Certificate for safe emergency shutdown of wind turbines

To avoid damage to a wind turbine in the case of a fault or a large wind gust, a detection scheme for emergency shutdown is developed. Specifically, the concept of a safety envelope is introduced. Within the safety envelope, the system can be shutdown without risking structural damage to the turbine. To demarcate the boundary of the safety envelope, a protection certificate, is computed. To this end, a model-based framework of barrier certificates is used. As a result, the protection certificate problem is formulated as a sum-of-squares program with the optimisation criterion related to the volume of the safety envelope. The framework enables the inclusion of a bounded wind disturbance and the a priori known emergency shutdown procedure. For this purpose, the model of a wind turbine is developed that includes structural safety critical components.