Five-Level Inverter Topology for IM Drive With DC-Link Capacitor Voltage Balancing and Common-Mode Voltage Elimination in Complete Modulation Range

Abstract

This paper presents a five-level inverter topology for induction motor (IM) drive with dc-link capacitor voltage balancing and common-mode voltage elimination. A dual fivelevel inverter fed open-end winding IM structure is used in the present work. A hysteresis controller based closed loop control scheme is proposed. It achieves the balancing of dc-link capacitor voltages and elimination of common-mode voltage, together, in the complete modulation range of the drive, including the over modulation up to the 24-step mode operation. The controller is capable of providing the capacitor voltage balancing and common-mode voltage elimination in the motoring as well as regenerative mode of operation. The proposed control scheme does not affect the fundamental output voltage generated by the inverter, as it effectively utilizes the availability of redundant switching states for capacitor voltage balancing. The scheme is presented with the simulation studies and experimentally verified with a 1.5 kW open-end winding IM drive.