Research On Wireless Charging Technology Of Electric Inspection Smart Car Based On Hybrid Self-Switching Resonant

With the rapid development of economy and technology in China,the power consumption of the whole society is also increasing,so the transmission line plays an indispensable role in energy supply.In order to ensure the safe and stable operation of the power system,it is necessary to inspect the transmission line regularly.Therefore,the inspection smart car came into being.However,for the transmission line inspection in complex environment,it is essential to ensure the accuracy of inspection and improve the efficiency of inspection,so as to achieve full automation.This is a great challenge to the endurance of the car.But the traditional contact charging scheme has many problems,such as frequent plugging and aging,electric shock in humid environment and so on,which is not suitable for the Full-Automatic Fine Inspection Solution.While the existing wireless charging scheme can make the charging device occupy a small space,fast charging,and there is no direct electrical connection interface with the charging equipment,and it has been widely used in life.Based on this,this article studies the wireless charging technology of inspection smart car based on Magnetically Coupled Resonant Wireless Power Transfer(MCR-WPT).In order to realize the constant current and constant voltage charging of smart car,this article analyzes and designs some key problems in the charging technology.The main research contents include the following four aspects:(1)This article introduces wireless charging technology at present,and explains their transmission principle and application scope.The research status and working principle of Magnetic Coupling Resonant Wireless Charging Technology were introduced in detail.Three key technologies,including coil structure optimization,resonant topology and solution to realize constant current and constant voltage charging were described in detail.(2)Aiming at the problem that the structure and anti-offset of transmitting coil and receiving coil in wireless charging system will change the distribution of magnetic field,which will reduce the transmission efficiency and power of charging system,this article proposes a planar disc beam splitting variable turn structure coil,and optimizes the design of parameters of the coil.The transmission characteristics and anti-offset characteristics of the structure were compared and verified by modeling and simulation.The experimental results show that the designed coil structure has better transmission ability and anti-offset ability.(3)In order to reduce the number of switching devices and passive components in the resonant wireless charging system,improving the transmission efficiency of the charging system,and simplifing the control strategy of the primary and secondary sides,a hybrid selfswitching resonant topology based on LCL-LCL/S was proposed,which can realize the smooth switching of constant current and constant voltage through the self-switching operation of its own structure.Then,according to the characteristics of battery charging curve,resonant current threshold and voltage jump threshold,a parameter optimization design method suitable for hybrid resonant topology network was further introduced to avoid the limitation of parameter empirical selection.(4)Finally,the experimental platform was built,the high frequency inverter,rectifier and switching circuit were designed,and the corresponding algorithm program was written.The Zero Phase Angle characteristics,constant current and constant voltage output characteristics and constant current constant voltage switching characteristics of the wireless charging system were verified by experiments.It shows the correctness of the theoretical analysis and the feasibility of the scheme design.