Fuse detection device, fuse detection method, and computer program product

Abstract

Multiple fuses (F1, F2, ..., Fn) are configured in the current paths of multiple currents shunted from one end of the DC power supply (10). In the fuse detection device (11), one end of multiple capacitors (C1, C2, ..., Cn) is connected to one end of each of the multiple fuses (F1, F2, ..., Fn). Multiple currents flowing through the multiple capacitors (C1, C2, ..., Cn) are input to the circuit switch (30) and the circuit resistor (31). The microcomputer (37) instructs the circuit switch (30) to switch on or off, obtains the detection value of the resistor voltage, and detects whether there is a blown fuse among the fuses (F1, F2, ..., Fn) based on the obtained detection value.

Description

Technical Field

[0001] This disclosure relates to a fuse detection device, a fuse detection method, and a computer program.

[0002] This application claims priority based on Japanese Application No. 2020-157027, filed on September 18, 2020, and invokes all the contents of that Japanese application. Background Technology

[0003] Patent Document 1 discloses a power supply system for a vehicle that supplies power from a DC power source to a load. In this power supply system, a fuse is arranged in the current path of the current flowing from the positive terminal of the DC power source to the load. The load is an electrical device mounted on the vehicle.

[0004] Prior art literature

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2003-212065 Summary of the Invention

[0007] One aspect of the present disclosure discloses a fuse detection device for detecting whether a blown fuse exists among a plurality of fuses, the plurality of fuses being respectively disposed in a plurality of current paths shunt from one end of a DC power supply. The fuse detection device includes: a plurality of capacitors connected to one downstream end of each of the plurality of fuses; a circuit switch and a circuit resistor, to which a plurality of currents flowing through the plurality of capacitors are input; and a processing unit that performs processing, the processing unit instructing the circuit switch to be switched on, the processing unit acquiring a detection value of the resistance voltage across the circuit resistor as time elapses when the circuit switch is on, and the processing unit detecting whether a blown fuse exists among the plurality of fuses based on the acquired detection value.

[0008] One aspect of the disclosed fuse detection method involves a computer using a circuit to detect whether a blown fuse exists among a plurality of fuses. The circuit includes: a plurality of capacitors connected to one downstream end of each of the plurality of fuses, the plurality of fuses being respectively configured in a plurality of current paths shunt from one end of a DC power supply; and a circuit switch and a circuit resistor, input to a plurality of currents flowing through the plurality of capacitors. The computer performs the following steps: instructing the circuit switch to switch on; obtaining a detection value of the resistance voltage across the circuit resistor as it decreases over time while the circuit switch is on; and based on the obtained detection value, detecting whether a blown fuse exists among the plurality of fuses.

[0009] One aspect of the present disclosure discloses a computer program that uses a circuit to detect whether a blown fuse exists among a plurality of fuses. The circuit includes: a plurality of capacitors connected to one downstream end of each of the plurality of fuses, the plurality of fuses being respectively configured in a plurality of current paths shunt from one end of a DC power supply; and a circuit switch and a circuit resistor, input to a plurality of currents flowing through the plurality of capacitors. The computer program is configured to cause a computer to perform the following steps: instructing the circuit switch to switch on; obtaining a detected value of the resistance voltage across the circuit resistor as it decreases over time while the circuit switch is on; and based on the obtained detected value, detecting whether a blown fuse exists among the plurality of fuses.

[0010] It should be noted that this disclosure can be implemented not only as a fuse detection device with a processing unit possessing such features, but also as a fuse detection method that sets the processing of the above-mentioned features as steps, or as a computer program for causing a computer to execute the above-mentioned steps. Furthermore, this disclosure can be implemented as a semiconductor integrated circuit that implements part or all of the fuse detection device, or as a power supply system that includes the fuse detection device. Attached Figure Description

[0011] Figure 1 This is a block diagram showing the main structural components of the power supply system in Implementation 1.

[0012] Figure 2 It is a block diagram showing the main structure of a DC power supply.

[0013] Figure 3 This is an explanatory diagram of a computer-based detection method.

[0014] Figure 4 It is a block diagram showing the main structure of a microcomputer.

[0015] Figure 5 This is a flowchart showing the sequence of circuit breaker detection and processing.

[0016] Figure 6 This is a flowchart showing the sequence of circuit breaker detection and processing.

[0017] Figure 7 This is a block diagram showing the main structure of the microcomputer in Embodiment 2.

[0018] Figure 8 This is an explanatory diagram of the time constant estimation model.

[0019] Figure 9 It is a flowchart representing the order of processing for determining the time constant.

[0020] Figure 10This is an explanatory diagram outlining the fuse detection method in Implementation Method 3.

[0021] Figure 11 It is a graph representing the contents of a resistance-voltmeter.

[0022] Figure 12 This is a flowchart showing the sequence of circuit breaker detection and processing.

[0023] Figure 13 This is a flowchart showing the sequence of circuit breaker detection and processing.

[0024] Figure 14 This is a block diagram showing the main structural components of the power supply system in Embodiment 4. Detailed Implementation

[0025] [The problem this disclosure aims to solve]

[0026] As a type of power supply system, there exists a power supply system that supplies power to multiple loads via a DC power source. In such a system, fuses are installed along the current paths of multiple currents shunt from the positive terminal of the DC power source. In power supply systems with a large number of loads, i.e., a large number of fuses, it is often difficult to determine which fuse corresponds to each load. Moreover, if a load is not operating, one reason for the load's failure is the blowing of the fuses along the current paths to that load.

[0027] When there are many fuses, and a load is not operating, for example, a vehicle dealer needs to check whether each fuse has blown individually. The dealer could use a detector, for example, to measure the voltage across the fuse terminals to confirm whether it has blown. However, this process of checking multiple fuses individually is time-consuming and inefficient.

[0028] Therefore, the objective is to provide a suitable fuse detection device, fuse detection method, and computer program for detecting whether a fuse has blown among a plurality of fuses.

[0029] [The Effects of This Disclosure]

[0030] According to this disclosure, it is appropriate to detect whether there is a blown fuse among a plurality of fuses.

[0031] [Description of embodiments of this disclosure]

[0032] First, embodiments of this disclosure will be described. At least some of the embodiments described below may be combined arbitrarily.

[0033] (1) One aspect of the present disclosure is a fuse detection device that detects whether a blown fuse exists among a plurality of fuses, the plurality of fuses being respectively disposed in a plurality of current paths shunt from one end of a DC power supply, wherein the device includes: a plurality of capacitors connected to one end of the downstream side of each of the plurality of fuses; a circuit switch and a circuit resistor, the plurality of currents flowing through the plurality of capacitors being input; and a processing unit that performs processing, the processing unit instructing the circuit switch to switch to be on, the processing unit obtaining a detection value of the resistance voltage between the two ends of the circuit resistor as time passes when the circuit switch is on, and the processing unit detecting whether a blown fuse exists among the plurality of fuses based on the obtained detection value.

[0034] (2) In one aspect of the fuse detection device disclosed herein, the processing unit acquires the detection value of the resistor voltage over time when the circuit switch is on, the processing unit determines the time constant of the resistor voltage based on the acquired multiple detection values, and the processing unit detects whether there is a blown fuse among the multiple fuses based on the determined time constant.

[0035] (3) In one embodiment of the fuse detection device disclosed herein, the processing unit determines whether the power supply voltage of the DC power supply has changed during the acquisition of the plurality of detection values.

[0036] (4) In one embodiment of the fuse detection device disclosed herein, the processing unit inputs multiple detection values ​​to a learned model, the learned model having learned the relationship between the multiple detection values ​​of the resistor voltage and the time constant of the resistor voltage, and the processing unit determines the time constant of the resistor voltage based on the output of the learned model.

[0037] (5) In one embodiment of the fuse detection device disclosed herein, the processing unit obtains the power supply voltage value of the DC power supply, the processing unit obtains the detection value of the resistor voltage at a time point after a predetermined time has elapsed since the circuit switch was switched on, and the processing unit detects whether there is a blown fuse among the plurality of fuses based on the obtained power supply voltage value and the detection value.

[0038] (6) In one embodiment of the fuse detection device disclosed herein, the processing unit determines whether the power supply voltage of the DC power supply has changed from the time the circuit switch is switched to the on state until the predetermined time has elapsed.

[0039] (7) One aspect of the fuse detection device disclosed herein includes: a diode with its anode connected to one end of the DC power supply; and a discharge switch and a discharge resistor through which current flows from the cathode of the diode, wherein when the discharge switch is turned on, the current flows from one end of the capacitor in the order of the fuse, the diode, the discharge resistor and the other end of the capacitor.

