JPS63265565A - Protector for thyristor rectifier - Google Patents

Abstract

PURPOSE:To improve safety and reliability, by a method wherein the actual period of AC voltage is detected by a voltage period detecting means and control operation is stopped when the abnormality of power source frequency is detected. CONSTITUTION:A phase control circuit 9 for a thyristor rectifier 4 is constituted of an amplifier 9a, comparing respective signals from a current detector 7 and a current commander 10, a synchronizing signal generating unit 9b, an integrator 9c, a comparator 9d and a gate ignition circuit 9e while the pulse from said igniting circuit 9e are distributed to respective thyristor gates. In this case, a transmitting circuit 12, capable of setting the range of predetermined set period, and a periodical signal generating period measuring circuit 13 are provided while the measuring circuit 13 is constituted of a voltage period detecting means 13a, a comparing means 13b and a phase control operation stopping means 13c. When an actual period is decided that it is in the range of the set period, a gate signal output stopping signal 14 is outputted to the gate igniting circuit 9e.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention provides a thyristor rectifier that rectifies an alternating current voltage by controlling the firing phase to vary its output voltage. This relates to a protection device that stops control.

[Prior Art] Fig. 2 is a circuit configuration diagram of a general electric vehicle in which a DC motor is driven by AC overhead wire input, and in the figure,
1 is an AC voltage overhead line, 2 is a pantograph, 3 is a transformer that lowers the overhead line voltage to a required voltage, 4 is a thyristor rectifier that controls the output DC voltage by the firing phase angle, 4a-
4d is a thyristor element constituting a thyristor rectifier;
5 is the armature coil of the DC motor, 6 is the field coil of the DC motor, 7 is the current detector, and 8 is the AC overhead line voltage that is connected to the transformer 3.
AC power signal dropped to a predetermined voltage by, 9 is a thyristor rectifier! 4, a phase control circuit that determines the gate firing timing; 10, a current command device that outputs a command to the phase control circuit 9; and 11, a thyristor rectifying bag T/lj! from the phase control circuit 9. This is the thyristor gate signal output to 4.

The phase control circuit 9 for the thyristor rectifier bag W14 is conventionally configured as shown in FIG. FIG. 3 is a configuration diagram of a conventional phase control circuit for a thyristor rectifier disclosed in, for example, Japanese Unexamined Patent Publication No. 59-185102.
In the figure, 9a is a comparison amplifier to which the current detection signal from the current detector 7 and the current command signal from the current command device 10 are input.

9b is a synchronization signal generator that receives the AC power signal 8 and generates a synchronization signal to perform firing phase control synchronized with the zero point of the voltage phase of the AC voltage; 9c is an integrator; 9d is a comparator; 9e is a gate This is an ignition circuit.

Next, the operation of the conventional phase control circuit 9 described above will be explained with reference to FIG. Incidentally, FIG. 4 shows a timing chart of output signals from each component of the phase control circuit 9 shown in FIG. 3.

The AC power signal 8 is input to a synchronizing signal generating section 9b, and a synchronizing signal synchronized with the zero point of the voltage phase of the AC power signal 8 is output from the synchronizing signal generating section 9b. Since this synchronization signal is input as a reset signal to the integrator 9C, the output waveform from the integrator 9C becomes a triangular waveform as shown in FIG.

On the other hand, the current detection signal from the current detector 7 and the current command device 1
The signal obtained by comparing and amplifying the current command signal from 0 by the comparator amplifier 9a and the output signal from the integrator 9C are output to the comparator 9.
d, and the comparison result is sent to the gate ignition circuit 9.
e.

Then, from this gate ignition circuit 9e, pulses distributed to each thyristor gate are outputted to the thyristor rectifier 4 as a final thyristor gate signal 11.

As a result, the firing phase of the thyristor rectifier bag @4 is controlled and the DC output voltage from the thyristor rectifier 4 is controlled so that the DC motor current becomes equal to the current command value from the current command device 10.

[Problems to be Solved by the Invention] Since the conventional phase control circuit for a thyristor rectifier is configured as described above, a signal synchronized with the AC power supply voltage is required, and a thyristor gate signal synchronized with this signal is required. 11 is applied to the thyristor rectifier 4. Therefore, even if the AC power frequency changes abnormally, the thyristor rectifier 4 will operate in synchronization with the abnormal input frequency, and especially when the input frequency decreases, it will cause the transformer 3 to become saturated, etc. In addition to having an adverse effect on equipment, there was a problem in that when the input frequency increased, it caused commutation loss in the thyristor.

Furthermore, there is a problem in that the thyristor rectifier bag [4] cannot be controlled when the AC voltage drops such that the synchronization signal cannot be reliably detected.

This invention was made to solve the above-mentioned problems, and when the frequency of the AC power supply changes abnormally or the frequency of the AC power supply cannot be detected, the abnormality is immediately detected and the control operation is stopped. Allows safety of thyristor rectifier.

The purpose of the present invention is to obtain a protection device for a thyristor rectifier with improved reliability.

