A Simple Yet Parameter-Less and Cost-Effective Rotor Speed-Cum-Position Estimator for Encoder-Free Control of Doubly-Fed Induction Generator

A hybrid process for estimating rotor speed and position is proposed for the doubly-fed induction generator (DFIG) in connection with its stator flux-oriented vector control. The improved characteristics of the proposed method are: 1) unlike existing schemes, this method does not exhibit error due to discrepancy in the machine's parameters and 2) the number of sensors is reduced in comparison with the other estimators. As a result, the estimation model achieves parameter independence while also using fewer sensors, i.e., a cost-effective, reliable, and compact scheme is suggested due to the reduction of physical element and parameter dependency. In the proposed case, it is not necessary to calculate fluxes or intermediate variables, as well as to use fewer measured input quantities, which reduces the calculation burden. Differentiation and integration of variables are absent. This prevents the magnification of noise and low-frequency signals on the primary signal. The operations of the proposed estimator under diverse conditions are tested using a real-time working prototype. The performances here support the theoretical conclusions. The comparisons with other state-of-the-art techniques indicate the superiority of the proposed estimation scheme.

Automated summary

This paper proposes a hybrid process for estimating rotor speed and position for the doubly-fed induction generator (DFIG). The method has improved characteristics including parameter independence and reduced number of sensors compared to existing schemes. The proposed estimator achieves cost-effectiveness, reliability, and compactness by reducing physical elements and parameter dependency. Experimental results demonstrate the superiority of the proposed estimation scheme compared to other state-of-the-art techniques.