Research On Magnetically Coupled Resonant Wireless Power Transfer Technology Of Small Unmanned Aerial Vehicle

Due to their simple operation and low cost,small unmanned aerial vehicles(UAV)have become widely used in various fields,including remote sensing monitoring,emergency rescue and disaster relief,and safety inspections.However,the currently used contact charging method,despite being cost-effective and efficient,has limitations in terms of the charging environment and safety hazards.The wireless power transfer,which provides power to drones without any mechanical connections,offers a safer and more flexible solution for unmanned occasions.The unique shape,small size,and limited carrying capacity of small UAV require a high design standard for the coupling mechanism.Additionally,the charging environment poses challenges such as fluctuating charging currents due to load and coupling parameters changes,which could compromise the reliability of wireless power transfer systems.Therefore,this paper aims to investigate the magnetically coupled resonant wireless power transmission technology for small UAVs,considering aspects such as resonance compensation structure,coupling device design,and system control.The research aims to enable efficient and stable charging of small UAVs,even under small-scale misalignment,resonance parameter offset,and load change.The specific research work includes:First,this paper investigates the theory of magnetic coupled wireless power transfer and applies the clustered parameter circuit method to model the compensation topology and analyze its structural characteristics.Building on this foundation,this paper uses the LCC-S type compensation topology,which ensures a constant current and high efficiency of the transmitting coil,in the wireless power transfer for small UAVs.The expressions of system output current and transmission efficiency are obtained,the influence of load and coupling coefficient changes in system transmission characteristics are analyzed,and then the factors that affect the charging performance of drones in practice.Secondly,based on the characteristics of small UAVs,this article proposes a new type of orthogonal coupling device with a concave emission end.This device is designed by analyzing the magnetic field distribution of transmitters and receivers and optimizing its parameters using the parameter sweep method.Next,build a model of the device’s magnetic field structure and use ANSYS finite element software to simulate and analyze its magnetic field distribution and antioffset capacity.The results demonstrate that the new orthogonal coupling device can better concentrate the magnetic field on the receiving coil,the coupling coefficient is higher,and it has a good ability to resist single-dimensional and multi-dimensional offsetThen,according to the charging reliability requirements of the wireless power transfer system for small UAVs,a bilateral cooperative constant current control strategy based on the model prediction algorithm and gradient descent method is proposed.The secondary side controls the duty cycle of the Buck circuit based on the model prediction algorithm,and the duty cycle and input voltage of the inverter on the primary side is controlled based on the gradient descent method.So that the system improves the transmission efficiency while outputting a constant current.The proposed control strategy is modeled and simulated using MATLAB,and its effectiveness and feasibility are verified.Finally,the experimental wireless power transfer platform for UAVs was designed and tested.The experimental results show that the new orthogonal coupling mechanism proposed at this time has a stronger anti-offset ability than the bipolar coupling mechanism,and can improve the stability of the UAV when it is misplaced.In addition,the proposed bilateral cooperative control can quickly achieve 3A constant current output and improve system efficiency under the load and coupling coefficient change.