Externally-coupled transcutaneous energy transmission for a ventricular assist device-Miniaturization of ferrite core and evaluation of biological effects around the transformer

This paper reports on the miniaturization of the ferrite core of an externally-coupled transcutaneous transformer (ECTT) for a ventricular assist system. First, we designed the miniaturization of the ECTT and measured the transmission efficiency. We investigated whether the ferrite core of the ECTT could be miniaturized without a decline in the efficiency. Secondly, the electromagnetic simulator was analyzed via the specific absorption rate and the internal electric field strength in the human body by employing the transmission line modeling method. As a result, a maximum energy transmission efficiency of 98.20% (12 turns) was obtained by the miniaturization of the ECTT. Additionally, electromagnetic analysis of the biological effects revealed that the internal electric field falls well below the guidelines of the International Commission on Non-Ionizing Radiation Protection for frequencies above 300 kHz. The miniaturized ECTT is confirmed to be safe for transmission frequencies over 300 kHz.