Investigation Of High-Voltage Wound-Rotor Brushless Doubly-Fed Machine Frequency Control System

The Brushless Doubly-Fed Machine(BDFM) is a novel induction machine,having a single motor structure,the stator windings are made up of two different rotor polar logarithmic windings and the rotor winding have a special structure,which can couple the power winding and control winding.The structure of the BDFM is similar to traditional cage asynchronous machine and the BDFM has some advantages for its simple structure,robustness,reliability and avoids the use of brush and silp ring.BDFM has the characteristics of less capacity inverter,low control voltage,separately adjustable active power,low system cost,improves performance indicators.The thesis mainly studies the variable-Frenquency adjustable-speed system of BDFM.Beginning with the operating the basic structures of stator and rotor,the paper presents the BDFM’s calculating model.According to the coordinate transform theory,the paper deduced the BDFM’s dual synchronous coordinate mathematical model.In order to improve the stability of V/f controlled BDFM drive system in light load condition, stabilizing control method is presented, which separates the current into fundamental component and harmonics component.Based on stator synchronous coordinate,the voltage and current of stator winding are decoupled,though adjusting the control voltage amplitude to keep stability.And control block diagram and simulation are presented.The method is parameter independent and robust.the oscillations have been suppressed effectively,and the system stability in light load condition is much improved.At last the paper shows the experimental platform of high-voltage brushless doubly-fed machine prototype, prototype experiment results of the was given and analysised.The research in the thesis have an actual meaning to the frequency conversion timing system of BDFM,and will promote the BDFM.