Analysis and performance of hybrid thyristor controlled three-phase resistive-inductive loads

The authors describe a method of analysis and performance characteristics of hybrid thyristor controllers for three-phase resistive-inductive loads. Different circuit configurations having full-wave or half-wave control are discussed. It is shown that, of the various configurations considered, the three-phase, three-wire, star-connected system with full-wave control offers the best overall performance. This has a sensitive range of power control over a wide range of firing angles. Line current distortion is small so that the circuit is characterized by high distortion factor and high input power factor. For some applications, such hybrid power controllers appear to be more suitable than conventional thyristor power controllers