Constant power control of wind turbines during unbalanced faults

This paper includes a control strategy for the fault-ride-through performance of wind turbines connected to the grid by means of fully rated converter. The proposed control strategy does not require the use of PLLs or FLLs for grid connection. The effects of the proposed control strategy on the low speed shaft and the gearbox has been studied on the NREL 5 MW reference wind turbine, modeled with the NREL FAST code. The generator, power electronics and electric grid, together with their controls have been simulated in PSCAD. The proposed controller has shown good fault ride-through performance to unbalanced faults with reduced impact on the wind turbine gearbox and low speed shaft.