MITIGATION OF SUPRAHARMONICS IN MICROGRIDS USING PARABOLIC CARRIER-BASED PWM-CONTROLLED SHUNT ACTIVE FILTERS

Microgrids (MGs) are having more difficulty sustaining power quality (PQ) as renewable energy sources (RES) become more widely integrated. The issue of supraharmonics (SH), characterized by high-frequency emissions spanning from 2 kHz to 150 kHz, holds significant importance. The switching processes used in these RES power electronic converters are to blame for these harmonics. Traditional passive filters and capacitor banks are ill-equipped to deal with the dynamic changes in system characteristics that occur at the PCC. Voltage swell, unbalance, and power factor problems result from this. The Shunt Active Filter (SAF) has shown superior efficacy in mitigating harmonic issues in power systems. Nonetheless, its performance is contingent upon the rapidity and precision of its control algorithms. This paper employs the parabolic carrier-based pulse-width modulation (PWM) technique to regulate current in SAF, thereby minimizing SH. This method incorporates using a pair of positive and negative parabolic PWM carriers to control the switching states of the two switches in the converter phase leg, simultaneously constraining the current tracking error within the nonlinear parabolic region. The proposed filter is designed using the MATLAB/Simulink environment and used in a modelled MG with specified ratings. The results of the harmonic analysis showed a distortion contribution in the SH range of merely 0.03%. The minimal increase in THD when extending the analysis up to 150 kHz demonstrates the active filter’s effectiveness in suppressing SH.