OPTIMIZATION OF AN ELECTRONICALLY CONTROLLED CAPACITOR FOR A SINGLE-PHASE INDUCTION MOTOR

ABSTRACT

In this paper the performance of a single-phase induction motor with an electronically controlled capacitor is examined. The capacitor in series with the auxiliary winding is controlled with an electronic circuit and different optimization criteria are applied in order to determine the optimum capacitance of subsequent performance of the motor.     

REVOLVING-FIELD ANALYSIS OF TWO-SPEED SHUNTED CAPACITOR MOTORS WITH NONQUADRATURE WINDINGS

ABSTRACT

The main purpose of this paper is to extend the well-known revolving-field theory for the general development of the so-called analysis equations to predict the performance of two-speed shunted capacitor motors with arbitrary arrangements of their primary windings. It has been found that sometimes by arranging the auxiliary winding at an unconventional location, the motor efficiency can be considerably improved especially at low-speed setting. The accuracy of the present mathematical development has been confirmed by actual measurements on such motors with windings both in quadrature and nonquadrature     

HARMONIC FIELDS IN PHASE-SHIFT-MODIFIED POLE-CHANGING WINDINGS FOR POLYPHASE INDUCTION MOTORS

ABSTRACT

A recent article proposed a phase-shift-modification technique for developing two-speed pole-changing windings for polyphase induction motors. In this article the author investigates the harmonic mmf content of three of the windings proposed, making use of a procedure developed and published over a dozen years ago. The results are compared with the results of similar analyses on commonly used fractional-slot least-common-multiple windings; they are also compared with the harmonics in a pole-amplitude-modulated arrangement. This analysis reveals the existence of very serious harmonic mmfs in at least two of the three phase-shift-modified arrangements proposed in the recent article, and shows the third arrangement to be much better, though still somewhat inferior to the other windings analyzed.     

变频调速异步电机的优化设计

随着变频调速技术的发展，异步电机在工业传动领域中的应用越来越广泛。传统的异步电机设计方法已经不适应变频调速异步电机的设计要求。传统电机的设计重点在于额定点效率、功率因数、最大转矩、起动转矩、起动电流、运行温升和价格等指标。而变频调速电机的设计重点是在调速范围内的效率、功率因数、温升，以及动态响应性能等。本文根据变频调速集成系统的特点，提出具有针对性的变频调速电机优化设计策略。该策略具有以下几个特点：①采用自适应设计模型；②针对变频器供电的谐波影响分析模型；③采用最优滑差控制和面向系统的优化设计方法。利用该优化设计方法，使得变频调速异步电机更加高效节能。     

TRANSIENT ANALYSIS OF CAPACITOR MOTORS USING DYNAMIC PHASE COORDINATES THEORY

ABSTRACT

This paper explains further development of phase co-ordinates theory as related to a specific type of single phase induction motors. Specific tests to find the parameters of the motor, and transient tests to verify the accuracy of the model carried out on the actual motor. The full-load run-up test results are satisfactorily compared with those obtained from the phase model analysis.     

ABOUT THE DESIGN OF VERY HIGH FREQUENCY INDUCTION MOTORS FOR SPINDLE APPLICATIONS

Abstract

In the paper the authors deal with induction motors used in electrical spindles and fed by high frequency inverters. The design problems of high frequency machines are analyzed by the electromagnetic, the mechanical and the thermal points of view. The possibility to use the classical relations adopted to calculate the equivalent circuit parameters for standard motors at 50?Hz is carried out and the results are compared with the experimental ones. A brief overview of problems related to the mechanical design (bearings, lubrication, shaft stiffness) and to the thermal design is reported. Finally, starting from both the simulation and the experimental results, some specific criteria for the electromagnetic design are well focused.     

基于回路电流法的双抽头单相电机的网络方程

借助于异步电机的等值电路,采用了与传统的交轴磁场法和旋转磁场法不同的分析方法。该方法通用性强,适于分析定子绕组具有各种不同连接方式的异步电机的稳态运行性能,并能列写出便于计算机辅助计算矩阵方程。以定子绕组连接复杂的双抽头单相电机为例,该方法把该电机的定子电路分成了2个回路和6条支路,选择其中的1条支路作为基准支路,转子绕组向基准支路中的绕组折算,各支路绕组中的正序与逆序感应电势当作流控电压源进行处理,然后由回路电流法列写出了计算电机性能的网络方程,为验证计算结果,给出了1台双抽头单相电扇电机某些电流与电压的计算值,并与实测值作了比较,计算值与实测值的相互吻合说明了网络方程的正确性。     

三相异步电机在单相电源供电时稳态运行性能的分析和计算

基于分析和单相电机稳态运行的等效电流法。结合近代电路理论中网络图论的有关内容,推导了三角形接法三相异步电机在单相电源供电时,以矩阵形式表示的性能计算公式。将计算值和实验值进行比较的结果表明,两者是比较接近的。     

CONCEPT OF BUILT-IN RELIABILITY IN THE DESIGN OF LARGE INDUCTION MOTORS

ABSTRACT

In recent years, the reliability study of the equipment has been given vital importance alongwith the other studies. In this paper, an attempt is made to construct the reliability model of a large induction motor in order to predict the reliability, with the knowledge of realistic failure data. Since the author is not aware of any failure data, the prediction is based on some realistic failure data. However, in this paper the basic concepts are laid down, to ensure reliability goal of each component in the design stage. It is also emphasised here, the effect of supply conditions, ambient and malfunctioning of accessories in induction motor on its reliability goal. The method of attack is based on Markov model, by judiciously choosing ‘Available’ states and ‘Failed’ states. This method affords better realisation of failure modes and possible decisions to improve the same. The theory of reliability is presented in short, in order to make the ideas presented in this paper, more clear. A numerical example is presented at the end, to elucidate the theory presented here.     

