Centrifugal pump operation monitoring with motor phase current measurement

Centrifugal pumps often operate inefficiently because of their incorrect dimensioning and inefficient control. The economic potential of improving the pumping efficiency has generated a wide market for energy auditing products and services, which determine the prevailing energy efficiency of pump operation. Energy audits are commonly based on additional measurements that might be carried out for a short period of time, covering only a fraction of the pump operation cycle. Often the most feasible solution would be to use the existing measurements in the pumping system to determine its typical operation. Then, the correctness of pump dimensioning and the efficiency of the applied flow control method could be determined simultaneously for a large group of pumps, as there would be no requirements for additional measurement sensors on each device.In this paper, a current measurement-based approach to monitor centrifugal pump operation and its energy efficiency is studied. This approach allows a simple realization of energy audits for fixed-speed pumping systems, where only current consumption of the electric motor is measured. Approach is based on adjustable models for motor and pump operation, which in this case are configured for a laboratory pumping system. Factors affecting the estimation accuracy of the motor operation are also analyzed in the paper. According to the conducted tests with the laboratory setup, the motor shaft power can be estimated with the accuracy of 3.2%, and the pump flow rate with the accuracy of 16%. This accuracy class can be considered sufficient for energy auditing and monitoring purposes, since it allows detection of inefficiently operating pumps. After this, more accurate measurements with separate measurement instrumentation and more detailed pumping system energy efficiency analysis can be carried out.     

一种新型的小汽轮机给水泵变速恒频发电系统

为节能减排,火力发电厂采用主汽轮机再热蒸汽驱动小汽轮机带动锅炉给水泵供水,通过调节小汽轮机进汽阀开度的方式来控制转速。但该方案在阀门处产生节流损失,轻载时对系统效率影响更大。为此,提出一种小汽轮机、给水泵和电机三者同轴连接结构,用全功率变流器驱动电机,实现给水泵变频调速,并将剩余能量馈回电网,实现节能。运行时阀门全开,调节电机电磁转矩来吸收轴系功率,平稳快速控制给水泵速度,避免阀门损耗。从汽轮机-给水泵的转速转矩及机械耦合特性出发,建立了该发电系统的数学模型,针对工况切换下的调速要求,研究了运行稳定性和抑制功率波动尖峰的控制策略及控制参数设计。最后通过仿真分析以及小功率系统的物理动模实验,验证了系统运行的可行性和有效性。     

混合式直线步进电动机控制技术

介绍了一种航空放油阀用混合式直线步进电动机驱动控制系统。分析了电机的工作原理，并对电机的末端冲击、平稳运行等关键技术进行了研究，给出了单片机及其细分控制电路和末端降速控制方法。试验结果表明：该电机可作为直线阀门的直接驱动部件。     

永磁涡流柔性传动的结构、特点与性能分析

永磁涡流柔性传动(MEFD)是近二十年发展起来的新技术,为工业速度控制增加了新的选择。分析了三种结构不同特点,三筒型结构设计合理利用了空间,结构紧凑,尤其适于大功率机械的调速传动。理论与试验表明:MEFD用于泵、风机等离心流体机械比用阀门、挡板节流调节流量压力节能10%~30%。滑动率小于20%,MEFD效率通常比变频调速低2%~4%。滑动率大于50%,变频调速效率往往是MEFD的2倍。MEFD尤其适于软启动、减振与过载保护要求、高压电机、大功率以及无电源发动机驱动的场合。     

VF drives as final control elements in the petroleum industry

In this paper, the authors present application guidelines for the correct selection of a variable speed motor drive for use with a centrifugal pump to provide flow, pressure or temperature control     

软起动器泵控功能消除泵系统喘振的机理

泵系统在电动机起动和停止时,容易产生液流冲击和喘振。本文根据电动机及泵系统的特性,分析产生喘振的原因及泵控制消除喘振的机理,指出消除喘振的最佳方法是使用具有泵控功能的软起动器。     

中国高端真空泵驱动电机及控制技术的现状和发展

真空泵作为真空获得的重要设备,在电子芯片、大规模集成电路、精细化工、生物制药、光伏产业等领域受到了广泛关注及应用,其性能指标很大程度取决于驱动电机及其控制技术。介绍了真空泵驱动电机的基本种类与工作原理,总结了共性规律和个性特点,对其拓扑结构、冷却方式和智能控制等关键技术进行综述,分析了真空泵驱动电机在特殊工况条件下的控制策略问题。最后,对真空泵驱动电机及其控制系统的主要研究方向进行了展望。     

10 kV变频器在输油站离心泵电机控制的应用

为了验证异步电机变频调速在输油站应用的实际应用效果,进行了变频调速泵(离心泵)的工作特性分析、运动流体的能量分析和电机功率因数的分析。然后,对某输油站串联安装且同时运行的变频离心泵和非变频(工频)离心泵近一年的运行数据进行分析验证。理论分析和数据统计分析的结果一致。结果表明异步电动机变频调速(降频)运行后,节能效果显著,且输油管道压力调节范围更大,提高了电机的功率因数。     

大型同步电动机组的软起动软停机

针对高扬程大型离心水泵采用"闭阀起泵,关阀停泵"的工作方式,开停泵时对机组及配套设备产生较大冲击现象,提出对所配套的同步电机采用软起动停机技术,以减轻振动,延长设备使用寿命.     

