A Three-Coil Coupled High-Efficiency Power Link for Wireless Power Transfer Application

Recently wireless power transmission (WPT) has gained a tremendous level of interests in scientific, domestic, and civil applications. Out of several WPT schemes, the nearfield magnetic link shows potentials for short distance wireless power and data transmission. However, the power-transmission efficiency of magnetic link is limited by the low coupling factor and the quality factors of the transmitter and the receiver coils. To overcome this challenge, a high-efficiency three-coil inductive power link with resonant capacitor is proposed to improve the working bandwidth. Prototype coils are designed and fabricated on FR4 substrate and HP 4396B Network Analyzer is used to measure the performance of the 3-coil link system. Simulation and measurement results indicate that the proposed system has a transfer gain 42 dB higher than that of the two-coil coupled inductive link under resonant condition.