Verilog-IEEE Std 1364 -2005 IEEE Standard
Verilog的IEEE标准，比较新的一个吧应该是IEEE Std 1364 TM-2005(Revision of IEEE Std 1364-2001)lEE Standard for VerilogHardware Description LanguageSponsorDesign Automation Standards Committeeof theIEEE Computer SocietyAbstract: The Verilog hardware description language(HDL) is defined in this standard. VerilogHDL is a formal notation intended for use in all phases of the creation of electronic systems. Because it is both machine-readable and human-readable, it supports the development, verificationsynthesis, and testing of hardware designs; the communication of hardware design data; and themaintenance, modification, and procurement of hardware. The primary audiences for this standardare the implementors of tools supporting the language and advanced users of the languageKeywords: computer, computer languages, digital systems, electronic systems, hardware, hardware description languages, hardware design, HDL, PLI, programming language interface, Verilog,Verilog HDL, verilog PllThe Institute of Electrical and Electronics Engineers, Inc3 Park Avenue. New york. NY 10016-5997 USACopyright@ 2006 by the Institute of Electrical and Electronics Engineers, IncAll rights reserved Published 7 April 2006. Printed in the United states of AmericaIEEE is a registered trademark in the U.S. Patent Trademark Office, owned by the Institute of Electrical and ElectronicsEngineers, IncorporatedVerilog is a registered trademark of Cadence Design Systems, IncPrint:|sBN0-738148504SH95395PDFSBN0-7381-48512SS95395No part of this publication may be reproduced in any form, in an electronic retrieval system or otherwise, without the priorwritten permission of the publisher.IEEE Standards documents are developed within the IEee Societies and the Standards CoordinatingCommittees of the iEEE Standards Association (IEEE-SA)Standards board The ieee develops its standardsthrough a consensus development process, approved by the american National Standards Institute, which bringstogether volunteers representing varied viewpoints and interests to achieve the final product. Volunteers are notnecessarily members of the Institute and serve without compensation. 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Suggestions for changes in documents should be in the form of a proposed change of texttogether with appropriate supporting comments Comments on standards and requests for interpretations shouldaddressed toIEEE-SA Standards Board445 Hoes lanePiscataway, NJ 08854USANoTE-Attention is called to the possibility that implementation of this standard may require use of subjectmatter covered by patent rights. By publication of this standard, no position is taken with respect to theexistence or validity of any patent rights in connection therewith. The IEf shall not be responsible foridentifying patents for which a license may be required by an ieee standard or for conducting inquiries into thelegal validity or scope of those patents that are brought to its attentionAuthorization to photocopy portions of any individual standard for internal or personal use is granted by the Institute of Electrical