Decoupled Double Synchronous Reference Frame PLL for Power Converters Control

• Published in: IEEE transactions on power electronics 2007-03, Vol.22 (2), p.584-592
• Main Authors: Rodriguez, P., Pou, J., Bergas, J., Candela, J.I., Burgos, R.P., Boroyevich, D.
• Format: Article
• Language: English
• Subjects: Applied sciences; Circuit properties; Circuits of signal characteristics conditioning (including delay circuits); Decoupling; Detectors; Distortion; Distributed control; Electric currents; Electric potential; Electric power; Electric, optical and optoelectronic circuits; Electrical engineering. Electrical power engineering; Electrical machines; Electronic circuits; Electronics; Exact sciences and technology; Flexible AC transmission systems; Frequency estimation; Frequency synchronization; Grid-connected converters; Phase detection; phase locked loop (PLL); Phase locked loops; positive sequence signals detection; Power converters; Power electronics, power supplies; Regulation and control; Robustness; Signal convertors; Synchronous; synchronous reference frame (SRF); Uninterruptible power systems; Utilities; Voltage; Voltage control
• ISSN: 0885-8993; 1941-0107
• DOI: 10.1109/TPEL.2006.890000

This paper deals with a crucial aspect in the control of grid-connected power converters, i.e., the detection of the fundamental-frequency positive-sequence component of the utility voltage under unbalanced and distorted conditions. Specifically, it proposes a positive-sequence detector based on a new decoupled double synchronous reference frame phase-locked loop (DDSRF-PLL), which completely eliminates the detection errors of conventional synchronous reference frame PLL's (SRF-PLL). This is achieved by transforming both positive- and negative-sequence components of the utility voltage into the double SRF, from which a decoupling network is developed in order to cleanly extract and separate the positive- and negative-sequence components. The resultant DDSRF-PLL conducts then to a fast, precise, and robust positive-sequence voltage detection even under unbalanced and distorted grid conditions. The paper presents a detailed description and derivation of the proposed detection method, together with an extensive evaluation using simulation and experimental results from a digital signal processor-based laboratory prototype in order to verify and validate the excellent performance achieved by the DDSRF-PLL