Mitigation of Harmonics in Distribution System using Shunt Active Power Filter by Fuzzy Logic Controller

Three-phase, four-wire systems are prone to various power quality (PQ) problems such as load unbalancing, low power factor, harmonics and problem of neutral current. A distribution system using Shunt Active Power Filter with thyristor controlled rectifier using Fuzzy Logic is proposed to mitigate various PQ problems in four-wire distribution systems. The mitigation of power quality issues is quite complex, so it is modified to obtain various control technique. Fuzzy logic provides a simple way to arrive at a definite conclusion based upon vague, ambiguous and missing input information. The proposed algorithm is developed using MATLAB/Simulink environment and tested for mitigation of various PQ problems. Thereafter, a hardware prototype for shunt active power filter (SAPF) is developed along with various sensors, control circuits using space digital signal processor. Gating circuits provide proper gating pulses to control SAPF as per the algorithm. Results with linear and non-linear loads have been tested under a variety of loading conditions and thoroughly analysed for its performance.