有关自动化专业的英文论文题目

用于分布式在线UPS中的并联逆变器的一种无线控制器A Wireless Controller for Parallel Inverters in Distributed Online UPS SystemsJosep M. Guerrero', Luis Garcia de Vicufia", Jose Matas'*, Jaume Miret", and Miguel Castilla". Departament #Enginyeria de Sistemes, Automatica i Informhtica Industrial. Universitat Polithica de CatalunyaC. Comte d'Urgell, 187.08036 -Barcelona. Spain. Email: .. Departament #Enginyeria Electrbnica. Universitat Polit6cnica de CatalunyaAV. Victor BaLguer s/n. 08800I - Vilanova i la Geltrh. SpainAbsiract - In this paper, a novel controller for parallelconnectedonline-UPS inverters without control wireinterconnections is presented. The wireless control technique isbased on the well-known droop method, which consists inintroducing P-oand Q-V schemes into the inverters, in order toshare properly the power drawn to the loads. The droop methodhas been widely used in applications of load sharing betweendifferent parallel-connected inverters. However, this methodhas several drawbacks that limited its application, such as atrade-off between output-voltage regulation and power sharingaccuracy, slow transient response, and frequency and phasedeviation. This last disadvantage makes impracticable themethod in online-UPS systems, since in this case every modulemust be in phase with the utility ac mains. To overcome theselimitations, we propose a novel control scheme, endowing to theparalleled-UPS system a proper transient response, strictlyfrequency and phase synchronization with the ac mains, andexcellent power sharing. Simulation and experimental resultsare reported confirming the validity of the proposed approach.1. INTRODUCTIONThe parallel operation of distributed Uninterruptible PowerSupplies (UPS) is presented as a suitable solution to supplycritical and sensitive loads, when high reliability and poweravailability are required. In the last years, many controlschemes for parallel-connected inverters has been raised,which are derived from parallel-schemes of dc-dc converters[I], such as the master-slave control [2], or the democraticcontrol [3]. In contrast, novel control schemes have beenappeared recently, such as the chain-structure control [4], orthe distributed control [ 5 ] . However, all these schemes needcontrol interconnections between modules and, hence, thereliability of the system is reduced since they can be a sourceof noise and failures. Moreover, these communication wireslimited the physical situation ofthe modules [6].In this sense, several control techniques has been proposedwithout control interconnections, such as the droop method.In this method, the control loop achieves good power sharingmaking tight adjustments over the output voltage frequencyand amplitude of the inverter, with the objective tocompensate the active and reactive power unbalances [7].This concept is derived from the power system theory, inwhich the frequency of a generator drops when the powerdrawn to the utility line increases [8].0-7803-7906-3/03/$17.00 02003 IEEE. 1637However, this control approach has an inherent trade-offbetween voltage regulation and power sharing. In addition,this method exhibits slow dynamic-response, since it requireslow-pass filters to calculate the average value of the activeand reactive power. Hence, the stability and the dynamics ofthe whole system are hardly influenced by the characteristicsof these filters and by the value of the droop coefficients,which are bounded by the maximum allowed deviations ofthe output voltage amplitude and frequency.Besides, when active power increases, the droopcharacteristic causes a frequency deviation from the nominalvalue and, consequently, it results in a variable phasedifference between the mains and the inverter output voltage.This fact can be a problem when the bypass switch mustconnect the utility line directly to the critical bus in stead ofits phase difference. In [9], two possibilities are presented inorder to achieve phase synchronization for parallel lineinteractiveUPS systems. The first one is to locate a particularmodule near the bypass switch, which must to synchronizethe output voltage to the mains while supporting overloadcondition before switch on. The second possibility is to waitfor the instant when phase matching is produced to connectthe bypass.However, the mentioned two folds cannot be applied