Global Analysis Of Wpt System Based On Triple Subdivision Cell-to-cell Mapping Method

Wireless Power Transfer(WPT)technology receives increasingly attention by the community because of its convenience,flexibility,security and other advantages.The rapid development of science and technology has brought the WPT technology new opportunities and challenges.Soft-switching,as an effective way to improve the transmission performance,is widely applied to the WPT system.At the same time,the existence of multiple soft-switching phenomenon makes the behavior of the WPT system complex and affects transmission power and efficiency on the contrary,which has an adverse effect on the parameter design and control optimization of the WPT system.The existing research results focus on the resonance point of the WPT system and the influence of parameter changes on the resonance point,and the global characteristics such as the domain of attraction corresponding to the resonance point are less analyzed.In this paper,based on the analysis of global characteristics of the WPT system,a triple subdivision cell-to-cell mapping method is proposed based on cell-to-cell mapping theory.This method subdivides each dimension of the cell space into three parts in each iteration and the cells containing the attractors and domains of attraction are subdivided step by step and relatively clear attractors and domains of attraction are obtained quickly and effectively.The improved method effectively reduces the amount of computation and a reasonable accuracy of the analysis result can be reached in a few iterations.As a result,Different mapping methods are given for the equilibrium point and limit cycle in the meanwhile.In this paper,the improved method is applied to analyze the global characteristics of the WPT system to represent a clear demonstration of the mechanism behind the complex phenomenon of the WPT system,present the complex characteristics of the WPT system comprehensively,intuitively and in detail,and provide some reference value for the academic research and engineering realization of the WPT technology.Firstly,the basic idea,concepts and algorithm realization of cell-to-cell mapping method are described in detail,and the flow chart of the algorithm is given.Take the Duffing system as an example to verify the validity and disadvantages of the cell-to-cell mapping method.Secondly,in view of the insufficiencies of cell-to-cell mapping method,a triple subdivision cell-to-cell mapping method is proposed.And the basic idea and program realization are illustrated in turn,the algorithm flow charts of the main function and the key sub-function are given.Take the same Duffing system as an example,comparison analysis shows the effectiveness and the advantages of the triple subdivision cell-to-cell mapping method.Then,taking LCL circuit as the research object,the state space model is established,the possible types of attractors are analyzed and different mapping schemes are given.The triple subdivision cell-to-cell mapping method is used to solve two equilibrium points and a limit cycle of the LCL circuit,and the spatial position of attractors and domains of attraction are clearly presented.Simulation results verified the correctness of attractors and domains of attraction,and the validity of the triple subdivision cell-to-cell mapping method is further verified.Finally,taking the parallel-parallel WPT system as the research object,the triple subdivision cell-to-cell mapping method is applied to obtain two resonant points in the system.The domains of attraction of the system on the Poincare section are obtained.MATLAB/Simulink simulation results verified the correctness of the results obtained by the method,and the validity of the triple subdivision cell-to-cell mapping method in the global characteristic analysis of the parallel-parallel WPT system was verified in the meanwhile.