Performance Enhancement of Modular Multilevel Converter for Motor Drive Application

Abstract

Modular Multilevel Converters (MMCs) have gained prominence in medium- and high-voltage applications due to their modularity, scalability, and ability to achieve high power quality with low harmonic distortion. However, one of the critical challenges in MMC-based drives is the presence of circulating currents among converter submodules. These circulating currents, typically induced by unbalanced capacitor voltages and phase asymmetries, can lead to increased power losses, thermal stress on submodule components, and ultimately, reduced drive efficiency and lifespan. To control the circulating current in MMC, this paper proposed circulating current control technique which could be able to reduce the circulating current from rated speed to low speed operation under steady state and transient operation. Details waveform analysis is presented in detail. The MALAB based simulation is carried out to check the effectiveness of proposed technique. The details comparison between proposed technique and conventional technique is presented.