Comparison of linear and nonlinear buck converter models with varying compensator gain values for design optimization

Nonlinear phenomena in a closed-loop pulse-width modulated (PWM) buck converter are analyzed. We show three different methods to model the buck converter: a linearized small-signal model, a nonlinear model with a stiff source, and a nonlinear model with a rectified grid source. Using three different compensator gain values that were specifically chosen from a bifurcation diagram, the step responses of the three buck converter models are compared. With the ultimate goal of optimizing the design process of switching converters, the nonlinear dynamics of switching converters is studied using simulation models built in MATLAB/Simulink/PLECS.