Rethinking Current Controller Design for PLL-Synchronized VSCs in Weak Grids
2022 (English)In: IEEE transactions on power electronics, ISSN 0885-8993, E-ISSN 1941-0107, Vol. 37, no 2, p. 1369-1381Article in journal (Refereed) Published
Abstract [en]
This article revisits the design of the current controller for grid-connected voltage-source converters (VSCs), considering the dynamic impacts of the phase-locked loop (PLL), weak grids, and of voltage feedforward (VFF) control. First, a single-input single-output transfer-function-based model is proposed to characterize the interactions of control loops. It is analytically found that the proportional gain of the current controller essentially aggravates the instability effect of PLL in weak grids, while the cutoff frequency of the low-pass filter used with the VFF loop has a nonmonotonic relationship with the PLL-induced instability. Then, based on these findings, a guideline for redesigning the current controller of PLL-synchronized VSCs is developed, which enables a codesign of the current controller and VFF controller. Finally, simulation and experimental results confirm the validity of theoretical analyses.
Place, publisher, year, edition, pages
Institute of Electrical and Electronics Engineers (IEEE) , 2022. Vol. 37, no 2, p. 1369-1381
Keywords [en]
Phase locked loops, Power conversion, Converters, Synchronization, Impedance, Voltage control, Power system stability, Current controller, phase-locked loop, voltage feedforward control, voltage-source converters, weak grids
National Category
Other Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
URN: urn:nbn:se:kth:diva-304210DOI: 10.1109/TPEL.2021.3105549ISI: 000707555600022Scopus ID: 2-s2.0-85113265596OAI: oai:DiVA.org:kth-304210DiVA, id: diva2:1609042
Note
QC 20211105
2021-11-052021-11-052022-06-25Bibliographically approved