to aparallel online-UPS system, since maximum transfer timeought to be less than a % of line period, and all the modulesmust be always synchronized with the mains when it ispresent. Hence, the modules should be prepared to transferdirectly the energy from the mains to the critical bus in caseof overload or failure [lo].In our previous works [11][12], we proposed differentcontrol schemes to overcome several limitations of theconventional droop method. However, these controllers bythemselves are inappropriate to apply to a parallel online-UPS system. In this paper, a novel wireless control scheme isproposed to parallel different online UPS modules with highperformance and restricted requirements. The controllerprovides: 1) proper transient response; 2) power sharingaccuracy; 3) stable frequency operation; and 4) good phasematching between the output-voltage and the utility line.Thus, this new approach is especially suitable for paralleled-UPS systems with true redundancy, high reliability andpower availability. Simulation and experimental results arereported, confirming the validity of this control scheme.Fig. 1. Equivalenl cimuif ofan invener connecled 10 a bust"Fig. 2. P-odraop function.11. REVlEW OF THE CONVENTIONAL DROOP METHODFig. 1 shows the equivalent circuit of an inverter connectedto a common bus through coupled impedance. When thisimpedance is inductive, the active and reactive powers drawnto the load can be expressed asEVcosQ - V2 Q=where Xis the output reactance of an inverter; Q is the phaseangle between the output voltage of the inverter and thevoltage of the common bus; E and V are the amplitude of theoutput voltage of the inverter and the bus voltage,respectively.From the above equations it can be derived that the activepower P is predominately dependent on the power angle Q,while the reactive power Q mostly depends on the outputvoltageamplitude. Consequently, most of wireless-control ofparalleled-inverters uses the conventional droop method,which introduces the following droops in the amplitude Eand the frequency U of the inverter output voltageu = w -mP (3)E = E ' - n Q , (4)being W* and E' the output voltage frequency and amplitudeat no load, respectively; m and n are the droop coefficientsfor the frequency and amplitude, respectively.Furthermore, a coupled inductance is needed between theinverter output and the critical bus that fixes the outputimpedance, in order to ensure a proper power flow. However,it is bulky and increase:; the size and the cost of the UPSmodules. In addition, tho output voltage is highly distortedwhen supplying nonlinezr loads since the output impedanceis a pure inductance.It is well known that if droop coefficients are increased,then good power sharing is achieved at the expense ofdegrading the voltage regulation (see Fig. 2).The inherent trade-off of this scheme restricts thementioned coefficients, which can be a serious limitation interms of transient response, power sharing accuracy, andsystem stability.On the other hand, lo carry out the droop functions,expressed by (3) and (4), it is necessary to calculate theaverage value over one line-cycle of the output active andreactive instantaneous power. This can be implemented bymeans of low pass filters with a smaller bandwidth than thatof the closed-loop inverter. Consequently, the powercalculation filters and droop coefficients determine, to a largeextent, the dynamics and the stability of the paralleledinvertersystem [ 131.In conclusion, the droop method has several intrinsicproblems to be applied 1.0 a wireless paralleled-system ofonline UPS, which can he summed-up as follows:Static trade-off between the output-voltage regulation(frequency and amplitude) and the power-sharingaccuracy (active an4d reactive).2) Limited transient response. The system dynamicsdepends on the power-calculation filter characteristics,the droop coefficients, and the output impedances.Lost of ac mains synchronization. The frequency andphase deviations, due to the frequency droop, makeimpracticable this method to a parallel-connectedonline UPS system, in which every UPS should becontinuously synchronized to the public ac supply.1)3)111. PROPOSED CONTROL FOR PARALLEL ONLINE UPSINVERTERSIn this work, we will try to overcome the above limitationsand to synthesize a novel control strategy withoutcommunication