A DSP Based Optimal Algorithm for Shunt Active Filter Under Nonsinusoidal Supply and Unbalanced Load Conditions

Dept. of Electr. Eng., Indian Inst. of Technol., Mumbai
IEEE Transactions on Power Electronics (Impact Factor: 6.01). 04/2007; 22(2):593 - 601. DOI: 10.1109/TPEL.2006.890001
Source: IEEE Xplore


The use of power electronic circuits in a wide range of applications has resulted in distorted current waveforms in the power system. This results in nonsinusoidal voltage drops across the transformers and transmission line impedances, resulting in a nonsinusoidal voltage supply at the point of common coupling. Asymmetrical distribution of large, 1-phi loads further complicates the issue by causing imbalance in the line currents of the 3-phi system. Not only should this imbalance be compensated, other parameters, such as the current total harmonic distortion and the power factor should also be maintained as per the norms. However, the requirements of harmonic free current waveforms and good power factor, under nonsinusoidal voltage conditions, are contradictory to each other. Under these conditions, an optimum performance is the best one can achieve. This paper proposes a new scheme for balancing the currents and obtaining the best compromise between the power factor and current distortion under nonsinusoidal voltage conditions. The technique does not use p-q theory and does not require sequence transformation for power calculations, even though the current is unbalanced. All the details of this work are presented

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    • "To tackle this problem, different mitigation strategies have been proposed in the literature. Such solution approaches include selective harmonics elimination control technique based on pole-zero cancelation in load transform function [5], feedback linearization theory and pole placement strategy for harmonic compensation [6], and optimal control technique in abc frame for harmonics elimination and power quality improvement during connection of nonlinear and unbalanced loads to the grid [7] were found to decrease the negative impacts of these frequencies on the utility grid. "
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    Energy 04/2015; 84. DOI:10.1016/ · 4.84 Impact Factor
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    • "The fuzzy logic and adaptive fuzzy logic controllers may be used for improving the dynamics of traditional PI controller to have improved regulation on the DC bus voltage of DSTATCOM, eliminating higher overshoot and undershoot [31] [32] [33] [34] [35]. Several publications are reported and compared the performances of different reference current generation strategies under balanced, sinusoidal, unbalanced or distorted alternating current (AC) voltages conditions [36] [37] [38]. In all of them, authors have demonstrated that under balanced and sinusoidal AC voltages conditions, the strategies such as the so-called p–q theory and synchronous reference frame theory (SRF) provide similar performances. "
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    • "Conventionally, series active power filter can be a solution for compensating unbalances by adding negative sequence voltage in series with the distribution line [3]–[5]. In some works, shunt active filters are used to inject negative sequence current to balance the current in the distribution lines and, consequently, compensate unbalances [6]–[8]. However, all these methods require additional compensation equipment which may increase the total investment cost. "
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