大型风力发电机转矩LQR控制及载荷优化

Load reduction for large-scale wind turbine based on LQR torque control

传统的风力发电机的控制方法在高于额定风速时,采用变桨距限制风轮转速,同时采用恒定的转矩控制电机转矩。恒定的电机转矩导致风力发电机传动链扭转阻尼比很小,使传动链扭矩大幅度的波动,甚至引起风力机结构的共振。针对该问题,建立了传动链基于状态空间的线性化模型,采用LQR(Linear Quadratic Regulator)方法设计风力发电机的转矩控制器,将传动链一阶扭转模态对应的闭环极点向虚平面的左侧移动,实现对传动链进行动态加阻。采用FAST的计算模块获得了风力发电机传动链的线性化状态空间模型,采用Matlab7.1/Simulink进行控制器设计并与FAST进行联合仿真。结果表明提出的控制方法有效地提高了传动链的阻尼,降低了风力发电机组关键零部件的载荷。

Traditional way of control for wind turbine employs a constant torque for generator above rated wind speed while using pitch control to regulate rotor speed. It results in a quite low damp ratio of the drive train torsional mode which would invoke large fluctuation in drive train torque, and even oscillate the structure. In concern of this problem, the paper designs a linear quadratic regulator （LQR） to dynamically control the generator torque. By moving the closed-loop poles corresponding to the first order drive train torsion mode further to the left in the complex plane, the generator torque controller adds active damping to this mode. After extracting linear state space model of the drive train, Matlab7.1/Simulink is used to design the controller and FAST is engaged in the co-simulation. The results show that the proposed control mean successfully adds damping to the drive train and reduces loads of the key components of wind turbine.