A Robust Phase-Locked Loop Algorithm to Synchronize Static-Power Converters With Polluted AC Systems

• Published in: IEEE transactions on industrial electronics (1982) Vol. 55; no. 5; pp. 2185 - 2192
• Main Authors: Perez, M.A., Espinoza, J.R., Moran, L.A., Torres, M.A., Araya, E.A.
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.05.2008; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Algorithms; Control systems; Converters; Digital control; Discrete-time systems; Erbium; Feedback loop; Filters; Networks; Noise; Oscillators; Phase locked loops; Pollution; pulsewidth-modulated power converters; Rejection; Robustness; Sampling; Sampling methods; Signal generators; Phase locked loops; Discrete time systems; Pulse width modulated power converters
• ISSN: 0278-0046; 1557-9948
• DOI: 10.1109/TIE.2008.918638

In this paper, a phase-locked loop algorithm appropriated for digital-signal-processor-based control implementations, where the operation of a static-power converter needs to be synchronized with an ac network, is presented. The proposed algorithm includes a multiplier, a filter, a feedback closed loop, and a numerically controlled oscillator stage. As a result, a discrete sine (and cosine) signal is generated in synchronism with the fundamental component of an external-reference (ER) signal. Moreover, the sampling period of the algorithm is adjusted at each sampling instant such that an integer number of sampling periods per period of the ER signal is ensured. This is the main feature, and it is achieved by using a discrete rectangular window filter and a discrete controller. The proposed algorithm code is simple, stable, and presents high noise rejection. A comprehensive theoretical justification and various rigorous experimental tests are included.