Temperature Rise Analysis of Switched Reluctance Motors Due to Electromagnetic Losses

We present a finite-element analysis of the temperature rise of switched reluctance motors (SRM) due to electromagnetic losses. We estimate the various components of electromagnetic losses, including core loss in the lamination as well as copper and eddy-current losses in windings, and then predict the temperature rise within the motor due to these losses. We present simulation results for an 8/6 SRM and discuss various aspects of thermal design of SRMs. To validate the procedure for the estimation of electromagnetic losses, we compare predicted and measured losses.      

Diagnosis of Static Eccentricity in Switched Reluctance Motors Based on Mutually Induced Voltages

This paper presents a novel method for diagnosis of eccentricity in a switched reluctance motor (SRM). The method employs two-dimensional finite-element analysis to calculate mutual fluxes and mutually induced voltages in an 8/6 SRM. An investigation of the effect of static eccentricity on these quantities shows that eccentricity has a considerable effect on them. Since flux measurement is costly, the method introduces mutual voltage as a suitable criterion for diagnosis of eccentricity in SRMs.      

A New Analytical Model for Switched Reluctance Motors

We present a new analytical model for switched reluctance motors (SRMs). The model uses four coefficients, which are rotor position dependent and calculated from the flux-current-angle data using numerical curve fitting with least squares method. The four coefficients are further represented with sixth degree polynomials, which can be calculated effectively with Qin Jiushao's method. Simulated results show that the magnetic characteristics calculated with our model agree well with the original flux-current-angle data. The instantaneous electromagnetic torque derived from the developed model matches well with the numerically calculated torque. Finally, we compare dynamic simulations based on the model with experimental results and find good agreement.      

DSP-Based Automated Error-Reducing Flux-Linkage-Measurement Method for Switched Reluctance Motors

The switched reluctance motor (SRM) has received considerable attention from researchers for its many inherent advantages, and thus, it has become a popular research topic in the field of variable-speed drives as well as servo drives. Research on SRMs mainly includes their design, modeling and performance analysis, control, as well as applications. However, for verification of design, performance prediction, as well as development of a high-performance sensorless control algorithm, accurate measurement of the magnetic characteristics of the SRM is most critical. Hence, one of the most important problems in the field of SRMs is a practical and accurate instrumentation system for the measurement of the SRM magnetic characteristics. This paper first describes an accurate and fully automated digital method for the measurement of the magnetic characteristic of SRMs, which includes online offset-error removal and winding resistance estimation. In this method, a digital-signal-processor-based virtual instrumentation for measurement of flux linkage is developed. Then, the results of the measurement conducted on a four-phase SRM are presented. The accuracy of the measurement system is verified by comparing with that found via a magnetic analyzer. Finally, the various sources of errors and their contributions to the errors are discussed. The scheme can also be used, in general, for transformers or inductors.     

An Analytical Circuit Model of Switched Reluctance Motors

We have developed a dynamic analytical circuit model to simulate the performance of switched reluctance motors (SRMs). Our model expresses flux linkages as multiple decoupled one-argument functions, either current dependent or rotor position dependent, instead of one two-argument function dependent on both current and rotor position. We propose a novel approach for the computation of the air gap permeance at various rotor positions. By using this analytical model, the performance of a SRM can be simulated very efficiently and with improved accuracy. As an application example, we present a simulation of an 8/6 pole SRM in the system domain, and compare the results with transient finite element analysis (FEA) solutions.      

A Novel Flux Linkage Measurement Method for Linear Switched Reluctance Motors

The magnetic characteristics of a linear switched reluctance motor (LSRM) are important in its performance prediction and verification. Owing to the complicated magnetic paths, the measurement of the flux linkage for this type motor has drawn many researchers' attentions. In this paper, a new flux linkage measurement method for LSRMs is proposed to obtain the flux linkage characteristics of LSRMs using an online winding resistance estimation technique. Both the theoretical derivation and the actual implementation of the proposed method are addressed in this paper. In comparison with the search coil scheme and the static resistor scheme, experimental results confirm the validity and accuracy of this method. In short, the proposed method is simple, effective, and easy to be implemented. It is a practical solution for flux linkage measurement of LSRMs and other motors.     

