Journal of Northeastern University Natural Science ›› 2020, Vol. 41 ›› Issue (4): 457-463.DOI: 10.12068/j.issn.1005-3026.2020.04.001

• Information & Control •     Next Articles

Grid Signal Synchronization Method by Using Cascaded Filter Phase-Locked Loop

WANG An-na, TANG Ai-bo, LIU Yu-ning, SONG Chong-hui   

  1. School of Information Science & Engineering, Northeastern University, Shenyang 110819, China.
  • Received:2019-06-11 Revised:2019-06-11 Online:2020-04-15 Published:2020-04-17
  • Contact: TANG Ai-bo
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Abstract: In the case of grid fault conditions, the traditional SRF-PLL has large frequency and phase signal detection errors when performing grid signal synchronization, and a grid signal synchronization method based on cascaded filter phase-locked loop was proposed. In QT1-PLL, the cascaded filtering structure was used to improve the filtering performance and the response speed of the system. The effect of grid frequency offset on phase-locked results can be eliminated by adding phase and amplitude compensation links in the phase-locked loop. Simulation and experimental results showed that accurate frequency and phase detection can be achieved in 1.5 grid periods when the voltage signal has a 20° phase step and 4 Hz frequency step. When the frequency and phase overshoot are 0.5 Hz and 4°, respectively, it can meet the fast and accurate requirements of the grid-connected system, and verify the correctness and effectiveness of the proposed theory.

Key words: cascaded filter, phase-locked loop, signal synchronization, frequency offset, phase step

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