Design of bidirectional DC/DC converter for V2G applications
                                         LIU Bo, JING Lei, LI Bodong, WANG Xiaoqing, QIU Maohang, CHEN Min
                                           (School of Electrical Engineering, Zhejiang University, Hangzhou 310027, China)

Abstract: In order to solve the design problem of the bidirectional DC/DC converter applied for the twoway interaction between electric cars and power grids, a full research aiming at the characters of the application, load and the characters of the dual active bridge and resonant CLLC topology was conducted. According to the research about the application environment and the load, a topology achieving soft switching in wide gain range should be chosen for the bidirectional DC/DC converter used for this application. Two topologies, dual active bridge and resonant CLLC, were compared based on the application environment, and the better one, resonant CLLC topology was chosen. Design guideline and key calculation formula were given for the resonant CLLC topology. A 3kW bidirectional DC/DC prototype based on the resonant CLLC topology applied for V2G was designed based on the design guideline. Experimental results indicate that the efficiency of this converter based on Si MOSFETs achieved 96.6% in both forward mode and backward mode, when the switch frequency above 100 kHz.

Key words: grid; electrical vehicle; V2G; bidirectional DC/DC converter