Research On The Basic Characteristics Of A Novel Hybrid Excitation Doubly Salient Brushless DC Generator

Hybrid excitation doubly salient machine (HEDSM) which maintains the advantages of bothdoubly salient permanent magnet machine (DSPM) and doubly salient electro-magnetic machine(DSEM) has become a new research hotspot of doubly salient machines (DSM). The structure topology,rectifier circuits, capacity of multiple outputs and the armature reaction of a novel HEDSM are studiedin this paper. The study lays a foundation for the theoretical research and practical application of thenovel hybrid excitation doubly salient brushless DC generator (HEDS-BLDCG).The structure topology of the novel HEDSM is introduced first. Structures of the HEDSM underdifferent stator poles are given. Generation modes of the HEDSM are introduced. The positive directionof the excitation current is defined based on the flux control principle. The law of how the excitationcurrent regulates the air gap magnetic field in different part of the HEDSM is analysed. Differentconnections of armature windings and different output patterns of the HEDSM are presented.As the efficiency of the finite element method (FEM) is very low, nonlinear magnetic networkmodels of the machine under different rotor positions are established. Permeances of different parts ofthe machine are investigated. Proper correction factors of permeability are introduced to improve thecalculation accuracy of the models. The equations are developed by loop-flux method and solved byusing Newton’s method. Both finite element analysis and experimental results verify the nonlinearmagnetic network models.As the HEDS-BLDCG owns the structure of multiple outputs, the load characteristics and powercharacteristics of the HEDS-BLDCG under different output modes and different generation modes arestudied. The flux-linkage equation is deduced. The armature reaction of the HEDS-BLDCG is studied.The factors which influence the armature reaction are analysed.A prototype machine of the24/16-poles HEDSM is developed. The measurements of the no-loadcharacteristics and load characteristics of the prototype machine are finished. The experimental resultsverify the theoretical analysis and the finite element method, which confirms that the novelHEDS-BLDCG has great application and research value in the independent generation system.