In the past decade, the multilevel power converter has transitioned from an experimental concept to a standard product of many medium-voltage drive manufacturers. By utilizing small voltage steps, the multilevel topology offers higher power quality, higher voltage capability, lower switching losses, and improved electromagnetic compatibility over standard topologies. Recently, several researchers have focused on the cascaded multilevel inverter whereby two multilevel inverters are series connected to a motor load by splitting the neutral connection. The resulting performance is exceptional in terms of power quality since the overall number of voltage levels is effectively the product of the two cascaded inverters. This paper demonstrates that it is possible to extend this performance to an even higher number of voltage levels referred to as overdistended operation. This further improves the power quality that is significant in applications that have stringent total harmonic distorsion requirements, such as naval ship propulsion. A new control is introduced for overdistention operation and is validated with computer simulation and laboratory measurements.


Electrical and Computer Engineering

Keywords and Phrases

Multilevel Converter; Cascaded Multilevel Inverters; Electromagnetic Compatibility; Harmonic Distortion; Invertors; Motor Load; Multilevel Inverter; Multilevel Power Converter; Multilevel Topology; Overdistention Operation; Power Convertors; Power Quality; Power Supply Quality; Pulse-Width Modulation; Space Vector; Switching Losses; Total Harmonic Distortion

International Standard Serial Number (ISSN)


Document Type

Article - Journal

Document Version

Final Version

File Type





© 2006 Institute of Electrical and Electronics Engineers (IEEE), All rights reserved.

Publication Date

01 May 2006