On the design of nonlinear pulse-width-modulation controllers

Abstract

In this article a design method is proposed for the specification of a variety of Pulse-Width-Modulation (PWM) feedback controllers acting on plants described by Nonlinear Dynamical Systems. It is shown that an average model of the PWM controlled system, derived by an infinte sampling frequency assumption, is simply obtained by replacing the discontinuous FWM controller by a memoryless nonlineariy completely specified by the feedback duty ratio function. The average model captures the essential qualitative stability properties of the controlled system and, thus, can be used to considerably simplify the PWM controller design task. The case of PWM regulators for linear plants can be systematically treated by traditional input-output design methods. Some examples are provided.