[0040] (8) One aspect of the fuse detection device disclosed herein includes: a plurality of diodes, with the anodes connected to one end of the downstream side of each of the plurality of fuses; and a discharge switch and a discharge resistor through which current flows from the cathodes of the plurality of diodes, wherein when the discharge switch is turned on, the current flows from one end of the capacitor in the order of the diodes, the discharge resistor and the other end of the capacitor.

[0041] (9) In one aspect of the fuse detection device disclosed herein, the processing unit determines whether all of the plurality of fuses have blown based on whether the obtained detection value indicates 0V.

[0042] (10) One aspect of the fuse detection method disclosed herein uses a computer to detect whether a blown fuse exists among a plurality of fuses via a circuit, the circuit comprising: a plurality of capacitors connected to one downstream end of each of the plurality of fuses, the plurality of fuses being respectively configured in a plurality of current paths shunt from one end of a DC power supply; and a circuit switch and a circuit resistor, input to a plurality of currents flowing through the plurality of capacitors, wherein the computer performs the following steps: instructing the circuit switch to switch on; obtaining a detection value of the resistance voltage across the circuit resistor as time passes when the circuit switch is on; and based on the obtained detection value, detecting whether a blown fuse exists among the plurality of fuses.

[0043] (11) One aspect of the present disclosure provides a computer program that uses a circuit to detect whether a blown fuse exists among a plurality of fuses, the circuit comprising: a plurality of capacitors connected to one downstream end of each of the plurality of fuses, the plurality of fuses being respectively configured in a plurality of current paths shunt from one end of a DC power supply; and a circuit switch and a circuit resistor, input to a plurality of currents flowing through the plurality of capacitors, wherein the computer program is configured to cause a computer to perform the following steps: instructing the circuit switch to switch on; obtaining a detection value of the resistance voltage across the circuit resistor as time elapses while the circuit switch is on; and based on the obtained detection value, detecting whether a blown fuse exists among the plurality of fuses.

[0044] In the aforementioned fuse detection device, fuse detection method, and computer program, when the circuit switch is switched on while multiple capacitors are not accumulating power, the resistor voltage decreases over time from the DC power supply voltage. The time constant of the resistor voltage is represented by the product of the sum of the electrostatic capacitances of one or more capacitors connected to the unblown fuses and the resistance of the circuit. Therefore, the more fuses that blow, the smaller the time constant. The smaller the time constant, the more rapidly the resistor voltage decreases. Therefore, based on the detected value of the resistor voltage, it is appropriate to detect whether a blown fuse exists among the multiple fuses.

[0045] In the fuse detection device described above, the time constant of the resistor voltage is determined based on multiple acquired detection values. If the determined time constant is lower than the time constant of the resistor voltage when all fuses have not blown, a blown fuse is detected.

[0046] In the aforementioned fuse detection device, if the DC power supply voltage changes during the acquisition of multiple detection values, i.e., during the period of acquiring multiple detection values, an appropriate detection value cannot be obtained. Therefore, it is necessary to determine whether the power supply voltage has changed during the acquisition of multiple detection values.

[0047] In the aforementioned fuse detection device, multiple detected values ​​are input into a learned model. The learned model then outputs information representing the probability of a time constant corresponding to the resistor voltage, for example, with respect to multiple pre-set time constants. The time constant of the resistor voltage is determined based on the output of the learned model.

[0048] In the fuse detection device described above, the resistance voltage value at a predetermined time point elapsed since the circuit switch was switched on varies depending on the DC power supply voltage and the time constant. As mentioned earlier, when at least one fuse among multiple fuses has blown, the time constant of the resistance voltage decreases. Therefore, the resistance voltage value at the predetermined time point elapsed since the circuit switch was switched on is lower. If the detected value is lower than the resistance voltage value at the predetermined time point elapsed since the circuit switch was switched on when the number of blown fuses is zero, a blown fuse is detected.

[0049] In the aforementioned fuse detection device, if the DC power supply voltage changes from the time the circuit switch is switched to on until a predetermined time has elapsed, a suitable resistance voltage detection value cannot be obtained. Therefore, it is necessary to determine whether the DC power supply voltage has changed from the time the indicator circuit switch is switched to on until the predetermined time has elapsed.

[0050] In the aforementioned fuse detection device, the anode of a diode is connected to one end of a DC power supply. When the discharge switch is turned on, multiple capacitors discharge through a discharge resistor.

[0051] In the fuse detection device described above, the anodes of multiple diodes are connected to one downstream end of each of the multiple fuses. When the discharge switch is switched on, the multiple capacitors discharge through the discharge resistor.

[0052] In the aforementioned fuse detection device, even when the circuit switch is closed, no current flows through the circuit resistance if all fuses have blown. Therefore, at the moment the circuit switch is turned on, the resistor voltage is already 0V. The microcomputer detects that all fuses have blown when the resistor voltage is 0V.

[0053] [Details of the embodiments of this disclosure]

[0054] Hereinafter, specific examples of power supply systems according to embodiments of the present disclosure will be described with reference to the accompanying drawings. It should be noted that the present invention is not limited to these examples, but is disclosed in the claims and is intended to include all modifications within the meaning and scope equivalent to the claims.

[0055] (Implementation Method 1)

[0056] <Structure of Power Supply System>

[0057] Figure 1 This is a block diagram showing the main structural components of the power system 1 in Embodiment 1. The power system 1 is mounted in a vehicle. The power system 1 includes a DC power supply 10, a fuse detection device 11, and n fuses F1, F2, ... Fn, n power supply switches Q1, Q2, Qn and n loads U1, U2, Un. Here, n is an integer greater than or equal to 2.

[0058] Hereinafter, i represents any integer greater than 1 and less than n. Integer i can also be any integer greater than 1 and less than n.

[0059] One end of the DC power supply 10 is connected to one end of fuse Fi. The other end of fuse Fi is connected to one end of power supply switch Qi. The other end of power supply switch Qi is connected to one end of load Ui. The negative terminal of DC power supply 10 and the other end of load Ui are grounded. The connection point between fuse Fi and power supply switch Qi is connected to fuse detection device 11. Fuse detection device 11 is further grounded.

[0060] Load Ui is an electrical device installed in the vehicle. When the power supply switch Qi switches from open to closed, current flows from one end of the DC power supply 10 in the following order: fuse Fi, power supply switch Qi, load Ui, and the other end of the DC power supply 10, supplying power to load Ui. Load Ui operates when power is supplied by DC power supply 10. When the power supply switch Qi switches from closed to open, the flow of current through the power supply switch Qi stops, and the power supply from DC power supply 10 to load Ui stops. Load Ui stops operating when the power supply to it stops.

[0061] In n fuses F1, F2, ... With Fn not blown, and n power supply switches Q1, Q2, ... When Qn is connected, the n currents shunted from one end of the DC power supply 10 pass through n fuses F1, F2, and F3 respectively. Fn flows. Therefore, n fuses F1, F2, F3, F4, F5, F6, F7, F8, F9, F1, F1, F2, F1, F3, F4, F5, F6, F7, F8, F9, F1, F1, F1, F2 ... Fn. The fuse detection device 11 is connected to n fuses F1, F2, Fn respectively. One end of the downstream side of Fn.

[0062] Figure 2 This is a block diagram showing the main structure of the DC power supply 10. The DC power supply 10 includes a generator 20 and a battery 21. One end of the generator 20 is connected to the positive terminal of the battery 21 and one end upstream of the fuse Fi. The positive terminal of the battery 21 corresponds to one end of the aforementioned DC power supply 10. The other end of the generator 20 is connected to the negative terminal of the battery 21. The negative terminal of the battery 21 is grounded. Hereinafter, the voltage at the positive terminal of the battery 21 will be described as the power supply voltage. The reference potential of the power supply voltage is the ground potential.

[0063] An engine (not shown) is mounted on the vehicle. A generator 20, in conjunction with the engine, generates alternating current (AC) power and rectifies it into direct current (DC) power. When generating electricity, the generator 20 outputs a DC voltage associated with the rectified DC power as its output voltage. The output voltage of the generator 20 is higher than the output voltage of the battery 21. The reference potential for the output voltages of both the generator 20 and the battery 21 is ground.

[0064] Internal resistors (not shown) are installed inside both the generator 20 and the battery 21, through which the output voltage is transmitted. Therefore, the larger the current flowing through the internal resistors in both the generator 20 and the battery 21, the lower the output voltage. For example, the load U1 is assumed to be a starter for starting an engine. In this case, the load U1 operates when the generator 20 is not generating electricity. When the power supply switch Q1 is turned on, a large current is supplied from the battery 21 to the load U1. At this time, a large voltage drop occurs in the internal resistance of the battery 21, and the output voltage of the battery 21, i.e., the power supply voltage of the DC power supply 10, decreases.

