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.

Multi-objective Hierarchical Optimization of Interior Permanent Magnet Synchronous Machines Based on Rotor Surface Modification

To solve the problem of large torque ripple of interior permanent magnet synchronous motor(IPMSM),the rotor surface notch design method was used for V-type IPMSM.In order to accurately obtain the optimal parameter values to improve the torque performance of the motor,this paper takes the output torque capacity and torque ripple as the optimization objectives,and proposes a multi-objective layered optimization method based on the parameter hierarchical design combined with Taguchi method and response surface method(RSM).The conclusion can be drawn by comparing the electromagnetic performance of the motor before and after optimization,the proposed IPMSM based on the rotor surface notch design can not only improve the output torque,but also play an obvious inhibition effect on the torque ripple.

Analysis of temperature field for a surface-mounted and interior permanent magnet synchronous motor adopting magnetic-thermal coupling method

Aiming at obtaining high power density of surface-mounted and interior permanent magnet synchronous motor(SIPMSM),it is important to accurately calculate the temperature field distribution of SIPMSM,and a magnetic-thermal coupling method is proposed.The magnetic-thermal coupling mechanism is analyzed.The thermal network model and finite element model are built by this method,respectively.The effects of power frequency on iron losses and temperature fields are analyzed by the magnetic-thermal coupling finite element model under the condition of rated load,and the relationship between the load and temperature field is researched under the condition of the synchronous speed.In addition,the equivalent thermal network model is used to verify the magnetic-thermal coupling method.Then the temperatures of various nodes are obtained.The results show that there are advantages in both computational efficiency and accuracy for the proposed coupling method,which can be applied to other permanent magnet motors with complex structures.

Multi-Objective Optimization of Surface-Mounted and Interior Permanent Magnet Synchronous Motor Based on Taguchi Method and Response Surface Method

The surface-mounted and interior permanent magnet synchronous motor(SIPMSM)has the characteristics of multiple variables,strong coupling and nonlinearity.In order to improve the performance of SIPMSM,this paper presents a multi-objective optimal design process using Taguchi and response surface methodology(RSM).The peak value of cogging torque(PVCT),ratio value of average torque and permanent magnet weight(RTW),torque ripple and back-EMF total harmonics distortion(ETHD)are selected as optimization goals.The experiment matrix is established by Taguchi method,and analyzed the tendency and proportion of the effect of the optimization parameters on SIPMSM performance.The rules of choosing multi-objective optimization parameters are obtained.The least-squares method is used to establish the optimal objective function,and RSM is used to obtain the resolutions of the optimization objective function.Comparing the initial performance with optimized performance verifies the effectiveness of the proposed method.

Quantitative Comparison of Electromagnetic Performance of Electrical Machines for HEVs/EVs

In this paper,various types of sinusoidal-fed electrical machines,i.e.induction machines(IMs),permanent magnet(PM)machines,synchronous reluctance machines,variable flux machines,wound field machines,are comprehensively reviewed in terms of basic features,merits and demerits,and compared for HEV/EV traction applications.Their latest developments are highlighted while their electromagnetic performance are quantitatively compared based on the same specification as the Prius 2010 interior PM(IPM)machine,including the torque/power-speed characteristics,power factor,efficiency map,and drive cycle based overall efficiency.It is found that PM-assisted synchronous reluctance machines are the most promising alternatives to IPM machines with lower cost and potentially higher overall efficiency.Although IMs are cheaper and have better overload capability,they exhibit lower efficiency and power factor.Other electrical machines,such as synchronous reluctance machines,wound field machines,as well as many other newly developed machines,are currently less attractive due to lower torque density and efficiency.

