版權(quán)說(shuō)明:本文檔由用戶提供并上傳,收益歸屬內(nèi)容提供方,若內(nèi)容存在侵權(quán),請(qǐng)進(jìn)行舉報(bào)或認(rèn)領(lǐng)
文檔簡(jiǎn)介
1、Intelligent switch power supply英文:With the rapid development of electronic technology, application field of electronic system is more and more extensive, electronic equipment, there are more and more people work with electronic equipment, life is increasingly close relationship. Any electronic equip
2、ment are inseparable from reliable power supply for power requirements, they more and more is also high. Electronic equipment miniaturized and low cost in the power of light and thin, small and efficient for development direction. The traditional transistors series adjustment manostat is continuous
3、control linear manostat. This traditional manostat technology more mature, and there has been a large number of integrated linear manostat module, has the stable performance is good, output ripple voltage small, reliable operation, etc. But usually need are bulky and heavy industrial frequency trans
4、former and bulk and weight are big filter.In the 1950s, NASA to miniaturization, light weight as the goal, for a rocket carrying the switch power development. In almost half a century of development process, switch power because of its small volume, light weight, high efficiency, wide range, voltage
5、 advantages in electric, control, computer, and many other areas of electronic equipment has been widely used. In the 1980s, a computer is made up of all of switch power supply, the first complete computer power generation. Throughout the 1990s, switching power supply in electronics, electrical equi
6、pment, home appliances areas to be widely, switch power technology into the rapid development. In addition, large scale integrated circuit technology, and the rapid development of switch power supply with a qualitative leap, raised high frequency power products of, miniaturization, modular tide.Powe
7、r switch tube, PWM controller and high-frequency transformer is an indispensable part of the switch power supply. The traditional switch power supply is normally made by using high frequency power switch tube division and the pins, such as using PWM integrated controller UC3842 + MOSFET is domestic
8、small power switch power supply, the design method of a more popularity.Since the 1970s, emerged in many function complete integrated control circuit, switch power supply circuit increasingly simplified, working frequency enhances unceasingly, improving efficiency, and for power miniaturization prov
9、ides the broad prospect. Three end off-line pulse width modulation monolithic integrated circuit TOP (Three switch Line) will Terminal Off with power switch MOSFET PWM controller one package together, has become the mainstream of switch power IC development. Adopt TOP switch IC design switch power,
10、can make the circuit simplified, volume further narrowing, cost also is decreased obviouslyMonolithic switching power supply has the monolithic integrated, the minimalist peripheral circuit, best performance index, no work frequency transformer can constitute a significant advantage switching power
11、supply, etc. American PI (with) company in Power in the mid 1990s first launched the new high frequency switching Power supply chip, known as the "top switch Power", with low cost, simple circuit, higher efficiency. The first generation of products launched in 1994 represented TOP100/200 s