Fast Analytical Determination of Aligned and Unaligned Flux Linkage in Switched Reluctance Motors Based on a Magnetic Circuit Model

The main advantages of the switched reluctance motor are high torque, wide speed range, simple structure and fault tolerance. Because a switched reluctance motor has inherently nonlinear magnetic characteristics and a doubly salient pole structure, a finite-element analysis approach (FEA) is often adopted to obtain accurate magnetic representation. However, the solution time can be large for a FEA simulation if the mesh is detailed and/or many simulations are required. We propose a rapid analytical solution for determining the aligned and unaligned flux linkage using a magnetic circuit model. We present a simple method for obtaining the air-gap permeance for unaligned linkage. The results of our method agree well with FEA solutions.      

Finite-Element Analysis of a Switched Reluctance Motor Under Static Eccentricity Fault

This paper describes a two-dimensional finite-element analysis of an 8/6 switched reluctance motor with static eccentricity. It describes the influence of the eccentricity on the static characteristics of the motor and shows how to obtain flux lines, flux density distribution, and the flux-linkage/rotor angular position characteristic of the motor in both healthy and faulty conditions, as well as the static torque profiles of phases for different degrees of eccentricity. It shows that, at low current, the effect of the eccentricity is considerable compared to that at the rated current. Fourier analysis of the torque profile is used to study the variations of static torque harmonic contents.     

Measurement and Real-Time Modeling of Inductance and Flux Linkage in Switched Reluctance Motors

This paper presents a real-time model to identify the inductance and the flux linkage of switched reluctance motors (SRMs). A dynamic measurement method is used for the real-time modeling. An artificial neural network (ANN), designed in accordance with the inductance and the flux linkage data obtained from the dynamic measurement method, is used to make the real-time model. Experimental studies are realized to prove the applicability of the dynamic measurement method and the ANN-based model. The experiments are performed by using a TMS320F2812 digital signal processor (DSP). The results show that the dynamic measurement method and the ANN-based model ensure real values in all the positions and load conditions of the motor.      

计算橡胶隔振器静态特性的数值分析方法

以橡胶隔振器为研究对象,利用有限元ABAQUS分析软件,进行了橡胶隔振器有限元建模的数值试验分析;为了能更精确的描述橡胶的特性,引用了多年来发展的几种弹性应变能函数方法,选取本构方程来拟合试验数据以作为ABAQUS软件对橡胶材料特性曲线的评估,寻找一种描述橡胶特性的最佳的方法。预测的计算结果与试验吻合较好,表明所建的数学模型和有限元计算方法能较理想的获得橡胶隔振器静态解。     

On Improvement of Methods for Experimental Determination of Strength Characteristics of NPP Component Materials

The methods for experimental determination of strength characteristics as per applicable standards have been reviewed. For some structural steels used in NPP facilities, the influence of loading parameters and specimen geometry are allowed for during the assessment of static fracture toughness (K_Ic, J_Ic). Recommendations are given on the setting of cycling conditions for fracture toughness testing of standard specimens with and without crack-guiding lateral grooves. The authors substantiate the applicability of the Master Curve method to determination of fatigue strength of small specimens with subsequent use of the results for calculating brittle fracture resistance of reactor pressure vessel materials in the welded joint.     

碗式中速磨煤机运行特性试验研究及应用

为提高制粉系统运行的安全性和经济性,对300 MW锅炉碗式中速磨煤机制粉系统进行了优化调整试验。试验研究了碗式中速磨煤机出力特性、磨煤机分离器挡板特性,调整了磨煤机最佳通风量,获得了磨煤机分离器折向挡板刻度与煤粉细度、磨煤电耗、磨碗差压的关系曲线。试验结果表明：随分离器折向挡板刻度的增大,煤粉细度变小,磨碗差压增大,磨煤机电流增加。根据磨煤机特性试验,提出了磨煤机最佳通风量、磨煤机出力及分离器挡板开度控制范围,并依据磨煤机运行情况提出设备缺陷检修建议,优化试验工况的磨煤机单耗下降8.5%,节能效果比较明显。     

