Research On Disk Transverse-flux Permanent Magnet Brushless Machine With Soft Magnetic Composite

The disk transverse-flux permanent magnet brushless machine(DTFPM)is a synthesis of axial magnetic field permanent magnet(PM)machine,transverse-flux PM one and fractional-slot concentrated-winding PM one which features short axis,thin type,high torque density and power density,high fault tolerance and independent electromagnetic load settings.However,if using laminated silicon steel material as its stator core,the motor has a high leakage and high torque ripple,affecting its promotion and application.Soft magnetic composite material(SMC)is a new type of magnetic material,which has excellent characteristics,such as 3-D isotropy ferromagnetism,compression molding,low iron loss at high frequency,high material utilization and high dimensional precision.SMC DTFPM is a novel one with SMC stator material instead of laminated silicon steel,which provides several ways to effectively reduce magnetic leakage and torque ripple.At present,there's little research on whether DTFPM or SMC-based machine,and SMC DTFPM research report has never been found.Therefore the study of SMC DTFPM has important practical value and theoretical significance.The main contents are as follows:Firstly.the background and significance of this research is described and the research status of what is related to SMC DTFPM is reviewed,including disk PM one,transverse-flux PM one,DTFPM and SMC-based machine.And then main contents are given succinctly.Secondly,a novel SMC DTFPM is proposed and its structure principle and superiority are introduced.In particular,the application of SMC materials compared with the laminated silicon steel material provides more ways to reduce the leakage coefficient and torque ripple.For example,add SMC fan-shaped tooth or further misalign the upper and lower tooth.Moreover,keep stator body material unchanged and only add SMC tooth to offset lower SMC permeability.And at the same time,improvement of leakage flux and torque ripple is also verified by 3-D FEM.And then several general research methods,analytic method,magnetic circuit method and finite element method,are compared to select the best suitable one for the above motor.Consequently,magnetic circuit method is selected to act the main one to design and study the motor and finite element method is used for verifying and modifying.Thirdly,the magnetic network of SMC DTFPM is bulit,based on which the performance parameters such as no-load permanent magnet phase electromotive force waveform and load torque waveform are calculated.There are several parts.(1)The calculation formula of the reluctance and potential of all kinds of magnetic circuit in the network is deduced,such as reluctance of the permanent magnet itself,the permanent magnet leakage circuit and the stator pole,magnetic potential of permanent magnet and the stator winding and so on.(2)Ignoring stator saturation,the magnetic circuit model applying only one PM and changing with the relative position of the stator and the rotor is bulit,basing which the universal magnetic network suitable for all PMs and considering stator saturation is obtained by analyzing networks of various special rotor positions.(3)The node magnetic field equations are established and solved,and then load and no-load characteristics are further calculated,such as permanent magnet linkage,permanent magnet electromotive force,load linkage,output torque and magnetic density distribution.(4)Check the established magnetic network and its calculating method with 3-D FEM.Fourthly,electromagnetic calculation program and computer aided design programthe of the SMC DTFPM are studied,namely the above-mentioned magnetic network theory is realized by programming the graphical user interface(GUI)in MATLAB and calculating fill factor,current density,efficiency and other key parameters in the interface,effectively making the machine parameters a quick input and performance parameters a clear output.Then,machine design work is carried out using the established interface and under the power,efficiency and voltage requirements.With the finite element simulation verification and adjustment,the final prototype is achieved.Lastly,make a conclusion of the whole article.