Design and Control Techniques for Extending High Frequency Operation of a CSI Induction Motor Drive

An investigation of the maximum speed capability of a current source inverter (CSI) drive in both a three-and a six-phase connection is presented. It is shown that a six-phase configuration has distinct advantages over a three-phase connection in high speed capability for the same peak motor spike voltages. In addition, with proper control of the firing pulses fed to the inverters supplying the six-phase machine, the speed range can be substantially extended beyond the maximum limit predicted using conventional control. Predicted analytical results are correlated with results obtained by a detailed hybrid computer simulation.