JP2712178B2 - Optical thyristor gate control device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gate control circuit of a thyristor of a rectifier constituted by an optical thyristor, and particularly to a gate control device of an optical thyristor. B. Summary of the Invention The present invention relates to a rectifier in which a plurality of optical thyristors are connected in parallel to form a switching arm, and the plurality of optical thyristors of the switching arm are respectively made conductive and non-conductive. When the load current is small without selectively or uniformly applying a gate signal to the plurality of optical thyristors, a gate signal having a different phase is sequentially supplied to each of the plurality of optical thyristors, and when the load current increases. Only by providing the same phase gate signal to all of the plurality of optical thyristors, it is possible to obtain a gate control device having a longer life of the optical thyristor. C. Prior Art Optical thyristors are widely applied to power converters such as rectifiers and inverters, and other electrical devices. In particular, in a power converter, a plurality of optical thyristors are connected in parallel to cope with a required load current in view of the capacity of the optical thyristor. A light emitting circuit is required to control these optical thyristors, and a light emitting diode is generally used as a light emitting element of the light emitting circuit. In order to control conduction of a plurality of optical thyristors connected in parallel, a plurality of corresponding light emitting elements are required, and during operation of the apparatus, the light emitting elements are always turned on to supply a gate signal. D. Problems to be Solved by the Invention A light emitting element such as a light emitting diode has a shorter life than an optical thyristor, and if the light emitting element is constantly turned on during operation of the apparatus, it causes a failure of the apparatus and increases reliability. SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to provide a highly reliable optical thyristor gate control device by adjusting the operation load of a light emitting element according to the magnitude of a load current. That is. E. Means for Solving the Problems A switching arm formed by connecting a plurality of optical thyristors in parallel is bridge-connected to form a rectifier, and the plurality of optical thyristors of the switching arm of the rectifier are turned on and off, respectively. A gate signal generating circuit for generating a gate signal having a phase corresponding to the current flowing through the switching arm; and the plurality of light sources connected in parallel based on a signal synchronized with the frequency of the current. A ring counter for generating a plurality of pulse train signals having a number corresponding to the number of thyristors, a simultaneous conduction signal generated on condition that a current flowing through the switching arm has exceeded a set value, and one of the plurality of pulse train signals; One OR condition and a number corresponding to the number of the parallel optical thyristors outputting a signal based on the common signal. A plurality of OR gates, and a plurality of OR gates each corresponding to the number of the parallel optical thyristors that output a light emission control signal on the basis of each output signal of the plurality of OR gates and a gate signal generated from the gate signal generation circuit under an AND condition. A light emitting control circuit comprising an AND gate and a light emitting circuit having a light emitting element which operates in response to the light emitting control signal and supplies an optical gate signal to the plurality of optical thyristors. F. Action In an optical thyristor switching circuit in which the element configuration is used in parallel, without constantly giving a gate signal to the light emitting element,
Usually, only a certain time is given sequentially. When the load current increases, the current is detected by a current detector. When the current exceeds a set value, a gate signal is applied to all the light emitting elements to turn on all the elements. When the load current decreases, the switching is performed again so that the gate signal is sequentially applied to each element. G. Embodiment FIGS. 1 and 2 show an optical thyristor gate control device according to an embodiment of the present invention. FIG. 1 is an overall configuration diagram, and FIG. 2 is a configuration diagram of a main part. In FIG. 1, A is a gate signal generation circuit that receives a current detection signal Id of the current transformer 1 and a voltage detection signal Vd of the transformer 2 provided on the AC input side of the rectifier E, and B is the gate signal generation circuit A. a current detection signal Id of the gate signals S ₁ and a current transformer 1 which is a light emitting control circuit to input. C is a light-emitting circuit, and inputs the light emission control signal S ₂ of the light emission control circuit B, and generates an optical gate signal S ₃ operates in response to the light emitting control signal S _2. Each switching arm D in the bridge circuit of the rectifier E
In the plurality of optical thyristor 3a, 3b, 3c are connected in parallel, these optical thyristor 3a~3c is conducting non-conducting by an optical gate signal S ₃ supplied through the light guide 4 from the light emitting circuit C. Current transformer 1, Transformer 2. Gate signal generation circuit A, Light emission control circuit
B, the light emitting circuit C and the switching arm D form a major loop, and the current transformer 1, the light emitting control circuit B, the light emitting circuit C and the switching arm D form a minor loop. Gate signal generating circuit A input voltage of the rectifier E, generates a gate signals S ₁ in accordance with the current, the light emission control circuit B trigger signals and current transformer synchronized from the gate signal generating circuit A gate signals S _1, the current frequency the original logical operation of the current detection signal Id from the vessel 1 and outputs a light emission control signal S _2. Emitting circuit C operates in response to the logic signal from the light emission control circuit B, and inputs the optical gate signals S ₃ through the light guide 4 to the optical thyristor 3a~3c switching arm D. FIG. 2 shows details of the gate signal generation circuit A, the light emission control circuit B, and the light emission circuit C. In FIG.
