无滑环绕线转子感应电动机的实际应用

针对传统绕线转子感应电动机由于转子回路串接电阻的起动模式所带来的一系列技术问题,本文提出转子回路无滑环碳刷不串接电阻的变极谐波起动方案。该方案针对大型绕线转子电机的特点,提出一种实现谐波起动的定子绕组新接法,该方法引进了"全绕组起动"的概念构造。正常运行时又可换接为标准绕组,转子绕组则采用"无感"的概念和复合线圈技术,新型绕线转子电机同样具有高起动转矩、低起动电流。同时它还具有高可靠性、高功率因数、高效率、高过载能力、低转差损耗的特点,节能效果明显。     

Modified Steady-State Analysis of the Current-Source Inverter and Squirrel Cage Motor Drive

The "modified" steady-state analysis of the current-source inverter (CSI) drive given in this paper includes the effects of the following factors neglected in the ``conventional' analysis given in present literature: 1) the variation of the ac back electromotive force (EMF) of the induction motor (load) during commutation, and 2) the phase shift of the fundamental component of the line current due to the finite commutation interval. It is shown that the effective leakage inductance of the motor during commutation is lower than the value obtained by the low-frequency blocked rotor test. A procedure for measuring the effective leakage inductance is given. At high stator frequencies the inverter operation is influenced by the conduction of series diodes outside their usual 120° period. A method of calculating the ``critical' frequency where this effect begins to occur is given.     

Constant Torque Operation of Induction Motors Using Chopper in Rotor Circuit

A novel control scheme is investigated for operating induction motors in the constant torque mode. The basic control schemes and analysis of the steady-state performance of the system are presented. Circuit models are used to predict the performance characteristics. A new dc dynamic braking method is proposed and studied that provides very fast braking. Experimental results are presented to verify the theoretical predictions and demonstrate the feasibility of the control schemes.     

隔爆型绕线转子三相异步电动机实现无刷自启动的探讨

从隔爆型绕线转子电机性能优点、结构缺陷和鼠笼电机性能局限、结构优点的两个方面出发，分析隔爆型绕线电机实现无刷自启动之后的独特优势。再从常规所串转子电阻特性、防爆安全性等方面，探讨隔爆型绕线转子三相异步电动机实现无刷自启动的方法与可能性。     

变频器供电情况下感应电动机转子断条的诊断

变频调速技术的应用已遍及各个控制领域,同时由变频器高速通鄄断开关作用所带来的电磁干扰问题也引起了人们的关注。文章对变频器供电情况下感应电动机定子电流信号中的各谐波分量及电磁干扰问题进行了分析研究,提出了减少测量电路干扰的有效方法。在此基础上,用时变频谱分析法实现了感应电动机转子断条的诊断。     

Detection of Winding Faults in Wound Rotor Induction Motor Using Loci of Direct and Quadrature Axes of Rotor Currents

In this paper, loci of direct and quadrature axis of rotor currents are used for online detection of winding fault on stator side as well as rotor side in three-phase wound rotor induction motor. The proposed technique is used for detecting load on induction motor and open circuit fault condition on stator side as well as rotor side. Detection of winding fault is affected by unbalanced supply voltage. In order to overcome this problem, FFT of modulus of direct and quadrature axis is used. The experimental results of rotor current analysis are validated with stator current analysis. Research works reported in the literature are based on stator currents analysis. The proposed technique of detecting winding faults and distinguishing between stator winding faults and unbalanced supply voltage using rotor current is not reported in the literature.     

异步电动机铸铝转子溶铝原理及工艺操作过程

0 引言 异步电动机铸铝转子有时因铸铝的质量问题,运行中铝导条断裂、铝导条溶化、铝液甩出等造成堵转停车,难以修复,需将铸铝全部清除.     

次级断续时直线感应牵引电机的等效电路

直线感应电机作为轨道交通车辆的牵引电机,在道岔、转弯等路段会出现次级感应板缺失的情况,次级连续时的等效电路不再适用.针对此特殊工况,提出一种基于气隙磁通密度的分布模型,考虑次级断续的等效电路.首先,建立直线感应电机次级断续时的分析模型,根据初、次级耦合情况把断续工况分成三个阶段.然后,利用线性近似化法修正随耦合区域长度...     

次级断续时直线感应牵引电机的分段式等效电路与特性分析

提出分段式等效电路模型,分析了次级断续时直线感应牵引电机特有的电磁现象及其特性.首先,建立次级断续时直线感应电机的物理模型,根据初级、次级的耦合情况将初级通过断续区域的过程分为九个阶段.其次,提出分段式等效电路模型,分析次级断续时等效电路参数的变化情况.然后,考虑初级铁心有限长、横向和纵向端部效应、趋肤效应和初级半填充...     