and Electronics Engineers, Inc, provided that the appropriate fee is paid to Copyright ClearanceCenter. To arrange for payment of licensing fee, please contact Copyright Clearance Center, Customer Service222 Rosewood Drive, Danvers, MA01923 USA; +19787508400. Permission to photocopy portions of any indi-idual standard for educational classroom use can also be obtained through the Copyright Clearance CenterIntroductionThis introduction is not a part of IEEE Std 1364-2005, IEEE Standard for Verilog Hardware Description LanguageThe Verilog hardware description language(HDL) became an IEEE standard in 1995 as IEEE Std 13641995. It was designed to be simple, intuitive, and effective at multiple levels of abstraction in a standardtextual format for a variety of design tools, including verification simulation, timing analysis, test analysisand synthesis. It is because of these rich features that verilog has been accepted to be the language of choiceby an overwhelming number of integrated circuit(IC)designersVerilog contains a rich set of built-in primitives, including logic gates, user-definable primitives, switches,and wired logic. It also has device pin-to-pin delays and timing checks. The mixing of abstract levels isessentially provided by the semantics of two data types: nets and variables. Continuous assignments, inwhich expressions of both variables and nets can continuously drive values onto nets, provide the basicstructural construct. Procedural assignments, in which the results of calculations involving variable and netvalues can be stored into variables, provide the basic behavioral construct. a design consists of a set of modules, each of which has an input/output(1/O)interface, and a description of its function, which can be structural, behavioral, or a mix. These modules are formed into a hierarchy and are interconnected with netsThe Verilog language is extensible via the programming language interface(PLI)and the verilog procedural interface(VPi) routines. The Pli/vPi is a collection of routines that allows foreign functions to accessinformation contained in a Verilog hdl description of the design and facilitates dynamic interaction withsimulation. Applications of PLI/VPI include connecting to a Verilog HDL simulator with other simulationand computer-assisted design(CAD)systems, customized debugging TaskS, delay calculators, andannotatorsThe language that influenced Verilog HDL the most was HILO-2, which was developed at Brunel University in England under a contract to produce a test generation system for the British Ministry of DefensehiLO-2 successfully combined the gate and register transfer levels of abstraction and supported verificationsimulation, timing analysis, fault simulation, and test generationIn 1990, Cadence Design Systems placed the Verilog HDL into the public domain and the independentOpen Verilog International(oVi)was formed to manage and promote Verilog HDL. In 1992, the Board ofDirectors of ovi began an effort to establish Verilog hdl as an ieeE standard. In 1993, the first IEeEworking group was formed; and after 18 months of focused efforts, Verilog