Self-Scheduled Fuzzy Control of PWM DC-DC Converters

Abstract

This work proposes a Self-Scheduled Fuzzy Control (SSFC) of PWM DC-DC Converters. The main difficulty in controlling these systems stems from their non linear nature as their switched circuit topology entails different modes of operation. Based on the Takagi-Sugeno Fuzzy Modelling approach with the duty ratio as premise variable, the converter model can be derived in every operating point. For each local model, a state feedback based control law is designed by the way of the PDC (Parallel Distributed Compensation) and LQR (Linear Quadratic Regulator) techniques. The nonlinear feature of the transfer function relating the output voltage to the duty ratio, caused by the inductor ESR, is handled by a Piece wise Affine (PWA) approximation using TS method of fuzzy inference. Finally, simulation results from a PWM Buck-Boost converter illustrate the efficiency of the proposed approach.