[0065] As described above, the power supply voltage of DC power supply 10 varies depending on whether generator 20 is generating electricity and whether a high-current load is operating. The high-current load consists of n loads U1, U2, ... One of 、Un.

[0066] It should be noted that in n loads U1, U2, ... The series 1 and 2 may not include high-current loads. The following explains the situation with n loads U1, U2, and U3. Examples of high-current loads included in Un.

[0067] When generator 20 is generating electricity, the power supply voltage of DC power supply 10 is the output voltage of generator 20, and generator 20 charges battery 21. When generator 20 stops generating electricity, the power supply voltage of DC power supply 10 is the output voltage of battery 21. Assume that fuse Fi is not blown and power switch Qi is on. In this case, when generator 20 is generating electricity, generator 20 supplies power to load Ui. Similarly, in the case where generator 20 stops generating electricity, battery 21 supplies power to load Ui.

[0068] If the current flowing through fuse Fi exceeds the specified current value, fuse Fi will blow. When fuse Fi blows, the flow through fuse Fi stops. Fuse Fi prevents the continuous flow of overcurrent exceeding the specified current value for an extended period.

[0069] It should be noted that there are n fuses F1, F2, ... The specified current values ​​of Fn and Fn can also be the same. Moreover, the specified current value of fuse Fi can also be different from at least one of the specified current values ​​of other fuses.

[0070] With the vehicle's ignition switch on, to Figure 1 The fuse detection device 11 shown is input with an IG signal. When the IG signal is input, the fuse detection device 11 detects n fuses F1, F2, ... Does Fn contain any fuses that have blown, and what are the n fuses F1, F2, and Fn? Whether all fuses Fn have blown. The fuse detection device 11 determines the number of blown fuses if it detects that there are blown fuses.

[0071] <Structure of the fuse detection device 11>

[0072] like Figure 1 As shown, the fuse detection device 11 includes a circuit switch 30, a circuit resistor 31, a discharge switch 32, a discharge resistor 33, a voltage detection circuit 34, a first switching circuit 35, a second switching circuit 36, a microcomputer (hereinafter referred to as a microcomputer) 37, and n capacitors C1, C2, etc. Cn and n diodes D1, D2, The voltage detection circuit 34 has two voltage divider resistors, Rd1 and Rd2.

[0073] One end of capacitor Ci is connected to the downstream end of fuse Fi. There are n capacitors C1, C2, ... The other end of Cn is connected to one end of circuit switch 30. The other end of circuit switch 30 is connected to one end of circuit resistor 31. The other end of circuit resistor 31 is grounded. The anode of diode Di is also connected to one end of the downstream side of fuse Fi. n diodes D1, D2, ... The cathode of Dn is connected to one end of the discharge switch 32. The other end of the discharge switch 32 is connected to one end of the discharge resistor 33. The other end of the discharge resistor 33 is connected to the connection node between the capacitor Ci and the circuit switch 30.

[0074] One end of voltage divider resistor Rd1 is connected to the connection node between circuit switch 30 and circuit resistor 31. Within voltage detection circuit 34, the other end of voltage divider resistor Rd1 is connected to one end of voltage divider resistor Rd2. The other end of voltage divider resistor Rd2 is grounded. The connection node between the two voltage divider resistors Rd1 and Rd2 is connected to microcomputer 37. Microcomputer 37 is connected to both the first switching circuit 35 and the second switching circuit 36.

[0075] The microcomputer 37 outputs a first indication signal to the first switching circuit 35, representing a high-level voltage or a low-level voltage. The microcomputer 37 also outputs a second indication signal, representing a high-level voltage or a low-level voltage, to the second switching circuit 36. When the voltage indicated by the first indication signal switches from a low-level voltage to a high-level voltage, the first switching circuit 35 switches the circuit switch 30 to the ON position. When the voltage indicated by the first indication signal switches from a high-level voltage to a low-level voltage, the first switching circuit 35 switches the circuit switch 30 to the OFF position.

[0076] Similarly, when the voltage indicated by the second indicator signal switches from a low level to a high level, the second switching circuit 36 ​​switches the discharge switch 32 to the ON position. When the voltage indicated by the second indicator signal switches from a high level to a low level, the second switching circuit 36 ​​switches the discharge switch 32 to the OFF position.

[0077] An IG signal is input to the microcomputer 37. Before receiving the IG signal, the microcomputer 37 maintains the voltages represented by the first and second indicator signals at low and high levels, respectively. Therefore, the first switching circuit 35 keeps the circuit switch 30 open, and the second switching circuit 36 ​​keeps the discharge switch 32 closed.

[0078] When the discharge switch 32 is turned on, and when the capacitor Ci has accumulated power, the current flows from one end of the capacitor Ci in the order of diode Di, discharge switch 32, discharge resistor 33 and the other end of the capacitor Ci, and the capacitor Ci discharges.

[0079] Therefore, when the discharge switch 32 discharges to n capacitors C1, C2, ... When switching from a state where Cn has stored power to a state where it is switched on, the power is supplied from n diodes D1, D2, ... The cathode output current of diode Dn. From n diodes D1, D2, ... The current output from the cathode of Dn flows through the discharge switch 32 and the discharge resistor 33.

[0080] As previously described, with the voltages represented by the first and second indicator signals maintained at low and high levels respectively, the IG signal is input to the microcomputer 37. Upon receiving the IG signal, the microcomputer 37 switches the voltage represented by the second indicator signal from high to low. Consequently, the second switching circuit 36 ​​switches the discharge switch 32 to open. Next, the microcomputer 37 switches the first signal from low to high. Thus, the first switching circuit 35 switches the circuit switch 30 to open while the discharge switch 32 is open.

[0081] In this case, when fuse Fi has not blown, current flows from one end of DC power supply 10 in the order of fuse Fi, capacitor Ci, and circuit switch 30 until the voltage across capacitor Ci matches the power supply voltage of DC power supply 10. A portion of the current output from the downstream end of circuit switch 30 flows in the order of circuit resistor 31 and the other end of DC power supply 10. The remaining current output from the downstream end of circuit switch 30 flows in the order of voltage divider resistors Rd1 and Rd2 and the other end of DC power supply 10.

[0082] Here, the combined resistance of the voltage divider resistors Rd1 and Rd2 is much greater than the resistance of the circuit resistor 31. Therefore, the current flowing through the circuit resistor 31 is much greater than the current flowing through the voltage divider resistors Rd1 and Rd2. As a result, the current flowing through the circuit switch 30 is substantially the same as the current flowing through the circuit resistor 31.

[0083] In n fuses F1, F2, ... If Fn is not blown, when circuit switch 30 is switched to the on state, n currents flow through n capacitors C1, C2, ... Cn flows. As mentioned earlier, the current value flowing through circuit switch 30 is essentially the same as the current value flowing through circuit resistor 31, therefore n currents are input to circuit switch 30 and circuit resistor 31.

[0084] The voltage across resistor 31 in the circuit is referred to as the resistor voltage. Voltage detection circuit 34 detects the resistor voltage and outputs analog detection information representing the detected value to microcomputer 37. Within voltage detection circuit 34, voltage divider resistors Rd1 and Rd2 divide the resistor voltage. The voltage value obtained by dividing the resistor voltage through voltage divider resistors Rd1 and Rd2 is output to microcomputer 37 as analog detection information. Microcomputer 37 can calculate the detected value of the resistor voltage based on the voltage division ratio determined by the resistance values ​​of voltage divider resistors Rd1 and Rd2 and the detection information.

[0085] The microcomputer 37 repeatedly acquires the detection information output from the voltage detection circuit 34. When the number of acquired detection information reaches a predetermined number, the microcomputer 37 switches the voltage represented by the first indication signal to a high-level voltage. Consequently, the first switching circuit 35 switches the circuit switch 30 to open. Then, the microcomputer 37 switches the voltage represented by the second indication signal to a high-level voltage. Consequently, the second switching circuit 36 ​​switches the discharge switch 32 to close. As mentioned earlier, when the discharge switch 32 is closed, the n capacitors C1, C2, ... In Cn, the capacitor that stores electricity discharges through the discharge resistor 33.

[0086] The microcomputer 37 detects multiple detection values ​​represented by multiple detection information obtained from n fuses F1, F2, and F3. Does Fn contain any fuses that have blown, and n fuses F1, F2, etc.? Whether Fn is completely blown.

[0087] Figure 3This is a diagram illustrating the detection method performed by the microcomputer 37. Vb represents the power supply voltage of DC power supply 10. Vr represents the resistor voltage. The integer k represents the n fuses F1, F2, ... The number of fuses that tripped in Fn. The integer k is greater than or equal to 0 and less than (n-1). n capacitors C1, C2, ... The electrostatic capacitances of capacitors C1, C2, and Cn are the same. Let q represent the capacitances of the n capacitors. The electrostatic capacitances of C1 and Cn are respectively. r represents the resistance value of circuit resistor 31. t represents the time elapsed since circuit switch 30 switched to the on state.

