A Low Cost Ferrite Based Direct Drive Permanent Magnet Generator for Wind Turbines

Greenspur Renewables has developed a new, low-cost, ferrite-based direct drive (DD) permanent magnet generator (PMG) aimed at the offshore wind energy market. DD PMGs are becoming increasingly important for large-scale wind turbines as they remove the need for a gearbox and the high maintenance costs associated with using them. Today, however, all existing large-scale DD PMGs use scarce and expensive rare earth magnets that are sourced almost exclusively from China. The Greenspur DD PMG uses ordinary ferrite magnets which, although less powerful, are 1/30th of the cost by mass of rare earth magnets and can deliver substantial cost savings. Following smaller-scale trials, patent filings and positive feedback from industry, this project will enable Greenspur to specify, build and test a 250kW generator in collaborative R&D partnerships with the Offshore Renewable Energy Catapult (OREC) and with Warwick Manufacturing Group (part of Warwick University). The company’s ultimate objective is to licence its technology for the manufacture of multi MW units for use in the rapidly expanding global offshore wind market.