Dynamic Complex Impedance Conversion Using Multiple-Input DC/DC Converters

(a) shows the circuit topology of the proposed impedance conversion mechanism. (b) and (c) are the converted impedance plotted on a complex plane ((b) conventional method, (c) proposed method). It can be seen that the proposed method can convert the impedance freely on a "plane" within complex plane, whereas the conventional method can only move within a single "line".

The performance of a wireless power transfer (WPT) system is highly dependent on the complex impedance of the receiver (RX). Therefore, dynamic complex impedance tuning methods are critical pieces for gaining sufficient control over WPT systems. However, prior methods cannot achieve the following three requirements simultaneously: high-frequency (i.e., MHz, GHz) operation, continuous complex impedance tuning, and few additional components. To overcome these challenges, we present a dynamic complex impedance tuning method based on multiple-input DC/DC converters and LC filters. The active operations used in our method are closed in the low-frequency (i.e., after-rectification) region of the circuit; it has the promise of achieving the three above-mentioned requirements.


  1. T. Sasatani, Y. Narusue, and Y. Kawahara, “Dynamic Complex Impedance Tuning Method Using a Multiple-Input DC/DC Converter for Wireless Power Transfer,” Proceedings of IEEE Wireless Power Transfer Conference (WPTC) 2018.
  2. 笹谷拓也,成末義哲,川原圭博,“無線電力伝送のための DC/DC コンバータを用いた複素インピーダンス変換手法についての一検討,” 電子情報通信学会 総合大会,B-21-2,March 2018.