Design Considerations of Current-Limiting Control for Grid-Forming Capability Enhancement of VSCs under Large Grid Disturbances

There is an increasing demand on the grid-forming (GFM) capability of grid-connected voltage-source converters under large grid disturbances, even when the current-limiting control (CLC) is triggered. This letter demonstrates that the GFM capability can be maximized by matching the angle of virtual impedance emulated by the CLC and that of the passive impedance composed by filter impedance and grid impedance. This finding offers insight for optimizing the CLC with the enhanced GFM capability. The experimental results are given to verify the theoretical findings.