Predictive direet torque control strategy for surfaee-mounted permanent-magnet synchronous generators

This paper proposes a predictive direct torque control (PDTC) technique for surface-mounted permanent-magnet synchronous generators (PMSGs) in variable-speed wind turbine applications. A discrete-time model to predict the future performance of the PMSG is developed and a cost function to selected the optimal switching state from a finite number of states is formulated. The control variables are the torque and d-axis current of the PMSG. Therefore, the proposed PDTC is simple in comparison with the conventional PDTC where the control variables are the torque and stator flux. Furthermore, the maximum torque per ampere scheme can be easily achieved using the proposed PDTC. The proposed PDTC is experimentally implemented and its performance is investigated at various operation conditions and under variations of the PMSG parameters.