正弦磁势作用下单边开槽时气隙比磁导的数值计算

本文用有限元法对单边开有开口槽,每极下为9槽,气隙两边加有正弦谐波磁势时的气隙磁场进行了仔细的数值计算,得到了ν=1,3,5,7,9次磁势作用下的零阶至三阶气隙磁导曲线,供设计和研究工作者使用.研究表明,对于谐波次数νQ的高次磁势,不宜再用比磁导的概念而应直接采用场的办法来计算气隙磁场.最后,本文对正弦磁势下的气隙系数作了进一步的讨论.     

异步电动机气隙不均匀引起的电磁力波的计算

导出了由于偏心出现的气隙磁导二次谐波系数(λ     

凸极同步电机非均匀气隙磁导的计算

在简要介绍了等效磁路法模型进行电机仿真分析的方法后,对气隙非均匀的凸极同步电机的定子齿与转子齿之间的气隙磁导计算方法进行了分析与研究,推导出了在任意转子机械角位移下的气隙磁导及其对角位移的一阶和二阶导数的计算方法。文中给出了一个计算实例。     

永磁直线同步电机空载反电动势和推力的解析计算

针对目前永磁直线同步电机(PMLSM)磁场解析模型的复杂性,为了提高解析模型的计算效率,采用改进的二维气隙相对磁导函数,以计算考虑齿槽效应时电机的空载反电动势和推力.首先建立无槽PMLSM解析模型,提出改进的二维气隙相对磁导函数以解决切向气隙相对磁导分布,根据有槽PMLSM解析模型计算出电机开槽时的气隙磁通密度法向和切...     

永磁无刷直流电机空载气隙磁场和绕组反电势的解析计算

该文利用许－克变换构造了考虑齿槽效应的气隙相对比磁导函数，该气隙相对比磁导函数反映了齿槽效应对气隙磁场分布的影响，且这种影响的程度随气隙中的径向位置而变化，在忽略铁心饱和的情况下，结合偏微分方程的解析算法，提出了一种考虑齿槽效应的永磁无刷直流电机空载气隙磁场分布和相绕相反电动势的解析计算方法，计算结果与二维有限元计算结果对比，其计算波形和大小吻合很好，证明此方法是正确的、可靠的、为永磁无刷直流电机优化设计和性能分析提供了基本分析手段。     

汽车发电机变化气隙磁导模型的建立

推导了汽车发电机中气隙磁导的计算模型。考虑汽车发电机高速运行中承受旋转离心力和电磁激振力而导致转子爪极形变,建立了汽车发电机的变化气隙磁导模型。建立汽车发电机的Maxwell 3D计算模型,得出汽车发电机额定转速下的爪极形变前后的磁场分布和气隙比磁导基波分布,并对其气隙磁密的各次谐波进行了分析比较,证明了建立变化气隙磁导模型的合理性,为汽车发电机中气隙磁场分析和振动噪声分析进行精确的设计计算提供指导意义。     

轴向充磁圆筒型永磁直线同步电机气隙磁场解析计算

介绍了一种基于许-克变换法的轴向充磁结构圆筒型永磁直线同步电机(TPMLSM)气隙磁场解析计算方法。首先采用许-克变换法计算出无齿槽时电机的气隙磁场;然后利用许-克变换法求取初级铁心开槽时的气隙相对比磁导函数,分析铁心开槽对气隙磁场的影响;最后通过无齿槽时的气隙磁场与有齿槽时的气隙磁场相对比磁导函数得到有齿槽时电机的气隙磁场分布。同时给出了该种充磁结构TPMLSM气隙磁场解析计算表达式,并以1台36/12极槽配合轴向充磁TPMLSM样机进行试验。试验结果证明空载气隙磁场的有限元分析值与解析值较吻合,空载电动势(EMF)计算值、试验测试值、有限元分析值一致。     

磁楔气隙系数计算

气隙系数是描写有效气隙变化和磁导谐波特征的最重要参数。本文主要研究磁楔气隙系数的计算。     

基于软测量的电磁系统气隙动态参数的研究

电磁系统气隙动态参数（以气隙磁导为主）的计算精确度,在很大程度上影响着整体动态过程的计算结果,但气隙磁导无法用传感器进行直接测量。本文针对这一矛盾,将软测量技术引入到电磁系统气隙动态参数的研究中,实现了气隙磁导的软测量,为提出以精确测试为基础的新电磁电器动态设计方法奠定基础。     

