PWM-Based Current-Sensorless Adaptive Sliding-Mode Control for the Boost Converter with Constant Power Load

The boost converter feeding a constant power load (CPL) is a non-minimum phase system that is prone to the destabilizing effects of the negative incremental resistance of the CPL and presents a major challenge in the design of stabilizing controllers. Numerous studies in the design of stabilizing controllers have been proposed with the overwhelming majority of them requiring measurements of the inductor current for their implementation. To the best knowledge of the authors, very few studies in the literature have dealt with current-sensorless control of the DC-DC boost converters with CPL. In this work, a simple adaptive controller that relies only on the output voltage measurements for its design and implementation is introduced. A Luenberger-type observer is developed to estimate the inductor current and the output load power. A linear sliding surface is used to derive the controller that is simple in its design and yet exhibits excellent features in terms of robustness to external disturbances, parameter uncertainties, and parasitics. Also, a simple procedure to select the controller gains is outlined. The robustness of the controller is validated by computer simulations.