Integrative characteristic evaluation of DFIG maximum power extraction using lookup table approach

A DFIG wind turbine is a variable-speed wind turbine widely used in modern wind power industry. 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 paper presents a DFIG maximum power extraction study through integrated steady-state characteristic and transient close-loop control evaluation approach. The generator characteristics are examined for different d-q control conditions; the peak power tracking and extracted wind power characteristics are presented versus generator slip. Then, all the three characteristics are analyzed in a joint environment to investigate the lookup-table maximum power extraction principle. A nested current- and speed- loop control structure is developed using the stator-voltage-oriented frame, which is then used to evaluate factors that may affect the DFIG peak power tracking control performance. Simulation studies are conducted to investigate how the maximum power extraction is influenced by wind turbine electrical and aerodynamic characteristics as well as different sampling rate and low-pass filtering strategies.