure, the voltage threshold value Vth can be appropriately set by reflecting the internal resistance value R0, the resistance value Rj of the power line 31, the current threshold value Ath, and the output voltage of the storage unit 91.

[0084] The vehicle-mounted system 10 includes a relay 36, which is provided in the power line 31 and switches the power line 31 between an energized state and a non-energized state. In the cutoff control device 30, the voltage detection unit 39 detects the voltage state on the side of the power storage unit 91 relative to the relay 36. According to this structure, it is easy to detect the voltage state at a position closer to the power storage unit 91, so the voltage state of the power storage unit 91 can be detected in a form that eliminates the voltage drop generated in the power line 31 as much as possible.

[0085] A pyrotechnic fuse is used as the cutoff section 34 of the cutoff control device 30. According to this structure, it is easy to switch to the cutoff state in a short time.

[0086] <Other Implementation Methods>

[0087] The embodiments disclosed herein are to be considered in all respects as illustrative and non-restrictive. The scope of the present invention is not limited to the embodiments disclosed herein, but is indicated by the claims, and is intended to include all modifications within the meaning and scope equivalent to the claims.

[0088] Different from implementation mode 1, Figure 5 As shown, the voltage detection unit 39 may also be configured to detect the voltage state on the load 94 side relative to the relay 36. According to this configuration, when the relay 36 is in a non-energized state, it is possible to suppress the dark current based on the power storage unit 91 from flowing to the voltage detection unit 39, thereby saving power. In this case, the resistance value Rj of the power line 31 is greater than the resistance value of the first embodiment.

[0089] It is also possible to configure, unlike the first embodiment, that when the rate of decrease of the voltage of the power line is above a certain value, it is determined to be a voltage drop state. For example, the amount of change K of the voltage in the power line per unit time is calculated by the following formula 2. K=(V-V0) / ΔT ... (Formula 2), here, V is the second detection value V obtained by the voltage detection unit this time, V0 is the second detection value V0 obtained by the voltage detection unit last time, and ΔT is the period ΔT of the time during which the voltage detection unit repeatedly calculates the second detection value. When the voltage of the power line decreases over time, V is a value smaller than V0. Therefore, the amount of change K is a value less than 0 (i.e., a negative value). In addition, the greater the degree of decrease in the voltage of the power line, the smaller the amount of change K becomes in a manner that is further away from 0. For example, a voltage threshold value less than 0 may be stored in the control unit, and when the amount of change K is less than the voltage threshold value (the rate of decrease of the voltage of the power line is above a certain value), it is determined to be a voltage drop state. According to this configuration, the cutoff portion can be switched to the cutoff state when the rate of voltage drop is equal to or higher than a certain value in the current rising state, thereby achieving both rapid protection against short-circuit current and suppression of erroneous cutoff.

[0090] Unlike the first embodiment, it is also possible to configure such that when the rate of increase of the current in the power line is above a certain value, it is determined that the current is in an increasing state. For example, the amount of change Ki of the current in the power line per unit time is calculated by the following formula 3. Ki=(A-A0) / ΔT ... (Formula 3), here, A is the first detection value A detected by the current detection unit this time, A0 is the first detection value A0 detected by the current detection unit last time, and ΔT is the period ΔT of the time when the current detection unit repeatedly detects the first detection value. The first detection value A0 is configured to be stored in the storage area 20A, for example. When the current of the power line increases over time, A is a value greater than A0. Therefore, the amount of change Ki is a value greater than 0 (i.e., a positive value). In addition, the greater the degree of increase of the current in the power line, the greater the value of the amount of change Ki becomes in a manner that is further away from 0. For example, a current threshold greater than 0 may be stored in the control unit, and when the amount of change Ki is greater than the current threshold (the rate of increase of the current in the power line is above a certain value), it is determined that the current is in an increasing state.

[0091] A comparator may be used as the current detection unit. In this case, a predetermined high-level signal is output when the current value in the power line represents a value above a predetermined threshold value, and a predetermined low-level signal is output when the current value represents a value below the predetermined threshold value. Alternatively, a structure using a current transformer or the like may be used.

[0092] Unlike the first embodiment, a cut-off unit may be provided on the high potential side power line. Also, a current detection unit may be provided on the high potential side power line. Also, a voltage detection unit may be provided as a separate structure from the control unit.

[0093] Unlike the first embodiment, a semiconductor switch such as an electromagnetic fuse or MOSFET may be used in the cutoff portion. Even if these components are used, switching to the cutoff state can be performed in a short time.

