Study on design of Brushless Doubly-Fed Machine with a new type rotor

The brushless doubly-fed machine is a novel AC speed regulation machine developed in recent years, its performance has the relationship with the transformation efficiency of rotor magnetic-field pole numbers. Optimizing the design of rotor structure is the fundamental way to increase the transformation efficiency. By analyzing the salient pole rotor´s characteristics, a new analogous salient pole reluctance rotor was designed. That is to add n(p+q) deep troughs on the basis of common salient pole reluctance rotor structure. Accordingly, the rotor was divided into p+q magnetic poles. It is known from comparative analysis of the motor magnetic field by the finite element method that the new rotor structure works better than the common salient pole rotor in terms of the magnetic poles modulation effect, which increased the magnetic transformation efficiency greatly. The BDFM with new rotor has the advantages of simple structure, easy to manufacture, asynchronous operation in single-fed state, high reliability and high magnetic transformation efficiency.