Abstract: In order to improve the efficiency of Buck converter in electric vehicle wireles power transfer(EV-WPT) system and further the overall efficiency of the whole system,a piecewise linear state space model with parasitic parameters and switching process were established based on the original two simplified models,which was closer to the actual non-ideal Buck converter.Based on the stroboscopic mapping and phase trajectory theory,the steady-state working points of the three models were analyzed and compared by simulation.Finally,based on the non-ideal model,the efficiency optimization of the Buck converter was realized.

Key words: electric vehicle wireles power transfer(EV-WPT), buck converter, efficiency optimization, stroboscopic mapping, phase trajectory