Model predictive direct torque control for grid synchronization of doubly fed induction generator

A novel model predictive direct torque control (MPDTC) is proposed in this paper to achieve soft and fast grid synchronization for doubly fed induction generator (DFIG). This method is based on the direct control of a virtual torque and the rotor flux, which selects the optimal rotor voltage vector through an evaluation of a cost function. Neither PI regulator nor grid voltage measurement is needed for the MPDTC and only the information of grid voltage, rotor current and rotor position are necessary. The influence of one-step delay caused by digital implementation is also investigated in this paper. The MPDTC is compared with the switching-table-based direct torque control (STDTC) and exhibits better performance in terms of lower ripples in torque and flux, less rotor current harmonics and lower switching frequency. The presented simulation results verify the effectiveness of the novel method.