Comprehensive Modeling of Magnetoinductive Wave Devices for Wireless Power Transfer

Abstract

This work presents an analytic model based on the impedance matrix that can predict the transferred energy to a movable receiver device in the near field of a magnetoinductive wave transmitter array. The formulas we present apply to any resonator geometry that can be described as a set of horizontal and vertical segments. The model accurately describes the system efficiency with respect to the operating frequency and to less constraining spatial configurations of the receiver device. The formulated expressions can be easily applied to distinct wireless power transfer system configurations, such as a single pair or an array of resonators, regardless their configuration. We demonstrate that the spatial resolution of the efficiency calculation is limited when only the first coupling order between the receiver and the transmitter array is considered. However, high resolution is possible when first and second coupling orders are included. Additionally, we show that the model foresees the terminating impedance modulation schemes that we applied only after evaluation of data obtained experimentally. These modulation schemes prevent the receiver from standing above a power null resulting from the interaction of forward and backward traveling waves, one of the major challenges in traveling wave based wireless power transfer devices.