[0094] Description of Reference Numerals

[0095] 10…In-vehicle systems

[0096] 20…Control Department

[0097] 20A…Storage area

[0098] 30... Cut off control device

[0099] 31…Power lines

[0100] 31A…High potential side power line

[0101] 31B…Low potential side power line

[0102] 34…Cutting section

[0103] 36…Relay (Switch)

[0104] 36A...High potential side relay

[0105] 36B…Low potential side relay

[0106] 37…Measurement Department

[0107] 38…Current detection unit

[0108] 39…Voltage detection unit

[0109] 91…Electricity storage unit

[0110] 94…Load

[0111] A, A0...first detection value

[0112] Ath…Current threshold

[0113] C…Region

[0114] C3…cut off signal

[0115] C4…conduction signal

[0116] D…Drive signal

[0117] K, Ki…Change

[0118] R0…Internal resistance value

[0119] Rj…resistance value of power line

[0120] S…Signal line

[0121] T0, T1, T2, T3, T4...time

[0122] Tb…time

[0123] Th1…First threshold

[0124] Th2…Second threshold value (specified value)

[0125] Tm…Maximum time

[0126] V, V0...second detection value

[0127] Vth…voltage threshold

[0128] ΔT…period

Claims

1. A cutoff control device, used in an on-vehicle system, and controlling a cutoff unit, the on-vehicle system comprising: a power storage unit; a power line which is a path for transmitting power between the power storage unit and a load; and a cutoff unit which switches from a permitted state in the power line in which power supply from the power storage unit side to the load side is permitted to a cutoff state in which the power supply is cut off, The cut-off control device comprises: a current detection unit for detecting a current state of a current flowing through the power line; a voltage detection unit configured to detect a voltage state of a voltage in the power line; and The control unit instructs the cutoff unit to switch to the cutoff state when the current state detected by the current detection unit is a predetermined current increase state and the voltage state detected by the voltage detection unit is a predetermined voltage decrease state.

2. The cut-off control device according to claim 1, wherein: The current detection unit detects a first detection value capable of specifying a current value of the power line as the current increase state, The voltage detection unit detects a second detection value capable of specifying a voltage value of the power line as the voltage drop state, The current rising state is a state in which the current value of the power line is greater than a current threshold value. The voltage drop state is a state in which the voltage value of the power line is equal to or lower than a voltage threshold.

3. The cut-off control device according to claim 1, wherein: The vehicle-mounted system includes a switch, which is provided in the power line and switches the power line between an energized state and a non-energized state. The switch is configured to release the energized state and switch to the non-energized state by generating an electromagnetic repulsive force when a current exceeding a predetermined value flows in the energized state. The current detection unit detects a first detection value capable of specifying a current value of the power line as the current increase state, The current rising state is a state in which the current value of the power line is greater than a current threshold value. The current threshold is a value smaller than the predetermined value.

4. The cut-off control device according to claim 1 or 3, wherein: The voltage drop state is a state in which a drop rate of the voltage of the power line is equal to or higher than a certain value.

5. The cut-off control device according to any one of claims 1 to 3, wherein: The vehicle-mounted system includes a measuring unit configured to measure an internal resistance value of the power storage unit. The voltage drop state is a state in which the voltage value of the power line is below a voltage threshold. The control unit sets the voltage threshold value based on the internal resistance value measured by the measurement unit so as to reduce the voltage threshold value as the internal resistance value increases.

6. The cut-off control device according to claim 2 or 3, wherein: The voltage drop state is a state in which the voltage value of the power line is below a voltage threshold. The voltage threshold is determined based on the multiplication value and the output voltage of the storage unit, according to an operation formula in which the voltage threshold increases as the output voltage increases and the voltage threshold decreases as the multiplication value increases. The multiplication value is a value obtained by multiplying the current threshold by a sum obtained by adding the internal resistance value of the storage unit and the resistance value of the power line.

7. The cut-off control device according to any one of claims 1 to 3, wherein: The vehicle-mounted system includes a switch, which is provided in the power line and switches the power line between an energized state and a non-energized state. The voltage detection unit detects the voltage state on the load side relative to the switch.

8. The cut-off control device according to any one of claims 1 to 3, wherein: The vehicle-mounted system includes a switch, which is provided in the power line and switches the power line between an energized state and a non-energized state. The voltage detection unit detects the voltage state on the power storage unit side relative to the switch.

9. The cut-off control device according to any one of claims 1 to 3, wherein: The cutoff portion uses any one of a pyrotechnic fuse, an electromagnetic fuse, or a semiconductor switch.

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