Operation of a dual excitation multiphase electrostatic drive by amplitude‐modulated ac voltage

Dual Excitation Multiphase Electrostatic Drive (DEMED) is a synchronous motor that is driven by electrostatic force. Because of its light weight, thinness, and large power per weight ratio, it has promise as a small‐size, high‐power motor in the future. Of the three types of driving method that had been formerly developed for the motor, the single frequency method, which drives the motor by applying a three‐phase ac voltage to the electrodes of the motor, is the most useful since it needs the least number of phases of power supply. However, this method has problems with operation at very low speed such as 10 μm/s. In order to solve such problems, this paper proposes a novel add‐on operation method. In the new method, called modulation drive, the excitation voltage to each phase of the electrodes is amplitude‐modulated by a carrier signal with higher frequency before being applied to the electrodes. In tests regarding the single frequency method, the modulation drive successfully drove a motor with typical power operational amplifiers that were boosted by transformers with ferrite cores, and eliminated the force degradation at low drive speed. Additionally, the force generation of modulation was analyzed, and the results agreed very well with the experimental results. © 2000 Scripta Technica, Electr Eng Jpn, 131(4): 78–84, 2000     

Dual excitation electrostatic stepping motor

Electrostatic motors have been believed to be weaker than electromagnetic motors which are typically used for mechatronic devices. However, electrostatic motors are preferable to electromagnetic ones for micromechanical applications since their force per volume ratios increase as their dimensions are reduced. It follows that a large output should be obtained if a large number of such small motors with high force per volume ratios are linked and their outputs are aggregated. This paper proposes an electrostatic drive technology which is applicable to such a large-output motor. The element motor, called the dual excitation electrostatic stepping motor, consists of a pair of plastic films, slider and stator. Both films have parallelly located electrodes embedded in them, and the slider moves along the surface of the stator when defined rectangular pulse voltages are applied to the electrodes both in the slider and the stator. The force generation characteristic of the electrostatic motor is calculated by the surface charge method. A prototype fabricated using flexible print board technology weighs 7 g and generates a thrust force of 1.9 N at an excitation of ± 1000 V. © 1997 Scripta Technica, Inc. Electr Eng Jpn, 119(3): 94–103 1997     

抑制开关磁阻电机振动的结构设计研究

开关磁阻电机(SRM)应用于众多领域,但是本身的结构使其比其他传统电机有更大的振动和噪声,因此抑制SRM振动仍是研究的热门领域。为了抑制电机的振动,设计了一种新型的电机结构,即在转子两侧开孔,并在此基础上对定子齿顶开槽。以一台7.5 kW、1 500 r/min、12/8极SRM为例,通过有限元分析仿真,对新型电机结构进行参数化计算,并得到最优结构。在保证平均转矩基本保持不变的情况下,减小了转矩脉动以及径向力。与原始电机相比,转矩脉动系数下降了16.01%,径向力峰值下降了19.96%。因此,证明了该方法对SRM振动抑制有较好的效果,对后续SRM设计及控制具有一定的借鉴意义。     

矩形与面包形磁钢永磁同步电机噪声对比分析

为了对比分析矩形磁钢和面包形磁钢永磁同步电机运行时产生的0阶振动噪声,从理论上对电机的径向电磁力波进行推导,对力波的的磁密来源进行了分析,讨论了两种不同磁钢形状的永磁同步电机的0阶振动噪声。基于Workbench仿真平台,对这两种不同磁钢形状的36槽24极永磁同步电机进行仿真分析,得到两种电机的0阶6倍频力波的组成和0阶径向电磁力波的傅里叶分析结果;对电机定子的结构分别进行有限元建模和解析计算,得出电机结构的固有模态;通过解析计算的方法,得到电机定子表面的0阶电磁力振动位移频谱图;最后,通过计算电机的声辐射效率,对电机外部声场进行快速建模,计算出电机0阶电磁力声功率级频谱图。研究表明:面包形磁钢永磁同步电机的振动噪声要远小于矩形磁钢永磁同步电机的振动噪声。     

