The Fringing Electric Field Suppression Method Of ECPT System With A Double-sided LC Network

Electric-field coupled power transfer(ECPT)technology takes high frequency alternating electric field as an energy medium to transfer power from the grid or power source to load wirelessly,making the electrical equipment break away from the cable.It's advantages include light weight,variable shape,power transfer capability through metal barriers,no eddy current losses in the metals nearby the system and so on.Therefore,ECPT technology and magnetic coupling wireless power transfer(MC_WPT)technology can form complementary advantages and develop together.However,as the transmission power and distance of ECPT systems incerease,the plate voltage of the coupler will also increase,which not only brings electric shock hazard to the surrounding organisms,but also causes potential safety hazards such as the radiation of the fringing electric field.In order to further promote the development of ECPT technology,the above security problems need to be solved urgently.This paper mainly focuses on the fringing electric field suppression of the ECPT system.Based on Ansoft Maxwell,the capacitive coupler is modeled,the influence of system operating frequency,plate material,plate thickness,plate shape,plate coupling mode,transfer distance,plate voltage and phase on the fringing electric field distribution is analyzed.The distribution laws of fringing electric field around the capacitive coupler are also given.On this basis,a novel four-plate capacitive coupler is adopted to effectively suppress the fringing electric field by reducing the voltage of the outer plates.In order to study the most serious radiation of fringing electric field,the model of the system is established by taking the ECPT system with double-sided LC compensation network which is easy to realize high-power and long-distance transmission as an example.The formulas of the four coupling plates voltage are derived.Moreover,the main affecting factors of the voltage on the outer plates and the structural advantages of the novel four-plate capacitive coupler are discussed.Considering the transfer power,efficiency and power factor of the system,a design method of system parameters and the coupler is proposed to suppress the fringing electric field.Finally,the system simulation model is established in MATLAB/Simulink and Ansoft Maxwell software.According to the proposed capacitive coupler and system parameters design method,the equivalent model of the four-plate coupler,the calculation method of the plate voltage and the power factor are verified through simulation model.The distribution of the leakage electric field around the capacitive coupler is simulated.The results show that the leakage electric field is suppressed effectively,meeting the requirements of the system.Subsequently,based on the previous theory and simulation analysis,a experimental device with power of about 50 W and efficiency of about 86% is set up.In the meanwhile,the transmission performance and the suppression effect for fringing electric field of the system are measured and analyzed.The experimental results are consistent with the theoretical and simulation values,which proves the effectiveness and feasibility of the proposed capacitive coupler and system parameters design method for fringing electric field suppression.