Energy Efficency Investigation of a 3kW DC/DC Converter for Electric Vehicle Applications using Full Wave and Current Doubler Synchronous Rectification

Abstract

The Master's Thesis is devoted to quantify and verify the performance of two full-bridge DC/DC converter topologies that are suitable for usage in a hybrid electric vehicle, whereas possible improvements should be proposed and implemented. The two topologies investigated are the full bridge with full wave rectification and full bridge with current doubler synchronous recti fication. The idea is that the converter topologies should be implemented in Allegro AMS and a loss calculation script should be written in Matlab. It should be possible to simulate and study the converters' performance in the ideal and real cases. In the project two different topologies were investigated and built in Allegro AMS. Simulations have been performed in Allegro AMS and calculations carried out in Matlab. Zero-voltage switching (ZVS) technique has been implemented and verified. A suitable transformer has been designed and the whole procedure has been presented in the report. Losses have been determined and the efficiency plots have been created and presented. The performed simulations have shown that it is possible to utilize both converters in a HEV and the normal performance has been verified. ZVS switching technique has been successfully implemented that has reduced switching losses significantly, which has improved the efficiency of the converters. A calculation script for loss determination has been successfully written and losses have been determined, which are included in the results section. A transformer has been designed and the size of it has been minimized with the appropriate core being chosen. Efficiency has been determined and for the full wave topology it reached a maximum value at 95.4 % at the load level of 35% and for the current doubler it has reached 96.5 % at the load level of 30 %. It has been shown that the current doubler is more efficient than the full wave topology.