Excerpt from Baidu Encyclopedia:
Direct-drive permanent magnet wind turbines have the following advantages:
1. High power generation efficiency: direct-drive wind turbines do not have gearboxes , reducing transmission losses and improving power generation efficiency, especially in low wind speed environments, the effect is more significant.
2. High reliability: The gearbox is a component with a high frequency of failures in the operation of wind turbines. Direct drive technology eliminates the need for gearboxes and accessories, simplifies the transmission structure, and improves the reliability of the unit. sex. At the same time, the unit operates at low speed, has fewer rotating parts, and has higher reliability.
3. Low operation and maintenance costs: The use of gearless direct drive technology can reduce the number of wind turbine parts and components, avoid regular replacement of gearbox oil, and reduce operation and maintenance costs.
4. Excellent grid access performance: The low voltage ride-through of the direct-drive permanent magnet wind turbine causes the voltage at the grid connection point to drop, and the wind turbine can operate continuously on the grid within a certain voltage drop range. , thereby maintaining the stable operation of the power grid.
The direct-drive wind turbine does not have a gearbox, and the low-speed wind wheel is directly connected to the generator. All harmful impact loads are also borne by the generator system, which requires high requirements on the generator
The demand is very high. At the same time, in order to improve the power generation efficiency, the number of poles of the generator is very large, usually around 100 poles. The structure of the generator becomes very complex and bulky, and the whole machine needs to be hoisted and maintained. And the use of permanent magnet materials and rare earths adds some uncertainties.
Large-scale magnetic power generation exists, and CCTV has also reported it. However, I personally believe that according to the law of conservation of energy, if there is no external force, large-scale magnetic power generation consumes magnetic force, and the permanent magnets will demagnetize regularly. Needs to be remagnetized. This is full of uncertainty for its popularization.