Transcutaneous Energy Transmission System For Artificial Heart

With the rapid development of life science and bio-engineering, the research of implanted medical device, especially the totally artificial heart (TAH), has made great progress, and the TAH with the character of miniaturization, durability and low-resistance, might be used as widely as the artificial pacemaker. The original electric artificial heart is connected with the battery by the wires which penetrate the skin, leading to high ratio of cross-infection. With the use of transcutaneous energy transmission system (TETS) which does not have any physical connection with the outer battery to drive the TAH, it has greatly prevented infection complications and improved the life quality of the patients. With the development and improvement of this technology, non-invasion and low-risk treatment in medical field will be further promoted, thus it has great research value and application prospect.In this paper the TETS, which consists of the transcutaneous energy transmission and temperature data communication through intact skin to power a TAH, has been designed and built. Main tasks are as follows:1. The factors affecting the contactless transformer of TETS coupling efficiency(k) are analyzed. With the help of the finite element analysis software, the coupling performance and stability of the transformer are analyzed. And then core material, air gap, geometrical parameters, and coils axial displacement are selected to study their effects on coupling coefficient. By simulating with various values, the transformer is designed. Then a type of high coupling and small size coil is proposed in this paper, which solve the design contradiction between transcutaneous transformer and transmission efficiency.2. The working frequency 100 kHz of the TETS is determined according to the primary and secondary current ratio of the transcutaneous transformer. Compared of various compensation methods, it can be obtained theoretically that two capacitors added in series on both sides to compensate the leakage inductances is more suitable for the TETS.3. The coupling and energy transmission characteristics mainly including three aspects of the TETS are studied experimentally. Firstly, the coupling for the pot and PM (Pot Module Cores) core transformer with frequency, load, air gap and horizontal displacement is investigated. Secondly, the power transmission characteristic of the TETS with frequency, load, air gap and horizontal displacement is studied with the experimental pot core transformer. Lastly, the applicability of various compensation methods is studied experimentally. The most efficient compensation method of the TETS for TAH, of which two capacitors are added in series on both sides, is obtained experimentally.4. The temperature field of transcutaneous transformer is established. Furthermore, an information transmission system is proposed. Through monitoring the temperature of secondary core which reflects the value of load power, the change of temperature can adjust the input power of the primary coil to achieve high system reliability. And a transcutaneous data communication system based on JASK2000 development board is built.5. The hardware platform of charging and discharging experiments is built. On the basis of that, the expected life-span of the TETS using the energy conservation theory is deduced, and accordingly its validity is approved. Actural 3-period charging and discharging experiments is operated.