Investigation and Correction on Transformation Angle deviation of Brushless Doubly-fed Stand-alone Generation System

Vector control researches of brushless doubly-fed induction generator (BDFIG) highly depend on the unified-reference-frame dq model, which requires that the coordinate transformation angles and the initial rotor position angle meet the specific relation, otherwise the practical closed-loop control performances will be influenced. To meet the requirement directly, this paper first illustrated the influence of transformation angle deviation on the critical inner-loop control, and then proposed the model-reference-adaptive (MRA) transformation angle correction method for BDFIG stand-alone generation system. Based on the commonly used dual-loop controller under control-winding current orientation, the steady-state adjustable model of control-winding voltage was constructed, and then the transformation angle correction was realized based on adaptive adjustment. The simulation results verified the influence analysis, and the experimental results verified the effectiveness of the proposed angle correction method.