一种基于磁化曲线分析瞬态饱和的异步电机空间矢量的新方法

提出一种用空间矢量表示的异步电机瞬态饱和的数学模型.该模型的分析方法有别于传统的磁路饱和处理方法,直接利用异步电机空载磁化曲线来考虑磁路饱和对电机的影响,进而推导出异步电机瞬态饱和非线性数学模型.利用该模型对异步电机进行Matlab实例仿真.结果表明,该模型较之线性模型有一定的改进.     

内置式永磁电动机的饱和参数与矢量控制分析

内置式永磁同步电动机的参数直接影响矢量控制的性能,本文提出了采用一元函数表示内置式永磁电动机磁路饱和的电感参数,给出了考虑q轴磁路饱和的电感参数的计算公式和电机数学模型,推导了相应的矢量控制的运行轨迹和控制方程。q轴饱和电感参数与全面考虑d、q轴磁路交叉饱和的参数相比,其计算量大大减少,且便于实际测量,相应的矢量控制方法与采用线性参数的控制方法基本没有区别。为了验证提出的q轴磁路饱和的电感参数的准确性,采用q轴饱和电感参数对矢量控制的运行转矩和磁链进行了计算,并与考虑了电机全部磁路饱和的电磁场计算结果进行了对比分析,证实了只考虑永磁磁势交叉饱和与全面考虑交叉饱和的结果有较好的吻合。     

异步电机电流内模解耦控制系统分析与仿真

在同步速d-q坐标系下异步感应电机动态模型和解耦控制原理的基础上引入了内模控制方法,详细设计了基于转子磁链定向和内模控制的定子电流调节器。为了计及实际系统中异步感应电机磁场会随着电机负载(转矩)变化而呈不同程度的饱和以致电机参数的非线性,分析了电流内模控制器对这种非线性参数的鲁棒性,建立了整个异步感应电机矢量控制仿真系统,并分别对忽略磁路饱和和考虑磁路饱和两种情况下的系统进行了仿真分析。结果表明电流内模控制调节器在模型匹配和失配下均能提供良好的转矩动和静态解耦效果。     

九相感应电机切套运行的非线性磁路计算

多套多相绕组构成的感应电机发生缺相故障时可以切出故障相所在的整套绕组,电机工作在切套运行状态。为掌握电机切套运行时的精确性能指标,以三套三相绕组构成的九相感应电机为研究对象,应用分布磁路法计算了电机相数和励磁电流均发生变化后的非线性磁路,得到工作范围内励磁电流与励磁电感的对应关系,通过非线性插值即可求得任意励磁电流下计及饱和时的励磁电感。利用有限元法对九相感应电机不同切套工况进行仿真验证,仿真结果与分布磁路法计算结果相吻合,验证了磁路计算结果的正确性。     

考虑磁路饱和的内置式永磁同步电机电感参数旋转辨识算法

实现对永磁同步电机调速系统高性能控制的基础是准确的数学模型和电机参数,其中电感参数对电机的稳态和动态运行性能影响较大,而对于内置式永磁同步电机而言电感除了受凸极结构影响之外,还受磁路饱和等因素的影响。考虑到定子电流引起的磁路饱和效应与交叉耦合效应对电感的影响,基于矢量控制技术分别提出了d轴和q轴电感旋转辨识新算法,即d轴复合电流激励法和转矩调整法。为了提高电感辨识准确度,还采用基于电压误差曲线的补偿算法对逆变器非线性因素引起的输出电压误差进行了补偿。最后在电机控制实验平台上通过实验验证了提出的电感辨识算法的可行性和有效性。     

快速非线性仿真法在开关磁阻电机等效磁网络模型中的应用

针对开关磁阻电机的双凸极结构特点和严重的磁路饱和现象，提出了一种等效磁网络模型和快速非线性仿真法相结合的方法，实现了开关磁阻电机性能计算的准确性和快速性的协调统一，既建立了准确的数学模型，又实现了运行性能的快速仿真，为开关磁阻电机的优化设计奠定了基础。     

