A universal fuzzy controller for a non-linear power electronic converter

Abstract

This paper presents the development of a universal fuzzy controller for a non-linear power electronic converter. The classical boost converter used in power supplies is a minimal phase system with a right-half-plane zero. This right-half-plane zero forces the designer to go for controllers that give slow dynamics. The conventional linear PI controllers for such converters, designed under the worst case conditions of maximum load and minimum line conditions, present a lower loop bandwidth even if the operating conditions are better. Moreover, the system response is sluggish. Modern fuzzy controllers, on the other hand, can be designed to adapt to varying operating conditions for application in such nonlinear systems. This paper designs a universal fuzzy controller and compares its performance at various operating points with local PI controllers designed for the particular operating points. The settling time and overshoot for startup and step response obtained by computer simulations have been compared. The superior performance of the fuzzy controller, in particular, its ability to achieve good transient response under different operating conditions is clearly established.