The Technology And Application Of Wireless Power Transmission Through High Loss Medium

In recent years, wireless power transmission technology is widely used in Consumer electronics, automation equipment, medical electronics and military equipment.It make people's life more convenient because energy is no longer bound to pass within the wire. While wireless power transmission has a good performance through the air medium and insulator. Majority of technical methods can not be applied directly in the occasion through the high loss medium,such as metal, mud, salty liquid. The transmission efficiency is severely degraded, or even completely blocked if we directly use these methods. In order to solve this problem, this paper studies the wireless energy transmission through high loss medium,which mainly includes the following four aspects of the work:First of all, we analyze three common forms of wireless power transmission technology. The principle model and application of the inductive coupling and magnetic resonance are discussed detailed. We analyze the loss characteristics of the high loss medium and the shielding performance of high loss medium for Electrical, magnetic and electromagnetic wave. We obtain the conclusion that the low frequency magnetic field has the worst shielding performance through the high loss medium. This can also be explained that low frequency magnetic field can be used as the carrier of energy.Second, the wireless transmission experiments are carried out through high loss medium. We select three typical high-loss medium as research subjects which are brine absorbing materials and metal. We designed the experimental system and conducted transmission experiments of different frequency which is from 1MHz to 30 MHz with contrast, magnetic fields and electromagnetic waves. The results showed that low frequency magnetic fields has minimum attenuation through the high-loss medium.Third, the electromagnetic coupling transmission model is established. An equivalent circuit model of mutual inductance coupling is established.In the model,we consider two types of loss mechanisms which are conduction losses and eddy current losses. The validity of the model was verified, and get a typical reference data by finite element and experimental methods.Finally, we designed a wireless energy transmission system through the metal. Since the decrease of frequency results in the decrease of coil impedance, we propose an impedance conversion technology to match impedance. Simultaneously we used the parallel resonance technology to provide a low voltage and high current drive source. The test result shows that,on one hand, the metal medium layer results in the decrease of the coil inductance and the increase of equivalent resistance which is consistent with our model for trend;on te other hand, the efficiency can reach 27.2% when through 0.1mm thick copper. when through 0.3mm thick copper, the efficiency can reach 2.89%. The efficiency is increased compared with the same literature.The main results of this paper, on the one hand, theoretically clarify the reason that the low-frequency magnetic fields can penetrate the high loss medium; on the other hand, propose a wireless energy transfer technology that can penetrate metal. The results of this paper can also be applied to underwater wireless power supply, mud wireless power supply, and wireless power supply of human organs.