定子开槽永磁同步电机气隙比磁导解析计算

采用镜像和保角变换相结合的方法计算定子开槽永磁同步电机的气隙比磁导。以光滑转子铁磁表面为镜面,将定子开槽永磁同步电机气隙原像及其镜像作为解析模型,经过多次保角变换得到气隙比磁导解析公式。解析模型考虑了齿槽之间的影响、定子开槽对气隙磁场径向分量和切向分量的影响,解析公式可用于定子开槽永磁同步电机的励磁磁场、电枢反应磁场、电磁力和齿槽转矩。在解析模型的基础上,对某定子开槽永磁同步电机单个齿槽指定路径上和气隙区域内气隙比磁导进行求解,与有限元结果相比较,表明了所提解析方法的准确性。     

永磁游标直线电机磁场解析计算

永磁游标直线电机(linear permanent magnet vernier motor,LPMVM)依靠磁场调制原理工作,其电枢开槽引起气隙磁导变化,为考虑齿槽效应的影响,将其气隙磁场等效为无槽气隙磁场与有槽时气隙相对磁导函数共同作用结果。用气隙磁导波法分析其基本工作机理,给出结构关系式。用分层模型法建立无槽LPMVM求解场域矢量磁位解析模型,推导出各区域磁场解析表达式。结合气隙相对磁导函数建立考虑齿槽效应时的LPMVM磁场解析模型,计算出考虑齿槽效应时气隙磁密分布曲线。解析解与有限元解结果表明:无槽时气隙磁密在切向分量和法向分量计算准确,考虑齿槽效应后基于气隙相对磁导函数的磁场解析模型适用于求解气隙磁密法向分量,且主要谐波磁场与永磁体极对数和电枢绕组极对数有关。     

Use of permeance-based air-gap flux density analysis in the development of a synchronous generator model

The magnetic flux inside a synchronous generator is regarded as a characteristic that dominates a generator operation. This paper develops a simple model of a synchronous generator by which it is possible to easily estimate an air-gap flux as well as electrical characteristics. The air-gap flux density can be related to a permeance and a magnetomotive force (mmf) along its magnetic path by the Ampere's laws. These relations are used in this paper. We estimate the distribution of the permeance along the air-gap and the mmf profiles of the stator and the rotor of a 6 kVA scaled-down tested synchronous generator. From these estimated profiles, the relations among the air-gap flux, field current, and armature current are represented by a linear equation system. Consequently, the static electrical and magnetic characteristics of a synchronous generator can be estimated by giving only field exciting voltage and load impedance. The distributions of the air-gap flux density and waveforms of the field and armature currents are simulated for various unbalanced-load conditions. The simulated results well agree with experimental ones not only for fundamental components but also for higher harmonic components. Therefore, our method, based on the permeance profile, is available to calculate the static characteristics of synchronous generators.     

利用混合式步进电动机谐波反电动势实现转子位置检测

利用气隙比磁导法建立了混合式步进电动机的磁推导出反电动势的表达式。在此基础上提出了一种谐波反电劝势信号实现电机转子位置检测的新方法,设计了与电机一体化的新型益传感器,实验结果验证了理论分析的正确性。这种新型位置传感器为进一步实现步进电动机闭环控制奠定了基础。     

Determination of effective air-gap length of synchronous reluctance motors (SynchRel) from experimental data

