Research On Full Space Wireless Power Transfer System And Magnetic Energy Control Method

Magnetic coupling wireless power transfer(MC-WPT)technology,as a new power transfer technology,uses the principle of magnetic field coupling to realize the transfer of power from the power supply side to the electric side.It gets rid of the constraints of the traditional wire with tail charging.It has the advantages of safety,reliability,flexibility and convenience.However,due to the disjoint magnetic field lines in the surrounding space of MC-WPT system,there exists "invalid energy transfer space".At present,most MC-WPT systems have low degree of freedom of power transfer in three-dimensional space,and the range of power transfer is relatively limited,which limits the promotion and application of this technology to a certain extent.Aiming at this problem,this thesis takes the three-dimensional orthogonal coil architecture as the node,constructs a multi-node distributed energy transfer architecture in a certain space range,including centralized and distributed working modes,which can effectively increase the space range of power transfer.On this basis,a dynamic magnetic energy control method of MC-WPT in three dimensional space is proposed.Combined with the proposed system architecture and method guidelines,by comprehensively regulating the combination structure of excitation source coils and the current amplitude ratio of transmitting coils,the magnetic field direction at any position can be controlled within the effective energy transfer range,eliminating the influence of "invalid energy transfer space",and realizing all-directional,all-angle,low magnetic leakage,accurate and efficient power transfer within a certain space range.The main research work of this thesis is as follows:Firstly,based on the principle of space vector synthesis,three magnetic field vectors in different directions are determined,and magnetic field vectors in any direction can be synthesized by controlling their amplitude ratio.Based on this principle,a multi-node radio power transfer architecture with three concentric orthogonal loops as nodes is proposed.According to the different combination modes of threedimensional orthogonal transmitting coils,it can be divided into two modes: centralized three-dimensional orthogonal power transfer mode and distributed three-dimensional orthogonal power transfer mode,so as to meet the application requirements of different power transfer ranges.Aiming at the centralized power transfer mode,the mathematical expression of the magnetic field synthesized by each point in space under the centralized power transfer mode is established based on Maxwell equations and time domain analysis.Then,through matrix calculation,the amplitude ratio of the excitation current in the concentrated power transfer mode in the direction of the expected magnetic field can be deduced backwards,and the excitation current corresponding to the size of the expected magnetic field at any spatial position can be quickly obtained.On this basis,the COMSOL simulation model was built,and the magnetic energy regulation criterion of the centralized power transfer mode was verified.It was proved that the magnetic energy regulation method derived in this thesis can improve the spatial power transfer freedom of the MC-WPT system,and the space effective power transfer range under a certain current threshold was given.This model is suitable for short range full space power transfer system with fast response.Aiming at the distributed power transfer mode,based on the magnetic energy regulation criterion of centralized power transfer mode,combined with coordinate rotation,translation and reverse transformation,the magnetic energy regulation criterion of distributed power transfer mode is constructed,and the optimal node combination selection criterion under nonlinear programming is given.Also,a simulation model is built to verify the distributed power transfer system and the magnetic energy regulation criteria,and the distributed effective power transfer range is compared with the centralized effective power transfer range,which proves the superiority of the distributed architecture in improving the spatial power transfer range of the system.This model is suitable for long distance full space power transfer system with low power consumption node combination.Finally,an experimental verification platform was built to verify the centralized power transfer mode and the distributed power transfer mode respectively.It was confirmed that the power transfer architecture and magnetic energy regulation method proposed in this thesis can realize the control of the direction and size of the magnetic field at any position within the effective range of power transfer.Experimental results show that the proposed method can achieve all-directional,all-angle,no magnetic leakage,accurate and efficient power transfer within a certain space range.The centralized and distributed power transfer modes jointly improve the spatial power transfer freedom and spatial power transfer range of MC-WPT system.81 figures,14 tables,and 82 references are included in this thesis.