SU505100A1 - Low Frequency AC to DC Voltage Converter - Google Patents

Description

one

The invention relates to the secondary sources of electronic powering of the automation and communication system and can be used to convert the alternating voltage of an industrial low-frequency network into a constant voltage.

The known voltage transformers of this class contain a series-connected input rectifier, high-frequency inverter and output rectifier with a smoothing filter.

The low frequency voltage pulsations in such converters are smoothed by the filter at the output of the converter, i.e., they are large in size and mass.

The purpose of the invention is to reduce the size and mass of the filter by bringing the output voltage to the rectangular shape.

This is achieved by performing an output transformer with primary winding taps, which are connected to additional switches controlled from the output rectifier output.

FIG. Figure 1 shows the circuit of the proposed converter in the transistor variant, where the 1-input rectifier; 2 - output transformer; 3–8 — power transistors operating in switching mode; 9-14 match schemes; 15 - master oscillator; 16 is a synchronization circuit; 17-

the control circuit is represented as a loop and a ring pulse distributor, the number of cycles of which is equal to the number of sections of the primary winding of the power transformer;

18 - pulse-width modulator; 19 - output rectifier with a smoothing filter; 20 - load; 21–24 Diodes.

Pa figs. 2 shows the timing diagram of the main nodes of the scheme. Here: a is the voltage form at the output of rectifier 1; b - impulses from master oscillator 15; c — pulses from coincidence circuits 11 and 12; g-pulses from coincidence circuits 10 and

13; e - nucleuses from coincidence schemes 9 and 14; and e is the voltage form at the input of the output smoothing filter 19.

The principle of operation of the circuit is as follows.

When the converter is connected to the network, the control circuit 17 by means of the circuit 16 is synchronized with the network frequency and, after passing the mains voltage through zero, first allows the operation of the matching circuits

Claims (1)

11 and 12. The master oscillator 15 continuously emits pulses with a frequency significantly higher than the network frequency (several units or tens of kilohertz). At the same time, to the output of the rectifier, they first appear at the node through transistors 5 and 6 of the primary windings of transformer 2 with the least number of turns. The period IKOMMVtirovaya transistor-p 5 and 6 is determined by the geyerator frequency l |, and the duty cycle of these pulses - by the latitude-pulse modulator 18, in which the comparison of the constant П; I on the load 20 with the reference voltage occurs; determined by the number of taps in the primary winding of transformer 2 (with three taps, this gap is -, the control circuit 17 opens the coincidence circuits 10 and 13 and allows the transistors 4 and 7 to work, and the transistors 5 and 6 are locked. The coil windings are through transistors 3 and 8. When the sinusoidal voltage coincides from amplitude to zero, the transistors turn on in reverse order. During the next half of the mains voltage period, the circuit works in the same way. Since the number of turns of the primary windings changes synchronously network voltage, and the number of turns of the output winding is constant, the voltage at the output of the converter is almost constant with the same level of output satsy. The DC voltage on the load 20 is stabilized by varying the width of the pulses taken from the nshrotpo-pulse modulator 18. The connecting diodes 21-24 serve to exclude inverse currents through the transistors. Claims of an Inverter AC Voltage Converter to Direct Voltage Containing an Inverter Rectifier Connected in Series, a High Frequency Inverter with an Output Transformer with Main Key Elements Controlled from a Driving Generator via a Pulse Width Modulator filter, characterized in that, in order to reduce the weight and size, the primary winding of the specified transformer has taps connected to the output of the rectifier through additional key elements which control circuit connected to the output of the coincidence circuit, one input of which is coupled to the output of the input rectifier and the other - with the output of the pulse width modulator. ABOUT Vus.2