倍加器型高频高压数字电源

为了精确控制不同的工作环境下静电除尘器的电压,讨论了传统静电除尘用低频高压电源与高频高压电源的区别,用PSpice软件仿真了静电除尘器用高频高压电源。分析了频率对倍加器输出电压的影响;利用仿真结果拟合出高压硅堆导通时间公式,可用于高压硅堆损耗计算及高压硅堆型号的选择;利用公式推导出负载对输出功率的影响。最后给出基于LabVIEW环境的倍加器型高频高压电源实验,验证其频率、输出的可控性;通过电压反馈控制,将杂散电容引起的不稳定频率上限从<5kHz提高到>10kHz,降低了电源所需高压电容的大小,降低了系统成本。     

电除尘器振打中的问题及对策

分析了影响电除尘器振打效果的因素,为改善振打效果,提出了在振打装置机构设计、维修、运行中可采取的措施,为从事电除尘器工作的人员提供参考。     

Experimental modeling of high-voltage corona discharge using design of experiments

Many studies, both experimental and numerical, were devoted to the electric current of corona discharge and some mathematical models were proposed to express it. As it depends on several parameters, it is difficult to find a theoretical or an experimental formula, which considers all the factors. So we opted for the methodology of experimental designs, also called Tagushi’s methodology, which represents a powerful tool generally employed when the process has many factors to consider. The objective of this paper is to model current using this experimental methodology. The factors considered were geometrical factors (interelectrode interval, surface of the grounded plane electrode, curvature radius of the point electrode), climatic factors (temperature and relative humidity), and applied high voltage. Results of experiments made it possible to obtain mathematical models and to analyse the interactions between all factors.     

电除尘器T/R设备的二次电压特性探讨

为探讨二次电压在电除尘器应用中的作用,针对二次电压包含的丰富信息,介绍了T/R设备二次电压额定值在当前世界上流行的3种含义后研究了在开路实验及可控硅关闭时的二次电压及其在型式实验中其波形特性对输出功率计算的影响。指出目前按电场冷态试验为主的T/R设备选型不利于提高其平均值,并提出2种解决方案:继续当前的设备选型方法,修改T/R设备各抽头的二次电压等级差规定;按电场热态工况进行设备选型,修改电除尘冷态试验标准。最后提出了反电晕的等效电路图,指出研究二次电压波形特征是反电晕检测控制的关键。     

湛江奥里油发电厂电除尘器前烟道注氨系统

燃用奥里油发电对改善能源结构具有积极意义,但奥里油高硫分、高钒的特性,导致燃烧产物中三氧化硫含量较高,容易产生酸结露,腐蚀烟气系统中的静电除尘器,影响除尘效果并损坏设备.广东湛江奥里油发电厂采取了静电除尘器前烟道注氨的技术措施.为此,针对氨的特性,阐释了氨的储存、蒸发及注入系统流程,并重点介绍了该系统设计特色及主要设备的选择.     

中压电缆终端高频电热老化试验装置的研制及分析

中压电缆终端被广泛应用于柔性交流输电和作为逆变器和电机的连接中,这些电缆终端可能会遭受到高频谐波电压的冲击,从而导致其绝缘迅速失效.本文研制了模拟电网高频谐波电压和工频大电流的电热老化试验装置.首先,通过信号发生器和功率放大器产生低压大电流信号,再通过高频变压器升压获得高频高压;同时通过工频试验变压器产生工频高压,将工...     

Analytical modelling of multilayer structure electronic devices for electrothermal layout optimisation

In this paper, an analytical model for the electrothermal solution to the non‐linear 3‐D heat flow equation for multilayer structure electronic devices is proposed. Compared with previous models presented in literature, it is general and can be easily applied to a large variety of integrated devices, provided that their structure can be represented as an arbitrary number of superimposed layers with a 2‐D embedded thermal source, so as to include the effect of the package. The proposed method is independent of the specific physical properties of the layers, hence GaAs MESFETs and HEMTs as well as silicon and silicon‐on‐insulator MOSFETs and heterostructure LASERs can be analysed. Moreover, it takes into account the dependence of the thermal conductivity of all the layers on the temperature; the heat equation is solved coupled with the device current–voltage relation in order to give physical consistence to the experimental evidence that a temperature increase causes a degradation of the electrical performances and that the electrical power is not uniformly distributed. Copyright © 2001 John Wiley & Sons, Ltd.     

