Developing a 3D-FEM Model for Electromagnetic Analysis of an Axial Flux Permanent Magnet Machine

Recently, many optimal designs for axial flux permanent magnet (AFPM) motors were performed based on finite- element (FE) analysis. Most of the models are based on reduction of 3D problem to 2D problem which is not accurate for design aspects. This paper describes an accurate electromagnetic analysis of a surface mounted, 28 pole AFPM with concentrated stator winding. The AFPM is modeled with three-dimensional finite-element method. This model in-cludes all geometrical and physical characteristics of the machine components. Using this accurate modeling makes it possible to obtain demanded signals for a very high precision analysis. Magnetic flux density, back-EMF, magnetic axial force and cogging torque of the motor are simulated using FLUX-3D V10.3.2. Meanwhile, the model is paramet-ric and can be used for design process and sensitivity analysis.

Research on Torque-Angle Characteristic of Large Gap Magnetic Drive System

The principle and design method of the large gap magnetic drive system is studied in this work. The calculation model of the torque-angle characteristic in the large gap magnetic drive system driven by traveling wave magnetic field is established. The calculation model is computed by using MATLAB software, and the pattern of the system’s torque-angle characteristic is obtained by analyzing study results. These results indicate that: torque-angle characteristic and the driving torque of the system can be adjusted by changing the electric current of coil, the magnetization of permanent magnetic gear, the inner diameter of permanent magnetic gear, the coupling distance between electromagnet and permanent magnetic gear, the outer diameter of permanent magnetic gear, and the axial length of permanent magnetic gear.

The Characteristics Analysis and Cogging Torque Optimization of a Surface-Interior Permanent Magnet Synchronous Motor

This paper proposes optimal stator skewed slot analytical method for cogging torque reduction in surface-interior permanent magnet synchronous motor(SIPMSM)and analyzes the characteristics of SIPMSM.The series-parallel equivalent magnetic circuit models(EMCMs)of SIPMSM is built based on the characteristics of magnetic circuits,which is used to design the basic electromagnetic parameters of SIPMSM.Analytical expressions of cogging torque are derived from applying analytical techniques.Stator skewed slot for cogging torque minimum is adopted,and the stator skewed slot pitch is confirmed based on the analytical expressions of the resultant cogging torque.The cogging torque,torque ripple,back electromotive force(back-EMF),power-angle characteristics,efficiency and power factor of SIPMSM are analyzed by establishing 3-dimensional finite element model(3-D-FED)of SIPMSM with stator skewed slot and straight slot.It is shown that the comprehensive performance of optimized SIPMSM is improved as confirmed by finite element analysis and analytical calculation results.

Torque Characteristics of High Torque Density Partitioned PM Consequent Pole Flux Switching Machines With Flux Barriers

Unique double salient structure of Permanent Magnet Flux Switching Machines(PMFSM)with both Concentrated Armature inding(CAW)and Permanent Magnet(PM)on stator attract researcher's interest for high speed brushless application when high torque density(T den)and power density(P den)are the primal requirements.However,despite of stator leakage flux,high rare-earth PM usage,PMFSM is subjected to slot effects due to presence of both PM and CAW in stator and partial saturation due to double salient structure which generates cogging torque(T cog),torque ripples(Trip)and lower average torque(T avg).To overcomne aforesaid demerits,this paper presents Partitioned PM(PPM)Consequent Pole Flux Switching Machine(PPM-CPFSM)with flux barriers to enhance flux mnodulation,curtail PM usage and diminish stator leakage flux which reduces slotting effects and partial saturation to ultimately reduces T cog and Trip In comparison with the existing state of the art,proposed PPM-CPFSM reduces 46.5390 of the total PM volumne and offer Tavg higher up to 88.8%,suppress Trip naximun up to 24.8%,diminish Tcog up to 22.74%and offer 2.45 times Tden and Pden.Furthermore,torque characteristics of proposed PPM-CPFSM is investigated utilizing space harmonics injection i.e.inverse cosine,inverse cosine with 3rd harmonics and rotor pole shaping techniques i.e.,ecce ntric circle,chanfering and notching.Detailed electromagnetic perfornance analysis reveals that harmonics injection suppressed Tcog maximun up to 83.5%,Trip up to 40.72%at the cost of 4.71%Tavg.Finally,rotor mnechanical stress analysis is utilized for rotor withstand capability and 3D-FEA based Coupled Elctromagnetic Thermal Analysis(CETA)for thermal behavior of the developed PPM CPFSM.CETA reveals that open space along PPM act as cooling duct that inprove heat dissipation.

