Research Of The Flux-Torque Regulation Hybrid Excitation Machine With Axial-radial Magnetic Circuit

In order to solve the problem of difficult magnetic field regulation of permanent magnet motors,a novel flux-torque regulation hybrid excitation machine with axial-radial magnetic circuit is proposed in this paper.Different from the traditional DC hybrid excitation motor,the motor realizes the adjustment of the main air gap magnetic field by changing the effective value and phase of the AC excitation source.In addition,its unique magnetic ring structure makes the permanent magnet magnetic field interact with the axial magnetic field to form additional torque,which improves the torque density of the motor,and focuses on solving the problem of torque reduction caused by weak magnetic growth.In this paper,the new motor is taken as the research object,and its working mechanism and electromagnetic performance are studied and verified.Firstly,the topology and working principle of the flux-torque regulation HEM are introduced.On the basis of structural analysis,combined with the magnetic circuit of the motor under different operating conditions,the principle of motor flux regulation is analyzed.By constructing the equivalent magnetic circuit model,the analytical expression of the main air gap flux is derived,and the coupling relationship between the axial magnetic field and the radial magnetic field is revealed.According to the change process of the relative position between the magnetic ring and the rotor,the mechanism of additional torque is introduced,and the analytical formula of multi-magnetic field torque is derived by Maxwell tensor method.Secondly,the finite element model of the flux-torque regulation HEM is established in Maxwell 3D.The electromagnetic characteristics of the motor such as no-load back electromotive force and flux linkage were analyzed and calculated by the finite element method.Afterwards,the adjustment range of back electromotive force,torque,and speed under different excitation magnetic fields is analyzed,which verifies that the new motor can achieve the effect of double adjustment of flux-torque.Third,based on the analysis of the electromagnetic performance of the motor with initial structural parameters,the influence of pole-slot matching on the electromagnetic performance of the HEM is studied.The electromagnetic performance of 10-pole 9-slot,10-pole 15-slot and10-pole 12-slot three motors were compared and analyzed,including winding coefficient,back electromotive force,magnetic adjustment performance,torque performance,etc.,to illustrate that this type of motor has both high torque density and emphasis magnetic ability,and provides a theoretical basis for the optimization design of such motors.Finally,based on the finite element method,the regularity of the influence of the two elements(effective value and phase)of the AC current on the magnetic moment performance is analyzed.On this basis,the optimal effects of the two performances are comprehensively analyzed,and the matching mechanism between the flux-torque performance and the excitation current parameters is determined.Based on the analysis of the motor characteristics,the experimental prototype is processed according to the design parameters and the experiment is carried out to verify the correctness of the simulation analysis.