Small-signal modelling and stability assessment of phase-locked loops in weak grids
Author
dc.contributor.author
Burgos Mellado, Claudio Danilo
Author
dc.contributor.author
Costabeber, Alessandro
Author
dc.contributor.author
Sumner, Mark
Author
dc.contributor.author
Cárdenas-Dobson, Roberto
Author
dc.contributor.author
Sáez, Doris
Admission date
dc.date.accessioned
2019-10-30T15:40:14Z
Available date
dc.date.available
2019-10-30T15:40:14Z
Publication date
dc.date.issued
2019
Cita de ítem
dc.identifier.citation
Energies, Volumen 12, Issue 7, 2019,
Identifier
dc.identifier.issn
19961073
Identifier
dc.identifier.other
10.3390/en12071227
Identifier
dc.identifier.uri
https://repositorio.uchile.cl/handle/2250/172565
Abstract
dc.description.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.