用低压油伺服系统的常熟电厂#2机国产300MW汽轮机DEH、MEH控制系统改造成功

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光伏水泵系统

“光伏水泵系统”亦称“太阳能光电水泵系统” ,其基本原理是利用太阳电池将太阳能直接转换为电能 ,然后驱动各类电动机带动水泵从深井、江、河、湖、塘等水源提水。它具有无噪声、全自动（日出而作 ,日落而停）、高可靠、供水量与蒸发量适配性好（“天大旱 ,它大干”）等许多优点。联合国国际开发署（ＵＮＤＰ）、世界银行（ＷＢ）、亚太经社会（ＥＳＣＡＰ）等国际组织都先后充分肯定了它的先进性与合理性 ,目前在这些国际组织的支持下 ,全世界已有数万台不同规格的光伏水泵在不同地区和国家运行 ,特别是在亚、非、拉及中东等发展中国家 ,…     

太阳电池硅片ELCC技术用复合梯度涂层的研究

低成本太阳电池硅片电磁悬浮熔炼离心铸造（ＥＬＣＣ）技术可大幅度降低太阳电池的成本。硅片脱模技术是ＥＬＣＣ技术的关键之一。综合运行液相反应生成法，反应烧结法和溶胶－凝胶法，成功地在石墨基体表面制备了ＳｉＣ－Ｓｉ３Ｎ４－（Ｓｉ３Ｎ４＋ＳｉＯ２）复合梯度涂层，并用Ｘ射线衍射法（ＸＲＤ）、扫描电镜（ＳＥＭ）和界面性能测定仪（ＩＣＭ）考察了该涂层的组织结构和性能。     

先进的CAE技术以及在我厂产品中的应用

先进的ＣＡＥ技术以及在我厂产品中的应用刘岩，胡世红１前言去年６月，我厂从美国ＥＤＳ公司购买Ｔ８套ＣＡＤ／ＣＡＭ／ＣＡＥ软件和１套美国ＭＳＣ公司的外置求解器——一ＮＡＳＴＲＡＮ，以及它自备的前后处理软件ＸＬ。一年多来，在厂各级领导的关心下，ＣＡＤ技术在...     

SURFCAM与Pro/ENGINEER在三维造型和加工方面的性能比较

本文介绍了ＳＵＲＦＣＡＭ、Ｐｒｏ／ＥＮＧＩＮＥＥＲ各自的主要功能和特点,还以Ｃ１２１－ ＤＵ－Ｄ３７连杆体锻模为例, 从三维几何造型、 加工参数的选择以及生成刀具加工轨迹等几个方面,对ＳＵＲＦＣＡＭ与Ｐｒｏ／ＥＮＧＩＮＥＥＲ进行了详细而又具体的分析和比较。     

光伏水泵系统中CVT及MPPT的控制比较

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光伏系统的运行和维护（Ⅰ）光伏阵列美国ＭａｒｋＭｃＣｒａｙ博士在ＳｏｌａｒＴｏｄａｙ杂志上连续发表了关于住宅光伏系统的运行和维护的文章。为引起我国光电用户的注意，学习和了解一些必要的维护知识，本刊从这期起将逐篇加以介绍。建议每年至少进行两次常规检验。...     

Performance analysis of PV pumping systems using switched reluctance motor drives

A PV pumping system using switched reluctance motor (SRM) is thoroughly investigated in this work. This motor is supplied by a d.c. voltage through a simple switching circuit. This drive circuit is much simpler than the normal d.c./a.c. inverter required to supply the induction motor. The efficiency of this motor is considerably higher than that of the equivalent d.c. or induction motors. In addition, because of the simple construction, SRM is cheaper than these conventional drives. Because of the above advantages of the SRM, the proposed system has higher efficiency and lower cost as compared with other systems.A design example is studied in detail to explore the advantages of PV pumping systems based on this new drive. The study of the performance of the proposed system showed that the operating efficiency of the motor is about 85% during most of its working time. The matching efficiency between the PV array and the proposed system approaches 95%. The major part of the losses takes place in the pump and the riser pipes, this loss represents one-third of the total available energy.     

Sizing and modelling of photovoltaic water pumping system

With the decline in price of the photovoltaics (PVs) their use as a power source for water pumping is the most attractive solution instead of using diesel generators or electric motors driven by a grid system. In this paper, a method to design a PV pumping system is presented and discussed, which is then used to calculate the required size of the PV for an existing farm. Furthermore, the amount of carbon dioxide emissions saved by the use of PV water pumping system instead of using diesel-fuelled generators or electrical motor connected to the grid network is calculated. In addition, an experimental set-up is developed for the PV water pumping system using both DC and AC motors with batteries. The experimental tests are used to validate the developed MATLAB model. This research work demonstrates that using the PV water pumping system is not only improving the living conditions in rural areas but it is also protecting the environment and can be a cost-effective application in remote locations.     

微机智能控制直流系统在沙集泵站中的应用

为了解决沙集泵站原有直流系统存在的可靠性差、配置不合理等问题,对原有的直流系统进行了改造,微机智能控制直流系统综合了高频开关技术和计算机技术,达到了美观大方、操作简便、运行稳定、自动化水平高、维护方便的要求,在沙集站直流系统安全供电方面发挥了重要作用。     

A fuzzy global efficiency optimization of a photovoltaic water pumping system

This paper presents an on-line fuzzy optimization of the global efficiency of a photovoltaic water pumping system driven by a separately excited DC motor (DCM), a permanent magnet synchronous motor (PMSM), or an induction motor (IM), coupled to a centrifugal pump.The fuzzy optimization procedure stated above, which aims to the maximization of the global efficiency, will lead consequently to maximize the drive speed and the water discharge rate of the coupled centrifugal pump. The proposed solution is based on a judicious fuzzy adjustment of a chopper ratio which adapts on-line the load impedance to the photovoltaic generator (PVG). Simulation results show the effectiveness of the drive system for both transient and steady state operations. Hence it is suitable to use this fuzzy logic procedure as a standard optimization algorithm for such photovoltaic water pumping drives.     

