Modeling and Analysis of Brushless Doubly-Fed Induction Machine by Magductance

This article aims to theoretically investigate general design and optimization guidance on the short-circuited coils (SCC) modulator in the brushless doubly-fed induction machine (BDFIM). To achieve the target, the concept of magductance is introduced into the SCC modulator. The modulation effect of various rotors on BDFIM performance is directly reflected in the magductance parameter. The modulation effects of the SCC modulator on magnetomotive force (MMF) amplitude and phase are revealed and quantitatively expressed by the magnetic field conversion factor and phase shift. The impacts of various modulator parameters are investigated, and recommendations for their selection are summarized. Based on this, an improved rotor is proposed. Finally, two prototypes are manufactured, and the proposed rotor is validated through analytical calculations and comparisons with existing optimum rotors by finite element analysis (FEA) and experimental results.