A resonant modular multilevel DC-DC converter with zero current switching for MVDC application

This paper presents a modular multilevel dc-dc converter (MMC) with zero-current switching (ZCS) feature and its analysis for medium-voltage direct current (MVDC) applications. The main focus of this paper is analyzing the overall efficiency of the proposed MMC and experimentally verifying the theoretical analysis on operating principle. Furthermore, in order to achieve high efficiency, the proposed MMC has the capability to maintain ZCS operation at different load conditions. In this paper, the proposed MMC with maximum 200kW power output is used to perform the efficiency analysis. Simulation uses the same parameters that are used to analyze efficiency and displays waveforms when the MMC operates at 66kW. At last, a 200W lab prototype has been built. And operating characteristics of the MMC are validated through experimental results.