wires that could be appropriate to highperformanceparalleled industrial UPS. The objective is toconnect online UPS inverters in parallel without usingcontrol interconnections. This kind of systems, also namedinverter-preferred, should be continuously synchronized tothe utility line. When an overload or an inverter failureoccurs, a static bypass switch may connect the input line tothe load, bypassing the inve:rter [14][15].Fig. 3 shows the general diagram of a distributed onlineUPS system. This system consists of two buses: the utilitybus, which is connected lo the public ac mains; and thesecure bus, connected to the distributed critical loads. Theinterface between these buses is based on a number of onlineUPS modules connected in parallel, which providescontinuously power to the: loads [16]. The UPS modulesinclude a rectifier, a set of batteries, an inverter, and a staticbypass switch.11638Q ac mainsutility busI I Ij distributed loads !Fig. 3. Online distributed UPS system.syposr /I 4(4Fig. 4. Operation modes of an online UPS.(a) Normal operation. (b) Bypass operation. (c) Mains failureThe main operation modes of a distributed online UPS1) Normal operation: The power flows to the load, fromthe utility through the distributed UPS units.2) Mains failure: When the public ac mains fails, theUPS inverters supply the power to the loads, from thebatteries, without disruption.Bypass operation: When an overload situation occurs,the bypass switch must connect the critical busdirectly to the ac mains, in order to guarantee thecontinuous supply of the loads, avoiding the damageof the UPS modules.For this reason, the output-voltage waveform should besynchronized to the mains, when this last is present.system are listed below (see Fig. 5):3)Nevertheless, as we state before, the conventional droopmethod can not satisfy the need for synchronization with theutility, due to the frequency variation of the inverters, whichprovokes a phase deviation.To obtain the required performance, we present a transientP-w droop without frequency-deviation in steady-state,proposed previously by OUT in [ 111w=o -mP (5)where is the active power signal without the dccomponent,which is done by. -I t -1sP= p ,( s + t - ' ) ( s + o , )being zthe time constant of the transient droop action.The transient droop function ensures a stable frequencyregulation under steady-state conditions, and 'at the sametime, achieves active power balance by adjusting thefrequency of the modules during a load transient. Besides, toadjust the phase of the modules we propose an additionalsynchronizing loop, yieldingo=w'-m%k,A$, (7)where A$ is the phase difference between the inverter and themains; and k, is the proportional constant of the frequencyadjust. The steady-state frequency reference w* can beobtained by measuring the utility line frequency.The second term of the previous equality trends to zero insteady state, leading tow = w' - k4($ -@'), (8)being $and $* the phase angles of the output voltage inverterand the utility mains, respectively.Taking into account that w = d $ / d t , we can obtain thenext differential equation, which is stable fork, positived$ *dt dt- + km$ = - + k,$' . (9)Thus, when phase difference increases, frequency willdecrease slightly and, hence, all :he UPS modules will besynchronized with the utility, while sharing the power drawnto the loads.IV. CONTROLLIEMRP LEMENTATIONFig. 5 depicts the block diagram of the proposedcontroller. The average active power P , without the dccomponent, can be obtained by means of multiplying theoutput voltage by the output current, and filtering the product........................................................................................io",.LSj'nchronirorion loop.......................................................................................Fig. 5. Block diagram of the proposed controller.using a band-pass filter. In a similar way, the averagereactive power is obtained, hut in this case the output-voltagemust be delayed 90 degrees, and using a low-pass filter.In order to adjust the output voltage frequency, equation(7) is implemented, which corresponds to the frequencymains drooped by two transient-terms: the transient activepower signal term; and the phase difference term, whichis added in order to synchronize the output voltage with theac