Three-phase circuits with voltage control by integral-cycle single-phase mode triggering of thyristors

Several configurations of balanced three-phase series RL loads are investigated to consider the feasibility of using thyristor control with integral-cycle triggering. The four-wire star-connected load, with pairs of thyristors in the supply lines and the delta-connection with pairs of thyristors in the load legs, are found to be suitable. Both connections result in similar load voltage and current waveforms. The branch-delta connection is considered to be preferable because the supply lines do not contain DC components of current.