Z-Impedance Compensation for Wireless Power Transfer Based on Electric Field

Liang Huang, Aiguo Patrick Hu, Akshya Kumar Swain, Yugang Su

Research output: Journal PublicationArticlepeer-review

84 Citations (Scopus)


Capacitive power transfer (CPT) has been investigated as an alternative wireless power transfer technology based on electric field coupling. The coupling interface of CPT is formed by a pair of "capacitors" in series with the power source and load. The effective capacitance ranges from tens to a few hundreds of picofarads, yielding high impedance. Therefore, in most CPT systems, a tuning inductor is connected in series with the coupling interface for circuit compensation and power transfer capability enhancement. However, this compensation method suffers from high voltage spikes from the inductor if the secondary side load is removed suddenly causing electrical and health hazards. To address the issue, this paper proposes a CPT system based on a Z-impedance compensation network with inherent open-circuit and short-circuit immunity. It also has the voltage boost capability as a Z-source inverter. Its operating principle is described and a set of design equations are given. Both simulations and experimental results from a 5 W low power design have demonstrated that the proposed compensation method using the Z-impedance matching network exhibited open-circuit and short-circuit immunity, could boost up the output voltage by 50% with power efficiency exceeding 80%.

Original languageEnglish
Article number7457707
Pages (from-to)7556-7563
Number of pages8
JournalIEEE Transactions on Power Electronics
Issue number11
Publication statusPublished - Nov 2016
Externally publishedYes


  • Capacitive power transfer
  • Z impedance
  • compensation
  • wireless power transfer

ASJC Scopus subject areas

  • Electrical and Electronic Engineering


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