Development of transcutaneous energy transmission system

The transcutaneous energy transmission system has been developed for use with electric artificial hearts. The system is composed of a transcutaneous transformer, power oscillator, and output power conditioning system. The transcutaneous transformer is formed from two ferrite cores. The external core is concave at the base and the internal core convex at the top. Since the internal core causes a bulge in the skin, the projections on the external portions can engage the internal portion of the primary core and prevent lateral motion of the primary core. The number of turns of the coils is determined in order to satisfy minimum power loss conditions. The power oscillator converts the power drawn from an external 12-V dc source into a 50-kHz square wave to excite the primary coil. Both the primary and secondary coils are series-tuned at the operating frequency using capacitors. Output voltage is regulated by controlling the duty ratio of the square pulse supplied to the primary coil. Information on output voltage is transmitted through the skin by infrared pulses.