A novel position sensor-less control scheme of Doubly Fed Induction Wind Generator based on MRAS method

This paper presents a novel position sensor-less method based on model reference adaptive system (MRAS) for the control of variable speed constant frequency (VSCF) doubly fed induction generator (DFIG). In this method the components of the stator flux in stationary reference coordinates are used for both reference and adjustable models. The reference model is given by stator equations with flux as the outputs while the rotor equations are used for adjustable model to calculate the stator flux by using rotor quantities such as rotor currents, position and flux. In order to get the accurate rotor flux of the adjustable model, a modified integrator has been used. No stator current sensors are used in the proposed position and speed estimation method, therefore it can reduce the costs and improve the control system reliability compared with other position sensor-less methods. The proposed control method has been experimentally verified on a 7.5 kW DFIG system using back-to-back converter. The experimental results show that good performance has been obtained with proposed position sensor-less control method.