Theoretical study on wireless power transfer system via magnetic resonant coupling

• Main Author: Zhang, Xu
• Other Authors: Zhu Lei
• Format: Final Year Project
• Language: English
• Published: 2012
• Subjects: DRNTU::Engineering::Electrical and electronic engineering::Electric power::Production, transmission and distribution
• Online Access: http://hdl.handle.net/10356/50979
• Institution: Nanyang Technological University

Wireless power transfer via magnetic resonant coupling is a cutting-age technology which enables effective mid-range power transmission while the traditional inductive coupling WPT system failed to do so. Previous research papers successfully demonstrated the high efficiency of magnetic resonant coupling wireless power transfer technology, however the prior works that were more focused on static transmission distance condition were unable to fulfil more practical design requirements such as a moving user with laptop. This report takes the analysis of resonant magnetic coupling a step further, while explaining the key elements (frequency splitting, critical coupling, high circuit Q) to achieve high transfer efficiency. Firstly, the report states the theoretical basics of wireless power transmission with magnetic resonance. The basic wireless power transmission system and its equivalent circuit model are then introduced. Following this, voltage gain and system transfer efficiency is derived as a series of formulas. Those works are mainly developed by using traditional circuit analysis of electrical engineering. Investigation of these simplified formulas derives the essential principle (rate and range) for efficient wireless power transmission. Furthermore, this report will continue on an advanced wireless power transfer system and presents its high system efficiency with the help of simulation results and graphical data. At the end, improvements were suggested based on the study results from the circuit model, such as a solution against the frequency splitting phenomenon and how to avoid over-coupled situation. Generally, this report intends to lay down the ground work for middle range wireless power transfer technology and from there to show the possibility to commercially implement advanced electromagnetic resonance based WPT system.