Small signal stability improvement of a wind turbine-based doubly fed induction generator in a microgrid environment

Microgrid concept provides an appropriate context for installing distributed generation resources and providing reliability and power quality for sensitive loads. However, presence of intermittent energy resources like wind turbines and solar cells may affect the microgrid performance due to the close production and consumption levels. In this paper, model of a wind turbine equipped with a doubly fed induction generator system is presented which is capable of operating in islanded mode by decentralized power control method based on active power-frequency and reactive power-voltage droop characteristics. Using this precise modeling approach, small signal stability of the entire system is assessed and then improved based on eigenvalue analysis. Particle Swarm Optimization algorithm is used to enhance the stability margin as well as damping ratio of critical modes. Through simulation in a sample microgrid environment, accuracy of the proposed control method and the optimization process is verified.