Researches of a controller for reducing load of driving chain in wind turbine based on h· control

Large parallel network wind turbines generate power by transfer torsional power, which is captured by wind shroud and accelerated by driving chain, to electric machine rotor. The drive system of variable speed wind turbine mostly uses flexible connection. That kind of connection adjusts exciting current and operating condition when wind speed and rotary speed change. Thus, it is one of the main reasons of unstable load of driving-chain causing damages of gear case and main bearing. It also has a strong impact on generator´s life-span. Therefore, reducing unstable load of driving-chain and tensional vibration are always the problems in wind turbine design. This paper brings forward an approach based on H∞ full state feedback control to reconstruct a needed load-damping-controller in wind generators. The reconstruction process is built on a sensitivity function aiming at inhibiting unstable torsion. The function is based on full state feedback factor K. Theoretical simulation results testify the feasibility of the new approach in reducing unstable load of driving-chain.