Abstract: Nonideal cable dispersive effects can affect system performance. This application note discusses the twomain loss effects related to cables (skin-effect and dielectric losses), and presents a simple method of modeling thecable for use in standard SPICE simulators.
上傳時(shí)間： 2014-11-18
上傳用戶(hù)：wxnumen
Abstract: A resistive feedback network is often used to set the output voltage of a power supply. A mechanical potentiometer (pot)conveniently solves the problem of adjusting a power supply. For easier automatic calibration, a mechanical pot can be replaced witha digital pot. This application note presents a calibration solution that uses a digital pot, because digipots are smaller, do not movewith age or vibration, and can be recalibrated remotely. This proposed solution reduces the susceptibility of the system to thetolerance of the digital pot's end-to-end resistance, making the solution optimal fordesigners. This application note also explainssome of the equations required to calculate the resistor chain values and to use a digital pot in this way. A spreadsheet withstandard reisistor values is available for easy calculations.
標(biāo)簽： 電源供應(yīng)器 數(shù)字電位器 應(yīng)用筆記 校準(zhǔn)
上傳時(shí)間： 2013-10-31
上傳用戶(hù)：caiguoqing
Automotive power systems are unforgiving electronicenvironments. Transients to 90V can occur when thenominal voltage range is 10V to 15V (ISO7637), along withbattery reversal in some cases. It’s fairly straightforwardto build automotive electronics around this system, butincreasingly end users want to operate portable electronics,such as GPS systems or music/video players,and to charge their Li-Ion batteries from the automotivebattery. To do so requires a compact, robust, effi cientand easy-to-design charging system
上傳時(shí)間： 2013-11-04
上傳用戶(hù)：wfl_yy
Many system designers need an easy way to producea negative 3.3V power supply. In systems that alreadyhave a transformer, one option is to swap out the existingtransformer with one that has an additional secondarywinding. The problem with this solution is that manysystems now use transformers that are standard, offthe-shelf components, and most designers want toavoid replacing a standard, qualifi ed transformer with acustom version. An easier alternative is to produce thelow negative voltage rail by stepping down an existingnegative rail. For example, if the system already employsan off-the-shelf transformer with two secondary windingsto produce ±12V, and a –3.3V rail is needed, a negativebuck converter can produce the –3.3V output from the–12V rail.
標(biāo)簽： 458 DN 降壓轉(zhuǎn)換器 低電壓
上傳時(shí)間： 2013-10-09
上傳用戶(hù)：Jerry_Chow
In a recent discussion with a system designer, the requirementfor his power supply was to regulate 1.5Vand deliver up to 40A of current to a load that consistedof four FPGAs. This is up to 60W of power that must bedelivered in a small area with the lowest height profi lepossible to allow a steady fl ow of air for cooling. Thepower supply had to be surface mountable and operateat high enough effi ciency to minimize heat dissipation.He also demanded the simplest possible solution so histime could be dedicated to the more complex tasks. Asidefrom precise electrical performance, this solution had toremovethe heat generated during DC to DC conversionquickly so that the circuit and the ICs in the vicinity do notoverheat. Such a solution requires an innovative designto meet these criteria:
標(biāo)簽： FPGA DCDC 集成 穩(wěn)壓器
上傳時(shí)間： 2013-11-24
上傳用戶(hù)：defghi010
為了改變目前電網(wǎng)現(xiàn)場(chǎng)作業(yè)管理的變電巡檢、變電檢修試驗(yàn)、輸電線(xiàn)路巡檢檢修等管理系統(tǒng)各自獨(dú)立運(yùn)行，信息不能共享，功能、效率受限，建設(shè)和維護(hù)成本高的現(xiàn)狀，提出了采用B/S+C/S構(gòu)架模式，將各現(xiàn)場(chǎng)作業(yè)管理模塊和生產(chǎn)MIS（管理系統(tǒng)）集成為一體的現(xiàn)場(chǎng)作業(yè)管理系統(tǒng)的設(shè)計(jì)方案，做到各子系統(tǒng)和生產(chǎn)MIS軟硬資源共享，做到同一數(shù)據(jù)唯一入口、一處錄入多處使用。各子系統(tǒng)設(shè)備人員等基礎(chǔ)信息來(lái)源于生產(chǎn)管理系統(tǒng)，各子系統(tǒng)又是生產(chǎn)管理系統(tǒng)的作業(yè)數(shù)據(jù)、缺陷信息的重要來(lái)源。經(jīng)過(guò)研究試用成功和推廣應(yīng)用，目前該系統(tǒng)已在江西電網(wǎng)220 kV及以上變電站全面應(yīng)用。 Abstract: In order to improve the status that the substation field inspection system， substation equipments maintenance and testing system， power-line inspection and maintenance system are running independent with each other. They can?蒺t share the resource information which accordingly constrains their functions and efficiency， and their construction and maintenance costs are high. This paper introduces a field standardized work management system based on B/S+C/S mode， integrating all field work management systems based on MIS and share the equipments and employee?蒺s data of MIS，the field work data of the sub systems are the source information of MIS， by which the same single data resouce with one-time input can be utilized in multiple places. After the research and testing， this system is triumphantly using in all 220kV and above substations in Jiangxi grid.