Fast Calculation of Electromagnetic Forces in IPMSMs Under PWM VSI Supply Based on Small-Signal Time-Harmonic Finite Element Method

This paper introduces a novel method for fast calculating the electromagnetic forces in interior permanent magnet synchronous machines(IPMSMs)under pulse width modulation(PWM)voltage source inverter(VSI)supply based on the small-signal time-harmonic finite element analysis(THFEA),which has been successfully utilized for fast calculating the PWMinduced losses in silicon steel sheets and permanent magnets.Based on the small-signal THFEA,the functional relationships between high-frequency harmonic voltages(HFHVs)and corresponding airgap flux densities are established,which are used for calculating the flux density spectra caused by each HFHV in the PWM voltage spectra.Then,the superposition principle is applied for calculating the flux density spectra caused by fundamental currents and all HFHVs,which are converted to the electromagnetic force spectra at last.The relative errors between the force density spectra calculated with the proposed method and those obtained from traditional time-stepping finite element analysis(TSFEA)using PWM voltages as input are within 3.1%,while the proposed method is 24 times faster than the traditional TSFEA.

Lumped-Parameter Thermal Network Model and Experimental Research of Interior PMSM for Electric Vehicle

A 25kW interior permanent magnet synchronous machine(IPMSM)applied to the electric vehicle is introduced in the paper.A lumped-parameter thermal network model is presented for IPMSM temperature rise calculation.Furthermore,a 3D liquid-solid coupling model considering the assembly clearance is compared with the 2D lumped-parameter thermal network model.Finally,a dynamometer platform for temperature rise measurement is established to verify the above-mentioned methods,which obtains the measured efficiency map at rated load case and overload case.At the same time,the measured no-load back electromotive Force(EMF),load line input voltage and load current are gathered.Thermocouple PTC100 is used to measure the temperature of the stator winding and iron core,and the FLUKE infrared thermal imager is applied to measure the surface temperature of PMSM and controller.Testing result shows that the lumped-parameter thermal network have a high accuracy to predict each part temperature.

基于凸极效应的永磁同步电机振动分析

凸极率的改变会给齿槽转矩带来影响,同时相比较表贴式的结构,其更复杂的结构所带来的谐波也对电机的减振带来巨大的冲击。针对凸极效应所产生的问题,本文基于理论分析以及Ansys有限元仿真平台,对一台具有凸极效应的车用永磁同步电机进行研究,对不同凸极率对电机齿槽转矩以及径向电磁力密度进行对比分析。其次,对三维结构的定子冲片模态进行分析,讨论了可能产生共振的频率。最后,将径向电磁力与有限元模型相耦合,对电机的电磁力引起的振动进行谐响应分析,为车用永磁同步电机的凸极率选择和优化设计提供参考价值。

基于极限学习机的永磁同步电机MTPA 控制方法研究

内置式永磁同步电机参数会随电机运行于不同工况而发生变化,这将影响电驱系统的控制精度及稳定性,为此需要对电机参数进行在线辨识。通过I_(d)=0及d轴注入反向电流得到关于电阻、磁链、电感的满秩方程组,构造出极限学习机算法辨识的电机数学模型。利用极限学习机算法在线辨识电机参数,其结果应用于永磁同步电机MTPA控制系统中,在电驱系统不同工况下运行,测试系统的动静态性能。仿真实验结果表明:在不同的工况下,永磁同步电机电驱系统的转速、转矩、电流动态响应快,稳态脉动小,系统鲁棒性高。

混合励磁同步电机及其控制技术综述和新进展

混合励磁同步电机(hybrid excited synchronous machine,HESM)是一种宽调速电机,它结合了永磁同步电机和电励磁同步电机的优点,又克服了它们各自的缺点。因此,它在宽速度运行范围的风力发电系统和电驱动系统具有广阔的应用前景。该文主要论述了混合励磁同步电机的基本特点,分析了几种典型的混合励磁同步电机的结构及工作原理,提出了一种新的混合励磁同步电机拓扑结构。在此基础上,推导了混合励磁同步电机的数学模型。基于分区控制策略,在低速区和高速区,分别研究了几种混合励磁同步电机控制技术,并对这些技术做了详细比较。针对目前混合励磁同步电机控制技术存在的不足之处,提出了一种新的效率最优控制策略。最后,给出了混合励磁同步电机及控制技术的发展趋势,展望了它的应用前景。

