Multilevel Current Source Inverter Topologies Based on the Duality Principle

This paper explores the issue of constructing multi-level current source inverter (MCSI) topologies using the duality principle. In order to extend the application of duality to the three-phase power electronic circuits which are non-planar, two methods for planar treatment with three-phase voltage source inverter (VSI) are presented. Based on such equivalent transformation, an improved topology of three-phase flying-capacitor multi-level voltage source inverter (MVSI) is obtained, then a new kind of three-phase MCSI topology is derived from the application of the duality on such MVSI topology. This allows the wealth of existing knowledge relating to modulation of multilevel VSI to be immediately mapped to the multilevel CSI. Analytical results show that the derived MCSI and its corresponding MVSI present dual features such as operations, modulations and control strategies, etc. Some simulation results are given to verify the proposed MCSI structure.