大功率交直交变频器在镍板带轧机系统的应用

针对某集团公司800mm热轧机主要轧制产品为镍及镍合金板带材,要求四辊可逆轧机的主传动系统应具有过载能力强、静态和动态响应特性优良、可靠性高、便于维护等问题,提出了一种由PWM整流器和PWM逆变器一起构成四象限交流调速三电平大功率交-直-交变频传动方案.该系统采用IEGT作为功率器件;采用二极管箝位式三电平PWM整流器和逆变器;传动系统功率单元采用纯水冷却、采用大功率异步电动机.实际应用表明,该系统传动特性响应优异、效率高、节能、具有很高的可靠性.     

基于BP神经网络算法的粉碎机自适应控制系统设计

针对饲料加工行业中锤片式粉碎机控制系统存在启动时间长、响应速度慢及负载变化时出现的稳定性差等问题,提出了一种基于BP神经网络算法PID控制方法。首先,建立变频器和饲料粉碎机驱动电机组合系统传递函数的参考模型,并对其进行稳定性分析。然后在分析常规PID和模糊PID控制算法的基础上,将自适应神经网络算法PID应用到饲料粉碎机驱动系统的控制过程当中。通过搭建饲料粉碎机控制电机的仿真模型,利用MATLAB软件中的Simulink图形化编程功能对其进行仿真分析,并基于LABVIEW软件搭建了粉碎机测控系统试验平台进行实验测试分析。结果表明：对于饲料粉碎系统所给定的速度参考模型,设计的BP神经网络PID控制器能够实现较好的自适应追踪,对阶跃信号的响应更加迅速、超调更小,抗干扰能力更强。设计的自适应控制器能够根据工况变化自动调节PID参数,吨料电耗平均降低5.16%、生产率平均提高2.08%,对粉碎机主轴转速的控制更加精确,误差更小,兼具了较高的控制精度和较强的鲁棒性,满足饲料粉碎机驱动系统的自适应控制要求。     

Analysis and Verification of Design Concepts for a 7000-hp Ring Gear Driven Mill?Part I

The choice of one 7000-hp (5220-kW) finish grinding mill versus two smaller units for the Martin Marietta Cement plant in Davenport, IA is discussed. Design considerations of the mill-drive system are covered, with emphasis on the composite mechanical- electrical drive and the need to avoid damaging torsional frequency conditions in it. The mathematical torsional analysis of the mill-drive system is presented, and conclusions of that design activity are given.     

轧钢机辊道的低频传动及低频电源装置

介绍一种用于轧钢机辊道低速传动的交交变频式低频电源装置的工作原理、用单片机构成的控制器及其外围电路以及控制软件的组成。     

大型H型钢生产线轧机主传动系统选型

交-交变频传动系统和交-直-交变频传动系统在轧钢生产领域的应用较为广泛,以大型H型钢生产线轧机主传动选型为基础对两种系统进行了研究.通过对比两种传动方式在系统结构、工作原理、性能指标等方面的不同,确定了系统应用的方向.大型H型钢主传动系统依据这些研究数据进行了选型并成功地在生产线上进行了应用.     

预见PWM控制在轧机调速系统中的应用

首先介绍了单传动轧机主传动调速系统的硬件结构,然后阐述了最优预见PWM控制原理及其工程应用。预见PWM控制新技术在轧机主传动调速系统中的成功应用解决了在采用PWM技术载波频率较低的情况下波形失真较高的问题,消除了脉动转矩,提高了控制精度,延长了功率开关器件的使用寿命。实践证实了这一新技术的有效性。     

Electrical Equipment for a High-Speed Aluminum Rolling Mill

The electrical equipment and systems for a specific aluminum cold rolling mill for attaining rolling speeds in access of 8000 ft/min are described. New systems applications in automatic guage control, main drive systems control, automatic mill preset functions, automatic sequencing, and positioning systems are also presented.     

Selection criteria for SAG mill drive systems

The various options available for large-horsepower semiautogenous grinding (SAG) mill drive systems are examined, together with their impacts on mill design and relative capital and operational costs. A brief history of large-mill drive systems is given. State-of-the-art mill design and mechanical design considerations are also discussed. A design for fixed-speed or variable-speed operation is presented, and the capital and operational cost factors that influence design are considered. The choice of a drive system is independent on the size of the mill, its critical speed, and the horsepower required. Several areas of concern are outlined for each drive-system design. A criterion for selecting the best design for large mills is developed     

Large Grinding Mill Drives Update

The trend to larger grinding mills with the attendant increase in motor drive horsepower has affected the options for drive equipment. Also the development of large adjustable speed drives has created new possibilities for mill drives. Grinding mill torque characteristics, drive requirements, and torsional excitations of the various types of available drives will be briefly reviewed.     

大型交交变频轧钢电动机扭振问题的研究

近年来,我国两台引进的交交变频电动机驱动的1150初轧机主传动系统出现的恶性事故引起了人们的关注。本文根据对实测结果的分析,发现电磁力矩中确有与机械系统固有频率相同的成分,但它不足以导致设备发生事故,而轧制过程中打滑引起的发散振动则是最危险的因素。     

Replacement drive system installation

In this article, the author explores existing conditions that necessitated action beyond normal mill maintenance. Difficult operating conditions and negative effects on mill productivity were identified. This article reports options and decisions encountered prior to and during installation and initial operation of the AC drive. The drive system has been modified to increase machine speed capability. Difficult operating conditions and negative effects on mill productivity were identified.     

Evaluation of mill drive options

Mill drives in the cement industry cover a wide range of mechanical drive and motor applications. This paper includes an overview of the various mill drive options with an emphasis on single motor drives. A more detailed review of the most recent drive development, the compact drive, is featured. In addition, a case study of a mill application is presented to show the effects on voltage drop. The paper concludes with comparative costs on the various combinations of drives and motors     

15000-HP gearless ball mill drive in cement-why not!