12、eries, the second generation product is the TOP Switch - debuted in 1997 . The above products once appeared showed strong vitality and he greatly simplifies thedesign of 150W following switching power supply and the development of new products for the new job, also, high efficiency and low cost swit
13、ch power supply promotion and popularization created good condition, which can be widely used in instrumentation, notebook computers, mobile phones, TV, VCD and DVD, perturbation VCR, mobile phone battery chargers, power amplifier and other fields, and form various miniaturization, density, on price
14、 can compete with the linear manostat AC/DC power transformation module.Switching power supply to integrated direction of future development will be the main trend, power density will more and more big, to process requirements will increasingly high. In semiconductor devices and magnetic materials,
15、no new breakthrough technology progress before major might find it hard to achieve, technology innovation will focus on how to improve the efficiency and focus on reducing weight. Therefore, craft level will be in the position of power supply manufacturing higher in. In addition, the application of
16、digital control IC is the future direction of the development of a switch power. This trust in DSP for speed and anti-interference technology unceasing enhancement. As for advanced control method, now the individual feels haven't seen practicability of the method appears particularly strong,perh
17、aps with the popularity of digital control, and there are some new control theory into switching power supply.(1)The technology: with high frequency switching frequencies increase, switch converter volume also decrease, power density has also been boosted, dynamic response improved. Small power DC -
18、 DC converter switch frequency will rise to MHz. But as the switch frequency unceasing enhancement, switch components and passive components loss increases, high-frequency parasitic parameters and high-frequency EMI and so on the new issues will also be caused.(2)Soft switching technologies: in orde
19、r to improve the efficiency of non-linearity of various soft switch, commutation technical application and hygiene, representative of soft switch technology is passive and active soft switch technology, mainly including zero voltage switch/zero current switch (ZVS/ZCS) resonance, quasi resonant, zer
20、o voltage/zero current pulse width modulation technology (ZVS/ZCS - PWM) and zero voltage transition/zero current transition pulse width modulation (PWM) ZVT/ZCT - technical, etc. By means of soft switch technology can effectively reduce switch loss and switch stress, help converter transformation e
21、fficiency(3)Power factor correction technology (IC simplifies PFC). At present mainly divided into IC simplifies PFC technology passive and active IC simplifies PFC technology using IC simplifies PFC technology two kinds big, IC simplifies PFC technology can improve AC - DC change device input power
22、 factor, reduce the harmonic pollution of power grid.(4)Modular technology. Modular technology can meet the needs of the distributed power system, enhance the system reliability.(5)Low output voltage technology. With the continuous development of semiconductor manufacturing technology, microprocesso
23、r and portable electronic devices work more and more low, this requires future DC - DC converter can provide low output voltage to adapt microprocessor and power supply requirement of portable electronic devicesPeople in switching power supply technical fields are edge developing related power elect