浅谈隔爆型绕线转子三相异步电动机的启动、调速控制特性

本文主要介绍了隔爆型绕线转子三相异步电动机的特点,叙述了绕线式三相异步电机的几种常用的启动、调速方法,对比了各种启动、调速方法的优缺点。     

双定子实心转子盘式异步飞轮电机新型等效电路模型分析

双定子实心转子盘式异步飞轮电机具有可高速运行、可靠性高、结构简单、成本低等优点,可作为低成本的飞轮储能系统中电动/发电机用.该电机的等效电路模型与参数对于性能分析、推导控制策略至关重要.针对该电机的结构特点,根据实心转子内磁场分布规律,采用分环分层法以及表面阻抗理论推导了一种新型等效电路模型,该新型等效电路模型相比于传...     

A New Control of PWM Inverter Waveform for Minimum Loss Operation of an Induction Motor Drive

A simplified method to calculate harmonic currents of an induction motor and optimum PWM switching patterns to minimize the harmonic loss are presented. Neglecting the harmonic iron loss, the harmonic loss of the motor is proportional to the square of the rms current. The waveform of the harmonic current is approximately equal to that of the leakage reactance applied to the same PWM voltage. Its approximation error is very small under normal operating condition. The main results obtained using these approximation are as follows: 1) the optimum PWM patterns of the pulsenumber from seven to 41; 2) how to choose the optimum pattern and calculate it by using a computer; 3) the effect of a resistance of the windings and skin effect of the secondary conductor; and 4) microcomputer PWM optimum voltage control schemes. Comparison with other controls is shown by using experimental and calculating results and confirms the effectiveness of this control scheme.     

基于三电平逆变器的异步电动机直接转矩控制

构建了基于二极管中点钳位型三电平逆变电路的异步电动机直接转矩控制系统。在对控制系统进行深入理论分析的基础上,提出了一种简单的开关矢量选择方案,有效地实现了矢量选择与中点电压平衡,并通过仿真分析验证了所提出算法的有效性。该方案适合应用于大容量传动场合。     

计及变频器的感应电动机负荷特性分析

感应电动机是电力系统中最常见的动态负荷类型,其负荷特性对电力系统运行有着重要影响。当前随着变频器在工业界的广泛应用,带变频器的感应电动机负荷特性与传统感应电动机负荷存在很大的不同。通过建立带PWM变频器感应电动机的数学模型,研究其有功功率P和无功功率Q在稳态低电压及故障动态时的变化情况,分析了计及变频器的感应电动机负荷特性,并与传统感应电动机负荷进行比较。     

High Response Control of Stator Watts and Vars for Large Wound Rotor Induction Motor Adjustable Speed Drives

Extremely rapid control response (0.01 s) of stator watts and vars has been obtained on a 15 000-hp wound rotor induction machine with a cycloconverter controlled secondary by means of an orthogonal control scheme which linearizes the machine equations and combines both feedforward and feedback error signals. Leading and lagging power factor and positive or negative stator power flow can be smoothly and rapidly controlled over a speed range in excess of ±35 percent of the induction motor synchronous speed. This doubly fed drive may be termed a "Scherbiustat drive" because the wound rotor induction motor secondary power conversion equipment is the static equivalent of the Scherbius machine. This type of a drive does not employ a dc link in the motor secondary power conversion equipment. It should not be confused with a static Kraemer drive which employs a dc link in the frequency conversion process and was so named because of its similarity to the original Kraemer drive which uses a synchronous converter and a dc motor in the secondary power conversion process. Recently obtained field results have verified the original study results discussed herein.     

大型绕线转子异步电动机烧损原因分析

介绍了一起大型绕线转子电动机运行中转子绕组烧损的事故经过,根据现场情况和历史数据,对事发过程进行了全面分析,解释了故障发生的原因,并提出了预防措施。     

Induction Motor Rotor Temperature Estimation Based on a High-Frequency Model of a Rotor Bar

This paper analyzes a high-frequency (HF) voltage-injection-based rotor winding temperature estimation method for current-regulated squirrel-cage induction motors (IMs). We develop a theoretical HF model of the rotor bar and then first provide an analysis of relevant HF model-based estimation aspects, such as the dependence of the rotor leakage inductance on the temperature and the relationship between the rotor resistance and rotor leakage inductance. We also include an analysis of magnetic saturation to improve the estimation accuracy, as well as an analysis of the phase delay effect resulting from the drive that significantly affects the HF signal precision. Then, a specialized offline commissioning scheme is proposed to compensate for the effect of the phase delay and magnetic saturation. The estimation technique and sensitivity analysis are verified by means of experiments performed on an inverter-fed 1.5-kW IM.     

双鼠笼感应电动机的结构及转子槽形设计

介绍双鼠笼感应电动机的结构特点、转子上下导条在电机起动与运行中的作用、转子导条的不同形状、导条材质的选择和转子槽形的类型,并展示了两种转子槽形的比较结果及它们在电机设计中的适用性。     

一种简单有效的感应电机转子参数辨识方案

本文选择了以间接矢量控制为基本方法，采用ＤＳＰ为计算与控制中心的方案，进行了感应电机转子参数辨识方法的研究。针对影响感应电机高效率、高性能运行的转子时间常数随时间变化的问题，提出了一种新的在线自适应辨识方法。并对所述系统进行了实验室的小功率拖动实验，达到了预期的效果。     

一种高性能逆变电流源的分析与设计

介绍一种用于电工仪表测试的高精度,高稳定性电流源。