Small-Signal Modelling and Stability Assessment of Phase-Locked Loops in Weak Grids

Claudio Burgos-Mellado, Alessandro Costabeber, Mark Sumner, Roberto Cárdenas-Dobson and Doris Sáez
Additional contact information
Claudio Burgos-Mellado: Department of Electrical Engineering, Faculty of Mathematical and Physical Sciences, University of Chile (DIE), Av. Tupper 2007, Santiago 8370451, Chile
Alessandro Costabeber: PEMC Group, University of Nottingham, Nottingham NG7 2RD, UK
Mark Sumner: PEMC Group, University of Nottingham, Nottingham NG7 2RD, UK
Roberto Cárdenas-Dobson: Department of Electrical Engineering, Faculty of Mathematical and Physical Sciences, University of Chile (DIE), Av. Tupper 2007, Santiago 8370451, Chile
Doris Sáez: Department of Electrical Engineering, Faculty of Mathematical and Physical Sciences, University of Chile (DIE), Av. Tupper 2007, Santiago 8370451, Chile

Energies, 2019, vol. 12, issue 7, 1-30

Abstract: This paper proposes a low-complexity small signal model for a 3-leg converter connected to a balanced three-phase, three-wire weak grid and synchronised to this grid using a PLL implemented in a synchronous rotating d-q axis. A thorough analysis of the system stability as a function of the PLL bandwidth and the short circuit ratio (SCR) of the grid is performed based on a linearised model. By using the proposed model, an improved design process is proposed for the commonly used dq -PLL that accounts for the potential stability issues which may occur in weak grids. Using the proposed approach, it is possible to optimise the PLL design to find the fastest PLL that can operate stably considering the SCR of the grid. In addition, the proposed model is very simple, resulting in a straightforward design tool that could also be used for online stability monitoring. The method is validated through simulations and experimental results from a 5kW laboratory system.

Keywords: phase-locked loop (PLL) stability; small signal analysis; grid-connected converter; weak grid; PLL bandwidth analysis; short circuit ratio (SCR) (search for similar items in EconPapers)
JEL-codes: Q Q0 Q4 Q40 Q41 Q42 Q43 Q47 Q48 Q49 (search for similar items in EconPapers)
Date: 2019
References: View references in EconPapers View complete reference list from CitEc
Citations:

Downloads: (external link)
https://www.mdpi.com/1996-1073/12/7/1227/pdf (application/pdf)
https://www.mdpi.com/1996-1073/12/7/1227/ (text/html)

Related works:
This item may be available elsewhere in EconPapers: Search for items with the same title.

Export reference: BibTeX RIS (EndNote, ProCite, RefMan) HTML/Text

Persistent link: https://EconPapers.repec.org/RePEc:gam:jeners:v:12:y:2019:i:7:p:1227-:d:218468

Access Statistics for this article

Energies is currently edited by Ms. Agatha Cao

More articles in Energies from MDPI
Bibliographic data for series maintained by MDPI Indexing Manager ().