Switching flow graph nonlinear modeling method for multi-state switching converters

Switching converters operating in multi-state switching mode (more than two states) feature multidimensional control over their state variables. In this paper, a large-signal multi-state modeling method is developed based on the switching flow graph method to study the steady-state and dynamic properties of the multi-state switching converters. This modeling method uses graphic presentation to reveal the cause and effect relationship of the dynamics within a multidimensional converter. A three-state buck-boost circuit is conceived with two duty ratios controlling double outputs as an example to test this modeling method. The experimental results confirm the theoretical prediction closely. This multistate switching flow graph modeling method is very general, easy to use, and accurate. It provides deep physical insight for engineering design