Glossary of Wind Energy Terminology

Double Fed Induction Generator (DF) — sometimes referred to as DFIG — has been widely used technology in wind turbines for ten years in thousands of commissioned wind turbines. It is based on an induction generator with a multiphase wound rotor and a multiphase slip ring assembly with brushes for access to the rotor. Recently, designs without the brushes have been introduced.

Full Conversion (FC) drive train — the wind turbine gearbox is protected because the generator is not connected to the grid. It is more efficient than the DF and is a redundant system which provides protection in case of a one converter’s failure. As the turbine generator is now decoupled from the grid, the frequency and voltage at which the generator operates is independent of the constant voltage / constant frequency of the grid and this permits variable speed operation.

Direct Drive (DD) technology — a smart, straightforward design that eliminates the need for gearboxes. With fewer moving parts, DD technology can reduce maintenance costs and provide higher wind turbine availability. However, DD machines are typically known to be heavier and more expensive in manufacturing than geared wind turbines.

SuperGEAR™ (SG) drive train technology — this is AMSC Windtec’s latest patented technology which provides the wind turbine’s generator direct connection to the utility grid. With no converter or transformer required, it provides the best possible power quality available on the global market. This high-technology enables smaller and lighter nacelles with higher and more stable efficiency and thus reliability, characteristics that are crucial for offshore wind installations.