电动机节能模糊控制器

为提高感应电动机的运行效率，本文提出了电动机节能模糊控制器的实现策略，设计了电动机调压节能模糊器和调频节能模糊控制器原型。它的基本原理是，在保护负载需求的前提下，通过控制电动机的定子电压或频率，最大限度地减少其输入功率，以实现节电运行。模糊控制器的输入变量是定子电流及其变化率，输出变量是定子电压或与频率对应的ＰＷＭ脉冲序列。本文所提出的节能模糊控制器的特点是成本低，鲁棒性强，模糊推理和ＰＷＭ脉冲序     

A NEW PHILOSOPHY FOR SPEED-CHANGE INDUCTION MOTORS

ABSTRACT

A new concept termed ‘phase shift modification’ for the design of two-speed single-winding three-phase induction motors is discussed. Designs are classified based on the chosen phase-spread on the initial and final pole scales. A method for improving the layer factor on the final-pole connection without affecting the winding factor for the initial pole connection is also presented. Although the concept is illustrated with respect to a 8/10 pole-combination it is equally applicable to any other pole-ratio.     

OPTIMIZATION OF DUAL SPEED INDUCTION MOTORS

ABSTRACT

Design optimization of single-winding dual speed and double-winding dual-speed three phase induction motors is attempted. The choice of independent variables and the specification of the performance requirements for these two types of motors are discussed. The formation of an objective function end the various steps involved in the minimization process are explained. It has been shown that comprehensive computer programs can be developed to design optimum dual speed motors of any pole ratio with any stator coil span and winding connection.     

SPLIT-WINDING STARTING OF A SINGLE-PHASE INDUCTION MOTOR

Abstract

Results of investigation of starting a single-phase induction motor having a single stator winding and using normal stator and rotor punchings are presented in this paper. Theoretical and experimental studies show that the motor requires less copper for its stator winding compared to a split-phase motor and the overall starting performance is very satisfactory.     

感应电机无速度传感器矢量控制系统的定子电阻在线辨识

该文针对利用磁通观测器推算转子磁通的感应电机无速度传感器矢量控制系统，提出了定子电阻在线辨识法。在利用q轴磁通推算转速的基础上，该系统利用d轴磁通误差实现定子电阻在线辨识，该方案的优点是系统简单，解决了低速运行时电压模型的定子电阻变化对系统稳定性和速度控制精度的影响问题。数字仿真和实验结果验证了定子电阻在线辨识的必要性和该方案的有效性。     

利用双极对槽号相位图设计单相交流电机的变极绕组

该文提出设计单相交流电机变极绕组的基于双极对槽号相位图的设计方法。以24槽4/6极绕组为例说明了该方法的应用。结果表明,该方法比传统的基于槽矢量星形图的设计方法要方便和有效。     

新型软起动最小转矩脉动的控制策略研究

研究了基于自关断器件的新型软起动。分析了新型软起动的摹本原理和工作特性，给出了软起动系统的数学模型，重点研究了电机起动过程中的转矩脉动问题。在仿真分析电机连接三相系统时定了电压的第一个系统周期内开关时刻与转矩脉动关系的基础上，给出了转矩脉动的控制策略。利用开关时刻计算函数，得到施加电压的最佳开关时刻。按照此开关时刻施加电压，可以减小甚至消除电机起动时的脉动转矩。实验结果证明该方法对于新型软起动是切实可行的。     

TRANSIENT PERFORMANCE OF A GROUP OF INDUCTION MOTORS

ABSTRACT

The paper develops the non-linear differential equations which describe the transient behaviour of a group of parallel-connected induction motors, either when fed from a stiff supply or when the supply is weak and the machine behaviour is interactive. A digital-computer solution of these equations provides a numerical prediction of the transient currents, voltages, torques and speeds of a laboratory-scale group of motors, in close agreement with experimentally-obtained results.     

A COMPANION CIRCUIT MODEL OF INDUCTION MOTORS

ABSTRACT

The theory of a companion circuit model of the induction motor is presented. The model comprises an independent current source in parallel with a constant resistance. Accuracy of problem solutions is the same as that obtained from conventional models, but the time of solution is much shorter. This stems from the combined consideration given to the problem formulation and its solution. A companion circuit model can include extra sets of machine coils such as those needed to represent deep-bar effects. Conventional motor models are adequate for single-machine, transient studies. It is for multi-machine studies that the companion circuit concept provides advantages for formulation and solution.