Application of sliding-mode control to the design of a buck-based sinusoidal generator

This paper is devoted to the design of a sliding-mode control scheme for a buck-based inverter, with programmable amplitude, frequency, and dc offset, with no external sinusoidal reference required. A general procedure for ob taining an autonomous (time independent) switching surface from a time-depe ndent one is presented, For this surface, the system exhibits a zeroth-orde r dynamics in sliding motion. On the other hand, from the sliding-domain an alysis, a set of design restrictions is established in terms of the inverte r output filter Bode diagram and the output signal parameters (amplitude, f requency and dc offset), facilitating the subsequent design procedure. The control scheme is robust with respect to both power-stage parameter variati ons and external disturbances and can be implemented by means of convention al electronic circuitry, Simulations and experimental results for both reac tive and nonlinear loads are presented.