became an IEEE standard asIEEE Std 1364-1995After the standardization process was complete, the IEEe P1364 Working Group started looking for feedback from IEEE 1364 users worldwide so the standard could be enhanced and modified accordingly. Thisled to a five-year effort to get a much better Verilog standard in IEEE Std 1364-2001With the completion of IEEE Std 1364-2001, work continued in the larger Verilog community to identifyoutstanding issues with the language as well as ideas for possible enhancements. As Accellera began work-ing on standardizing System Verilog in 2001, additional issues were identified that could possibly have led toincompatibilities between Verilog 1364 and System Verilog. The IEEE P1364 Working group was established as a subcomittee of the System Verilog P1800 Working Group to help ensure consistent resolution ofsuch issues. The result of this collaborative work is this standard ieee Std 1364-2005Copyright C 2006 IEEE. All rights reservedNotice to usersErrataErrata,ifanyforthisandallotherstandardscanbeaccessedatthefollowingurL:http:/stan-dards.ieee.org/reading/ieee/updates/errata/index.html. Users are encouraged to check this URL for errataperiodicaInterpretationsCurrentinterpretationscanbeaccessedatthefollowingUrl:http:/standards.ieeeorg/reading/ieee/interp/Index. htmlPatentsAttention is called to the possibility that implementation of this standard may require use of subject mattercovered by patent rights. By publication of this standard, no position is taken with respect to the existence orvalidity of any patent rights in connection therewith. The IEee shall not be responsible for identifyingpatents or patent applications for which a license may be required to implement an IEEE standard or forconducting inquiries into the legal validity or scope of those patents that are brought to its attentionParticipantsAt the time this standard was completed, the ieee P1364 Working group had the following membershipJohny Srouji, IBM, IEEE SyStem verilog Working Group chairTom Fitzpatrick, Mentor Graphics Corporation, ChairNeil Korpusik, Sun Microsystems, Inc, Co-chairStuart sutherland sutherland hdl inc. editorShalom Bresticker, Intel Corporation, Editor through February 2005The Errata Task Force had the following membershipKaren pynopsys,rKurt baty. WFSDB ConsultinDennis marsa. XilinxStefen Boyd, Boyd TechnologyFrancoise Martinolle, Cadence Design Systems, IncShalom Bresticker, Intel CorporationMike McNamara, Verisity, LtdDennis Brophy, Mentor Graphics CorporationDon Mills, LCDM EngineeringCliff Cummings, Sunburst Design, IncAnders nordstrom, Cadence Design Systems, IncCharles dawson, Cadence Design Systems, IncKaren Pieper, Synopsys, IncTom Fitzpatrick, Mentor Graphics CorpoBrad Pierce, Synopsys, IncRonald goodstein, first shot Logic simulation andSteven Sharp Cadence Design Systems, IncAlec Stanculescu. Fintronic USA IncDesignStuart Sutherland. Sutherland HDL IncMark Hartog, Synopsys incGordon Vreugdenhil, Mentor Graphics CorporationJames Markevitch, Evergreen Technology GroupJason Woolf, Cadence design Systems, IncCopyright C 2006 IEEE. All rights reservedThe