An Improved current sharing method for paralleled DC/DC converter using fuzzy logic control

Abstract

This paper introduces a new fuzzy logic control application, associated mathematical theory and the concept and its advantages through comparative simulation with existing classical methods. A stable fuzzy logic controller for the master-slave current sharing loop of a paralleled DC-DC system is presented that exhibits a considerably improved large signal performance over the presently employed small signal designed compensators. Because of high system complexity, the present small signal designs are unable to give a good response for large load changes and line transients. Fuzzy logic, by dealing naturally with nonlinearities, offers a superior controller type for this type of applications. The design uses a type-2 compensator to derive the fuzzy inference rules, and simulation results show a good parameter insensitive transient response over a wide range load-step responses, e.g., from 25% to 50% of the nominal load. Current sharing control is formulated as a tracking problem.