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, -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 . 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 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/$ 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 , 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 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 , 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 , 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 . 1. Equivalenl cimuif ofan invener connecled 10 a bust"Fig. 2. P-odraop . 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, 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, , 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 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 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 [ conclusion, the droop method has several intrinsicproblems to be applied 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 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 )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 ac mainsutility busI I Ij distributed loads !Fig. 3. Online distributed UPS /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 ) Mains failure: When the public ac mains fails, theUPS inverters supply the power to the loads, from thebatteries, without 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 this reason, the output-voltage waveform should besynchronized to the mains, when this last is 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 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 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 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, 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 . 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 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 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 . 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...... ..........................B...u...n...... ................................... 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 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 7 Wa\cfc)rms for , ;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 \ THE PARALLELESDYS 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 , 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 . 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 the other hand, the proposed controller emulates aspecial kind of impedance, avoiding the use of a physicalcoupled inductance. results reported here show theeffectiveness of the proposed approach.
机械制造行业是我国经济的支柱性产业,机械制造行业对经济的发展具有巨大的推动作用,随着现代科技的不断发展,机械制造自动化技术也在不断的进步,并且逐渐的向自动化和精密化方向发展。下文是我为大家搜集整理的关于机械制造与自动化论文参考范文的内容,欢迎大家阅读参考!
浅析机械制造与自动化技术
摘 要:机械制造是我国国民生产经济中的基础产业,该行业的发展对于其他行业的发展具有十分重要的影响。随着自动化技术的不断普及,机械制造与自动化技术的结合也将成为必然发展趋势。机械制造行业将在自动化技术的推动下,逐渐实现虚拟化、智能化的转变,从而帮助企业实现节能减排的生产目标,提高企业经济效益。
关键词:机械制造;自动化技术;虚拟化;智能化
1 概述
机械制造技术是我国国民生产经济中的重要基础产业之一,主要致力于机械产品的设计、加工制造、生产、维修等一系列流程的工程学科。随着经济的不断发展,社会各行业对机械制造技术的需求量不断增加,其规模及速度得到前所未有的发展,同时也给环境带来了极大的危害。为保障机械制造业的可持续发展,利用先进的自动化技术提高机械制造的生产效率,降低成本,减少排放成为各企业竞相追求的目标。
2 自动化技术
自动化技术是人类为解放劳动力而采用机械或者其他工具代替人类劳动的一项发明,通过机械或者工具能自主完成既定的工作任务,以达到减轻人类劳动负担的目的。随着科学技术的不断发展,尤其是计算机与互联网技术的大力发展及广泛普及,现代自动化的概念已经扩展至利用任何机械或者工具来取代人类劳动的范畴。现代自动化技术的涵义相对于传统自动化技术而言,已经有了更多的内容。从自动化技术的功能方面来看,自动化技术代替人类工作只是功能的一小部分,其最终目的是构建一个有机的体系,通过该体系的建立可以协调和优化人类与机器的关系,实现人类生活与工作智能化的目标;从表现形式上看,现代自动化技术可代替人类劳动,代替或者辅助人类的各项工作,协调或者管理生产系统中的部分工作或整个工作系统;从应用范围来看,现代自动化技术不仅应用于具体的生产行业,还可广泛应用于众多的中间产业,甚至是人类的生活。
3 机械制造与自动化技术的结合
机械制造业的发展需要自动化技术
①机械制造企业管理落后。
计算机及互联网技术的发展,使得发达国家的机械制造企业在管理方面也优于我国。发达国家企业将计算机运用到企业管理当中,改变了企业的生产模式和组织管理方式,为实现精益生产、准时生产、高效生产的全新的管理思想的实现提供了有力的制度保障;我国进入信息化时代较晚,计算机普及速度虽然较快,但利用计算机管理企业生产的应用情况并不理想。
②机械制造技术落后。
发达国家经历了蒸汽时代和电气时代的两次改革浪潮后,传统的机械制造工艺已经发展至较为成熟的阶段,且机械制造业的高速发展期也高于我国;目前,发达国家已经将纳米技术、复合型加工技术和微激光加工技术普及到机械制造技术当中,大大提高了机械制造的效率。相对于西方发达国家的机械制造技术,我国的制造工艺处于落后阶段,大部分制造企业仍采用农间作坊的生产模式;现代化水平低且应用范围十分有限,尖端技术尚处于不成熟的研发当中。
③机械制造自动化程度低。
发达国家机械制造企业已经将计算机集成技术、自动化数控技术和柔性制造系统广泛应用于机械制造业当中,实现了机械制造生产的自动化、集成化和智能化;而我国大部分私有企业的机械制造的自动化技术刚处于初步使用阶段,生产过程中仍以人工管理为主;柔性制造系统仅在少数大型企业中采用。
机械制造自动化技术未来发展趋势
①机械制造的虚拟化。
网络制造技术是利用计算机仿真模拟软件,在模拟的操作环境中对虚拟对象进行各项技术操作,通过对虚拟产品设计、制造过程的模拟,预测该产品的性能及生产成本,以实现企业生产系统中设定的高质量、高性能、低成本的目标。首先,网络技术为企业发展提供了强大的技术支持。企业可通过虚拟的网络软件对各种工程或者产品进行虚拟制造,减少不同部门人员之间交流限制,大大方便了后续的交流与合作。其次,网络虚拟软件能模拟销售过程,利用该功能和检验产品的销售状况。若模拟结果不理想,企业可通过修改实验参数数据来改变实验条件,重新对产品进行模拟销售,以完善实验结果。利用网络虚拟软件,不仅可以节约设计时间,还能有效降低实验成本,减少企业的成本支出。
②机械制造智能化。
人工智能是由人和机械组成的复杂性系统,通过人与机器设备的合作实现机械制造过程。人工劳动在一定程度上存在某种缺陷性或局限性,这就限制了机械制造业的发展。而随着科技的进步,机械制造与自动化技术的结合将使制造工作向人工智能方向转变。智能化制造系统在制造过程中,可以通过分析、判断、构思等一系列智能化活动,提高机械制造的适应性和友好性。该系统具有良好的柔性,减少了机械制造过程中对资源的消耗和浪费。随着社会各行业对机械制造需求的提升,仅靠人力劳动已经无法满足社会的需求,而人工劳动与机器制造的组合方式可大力提高生产效率,满足社会对机械制造的需求。人工智能的出现可降低人工的工作强度,从而为拓展人力在机械制造中的应用提供了可能;另外,人工智能的广泛应用有助于人类智能的延伸,使人将更多的精力用于创造性的活动当中,从而产生更多具有价值的成果;最后,人工智能能完成人工无法完成的部分危险性工作,改善了人工的工作环境。
③机械制造环保化。
机械制造业大力发展的同时,由于制造工艺的落后,不仅造成了极大的资源浪费,还给环境带来极为严重的危害,引起了社会的各界关注。机械制造与自动化技术的结合,将有效减少资源的浪费及污染物的排放,从而提高行业的环保程度,为制造业的健康发展提供必要保障。自动化技术在机械制造中的应用,能有效提高生产效率,减少资源浪费,提高企业的经济效益和社会效益。
4 总结
机械制造与自动化技术的结合是必然的发展趋势,利用自动化技术,机械制造企业可实现生产过程的虚拟化、智能化、环保化,从而降低企业的生产成本,提高企业经济效益,推动整个机械制造行业向更加健康的方向发展。
参考文献:
[1]刘武宾.新形势下机械制造与自动化技术分析[J].企业技术开发,2014,08:81+85.
[2]何建立.关于机械制造与自动化应用的研究[J].科技视界,2014,19:99.
[3]张西平.机械制造自动化技术特点与发展趋势[J].河南科技,2013,08:78+82.