基于IGBT斩波控制的内反馈串级调速系统的研究

晶闸管串级调速系统是一种廉价、简易的调速系统,但是传统串调系统存在着诸如功率因数低、谐波污染严重等弊端。在分析其原理及结构的基础上,讨论了影响其功率因数的主要因素。斩波内馈串级调速系统采用绝缘栅双极性晶体管(IGBT)作为调速系统的直流斩波器,提高了系统的功率因数且降低了谐波成分,减少了对电网的谐波污染,使得该调速系统在大功率风机、泵类负载的节能调速方面具有广阔的应用前景。     

长供水管道水泵出口阀门的选择

某泵站供水管道较长,扬程较高,水泵突然断电,水泵出口阀门关闭时,沿整个管线都出现了危及管道安全的水柱分离现象,因此采取了附加惯性飞轮的负水锤防护措施以及在水泵出口安装二段关闭阀门的正水锤防护措施。计算结果表明：正负水锤防护措施的有效结合,避免了严重的水锤压力,保证了管道运行的安全;对长供水管道,水泵出口安装液控蝶阀比微阻缓闭止回阀的水锤防护效果好。     

Production Operation of Submersible Pumps with Closed-Loop Adjustable Speed Control

Submersible pump performance in a given installation is determined by the intersections of the pumping load line with the pump capability curves. With fixed pump speed, the operating point on the head-capacity curve moves as the well productivity changes, and operation may be then outside the desired range. Efficiency and reliability are thereby reduced. With adjustable speed pumping, the operating point may be held within the desired range at high efficiency, while production is changed to match the well capability. Cycling or throttling may be avoided. Production is optimized if the well fluid level is held as low as possible, while avoiding pump-off, cavitation or gas-lock conditions. This may be achieved by using closed-loop control of pump speed with the feedback of either downhole pressure or motor current data or both. Practical experience has demonstrated the reliability of these techniques and the resulting ability to confidently operate with a lower fluid level, which is maintained constant through changing productivity.     

同步机节能调节技术的研究

根据电机学及拖动原理,分析了泵站运行及原理测试参数,研究了泵站和同步电动机的效率及励磁损耗,设计了大型同步电动机自动调节励磁的节能控制器,论述了该装置的调节原理与系统设计。     

一种航空用直线直流步进电机控制系统设计

研究了一种飞机油阀用直线直流步进电机及其控制系统。混合式直线直流步进电机直流驱动替代目前的有刷直流电动机的间接驱动,简化了繁琐的蜗轮蜗杆机构;细分技术使步进电机运行平稳,消除了间接驱动的弊端,提高了飞机油阀驱动控制系统的技术水平。     

城市污水泵站大功率水泵电机的均衡运行和自动轮值控制

在无人值守的城市污水泵站自动监控系统中,大功率水泵电机是主要的控制对象。文章通过对某一污水泵站控制要求的分析,在系统控制的可靠性和控制实现的简洁性、经济性之间寻优,给出了实现数台大功率水泵电机的均衡运行和自动轮植控制的一种方法。     

真空干泵用两种驱动电机热特性对比分析

真空干泵驱动电机散热困难,需要严格控制其的温升,进而保证系统的长时间运行。以30 kW驱动电机为研究对象,设计了一台异步电机和一台18/12极双凸极永磁电机。两种电机的外形尺寸和功率等级等条件相同。同时,两种电机的冷却方式均采用机壳通有螺旋水道的水冷,分别对两种电机进行了温度场分析。分析结果表明,在额定运行时双凸极永磁电机具有更低的整体温升,更加适用于真空干泵机组。     

A study on high-output piezoelectric micropumps for application in DMFC

In order to supply liquid fuel in DMFC (Direct Methanol Fuel Cell) system, a small but high-output micropump is needed. This study presents a design concept, fabrication and experimental results of the newly devised piezoelectric micropump by using resonance and fluid inertia. The micropump consists of a resonantly-driven pumping unit, an inlet check valve, and a pipeline element with a small diameter employed in an outlet. The resonance mechanism is used to oscillate the pumping chamber. It simply magnifies a small displacement of the used multilayer-piezoelectric actuator. The fluid inertia effect uses a fast flow through a narrow pipeline element employed instead of the outlet check valve. First, an analysis on each element such as a diaphragm and a check valve is performed. Based on the obtained analysis results, a prototype micropump is designed, and fabricated. Then, pumping characteristics such as frequency-dependent displacement, and flow rate without load pressure are experimentally investigated. Finally, a refabrication of the micropump is carried out to improve load characteristics, and the obtained experimental results are presented and discussed.     

真空干泵驱动电机冷却效果分析

针对真空泵用驱动电机在极端真空环境工作时发热严重的问题,对真空泵用电机的冷却系统进行设计和分析。以1台2.9 kW屏蔽式异步电机作为研究对象,通过有限元软件建立机壳带有螺旋水路的电机三维模型,对其进行损耗计算。根据螺旋水道的流速和压强分布验证了水道尺寸设计的合理性,并对电机各部分温度分布情况进行仿真分析。根据电机在二倍额定负载和冷却水故障条件下的温度变化情况来分析电机能安全运行的时间。最后对样机进行了温升试验,将得到的测试结果和仿真结果进行对比分析,验证了机壳带有螺旋水道的冷却系统对真空干泵驱动电机具有一定的冷却效果,为极端真空环境下真空泵用驱动电机的进一步研究提供科学依据。     

游梁式抽油机变频驱动系统中发电状态的解决

介绍了游梁式抽油机的工作特性,详细分析了抽油机运行时三相异步电机产生“倒发电”现象的原因。设计了基于变频驱动系统的专用控制算法来解决“倒发电”问题。现场实验证明,该解决方案能根据电机运行状况实时、连续地调节其运行频率,从而达到节能增效的目的。     

Prospects for advancement in the energy efficiency of oil-producing sucker rod pumps

This paper considers variants for improving the energy efficiency of oil-producing sucker rod pumps with new alternative electric drives based on valve electric motors instead of existing ones based on serial asynchronous motors. As an option, the drive of a sucker rod pump with a linear cylindrical motor valve motor is proposed.