Comprehensive Analysis and Measurement of Frequency-Tuned and Impedance-Tuned Wireless Non-Radiative Power Transfer Systems

摘要

This paper theoretically and experimentally investigates frequency-tuned andimpedance-tuned wireless non-radiative power transfer (WNPT) systems.Closed-form expressions for the efficiencies of both systems, as a function offrequency and system (circuit) parameters, are presented. In thefrequency-tuned system, the operating frequency is adjusted to compensate forchanges in mutual inductance that occur for variations of transmitter andreceiver loop positions. Frequency-tuning is employed for a range of distancesover which the loops are strongly coupled. In contrast, the impedance-tunedsystem employs varactor-based matching networks to compensate for changes inmutual inductance and achieve a simultaneous conjugate impedance match over arange of distances. The frequency-tuned system is simpler to implement, whilethe impedance-tuned system is more complex but can achieve higher efficiencies.Both of the experimental WNPT systems studied employ resonant shielded loops astransmitting and receiving devices.