抑制载荷的大型风电机组滑模变桨距控制

Sliding-Mode Pitch Control Strategy for Large Wind Turbines to Reduce Loads

随着现代风电机组的不断大型化,风机机械零部件(塔架、桨叶和传动轴等)的柔性不断增大,从而产生较大的疲劳载荷。从控制方法上减少这些载荷将会有效地延长风电机组的使用寿命。对于高风速工作区,传统的桨距角控制采用比例积分线性调节器,且控制目标仅考虑风机转速,该方法并未考虑风机的载荷信息,因而无法有效抑制其载荷。本文基于滑模控制理论,在传统控制目标的基础上,提出了一种降低风电机组载荷的多目标变桨距控制策略,在控制风电机组转速恒定的同时,可有效抑制风机塔架和桨叶的机械振动。采用FAST仿真软件,通过与传统桨距角控制方法相比,验证了所提出控制策略的有效性。此外,所设计的滑模控制策略原理简单、易于实现,且对系统参数变化也具有较好的鲁棒性。

As the modern wind turbines ate becoming larger, the mechanical parts, such as the towers, blades and drive shafts, are more flexible, resulting in large fatigue loads. By reducing such loads through control, the working life of the wind turbines can be extended effectively. In above rated wind speed region, the traditional proportion-integration （PI） control is not able to reduce the load, since its only objective is to regulate rotor speed. To mitigate such problems, a multi-objective pitch control strategy based on sliding mode control theory is proposed for large wind turbines. With the proposed control strategy, the vibrations of the towers and blades can be effectively suppressed while the rotor speed is kept constant. The FAST simulation software is used to verify the proposed method by comparing with the traditional PI control method. The designed sliding mode control strategy is of good robustness to system parameters uncertainty and easy to implement.