電力電子技術外文翻譯文獻（文檔含中英文對照即英文原文和中文翻譯）譯文:基于單片機的開關電源1用途開關電源產品在工業自動化控制、軍工設備、科研設備、LED照明、工控設備、通訊設備、電力設備、儀器儀表、醫療設備、半導體制冷制熱、空氣凈化器，電子冰箱，液晶顯示器，LED燈具，通訊設備，視聽產品，安防，電腦機箱，數碼產品和儀器類等領域中得到廣泛應用。2簡介隨著電力電子技術的高速發展，電力電子設備與人們的工作、生活的關系日益密切，而電子設備都離不開可靠的電源，進入80年代計算機電源全面實現了開關電源化，率先完成計算機的電源換代，進入90年代開關電源相繼進入各種電子、電器設備領域，程控交換機、通訊、電子檢測設備電源、控制設備電源等都已廣泛地使用了開關電源，更促進了開關電源技術的迅速發展。開關電源是利用現代電力電子技術，控制開關晶體管開通和關斷的時間比率，維持穩定輸出電壓的一種電源，開關電源一般由脈沖寬度調制（PWM）控制IC和開關器件（MOSFET、BJT等）構成。開關電源和線性電源相比，二者的成本都隨著輸出功率的增加而增長，但二者增長速率各異。線性電源成本在某一輸出功率點上，反而高于開關電源。隨著電力電子技術的發展和創新，使得開關電源技術在不斷地創新，這一成本反轉點日益向低輸出電力端移動，這為開關電源提供了廣泛的發展空間。開關電源高頻化是其發展的方向，高頻化使開關電源小型化，并使開關電源進入更廣泛的應用領域，特別是在高新技術領域的應用，推動了高新技術產品的小型化、輕便化。另外開關電源的發展與應用在節約能源、節約資源及保護環境方面都具有重要的意義。3分類現代開關電源有兩種：一種是直流開關電源；另一種是交流開關電源。這里主要介紹的只是直流開關電源，其功能是將電能質量較差的原生態電源（粗電），如市電電源或蓄電池電源，轉換成滿足設備要求的質量較高的直流電壓（精電）。直流開關電源的核心是DC/DC轉換器。因此直流開關電源的分類是依賴DC/DC轉換器分類的。也就是說，直流開關電源的分類與DC/DC轉換器的分類是基本相同的，DC/DC轉換器的分類基本上就是直流開關電源的分類。直流DC/DC轉換器按輸入與輸出之間是否有電氣隔離可以分為兩類：一類是有隔離的稱為隔離式DC/DC轉換器;另一類是沒有隔離的稱為非隔離式DC/DC轉換器。隔離式DC/DC轉換器也可以按有源功率器件的個數來分類。單管的DC/DC轉換器有正激式（Forward）和反激式（Feedback）兩種。雙管DC/DC轉換器有雙管正激式（DoubleTransistorForwardConverter），雙管反激式（DoubleTransistorFeedbackConverter）、推挽式（Push-PullConverter）和半橋式（Half-BridgeConverter）四種。四管DC/DC轉換器就是全橋DC/DC轉換器（Full-BridgeConverter）。非隔離式DC/DC轉換器，按有源功率器件的個數，可以分為單管、雙管和四管三類。單管DC/DC轉換器共有六種，即降壓式（Buck）DC/DC轉換器，升壓式（Boost）DC/DC轉換器、升壓降壓式（BuckBoost）DC/DC轉換器、CukDC/DC轉換器、ZetaDC/DC轉換器和SEPICDC/DC轉換器。在這六種單管DC/DC轉換器中，Buck和Boost式DC/DC轉換器是基本的，Buck-Boost、Cuk、Zeta、SEPIC式DC/DC轉換器是從中派生出來的。雙管DC/DC轉換器有雙管串接的升壓式（Buck-Boost）DC/DC轉換器。四管DC/DC轉換器常用的是全橋DC/DC轉換器（Full-BridgeConverter）。隔離式DC/DC轉換器在實現輸出與輸入電氣隔離時，通常采用變壓器來實現，由于變壓器具有變壓的功能，所以有利于擴大轉換器的輸出應用范圍，也便于實現不同電壓的多路輸出，或相同電壓的多種輸出。在功率開關管的電壓和電流定額相同時，轉換器的輸出功率通常與所用開關管的數量成正比。所以開關管數越多，DC/DC轉換器的輸出功率越大，四管式比兩管式輸出功率大一倍，單管式輸出功率只有四管式的1/4。非隔離式轉換器與隔離式轉換器的組合，可以得到單個轉換器所不具各的一些特性。按能量的傳輸來分，DC/DC轉換器有單向傳輸和雙向傳輸兩種。具有雙向傳輸功能的DC/DC轉換器，既可以從電源側向負載側傳輸功率，也可以從負載側向電源側傳輸功率。DC/DC轉換器也可以分為自激式和他控式。借助轉換器本身的正反饋信號實現開關管自持周期性開關的轉換器，叫做自激式轉換器，如洛耶爾（Royer）轉換器就是一種典型的推挽自激式轉換器。他控式DC/DC轉換器中的開關器件控制信號，是由外部專門的控制電路產生的。4開關電源的分類人們在開關電源技術領域是邊開發相關電力電子器件，邊開發開關變頻技術，兩者相互促進推動著開關電源每年以超過兩位數字的增長率向著輕、小、薄、低噪聲、高可靠、抗干擾的方向發展。開關電源可分為AC/DC和DC/DC兩大類，也有AC/ACDC/AC如逆變器DC/DC變換器現已實現模塊化，且設計技術及生產工藝在國內外均已成熟和標準化，并已得到用戶的認可，但AC/DC的模塊化，因其自身的特性使得在模塊化的進程中，遇到較為復雜的技術和工藝制造問題。以下分別對兩類開關電源的結構和特性作以闡述。自激式：是無須外加信號源能自行振蕩，自激式完全可以把它看作是一個變壓器反饋式振蕩電路。它激式：則完全依賴于外部維持振蕩，在實際應用中它激式應用比較廣泛。根據激勵信號結構分類；可分為脈沖調寬和脈沖調幅兩種，脈沖調寬是控制信號的寬度，也就是頻率，脈沖調幅控制信號的幅度，兩者的作用相同都是使振蕩頻率維持在某一范圍內，達到穩定電壓的效果。