behavioral Task Force had the following membership:Steven Sharp, Cadence Design Systems, InC, ChairKurt Baty, WFSDB ConsultingJay lawrence. Cadence design Systems. IncStefen Boyd, Boyd TechnologyFrancoise Martinolle, Cadence Design Systems, IncShalom Bresticker, Intel CorporationKathryn McKinley, Cadence Design Systems, IncDennis brophy, Mentor graphics corporationMichael mcnamara. Verisity LtdCliff Cummings, Sunburst Design, IncDon Mills, LCDM EngineeringSteven Dovich, Cadence Design Systems, IncMehdi Mohtashemi, Synopsys, IncTom Fitzpatrick, Mentor Graphics CorporationKaren Pieper, Synopsys, IncRonald Goodstein, First Shot Logic Simulation andBrad Pierce, Synopsys, IncDesignDave Rich, Mentor Graphics CorporationKeith Gover, Mentor Graphics CorporationSteven Sharp, Cadence Design Systems, IncMark Hartoog, Synopsys, IncAlec Stanculescu. Fintronic USAEnnis Hawk, Jeda TechnologiesStuart Sutherland. Sutherland hdl. IncAtsushi kasuya, Jcda TechnologicsGordon Vrcugdcnhil, Mentor Graphics CorporationThe PLI Task Force had the following membershipCharles Dawson, Cadence Design Systems, Inc, ChairGhassan Khoory, Synopsys, Inc Co-chairTapati Basu, Synopsys, IncMichael rohleder. Freescale Semiconductor. IncSteven Dovich, Cadence Design Systems, IncRob Slater, Freescale Semiconductor IncRalph duncan, Mentor Graphics CorporationJohn Stickley, Mentor Graphics CorporationJim garnett, Mentor Graphics CorporationStuart Sutherland. Sutherland HDL. incJoao geada CLK Design AutomationBassam Tabbara. Novas software. IncAndrzej litwiniuk, Synopsys, IncJim Vellenga, Cadence Design Systems, IncFrancoise Martinolle, Cadence Design Systems, IncDoug Warmke, Mentor Graphics CorporationSachchidananda Patel, Synopsys, IncIn addition, the working group wishes to recognize the substantial efforts of past contributorsMichael McNamara, Cadence Design Systems, Inc1364 Working Group past chair(through September 2004)Alec Stanculescu, Fintronic USA, 1304 Working Group past vice-chair(through June 2004)Stefen Boyd, Boyd Technology, ETF past co-chair(through November 2004)The following members of the entity balloting commitlee voted on this standard. Balloters may have votedfor approval, disapproval, or abstentionAccelleraIntel CorporationBluespec, Inc.Mentor Graphics CorporationCadence Dcsign Systcms, IncSun microsystems, IncIntronic u.s.aSunburst design, IncIBMSutherland hdl lncInfineon TechnologiesSynopsys, IncCopyright C 2006 IEEE. All rights reservedWhen the IEEE-SA Standards Board approved this standard on 8 November 2005, it had the followingmembershipSteve M. mills. chairRichard h. hulett vice chairDon wright Past chairJudith gorman. secretaryMark d. bowmanWilliam B HopfT W. olsenDennis B. BrophyLowell G. JohnsonGlenn parsonsJoseph brudeHerman KochRonald c. petersenRichard coxJoseph L. Koepfinger*Gary s. RobinsonBob davisDavid J lawFrank stoneJulian forster kDaleep c mohlaMalcolm v thadenJoanna n. gueninPaul nikolichRichard l. townsendS. HalpJoe d. watseRaymond hapemanHoward L, wolfmanAlso included are the following nonvoting Ieee-Sa Standards board liaisonsSatish K. aval, NRC RepresentativeRichard Deblasio, DOE RepresentativeAlan H. Cookson, NIST RepresentativeMichelle d, trIEEE Standards Project EditoCopyright C 2006 IEEE. All rights reservedContentsOverview1. 