Research On Key Problems Of UAV Wireless Charging System Based On Magnetic Coupled Resonance

Unmanned Aerial Vehicles(UAVs)have significant advantages such as flexible operation,easy to take off & landing,and strong environmental adaptability.They are widely used in military confrontation,disaster relief,safety inspection,photography& video recording,agricultural plant protection,logistics and transportation,etc.UAVs can be basically divided into two types: large high-altitude UAVs and small &mid-size low-altitude UAVs.Large high-altitude UAVs are mainly used in the military field,while small and mid-size low-altitude UAVs are mainly for civil use.At present,the endurance time of civil small and mid-size UAVs is generally short,and the traditional manual battery supply method limits the technical potential of the UAVs.In order to solve the above problem,this paper proposes a solution strategy of UAV wireless power transmission based on the magnetic coupled resonance,and constructs a wireless power supply mode of UAV+ wireless power supply base station to achieve efficient and fast charging.The main research results of this paper are as follows:a)In order to improve the transmission efficiency and optimize the output power of the UAV wireless charging system,a multiple transmitters magnetic coupled resonance wireless power transmission method is proposed.Firstly,the circuit models of single transmitter and multiple transmitters system are built.Secondly,the expression of the relationship between the transmission performance of wireless charging system and multiple parameters of the system is constructed.Finally,based on the relationship expression,the maximum value derivation method is used to obtain the optimal coupling coefficient and load resistance.The theoretical analysis and simulation verification show that multiple transmitters magnetic coupled resonance wireless power transmission method has higher transmission efficiency,greater output power and wider transmission area than the traditional single transmitter magnetic coupled resonance wireless power transmission.b)A directional constant voltage output method is proposed to solve the coil offset problem during UAV wireless charging.Firstly,the theoretical relationship between the output performance and axial displacement,radial displacement,and deflection angle is established at the single transmitter level.Then,the relational expression is extended to the multiple transmitters level.The theoretical relation between the multiple transmitters system's transmission characteristics andparameters is obtained.Finally,the directional constant voltage output adjustment mechanism of the transmitting coil center distance,the axial distance of the transmitting & receiving coil and the load resistance is determined.The simulation results show the effectiveness of the proposed directional constant voltage output method.c)According to UAV's magnetic coupled resonance wireless charging strategy proposed in this paper,a wireless charging system experimental platform including power transmitter,electromagnetic coupled mechanism and power receiver is constructed.The effectiveness of the proposed directional constant voltage output method was verified on the experimental platform.In addition,the influence of the the power transmitter material on the power transmission performance was analyzed on the experimental platform.The choice of non-metallic materials for power transmitter materials is determined.