Cascaded Symmetrical Series Half-bridge Cells Multi-level Inverter

摘要

A cascaded structure has always been preferred in multilevel converter configurations because of its modularity, use of low-rated components to achieve high-quality output voltage waveforms, fault-tolerance/reliability, ease of design, and series expansion to desired voltage levels. This article presents a configuration for a cascaded multi-level inverter with a reduced number of power circuit component counts in each of the cascaded modules. Operational principles and control strategy of the inverter are discussed. A comparison is made among the proposed inverter, a classical CHB inverter, and some of the recently developed multi-level inverter topologies with respect to specified figures of merit as well as per unit power losses. For two cascaded modules, a simulation study of the performance of the proposed inverter under dynamic amplitude modulation index and load operations is also carried out. For an R-L load, experimental results from a prototype of the inverter are adequately incorporated.