Online Optimization of Inductive Power Transfer using RF Feedback

Inductive powering is proven to be an effective method to power implantable as well as wearable data acquisition systems. However, the amount of transferred power is highly dependent to patient and sensor movement. This paper introduces an online control system for wearable applications, using an RF feedback loop to regulate the transferred power level in case of loose coupling. A wireless magnetic link, operating at 1 MHz, has been developed. It comprises a dedicated class E power driver, tuned for an inter-coil distance of 100 mm, at the primary side, and a sensor module (⌀ 15 mm x 4 mm), used to measure human activity, at the secondary side. A high data rate RF transceiver, operating in the 2.4 GHz ISM band, is used for both sensor data transfer and wireless power feedback. The system is able to support a constant energy level at the secondary side for dynamic coil distance variations between 35 and 200 mm. This approach significantly improves power efficiency of an inductive link with respect to earlier work. In addition, the RF link provides a real-time indication of the generated inductive field to which the subject is exposed, increasing patient safety awareness.

Jaar van publicatie:2012

Toegankelijkheid:Closed