Comparative evaluation of IPT resonant circuit topologies for wireless power supplies of implantable mechanical circulatory support systems

Abstract

Abstract-Today's implantable blood pumps, such as Left Ventricular Assist Devices (LVAD) are powered by means of a percutaneous driveline, which constitutes a severe risk of infection to the patient. Inductive Power Transfer (IPT) technology offers a solution to replace the driveline by a wireless energy link. In this paper, three commonly used IPT resonant circuit topologies are compared regarding power transfer efficiency and heating of the tissue. In the course of the analysis, the main advantages and disadvantages of each topology are identified and as a result it was found that regarding the heating of the tissue, the series-series compensated topology is the most promising solution for Transcutaneous Energy Transfer (TET) systems capable to provide a peak power transmission of up to 30 W. Operated at the resonant frequency using an efficiency optimal control, the series-series compensation topology achieves the highest DC-to-DC power conversion efficiency in the coil coupling and output power range, but requires a higher complexity of the control system, and more important, it shows an increasing secondary side coil power loss with decreasing coil coupling factor. In contrast, the operation near the frequency for load independent voltage gain using a load impedance control technique achieves similar power conversion efficiencies at high coil coupling factors, but offers a lower complexity of the overall TET system. The peak DCto-DC efficiency measured with a hardware prototype is 97 % at a coil separation distance of 10 mm, a primary and secondary coil diameter of 70 mm and ideal coil alignment. Even at a coil separation distance of 20 mm and an output power of 5 W, the efficiency is 90.5 %.

Modelling and analysis of the distortion of strongly‐coupled wireless power transfer systems with SS and LCC–LCC compensations

“…The application of wireless power transfer (WPT) ranges from lowpower scenarios like consumer electronics [1] and implantable medical devices [2] to high-power scenarios like electric vehicles [3] and railway transit [4], achieving convenience, safety, maintenance freedom, and longevity of devices due to reduced sparks. Magnetic induction WPT, or inductive power transfer (IPT), has received the most extensive research and commercial penetration [5][6][7][8].…”

Power Loss Shifted Design of Inductive Energy Transfer Systems

“…This leads to effective quality factors Q C Q L . Therefore, for this particular application, the power losses of the compensation capacitors can be neglected [14]. Still, it needs to be mentioned that capacitor losses can become relevant due to different applications and capacitor technologies [3].…”

“…There exists a variety of publications regarding the optimization of thermal losses and efficiency. These include the optimization of power electronic components [5], [25], the magnetic domain [3], [13] and the employment of reactive power compensation networks on primary and secondary side of a transfer system [14], [19]. Various publications present the design of inductive energy transfer systems with respect to the maximization of the overall efficiency for a specific load condition [2], [11], [12], [16], [21], [24].…”

Simultaneous Wireless Information and GaN-Based Power Transfer Exploiting a Dual Frequency Band

“…The voltage gain depends on the distance of the coils, hence the coupling factor, the effective load resistance, and the operating frequency. Having primary converter control with near resonant frequency operation for regulation can lead to lower efficiency despite reduced number of processing stages [10]. To add another degree of freedom, voltage can be controlled via a primary and/or secondary DC/DC converter or specialized modulation schemes of the main DC/AC converter, i.e.…”