| The thesis addresses comprehensively the issue of how to improve the performance of DC-DC Converters using Fuzzy Logic Control.; In this thesis, the triangular membership function has been considered for Fuzzy Logic Control of DC-DC converters. By changing the slope of the triangular membership function, its influence on the performance of the converters is studied using simulations. The simulations show that, to fuzzify the change of error, increasing the slope of the triangular membership functions can significantly reduce the initial current of the controlled converters. In the defuzzification procedure, increasing the slope of the triangular membership functions can slightly lessen the initial current. Increasing the slopes of both the membership functions to fuzzify the change of error and to defuzzify the change of duty ratio (output) can further improve the starting performance of the converter. But increasing the slope of membership functions to fuzzify error shows worse performance.; This thesis also presents a comparative study of different defuzzification methods adopted to Fuzzy Logic Control (FLC), for application to DC-DC Buck Converters, such as Center of Area (COA), Center of Sums (COS), Height Method (HM), Middle of Maxima (MOM), Center of Largest Area (COLA), and First of Maxima (FM). (Abstract shortened by UMI.)... |
