Research On Double Six-phase Transverse Flux Permanent Magnet Motor And Its Control System

Transverse Flux Permanent-magnet Motor (TFPM) is a new type of specialmotor with the advantages of high torque density and magnetic decoupling, modularstructure. It becomes a hot research field because of the excellent performance ofunder the condition of low speed high torque density. But TFPM has a bottleneck ofthe large leakage, low power factor, complex structure and large torque ripples inwidely development.In this paper, a disc type characteristics of the new Double six-phase TransverseFlux Permanent-magnet Motor (DSTFPM) is proposed, based on existing research oftransverse flux permanent magnet motor. The experimental platform is buildaccording to the analysis of the magnetic circuit model, prototype structure,3Delectromagnetic field and the control scheme. The main research contents andinnovations are as follows.Based on the models of TFPM and PMSM, the magnetic circuit of the newDSTFPM is analyzed with multi-phase modeling method. Using the equivalentmagnetic circuit method, the mathematical modeling is proposed, includingpermanent magnet, tangential interpolar leakage, radial pole leakage flux and statorwindings and DSTFPM. Then the power factor calculation method is given, and thecauses of TFPM low power factor and improving methods is studied. The theoreticalresearch is foundation to the prototype structure design and control algorithm design.An electric direct drive wheel of new DSTFPM topology structure is proposed,according to the existing TFPM and axial, radial motor topology structure andperformance characteristics. It consists of four stator units and two rotor units. And ithas the disc features and axial combination features. The main structure of DSTFPMis designed in the Solidworks software. A novel design method of main structureparameters as the goal of a maximum torque is put forward, optimizing the designideas of the conventional motor. Then the calculation methods of the main inductance,tip leakage reactance and harmonic leakage inductance are given. The research laidthe foundation for further research of the DSTFPM structure performance.The new structure performance and electromagnetic properties of the DSTFPMare analyzed using finite element analysis software. The effect factors of the leakagemagnetic coefficient of low power factor and the cogging torque are researched, through analyzing the influence of air gap length, thickness and the permanent magnetstator core size on the no-load magnetic flux leakage coefficient, air gap length and amagnetic stripe on the cogging torque. The research provides theory basis to reducethe magnetic leakage of the motor and the torque ripple suppression. Then thesimulation of electromagnetic field distribution and electromagnetic torque ispreceded, verifying the feasibility and rationality of the DSTFPM structure design.Direct Torque Control and Space Vector Modulation (DTC-SVM) is takenbecause it has many advantages. According to the six sectors and the twelve sector ofthe direct torque control of stator flux subdividing method, the algorithm combinationof the eighteen sectors stator flux subdivision method and the duty cycle algorithm isproposed. It can effectively reduce the torque ripple method in control algorithm. It issuitable for the control algorithm applied in simple extensionBased on the experiment platform system, the no-load EMF, static torque andno-load operation characteristics are studied. And the rationality of DSTFPMmathematical modeling, structure design, finite element analysis and the improvedcontrol algorithm is verified by experiments. The achievements of this paper enrichthe topology structure of electric vehicle direct drive in wheel motor and have certaintheoretical significance and application value.