Droop Coefficient Design of Wind Turbine Considering Rotor Speed Constraints

This letter provides the design rule of the droop coefficient for the power synchronization loop (PSL) based grid-forming wind turbine (WT) considering the transient rotor speed constraints. The dynamic model for PSL-based WT is established first, and it is shown that the larger the droop coefficient, the larger the steady-state rotor speed deviation is. Accordingly, the maximum droop coefficient for ensuring the existence of equilibrium is derived. Finally, with the proper scaling of the transient rotor dynamic equation, the conservative evaluation of the maximum droop coefficient is obtained to make sure the WT does not touch the lower limit of the rotor speed during disturbance.