2 Conventions used in this standard1.3SIption1 4 Use of color in this standard1.5 Contents of this standard1.6 Deprecated clauses……….….….….…1.7 Header file listings....18 Examples…………………1.9PNormative references63. Lexical conventions83.1 Lexical tokens3.2 White space3. 3 Comments中··…·········:···············中·····“:·:·:·4·····“··········3. 4 Operators3. 5 Numberssteger constants3.5.2 Real constants123.5.3 Conversion123.6 Strings123.6. 1 String variable declaration133.6.2 String manipulation133.6.3 Special cha3.7 Identifiers. keds, and syste143.7.1 Escaped identifiers143.7.2 Keywords153.7.3 System tasks and functions3.7.4 Compiler directives153.8 Attrib163.8.1 Examples3.8.2 SyIata typ··4.1 Val214.2 Nets and variables4.2.1 Net declarations4.2.2 Variable declarations4.3V4.3.1g v244.3.2 Veclor net accessibility44.4 Strengths4.4.1 Charge strength4.4.2 Drive strength.....卓········中····“·········:·····················:········254.5 Implicit declarations4.6 Net types………264.6.1 Wire and tri nets264.6.2 Wired nets4.6.3TCopyright C 2006 IEEE. All rights reserved4.6.4 Trio and tri l nets4.6.5 Unresolved nets4.6.6 Supply nets324.7 Regs324.8 Integers, reals, times, and realtime4.8.1 Operators and real numbers4.8.2 Conversion4.9 Arrays4.9.1Net arrays…·中·····:··344.9.2 reg and variable arrays344.9.3 Memories4.10 Parameters…………………354.10.1 Module parameters…364.10.2 Local parameters(localparam““374.10.3 Specify parameters……384. Name spaces…39Expressions……5.1 Operators41Operators with real operands425.1.2 Operator precedence………5.1.3 Using integer numbers in expressions…….445.1.4 Expression evaluation order……2451. 5 Arithmetic operators5.1.6 Arithmetic expressions with regs and integers5. 1.7 Relational operators485.1.8Equ495.1.9 Logical operators…495.1.10 bitw isators505.1.11 Reduction operators5.112 Shift operators…….535. 1. 13 Conditional operator535.1. 14 Concatenations545.2 Operands………5.2. 1 Vector bit-Select and part-select addressing..565.2.2 Array and memory addressing.......,.……5.2.3ings585.3 Minimum, typical, and maximum delay expressions5.4 Expression bit lengths5.4.1 Rules for expression bit lengths65.4.2 Examole of expression bit-length problerpl635.4.3 Example of self-determined expressions.645.5 Signed expressions5.5.1 Rules for expression types.....5.5.2 Steps for evaluating5.5.3 Steps for evaluating an assignment5.54 Handling X and Z in signed expressions………5.6 Assignments and truncation6. Assignments……………686.1 Continuous assignments686. 1. 1 The net declaration assignment6.1.2 The continuous assignment statement·····中···:·:·4·中·····6.1.371Copyright C 2006 IEEE. All rights reserved
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单片机控制的太阳能充电器
