On applying graph theory toward a unified analysis of three-phase PWM inverter topologies

In order to provide a comprehensive and unified analysis of the three-phase pulse-width modulated (PWM) inverter topologies, basic considerations from graph theory are applied. This process leads to the establishment of the principle of duality of voltage source inverter (VSI) and current source inverter (CSI) topologies. The switch realization in both converters is presented. The operating switching states associated with the VSI are generated. Tree structures are identified. Although these networks are switching and nonlinear, all the graphs of the acceptable VSI switching states are planar, and therefore duality theory is used to obtain the equivalent switching states between the VSI and the CSI. Finally, mathematical information, namely space vector analysis for both topologies is provided