Abstract
To supply power for driving a totally implantable artificial heart, one of the most advantageous methods is to transmit it through the skin in the form of electromagnetic energy from outside the body. In principle, such transcutaneous energy trans-mission is possible by means of electromagnetic induction between two coils placed face to face on each side of the skin. With such a construction, however, the coils are liable to dislocate themselves by the movement of the body, resulting in the reduction of the energy transmission and efficiency. In the externally coupled coil system proposed in this paper, part of the internal coil is protruded out from the body in the form of an arch, but with the skin completely covering it. Into the hole of the arch is inserted a ferrite core, and on the core is closely wound the external coil. This coil configuration not only assures stability of operation, but also a greater coupling between the coils. Results of in vitro measurement showed that the average transmission efficiency (DC to DC)is 79% with the load changing from 5Ωto 50Ω. Also, reduction of efficiency due to dislocation of coils was found to be less than 1%, showing that this new system can be used without the necessity of coil alignment.
