Analysis and Performance of Three-Phase Phase-Controlled Thyristor AC Voltage Controllers

A simple generalized approach, based on numerical evaluation of the Fourier coefficients, is presented to evaluate the comprehensive performance of three-phase phase-controlled thyristor ac voltage controllers. Three-phase balanced resistive and inductive loads of different power factors are considered. The method of solution adopted is simple, accurate, fast, and does not require the derivation of Fourier coefficient equations. Various electrical properties are compared graphically for the different circuit configurations. The branch-controlled deltaconnected load is considered to have the best performance, giving the highest power factor per unit of power delivered.