Control of PWM inverter using a discrete-time sliding mode controller

PWM inverters are widely used in UPS systems and driving induction motors. They give AC sinusoidal voltage under linear or nonlinear loads which is a basic tracking control problem. Since the duty cycle of a PWM inverter is unchanged within one switching period, inverters are very suitable to be represented by discrete-time state equations. A discrete-time sliding-mode controller based on an improved reaching condition has been proposed by Gao et. al. This paper applies this controller to control PWM inverters with linear and nonlinear loads. It is shown that good output responses are obtained in both cases.