双调制式轴向永磁齿轮电动机气隙磁场与转矩计算

针对轴向永磁齿轮电动机(Axial Magnetic Gear Motor,AMGM)整体尺寸偏大导致的转矩密度偏低(≤70 kN·m/m^(3))等缺陷,提出了一种双调制式轴向永磁齿轮电动机(Dual-modulation Axial Magnetic Gear Motor,DAMGM)。采用高速侧及低速侧两个调磁环对DAMGM低速转子进行调制,且两个调磁环中的非导磁部分均为永磁体,有效提高了低速转子的输出转矩;另外,与现有AMGM相比,将驱动电动机置于DAMGM高速永磁转子内部,减小了整体轴向尺寸,大幅提高了低速转子的转矩密度(150 kN·m/m^(3))。针对现有3D有限元计算时间长、计算机资源浪费严重等问题,给出一种基于圆柱坐标系的DAMGM三维分析方法。根据调磁环的3种边界条件,建立了调制后DAMGM气隙磁场及电磁转矩的数理模型,不仅计算结果准确(与3D有限元相比,平均计算误差≤5%),而且计算时间短(仅为3D有限元的1/10),便于DAMGM不同参数结构的分析、比较与优化。

无磁轭分块电枢盘式电机齿槽转矩优化设计

为了满足定子无磁轭分块电枢(yokeless and segmented armature,YASA)轴向磁通永磁电机作为车用牵引电机时对输出转矩高平稳性的要求,提出一种基于永磁体径向均匀分段、分组同向偏移的方法来抑制YASA电机的齿槽转矩,以降低转矩脉动。应用三维有限元分析,分别研究了3种不同的永磁体分段方案对齿槽转矩的削弱效果,确定了磁极的最优偏转角度及其对电机综合性能的影响。仿真结果验证了该方法的可行性。YASA电机的齿槽转矩降低了92.62%,额定工况下转矩脉动下降了72.02%,永磁体涡流损耗降低91.28%,同时输出转矩下降不超过5.34%,提高了YASA电机的综合性能。

Torque characteristics in a large permanent magnet synchronous generator with stator radial ventilating air ducts

In this study, we investigated the torque characteristics of large low-speed direct-drive permanent magnet synchronous generators with stator radial ventilating air ducts for offshore wind power applications. Magnet shape optimization was used first to improve the torque characteristics using two-dimensional finite element analysis（FEA） in a permanent magnet synchronous generator with a common stator. The rotor step skewing technique was then employed to suppress the impacts of mechanical tolerances and defects, which further improved the torque quality of the machine. Comprehensive three-dimensional FEA was used to evaluate accurately the overall effects of stator radial ventilating air ducts and rotor step skewing on torque features. The influences of the radial ventilating ducts in the stator on torque characteristics, such as torque pulsation and average torque in the machine with and without rotor step skewing techniques, were comprehensively investigated using three-dimensional FEA. The results showed that stator radial ventilating air ducts could not only reduce the average torque but also increase the torque ripple in the machine. Furthermore, the torque ripple of the machine under certain load conditions may even be increased by rotor step skewing despite a reduction in cogging torque.

分裂齿集中绕组永磁游标电机电磁转矩特性分析

为了研究分裂齿集中绕组永磁游标电机(PMVM)的电磁转矩特性,基于磁场调制原理建立PMVM的磁动势磁导模型,给出永磁体和电枢绕组单独作用下气隙磁密谐波的次数和转速表达式,分析产生平均转矩和转矩脉动的谐波次数。采用麦克斯韦应力张量法计算各主次谐波产生转矩的大小,确定各主次谐波对电磁转矩的影响。通过有限元分析对结果进行了验证。结果表明:PMVM的电磁平均转矩绝大部分由16次谐波产生,占比98.83%,转矩脉动主要由16、34、48次谐波产生,占比52.29%。PMVM电磁平均转矩的来源主要为永磁体产生的气隙磁密基波,因此可改变永磁体的用量和形状增大其产生的气隙磁密基波以提升PMVM电磁转矩性能。

基于多轮进化算法的车用双层磁钢永磁同步电机参数优化设计

针对车用双层磁钢永磁同步电机转矩波动过大的问题,基于进化算法(evolutionary algorithm,EA)对一台应用于混合动力专用变速箱(dedicated hybrid transmission,DHT)的双层磁钢永磁同步电机的转子斜极角、定子槽高、定子槽宽和双层磁钢的宽度和厚度进行了参数优化设计,通过试验设计法(design of experiment,DOE)法对各项参数的灵敏度进行分析,得出参数对优化目标的影响权重和正负相关性,再结合多轮进化算法得出最优参数组合,结果表明优化后的永磁同步电机转矩波动下降了3.5%。此外,采用联合仿真的方式对优化后的永磁同步电机进行了最大转矩电流比(maximum torque per ampere,MTPA)控制仿真,结果表明优化后的电机在高转矩提速阶段转矩波动明显减小,验证了该优化流程的有效性。该仿真流程能够提高优化过程的效率,减少实物测试的次数,降低混合动力专用变速箱的开发成本和开发周期。

