A Proposal of Modular Multilevel Converter Using a Three-winding Transformer

Abstract

This paper proposes a new type of Modular Multilevel Converter (MMC) using a three-winding transformer. In general, MMCs require a buffer reactor in each arm, which increases the number of components required in the converter and the converter footprint. The proposed MMC with a three-winding transformer does not require buffer reactors. The mathematical representation of the proposed converter was first described. The operational performance of the proposed MMC was found to be identical to the typical MMC (with the buffer reactor topology) by making comparisons in the experimental tests on two physical prototype converters rated at 10 kVA.