Dynamic Performance of a Closed-Loop Induction Motor Speed Control System with Phase-Controlled SCR´s in the Rotor

The dynamic behavior of a closed-loop variable-speed induction motor drive system which uses three phase-controlled silicon-controlled rectifiers (SCR´s) connected in delta configuration and placed at the open star point of the rotor circuit is investigated. The various functional blocks of the system which govern the behavior of the system for small variations about the operating point are derived, and the responses for load and reference speed perturbations are obtained analytically. The analytical results are compared with experimental values.