A new topology and control strategy for extraction of reference current using single phase SOGI-PLL for three-phase four-wire Shunt Active Power Filter

This paper describes an advanced controller to enhance the performance of SHAPF (Shunt Active Power Filter) to improve power quality based on single-phase SOGI-PLL for a three - phase four-wire system. The SHAPF performs various functions such as harmonics elimination, reactive power and neutral current compensation and load balancing under distorted load conditions with self supporting DC bus voltage. This control algorithm is used to extract the fundamental values of active and reactive components of load currents for estimating of reference currents based on three single-phase SOGI-PLLs. The main reason to adopt SOGI-PLL is its capability of current tracking for compensation. The control algorithm is tested and performed using MATLAB/Simulink with load unbalancing and its performance is found satisfactory.