感应电动的磁路非线性及其在控制策略中的考虑

本文从理论上分析了感应电动机磁路线非线性现象，并讨论了其对矢量控制的效应；基于自适应模型参考跟随系统理论提出了一种新的感应电动机高性能控制策略。     

混合磁路电机的哈密顿建模与控制

针对电机传统控制策略对参数变化敏感等问题,从能量的观点出发,将哈密顿能量系统理论应用于混合磁路电机,将混合磁路电机数学模型表示成了广义耗散哈密顿系统的形式,给出了混合磁路电机的哈密顿能量函数,设计了混合磁路电机的非线性稳定控制器和负载观测器。仿真结果验证了理论分析的正确性和控制律的有效性。     

超高功率密度感应电机电磁场及转矩特性分析

超高功率密度感应电机存在非线性现象,如齿槽效应、挤流效应、电涡流效应、饱和效应等,和普通感应电机比,尤其突出,严重影响电机电磁场的分布。传统的磁路分析方法很难准确分析这些非线性现象对电磁场分布的影响。文章利用有限元分析软件(ANSYS)对某1.8kW/kg的超高功率密度感应电机在不同运行状态下的电磁场分布以及转矩特性进行了详细研究,精确地描述了这些非线性现象对该型电机电磁场的分布和电磁转矩的影响,对超高功率密度感应电机的电磁场设计和分析有一定指导作用。     

12/8极双通道开关磁阻电机非线性数学模型与有限元分析

与传统的12/8极开关磁阻电机不同,双通道开关磁阻电机线圈之间采用一对极绕组反向串联的结构形式,由两套独立的功率电路驱动形成新型的双通道控制系统,该系统能够实现容错控制以提高可靠性.本文在分析双通道开关磁阻电机原理和结构的基础上,建立了电机每个通道绕组的磁路等效数学模型,在一个相周期内对磁路各部分磁导进行了详细分解计算,确定了以磁导表示的磁通矩阵,推导出绕组自感及各相之间互感的计算方法.该模型考虑了电机轭部磁路和材料非线性磁饱和的影响,提高了模型的实用性.有限元分析结果验证了该数学模型的正确性.     

ROTOR FLUX COMPUTATION IN SATURATED FIELD-ORIENTED INDUCTION MACHINES

ABSTRACT

The paper discusses effects of main flux saturation in field–oriented induction machines and proposes improved schemes for rotor flux space vector calculation. Field–oriented control with rotor flux computation out of the measured quantities is elaborated. Two rotor flux computer structures are analyzed. The first one is based on stator voltages and currents as measured variables, while the second scheme carries out calculations on the basis of sensed stator currents and rotor speed (position). The sensitivity of the constant parameter rotor flux computers to saturation degree variation is investigated in detail. Modified structures of the computing schemes are then proposed, which account for change in saturation level in the machine. The modified rotor flux calculators are derived from flux state–space model of a saturated induction machine. Accurate computation of rotor flux space vector is enabled in this way, irrespective of the actual saturation level in the machine. Verification of the developed modified rotor flux computers, which account for main flux saturation, is provided by the aid of digital simulation.     

FIELD-ORIENTED CONTROL OF INDUCTION MACHINES IN THE PRESENCE OF MAGNETIC SATURATION

ABSTRACT

This paper presents derivation of the equations which describe field-oriented control of saturated induction machines. Field-oriented control principles are applied on the saturated model of induction machine and new equations are obtained, which differ significantly from the well-known model valid when the main flux saturation is absent or neglected. Rotor flux oriented control of voltage-fed and current-fed saturated induction machines is discussed. New decoupling circuits which are needed under saturated conditions are presented. Simulation results, which show the influence of main flux saturation on transient behaviour of the drive and which verify the theoretical results are included.     

同时考虑铁损与磁饱和的异步电动机模型研究

根据交流异步电动机理论,提出了一种同时考虑铁损与主磁路饱和的异步电动机非线性数学模型。根据该数学模型在MATLAB/Simulink中搭建了仿真模型。最后以实际电机为例,利用仿真模型对异步电动机启动过程进行了动态仿真研究,验证了模型的正确性。     

