Adaptive voltage regulation of PWM buck DC-DC converters using backstepping sliding mode control

This paper develops novel methodologies and techniques for voltage-regulation and implementation of a buck DC-DC converter. This type of converter is modeled as a linear averaged state-space system model with an adjustable load. The output voltage and the inductor current are employed to achieve design of an adaptive backstepping sliding mode controller for the buck DC-DC converter. Using singular perturbation method, a reduced order model is derived in order to show that the effect of equivalent series resistance (ESR) of the capacitor can be ignored and the buck DC-DC converter can be well approximated by the reduced order model. Based on the reduced order model, adaptive sliding mode control based on backstepping approach is proposed to control a stand-alone buck DC-DC converter. This proposed control method has been verified by computer simulation and implemented utilizing a stand-alone digital signal processor (DSP) TMS320C542 from Texas Instruments. Experimental results show that the proposed control method is proven to be capable of giving satisfactory voltage regulation performance under input voltage variations and load changes.