變壓器的繞組一般可以分成三種類型，一組是參與振蕩的初級繞組，一組是維持振蕩的反饋繞組，還有一組是負載繞組。比如在家用電器中使用的上海正藝科技生產的開關電源，將220V的交流電經過橋式整流，變換成300V左右的直流電，濾波后進入變壓器后加到開關管的集電極進行高頻振蕩，反饋繞組反饋到基極維持電路振蕩，負載繞組感應的電信號，經整流、濾波、穩壓得到的直流電壓給負載提供電能。負載繞組在提供電能的同時，也肩負起穩定電壓的能力，其原理是在電壓輸出電路接一個電壓取樣裝置，監測輸出電壓的變化情況,及時反饋給振蕩電路調整振蕩頻率，從而達到穩定電壓的目的，為了避免電路的干擾，反饋回振蕩電路的電壓會用光電耦合器隔離。5技術發展動向開關電源高頻化是其發展的方向，高頻化使開關電源小型化，并使開關電源進入更廣泛的應用領域，特別是在高新技術領域的應用，推動了開關電源的發展前進,每年以超過兩位數字的增長率向著輕、小、薄、低噪聲、高可靠、抗干擾的方向發展。開關電源可分為AC/DC和DC/DC兩大類，DC/DC變換器現已實現模塊化，且設計技術及生產工藝在國內外均已成熟和標準化，并已得到用戶的認可，但AC/DC的模塊化，因其自身的特性使得在模塊化的進程中，遇到較為復雜的技術和工藝制造問題。另外，開關電源的發展與應用在節約能源、節約資源及保護環境方面都具有重要的意義。開關電源中應用的電力電子器件主要為二極管、IGBT和MOSFET。SCR在開關電源輸入整流電路及軟啟動電路中有少量應用，GTR驅動困難，開關頻率低，逐漸被IGBT和MOSFET取代。開關電源的發展方向是高頻、高可靠、低耗、低噪聲、抗干擾和模塊化。由于開關電源輕、小、薄的關鍵技術是高頻化，因此國外各大開關電源制造商都致力于同步開發新型高智能化的元器件，特別是改善二次整流器件的損耗，并在功率鐵氧體材料上加大科技創新，以提高在高頻率和較大磁通密度（Bs）下獲得高的磁性能，而電容器的小型化也是一項關鍵技術oSMT技術的應用使得開關電源取得了長足的進展，在電路板兩面布置元器件，以確保開關電源的輕、小、薄。開關電源的高頻化就必然對傳統的PWM開關技術進行創新，實現ZVS、ZCS的軟開關技術已成為開關電源的主流技術，并大幅提高了開關電源的工作效率。對于高可靠性指標，美國的開關電源生產商通過降低運行電流，降低結溫等措施以減少器件的應力，使得產品的可靠性大大提高。模塊化是開關電源發展的總體趨勢，可以采用模塊化電源組成分布式電源系統，可以設計成N+1冗余電源系統，并實現并聯方式的容量擴展。針對開關電源運行噪聲大這一缺點，若單獨追求高頻化其噪聲也必將隨著增大，而采用部分諧振轉換電路技術，在理論上即可實現高頻化又可降低噪聲，但部分諧振轉換技術的實際應用仍存在著技術問題，故仍需在這一領域開展大量的工作，以使得該項技術得以實用化。電力電子技術的不斷創新，使開關電源產業有著廣闊的發展前景。要加快我國開關電源產業的發展速度，就必須走技術創新之路，走出有中國特色的產學研聯合發展之路，為我國國民經濟的高速發展做出貢獻。1955年美國羅耶（Roger）發明的自激振蕩推挽晶體管單變壓器直流變換器，是實現高頻轉換控制電路的開端，1957年美國查賽JenSen）發明了自激式推挽雙變壓器，1964年美國科學家們提出取消工頻變壓器的串聯開關電源的設想，這對電源向體積和重量的下降獲得了一條根本的途徑。到了1969年由于大功率硅晶體管的耐壓提高，二極管反向恢復時間的縮短等元器件改善，終于做成了25千赫的開關電源。目前，開關電源以小型、輕量和高效率的特點被廣泛應用于以電子計算機為主導的各種終端設備、通信設備等幾乎所有的電子設備，是當今電子信息產業飛速發展不可缺少的一種電源方式。目前市場上出售的開關電源中采用雙極性晶體管制成的100kHz、用MOS—FET制成的500kHz電源，雖已實用化，但其頻率有待進一步提高。要提高開關頻率，就要減少開關損耗，而要減少開關損耗，就需要有高速開關元器件。然而，開關速度提高后，會受電路中分布電感和電容或二極管中存儲電荷的影響而產生浪涌或噪聲。這樣，不僅會影響周圍電子設備，還會大大降低電源本身的可靠性。其中，為防止隨開關啟-閉所發生的電壓浪涌，可采用R-C或L-C緩沖器，而對由二極管存儲電荷所致的電流浪涌可采用非晶態等磁芯制成的磁緩沖器。不過，對1MHz以上的高頻，要采用諧振電路，以使開關上的電壓或通過開關的電流呈正弦波，這樣既可減少開關損耗，同時也可控制浪涌的發生。這種開關方式稱為諧振式開關。目前對這種開關電源的研究很活躍，因為采用這種方式不需要大幅度提高開關速度就可以在理論上把開關損耗降到零，而且噪聲也小，可望成為開關電源高頻化的一種主要方式。當前，世界上許多國家都在致力于數兆Hz的變換器的實用化研究。6原理簡介開關電源的工作過程相當容易理解，在線性電源中，讓功率晶體管工作在線性模式，與線性電源不同的是,PWM開關電源是讓功率晶體管工作在導通和關斷的狀態,在這兩種狀態中，加在功率晶體管上的伏-安乘積是很小的（在導通時，電壓低，電流大；關斷時，電壓高，電流小）/功率器件上的伏安乘積就是功率半導體器件上所產生的損耗。與線性電源相比，PWM開關電源更為有效的工作過程是通過“斬波”，即把輸入的直流電壓斬成幅值等于輸入電壓幅值的脈沖電壓來實現的。脈沖的占空比由開關電源的控制器來調節。一旦輸入電壓被斬成交流方波，其幅值就可以通過變壓器來升高或降低。通過增加變壓器的二次繞組數就可以增加輸出的電壓組數。最后這些交流波形經過整流濾波后就得到直流輸出電壓。控制器的主要目的是保持輸出電壓穩定，其工作過程與線性形式的控制器很類似。