Feedback Control of Linear Continuous Systems by Pulse-Width Modulation

In this paper, we study pulse-width modulated (PWM) control systems without assuming an arbitrarily high switching frequency. Although we restrict our investigation to linear continuous open-loop dynamics, the PWM process introduces significant nonliearities into the corresponding sampled-data models. Both single-rate and multirate approaches to PWM control are considered, and the latter type of control is shown to be more useful from the point of view of establishing desired equilibrium points. Conditions are found under which the sampled-data models are feedback linearizable, and design techniques are described which can achieve asymptotic regulation or tracking, using either state or output feedback.