Double-sided rotor technology for iron-cored permanent magnet wind generators: An evaluation

In this article a double-sided rotor technology for an iron-cored permanent magnet direct-drive wind generator is evaluated. The evaluation is based on the finite element and laboratory test results of an optimum designed 15 kW iron-cored permanent magnet wind generator. Aspects such as mass, performance quality, cooling characteristics and efficiency, amongst others inherent in such a study are investigated. Although the double-sided rotor permanent magnet wind generator requires nearly twice the magnetic volume compared to the conventional single-sided permanent magnet wind generator, its active mass turns out to be less than that of both the single-sided rotor generator and an air-cored permanent magnet wind generator of the same power level. The double-sided rotor topology furthermore becomes attractive because of its inherent cooling characteristics, which are evident in its low operating temperatures.