Articles | Volume 1, issue 2
Wind Energ. Sci., 1, 177–203, 2016
Wind Energ. Sci., 1, 177–203, 2016

Research article 20 Oct 2016

Research article | 20 Oct 2016

Periodic stability analysis of wind turbines operating in turbulent wind conditions

Riccardo Riva1, Stefano Cacciola2, and Carlo Luigi Bottasso1,2 Riccardo Riva et al.
  • 1Dipartimento di Scienze e Tecnologie Aerospaziali, Politecnico di Milano, Milano, Italy
  • 2Wind Energy Institute, Technische Universität München, Garching bei München, Germany

Abstract. The formulation is model-independent, in the sense that it does not require knowledge of the equations of motion of the periodic system being analyzed, and it is applicable to an arbitrary number of blades and to any configuration of the machine. In addition, as wind turbulence can be viewed as a stochastic disturbance, the method is also applicable to real wind turbines operating in the field.

The characteristics of the new method are verified first with a simplified analytical model and then using a high-fidelity multi-body model of a multi-MW wind turbine. Results are compared with those obtained by the well-known operational modal analysis approach.

Short summary
This paper presents a method to assess the stability of a wind turbine. The proposed approach uses the recorded time history of the system response and fits to it a periodic reduced-order model that can handle stochastic disturbances. Stability is computed by using Floquet theory on the reduced-order model. Since the method only uses response data, it is applicable to any simulation model as well as to experimental test data. The method is compared to the well-known operational modal analysis.