Symbolic Solution Approach to Wind Turbine based on Doubly Fed Induction Generator Model

This paper describes an alternative approach based on symbolic computations to simulate wind turbines equipped with Doubly–Fed Induction Generator (DFIG). The actuator disk theory is used to represent the aerodynamic part, and the one-mass model simulates the mechanical part. The 5th–order induction generator is selected to model the electric machine, being this approach suitable to estimate the DFIG performance under transient conditions. The corresponding non–linear integro-differential equation system has been reduced to a linear state-space system by using an ad-hoc local linearization This novel Symbolic Computation (SYMB) method has been implemented by using two different software-packages, with the purpose of solving simultaneously a remarkable number of individual wind turbines models submitted to different wind speed profiles and/or grid voltage waveforms.
The obtained results are compared with traditional Finite Difference Discretization (FDD) methods, widely proposed for this type of studies. The results offer a good agreement between the proposed SYMB method and the FDD solutions, considering variations of both wind speed profiles and electrical transient events.