[0088] It should be noted that the consistency of n electrostatic capacitors does not simply mean complete consistency. The state of consistency of n electrostatic capacitors also includes the state where the difference between the maximum and minimum values ​​of the n electrostatic capacitors converges within the error range.

[0089] Figure 3 The lower side shows the voltage shift across the circuit switch 30, i.e., the resistor voltage. The horizontal axis represents time t. Figure 3 As shown, when the circuit switch 30 is switched on, the resistor voltage decreases from the power supply voltage Vb over time. The resistor voltage Vr satisfies the following equation (1).

[0090] Vr=Vb exp(-t / τ) (1)

[0091] Here, τ is the time constant of the resistor voltage. " " indicates product.

[0092] like Figure 3 As shown in equation (1), the smaller the time constant τ, the faster the voltage across the resistor decreases. The time constant τ is represented by the following equation (2).

[0093] τ=(nk) q r (2)

[0094] (nk) q is a combination of n fuses F1, F2, ... The electrostatic capacitance of a parallel circuit of one or more capacitors connected to one or more unfrozen fuses in Fn. As mentioned earlier, the resistance value r is the resistance value of circuit resistance 31.

[0095] The microcomputer 37 determines the time constant τ of the resistor voltage based on multiple detected values. The determined time constant τ is (n q r), ((n-1) q r), ((n-2) q r) 、(q One of r). The time constant τ of the microcomputer 37 is less than (n) q In the case of r), it is determined that there are n fuses F1, F2, ... The fuse in Fn is the one that trips. The microcomputer 37 divides the determined time constant by (q). r). From this, the number of fuses that did not blow can be calculated, i.e., (nk). Microcomputer 37 Subtracts the value calculated by dividing the time constant from n, and thus calculates the number of fuses that blew, i.e., the integer k.

[0096] In n fuses F1, F2, ... If all fuses F1, F2, and Fn are blown, even if circuit switch 30 is closed, current will not flow through circuit resistor 31. Therefore, with n fuses F1, F2, and Fn blown, the current will not flow through circuit resistor 31. If all fuses F1, F2, and Fn blow, the resistor voltage is already 0V at the moment the circuit switch 30 turns on. Then, the resistor voltage remains at 0V. Therefore, when the detected value is 0V, the microcomputer 37 detects that all n fuses F1, F2, and Fn have blown. The circuit breaker of Fn.

[0097] <Structure of Microcomputer 37>

[0098] Figure 4 This is a block diagram showing the main structural components of the microcomputer 37. The microcomputer 37 includes a first output unit 41, a second output unit 42, an A / D converter 43, an input unit 44, a timer 45, a notification unit 46, a storage unit 47, and a control unit 48. These are all connected to an internal bus 49. The first output unit 41 is also connected to a first switching circuit 35. The second output unit 42 is also connected to a second switching circuit 36. The A / D converter 43 is also connected to the connection node between the voltage divider resistors Rd1 and Rd2 in the voltage detection circuit 34.

[0099] The first output unit 41 outputs a first indication signal to the first switching circuit 35. The control unit 48 instructs the first output unit 41 to switch the circuit switch 30 to "on". In this case, the first output unit 41 switches the voltage represented by the first indication signal to a high-level voltage. As a result, the first switching circuit 35 switches the circuit switch 30 to "on". The control unit 48 also instructs the first output unit 41 to switch the circuit switch 30 to "off". In this case, the first output unit 41 switches the voltage represented by the first indication signal to a low-level voltage. As a result, the first switching circuit 35 switches the circuit switch 30 to "off".

[0100] The second output unit 42 outputs a second indication signal to the second switching circuit 36. The control unit 48 instructs the second output unit 42 to switch the discharge switch 32 to the ON position. In this case, the second output unit 42 switches the voltage represented by the second indication signal to a high-level voltage. As a result, the second switching circuit 36 ​​switches the discharge switch 32 to the ON position. The control unit 48 also instructs the second output unit 42 to switch the discharge switch 32 to the OFF position. In this case, the second output unit 42 switches the voltage represented by the second indication signal to a low-level voltage. As a result, the second switching circuit 36 ​​switches the discharge switch 32 to the OFF position.

[0101] Analog detection information representing the detected value of the resistor voltage is input from the voltage detection circuit 34 to the A / D conversion unit 43. The A / D conversion unit 43 converts the analog detection information input from the voltage detection circuit 34 into digital detection information. The control unit 48 obtains the digital detection information from the A / D conversion unit 43. The detection value represented by the detection information obtained by the control unit 48 is consistent with the detected value of the resistor voltage detected by the voltage detection circuit 34 at the acquisition time.

[0102] It should be noted that consistency between two detected values ​​does not only mean complete consistency. Consistency also includes the state where the difference between the two detected values ​​converges within the error range.

[0103] Input the IG signal to the input unit 44.

[0104] The control unit 48 instructs the timer 45 to start the measurement. In this case, the timer 45 measures the elapsed time since the instruction to start the measurement. The measurement time measured by the timer 45 is read by the control unit 48. The control unit 48 then instructs the timer 45 to end the measurement. In this case, the timer 45 ends the measurement.

[0105] Notification unit 46 issues a notification as instructed by control unit 48. This notification is issued for n fuses F1, F2, ... If any of the fuses in Fn has blown, the notification unit 46 outputs a first notification signal, for example, indicating the number of blown fuses, to a device (not shown), thereby notifying the user. In the case of n fuses F1, F2, ... In the event that all Fn fuses are blown, the notification unit 46 may, for example, output a second notification signal representing the content to the device, thereby making a notification.

[0106] Storage unit 47 is non-volatile memory. Computer program P is stored in storage unit 47. Control unit 48 has a processing element that performs processing, such as a CPU (Central Processing Unit). The processing element (computer) of control unit 48 performs processes such as fuse detection by executing computer program P. Control unit 48 functions as a processing unit.

[0107] Fuse detection processing is performed if there are n fuses F1, F2, ... If any of the fuses in Fn is blown, then detect the n fuses F1, F2, ... Handling whether Fn completely blows.

[0108] It should be noted that the computer program P can also be stored on a storage medium A that can be read by the processing element of the control unit 48. In this case, the computer program P read from the storage medium A by a reading device (not shown) is written to the storage unit 47. The storage medium A is an optical disc, floppy disk, magnetic disk, magneto-optical disk, or semiconductor memory, etc. The optical disc is a CD (Compact Disc)-ROM (Read Only Memory), DVD (Digital Versatile Disc)-ROM, or BD (Blu-ray Disc), etc. The magnetic disk is, for example, a hard disk. Moreover, the computer program P can also be downloaded from a device (not shown) connected to a communication network (not shown), and the downloaded computer program P can be written to the storage unit 47.

[0109] The number of processing elements in the control unit 48 is not limited to one; it can be two or more. In this case, multiple processing elements can also collaboratively perform processes such as fuse detection according to the computer program P.

[0110] <Fuse Detection and Handling>

[0111] Figure 5 and Figure 6 This is a flowchart illustrating the sequence of fuse detection processing. The control unit 48 performs fuse detection processing when the circuit switch 30 and the discharge switch 32 are respectively in the open and closed states. The value of variable B is stored in the storage unit 47. The value of variable B indicates the number of times detection information representing the resistance voltage has been obtained. The value of variable B is changed by the control unit 48.

[0112] In the fuse detection process, the control unit 48 first determines whether an IG signal has been input to the input unit 44 (step S1). If the control unit 48 determines that no IG signal has been input (S1: No), it executes step S1 again and waits until an IG signal is input to the input unit 44. During the waiting period of the control unit 48, n capacitors C1, C2, ... Cn is discharged through discharge resistor 33.

[0113] When the control unit 48 determines that an IG signal has been input (S1: Yes), it sets the value of variable B to 0 (step S2) and instructs the second output unit 42 to switch the discharge switch 32 to open (step S3). As a result, the voltage indicated by the second indication signal switches to a low level voltage, and the second switching circuit 36 ​​switches the discharge switch 32 to open.

[0114] Next, the control unit 48 instructs the first output unit 41 to switch the circuit switch 30 to the ON position (step S4). As a result, the voltage indicated by the first indication signal switches to a high-level voltage, and the first switching circuit 35 switches the circuit switch 30 to the ON position. As previously described, when the circuit switch 30 is ON, the voltage across the circuit resistor 31, i.e., the resistor voltage, decreases from the power supply voltage of the DC power supply 10 over time.

