Enhanced Current-limiting Method for Grid-forming Converters based on Virtual Admittance Matrix

To achieve reliable integration of grid-forming (GFM) converters into the grid, it is crucial to address their lack of overcurrent capability compared to synchronous generators. However, existing current limiting methods struggle to suppress transient overcurrent immediately after a grid disturbance while maintaining the voltage source operation of the GFM converter. This paper proposes an enhanced current limiting strategy that calculates the current reference using a virtual admittance matrix. The matrix-based approach can suppress the natural response of the inductor to consistently provide a steady-state current reference value. As a result, the GFM converter can effectively limit overcurrent during both transient and steady-state time scales while maintaining its natural grid service provision ability. The validity of the proposed method is demonstrated through experimental results.