Improved phase-locked loop for robust and fast tracking of three phases under unbalanced electric grid conditions ABSTRACT:Modern electric power transmission and distribution systems need accurate phase information on three-phase grid voltages and/or currents. Conventional three-phase synchronous reference frame-based phase-locked loop (SRF-PLL) is generally sufficient for phase tracking during balanced operating conditions. However, SRF-PLL becomes inadequate when unbalance exists in the three-phase input signal. Because, unbalance in input signal set causes a double-frequency ripple and as a result, an ideal output signal cannot be obtained. Previous studies have focused on improving the SRF-PLL performance by removing this ripple with using delayed signals methods such as delayed signal cancellation (DSC)-PLL methods. Although these methods give ideal output signals, a certain time delay is occurred. In this study, an effective method DIF-PLL based on adding another signal, which has reverse polarity ripple is proposed for obtaining ideal output signal and fast tracking of phase angle. Performance of the DIF-PLL is compared with the performances of SRF-PLL and DSC-PLL methods. The performances of these methods are also examined for the presence of the harmonics. The results show that the proposed method has a better three-phase tracking performance than the others under balanced and unbalanced electric grid conditions. Did you like this research project? To get this research project Guidelines, Training and Code... Click Here facebook twitter google+ linkedin stumble pinterest Forecasting dissolved gases content in power transformer oil based on weakening buffer operator and least square support vector machine–Markov New network sensitivity-based approach for real-time complex power flow calculation