The hybrid inverter fed motor drive with two cascaded multilevel inverters is an attractive option for high performance high power applications such as naval ship propulsion systems due to a number of unique features. There is a natural split between a higher-voltage lower-frequency "bulk" inverter and a lower-voltage higher-frequency "conditioning" inverter in the cascaded system which matches the availability of semiconductor devices. Furthermore, the bulk inverter may be a commercial-off-the-shelf (COTS) motor drive meaning that only the conditioning inverter needs to be custom made. However, a drive involving a COTS bulk inverter would require a distributed conditioning inverter control which works completely independent of the bulk inverter control. In this paper, a set of distributed control methods are developed for the hybrid inverter drive with cascaded bulk and conditioning inverters, requiring only single dc source. Moreover, a solution to the practical problem of instant synchronization between the two inverters is presented. Laboratory measurements on a 3.7-kW induction motor drive validate the proposed control. Various practical considerations (such as low m-index performance and capacitor precharging options) are discussed and their solutions provided.


Electrical and Computer Engineering

Keywords and Phrases

Commercial-Off-The-Shelf (COTS) Motor Drive

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 Sep 2006