Potential Interference from Wireless Power Transfer Systems

The SARL made a presentation to members of the SABS Technical Committee, TC-73, on the potential interference that Wireless Power Transfer systems for the charging of electric vehicles may cause on the HF bands.

The committee discussed the possible implications and supported the SARL call to place the matter formally on the agenda of Work Group 1 which will further review the potential of interference and report back at the next meeting of TC-73 which will be held at the end of May.

The May TC-73 meeting will formulate South Africa's official position when the matter is discussed at the CISPR meeting in China in mid-October this year.

Hans van de Groenendaal who made the presentation said that he was encouraged by the positive support during the discussion.

While the number of electric vehicles in South Africa is currently low, the potential of a rapid increase is great. Shell recently announced that it will be installing charging facilities on a large number of their forecourts and two major motor vehicle manufactures have already installed charging system in their showrooms.

Some discussions in CEPT suggest that the existing spurious emission limits for inductive SRDs are appropriate but these were developed on a wholly different set of assumptions about duty cycle, location and whether victim and emitter share the same frequency.
These standards are not appropriate for WPT which has a high duty cycle with power up to 22 kilowatt, located in residential areas and its harmonics are likely to be spread across a band of frequencies.

The South African Radio League - http://www.sarl.org.za/