Hysteresis current regulation for single-phase multilevel inverters using asynchronous state machines

This paper describes the use of asynchronous state machines for the hysteresis current regulation of multi-level inverters. The state machines exploit the redundant states in order to balance the switching losses between the semiconductor devices, and to balance the voltages across the capacitors of topologies with series connected capacitors. The current regulators achieve a robust transient and steady state operation that fully utilises both the multiple DC levels available and the redundant states. Theory, simulation and experimental results are presented.