Research On Resonance Mechanism Modeling, Analysis And Design Methodology Of Magnetic Coupling Wireless Power Transfer Systems

Magnetic coupling wireless power transfer(MC-WPT)technology integrates multiple disciplines,including electromagnetism,power electronics,control technology,physics,materials science and information technology,to realize the transmission of power from the power supply to the electrical equipment without any electrical connection.This technology completely eliminates the restraint of wire and has the advantages of flexibility,safety,reliability and so on.It is very suitable for the power supply of mobile or rotating equipment or the electrical equipment in special environment,such as underwater and coal mines,and has important academic research value and broad market prospects.The contradiction between energy efficiency and space capability of MC-WPT system is the bottleneck restricting the popularization and application of this technology.Technology-based optimization methods are the most common methods to deal with this bottleneck,including system topology design,parameter optimization and corresponding control technology.However,due to the incomplete understanding of resonance mechanism and the lack of accurate mathematic description of the resonant points and related characteristic of MC-WPT systems,these technology-based methods are not effective in improving the energy efficiency and space capability,and it is difficult to achieve global optimization.Ensuring that MC-WPT systems work in resonant state is the basis for improving the energy efficiency and space capability,which relies on the construction of operating mechanism and resonant mode design criteria.Aiming at constructing a systematic operating mechanism and resonant mode design criteria to ensure that MC-WPT systems work in resonant state,this paper focus on the analysis of resonance mechanism and the construction of resonant mode design criteria.The main research work and contributions of the thesis are as follows:(1)A complete modeling and analysis method based on modal analysis is proposed,which suits for arbitrary coil MC-WPT systems.Aiming at the problems that the traditional modeling and analysis methods of MC-WPT systems cannot fully reveal the resonance mechanism and construct the general mathematic description of resonant points of MC-WPT systems,based on the fact that the MC-WPT system is a kind of multi-degree-of-freedom electromagnetic oscillating system composed of multiple oscillating circuits,a systematic modeling and analysis method based on modal theory is proposed.With the proposed method,the analytical current responses of arbitrary coil MC-WPT systems can be quickly and accurately determined.It lays a theoretical foundation for the subsequent mechanism analysis and design criteria construction of resonant mode.(2)The resonance mechanism of MC-WPT systems is derived and a systematic operating mechanism is established for MC-WPT systems to operate at resonant state.Aiming at the problem of low energy efficiency and space capacity caused by MC-WPT systems operating at non-resonant state,based on the established system model and the relevant definitions in vibration,the modal parameters and the mathematic relationship between modal parameters and energy efficiency of MC-WPT systems are derived.Then the evolution of resonant mode of MC-WPT systems is analyzed with the modal parameters as the trajectory,based on which the analytical expressions of the resonant frequencies and corresponding energy efficiency are derived,the resonance mechanism and distribution characteristic of resonant points are revealed and then a systematic operating mechanism to keep MC-WPT systems in resonant state is established.(3)The principle of modal parameters configuration based on spectrum indexes is proposed.In view of the lack of corresponding resonant mode design criteria to make MC-WPT systems resonate at given bands,by quantifying the relationship of system spectrum indexes and modal parameters,the resonant mode design is transformed into two parts: modal parameters configuration and actual modal parameters design.On the basis of the established system model and analytical expressions of resonant points,the mathematic relationship between the spectrum indexes and modal parameters of MC-WPT systems is established by deeply analyzing the spectrum characteristic of MC-WPT systems.Then according to the mathematic relationship,a set of modal parameters configuration principle based on spectrum indexes is proposed,which can realize the configuration of modal parameters with arbitrary given spectrum index.(4)A systematic resonant mode design criteria based on modal parameters configuration is established,which can make arbitrary coil MC-WPT systems to resonate at arbitrary given bands.By constructing all electric parameters that affect the modal parameters into a parameter space and deeply analyzing the intrinsic physical correlation between the parameter space and modal parameters,the mapping function relationship between the parameter space and the modal parameters is established.Then according to the mapping function,the actual modal parameters of MC-WPT systems are designed with the configured modal parameters as the target,which forms a set of resonant mode design principle to make MC-WPT systems resonate at arbitrary given bands.In this paper,the system mechanism modeling,resonance mechanism analysis,modal parameters configuration and resonant mode design are carried out in order,and a theoretical and technical system with modal parameters as the trajectory for resonant mode analysis and design of MC-WPT systems is established,which will produce a good impetus for the improvement of the basic theory of MC-WPT technology.The research results of this paper will effectively improve the energy efficiency and space capability of MC-WPT systems and then promote the practical process of MC-WPT technology.