Passivity-based control of double-fed induction generator under unbalanced grid voltage fault
不平衡电网电压下双馈感应发电机无源控制

To inhibit the imbalance current in the stator and the rotor caused by the unbalanced grid voltage, we propose a passivity control strategy for the double-fed induction generator system (DFIG). On the basis of the passivity of the positive and negative sequence models in the positive synchronously rotating frame, a passivity state feedback controller is first designed. Next, a method for calculating expectation values is developed, by which we calculate the command values for the negative sequence components of the stator current and the rotor current based on the unbalanced control objectives. The command values of the positive sequence components of the stator current and the rotor current are calculated on the basis of positive sequence components of the stator voltage and the expectation values of the electromagnetic torque. Thus, a passive controller for DFIG under unbalance grid voltage condition is designed. Simulation results show that the proposed scheme effectively inhibits the imbalance currents in the stator and the rotor, reduces the output torque fluctuation, and enhances the non-interrupt operation ability of DFIG under unbalanced grid voltages.