基于改进型自适应算法的谐波检测及其性能研究

Harmonic detection based on improved adaptive method and its performance study

通过对有源电力滤波器基本自适应谐波电流对消检测方法的研究,指出了基本自适应方法存在检测精度和动态响应之间的矛盾,证明了基本自适应系统是一个关于中心角频率对称的陷波器。理论推导证明了由于系统权向量不为一个恒定的值,导致该系统不能准确提取谐波电流。在此基础上提出了一种改进型模拟自适应对消检测方法,讨论了改进型自适应系统的稳定性。改进后系统是通过加入一个低通滤波器减小了陷波器参考角频率附近的带宽,系统实质上是一个关于中心角频率不对称的陷波器。该方法可在保证动态响应的前提下兼顾系统的检测精度。理论推导和仿真实验均证明了该方法的实用性。

The harmonic current detection based on basic adaptive cancellation method for active power filter is studied and the contradiction between detection accuracy and dynamic response is pointed out.It is proved that the system is a symmetric notch filter at center angular frequency.Since its weight vector is not constant,the system could not detect harmonic current accurately.An improved adaptive cancellation detection method is proposed and the stability of the improved system is discussed.A low-pass filter is added to reduce the bandwidth near the reference angular frequency and the system becomes an asymmetrical notch filter.The improved method can take account of both detection accuracy and dynamic response.Its practicability is verified by the theoretical analysis and simulative experiments.