Research On Wireless Power Transfer System Based On LCC-S Wide Coupling Coefficient Range

In recent years,Wireless Power Transfer（WPT）technology has been rapidly developing,which has the advantages of safety,reliability,and easy of maintenance,therefore has received great attention in various fields,with technology becoming more standardized and commercialized.However,in the WPT system,the change of coil relative position is particularly sensitive to the transmission characteristics of the system.The purpose of this paper is to design and research WPT technology with anti-coupling coefficient fluctuation for the case of changing the horizontal relative position of transmitting and receiving coils.Firstly,this paper introduces the working principle of magnetically coupled resonant（MCR-WPT）wireless power transfer system and analyzes the output power characteristics of four common topologies with varying coupling coefficients.In this paper,selects the composite topology LCC-S with high design freedom as the research object and deduces the output characteristics relationship of this topology in detail.Then,based on the traditional single transmitting coil LCC-S topology,the design is optimized and the compensated resonant coil is used as the transmitting coil to form a double decoupled integrated coil,the equivalent circuit model is established using AC impedance analysis,the equation of the system output characteristics when the coil is offset is derived,and the feasibility of the topology theory is verified with the help of MATLAB.Secondly,the design of the coupled coil in the wireless power transfer system with wide coupling coefficients is studied and analyzed.With the help of the finite element analysis software Maxwell,a parametric scan modeling method is used to analyze the self-inductance,mutual inductance,and magnetic induction intensity trends of the coil under different coil structures with longitudinal and transverse offsets,and the effect of adding ferrite cores on the coil.And at the end,the dual decoupled integrated three-coil finite element transient model established in Maxwell software is imported into Simplorer software to realize the joint simulation of multi-physics fields and observe the magnetic field variation of each coil at different moments.Finally,to verify the correctness of the proposed topology,a wireless power transfer system is built and analyzed.The experiments show that under the working conditions of 70mm longitudinal distance between transmitting and receiving coil,0-60mm horizontal and receiving coil,0.35-0.25 variation of coupling coefficient K₁₂ and 0.24-0.15 variation of K_f2,a relatively stable output power of 120W-100W is achieved,and the system structure can withstand short-circuit faults and open-circuit faults with strong robustness.