Feasible Region of Droop Gain of Power Synchronization Loop Based Wind Generator Under Rotor Speed Limitation

This paper provides a design method for the droop coefficient of grid-forming wind turbine (WT) under power synchronization loop (PSL) control. First, based on the dynamic model of PSL controlled WT, the relationship between rotor speed deviation and the droop coefficient is derived. The analysis shows that the larger droop coefficient, the large rotor speed deviations are, indicating that there must be an upper limit for the droop coefficient. Subsequently, one upper bound of coefficient is derived by ensuring the existence of equilibrium. Finally, by considering the transient rotor speed constraints, the maximum droop coefficient is scaled to obtain a conservative value that ensures the WT does not reach the lower rotor speed limit during the frequency disturbance.