Power Pulsation Suppression Methods for Noncoaxial Arc‐Surface Rotary Wireless Power Transfer System

ABSTRACT In noncoaxial rotary wireless power transfer (WPT) applications, the changing distance and angle between coils cause mutual inductance fluctuations, which in turn lead to significant output power pulsation, making it challenging to achieve stable power delivery. To realize stable power supply for rotary WPT systems, this paper investigates a typical noncoaxial arc‐surface rotary coil structure and provides a detailed analysis of the mutual inductance variation during coil rotation. Building upon this foundation, a multi‐Tx single‐Rx curved rectangular coil configuration is proposed to reduce the mutual inductance fluctuation between Tx and Rx coils, and the parameters design for the proposed coils is carried out based on the theoretical analysis of mutual inductance. To suppress the power pulsation at the output, a Buck converter is cascaded following the rectifier circuit at the Rx side, and a closed‐loop control strategy achieving full‐feedforward of the pulsating current is proposed. A proof‐of‐concept prototype of 80 W is built and experimentally validated. Experimental results show that the current ripple at pulsation frequency is reduced by 81.33% and minimum efficiency is increased by 27.9% compared with the case without closed‐loop control, which confirms the accuracy of the theoretical analysis and demonstrates the effectiveness of the proposed power pulsation suppression methods.