A 2nd Order LPF Wavelet based Control Scheme for Shunt Active Power Filter

Shunt Active Power Filters (APFs) play an important role in mitigating load current related power quality (PQ) challenges. Their dynamic performance largely depends on the control technique deployed. This paper proposes a simple and novel 2nd order low pass filter (LPF) wavelet based control scheme for Shunt APF. The control technique is driven on the concept of wavelet based multiresolution analysis (MRA) where only one level of the pyramid is deployed to extract the fundamental frequency component of an unbalance and non-linear load current. Second order generalized integrators (SOGIs) are then employed to extract the positive sequence component with less than 1 cycle delay. Matlab/Simulink simulations are carried out to validate the proposed technique under several operating conditions using the Synchronous reference frame (SRF) theory based control as benchmark.