An MRAS Observer-Based Speed Sensorless Control Method for Dual-Cage Rotor Brushless Doubly Fed Induction Generator

In this paper a model reference adaptive system (MRAS) speed observer based on the power winding (PW) active power and reactive power for dual-cage rotor brushless doubly fed induction generator (DCR-BDFIG). The mathematical relationship between the PW current and control winding (CW) current is derived first. Then, to reduce costs and to improve the reliability, a PW power-MRAS-based speed observer is designed with the stability analyzed. In the proposed speed observer, the PW power is selected as the reference model since it is relatively readily available and smooth due to the clamped PW voltage under grid-connected condition. In addition, only the CW current is required to be measured for the estimated PW power of the adaptive model, being simple and easy implemented.

Index Terms—Brushless doubly fed induction generator (BDFIG), grid-connected system, model reference adaptive system (MRAS), speed sensorless control.