Integral variable structure direct torque control of doubly fed induction generator

This study proposes a novel integral variable structure direct torque control (IVS-DTC) scheme for a doubly fed induction generator (DFIG). The proposed scheme directly controls the torque and reactive power of the DFIG with rotor winding voltage, and hence no extra current control loops are required. Uncertainties in the parameters are included in the design procedure, which guarantees the robustness of the system. Compared to conventional direct torque control (DTC) scheme, the constant switching frequency in the proposed scheme does not introduce low-frequency sub-harmonics. Both computer simulation and hardware implementation results show that proposed scheme has satisfactory parametric robustness and generated power quality.