Blown fuse detection apparatus, blown fuse detection method, and computer program
A plurality of fuses (F 1 , F 2 , . . . , and Fn) are respectively disposed on current paths for a plurality of currents branched from one end of a DC power source ( 10 ). In a blown fuse detection apparatus ( 11 ), ends on one side of a plurality of capacitors (C 1 , C 2 , . . . , Cn) are respectively connected to the ends on the downstream side of the plurality of fuses (F 1 , F 2 , . . . , and Fn). A plurality of currents that have flowed through the capacitors (C 1 , C 2 , . . . , Cn) are input to a circuit switch ( 30 ) and a circuit resistor ( 31 ). A microcomputer ( 37 ) instructs that the circuit switch ( 30 ) be switched on, obtains a detected value of a resistance voltage, and detects, based on the obtained detected value, whether or not there is a blown fuse among the fuses (F 1 , F 2 , . . . , and Fn).
1 . A blown fuse detection apparatus for detecting whether or not there is a blown fuse among a plurality of fuses respectively disposed on a plurality of current paths branched from one end of a DC power source, the blown fuse detection apparatus comprising:
a plurality of capacitors that are respectively connected to ends on a downstream side of a corresponding one of the plurality of fuses;
a current path connected to a downstream side of each of the plurality of capacitors;
a circuit switch disposed on the current path and configured to open and close the current path;
and a circuit resistor to which a plurality of currents that have flowed through the plurality of capacitors are input, the circuit switch interposed between the downstream side of each of the plurality of capacitors and the circuit resistor; and
a processing unit that executes processing,
wherein the processing unit is configured to detect a blown fuse by executing the following steps:
instructing the circuit switch to be switched on,
obtaining a detected value of a resistance voltage between two ends of the circuit resistor that decreases with a lapse of time in a state where the circuit switch is on, and
determining, based on the obtained detected value, whether or not there is a blown fuse among the plurality of fuses.
2 . The blown fuse detection apparatus according to claim 1 ,
wherein the processing unit
obtains the detected value of the resistance voltage overtime in a state where the circuit switch is on,
determines a time constant of the resistance voltage based on the plurality of obtained detected values, and
detects, based on the determined time constant, whether or not there is a blown fuse among the plurality of fuses.
3 . The blown fuse detection apparatus according to claim 2 ,
wherein the processing unit determines whether or not a power source voltage of the DC power source changed while the plurality of detected values were obtained.
4 . The blown fuse detection apparatus according to claim 2 ,
wherein the processing unit
inputs the plurality of obtained detected values to a learned model that has been trained on a relation between a time constant of the resistance voltage and a plurality of detected values of the resistance voltage, and
determines the time constant of the resistance voltage based on output from the learned model.
5 . The blown fuse detection apparatus according to claim 1 ,
wherein the processing unit
obtains a power source voltage value of the DC power source,
obtains a detected value of the resistance voltage at a time point when a predetermined time has elapsed since the circuit switch was switched on, and
detects, based on the obtained power source voltage value and detected value, whether or not there is a blown fuse among the plurality of fuses.
6 . The blown fuse detection apparatus according to claim 5 ,
wherein the processing unit determines whether or not the power source voltage of the DC power source changed during a period from when the processing unit instructed that the circuit switch be switched on until when the predetermined time elapsed.
7 . The blown fuse detection apparatus according claim 1 , further comprising:
a diode whose anode is connected to the one end of the DC power source; and
a discharge switch and a discharge resistor through which a current output from a cathode of the diode flows,
wherein, when the discharge switch is on, a current flows from ends on one side of the capacitors through the fuse, the diode, the discharge resistor, and ends on the other side of the capacitors in the stated order.
8 . The blown fuse detection apparatus according to claim 1 , further comprising:
a plurality of diodes whose anodes are respectively connected to ends on a downstream side of the plurality of fuses; and
a discharge switch and a discharge resistor through which a current output from cathodes of the plurality of diodes flow,
wherein, when the discharge switch is on, a current flows from ends on one side of the capacitors through the diodes, the discharge resistor, and ends on the other side of the capacitors in the stated order.
9 . The blown fuse detection apparatus according to claim 1 ,
wherein the processing unit determines whether or not all of the plurality of fuses are blown, based on whether or not the obtained detected value indicates 0 V.
10 . A blown fuse detection method for detecting, by a computer, whether or not there is a blown fuse among a plurality of fuses respectively disposed on a plurality of current paths branched from one end of a DC power source, the method includes the steps of:
providing a plurality of capacitors that are respectively connected to ends on a downstream side of a corresponding one of the plurality of fuses;
providing a current path connected to a downstream side of each of the plurality of capacitors;
providing a circuit switch disposed on the current path and configured to open and close the current path;
providing a circuit resistor to which a plurality of currents that have flowed through the plurality of capacitors are input, the circuit switch interposed between the downstream side of each of the plurality of capacitors and the circuit resistor
wherein the method includes
a step of instructing, by the computer, that the circuit switch be switched on,
a step of obtaining, by the computer, a detected value of a resistance voltage between two ends of the circuit resistor that decreases with a lapse of time in a state where the circuit switch is on, and
a step of determining, by the computer, based on the obtained detected value, whether or not there is a blown fuse among the plurality of fuses.
11 . A computer program product for detecting whether or not there is a blown fuse among a plurality of fuses respectively disposed on a plurality of current paths branched from one end of a DC power source, in a circuit that includes a plurality of capacitors that are respectively connected to ends on a downstream side of the plurality of fuses, and a circuit switch and a circuit resistor to which a plurality of currents that have flowed through the plurality of capacitors are input,
wherein the computer program product comprises a non-transitory, machine-readable medium storing instructions which, when executed by at least one programmable processor, causes at least one programmable processor to perform operations comprising:
a step of instructing that the circuit switch be switched on,
a step of obtaining a detected value of a resistance voltage between two ends of the circuit resistor that decreases with a lapse of time in a state where the circuit switch is on, and
a step of detecting, based on the obtained detected value, whether or not there is a blown fuse among the plurality of fuses.