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A transcutaneous energy transfer (TET) system has been developed to power implantable devices such as artificial hearts, defibrillators, and electrical stimulators. Transcutaneous coupling of power to these implanted de‐vices remains a favorable alternative as percutaneous lines are avoided in order to eliminate the potential of infection and allow patient mobility. In vitro, in vivo, ex vivo, and human cadaver studies of the electrohydraulic ventricular assist device TET have demonstrated that power can be transmitted over a range of skin thicknesses of 3–15 mm and can tolerate radial misalignments of up to 20 mm. Sensitivity to coil separation and radial misalignment variations has been addressed by the development of an auto‐tuning TET. The system has only a 10% attenuation in secondary coil voltage when metallic objects are in contact with the primary coil. The system has demonstrated a power transfer efficiency of 60–80% for power demands from 5 to 70 W. The TET secondary coil will provide an output voltage of 10–25 V for current demands from 0.5 to 4.0 A. TET chronic studies in porcine models have demonstrated no adverse effect to the tissue when up to 40 W of power can be delivered to an implanted load without the tissue‐contacting surface of the coil exceeding 42°C. In conclusion, the TET is a feasible alternative for tether‐free power transmission.

Rotary blood pumps often require a constant operating voltage. To meet this requirement and to eliminate the need for percutaneous leads, a voltage-regulated transcutaneous energy transfer (TET) system has been developed. Voltage regulation is achieved by using a transcutaneous infrared feedback control loop operating on a 890 nanometer (nm) wavelength. In vitro testing of the system developed has shown that output voltage can be maintained to within 0.2 V of nominal (14.5 V) for delivered powers up to 50 watts (W) and coil separations of between 3 and 10 mm. Power transfer efficiencies were determined to be from 68% to 72% over the tested range of coil separations and output currents from 1.5 to 3.6 amperes (A). This system has demonstrated acceptable performance in regulating output voltage while transferring power inductively without using percutaneous connections. By integrating this type of TET system with an implanted rotary blood pump, the quality of life for the device recipient could be improved.

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