An Improved Second-Order Generalized Integrator Based Quadrature Signal Generator

• Published in: IEEE transactions on power electronics 2016-12, Vol.31 (12), p.8068-8073
• Main Authors: Zhen Xin, Xiongfei Wang, Zian Qin, Minghui Lu, Poh Chiang Loh, Blaabjerg, Frede
• Format: Article
• Language: English
• Subjects: Attenuation; Damping; DC offset; Electric currents; Filtering; first-order system; Frequencies; Generators; Harmonic analysis; harmonic attenuation; Power harmonic filters; Power supply; quadrature signal generator; second-order generalized integrator; second-order system; Transfer functions
• ISSN: 0885-8993; 1941-0107
• DOI: 10.1109/TPEL.2016.2576644

The second-order generalized integrator based quadrature signal generator (SOGI-QSG) is able to produce in-quadrature signals for many applications, such as frequency estimation, grid synchronization, and harmonic extraction. However, the SOGI-QSG is sensitive to input dc and harmonic components with unknown frequencies (e.g., interharmonics). To overcome the drawback, this letter begins by analyzing the dynamic response of SOGI-QSG from the first-order system (FOS) perspective. A second-order SOGI-QSG (SO-SOGI-QSG) with a fourth-order transfer function is then proposed, after referring to the relationship between standard FOS and second-order system. The proposed method is subsequently found to inherit the simplicity of the SOGI-QSG, while demonstrates better disturbance attenuation. Its parameter design procedure is also easy to understand, and can be followed step-by-step without difficulty. Performance of the proposed SO-SOGI-QSG is finally validated by experimental results presented in this letter.