内置式永磁同步电机无位置传感器控制

针对无位置传感器内置式永磁同步电机(interior permanent magnet synchronous motor,IPMSM)矢量控制系统,通过将滑模观测器和高频电压信号注入法相结合,提出一种可实现在宽调速范围获取准确转子位置信息的混合观测方案。设计基于扩展反电动势模型的滑模观测器,对高频信号注入的滤波器和软件锁相环进行研究,并给出混合观测器的切换控制方法,以保证切换过程锁相环跟踪的同步性。针对无传感器IPMSM系统起动困难的问题,研究了一种初始位置估计方法,先注入高频信号检测磁极位置,再注入脉冲电压矢量来判断极性。最后通过IPMSM无位置传感器矢量控制系统验证了该控制策略的有效性。

混合励磁同步电机发展现状及应用前景

针对现有混合励磁同步电机的结构及其特点,简述了混合励磁同步电机的工作原理,并根据其拓扑结构对现有混合励磁同步电机进行了分类,提出了现有混合励磁同步电机的适宜结构形式,指出了其应用前景。

内置式永磁同步电机弱磁调速控制

在对内置式永磁同步电机数学模型深入研究基础上,提出了一种最优弱磁路径控制策略,该控制策略是基于由直轴电流Id和交轴电流Iq所构成的状态空间,以最大电流曲线、最大磁链曲线和最小磁链转矩比曲线为边界而提出的一种最优弱磁路径。该控制策略以实现在电机任何转速下输出力矩范围最大化和电机电枢电流最小化为目标,指出了电机在各种转速下的力矩控制方法,充分挖掘电机的自身潜能,有效保证高速高精型数控机床的加工运行。仿真和实验研究表明,该控制策略可以大大提高电机的调速范围,同时保证转矩有良好的可控性。

电动汽车用IPMSM直接转矩控制系统效率优化

为提升电动汽车续航里程,提出一种车用内置式永磁同步电动机(IPMSM)直接转矩控制系统的在线效率优化方法。首先分析IPMSM的铜损和铁损,并将控制器损耗归入铜损,以全面考虑IPMSM驱动系统的电磁损耗。同时推导了铜损和总电磁损耗随定子磁链变化规律,并在此基础上,得到一种适用于电动汽车频繁变速运行的分区式效率优化方法。该方法利用离散化思想,根据转速和转矩将电动机运行范围分为不同区间,并在各自区间内单独作寻优搜索。所述方法对寻优算法依赖性小,实验结果验证了该在线效率优化方法的有效性和可行性。

切向结构永磁同步电机极对数的选择

对于具有“聚磁”作用的切向结构永磁同步电机,增加极对数可以提高气隙磁密,使得电机体积减小、重量减轻,效率、转矩增大,但极对数的增加存在一个较为合理的值.本文定义了切向结构永磁同步电机“聚磁”的概念,并利用有限元分析软件讨论了极对数与气隙磁密、每极磁通、空载电势、转子导磁体磁密等物理量之间的关系.结论：（1） 计及导磁材料饱和的情况下, 气隙磁密和总磁通随极对数的增加存在一个最大值,即存在一个合理的极对数;（2） 用气隙磁密Bδ与稀土永磁体的内磁感应强度BM之比来表示聚磁作用的程度时,极对数大于等于3时,电机具有聚磁能力;用Bδ与稀土永磁体的剩磁感应强度Br之比来表示聚磁作用的程度时,仅当极对数大于等于4时,切向结构永磁电机才显现出聚磁现象;（3） 切向结构永磁电机极对数在3～6时较为合适.

