Research on hybrid modulation strategies based on general hybrid topology of multilevel inverter

Based on the research on several multilevel basic topologies, this paper presents a general type of multilevel hybrid topology and introduces several selectable degrees of freedom. No matter what change in the hybrid topology it can be resulted in the combination and selection of the degrees of freedom, which expands the topology collection of the multilevel inverter. According to the degrees of freedom, all the cascaded topologies have been unified and several new types of hybrid topologies have been constructed. Based on the research on the hybrid topologies and multi-carrier SPWM (Sinusoidal Pulse Width Modulation) used for the multilevel inverter, this paper presents the hybrid modulation strategies for hybrid topologies. Simulation results prove that hybrid topologies and corresponding modulation strategies are effective, which lay the foundation for practical application of hybrid multilevel inverter topologies.