A MRAS-Based Algorithm with Air-Gap Active Power Calculations for Speed Estimation of DFIGs

In this paper a new speed estimation strategy is presented for rotor speed estimation of Doubly-fed Induction Generations (DFIG). The proposed algorithm is formulated extensively and a complete analysis is given to prove its stable operation. The suggested method is based on Model References Adaptive System (MRAS) and consists of a model for the evaluations of the active power transferred across the air gap. This method has implemented in stator reference frame and without using of differentiator block. The main characteristic of the proposed observer is its adaptation mechanism where a hysteresis block is used as adaptation mechanism and the stability analysis is performed based on sliding mode conditions. The effectiveness of method has been tested using MATLAB/Simulink. Simulation results show acceptable operation with negligible error and speed tracking of the observer considering obtained stability conditions.