One trend in wind motors and drives is an increasing demand to refine overall turbine design for lower cost and higher availability. Also, instead of buying the gearbox and motor separately from different manufacturers, some companies offer them packaged together. Lastly, requirements for pitch control are increasing in larger, more powerful turbines.

Pitch control is a key safety system in turbines. Ray Opie, senior project engineer at Moog, says their customers are looking to refine over all turbine design for optimized cost and availability. “They want to increase the hours of the day the turbine runs, thereby producing more power and achieving better cost-effectiveness,” he says. “Also, lower costs are making things thinner and more slender, which means the pitch system is more dynamic.”

This leads to another trend concerning increased requirements for pitch-system performance. “This seems to be across the board,” Opie says. “Blade sensing systems at the root of each blade help increase pitch control and allow using motors and drives to turn the blades, improving reliability and safety.” These load sensors molded into the blades allow adjusting pitch as needed for best rotor loading and to avoid overloads.

Opie says the industry is also starting to look at the methodology used elsewhere with reliability assistance. Reliability is especially important in wind turbines. “As with aircrafts, things can’t go wrong,” he says. “They must always do what they need to do. There are many tools from other industries to determine reliability in wind.” Electric pitch actuators often consist of a gearbox and either an ac or dc motor. To further optimize reliability, Moog offers the gearbox and motor as a package, instead of having to purchase them separately from different manufacturers.

Also, as in most industries, the motors and drives industry is looking for ways to reduce maintenance and replacements. Network connections in hydraulic pitch controls have the bandwidth to accommodate almost any practical level of control signals, plus inputs from sensors that monitor valve and actuator performance. By identifying small degradations in performance, sensors and software in today’s systems can schedule preventive maintenance and even component replacement during scheduled downtime.

Furthermore, Greg Schulte, president of Bonfiglioli USA, says industry attention is on nacelle weight reduction, reduced maintenance, and faster installation. “This has inspired our company to design a compact line of multistage, planetary gear motors for yaw control that comprise all these features,” he says. The motors are more compact, 8% lighter, and have 11% fewer parts, which simplifies maintenance with longer service periods. Opie says Moog is also focusing on component enhancements to offer the simplest, most reliable product.

WPE