Small-signal Model for PWM Converters using Extended Describing Function Approach

The application of the Extended Describing Function Method (EDF) to PWM CCM operated converters is proposed in the paper in order to derive the small-signal transfer functions. In order to exemplify the method, two PWM converters have been chosen: a Buck and a Boost topology. In order to validate the obtained results, the models have been compared to the traditional averaged small-signal models and perfect agreement has been achieved.