Modeling and loading compensation of a rotary valve-controlled pitch system for wind turbines

Abstract

A rotary valve-controlled pitch system is proposed to regulate the generator power and smooth power fluctuations for a wind turbine. Design details and dynamic modeling of this pitch system are presented and analyzed. A practical loading compensation approach is synthesized and involved in the pitch system to compensate for the external uncertain pitch loads. The proposed pitch system and loading compensation approach have been experimentally evaluated in terms of generator power smoothing and control accuracy. As demonstrated by the comparative experimental results, the proposed pitch system can be used to significantly smooth the generator power fluctuations and hence to improve the power quality as compared with a servo valve-controlled pitch system under the same operating conditions. The loading compensation approach can also be used to significantly attenuate the effects of external pitch loads and improve the robustness and reliability of the pitch system. The proposed pitch system features good control accuracy and cost-efficiency and hence is attractive for applications in modern largescale wind turbines.

中文概要

目的

风速的随机瞬变容易导致风电机组输出功率的大幅波动。本文拟采用数字旋转阀控马达变桨距技术,以有效地提高各种风况下的风电机组输出功率平滑控制的性能,并采用变桨载荷补偿的方法,以提高变桨距控制的精度和抗干扰能力。

创新点

1. 提出数字式旋转阀控马达变桨距的控制技术,推导得出变桨距控制的模型;2. 提出变桨距载荷补偿的控制方法,以提高变桨距控制的精度和鲁棒性;3. 搭建实验台,并与伺服阀控马达变桨距进行功率平滑控制的对比性研究。

方法

1. 通过理论推导,构建旋转阀控马达变桨距的机理模型,得到输出桨距角与输入控制信号之间的定量关系;2. 通过对比性实验分析,验证旋转阀控马达变桨距在输出功率平滑控制方面的高效性。

结论

1. 相比于伺服控马达,数字式旋转阀控马达变桨距能更有效地平滑风电机组的输出功率,提高输出功率的稳定性和质量;2. 变桨载荷补偿的方法能更为有效地提高旋转阀控马达变桨距控制的精度、响应速度和鲁棒性。