Sensorless Field Oriented Control of DFIGs Using a Rotor-Current-Based MRAS Observer under Grid Voltage Dip

This paper proposes a new application of sensorless control method for doubly fed induction generator (DFIG) using rotor-current-based MRAS observer (RCMO) under grid voltage dip. MRAS means model reference adaptive system. In this paper the method of control of DFIG is vector control VC (or field oriented control FOC). The position and speed of rotor are estimated by RCMO instead of measuring. DFIG is connected to a grid with a balanced voltage dip on PCC and is tested by large variation in rotor speed. Simulation results using MATLAB/Simulink are presented for a 2-MW DFIG. The simulation results show the decoupled control of active and reactive power of DFIG in three conditions: a) normal voltage of grid b) grid voltage dip c) huge variation at wind speed. The results show that the estimated speed of rotor and power produced in DFIG carefully follows the references. The conclusion of simulation results is that for decoupled control of active and reactive power of DFIG, application of RCMO method is favorable and acceptable under balanced voltage dips and variable speed wind as well as conventional VC.