State-Variable Steady State Analysis of a Phase-Controlled Cycloconverter-Induction Motor Drive

An attempt to obtain directly the steady state performance of a phase-controlled cycloconverter-induction motor system by using state-variable techniques is presented. State-variable approach is used to generate without iteration, the unique set of initial conditions which will yield the steady state solutions instead of going through the transient state as by the step-by-step method. The induction motor is represented as a two-axes model, and the cycloconverter model used is as developed in an earlier paper by the authors. A suitable digital program is evolved making simplifying assumptions, and in one approximate method of analysis suggested, initial currents are obtained without matrix inversion, thus saving computer time. Computer results of the performance of the system are presented and typical results are compared with experimental results as well as with the results obtained by other methods.