Application of TCA785 in thyristor AC voltage regulation system

Used in thyristor AC voltage regulation system. Thyristor AC voltage regulation systems
are widely used in voltage regulation and speed regulation systems of high-power electrolytic plating devices and AC motors
. The principle circuit of TCA785 used in such systems is shown in Figure 12-9. The figure only shows the schematic diagram of a single-phase AC voltage regulation circuit composed of one piece of TCA785. A three- phase AC voltage regulation system can be formed
by using the same three circuits . In the figure, in order to enhance the triggering capability and facilitate the application of high-power thyristors , the output capability of the TCA785 is expanded, and a pulse transformer is used for isolation to completely isolate the main loop from the phase-shift control circuit .