24、ronics device, the side of frequency conversion technology, development of switch between mutual promotion push switch power supply with more than two year growth toward light, digital small, thin, low noise and high reliability, anti-interference direction. Switching powersupply can be divided into
25、 the AC/DC and DC/DC two kinds big, also have AC/AC DC/AC as inverter DC/DC converter is now realize modular, and design technology and production process at home and abroad, are mature and standardization, and has approved by users, but the AC/DC modular, because of its own characteristics in the p
26、rocess of making modular, meet more complex technology and craft manufacture problems. The following two types of switch power supply respectively on the structure and properties of this.Switching power supply is the development direction of high frequency, high reliability, low consumption, low noi
27、se, anti-jamming and modular. Because light switch power, small, thin key techniques are changed, so high overseas each big switch power supply manufacturer are devoted to the development of new high intelligent synchronous rectifier, especially the improvement of secondary devices of the device, an
28、d power loss of Zn ferrite (Mn) material? By increasing scientific and technological innovation, to enhance in high frequency and larger magnetic flux density (Bs) can get high magnetic under the miniaturization of, and capacitor is a key technology. SMT technology application makes switching power
29、supply has made considerable progress, both sides in the circuitboard to ensure that decorate components of switch power supply light, small, thin. The high frequency switching power supply of the traditional PWM must innovate switch technology, to realize the ZCS ZVS, soft switch technology has bec
30、ome the mainstream of switch power supply technical, and greatly improve the efficiency of switch power. For high reliability index, America's switch power producers, reduce by lowering operating current measures such as junction temperature of the device, in order to reduce stress the reliabili
31、ty of products made greatly increased.Modularity is of the general development of switch power supply trend can be modular power component distributed power system, can be designed to N + 1 redundant system, and realize the capacity expansion parallel. According to switch power running large noise t
32、his one defect, if separate the pursuit of high frequency noise will increase its with the partial resonance, and transform circuit technology, high frequency can be realized in theory and can reduce the noise, but part of the practical application of resonant conversion technology still have a tech
33、nical problem, so in this area still need to carry out a lot of work, in order to make the technology to practional utilization.Power electronic technology unceasing innovation, switch power supply industry has broad prospects for development. To speed up the development of switch power industry in
34、China, we must walk speed of technological innovation road, combination with Chinese characteristics in the joint development path, for I the high-speed development of national economy to make the contribution. The basic principle and component functionAccording to the control principle of switch po
35、wer to classification, we have the following 3 kinds of work mode:1) pulse width adjustment type, abbreviation Modulation Pulse Width pulse width Modulation (PWM) type, abbreviation for. Its main characteristic is fixed switching frequency, pulse width to adjust by changing voltage 390v, realize the
