JPH05115101A - Auxiliary power supply for vehicle - Google Patents

Abstract

PURPOSE:To prevent secondary failure upon occurrence of ground fault by detecting voltage across a filter capacitor and interrupting a circuit breaker if thus detected voltage does not exceed a reference level upon elapse of a sufficient time after start of charging of the filter capacitor. CONSTITUTION:Under a state where a filter capacitor 8 is not yet charged and the voltage Vf across the filter capacitor 8 is lower than a reference level Vfr while the overhead line voltage Vd is normal and higher than a reference level Vdr, a high speed circuit breaker 4 is turned ON by a high speed circuit breaker ON signal ION to start charging of the filter capacitor 8. When a detection signal Vf of a capacitor voltage sensor 14 does not exceed the reference level Vfr because of ground fault, frequency signal of a logic circuit 33 remains in H level even upon elapse of a delay time and a high speed circuit breaker OFF signal IOFF is outputted from a delay circuit 34. Consequently, the high speed circuit breaker 4 is turned OFF to interrupt current flow to the grounded part thus preventing secondary failure such as burning of charging resistor RC or breakdown of grounded part.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle auxiliary power supply device capable of preventing a secondary failure from occurring in the event of a ground fault.

[0002]

2. Description of the Related Art FIG. 2 is a circuit diagram showing a conventional auxiliary power supply device for a vehicle, which is described, for example, on pages 1147 to 1148 of "The 61st Annual Meeting of the Institute of Electrical Engineers of Japan". In the figure, 1 is an overhead line for supplying DC 1500V,
1a is a pantograph collecting current from the overhead line 1, 2, 3,
Reference numerals 4, 5, and 6 are disconnecting switches, fuses, high-speed circuit breakers (circuit breakers), resistors, and filter reactors connected in series to the pantograph 1. 7 is an initial charging circuit composed of a charging resistor RC and a thyristor BTH connected in parallel with each other, 8 is a filter capacitor charged by the initial charging circuit 7, 9 is a discharging contactor for discharging the filter capacitor 8, and 10 is a filter A DC chopper circuit for waveform-processing the charging voltage of the capacitor 8, 11 is an inverter for converting the output voltage of the DC chopper circuit 10 into three-phase AC, and 12 is a transformer / AC filter capacitor for transforming the three-phase AC from the inverter 11. is there.

Reference numeral 13 is a high speed circuit breaker 4, an initial charging circuit 7,
A control circuit for controlling the discharge contactor 9, the DC chopper circuit 10 and the inverter 11, a start command circuit 20 for giving a command to the high speed circuit breaker 4, the initial charging circuit 7 and the discharge contactor 9, and a transformer / AC filter. reference and the output voltage detector 21 that outputs a detection signal V _t by detecting the output voltage of the capacitor 12, the output voltage reference value generator 22 for generating a reference value V _tr of the detection signal V _t, the detection signal V _t A voltage controller 23 for comparing with the value V _tr , a chopper output voltage detector 24 for detecting the output voltage of the DC chopper circuit 10 and outputting a detection signal V _c, and a constant for generating a reference value V _cr of the detection signal V _c. A voltage reference value generator 25, a voltage controller 26 to which a detection signal V _c , a reference value V _cr and an output signal of the voltage controller 23 are input, and an output signal of the voltage controller 26. DC chopper circuit based on
Chopper controller 27 for controlling 0 and frequency reference value _fr
A frequency reference value generator 28 for generating
_The inverter controller 29 controls the inverter 11 based on _r .

Under the control of the control circuit 13, the conventional auxiliary power supply device for a vehicle shown in FIG. 2 supplies the DC power collected from the pantograph 1a to the DC chopper circuit 10, the inverter 11 and the transformer / AC filter. The capacitor 12 converts the AC power. The operation is divided into an initial charging operation, a steady operation, and a stopping operation, and these operations will be described below.

First, the high speed circuit breaker ON signal I _ON is output from the start command circuit 20, and the high speed circuit breaker 4 is turned on. At this time, the thyristor BTH is off,
The filter capacitor 8 is charged via the charging resistor RC. After the charging is completed, in order to minimize the loss due to Joule heat in the charging resistor RC, the command signal T is output from the start command circuit 20 and the thyristor BTH is turned on. As a result, the charging resistor RC is short-circuited and the filter reactor 6 and the filter capacitor 8 form an input filter circuit. The above is the initial charging operation. Then, the DC chopper circuit 10 is gradually activated and shifts to a steady operation, and the inverter 11 and the transformer / AC filter capacitor 12 convert DC power into AC power.
The description of the stop operation is omitted.

By the way, in order to turn on the thyristor BTH in the initial charging operation, the filter capacitor 8
Is assumed to be fully charged. Therefore, in many cases, the start command circuit 20 is made to proceed with the start sequence on condition that the voltage across the filter capacitor 8 has become sufficiently high.

