An Adaptive Impedance Matching Network with Closed Loop Control Algorithm for Inductive Wireless Power Transfer

Zhidong Miao; Dake Liu; Chen Gong

doi:10.3390/s17081759

An Adaptive Impedance Matching Network with Closed Loop Control Algorithm for Inductive Wireless Power Transfer

Sensors (Basel). 2017 Aug 1;17(8):1759. doi: 10.3390/s17081759.

Authors

Zhidong Miao¹, Dake Liu², Chen Gong³

Affiliations

¹ Institute of Application Specific Instruction-Set Processor, Beijing Institute of Technology, 5 South Zhongguancun Street, Haidian District, Beijing 100081, China. zhidongmiao@bit.edu.cn.
² Institute of Application Specific Instruction-Set Processor, Beijing Institute of Technology, 5 South Zhongguancun Street, Haidian District, Beijing 100081, China. dake@bit.edu.cn.
³ Institute of Application Specific Instruction-Set Processor, Beijing Institute of Technology, 5 South Zhongguancun Street, Haidian District, Beijing 100081, China. gongchen@bit.edu.cn.

Abstract

For an inductive wireless power transfer (IWPT) system, maintaining a reasonable power transfer efficiency and a stable output power are two most challenging design issues, especially when coil distance varies. To solve these issues, this paper presents a novel adaptive impedance matching network (IMN) for IWPT system. In our adaptive IMN IWPT system, the IMN is automatically reconfigured to keep matching with the coils and to adjust the output power adapting to coil distance variation. A closed loop control algorithm is used to change the capacitors continually, which can compensate mismatches and adjust output power simultaneously. The proposed adaptive IMN IWPT system is working at 125 kHz for 2 W power delivered to load. Comparing with the series resonant IWPT system and fixed IMN IWPT system, the power transfer efficiency of our system increases up to 31.79% and 60% when the coupling coefficient varies in a large range from 0.05 to 0.8 for 2 W output power.

Keywords: adaptive IMN control; efficiency; impedance matching network (IMN); inductive wireless power transfer (IWPT); output power.