| The single wire power transfer(SWPT)technology was first proposed by Tesla more than 100 years ago.However,due to the principle,technology and other reasons,this technology has been rarely studied.Higher transmission efficiency,longer transmission distance and higher security synchronously can be realized by SWPT,compared with wireless power transfer(WPT).It can realize true wireless power transfer when the guide wire is replaced by other materials,such as human body,seawater,soil,etc.As a result,SWPT technology has a wide range of application prospects in implantable medical equipment,wireless sensor network,power supply for islands at sea and remote mountain areas,etc.The transmission characteristics of SWPT system have not been studied so far.In order to promote the general application of this technology in practice,and better to replace the guide wire with non-metallic medium,and solve the problem of power,efficiency and distance in the transmission process.In this paper,the characteristics of SWPT are studied by simulation and experiment.Firstly,according to the structure of SWPT system and electromagnetic theory,the propagation process of electromagnetic wave in the guide wire is analyzed.The wave equation of electromagnetic wave propagation on the guide wire is obtained,and the instantaneous expressions of electric field strength and magnetic field strength are obtained according to the attenuation constant.Secondly,the finite element simulation model of SWPT is established and the modeling steps are briefly described.And then this paper simulates the characteristics of power,efficiency and distance in order to obtain the relationship of each characteristic and the distribution of space electromagnetic field.The simulation of the newly discovered dead zone characteristics verifies the existence of the dead zone and proposes a solution to the dead zone.The influence of the guide wire parameters on the transmission efficiency is obtained by changing the shape and thickness of the guide wire.Finally,experiment system is established.According to the characteristics and matching range of the matching structure,the structure of the impedance matching network is determined,and a variety of fixed-point impedance matching networks are designed.In order to increase the applicability of SWPT technology in various occasions,a variety of harmonic coil structures are designed.The power characteristics,efficiency characteristics,distance characteristics and dead zone characteristics are studied and the simulation results are verified.It is proved that the non-metallic conductor can replace the metal conductor to transmit electric energy. |
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