[0115] Next, with the circuit switch 30 on, the control unit 48 obtains detection information representing the detected value of the resistor voltage from the A / D converter 43 (step S5). The detection value represented by the detection information obtained in step S5, which is executed immediately after step S4, is substantially the same as the power supply voltage value of the DC power supply 10. After executing step S5, the control unit 48 instructs the timer 45 to start measurement (step S6). Thus, the timer 45 measures the time elapsed since the instruction to start measurement.

[0116] Next, the control unit 48 increments the value of variable B by 1 (step S7) and determines whether the value of variable B matches a predetermined number (step S8). The predetermined number is an integer greater than or equal to 2. The predetermined number is a constant value and is preset. The predetermined number is stored, for example, in the storage unit 47. If the control unit 48 determines that the value of variable B does not match the predetermined number (S8: No), it determines whether the measurement time measured by the timer 45 is greater than or equal to a reference time (step S9). The reference time is a constant value and is preset. The reference time is stored, for example, in the storage unit 47.

[0117] If the control unit 48 determines that the measurement time is less than the reference time (S9: No), it executes step S9 again and waits until the measurement time reaches the reference time. If the control unit 48 determines that the measurement time is greater than or equal to the reference time (S9: Yes), it instructs the timer 45 to end the measurement (step S10). Thus, the timer 45 ends the measurement. After executing step S10, the control unit 48 executes step S5 again to obtain detection information.

[0118] As described above, before the value of variable B matches a predetermined number, the control unit 48 acquires detection information every elapsed time while the circuit switch 30 is on. The predetermined time is, for example, 5 ms. The predetermined number is preferably 3 or more.

[0119] When the control unit 48 determines that the value of variable B is consistent with the predetermined number (S8: Yes), it instructs the timer 45 to end the measurement (step S11). Thus, the timer 45 ends the measurement. Next, the control unit 48 instructs the first output unit 41 to switch the circuit switch 30 to open (step S12). As a result, the voltage indicated by the first indication signal switches to a low level, and the first switching circuit 35 switches the circuit switch 30 to open. The flow of current through the circuit resistor 31 stops.

[0120] Next, the control unit 48 instructs the second output unit 42 to switch the discharge switch 32 to the ON position (step S13). As a result, the voltage indicated by the second indication signal switches to a high-level voltage, and the second switching circuit 36 ​​switches the discharge switch 32 to the ON position. When the discharge switch 32 is switched to the ON position, as described above, the n capacitors C1, C2, ... Cn is discharged through discharge resistor 33.

[0121] After executing step S13, the control unit 48 determines all the fuses, i.e., the n fuses F1, F2, and F3, based on the multiple detection values ​​represented by the acquired detection information. Whether Fn is blown (step S14). In step S14, the control unit 48 determines whether all fuses are blown based on whether the detection value indicated by the acquired detection information is 0. In the first example of step S14, the control unit 48 determines that all fuses are blown when all multiple detection values ​​are 0V. In the second example of step S14, the control unit 48 determines that all fuses are blown when the detection value of the resistance voltage initially detected since the execution of step S4 is 0V.

[0122] If the control unit 48 determines that all fuses have not blown (S14: No), it determines whether the power supply voltage of the DC power supply 10 has changed during the acquisition of multiple detection information (step S15). If the power supply voltage of the DC power supply 10 has changed during the acquisition of multiple detection information, the control unit 48 cannot obtain appropriate detection information, i.e., appropriate detection value. Therefore, step S15 is executed. The period for acquiring multiple detection information is, for example, the period from the execution of step S4 to the execution of step S11.

[0123] When the power supply voltage rises, the difference between the two detected values ​​represented by two consecutively acquired detection information is small. Therefore, as a first method for detecting the rise in power supply voltage, a method can be listed as determining whether the difference between the two detected values ​​represented by two consecutively acquired detection information is less than a first threshold. The first threshold is a constant value and is preset. When the generator 20 generates electricity or a high-current load supplied with a large current stops operating, the power supply voltage rises. Therefore, as a second method for detecting the rise in power supply voltage, a method can be listed, for example, based on a status signal representing the operating state of the generator 20 or the high-current load, to determine whether the generator 20 or the high-current load is operating. As mentioned above, the high-current load is n loads U1, U2, ... One of 、Un.

[0124] When the power supply voltage drops, the difference between the two detected values ​​from two consecutively acquired detection information is large. Therefore, as a first method for detecting a drop in power supply voltage, a method can be listed as determining whether the difference between the two detected values ​​from two consecutively acquired detection information is greater than or equal to a second threshold. The second threshold is a constant value and is preset. The second threshold is greater than or equal to the first threshold. When the generator 20 stops generating electricity or a high-current load is operating, the power supply voltage drops. Therefore, as a second method for detecting a drop in power supply voltage, a method can be listed, for example, determining whether the generator 20 or the high-current load has stopped operating based on the aforementioned state signal.

[0125] If the control unit 48 determines that the power supply voltage has changed (S15: Yes), it executes step S2 and acquires multiple detection information again. If the control unit 48 determines that the power supply voltage has not changed (S15: No), it determines the time constant of the resistor voltage based on the multiple detection values ​​represented by the acquired multiple detection information (step S16). In the first example of step S16, the detection value represented by the detection information acquired in step S5, which is executed immediately after step S4, is taken as the power supply voltage, and the time constant is plotted as (n q r), ((n-1) q r), ((n-2) q r) 、(q (n-1) curves representing the change in resistor voltage. Among these (n-1) curves, one is selected that passes near multiple detection values ​​detected at reference time intervals. The control unit 48 determines the time constant of the selected curve.

[0126] In the second example of step S16, a series of equations are constructed by substituting multiple detection values ​​and multiple periods from the switching of the indicator circuit switch 30 to the acquisition of the detection information value into equation (1), respectively. The time constant τ is calculated by solving the constructed series of equations. Then, the time constant of the resistor voltage is determined to be (n q r), ((n-1) q r), ((n-2) q r) 、(q The value of r that is closest to the calculated time constant.

[0127] Next, based on the time constant determined in step S16, the control unit 48 determines the status of the n fuses F1, F2, and F3. Does Fn contain a blown fuse (step S17)? In step S17, the control unit 48 determines the time constant (n) through step S16. q If r) is the case, it is determined that the fuse is not blown. q In the case of r), a blown fuse is detected. Here, (n) q r) represents n fuses F1, F2, ... The time constant of the resistor voltage when Fn is not blown.

[0128] It should be noted that the execution of step S17 is equivalent to detecting n fuses F1, F2, ... Does Fn contain a fuse that has blown?

[0129] If the control unit 48 determines that a fuse has blown (S17: Yes), it calculates the values ​​of n fuses F1, F2, ... The number of fuses that blow in Fn (step S18). Divide the time constant determined in step S16 by (q). From r), we can calculate the number of fuses that did not blow, i.e., (nk). By subtracting the calculated number from n, we can calculate the number of fuses that blew, i.e., the integer k.

[0130] If the control unit 48 determines that all fuses have blown (S14: Yes), or after executing step S18, it instructs the notification unit 46 to issue a notification (step S19). In step S19, executed after step S18, the control unit 48, for example, causes the notification unit 46 to output a first notification signal indicating the number calculated in step S18 to a device (not shown). In step S19, executed if the control unit 48 determines that all fuses have blown, the control unit 48, for example, causes the notification unit 46 to output a second notification signal indicating that all fuses have blown to the device.

[0131] If the control unit 48 determines that there is no blown fuse (S17: No), or after executing step S19, the fuse detection process ends. After ending the fuse detection process, the control unit 48 executes step S1 of the fuse detection process again and waits until an IG signal is input.

[0132] In the fuse detection device 11 configured as described above, when the circuit switch 30 is switched to the on state, the resistor voltage decreases. The smaller the time constant of the resistor voltage, the faster the resistor voltage decreases. The time constant is determined based on the n fuses F1, F2, ... The number of fuses that blow in Fn varies. Therefore, the control unit 48 can appropriately detect the number of fuses F1, F2, F3, F4, F5, F6, F7, F8, F9, F1, F2, F1, F3, F1, F2, F3, F1, F3, F4, F5, F6, F1, F2 ... Does Fn contain a fuse that has blown?

[0133] (Implementation Method 2)

[0134] In the fuse detection process of Embodiment 1, the control unit 48 of the microcomputer 37 determines the time constant of the resistor voltage based on multiple detection values. The determination of the time constant can also use a learned model, which has learned the relationship between multiple detection values ​​of the resistor voltage and the time constant of the resistor voltage.

[0135] Hereinafter, regarding Embodiment 2, the differences from Embodiment 1 will be explained. All other structures besides those described later are common to Embodiment 1. Therefore, for structural parts common to Embodiment 1, the same reference numerals as in Embodiment 1 will be used, and descriptions of these structural parts will be omitted.

