Title :
A software phase locked loop for unbalanced and distorted utility conditions
Author :
Naidu, S.R. ; Mascarenhas, A.W. ; Fernandes, D.A.
Author_Institution :
Dept. of Electr. Eng., Univ. Fed. de Campina Grande, Paraiba, Brazil
Abstract :
A software phase locked loop (PLL) for custom power devices is described in this paper. The PLL uses the previous and current samples of the 3-phase utility voltages and separates them into the sequence components. The phase angle and frequency of the estimated positive sequence component are tracked by the first two stages of the PLL. The third stage estimates the parameter Δθ which is required by the first stage. Simulations of the performance of the PLL have been presented, as well as the performance of a dynamic voltage restorer incorporating the proposed PLL. The proposed PLL performs well under unbalanced and distorted utility conditions. It tracks the utility phase angle and frequency smoothly and also extracts the sequence components of the utility voltages. A DVR incorporating the PLL provides voltage support to sensitive loads and also acts as a harmonic filter.
Keywords :
phase detectors; phase locked loops; power harmonic filters; power supply quality; power system harmonics; power system simulation; PLL; dynamic voltage restorer; harmonic filter; phase detection; phase locked loops; power devices; voltage sags; Brazil Council; Control systems; Filters; Frequency estimation; Phase distortion; Phase estimation; Phase locked loops; Power quality; Power system restoration; Voltage fluctuations;
Conference_Titel :
Power System Technology, 2004. PowerCon 2004. 2004 International Conference on
Print_ISBN :
0-7803-8610-8
DOI :
10.1109/ICPST.2004.1460157