Measuring air gap width of permanent magnet linear generators using search coil sensor
2007 (English)In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 101, no 2, 024518- p.Article in journal (Refereed) Published
A concept for a wave power plant is being developed at the Centre for Renewable Electric Energy Conversion at the A˚ngström Laboratory at Uppsala University. The concept is based on a permanent magnet linear generator placed on the seabed, directly driven by a surface following buoy. Critical for the survival of the generator is that the air gap between the moving and static parts of the generator is constantly fixed at the designed width to prevent the moving and static parts from connecting during operation. This paper shows the design and evaluation of an inductive sensor for measuring the air gap width during generator operation. In order to survive during years on the seafloor inside the wave power plants, the sensor has deliberately been chosen to be a passive component, as well as robust and compact. A coil etched on a printed circuit board, i.e., a search coil, was the chosen basis for the sensor. The sensor has been tested on an existing test rig of a wave power plant and the results have been compared with finite element simulations.The results show that a search coil magnetic sensor etched on a printed circuit board is a suitable concept for measuring the air gap width. Experimentally measured and theoretically calculated sensor signals show very good agreement. The setup has a sensitivity of +/-0.4 mm in the range of 4-9.5 mm air gap. The potential for future improvements of the sensitivity is considerable.
Place, publisher, year, edition, pages
2007. Vol. 101, no 2, 024518- p.
High-current and high-voltage technology: power systems; power transmission lines and cables, Electric motors, Spatial dimensions, Sensors ; remote sensing, Finite-element and Galerkin methods
Engineering and Technology
IdentifiersURN: urn:nbn:se:uu:diva-94990DOI: 10.1063/1.2403964ISI: 000243890800148OAI: oai:DiVA.org:uu-94990DiVA: diva2:169033