也就是說控制器的功能塊、電壓參考和誤差放大器，可以設計成與線性調節器相同。他們的不同之處在于，誤差放大器的輸出（誤差電壓）在驅動功率管之前要經過一個電壓/脈沖寬度轉換單元。開關電源有兩種主要的工作方式：正激式變換和升壓式變換。盡管它們各部分的布置差別很小，但是工作過程相差很大，在特定的應用場合下各有優點。7電路原理所謂開關電源，顧名思義，就是這里有一扇門，一開門電源就通過，一關門電源就停止通過，那么什么是門呢，開關電源里有的采用可控硅，有的采用開關管，這兩個元器件性能差不多，都是靠基極、（開關管）控制極（可控硅）上加上脈沖信號來完成導通和截止的，脈沖信號正半周到來，控制極上電壓升高，開關管或可控硅就導通，由220V整流、濾波后輸出的300V電壓就導通，通過開關變壓器傳到次級，再通過變壓比將電壓升高或降低，供各個電路工作。振蕩脈沖負半周到來，電源調整管的基極、或可控硅的控制極電壓低于原來的設置電壓，電源調整管截止，300V電源被關斷，開關變壓器次級沒電壓，這時各電路所需的工作電壓，就靠次級本路整流后的濾波電容放電來維持。待到下一個脈沖的周期正半周信號到來時，重復上一個過程。這個開關變壓器就叫高頻變壓器，因為他的工作頻率高于50HZ低頻。那么推動開關管或可控硅的脈沖如何獲得呢，這就需要有個振蕩電路產生，我們知道，晶體三極管有個特性，就是基極對發射極電壓是0.65-0.7V是放大狀態，0.7V以上就是飽和導通狀態，-0.1V--0.3V就工作在振蕩狀態，那么其工作點調好后，就靠較深的負反饋來產生負壓，使振蕩管起振，振蕩管的頻率由基極上的電容充放電的時間長短來決定，振蕩頻率高輸出脈沖幅度就大，反之就小，這就決定了電源調整管的輸出電壓的大小。那么變壓器次級輸出的工作電壓如何穩壓呢，一般是在開關變壓器上，單繞一組線圈，在其上端獲得的電壓經過整流濾波后，作為基準電壓，然后通過光電耦合器，將這個基準電壓返回振蕩管的基極，來調整震蕩頻率的高低，如果變壓器次級電壓升高，本取樣線圈輸出的電壓也升高，通過光電耦合器獲得的正反饋電壓也升高，這個電壓加到振蕩管基極上，就使振蕩頻率降低，起到了穩定次級輸出電壓的穩定，太細的工作情況就不必細講了，也沒必要了解的那么細的，這樣大功率的電壓由開關變壓器傳遞，并與后級隔開，返回的取樣電壓由光耦傳遞也與后級隔開，所以前級的市電電壓，是與后級分離的，這就叫冷板，是安全的，變壓器前的電源是獨立的，這就叫開關電源。8DC/DC變換DC/DC變換是將固定的直流電壓變換成可變的直流電壓，也稱為直流斬波。斬波器的工作方式有兩種，一是脈寬調制方式Ts不變，改變ton（通用），二是頻率調制方式，ton不變，改變Ts（易產生干擾）。其具體的電路由以下幾類：Buck電路一一降壓斬波器，其輸出平均電壓U0小于輸入電壓Ui,極性相同。Boost電路一一升壓斬波器，其輸出平均電壓開關電源及電路圖U0大于輸入電壓Ui，極性相同。Buck-Boost電路一一降壓或升壓斬波器，其輸出平均電壓U0大于或小于輸入電壓Ui，極性相反，電感傳輸。Cuk電路一一降壓或升壓斬波器，其輸出平均電 壓U0大于或小于輸入電壓Ui,極性相反，電容傳輸。上述為非隔離型電路，隔離型電路有正激電路、反激電路、半橋電路、全橋電路、推挽電路。 當今軟開關技術使得DC/DC發生了質的飛躍，美國VICOR公司設計制造的多種ECI軟開關DC/DC變換器，其最大輸出功率有300W、600W、800W等,相應的功率密度為（6.2、10、17）W/cm3,效率為（80?90）%。日本NemicLambda公司最新推出的一種采用軟開關技術的高頻開關電源模塊RM系列，其開關頻率為（200?300）kHz,功率密度已達到27W/cm3，采用同步整流器（MOSFET代替肖特基二極管），使整個電路效率提高到90%。9AC/DC變換AC/DC變換是將交流變換為直流，其功率流向可以是雙向的，功率流由電源流向負載的稱為“整流”功率流由負載返回電源的稱為“有源逆變”AC/DC變換器輸入為50/60Hz的交流電，因必須經整流、濾波，因此體積相對較大的濾波電容器是必不可少的，同時因遇到安全標準（如UL、CCEE等）及EMC指令的限制（如IEC、、FCC、CSA）,交流輸入側必須加EMC濾波及使用符合安全標準的元件，這樣就限制AC/DC電源體積的小型化，另外，由于內部的高頻、高壓、大電流開關動作，使得解決EMC電磁兼容問題難度加大，也就對內部高密度安裝電路設計提出了很高的要求，由于同樣的原因，高電壓、大電流開關使得電源工作損耗增大，限制了AC/DC變換器模塊化的進程，因此必須采用電源系統優化設計方法才能使其工作效率達到一定的滿意程度。AC/DC變換按電路的接線方式可分為，半波電路、全波電路。按電源相數可分為,單相、三相、多相。按電路工作象限又可分為一象限、二象限、三象限、四象限。開關電源在輸入抗干擾性能上，由于其自身電路結構的特點（多級串聯），一般的輸入干擾如浪涌電壓很難通過，在輸出電壓穩定度這一技術指標上與線性電源相比具有較大的優勢，其輸出電壓穩定度可達（0.5~1）%。開關電源模塊作為一種電力電子集成器件，要注意選擇。