Design and Implementation of a Multi-Purpose TMR Sensor Matrix for Wireless Electric Vehicle Charging

Xuyang Liu, Chunhua Liu, Wei Han, Philip W.T. Pong

Research output: Contribution to journalArticlepeer-review

62 Scopus citations


A cost-effective technology to monitor the charging performance and detect the coil misalignment and foreign metal objects is indispensable to the commercialization of wireless power transfer on electric vehicle (EV) charging. This paper presents a multi-purpose tunneling magnetoresistive (TMR) sensor matrix, which can monitor the charging performance as well as detect both the coil misalignment and metal objects for wireless EV charging. The magnetic field distribution between coils is measured by the TMR sensor matrix to provide the critical information about charging performance, coil misalignment position, and the existence of metal objects. The mutual inductance and charging power are derived from the measured z-components of the magnetic flux densities. Lateral misalignment position is determined by the symmetry coefficients of the time-varying magnetic field distribution in the range of ±150 mm. Metal objects are detected by the measured magnetic field offsets. In this paper, both 3D finite-element-method modeling and experimental results were presented to demonstrate the effectiveness of the proposed approach. A 14 × 14 TMR sensor matrix with high sensitivity of 80 mV/V/mT was designed and implemented to measure the magnetic field distribution in order to demonstrate the technology.

Original languageEnglish (US)
Article number8550774
Pages (from-to)1683-1692
Number of pages10
JournalIEEE Sensors Journal
Issue number5
StatePublished - Mar 1 2019
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Instrumentation
  • Electrical and Electronic Engineering


  • Tunneling magnetoresistive (TMR) sensors
  • coil misalignment detection
  • electric vehicle (EV) charging
  • foreign metal object detection
  • sensor matrix
  • wireless power transfer (WPT)


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