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Motion Technology Powers Wind Energy
Mechanical motion solutions are critical to successful operation of wind turbines
Al Presher, Contributing Editor -- Design News, July 16, 2009
Mechanical motion technology is a key element in the evolutionary path and long-term growth for wind energy solutions. With the design of wind turbines clearly defined, recent developments are focusing on the reliable performance of gearboxes and hydraulic/electric solutions for pitch and yaw control.
"The most significant developments center on increasing the reliability, efficiency and cost of the wind turbines," says Till Deubel, manager for Market Segment Energy for Bosch-Rexroth. "Increasing reliability and efficiency is directly related to techniques for better pitch control, decreasing the stresses on bearings and reducing spikes and other forces on the mast."
Deubel says pitch control is an important motion system used to change the angle of the wind turbine blades and adjust turbine operation for different wind speeds. Pitch motion is controlled using both hydraulic and electric systems and is a key area for innovation.
"Up until now, pitch control has used blades that are pitched at the same angle but now we're looking at individual pitch control," he says. "Each blade can have an individual pitch angle and be adjusted independently based on whether the blade is in an up or down position. This allows the system to compensate for the fact that the wind is stronger in the up position than it is in the down position. By slightly changing the pitch angle, the system can reduce the stress on the bearings of the wind turbine."
According to Dr. Christoph Seifert of Bosch Rexroth AG, offshore wind parks are also an important technology focus, especially in Europe. He says industry has developed a new generation of wind energy plants specifically for use on the high seas which is now ready for series production. Bosch Rexroth has expanded its capacity for producing the large wind-turbine gearboxes generally used in offshore installations by opening a new facility in Nuremberg, Germany. The plant will manufacture around 300 large gearboxes in 2009 for the latest generation of multi-megawatt turbines.
An important development for these offshore locations is software which monitors the condition of the rotor blades and warns the control unit in the case of icing. Condition monitoring systems issue warnings before wear or damage can occur, and allows operators to better plan maintenance measures and increase the availability of the wind energy plants.
"Having enjoyed annual growth rates of up to 30 percent in the recent boom years, wind energy is making somewhat slower progress in 2009," says Seifert. But he says signs point to a return of double-digit growth rates within the next two years.
Production of large gearboxes is critical for the success of offshore applications because these installations normally require the use of larger wind turbines.
