Now the company is entering the multi-megawatt market with its new 2.2MW direct-drive turbine. The Northwind 2.2 incorporates features such as a permanent-magnet generator and FlexPhase full power converter. Both components were developed in-house.
The turbine concept has been developed with a focus on transport and serviceability. The pitch-controlled variable speed machine further features a 93-metre rotor diameter in order to optimise energy yields at high altitudes and under high-turbulence wind conditions.
Troy Patton, president of NPS's utility-scale wind division, says the Northwind 2.2 product history dates back to 2000, when the US Department of Energy (DOE) awarded NPS a product development grant.
"Supported by this funding, we started developing a 1.5MW technology demonstrator turbine that was extensively tested at DOE's facilities during 2005. Based on these positive outcomes the turbine, generator and power conversion system were further developed and up-scaled to the current 2.2MW power rating," Patton says. He adds that, during the process, the NPS research and development team focused on achieving power generation under lowand medium-wind speed conditions.