交錯(cuò)并聯(lián)式雙管正激變換器外文資料翻譯

1、 南京理工大學(xué)泰州科技學(xué)院畢業(yè)設(shè)計(jì)(論文)外文資料翻譯(用外文寫)學(xué)院 (系)： 電子電氣工程學(xué)院 專 業(yè)： 電氣工程及其自動(dòng)化 姓 名： 楊 陽(yáng) 學(xué) 號(hào)： 1102570150 外文出處: Journal of Chongqing Normal University,2009,Vol.26(3) 附 件： 1.外文資料翻譯譯文；2.外文原文。 指導(dǎo)教師評(píng)語(yǔ)：所選翻譯資料與課題緊密相關(guān)，數(shù)量和質(zhì)量均符合要求。翻譯流暢，符合漢語(yǔ)閱讀習(xí)慣。整體翻譯質(zhì)量較高。 簽名： 年 月 日注：請(qǐng)將該封面與附件裝訂成冊(cè)。附件1：外文資料翻譯譯文智 能 開(kāi) 關(guān) 電 源 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

2、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(kāi)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(kāi)發(fā)了開(kāi)關(guān)電源。在近半個(gè)世紀(jì)的發(fā)展過(guò)程中，開(kāi)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

3、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(kāi)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(kāi)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(kāi)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(kāi)關(guān)電源有了質(zhì)的飛躍，掀起了電源產(chǎn)品高頻化、小型化、模塊化的浪潮。功率開(kāi)關(guān)管、PWM控制器和高頻變壓器是開(kāi)關(guān)電源必不可少的組成部分。傳統(tǒng)的開(kāi)關(guān)電源一般均采用分立的高頻功率開(kāi)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(kāi)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

4、，使開(kāi)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(kāi)關(guān)集成電路TOP(Three Terminal Off Line)將PWM控制器與功率開(kāi)關(guān)MOSFET合二為一封裝在一起，已成為開(kāi)關(guān)電源IC發(fā)展的主流。采用TOP開(kāi)關(guān)集成電路設(shè)計(jì)開(kāi)關(guān)電源，可使電路簡(jiǎn)化，體積進(jìn)一步縮小，成本也明顯降低。單片開(kāi)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(kāi)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(kāi)關(guān)電源芯片，被譽(yù)為"頂級(jí)開(kāi)關(guān)電源"，具有成本低，電路

5、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(kāi)關(guān)電源的設(shè)計(jì)和新產(chǎn)品的開(kāi)發(fā)工作，也為新型、高效、低成本開(kāi)關(guān)電源的推廣與普及創(chuàng)造了良好條件，可廣泛用于儀器儀表、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(kāi)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

6、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(kāi)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(kāi)關(guān)電源中來(lái). （1）高頻化技術(shù)：隨著開(kāi)關(guān)頻率的提高，開(kāi)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(kāi)關(guān)頻率將上升到MHz。但隨著開(kāi)關(guān)頻率的不斷提高，開(kāi)關(guān)元件和無(wú)源元件損耗的增加、高頻寄生參數(shù)以

7、及高頻EMI等新的問(wèn)題也將隨之產(chǎn)生。 （2）軟開(kāi)關(guān)技術(shù)：為提高變換器的變換效率，各種軟開(kāi)關(guān)技術(shù)應(yīng)用而生，具有代表性的是無(wú)源軟開(kāi)關(guān)技術(shù)和有源軟開(kāi)關(guān)技術(shù)，主要包括零電壓開(kāi)關(guān)/零電流開(kāi)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/ZCT-PWM）技術(shù)等。采用軟開(kāi)關(guān)技術(shù)可以有效的降低開(kāi)關(guān)損耗和開(kāi)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)。

8、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_(kāi)關(guān)電源技術(shù)領(lǐng)域是邊開(kāi)發(fā)相關(guān)電力電子器件，邊開(kāi)發(fā)開(kāi)關(guān)變頻技術(shù)，兩者相互促進(jìn)推動(dòng)著開(kāi)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(kāi)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

