Robust sensorless decoupled P-Q control of doubly fed induction generators for wind power applications

Doubly fed induction generator (DFIG) is the most dominant technology used in wind energy conversion systems. Field-oriented vector control of DFIGs requires the knowledge of the instantaneous rotor position, which is usually obtained via high-resolution position sensors. However, using mechanical sensors increases the system cost and reduces the overall system reliability. This paper proposes a robust position sensorless P-Q controller for DFIG-based wind turbine, adopted based on the vector transformation of the rotor current in different reference frames. The main advantages of the proposed sensorless method are its simple control structure, accurate operation close to the synchronous speed, insensitivity to the machine parameter variations, and robustness to the grid voltage and frequency disturbances. Time-domain simulation studies are carried out in Matlab/Simulink to examine the performance of the proposed sensorless vector control scheme under various operating conditions.