Comparison of Voltage Harmonic Identification Algorithms for Three-Phase Systems

The rapid increase in current harmonics in the AC systems due to large introduction of solid state power switching devices is deteriorating the power quality. Consequently the interest in active filters is growing. However for their correct operation it is imperative to know the harmonic parameters such as magnitude and phase. Hence many algorithms have been developed to detect the harmonics. The frequency-domain-based algorithms (generally adopting the Fourier Transform) request high computation resources. The time-domain techniques work on the instantaneous values of signals, therefore they request fewer calculations. By these reasons, the time-domain algorithms are frequently used in active filter control. In this work, a review of principal time-domain methods is carried out. Also, their principal problems are indicated and the possible solutions and improvements are proposed. The analysis is validated by experimental results obtained with digital signal processor TMS320C6713