A Novel Variable Step-Size LMS Harmonic Detecting Algorithm
This paper proposed a novel adaptive algorithm applied to the harmonic detection that improves the power quality and suppressing grid harmonic. Considering the signal noise ratio (SNR) of the load current is low, the improved algorithm uses the coherent average estimation of the proportion of error signal in the total signal instead of system error to update the step-size, so the step-size only depends on the real system tracking error, and the steady state error is small when the system is close to stable. In addition, the algorithm adopts the time window action of mean estimation to control the influence of past signal on the present one, which produces a big step-size when the system changes. Compared with the fixed step-size least mean square (LMS) algorithm in a grid load current detected by matlab simulation, the improved algorithm has a faster convergence rate, a higher stability precision, and a better performance of anti-noise, the simulation shows the effectiveness of the method.
Long Chen, Yongkang Zhang, Aixing Feng, Zhenying Xu, Boquan Li and Han Shen
J. N. Yang et al., "A Novel Variable Step-Size LMS Harmonic Detecting Algorithm", Key Engineering Materials, Vol. 464, pp. 179-182, 2011