转子不同方式分段斜极对永磁同步电机噪声的影响

电磁振动噪声水平是衡量电动汽车舒适性的综合指标。径向电磁力是电磁振动噪声的主要激振源。对电动汽车驱动用永磁同步电机(PMSM)的径向电磁力进行分析,对径向电磁力时空分离得到的三维频谱图提取出对电磁噪声影响较大的时空阶次及力密度,再运用有限元法对转子不同方式分段斜极的PMSM进行振动噪声仿真,通过结果对比找到最优的转子分段斜极方式。     

新能源汽车用永磁辅助同步磁阻电机噪声及续航优化研究

永磁辅助同步磁阻电机具有高转矩/功率密度、高效率区间、高转速、低反电动势、低成本等优势,在新能源领域特别是乘用车驱动系统中得到越来越广泛的应用。但该类电机凸极率大、波形畸变大、转矩脉动大,易导致电机振动噪声及效率低下,进而导致整车振动噪声及续航不足等问题。通过增加转子隔磁孔,改变磁路走向的方式,降低了电机全转速段转矩脉动和对应负载气隙感应电动势波形总谐波畸变(THD)。对电机优化前后径向电磁力及谐响应进行仿真对比分析,并通过试验验证了该优化方法的有效性。     

气隙偏心对车用永磁同步电机噪声特性的影响分析

新能源汽车领域竞争的加剧,对驱动电机噪声、振动与声振粗糙度(NVH)性能提出了更高的要求。其中气隙偏心可能导致车用电机出现振动和噪声问题。本文以一台额定功率35 kW的车用永磁同步电机为研究对象,采用解析和有限元仿真相结合的方法分别分析转子动偏心和转子静偏心对车用电机电磁力特性的影响。并建立了电机结构的有限元模态仿真模型,准确分析车用电机的工作模态。在声学仿真分析基础之上,分析了不同程度的动偏心率和静偏心率对汽车电机两个关键工作点电磁噪声频谱特性的影响。最后,通过半消音室内的电机噪声测试试验验证理论分析的正确性。     

不对称磁障对IPMSM电磁振动噪声的影响分析

针对目前一些采用不对称磁障法降低内置式永磁同步电机(IPMSM)转矩脉动的研究并未细致分析其对电机电磁振动噪声产生何种影响的问题,以一台37 kW IPMSM为研究对象,建立了原始电机和具有不对称磁障结构电机的电磁场有限元模型与振动噪声耦合模型,对比分析了不对称磁障结构对电机振动噪声的影响。从理论上分析了永磁电机径向电磁力波的阶次、频率特征,并利用有限元法与二维傅里叶分解法对得到的气隙处径向电磁力波进行分解。建立定子结构有限元模型,对其进行模态分析。在仿真平台搭建振动噪声耦合模型,仿真得到电机定子振动响应与电磁噪声。结果表明,采用不对称磁障的设计方法虽然能降低电机的转矩脉动并且不会牺牲电机输出转矩,但会产生其他倍频的电磁力,增加相对应频率点的振动响应,增大电机的振动噪声,设计时需综合考虑。     

Development of a controller for a high‐power electrostatic motor

Development of a controller for high‐power electrostatic motors is described in this paper. The controller includes stereo audio amplifiers, small transformers, and an operation signal generator. The signal generator generates controlled operation signals for dual‐frequency operation methods so that a motor can generate commanded thrust force. By using frequencies of several kilohertz for operation signals and by using resonance between an electrostatic motor and transformers, it became possible to use commercially available audio amplifiers as power sources and to use small transformers, resulting in an inexpensive and compact controller. This paper mainly discusses the design of the signal generator and the transformers. Some experimental results are also shown. © 2000 Scripta Technica, Electr Eng Jpn, 133(4): 91–99, 2000     

