Current Limitation based on fast voltage control for fully grid-forming Direct Voltage Control

The application of grid forming control has challenges because of voltage source behavior with retarded adjustment to changing terminal voltage which cannot stiffly control the grid side current. Thus, a corresponding current limiting mechanism is required. The Direct Voltage Control is a partial grid-forming inverter control that operates in d/q-coordination and offers an easy solution for the current limitation’s issue by calculating difference voltages derived from Kirchhoff equations corresponding to high fast voltage controller parameter. This paper discusses the extension of the direct voltage control scheme to a fully grid-forming operation based on power balance synchronization by a swing equation instead of voltage-based synchronization with a phase-locked loop, and explains the implementation of the current limitation. The performance of the proposed control and its current limitation with different grid faults has been tested on the PST-16 Machine test system, which is simulated in EMT model with average model for simplification.