A wideband harmonic self-mitigation controller of the VSG-based islanded microgrid without harmonic extraction

• Published in: Electric power systems research 2024-09, Vol.234, p.110551, Article 110551
• Main Authors: Li, Gaoxiang, Song, Wenhao, Liu, Xiao
• Format: Article
• Language: English
• Subjects: Impedance model; Islanded microgrid; Load disturbance; Power quality; VSG
• ISSN: 0378-7796; 1873-2046
• DOI: 10.1016/j.epsr.2024.110551

•Wideband harmonic mitigation.•No need to extract harmonic components.•Simple controller implementation.•Can be applied to other microgrid control, such as Droop control. In virtual synchronous generator (VSG)-based islanded microgrid, voltage harmonics induced by nonlinear loads seriously degrade system power quality. Existing harmonic mitigation controllers mainly rely on the extracted harmonic components to control, and generally have the weakness that can only mitigate harmonics with known frequencies. To better improve the power quality of the islanded microgrid, a wideband harmonic self-mitigation controller (WHSMC) is proposed in this paper, which can effectively mitigate wideband voltage harmonics above the fundamental frequency without extracting harmonics. Firstly, based on the impedance method, the reason why nonlinear loads will cause voltage harmonics in the islanded microgrid is analyzed in detail. Secondly, by establishing the impedance model of VSG with the proposed WHSMC, the mechanism how the proposed WHSMC mitigates voltage harmonics without knowing the harmonic frequency in advance is theoretically revealed. Finally, the effectiveness of the proposed WHSMC is verified through simulation and experimental results. The experiments indicate that the voltage total harmonic distortion (THD) can decrease from 7.02 % to 3.41 % under nonlinear load disturbance and from 8.27 % to 3.99 % under pulse load disturbance. [Display omitted]