Research On The Efficiency Of Wireless Charging Systems For Drones And Their Coil Design

Drones are developing rapidly and are widely used for crop health status inspection and power inspection,but range issues and accurate landing are important obstacles that have been limiting the further development of drones.However,with the introduction of wireless charging,the flexible charging method meets the long-time aerial operation of UAVs and effectively extends the aerial flight time of UAVs.Therefore,this paper develops the following research from four aspects: concave coupling structure design,compensation circuit research,overall closed-loop power control of the system,and experimental platform construction and testing.The structural and parametric design of the magnetic coupling device is carried out for the special fuselage structure of the UAV,the narrow space in the abdomen position and the restricted load,etc.A concave coupling structure is proposed,and the structure is analyzed and optimized.Detailed calculations of the important parameters of the coupling structure(equivalent resistance,self-inductance,mutual inductance,etc.)are carried out separately,and the magnetic field generated in the concave structure is simulated in ANSYS-Maxwell simulation software;under the condition of minimizing the volume of the receiver end,the optimum coupling coefficient of the coupling structure is searched for using the parameter scanning method,the concave coupling device is constructed,and its actual charging process is The tolerant misalignment capability is analyzed.The basic working principle of magnetically coupled resonant type in wireless energy transmission systems is briefly analyzed.To improve the transmission efficiency of the system,a mathematical model of the bilateral inductor-capacitor-capacitor(Double-LCC,DLCC)compensation topology used is established through the analysis of various factors such as output characteristics and anti-deflection characteristics,and the original secondary side inductance ratio is optimally designed and analyzed;the circuit of the wireless energy transmission system is integrated,and the mathematical description expressions of the system output voltage and current are established;afterward,the output power and transmission efficiency of the DLCC asymmetric compensation topology are theoretically analyzed in the system.To meet the demand for high-efficiency constant-voltage/constant-current closed-loop charging of Li-ion batteries,the output power control of the system is investigated,and the overall closed-loop control scheme of the system with primary and secondary wireless communication is analyzed and designed.The circuit simulation model is built in MatlabSimulink to verify the rationality and feasibility of the scheme,and the charging control scheme of the constant-current first and constant-voltage second is realized,and the maximum charging efficiency of the system is ensured.To verify the feasibility of the system designed in this paper,the system charging platform was built and tested.The results show a distance of 10 cm from the left and right ends of the charge in the aligned state,the system can achieve an output power of 960 W,an efficiency of 85.7%,a closed-loop control of charging with a constant voltage of 48 V and a constant current of 20 A,a small size,a lightweight(290g),an easy installation and a strong resistance to offset at the receiving end.