Abstract
A second-order generalized integrator (SOGI) is a resonant regulator with a pair of complex-conjugate poles, and therefore, with infinite magnitude at its center frequency. Thanks to this property, one can put together a set of m SOGIs in an elegant way and decompose a single-phase signal into its constituent frequency components and detect their amplitude and phase angle. Such a configuration, which is often referred to as the multi-SOGI (MSOGI) structure, requires a frequency estimator to adapt the center frequency of SOGIs to frequency changes. This frequency estimation is often provided by interconnecting the MSOGI structure with a basic frequency-locked loop (FLL) or phase-locked loop (PLL). The resulting structures are known as the MSOGI-FLL and MSOGI-PLL. These structures and their close variants are mathematically difficult to analyze probably because of the lack of a linear model for these systems. This article aims to bridge this research gap. First, it is shown how linear time-periodic (LTP) models of the MSOGI-FLL and MSOGI-PLL can be obtained. The model verification, obtaining open-loop harmonic transfer function from the LTP model, and LTP stability assessment of MSOGI-based synchronization systems are the next parts of this article. Finally, some close variants of the MSOGI-FLL/PLL are considered and their modeling and stability assessment are briefly discussed.
Original language | English |
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Journal | IEEE Transactions on Power Electronics |
Volume | 37 |
Issue number | 5 |
Pages (from-to) | 5062-5077 |
Number of pages | 16 |
ISSN | 0885-8993 |
DOIs | |
Publication status | Published - 1 May 2022 |
Bibliographical note
Publisher Copyright:IEEE
Keywords
- Frequency estimation
- Frequency locked loops
- Frequency-locked loop (FLL)
- Harmonic analysis
- linear time-periodic (LTP)
- Mathematical models
- modeling
- Phase locked loops
- phase-locked loop (PLL)
- Power system stability
- Signal processing algorithms
- single-phase systems
- synchronization