Reduction of Cogging Torque and Electromagnetic Vibration Based on Different Combination of Pole Arc Coefficient for Interior Permanent Magnet Synchronous Machine

Cogging torque and electromagnetic vibration are two important factors for evaluating permanent magnet synchronous machine(PMSM)and are key issues that must be considered and resolved in the design and manufacture of high-performance PMSM for electric vehicles.A fast and accurate magnetic field calculation model for interior permanent magnet synchronous machine(IPMSM)is proposed in this article.Based on the traditional magnetic potential permeance method,the stator cogging effect and complex boundary conditions of the IPMSM can be fully considered in this model,so as to realize the rapid calculation of equivalent magnetomotive force(MMF),air gap permeance,and other key electromagnetic properties.In this article,a 6-pole 36-slot IPMSM is taken as an example to establish its equivalent solution model,thereby the cogging torque is accurately calculated.And the validity of this model is verified by a variety of different magnetic pole structures,pole slot combinations machines,and prototype experiments.In addition,the improvement measure of the machine with different combination of pole arc coefficient is also studied based on this model.Cogging torque and electromagnetic vibration can be effectively weakened.Combined with the finite element model and multi-physics coupling model,the electromagnetic characteristics and vibration performance of this machine are comprehensively compared and analyzed.The analysis results have well verified its effectiveness.It can be extended to other structures or types of PMSM and has very important practical value and research significance.

Five-phase Synchronous Reluctance Machines Equipped with a Novel Type of Fractional Slot Winding

Multi-phase machines are so attractive for electrical machine designers because of their valuable advantages such as high reliability and fault tolerant ability.Meanwhile,fractional slot concentrated windings(FSCW)are well known because of short end winding length,simple structure,field weakening sufficiency,fault tolerant capability and higher slot fill factor.The five-phase machines equipped with FSCW,are very good candidates for the purpose of designing motors for high reliable applications,like electric cars,major transporting buses,high speed trains and massive trucks.But,in comparison to the general distributed windings,the FSCWs contain high magnetomotive force(MMF)space harmonic contents,which cause unwanted effects on the machine ability,such as localized iron saturation and core losses.This manuscript introduces several new five-phase fractional slot winding layouts,by the means of slot shifting concept in order to design the new types of synchronous reluctance motors(SynRels).In order to examine the proposed winding’s performances,three sample machines are designed as case studies,and analytical study and finite element analysis(FEA)is used for validation.

Torque production mechanism of switched reluctance machines with field modulation principle

This paper aims to investigate the torque production mechanism and its improvement design in switched reluctance machines(SRMs) based on field modulation principle. Firstly, the analytical expressions of the air-gap magnetic field are derived from the perspective of DC-and AC-components, respectively. Meanwhile, different slot/pole combinations and winding arrangements are considered. Secondly, the torque productions are analyzed and evaluated with emphasis on the interaction between the DCand AC-components of air-gap fields. Thirdly, the 12-slot/8-pole and 12-slot/10-pole SRMs are established and studied by using the finite-element method. The effects of slot/pole combination and winding arrangement on the average torque production are clarified. Then, two new designs to improve the average torque are proposed. Finally, the prototype of the 12-slot/10-pole SRM is manufactured, and the experiments are carried out for validation.

Analysis and Optimization of a Five-phase Hybrid Excitation Flux Switching Machine Based on the Consistency and Complementarity Principle

In this study,the general optimal stator poles/rotor teeth(P/T)combination equation of the E-core hybrid excitation flux switching(HEFS)machines are introduced,and a new HEFS machine is proposed and optimized.Firstly,the influences of three different P/T combinations(10/18,10/19,and 10/21)on the HEFS machines are investigated with two-dimensional(2D)finite element analyses(2D-FEA).Meanwhile,the consistency and complementarity principle of the armature windings is analyzed in detail to give reasonable explanations to the simulated results.The general optimal P/T combination equation of the E-core HEFS machines is deduced mathematically to provide an effective guidance on the selection of P/T combinations.The optimal P/T combination calculated by the general equation agrees with the simulated results which confirm the correctness of the mathematical inferences.Finally,the optimizations on the proposed HEFS machine are implemented to obtain higher output torque and better flux-regulation ratio characteristics based on which the cogging torque and torque ripple are reduced significantly.