JP3245716B2 - Current interrupter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a current interrupting device using a vacuum valve for protecting a power circuit of an electric vehicle.

[0002]

2. Description of the Related Art An example of a power supply circuit of a general electric car is shown in FIG.
Shown in 2. Description of the Related Art Conventionally, in an electric car, an overhead line 1, a pantograph 2, a main circuit switch (LS) 3 for normally turning on and off a circuit and a high-speed circuit breaker (HB ) Are inserted in series on the power supply side of the control device 5.
The high-speed circuit breaker 4 normally detects a current flowing from a power supply as a main circuit current I. A current detector is provided,
When the main circuit current I becomes excessive, it has a function of automatically opening a main contact and interrupting the current. The details of the function are as follows. The main circuit current I is passed through the coil, the plunger is operated by the electromagnetic force generated by this current, and the main contact is opened (tripped) mechanically. It is a mechanism to shut off.

Recently, in pursuit of arcless, ultra-high speed, etc. in place of the above-mentioned aerial type high-speed circuit breaker, a breaking device using a vacuum valve in a current breaking circuit has been developed.

The shut-off operation of the above device will be described with reference to FIG.

[0005] A vacuum valve 11, a circuit in which a commutation switch 12, a commutation reactor 15, and a commutation capacitor 13 are connected in series, and a nonlinear resistor 14 are connected in parallel with the vacuum valve. The commutation capacitor 13 is charged to a polarity shown in FIG. 6 by a charging device (not shown).

At this time, when a shutoff command is given from the outside, the vacuum valve 11 opens, and then the commutation switch 12 is turned on. Then, the vacuum valve 11 and the commutation switch 12
A resonance current flows through the series resonance circuit composed of the commutation reactor 15 and the commutation capacitor 13 due to the charge stored in the commutation capacitor 13. The constant of the resonance circuit is selected so that the maximum value of this current is larger than the maximum value of the main circuit current I.

After the opening of the vacuum valve 11, the main circuit current I continues to flow as an arc in the vacuum gap in the vacuum valve 11. At this time, the resonance current is an alternating current in which the current flowing direction changes alternately. The main circuit current I is a direct current in which the current flows in one direction, the directions of both currents are opposite to each other, and there is a moment when the current in the vacuum valve becomes zero. The instantaneous vacuum valve 11 recovers the pressure resistance, and a voltage is generated at both ends of the valve. This voltage is substantially equal to the voltage stored in the commutation capacitor 13 at that time. Then, the main circuit current I continues to flow through the commutation capacitor 13. As the main circuit current I continues to flow through the commutation capacitor 13, the commutation capacitor 13 is charged in the opposite direction, and the voltage of the commutation capacitor 13 reverses and is further pushed up.

When this voltage becomes higher than a certain level, a current starts to flow through the nonlinear resistor 14. Since this voltage is set higher than the power supply voltage, the main circuit current I attenuates and eventually becomes zero.

FIG. 7 shows the above-mentioned operation over time. In FIG. 7, t1 is the commutation switch 12
Is inputted, t2 is the timing when the voltage of the vacuum valve 11 becomes zero, and t3 is the nonlinear resistance 14.
The timing at which the current starts to flow through the main circuit current I4
Indicates the timing at which the signal has completely attenuated. In addition, vacuum valve 1
1 has already been opened before t1. In FIG. 7, Vi is a voltage applied to both ends of the vacuum valve 11 immediately after the vacuum valve 11 recovers the breakdown voltage, and is substantially equal to the voltage of the commutation capacitor 13 at this time. Vn is a voltage at which a current starts flowing through the nonlinear resistor 14, and Ve is a power supply voltage.

[0010]

In a vacuum valve, the arc spreads very quickly, the withstand voltage is restored at the moment when the current becomes zero, and the current is cut off. However, if the rate of change of the current is too large, Even if the current becomes zero, re-arcing may occur, and the current may flow again in the opposite direction. FIG. 8 shows a waveform at the time of failure of the cutoff. Originally, the withstand voltage of the valve was recovered from the moment the current in the vacuum valve became zero, and the one in which the current in the vacuum valve should be kept zero after that was changed to DC It flows with a waveform in which the resonance current Ip is superimposed on the main circuit current I. In order to reduce the size of the device, smaller values of the commutation capacitors and commutation reactors are suitable, but if the peak value of the resonance current Ip is kept constant and each constant is selected to be small, the resonance current The frequency of Ip increases. As a result, the current change rate at the time when the current of the vacuum valve becomes zero becomes large, and there is a possibility that the cutoff cannot be performed due to re-arcing.