基于谐波分析的PMSM齿槽转矩补偿

针对永磁同步电机(PMSM)物理结构存在的固有齿槽转矩脉动会导致电机运行时速度波动的问题,提出了一种齿槽转矩补偿方法。首先,结合齿槽转矩产生的机理,设计了齿槽转矩补偿方法;其次,利用专用设备获取电机齿槽转矩数据,然后结合快速傅里叶变换(FFT)进行谐波分析,在线计算拟合转矩补偿量,对控制器的转矩指令进行补偿,可降低齿槽转矩脉动的影响;最后,对该方法进行了实际的测试验证,结果表明该方法可有效降低伺服电机齿槽转矩脉动引起的速度波动。

异步起动永磁同步电动机齿槽转矩的削弱

由于异步起动永磁同步电动机的定转子双边开槽,增加了其齿槽转矩的特性分析及削弱措施研究的难度,现有针对该类电机齿槽转矩的削弱措施效果有限。首先,基于永磁体单独作用时的气隙磁密分布、定转子开槽引起的气隙磁导函数分布的解析模型,建立了齿槽转矩的解析分析模型;然后,研究了能有效削弱齿槽转矩的电机结构参数确定方法;最后,以一台18.5 kW样机为例,确定了能有效抑制电机齿槽转矩的定子齿宽、转子齿宽。结果显示,与现有削弱措施相比,确定的定子齿宽、转子齿宽能进一步将齿槽转矩削弱46.64%、65.98%,并且不会对电机的运行性能产生显著影响。

无齿靴集中绕组外转子永磁电动机的研究

外转子永磁电机定子齿靴的存在,降低了绕线效率和槽满率,以12槽14极分数槽集中绕组外转子永磁电动机为例,建立了基于Maxwell 2D的瞬态磁场仿真模型,研究了磁极参数和定子齿靴宽度对磁场分布、绕组电势、齿槽转矩的影响,并以最大电动势和最小齿槽转矩为目标,设计了一台无齿靴外转子永磁电动机,样机验证了设计方案的正确性。

14极12槽定子模块化永磁电机的性能分析

永磁电机的定子模块化结构有利于大型电机的制造、运输、组装和维护,对于可模块化且极数多于槽数的电机,定子模块化结构还能提高电机的部分性能。利用有限元软件分析了定子模块化结构对14极12槽永磁电机性能的影响,结果表明,模块化结构对定子磁密、转矩和损耗等参数有影响,可利用合适的模块间隙宽度来提高电机负载转矩并降低转矩脉动。

定转子双开槽对永磁同步电机齿槽转矩的影响

针对内置式永磁同步电机齿槽转矩过高导致的振动和噪声的问题,提出一种定子开矩形槽转子开弧形槽的电机模型,可以在不牺牲输出转矩的情况下抑制齿槽转矩。在分析齿槽转矩的基础上,以8极36槽内置式永磁同步电机为例,通过有限元仿真,分析在定转子上单独开辅助槽以及同时开辅助槽时,电机齿槽转矩随辅助槽参数的变化。然后对优化前后电机的性能参数进行对比,验证了所提方法的可行性。仿真结果表明,齿槽转矩随辅助槽参数的变化先减小后变大,定转子同时开辅助槽时,齿槽转矩削弱了92.01%,相较于单独在定子或转子开槽,可以更好地削弱电机齿槽转矩,且双开槽模型可以更有效地削弱气隙磁密谐波,提高电机的输出转矩。

基于Magnet的磁阻永磁齿轮结构形状有限元仿真研究

介绍了两种结构形式的磁阻永磁齿轮,并对其进行了对比仿真分析,证明了当永磁磁极位于外转子上时,齿轮稳态阶段的速度和传动转矩波动较永磁磁极位于内转子上时小;以永磁磁极位于外转子上的齿轮为对象,研究了从动凸齿的结构形状对齿轮转矩传递能力的影响,得出从动凸齿的结构形状应该外圆心角大于内圆心角,且外圆心角尽量大一点,内圆心角尽量小一点;对齿轮的4种定子连接桥结构形式对转矩传递能力的影响进行了分析,证明了外连接桥可以获得最大传动转矩。

