A New Harmonic Extraction Method for Estimation of the Reference Compensation Current in Shunt Active Power Filters

Abstract

This paper proposes a method based on the use of the undecimated wavelet packet transform (UWPT) for estimation of the reference compensating current in shunt active power filters. The UWPT is used as a filter bank for extraction of the harmonic components drawn by a nonlinear load and estimation of the reference current for compensation of the harmonic distortion. The method proposed can be implemented on-line using half-cycle sampling window width and decomposes the input signal in uniform frequency bands with the fundamental and the odd harmonic frequencies in the center of each band, enabling the global or partial compensation harmonic and interharmonic distortion. The method proposed shows good performance in stationary and transient conditions.