An Improved Control Method for Standalone Brushless Doubly-Fed Induction Generator Under Unbalanced and Nonlinear Loads Using Dual-Resonant Controller

The brushless doubly-fed induction generator (BDFIG) in standalone mode is sensitive to unusual working situations, particularly unbalanced and nonlinear loads. The unbalanced and nonlinear loads can cause significant unbalance and distortion for voltage and current of the power winding (PW). In PW voltage under nonlinear and unbalanced loads, the component of negative sequence represents the unbalance influence, and the 5th and 7th harmonics components represent the nonlinear influence. To address these issues, the dual-resonant controller (DRC) is employed to reduce the unbalance and nonlinear influences of PW voltage via generating the reference command of control winding (CW) voltage which compensate the negative sequence component and 5th and 7th harmonic components of PW voltage through the machine side converter (MSC). The experimental and simulation tests are applied to check the effectiveness of the proposed strategy.