5 is a voltage setting device for setting the output voltage of the rectifier E;
Reference numeral 6 denotes a first matching circuit which receives a set voltage signal of the voltage setting device 5 and a voltage detection signal Vd as inputs, and inputs a deviation voltage signal thereof to a voltage amplifier 7. Reference numeral 8 denotes a second matching circuit which receives the output signal of the voltage amplifier 7 and the current detection signal Id as inputs and outputs a comparison signal to the current amplifier 9. here,
The reason why the second matching circuit 8 is provided is that the device is controlled at a constant voltage. However, in order to prevent the load from suddenly changing due to the circuit conditions and the operation of the device from becoming unstable, a minor loop control of the current is performed. This is for stabilization. An integrator 10 integrates the output current of the current amplifier 9.
Reference numeral 11 denotes a phase control circuit which generates a phase control signal according to the integration signal of the integrator 10. The reason why the integrator 10 is provided here is to prevent the phase control circuit 11 from malfunctioning by removing the noise component of the signal because the phase control circuit 11 is easily affected by noise. The output of the phase control circuit 11 outputs signals corresponding to the U, V, W and X, Y, Z phases when the AC input of the rectifier has three phases. For example, only the U phase is shown. 12a to 12c are gate pulse signal generation circuits. Voltage setting device 5, first matching circuit 6, voltage amplifier 7,
A gate signal generation circuit A is configured by the second matching circuit 8, the current amplifier 9, the integrator 10, the phase control circuit 11, and the gate pulse signal generation circuits 12a to 12c. Reference numeral 13 denotes a clock signal generation circuit that generates a clock signal in synchronization with the power supply frequency. Reference numeral 14 denotes a ring counter which generates a plurality of signals having different phases according to a clock signal. 15a to 15c are control signal generation circuits, and the ring counter 14
Generates a control pulse signal in accordance with the output of. This signal is generated in synchronization with the rise of the power supply frequency waveform (positive than zero) and has a waveform width of 360 °. 16 is a rectifier circuit that rectifies the current detection signal Id as an input, 17 is a current setting device,
Reference numeral 18 denotes a third matching circuit, and reference numeral 19 denotes a comparator, which generates an output when a deviation signal from the matching circuit 18 exceeds a certain level. This constant level is set to a value corresponding to the current withstand capability of one optical thyristor. Therefore,
When the current detection signal Id corresponding to the load current increases and exceeds the current withstand capability of one optical thyristor, a signal for turning on the light emitting diodes 25a to 25c of all the arms is generated. 20a
~ 20c is an OR gate, 21a ~ 21c is an AND gate, 22a ~ 22c
Is a buffer circuit. These clock signal generation circuits
13, ring counter 14, control signal generating circuits 15a to 15c, rectifying circuit 16, third matching circuit 18, comparator 19, or gate 2
0a to 20c, AND gates 21a to 21c, and buffer circuit 22a
22c constitute a light emission control circuit B. Light emitting circuit C is a transistor that is a switching element
23a to 23c, light emitting diodes 25a to 25c as light emitting elements and resistors 24a to 24c, each light emitting diode 25
An optical gate signal is supplied from a to 25c to the optical thyristors 3a to 3c of the switching arm D through the light guides 4a to 4c. In the optical thyristor gate control device having the above configuration,
The signal waveform of the main part will be described with reference to FIG. Figure 3 is when the load current is small in the normal, the gate pulse signal output signal S _1a to S _1c of the signal waveform generation circuit 12 a to 12 c, the control signal generating circuit output signal waveform and the AND gate 21a of 15a~15c 21 shows output signal waveforms of 21c. The input voltage of the rectifier E is detected by the transformer 2 and the voltage detection signal Vd is applied to the first matching circuit 6 of the gate signal generation circuit A.
