DESIGN AND TESTING OF A 250 kW FERRITEBASED AXIAL FLUX PERMANENT MAGNET FOR APPLICATION IN WIND POWER GENERATION

Abstract

This paper presents the construction and testing of a ferrite-based axial flux permanent magnet machine (PMg) for applications in wind power generation. This technology offers significant levelized cost of energy reductions via capital expenditure and operating expense savings - a crucial objective for the offshore industry. The direct-drive (DD) PMG technology uses ferrite magnets to create the magnetic field, which is a significant source of cost reduction. The use of ferrite could also eliminate an industry wide reliance on neodymium iron boron, the scarce and expensive rare-earth magnet used in existing designs. Another benefit of using ferrite-based design is that it is less sensitive to the cooling problems that currently face existing DD-PMGs. Further technical advantages come in the form of magnetically balanced axial design, optimized magnet and aluminium/copper ratio, insensitivity to air gap and cogging elimination. This paper details aspects of design, construction, thermal performance and testing of a nominal 250 kW power rating prototype.