Switching flow-graph nonlinear model of active power filters

In this paper a large signal model is developed based on the switching flow-graph method to study the steady-state and dynamic response of three-phase active power filters (APF). This method translates switching converters directly to graphic dynamic large signal models and uses graphic representation to reveal the causes and effect relationship of the dynamics within an APF. Three-phase APF circuits with one-cycle control are used to test this modeling method. APF switching flow-graph is general, easy to use, and accurate. It provides deep physical insight for engineering design and dynamic analysis of active power filters.