Research On Output Stability Of Current-fed IPT System Under Variable Load

IPT(Inductive power transfer)technology has become an increasingly popular power supply because of it's safety,flexibility and adaptability to the environment,among them,the stability of output as an important performance index of IPT system is also an important research direction of domestic and foreign scholars.In this paper,aiming at the stability of the output voltage of the current-fed IPT system,based on the constant-transimpedance characteristics of the primary side control method is proposed.Taking current-fed IPT system with parallel parallel(PP)parallel series(PS)and compensation as an object,by building and analyzing the mutual inductance equivalent circuit,had the characteristics of constant-transimpedance under certain working conditions are derivated.Next,the efficiency characteristics of two compensation resonant network are analyzed,optimization of resonant network parameters make the system constant-transimpedance frequency for the efficiency of the optimal frequency,at the same time,the efficiency of the two compensation resonant network are compared under certain parameters,it provides the basis for the selection of the compensation mode and the design of the resonant network parameters.Optimization contactless transformer which is the important part of IPT system,two methods for calculating the inductance parameters of the contactless transformer are presented,the validity of the two methods is verified by experiments.Based on the new calculation method,the influence of the related parameters on the inductance of the contactless transformer is studied.The new control method needs to maintain the constant input bus current,therefore the constant-current control system is added in the traditional current-fed IPT topology,and the principle of constant-current control is described.Based on the above theoretical analysis,this paper presents a new method of IPT system design,which is based on the new control method and the parameter calculation method of the contactless transformer.Finally,The modeling and Simulation of PP and PS compensation system based on the proposed method in cadence software,and the prototype is designed.The simulation results and the experimental results are in good agreement with the theoretical analysis,the correctness and effectiveness of the proposed control methodand parameter design method are illustrated.