Methods for Compensation of Coil Misalignment in Systems for Inductive Transcutaneous Power Transfer to Implanted Medical Devices

Abstract

The problem of variation of the output characteristics (voltage, current, power) of inductive powering systems for implantable medical devices is considered. The variation is primarily caused by relative misalignment of transmitting and receiving coils. A classification of misalignments is proposed. Main approaches to coil misalignment compensation are: mechanical fixation of the coils; evaluation of the relative position of the coils for elimination of misalignment or further tuning of the transmitting part of the system; optimization of the coil geometry providing stability within the given misalignment range; tuning the working frequency of the transmitting part of the system. It is shown that the compensation method should be selected with due regard to the implantable device parameters (first of all, the coil implantation site and the power consumption of the device).