Research On Electromagnetic Characteristics And Experiment Of Brushless Doubly Fed Machine With Novel Hybrid Rotor

The Brushless Doubly Fed Machine (BDFM) is an universal AC machine which canoperate reliably and has wide application prospects in the generation fields of variable speedand constant voltage constant frequency?and the adjustable system of large capacity motor.Supported by the China natural science fund and based on Liaoning key scientific andtechnological project, this paper conducted electromagnetic characteristics analysis andexperiments with novel hybrid rotor BDFM. The main research work includes the followingaspects:The paper presents a new hybrid rotor BDFM with powerful coupling capability, which isbased on principles of magnetic field modulation and rotor researching progress, and limitingthe BDFM application because of the lower coupling capability rotor. After comparing thecoupling capability of different rotors and analyzing the field modulation via finite elementmethod, it proved the proposed hybrid rotor has outstanding advantages in the magnetic fieldmodulation capabilityIn order to improve further capability of magnetic field modulation, the rotor parametersare optimized in a systematical way. Using finite element method, the key parameters affectingthe coupling capability are analyzed, such as pole arc factor, amount of magnetic layer, ratioof magnetic to non-magnetic, short-circuit ring, amount of short-circuit set and short-circuitlayers. The parameters are optimized for holding the best coupling capability, which providestheoretical basis for designing and developing novel rotor.In order to study and analyze the static and dynamic characteristics, Electromagneticanalysis and dynamic simulation are analyzed for hybrid rotor of BDFM, Several keyelectromagnetic aspects are analyzed for BDFM, such as using the Energy perturbationmethod to calculate the inductance parameters, conducting Dynamic simulation in generatorand motor modes and comparison of performances for magnetic barrier rotor and hybrid rotorRegarding the complex magnetic fields harmonious of the BDFM, analytical expressionsof air-gap magnetic flux are derived, and the effect of parameters on magnetic flux is analyzed.Poles combination affects the air-gap magnetic field which leads to more complicatedmagnetic flux. Effect of poles combination and Salient poles number on radicalelectromagnetic force is researched, the Selection basis for pole combination is given, which avoids to produce unilateral magnetic force, and it could reduce the vibration and noise.The BDFMs of new hybrid rotor and magnetic barrier rotor share same stator aredesigned and developed at home and abroad for the first time and comprehensive experimentsare carried out.The inductance parameters of two types of rotors are tested and analyzed usingstatic method for inductance. Noload and load tests of motor and generator are done. Resultsof comprehensive experiments for the two rotors prove that the hybrid rotor has strongercoupling capability, excellent load capacity and good performances. And it further proves thatthe analysis scheme for hybrid rotor BDFM is reasonable and correct.