[0136] <Structure of Microcomputer 37>

[0137] Figure 7This is a block diagram showing the structure of the microcomputer 37 in Embodiment 2. The microcomputer 37 in Embodiment 2 also has the structural parts of the microcomputer 37 in Embodiment 1. The storage unit 47 of the microcomputer 37 also stores a time constant estimation model M (learned model), which learns the relationship between multiple detected values ​​of the resistor voltage and the time constant of the resistor voltage.

[0138] <Explanation of the Time Constant Estimation Model M>

[0139] Figure 8 This is an illustration of the time constant estimation model M. The time constant estimation model M is a machine learning model, such as one incorporating deep learning, composed of a neural network. The time constant estimation model M has an input layer, two intermediate layers, and an output layer. Figure 8 The example shows two intermediate layers. However, the number of intermediate layers is not limited to two; it can also be three or more.

[0140] There are one or more nodes in the input layer, intermediate layer, and output layer. Each node in each layer is coupled along a direction to nodes on one or both sides of the preceding and following layers through desired weights and biases. The number of nodes in the input layer of the time constant estimation model M is consistent with the number of data input to the input layer. In the fuse detection device 11 of Embodiment 2, the data input to the nodes in the input layer is the detected value of the resistance voltage represented by the detection information obtained by the control unit 48.

[0141] Data input to the input layer is output to the nodes of the initial intermediate layer through the nodes constituting the input layer. Data input to the initial intermediate layer is output to the nodes of the next intermediate layer through the nodes constituting that intermediate layer. At this time, the output is calculated using an activation function that includes weights and biases set between the nodes. The calculation using the activation function that includes weights and biases set between the nodes is performed similarly thereafter, and the calculation result is gradually passed to subsequent layers until the calculation result of the output layer is obtained. Here, the data input / output and calculation are performed by the processing element of the control unit 48.

[0142] The output layer outputs the calculation results related to the time constant of the resistor voltage. Specifically, the output time constant is n. c The probability of r and the time constant are (n-1). c The probability of r is equal to the probability of n. The output is related to n. c r, (n-1) c r、 c The probabilities corresponding to r are respectively.

[0143] Regarding the time constant estimation model M, parameters such as the weights and biases of the coupling between nodes are learned using a prescribed learning algorithm. The learning algorithm for various parameters employs, for example, a deep learning algorithm incorporating backpropagation of errors. Training data representing multiple detection values ​​of the resistor voltage and a corresponding time constant is collected, and the learned data is used for training.

[0144] Specifically, multiple detection values ​​representing the training data are input into the input layer of the time constant estimation model M. The results output from the output layer are then evaluated. Then, to make the output of the output layer correspond to the time constant of the training data representation, a prescribed learning algorithm is used to learn various parameters, including the weights and biases between nodes. The result corresponding to the time constant of the training data representation is, for example, the case with the highest probability of corresponding to the time constant of the training data representation.

[0145] It should be noted that the generation of the time constant estimation model M can also be carried out inside the fuse detection device 11, or through a device different from the fuse detection device 11.

[0146] <Determination and handling of time constant>

[0147] Figure 9 This is a flowchart showing the sequence of time constant determination processing. In the circuit breaker detection processing of Embodiment 2, the control unit 48 performs time constant determination processing in step S16. In the time constant determination processing, the control unit 48 first inputs multiple detection values, representing multiple detection information obtained by repeatedly executing step S5 of the circuit breaker detection processing, into the time constant estimation model M (step S21). Thereby, calculations are performed in the time constant estimation model M, and an expression representing AND (n) is output from the output layer. q r), ((n-1) q r) 、(q The probability information of multiple probabilities corresponding to r). As mentioned earlier, the calculations in the time constant estimation model M are performed by the control unit 48.

[0148] After executing step S21, control unit 48 obtains probability information of the time constant output from the output layer of the time constant estimation model M (step S22). Next, control unit 48 determines the time constant of the resistor voltage to, for example, the time constant corresponding to the highest probability among the (n-1) probabilities represented by the probability information obtained in step S22 (step S23). After executing step S23, control unit 48 executes step S17 of the fuse detection process. In steps S17 and S18 of the fuse detection process, the time constant determined in step S23 of the time constant determination process is used.

[0149] Alternatively, the data representing the multiple detection values ​​input to the time constant estimation model M in step S21 and the time constant determined in step S23 can be used as the aforementioned training data. This allows for the relearning of the time constant estimation model M.

[0150] <Effects and Notes>

[0151] The fuse detection device 11 in Embodiment 2 also performs the same function as the fuse detection device 11 in Embodiment 1.

[0152] It should be noted that the data input to the time constant estimation model M is not limited to the detected value represented by the detection information; it can also be the detection information itself, i.e., the value obtained by voltage division through the voltage dividing resistors Rd1 and Rd2 of the voltage detection circuit 34. In this case, the time constant estimation model M is a learned model that has learned the relationship between multiple voltage division values ​​of the resistor voltage and the time constant of the resistor voltage. Moreover, the time constant estimation model M can also be configured to output a single time constant instead of multiple probabilities.

[0153] (Implementation Method 3)

[0154] In implementation method 1, the control unit 48 of the microcomputer 37 determines the time constant, and based on the determined time constant, detects n fuses F1, F2, ... The question asks whether a blown fuse exists within Fn. However, the value used in the fuse detection method for detecting the presence of a blown fuse is not limited to a time constant.

[0155] Hereinafter, regarding Embodiment 3, the differences from Embodiment 1 will be explained. All other structures besides those described later are common to Embodiment 1. Therefore, for structural parts common to Embodiment 1, the same reference numerals as in Embodiment 1 will be used, and the description of these structural parts will be omitted.

[0156] <Overview of Fuse Detection Methods>

[0157] Figure 10 This is an explanatory diagram outlining the fuse detection method in Implementation Method 3. Figure 10 Show Figure 3 The voltage change of the resistor is shown on the lower side. As described in Embodiment 1, the more fuses that blow, the smaller the time constant. The smaller the time constant, the faster the resistor voltage drops. Therefore, when the power supply voltage Vb of the DC power supply 10 is fixed, the resistor voltage value at the point in time after a certain target time has elapsed since the circuit switch 30 was switched on varies depending on the time constant, i.e., the number of fuses that blow.

[0158] In the fuse detection process of Embodiment 1, the control unit 48 of the microcomputer 37 detects whether there is a blown fuse based on the detection value of the resistance voltage detected at the time point when a target time has elapsed since the switching from the indicator circuit switch 30 to the on.

[0159] <Structure of Microcomputer 37>

[0160] The storage unit 47 of the microcomputer 37 in Embodiment 3 stores a resistance voltmeter, which represents the resistance voltage value at a time point after a target time has elapsed since the circuit switch 30 was switched on.

[0161] Figure 11 This is a graph representing a resistance-voltage meter. The resistance-voltage meter shows multiple resistance voltage values ​​corresponding to the power supply voltage of DC power supply 10 and the number of blown fuses. Figure 11 In examples, power supply voltage values ​​could include 14.0V, 13.9V, 13.8V, and 12.0V. The number of fuses that trip could be 0, 1, or... (n-1). The resistance voltage value displayed by the resistance voltmeter is obtained through actual measurement or simulation.

[0162] <Fuse Detection and Handling>

[0163] Figure 12 and Figure 13 This is a flowchart illustrating the sequence of the fuse detection process. Similar to Embodiment 1, the control unit 48 performs the fuse detection process when the circuit switch 30 and the discharge switch 32 are respectively open and closed. A portion of the fuse detection process in Embodiment 3 is common to a portion of the fuse detection process in Embodiment 1. Therefore, in the fuse detection process of Embodiment 3, steps common to the steps in the fuse detection process of Embodiment 1 are labeled with the same numbers as in Embodiment 1, and detailed descriptions of these steps are omitted. Specifically, detailed descriptions of steps S1, S3, S4, S12, S13, and S19 are omitted.

[0164] The microcomputer 37 stores a first voltage value and a second voltage value in its storage unit 47. The first voltage value is processed as the power supply voltage value of the DC power supply 10. The second voltage value is processed as the resistor voltage value at a time point after a target time has elapsed since the circuit switch 30 was switched on. The first voltage value and the second voltage value are updated by the control unit 48.

[0165] In the fuse detection process, if the control unit 48 determines that an IG signal has been input to the input unit 44 (S1: Yes), it executes step S3. By executing steps S3 and S4, the control unit 48 switches the circuit switch 30 and the discharge switch 32 to on and off, respectively. As mentioned earlier, when the circuit switch 30 is on, the resistor voltage decreases from the power supply voltage of the DC power supply 10 over time.

