Individual Pitch Control Research And Simulation Of The Offshore Wind Turbine Using Memory-based Control

Wind power generation occupies an important position as a new non-fossil energy in recent years, and the plant scale has been rapidly expanding. As better wind speeds are available offshore compared to on land, offshore wind power contribution in terms of electricity supplied is higher, thus more and more offshore wind turbines have been and will be deployed. Particularly, most of the offshore wind resource potential in many countries is available in water deeper than 30 meters. Therefore, floating offshore wind turbine(FOWT) provides a breakthrough strategy to make full use of the vast sea renewable resourceWith higher flexibility and severer environment, unstable oscillating behavior caused by the strong offshore turbulence would accelerate the components fatigue of the offshore wind turbine. In particular, the floating platform would suffer strong vibration by the wave, which could greatly cause the irreversible damage and increase some unnecessary cost of maintenance. To sustain these high loads, cost of the offshore turbines tends to be heavier and therefore more expensive than their onshore counterparts. Thereby the system require an intelligent and robust control system that not only aims at good quality power control at the above-rated wind speeds but that primarily focuses on the active reduction of fatigue-relevant loads on the turbine components, as caused by wave, wind shear, tower shadow, oblique inflow and turbulence.Since the main objective for the control of wind turbines is to maximize power production while minimizing fatigue loads, individual pitch control is an effective method to regulate the output power and the load in the wind farm, especially when high-speed wind is available or the capabilities of the generators and converters are limited. Individual pitch control offers a highly effective way to ensure the stability both in structure and powerThis paper proposes an innovative method of individual pitch control for FOWT, which uses an advanced memory-based optimal control strategy, to effectively reduce the asymmetric aerodynamic loads and the platform motion. Utilizing the aero-sea dynamics model and combining our original developed simulation software based on FAST, we build the offshore wind turbine model and make and entire wind turbine simulation. Compared to traditional collective pitch control, the individual pitch control which was simulated in Matlab can make a better reduction of the wind turbine fatigue loads. At the last, we introduce the memory-based compensation optimization controller as the core controller of the independent pitch model to make the fatigue loads tracking to 0 to ensure the stability of the wind turbine. Analysis and simulations indicate that the advanced control strategy make a better performance on reducing the fatigue loads including tilt moment and yaw moment, and enhance the stability and reliability of the system.