2.3 MW direct-drive turbine manufactured in Saginaw

The Northern Power 2.3 MW wind turbine is based on the company’s 100 kW unit and has, says the company, more than 50 years of cumulative field operating experience.

The Northern Power 2.3 MW wind turbine is based on the company’s 100 kW unit and has, says the company, more than 50 years of cumulative field operating experience. Northern Power adds that the permanent-magnet generator and power electronics technology are state of the art. The company has installed and commissioned its first prototype Northern Power 2.3-MW wind turbine. The prototype is owned by Heritage Sustainable Energy and installed at the Stoney Corners wind farm in McBain, Michigan. This prototype turbine, shipped from the new Northern Power factory in Saginaw, Michigan, is the largest direct drive wind turbine in commercial operation in North America.

Using advances in permanent magnet (PM) generators and power electronics, the 2.3-MW unit  is said to represent the next generation in wind turbine technology. Its drivetrain eliminates need for a high-torque gearbox, thereby greatly simplifying the design while removing a frequent area of failure in competing wind turbines. The turbine rotor connect directly to a slow-speed PM generator rotor, without a separate gearbox, main shaft, bearing set, or couplings. This simple design transmits operating loads more directly to the tower, with a minimum number of parts in the load path.

The PM generator eliminates also need for rotor field windings, a field excitation system, and field-circuit slip rings. Eliminating field-circuit losses results in higher overall turbine efficiency, especially when operating at partial load. The proprietary low-speed PM generator is optimized for efficient energy capture with a higher power curve. Other advantage include 20% less weight of magnet materials, 75% fewer stator-coil assemblies, higher power density, and it’s easier to fabricate and assemble

The company adds that the FlexPhase power converter’s design offers high efficiency, high output-power quality, low generator stress, and advanced grid support and ride-through capabilities. The power converter, matched, and optimized for operation with the low speed generator, uses rack-out modules for fast and easy service.

The power converter, in combination with the PM generator, optimizes overall power train performance. This system results in more power delivered onto the grid than from competing designs. The software-enabled advanced topology has 40% fewer IGBTs, 50% fewer capacitors, and a higher power curve than similarly sized turbines.

In addition, the power converter and main transformer are located up-tower. Electricity is converted to medium voltage closer to the point of generation, minimizing long power cable losses between components. This layout results in increased efficiency and lower electrical losses, yielding more revenue-generating power.

Northern Power Systems

northernpower.com