The most common magnet material used in permanent magnet generators is neodymium iron boron (NdFeB). Some key properties that make NdFeB well-suited for permanent magnet generators:

– High magnetic flux density – NdFeB magnets can produce significantly stronger magnetic fields compared to other permanent magnet materials. This allows for higher power density generators.

– High coercivity – NdFeB has a strong ability to resist demagnetization. This allows it to maintain a strong magnetic field even in high-temperature environments commonly found in generators.

– Decent temperature stability – NdFeB can operate reasonably well at temperatures up to 120–150°C before losing significant strength.

– Abundant raw materials – NdFeB magnets are made from relatively abundant neodymium, iron, and boron. Other high-performance magnets use rarer elements.

– Cost-effective – Less expensive compared to other high-field strength magnets like samarium cobalt.

– Can be shaped – NdFeB is available in a wide variety of geometries optimized for different generator configurations.

So in most cases, the exceptional magnetic properties combined with reasonable cost makes NdFeB the preferred choice for high-efficiency permanent magnet generators. The development of NdFeB in the 1980s is what enabled compact, high-power permanent magnet generators.

What are the advantages of using NdFeB magnets in wind turbine generators?

Here are some of the main advantages of using neodymium iron boron (NdFeB) magnets in wind turbine generators:

– High power density – The strong magnetic fields produced by NdFeB magnets allow for very compact and lightweight generator designs. This results in more power output for a given size.

– High efficiency – The high magnetic strength enables efficient conversion of mechanical wind energy into electrical energy. Less energy is lost compared to generators with weaker magnets.

– Low maintenance – Since they are permanent magnets, NdFeB generators don’t need external excitation currents. This eliminates slip rings, brushes, and field windings that require maintenance.

– Better low wind speed output – Strong NdFeB fields improve low rpm performance. This allows electricity generation at lower wind speeds.

– Temperature resistance – NdFeB magnets retain their magnetic properties better at higher temperatures than other permanent magnets. This improves reliability.

– Corrosion resistance – Proper coating allows NdFeB magnets to resist corrosion, improving durability and lifespan.

– Cost-effectiveness – The high magnetic energy density of NdFeB provides more value per unit cost compared to other magnet types.

– Wide availability – Mass production and widespread use make NdFeB easily obtained from many suppliers.

The combination of small size, high efficiency, and reliability provided by NdFeB magnets has made them the preferred choice for direct drive and hybrid permanent magnet wind turbine generators. Their properties are well suited to extracting energy from inconsistent wind patterns.