SU363965A1 - ACCURATE LOW-THROUGH AC CONTROLLER - Google Patents

Description

one

Pulse-width regulators of alternating current are known, containing counter-connected thyristors connected in the primary circuit of a power transformer, a saturating transformer with a primary winding connected to the supply circuit, one of the output windings of which is connected to the thyristor the other through the separation diode and the output key of the pulse-width control circuit to the control electrode of the second thyristor.

A disadvantage of the known regulators is that in each switch-on interval the regulator's thyristor turns off when the load current passes through zero, i.e., with a certain delay angle relative to voltage passing through zero, the turn-on of the thyristor at the beginning of each switch-on interval usually produced at the time of passage through the " zero voltage.

Therefore, the volt-second area is larger than the calculated one, and at the end of the first half-period the core of the power transformer is saturated, its magnetizing current rises sharply, which leads to deterioration of the energy performance and the regulator thyristors. The aim of the invention is to increase

energy performance and protection of thyristors regulator. This goal is achieved by parallel to the second output winding of the saturable transformer, via an isolating diode, an output of an adjustable phase shifter is connected, and the output pulse of the phase shifter connects the second thyristor at the beginning of each switch-on interval with a certain

phase shift.

The schematic of the pulse-width AC regulator is shown in the drawing.

The regulator consists of two opposing parallel-connected thyristors /, 2, included in the primary winding of the power transformer 3; saturating the transformer 4, one of the output windings of which is connected to the control electrode of the thyristor / through diode 5, and the other through the separating diode 6 and the output key 7 of the pulse-width control circuit to the control electrode of the thyristor 2; phase-shifting device 8, containing an input transformer 9, a pre-amplifier made on a transistor 10, a pulse shaper, made in the form of a blocking generator on a transistor //. Potentiometer 12 changes the phase of the output pulses of the phase shifter relative to the mains voltage.