The Wind Energy Conversion System (WECS) includes wind turbine, generator, control system, interconnection apparatus. Wind turbines are classified into two types;
1. Horizontal Axis Wind Turbine(HAWT)
2. Vertical Axis Wind Turbine(VAWT)
Modern wind turbine used HAWT with 2 or 3 blades and operate either downward or upward configuration. The generator used for wing energy conversion system mostly of either Doubly fed Induction generator(DFIG) or PMSG type. The PMSG drives achieve very high torque at low speed with less noise and require no external excitation. DFIG have winding on both stationary and rotating part where both winding transfer major power between shaft and grid. Majority of wind turbine manufacturer make use of DFIG for their WECS due to the advantage in terms of cost, weight and size. Multi bridge is a technology where generators, gearbox, main shaft and shaft bearing are all integrated within a common housing. The generator with multi blades concept become cheaper and more reliable than that of the standard one, but it looses its efficiency.
To achieve high efficient energy conversion on these drives, different control strategies can be implemented like Direct Torque Control(DTC), Field Oriented Control(FOC). The wind turbine electrical and mechanical part are mostly linear and modeling will be easier.
The wind energy technological office (WETO)works with industry partner to increase the performance and reliability of next generation wind technology while lowering the cost of wind energy. Efforts have help to increase the average capacity factor from 22% for wind turbine install before1998 to an average of nearly 35% today, up from 30% in 2000. Wind energy cost have been reduced from over 55% per KWh in 1980 to an average of under 3% per KWh in the UNITED STATE today.to ensure future industry growth, wind industry technology must continue to evolve, building on earlier successes to further improve reliability, increase capacity factor, and reduced cost.
A device that converts the wind’s kinetic energy into electrical energy. They are manufactured in a wide range of VERTICAL and HORIZONTAL types.. Array of large turbines known as wind farms, are becoming an increasingly important source of renewable energy and are used by many countries to reduce their reliance on fossil fuels. It allows you to produced 100% clean and free electricity.
HORIZONTAL AXIS WIND TURBINE (HAWT)
Horizontal Axis Wind Turbine have the main rotor shaft and electrical generator at the top of the tower and must be pointed into the wind. Most have the gear box which turns the slow rotation of the blade to a quicker rotation that is more suitable to drive an electric generator. While permanent magnetic direct drive generators can be more costly due to the rear earth materials required, these gearless turbines are sometimes preferred over gearbox generator. Downwind machines have been built, because the do not need an additional mechanism for keeping them in line with the wind. The blades are usually colored white for day time visibility by aircraft and range in length from 20-80 meters. Offshore wind tu rbines are built up to 8MW today and have blade length up to 80 meters.
VERTICAL AXIS WIND TURBINE (VAWT)
Vertical Axis Wind Turbine have main rotor shaft arranged vertically. It is also an advantage when the turbine is integrated into a building because it is inherently less steerable. However there designs produce much less energy averaged over time, which is a major drawback. When the turbine is mounted on a rooftop the building generally redirects wind over the roof and this can double the wind speed the turbine. While wind speed within the built environment are generally much lower than at exposed rural site, noice may be a concern subtypes of the VAWT.