SU957376A1 - Semiconductor converter control pulse shaper - Google Patents

Description

one

The invention relates to power converter technology and can be used in output stages of semiconductor frequency control systems controlled by rectifiers and power thyristors.

Devices for controlling power thyristors, containing a carrier frequency generator, two d transistor switches, a transformer, a rectifier, a zener diode, terminals for connecting a power source and a power thyristor Cl are known.

The closest to the proposed 5 is a device for controlling thyristors, containing a modulating frequency generator, a switch based on two transistors with a transformer, the output winding of which is connected via a rectifier to a terminal for connecting a control thyristor electrode, a control switch with an amplifier and terminals for connecting the power source and the control voltage source.

A disadvantage of the known devices is low reliability.

The purpose of the invention is to increase the reliability of the control pulse driver of semiconductor converters.

Claims (2)

The goal is achieved by the fact that the device is equipped with an external amplifier and an element, while the control key is three-positioned according to the amplifier circuit with a variable gain, and the middle point of the input winding of the transformer and the emitters of the output transistor transistors are connected to the current source, moreover, the source of control voltage is connected to one input of the control key and to the first input of the Element And, the second input of which is connected to the output of the generator , the output of the element I is connected to another 39 input of the control switch, the output of which is connected via an intermediate amplifier to the input of the output driver. The basic electrical circuit of the driver is shown. The driver contains a generator of 1 modulating pulses with the number of outputs corresponding to the number of control channels, the AND element 2 , a three-position control switch 3, an intermediate amplifier k, a switch 5 based on two transistors with a transformer, a rectifier 6. A three-position control switch 3 includes a control the transistor 7, the switching transistor 8 and the feedback amplifier 9. The shaper operates as follows. The modulating pulse generator 1 operates at a stabilized higher frequency fn 7, (l5-20) fp, where fp is the frequency of the pulses generated at the output of the device. Unipolar pulses from the generator outputs are fed to the input of the element I 2 of each channel, to the other input of which control pulses Uch are received; from a source of control voltage. At the same time, the control pulses are fed to one of the inputs of the control key 3 to the other input of which the generator pulses are modulated according to the frequency of the control pulses in element I. The key 3 converts the control pulses into two-pole pulses modulated by the generator frequency and supplies them to the input intermediate amplifier k. The intermediate amplifier controls the switching transistors 5. A variable modulated voltage is converted into a constant voltage by the rectifier 6 and is fed through the matching circuits to the power valves of the converter. The control key 3 is built according to the scheme of a push-pull amplifier with a variable gain and operates as follows. The control signals are fed to one of the inputs and fed to the base of the control transistor 7, which is controlled by a field-effect transistor 8 connected to the inverting input of the amplifier 9. Pulses from the generator promulgated at the control frequency are supplied to the drain of the transistor 8. and from the source, these pulses are transmitted to the input of the amplifier 9. Due to the displacement of the initial point of the amplifier, either a positive potential or a negative or zero is formed at its output (at zero potentials of the control signal). In the latter case, the operation of the switch transistors stops and they are closed. Due to the exclusion of switching elements and blocks with one-sided conductance, overvoltages in the circuits of the control key transistors are eliminated from the power supply circuits of the output switch, which increases the reliability of the driver. The operation of the amplifier and the switch only at permitted intervals leads to an increase in the efficiency. Claims of the invention Shaper of control pulses of semiconductor converters, comprising a modulating frequency generator, a switch on the basis of two transistors, c. a transformer, the output winding of which is connected via a rectifier to a terminal for connecting a control electrode of the thyristor, an amplifier control switch and terminals for connecting a source of control power supply and different voltage, in order to increase reliability, it is equipped with an intermediate amplifier and the element And, while the control key is made three-position according to the amplifier circuit with a variable gain, and the middle point of the input winding of the transformer and the emitters of the output transistors rmirovatel connected to corresponding terminals for connecting a supply source, wherein the source of control voltage is connected to one input of the control switch and to the first input of the AND, the second input of which is connected with. the output of the generator, the output of the element AND is connected with another input of the control key, the output of which is connected to the input of the output driver via an intermediate amplifier. Sources of information taken into account in the examination of 1, USSR Author's Certificate N 652663, cl. H 02 M 1/08, 1976. 2. Authors certificate of the USSR W 767910, cl. H 02 M 1/08, 1975. R