采用斜槽降低三相异步电动机电磁噪声

电磁噪声是中小型三相异步电动机设计过程中重点关注的问题之一。现根据电磁噪声产生的原因,提出了采用各种不同的处理方式来实现电动机的斜槽,达到了削弱或消除电磁噪声,从而提高了电动机的质量,为同类型电磁噪声提供解决措施。     

降低电动机的噪声

目前已经用电子计算机系统地研究电动机的电磁噪声问题。随着电动机功率的增加,在中大型高速电动机中.气动噪声大于电磁噪声,对于一般工业用电动机,必须考虑电磁噪声和气动噪声,采取措施予以降低。电磁噪声受定、转子槽配合、绕组设计、导磁率和类似参数的影响。在发展电动机系列时,采用电子计算机最佳选取上述参数。有时为了统筹考虑其他电气数据,设计的电动机并不总是噪声特     

鼠笼异步电动机电磁噪声的仿真分析

依据鼠笼异步电动机电磁噪声产生的机理,该文从电磁力、机械振动和声辐射特性三个方面进行仿真得到电磁噪声。利用电压作为输入的场路耦合时步有限元模型计算电流、磁场和径向电磁力,并分析径向电磁力的谐波;基于机械有限元模型研究定子振动模态以及在电磁力激励下的振动响应;利用声学边界元模型计算电动机的辐射声场。试验测量结果验证了电磁噪声仿真计算的有效性。基于该文电磁噪声仿真方法可在设计阶段对电磁噪声进行定量预估,有助于低噪声电动机的设计研发。     

异步电动机电磁噪声的电磁力计算方法研究

介绍了异步电动机电磁噪声产生的原因,并详细论述了引起电磁噪声的电磁力的解析计算方法-磁势磁导法。以一台异步电动机为例,采用磁势-磁导法对电磁力计算过程进行详细分析。     

笼型三相异步电动机噪声故障简析

讲述了笼型三相异步电动机的噪声测量方法和标准限值。对电机空载和负载运行时的噪声故障进行了分析,重点阐述笼型三相异步电动机空载运行时,机械和电磁两方面的噪声故障隐患表现和修理预防措施。     

降低三相异步电动机电磁噪声

本由异步电动机电磁噪声产生的原因入手，从设计的角度出发，详细介绍了削弱异步电动机电磁噪声的几种方法，并结合生产实践加以说明。     

永磁同步电动机电磁振动噪声的研究

电机的噪声大小是永磁同步电动机的重要性能之一,降低电机本身的电磁噪声是降低噪声的重要途径。通过解析法推导了负载条件下永磁电动机电磁激振力的解析表达式,并对激振力进行了分析,结果表明:永磁电动机的极对数、定子槽数和控制方式等是影响电磁振动噪声的主要因素。最后利用有限元法对2极18槽永磁电动机进行了仿真,结果验证了理论分析的正确性。     

降低笼型三相异步电动机电磁噪声的研究

总结、论述了在降低笼型三相异步电动机电磁噪声的研究过程中采取的措施,提出了选择槽配合消除一、二、三阶电磁力波,同时辅以选择斜槽距离消除同步附加转矩的影响,把二者结合起来作为降低笼型三相异步电动机电磁振动和噪声的综合方法的观点。给出了有关计算结果和试验结果。     

电动机噪声理论和控制技术的进展

首先对电动机噪声理论及控制技术国内外的研究概况作了简要的回顾 ,介绍了这方面新的研究成果 ,然后介绍新的二维电磁噪声理论 ,这是对传统的电磁噪声理论的重要发展。最后针对我国电动机 (基本系列 )在噪声方面存在的突出问题 ,提出了解决问题的途径。     

车用永磁同步电动机电磁噪声的仿真分析

基于Workbench仿真平台,对一款48槽8极的车用永磁同步电动机的电磁噪声进行仿真分析.利用有限元软件得出该电动机的径向电磁力波和定子的固有模态,通过对径向电磁力波进行时空二维傅立叶分解,得出其空间阶次以及频率特征.最后通过分析仿真结果,得出该电动机存在高频电磁噪声的原因.对后续抑制电磁噪声有重要意义.     

