Interference Risks from Wireless Power Transfer for Electric Vehicles

Authors:

  • Karina Fors
  • Sara Linder
  • Peter Stenumgaard

Publish date: 2020-10-01

Report number: FOI-R--4808--SE

Pages: 31

Written in: English

Keywords:

  • wireless power transfer
  • electrical vehicle
  • interference
  • electromagnetic emission

Abstract

Wireless power transmission (WPT) for electrical vehicle (EV) charging is a relatively new application of wireless energy transfer and its potential impact on other systems has not been investigated in depth. The frequencies for WPT-EV are also used by radiocommunication systems or services. Since WPT-EV is a new technology there is a lot of work going on in the world in evolving the technology itself, but also in investigating interference in other systems and setting emission limits. There is, for example, a working group within the ITU-R that is examining the possible impact of WPT-EV on the radiocommunication services operating in the same or adjacent frequencies. The results in this report are a complement to the work within that group. There are several proposed frequency bands for WPT-EV with different characteristics. From proposed emission limits, comparisons are made with the background noise and a distance within which the interference power exceeds the noise is calculated. Aggregated effects from several WPT-EV systems are also calculated. For a number of radiocommunication services protection distances are derived. The overall conclusion is that radiated emission from WPT may cause non-negligible interference impact on radio-based services at co-location distances ranging from a few tens of metres up to the order of tens of kilometres. The combined effect from several WPT-EV systems can result in an increased noise level for distances up to hundreds of kilometres.