[Means for Solving the Problems] A protection device for a thyristor rectifier according to the present invention includes a voltage cycle detection means for detecting cycle information of an AC voltage, and an actual cycle and a set cycle detected by the voltage cycle detection means. and a phase control operation stop means for stopping the ignition phase control operation when the comparison means determines that the actual cycle is not within the set cycle range. be.

[Function] In the protection device for a thyristor rectifier according to the present invention,
AC voltage cycle information (actual cycle) by voltage cycle detection means
is detected, the detected actual cycle and the set cycle range are compared by the comparing means, and if it is determined that the above actual cycle is not within the set cycle range, there is some problem such as an abnormal change in the AC power frequency or undetectability. It is assumed that an abnormality has occurred, and the ignition phase control operation is stopped by the phase control operation stopping means.

[Embodiment of the Invention] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. 1st
In the figure, 12 is a transmission circuit that can set a predetermined setting cycle range, 13 is a synchronizing signal generation cycle measuring circuit, and 14 is a thyristor gate signal output stop signal. 13a, comparison means 13b, and phase control operation stopping means 13c. The voltage cycle detecting means 13a detects the actual cycle of the AC voltage based on the synchronizing signal from the synchronizing signal generating section 9b, and the comparing means 13b detects the actual cycle from the voltage cycle detecting means 13a and from the transmitting circuit 12. This is to compare the set cycle range of . Further, the phase control operation stop means 13c outputs the thyristor gate signal output stop signal 14 to the gate ignition circuit 9e when the actual cycle is determined to be within the set cycle range as a result of the comparison in the comparison means 13b. be.

Incidentally, in FIG. 1, the same reference numerals as those already described indicate the same parts, and therefore, explanations thereof and their operations will be omitted.

Next, the operation of the protection device of this embodiment will be explained. In the voltage cycle detection means 13a, the synchronization signal generation section 9b
The actual period of the AC voltage is detected based on the synchronization signal synchronized with the zero point of the voltage phase in the AC voltage output from the
The detection result is input to the comparison means 13b.

The comparing means 13b receives the clock signal from the transmitting circuit 12 as a set period range, and the voltage period detecting means 1
It is determined whether the actual cycle from 3a is within the set cycle range.

For example, if the rated frequency of the AC power supply is 50Hz,
During normal operation, the synchronization signal generator 9b outputs a synchronization signal that detects the zero point of the voltage phase every 1Qmsec. Here, the allowable frequency deviation for one circuit operation is 50
In the case of Hz±10%.

If the period of the synchronization signal is within the range of 9 to 11 m5ec, it is considered normal operation, and the synchronization signal is input to the integrator 9C,
Conventional phase control as shown in FIG. 4 is performed.

On the other hand, if the actual period of the synchronization signal exceeds 11m5ec,
Or if it becomes smaller than 9 m5ec.

The comparison means 13b determines that there is an abnormality in the power supply frequency (an abnormal change in the AC power supply frequency or some kind of abnormality such as undetectability), and the phase control operation stop means 13c receives the determination result from the comparison means 13b and stops the thyristor gate signal output. The signal is output to the gate firing circuit 9e, and the firing phase control of the thyristor rectifier 4 by the phase control circuit 9 is stopped.

As described above, according to this embodiment, by constantly measuring the generation cycle of the synchronization signal, an abnormality in the power supply frequency is quickly detected and the control operation is stopped. The ignition phase control of the thyristor rectifying bag 5!4 is carried out by the one-phase control circuit 9 only when is occurring at a predetermined period, thereby ensuring the safety of the thyristor rectifying device.
Reliability is greatly improved.

[Effects of the Invention] As described above, according to the present invention, when the voltage cycle detection means detects the actual cycle of the AC voltage and the comparison means detects an abnormality in the power frequency, the phase control operation means promptly performs the control operation. Since the configuration is configured so that the AC voltage stops at
The firing phase control of the thyristor rectifier is carried out, which has the effect of greatly improving the safety and reliability of the thyristor rectifier.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of a protection device for a thyristor rectifier according to an embodiment of the present invention, Fig. 2 is a circuit block diagram of a general electric vehicle that drives a DC motor by AC overhead line input, and Fig. 3
The figure is a block diagram of a conventional phase control circuit for a thyristor rectifier, and FIG. 4 is a timing chart for explaining the operation of the phase control circuit. In the figure, 4. - thyristor rectifier, 13a - voltage cycle detection means, 13b - comparison means, 13c - phase control operation stop means. In addition, in the figures, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims] A thyristor rectifier that rectifies the AC voltage to vary its output voltage by controlling the firing phase synchronized with the zero point of the voltage phase of the AC voltage, a voltage cycle detection means for detecting period information of the AC voltage; Comparison means for comparing the actual cycle detected by the voltage cycle detection means with a set cycle range, and when the comparison means determines that the actual cycle is not within the set cycle range, 1. A protection device for a thyristor rectifier, comprising phase control operation stopping means for stopping arc phase control operation.