Research On Pitch Control Strategy With Wind Turbine Loads

With the constant renewal and development of wind power technology, wind turbinegradually to the development of large-scale, lightweight direction. How to get the desiredpower quality and reduce the wind turbine loads effectively, which is one of the hot spots oftoday’s wind turbine control technology research. The development of large-scale, lightweightof wind turbine increases the flexibility of parts and reduces the natural frequency values ofwind turbine, which makes wind turbine systems at the low damping and easier to stimulatethe resonance phenomenon, which bring great harm to safety and stability to the operation ofwind turbine. Meanwhile, wind turbine bears static loads and dynamic loads during operation,such as the aerodynamic loads, gravity loads, and gyroscopic inertial loads, which make thewind turbine units suffered more complex loads, wind turbine in the pitch process, due to theincrease of the weight of the wind wheel，resulting in rotating inertia increase, when the pitchaction occurs, the pitch control system will give wind turbine a lot of mechanical stress,these mechanical stress brought great damage to the wind turbine, a serious impact on the lifecycle of the wind turbine. Therefore, the control and optimization of wind turbine loads is oneof the hot spots of today’s wind turbine control technology research.MW-scale wind turbine is researched in the paper, to reduce the loads of wind turbine asthe goal, in-depth study on wind turbine pitch control strategy, and proposed a "co-ordination"variable pitch control methods based on the characteristics of the wind turbine itself withoutincrease wind turbine cost. In order to verify the correctness and feasibility of control strategy,various operating conditions of wind turbine is simulated in this paper, wind turbine loadsdistribution under various working conditions is analyzed and the effectiveness and feasibilityof the control strategy is verified through establishing a wind turbine model by GH Bladedsimulation software in this paper.The paper’s specific organization arrangements are:According to the needs of wind turbine control research, the characteristics and structureof the wind turbine was analyzed, and a system model was established by GH Bladed and itsoperating parameters were checked to verify the correctness of the model.For tower side-side vibration of wind turbine and drive chain torsion vibrationphenomenon, the tower side-side vibration acceleration feedback and damping filter wereintroduced into in the torque controller, to increase the tower and drive chain the effective damping by increasing in additional torque and the correctness and feasibility of the controlstrategy were checked by simulation experiment.For the phenomena of tower fore-aft vibration, the acceleration feedback of towerfore-aft vibration was introduced in the pitch controller, and verified the correctness of thecontrol strategy by GH Bladed Modeling and Simulation. The introduction of vibrationacceleration feedback tower fore-aft effectively increased the effective damping of the windturbine tower, reduced the vibration phenomena of the tower.In order to can effectively control the power, and can effectively reduce the loads of thewind turbine, pitch control strategy based on power and loads co-ordination is used to meetthe power output as much as possible to reduce wind turbine loads and through experimentsverify the correctness of the coordinated control strategy to meet the control requirements.