An object of the present invention is to avoid the above-mentioned disadvantages and reduce the size of the current interrupting device.

[0012]

An object of the present invention is to provide a first series body in which a capacitor, an opening / closing means, and a floating inductance of a reactor or a wiring are connected in series, and a charging means for charging the capacitor. A vacuum valve that cuts off direct current, an element that is connected in parallel to the vacuum valve and consumes energy stored in the stray inductance of the wiring, and a saturable parallel element that connects the element and the vacuum valve in parallel. This is achieved by a second series body in which the reactors are connected in series, and the second series body and the first series body are connected in parallel.

The object is to provide a first series body in which a capacitor, switching means, and a stray inductance of a reactor or wiring are connected in series, charging means for charging the capacitor, a vacuum valve for shutting off direct current, An element that is connected in parallel to the valve and consumes energy stored in the stray inductance of the wiring, and a second series in which a saturable reactor is connected in series to a parallel body in which the element and the vacuum valve are connected in parallel. The body, the second series body and the first series body are connected in parallel, the resonance frequency of a closed circuit including the vacuum valve, the saturable reactor, the switching means and the capacitor is set to 2 KHz or more, and the commutation current is reduced. 5000A
And the commutation inductance included in the closed circuit is 1
Achieved by setting it to not less than μH.

The object of the present invention is to provide a first series body in which a stray inductance of a capacitor, switching means and a reactor or wiring is connected in series, charging means for charging the capacitor, a vacuum valve for shutting off direct current, An element that consumes energy stored in the stray inductance of the capacitive element and the wiring connected in parallel to the valve;
A second series body in which a saturable reactor is connected in series to a parallel body in which the element and the capacitive element and the vacuum valve are connected in parallel; and the second series body and the first series body are connected in parallel. It is achieved by doing.

The object is to provide a first series body in which a capacitor, switching means and a stray inductance of a reactor or wiring are connected in series, a charging means for charging the capacitor, a vacuum valve for shutting off direct current, An element that consumes energy stored in the stray inductance of the capacitive element and the wiring connected in parallel to the valve;
A second series body in which a saturable reactor is connected in series to a parallel body in which the element and the capacitive element and the vacuum valve are connected in parallel; and the second series body and the first series body are connected in parallel. An element that consumes energy stored in the floating inductance of the vacuum valve and the wiring, or a vacuum valve and the capacitive element, based on a loop length of a closed circuit including the vacuum valve, the saturable reactor, the opening / closing means, and the capacitor. This is achieved by shortening the loop length of the closed circuit including

[0016] The above object is achieved by connecting a first series body in which a capacitor and switching means are connected in series, a charging means for charging the capacitor, a vacuum valve for cutting off direct current, and a parallel connection to the vacuum valve. and a capacitive element, a second series body and the series of second first series body of connecting the saturable reactor in parallel body connected to the vacuum valve and said capacitive element in parallel to the series Are connected in parallel.

An object of the present invention is to provide a current interrupting device for an electric vehicle, which interrupts a DC current supplied from an overhead line to a main motor,
A first series body in which a capacitor, an opening / closing means, and a stray inductance of a reactor or a wiring are connected in series, a charging means for charging the capacitor, a vacuum valve for shutting off direct current, and a parallel to the vacuum valve An element consuming the energy stored in the stray inductance of the wiring, and a second series body in which a saturable reactor is connected in series to a parallel body in which the element and the vacuum valve are connected in parallel; This is achieved by connecting the second series body and the first series body in parallel.

An object of the present invention is to provide a current interrupting device for an electric vehicle for interrupting a DC current supplied from a wire to a main motor,
A first series body in which a capacitor, an opening / closing means and a stray inductance of a reactor or a wiring are connected in series, a charging means for charging the capacitor, a vacuum valve for cutting off direct current, and a parallel connection to the vacuum valve A capacitive element and an element that consumes energy stored in the stray inductance of the wiring, and a second element in which a saturable reactor is connected in series to a parallel body in which the element and the capacitive element and the vacuum valve are connected in parallel. A series body, the second series body and the first series body are connected in parallel, and the vacuum valve;
This is achieved by shortening the loop length of the closed circuit including the element that consumes the energy stored in the floating inductance of the vacuum valve and the wiring, from the loop length of the closed circuit including the saturable reactor, the opening / closing means, and the capacitor. You.

