小尺寸双排绕组感应同步器输出电动势的谐波抑制

感应同步器作为一种电磁式位置传感器,具有精度高、安装简单等优点,广泛应用于各类高性能伺服系统。传统的感应同步器采用定子分段式结构,绕组制作工艺的严苛要求制约了感应同步器向小型化高精度的发展。该文提出一种新型的定子双排绕组结构感应同步器,可以有效地抑制加工不善带来的导体偏差。对双排绕组感应同步器的测角原理进行分析,计算了其输出的偏差电动势,并通过建立有效导体的电流密度模型来提出抑制3、5次谐波的优化策略,进一步提高感应同步器的测角精度,最终根据比电动势一致原理提出双排绕组感应同步器的设计方法并建立3D仿真模型,采用有限元分析与快速傅里叶分解的方法验证了策略的正确性与可行性,并制作样机进行实验。     

利用相敏电压表调试充分发挥产品的最佳精度

作为角度传感元件的分装式旋转变压器和圆感应同步器,其精度要求极高,如何安装调试才能得到最佳精度是生产和使用部门十分关心而又感到棘手的问题。本文通过对有关文献的研究,结合产品的实际测试分析,利用相敏电压表测量互相垂直的四套绕组的感应电势的幅值和相位米判别定、转子电气偏心和不垂直度以及气隙不均匀度的大小和位置,有效而较快地调出了产品的最佳精度,以满足高精度的使用要求。这种方法比用示波器优越,我们已应用在圆感应同步器和分装式多极旋转变压器中,得到了较为满意的结果。     

组装式感应同步器—旋转变压器

旋转型感应同步器是一种新颖的位置检测元件,精确度以角秒计。它是高精度自动控制系统中不可缺少的元件,更适于在数字控制系统中使用。国内现在研制的郁是定、转子分为两个片状的分装式产品。这种结构要达到高精度,必须保证定、转子在安装时其绕组图形的电气中心和电气平面严格地和旋转轴线同心和垂直,甚至要求高达微米级。安装调整时需要一套专用工装和仪器仪表及熟练的调心技巧等等,这些都是用户较难实现的。此外,感应同步器是一种多对极的电机,输出电压是许多个重复的正弦波,因而无法用它构成绝对座标制。这些因素在一定程度上影响到高精度感应同步器的应用。西微所经过几年的研究,已经研制成组装式感应同步器——旋转变压器机组,其中感应同步器的精度达到±2角秒,进入世界先进产品行列。     

多极感应同步器的基本理论

感应同步器是一种新型自动化元件,可以测角,也可以测距,圆盘式的用来测角,条状的用来测距。结构简单、工作可靠、抗干扰能力比较强、测量精度比较高,测角精度可达零点几角秒,测距精度可达微米数量级。本文主要讨论圆型感应同步器,基本原理对条状也是适用的。本文主要研究感应同步器的基本理论问题,从磁场耦合的观点出发推导非磁性介质及场性介质作为基板的感应同步器的传递关系,分析端面感应及电容耦合的影响,和片低角距及宽度误差的影响,讨论安装误差的规律及其调整措施的理论根据。     

感应同步器精度分析

感应同步器是一种精密印制绕组电机,它用于自动跟踪系统、同步随动系统和定位测量技术等方面,作为直线位移或角度数据的精密传送、变换和接收。园感应同步器的精度目前可达0.5～1角秒,是精度最高的控制元件之一。图1为园感应同步器典型结构,在定转子基板上敷设了精密的印制绕组,导片的布线精度仅1～2角秒。转子一般(图1a)为单相连续绕组,定子(图1b)为两相分段绕组,电气原理图如图2。感应同步器两相绕组的输出电压与定转子间的转角成正弦和余     