Is input to The first matching circuit 6 outputs a voltage deviation signal between the set voltage of the voltage setting device 5 and the voltage detection signal Vd so as to keep the output voltage of the rectifier E constant. After the voltage deviation signal is amplified by the voltage amplifier 7, it is input to the second matching circuit 8, and a comparison signal with the current detection signal Id is obtained. The comparison signal is amplified by the current amplifier 9 and then integrated by the integrator 10. The phase control circuit 11 outputs the output signal of the integrator 10, that is, the second matching circuit 8
And a phase control signal for controlling the firing phase of the optical thyristor of the rectifier is generated and output to the gate pulse signal generation circuits 12a to 12c. Gate pulse signal generation circuit 12a~12c generates the gate signals S _1a to S _1c shown in FIG. 3 on the basis of this signal. In the light emission control circuit B, the ring counter 14 is a clock signal generation circuit for generating a signal synchronized with the power supply frequency.
Based on the clock signal from 13, three sets of pulse train signals having different phases sequentially sent to the parallel optical thyristors are generated. These pulse train signals are input to the control signal generation circuits 15a to 15c, respectively. Control signal generation circuits 15a to 15c
Generates a control pulse signal having a different phase according to the pulse signal from the ring counter 14. The current detection signal Id from the current transformer 1 is input to the rectifier 16. The third matching circuit 18 compares the rectified output current of the rectifier 16 with the current setting signal of the current setting unit 17 and outputs a current deviation signal to the comparator 19. Normally, the comparator 19 does not generate a signal because the current detection signal Id is smaller than the current setting signal. Therefore, the signals input to the OR gates 20a to 20c are regulated by the control signal generating circuits 15a to 15c as shown in FIG.
20a receives a control pulse signal of the control signal generation circuit 15a as an input, an OR gate 20b receives a pulse signal of the control signal generation circuit 15b as an input, and an OR gate 20c inputs a pulse signal of the control signal generation circuit 15c. The AND gate 21a receives the output signal of the gate pulse signal generation circuit 12a and the output signal of the OR gate 20a, and the AND gate 21b receives the output signal of the gate pulse signal generation circuit 12b and the output signal of the OR gate 20b, and the AND gate 21c. Input the output signal of the gate pulse generation circuit 12c and the output signal of the OR gate 20c. AND Gate 21a-21
The output signal of c are respectively input as the emission control signal S _2a to S _2c to the light emitting circuit C via the buffer circuit 22 a to 22 c. The current setting value of the current setting device 17 is set to be equal to or less than the current withstand capability of each of the optical thyristors 3a to 3c.Here, since the load current is small and the output of the comparator 19 is `` none, '' the OR gates 20a to 20c Each input is a gate pulse signal generation circuit
Only pulse signals from 15a to 15c are provided. Therefore, the output signals of the AND gates 21a to 21c are the signals shown in FIG.
gate signal S _1a to S _1c becomes and synchronized with the pulse signal of the gate pulse signal generation circuit 12a~12c as A～21c) is supplied to the transistor 23a~23c emitting circuit C via a buffer circuit 22a~22c You. In the light emitting circuit C, the transistors 23a to 23c are sequentially turned on and off, whereby the light emitting diodes 25a to 25c are sequentially turned on and off. On the light emitting diode 25a~25c are sequentially turned off to when the optical gate signal S _3a to S
_3c is sequentially applied to the optical thyristors 3a to 3c, and the optical thyristors 3a to 3c are sequentially turned on and off. That is, when the light emitting diode 25a is on, the U-phase optical thyristor 3a of the rectifier E is turned on, and when the next light emitting diode 25b is on, the U-phase optical thyristor 3b and the light emitting diode 25a are turned on.
