Passive Control for Brushless Doubly-Fed Reluctance Generator Under Unbalanced Grid Voltages

To tackle issues like unbalanced currents in stator windings and power pulsations under unbalanced grid voltage conditions, this paper introduces a passive control strategy for the Brushless Doubly-Fed Reluctance Generator (BDFRG). The approach effectively suppresses current distortions in the stator windings, as well as second harmonic pulsations in the active and reactive power. First, the positive and negative sequence equations of the BDFRG are established using the symmetric component method. Then, passive feedback controllers are designed for both positive and negative sequences by using the Euler-Lagrange (EL) model and the passivity theory. Finally, the given values of the positive and negative currents of the power winding and control winding are calculated to obtain the passive feedback controllers for the BDFRG under unbalanced grid voltages. Simulations and hardware-in-the-loop (HIL) experiments are conducted to validate the correctness of the derived model and assess the effectiveness of the control strategy.