Investigations on the "Direct Digital Inductance Estimation" - Concept for Self-Sensing AMBs Under Influence of Eddy Currents

This article states the challenges connected with eddy-currents by use of the direct digital inductance estimation (DDIE) concept for self-sensing active magnetic bearings. Starting with a short introduction to the estimation algorithm, the negative influences of eddy currents on the position estimation are described step by step. Such influences are an increasing position noise as well as an interval and duty cycle dependent position error. The article closes with an outlook on additional investigations to further separate, quantify, and reduce the associated position error in order to extend the performance of the DDIE-concept.