大型风电机组的功率曲线自寻优控制策略

Self-optimizing Power Curve Control Strategy for Large Scale Wind Turbine

大型风电机组在额定风速以下一般采用最大功率曲线法进行机组的最大功率跟踪控制,但机组的最大功率曲线一般通过实验获得,很难保证精度。为优化风电机组在低风速区域对风能的利用率,提出了基于微分跟踪器的功率曲线自寻优控制策略。采用微分跟踪器提取出机组转速和机械功率的微分值,并由此判断实际功率曲线与最大功率点之间的位置关系,然后采用三维模糊控制器对功率曲线的系数进行实时调整。以2MW双馈风力发电系统为基础,在Bladed仿真环境中对自寻优控制策略进行了仿真研究。仿真结果表明所提出的自寻优控制策略对机组参数如功率特性或转矩特性等依赖性较小,在风速变化的情况下能够对机组功率曲线的系数进行实时的修改,并有效地将机组的功率曲线调整到最大功率曲线的位置,从而证明了该策略的正确性和可行性。

The power signal feedback is usually used to track the maximum power point for large scale wind turbines control when the wind speed is below the rated speed.However,the maximum power curve of wind turbine is generally obtained from field experiments,which is hard to assure accuracy.Consequently,we proposed a strategy of self-optimizing power curve control based on tracking-differentiator to improve the efficiency of wind turbine operation in low wind.The differential signals of rotor speed and mechanical power are extracted by the trackingdifferentiators and used to determine the position relation between the actual power curve and the maximum power point.A three-dimensional fuzzy controller was designed for the real-time regulation of the coefficient of power curve.Based on a 2MW doubly-fed wind power generation system,the self-optimizing power curve control strategy was simulated in the Bladed simulation environment.Simulation results show that the proposed method has comparatively small dependence on the parameters of wind turbine such as the power characteristic or torque characteristic.The method can regulate the coefficient of the power curve real-timely and adjust the actual power curve to the position of maximum power curve effectively when wind speed changes,verifying the correctness and feasibility of the control strategy.