Transmission Characteristics Analysis And System Design Of Static Wireless Power Transfer System Based On SAE J2954

The wireless power transmission technology(WPT)can solve the problems such as the large site area of wires and the influence of the extreme weathers in the process of power transmission.The technology has become a research hotspot in the fields of electric vehicle and industrial robot.With the production of the wireless power transmission system,the Society of Automotive Engineers(SAE)announced the first standard J2954 in electric car wireless charging industry.The characteristics analysis and the design of the wireless power transmission system in line with the standard become urgent problems.Firstly,the characteristics of the asymmetric compensation structure of wireless power transmission system based on SAE J2954 are studied on in this paper.According to the mutual inductance coupling theory and the circuit principle,the circuit characteristics and the resonant conditions of the basic resonant cavity are analyzed.The circuit model of the asymmetric compensation structure is established.The formulas of transmission performance are obtained to analyze the no-load characteristic and output power characteristic.The comparison of the design methods between different compensation structures with is finished.The results show that the design method of constant current output of the system with asymmetric compensation structure is relatively simpler.Secondly,the design of the wireless transmission system based on SAE J2954 is carried out.The influences of the primary compensation capacitor and the secondery compensation capacitor on the output current,the power and the efficiency are studied by Matlab simulation.The optimal parameters of the compensation structure are determined to satisfy the technology indexes in SAE J2954.Based on the analysis of the mutual inductance and the materials,the shapes of the magnetic coupling structure and the magnetic shielding device and the winding method of the coil are designed.In addition,the power conversion circuit which matches the resonant compensation is analyzed and selected.The frequency tracking system and protection circuit are designed with consideration of the constant current charging modes.The overall system design is completed.Finally,the simulation model and the test platform of the static power transmission system with asymmetric compensation structure are builted.The simulation and test analysis are carried out.The simulation model is builted by Simulink module.The transmission characteristics of output power and output current are simulated.The tests of the variable load,the variable distance and the frequency tracing are finished and the transmission characteristics are acquired.The results show that when the rating frequency is 85 kHz,the distance is 140 ~ 210 mm and the range of the load is large,the constant current output of the static wireless power transmission system designed in this paper can be realized,the power is not less than 3.7 kVA and the efficiency is not less than 85%.