Evaluation of a Matrix Modular Multilevel Converter Based on a Series-Parallel Converter

The Matrix Modular Multilevel Converter (M3C) is a promising solution for medium-to-high voltage AC/AC conversion, due to its small size by not requiring an intermediate DC-link and its reduced arms compared to a back-to-back scheme. This paper introduces an M3C based on Modular Multilevel Series-Pararell Converter (MMSPC) modules, enabling sensorless voltage balancing between modules to simplify the control scheme needed in the converter. This module, however, introduces overcurrent risk due to the sensorless balancing operation, to solve this, port inductances are incorporated while the commutation frequency is increased. This paper shows a simulation of an M3C based on MMSPC modules, interconnecting two AC systems with a top port inductance configuration and a commutation frequency of 2000 Hz. The results show that an M3C based on MMSPC reduces the control complexity while the top port inductance with the increased frequency reduces the overcurrent risk and improves the converter performance, making it a promising configuration for an optimized M3C for industrial uses.