부산대학교 도서관

This paper presents a new control technique for reference current generation for shunt active power filter to eliminate harmonics and to compensate the reactive power required by non-linear load using adaptive hysteresis band control. Twophase lock loop (PLL) controllers are utilised here to extract the phase angles of distorted load side current and source voltage. The normalisation and delaysignal cancellation techniques are utilized to extract the positive sequence of distorted signals, which is necessary to get the accurate information of phase angle. The peak current magnitude and the phase angle information of signals are used to generate the appropriate signals for the reference current. The adaptive hysteresis band controller, proposed in the literature is adopted here to generate the constant frequency switching pulses for the firing of 6-active switches of the inverter. The capacitor voltage is maintained constant through a voltage feedback utilising PI controller. The performance of the new active power filter (APF) is evaluated in MATLAB/Simulink power system toolbox. Simulation study provides quite satisfactory results for the elimination of harmonics and compensation of reactive power of the utility grid current under different load conditions. The total harmonic distortion (THD) is found effective to meet IEEE 519 standard recommendation on the harmonic level.