双凸极永磁电动机转矩脉动分析

双凸极永磁电动机是一种新型高性能宽调速电动机 ,正日益受到重视 ,但该电动机的输出转矩中含有较明显的脉动分量。本文分析了转矩脉动产生的原因 ,导出了转矩脉动率的函数表达式 ,在此基础上提出了减小转矩脉动率的开关角调节法和转子斜槽法 ,仿真分析表明了二者的正确性和有效性     

Effect of stator chording and rotor skewing on performance ofreluctance synchronous machine

Low torque ripple in electrical machines is generally required to reduce acoustic noise and mechanical resonance vibration. To design for low torque ripple, however, affects the average torque and the power rating of the machine. In this paper, the effect of stator winding chording and rotor skewing on the average torque, power factor, and torque ripple of the normal laminated, internal flux barrier rotor reluctance synchronous machine is investigated. The two-dimensional finite-element time-step method together with the basic machine equations are used in the analysis. It is shown that to design, in general, for low torque ripple and minimal effect on torque rating of the reluctance synchronous machine, full-pitch stator windings must be used, the rotor must be skewed by a stator slot pitch, and a low number of stator slots must be avoided     

小型无刷直流电动机振动与噪声的研究

该文首先综述了无刷直流电动机的优点,比较了少槽小型无刷直流电动机的特点。给出了电动机相电势矢量图及绕组构成,分析了电动机径向不平衡电磁力产生的原因。然后对9槽无刷直流电动机电磁转矩进行了计算,比较了不同极数下电动机的转矩特性。利用磁场解析定量研究了具体电动机在矩形波驱动电流换相时的径向不平衡电磁力,比较了在产生相同电磁转矩情况下电机径向不平衡电磁力的相对大小关系,分析了对电动机振动及噪声的影响。最后利用超小型加速度传感器对样机径向振动进行了测试,在无音实验室对样机的噪声进行了测试。实验证明了计算分析结论的正确性,为小型无刷直流电动机的设计提供了参考。     

径向斜槽转子潜水电机电磁噪声优化

相比于一般电机,大型潜水感应电机目前存在电磁噪声过大的问题。采用径向斜槽结构可以削弱大型潜水电机的电磁噪声,但仍存在部分不足。基于径向斜槽结构,通过调整径向斜槽扭斜距离进一步削弱电磁噪声,并提高电机其他性能。利用多物理场耦合有限元仿真分析对比各方案的电磁噪声,验证了上述方法的正确性。     

一种磁悬浮永磁直线电动机的电磁力特性

为消除直线电机数控机床进给系统的摩擦阻力,提出一种自身产生磁悬浮力的磁悬浮永磁直线同步电动机.从描述磁介质的分子环流假设出发,用毕奥-萨伐尔定理导出永磁体外部空间磁场分布的解析表达式,并基于由磁荷法和虚位移法给出的永磁体磁力数值积分公式,椎导出电机悬浮力波动的解析模型,说明斜极对电机悬浮力的影响.利用Maxwell 3D软件建立三维有限元瞬态分析模型,结果证明该磁悬浮永磁直线电动机自身可以产生独立并可控的推力和悬浮力.进一步建立斜极结构下电动机的三维有限元模型,分析结果表明采用斜极结构可以有效的减小电机推力和悬浮力的波动.     

Reduction of Vibration in Concentrated Winding Permanent Magnet Synchronous Motor by Means of Skew Effects of Rotor

Global warming and the problem of successfully incorporating environmental safeguards are promoting the need for a more power‐efficient motor. Therefore, as a driving source, permanent magnet synchronous motors (PMSMs) with concentrated winding are widely used in a variety of fields. However, a PMSM with a concentrated winding generates more vibration than one with a distributed winding because of the radial electromagnetic force. This paper describes the effect of a new skewed rotor on the characteristics of a concentrated winding PMSM. We investigated this effect by three‐dimensional finite element method (3D FEM) analysis and measurement. We also demonstrate that the proposed rotor is effective in reducing the radial electromagnetic force without decreasing motor efficiency. © 2014 Wiley Periodicals, Inc. Electr Eng Jpn, 187(2): 33–43, 2014; Published online in Wiley Online Library ( wileyonlinelibrary.com ). DOI 10.1002/eej.22400     

