Design and analysis of a dual-stator brushless doubly-fed induction machine with a staggered dual-cage rotor

In this paper, a new dual-stator brushless doubly-fed induction machine with a staggered dual cage rotor is proposed, with emphasis on the general interconnection rule of the conductor bars for the staggered dual cage rotor. Since the squirrel cage rotor offers the merits of robustness, reliable structure, high slot filling factor, and low rotor resistance comparing to the wound rotor, it is introduced to the dual-stator brushless doubly-fed induction machine to solve the problems of high copper loss and unreliable rotor structure for the dual-stator brushless doubly-fed induction machine with a wound rotor. The originality of this article is to investigate the interconnection rule of conductor bars between the inner and outer cages. The constraint condition that is supposed to be satisfied is deduced by using the rotating magneto-motive force theory, based on which diverse slot/pole combinations are investigated. The performance comparison between the existing and proposed machines is conducted. Finally, a prototype is designed and fabricated. The experimental results verify the effectiveness of the proposed topology.