36、 purpose. Its core is the pulse width modulator. Switch cycle for designing filter circuit fixed provided convenience. However, its shortcomings is influenced by the power switch conduction time limit minimum of output voltage cannot be wide range regulation; In addition, the output will take dummy
37、loads commonly (also called pre load), in order to prevent the drag elevated when output voltage. At present, most of the integrated switch power adopt PWM way.2) pulse frequency Modulation mode pulse frequency Modulation (, referred to Pulse Frequency Modulation, abbreviation for PFM) type. Its cha
38、racteristic is will pulse width fixed by changing switch frequency to adjust voltage 390v, realize the purpose. Its core is the pulse frequency modulator. Circuit design to use fixed pulse-width generator to replace the pulse width omdulatros and use sawtooth wave generator voltage?Frequency convert
39、er (for example VCO changes frequency VCO). It on voltage stability principle is: when the output voltage Uo rises, the output signal controller pulse width unchanged and cycle longer, make Uo 390v decreases, and reduction. PFM type of switch power supply output voltage range is very wide, output te
40、rminal don't meet dummy loads. PWM way and way of PFM respectively modulating waveform is shown in figure 1 (a), (b) shows, tp says pulse width (namely power switch tube conduction time tON), T represent cycle. It can be easy to see the difference between the two. But they have something in comm
41、on: (1) all use time ratio control (TRC) on voltage stability principle, whether change tp, finally adjustment or T is pulse 390v. Although adopted in different ways, but control goals, is all rivers run into the sea. (2) when load by light weight, or input voltage respectively, from high changed by
42、 increasing the pulse width, higher frequency method to make the output voltage remained stable.3) mix modulation mode, it is to point to the pulse width and switching frequency is not fixed, each other can change, it belongs to the way the PWM and PFM blend mode. It contains a pulsewidthomdulatros
43、and pulse frequency modulator. Because and T all can adjust alone, so occupies emptiescompared to adjust the most wide range, suitable for making the output voltage for laboratories that use a wide range of can adjust switching power supply. Above 3 work collectively referred to as "Time Ratio
44、Control" (as a Control, from TRC) way. As noted, pulse width omdulatros either as a independent IC use (for example UC3842 type pulse width omdulatros), can also be integrated in DC/DC converter (for example LM2576 type switching voltage regulators integrated circuit), still can integration in
45、AC/DC converter (for example TOP250 type monolithic integrated circuit switching power supply. Among them, the switching voltage regulators belong to DC/DC power converter, switching power supply general for AC/DC power converter.The typical structure of switch power as figure1shows, its working pri
46、nciple is: the first utility into power rectifier and filtering into high voltage dc and then through the switch circuit and high-frequency switch to high frequency low pressure pulse transformer, and then after rectification and filter circuits, finally output low voltage dc power. Meanwhile in the
47、 output parts have a circuit feedback to control circuit, through the control PWM occupies emptiescompared to achieve output voltage stability.Figure 1 typical structure of switch power supplySwitching power supply by these four components:1) the main circuit: exchange network input, from the main c