新型并列式混合励磁无刷直流电机结构原理及其磁场调节特性

基于永磁同步电机和电励磁双凸极电机的有机组合,提出一种并列式混合励磁无刷直流电机。给出永磁同步电机和电励磁双凸极电机的定转子槽极数匹配原则,讨论了直接串联方式下的电枢绕组结构形式,包括一种具有容错能力的定子结构和绕组连接方式。利用二维有限元法分析两类电机基本运行特性,并进一步对整个并列式混合励磁无刷直流电机进行了三维有限元瞬态场分析。研究结果表明,该并列式混合励磁电机实现了两类不同原理无刷电机的高效并列运行,结构简单可靠,气隙磁场易于双向调节,对于永磁电机部分内部绕组故障短路可以有效灭磁,在飞机电源起动发电等场合有重要应用价值。

新型混合励磁永磁同步电机齿谐波电动势的协调控制

对于利用齿谐波磁场来励磁的混合励磁永磁同步电机,希望转子齿谐波绕组中感应的用来励磁的齿谐波电动势足够大,而定子电枢绕组中感应的影响电动势波形的齿谐波电动势尽可能小。为了实现这一目标,分析了齿谐波电动势产生的机理,找到了影响定、转子绕组齿谐波电动势大小的主要因素,并进行了详细的讨论,得出了一些实用的结论。最后,对一台齿谐波励磁的混合励磁永磁同步发电机进行了理论计算和实验,计算结果和实验结果的比较验证了理论分析的正确性。

基于无滤波器方波信号注入的永磁同步电机初始位置检测方法

针对无位置传感器内置式永磁同步电机(IPMSM)初始位置检测中,传统的基于凸极跟踪的短脉冲电压注入法难以确定脉冲宽度和幅值、实现困难、二次谐波分量法信噪比低的缺点,提出一种基于无滤波器方波信号注入的IPMSM初始位置检测方法。首先通过向观测的转子d轴注入高频方波电压信号,采用无滤波器载波信号分离方法解耦位置误差信息,通过位置跟踪器获取磁极位置初定值;然后基于磁饱和效应,通过施加方向相反的d轴电流偏置给定,比较d轴高频电流响应幅值大小实现磁极极性辨识;最后,通过2.2k W IPMSM矢量控制系统对提出的基于无滤波器方波信号注入的初始位置检测方法进行实验验证。结果表明,所提方法收敛速度较快,可在IPMSM转子静止或自由运行状态实现初始位置辨识和低速可靠运行,位置观测误差最大值为6.9°。

表面-内置式永磁转子同步电机等效磁路法特性分析

针对有限元法计算分析电机的复杂性和耗时长等特点,采用等效磁路法分析一种表面-内置式永磁转子同步电机工作特性。建立电机开路状态表面式与内置式永磁体串并联励磁结构等效磁路模型,根据表面-内置式永磁转子磁路结构特点,得到开路状态简化等效磁路模型,计算电机励磁磁场分布、电枢绕组反电势和磁通链;分别建立电机电枢反应下直轴和交轴简化等效磁路模型,求解电机负载磁场分布、电枢反电势和输出电磁转矩;建立电机有限元模型,分析求解电机开路和负载状态电磁特性;建立试验平台,进行试验样机空载和负载测试试验。对比分析简化等效磁路模型、有限元模型计算结果和试验样机测试结果,验证了所提出的等效磁路模型的正确性与合理性。

齿谐波绕组感应电动势波形快速计算

为了把握齿谐波励磁系统的性能,需要快速地计算齿谐波绕组感应电动势波形。通过分析定子齿谐波磁导以及转子齿谐波绕组节距的特点,对转子齿谐波绕组的感应电动势波形计算提出进一步简化,并分析简化原理。简化后只需计算1/2个定子齿距内定转子不同位置下的电磁场,根据电磁场计算结果,得到转子齿谐波绕组磁链在一个周期内的波形,从而快速计算出转子齿谐波绕组感应电动势波形和有效值。该方法具有计算准确、计算量小以及物理概念清楚等优点。对一台齿谐波励磁的混合励磁永磁同步发电机进行了计算和实验,计算结果和实验结果的比较验证了方法的正确性。