内置式永磁同步电机不同转子拓扑结构对电机性能的影响分析

为了研究不同转子拓扑结构对8极48槽内置式永磁同步电机(IPMSM)的电磁性能和噪声性能的影响,分别建立了单层无隔磁桥、单层有隔磁桥、双层无隔磁桥以及双层有隔磁桥转子拓扑结构的内置式永磁同步电机的有限元模型。除转子拓扑结构以外,四种电机的定子拓扑结构、永磁体使用量等其它条件完全相同。首先,对电机电磁性能和噪声性能进行相关的理论分析。其次,建立四种电机的有限元模型,对四种电机的凸极率、输出转矩、转矩脉动以及空载反电势谐波畸变率等电磁性能进行比较分析,并对四种电机进行模态分析。最后,比较了四种电机的振动响应和噪声特性。结果表明,双层有隔磁桥转子结构的内置式永磁同步电机电磁性能最好,并且其噪声削弱效果也最好。     

转子分段斜极永磁同步电机电磁振动噪声研究

基近年来永磁同步电机(PMSM)以其高效、节能的优点被广泛应用于电动汽车行业。然而电机的高频噪声已成为限制PMSM发展的关键因素。鉴于此,建立了一种能够进行电磁噪声预测的多物理场仿真模型,验证了所建立的仿真模型在预测和评估电磁噪声方面的有效性。另外,提出了一种可影响电磁噪声的转子分段斜极模型,并详细研究了斜极角对电磁噪声的影响。通过研究对电磁噪声影响较大的低阶径向磁力的光谱特性,比较分析了有无转子分段斜极的永磁同步电动机的电磁噪声特性分布。实验结果表明:在不同的斜极角下径向力密度的光谱是不同的;在频率范围内有转子分段斜极电机的SPL高于无转子分段斜极电机的SPL;所构建的基于多物理场的仿真模型能够很好地预测电磁噪声。     

Comparison of vibration sources between symmetric and asymmetricHDD spindle motors with rotor eccentricity

The permanent-magnet motor is often the most important element in hard disk drive (HDD) spindles and is also a frequent source of vibration and acoustic noise. Eccentricity between the stator and rotor is inevitably introduced during the manufacturing process, and includes mass unbalance, shaft bow and bearing tolerances. This paper analytically discusses the effects of rotor eccentricity on motor performance for symmetric and asymmetric motors, such as local traction, unbalanced force, cogging torque, back electromotive force (EMF), phase current and torque ripple. An asymmetric motor, mostly chosen to reduce the cogging torque, shows a worse effect on cogging torque and unbalanced force when the eccentricity exists. It also adversely affects the flux linkage and introduces variation of the phase back EMF depending on winding and rotating eccentricity, thus yielding increased mutual torque ripple     

永磁同步电机转矩脉动和振动噪声抑制

抑制转矩脉动和振动噪声是设计永磁同步电机的难点之一。通过对永磁同步电机齿槽转矩形成机理进行分析,考虑极弧系数和大小极磁极结构对齿槽转矩的影响。基于等效面电流法对永磁同步电机的气隙磁场进行建模。采用粒子群算法优化了永磁同步电机的极弧系数,利用大小磁极结构配置方式,降低了气隙电磁力谐波对转矩脉动幅值影响较大的阶次,从而实现抑制电机齿槽转矩的目标。将永磁体优化前后的转矩脉动和噪声幅值进行对比表明,该方法可有效地降低永磁同步电机的转矩脉动和振动噪声。     

高压高速大功率无火花型电动机设计

介绍了高压高速大功率无火花型电动机设计(以下简称:高压无火花电机)需要考虑的主要问题,主要包括电机火花的控制,功率的提升,自润滑滑动轴承的选择,振动和噪声的抑制,通过设计计算结果与实测值对比,进一步优化了电机的各项性能指标。