数字程序控制机床讲座 第六讲 感应同步器原理和应用

一、感应同步器的原理1.概述感应同步器是一种检测机械转角或位移的精密传感器。在系统中,它提供被测部件偏移基准点的角度或位置测量的电信号,以实现系统高精度的自动控制。它是决定随动系统精度的重要因素之一。感应同步器分为圆盘式和直线式两种。圆盘式测量的对象是转角,直线式测量的对象是直线位移。其工作原理和普通的旋转变压器很相类似,是利用定子和转子(或定尺和滑尺)的绕组之间随相对位置的变化所产生的电磁耦合的改变,从而发出相应的位移(或转角)的电信号。感应同步器的绕组分为激磁绕组和感应绕组两大部分(可分别称定子和转子),其绕组的     

感应同步器的零位误差

感应同步器是一种多极电磁感应式位移传感元件。由于具有精度高,结构简单可靠等优点,广泛应用在军事装备、测量技术、机床制造等部门,例如在制导、雷达、伺服转台、数控机床等设备中用来构成角度和直线位移的传送、读出或定位系统。感应同步器有旋转式和直线式两种。旋转式用来传送机械角度,精度可达1秒。直线式用来传送直线位移,精度可达1微米。     

圆感应同步器测角误差的分离技术

研究了圆感应同步器测角系统的测角误差的主要组成部分及其分离技术,通过对感应同步器测角误差的实测,提出了分离出长周期(360°)的一次谐波,短周期(1°)的一次谐波和短周期二次谐波的方法,并采用相应的软件和硬件补偿技术大大提高了感应同步器的测角精度。     

一种新型无轴承永磁电动机本体结构研究

通过对传统无轴承永磁电动机本体结构分析,针对其复杂的结构,分别从转子结构和定子结构进行优化,提出一种以永磁薄片式转子新型无轴承永磁电动机,并对工作原理及应用进行了分析.     

水氢氢600MW汽轮发电机机座底脚承载调整

采用端盖式轴承的大型汽轮发电机机组运行时,定子振动与转子振动相互耦合。如果机座底脚承载状态不理想,则有可能使发电机在运行时产生较大的机座振动。因此,在发电机安装调试阶段进行机座底脚承载调整是一个重要的环节。通过调整垫片使机座四角承载达到合理分布状态,从而可有效保障机座振动的稳定良好。本文介绍了机座底脚承载调整的方法及安装于吴泾第二发电厂的水氢氢600MW汽轮发电机的调试结果。     

大型水轮发电机几个关键技术问题的分析

本文对大型水轮发电机定子、转子和推力轴承等主要部分的几个关键技术问题进行了分析论证,提出整圆装压、合理选取机座刚度、提高定子铁芯和磁轭压紧力、推广双向变极距磁轭叠片方法、采用圆盘式转子支架及大面积支承液压弹性推力轴承等大型水轮发电机技术改进方向和途径.     

考虑低速稳定性的感应电机转子磁场定向校正策略

感应电机的转子磁场定向控制中,磁场定向角的准确性影响着电机的转矩输出性能。在速度测量准确的场合,转子定向角主要受转子电阻误差的影响,而转子电阻校正又受到定子电阻误差的影响。目前,较少的论文对转子电阻和定子电阻同时进行补偿,且同时补偿下的稳定性问题也鲜有研究。该文提供了一种新型的基于MRAS的转子电阻和定子电阻补偿策略,经李雅普诺夫稳定性理论验证,该策略可以保证系统在低速下的稳定性。经5.5 kW试验平台验证,该策略可以有效提升转子磁场定向控制在低速下的转矩输出性能。     

一种新颖的永磁同步电动机无位置传感器技术

无位置传感器技术是永磁同步电动机调速系统的一个发展方向.本文剖析了已有的两种典型直接估算方法,提出了一种新颖的无位置传感器技术.通过分别计算出定子磁链矢量角位移与转矩角,将后者从前者中减去得到转子磁链矢量的角位移进而得到转子速度信号,并采用改进积分器取代传统的积分器.该技术能有效地改善磁链原点漂移,提高直接转矩控制系统的磁链角位移与转速的求解准确度.仿真及实验研究结果表明,采用这种无位置传感器技术的永磁同步电动机调速系统,具有良好的调速控制性能.     

