Optimal design of brushless doubly-fed machine with unequal-distance conductor rotor structure

ZHENG Ling-juan， CHEN Jian-sheng， ZHANG Wei
（Department of Electrical Engineering， Zhejiang University， Hangzhou 310027， China）

Abstract： As brushless doubly-fed machine （BDFM） is designed with special structure，the harmonic contents of BDFM are high. In order to research the relationship of rotor conductor distribution and BDFM's harmonic contents，winding function of the squirrel-cage BDFM was applied to analyze the effect of rotor conductor distribution to harmonic contents；and the relationship between the conductor distribution and harmonic contents was obtained；then the theoretical analysis of three different kinds of rotor structure was proposed. In the end， Ansoft finite element analysis software was applied to build different rotor structure， and their harmonic contents were compared. The result shows that the intensive-inner rotor conductor distribution structure has better effectiveness to restrain BDFM's useless harmonic wave， and improves the contents of basic wave and useful harmonic wave， which provides a good direction in BDFM's further optimization.
Key words： brushless doubly-fed machine（BDFM）； unequal-distance conductor；winding function； harmonic magnetic field； finite element analysis design