Sensorless scheduling of the modular multilevel series-parallel converter: Enabling a flexible, efficient, modular battery

Conference Paper

© 2016 IEEE. We present a control approach for the modular multilevel converter (MMC) with series and parallel module connectivity (MMSPC) that provides natural module balancing, reduced conduction losses, and enhanced robustness afforded by the parallel mode. In conventional MMC control, the voltage of each module's storage element has to be measured or estimated to enable the controller to equalize the voltages across all modules. This requirement has been one of the key barriers for MMCs in low and medium power applications. In contrast, we use the parallel connectivity of the MMSPC for module voltage balancing. It also enables robust operation in the presence of battery failure by supporting the module voltage with frequent parallelizations of the residual module capacitance. The parallel connectivity further reduces conduction losses at voltage levels below the system maximum by decreasing the effective source impedance. This approach renders attractive for the first time low and medium power MMC applications as well as MMC-based battery storage. These are illustrated with an experimental MMSPC system comprising eight battery modules that generates high-quality ac output without filtering magnetics.

Full Text

Duke Authors

Cited Authors

  • Goetz, SM; Li, Z; Peterchev, AV; Liang, X; Zhang, C; Lukic, SM

Published Date

  • May 10, 2016

Published In

  • Conference Proceedings - IEEE Applied Power Electronics Conference and Exposition - APEC

Volume / Issue

  • 2016-May /

Start / End Page

  • 2349 - 2354

International Standard Book Number 13 (ISBN-13)

  • 9781467383936

Digital Object Identifier (DOI)

  • 10.1109/APEC.2016.7468193

Citation Source

  • Scopus