单片机控制的太阳能充电器(硬件).单片机控制硬件电路设计中国矿业大学毕业设计任务书学院信电学院专业年级电气工程与自动化2005-1学生姓名ⅩXⅩ任务下达日期:2009年2月16日毕业设计日期:2009年2月16囗至2009年6月20口毕业设计题目:单片机控制的太阳能充电器(硬件)毕业设计专题题目:毕业设计主要内容和要求:(1)主观上能以认真的态度对待毕业设计;(2)能积极主动与教师联系;们n豆丁(3)具有较强的动手能力4)掌握太阳能电池板的工作原理和蓄电池充电方法5)掌握51系列单片机的使用;(6)完成 Protel制作的单片机控制的太阳能充电器的原理图;om7)完成与毕业设计内容有关的英文翻译(近三年的文献),不少于3000汉字;8)完成毕业设计论文。院长签字指导教师签字:摘要在污染和能源口趋紧张的背景下,太阳能作为一种新型的绿色可再生能源,具有储量大、利用经济、清洁环保等优点。因此,太阳能的利用越来越受到人们的重视。本文试图设计一种切实可行的太阳能充电控制器,通过对蓄电池充电,满足小功率的用户需求。本文重点研究了用AT89S52实现太阳能充电控制技术。详细介绍了100瓦太阳能电池板向12伏蓄电池充电的太阳能控制器硬件系统,包括系统的硬件电路设计、各部分电路的功能、工作原理和电子元器件型号的选取。硬件系统由直流稳压电源电路,AD实现对蓄电池端电压的动态监测及转换、AT89S52控制以及输出继电器开关电路四个部分组成,完成了整个太阳能充电控制器电路原理图的设计和制作。用 PROTEUS仿真软件进行了电路仿真,并且制作了相应的电路板但是由于时间关系,没能完成实物的实验测试。本文还对太阳能电池的结构原理、太阳能电池板的伏安特性、常用的铅酸蓄电池原理及工作情况作了详细介绍,并在此基础上介绍常用的蓄电池充电方法关键词:太阳能;蓄电池;充电控制:AT89S52;ADC0809godIn. comABSTRACTAgainst the background of energy shortage and its pollution, solar energy as a newkind of energy has a lot of advantages such as large reserves, economic, cleanliness andso on. So, people begin to pay more attention to the use of solar energy. The paperdesigns a feasible solar energy charging controller and storage batteries are charged tomeet the needs of low-power usersThis article focuses on the use of single-chip realization of solar charge controltechnology. 100-watt solar panels to 12-volt solar battery charge controller hardwaresystem is detailed, including system hardware circuit design, the various parts of thecircuit functions, working principles and models of selected electronic componentsHardware system is composed of four parts, which are DC regulated power supplycircuit, A/D to achieve on the battery terminal voltage of the dynamic monitoring andconversion, at89S52 relay control and output switching circuit. And finish the entiresolar charge controller circuit schematic design and production. PROTEUS Simulationwith circuit simulation software was accomplished, and a corresponding circuit boardwas produced. However, due to time constraints, failed to complete the kind ofexperimental test.In this paper, also the structure of the principle of solar cells, solar panels of theVolta metric characteristics of lead-acid batteries commonly used in the work ofprinciple was detailed, and the basis of methods commonly used on rechargeablebatteries was introducedKey words: solar; battery; charge control; AT89S52; ADC0809目录摘要…ABSTRACTi1绪论南·.非非。和着非和,着g非串,非串;自自非市非非非审库非非自非非着南。非非着,非自非非,非串;非非着非非串非非南非自非即自,自自自自非1.1课题研究背景1.1.1当前面临的能源和环境问题.…….1.1.2太阳能的开发和利用113光伏发电的特点12蓄电池充电系统121充电器的发展及其简单的类型1.22太阳能充电器123334513本课题研究的主要内容·::·:··中::;:丰中:·:·丰····和·丰2太阳能电池的研究和分析……21太阳能电池的原理22太阳能电池的分类623太阳能电池的等效电路中中++·+++··++++++++++··+·+·"+++++++;·+++++++++·++**+++++++++2.4太阳能电池板的输出特性及影响因素241光伏电池的主要参数…788242太阳的光照强度对光伏电池转换效率的影响24.3温度对光伏电池输出特性的影响10244本系统所采用的光伏电池.1125本章小结…123蓄电池133.1蓄电池的概念及其一般特性3.1.1电池的定义3.1.2主要参数指标133.1.3充放电特性11353.2铅酸蓄电池……....1632.1铅酸蓄电池的电极反应.…3.2.2铅酸蓄电池的充放电特性重重申自日非1833太阳能—蓄电池充电技术研究203.3.1恒流充电203.3.2恒压充电……:丰·;·中·421333恒压限流充电223.34两阶段、三阶段充电……123.35快速充电223.3.6智能充电2334本章小结·*+“··+**·*·中····*·“····234太阳能充电控制器的研究及设计…244.1太阳能充电器原理非自非·非申申着非非和自非非自非非非自非非自自自自着,申申非非非·自非非非非非非自着非非自非24411主控芯片的设计··········*···:·-·······+··244_1.2模数转换模块ADC0809简介*·“········*·中···**··+···2841.3电源模块的设计丰申丰丰中非丰:丰…30414分频器的设计3041.5外围电路的设计30416ADC0809与AT89S52接口,324.1.774LS00···:····申42单片机的防干扰技术··+++·+·+++··+·中+·“·+“+··+····+····+·+“·+++“·++·+“++++“··++·*····++354,2.1干扰分析··**·*·······*·····*··························**···**·*···**··········*····354,22硬件抗干扰方法3643系统的软件设计概述3744本章小结·甲····中·39结论…4.051全文工作总结aa,a,,aa,;,a,a,;a,aa。 