Rotor-Speed Stability Improvement of Dual Stator-Winding Induction Generator based-Wind farms By Control-Windings Voltage Oriented Control

This paper studies the rotor-speed stability improvement of dual stator-windings induction generator (DWIG)- based wind farms under power system fault conditions. The characteristics of the DWIG based wind turbines are described. The factors affecting the rotor-speed stability are analyzed and a novel control-winding voltage oriented drive together with braking resistor (BR) is proposed to control both the active and the reactive power of DWIG during the fault. The proposed control method provides additional supplementary control loop to conventional control-winding voltage oriented drive. The supplementary control loop devoted to adjusting the BR value in such a way that the whole kinetic energy of generator and turbine is absorbed by BR. Additionally, the orientation of control winding voltage forces the slip of DWIG to be approximately constant, thereby limiting the reactive power consumption during the fault. The simulation and experimental works from the prototype of 1.2-kW three/threephase DWIG wind power system demonstrate the effectiveness of the control scheme as also the significant influence of BR for improving the rotor -speed stability of DWIGs.