Analysis and development of a low-cost permanent magnet brushless DC motor drive for PV-array fed water pumping system

This paper deals with the analysis and development of a permanent magnet brushless DC (PMBLDC) motor drive coupled to a pump load powered by solar photovoltaic (PV) array for water pumping system. A simple low-cost prototype controller has been designed and developed without current and position sensors which reduces drastically the overall cost of the drive system. This controller is used to test the dynamic behavior of the PMBLDC motor drive system. The mathematical model of the system is developed with a view to carry out a comparison between experimental and simulated response of the drive system. A simple filter circuit incorporated in between PV-array and an inverter to reduce ripples and to improve the performance of the PV-array. The necessary computer algorithm is developed to analyze the performance under different conditions of varying solar insolation for a pump load.     

The operation of permanent magnet DC motors powered by a commonsource of solar cells

In a photovoltaic water-pumping system, the solar cell array is usually designed to power a single motor-load pump. Several water-pumping systems of the same or different types that are in close proximity to each other can be powered by separate solar cell arrays (sources) for each one, or, alternatively, by a common solar cell source for all the water pumping systems. The authors introduce a procedure for comparing the performances of these two setups. One system includes a permanent magnet DC motor and a volumetric pump, and the other a permanent magnet DC motor and a centrifugal pump. The comparison was also done for the same systems when a maximum-power point tracker (MPPT) was included for both the separate and the common solar cell source. It is shown, for example, that in systems not including MPPTs the total performance of the two motor-pumps in the common source system is improved as compared to the performance of the two motor-pumps when they are powered separately by individual sources     

Integrated solar pump design incorporating a brushless DC motor for use in a solar heating system

Most solar thermal hot water heating systems utilize a pump for circulation of the working fluid. An elegant approach to powering the pump is via solar energy. A “solar pump” employs a photovoltaic module, electric motor, and pump to collect and convert solar energy to circulate the working fluid. This article presents an experimental investigation of a new integrated solar pump design that employs the stator of a brushless DC motor and a magnetically coupled pump that has no dynamic seal. This design significantly reduces total volume and mass, and eliminates redundant components.The integrated design meets a hydraulic load of 1.7 bar and 1.4 litres per minute, equal to 4.0 watts, at a rotational speed of 500 revolutions per minute. The brushless DC motor and positive displacement pump achieve efficiencies of 62% and 52%, respectively, resulting in an electric to hydraulic efficiency of 32%. Thus, a readily available photovoltaic module rated 15 watts output is suitable to power the system.A variety of design variations were tested to determine the impact of the armature winding, pump size, pulse width modulation frequency, seal can material, etcetera. The physical and magnetic design was found to dominate efficiency. The efficiency characteristics of a photovoltaic module are such that over-sizing is wasteful.The integrated design presents a robust, efficient package for use as a solar pump. Although focus has been placed on application to a solar thermal collector system, variations of the design are suitable for a wide variety of applications such as remote location water pumping.     

A novel multilayer switched reluctance motor

The switched reluctance motor is a simple and robust machine, which has found application over wide power and speed ranges in different shapes and geometries. This paper introduces a new configuration for a high starting torque switched reluctance motor (SRM). This configuration allows more space for coil windings in small size motors with a high number of stator and rotor poles. It also presents a centrifugal switch mounted on the motor shaft for a sudden advancement of current-pulses relative to rotor position after reaching a preset motor speed in order to develop higher torque at starting. To evaluate the motor performance, two types of analysis, namely numerical techniques and an experimental study have been utilized. In the numerical analysis, due to the highly nonlinear nature of the motor, a finite element analysis is employed, and for the experimental study, a prototype motor has been built and tested. Finally, the prototype motor is compared with a conventional SRM of the same size. The calculated results compare favorably with the test results. In comparison with the conventional SRM, the proposed motor in this paper seems to be very promising     

Solar powered induction motor-driven water pump operating on a desert well, simulation and field tests

A photovoltaic-powered water pumping system, employing an induction motor pump, capable of supplying a daily average of 50 m³ at 37-m head has been developed. The system was installed on a desert well in Jordan, where: the average solar radiation amount to 5.5 kW h/m³/day, to provide the Bedouins living in the well area with drinking water.A mathematical model to enable testing the system performance by computer simulation was developed. This model allows the representation of motor torque in function of speed (and slip) at different supply frequencies, as well as the flow rate and efficiency of the system in function of supply frequency and pumping head.Prior to its installation on the desert well, the system performance, in accordance with frequency and head, was thoroughly tested in the laboratory. As illustrated in this paper, simulation and laboratory testing results are well matched. At constant pumping head, the flow rate is proportional to the supply frequency of the motor. At constant flow rate, the pumping head is proportional to the supply frequency squared only in the range below the peak efficiency of the pump. For higher flow rate values, a special algorithm based on the experimental results could be developed.Higher system efficiency is achievable at higher frequency. It is advisable to operate the motor pump at the nominal frequency, flow rate and head corresponding to maximum efficiency.Long-term field testing of the system shows that it is reliable and has an overall efficiency exceeding 3%, which is comparable to the highest efficiencies reported elsewhere for solar powered pumps.