Application of fast lifting wavelet transform to the estimation of harmonic for shunt active power filters

This paper presents a new harmonic measurement scheme based on lifting wavelet transform (LWT) for shunt active power filters (APFs). As one of methods to build second-generation wavelets, LWT can be easy to achieve in time domain for its original bit location calculation. And it could lessen calculation complexity and depress course due to its particular structure, compared with first generation wavelet algorithm (WT). The theoretical and simulative results have verified that the novel LWT approach can abstract harmonic components currents effective with short transient time even when source voltages are asymmetrical distorted. It can accurately detect harmonic components more quickly than classical WT algorithm.