ROTOR MODELING AND DEVELOPMENT FOR BRUSHLESS DOUBLY-FED MACHINES

ABSTRACT

The basic principles of brushless doubly-fed machine (BDFM) synchronous operation are used to establish the essential components of the rotor configuration and alternative types of construction are examined. Certain forms, which appear to be physically realizable only with wound or fabricated rotors, are dismissed in favor of others which may be fabricated or die-cast in a manner similar to the cage rotors of conventional induction machines.

A detailed simulation model is used to predict the performance of a proof-of-concept laboratory machine in a motoring mode which has been correlated with test data. Various developments and options of the rotor configuration are then examined for relative performance at two different speeds using the modeling techniques. The design features considered include (i) alternative interpretations of the nested-loop configuration requirement, (ii) number of rotor loops per nest, (iii) location (span) of rotor loops, and (iv) conductor section of specific rotor bars and end rings.