An Externally-coupled Transcutaneous Energy Transmission System for Totally Implantable Artificial Hearts—Detection of Abnormal Coupling Caused by Misalignment and Air Gap in the Ferrite Core Junction of the Transcutaneous Transformer

Abstract

It is typical to supply energy using a transcutaneous transformer for driving implantable artificial hearts. Producing an abnormal coupling in the transcutaneous transformer causes the temperature of the transformer to rise higher, even if energy transmission is possible. In this paper, two typical cases of abnormal coupling are investigated : slide misalignment and the air gap produced in the junction of the ferrite core. The former abnormal coupling was detected by coils set on the junction linked with the magnetic flux in the ferrite core, and the latter abnormal coupling was detected by a hall device set on the side of the junction. As a result, it was found that a slide misalignment of more than 1 mm and an air gap of more than 0.1 mm in the junction were detectable, respectively, and that it is possible to provide an alarm when detected. It is concluded that the detection and warning of abnormal coupling in the transcutaneous transformer, as investigated in this paper, are possible.