mains, in a phase-locked loop (PLL) fashion. The outputvoltageamplitude is regulated by using the conventionaldroop method (4).Finally, the physical coupled inductance can be avoided byusing a virtual inductor [17]. This concept consists inemulated an inductance behavior, by drooping the outputvoltage proportionally to the time derivative of the outputcurrent. However, when supplying nonlinear loads, the highordercurrent-harmonics can increase too much the outputvoltageTHD. This can be easily solved by using a high-passfilter instead of a pure-derivative term of the output current,which is useful to share linear and nonlinear loads [I 1][12].Furthermore, the proper design of this output inductance canreduce, to a large extent, the unbalance line-impedanceimpact over the power sharing accuracy.v. SIMULATION AND EXPERIMENTARELS ULTSThe proposed control scheme, (4) and (7), was simulatedwith the parameters listed in Table 1 and the scheme shownin Fig. 6, for a two paralleled inverters system. Thecoefficients m, n, T, and kv were chosen to ensure stability,proper transient response and good phase matching. Fig. 7shows the waveforms of the frequency, circulating currents,phase difference between the modules and the utility line,and the evolution of the active and reactive powers. Note theexcellent synchronization between the modules and theACmiiinr 4 j. ...L...I.P...S...1... ..........................B...u...n...r.r..r..e..s... ................................... iFig. 6. Parallel operation oftwa online UPS modules,mains, and, at the same time, the good power sharingobtained. This characteristik let us to apply the controller tothe online UPS paralleled systems.Two I-kVA UPS modules were built and tested in order toshow the validity of the proposed approach. Each UPSinverter consisted of a single-phase IGBT full-bridge with aswitching frequency of 20 kHz and an LC output filter, withthe following parameters: 1. = 1 mH, C = 20 WF, Vi" = 400V,v, = 220 V, I50 Hz. The controllers of these inverters werebased on three loops: an inner current-loop, an outer PIcontroller that ensures voltage regulation, and the loadsharingcontroller, based on (4) and (7). The last controllerwas implemented by means of a TMS320LF2407A, fixedpoint40 MHz digital sigrial processor (DSP) from TexasInstruments (see Fig. 8), using the parameters listed in TableI. The DSP-controller also includes a PLL block in order tosynchronize the inverter with the common bus. When thisoccurs, the static bypass switch is tumed on, and the droopbasedcontrol is initiated.1640big 7 Wa\cfc)rms for twu.invencr, ;mnectcd in parallel. rpchrontred io Ihc ac mdnl.(a) Frequencics ufhoth UPS (b) Clrculattng currcni among modulcs. (CJ Phmc d!Nercn;: betucen ihc UPS a#>dth e ai mum(d) Ikiril uf the phze diNmncc (e) md (0 Activc and rcactlw pouerr "I ooih UPSNote that the iimc-acs arc deliheratcly JiNercni due in thc disiinct timuion*uni) ofthe \ inrblrr1641TABLEI.PARAMETEROSF THE PARALLELESDYS TEM.Filter Order I IFilter Cut-off Frequency I 0, I 10 I ragsFig. 8 shows the output-current transient response of theUPS inverters. First, the two UPS are operating in parallelwithout load. Notice that a small reactive current is circlingbetween the modules, due to the measurement mismatches.Then, a nonlinear load, with a crest factor of 3, is connectedsuddenly. This result shows the good dynamics and loadsharingof the paralleled system when sharing a nonlinearload.Fig. 8. Output current for the two paralleled UPS, during the connection of Bcommon nonlinear load with a crest factor of 3. (Axis-x: 20 mddiv. Axis-y:5 Mdiv.).VI. CONCLUSIONSIn this paper, a novel load-sharing controller for parallelconnectedonline UPS systems, was proposed. The controlleris based on the droop method, which avoids the use ofcontrol interconnections. In a sharp contrast with theconventional droop method, the controller presented is ableto keep the output-voltage frequency and phase strictlysynchronized with the utility ac mains, while maintaininggood load sharing for linear and nonlinear loads. This fact letus to extend the droop method to paralleled online UPS.On the other hand, the proposed controller emulates aspecial kind of impedance, avoiding the use of a physicalcoupled inductance. Th.e results reported here show theeffectiveness of the proposed approach.