[0019]

According to the present invention, a zero point of a current is created in a vacuum valve by flowing a current in a direction opposite to a main circuit current by a resonance circuit including a capacitor, and each constant of the resonance circuit is reduced to reduce the frequency of the resonance current. With a high current peak value, a saturable reactor, whose inductance increases as the current decreases only near the zero point of the current, is inserted in series with the vacuum valve in series with the vacuum valve. By reducing the current change rate near the zero point, when the current becomes zero, the pressure resistance of the vacuum valve recovers, and the current is cut off at a high speed. In this way, the resonance circuit can be configured with small constants, so that the current interrupting device is downsized.

[0020]

An embodiment of the present invention will be described with reference to the drawings.

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

In an electric car, an overhead line, a pantograph,
A main circuit switch (LS) for turning on and off the circuit during normal times and a current cutoff device called a high-speed circuit breaker (HB) are connected in series with the power supply side of the control device to cut off the current that increases rapidly in the event of an accident in a short time. Has been inserted. In the current interrupting device of the present embodiment, one of a series body in which a vacuum valve 11 for shutting off DC current and a saturable reactor 16 are connected in series is connected to the main circuit switch (LS) side, and the other of the series body is connected to the other. A control device for controlling the main motor is connected. A series body including the commutation switch 12 and the commutation reactor 15 or the stray inductance of the wiring and the commutation capacitor 13 is connected in parallel to the series body including the vacuum valve 11 and the saturable reactor 16. The stray inductance of the wiring is 1 μH or more even if the wiring is made as short as possible. A charging device (not shown) for charging is connected to the commutation capacitor 13. A non-linear resistor 14 that consumes energy stored in the floating inductance of the wiring is connected in parallel with the vacuum valve 11. The floating inductance of the closed circuit formed by the vacuum valve 11 and the non-linear resistor 14 includes a vacuum valve 11, a saturable reactor 16, a commutation switch 12, a commutation reactor 15, and a commutation capacitor 13.
And smaller than the stray inductance of the closed circuit composed of
Therefore, current flows more easily to the non-linear resistor 14 having a smaller inductance than the commutation circuit having a larger inductance.

FIG. 2 is a chart showing the characteristics of the saturable reactor 16. When the current value is small, the saturable reactor 16 has a very large inductance value, and when the current value exceeds a certain level, the inductance value rapidly decreases.

Next, the operation of this embodiment will be described.

FIG. 3 shows the waveform of each element when the current is cut off. Basically, it is the same as FIG. 6, but at the timing t2, that is, immediately before the current zero point of the vacuum valve, the current change rate is extremely small. The commutation capacitor 13 is charged to the polarity shown in FIG. 1 by a charging device (not shown). When a shutoff command is given from the outside, the vacuum valve 11 opens, and after the opening, the main circuit current I continues to flow as an arc in the vacuum gap in the vacuum valve 11. Thereafter, at t1, the commutation switch 12 is turned on. Then, a resonance current flows through the series resonance circuit constituted by the vacuum valve 11, the commutation switch 12, the commutation reactor 15, and the commutation capacitor 13, due to the charge stored in the commutation capacitor 13. Conventionally, the upper limit of the resonance frequency was 1 KHz, because a commutation reactor was used as the inductance of the series resonance circuit. In the present invention, by replacing the commutation reactor with the stray inductance of the wiring, the inductance is significantly reduced, and the resonance frequency can be increased to 2 KHz or more. The maximum value of this current is preferably 1.2 times or more the maximum value of the main circuit current I, and the main circuit current I is determined by the output of the main motor and the power supply voltage of the electric vehicle serving as a load. Main motor output of electric vehicle 500-6000Kw and power supply voltage 600-3
Considering about 000 V, the value of the resonance current, that is, the commutation current, is desirably 5000 A or more. Then, the constant of the resonance circuit is selected so as to obtain such a value. The resonance current is an alternating current in which the direction in which the current flows alternately changes, the main circuit current I is a direct current in which the current flows in one direction, the directions of both currents are opposite to each other, and the current in the vacuum valve is zero. Moment t2 exists. Immediately before the zero point, the current flowing through the vacuum valve 11 is cut off because the current change rate is extremely small. At this moment, the vacuum valve 11 recovers its pressure resistance and generates a voltage Vi across the valve. This voltage is substantially equal to the voltage stored in the commutation capacitor 13 at that time. And the main circuit current I
Continue flowing through the commutation condenser 13. As the main circuit current I continues to flow through the commutation capacitor 13, the commutation capacitor 13 is charged in the opposite direction, and the voltage of the commutation capacitor 13 reverses and further rises. When the voltage Vn becomes higher than a certain level, a current in the direction opposite to the main circuit current I starts to flow through the nonlinear resistor 14 at t3. Since this voltage Vn is set higher than the power supply voltage Ve, the main circuit current I attenuates and eventually becomes zero at t4. In this way, the main circuit current I is cut off at a high speed.

