Switching Flow-Graph Modeling Technique for Three-Phase Inverters

In this paper, a unified graphical modeling technique is developed for investigating the behavior of pulsewidth- modulated three-phase inverters. By introducing the virtual- switch concept together with its virtual switching function, it is seen that the existing attractive switching flow-graph modeling technique for dc-to-dc converters can be extended to three-phase inverters without losing its merits. The corresponding large- signal, steady-state, and small-signal models can then be also obtained easily. Some examples, implemented easily with MATLAB/ Simulink, are also given to demonstrate the feasibility of the proposed technique.