Analysis and Design of Ideal Transformer-Like Magnetic Coupling Wireless Power Transfer Systems

An ideal transformer-like (IT-like) magnetic coupling wireless power transfer system is proposed in this article, which can achieve a large constant power and efficiency output over a wide transfer range. First, the general circuit model is presented along with the analysis of fundamental and harmonic current characteristics. Then, the IT-like operation mechanism with a fixed desired secondary-primary current amplitude ratio independent of mutual inductance is proposed, based on which the transfer range capable of both power and efficiency is greatly improved. The corresponding parameter criteria and implementation methods, including the zero-phase-angle mode and the zero-voltage-switching mode are derived and verified in a practical prototype. The experimental results show that the proposed system can take the output power, transfer efficiency, transfer range, and current characteristic into account at the same time, with strong position robustness and high tolerance to variable couplings.