Sensorless MRAS control of brushless doubly-fed reluctance generators for wind turbines

A new model reference adaptive system based estimation technique for vector control of a brushlesss doubly fed reluctance generator without a shaft position sensor is proposed. The rotor speed is being precisely observed in a closed-loop fashion through an iterative error elimination process between the measured and estimated secondary current angles in a stationary frame. Contrary to the existing adaptive observer designs reported in the open literature for this emerging generator technology, the reference model only uses the secondary current measurements and does not need any machine parameters for calculations. Furthermore, the stationary frame current components estimates are obtained using the measured grid voltages and currents, which has provided prospects for much higher accuracy and superior overall performance. The realistic simulations and the accompanying parameter sensitivity studies have shown the great controller potential for typical operating conditions of wind turbines as the main target application.