[0007]

Since the conventional auxiliary power supply device for a vehicle is constructed as described above, when a ground fault accident due to dielectric breakdown, element failure or the like occurs, the charging current flows to the ground fault portion. Therefore, the filter capacitor 8 is not charged. Therefore, the start-up sequence does not proceed, the thyristor BTH is not turned on, and the ground fault current is generated by the charging resistor RC.
There is a problem in that secondary failure such as burnout of the charging resistor RC and breakage of the ground fault occurs.

The present invention has been made to solve the above problems, and an object thereof is to obtain an auxiliary power supply device for a vehicle capable of preventing a secondary failure in the event of a ground fault.

[0009]

A vehicle auxiliary power supply device according to the present invention detects a voltage across a filter capacitor and outputs a detection signal proportional to this voltage, and a voltage of an overhead line. An overhead wire voltage sensor that outputs a detection signal proportional to this voltage, and a first voltage comparator that outputs a first comparison signal that becomes active when the detection signal of the capacitor voltage sensor is smaller than a first reference value. And a second voltage comparator that outputs a second comparison signal that becomes active when the detection signal of the overhead wire voltage sensor is larger than a second reference value, and an active state when the breaker is turned on. And a first comparison signal and a second comparison signal are input, and a logic circuit that outputs a logic signal that becomes active only when all of these three signals are active, and a logic signal The output signal when the logic signal changes to non-active as soon as it is input changes to non-active immediately, and the output signal when the logic signal changes to active is that the logic signal is active for a predetermined time longer than the charging time of the filter capacitor. A closing delay circuit that changes to an active state only when it is maintained is provided, and the circuit breaker is turned off when the output signal of the closing delay circuit becomes active.

[0010]

In the present invention, the voltage across the filter capacitor is detected by the capacitor voltage sensor,
If the voltage across the filter capacitor does not become higher than the reference value when charging of the filter capacitor has started and sufficient time has elapsed, the circuit breaker is cut off.

[0011]

EXAMPLES Example 1. FIG. 1 is a circuit diagram showing a first embodiment of the present invention, in which 1, 1a, 2 to 12 and 21 to 29 are the same as those described above, 13A and 20A correspond to a control circuit 13 and a start command circuit 20. Is. 14 is a capacitor voltage sensor that constantly detects the voltage across the filter capacitor 8 and outputs a detection signal V _f proportional to this voltage, and 15 is connected to the connection point of the fuse 3 and the high speed circuit breaker 4 and the overhead line 1 Is an overhead line voltage sensor that constantly detects the voltage of and outputs a detection signal V _d proportional to this voltage. 16
Indicates to the start command circuit 20A the high speed circuit breaker off command signal I
A circuit breaker command circuit for outputting _OFF to break the high-speed circuit breaker 4, that is, circuit breaker command means, including the following elements 31 to 31:
It consists of 36.

Reference numeral 31 is a voltage comparator (first voltage comparator) for comparing the detection signal V _f of the capacitor voltage sensor 14 with a reference value V _fr (first reference value), and its output signal is a first voltage comparator. When the detection signal V _f is smaller than the reference value V _fr , the comparison signal becomes H level (active), and when it is larger, it becomes L level (non-active). Reference _numeral 32 denotes a voltage comparator (second voltage comparator) for comparing the detection signal V _d of the overhead wire voltage sensor 15 with a reference value V _dr (second reference value), and a second comparison signal which is an output signal thereof. Is the detection signal V
_{When d} is larger than the reference value V _dr , it becomes H level (active), and when _d is smaller than L level (non-active).
become. Reference numeral 33 denotes an AND circuit (logical circuit) which performs a logical product of the high speed circuit breaker ON signal I _ON which becomes H level (active) when the high speed circuit breaker 4 is _ON and the first and second comparison signals. The output of the logic signal is H level (only when the voltage of the filter capacitor 8 is lower than the reference value, the overhead wire voltage is higher than the reference value, and the high speed circuit breaker 4 is turned on. Become active).

Reference numeral 34 is a closing delay circuit for delaying the logic signal. When the logic signal changes to the L level (nonactive), the output signal immediately changes to the L level (nonactive), but the logic signal changes to the H level. (Active)
When the output signal changes to the delay time T _d
H level (active) only when H level is maintained during
Changes to. Here, the delay time T _d is set to a time sufficiently longer than the charging time of the filter capacitor 8,
Further, the output signal of the closing delay circuit 34 constitutes a high speed circuit breaker off command signal I _OFF , and turns off the high speed circuit breaker 4 to the start command circuit 20A when it is at the H level (active). Reference numerals 35 and 36 are a capacitor voltage reference value generator and an overhead wire voltage reference value generator that generate reference values V _fr and V _dr used for comparison of the voltage comparators 31 and 32.

