Reduction of Total Harmonic Distortion (THD) in Source Current Using a Shunt Active Power Filter with P-Q Theory and PI Controller

The rising prevalence of non-linear loads at the point of common coupling (PCC) is severely affecting power quality, emphasizing the urgent need for shunt active power filters (SAPFs). In order to comply with the strict regulations set by contemporary utility grids, these filters are essential for reducing harmonics and guaranteeing power systems’ dependability. The main goal of this research is to create a system that can provide a balanced, sinusoidal source current waveform that is precisely synced with the matching voltage. Achieving a unity power factor and a notable decrease in the source current’s Total Harmonic Distortion (THD) are made possible by this synchronization. A thorough and systematic approach to the design of a SAPF for mitigating current harmonics is presented in detail. The goal of the suggested approach is to lower the source current’s THD. Utilizing the instantaneous power theory ($p-q$ theory), the reference current is obtained. A proportional-integral (PI) controller controls the DC-link voltage, and hysteresis current control generates gate pulses that control the Voltage Source Inverter (VSI) switches. Comprehensive modeling and simulation of the SAPF are carried out in MATLAB/Simulink for a balanced system with non-linear loads. According to the acceptable limitations specified in IEEE Standard 519-2014, the result of simulation demonstrate that the suggested filter successfully lowers harmonic distortion.