考虑风电不确定性的DFIG模糊自适应辅助调频策略

Fuzzy adaptive auxiliary frequency modulation strategy for DFIG considering wind power uncertainty

风电接入电网使系统惯性降低,伴随风电渗透率的提高,惯性不足对系统频率稳定的负面影响也愈加明显,如何控制风机输出使其辅助电网调频成为亟待解决的问题。首先分析双馈感应发电机(doubly-fed induction generator,DFIG)转子动能提取的动态过程,构建虚拟惯性控制和下垂控制共同作用的综合惯量控制模型;其次,分析频率偏差、风速和渗透率对DFIG转子动能提取的影响及其与综合惯量控制系数的关联关系,提出模糊自适应的参数动态调整策略,使风机能够综合考虑系统频率变化和风速不确定性两个因素,从而自适应调整惯性控制系数,获取更精准的调频功率补偿;最后,通过仿真,验证了所提方法的可行性与有效性。

The inertia of the system is reduced by connecting wind power to the grid. With the increase of wind power penetration,the negative impact of the lack of inertia on the stability of the system frequency becomes more and more obvious,how to control the output of the wind turbine to assist the frequency adjustment of the power grid becomes an urgent problem to be solved. Firstly,the dynamic process of extracting the kinetic energy of the rotor of the doubly-fed induction generator(DFIG) was analyzed,and a comprehensive inertia control model of virtual inertia and virtual droop was constructed to control its participation in system frequency modulation. Secondly,the influence of frequency deviation,wind speed and permeability on the extraction of kinetic energy of the rotor and its correlation with comprehensive inertia control coefficient were analyzed. A fuzzy adaptive parameter dynamic adjustment strategy was proposed,so that the wind turbine could comprehensively consider the system frequency change and the uncertainty of wind power,so as to adaptively adjust the inertia control coefficient to obtain more precise frequency modulation power compensation. Finally,the feasibility and effectiveness of the proposed method were verified through simulation.