SU1474812A1 - Ac-to-ac discretely regulated thyristor converter - Google Patents

Abstract

The invention relates to electrical engineering. The purpose of the invention is to increase reliability and provide dual-mode control. The voltage is controlled by varying the switching angle of the triac. The triac switching angle depends on the presence of a signal at one of the pins 15 or 16. Depending on the presence of a signal at pin 15 or 16, the counting input of the counter 13 receives a signal from one of the pulse generators 1 or 2, which generate pulses of different frequency. When the device is turned on, the output 17 is given a start signal, which prohibits the operation of the counter 13 before the arrival of the synchronization pulse and prohibits the signal to turn on the triac before the one-shot 14 is turned on, thereby achieving the goal. 2 Il.

Description

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The invention relates to electrical engineering, namely to converter technology, and can be used in automatic voltage control systems, where automatic switching of the load to two different power modes using thyristors or triacs is required.

The purpose of the invention is to increase reliability and provide dual-mode control.

FIG. 1 shows a diagram of the device; in fig. 2 shows diagrams explaining the operation of circuit elements.

A discretely-controlled thyristor AC voltage to AC converter consists of the first and second pulse generators 1 and 2, the five logical elements AND 3–7 of the HE 8 logical element, the amplifier 9 control pulses, the driver 10 clock pulses, having pin 11 for connection to the mains supply voltage of the trigger 12, the counter 13, the one-shot 14. And the first and second logical elements AND-NOT 3 and 4 are connected respectively to the pins 15 and 16 of the mode switch. The control terminal 17 is connected to the input of the fifth NAND logic element 7.

The output of the first generator 1 im

0

0

connected via the logic element HE 8 and the amplifier 9 control pulses to the control terminal of the syistor.

The diagrams (Fig. 2) show: network voltage 18, clock pulses 19, pulses 20 of the first and second pulse generators 1 and 2, signal 21 at pin 17, pulses 22 at the output of the fifth logical element AND-HE 7, pulses 23 at the output of the counter 13, the pulses 24 at the output of the one-shot 14, the pulses 25 at the output of the logical element AND-NOT 6, the pulses 26 at the output of the logical element HE 8, the pulses 27 at the output of the amplifier 9 control pulses, the pulses 28 at the output of the trigger 12 The diagrams are given when the first pulse generator 1 is operating. When you turn on the work of the second generator 2 pulses in charts 29-31 are given respectively the pulses at the outputs of the counter 13, the one-shot 14 and the trigger 12.

The discrete-adjustable AC-to-voltage converter operates as follows.

When the first generator 1 of pulses is put into operation, for example, which is predetermined by the presence of the state of a logical unit at pin 15, its pulses arrive at the first input

five

0

pulses connected to the input of the first lo-35 of the third logical element AND-NOT

the main element AND-NOT 3, and the output of the second generator 2 pulses connected to the input of the second logic element AND-NOT 4. The outputs of the first and second logic elements AND-NOT 3 and 4 are connected to the inputs of the third logical element AND-NOT 5, the output of which is with the counting input of the counter 13. To the output of the counter 13 is connected the one-shot 14, the output of which is connected to the input of the fourth logical element AND-NOT 6. The output of the fourth logical element 6 is connected to the input of the fifth logical element AND-NOT 7, the output of which is connected to the S-input trigger 12, to the C-input of which a signal is supplied from a shaper of 10 sync pulses connected to pin 11 for connection to a source of supply voltage. The output of the trigger 12 is connected to the input R of the counter 13, and the output 17 to the input of the fourth logical element AND-NOT 6, the output of which

5 and from its output to the counting input of the counter 13. Filling of the decades of the counter 13 begins after the enabling zero signal from the output of the trigger 12 arrives at its R input. The trigger 12 is reset to the zero state when the sync pulse arrives at its C input at provided that a logical zero level is present at the S-input, which is ensured by feeding a logical unit to pin 17. After filling them at the output of the counter 13, the state of the logical unit will be set. As a result, the one-shot 14 triggers and generates a pulse of the duration necessary to turn on the triac. This pulse is inverted by the fourth AND-NOT 6 logic element and is fed to the input of the logical element HE 8 and the fifth logical element AND-NOT 7. The pulse at the output of the logical element NO 8 is amplified by the amplifier 9 and from its output goes to the control

3,147

the triac electrode, which is turned on for the remaining half-period of the mains voltage and a voltage is applied to the load

A zero control pulse from the output of the fourth AND-NOT 6 logic element, arriving at the input of the fifth AND-NOT 7 logic element and inverting, results in the appearance of a logical unit signal on the trigger 12, which is fed to the P input of the counter 13. In this case all decades of the counter 13 are zeroed and the counter-frequency divider 13 is disabled until the next clock pulse arrives, which will turn the trigger 12 into the logical zero state at its output. Then the whole cycle repeats.

The operation of the discrete thyristor dual-mode voltage regulator from the second generator 2 of control pulses proceeds in a similar way. To do this, it is necessary that the state of the logical unit be set at the first input of the second logical element IS-NO 4, and the state of the logical zero at the first input of the first logical element IS-NOT 3.

By tuning the first and second generators 1 and 2 pulses to a different frequency, you can get any two necessary modes of operation of the voltage regulator.

Claims (1)

Invention Formula Discrete adjustable thyristor variable voltage converter B variable, containing a clock generator, having an input for connecting to a source five 25 20 thirty five 0 supply voltage meter, a counter, a first pulse generator, a control pulse amplifier connected to a control terminal of a triac connected to a load circuit, characterized in that, in order to increase reliability and provide dual-mode control, a second pulse generator, a trigger, is inserted, a one-shot, five NAND logic elements and a NO element, two mode switching pins, the output of the first pulse generator connected to the input of the first NAND logic element, the other input of which is connected to the first the mode switching water, and the output to the input of the third NAND logic element, the output of the second pulse generator is connected to the input of the second NAND logic element, the other input of which is connected to the second output of the mode switching, and the output to the input of the third I AND logic element NOT, the output of which is connected to the counting input of the counter, and the output of the counter through the one-shot is connected to the input of the fourth NAND logic element, the output of which is connected to the input of the NAND logical element and the input of the 5 NI logical element, the input of which is connected to the control output and the input of the fourth NAND logic element, where the output of the logic element is NOT connected to the input of the control pulse amplifier, the output of the sync pulse generator is connected to the counting input of the trigger, the direct output of which is connected to the R input of the counter, and S -Input - to the output of the p of the logical element 2I-NOT. kA IF F 1 i I / h St 27 i fl I P fl l And qnq 43- -43- -4 rl L k-gj U i Ј. . "- J L one A k rl one P one z