Wind Turbines for High Speed Winds – I

PMGs for High Speed Wind Turbines

Aviation technology has developed designs to harness wind energy at high speeds. Modern wind turbines are developed with the motive of utilizing a lot of wind that strikes the blades of the wind mill. While wind is certainly a renewable source of energy, main problem with it is its erratic nature. Power per square meter is the cube of the wind velocity.

Wind Energy measurements

Kinetic energy of the wind is half of (mass * velocity squared).
Amount of energy moving past a point on the wind turbine therefore depends on the velocity

So the power per unit area comes out to be Kinetic Energy * velocity = Cube of ( M*V)
Having power being related to the cube of velocity creates a large difference in generation potential for higher wind speeds.

Wind blowing at 60mph gives 27 times more power than at 20mph.

Wind mill efficiency

Windmills cannot have 100% efficiency since the structure itself impedes the flow of the wind. Many times the efficiency depends on the actual wind speed, in correlation to the wind speed design.

The PMGs for wind are the largest contributor to the efficiency of the turbine. The turbine design and PMGs should be inline with each other to match performance. Hence, custom permanent magnet alternators are the ideal solution once a turbine design is finalized.

Offshore wind

Wind energy is the most popular renewable source of energy worldwide which can meet electricity demands in a sustainable and clean way. Offshore wind is attractive since it has minimal environmental effects. Also the wind speeds at offshore areas is greater which means increased production as power is related to the cube of the wind velocity. On an average the wind speed increases by 10-20% at off shore wind farms. But higher energy yield has to compensate the additional maintenance and installation cost. Hence modern wind turbines which can withstand higher wind speeds and perform efficiently are in great demand.

High Speed Wind Permanent Magnet Generator

There is a demand for wind turbines which start producing at low wind speeds and withstand high wind speeds too. To continually run at high speeds, foundation, tower (mount), blades, and the permanent magnet generator should be designed properly so that they are strong enough to handle the greater mechanical force and electrical output.

The energy in the wind is proportional to the cube of the wind speed, so a wind turbine operating at very high speed will be under a huge amount of stress but also have the opportunity to generate exponentially. Many manufacturers are using fewer blades for a wind turbine which are longer and can withstand higher speeds. Also windings of the permanent magnet generators should not overheat under this stress. Hence permanent magnet alternators are built to withstand higher wind speeds so that the efficiency of the wind mills is not affected and no damage is done to the internal parts of the generator. All these measures lead to the development of a turbine which withstands speeds which are higher than average. These models are essential since the power obtained from these high speed winds is enormous and should not be wasted. Power densities are increased if we successfully utilize these high speed winds which are in abundance at many off shore and high latitude areas.