Causes and characteristics of the electromagnetic vibration of a squirrel cage induction motor under load

Three-phase squirrel cage induction motors (IM) have been used in all types of industry, because of their robustness and simplicity of structure, low cost, and ease of maintenance. Due to the resultant air gap flux wave, an IM produces electromagnetic vibration and noise more or less regardless of the slot combination. Recently, reduction of electromagnetic vibration and noise has become important from the standpoint of environmental improvement. Vibration caused by an IM at no-load has been studied for many years and its basic factors have been analyzed. However, electromagnetic vibration under load has not been analyzed sufficiently. Since vibration under load conditions is affected by load and installation, analysis of this vibration is a rather difficult task. But study of the electromagnetic vibration of the motor itself under load is basically the most important item. This paper clarifies, theoretically and experimentally, the causes and characteristics of the electromagnetic vibration of an IM under load conditions. First, general equations are derived for the dominant electromagnetic force waves that produce electromagnetic vibration. Causes and vibration modes are clearly classified and a theoretical analysis provides a basic concept for electromagnetic vibrations. Second, electromagnetic vibrations for various loads are measured taking the effect of natural frequency of the motor into consideration. The measured data are classified and analyzed in detail, based on the proposed theory. © Scripta Technica, Inc. Electr Eng Jpn, 120(4): 81–89, 1997     

基于粒子群算法的核屏蔽感应电机多目标优化设计

屏蔽感应电机是核反应堆冷却回路的动力源,提高该电机的效率和降低电磁噪声具有重要的意义。将有限元法和磁路法相结合,设计了1台20 kW核屏蔽感应电机。利用有限元软件对其进行额定工况运行状态下噪声和损耗仿真分析,确定影响电机效率和电磁噪声的主要参数;选取影响电机效率和噪声的主要参数为优化变量,电机电磁噪声和效率为优化目标,输出功率为约束条件;采用正交试验表获得样本空间;通过响应面法建立优化目标及约束条件的优化模型,最后利用粒子群算法对优化模型进行求解。有限元仿真结果表明:优化后电机效率提高了2.6%,电磁噪声降低了5.2 dB。     

整数槽同步电机低振动噪声定子结构设计

针对电机电磁振动噪声问题,依据电磁振动噪声的基础理论,采用电磁和结构弱耦合的有限元仿真方法,以1台12极72槽车用永磁同步牵引电机为例,分析在不同长宽比、槽口宽度以及结构综合变化的条件下,径向电磁力密度的情况;同时对整个电机进行电磁-结构耦合场分析,研究结构振动位移在不同定子长宽比、槽口宽度以及结构综合变化时的响应情况。综合比较分析两种仿真结果,给出了电磁振动噪声关于定子结构长宽比和槽口宽度的变化规律。最后在额定负载工况下对实物样机进行振动检测和频谱分析,与仿真数值进行对比分析,以验证仿真试验的准确性。     

配电网柔性互联系统多模式运行及其调控策略

针对基于柔性多状态开关的配电网柔性互联系统存在的多模式运行与切换、馈线负荷不均衡和主变重载问题,提出了基于虚拟同步机技术的负荷均衡调控策略和主变重载自动调控策略。首先,根据馈线与主变的负载状态,将系统进行运行模式划分;然后,针对系统的不同运行模式深入分析对应模式下的功率传输平衡关系和内在切换逻辑,应用调控策略得到多模式运行下的柔性多状态开关有功功率调控指令,实现了系统多模式稳定运行和自由切换、馈线负荷均衡以及主变重载自动调控,且无需进行控制策略切换。     

打开高低压电磁环网运行研究

高低压电磁环网对电网运行的最大危害在于,当环网中高压线路发生故障掉闸,大量的潮流将转移至低压网络,导致线路过负荷、系统电压降低,甚至发生电压崩溃和发电机功角失稳。随着网架结构的加强,应逐渐解开电网中运行的高低压电磁环网。结合一个典型的电磁环网,从电网潮流分布、电压水平、暂态稳定水平、断面输送能力、供电可靠性及供电能力等方面分析其解环可行性,研究其解环方案,并对解环后系统存在的若干问题进行探讨,提出解决对策。     

