Droop Control Method for Grid-forming Inverters Based on Virtual Inertia of Lead-lag links

The increasing proportion of distributed generation (DG) leads to a significant decrease in the effective inertia of the power system and a weakening trend in system strength, resulting in increasingly severe stability issues. This paper presents a droop control method based on virtual inertia of lead-lag links to improve the performance of grid-forming inverters in stand-alone and grid-connected operation modes. By adding lead-lag links on the basis of traditional droop control, the zero and pole parameters of the lead-lag links are adjusted to ensure that the inverter has sufficient virtual inertia during the transient process while increasing its damping oscillation ability. It can provide virtual inertia and damping rate of change of frequency (ROCOF) in stand-alone operation mode, damp power oscillation and shorten adjustment time in grid-connected operation mode. The small signal model and simulation results validate the effectiveness of the proposed method.