Research On Long-Distance Inductively Coupled Wireless Power Transfer Technology

Wireless power transfer is an emerging trend in power electronics in recent years,aiming to replace traditional wired energy transmission with wireless energy transmission.Compared with the traditional wired method,the wireless power transfer technology brings more convenience,security and better environmental adaptability,and is more and more accepted.As a novel transmission technology,wireless power transfer uses the primary and secondary side coupled to transmit energy.Coupled radio wireless power transfer is divided into inductively coupled power transfer and electric field coupled power transfer.Among them,the electric field coupled power transfer is still in its infancy,with a short transmission distance and small transmission power.The inductively coupled power transfer is relatively mature,and it is a widely accepted wireless power transfer technology solution,with its structure simple and easy to implement.The traditional inductively coupled power transfer can transmit at a distance of less than 150 mm,and the application is limited,and it can no longer work under longer transmission conditions,which greatly limits the application of inductively coupled power transfer.Based on this,this paper proposes a long-distance inductively coupled power transfer technology,which increases the transmission distance to 400 mm,greatly improving the application of inductively coupled power transfer technology.In this paper,starting from the loosely coupled transformer,unlike the traditional tightly coupled transformer,the inductively coupled power transfer uses a loosely coupled transformer as the transmission carrier.The loosely coupled transformer was modeled and analyzed,and the parameters of the loosely coupled transformer were optimized by a large number of finite element simulation analysis to ensure the overall performance of the system under long-distance transmission conditions.In the aspect of compensation circuit,this paper adopts a high-order compensation of LCC/S based on T circuit,and focuses on comparing the topological adaptability of LCC/S high-order compensation under long-distance transmission conditions.The fundamental analysis method is used to study the characteristics of the topology,and the capacitance voltage stress of the compensation topology under long-distance conditions is analyzed.In addition,the maximum efficiency point analysis and impedance matching techniques for systems under long-distance conditions are also proposed.In the latter stage of the system,this paper uses a Sepic converter that is more suitable for long-distance power transfer.The small signal modeling is carried out by state space Averaging method,and a suitable PID controller is designed according to this to ensure the system output is stable.Finally,based on the above analysis.The experiment built a prototype with a transmission distance of 400 mm and a power of 100 W,which verified the feasibility of the design.