变速恒频风力发电系统风机转速非线性PID控制

Nonlinear PID Rotating Speed Control of Variable Speed Constant Frequency Wind Turbine System

针对变速风机非线性强、转动惯量大、转轴机械阻尼随转速变化的特点,提出了变速恒频风力发电系统风机转速非线性PID(nonlinear-PID,NLPID)控制策略,仿真研究表明,非线性PID控制响应快,超调小,受系统参数变化的影响较小,控制精度高,具有一定的适应性和鲁棒性。此外,该文设计了基于模糊规则切换的模糊PID-PID双模变桨距控制器,在此基础上对变速恒频风力发电系统在全风速范围内的运行进行了数字仿真研究。在高于额定风速时,通过变桨距控制器调节桨距角,系统能较好地将功率限制在额定值附近;在低于额定风速时,通过模糊推理,系统能够在免测风速的情况下给出转速参考信号,实现最大风能捕获或恒转速运行。

Strong nonlinearity, big moment of inertia and changing mechanical damping with rotating speed are the characters of wind turbine. A new nonlinear-PID （NLPID） controller for rotating speed control in variable speed constant frequency （VSCF） wind turbine system is proposed. Fast response, small overshoot, high precision, strong adaptability and highly robustness are obtained by the proposed strategy. A fuzzy PID-PID dual-mode variable pitch controller is designed. Based on these, the VSCF wind turbine system running in the whole working wind speed range is studied by simulations. With the action of fuzzy PID-PID dual-mode controller, system can keep the rated output power above rated wind speed; when wind speed is under the rated value, system can estimate the optimal rotating speed without test of wind speed by fuzzy controller and reach the maximum wind-energy capturing or keep the rotating speed constant.