Multi-state commutation cells to increase current capacity of multi-level inverters

This paper presents four generalized multi-state switching cells to increase current capacity, output voltage levels, and power processing of multi-level inverters. Such cells are named of multi-level multi-state switching cell (ML-MSSC), neutral point clamped multi-state switching cell (NPC-MSSC), flying capacitor multi-state switching cell (FC-MSSC), and H- bridge multi-state switching cell (HB-MSSC). Using the multi- state switching cells, single phase, three phase, and polyphase inverters can be generated for high power and high input bus voltage applications. In order to validate the theoretical assumptions, a particular application that consists of a five-level NPC inverter is studied, designed, and implemented in laboratory. Experimental results from a lOkW prototype are then obtained and relevant issues are discussed.