A general carrier-based modulation and capacitor- voltage balancing method for multilevel matrix converters (AC-AC Stacked Multicell Converters)

Multilevel matrix converter (M2C) combines the benefits of direct AC to AC conversion and multilevel converters. It features compact structure, low current ripples and high- voltage and high-power capability. The cellular structure also benefits the power loop design and results in a clean switching transient especially when wide bandgap devices are used. However, documented modulation strategies for M2Cs are all space-vector based and extremely complicated. The control complexity makes these converters difficult to use in real application. In this paper, a general carrier-based modulation and flying capacitor voltage balancing method was proposed which drastically simplified the control of M2C, meanwhile it ensures a unity power factor at the supply side and a sinusoidal voltage at the load side. Simulation and experiment results were provided to verify the analysis.