9、AC/DC的模塊化，因其自身的特性使得在模塊化的進(jìn)程中，遇到較為復(fù)雜的技術(shù)和工藝制造問(wèn)題。以下分別對(duì)兩類開(kāi)關(guān)電源的結(jié)構(gòu)和特性作以闡述。 開(kāi)關(guān)電源的發(fā)展方向是高頻、高可靠、低耗、低噪聲、抗干擾和模塊化。由于開(kāi)關(guān)電源輕、小、薄的關(guān)鍵技術(shù)是高頻化，因此國(guó)外各大開(kāi)關(guān)電源制造商都致力于同步開(kāi)發(fā)新型高智能化的元器件，特別是改善二次整流器件的損耗，并在功率鐵氧體（Mn?Zn)材料上加大科技創(chuàng)新，以提高在高頻率和較大磁通密度（Bs)下獲得取得了長(zhǎng)足的進(jìn)展，在電路板兩面布置元器件，以確保開(kāi)關(guān)電源的輕、小、薄。開(kāi)關(guān)電源的高頻化就必然對(duì)傳統(tǒng)的PWM開(kāi)關(guān)技術(shù)進(jìn)行創(chuàng)新，實(shí)現(xiàn)ZVS、ZCS的軟開(kāi)關(guān)技術(shù)已成為開(kāi)關(guān)電源的主流

10、技術(shù)，并大幅提高了開(kāi)關(guān)電源的工作效率。對(duì)于高可靠性指標(biāo)，美國(guó)的開(kāi)關(guān)電源生產(chǎn)商通過(guò)降低運(yùn)行電流，降低結(jié)溫等措施以減少器件的應(yīng)力，使得產(chǎn)品的可靠性大大提高。 模塊化是開(kāi)關(guān)電源發(fā)展的總體趨勢(shì)，可以采用模塊化電源組成分布式電源系統(tǒng)，可以設(shè)計(jì)成N1冗余系統(tǒng)，并實(shí)現(xiàn)并聯(lián)方式的容量擴(kuò)展。針對(duì)開(kāi)關(guān)電源運(yùn)行噪聲大這一缺點(diǎn)，若單獨(dú)追求高頻化其噪聲也必將隨著增大，而采用部分諧振轉(zhuǎn)換電路技術(shù)，在理論上即可實(shí)現(xiàn)高頻化又可降低噪聲，但部分諧振轉(zhuǎn)換技術(shù)的實(shí)際應(yīng)用仍存在著技術(shù)問(wèn)題，故仍需在這一領(lǐng)域開(kāi)展大量的工作，以使得該項(xiàng)技術(shù)得以實(shí)用化。 電力電子技術(shù)的不斷創(chuàng)新，使開(kāi)關(guān)電源產(chǎn)業(yè)有著廣闊的發(fā)展前景。要加快我國(guó)開(kāi)關(guān)電源產(chǎn)業(yè)的發(fā)展

11、速度，就必須走技術(shù)創(chuàng)新之路，走出有中國(guó)特色的產(chǎn)學(xué)研聯(lián)合發(fā)展之路，為我國(guó)民經(jīng)濟(jì)的高速發(fā)展做出貢獻(xiàn)。基本原理及元件作用開(kāi)關(guān)電源按控制原理來(lái)分類，大致有以下3種工作方式： 1）脈沖寬度調(diào)制式，簡(jiǎn)稱脈寬調(diào)制(PulseWidth Modulation，縮寫為PWM)式。其主要特點(diǎn)是固定開(kāi)關(guān)頻率，通過(guò)改變脈沖寬度來(lái)調(diào)節(jié)占空比，實(shí)現(xiàn)穩(wěn)壓目的。其核心是脈寬調(diào)制器。開(kāi)關(guān)周期的固定為設(shè)計(jì)濾波電路提供了方便。但是，它的缺點(diǎn)是受功率開(kāi)關(guān)最小導(dǎo)通時(shí)間的限制，對(duì)輸出電壓不能作寬范圍調(diào)節(jié)；此外，輸出端一般要接假負(fù)載(亦稱預(yù)負(fù)載)，以防止空載時(shí)輸出電壓升高。目前，大多數(shù)的集成開(kāi)關(guān)電源采用PWM方式。 2）脈沖頻率調(diào)制方式，