[0166] After executing step S4, control unit 48 instructs timer 45 to start measurement (step S31). Timer 45 then measures the elapsed time from the point in time when measurement was instructed to begin, i.e., from the point when circuit switch 30 was switched on. After executing step S31, control unit 48 obtains detection information representing the detected resistance voltage from A / D conversion unit 43 (step S32). This detected value is the resistance voltage value detected immediately after circuit switch 30 is switched on, and it is substantially the same as the power supply voltage value of DC power supply 10. Execution of step S32 is equivalent to obtaining the power supply voltage value of DC power supply 10.

[0167] Next, the control unit 48 updates the first voltage value to the detection value represented by the detection information obtained in step S32 (step S33). After executing step S33, the control unit 48 determines whether the measurement time measured by the timer 45 is greater than or equal to the target time (step S34). If the control unit 48 determines that the measurement time is less than the target time (S34: No), it executes step S34 again and waits until the measurement time reaches the target time. If the control unit 48 determines that the measurement time is greater than or equal to the target time (S34: Yes), it obtains the detection information from the A / D conversion unit 43 (step S35). The detection value represented by the detection information obtained in step S35 is the detection value of the resistor voltage at the point in time from when the circuit switch 30 was switched on to when the target time has elapsed. The target time is equivalent to a predetermined time. Next, the control unit 48 updates the second voltage value to the detection value of the resistor voltage represented by the detection information obtained in step S35 (step S36).

[0168] After executing step S36, the control unit 48 instructs the timer 45 to end the measurement (step S37). Thus, the timer 45 ends the time measurement. After executing step S37, the control unit 48 sequentially executes steps S12 and S13. As a result, the circuit switch 30 and the discharge switch 32 are switched to open and closed, respectively. As described in Embodiment 1, when the circuit switch 30 is switched to open, the current flow through the circuit resistor 31 stops. When the discharge switch 32 is closed, the n capacitors C1, C2, ... Cn is discharged through discharge resistor 33.

[0169] After executing step S13, control unit 48 determines all fuses, i.e., n fuses F1, F2, and F3, based on the first voltage value, i.e., the detection value represented by the detection information obtained in step S32. 1. Whether Fn is blown (step S38). In step S38, the control unit 48 determines whether all fuses are blown based on whether the first voltage value is 0. As mentioned above, the first voltage value is the resistance voltage value detected immediately after the circuit switch 30 is switched on. If the first voltage value is 0V, the control unit 48 determines that all fuses are blown. If the first voltage value is not 0V, the control unit 48 determines that all fuses are not blown.

[0170] If the control unit 48 determines that all fuses have not blown (S38: No), it determines whether the power supply voltage of the DC power supply 10 has changed from the start of measurement by the timer 45 until the target time has elapsed (step S39). If the power supply voltage of the DC power supply 10 has changed from the time the circuit switch 30 is switched on until the target time has elapsed, the control unit 48 cannot obtain appropriate detection information, i.e., an appropriate detection value. Therefore, step S39 is executed.

[0171] When the power supply voltage rises, the difference between the first voltage value and the second voltage value is small. Therefore, as a first method for detecting the rise in power supply voltage, a method for determining whether the difference between the first voltage value and the second voltage value is less than a first threshold can be listed. As described in Embodiment 1, the first threshold is a constant value and is preset. When the generator 20 generates electricity, or when a high-current load supplied with a large current stops operating, the power supply voltage rises. Therefore, as a second method for detecting the rise in power supply voltage, a method for determining whether the generator 20 or the high-current load is operating can be listed, for example, based on a status signal indicating the operating state of the generator 20 or the high-current load. As described in Embodiment 1, the high-current load is n loads U1, U2, ... One of 、Un.

[0172] When the power supply voltage drops, the difference between the first voltage value and the second voltage value becomes large. Therefore, as a first method for detecting the drop in power supply voltage, a method for determining whether the difference between the first voltage value and the second voltage value is greater than or equal to a second threshold can be listed. As described in Embodiment 1, the second threshold is a constant value and is preset. The second threshold is greater than or equal to the first threshold. When the generator 20 stops generating electricity or a high-current load is operating, the power supply voltage drops. Therefore, as a second method for detecting the drop in power supply voltage, a method for determining whether the generator 20 or the high-current load has stopped operating can be listed, for example, based on the aforementioned state signal.

[0173] If the control unit 48 determines that the power supply voltage has changed (S39: Yes), it executes step S3 to update the first voltage value and the second voltage value again. If the control unit 48 determines that the power supply voltage has not changed (S39: No), it determines, in the resistance voltmeter, the resistance voltage value closest to the second voltage value among the n resistance voltage values ​​corresponding to the power supply voltage value closest to the first voltage value (step S40). Next, the control unit 48 refers to the number of blown fuses in the resistance voltmeter (step S41). In step S41, the number of fuses referred to by the control unit 48 is the number of fuses corresponding to the resistance voltage values ​​determined in step S40.

[0174] Next, based on the number of fuses referenced in step S41, the control unit 48 determines the number of fuses F1, F2, ... Whether there is a blown fuse among Fn (step S42). In step S42, if the number of fuses referenced in step S41 is different from 0, the control unit 48 detects that there is a blown fuse. If the number of fuses referenced in step S41 is 0, the control unit 48 determines that there is no blown fuse.

[0175] It should be noted that the execution of step S42 is equivalent to detecting the circuit breakers F1, F2, and F3 in the n fuses. Does Fn contain a fuse that has blown?

[0176] As described in Embodiment 1, the more fuses that blow, the lower the time constant of the resistor voltage and the faster the resistor voltage drops. Therefore, in Figure 11 In the resistance-voltage table shown, with the power supply voltage value fixed, the more fuses that blow, the lower the resistance voltage value. Therefore, the case where the number of fuses referenced in step S41 is different from 0 refers to the case where the second voltage value is lower than the resistance voltage value when the number of blown fuses is 0.

[0177] If the control unit 48 determines that all fuses have blown (S38: Yes), or if it determines that some fuses have blown (S42: Yes), it executes step S19. In step S19, executed when the control unit 48 determines that some fuses have blown, the control unit 48, for example, causes the notification unit 46 to output a first notification signal to the device indicating the number of fuses referenced in step S41. In step S19, executed when the control unit 48 determines that all fuses have blown, the control unit 48, for example, causes the notification unit 46 to output a second notification signal to the device indicating that all fuses have blown.

[0178] If the control unit 48 determines that there is no blown fuse (S42: No), or after executing step S19, the fuse detection process ends. After ending the fuse detection process, the control unit 48 executes step S1 of the fuse detection process again and waits until an IG signal is input.

[0179] The fuse detection device 11 in Embodiment 3 also performs the same effect as the fuse detection device 11 in Embodiment 1.

[0180] (Implementation Method 4)

[0181] In implementation method 1, n capacitors C1, C2, ... In the discharge circuit used for Cn discharge, n diodes D1, D2, and D3 are used. Dn. However, the structure of the discharge circuit is not limited to using n diodes D1, D2, Dn. The structure of Dn.

[0182] Hereinafter, regarding Embodiment 4, the differences from Embodiment 1 will be explained. All other structures besides those described later are common to Embodiment 1. Therefore, for structural parts common to Embodiment 1, the same reference numerals as in Embodiment 1 will be used, and the description of these structural parts will be omitted.

[0183] <Structure of Power System 1>

[0184] Figure 14 This is a block diagram showing the main structure of the power system 1 in Embodiment 4. In Embodiment 4, similar to Embodiment 1, the fuse detection device 11 is connected to n fuses F1, F2, F3, F4, F5, F6, F7, F8, F9, F1, F1, F2, F1, F1, F2, F1, F1, F2, F1, F3, F1, F1, F2 ... One end of the downstream side of Fn. The fuse detection device 11 is also connected to one end of the DC power supply 10.

[0185] <Structure of the fuse detection device 11>

[0186] The fuse detection device 11 in embodiment 4 has a structure that includes n diodes D1, D2, ... Other structural components besides Dn. Besides the n diodes D1, D2, ... The connections of the other structural parts besides Dn are the same as in Embodiment 1, except for one end of the discharge switch 32. In Embodiment 4, the fuse detection device 11 replaces n diodes D1, D2, ... Dn has a diode 38.

[0187] The anode of diode 38 is connected to one end of DC power supply 10. The cathode of DC power supply 10 is connected to one end of discharge switch 32.

[0188] The first switching circuit 35 and the second switching circuit 36 ​​function in the same way as in Embodiment 1. Therefore, when the circuit switch 30 is open, the second switching circuit 36 ​​switches the discharge switch 32 to the on state. When the circuit switch 30 and the discharge switch 32 are respectively open and on, when the capacitor Ci has accumulated power, the current flows from one end of the capacitor Ci in the order of fuse Fi, diode 38, discharge switch 32, discharge resistor 33 and the other end of the capacitor Ci, and the capacitor Ci discharges.