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我c,你在这里就想要一篇7000字左右还要英文翻译的论文,你以为人家傻啊,给你写,疯了,自己写去吧,别说7000,,700都别想。自己学那专业的不管怎么说也该能写出点什么,自己都不对自己负责,那么懒,别人凭什么帮你。
机器或装置在无人干预的情况下按规定的程序或指令自动进行操作或控制的过程,其目标是“稳,准,快”。自动化技术广泛用于工业、农业、军事、科学研究、交通运输、商业、医疗、服务和家庭等方面。采用自动化技术不仅可以把人从繁重的体力劳动、部分脑力劳动以及恶劣、危险的工作环境中解放出来,而且能扩展人的器官功能,极大地提高劳动生产率,增强人类认识世界和改造世界的能力。因此,自动化是工业、农业、国防和科学技术现代化的重要条件和显著标志。Machine or device in the absence of intervention procedures or instructions required automatic operation or control of the process and its goal is \u0026quot;steady, accurate and fast.\u0026quot; Automation technology is widely used in industry, agriculture, military, scientific research, transportation, business, health, services, and family and so on. The use of automation technology not only to take people from the heavy manual labor, some mental and poor and dangerous working conditions of liberation, but also to expand people\u0026#39;s organ function, significantly raising labor productivity, enhance human understanding of the world and the ability to change the world . Therefore, the automation industry, agriculture, national defense and modernization of science and technology
1、 [电气工程自动化]恒压供水系统的PLC控制设计 摘要:本文介绍了恒压供水的基本原理以及系统构成的基础,说明了可编程控制器(PLC)在恒压供水系统中所担任的角色。从系统的整体设计方案和实际需求分析开始,紧密的联系实际生活的需要,力求做到使系统运行稳定... 类别:毕业论文 大小:141 KB 日期:2009-02-27 2、 [电气工程自动化]基于DSP2812的永磁同步电机矢量控制系统软件算法设计与研究 2008-12-11 11:59 39,424 评审表.doc2008-12-11 12:00 43,008 文献综述.doc2008-12-11 1... 类别:毕业论文 大小: MB 日期:2008-12-11 3、 [电气工程及其自动化]直流电机PWM调速控制系统的FPGA实现 摘 要文章详细地介绍了直流电机的类型、结构、工作原理、PWM调速原理以及FPGA集成芯片。并对直流电机PWM调速系统方案的组成、硬件电路设计、程序设计及系统仿真分别进行了详细的叙述。拟开发的直流电机P... 类别:毕业论文 大小:812 KB 日期:2008-12-01 4、 [电气工程及其自动化]基于单片机的无刷直流电机控制系统 2007-06-12 22:47 28,672 目录.doc2007-06-12 21:29 41,984 中文翻译.doc2007-06-06 09... 类别:毕业论文 大小:406 KB 日期:2008-11-28 5、 [电气工程及其自动化]低压供配电设备设计选型、安装与试验 目录第一章. 低压供配电系统介绍…………………………………………………3-7第二章. 负荷计算的方法…………………………………………………… 8-12第三章. 低压电器的选型原则……………………………... 类别:毕业论文 大小:449 KB 日期:2008-11-14 6、 [电气工程及其自动化]空气冷却高密度聚乙烯中电树起始过程的观测 中文摘要聚乙烯电气和机械性能优良而广泛应用于绝缘。由于电树枝老化是聚乙烯绝缘破坏的关键因素,研究它具有重要意义。 本文以空气冷却高密度聚乙烯薄膜作为实验对象,主要针对中高频下设备绝缘过早损坏的问题,研... 类别:毕业论文 大小: MB 日期:2008-11-14 7、 [电气工程及其自动化]高压开关微机综合保护装置硬件设计 摘 要煤矿井下6 k V电网防爆开关是矿井供电系统的关键设备,它负责向工作面和掘进面的工机械提供电能。长期以来现场所使用的这种开关载流能力小、保护简单、故障率高,直接影矿井供电的可靠性、安全性和连续... 类别:毕业论文 大小:209 KB 日期:2008-11-08
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