Modulated Model Predictive Torque and Power Control of Gearless PMSG Wind Turbines

In this paper, novel modulated model predictive toque and power control schemes are proposed for machine- and grid-side converters, respectively in the gearless permanent magnet synchronous generator-based wind turbines. The state variables such as generator torque and flux, and grid active and reactive powers are predicted and evaluated by two independent duty-cycle optimized cost functions. The stationary voltage vectors corresponding to the optimal duty cycles are then synthesized by the space vector modulation to achieve fixed switching frequency operation for the back-to-back connected voltage source converter. With the proposed control schemes, the state variables are controlled precisely with fast transient response and low steady-state errors to accomplish the control goals of wind turbines during a wide-dynamic range operation. The feasibility of the proposed schemes is verified through simulation results using a 750-kW wind turbine system.