交-交变频矢量控制系统在热连轧工艺中的应用

主要介绍了交-交变频全数字矢量控制系统的构成和控制原理以及在热连轧主传动中的应用.交-交变频全数字矢量控制系统作为交流调速系统的一种,被广泛的应用到主传动控制系统中.交-交变频调速系统并将随着时代的发展不断完善,逐步取代直流调速系统,成为电气传动领域中的主流.     

交-交变频器矢量控制技术在中板主轧机上的应用

介绍交-交变频器矢量控制技术在邯钢中板主轧机上的应用,系统由7 000 kw同步电动机、交-交变频柜、全数字向量无环流控制装置等组成.重点阐述了交-交变频器在实际应用中的系统构成和控制原理.为消除系统运行中产生的谐波电流及无功冲击负荷,在35 kV母线上安装TCR型动态无功补偿装置.从技术性、经济性、可靠性综合评价直流传动及交-交变频传动的效果.结果表明,后者性能优越.     

热带轧机主传动交-交变频与交-直-交变频调速系统的技术经济比较

以某工程热带轧机为例，对热带轧机主传动调速系统采用交-交变频调速和交-直一交变频调速的优缺点进行比较，总结出交-直-交变频调速系统将是今后热连轧机主传动变频调速系统的发展方向。     

热连轧厂粗轧机交—交变频控制系统

本文叙述了矢量型交-交变频控制的基本原理，并通过新旧系统的对比，介绍了热连轧厂粗轧机交-交变频控制系统及其使用效果。     

宽厚板轧机交-交变频器磁通计算方法研究

文章针对包钢宽厚板轧机主传动交-交变频调速系统,对SIEMENS交-交变频器磁通计算及控制方法进行了研究,计算方法简单,优化了磁通的计算,改善了系统的运行性能,提高了主传动系统生产运行安全稳定性,应用效果良好。     

包钢宽厚板交-交变频器电流调节器计算分析

文章针对包钢宽厚板轧机主传动交-交变频调速系统,对SIEMENS交-交变频器直流电流调节器计算方法进行了研究,计算方法简单,优化了调节器的计算,改善了系统的运行性能,提高了主传动系统生产运行安全稳定性,应用效果良好。     

八钢中厚板轧机交—交变频主传动控制系统的特点

介绍了八钢3500 mm中厚板生产线的精轧机主电机交—交变频传动控制系统,其中包括交—交变频主回路的结构、西门子SIMADYN-D全数字64矢量控制交—交变频控制系统及其在中厚板轧机上的控制功能。     

同步机交-交变频装置在轧机主传动上的应用及调试技术

论述同步电动机交-交变频装置按磁场定向矢量控制原理、UMO、IMO以及混合控制原理，西门子公司SIMADYN-D调速系统、硬件和主要软件模块结构，调速系统优化调试方法，以及它们在珠钢CSP生产线热连轧机主传动中的应用。     

基于PSIM双馈电机交-交变频矢量控制系统的仿真研究

在分析双馈电机数学模型的基础上,基于PSIM6.0软件建立了交-交变频矢量控制系统仿真模型.采用定子磁链定向矢量控制,定子有功和无功分量实现解耦;双闭环控制以转速和定子无功控制为外环,以转子电流控制为内环.电机在亚同步至超同步速的较大范围内平滑调速,定子侧功率因数可调.     

近代交流调速：第六讲 交—交变频器

一、工作原理 交-交变频器没有中间直流环节,可以直接将定频定压的交流电通过电力交流器变换成变频变压的交流电,用以向负载提供变频电源。故又称之谓直接式变频器,也称为循环交流器或周波变流器。     

转炉炉壳热应力分析

根据实际转炉建立实体模型。以有限元为手段,考虑了炉衬和炉壳材料的物性参数随温度变化的特点和炉衬与炉壳之间膨胀间隙,计算了转炉炉壳在温度载荷和炉衬膨胀压力同时作用下的热应力。所得结果可为转炉炉壳设计提供依据。     

焦炭热性能指标意义浅析

通过对焦炭在高炉内的历程及其变化规律的剖析,阐述焦炭热性能指标的意义,形象地把焦炭在高炉内的损耗分为三部分(M1,M2,M3)。指出M2对焦比及焦炭价格有一定的指导作用。     

Results of treatment of cancer of the cardia

Cancer of the cardia is traditionally discussed with cardiac cancer of the lower portion of the esophagus and upper gastric cancer invading the esophagus, and the specific characteristics of cancer of the cardia have never been clearly defined. We reviewed the outcome of 172 patients with adenocarcinoma of the cardia who had undergone radical surgery between 1949 and 1994 in the Division of Gastrointestinal Surgery of the Cancer Institute Hospital. The centers of the tumors were located within 2 cm above and below the boundary between the esophagus and the stomach, and their longitudinal diameter was less than 8 cm. We divided the patients into an early period (1949-1979; n = 79) and a late period (1980-1994; n = 93), and focused on the historical transition. There were no differences in patient gender or histology between the two periods. However, the late period was associated with fewer cases of esophageal invasion and shorter longitudinal diameter, as the age of the population advanced. The number of advanced cancers such as the localized and infiltrative type had decreased, and early cancer and early clinical stage had become more common, but despite the fact that the number of early cancers had increased, extended dissection, such as thoracic and paraaortic lymph node dissection, was performed more frequently. By clinical stage, the long-term outcome markedly improved in Stage I patient in the late period, and tended to improve in Stage II and III patients. This appears to have been attributable to the prevention of micrometastasis by extended dissection, although the number of early cancers is another major potential cause. There were no differences in the outcome of Stage IV patients between the two periods, and further advances in multimodality therapy must be awaited. The range of resection is basically proximal gastrectomy, and if there are adequate indications, the prognosis is favorable. In view of the status of lymphatic flow and lymph node metastasis, and long-term results, lateroaortic lymph node dissection is important. Since the number of early cancer patients has been increasing, if intraabdominal recurrence is prevented, intrathoracic lymph node dissection will contribute greatly to the outcome of such patients.     

Effect of antibiotics of chemotaxis of human leukocytes

The effect of 20 different antibiotics on chemotaxis by human neutrophils was studied. Human leukocytes incubated with chloramphenicol, rifampin, sodium fusidate, and tetracyclines in vitro showed markedly depressed migration. The mechanisms by which these antibiotics affect leukotaxis are discussed.     

Quality of life of relatives of mental patients

Usage of quality of life of psychiatric patients' relatives as the parameter of estimation of the quality of psychiatric care is considered. By means of standard questionnaire elaborated by the authors as well as by means of both individual and group conversations the quality of life was analyzed in 40 relatives which lived together with psychiatric patients. Different spheres of their life and difficulties (financial, social-psychologic, production) were examined in families with such patients. The defects of psychiatric care that had direct influence on the quality of life of the psychiatric patients' relatives are outlined.     

The effect of amount of possession of the trait of hostility on accuracy of perception of hostility in others.

Some theories of personality hold that an individual's perception of others is influenced by his own personality characteristics; more specifically, that a trait of low social value will be projected more into others, and that insight into the possession of these characteristics reduces this distortion. These 2 hypotheses were tested by having a group of college students rate each other (including themselves) on degree of friendliness or hostility. Agreement with group rating about self yielded the insight score. In general, the hypotheses were supported; the "friendly" Ss were most accurate in their perception of others, and insight was positively associated with accurate perception. From Psyc Abstracts 36:04:4HL16M. (PsycINFO Database Record (c) 2010 APA, all rights reserved)