Research on the Topology of Hybrid Cascaded Multilevel Converters

The spread of multilevel converters in high- voltage and large-capacity fields is restrained due to complicated topologies, therefore some new topologies are proposed continuously in recent years. In this paper, a detailed ananysis of novel cascaded multilever converters is included. The PWM stategy and rectifier topology of hybrid cascaded converters, which have the most applicable value, is improved to solve the problems that the reverse current of DC bus and the harmonic suppression of rectifier. On this basis, the topology of hybrid cascaded multilevel converters for 3-10kV drives is proposed, and the simulation and experimental results are presented. The proposed converter accords with the develop character of the present semiconductor devices, and optimizes the conventional cascaded converter structure.