高压高效管式隔爆型三相异步电动机设计

设计了一种高压高效管式隔爆型三相异步电动机。介绍了该电机的整体结构及定子、机座、转子、风扇、轴承、接线盒设计特点。该电机在电机效率、圆周偏心布管、高强度隔爆件、轴贯通曲路、稀油润滑滚动轴承、高防护、低振动、低噪声等设计方面具有创新性。通过产品样机测试试验和数据分析证实了该电机的先进性。     

Influence of the Operational Wear of the Stator Parts of Shroud Seals on the Economic Efficiency of the Steam Turbines

During the operation of steam turbines under transient conditions, due to different thermal expansion of the stator and rotor parts in the radial and axial directions, the clearances fixed in the course of assembling the seals of the flow path change, which causes rubbing in the seals and the wear of the latter. This inevitably increases the leakages through the seals. A particularly large difference in the relative axial and radial displacements of the rotor and stator parts is observed during the turbine start-ups when the difference in their temperature expansion is maximal. Upon the turbine stops, the turbine shafting runs down freely, as a rule, passing through all critical speeds at which the amplitude of the shafting oscillations reach their peak values, which also leads to seizures in the seals and their wear and tear. The seizures in the seals may also be a consequence of the eccentricity between the rotor and stator caused by the thermal strain of the stator, incorrect choice of the clearances, floating-up of the rotor in the bearing, and many other factors. Recently, standard shroud labyrinth seals are being replaced in the steam turbines by seals with honeycomb stator inserts, the design of which allows the ridges to cut into the honeycomb surface without damaging the former, which allows fixing a radial clearance in the seals of 0.5 mm. On the honeycomb surface where the ridges touch it, grooves are cut through. The wear of the shroud seals reduces the efficiency of the steam turbines during the operation to the greatest degree. However, by the present there have been no exact quantitative data available on the change in the leakage through the worn-out honeycomb seals. The paper presents the results of comparative experimental studies on the flow and power characteristics of seal models with smooth and honeycomb stator parts for various degrees of their wear. The studies showed that the leakages through the worn-out stator parts of the honeycomb seals increase approximately 1.7 times slower than under the similar wear of the ridges of conventional straight-through seals with smooth stator parts. However, this gain in efficiency achieved by replacing the standard smooth-wall seals with the honeycomb seals must be necessarily correlated with the measurement data on the nonconservative shroud forces in conventional axial-radial seals with smooth stator surfaces with a radial clearance of 4 mm, which is almost seven times lower than that in the honeycomb seals with a radial clearance of 0.5 mm. From the results obtained in the work, it follows that the installation of honeycomb shroud seals instead of traditional ridge seals in the high-pressure cylinders (HPCs) of the steam turbines for subcritical steam parameters with high-vibration-resistance rotors that have a sufficient margin of resistance to self-oscillations is undoubtedly advisable from the point of view of increasing the economic efficiency of the turbines. However, the use of honeycomb shroud seals with reduced radial clearances in the HPC parts of the steam turbines for supercritical steam parameters requires special cautiousness, since it is in the area of small clearances that the maximum nonconservative shroud forces capable of causing auto-oscillations of the shafting are observed and these forces are maximal precisely at high pressures.     