车用交流发电机电磁噪声特性的实验研究

针对车用交流发电机在低转速下噪声值偏高并伴有啸叫声的现象,基于实验研究车用交流发电机的噪声特性。首先在发电机上布置转速仪、加速度传感器和传声器,采集发电机在空载及负载状态下振动和噪声的时域信号;其次利用频谱、阶次分析等方法,找出了发电机在负载工况下低转速时噪声峰值的主要阶次成分;最后提出改进措施,对改进后的发电机进行测试,并对比分析改进前后发电机噪声的变化情况。分析结果表明,在低转速下发电机的主要噪声是电磁噪声,该电磁噪声的阶次成分与定子铁芯槽的个数相关,并且提出的改进措施能有效的降低发电机的电磁噪声。     

硅微声光传感特性的实验研究

硅微声光传感器是一种由硅微列阵簧片和光纤组合成的新型传感器，这种传感器在完成声光转换的同时对声频信号进行了并行滤波处理，可用作神经网络的并行输入，是一种光机电一体化的传感系统。本文中叙述通过纤反射强度调制技术检测硅簧片振动信号的方法；通过实验研究，完成了对声光调制信号的探测和预处理，并给出了实测数据及其分析。为实现音频编码和振动信号的实时分析，本文中还给出了采用人工神经网络对阵列传感器的输出信号进     

Modeling of a Switched Reluctance Machine Based on the Invertible Torque Function

This paper presents a switched reluctance machine model based on an invertible expression representing the torque-phase current relationship. The model can be useful for real-time control in high-performance applications when the command current is derived from the torque command. The two angular functions that the model requires as input can easily be calculated from the known static torque-position characteristics for two currents. However, the paper also proposes the analytical models of the angular functions. The result is a geometry-based analytical model, with all parameters derived from machine geometry and material properties. Simulation and experimental results illustrate that the model provides very high accuracy.      

基于峰谷互补方法的开关磁阻电机转矩脉动抑制研究

开关磁阻电机的非线性电磁特性以及脉冲工作方式会产生明显的转矩脉动,针对这一问题,在分析开关磁阻电机转矩脉动产生原因和实际测量转矩脉动波形的基础上,提出了一种基于峰谷互补原理抑制开关磁阻电机转矩脉动的方法.该方法使用2套定转子参数相同的电机系统,使之产生相位互差180°电角度,幅值近似相同的转矩脉动波形,利用峰谷互补原理...     

SVPWM逆变技术在SRG风力发电系统中的应用研究

本文对开关磁阻风力发电系统结构、控制模式进行了简要概述,提出一种基于空间矢量的SVPWM算法,重点研究了SVPWM逆变技术在开关磁阻风力发电系统中的应用,并在MATLAB仿真平台上建立SVPWM逆变模型,验证了该算法的可行性,表明SVPWM逆变技术能在有效减少谐波含量的基础上,得到频率和幅值都比较理想的输出电能.     

Methods for the Determination of the Characteristics of Porous Saturated Media

We analyze the existing methods for the determination of physical constants of porous media saturated with liquids based on static and quasistatic methods of measurements with regard for the initial stresses in the material. On the basis of the experimental data available from the literature, we determine various unknown parameters for typical porous media.     

Static Performance of a Polarized Permanent-Magnet Reluctance Actuator for Internal Combustion Engine Valve Actuation

This paper describes the topology of a permanent-magnet polarized reluctance actuator that enhances the performance of electromagnetic valve actuation systems; specifically, it reduces losses during extended periods of valve closure, improves controllability, provides a degree of fail-safe operation in the event of a system fault, and reduces currents required for system initiation during cold-starting of the engine. The paper describes the basic operating mechanism of the actuator and explains the influence of various design features on its static characteristics by means of a finite-element-based design study on a representative performance specification. A prototype device has been manufactured and its static characteristics have been measured experimentally to illustrate the utility of the proposed actuator topology and the key findings from the design study.     

基于微波的管内气固两相动静特性的实验研究

本文首先根据气固两相流参数测量的特性搭建了气固两相流试验台,其中包括静态微波吸收试验台以及小型垂直气固两相流试验台;并且建立了一套基于虚拟仪器的试验数据采集和处理分析系统.然后,对在静态和动态情况下的微波信号吸收特性进行了试验研究,最后,通过对实验数据的分析,建立了相应的数学模型.