According to the present embodiment, the current change rate near the current zero point can be reduced without changing the constant values of the resonance circuit, and the withstand pressure of the vacuum valve can be reliably recovered.

Next, another embodiment will be described.

FIG. 4 is a circuit diagram showing a configuration of another embodiment.

In the above embodiment, the saturable reactor 16 is inserted in order to suppress the current change rate near the current zero point of the vacuum valve 11. However, in addition to the current change rate, factors that hinder the recovery of the pressure resistance of the vacuum valve 11 include: The voltage change rate in the process of recovering the breakdown voltage also becomes a problem. That is, if the voltage change rate is large, a dielectric breakdown occurs in the process of recovering the breakdown voltage, and a re-arcing occurs and a current flows again. If a capacitor 17 is connected in parallel between the electrodes of the vacuum valve 11 to prevent this phenomenon, the voltage rise between the electrodes of the vacuum valve slows down due to charging of the capacitor 17, and the voltage between the electrodes of the vacuum valve shown in FIG. You can slow down abrupt changes. The capacity of the capacitor 17 may be larger than the capacity of the vacuum valve 11 when the electrode is opened, but the limit is set in a range that can be mounted on the electric vehicle. The stray inductance of the closed circuit formed by the vacuum valve 11 and the capacitor 17 is larger than the stray inductance of the closed circuit formed by the vacuum valve 11, the saturable reactor 16, the commutation switch 12, the commutation reactor 15, and the commutation capacitor 13. small. Therefore, current flows more easily to the capacitor 17 having a smaller inductance than to the commutation circuit having a larger inductance.

According to the present embodiment, a capacitor can be connected in parallel between the vacuum valve electrodes to reduce the sudden change in the voltage between the vacuum valve electrodes, thereby reducing the possibility of re-ignition of the vacuum valve.

As described above, the current interrupting device according to the present embodiment reliably shuts off the current with the resonance circuit having a small constant value, so that it is possible to reduce the size of the current interrupting device. The degree of freedom in layout design increases.

[0032]

According to the present invention, a saturable reactor is connected in series to a vacuum valve in a resonance circuit having a small constant value to reduce the current change rate near the current zero point, or a capacitor is connected in parallel to the vacuum valve. By connecting, the voltage change rate near the current zero point can be reduced to ensure the withstand pressure recovery of the vacuum valve, and the current interrupting device can be downsized.

[Brief description of the drawings]

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

FIG. 2 is a chart showing characteristics of a saturable reactor.

FIG. 3 is a waveform diagram of each element when current is cut off in the circuit according to the embodiment of the present invention.

FIG. 4 is a circuit diagram showing a configuration of another embodiment of the present invention.

FIG. 5 is a power supply system diagram of an electric vehicle provided with a conventional current cutoff circuit.

FIG. 6 is a circuit diagram of a current interrupting device using a conventional vacuum valve.

FIG. 7 is a waveform diagram of each element when current is cut off in a conventional circuit.

FIG. 8 is a waveform diagram of each element when current interruption has failed in a conventional circuit.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Overhead wire 2 Pantograph 3 Main circuit switch 4 High-speed circuit breaker 5 Controller 11 Vacuum valve 12 Commutation switch 13 Commutation capacitor 14 Nonlinear resistance 15 Commutation reactor 11 Vacuum valve 12 Commutation switch 13 Commutation capacitor 14 Nonlinear resistance 15 Flow reactor 16 Saturable reactor 17 Capacitor

────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Taro Uchii 1070 Ma, Katsuta-shi, Ibaraki Pref. Mito Plant, Hitachi, Ltd. (56) References JP-A-3-67429 (JP, A) JP-A-4 JP-A-54-149873 (JP, A) JP-A-58-133235 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01H 33/66 H01H 33/59

Claims (8)

