摘要:电网电压不平衡时,传统对称分量法,会将电流检测量中的毛刺或高次谐波等干扰信号放大,导致使用对称分量算法分离正负序分量存在较大误差,从而影响基于正负分量法控制策略的控制效果,论文首先分析传统对称分量法在信号检测存在毛刺和谐波时的影响,提出改进的瞬时对称分量方法,改善正负序信号量分离的检测精度,并通过改变离散算法的计算步长,抑制毛刺干扰和谐波分量对正负序分量分离的干扰,提高正负序分量的分离精度,并抑制发电系统的整体谐波含量,论文最后建立了DFIG基于负序同步旋转轴系下的数学模型,研究了采用改进的瞬时对称分量法抑制DFIG负序电流的控制策略,并通过系统仿真,验证了论文所提出的改进瞬时对称分量法的正确性。 关键词:风力发电;双馈感应发电机;电网电压不平衡;对称瞬时分量法
Abstract: When the power grid voltage unbalance, the traditional symmetrical component method can amplify the interference signal such as burr or higher harmonic in the current detection, resulting in a large error in the separation of positive and negative sequence components using the symmetrical component algorithm, and the control effect of the control strategy based on the negative component method is affected. This paper first analyzed the influence of the existence of burr and the harmonics in the signal detection of the traditional symmetrical component method, proposed an improved instantaneous symmetrical component method, improved the detection accuracy of the positive and negative sequence signal, and reduced the interference of the positive and negative sequence components by changing the computation step of the discrete algorithm, and improved the negative sequence separation accuracy and suppress the overall harmonic content of the powerd system. At the end of this paper, the mathematical model of DFIG based on negative sequence synchronous rotating shaft system was established. The control strategy of DFIG negative sequence current was studied by using the improved instantaneous symmetrical component method, and the correctness of the proposed method was verified by system simulation. Key words: wind power generation; doublyfed induction generator(DFIG); unbalance grid voltage; symmetrical instantaneous component method |