Proposal of Giant Wind Turbine in Deep Floating Offshore and its Dynamic Analysis

风力发电机通常采用变桨距控制，以保持转子转速稳定，避免过载。但是，这种控制方式给海上漂浮式风力涡轮机的运行带来了一定的困难。具体而言，塔架的振荡运动增加，这被称为浮动风力涡轮机的负阻尼。负阻尼问题导致塔架疲劳载荷增加。本研究提出一种新颖的浮式风力涡轮机桨距控制系统的概念，称为RTS控制，以控制涡轮机的旋转和塔架的运动。RTS的概念是通过转子速度和塔桨距角速度来控制叶片桨距。仿真结果与水池试验结果吻合较好。在定常风和规则波条件下的仿真结果表明，RTS控制具有避免负阻尼的能力。同时也证实了RTS控制避免了负阻尼，降低了塔架的疲劳载荷，在脉动风和不规则波中保持了功率。

Wind turbines are usually controlled with the pitch control to keep the rotor speed stable and to avoid the overload. However, the control causes some troubles for the operation of floating offshore wind turbine. Specifically, the tower oscillating motion is increased, which is called as the negative damping of floating wind turbine. Negative damping problem induces the increasing of tower fatigue load. This study describes an original concept, named as RTS control, of pitch control system for floating wind turbine to control turbine rotation and tower movement. The concept of RTS is to control the blade pitch with rotor speed and tower pitch angler velocity. Simulation results are well matched to tank test. Simulations in steady wind and regular wave condition show that RTS control has the ability to avoid negative damping. It is also confirmed that RTS control avoids negative damping and reduces fatigue load of tower maintaining the power in the fluctuating wind and irregular wave.