The History and State of the Art of Variable‐Speed Wind Turbine Technology

Abstract

Early wind turbines used for performing mechanical work (pumping, grinding and cutting)

Wind tunnel testing of the DeepWind demonstrator in design and tilted operating conditions

“…From early experiments [1] to their current status as mature supplier of carbon-free energy, commercial wind turbine generators have grown from nearly 50 kW to over 6 MW [2,3] (with projects under development for 10 MW [3,4]). In fact, even though incremental improvements in the power output have continuously been sought through the aerodynamic optimization of rotor blade design [5,6], it has been definitively accepted that major gains in rated power can only be achieved by increasing the swept area of the rotor [7].…”

Future research directions for the wind turbine generator system

“…As compared to the fixed speed wind generation systems, the variable speed wind generation systems produce more power [6,46,47] and provide less stress on the generator shaft, as the shaft speed can vary with the variation of wind speed [48]. The variable speed WECS is also cost effective and provide simple pitch control for the turbine [49].…”

A Market-Based Analysis on the Main Characteristics of Gearboxes Used in Onshore Wind Turbines

“…This work was updated and extended in 2002 [9]. In 2003, Carlin et al [10] studied the capability of operating at variable-speed for different drive train configurations, taking into account then-recent developments on power electronics. Along the same lines, in 2004 Hansen et al [11] classified wind turbines in four configurations according to their speed-control capability (i.e., drive train configuration).…”