(57) [Claims] A first capacitor connected in series with a stray inductance of a capacitor, an opening / closing means and a reactor or a wiring;
And a charging means for charging the capacitor, a vacuum valve for shutting off direct current, an element connected in parallel to the vacuum valve and consuming energy stored in the floating inductance of the wiring, and A second series body in which a saturable reactor is connected in series to a parallel body in which the vacuum valves are connected in parallel, and the second series body and the first series body are connected in parallel. Current interrupt device. 2. A first circuit comprising a capacitor, an opening / closing means, and a stray inductance of a reactor or a wiring connected in series.
And a charging means for charging the capacitor, a vacuum valve for shutting off direct current, an element connected in parallel to the vacuum valve and consuming energy stored in the floating inductance of the wiring, and A second series body in which a saturable reactor is connected in series to a parallel body in which the vacuum valves are connected in parallel; and a second series body and the first series body in which the second series body and the first series body are connected in parallel. A current interrupting device, wherein a resonance frequency of a closed circuit including a saturation reactor, a switching means, and a capacitor is 2 KHz or more, a commutation current is 5000 A or more, and a commutation inductance included in the closed circuit is 1 μH or more. 3. A first capacitor connected in series with a stray inductance of a capacitor, switching means and a reactor or a wiring.
, A charging means for charging the capacitor, a vacuum valve for blocking direct current, a capacitive element connected in parallel to the vacuum valve, and an element consuming energy stored in the floating inductance of the wiring. A second series body in which a saturable reactor is connected in series to a parallel body in which the element and the capacitive element and the vacuum valve are connected in parallel, and the second series body and the first series body are connected in parallel. A current interruption device, wherein the current interruption device is connected to the current interruption device. 4. A first capacitor connected in series with a stray inductance of a capacitor, switching means and a reactor or wiring.
, A charging means for charging the capacitor, a vacuum valve for blocking direct current, a capacitive element connected in parallel to the vacuum valve, and an element consuming energy stored in the floating inductance of the wiring. A second series body in which a saturable reactor is connected in series to a parallel body in which the element and the capacitive element and the vacuum valve are connected in parallel, and the second series body and the first series body are connected in parallel. And a closed circuit loop including an element that consumes energy stored in the floating inductance of the vacuum valve and the wiring, based on a loop length of the closed circuit including the vacuum valve, the saturable reactor, the switching means, and the capacitor. A current cutoff device having a reduced length. 5. A first device in which a stray inductance of a capacitor, a switching means and a reactor or a wiring is connected in series.
, A charging means for charging the capacitor, a vacuum valve for blocking direct current, a capacitive element connected in parallel to the vacuum valve, and an element consuming energy stored in the floating inductance of the wiring. A second series body in which a saturable reactor is connected in series to a parallel body in which the element and the capacitive element and the vacuum valve are connected in parallel, and the second series body and the first series body are connected in parallel. Wherein the loop length of the closed circuit including the vacuum valve and the capacitive element is shorter than the loop length of the closed circuit including the vacuum valve, the saturable reactor, the switching means, and the capacitor. apparatus. 6. A first series body in which a capacitor and an opening / closing means are connected in series, a charging means for charging the capacitor, a vacuum valve for blocking direct current, and a capacitive element connected in parallel to the vacuum valve. and element, the capacitive and second series body element and the vacuum valve was connected to saturable reactor in parallel body connected in parallel with the series, the series body and the first second
A current interrupting device, wherein a series body of the above is connected in parallel. 7. A current interrupting device for an electric vehicle for interrupting a DC current supplied from an overhead wire to a main motor, wherein a first inductor is connected in series with a capacitor, an opening / closing means, and a floating inductance of a reactor or wiring. And a charging means for charging the capacitor, a vacuum valve for shutting off direct current, an element connected in parallel to the vacuum valve and consuming energy stored in the floating inductance of the wiring, and A second series body in which a saturable reactor is connected in series to a parallel body in which the vacuum valves are connected in parallel, and the second series body and the first series body are connected in parallel. Current interrupter for electric vehicles. 8. A current interrupting device for an electric vehicle for interrupting a DC current supplied from an overhead wire to a main motor, comprising: a first series body in which a capacitor, an opening / closing means, and a stray inductance of a reactor or a wiring are connected in series; Charging means for charging the capacitor, a vacuum valve for shutting off direct current, a capacitive element connected in parallel to the vacuum valve and an element consuming energy stored in the floating inductance of the wiring; and A second series body in which a saturable reactor is connected in series to a parallel body in which the capacitive element and the vacuum valve are connected in parallel, and the second series body and the first series body are connected in parallel, Due to the loop length of the closed circuit including the vacuum valve, the saturable reactor, the opening / closing means and the capacitor, the voltage is stored in the floating inductance of the vacuum valve and the wiring. A current cut-off device for an electric vehicle, wherein a loop length of a closed circuit including an element consuming energy is reduced.