Analysis And Design Of 2-Dimensional Omnidirectional Wireless Power Transfer System With Low-Power

Wireless power transfer is a new way of power supply,which can avoid troubles caused by messy cables in traditional plug-in charging systems.The traditional wireless power transfer technology only solves the problem of one-dimensional and single-direction power transmission.With the expansion of social practical application requirements,omnidirectional wireless power transfer technology has gradually received extensive attention and research to realize the power transmission of electrical equipment at different locations within a certain spatial range.Omnidirectional wireless power transfer is a technology that can meet the omnidirectional demand for the non-contact power supply.Generally,planar coils cannot achieve omnidirectional distribution of the magnetic field.Therefore,omnidirectional wireless power transfer technology requires the design of omnidirectional magnetic coupler,combined with reasonable compensation network and magnetic field control mode to achieve multi-directional magnetic field distribution.The omnidirectional wireless power transfer system designed in this paper includes a two-dimensional orthogonal transmitting coil and a single cylindrical coil receiver.Meanwhile,the compensation network,magnetic field control and phase shift control strategy are analyzed and designed for the coupler;also,the simulation and experimental verification are carried out.Firstly,a two-dimensional orthogonal magnetic coupler is designed in this paper.In order to realize the independent control of the input current of the orthogonal transmitting coil,from the basic magnetically coupled resonant wireless power transfer,an LCC/S resonant compensation network is finally used to realize the constant voltage output of the receiving coil at a certain offset by comparing several common compensation networks.According to the mutual inductance circuit model and the fundamental harmonic approximation,the system circuit with LCC/S resonant compensation network is mathematically modeled.The transmission characteristics and efficiency of the system without control method are obtained.Secondly,based on the analysis of the circuit part of the system,two magnetic field control modes of magnetic field vector rotation and magnetic field vector orientation for two-dimensional orthogonal transmitting coils are proposed to realize the active control of spatial magnetic field distribution.According to the vector synthesis theory,the principle of magnetic field vector synthesis rotation and magnetic field vector orientation is analyzed in detail.The expression of controlling the distribution of synthetic magnetic field by controlling the excitation current is given and the control strategy of phase-shifted full-bridge is designed.By modeling the magnetic field distribution of the single-turn orthogonal coil,the magnetic field intensity at any point in the omnidirectional and the spatial mutual inductance distribution of the magnetic coupler are obtained.Based on the above analysis,the transmission characteristics of the system under magnetic vector rotation control and magnetic vector orientation control are obtained respectively,and the relationship between the transmission efficiency and the position of the receiving coil is compared mathematically.Finally,to verify the theoretical analysis,the magnetic field characteristics of the two control methods are analyzed by Maxwell simulation,and the feasibility of the magnetic field vector rotation and magnetic field vector orientation control methods is verified by Simulink simulation.Meanwhile,an experimental prototype is designed and built in this paper.The working waveforms of the prototype in two modes are measured,and the spatial distribution of transmission efficiency is statistically obtained.The simulation and experimental results show that two control modes can be effectively applied to an orthogonal magnetic coupler for omnidirectional wireless power transmission,and the efficiency of the magnetic vector orientation mode is better than that of the magnetic vector rotation mode,with an average efficiency increase of 33.18%.