12、簡(jiǎn)稱脈頻調(diào)制(PulseFrequency Modulation，縮寫為PFM)式。其特點(diǎn)是將脈沖寬度固定，通過(guò)改變開(kāi)關(guān)頻率來(lái)調(diào)節(jié)占空比，實(shí)現(xiàn)穩(wěn)壓的目的。其核心是脈頻調(diào)制器。在電路設(shè)計(jì)上要用固定脈寬發(fā)生器來(lái)代替脈寬調(diào)制器中的鋸齒波發(fā)生器，并利用電壓?頻率轉(zhuǎn)換器(例如壓控振蕩器VCO)改變頻率。它的穩(wěn)壓原理是：當(dāng)輸出電壓Uo升高時(shí)，控制器輸出信號(hào)的脈沖寬度不變而周期變長(zhǎng)，使占空比減小，Uo降低。PFM式開(kāi)關(guān)電源的輸出電壓調(diào)節(jié)范圍很寬，輸出端可不接假負(fù)載。PWM方式和PFM方式的調(diào)制波形分別如圖1(a)、(b)所示，tp表示脈沖寬度(即功率開(kāi)關(guān)管的導(dǎo)通時(shí)間tON)，T代表周期。從中可以比較容易的看

13、出兩者的區(qū)別。但它們也有共同之處：（1）均采用時(shí)間比率控制(TRC)的穩(wěn)壓原理，無(wú)論是改變tp還是T，最終調(diào)節(jié)的都是脈沖占空比。盡管采用的方式不同，但控制目標(biāo)一致，可謂殊途同歸。（2）當(dāng)負(fù)載由輕變重，或者輸入電壓從高變時(shí)，分別通過(guò)增加脈寬、升高頻率的方法使輸出電壓保持穩(wěn)定。 3）混合調(diào)制方式，是指脈沖寬度與開(kāi)關(guān)頻率均不固定，彼此都能改變的方式，它屬于PWM和PFM的混合方式。它包含了脈寬調(diào)制器和脈頻調(diào)制器。由于 和T均可單獨(dú)調(diào)節(jié)，因此占空比調(diào)節(jié)范圍最寬，適合制作供實(shí)驗(yàn)室使用的輸出電壓可以寬范圍調(diào)節(jié)的開(kāi)關(guān)電源。以上3種工作方式統(tǒng)稱為“時(shí)間比率控制”(Time Ratio Control，簡(jiǎn)稱TR

14、C)方式。需要指出的是，脈寬調(diào)制器既可作為一片獨(dú)立的集成電路使用(例如UC3842型脈寬調(diào)制器)，亦可被集成在DC/DC變換器中(例如LM2576型開(kāi)關(guān)穩(wěn)壓器集成電路)，還能集成在AC/DC變換器中(例如TOP250型單片開(kāi)關(guān)電源集成電路)。其中，開(kāi)關(guān)穩(wěn)壓器屬于DC/DC電源變換器，開(kāi)關(guān)電源一般為AC/DC電源變換器。 開(kāi)關(guān)電源的典型結(jié)構(gòu)如圖2所示，其工作原理是：市電進(jìn)入電源首先經(jīng)整流和濾波轉(zhuǎn)為高壓直流電，然后通過(guò)開(kāi)關(guān)電路和高頻開(kāi)關(guān)變壓器轉(zhuǎn)為高頻率低壓脈沖，再經(jīng)過(guò)整流和濾波電路，最終輸出低電壓的直流電源。同時(shí)在輸出部分有一個(gè)電路反饋給控制電路，通過(guò)控制PWM占空比以達(dá)到輸出電壓穩(wěn)定。輸入濾波整

15、流濾波高頻變壓器輸出整流濾波輔助電路控制電路保護(hù)動(dòng)作電路檢測(cè)AC輸出直流圖2 開(kāi)關(guān)電源典型結(jié)構(gòu)開(kāi)關(guān)電源由以下4部分構(gòu)成：1）主電路：從交流電網(wǎng)輸入，到直流輸出的主要電路。主要包括輸入濾波器、整流與濾波、逆變、輸出整流與濾波。 （1）輸入濾波器:其作用是將電網(wǎng)存在的雜波過(guò)濾,同時(shí)也阻礙本機(jī)產(chǎn)生的雜波反饋到公共電網(wǎng)。 （2）整流與濾波:將電網(wǎng)交流電源直接整流為較平滑的直流電,以供下一級(jí)變換。 （3）逆變:將整流后的直流電變?yōu)楦哳l交流電,這是高頻開(kāi)關(guān)電源的核心部分,頻率越高,體積、重量與輸出功率之比越小。 （4）輸出整流與濾波:根據(jù)負(fù)載需要,提供穩(wěn)定可靠的直流電源。2）控制電路：一方面從輸出端取樣,

