SIMULATION OF BIDIRECTIONAL DC-DC CONVERTERS

Abstract

DC-DC conversion technology is a major subject area in the field of power engineering and drives, and has been under development for six decades. Most of the present day research work is being conducted on unidirectional current flow converters which are the conventional converters. A bidirectional DC-DC converter is gathering much attention these days in the field of automotive industries. Besides this, these converters are also being extensively used in Uninterruptible Power Supplies (UPS) and battery charging systems. Also, these bidirectional converters are presently being employed in advanced electric vehicles such as Hybrid Electric Vehicles (HEVs) and Fuel Cell Electric Vehicles (FCEVs). This thesis presents the simulation of bidirectional DC-DC converters using two methods namely, PI Control and Fuzzy Control. Initially, open loop simulations were performed on Buck-Boost and Flyback bidirectional DC-DC converters and the results have been discussed. Fuzzy rules have been framed for implementing the controller for bidirectional DC-DC converters. Comparative analysis has been made between PI and Fuzzy controllers by considering load variations, source variations and also by changing the reference voltage. Simulations have been performed in MATLAB SIMULINK Version R2008a. The fuzzy logic tool box is used to create and edit fuzzy inference system and SIMULINK is used for simulating the bidirectional DC-DC converter along with its control.