The usage of synchronous reluctance motors (synchRel) has been gaining importance in many industry applications mainly because of their many advantages over other motors. The performance of a synchRel is greatly dependent on its effective air-gap lengths along the d and q axes. Hence, in this paper, an attempt has been made to obtain the effective air-gap lengths of the machine from the experimental values of the d and q axes reactances and by considering the higher permeance and winding space harmonics. To determine the air gaps, these reactances are compared with their corresponding expressions involving the coefficients of magnetizing and mutual inductances of the stator windings, obtained by using the winding function approach (WFA). Using these air-gap values, a more realistic model of the machine is obtained. A comparative study has been carried out with different permeance and winding space harmonics. The computed q-axis air-gap length seems to be much more sensitive to the operating point and the leakage inductance, compared to the computed d-axis air-gap length. Experimental values near the no-load condition have been considered to minimize flux barrier effects, as WFA cannot simulate these effects without changing the length of the pole arc. The effective air gaps of another salient-pole synchronous machine with damper bars have also been determined by considering the higher permeance and winding space harmonics, when run as a synchRel (without field excitation). This machine did not have flux barriers, and, hence, the results seem to be more accurate. Finally, the performance of the simulated synchRel has been compared with the experimental results.     

变极凸极同步电机气隙磁导谐波磁场及其在定子并联支路中引起环流的分析

通过对变极凸极同步电机气隙磁导谐波磁场及其定子各支路绕组的分析，从理论上证明了该类类电机气隙磁场中存在很强的分数次谐波分量。这种谐波将会在有并联支路的定子绕组中产生环流。     

电励磁爪极发电机气隙磁场与径向电磁力的解析计算模型

爪极发电机因其特殊的转子结构导致磁场空间分布复杂,通常需要建立三维有限元模型对其进行计算分析。而三维有限元方法计算费时,且不便于分析发电机结构及电磁参数对磁场和电磁力的影响,因此提出一种气隙磁场与电磁力的解析计算模型。首先,考虑定子相电流谐波对气隙磁动势的影响及爪极倒角和定子开槽对气隙磁导的影响,建立气隙磁场的解析模型;在此基础之上,利用麦克斯韦应力张量法建立径向电磁力的解析模型,并依据解析模型对爪极发电机电磁噪声影响最大的36阶电磁力来源进行分析。所建解析模型的计算结果与有限元计算结果吻合,有限元结果得到了样机试验验证,从而说明了解析模型的准确性。     

Effect of the stator slot opening on the electromagnetic vibration in a squirrel-cage induction motor

Field harmonics produce a radial electromagnetic force in a squirrel-cage induction motor with a particular number of rotor slots corresponding to the number of poles. The radial force causes vibration and acoustic noise. In this paper, a simplified equation for the radial force at no-load is introduced, and the relation between the width of the stator slot opening and the radial force is discussed quantitatively. The field harmonic component produced by the interaction between the fundamental magnetomotive force due to the stator current and the pulsation of air-gap permeance dominates for the radial force. Furthermore, the vibration of the stator core due to the radial force is calculated under a simple assumption. The calculated results are verified by experiments.     

次级对直线感应电动机性能的影响

为了研究直线感应电动机次级材料和厚度对电机性能和气隙磁密的影响,采用有限元方法,建立了电机的电磁场计算模型,研究电机的起动及运行过程.在数值计算的基础上得到电机的磁场分布,对气隙磁密进行谐波分析,得到了随着次级板厚度减小,气隙磁场增强,谐波含量较小的变化规律,并在电磁气隙不变的情况下,分析次级厚度及材料变化时对电机推力的影响,即随着次级板厚度及次级电导率减小,电机起动推力减小.实验结果验证了该电机计算模型的正确性.     

基于二维解析法的光滑表面实心转子感应电机附加损耗的研究

在普通异步电机中，由于附加损耗数值较小，通常按总功率的5%粗略估算。在实心转子感应电机中，附加损耗中的表面涡流损耗数值远大于普通笼型感应电机，不但成为实心转子感应电机附加损耗的主要部分，而且是造成这种电机效率低、电机过热的重要原因，限制了该类电机的应用和发展。文中运用二维解析法及坡印亭定理对实心转子的表面涡流损耗进行了计算，与试验结果比较显示，理论计算在小转差范围(0~0.2)内取得了与实际较为一致的结果，并分析了大转差下产生偏差的原因。在小转差(s=0.107)运行状态，对定子槽口宽度变化和气隙长度变化对转子表面涡流损耗影响进行仿真计算。结果表明，改变槽口宽度对该种电机转子的表面涡流损耗影响不明显，随着气隙长度的增加，附加损耗曲线分为快速下降，缓慢下降两段。在曲线缓慢下降段综合考虑选取气隙长度是合适的。