48、ircuit to dc output. Mainly includes input filter, rectifier and filtering, inverter, and output rectifier and filtering.(1) input filter: its effect is the power grid existing clutter filtering, also hinder the machine produces clutter feedback to public power grid.(2) rectifier and filter: the pow
49、er grid ac power directly for a smooth dc rectifier, for the next level transformation.(3) inverter: will the dc after rectifying a high-frequency ac, this is the core of high frequency switching power supply, the higher the frequency, the volume, weight and the ratio of power output and smaller.(4)
50、 Out put rectifier and filter: according to load needs, providing stable and reliable dc power supply. 2) control circuit: on the one hand, from the output by sampling with set standards to compare, and then to control inverter, changing its frequency or pulse width, achieve output stability, on the
51、 other hand, according to data provided by the test circuit, the protection circuit differential, provide control circuit to the machine to various protection measures. Including the output feedback circuit and sampling circuit, pulse width modulator. 3) the detection and protection circuit: detecti
52、on circuit had current detection, over-voltage detection, owe voltage detection, overheat detection, etc.; Protection circuit can be divided over current protection, over-voltage protection, owe voltage protection, the ground-clamp protection, overheating protection, automatic restart, soft start, s
53、low startup, etc. Various types. 4) Other circuit: if the sawtooth wave generator, offset circuit, optical coupler, etc.智能開關(guān)電源中文:隨著電子技術(shù)的高速發(fā)展,電子系統(tǒng)的應(yīng)用領(lǐng)域越來(lái)越廣泛,電子設(shè)備的種類也越來(lái)越多,電子設(shè)備與人們的工作、生活的關(guān)系日益密切。任何電子設(shè)備都離不開可靠的電源,它們對(duì)電源的要求也越來(lái)越高。電子設(shè)備的小型化和低成本化使電源以輕、薄、小和高效率為發(fā)展方向。傳統(tǒng)的晶體管串聯(lián)調(diào)整穩(wěn)壓電源是連續(xù)控制的線性穩(wěn)壓電源。這種傳統(tǒng)穩(wěn)壓電源技術(shù)比較成熟,并且已有大量
54、集成化的線性穩(wěn)壓電源模塊,具有穩(wěn)定性能好、輸出波紋電壓小、使用可靠等優(yōu)點(diǎn)。但通常都需要體積大且笨重的工頻變壓器與體積和重量都很大的濾波器。二十世紀(jì)五十年代,美國(guó)宇航局以小型化、重量輕為目標(biāo),為搭載火箭開發(fā)了開關(guān)電源。在近半個(gè)世紀(jì)的發(fā)展過(guò)程中,開關(guān)電源因具有重量輕、體積小、效率高、穩(wěn)壓范圍寬等優(yōu)點(diǎn),在電子電氣、控制、計(jì)算機(jī)等許多領(lǐng)域的電子設(shè)備中得到了廣泛的使用。二十世紀(jì)八十年代,計(jì)算機(jī)全面實(shí)現(xiàn)了開關(guān)電源化,率先完成計(jì)算機(jī)的電源換代。二十世紀(jì)九十年代,開關(guān)電源在電子、電器設(shè)備、家電領(lǐng)域得到了廣泛的應(yīng)用,開關(guān)電源技術(shù)進(jìn)入快速發(fā)展期。此外,大規(guī)模集成電路技術(shù)的迅速發(fā)展,又使開關(guān)電源有了質(zhì)的飛躍,掀起了
55、電源產(chǎn)品高頻化、小型化、模塊化的浪潮。功率開關(guān)管、PWM控制器和高頻變壓器是開關(guān)電源必不可少的組成部分。傳統(tǒng)的開關(guān)電源一般均采用分立的高頻功率開關(guān)管和多引腳的PWM集成控制器,例如采用UC3842+MOSFET是國(guó)內(nèi)小功率開關(guān)電源中較為普及的設(shè)計(jì)方法。七十年代以來(lái),涌現(xiàn)出許多功能完備的集成控制電路,使開關(guān)電源電路日益簡(jiǎn)化,工作頻率不斷提高,效率提高,并為電源小型化提供了廣闊的前景。三端離線式脈寬調(diào)制單片開關(guān)集成電路TOP(Three Terminal Off Line)將PWM控制器與功率開關(guān)MOSFET合二為一封裝在一起,已成為開關(guān)電源IC發(fā)展的主流。采用TOP開關(guān)集成電路設(shè)計(jì)開關(guān)電源,可使
56、電路簡(jiǎn)化,體積進(jìn)一步縮小,成本也明顯降低。單片開關(guān)電源具有單片集成化、最簡(jiǎn)外圍電路、最佳性能指標(biāo)、能構(gòu)成無(wú)工頻變壓器開關(guān)電源等顯著優(yōu)點(diǎn)。美國(guó)PI(Power Integration)公司于上世紀(jì)九十年代中期率先推出的新型高頻開關(guān)電源芯片,被譽(yù)為"頂級(jí)開關(guān)電源",具有成本低,電路簡(jiǎn)單,效率高等優(yōu)點(diǎn)。其第一代產(chǎn)品以1994年推出的TOP100/200系列為代表,第二代產(chǎn)品則是1997年問(wèn)世的TOPSwitch-。上述產(chǎn)品一經(jīng)問(wèn)世便顯示出強(qiáng)大的生命力,他極大地簡(jiǎn)化了150W以下開關(guān)電源的設(shè)計(jì)和新產(chǎn)品的開發(fā)工作,也為新型、高效、低成本開關(guān)電源的推廣與普及創(chuàng)造了良好條件,可廣泛用于儀
