Junru Chen, Federico Prystupczuk, Terence O'Donnell. Use of voltage limits for current limitations in grid-forming converters[J]. CSEE Journal of Power and Energy Systems, 2020, 6(2): 259-269.
DOI:
Junru Chen, Federico Prystupczuk, Terence O'Donnell. Use of voltage limits for current limitations in grid-forming converters[J]. CSEE Journal of Power and Energy Systems, 2020, 6(2): 259-269. DOI: 10.17775/CSEEJPES.2019.02660.
Use of voltage limits for current limitations in grid-forming converters
Renewable generation interfaced through grid-forming converters are proposed as a replacement for synchronous generators in power systems. However
compared to the synchronous generator
the power electronics converter has a strict limit on the current to avoid overcurrent damage. The grid-forming converter acts like a voltage source
directily controlling the voltage. This conflicts with the operation of the conventional current limit control
which is applied to a current source. The switch between the voltage control and current control aimed to impose the current limit leads to synchronization instability. This paper proposes a novel control scheme which can be applied to the grid forming voltage control in order to enforce current limits. The proposed method has been verified through simulation and hardware tests in both symmetrical and asymmetrical faults to perform current suppression while maintaining synchronization stability in the voltage control mode.