Dynamic Event-Triggered Torque Control for Variable-Speed Wind Turbines with Unknown External Disturbances

This paper focus on torque control problems for variable-speed wind turbines with unknown external disturbances. First, a dynamic event-triggering scheme is designed to avoid continuous-time updates of electromagnetic torque. A dynamic variable is introduced and incorporated into event-triggering conditions, which can effectively increase inter-event times than static event-triggering schemes. Furthermore, the unknown external disturbances are regarded as extended states of wind turbine systems, which can be observed by extended state observers. To resist the unknown external disturbances in wind turbine systems, an extended state observer-based control strategy is designed. Both linear and nonlinear extended state observers are developed, where the nonlinear extended state observers have more ideal transient process compared to linear extended state observers. Some studies on a Co-Simulation System Test Bench illustrate that the proposed control strategy can effectively mitigate the impact of unknown external disturbances and guarantee the optimal rotor speed tracking performance for wind turbine systems.