Unmanned Aerial Vehicle Wireless Charging System Based On Orthogonal Magnetic Field Coupling

As a flexible detection equipment,Unmanned Aerial Vehicle(UAV)is widely used in remote sensing monitoring,plant protection,inspection and other aspects.By arranging unattended autonomous charging base stations in the flight route of UAV and adopting wireless charging technology,the requirement of UAV relay autonomous power supply can be met when long-distance mission is carried out,and the flight time of UAV can be effectively extended.Therefore,a lightweight,high-efficiency,fully autonomous wireless charging system for UAV is designed from four aspects: magnetic coupler,an overall circuit of wireless power transmission,overall closed-loop power control,experimental prototype construction and experimental test.According to the characteristics of UAV,such as irregular structure,narrow internal space and limited load,the structure and parameters of magnetic coupling device are designed.An orthogonal magnetic coupling device is proposed,analyzed and optimized.The structure optimization and magnetic field analysis of transmitter and receiver are carried out respectively.The optimal coupling coefficient is found by parameter scanning method,and the size parameters of the orthogonal magnetic coupling device are optimized based on the principle of coupling efficiency enhancement and lightweight of the receiving side.Based on ANSYS Maxwell finite element tool,the simulation model of orthogonal magnetic coupling device is established and the magnetic field distribution characteristics are analyzed.The physical model of the orthogonal magnetic coupling device is built,and the dislocation tolerance is analyzed based on the impedance analysis method.In order to lighten the receiver and improve the charging efficiency,the topology design and analysis of the system circuit suitable for UAV wireless charging are carried out.The compensation topology of different combinations is modeled and analyzed,and the compensation structure suitable for UAV wireless charging is obtained by comprehensive comparative analysis of output characteristics,complexity,economy and other factors.The full bridge inverter circuit and single-phase bridge semi controlled rectifier circuit are designed and analyzed,and the output mathematical model is established.The circuit of the radio power transmission system is integrated,and the mathematical description of the output voltage and current of the system is established.The small signal modeling of the system circuit is analyzed,and the stability performance of the system at each frequency is analyzed.The simulation model of the system circuit is built in PSpice,and the corresponding circuit parameters under different dislocations are set to test the stability of the system circuit and verify the accuracy of the circuit model.In order to achieve high-efficiency constant current / constant voltage closed-loop charging in the process of battery charging,the research on system power control is carried out,and a bilateral cooperative closed-loop power control strategy is proposed.Theoretical analysis of the maximum efficiency tracking of semi controlled rectifier circuit based on impedance matching technology is carried out.The synchronous phase control method of the secondary half controlled rectifier circuit is analyzed and designed.The simulation model of the control signal circuit is built by Multisim to verify the feasibility of the synchronous phase control method.The overall control topology scheme of the original secondary side wireless communication system is designed,and the bilateral cooperative power control technology is used to make the system charge in constant current / constant voltage closed-loop and realize the maximum efficiency tracking in the charging process.The system circuit closed-loop control simulation model is built by MATLAB to verify the rationality and feasibility of the power control scheme.In order to verify the scheme of the system designed in this paper,an experimental prototype and an automatic UAV wireless charging station are built and tested.The hardware circuit is designed and made.The open-loop test is carried out,including dislocation,load change and phase shift angle change.Constant current / constant voltage closed-loop experiments are carried out by using bilateral cooperative power control,and 10 S lithium battery charging experiments were carried out.The outdoor charging test of fully automated UAV wireless charging station is carried out.The test results show that the system has a certain capacity of dislocation tolerance,the maximum output power of the system is 380 W,and the overall efficiency is 90.374%.The maximum output power of the system is 126.42 W,and the overall efficiency is87.955%.Compared with the original side power control,the system efficiency is significantly improved.The fully automatic wireless charging station of UAV proposed in this paper can realize efficient autonomous charging when UAV lands at any position of charging platform in an outdoor environment without human intervention.