A Modified PI-Controller Based High Current Density DC–DC Converter for EV Charging Applications

Abstract: In this project, a DC-DC converter with a modified PI controller has been presented which helps to achieve the required output voltage and high current density with negligible overshoot for the specified lithium-ion battery system to minimize the charging time. Apart from minimizing the power loss of the active switches, the proposed system minimizes the junction temperature eventually improving the life cycle of the converter. The analysis of the proposed converter is performed both in ideal and non-ideal conditions. The power loss of the active switches and the junction temperature have also been analyzed. An effective and economical dc and ac side inductors have been designed and analyzed the performance of total power loss and temperature rise. The results show that the proposed converter can maintain a power factor around 90% and a total harmonic distortion around 0.46%, which is ideal for the high-density load current. The reliability of the dc-dc converter is also evaluated. A hardware prototype has also been implemented to confirm its viability for EV battery charging applications. The simulation results can be evaluated by using Matlab/Simulink Software.

Keywords: Buck, lithium-ion battery charger, electric vehicle battery charger, ac-dc converter, isolated ac-dc converter, power factor correction, MOSFET power loss estimation, MOSFET thermal analysis, modified PI controller, state-space representation of converter.