Research on transmission characteristics of magnetically coupled resonant wireless power transfer system

In view of the influence of coil parameters and load resistance changes on transmission performance of magnetically coupled resonant wireless power transfer(MCR-WPT) system, output power and efficiency of the system are derived using equivalent circuit model of two coil structure MCR-WPT system. The relationship between coil mutual inductance, load resistance and system output power and transmission efficiency, as well as the relationship between coil wire diameter, coil turns and mutual inductance are analyzed. Three-dimensional coil model is established using finite element simulation software COMSOL, and multiple sets of two-coil MCR-WPT experimental systems are built to verify the theoretical analysis results. Research results show that by increasing coil wire diameter and turns, the output power and transmission efficiency of the system can be improved, but the influence of turns on transmission efficiency is more obvious than that of coil wire diameter, and the transmission distance increases when the maximum output power is obtained as the turns increases; as the load resistance continues to increase, the system output power and transmission efficiency both increase first and then decrease, proving that output power and transmission efficiency both have maximum value, but the optimal load is different when the system output power and transmission efficiency reach the maximum value, that is, there is no optimal load resistance that can maximize the output power and transmission efficiency at the same time.