Rotor Rolling over a Water-Lubricated Bearing

The article presents the results of studying the effect of forces associated with secondary damping coefficients (gyroscopic forces) on the development of asynchronous rolling of the rotor over a water-lubricated bearing. The damping forces act against the background of other exciting forces in the rotor–supports system, in particular, the exciting forces of contact interaction between the rotor and bearing. The article considers a rotor resting on supports rubbing against the bearing and the occurrence of self-excited vibration in the form of asynchronous roll-over. The rotor supports are made in the form of plain-type water-lubricated bearings. The plain-type bearing’s lubrication stiffness and damping forces are determined using the wellknown algorithms taking into account the physical properties of water serving as lubrication of the bearing. The bearing sliding pair is composed of refractory materials. The lubrication layer in such bearings is thinner than that used in oil-lubricated bearings with white metal lining, and there is no white metal layer in waterlubricated bearings. In case of possible deviations from normal operation of the installation, the rotating rotor comes into direct contact with the liner’s rigid body. Unsteady vibrations are modeled using a specially developed software package for calculating the vibration of rotors that rub against the turbine (pump) stator elements. The stiffness of the bearing liner with the stator support structure is specified by a dependence in the force–deformation coordinate axes. In modeling the effect of damping forces, the time moment corresponding to the onset of asynchronous rolling-over with growing vibration amplitudes is used as the assessment criterion. With a longer period of time taken for the rolling-over to develop, it becomes possible to take the necessary measures in response to actuation of the equipment set safety system, which require certain time for implementing them. It is shown that the gyroscopic damping components facilitate the developing rolling of the rotor over the bearing. If measures taken to decrease these components in the damping devices and bearings are met with success, the onset of asynchronous rolling-over with the growing amplitudes occurs after a longer period of time.     

基于热网络的异步电机过载保护模型及数字算法

以试验样机为例,依据电机内部不同的发热源将电机分作五部分,即定子铁心和机壳、定子槽绕组、定子绕组端部、转子导条和转子铁心,分别应用集总参数法建立了五阶的热网络分布模型.在保证模型精度的前提下,利用零极点对消法对五阶热模型进行了降阶简化,从而得到了反应电机温升主要特性、精度高、计算简单的低阶热网络模型.对低阶热模型进行离散化,得到了适用于智能电机过载保护继电器的数字算法.     

Characteristic matching between stator and rotor in standing-wave-type ultrasonic motors

This work discusses kinematical and dynamic matching between stator and rotor in standing-wave-type ultrasonic motors. A remarkable feature of standing-wave-type ultrasonic motors is that the stator intermittently contacts the rotor. The dynamic responses of the rotor in rotary direction and in pre-pressure direction influence the performances of the motor. The responses in the two directions have been investigated independently, because the two degrees of freedom are orthogonal in physics. To enhance drive force, rotation velocity and to reduce noise, the contact not only must be short enough but also must occur in the largest velocity area of the stator in the rotary direction of the rotor. The discussions presented in this paper can be used for guiding in the design of standing-wave-type ultrasonic motors.     

基于定子电流矢量定向的异步电机转子磁链估计器及其应用研究

异步电机矢量控制的关键问题在于精确地估计转子磁链。然而，传统的磁链估计器的精度会因定子或转子电阻的摄动而降低。文中提出了一种基于定子电流矢量定向的转子磁链估计器。该新型估计器不包含定转子电阻，可以避免电阻参数摄动对估计精度的影响。开环和闭环的仿真结果表明，该估计器具有相当高的精度，并且在定转子电阻大幅度摄动时，估计结果几乎不受影响，显示出比传统的磁链估计器更强的抗扰动能力。     

A novel model of ultrasonic motors with effect of radial friction in contact mechanism

This paper is concerned with a development of the contact model of traveling wave type rotary piezoelectric ultrasonic motor, which takes into account a new three-dimensional operation mechanism between the stator and rotor. First the vibration characteristics and harmonic response of the stator are analyzed based on the mathematical model. With the derivation of the kinematical equations representing the motion of the stator surface points, the three-dimensional driving mechanism is investigated at the contact interface between the stator and rotor. We found that the distributed contact forces have not only the axial and circumferential components but also the radial component at the interface. The traditional contact model should be improved by the consideration of radial friction at the interface. So we defined driving angle α, which describes how the radial friction distributes at the interface. Furthermore it is shown that the radial friction can lead to considerable energy losses. A set simulation of motor performances based on the proposed contact mechanism is found in good agreement with experimental results. We also tried to explain how the applied normal preload force on rotor affect the natural frequency of stator by the contact interface, as is shown in our experiments.