2D Finite Element Analysis of Asynchronous Machine Influenced Under Power Quality Perturbations

Asynchronous machines are predominantly preferred in industrial sectors for its reliability.Power quality perturbations have a greater impact on industries;among the different power quality events,voltage fluctuations are the most common and that may cause adverse effect on machine’s operation since they are longer enduring.The article discusses a numerical technique for evaluating asynchronous motors while taking into account magnetic saturation,losses,leakage flux,and voltage drop.A 2D linear analysis involving a multi-slice time stepping finite element model is used to predict the end effects.As an outcome,the magnetic saturation and losses are estimated using amodified 2D nonlinear time-stepping finite element formulation.The method takes the electromagnetic fields at the ends of the motor into account using limited computer resources.The proposed method will greatly reduce computation timewith limited computer resources for analyzing themachine’s performance with high precision.The analyzed findings assist in preventing voltage variance issues in the power network system and provide suggestions for developing a robust system.

Comprehensive Energy-Saving Optimization Model of Asynchronous Motor for Voltage Regulation Based on Static Synchronous Compensator

There are several problems existing in the direct starting of asynchronous motor such as large starting current,reactive power absorption from network side and weak interference-resistance,etc.Aiming at this,a comprehensive energy-saving optimization model of asynchronous motor for voltage regulation based on static synchronous compensator(STATCOM)is put forward.By analyzing the working principle and operation performance of static synchronous compensator regulating voltage,a new energy-efficient optimization method for asynchronous motor is proposed based on the voltage regulator model to achieve soft start,continuous dynamic reactive power compensation and the terminal voltage stability control.The multi-objective optimal operation of asynchronous motor is realized by controlling the inverter to adjust the reactive current dynamically.The strategy reduces the influence of starting current and grid voltage by soft starting,and realizes the function of reactive power compensation and terminal voltage stabilization.The effectiveness and superiority of the proposed model is verified by the simulation analysis and the results of comparison with the motor started directly.

Research on and Design of Mechanical System with Optimal Cutting Movement Trajectory of Energy-Saving Stone-Sawing Machine

The technique of cutting slabstone with stone-sawi ng machine is analyzed completely. A new kind of cutting movement trajectory is gi ven whose actual cutting efficiency is near to 100%. It can reduce the energy w earing greatly, and the surface quality of the product is improved to the utmost extent. The design mechanism of the optimal cutting movement trajectory system structure is analyzed incisively. At the same time, the principle of the complex movement of horizontal movement and swing is researched. The optimal design scheme of th e cutting movement trajectory system structure is set up. The choice method to g et the superior value of the movement system structure is found. The mathematics function formula is established which exhibits the relationship between the par ameter of the complex movement structure and that of the system movement structu re. By the formula, the precision value of the offset can be figured out. The r ule is adapted to different types of energy-saving stone-sawing machines. The complex movement structure of horizontal movement and swing is designed to f ulfill the cutting movement. It can make the saw frame move up with the hanging pod deviating from the vertical direction. At the same time, the saw frame have a down-movement. Then the sum of the two movements is near to zero, and the saw blade and the stone can keep in touch during the whole horizontal cutting. The result is that the actual cutting efficiency is 100%. Also, when the hanging pod moves to the limited position, the saw frame can keep the original inertia, and continue to swing up. It makes the back-cutting have high energy-storing. The optimal design of the eccentricity balance wheel is done. The mathematics fo rmula for expressing the movement system structure is deduced. The calculation m ethod and formula is set up which is used to get the value of important componen ts such as offset. The choice method and formula of elasticity distortion coeffi cient is set up when the saw frame moves smoothly. It is concluded that the offs et is the key dimension to actualize the optimal cutting movement trajectory. The resolving of the technical problems discussed above offers a theoretic and technical basis for optimal design of energy-saving stone-sawing machines.

A study of novel real-time power balance strategy with virtual asynchronous machine control for regional integrated electric-thermal energy systems

The development of regional integrated electric-thermal energy systems(RIETES) is considered a promising direction for modern energy supply systems. These systems provide a significant potential to enhance the comprehensive utilization and efficient management of energy resources. Therein, the real-time power balance between supply and demand has emerged as one pressing concern for system stability operation. However, current methods focus more on minute-level and hour-level power optimal scheduling methods applied in RIETES. To achieve real-time power balance, this paper proposes one virtual asynchronous machine(VAM) control using heat with large inertia and electricity with fast response speed. First, the coupling timescale model is developed that considers the dynamic response time scales of both electric and thermal energy systems. Second, a real-time power balance strategy based on VAM control can be adopted to the load power variation and enhance the dynamic frequency response. Then, an adaptive inertia control method based on temperature variation is proposed, and the unified expression is further established. In addition, the small-signal stability of the proposed control strategy is validated. Finally, the effectiveness of this control strategy is confirmed through MATLAB/Simulink and HIL(Hardware-in-the-Loop) experiments.

