Enhancing the characteristics of brushless doubly-fed induction machines using a new rotor circuit
In the presented work, a new rotor circuit is proposed for a brushless doubly-fed induction machine (BDFIM) with 8-/4-pole power/control winding. Using the proposed rotor circuit, the mutual-coupling of the power winding and the rotor circuit, and consequently the cross-coupling between the power and control windings is increased. Therefore, a BDFIM with a higher torque capacity is obtained. A dynamic model is established for BDFIMs and used as a fast tool to investigate and compare the characteristics of the proposed machine with the extant BDFIMs with parallel and series loops. The dynamic model is funded based on the concept of multiple coupled circuits. The machine magnetizing inductances are the parameters of this model and obtained by using the winding function method. The provided dynamic model is validated by means of time-stepping finite element analysis. Finally, it is shown that using the proposed rotor circuit, the cross-coupling of the stator windings is increased. Consequently, the magnetizing current and the Joule losses are decreased in the proposed BDFIM machine.