Study the Types of Electrical Generators Used in Wind Turbines

Generation of electricity from renewable sources has grown substantially owing to active governmental stimulation programs in many countries. Wind energy is considered one of the most efficient types of renewable energy. In wind turbines there are many types of generators can be used. This article presents a comparative analysis of all types of electrical generators that are used in wind energy in addition to determining advantages and disadvantages for it. Synchronous generators can be a good choice for variable speed operation since it has low rotational synchronous speed that produces the voltage at grid frequency. Permanent magnet synchronous generators (PMSG) do not require gearbox but PMSG has a big size so it can be a suitable selection for small wind turbines. Squirrel cage induction generators (SCIG) suitable for variable speed operations since grid is absolutely decoupled. One of disadvantage of SCIG is that gears are unavoidable. Doubly fed induction generators (DFIG) Compared with the earlier generator type it is simpler in mechanical design and electrical structure, but gearboxes and brushes are still essential. To overcome disadvantages of DFIG, Brushless Doubly fed induction generators (BDFIG) be consider as a wise decision because of the power of bidirectional converter is low in BDFIG, in addition to absence of brushes which reduces needing for periodic maintenance operations, Moreover, better investment for the wind turbine. This research has studied modes of operation for induction machines. Finally, advantages and disadvantages for each type of generators are summarized.