SIMULATION OF C°YCLOCONVERTER FED INDUCTION MOTOR DRIVE CONSIDERING STATOR CURRENT DISCONTINUITY

Abstract

A digital computer method of analyzing a complex variable-frequency drive system comprising a three-phase induction motor and a phase-controlled thyristor cycloconverter is presented. A generalized set of performance equations in d-q axes representation is first developed for the induction motor with the thyristor switchings in the source taking into account the discontinuities in the stator current. Using this generalized model effect of single phasing in all three phases is studied. Logic variables are used to represent thyristor switches, and the induction motor model thus developed is then combined with a phase controlled cycloconverter model for non-circulating current mode of operation. The combined model is then used in digital computer program to obtain dynamic and steady state performance of the system.