| Magnetically coupled resonant wireless energy transmission technology has the advantages of medium transmission distance,small influence by magnetic obstacles,large output power and high efficiency.It is mainly used in electric vehicles,biomedical and other fields.At present,this technology has become a research institute at home and abroad.The research focus of universities and colleges,but there are still some problems in the design of coil structure parameters.The existing coil design methods are generally implemented by centralized parameter theory or by means of finite element simulation software.The design method has certain limitations and is difficult to construct quantitative relationship between output power,transmission efficiency and coil parameters,and scientifically guide coil design.In this paper,for the two-coil cylindrical spiral coil structure,from the electromagnetic field point of view,the coil space magnetic field is used as the medium,and the quantitative relationship between the system's power characteristics and the coil parameters is established by the piecewise accumulation method,and the feasibility verification is carried out from both theoretical and experimental aspects.The main research work of this paper is as follows:(1)By comparing the coupled mode theory of the magnetically coupled resonant radio energy transmission system with the applicable occasion of the mutual inductance theory,it is pointed out that it is difficult for both theories to establish the relationship between power,efficiency and coil parameters in essence,and to guide the coil design.Based on the principle of magnetic resonance system and the working conditions,the energy transmission characteristics of the system are analyzed by using near-field and quasi-static magnetic field.The magnetic field analysis model of the resonant coil is established under the condition of magnetic quasi-static field.The mathematical relationship between the transmitting coil and the receiving coil voltage,current,and the coil space magnetic field,coil radius,number of turns,and wire diameter are established.(2)Based on the magnetic field analysis model of the magnetic coupling resonant coil,the space magnetic field of the coil is calculated by the segmented accumulation method,and the spiral coil design is realized.The radius,the number of turns and the coil wire diameter are studied by the segmented accumulation method under the constraint condition.The relationship between power and efficiency is compared with the simulation results of mutual inductance theory.The variation of coil radius,number of turns,wire diameter,power and efficiency obtained by segmented accumulation method is the same as the mutual inductance theory,and the determined coil parameters are the same.From the theoretical point of view,the feasibility of designing spiral coils by segmented accumulation method is demonstrated.(3)Design a magnetic coupling resonant radio energy transmission experimental system,including designing high frequency inverter circuit,drive circuit,transmitting coil and receiving coil structure and load selection.(4)The experimental platform of magnetic coupling resonance system is built,and the driving board debugging experiment,inverter experiment and resonance point matching experiment are carried out to ensure that the system can realize wireless energy transmission normally.For the experimental feasibility of the segmentation accumulation method,the coil radius and turns are performed.The number and wire diameter experiments have determined that when the constraint conditions are met,when the coil radius,the number of turns and the wire diameter are around 157 mm,16 turns,and 3.56 mm,respectively,the transmission power meets the conditions of output power with higher transmission efficiency 79.7%,the simulation and experiment determined that the coil parameters are basically the same,and the experimental feasibility of designing the coil parameters by the piecewise accumulation method is demonstrated. |
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