Cascaded Modular Multilevel Converter for drive applications with zero common-mode voltage

Abstract

This paper presents a novel control strategy for the cascaded MMC for drive applications. The injection of high frequency circulating currents along with high frequency common-mode voltage is a frequent control strategy for the MMC in drive applications. However, this approach induces a voltage across the machine shaft and it will shorten the lifespan of the machine bearings. This paper proposes a novel control strategy to cancel the common-mode voltage seen by the machine using the cascaded MMC. Simulations results are presented to show the performance of the proposed controller.