JPS5866572A - Phase control gate pulse generating circuit for thyristor converter - Google Patents

Abstract

PURPOSE:To accurately control a pulse shift by enabling to instantaneously shift a gate pulse at the time of generating an overcurrent of a thyristor converter. CONSTITUTION:When an overcurrent is generated in a normal operation state, an overcurrent state input signal 202 is inputted to a control angle alpha setting circuit 20. Then, the circuit 20 feeds an overcurrent state signal to a signal switching circuit 24, thereby instantaneously switching the output signal 201 of a gate pulse generating circuit 8 to a signal 200. Accordingly, an overcurrent counter 21 has already started counting, but continues as it is, and returns to 0 after the prescribed time, at which it outputs a gate pulse 107 to a thyristor 11. Consequently, since the gate pulse shift can be instantaneously performed, the gate pulse shift is not delayed by half period.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a phase-controlled gate pulse generation circuit for a thyristor conversion device, and particularly to a gate pulse generation circuit for a thyristor conversion device suitable for instantaneously shifting gate pulses to protect the thyristor conversion device from overcurrent. The present invention relates to a phase control gate pulse generation circuit.

A conventional phase control gate pulse generation circuit of this type of thyristor conversion device is constructed as shown in FIG.

In the block diagram shown in FIG. 1, symbols 1 to 3 are level conversion circuits, 4 is a synchronization circuit, 5 to 7 are counters, and 8 to 1
0 is a gate generation circuit, 11 is a gate pulse distribution circuit, 1
2 is a three-phase Xyrister bridge, 13 is a load, and 14 is a control angle α setting circuit.

In order to synchronize with the voltage 100 of a power supply (not shown) connected to the three-phase thyristor bridge 12 of the thyristor conversion device, the voltage 100 is converted into a digital signal 1 by the level conversion circuit 1.
01 and supplied to the synchronization circuit 4. The synchronization circuit 4 forms a count start signal 102 synchronized with the power supply voltage 100 and supplies it to the counter 5. The counter 5 starts counting in response to the count start signal 102, and stops counting when the control angle α setting value from the control angle α setting circuit 14 is reached. This counter 5
The output signal of is output as signal 104. Still, the control angle α setting circuit 14 controls the thyristor bridge 1 of the thyristor conversion device by inputting the control angle α signal 103.
The control angle α can be set according to the state of the load 13 connected to the motor 2. In particular, the control angle α setting circuit 14 outputs the control angle α in normal times according to the control angle α signal 103, and outputs the control angle α2 when an overcurrent condition is detected to perform the gate pulse 7-ft. It has become.

On the other hand, the count result signal 104 of the counter 5 is input to the gate pulse generation circuit 8, and the gate pulse generation circuit 8 generates the gate pulse 105 based on this count result signal 104.
is supplied to a thyristor bridge 12 of a thyristor conversion device via a gate pulse distribution circuit 11.

The operation of the phase-controlled gate pulse generation circuit configured as described above will be explained based on the time chart shown in FIG. In FIG. 2, the horizontal axis represents time, and each vertical axis represents the signal of the portion of FIG. 1 having the same symbol as that shown therein. As shown in the time chart of FIG. 2, even if the signal state signal 103 rises at time t2 and the control angle α2 for performing the gate pulse shift is set, the counter 5 has already started counting at time t1. The disadvantage is that the gate pulse is output in the process, and the pulse shift is delayed by half a cycle.

An object of the present invention is to provide a highly reliable and inexpensive phase control gate pulse generation circuit for a Cyrisk conversion device by enabling instantaneous gate pulse shift without a half-cycle delay when an overcurrent occurs in the Cyrisk conversion device. There is something to do.

In order to achieve the above object, the present invention consists of two counters: a control angle α counter and an eddy current counter that operate in synchronization with the power supply voltage, and the control angle α counter is usually used. However, when an overcurrent occurs, the switching gate pulse is shifted to the overcurrent counter.

Hereinafter, one embodiment of the present invention will be described in detail based on the drawings.

FIG. 3 is a block diagram showing one embodiment of the present invention.

As shown in this figure, this embodiment includes level conversion circuits 1 to 3 for converting the power supply voltage into digital signals, a synchronization circuit 4 for synchronizing with the power supply voltage, and counters 5 to 3 having two circuits for each phase. 7.21-23, signal switching circuits 24-26,
The gate pulse generation circuit 10 includes gate pulse generation circuits 8 to 10, a gate pulse distribution circuit 11 made up of logic circuits, and a control angle α setting circuit 20. That is, counters 5 to 7 in FIG.
In FIG. 2, control angle α counters 5 to 7 and overcurrent counters 21 to 23 are respectively configured, and in normal times, the count result output signal from the control angle α counters 5 to 7 is used. When an overcurrent occurs in the converter, the count result output signals from the overcurrent counters 21 to 23 are used. - To explain further in terms of phases, the control angle α counter 5 and the overcurrent counter 21 are configured to start counting in response to a start signal 102 from the synchronization circuit 4, and transmit the count results to the signal. The signals are supplied to the switching circuit 24, respectively. The output signal from the control angle α setting circuit 20 normally supplies the counter result of the control angle α counter 5 to the gate pulse generation circuit 8 via the signal switching circuit 24, while the overcurrent state input signal 202 When input to the control angle α setting circuit 20, the signal switching circuit 24 is switched to supply the count result signal 200 of the overcurrent counter 21 to the gate pulse generation circuit 8. That's all -
Although the phase has been described, the other phases are similarly configured.