基于特征集重构与多标签分类模型的谐波源定位方法

传统基于谐波状态估计的谐波源定位方法需要专门的同步相量量测装置,工程应用受到限制。为此,基于电能质量监测装置所采集的非同步量测数据,提出了基于特征集重构与多标签分类模型的谐波源定位方法。利用监测数据的充分统计量来挖掘量测时段的谐波信息,同时利用标签特定特征学习算法重构特征集,从而消除冗余特征以及无关特征对于谐波源定位精度的影响;提出基于邻接矩阵以及灵敏度分析的测点配置方法,结合电路网络拓扑信息实现测点的优化配置;提出基于改进极限学习机的谐波源定位方法,该方法以重构特征集为输入,建立多标签分类模型,实现谐波源定位。通过仿真与算例分析,验证了所提方法的可行性及有效性。

智能化视角下造纸机传动系统变频调速控制研究

在当今造纸行业向智能化转型的背景下,造纸机作为纸张生产的核心设备,其传动系统的高效运行对整体生产效率和产品质量起着决定性作用。电气自动化与变频调速技术的深入应用,极大地推动了造纸机控制系统的技术进步,为实现造纸机械高效、稳定生产提供了坚实的技术基础。基于此,在探讨造纸机传动控制系统的构成与设计关键点,并针对常见的变频调速技术进行分析,特别是直接转矩控制(DTC)算法在优化传动系统中减少异步电机电磁转矩波动、降低能耗、提升效率方面的应用,旨在为造纸机传动系统的优化提供切实可行的解决方案。

异步机定子磁势磁密关系研究

提出了磁势导密法,并据此论证了基波磁势能够同时产生基波磁密和谐波磁密;谐波磁势可能同时产生谐波磁密和基波磁密。

基于转子铜耗的异步机运行状态分类

提出一个关于异步机运行状态的新的分类方法:转子铜耗法。按此法,异步机运行状态可分为两个:差能态、和能态。差能态包含电动、发电两个态;和能态对应电制态。转子铜耗分类法对学习和巩固异步机制动知识点尤其有帮助。

计及源荷惯量特征的电力系统最小惯量需求评估

新型电力系统弱惯量特性所带来的频率安全问题,本质是系统等效惯量的减少。因此,量化评估新型电力系统最小惯量需求成为亟须解决的工程问题。为此,提出了最小惯量需求评估方法。首先,建立了考虑火电机组、风电机组、异步电机参与调频的多机系统空间频率响应(SFR)模型,并在量化分析系统频率特征的基础上,考虑风电机组、异步电机的虚拟惯量特征,建立了电力系统等效惯量数学模型。接着,以初始频率变化率(RoCoF)、最大频率偏差为频率安全约束,并基于频率响应模型对电力系统最小惯量需求进行评估。最后,在MATLAB/Simulink和PSD/BPA仿真平台上验证了所提方法的有效性。

基于可视化需求的分段传动造纸机电气传动监控系统研究

分段传动造纸机是一种在传统直线轴传统运动控制策略基础上改进而来的分阶段传动的新型造纸机。为对分段传动造纸机电气传动系统工作情况、运行状态等进行良好监控,开发了一种基于物联网、可视化技术的监控系统,针对该系统在分段传动造纸机电气传动模块工作时的监控效果进行分析。结果表明:这一监控系统可以直观、有效地对分段传动造纸机电气传动模块的运行状态进行监控,极大地方便了操作人员对电气传动模块的运行管理。

Tolerating Permanent State Transition Faults in Asynchronous Sequential Machines

Corrective control theory lays a novel foundation for the fault-tolerant control of asynchronous sequential machines. In this paper, we present a corrective control scheme for tolerating permanent state transition faults in the dynamics of asynchronous sequential machines. By a fault occurrence, the asynchronous machine may be stuck at a faulty state, not responding to the external input. We analyze the detectability of the considered faults and present the necessary and sufficient condition for the existence of a controller that overcomes any permanent transition faults. Fault tolerance is realized by using potential reachability and asynchronous mechanisms in the machine. A case study on an asynchronous counter is provided to illustrate the proposed fault detection and tolerance scheme.

