A general nonlinear model of switched reluctance motor with mutual coupling and multiphase excitation

This paper presents a general nonlinear magnetic equivalent circuit model of a switched reluctance machine (SRM) that includes all possible flux paths in 2-D view of the machine, taking into account mutual coupling between phases and multiphase excitation. The model can be used to predict the performance of the machine with short or full pitched winding in static and dynamic regimes. Therefore, it is a simple analysing tool for finding the best configuration of SRM in computer-aided design and optimal design. A novel technique is employed to model the lumped elements of stator and rotor poles, and a new representation of the rotor core is introduced. Also, a general numerical matrix procedure is developed to calculate the total machine torque, and an approximate analytic alternative is presented. Inclusion of the rotor skew in the new model is described, and the accuracy of the model is verified by comparison of the simulation results with those obtained by the finite element method and measurements. Received: 6 December 2001/Accepted: 13 December 2001     

Design considerations for the switched reluctance motor

Analytical design equations are developed to predict the performance and to guide the design of the switched reluctance motor (SRM). The use of these analytical equations to trade-off different SRM attributes is discussed. The various approximations and simplifications used in the development of the analytical design equations are justified using results obtained from a detailed computer model of the SRM and by using experimental results from a high power density SRM designed for an aircraft engine fuel pumping application. Comparisons of predicted and measured machine performance parameters for this 90 kW 25000 r/min machine, such as flux linkage curves, back EMF, electromechanical power converted, and inverter voltampere requirements are presented. It is also shown that there exists a fundamental maximum torque density that is attainable with the SRM and an estimate of this maximum torque density limit is given. The power factor for an SRM is defined and the machine parameters that determine its value are presented. This power factor is compared to the similarly defined power factor for an AC machine and found to be smaller     

开关磁阻电机转子动力学建模与分析

超高速电机和普通电机相比,在功率密度、体积重量和传动效率上具有明显的优势,在航空航天、能源、高速加工等军事和民用领域具有广泛的应用前景。由于开关磁阻电机(SRM)具有结构简单坚固,转子上无永磁体和绕组,对高温等恶劣环境适应能力强等优点,最具开发成超高速电机的潜力。转子动力学设计是旋转机械设计中的重要环节。本文计算了开关磁阻电机偏心转子在各种电流和偏心度下的不平衡磁拉力,并在此基础上提出了开关磁阻电机不平衡磁拉力特有的脉冲性。作者建立了开关磁阻电机转子动力学模型,实现离心力和电磁力的解耦,并进行了一系列的仿真,为高速开关磁阻电机的设计提供参考依据。     

基于最小二乘支持向量机的开关磁阻电动机建模

开关磁阻电动机(SRM)的磁化曲线族是电机建模及性能分析的基础，文中探讨了利用最小二乘支持向量机处理磁化曲线族，建立电机模型的方法。在分析电机非线性磁特性的基础上，运用最小二乘支持向量机(LS-SVM)的回归理论，通过对磁路有限元分析法(FEM)得到的样本数据集进行学习，建立了电机的最小二乘支持向量机模型。与以往的神经网络建模方法相比，该模型在小样本情况下有更好的泛化能力及更快的学习速度。仿真实验表明，该模型比较准确地反映了电机的磁特性，可用来进行SRM其它性能指标的分析。     

开关磁阻电机定子振动的有限元分析

开关磁阻电机(SR电机)定子固有频率的研究对降低电机的噪声和优化控制策略有重要的意义,本文给出了SR电机振动模态分析的数学模型,利用ANSYS有限元软件对不同求解模型进行了详细的计算和分析.结果表明,考虑散热筋、机座和接线盒的三维模型的有限元分析结果与实验测得值有较好的一致性.     

遗传优化的最小二乘支持向量机在开关磁阻电机建模中的应用

针对开关磁阻电机的非线性磁链特性,用最小二乘支持向量机(least square support vector machine,LSSVM)与自适应遗传算法相结合的方法精确构建开关磁阻电动机的磁链模型。在最小二乘支持向量机通过采样数据训练模型的过程中,用自适应遗传算法评价拟合误差,优化LSSVM模型的超参数,进而优化开关磁阻电机的磁链模型。通过比较该模型的预测数据与实际测量数据,可以得出用自适应遗传算法优化的最小二乘支持向量机构建的开关磁阻电机模型是可行的,有较高的精度和较好的预测能力。     

