Comparison of System Identification Techniques for Predicting Dynamic Properties of Large Scale Wind Turbines by Using the Simulated Time Response

Abstract

Accurate prediction of the dynamics of large wind turbines in state-space model is very important in analyzing the aero-elastic stability problem which is known as one of the design issues associating with increase in size of wind turbines. In this work, two different system identification techniques known as Least Square Complex Exponential (LSCE) method and Sub-space System Identification (SSI) will be investigated in terms of their efficiencies in predicting the dynamic characteristics of a wind turbine blade by using the simulated responses of a reference wind turbine. The results obtained through two different methods are then compared in order to discuss their performance and sensitivity to the simulation data and identification parameters. It shows that these two methods are able to identify the frequencies and damping ratios of the aero-elastic modes for large wind turbine blade when the time domain data set contains enough number of cycles.