模糊熵特征选择与SVM在三相异步电机故障诊断中的应用

三相异步电机故障发生率高,用电量大且故障难以早期识别。基于此,提出一种基于模糊熵特征选择和支持向量机(Support Vector Machine,SVM)的故障诊断方法。通过构造故障再现试验,测取其四种不同状态类别的多测点振动信号样本,采用模糊熵计算其模态分量的模糊熵样本值,得到四种不同状态类别的模糊熵故障特征向量。然后,结合支持向量机算法,构建支持向量机分类模型,划分模糊熵特征量训练样本和测试样本。通过构造的SVM模型训练和验证,验证结果表明故障诊断准确度达到97.5%,利用常用的改进BP神经网络诊断方法进行对比,准确度为92.5%,结果表明基于模糊熵特征选择与SVM方法在诊断精度上更高。

虚拟同步发电机对系统低频振荡的影响及抑制方法综述

为梳理虚拟同步发电机接入后对系统低频振荡的影响,进一步发掘其在提供阻尼和惯量方面的潜力和应用,开展相关梳理和研究工作。首先,归纳和总结电力系统低频振荡的研究现状;然后,对非同步发电机电源并网后对系统低频振荡的影响进行概括和分析;最后,综述伴随非同步发电机电源接入的虚拟同步发电机对系统低频振荡的影响和抑制方法,并针对虚拟同步发电机在新型电力系统应用过程中亟需解决的关键问题提出进一步的思考和展望。

异步机状态的能量观及其对同步发电机不对称短路的启示

从能量(功率)的角度,详尽分析了异步机全部五种状态的特征。特别值得强调的是制动状态的特征:从定子和转子两个方向汲取功率,用于转子绕组的铜耗。该铜耗转化为热能,导致转子绕组过热,甚至被烧毁。从中得到对同步发电机不对称短路的启示:负序猛于虎,千万要当心。

基于轻量化级联网络破竹机竹径测量

针对现有自动破竹机测径方法通用性不强,且难以同时测量厚度的问题,采用YOLOv4-Tiny和MobileNet-SegNet组成级联网络,利用双目视觉进行测距,用最小外接圆获取外径与厚度,构建测量算法。测量系统以USB双目摄像头作为成像设备连接树莓派4B和Movidius神经计算棒,用Python编写主程序,并用OpenVINO异步模式部署模型。以不同距离、角度、竹筒规格展开测量试验。结果表明,算法最优测量距离是30~40 cm,竹筒外径测量平均相对误差为1.43%,厚度测量平均相对误差为8.76%,检测速度为7.1 FPS。本研究可为自动破竹机测径换刀系统设计提供依据。

交流电机VF控制与矢量控制的比较

电机是目前最主要的耗能设备,据了解世界上大概60%的电能都是电机消耗的,而电机调速性能的好坏决定了电机性能的好坏,所以调速成为了人们一直关注并不断研究改进的话题。该文对交流电机的两种常见调速方法做对比分析,分别分析了目前技术成熟且应用普遍的VF调速控制法、由德国学者HASSK和BLASCHKEF提出的矢量控制理论,并对二者的优点与不足做了详细的比较;最后分析了两种方法在控制原理与实现过程中的利弊。

基于APSO-SSVM的异步电动机转子故障诊断

基于信号分析的异步电动机的转子断条与偏心故障诊断方法中,常用传统的电机电流信号特征分析(MCSA)方法。由于采样频率偏低、强大的基波旁瓣效应等因素的影响,会导致特征频率成分被淹没、难以量化故障程度等问题。因此,提出了一种基于自适应粒子群优化逐序支持向量机(APSO-SSVM)的异步电动机故障诊断方法。首先,利用经验小波变换(EWT)对原始信号进行滤波;然后,对滤波后的信号进行特征提取并输入到SSVM诊断模型中;最后,通过APSO算法确定各次序下SVM模型的最佳超参数,从而实现转子断条数量的精确故障诊断。

同步磁阻电动机研究

该文根据能量平衡观点,以异步电动机为参照,较全面地分析了Xd、Xq和凸极比K对磁阻电动机性能的影响,讨论了凸极比适合值的选择问题,并指出对cosj小于0.85以下的小容量电机,同步磁阻电动机在应用中可与异步电动机匹敌。

基于MATLAB的异步电机软起动过程的仿真

该文采用Matlab/Simulink软件系统及其电气系统模块库 (PowerSystemBlockset) ,对异步电机软起动的仿真进行了研究 ,阐述了软起动主要环节模块的处理 ,建立了完整的仿真系统模型 ,最后给出仿真结果 。