Wind Turbine Advantages And Disadvantages

For a fixed speed wind turbine, where ω is constant, which corresponds to a particular wind speed. For all other wind speeds the efficiency of the turbine is reduced [3]. The aim of variable speed wind turbines is to always run at optimal efficiency, keeping constant value of tip speed ratio ‘λ’ that corresponds to the maximum Cp, by adapting the blades velocity to the wind speed changes. Hence, variable speed wind turbines are designed to operate at optimum energy efficiency, regardless of the wind speed [2]. The conversion efficiency of variable speed wind turbine generator is maximum due to variable speed operation. Therefore, variable speed wind turbines are preferred over constant speed wind turbines. The key advantages of variable speed generators (VSGs) compared to fixed speed generators (FSGs) are [1]:

Cost effective and provide simple pitch control: The controlling speed of the generator (frequency) allows the pitch control time constants to

The largest rated capacity for the commercially available wind turbines based on DFIG has capacity up to 5 MW from Repower [8]. The DFIG wind turbine generator system offers the following advantages: Economic: The power electronics circuits used in DFIG are simple. The rating of the power electronic converter typically 25 to 30 percent of the generator capacity, which makes DFIG concept attractive and economical [8]. Improved system efficiency It is possible to control power factor at lower cost because the DFIG system basically operates similar to a synchronous generator with four quadrant converter and induction machine. DFIG has a complete control of active and reactive power. A partial scale four quadrant electronic converter in the rotor circuit enables in control of active and reactive power of the