A novel harmonics detection method based on wavelet algorithm for active power filter

This paper proposes a novel wavelet approach for determining reference compensation currents of shunt active power filters to maintain sinusoidal source currents supplied to nonlinear loads. The theoretical and simulative results have verified that the novel approach based on the wavelet algorithm can abstract fundamental components currents effective with short transient time, less than 1/4 cycle, even when source voltages are asymmetrical distorted. The p-q algorithm based on instantaneous reactive power theory is presented to compare with the novel wavelet transform (WT) method. Simulation results show that the two approaches are both effective on compensating harmonic components of load currents under ideal source voltages, though slow delay time of the p-q method. However, when the source voltages are asymmetrical distorted, WT approach presents good performance results on maintaining sinusoidal source current while p-q algorithm could not achieve.