57、器儀表、筆記本電腦、移動(dòng)電話、電視機(jī)、VCD和DVD、攝錄像機(jī)、手機(jī)電池充電器、功率放大器等領(lǐng)域,并構(gòu)成各種小型化、高密度、在價(jià)格上能與線性穩(wěn)壓電源相競(jìng)爭(zhēng)的AC/DC電源變換模塊。開關(guān)電源向集成化方向發(fā)展將是未來(lái)的主要趨勢(shì),功率密度將越來(lái)越大,對(duì)工藝的要求也會(huì)越來(lái)越高.在半導(dǎo)體器件和磁性材料沒(méi)有新的突破之前,重大的技術(shù)進(jìn)展可能很難實(shí)現(xiàn),技術(shù)創(chuàng)新的重點(diǎn)將集中在如何提高效率和減小重量.因此,工藝水平將會(huì)在電源制造中占的地位越來(lái)越高.另外,數(shù)字控制集成電路的應(yīng)用也是將來(lái)開關(guān)電源發(fā)展的一個(gè)方向.這信賴于DSP運(yùn)行速度和抗干擾技術(shù)的不斷提高.至于先進(jìn)的控制方法,目前個(gè)人覺(jué)得還沒(méi)有看到實(shí)用性特別強(qiáng)的方法出
58、現(xiàn),也許隨著數(shù)字控制的普及,會(huì)有一些新的控制理論運(yùn)用到開關(guān)電源中來(lái).(1)高頻化技術(shù):隨著開關(guān)頻率的提高,開關(guān)變換器的體積也隨之減少,功率密度也得到大幅提升,動(dòng)態(tài)響應(yīng)得到改善。小功率DC-DC變換器的開關(guān)頻率將上升到MHz。但隨著開關(guān)頻率的不斷提高,開關(guān)元件和無(wú)源元件損耗的增加、高頻寄生參數(shù)以及高頻EMI等新的問(wèn)題也將隨之產(chǎn)生。(2)軟開關(guān)技術(shù):為提高變換器的變換效率,各種軟開關(guān)技術(shù)應(yīng)用而生,具有代表性的是無(wú)源軟開關(guān)技術(shù)和有源軟開關(guān)技術(shù),主要包括零電壓開關(guān)/零電流開關(guān)(ZVS/ZCS)諧振、準(zhǔn)諧振、零電壓/零電流脈寬調(diào)制技術(shù)(ZVS/ZCS-PWM)以及零電壓過(guò)渡/零電流過(guò)渡脈寬調(diào)制(ZVT/
59、ZCT-PWM)技術(shù)等。采用軟開關(guān)技術(shù)可以有效的降低開關(guān)損耗和開關(guān)應(yīng)力,有助于變換器變換效率的提高。(3)功率因數(shù)校正技術(shù)(PFC)。目前PFC技術(shù)主要分為有源PFC技術(shù)和無(wú)源PFC技術(shù)兩大類,采用PFC技術(shù)可以提高AC-DC變化器輸入端功率因數(shù),減少對(duì)電網(wǎng)的諧波污染。(4)模塊化技術(shù)。采用模塊化技術(shù)可以滿足分布式電源系統(tǒng)的需要,提高系統(tǒng)的可靠性。(5)低輸出電壓技術(shù)。隨著半導(dǎo)體制造技術(shù)的不斷發(fā)展,微處理器和便攜式電子設(shè)備的工作越來(lái)越低,這就要求未來(lái)的DC-DC變換器能夠提供低輸出電壓以適應(yīng)微處理器和便攜式電子設(shè)備的供電要求。人們?cè)陂_關(guān)電源技術(shù)領(lǐng)域是邊開發(fā)相關(guān)電力電子器件,邊開發(fā)開關(guān)變頻技術(shù),兩者相互促進(jìn)推動(dòng)著開關(guān)電源每年以超過(guò)兩位數(shù)字的增長(zhǎng)率向著輕、小、薄、低噪聲、高可靠、抗干擾的方向發(fā)展。開關(guān)電源可分為AC/DC和DC/DC兩大類,也有AC/AC DC/AC 如逆變器 DC/DC變換器現(xiàn)已實(shí)現(xiàn)模塊化,且設(shè)計(jì)技術(shù)及生產(chǎn)工藝在國(guó)內(nèi)外均已成熟和標(biāo)準(zhǔn)化,并已得到用戶的認(rèn)可,但AC/DC的模塊化,因其自身的特性使得在模塊化的進(jìn)程中,
溫馨提示
- 1. 本站所有資源如無(wú)特殊說(shuō)明,都需要本地電腦安裝OFFICE2007和PDF閱讀器。圖紙軟件為CAD,CAXA,PROE,UG,SolidWorks等.壓縮文件請(qǐng)下載最新的WinRAR軟件解壓。
- 2. 本站的文檔不包含任何第三方提供的附件圖紙等,如果需要附件,請(qǐng)聯(lián)系上傳者。文件的所有權(quán)益歸上傳用戶所有。
- 3. 本站RAR壓縮包中若帶圖紙,網(wǎng)頁(yè)內(nèi)容里面會(huì)有圖紙預(yù)覽,若沒(méi)有圖紙預(yù)覽就沒(méi)有圖紙。
- 4. 未經(jīng)權(quán)益所有人同意不得將文件中的內(nèi)容挪作商業(yè)或盈利用途。
- 5. 人人文庫(kù)網(wǎng)僅提供信息存儲(chǔ)空間,僅對(duì)用戶上傳內(nèi)容的表現(xiàn)方式做保護(hù)處理,對(duì)用戶上傳分享的文檔內(nèi)容本身不做任何修改或編輯,并不能對(duì)任何下載內(nèi)容負(fù)責(zé)。
- 6. 下載文件中如有侵權(quán)或不適當(dāng)內(nèi)容,請(qǐng)與我們聯(lián)系,我們立即糾正。
- 7. 本站不保證下載資源的準(zhǔn)確性、安全性和完整性, 同時(shí)也不承擔(dān)用戶因使用這些下載資源對(duì)自己和他人造成任何形式的傷害或損失。
最新文檔
- 2024-2030年撰寫:中國(guó)棉籽榨油機(jī)行業(yè)發(fā)展趨勢(shì)及競(jìng)爭(zhēng)調(diào)研分析報(bào)告
- 2024-2030年奧澤格瑞鈉公司技術(shù)改造及擴(kuò)產(chǎn)項(xiàng)目可行性研究報(bào)告
- 2024-2030年基因工程霍亂疫苗藥品公司技術(shù)改造及擴(kuò)產(chǎn)項(xiàng)目可行性研究報(bào)告
- 2024-2030年商用飛機(jī)視頻監(jiān)控系統(tǒng)行業(yè)市場(chǎng)現(xiàn)狀供需分析及重點(diǎn)企業(yè)投資評(píng)估規(guī)劃分析研究報(bào)告
- 2024-2030年全球及中國(guó)高碳鉻鐵行業(yè)需求現(xiàn)狀及前景趨勢(shì)預(yù)測(cè)報(bào)告
- 2024-2030年全球及中國(guó)跳傘服務(wù)行業(yè)營(yíng)銷動(dòng)態(tài)及投資盈利預(yù)測(cè)報(bào)告
- 2024年度圖書館讀者活動(dòng)圖書采購(gòu)合同范本3篇
- 2024-2030年全球及中國(guó)液體膠囊過(guò)濾器行業(yè)銷售渠道及需求前景預(yù)測(cè)報(bào)告
- 2024-2030年全球及中國(guó)工業(yè)干洗機(jī)器行業(yè)需求趨勢(shì)及投資盈利預(yù)測(cè)報(bào)告
- 2024-2030年全球及中國(guó)噴灌設(shè)備行業(yè)產(chǎn)銷狀況及未來(lái)需求趨勢(shì)預(yù)測(cè)報(bào)告
- “東數(shù)西算”全面解讀學(xué)習(xí)課件
- 經(jīng)濟(jì)博弈論(謝織予)課后答案及補(bǔ)充習(xí)題答案
- 導(dǎo)游考試指南:一個(gè)月過(guò)北京導(dǎo)游考試
- 基于分形結(jié)構(gòu)的多頻與寬帶天線技術(shù)研究
- 人間生活-中國(guó)部分+課件高中美術(shù)湘美版(2019)美術(shù)鑒賞1
- YY/T 1771-2021彎曲-自由恢復(fù)法測(cè)試鎳鈦形狀記憶合金相變溫度
- JJF 1874-2020(自動(dòng))核酸提取儀校準(zhǔn)規(guī)范
- GB/T 7378-2012表面活性劑堿度的測(cè)定滴定法
- GB/T 37762-2019同步調(diào)相機(jī)組保護(hù)裝置通用技術(shù)條件
- GB/T 36961-2018超高強(qiáng)鋼熱沖壓工藝通用技術(shù)
- GB/T 33609-2017軟質(zhì)泡沫聚合材料滯后損失試驗(yàn)方法
評(píng)論
0/150
提交評(píng)論