不会写论文还这么嚣张?不就是250分吗得到了又怎么地？能吃呀？

Welding Automation Research in the engineering school is largely focused on problems involving sensing, modeling, and control of welding processes, i.e., welding automation. Faculty and students from electrical engineering, mechanical engineering, and material science are involved in the welding automation research. The overall objective of this research is to provide both greater productivity and enhanced quality for welding in the manufacturing environment.http://eecs.vanderbilt.edu/researchgroups/weldingautomation

这个不能复制过来的啊，你在百度知道搜索一下就知道了啊

用于分布式在线UPS中的并联逆变器的一种无线控制器已经发送。

不管是导师还是读者，评判论文的第一感是先审核题目，选题是撰写论文的奠基工程，在一定程度上决定着论文的优劣。下面我给大家带来2022英语教学论文题目选题参考整理，希望能帮助到大家!

▼▼目录▼▼

本科英语教学论文题目

英语教育论文题目大全

英语教育硕士毕业论文题目

●  本科英语教学论文题目

1、 浅析新建本科院校英语社团建设

2、 地方本科高校英语专业人才培养质量发展性评价探析

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4、 新建应用型本科院校英语课堂沉默现象成因及应对策略

5、 应用型本科高校大学英语教学改革的定位策略

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8、 本科翻译专业“英语经典原着深阅读”实践模式探讨

9、 关于地方新建本科院校应用型英语翻译人才培养模式的思考

10、 基于供需平衡理论对辽宁本科英语翻译专业发展问题的必要性研究

11、 英语专业本科毕业论文学术失范现象的成因与对策

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16、 新建本科院校学生英语课程形成性评价对自主学习能力培养的研究

17、 后殖民文学在本科英语专业的教学探索

18、 高校商务英语本科专业实践教学体系构建的逻辑基础

19、 地方本科院校大学英语转型期翻转课堂混合式教学设计

20、 本科英语教学中的学生创新素质培养研究

21、 本科高校学生大学英语自主学习能力调查与分析

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31、 应用型本科自动化 专业英语 课程教改研究

32、 应用型本科院校化工专业英语 教学 方法 探索

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35、 转型发展背景下新建本科院校应用导向的英语专业复合型人才培养模式研究

36、 美国“5C”标准下的大学英语教学改革--以山西新晋本科院校为例

37、 地方高校本科英语专业口译人才培养模式的创新研究

38、 新建本科院校大学生英语需求分析

39、 应用型商务英语本科人才培养理念下的“生态化”商务单证教学浅析

40、 本科优秀英语习作者元认知能力及其表征：个案分析

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43、 应用型本科高校大学英语教改成效及修正策略

44、 教学型师范院校英语本科教学技能培养提升路径

45、 地方省属本科院校大学英语教学模式改革探析

46、 大学英语读写中的语块运用研究--以地方本科院校为例

47、 探讨以市场需求为导向的英语专业本科翻译教学改革

48、 应用型本科院校职校生源与普高生源学生英语学习动机比较研究

49、 独立本科院校商务英语课程形成性评价对学生自主学习能力培养的研究

50、 本科职业教育背景下大学英语教师面临的挑战与 反思

51、 应用型英语专业本科人才培养的目标与体系构建

52、 应用型本科背景下英语专业师范生培养途径探索

53、 市属本科院校英语专业学生就业核心竞争力培养策略探析

54、 英语专业本科毕业论文“精细化”指导“六步”模式探索

55、 英语本科毕业论文评估主体应有的职业道德

56、 地方本科院校英语专业多元化实践教学体系设计

57、 地方农林类本科院校推广全英语教学的困境与出路

58、 医药类本科院校生物工程专业英语教学探索与实践

59、 慕课背景下应用型本科院校大学英语教师面临的机遇与挑战

60、 地方本科院校商务英语专业实践教学体系构建研究

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●   英语教育论文题目大全

浅探幼儿英语语音教学的有效方法

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一对一数字化环境下的小学低段 英语 故事 阅读教学实践--以牛津英语幼儿故事“Books!”为例

