Research on Anti-offset Performance of the Wireless Power Transfer System with Asymmetric Coupling System

Abstract

Coupling system is important for a Wireless Power Transfer (WPT) system, and it directly affects the efficiency and reliability of the WPT system. In some special applications, such as implantable medical devices, the size of the receiving coil of the WPT system is strictly limited. Coupling coils of equal size will not meet the application requirements. When being applied in implantable medical devices, equal-size coupling coils suffer from shortcomings such as poor anti-offset performance and cumbersome design process. In view of the above problems, in this paper we design a coupled coil structure asymmetrically, so that parameters such as outer diameter and the number of turns of the transmitting and receiving coils are no longer equal. In this paper, we first analyze the effect of tightly wound and loosely wound coils on the WPT system when they are used separately as transmitting coils and find that the two different types of coils have different characteristics of the magnetic induction intensity distribution. Then, we use the genetic algorithm to optimize the transmission coil and design a new asymmetric coupling system. Finally, we experimentally demonstrate that the optimized coupling system is able to maintain the stability of the output current and the transmission efficiency within a certain range in the presence of offset, which indicates that the coupling system has a certain ability of anti-offset.