Analysis of dynamic performance of multilevel modulators with switching pattern restricted to single voltage level steps

Switching pattern in multilevel inverters has to be restricted to single voltage level steps to limit the overvoltages caused by the cable reflections and du/dt. This restriction affects not only the single-phase voltage pattern but the maximum allowed change of a voltage reference vector in three-phase operation and as a result also the maximum achievable frequency of the reference. These together can be perceived to determine the dynamical characteristic of the multilevel modulation schemes. Methods to determine the boundaries inside which these characteristics are valid are presented in this paper.