Parameter and performance comparison of doubly fed brushless machine with cage and reluctance rotors

The cage and reluctance rotors are two major types of rotor structures used in the doubly fed brushless machine (DFBM). In order to study comparatively the effects of different rotor structure on the DFBM, a prototype machine has been specially designed and built. The experimental parameter and performance comparisons between the axially laminated anisotropic (ALA) and cage-rotor machines are presented. It is found that the cage-rotor DFBM has better starting and asynchronous characteristics; however, the ALA reluctance-rotor DFBM exhibits better synchronous operation and doubly fed adjustable speed performance.