永磁游标电机转矩特性研究

永磁游标电机具有转矩密度高、结构简单等优点,在电动船舶、风力发电等低速大转矩驱动领域应用广泛。为进一步提高永磁游标电机的转矩密度,采用气隙磁场调制理论研究永磁游标电机的转矩特性。通过分析永磁磁场和电枢反应磁场谐波的有效耦合过程,揭示永磁游标电机转矩产生机理。根据电机结构参数与磁动势、磁导分布的关系,确定待优化参数,结合响应面法和遗传算法对电机转矩性能进行多目标优化设计。采用麦克斯韦应力张量法定量分析气隙磁场各次谐波对电磁转矩的贡献。结果表明,永磁游标电机电磁转矩仅由单一气隙磁场工作谐波产生。在此基础上,研究关键结构参数对气隙磁场调制效应和电机转矩性能的影响,为该类电机的拓扑结构创新及其转矩性能提升提供了理论依据。

裂齿式永磁游标电动机性能分析与比较

针对永磁游标电动机(permanent magnet vernier motor, PMVM)转矩密度大和功率密度高的特点,将其与传统永磁同步电动机(permanent magnet synchronous motor, PMSM)的性能进行比较研究.给出了6槽32极裂齿式PMVM的结构及工作原理,采用有限元仿真软件JMAG对其永磁磁场和电枢反应磁场的气隙磁密、空载感应电势、转矩、损耗等进行了分析,并与两台具有相同直径、轴长、定子齿数的PMSM进行了定量比较.结果表明:相比于6槽32极和6槽4极PMSM,6槽32极裂齿式PMVM平均转矩分别增加约45.0%和76.2%,转矩脉动减小约90.5%和95.0%,这揭示了PMVM转矩密度大、转矩脉动小的优点.然而,由于PMVM气隙中含有大量不同极对数、不同旋转速度的谐波磁场,导致其铁耗和永磁体涡流损耗较大.

轴向磁通永磁轮毂电机转矩密度分析

本文从设计角度出发分析轴向磁通永磁轮毂电机转矩密度提高方法,首先推导轴向磁通永磁轮毂电机转矩密度的解析表达式,分析不同拓扑结构转矩密度的优劣,通过定子多环磁路解析法分析轮毂电机中内径、外径等不同位置的齿部、轭部磁密规律。然后通过有限元软件,建立轴向磁通永磁轮毂电机三维仿真模型,分别研究了不同定子裂比、轭高占比、齿宽占比和空载气隙磁密的轴向磁通永磁轮毂电机转矩密度规律,通过试验验证了计算方法的正确性及准确性。

磁力齿轮永磁同步电机齿槽转矩分析

针对磁力齿轮永磁同步电机转矩波动较大的问题,分析影响齿槽转矩的因素,提出了永磁体和调磁块的合理配置能有效抑制齿槽转矩的方法。首先,简述所设计电机的工作原理并给定初始参数。其次,采用解析法得出空载气隙磁密分布,并通过有限元仿真验证理论分析的正确性。最后,参考传统永磁电机削弱齿槽转矩方法,设计两种传动方案,研究永磁体极数和调磁块数的最小公倍数对齿槽转矩周期数的影响,表明增大最小公倍数可有效降低两个转子齿槽转矩幅值。

考虑交叉耦合影响的内置式永磁同步电机电感计算及转矩分析

内置式永磁同步电机的电磁转矩主要包括永磁转矩和磁阻转矩两种成分,转矩成分的准确分离和分析有助于进一步优化设计电机拓扑结构,提高电机的功率密度,而电磁转矩成分精确分析的关键在于交直轴电感的准确计算。该文针对内置式永磁同步电机的交直轴电感求解与转矩成分分析的实际问题,以一台8极11 kW的内置式永磁同步电机为例,对其进行建模仿真计算;通过对采用静磁场求解电感与瞬态场求解电感两类求解电感的方法进行对比分析,在此基础上提出了一种改进的静磁场快速求解交直轴电感的方法,并实现了对电机转矩组成的高精度分离提取和在电磁设计阶段对电磁转矩成分的预测。改进的静磁场求解电感的方法既能精确考虑交叉耦合效应,又能考虑不同负载下饱和效应的影响。此外,相较于瞬态场求解电感的方法,该方法有效减少了仿真步数从而缩短了仿真时长。最后,构建实验测试平台对目标样机进行了转矩测试,并与预测模型结果进行比较,实验结果验证了所提方法的准确性和有效性。