Enhanced Fault Ride-Through of Grid-Forming Converter with Extra Internal Voltage Source Rotation

Recently, power systems require grid-forming (GFM) converters to provide ancillary grid services to facilitate recovery from various disturbances, which is also called GFM capability. However, the GFM capability has an inherent adverse effect from the perspective of transient stability. The proposed method in this paper overcomes this trade-off by extra rotation of the internal voltage source of GFM converters. Extra rotation is applied simultaneously with the current limitation strategy to improve transient stability while maintaining natural grid service provision ability. Furthermore, the proposed method works effectively regardless of the type of grid disturbances. The validity of the proposed method is verified with experiments by a 3 kW GFM converter system.