A Microcomputer-Based High Power Cycloconverter-Fed Induction Motor Drive

A variable speed induction motor drive system fed by a high power cycloconverter is developed. The cycloconverter consists of two 36-thyristor subcycloconverters connected in series to minimize the input reactive power. Vector control for the induction motor provides stable and quick responses equivalent to those of DC motors. Asymmetrical voltage control, neutral potential bias control, and polar co-ordinate current control contribute the high performance operation of the cycloconverter. Multiple microcomputers realize these controls.