JPH0789709B2 - Power failure detection device for AC electric vehicles - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an AC electric vehicle, and more particularly to a power failure detection device for detecting a power failure of electric power supplied from a bridge or the like.

[Technical background of the invention and its problems]

Power converters used in AC electric cars such as the current Shinkansen trains are composed of thyristors and diodes that do not have self-extinguishing ability. When these elements are used, it is possible to perform reverse conversion from DC power to AC power, that is, regenerative operation of the power converter, by devising the circuit configuration and the method of controlling the gate signal of the thyristor. However, such a converter has a problem that the AC power factor is poor.

By the way, in order to improve the power factor on the AC side, there has recently been active movement to adopt a power converter using a self-turn-off device such as a gate turn-off thyristor (GTO thyristor) in an AC electric vehicle. .

By the way, when using GTO etc. as this power converter, the following problems arise.

For trains, power outages due to the separation of pantographs and overhead lines and power outages when trains pass through substation switching divisions are inevitable, but if a power outage occurs during regenerative operation, the secondary side of the transformer and the primary A rectangular wave-like voltage containing a lot of high-frequency components on the side is generated. This voltage may cause very unfavorable results such as destruction of the device connected to the AC side or the transformer itself and deterioration of the life.

A voltage is generated in the transformer winding even during a power failure, because the power converter is a self-exciting converter that uses a self-extinguishing element, so regenerative operation is possible even if the AC power supply is disconnected, and the voltage value on the DC side This is because a rectangular wave voltage having a peak voltage value of is generated on the AC side of the power converter.

Due to such a problem, when a power converter using a self-extinguishing element capable of obtaining a high power factor is applied to an AC electric train, some measure against a power failure of the AC power supply is required.

In order not to generate unnecessary voltage on the secondary side of the transformer at the time of power failure, it suffices to detect the power failure and stop the operation of the converter.
Therefore, a device for detecting a power failure of the AC power supply has been required.

[Object of the Invention]

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a power failure detection device for an AC electric vehicle that enables sufficient protection of each device during a power failure of the AC power supply.

[Outline of Invention]

The present invention made in order to achieve the above-mentioned object, means for taking in the AC power for driving the AC electric vehicle through an overhead wire, and the AC current for determining the AC power taken in is below a predetermined value. And a first pulse signal output means for outputting a first pulse signal for each predetermined cycle of the AC voltage, and the cycle according to the first pulse signal output from the first pulse signal output means. Second pulse signal output means having a longer pulse width and outputting a second pulse signal as the power failure detection signal of the AC power, and the second pulse signal output from the second pulse signal output means And a controller for controlling the operation of the AC electric vehicle according to the above.

Example of Invention

Hereinafter, the present invention will be described in detail based on embodiments shown in the accompanying drawings.

An embodiment shown in FIGS. 1 to 3 is one in which the present invention is applied to a device for stopping a power converter using a self-extinguishing element or the like such as a GTO thyristor at the time of a power failure of power supplied to an AC electric vehicle. Is.

The configuration of the present embodiment has a pantograph 2 for contacting the overhead wire 1 with AC power supplied to an AC electric vehicle, a primary winding, and a ground 3.
The primary side circuit that receives power from the transformer, the transformer 4 that is connected to the power converter 7 on the secondary winding 6 side, and the primary winding 5 of the transformer 4 as the part corresponding to the power failure detection device 10. A current detector CT such as a measuring transformer that generates a signal I _P that indicates the flowing current value
If, when the absolute value of the signal I _P is compared with the signal I _P and a predetermined threshold value SL is equal to or greater than the threshold value SL, the logic signal is "1" and becomes the pulse signal P _C of the AC voltage 1st output every half cycle
Having a comparator 8 which is a pulse signal output means, a pulse width pulse signal P _C by inputting a pulse signal P _C to the clock input terminal CK is logic period defined from the time becomes "1" logic "1" A mono-multivibrator 9 that is a second pulse signal output means that outputs a pulse signal P _D that is a power failure detection signal, and an output signal of the mono-multivibrator 9 that is used as a power failure detection signal to control the operation of the power converter 7 are not shown. It consists of a control device.