nnnnnnn0nnnnnnnDnD,a,a;,a,,申;*。aaaa;a·4052进一步工作设想致谢重非南42参考文献43翻译部分.·“···中·“·45中文译文…··中+中··中···+···"·······45英文原文.1153www.docin.com中国矿业大学2009届本科生毕业设计第1页1绪论1课题研究背景11前面临的能源和环境问题1234能源犹如人体的血液。能量以电的形式出现,是现代社会文明的重要标志和基础,“电力技术是通向可持续发展的桥梁”这个论断已经成为共识。人们总是尽可能把一次能源转换为电能使用,电力在终端能源中的比例正在不断提高。但是随着电能利用比例的提高,也带来了很多的问题。方面,用于发电的传统一次能源如煤、石油等的储藏量有限。随着经济的发展、人口的增加,目前人类所利用的石油、天然气和煤炭等化石能源正在逐步消耗,能源危机已经展现在人类面前。根据目前所探明的储量和消费量计算,石油可用40多年,天然气可用60多年,煤可用200年左右。中国的能源资源储量情况更是危机逼人,中国各种一次能源资源均低于世界平均水平,中国的能源需求面临着更严重的挑战。国家1999年政府白皮书估计,目前我国石油可供开采20年;天然气可供开采60年;煤炭剩余量稍显富裕,但可供开采不足百年。而且随着科技的进一步发展、人口的持续增长等,整个世界面临着能源需求量成倍增长的挑战。另一方面,成倍的能源供应的背后蕴藏着巨大的危害,并且其影响越来越大,这就是由此带来的环境问题。当前,化石燃料的燃烧已经给人们的生活环境带来严重的挑战:大气中的颗粒物和二氧化硫浓度增高,由此带来的直接灾难就是酸雨,在严重被污染的大气中人类和其他生物的健康遭受着痛苦的折磨:大量碳化物的燃烧使得大气中的二氧化碳浓度持续增加,温室效应越趋明显,并且这种势头正在延续,由此带来的直接灾难就是大气变暖、水平面上升等。这种由环境污染衍生的环境效应具有滞后性,往往在污染发生的当时不容易被察觉或预料到,然而一旦发生就表示环境污染已经发展到相当严重的地步。环境污染所带来的最直接、最容易被人们所感受的后果就是使人类环境的质量下降,影响人类的生活质量、身体健康和生产活动。如不采取积极措施,保护生态环境,将会严重威胁到人类社会的生存空间。随着经济和贸易的全球化,环境污染也日益呈现国际化趋势。因此,无论是从确保长期的能源供应,还是从保护环境的角度岀发,开发利用取之不竭而又没有公害的新能源己是势在必行。由此在开发和使用能源的同时,保护好人类赖以生存的地球环境与生态已经成为一个全球性的重要问题。因此节约能源、发展清洁干净的新能源和再生能源是势在必行的。12太阳能的开发和利用42学209届本科生毕业设计中国矿业大第2页正如上面所说的一样,能源是人类社会赖以生存和发展的物质基础,21世纪是世界能源结构发生巨大变革的世纪。当前,包括我国在内的绝大多数国家都以石油、天然气和煤炭等矿物燃料为主要能源。随着矿物燃料的日益枯竭和全球环境的不断恶化,传统能源(如煤、石油、天然气等)的供给已出现严重短缺局面,人类开始将目光转向可再生能源的发展。大规模地开发利用可再生洁净能源,以资源无限、清洁干净的可再生能源为主的多样性的能源结构代替以资源有限、污染严重的石化能源为主的能源结构己成为人们关注的焦点。虽然在可预见的将来,煤炭、石油、天然气等矿物燃料,仍将在世界能源结构中占有柑当的比重,但人们对核能以及太阳能、风能、地热能、水力能、生物能等可再生能源资源的利用日益重视,在整个能源消耗中所占的比例正在显著地提高。在未来的一段时间内,可再生能源将能够与矿物燃料相抗衡,从而结束矿物燃料一统天下的局面。其中,可再生能源主要有以下几个方面:①太阳能:据天文物理学家的计算表明,太阳系还能存在45亿年,太阳每年辐射到地球的总能量相当于人类能源消耗的1.2万倍。②氢能源:利用自然界大量存在的水,由电解水产生氢,或者由太阳能光催化水分解氢。③风力发电、小水电与潮汐发电:可提供可观的电力。④生物能:包括城市垃圾的转化、人类粪便的转化等。这些能源原本是人类的废弃物所转化过来的,只要有人类的存在,就会有生物能,所以这种能源也可以说是用之不竭的。⑤核能:与传统能源的发电厂相比,核能的利用率较高,对环境的污染小,并且使用核燃料的成本远远低于传统燃料的成本,而核燃料所释放岀来的能量却远远高于传统能源所释放出来的能量。其中,太阳能作为一种新型的绿色可再生能源,与其他新能源相比利用最大,是最理想的可再生能源。特别是近几十年来,随着科学技术的不断进步,太阳能及其相关产业成为世界发展最快的行业之一。因为它具有以下的特点:①存储量巨大:太阳能是取之不尽的可再生能源,可利用量巨大。太阳放射的总辐射能量大约是375×1030W,是极其巨大的。其中到达地球的能量高达173×104KW,穿过大气层到达地球表面的太阳辐射能大约为81×103KW。在到达地球表面的太阳辐射能中,到达地球陆地表面的辐射能大约为17×103w,相当于目前全世界一年内消耗的各种能源所产生的总能量的三万五千多倍。太阳的寿命至少尚有40亿年,相对于人类历史来说,太阳可源源不断供给地球能源的时间可以说是无限的。中国矿业大学2009届本科生毕业设计第3页②取之不尽,不需要开采和运输。③清洁无污染,无任何物质的排放,既不会留下污染物,也不会向大气中排放废气。113光伏发电的特点1443太阳能利用可分为热利用和光伏发电两种方式,热利用主要在采暖领域多,形式比较单一;而光伏发电可以把太阳能转换为当今最普遍的能源利用形式电能,从而具有热利用不可比拟的优势。太阳能发电又分为光电发电、光化学发电、光感应发电和光生物发电。光伏发电是利用光伏电池这种半导体器件吸收太阳光辐射,使之转化成电能的直接发电形式,光伏发电当今太阳能发电的主流。与常规发电和其他绿色发电技术相比,光伏发电系统具有如下的优势:①是真正的无污染排放、不破坏环境的可持续发展的绿色能源。太阳能不用燃料,运行成本很小,并且发电部件不易损坏,维护简单;②利用的场合广泛和灵活,既可以独立于电网运行,也可以与电网并行运行;③可作为电力用户供电可靠或提高电能质量的不停电电源;④接近负载中心,减少电网的线损;⑤发电的效率不随发电规模的大小而变;⑥就地可去,无需运输。光伏发电系统建设周期短,由于是模块化安装,不仅可用于小到太阳能计算器的几个毫伏,大到数十兆瓦的光伏电站,而且可以根据负荷的增减,任意添加或减少太阳电池容量,既方便灵活,又避免了浪费。由于太阳能存在上述的优势,光伏发电在世界范围內受到高度的重视,发展很快。但是,目前光伏发电与电网供电的比较,光伏发电价格还比较高,不过其维修费用很少,随着发电量的增加,其价格会下降,优势才逐渐体现出来12蓄电池充电系统2-3121充电器的发展及其简单的类型充电方式的选择直接影响着电池的使用效率和使用寿命,充电技术近年来发展非常迅速。充电器的发展经历了三个阶段限流限压式充电器最原始的就是限压式充电,然后过渡到限流限压式充电,它使用的方式就是浅充浅放,其寿命表述就是时问间,没有次数,比如10年。这种充电模式的效果较差②恒流限压式充电器
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