A new rotor type of cascaded brushless doubly-fed machine

In this paper, the squirrel-cage rotor structure of cascaded BDFM is proposed, which can be used to improve the complex connection of wound rotor windings. In order to illuminate the connection mode of two squirrel-cage rotors conductors, the principle of slot star diagram is used and some combinations of different slots and poles are presented as examples. Furthermore, in order to prove the feasibility of the squirrel-cage rotors structure, finite element method of ANSOFT is also employed to analyze the EMF waveform and the magnetic field distribution.