Doubly Fed Induction Generator Maximum Wind Power Extraction Study Through Integrated Steady-state and Close-loop Control Evaluation

Abstract

A doubly fed induction generator wind turbine is a variable-speed wind turbine widely used in the modern wind power industry. Unlike a fixed-speed wind turbine, the maximum power extraction of the turbine is affected by (1) electrical characteristics of the generator, (2) aerodynamic characteristics of the turbine blades, and (3) maximum power extraction control strategies. This article presents a doubly fed induction generator maximum power extraction study through the integrated steady-state and transient close-loop control evaluation approach so as to benefit the development of enhanced peak power tracking control techniques for variable-speed wind turbines. The generator characteristics are examined for different d-q control conditions; the peak power tracking and extracted wind power characteristics of the turbine blades versus generator slip are presented. Then, all three characteristics are analyzed in a joint environment to investigate doubly fed induction generator maximum power extraction principles. A nested current- and speed-loop control structure is developed using the stator-flux-oriented frame, which is then used to evaluate factors that may affect doubly fed induction generator peak power tracking control performance. Simulation studies are conducted to investigate how doubly fed induction generator maximum power extraction is influenced by wind turbine electrical and aerodynamic characteristics, different peak power tracking control designs, and variable and gusting winds.