变步长LMS算法用于谐波电压检测的研究

Research on Variable Step Size LMS Algorithm Adaptive Filter Applies in Harmonic Voltage Detection

单位功率因数(UPF)谐波电流检测法是有源电力滤波器(APF)的一种常用谐波电流检测方法,但在电网电压发生波动时其检测的基波电流会直接受影响,这不能满足实际要求。基于自适应噪声对消理论的自适应滤波器能够较好地实现谐波检测,对此利用最小均方算法(LMS)自适应滤波器用于检测电网基波电压,并将其结合UPF作为改进方法,能够提高传统方法在实际中的检测精度。为了提高LMS算法性能,采用变步长算法,利用相对误差计算步长因子作为新的算法。仿真结果和实验结果验证了改进方法的可行性。

Unity power factor（UPF） harmonic current detection method is commonly used in active power fiher（APF）, but when the grid voltage has fluctuation the fundamental wave current will be influenced directly, which can＇t meet the practical requirements.According to the basic principle of adaptive noise cancellation, the adaptive filter can de- tect the harmonic current correctly.Using an adaptive filter based on least mean square（LMS） algorithm detect the gr- id fundamental wave voltage.Combining the adaptive filter with UPF method as an improved method can improve de- tection aecurary in practice of conventional method.The adaptive filter uses variable step algorithm to improve perfor- mance, and using relative error to calculate step length factor as new method.The simulation and experiment results verify the feasibility of improved method.