Power loss shifted design of inductive energy transfer systems

Abstract

This article proposes a design procedure for power loss shifted inductive energy transfer systems. Based on adequately simplified mathematical circuit models for four different compensation topologies, the load dependent losses of the respective resonant circuits are presented. Power loss shifting is achieved for transfer coils and their compensation capacitors by adjusting the design operating area of the transfer system. As a result, this leads to asymmetrical reactive power and loss distribution on primary and secondary side. Design equations for coil systems and compensation capacitors with predictable transfer and loss behavior are provided. Strategies and equations for the determination of the operating area are given. The procedure can be adapted to many kinds of applications where power losses on either primary or secondary side of an inductive energy transfer system are key to be avoided and further miniaturization needs to be achieved. This strategy offers an additional degree of freedom that can be taken into advantage regarding the reduction of thermal heating or miniaturization efforts. A comparative metrological validation for the application of transcutaneous energy transfer shows that the losses of the secondary implanted components can be drastically reduced with the drawback of a decreased efficiency of the overall system.