Structure Research and Design of Brushless Doubly-Fed Machine

Having advanced in recent years, brushless doubly fed machine (BDFM) becomes a novel AC variable frequency control machine which has a broad vista of application in wind power generation system. Researchers focus on machine structure presently. Based on accurate analysis of electromagnetism relation, this paper firstly presents double-cage stator core structure in order to improve insulation of power winding and control winding. Non-salient pole rotor core and hidden end collar new rotor structure is also presented. Magnetic field of the new structure BDFM is analyzed and calculated by ANSYS. The results show that new structure obviously advances efficiency of rotor magnetic field pole-number conversion and improves machine operating performance.