Multilevel current source inverter-the switching control strategy for high power application

The generalized structure and control problem of a multilevel current source inverter using a generalized current multilevel cell are presented in this paper. The necessary control laws are established and the control problem of both seven-level and nine-level structures is studied. Optimizing the step width of the inverter output current ensures current harmonic reduction and even current distribution among the switches of the cell. The output harmonic content can be reduced without frequency modulation, which is imperative in high power applications such as interconnecting superconductive magnetic energy storage (SMES) to a power system.