Ahead of Print article · Journal article
A Grid Synchronization PLL Method Based on Mixed Second- and Third-Order Generalized Integrator for DC-Offset Elimination and Frequency Adaptability
The second order generalized integrator (SOGI) has been widely used to implement grid synchronization for grid-connected inverters, and from grid voltages it is able to extract the fundamental components with an output of two orthogonal sinusoidal signals. However, if there is a dc offset existing in the grid voltages, the general SOGI’s performance suffers from its generated dc effect in the lagging sine signal at the output.
Therefore, in this paper, a mixed second- and third-order generalized integrator (MSTOGI) is proposed to eliminate this effect caused by the dc offset of grid voltages. A detailed theoretical analysis on the proposed MSTOGI is presented to reveal the mechanism of eliminating the dc offset. After that, the MSTOGI is applied to a phase-locked loop (PLL) and thereby establish an MSTOGI-PLL which is more adaptable to various grid conditions and power quality.
Moreover, a frequency-adaptive control scheme is added to the proposed MSTOGI-PLL to eliminate the phase difference between the PLL output and the grid in grid-connected applications where the grid frequency may vary. Finally, the experimental results from a laboratory prototype are given to demonstrate and verify the effectiveness of the proposed MSTOGI-PLL in terms of steady-state performance, dynamic response and frequency adaptability.
Language: | English |
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Publisher: | IEEE |
Year: | 2018 |
Pages: | 1-1 |
ISSN: | 21686785 and 21686777 |
Types: | Ahead of Print article and Journal article |
DOI: | 10.1109/JESTPE.2018.2810499 |
ORCIDs: | Zhang, Zhe |
Non-ideal grid Phase-locked loop (PLL) Synchronization Third-order generalized integrator (TOGI)
DC effect DC offset elimination Harmonic analysis MSTOGI-PLL Nonideal grid PLL output Phase locked loops Power harmonic filters Resonant frequency Steady-state Transfer functions adaptive control frequency adaptability frequency control frequency-adaptive control scheme grid conditions grid frequency grid synchronization PLL method grid voltages grid-connected applications grid-connected inverters invertors lagging sine signal orthogonal sinusoidal signals phase locked loops phase-locked loop phase-locked loop (PLL) power grids power system control power system harmonics second-order generalized integrator synchronisation synchronization third-order generalized integrator third-order generalized integrator (TOGI) voltage control