基于变结构模糊神经网络的开关磁阻电动机非线性模型

开关磁阻电动机驱动系统是一个时变、非线性系统 ,若采用通常的建模方法 ,无法获得精确的数学模型。给出了开关磁阻电机变结构模糊神经网络非线性模型 ,基于Takagi Sugeno模糊神经网络 ,提出可变结构的变步长学习算法。仿真结果表明此法比BP神经网络具有更高的精度和更快的收敛速度。     

Calculation of the electromagnetic parameters of a switchedreluctance motor using an improved FEM-BIEM-application to differentmodels for the torque calculation

This paper expands on a hybrid numerical method coupling the finite element method (FEM) and boundary integral equation method (BIEM), developed to calculate magnetic fields in a switched reluctance motor (SRM). This hybrid approach is a solution to the issues stemming from the small size and odd shape of the SRM airgap, where meshing an FEM grid is difficult. In the past, the stator and rotor FEM domains kept their actual shapes, which resulted in problems with the definition of the unit outward normal vector n&oarr; at the corner points of the SRM poles. Therefore, the normal derivative of the magnetic vector potential, i.e., the tangential component of the flux density, was undefined at these points. In this paper, a new approach with new definitions of the stator and rotor FEM domains is presented. The new concept defines the SRM airgap as a ring in which circular boundaries permit the correct definition of the normal derivative quantities and exploit the natural Neumann condition. The electromagnetic parameters of a 7.5 kW SRM prototype machine were calculated using this new approach. They compare favorably with test data. Phase magnetization characteristics also have good precision and smoothness. These electromagnetic parameters were then used to assess and compare two different SRM models for the calculation of the torque on the motor shaft, the linear trapezoidal model and the nonlinear model. The comparison between the measured torque and the torque as calculated with the two different models shows that the more simple trapezoidal model should be satisfactory in many cases and could, in particular, be used in automated SRM designs     

Eliminating starting hesitation for reliable sensorless control ofswitched reluctance motors

Novel methods for rotor position estimation both at standstill and during running conditions are presented for a switched reluctance machine (SRM) starting free of position sensor and hesitation. By applying a DC pulse to the stator phase windings for a short moment (0.5 ms), the initial rotor position can be accurately detected. Combining the accurate initial rotor position with a novel rotor position estimation algorithm during running, the SRM can be started at any initial rotor position without starting hesitation. Critical issues related to optimal model selection as the virtual sensor are discussed in detail. Computer simulation and experimental results are included     

The modeling of switched reluctance machines with magneticallycoupled windings

This paper presents a method of modeling switched reluctance motors with strongly coupled windings, such as switched reluctance machines (SRMs) with fully pitched windings or with commutating windings. These machines are particularly difficult to model because, unlike a conventional SRM, the flux linking any one winding of the machine is a nonlinear function of rotor position and all phase currents. The problem is overcome by breaking down the instantaneous flux linkages and currents in each phase to give the flux and magnetomotive force (MMF) in each tooth of the machine. The flux and MMF per tooth can then be linked in the model by a simple lookup table, determined from either simulation or measurement. The paper describes the simulation method in detail and then gives extensive comparisons between measurement and simulation results for an SRM with fully pitched windings, operating over a range of operating conditions. The results presented also serve to give an insight into the method of operation of these rather complex machines     

开关磁阻电机相绕组匝数对性能影响的分析与设计

分析开关磁阻电机相绕缓刑 由数对电机性能的影响,并对开关磁阻电机进行了仿真计算。在理论分析与仿真的基础上提出了新的开关磁阻电机相绕组匝数的设计方法,以此方法设计了一台８／６结构ＩＫＷ开关磁阻电机,经试验达到了较好的性能。     

基于Maxwell 2D的开关磁阻电动机的仿真研究

基于Maxwell 2D的仿真环境，建立了开关磁阻电动机（SRM）的系统仿真模型，对开关磁阻电动机的基本特性进行了仿真研究。仿真结果可以用于指导这种新型电机及其控制系统的设计和优化。     

新型永磁式开关磁阻电动机电磁场的二维有限元分析

采用二维有了元模型对新型永磁式开关磁阻电动机的电磁场了分析。     

基于支持向量机的中长期电力负荷组合预测

影响中长期负荷的因素多,随机性强,单一预测方法很难满足不同情况的预测需要,组合预测能较好地解决单一模型的不足,但现有组合预测模型主要基于经验风险最小,预测精度受组合模型的限制.本文提出一种基于最小二乘支持向量机的中长期负荷组合预测模型,该模型利用结构风险最小化原则代替传统的经验风险最小化,充分挖掘原始数据和单一预测模型的信息,以单一模型的预测数据作为组合预测样本,选择多项式核函数的最小二乘支持向量机进行组合预测.实际算例表明,本文提出的组合模型预测平均误差仅为1.719%,具有良好的可行性和有效性.     