16、經(jīng)與設(shè)定標(biāo)準(zhǔn)進(jìn)行比較,然后去控制逆變器,改變其頻率或脈寬,達(dá)到輸出穩(wěn)定,另一方面,根據(jù)測(cè)試電路提供的數(shù)據(jù),經(jīng)保護(hù)電路鑒別,提供控制電路對(duì)整機(jī)進(jìn)行各種保護(hù)措施。包括輸出端取樣電路、反饋電路和脈寬調(diào)制器。3）檢測(cè)及保護(hù)電路：檢測(cè)電路有過(guò)電流檢測(cè)、過(guò)電壓檢測(cè)、欠電壓檢測(cè)、過(guò)熱檢測(cè)等；保護(hù)電路可分為過(guò)電流保護(hù)、過(guò)電壓保護(hù)、欠電壓保護(hù)、箝位保護(hù)、過(guò)熱保護(hù)、自動(dòng)重啟動(dòng)、軟啟動(dòng)、緩啟動(dòng)等多種類型。4）其他電路：如鋸齒波發(fā)生器、偏置電路、光耦合器等附件2：外文原文Intelligent switch power source With the rapid development of electronic t

17、echnology, 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 equipment are inseparable from reliable power supply for power requirements, they

18、 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 control linear manostat. This traditional manostat technology more mature, a

19、nd 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 transformer and bulk and weight are big filter. In the 1950s, NASA to miniaturiza

20、tion, 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 advantages in electric, control, computer, and many other areas of electro

21、nic 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 equipment, home appliances areas to be widely, switch power technology into the

22、 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. Power switch tube, PWM controller and high-frequency transformer is an indispe

23、nsable 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 small power switch power supply, the design method of a more popularity. S

24、ince 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 provides the broad prospect. Three end off-line pulse width modulation monoli

25、thic 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, can make the circuit simplified, volume further narrowing, cost also is d

26、ecreased obviously. Monolithic 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 supply, etc. American PI (with) company in Power in the mid 1990s first

27、 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 series, the second generation product is the TOPSwitch - debuted in 1997

28、 . 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 switch power supply promotion and popularization created good condition, whi

29、ch 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 can compete with the linear manostat AC/DC power transformation module.

30、 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, no new breakthrough technology progress before major might find it hard

31、 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 digital control IC is the future direction of the development of a swit

32、ch 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,perhaps with the popularity of digital control, and there are some new cont

33、rol 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 - DC converter switch frequency will rise to MHz. But as the switch fre

34、quency 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 order to improve the efficiency of non-linearity of various soft switch,

35、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, zero voltage/zero current pulse width modulation technology (ZVS/ZCS - P

36、WM) 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 efficiency （3）Power factor correction technology (IC simplifies PFC).

37、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 factor, reduce the harmonic pollution of power grid. （4）Modular tec

38、hnology. 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, microprocessor and portable electronic devices work more and more low, this req

39、uires future DC - DC converter can provide low output voltage to adapt microprocessor and power supply requirement of portable electronic devices People in switching power supply technical fields are edge developing related power electronics device, the side of frequency conversion technology, devel

40、opment 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 power supply can be divided into the AC/DC and DC/DC two kinds big, also have AC/AC DC/AC as inv

41、erter 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 process of making modular, meet more complex technology and craft

42、 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 noise, anti-jamming and modular. Because light switch power, small

43、, 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, and power loss of Zn ferrite (Mn) material? By increasing scienti

44、fic 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 supply has made considerable progress, both sides in the circui

45、t board 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 become the mainstream of switch power supply technical, and great

46、ly 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 reliability of products made greatly increased. Modularity is of the ge

47、neral 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 this one defect, if separate the pursuit of high frequency noi

48、se 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 technical problem, so in this area still need to carry out a lot

49、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 China, we must walk speed of technological innovation road,

50、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 function According to the control principle of switch power to classification, we have the following 3 kinds of wor

51、k mode: 1) pulse width adjustment type, abbreviation Modulation PulseWidth pulse width Modulation (PWM) type, abbreviation for. Its main characteristic is fixed switching frequency, pulse width to adjust by changing voltage 390v, realize the purpose. Its core is the pulse width modulator. Switch cyc

52、le 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 loads commonly (also called pre load), in order to prevent

53、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 PulseFrequency Modulation, abbreviation for PFM) type. Its characteristic is will pulse width fixed by changing switch fr

54、equency 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 converter (for example VCO changes frequency VCO). It on voltage

55、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 terminal don't meet dummy loads. PWM way and way of PFM

56、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 common: (1) all use time ratio control (TRC) on voltage stabil

57、ity 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 increasing the pulse width, higher frequency method to ma

58、ke 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 pulsewidth omdulatros 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 voltag