Causes and characteristics of the electromagnetic vibration of a capacitor motor under load

Capacitor motors (CRMs) are widely used to drive industrial equipment and home electric appliances. Recently, reduction of the vibration and noise of CRMs has become increasingly important from the standpoint of environmental improvement. However, electromagnetic vibration of CRMs under load has not been sufficiently analyzed. The present paper theoretically and experimentally discusses the causes and characteristics of CRM electromagnetic vibration under load. The primary conclusions are as follows:

• (1) The general formula for the dominant electromagnetic vibration caused by electromagnetic force waves was derived, including the influences not only of a backward magnetic field but also of magnetic saturation.
• (2) The dominant electromagnetic vibration of CRMs is theoretically attributed to three types of electromagnetic force waves. Two types of electromagnetic force wave are generated by the interaction of two forward magnetic fluxes, such as those of a three‐phase squirrel‐cage induction motor, and the other type of electromagnetic force wave is generated under the influence of a backward magnetic flux.
• (3) The characteristics of the dominant electromagnetic vibration depending on the load and the running capacitance are subdivided theoretically and experimentally into three types based on the characteristics of the electromagnetic force wave and the equivalent circuit current.
• (4) The influences of magnetic saturation in dominant electromagnetic vibration have been verified experimentally and their causes have been clarified theoretically in relation to electromagnetic force waves. © 2005 Wiley Periodicals, Inc. Electr Eng Jpn, 153(4): 68–76, 2005; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20129

     

特高压半波长交流输电线路稳态特性研究

基于特高压半波长交流输电系统的正弦稳态解析解,分析了系统接感性负载和容性负载2种情况下,负载特性、功率因数对稳态运行特性的影响.结果表明:在不出现严重过载的正常工况下,半波长交流输电系统的线路过电压水平较低,线路损耗和电晕损耗较低,送端和受端的电压和电流的有效值差很小,相位基本反相;在过载情况下,线路中间段出现过电压现象;负载功率因数越高,线路的电压和电流越稳定.     

高速异步电主轴电机的电磁噪声分析

采用有限元法分析了高速异步电主轴电机定子结构的动力学特性(振型、固有频率),分别采用解析法和有限元法分析了电机在额定转速60 000 r/min下空载和负载的电磁力波,利用傅里叶变换对径向气隙磁密和径向电磁力波进行了谐波分析,得到了不同阶次不同频率下的谐波幅值。还将得到的电磁力波加载到电机定子相应节点处,对高速异步电主轴电机进行了电磁振动和声场分析,并计算出电机在空载和负载情况下产生的电磁噪声。     

风力发电同时率与控制风电出力的研究

张家口地区风力发电不断发展,负荷远不能平衡风电出力.风电发电潮流反送到变压嚣,导致变压器满载甚至超载,给电网设备安全及调度运行带来了很多的困难.通过对典型月份各风场发电同时率的分析,进而研究地区负荷情况、风电发电出力与限制风电出力之间的关系,得出具体控制出力的结论,从而为调度运行人员提供切实可行的理论依据.     

Noise Test on Rotating Electrical Motors Under Load

ABSTRACT

The noise of the rotating electrical motor can be strongly influenced by the change in the loading conditions. In extreme cases a noise component of electromagnetic origin may increase by 36 dB or decrease by 24 dB upon loading.Protection of a human being from the noise depends on the noise characteristics of the el. machine under operating conditions. The standards relevant to the noise qualification measurements permit the use of the sound power level determined under no–load conditions, if the noise of the machine does not vary with the change in the load. This is a concession that is made because it is difficult to separate the noise level of the loading machine from the noise of the electric motor being investigated. This paper presents several methods, and their analyses, where the sound power level emitted by a loaded electrical motor can be determined experimentally in an industrial environment.Wide ranging experimental work has been made in this field, which will be be presented at the end of the paper.