Reference current computation for three-level shunt active filter under distorted and unbalanced conditions

This paper analyzes the feasibility and convenience of applying the modified version of the instantaneous reactive power theory instead of the traditional instantaneous reactive power theory for the computation of reference currents in three-level NPC shunt active power filter (SAPF). The proposed method is based on the use of high selectivity filter (HSF) for the reference current generation, without using phase locked loop (PLL). The performance of the proposed SAPF system is validated by simulation under distorted and unbalanced conditions. Simulation results show that the proposed system can effectively compensate current harmonics and reactive power.