Firing control circuit for synchronous electric machine - has capacitor in series with two antiparallel thyristors between two sets of thyristors

摘要

The firing control circuit for a synchronous electric machine fed from the mains supply (R,S,T) by an intermediate d.c. circuit includes a pair of thyristors for each phase. The three pairs of thyristors are connected by a smoothing inductance (Ld) to a further set of three pairs of thyristors (21 to 26) connected to the machine. Between the inductance and the second set is a capacitor (Cd) in series with two antiparallel thyristors (51,52). The excitation voltage of the machine is controlled so that the blocking voltage of the second set of thyristors (21 to 26) remains constant.