A Dual Five-Level Inverter-Fed Induction Motor Drive With Common-Mode Voltage Elimination and DC-Link Capacitor Voltage Balancing Using Only the Switching-State Redundancy—Part I

For a dual five-level inverter-fed induction motor (IM) drive, effects of DC-neutral currents on dc-link capacitor voltage fluctuations are analyzed in this paper. Operating limitations in achieving the dual task of common-mode voltage elimination and DC-link capacitor voltage balancing with a single dc power supply are further investigated for the proposed drive. In this paper, an open-loop control scheme, which uses only the availability of redundant switching states for the inverter control, is presented. Limitation of proposed open-loop control to take corrective action for any existing unbalance in capacitor voltages calls for a closed-loop control scheme, which is presented in Part II of this paper.