Next, the operation of the first embodiment of the present invention shown in FIG. 1 will be described. First, the filter capacitor 8 is uncharged, the voltage across it is lower than the reference value, and
When the overhead wire voltage is normal and higher than the reference value, the high speed circuit breaker 4 is turned on by the high speed circuit breaker ON signal I _ON ,
The charging of the filter capacitor 8 is started. At this time,
Since the high speed circuit breaker ON signal I _ON changes to H level,
The logic signal (the output signal of the AND circuit 33) changes to the H level. When the filter capacitor 8 is normally charged without the occurrence of the ground fault, the detection signal V _f of the capacitor voltage sensor 14 becomes higher than the reference value V _fr , so that the logic signal is generated before the delay time T _d elapses from the start of charging. Changes to L level. Therefore, the closing delay circuit 34 does not output the high speed circuit breaker off command signal I _{OF F.}

On the other hand, when the ground fault occurs and the filter capacitor 8 is not normally charged and the detection signal V _f of the capacitor voltage sensor 14 does not become higher than the reference value V _fr , the delay time T _d elapses. After that, the logic signal remains at the H level, and the delay circuit 34 outputs the high-speed circuit breaker off command signal I _OFF . As a result, the high-speed circuit breaker 4 is turned off, the current to the ground fault part is cut off, and it is possible to prevent the occurrence of secondary failure such as burnout of the charging resistor RC and destruction of the ground fault part.

Although the occurrence of the ground fault is not particularly displayed in the first embodiment, it may be displayed on a display or the like for warning.

Embodiment 2. In the first embodiment, the DC chopper circuit 10 and the inverter 11 are used as the vehicle auxiliary power supply device, but the DC chopper circuit 10 is used.
There may be no inverter, and only a DC voltage control method other than the chopper method may be used.

[0018]

As described above, according to the present invention, a capacitor voltage sensor that detects the voltage across the filter capacitor and outputs a detection signal proportional to this voltage, and a voltage on the overhead wire are proportional to this voltage. Voltage sensor that outputs a detection signal that outputs, a first voltage comparator that outputs a first comparison signal that becomes active when the detection signal of the capacitor voltage sensor is smaller than a first reference value, and an overhead line voltage sensor A second voltage comparator that outputs a second comparison signal that becomes active when the detection signal of is greater than a second reference value, and a signal that becomes active when the breaker is turned on. And a second comparison signal and a logic circuit that outputs a logic signal that becomes active only when all of these three signals are active, and a logic signal that is input The output signal when the logic signal changes to non-active immediately changes to non-active and the output signal when the logic signal changes to active is when the logic signal remains active for a predetermined time longer than the charging time of the filter capacitor. A vehicle that can prevent secondary failures in the event of a ground fault because the circuit breaker is turned off when the output signal of the circuit is activated. There is an effect that the auxiliary power supply device for use is obtained.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing a first embodiment of the present invention.

FIG. 2 is a circuit diagram showing a conventional vehicle auxiliary power supply device.

[Explanation of symbols]

1 overhead line 4 high speed circuit breaker 8 filter capacitor 14 capacitor voltage sensor 15 overhead line voltage sensor 16 circuit breaker command circuit 31, 32 voltage comparator 33 AND circuit 34 closing delay circuit V _f , V _d detection signal V _fr , V _dr reference value

Claims (1)

[Claims] 1. A filter capacitor charged by electric power collected from an overhead wire and a current that is selectively turned on and off and cut off from a current supplied to the filter capacitor from the overhead wire when turned off. In a vehicle auxiliary power supply device including a circuit breaker, a capacitor voltage sensor that detects a voltage across the filter capacitor and outputs a detection signal proportional to this voltage; and a voltage of the overhead wire that is proportional to this voltage. An overhead wire voltage sensor that outputs a detection signal that outputs, a first voltage comparator that outputs a first comparison signal that becomes active when the detection signal of the capacitor voltage sensor is smaller than a first reference value, and the overhead wire A second voltage comparator which outputs a second comparison signal which becomes active when the detection signal of the voltage sensor is larger than the second reference value; A signal that becomes active when the circuit breaker is turned on, the first comparison signal and the second comparison signal are input, and a logic signal that becomes active only when all of these three signals are active is output. And a logic circuit for inputting the logic signal, the output signal when the logic signal changes to non-active immediately changes to non-active, and the output signal when the logic signal changes to active is the logic signal. A closing delay circuit that changes to an active state only when it remains active for a predetermined time longer than the charging time of the filter capacitor; and the circuit breaker is turned off when an output signal of the closing delay circuit becomes active. An auxiliary power supply device for a vehicle, characterized in that