Key Technologies Of Lightweight Design Of Electric Vehicle Wireless Charging System

Wireless charging technology has unique advantages such as reliability,strong security,high space utilization and convenience.It is one of important development trends in the field of electric vehicle(EV)charging technology in the future.However,for most of the current designs of wireless charging systems,the lightweight requirement of EVs is not considered,which reduces the driving range and overall efficiency of vehicles,and has an adverse impact on the vehicles’ handling and power.To solve this problem,this thesis studies the key technologies of lightweight receiver design of EV wireless charging system from three aspects:compensation topology and parameter configuration,magnetic coupler design and power electronic conversion.The specific work carried out in this thesis is as follows:1)The basic working principle of wireless charging system for EVs is introduced,and the lightweight potential of existing wireless charging systems is analyzed.Then the structure of high-power wireless charging system adapted to the lightweight requirement is designed,and the mathematical model of parallel modular wireless charging system with LCC-S compensation is also established.2)A compensation parameter configuration method to achieve a lightweight receiver and short-circuit tolerance is proposed.The transmission characteristics,lightweight effect and short-circuit tolerance of the wireless charging system with this method are analyzed,and the design process of the system with detuned receiver is given.The effectiveness of the method is verified by simulation and experiment.3)The effect of coil misalignment on the wireless charging system with the proposed compensation method is studied,and the design criteria of magnetic coupler considering the misalignment are proposed in conjunction with the power and efficiency requirements in practical applications.Two compact magnetic coupler structures are designed and their design processes are given.A magnetic coupler prototype is fabricated and its application effect is tested with the proposed method.4)The feasibility of synchronous rectifier based on gallium nitride power device for receiver side rectification is discussed,and the losses of diode and synchronous rectifiers are analyzed.The control strategy to minimize body-diode conduction and achieve zero voltage switching is proposed.The corresponding hardware circuit is designed and fabricated,and the improvement of synchronous rectification on the efficiency and receiver side volume is verified.