Misalignment Tolerance Design Of Magnetic Coupling Mechanism For Fixed-wing UAV Wireless Charging

In recent years,Wireless Power Transfer（WPT）,which has the advantages of application flexibility,electrical isolation and environmental adaptability,has been widely used in many fields such as electric vehicles,wireless charging for cell phones and biomedical implants,driven by multiple forces such as economic development,scientific research and market demand.However,in the process of electric energy transfer,it still faces problems such as poor adaptation of magnetic coupling mechanism offset,poor system stability,and unstable energy transfer efficiency.Based on the application requirements of wireless charging for fixed-wing UAVs,this paper charging system for requirements of misalignment tolerance.First,based on the charging characteristics of the fixed-wing UAV lithium battery and the space limitation of the nacelle,we adopt an LCC/S-type high-order compensation circuit based on the T-type circuit model of the loosely coupled transformer to achieve constant voltage output and light weight of the secondary side,and give a circuit parameter design scheme to realize ZVS soft switching.The characteristics of the input impedance and output voltage gain of the LCC/S-type compensation circuit are derived using fundamental wave analysis,and harmonic analysis is performed on the circuit to improve the theoretical support for applying the LCC/S-type compensation circuit.Secondly,based on the demand of the fixed-wing UAV for the size limit of the magnetic coupling mechanism and the ability of misalignment tolerance,the finite element analysis method is used to analyze the performance of the magnetic coupling mechanism of the symmetrical circular,square and DD coils.Theoretical analysis and simulation demonstration are carried out on the parameters of various asymmetric magnetic coupling mechanism coils such as shape structure,number of winding turns and mutual inductance,and an optimal design method of asymmetric three-coil magnetic coupling mechanism is proposed.Finally,this paper designs and builds a wireless energy transmission platform based on an LCC/S-type compensation circuit and an asymmetric three-coil magnetic coupling mechanism,and carries out experimental studies.The platform is capable of transmitting 500 W of power wirelessly with a transmission efficiency of over 80%.The experimental results verify that the designed asymmetrical three-coil magnetic coupling mechanism can transmit power with a drop of no more than 10% when the secondary coil deviates by 1/2 of its distance.