Transcutaneous Energy Transfer System for Powering Implantable Biomedical Devices

Time varying magnetic fields can be used to transfer power across the skin to drive implantable biomedical devices without the use of percutaneous wires. However the coupling between the external and internal coils will vary according to orientation and posture. Other potential sources of power delivery variations arise from changes in circuit parameters and loading conditions. To maintain correct device function, the power delivered must be regulated to deal with these variations. This paper presents a TET system with a closed loop frequency based power regulation method to deliver the right amount of power to the load under variable coupling conditions. The system is capable of regulating power for axially aligned separations of up to 10mm and lateral displacements of up to 20mm when delivering 10W of power. The TET system was implanted in a sheep and the temperature of implanted components is less than 38.4 degrees over a 24 hour period.