Interaction analysis and enhanced design of grid-forming control with hybrid synchronization and virtual admittance loops

The hybrid power- and voltage-based synchronization control method has shown potential for enhancing the stability of grid-forming (GFM) inverters. However, its effectiveness may be compromised if other control loops are not properly designed. To address the control-loop interactions, this paper presents a design-oriented analysis method for multiloop-controlled GFM inverters. The method begins by identifying the dominant oscillation modes through modal analysis. The sensitivities of damping ratios to control parameters are then determined for the dominant modes, which allows for characterization of control-loop interactions. A co-design method of GFM control is next developed based on the sensitivity analysis. Lastly, simulations and experimental results are presented to confirm the effectiveness of the method.