Over recent years, there has been a clear trend toward higher capacity cement production units. Five to ten years ago 2500 tons per day was large. Nowadays in Asia, lines are built for 10000 tons per day. The development of ball mill grinding units has not shown the same trend; output and ratings have remained more or less constant perhaps due to the success of pregrinding with high pressure grinding roll technology. This lack of movement toward larger mills is somewhat surprising since in the same period the drive rating of ball mills for similar duties such as ore grinding has shown an increase in drive ratings from 3000-15000 hp. Ball mills in this power range are equally, when not more, efficient than their smaller counterparts and are capable of processing the total daily production within the overnight low-tariff period for electrical energy. Significant energy and cost economies can be achieved with a gearless mill drive working with a ball mill in these upper power ranges. This prospect should also be of interest to the cement industry. The technology is available for an up-sizing of cement grinding installations and the gearless mill drive is a proven, reliable drive     

An electrical feed drive-control system for a cold reducing mill

Methods of control synthesis with the selection of parameters of the electrical-power equipment of a cold reducing mill using the example of the Chelyabinsk Pipe-Rolling Plant have been proposed. The proposed methods of a multiconnected system based on the minimum-error criterion for positioning of a movable element, and it is different in that the selection of the control structure is determined by the frequency ratio of the contour cutoff “unchangeable part” of the electric drive and electromagnetic-torque control loop. The task of control synthesis was divided into three stages. The first stage is the search for the optimal curve of movable-element variable speed based on the criterion of minimum electric losses. The second stage is parametric optimization of the electric-power-system parameters. Finally, the third stage is selection of the structure and parameters of the control-system corrective links. Control measures in systems with subordinate regulation and modal control with a change of the frequency ratio of the contour cutoff “unchangeable part” of the system and torque control were compared during research. The developed control-synthesis methods for the positioning electric drive may be recommended for any technological facilities of steel production in which an electric drive provides motion for a movable element with a high level of accuracy.     

具有不确定性参数的轧机主传动系统自抗扰控制器设计

轧机主传动系统通常由直流电机驱动,其性能好坏直接影响板带材的产量和质量.针对轧机主传动系统存在不确定性负荷扰动和未建模动态的特点,首先建立了轧机主传动系统的模型,将不确定性负荷扰动和未建模动态视为一个综合扰动项,然后利用扩张状态观测器对综合扰动项进行观测和补偿,基于自抗扰控制技术设计了一个不依赖于对象模型的轧机速度鲁棒控制器.仿真结果表明:该控制器不仅有效地抑制了不确定负荷扰动的影响,同时对系统内部参数如电机转动惯量、电枢电阻等的摄动也具有较强的鲁棒性.     

Rotary Grinding Mill and Drive Motor Torque Relationships

An understanding of torque relationships in the operation of rotary grinding mills necessitates a complete analysis of the mill, gear train, and drive motor insofar as torsional load, inertia, and frictional losses are concerned. Ability of a drive motor to develop the required torque is dependent upon its inherent torque characteristics in combination with its electrical supply system. A complete evaluation of both the drive motor and power system is therefore necessary to assure that proper torque will be supplied by the drive motor for the mill requirements.     

12相整流系统在初轧机的应用

介绍了应用在直流初轧机上12相整流系统的结构。2台西门子6RA70装置组成主从控制系统,其中一个装置作为主系统,实现速度、电流双闭环控制和励磁控制;另一个装置作为从系统,接受主系统发出的电流设定指令,工作在电流调节方式。6RA70装置之间通过点对点协议实现主从控制和励磁控制。同时介绍调试步骤。该系统已用于850初轧机传动,并取得良好的效果。     

The Hot Strip Mill Looper System

In the modern hot strip mill, the loopers establish a low and relatively constant level of tension between stands. This aids in minimizing width deviation, and provides an isolated environment for the operation of automatic gage control equipment at each stand. The looper also serves to keep all stands of a mill in synchronism during speedup and slowdown when metal is in the mill. The flexibility of control which is inherent in adjustable-voltage looper systems permits the incorporation of a number of features which contribute to the effectiveness of the drive. Static and dynamic characteristics of electric hot strip mill looper systems are reviewed.     

Compensation of a digitally controlled static power converter forthe damping of rolling mill torsional vibration

A significant advance in damping of torsional vibration by the application of an additional control loop is described. The control feeds measured spindle torque into the drive current regulator, typically increasing damping by 50 to 100%, which is comparable with other damping methods reviewed. A scale model and a large full-scale mill have both been tested with the new control loop. The increased damping is required as a result of efforts to increase rolling mill production through higher speeds and bite angles, with a consequent increase in the incidence of resonant torsional vibration problems such as shudder or chatter. A large reduction in motor speed drop and recovery time is an additional benefit. Tuning of the motor speed and current regulators can be of some help in improving the damping of the drive system; however, the speed-sensor ripple and sampling delays of the digital speed regulator limit the scope for improvement     

ZGM113G型中速辊式磨煤机传动盘密封系统改造

内蒙古京隆发电有限责任公司ZGM113G型中速辊式磨煤机随着运行时间的增加,传动盘碳精密封环部位频繁出现漏风、漏粉等现象,影响磨煤机的安全运行。对磨煤机传动盘内、外部密封进行改造:在传动盘内部加装金属密封护套,将传动盘外部的碳精密封环更换为橡胶密封环。通过改造,彻底解决了传动盘密封环频繁泄漏等问题,不仅节约了维护费用,提高了磨煤机运行的安全性,减少了维护工作量,而且提高了现场文明生产水平。改造经验可为使用同类型磨煤机的电厂提供借鉴。