Rotor Current Oriented Control Method of DFIG-DC System Without Stator Side Sensors

Abstract

This letter proposes a novel stator power and frequency control method of doubly-fed induction generator (DFIG)-dc system, which is based on rotor current orientation and avoids using stator side sensors. By means of establishing the relationship of the rotor current vector, stator active power, and stator frequency, the stator active power can be controlled by the angle between the rotor current vector and stator voltage vector. The stator frequency can be controlled by the magnitude of the rotor current vector. The stator active power is calculated by dc voltage and dc current at stator side. In this way, the stator voltage and current sensors can both be eliminated. Furthermore, the stator frequency and orientation angle are acquired by the power control loop, which avoids using voltage model or current model. In this way, both parameter dependency and dc sampling uncertainties can be eliminated. Finally, experiments based on a 1-kW DFIG-dc setup were carried out to verify the proposed method.