[0189] Therefore, when n capacitors C1, C2, ... When the discharge switch 32 is switched on while Cn is charged with electricity, current is output from the cathode of diode 38. The current output from the cathode of diode 38 flows through the discharge switch 32 and the discharge resistor 33.

[0190] <Effects and Notes>

[0191] The fuse detection device 11 in Embodiment 4 also performs the same function as the fuse detection device 11 in Embodiment 1.

[0192] It should be noted that the structure of the discharge circuit of the fuse detection device 11 in embodiments 2 and 3 is not limited to using n diodes D1, D2, ... The structure of Dn. The fuse detection device 11 in each of embodiments 2 and 3 can also be configured in the same way as the fuse detection device 11 in embodiment 4.

[0193] <Variation Example>

[0194] In the fuse detection process of embodiments 1 to 4, the timing of executing step S2, that is, the timing of detecting whether a fuse has blown, is not limited to the moment when the IG signal is input to the input unit 44. For example, step S2 may also be executed at the moment when a detection indication signal indicating detection is input to the input unit 44. The detection indication signal is output, for example, from a device operated by a vehicle dealer.

[0195] In embodiments 1 to 4, the fuse detection device 11 may also include a power supply detection circuit for detecting the power supply voltage of the DC power supply 10. In this case, the voltage value detected by the power supply detection circuit is used as the power supply voltage value.

[0196] The discharge circuit in embodiments 1 to 4 can also be a series circuit in which the discharge switch 32 is connected in series with the discharge resistor 33 and connected to n capacitors C1, C2, ... The circuit between the two ends of each of C1 and Cn. In this case, when the n discharge switches 32 are switched on, the n capacitors C1, C2, and Cn... Cn discharge.

[0197] In embodiments 1-4, n capacitors C1, C2, ... The capacitance of each of the n fuses F1, F2, and Cn can also be different from at least one of the other fuses. Even in this case, in the n fuses F1, F2, and Cn, When one of the fuses F1, F2, ..., Fn blows, the time constant of the resistor voltage also decreases, thus enabling detection of the blown fuses F1, F2, ... Does Fn contain a fuse that has blown?

[0198] In embodiments 1 to 4, the position of the circuit switch 30 is not limited to the upstream position of the circuit resistor 31, but can also be the downstream position of the circuit resistor 31. Similarly, the position of the discharge switch 32 is not limited to the upstream position of the discharge resistor 33, but can also be the downstream position of the discharge resistor 33.

[0199] In embodiments 1 to 4, the structure of the DC power supply 10 is not limited to having both a generator 20 and a battery 21, and may also be a structure that does not include the generator 20.

[0200] In embodiments 1 to 4, the structure of the voltage detection circuit 34 is not limited to using voltage divider resistors Rd1 and Rd2. For example, the voltage detection circuit 34 may also include: a current output section that outputs a current proportional to the voltage value between the two ends of the circuit resistor 31 (i.e., the resistor voltage value); and a current resistor through which the current output from the current output section flows. In this case, the voltage value between the two ends of the current resistor is output to the microcomputer 37 as detection information.

[0201] It should be considered that the disclosed embodiments 1-4 are illustrative in all respects and not restrictive. The scope of the invention is defined not by the foregoing but by the claims, and is intended to include all modifications within the meaning and scope equivalent to the claims.

[0202] Label Explanation

[0203] 1 Power System

[0204] 10 DC power supply

[0205] 11. Fuse Detection Device

[0206] 20 generators

[0207] 21 Storage batteries

[0208] 30 Circuit Switch

[0209] 31 Circuit Resistance

[0210] 32 Discharge Switch

[0211] 33 Discharge resistor

[0212] 34 Voltage Detection Circuit

[0213] 35 First switching circuit

[0214] 36 Second switching circuit

[0215] 37 Microcomputer

[0216] 38 diode

[0217] 41 First Output Section

[0218] 42 Second Output Section

[0219] 43 A / D Conversion Section

[0220] 44 Input Section

[0221] 45 Timer

[0222] 46 Notification Department

[0223] 47 Storage Department

[0224] 48. Control Department (Processing Department)

[0225] 49 Internal Bus

[0226] A storage medium

[0227] C1, C2, Cn capacitor

[0228] D1, D2 Dn diode

[0229] F1, F1, Fn fuse

[0230] M-time constant estimation model (learned model)

[0231] P Computer Program

[0232] Q1, Q2, Qn power supply switch

[0233] Rd1 and Rd2 voltage divider resistors

[0234] U1, U2, Un load.

Claims

1. A fuse detection device for detecting whether a fuse has blown among a plurality of fuses, wherein the plurality of fuses are respectively disposed in a plurality of current paths shunt from one end of a DC power supply, wherein, The fuse detection device includes: Multiple capacitors are connected to one downstream end of each of the multiple fuses; Circuit switches and circuit resistors are input with multiple currents flowing through the plurality of capacitors; and Processing Department, Execute Processing The processing unit instructs the circuit switch to be switched on. The processing unit obtains the detected value of the resistance voltage across the circuit resistance as time passes, when the circuit switch is on. The processing unit detects whether there is a blown fuse among the plurality of fuses based on the obtained detection values.

2. The fuse detection device according to claim 1, wherein, The processing unit acquires the detected value of the resistor voltage over time while the circuit switch is on. The processing unit determines the time constant of the resistor voltage based on multiple acquired detection values. The processing unit detects whether there is a blown fuse among the plurality of fuses based on a determined time constant.

3. The fuse detection device according to claim 2, wherein, The processing unit determines whether the power supply voltage of the DC power supply has changed during the acquisition of the plurality of detection values.

4. The fuse detection device according to claim 2 or 3, wherein, The processing unit inputs the acquired multiple detection values ​​into the learned model, which has learned the relationship between the multiple detection values ​​of the resistor voltage and the time constant of the resistor voltage. The processing unit determines the time constant of the resistor voltage based on the output of the learned model.

5. The fuse detection device according to claim 1, wherein, The processing unit obtains the power supply voltage value of the DC power supply. The processing unit obtains the detected value of the resistor voltage at a time point after a predetermined time has elapsed since the circuit switch was switched on. The processing unit detects whether there is a blown fuse among the plurality of fuses based on the obtained power supply voltage value and the detection value.

6. The fuse detection device according to claim 5, wherein, The processing unit determines whether the power supply voltage of the DC power supply has changed from the time the circuit switch is switched on to the time the specified time has elapsed.

7. The fuse detection device according to any one of claims 1 to 3, wherein, The fuse detection device includes: A diode, with its anode connected to one end of the DC power supply; and The discharge switch and discharge resistor allow current to flow from the cathode of the diode. When the discharge switch is turned on, current flows from one end of the capacitor in the order of the fuse, diode, discharge resistor, and the other end of the capacitor.

8. The fuse detection device according to any one of claims 1 to 3, wherein, The fuse detection device includes: Multiple diodes, with their anodes connected to one end of the downstream side of each of the multiple fuses; and The discharge switch and discharge resistor carry current flowing from the cathodes of multiple diodes. When the discharge switch is turned on, current flows from one end of the capacitor in the order of the diode, the discharge resistor, and the other end of the capacitor.

9. The fuse detection device according to any one of claims 1 to 3, wherein, The processing unit determines whether all of the multiple fuses have blown based on whether the obtained detection value indicates 0V.

10. A fuse detection method, wherein a computer uses a circuit to detect whether a blown fuse exists among a plurality of fuses, the circuit comprising: a plurality of capacitors connected to one downstream end of each of the plurality of fuses, the plurality of fuses being respectively configured in a plurality of current paths shunt from one end of a DC power supply; and a circuit switch and a circuit resistor, input to a plurality of currents flowing through the plurality of capacitors, wherein, The computer performs the following steps: Indicates the switching of the circuit switch to the on direction; Obtain the detected value of the resistance voltage across the circuit resistor as time passes, with the circuit switch on; and Based on the obtained detection values, it is used to detect whether there is a blown fuse among the plurality of fuses.

11. A computer program product that uses a circuit to detect whether a blown fuse exists among a plurality of fuses, the circuit comprising: a plurality of capacitors connected to one downstream end of each of the plurality of fuses, the plurality of fuses being respectively configured in a plurality of current paths shunt from one end of a DC power supply; and a circuit switch and a circuit resistor, input to the plurality of currents flowing through the plurality of capacitors, wherein, The computer program product is used to cause the computer to perform the following steps: Indicates the switching of the circuit switch to the on direction; Obtain the detected value of the resistance voltage across the circuit resistor as time passes, with the circuit switch on; and Based on the obtained detection values, it is used to detect whether there is a blown fuse among the plurality of fuses.

Images