A Cascaded Modular Multilevel Inverter Topology Using Novel Series Basic Units with a Reduced Number of Power Electronic Elements

摘要

In this study, a new type of cascaded modular multilevel inverters (CMMLIs) is presented which is able to produce a considerable number of output voltage levels with a reasonable number of components. Accordingly, each series stage of the proposed CMMLI is comprised of two same basic units that are connected with each other through two unidirectional power switches without aiming any of the full H-bridge cells. In addition, since the potentiality for generating a higher number of output voltage levels in CMMLIs hinges on the magnitude of the dc voltage sources used in each series unit, in the rest of this paper, four different algorithms for determining an appropriate value for the dc sources' magnitude are also presented. In the following, a comprehensive topological analysis between some CMMLI structures reported in the literature and proposed structure along with several simulation and experimental results will be also given to validate the lucrative benefits and viability of the proposed topology.