Stator side active and reactive power control with improved rotor position and speed estimator of a grid connected DFIG (doubly-fed induction generator)

• An improved rotor position estimator has proposed for controlling DFIG (doubly-fed induction generator).
• This estimator has lesser parameter sensitivity than existing techniques.
• The estimation control loop does not require any kind of flux estimation.
• It can start on fly and also works satisfactorily near synchronous speed operation.
• Generated powers are least affected by the proposed estimator based control loop.

High performance vector control of DFIG (doubly-fed induction generator) in connection with wind power generation demands accurate rotor position and speed information to the controller. In this paper, the measured stator and rotor current and voltages are used to calculate the rotor position and speed based on MRAS (model reference adaptive system) control strategy. The air-gap EMF (electromotive force) is taken as the working variable. The main features of the proposed scheme meets various desirable requirements of a high performance controller e.g. good dynamic response, no requirement of flux estimation, no necessity of low frequency signal integration or usage of no differentiator for computation. Moreover, the performance of the control loop is least affected by the machine parameters variation. The proposed method is simple, reasonably accurate and can be easily applied for real time implementation. Different experiments and simulations are performed on a 3.2 kW slip ring induction machine and the results are compared with traditional schemes to validate the proposed concept.