Real-Time Implementation of PV fed Universal Active Power Filter Using CF-SOGI based IPBT Control Scheme

Abstract

This paper proposed a new control scheme of comb filter based second-order generalized integrator (CF-SOGI) in instantaneous power balance theory (IPBT) for photovoltaic (PV) fed universal active power filter (UAPF). The conventional SOGI frequency locked loop (SOGI-FLL) can provide good accuracy and fast dynamics, and better filtering abilities during idle grid conditions. To enhance the filtering ability and improve the accuracy under distorted conditions usually multiple notch filters are used. However, it suffers from a heavy computational burden due to the presence of multiple filters, the system becomes a complex structure and deteriorate dynamic performance. To overcome the above a comb filter is incorporated in the conventional SOGI-FLL. It extracts the frequency and fundamental positive component of voltage under adverse grid voltages. Along with it, a new IPBT control scheme generates the reference signals for UAPF using reference and load power calculations. It improves the dynamic performance by maintaining power balance in the system along with effective DC voltage regulation. The proposed system enhances the power quality issues on both source and load side as per IEEE-519 and integrates the PV into the utility grid on a two-stage topology. Also, it extracts the maximum power from the PV and delivers it to the load and grid connected at the point of interconnection (PIC). The system with the proposed control scheme is simulated on MATLAB/Simulink and the same is validated in the laboratory prototype experimental setup. The performance of a system is validated under grid voltage fluctuations, non-linear load, unbalance load, and change in irradiation conditions.