Nonlinear Control of a Buck Converter Which Feeds a Constant Power Load

In this paper, a nonlinear control strategy for controlling a dc/dc buck converter feeding a constant power load is proposed. The main objective of the proposed controller is to improve the transient performance when in presence of unknown power disturbances. A feedback controller is combined with a feedforward strategy. A nonlinear reduced order observer is used for estimating the value of the power load and its time derivative. These estimated values are fed forward to the nonlinear feedback controller whose design is based on feedback linearization method. The proposed controller is tested via simulation and experimental results.