静电除尘用高压供电电源特性浅析

为提高除尘效率,针对静电除尘器对供电电源的特殊要求,对其高压供电技术综合分析并讨论了多种高压供电方式、电源运行方式和控制方式的基本原理及对除尘效果的影响,指出脉冲供电方式和微机控制技术是当今静电除尘高压供电技术的主要发展方向和研究热点。     

电除尘器高压高频电源关键参数优化设计

以微细粉尘的荷电捕集机理为依据,对高压高频电源的电压波形、电压额定值、闪络判断处理、自适应工作方式等关键参数进行优化设计,不但能有效提高电场击穿场强和微细粉尘的荷电量,而且具有较强的工况自适应能力。与单相SCR电源相比,其节能效率可高达72.7%,粉尘排放减少30%~80%,是现阶段电除尘器的主流配套高压电源。     

高压静电除尘用电源调压特性的分析

为了得到高压静电除尘电源工作于串联谐振断续电流模式下的调压特性及选择一种适宜的控制方式,在分析电路工作原理的基础上,通过数学公式推导出了反映电路输出特性的解析表达式,分析了控制参数对电路调压特性的影响。通过仿真主要研究了调频、调占空比和调输入电压3种控制方式下电路特性的对比,结果表明,采用调节输入电压的控制方式具有较低的谐振电流峰值和有效值,是一种适合于高压静电除尘的控制方式,最后通过样机给出了实验结果。     

高压、超高压和特高压输变电工程防洪标准刍议

从标准条文间的协调性、工程设计气象重现期和结构使用年限等因素出发,对高压、超高压和特高压输变电工程的防洪标准进行了审视与梳理。建议高压、超高压变电工程的防洪重现期分别取50年和100年,特高压变电工程防洪重现期取100年及以上;各电压等级大跨越工程防洪标准应与相应等级的变电工程相同;高压、超高压以及特高压一般线路工程的防洪标准可适当降低,建议重现期分别取30年、50年和100年。     

1 000 MW 机组烟道布置优化

对国内1 000 MW机组锅炉电除尘器前后烟道在布置上 存在的问题进行了分析,并根据计算机模型进行了模拟计算 比较,提出了1 000 MW机组烟道的设计优化布置方案,目的 是既要减少烟道长度,降低烟道的金属耗量,又要保证除尘器 入口烟气流量分配均匀。     

Experimental modelling and intelligent control of a wood‐drying kiln

Proper control of the wood‐drying kiln is crucial in ensuring satisfactory quality of dried wood and in minimizing drying time. This paper presents the development, implementation, and evaluation of a control system for a lumber drying kiln process incorporating sensory feedback from in‐wood moisture content sensors and intelligent control such that the moisture content of lumber will reach and stabilize at the desired set point without operator interference. The drying process is difficult to model and control due to complex dynamic nonlinearities, coupling effects among key variables, and process disturbances caused by the variation of lumber sizes, species, and environmental factors. Through system identification scheme using experimental data and recursive least‐squares algorithm for parameter estimation, appropriate models are developed for simulation purpose and controller design. Two different control methodologies are employed and compared: a conventional proportional‐integral‐derivative (PID) controller and a direct fuzzy logic controller (FLC), and system performance is evaluated through simulations. The developed control system is then implemented in a downscaled industrial kiln located at the Innovation Centre of National Research Council (NRC) of Canada. This experimental set‐up is equipped with a variety of sensors, including thermocouples for temperature feedback, an air velocity transmitter for measuring airflow speed in the plenum, relative humidity sensors for measuring the relative humidity inside the kiln, and in‐wood moisture content sensors for measuring the moisture content of the wood pieces. For comparison, extensive experimental studies are carried out on‐line using the two controllers, and the results are evaluated to tune the controller parameters to achieve good performance in the wood‐drying kiln. The combination of conventional control with the intelligent control promises improved performance. The control system developed in this study may be applied in industrial wood‐drying kilns, with a clear potential for improved quality and increased speed of drying. Copyright © 2001 John Wiley & Sons, Ltd.     

一种实现高压电容器带电倾斜旋转实验平台的研制

为方便高压电容器的性能评价实验,研制了一种高压电容器倾斜旋转实验平台,可实现电容器在高电压下带电旋转、带电倾斜等功能。试验场地的地面水平、通过测试线引入的电磁骚扰、高压连接线牵引应力等问题,在高压电容器的精密测量中,可能引入不可忽略的影响。本文对这些影响因素提出了解决措施,并基于试验平台,定量分析评价了试验场地不平对高压电容器电容量变化的影响,降低了高压标准电容器在高精度测量中的不确定度,为高压标准电容器的性能评价试验提供了重要的支撑。     