关键期假设视角下的幼儿英语教育目标定位

全语言教学在幼儿英语教学中的应用

河北省幼儿英语师资现状调研及分析

幼儿英语学习的兴趣导向及培养

高校《幼儿英语教育》课程改革探究

民族地区农村幼儿英语教师培养策略研究--以湘西土家族苗族自治州为例

英语 儿童 绘本译作与中国幼儿文学的语言对比研究

浅谈幼儿英语教学的三个原则

幼儿英语教学之理性思考

中美幼儿英语教育方法的比较分析

父母期待对幼儿英语学习行为的影响分析

幼儿英语教学师资力量与学习效率的关系探讨

浅谈幼儿英语的教学方法

技能型学前教育专业幼儿英语师资培养研究

大连市幼儿英语教育的现状分析及建议

游戏教学在幼儿英语教学中的应用

探究幼儿英语学习兴趣的培养模式

新课改视野下的幼儿英语教学初探

民办教育培训机构中幼儿英语教育的现状与问题研究--以河南省Z市J区为例

从整合教育的角度分析幼儿学前英语教育

活动教学法与幼儿英语教学的有效整合

校企合作共建区域幼儿英语师资培养机制

根据幼儿心理特点，探析英语教学方法

幼儿英语语音意识发展中教师多元角色的构建

幼儿英语课程改革的探究

幼儿教师 英语口语 构成研究

游戏教学法在幼儿英语教学中的角色及运用

试谈幼儿英语教学方法

培养幼儿师范学生的 英语写作 习惯漫谈

英语词汇类APP在幼儿英语学习中的应用研究

浅谈如何激发幼儿 学习英语 的兴趣

幼儿英语教育中的“游戏”教学法研究

现代信息技术在幼儿英语教学中的应用策略

浅谈英语浸入式下幼儿语言的发展

幼儿英语教师教学能力现状及提升途径

浅谈幼儿英语语音意识的培养

幼儿教师英语口语构成研究

幼儿英语课程改革的探究

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●   英语教育硕士毕业论文题目

1、基础教育国际化进程中混班就读外籍学生的教育图景

2、从“能力本位”到“表现标准本位”

3、大学英语教师个人通识教育信念研究

4、基础教育英语教师教学能力及其发展研究

5、中国聋校英语教育：教学体系的构建

6、多元互动英语教师校本教育模式：理论与实践

7、蒙汉双语教育背景下蒙古族学生英语学习研究

8、大学外语教育的理论与实践探索

9、继续教育英语专业学生听说能力培养行动研究

10、面向 文化 理解的英语专业教育

11、引导智慧生成的大学英语教育研究

12、美国关键语言教育政策的战略演变

13、教育隐喻的文化认知研究

14、教育实习对英语教育硕士教师信念的影响研究

15、英语教育硕士实习生教师自我效能感研究

16、乌鲁木齐市中学少数民族双语班英语教育现状调查研究

17、中学生英语 学习态度 与情感教育研究

18、高中英语教学中人文素养教育现状调查与改进策略

19、英语教育硕士项目的实效及改进策略研究

20、国外MOOC视频在专业英语视听教学中的应用研究

21、英语浸入式环境下学前儿童家庭英语教育的实践研究

22、《K-12STEM教育通用评估体系》翻译 报告

23、教育实习对新手教师身份认同的影响

24、初中英语教师对英语教育工具性与人文性双重属性的理解

25、基于岗位导向的英语教学改革研究

26、教育游戏软件在小学英语教学中的应用研究

27、初中英语教学中的审美教育

28、初中英语课堂上落实情感教育目标状况的调查研究

29、赏识教育在中等职业学校英语教学中的应用

30、小学英语教育游戏的设计与应用

31、探析能力本位教育在高职英语教学改革中的应用

32、中小学英语教学中的文化教育研究

33、英语国际化形势下中国英语教育发展史研究

34、在英语师范教育课程中培养学科教学知识

35、我国大学英语教育功能定位反思

36、小学英语教育专业英语语音教学个案研究

37、教育游戏在小学英语教学中的应用研究

38、通识教育视野下我国大学外语课程改革研究

39、大学英语教学中情感教育的有效性研究

40、教育游戏在英语教学中的应用研究

41、新教传教士与晚清英语教育

42、以合作学习为途径在英语教学中实施国际理解教育的行动研究

43、英美职前教师教育实习之比较研究

44、教育游戏在小学英语教学中的应用研究

45、论汉英翻译中的“中式英语”及翻译对策

46、情感教育理论在小学英语教学中的应用研究

47、贵州农村地区中学英语教育观察

48、大学英语通识教育化探索

49、从批评话语分析视角分析中美媒体对中国基础教育改革的报道

50、养成教育中学习习惯的培养对英语学习的影响

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