A Nonadaptive Window-Based PLL for Single-Phase Applications

• Published in: IEEE transactions on power electronics Vol. 33; no. 1; pp. 24 - 31
• Main Authors: Golestan, Saeed, Guerrero, Josep M., Vasquez, Juan C.
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.01.2018; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Compensators; Complexity; Detectors; Dynamic response; Estimation; Frequency estimation; Grid-connected applications; Harmonic analysis; moving average filter (MAF); Oscillators; Phase locked loops; Phase locked systems; phase-locked loop (PLL); Signal generators; single-phase systems; synchronization; Transfer functions
• ISSN: 0885-8993; 1941-0107
• DOI: 10.1109/TPEL.2017.2713379

The rectangular window filter, typically known as the moving average filter (MAF), is a quasi-ideal low-pass filter that has found wide application in designing advanced single-phase phase-locked loops (PLLs). Most often, the MAF is employed as an in-loop filter within the control loop of the single-phase PLL. The in-loop MAF, however, causes a large phase delay and, hence, makes the PLL dynamic response slow. Recently, using MAFs as a prefilter/quadrature signal generator (QSG) before the PLL input has been suggested. As the MAFs are outside the PLL control loop, the problem of slow dynamic response is avoided. Nevertheless, the PLL implementation complexity considerably increases as MAFs are frequency-adaptive and, therefore, they require an additional frequency detector for estimating the grid frequency. To reduce the implementation complexity while maintaining a good performance, using a nonadaptive MAF-based QSG with some error compensators is suggested in this letter. The effectiveness of the resultant PLL, which is briefly called the nonadaptive MAF-based PLL, is verified using experimental results.