Wireless Power Transmission Technology Based On Electromagnetic Coupling

The magnetic-coupling wireless power transmission system is able to transit energy to certain distance wirelessly by using mutual inductance coil. This technology transits electrical power through magnetic coupling and thus eliminates the necessity of transmission line. Therefore, it has become a significant topic that is hotly pursued by the scientific community all over the world. The technology spans many areas as it combines power electronics technology, electrical theory, microwave engineering and information technology.The thesis only concerns wireless power transmission within short distance. The major research interests of the paper is to investigate the efficiency and impact factors on the coupling coefficient of mutual inductance. The study is conducted by mathematical derivation, simulation and experiment. The main content of the paper is as follows:Study the basic principle of three kinds of wireless power transmission and compare the advantages and disadvantages. For the merits of the proximity high power energy transmission, the author choses magnetic coupling wireless power transmission as the research topic. Based on mutual model, establish the circuit model of magnetic coupling wireless power transmission system. Obtain the expression of the compensation capacitor, the output power and the efficiency.Propose a program to calculate the inductance and coupling coefficient of mutual inductance coil based on the method of numerical integration. Investigate the output power and efficiency of the system. Analyze the problems of compensation capacitor at different frequencies. Taking into account the features of coreless mutual coil system and the need of proximity high power energy transmission, the paper suggests two main methods to improve the system:improve the operating frequency and use loosely coupled transformer. Select the loosely coupled transformer according to the advantages and disadvantages of those two methods.Wrote command stream, use ANSYS to calculate the inductance and coupling coefficient of loosely coupled transformer. Analyze the inductance and coupling coefficient with different shapes of cores and different lengths of air gap. Investigate the influence of the relative permeability and displacement of the core. Figure out the relationship between the inductance and coupling coefficient and the output power and efficiency.Design a loosely coupled transformer to build experiment platform. Lighted up a 160W incandescent on a distance of 1mm. The efficiency of the system is more than 80% when the air gap is shorter. Improve the system based on the results of simulation and experiments.