Of these, the threshold value set in the comparator 8
SL is a reference value that determines whether signal I _P is I _P = 0 or I _P ≠ 0, but if threshold SL is set to SL ≈ 0, signal I _P
There is a possibility that the comparator 8 may malfunction due to the heavy noise. Therefore, as shown in FIG. 2 (a), the threshold value SL is the minimum current that flows in the primary winding 5 due to the AC voltage applied to the primary winding 5, that is, the current when the transformer 4 is unloaded. The current I _L is set to a detectable level.

The pulse width T ₂ of the pulse signal P _D is shown in FIGS. 2 (a) and 2 (b).
If the AC voltage is shorter than the half cycle T ₁ as shown in, that is, T ₁ > T ₂ , the pulse signal P _D
Is a logical “0”, so T ₁ <T ₂ is set so as to be longer than the half cycle T ₁ of the AC voltage.

The operation of the present embodiment configured as described above will be described below.

The AC electric vehicle in a normal state obtains an AC current from the overhead wire 1 via the pantograph 2 without a power failure, and supplies this AC current to the primary winding 5 side of the transformer 4. Then, the current value flowing through the primary winding is detected by the current detector CT,
For example, when the exciting current I _L is detected by the current detector CT when the transformer 4 is unloaded, the signal I _P is the threshold SL at every half cycle T ₁ of the AC voltage as shown in FIG. 2 (a). Over.
When the signal I _P exceeds the threshold value, the comparator 8 outputs the pulse signal P _C of logic "1" as shown in FIG. 2 (b). That is, the pulse signal P _C continues to be output every half cycle T _{1 of the} AC power as long as the AC power is supplied without a power failure. Then, the mono-multivibrator 9 which receives the signal of logic "1" for each half cycle T ₁ by the pulse signal P _C continuously outputs the pulse signal P _D of logic "1". Therefore, the power converter 7 can be continuously operated by the control device when the pulse signal P _D having the logic “1” is detected.

Next, the operation when the supplied AC power fails will be described.

When a power failure occurs in the supplied power, the signal I _P becomes “0” at the power failure occurrence time t ₁ as shown in FIG.
Since it becomes less than SL, the comparator 8 stops the output of the pulse signal P _C after the power failure occurrence time t _{1 as} shown in FIG. As a result, the mono-multivibrator is shown in FIG.
Pulse signal P _D after outputting a pulse signal P _D of the pulse width T ₂ from the time the last type the Parushi signal P _C as shown in
Stop the output of. Therefore, a logical "1" pulse signal
The control device of the power converter 7 in which P _D has stopped being input stops the driving operation of the power converter 7.

As described above, according to the present embodiment, in the AC electric vehicle equipped with the power converter using the self-extinguishing element such as the GTO thyristor, in the primary side and the secondary side of the transformer during the power failure of the supplied power. It is possible to eliminate various problems caused by a rectangular wave-shaped high voltage containing a large amount of high frequency components that occur. Further, by displaying the power failure on the driver's cab of the electric vehicle by using the power failure detection signal, it becomes possible for the driver to take special measures during the power failure.

〔The invention's effect〕

According to the present invention, by detecting the power failure of the power supplied to the AC electric vehicle by using the current, by stopping the operation of each device that causes a failure due to the power failure of the power, sufficient protection of each device Can be achieved.

[Brief description of drawings]

FIG. 1 is a configuration block diagram of an embodiment to which the present invention is applied,
2 to 3 are time charts for explaining the operation of the same embodiment. 1 ... overhead line, 4 ... transformer, 5 ... primary winding, 6 ... secondary winding, 7 ... power converter, 8 ... comparator, 9 ... mono-multivibrator 10 ... power failure detection device .

Claims (1)

[Claims] 1. A means for fetching AC power for driving an AC electric vehicle through an overhead wire, and a method for determining an AC voltage by determining that the AC current for determining the AC power taken is below a predetermined value. First pulse signal output means for outputting a first pulse signal at every predetermined cycle, and a pulse width longer than the cycle according to the first pulse signal output from the first pulse signal output means,
Second pulse signal output means for outputting a second pulse signal to be a power failure detection signal of the AC power; and an AC electric vehicle of the AC electric vehicle according to the second pulse signal output from the second pulse signal output means. A power failure detection device for an AC electric vehicle, comprising: a control device that controls driving.