基于支持向量机的电价组合预测模型

对传统的2个线性组合预测模型进行了分析,提出了一个新的线性组合预测模型,该模型不要求权系数和为1,而且权重也可以取负值。同时,为提高精度,提出了支持向量机非线性的组合预测模型,该模型实质上是一个非线性回归模型,利用结构风险最小化原则代替传统的经验风险最小化。该模型充分挖掘原始数据和单一预测模型的信息,以单一模型的预测数据作为组合预测样本,选择径向基核函数的支持向量机进行组合预测。同时给出了解决此问题的基于Matlab的支持向量机工具箱的源程序。以美国加州电力日均价为例,与单一预测方法、线性组合预测进行对比,支持向量机非线性的组合预测方法预测比较精确。     

Novel Two-Phase Switched Reluctance Machine Using Common-Pole E-Core Structure: Concept, Analysis, and Experimental Verification

A novel two-phase switched reluctance machine (SRM) with a stator composed of E-core structure having minimum stator core iron is proposed. The E-core stator has three poles with two poles at the ends having windings and a center pole containing no copper windings. The center stator pole in the E-core is shared by both phases during operation. The air gap around the common stator pole has constant and minimum reluctance irrespective of rotor position by its unique design, and the two remaining stator poles at the ends experience variable reluctance with respect to rotor position. The stator is constructed with two independent and physically separate E-cores, and the rotor is composed of ten poles. Other pole combinations are possible. Phase excitation in the novel SRM gives short flux paths, hence reducing the magnetomotive force required to drive the machine, resulting in significant reduction of copper wire and core losses compared to existing two-phase SRMs with flux paths that traverse the entire stator back iron. The concept and principle of operation of this novel SRM and its comparison to existing two-phase SRMs are detailed in this paper. Comparison between finite-element simulations and magnetic equivalent circuit (MEC) analysis for inductance are made and compared to experimentally measured characteristics. Furthermore, comparisons between a conventional two-phase SRM and the novel SRM are made in terms of its weight and output torque. Manufacturability and cost savings of the unique SRM structure are presented. It is shown that the E-core SRM using common stator pole has 50% less iron in the magnetic path compared to a conventional two-phase SRM.      

基于Ansoft Maxwell 2D的开关磁阻电机仿真研究

基于Ansoft Maxwell 2D的仿真环境，建立了开关磁阻电动机（SRM）的系统仿真模型。在建立仿真模型基础上，对电动机的基本特性进行了仿真研究，获得了电机不同位置时的磁场分布、静态电磁参数和动态性能仿真结果。仿真结果可以用于指导该型电机及其控制系统的设计和优化。     

Test Results of an SRM Made From a Layered Block of Heat-Treated Amorphous Alloys

In order to produce high-efficiency motors at relatively low production costs, a layered block is made from amorphous iron sheets. From the block, stator and rotor cores of a test switched reluctance motor (SRM) are fabricated. The experimental results of the test machine are compared to another test machine made from low iron loss silicon steel type 35A300 in JIS standard. This silicon steel is equivalent to M-22, 300, and V300-35A in ANSI, BS601, and DIN46400, respectively. The validity of the test results is compared and verified through use of an analytical simulation software package. Approximately 6% improvement in efficiency is observed for the prototype SRM with the layered amorphous core material. The SRM test motor has an efficiency of 95.1% at a speed of 8500 r/min with an output of 2.4 kW.     

基于磁链分析模型的开关磁阻电动机数字仿真

提出基于磁链的开关磁阻电动机(SRM)分析模型。该模型仅仅需要电机几何尺寸和材料电磁参数,不需要实验测量数据或者有限元分析数据,为计算机辅助设计、仿真分析以及预测电机性能提供了分析模型。该模型通过Matlab/simulink来实现。其仿真结果与有限元分析软件Ansoft分析结果吻合。该文将上述分析模型应用于1台550W 6/4极三相开关磁阻电动机的非线性仿真研究中。仿真结果反映了SR电机实际工作特性,有限元分析结果验证了该分析模型的可应用性。     

新型永磁式开关磁阻电机研究

本文介绍一种带永久磁钢的新型开关磁阻电动机。