Voltage-Mode Fuzzy Logic Controller for Enhancing Synchronous Buck Converter Operation

A synchronous buck converter has been massively applied to decrease the DC voltage level. This topology involves an additional active switch on the low side to replace the diode. As a result, both switches are controlled by each signal in opposite directions. An appropriate control strategy is necessary for the synchronous buck converter to regulate the output voltage according to the desired reference. In this case, voltage mode control (VMC) based on the fuzzy logic algorithm can be employed, eliminating the need for complex mathematical models. One crucial step in achieving optimal results is determining the membership functions of the fuzzy logic controller (FLC). Hence, evaluating suitable membership functions becomes essential to optimize the synchronous buck converter performance. This study presents the VMC based on fuzzy logic for the synchronous buck converter, with varying membership functions of FLC, consisting of Triangular, Trapezoidal, Gaussian, and Generalized Bell (GBell). MATLAB/Simulink is used to verify this work by applying component specifications from relevant datasheets, aiming to represent the general hardware closely. The results show that a good deal of converter output voltage can be achieved by applying Triangular, Trapezoidal, and GBell membership functions. In dynamic tests, the converter performs best when adopting the Triangular method, as indicated by smaller values for overshoot, rising time, and steady-state compared to other membership functions. Then, the efficiency of the synchronous buck converter ranked from highest to lowest, is as follows: Triangular, Gaussian, GBell, and Trapezoidal membership functions.