Transient performance analysis of wind-power induction generators

Abstract

A coupled field-circuit simulator for the transient analysis of wind energy conversion systems with a doubly fed induction generator (DFIG) was developed and experimentally validated. Short-term grid disturbance and ride-through analyses were carried out for a 1.7-MW DFIG wind-power conversion system. Two simulation models of the wind-power DFIG were compared to reveal the consequences of the different modeling approaches for the accuracy of transient analysis. The DFIG was represented in the simulator by an analytical two-axis model with constant lumped parameters or by a finite element method-based model. The model of the generator was coupled with a model of the crowbar-protected and direct torque-controlled frequency converter, a model of the main transformer, and a simple model of the grid. In addition, a detailed model of the wind turbine was compared with a simplified model that omits the model of the mechanical part of the wind turbine. The simulator was experimentally validated by a 1.7-MW full-scale measurement set-up. The comparison between the simulated and measured results shows reasonable agreement. The analytical model of the DFIG, however, manifests certain drawbacks that are overcome by using a FEM model. The developed coupled field circuit-based simulator has proved to be capable and reliable for modeling of complicated power electronics and electrical machine set-ups and thus is a useful tool for the development and optimization of wind-power generators.