The operation of this embodiment will be explained for one phase with reference to the time chart of FIG. FIG. 4 is a time chart shown to explain the operation of this embodiment, in which the horizontal axis shows time, and the vertical axis shows the symbols in FIG. Partial signals are shown. In the figure, a power supply voltage input 100 is converted into a digital signal 101 by a level conversion circuit 1. The synchronization circuit 4 from the digital signal (i-9) output from the level conversion circuits 1 to 3 of each phase forms a count start signal 102.

The control angle α counter 5 and the overcurrent counter 21 start counting at the set value α from the control angle α setting circuit 20.

and set value α Return to II OIT after 2 hours (Fig. 4 1
04, 200), the signal switching circuit 24 receives the overcurrent state signal from the control angle α setting circuit 20, and outputs the signal 104 in the case of an overcurrent state and the signal 200 in the case of normality to the gate pulse generation circuit 8. do.

The gate pulse generation circuit 8 receives an input signal 201 from II O
When returning to II, a pulse output with a pulse width of 1w is output to the gate pulse distribution circuit 11. The gate pulse distribution circuit 11 distributes gate pulses to six thyristors.

In a normal operating state, when an overcurrent occurs at time t2, an overcurrent state input signal 202 is input to the control angle α setting circuit 20. Then, the control angle α setting circuit 20 sends the overcurrent state signal to the signal switching circuit 24, and instantly switches the output signal 201 to the gate pulse generating circuit 8 to the signal 200. Unfortunately, the overcurrent counter 21 has already detected time t,
Counting starts with , but if you continue counting, it will return to '0'' at time (/3), and at this point, thyristor 1 will start counting.
A pulse 107 is output. Therefore.

Since gate pulse shifts can be performed instantaneously,
The gate pulse shift will not be mistaken for half a cycle.

As mentioned above, this embodiment is highly accurate and inexpensive.
Furthermore, it is possible to realize a digital phase control gate pulse generation circuit that can instantaneously shift gate pulses. Furthermore, a digital phase control gate pulse generation circuit can be constructed under microcomputer control.

According to the present invention, as described in (2) below, it is possible to instantaneously shift the gate pulse when an overcurrent occurs in the thyristor converter, so that it is possible to achieve highly accurate pulse shift l-control, and to reduce the cost of the phase control gate of the thyristor converter. This has the effect of providing a pulse generation circuit.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing the gate pulse generation circuit of a conventional thyristor conversion device, Fig. 2 is a time chart showing the state of the gate pulse shift when an overcurrent occurs in the block diagram of Fig. 1, and Fig. 3 is A block diagram showing one embodiment of the present invention, and FIG. 4 is a time chart showing the state of gate pulse shift when an overcurrent occurs in the embodiment of FIG. 3. 4...Synchronization circuit, 5-7...Counter for control angle α, 8-10...Gate pulse generation circuit, 12...3
Phase thyristor bridge, 13... Load, 20... Control angle α setting circuit, 21-23... Overcurrent counter,
24-26...Signal switching circuit, 100...Power supply voltage input, 102...Count start signal, 104...
・Counter output signal, 105... Gate pulse, 10
6...Up gate pulse, 107...UN game]・
Pulse, 200... Counter output signal for overcurrent, 20
1...Signal switching circuit output signal. Agent Patent Attorney Akio Takahashi

Claims (1)

[Claims] ■. A synchronization circuit that synchronizes with the voltage of the power supply connected to the thyristor conversion device, and a control angle α that controls the control angle α to the thyristor according to the load condition of the thyristor conversion device. a setting circuit, a counter that starts counting based on a signal from the synchronization circuit and stops counting when the count value reaches a set value from the control angle α setting circuit; In the phase control gate pulse generation circuit of a thyristor conversion device, which includes a gate pulse generation times generation circuit, the counter is composed of a counter for control angle α and a counter for overcurrent, and under normal conditions, the counter for control angle α In addition to outputting the count result from the overcurrent counter when the thyristor converter overcurrent occurs, the gate pulse to the thyristor is instantaneously shifted to the gate pulse. Phase gate pulse generation circuit for thyristor converter.