When c is on, the U-phase optical thyristor 3c is turned on, and the same U-phase optical thyristor is sequentially turned on in synchronization with the power supply frequency. When the load current of the rectifier E increases, the input current also increases, and the current detection signal Id also increases. As the current detection signal Id increases, the deviation from the matching circuits 8 and 18 increases. When the deviation value of the matching circuit 8 increases, the phase control circuit 11 performs an operation to advance the firing phase of the optical thyristor and generates an output. Further, when the deviation value of the matching circuit 18 increases, the comparator 19 generates an output signal, which is applied to the OR gates 20a to 20c. The output signal of the comparator 19 and the pulse signals from the gate pulse signal generation circuits 12a to 12c are input to these OR gates, but the signal from the comparator 19 has priority. Thus, the gate signal S _1a to S _1c of the same phase AND gate 21a~2
1c, and the signal from the gate pulse signal generation circuits 12a to 12c and the AND condition of the transistor 23 of the light emitting circuit C
a to 23c are all turned on and off regardless of the power supply frequency.
When the transistors 23a to 23c turn on and off at the same timing, the optical thyristors 3a to 3c of each switching arm D (FIG. 1) also turn on and off at the same timing. Further, when the load current decreases after a lapse of time, the switching is performed again so that the gate signal is sequentially applied to all the elements of each switching arm D one by one. Therefore, as compared with the case where a gate signal is constantly supplied to the light emitting element, the load on the light emitting element is reduced in inverse proportion to the increase in the number of paralleled elements. It is particularly effective for thyristor rectifiers for railways. H. Effects of the Invention As described above, according to the present invention, a plurality of light emitting elements used for ignition of a switching circuit formed by connecting a plurality of optical thyristors in parallel are selectively gated according to a load current. Since the signal is applied, the life of the light emitting element can be extended, and a highly reliable switching circuit can be obtained.

BRIEF DESCRIPTION OF THE DRAWINGS FIGS. 1 and 2 show an optical thyristor gate control device according to an embodiment of the present invention, FIG. 1 is an overall configuration diagram of the optical thyristor gate control device, and FIG. FIG. 3 is a waveform diagram of a main part of the circuit shown in FIG. 1 ... current transformer, 2 ... transformer, 3a to 3c ... optical thyristor, 14 ... ring counter, 20a to 20c ... or gate,
21a to 21c: AND gate, 25a to 25c: Light emitting diode, A: Gate signal generation circuit, B: Light emission control circuit,
C: light emitting circuit, D: switching arm, E: rectifier.

Claims (1)

(57) [Claims] In a gate control device, a rectifier is formed by bridging a switching arm formed by connecting a plurality of optical thyristors in parallel, and the plurality of optical thyristors of the switching arm of the rectifier are turned on and off, respectively. A gate signal generation circuit that generates a gate signal having a phase corresponding to the current flowing through the switching arm; and a plurality of numbers corresponding to the number of the plurality of optical thyristors connected in parallel based on a signal synchronized with the frequency of the current. A ring counter that generates a pulse train signal, a simultaneous conduction signal that is generated on condition that the current flowing through the switching arm is equal to or greater than a set value, and one of the plurality of pulse train signals as an OR condition, A plurality of OR gates corresponding to the number of the parallel optical thyristors that output signals based on the plurality of OR gates; A light emission control comprising a plurality of AND gates corresponding to the number of the parallel optical thyristors that output a light emission control signal with each output signal of the plurality of OR gates and a gate signal generated from the gate signal generation circuit being an AND condition A gate control device for an optical thyristor, comprising: a circuit; and a light emitting circuit having a light emitting element that operates in response to the light emission control signal and supplies an optical gate signal to the plurality of optical thyristors.