Development of a transcutaneous energy transmission system - Use of air- core-type coils

To supply the electric power for driving a total artificial heart (TAH), a transcutaneous energy transmission (TET) system is advantageous. For a TET system with air- core-type coils, it is generally said that the electric energy can be effectively transmitted in the case that resonant frequencies of the serial LCR (coil-capacitor-resistor) circuits of both sides are the same as a driving frequency, but it is dangerous that a short circuit occur when a primary coil is away from a secondary coil and/or a secondary LCR circuit is open because of unloaded. In this study, a secondary resonant frequency is chosen to be higher than a primary one and a driving frequency is chosen to be higher than a secondary one, then it is able to keep away from a short circuit and keep energy transmission and its efficiency stable. The electric power of 40W can be transmitted to a dummy load with a resistance of 20Ω at sufficiently high efficiency.