Modeling of saturated AC machines including air gap flux harmoniccomponents

A new saturation model for induction machines that can be easily extended to other types of AC machines is presented. It is shown that saturation is responsible for the generation of flux space harmonic components traveling in the air gap with the same synchronous speed as the fundamental flux component, with the third being the dominant harmonic component. Superposition of the effects of the fundamental and third harmonic components of the air gap flux is utilized in order to model the saturation of the ferromagnetic parts of the machine. The concept of winding functions is used to derive the inductance terms relating to both stator and rotor winding components. In this approach, the air gap length is assumed to be variable, being a function of the position and level of the air gap flux. Terminal and torque values for steady and transient states are obtainable from the proposed model, with experimental results showing that the model proposed predicts spatial saturation effects with good accuracy     

Leakage flux saturation effects on the transient performance of wound-rotor induction motors

The prediction of induction machine performance has traditionally been based on the constant parameter models. This approach was later replaced by considering saturation in the main flux paths. However, such models have not been sufficiently accurate for certain transient conditions such as on-line starting and short-circuit. So, an accurate study of their performance should necessarily consider the magnetic saturation effect both in the main and leakage flux paths. In this paper, an experimental procedure to determine the machine parameters and saturation characteristics is adopted. The adopted experimental procedure facilitates the measurement of both stator and rotor leakage reactance saturation characteristics. Two models of saturated induction motors are developed to predict the transient performance of a laboratory wound-rotor induction motor. The results calculated by the proposed models considering and ignoring the leakage flux saturation are compared with the experimental results. The model that considers saturation in the leakage flux paths produces more accurate transient responses.     

Compensation of Parameter Variation Effects in Sensorless Indirect Vector Controlled Induction Machines Using Model-Based Approach

The majority of speed estimation schemes for sensorless vector control of induction machines use a mathematical model of the machine in the estimation process. These schemes are therefore inherently sensitive to parameter variation effects in the machine. The variety of speed estimation methods makes any attempt to develop a universal approach to compensation of parameter variation effects impossible. This paper concentrates on one of the most frequently used schemes, in which speed is estimated using model reference adaptive control approach (MRAC) on the basis of two estimated values of the rotor flux space vector. The estimator is analyzed in conjunction with indirect feed-forward rotor flux-oriented induction machine. An attempt is made to improve the accuracy of the speed estimation by appropriate modification of the speed estimator and the indirect vector controller structures using modified induction motor models that account for one or more of the phenomena that are neglected in development of the basic constant parameter scheme. In particular, compensation of main flux saturation, compensation of iron loss, and simultaneous compensation of both the iron loss and main flux saturation are elaborated. Novel structures of the speed estimator are developed for each of the three cases and are applied in conjunction with the appropriate modified form of the indirect rotor flux-oriented controller. Excellent compensation capability is demonstrated in all the cases by performing extensive simulation studies.     

感应电动机矢量控制参数离线辨识技术

详细介绍了感应电动机矢量控制系统电机参数的一种离线辨识技术.这种参数辨识技术基于电机的动态数学模型,通过在电机端注入直流或者单相交流电流,测量相应的电压响应,辨识出电机的定子电阻、转子电阻、定子瞬态电感和转子时间常数.最后通过大量的仿真和实验结果证明了参数辨识算法的正确性.     

Space vector PWM control of dual three-phase induction machineusing vector space decomposition

The technique of vector space decomposition control of voltage source inverter fed dual three-phase induction machines is presented in this paper. By vector space decomposition, the analytical modeling and control of the machine are accomplished in three two-dimensional orthogonal subspaces and the dynamics of the electromechanical energy conversion related and the nonelectromechanical energy conversion related machine variables are thereby totally decoupled. A space vector PWM technique is also developed based on the vector space decomposition to limit the 5th, 7th, 17th, 19th,... harmonic currents which in such a system would be otherwise difficult to control. The techniques developed in this paper can be generalized for the control of an induction machine with an arbitrary number of phases     

An improved model of saturated induction machines

Conventional models of induction machines represent instantaneous saturation of the magnetizing flux either by using saturation factors or by adjusting the tangential and slope reactances. These models are often inaccurate in predicting states of the machine during transient conditions such as online starting. To remedy these inconsistencies, an improved equivalent circuit model is proposed that accounts not only for the saturation effects in the stator and rotor teeth but also, independently, for saturation in both the rotor and stator cores. The model is compared with test results as well as with more conventional models. The model demonstrates an improvement over other known models showing that detailed representations of saturation effects could be important in induction machine analysis, particularly when the machine is subjected to large signal disturbances