光MOS继电器在正负高压电源极性切换中的应用

光MOS继电器是一种新型的固体继电器。讨论了应用光MOS继电器的开关特性,实现高压电源输出极性的快速切换,从而设计可靠的双极性小功率高压电源。介绍了光MOS继电器的结构、工作原理和作为高压开关应用的选型原则,讨论了光MOS继电器用于高压极性切换开关的两种实现方法,给出了在单逆变电路架构中应用光MOS继电器实现双极性高压输出的完善的应用电路。最后应用光MOS继电器、SG3525控制器等元件设计了一款应用于离子迁移谱仪器的双极性高压电源。     

智能电器监控单元静电放电敏感性的实验研究

为研究智能电器监控单元的静电放电敏感性,利用静电放电发生器对设备机壳放电进行了实验研究。根据静电放电干扰的耦合途径以及智能电器监控单元的实际工作情况,选取电源模块直流侧电压作为研究智能电器监控单元的静电放电敏感性的对象,通过频谱分析得出直流侧对地电压和静电放电电压间的关系。装置采取屏蔽、接地和滤波等抗干扰措施时其静电放电敏感性降低,分析直流侧电压发生的相应变化得出结论:静电放电时,智能电器监控单元直流侧对地电压与装置的静电放电敏感性有一定的相关性。     

A fast power loss calculation method for long real time thermal simulation of IGBT modules for a three‐phase inverter system

A fast power losses calculation method for long real time thermal simulation of IGBT module for a three‐phase inverter system is presented in this paper. The speed‐up is obtained by simplifying the representation of the three‐phase inverter at the system modelling stage. This allows the inverter system to be simulated predicting the effective voltages and currents whilst using large time‐step. An average power losses is calculated during each clock period, using a pre‐defined look‐up table, which stores the switching and on‐state losses generated by either direct measurement or automatically based upon compact models for the semiconductor devices. This simulation methodology brings together accurate models of the electrical systems performance, state of the art‐device compact models and a realistic simulation of the thermal performance in a usable period of CPU time and is suitable for a long real time thermal simulation of inverter power devices with arbitrary load. Thermal simulation results show that with the same IGBT characteristics applied, the proposed model can give the almost same thermal performance compared to the full physically based device modelling approach. Copyright © 2006 John Wiley & Sons, Ltd.     

A common setting for the design of iterative learning and repetitive controllers with experimental verification

Previous work has shown that the structure of repetitive control (RC) and that of iterative learning control (ILC) differ only in the location of an internal model of the disturbance. In this paper, it is shown how this common setting permits derivation of controllers in one domain based on an existing controller in the other. This is illustrated using the following case studies: 1) an RC scheme using a state feedback structure is derived based on an existing ILC scheme, which also uses state feedback (the underlying structure is first extended to comprise both current‐error feedback and previous‐error feedforward implementations); and 2) an ILC scheme using an output injection structure is developed based on an existing RC scheme, which uses state feedback, but differs from 1) by containing only a single internal model representation. All controllers are shown to have similar equivalent representations, with parameters derived by using linear quadratic regulator analysis. This correspondence enables comparison of the effect of the structure (ILC or RC, state feedback or output injection), number of internal models, and use of error (feedback or feedforward) on subsequent performance. This is undertaken using experimental results obtained using a gantry robot. Copyright © 2012 John Wiley & Sons, Ltd.     

高压、超高压和特高压输变电工程防洪标准刍议

从标准条文间的协调性、工程设计气象重现期和结构使用年限等因素出发,对高压、超高压和特高压输变电工程的防洪标准进行了审视与梳理。建议高压、超高压变电工程的防洪重现期分别取50年和100年,特高压变电工程防洪重现期取100年及以上;各电压等级大跨越工程防洪标准应与相应等级的变电工程相同;高压、超高压以及特高压一般线路工程的防洪标准可适当降低,建议重现期分别取30年、50年和100年。     

高压静电雾化雾滴粒径双峰分布概率密度模型

为预测毛细管—环电极配置的高压静电雾化系统下水静电雾化雾滴粒径的分布规律,采用颗粒动态分析仪测试了该系统的雾化雾滴粒径。当环电极电压在15~25 kV之间时,静电雾化模式为泰勒锥射流模式,雾滴粒径呈显著双峰分布规律,对此利用一种可双峰分布的概率密度函数建立了预测该模式下粒径分布规律的统计学模型,并与试验数据对比进行了误差分析,讨论了误差原因。结果表明:随着电压的增加,电场力耦合因素的影响将导致误差增大;在每个电压工况下最大误差均出现在双峰之间的谷值附近,但均<15%,总体上该模型能较好地与试验数据相符。