標(biāo)簽： 電網(wǎng) 信息化 管理系統(tǒng)
上傳時(shí)間： 2013-11-15
上傳用戶(hù)：han_zh
為解決直流逆變交流的問(wèn)題，有效地利用能源，讓電源輸出最大功率，設(shè)計(jì)了高性能的基于IR2101最大功率跟蹤逆變器，并以SPMC75F2413A單片機(jī)作為主控制器。高電壓、高速功率的MOSFET或IGBT驅(qū)動(dòng)器IR2101采用高度集成的電平轉(zhuǎn)換技術(shù)，同時(shí)上管采用外部自舉電容上電，能夠穩(wěn)定高效地驅(qū)動(dòng)MOS管。該逆變器可以實(shí)現(xiàn)DC/AC的轉(zhuǎn)換，最大功率點(diǎn)的跟蹤等功能。實(shí)際測(cè)試結(jié)果表明，該逆變器系統(tǒng)具有跟蹤能力強(qiáng)，穩(wěn)定性高，反應(yīng)靈敏等特點(diǎn)，該逆變器不僅可應(yīng)用于普通的電源逆變系統(tǒng)，而且可應(yīng)用于光伏并網(wǎng)發(fā)電的逆變系統(tǒng)，具有廣泛的市場(chǎng)前景。 Abstract: To solve the problem of DC-AC inverter， and to utilize solar energy more efficiently， the design of maximum power point tracking inverter based on IR2101 was achieved with a high-performance， which can make the system output power maximum. SPMC75F2413A was adopted as main controller. IR2101 is a high voltage， high speed power MOSFET and IGBT driver. It adopted highly integrated voltage level transforming technology， and an external bootstrap capacitor was used， which could drive MOS tube efficiently and stably. Many functions are achieved in the system， such as DC/AC conversion， maximun power point tracking， etc. The actual test result shows that the inverter system has characteristics of strong tracking ability， high stability and reacting quickly. The design can not only be used in ordinary power inverter system， but also be used in photovoltaic power inverter system. The design has certain marketing prospects
上傳時(shí)間： 2013-11-17
上傳用戶(hù)：lliuhhui
光伏發(fā)電是未來(lái)新能源發(fā)電重要方向之一，而光伏變流器是光伏發(fā)電系統(tǒng)的核心。介紹一種基于微網(wǎng)理念的光伏變流器設(shè)計(jì)。以該變流器為核心的光伏發(fā)電系統(tǒng)可以看做一個(gè)小型的微網(wǎng)系統(tǒng)。該系統(tǒng)能根據(jù)外部電網(wǎng)情況，工作于并網(wǎng)模式和離網(wǎng)模式。介紹了該系統(tǒng)的各個(gè)組成部件的設(shè)計(jì)以及變流器主電路部分器件的選型。最后，由實(shí)驗(yàn)樣機(jī)進(jìn)行測(cè)試。試驗(yàn)結(jié)果驗(yàn)證了電路拓?fù)浣Y(jié)構(gòu)及控制方案的可行性，也說(shuō)明了系統(tǒng)參數(shù)設(shè)計(jì)方法的正確性。 Abstract: Solar Photovoltaic generation is an important direction of new energy power generation in the future，while photovoltaic converter is the core of photovoltaic generation system. This paper deals with a study on photovoltaic inverter based on the concept of microgrid. This paper describes a system whose core component is the photovoltaic inverter，can work on grid-connected mode or run independently according to the external situation. The paper simply describes the main components of the system. At last，the prototype was produced and tested. Test result has proved feasibility of circuit topology structure and controlling scheme and shown correctness of system parameters.Key words: PV inverter； microgrid； off-grid； storage battery
標(biāo)簽： 光伏 變流器 系統(tǒng)設(shè)計(jì)
上傳時(shí)間： 2014-12-24
上傳用戶(hù)：Shaikh
When a system designer specifies a nonisolated dc/dc powermodule, considering the needed input voltage range isequally as important as considering the required performanceattributes and features. Generally, nonisolated moduleshave either a narrow or a wide input voltage range. Narrowinputmodules typically have a nominal input voltage of3.3, 5, or 12 V. For systems that operate from a tightlyregulated input bus—such as those that do not use batterybackup—a narrow-input module is often adequate sincethe input remains fairly stable.Offering greater flexibility, wide-input modules operatewithin a range of 7 to 36 V, which includes the popular12- or 24-V industrial bus. This enables a single module tobe used for generating multiple voltages. These modulesare ideal for industrial controls, HVAC systems, vehicles,medical instrumentation, and other applications that usea loosely regulated distribution bus. In addition, systemspowered by a rectifier/battery charger with lead-acidbattery backup almost always require wide-input modules.System designers who choose power supplies may wantto take a close look at the latest generation of wide-inputdc/dc modules.
標(biāo)簽： Wide-input modules offer dc
上傳時(shí)間： 2014-12-24
上傳用戶(hù)：dragonhaixm
[PIC項(xiàng)目實(shí)戰(zhàn)：基于PIC18].Advanced.PIC.Microcontroller.Projects.in.C
標(biāo)簽： PIC Microcontroller Advanced Projects
上傳時(shí)間： 2013-11-21
上傳用戶(hù)：二驅(qū)蚊器
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