The magnetic attraction of wind turbine generators
The quest to improve wind turbines is sparked by the necessity to make the overall production of clean energy systems more valuable. In order to do so, reducing production costs is essential. Moreover, a more efficient system will be needed and this would require the minimization of noise levels-especially at the partial load capacity of turbines. Other improvements required are high partial load efficiency at lower cost, a compact, light and attractive outer design and support for weak power grids through the advanced converter control concept. With these aims, the PERMAGWIT conducted its initial research phase. The research resulted in many considerable advancements, one of the more impressive being the omission of the gearbox and the introduction of permanent magnets. This lead to an increased partial-load efficiency and hence, to an enlarged energy production. Additionally, the neodymium-iron-boron magnets impart better magnetic qualities as well as high chemical stability which is important for long term reliability. Due to the outer rotor concept, another advantage gained is the fact that the magnets can be cooled naturally by the surrounding wind. Furthermore, this outer rotor concept has lead to the reduction of both length and weight of the generator due an increase in the air-gap diameter. Also, the generator housing is a fully enclosed construct to prevent insulation problems related to the stator winding and corrosion of the magnets. The generator's overall inductance has also been reduced due to the optimised pole geometry and this has lead to a decreased load angle but an increased power factor. Since wind turbines are such finely engineered systems, altering one aspect of its construction, may in some cases, require the alteration of other features. Such was the case with the PERMAGWIT project whose developments may not necessarily be the answer to all wind turbine issues, but at least it's blowing in the right direction.
