大型变速恒频风电系统的建模与仿真

Modeling and simulation of variable-speed wind generator system with large capacity

针对兆瓦级变速恒频风力发电系统,基于Matlab/Simulink建立了包括风机、传动齿轮、双馈发电机在内的大型风电系统的整体动态数学模型。传统的最大风能捕获算法往往基于最优功率曲线和部分风机参数已知,当上述参数未知或出现扰动时,风电系统的效率会严重降低。针对此不足,基于所建模型设计了变步长最大风能捕获控制器,该控制器采用矢量控制算法,实现了发电机输出有功和无功功率的解耦控制;针对有功功率控制,控制器根据发电机输出转速扰动时,相应输出有功功率的变化变步长地调整系统输入,直到系统运行到最大风能点。仿真结果验证了风电系统模型的正确性以及控制器的有效性。

A whole dynamic model of a MW-class variable-speed wind generator system is presented with Matlab/Simulink,including wind turbine,drive train and doubly-fed generator. The traditional MPPT（Maximal Power Point Tracking） algorithms are usually based on the knowledge of the maximal power curve and partial parameters of the wind turbine. The efficiency of wind generator system reduces deeply when the above curve or parameters are unknown or changing. A ＂variable- step searching controller of MPPT＂ is designed based on the model. The controller uses vector control strategy to realize the decoupled control of active and reactive power outputs and adjusts the system input with a variable step according to the variation of active power output when rotational speed perturbation takes place. Simulation results show that,the model is correct and the controller is valid.