| Compared with magnetic induction technology and microwave energy transmission,magnetic resonance coupled wireless energy transmission technology has the advantages of moderate distance,moderate efficiency,and moderate power.Therefore,it has been a research hotspot for domestic and foreign scholars in recent years.At present,there are some problems in this technology,such as the transmitting coil and receiving coil need to be placed directly opposite,efficiency is affected by changes in transmission distance and changes in the relative position of the transmitting coil and receiving coil,and the efficiency of the system is low.In this paper,the efficiency of magnetic resonance coupled wireless transmission system with frequency of 13.56 MHz is studied.A high-efficiency power amplifiers,high-efficiency transceiving coil,and rectifier voltage regulator circuit are designed.The article seeks to improve the efficiency of various modules to achieve the efficiency of the system.In addition,some of the major problems mentioned above are solved by the improved design of the coil structure and the matching optimization circuit.The main research contents and innovations of this paper are as follows:1)In order to improve the efficiency of the source,a high-efficiency power amplifier with a working frequency of 13.56 MHz has been designed.The operating frequency of power amplifier is 13.56 MHz and the output power is greater than 10 W.Through circuit simulation optimization and experimental debugging,the efficiency of power amplifier is greater than 80%.2)A planar spiral transceiving coil with operating frequency of 6.78 MHz and 13.56 MHz are designed.Through modeling and simulation,circuit matching and efficiency optimization,the maximum efficiency corresponding to any transmission distance is achieved.The effect of the changes of the transmission distance on the efficiency is analyzed,and the method of capacitance matching adjustment is proposed to realize that the energy transmission efficiency is adjustable with the change of distance,which is verified by experiments.3)In this paper,the structure of the array coil is used to effectively realize the uniform distribution of the spatial magnetic field.When the receiving coil is moved and charged in any direction within a certain range above the transmitting coil,the transmission efficiency can be maintained basically unchanged,and the problem of point-to-point transmission is solved.At the same time,through the method of capacitance matching optimization,the transmission efficiency of the transceiving coil is stable when the receiver coil is placed arbitrarily within a certain tilt angle.The problem of declining efficiency in the case of non-adjustment is solved.This method is verified by model simulations and experimental tests.Based on this,optimization simulation and testing of transmission efficiency at the time of multiple receivers are performed.4)The rectifier voltage regulator module is designed and fabricated,and a magnetic resonance coupled wireless energy transmission system is built to test the system efficiency.At the same time,experimental tests are conducted on the working status and stability of the system under one-to-many wireless charging occasions such as mobile phones and LED lights as well as complex application scenarios. |
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