原文：ThedesignBasedonsinglechipswitchingpowersupplyUsesTheswitchingpowersupplyproductsarewidelyusedinindustrialautomationandcontrol,militaryequipment,scientificequipment,LEDlighting,industrialequipment,communicationsequipment,electricalequipment,instrumentation,medicalequipment,semiconductorcoolingandheating,airpurifiers,electronicrefrigerator,LCDmonitor,LEDlighting,communicationsequipment,audio-visualproducts,security,computerchassis,digitalproductsandequipmentandotherfields.IntroductionWiththerapiddevelopmentofpowerelectronicstechnology,powerelectronicsequipmentandpeople'swork,therelationshipoflifebecomeincreasinglyclose,andelectronicequipmentwithoutreliablepower,intothe1980s,computerpowerandthefullrealizationoftheswitchingpowersupply,thefirsttocompletethecomputerPowernewgenerationtoentertheswitchingpowersupplyinthe1990shaveenteredintoavarietyofelectronic,electricaldevices,program-controlledswitchboards,communications,electronictestingequipmentpowercontrolequipment,powersupply,etc.havebeenwidelyusedinswitchingpowersupply,butalsotopromotetherapiddevelopmentoftheswitchingpowersupplytechnology.Switchingpowersupplyistheuseofmodernpowerelectronicstechnologytocontroltheratiooftheswitchingtransistortoturnonandofftomaintainastableoutputvoltagepowersupply,switchingpowersupplyisgenerallycontrolledbypulsewidthmodulation(PWM)ICsandswitchingdevices(MOSFET,BJT)composition.Switchingpowersupplyandlinearpowercomparedtoboththecostandgrowthwiththeincreaseofoutputpower,butthetwodifferentgrowthrates.Apowerpoint,linearpowersupplycosts,buthigherthantheswitchingpowersupply.Withthedevelopmentofpowerelectronicstechnologyandinnovation,makingtheswitchingpowersupplytechnologytocontinuetoinnovate,theturningpointsofthiscostisincreasinglymovetothelowoutputpowerside,theswitchingpowersupplyprovidesabroadspacefordevelopment.Thedirectionofitsdevelopmentisthehigh-frequencyswitchingpowersupply,highfrequencyswitchingpowersupplyminiaturization,andswitchingpowersupplyintoawiderrangeofapplicationareas,especiallyinhigh-techfields,andpromotetheminiaturizationofhigh-techproducts,lightof.Inaddition,thedevelopmentandapplicationoftheswitchingpowersupplyintermsofenergyconservation,resourceconservationandenvironmentalprotectionareofgreatsignificance.3、ClassificationModernswitchingpowersupply,therearetwo:oneistheDCswitchingpowersupply;theotheristheACswitchingpowersupply.IntroducesonlyDCswitchingpowersupplyanditsfunctionispoorpowerqualityoftheoriginaleco-power(coarse)-suchasmainspowerorbatterypower,convertedtomeettheequipmentrequirementsofhigh-qualityDCvoltage(Varitronix).ThecoreoftheDCswitchingpowersupplyDC/DCconverter.DCswitchingpowersupplyclassificationisdependentontheclassificationofDC/DCconverter.Inotherwords,theclassificationoftheclassificationoftheDCswitchingpowersupplyandDC/DCconverteristheclassificationofessentiallythesame,theDC/DCconverterisbasicallyaclassificationoftheDCswitchingpowersupply.DC/DCconverterbetweentheinputandoutputelectricalisolationcanbedividedintotwocategories:oneisisolatedcalledisolatedDC/DCconverter;theotherisnotisolatedasnon-isolatedDC/DCconverter.IsolatedDC/DCconvertercanalsobeclassifiedbythenumberofactivepowerdevices.ThesingletubeofDC/DCconverterForward(Forward),Feedback(Feedback)two.Thedouble-barreleddouble-barreledDC/DCconverterForward(DoubleTransistorForwardConverter),twin-tubefeedback(DoubleTransistorFeedbackConverter),Push-Pull(PushthePullConverter)andhalf-bridge(Half-BridgeConverter)four.FourDC/DCconverteristhefull-bridgeDC/DCconverter(Full-BridgeConverter).Non-isolatedDC/DCconverter,accordingtothenumberofactivepowerdevicescanbedividedintosingle-tube,doublepipe,andfourthreecategories.SingletubetoatotalofsixoftheDC/DCconverter,step-down(Buck)DC/DCconverter,step-up(Boost)DC/DCconverters,DC/DCconverter,boostbuck(BuckBoost)deviceofCuktheDC/DCconverter,theZetaDC/DCconverterandSEPIC,theDC/DCconverter.DC/DCconverters,theBuckandBoosttypeDC/DCconverteristhebasicbuck-boostofCuk,Zeta,SEPIC,typeDC/DCconverterisderivedfromasingletubeinthissix.Thetwin-tubecascadeddouble-barreledboost(buck-boost)DC/DCconverterDC/DCconverter.FourDC/DCconverterisused,thefull-bridgeDC/DCconverter(Full-BridgeConverter).IsolatedDC/DCconverterinputandoutputelectricalisolationisusuallytransformertoachievethefunctionofthetransformerhasatransformer,soconducivetotheexpansionoftheconverteroutputrangeofapplications,butalsoeasytoachievedifferentvoltageoutput,oravarietyofthesamevoltageoutput.Powerswitchvoltageandcurrentrating,theconverter'soutputpowerisusuallyproportionaltothenumberofswitch.Themorethenumberofswitch,thegreatertheoutputpoweroftheDC/DCconverter,fourtypethanthetwooutputpoweristwiceaslarge,single-tubeoutputpowerofonlyfour1/4.Acombinationofnon-isolatedconvertersandisolatedconverterscanbeasingleconverterdoesnothavetheirowncharacteristics.Energytransmissionpoints,one-waytransmissionandtwo-waytransmissionoftwoDC/DCconverter.DC/DCconverterwithbi-directionaltransmissionfunction,eithersideofthetransmissionpowerfromthepoweroflateralloadpowerfromtheload-lateralsideofthetransmissionpower.DC/DCconvertercanbedividedintoself-excitedandseparatelycontrolled.Withthepositivefeedbacksignalconvertertoswitchtoself-sustainingperiodicswitchingconverter,calledself-excitedconverter,suchasthetheLuoYeer(Royer,)converterisatypicalpush-pullself-oscillatingconverter.ControlledDC/DCconverterswitchingdevicecontrolsignalisgeneratedbyspecializedexternalcontrolcircuit.4、Theswitchingpowersupply.Peopleinthefieldofswitchingpowersupplytechnologysideofthedevelopmentofpowerelectronicdevices,whilethedevelopmentoftheswitchinginvertertechnology,thetwopromoteeachothertopromotetheswitchingpowersupplyannualgrowthrateofmorethantwodigitstowardthelight,small,thin,low-noise,highreliability,thedirectionofdevelopmentofanti-jamming.SwitchingpowersupplycanbedividedintoAC/DCandDC/DCtwocategories,AC/ACDC/AC,suchasinverters,DC/DCconverterisnowmodulardesigntechnologyandproductionprocessesathomeandabroadhavealreadymaturedandstandardization,andhasbeenrecognizedbytheuser,butAC/DCmodular,itsowncharacteristicsmakethemodularprocess,encountermorecomplextechnologyandmanufacturingprocess.Hereinaftertoillustratethestructureandcharacteristicsofthetwotypesofswitchingpowersupply.Self-excited:noexternalsignalsourcecanbeself-oscillation,completelyself-excitedtoseeitasfeedbackoscillationcircuitofatransformer.Separateexcitation:entirelydependentonexternalsustainoscillations,excitedusedwidelyinpracticalapplications.Accordingtotheexcitationsignalstructureclassification;canbedividedintopulse-width-modulatedandpulseamplitudemodulatedtwopulsewidthmodulatedcontrolthewidthofthesignalisfrequency,pulseamplitudemodulationcontrolsignalamplitudebetweenthesameeffectaretheoscillationfrequencytomaintainwithinacertainrangetoachievetheeffectofvoltagestability.Thewindingofthetransformercangenerallybedividedintothreetypes,onegroupisinvolvedintheoscillationoftheprimarywinding,agroupofsustainedoscillationsinthefeedbackwinding,thereisagroupofloadwinding.SuchasShanghaiisusedinhouseholdappliancesarttechnologicalproductionofswitchingpowersupply,220VACbridgerectifier,changingtoabout300VDCfilteraddedtothecollectoroftheswitchintothetransformerforhighfrequencyoscillation,thefeedbackwindingfeedbacktothebasetomaintainthecircuitoscillatingloadwindinginductionsignal,theDCvoltagebytherectifier,filter,regulatortoprovidepowertotheload.Loadwindingtoprovidepoweratthesametime,takeuptheabilitytovoltagestability,theprincipleisthevoltageoutputcircuitconnectedtoavoltagesamplingdevicetomonitortheoutputvoltagechanges,andtimelyfeedbacktotheoscillatorcircuittoadjusttheoscillationfrequency,soastoachievestablevoltagepurposes,inordertoavoidtheinterferenceofthecircuit,thefeedbackvoltagebacktotheoscillatorcircuitwithoptocouplerisolation.5、technologydevelopmentsThehigh-frequencyswitchingpowersupplyisthedirectionofitsdevelopment,high-frequencyswitchingpowersupplyminiaturization,andswitchingpowersupplyintothebroaderfieldofapplication,especiallyinhigh-techfields,andpromotethedevelopmentandadvancementoftheswitchingpowersupply,anannualmorethantwo-digitgrowthratetowardthelight,small,thin,lownoise,highreliability,thedirectionoftheanti-jamming.SwitchingpowersupplycanbedividedintoAC/DCandDC/DCtwocategories,theDC/DCconverterisnowmodulardesigntechnologyandproductionprocessesathomeandabroadhavealreadymaturedandstandardized,andhasbeenrecognizedbytheuser,butmodularAC/DC,becauseofitsowncharacteristicsmakesthemodularprocess,encountermorecomplextechnologyandmanufacturingprocess.Inaddition,thedevelopmentandapplicationoftheswitchingpowersupplyintermsofenergyconservation,resourceconservationandenvironmentalprotectionareofgreatsignificance.Theswitchingpowersupplyapplicationsinpowerelectronicdevicesasdiodes,IGBTandMOSFET.SCRswitchingpowersupplyinputrectifiercircuitandsoftstartcircuit,asmallamountofapplications,theGTRdrivedifficult,lowswitchingfrequency,graduallyreplacetheIGBTandMOSFET.Directionofdevelopmentoftheswitchingpowersupplyisahigh-frequency,highreliability,lowpower,lownoise,jammingandmodular.Small,thin,andthekeytechnologyisthehighfrequencyswitchingpowersupplylight,soforeignmajorswitchingpowersupplymanufacturershavecommittedtosynchronizethedevelopmentofnewintelligentcomponents,inparticular,istoimprovethesecondaryrectifierloss,andthepowerofironOxygenmaterialstoincreasescientificandtechnologicalinnovationinordertoimprovethemagneticpropertiesofhighfrequencyandlargemagneticfluxdensity(Bs),andcapacitorminiaturizationisakeytechnology.SMTtechnologyallowstheswitchingpowersupplyhasmadeconsiderableprogress,thearrangementofthecomponentsinthecircuitboardonbothsides,toensurethatthelightoftheswitchingpowersupply,asmall,thin.High-frequencyswitchingpowersupplyisboundtothetraditionalPWMswitchingtechnologyinnovation,realizationofZVS,ZCSsoft-switchingtechnologyhasbecomethemainstreamtechnologyoftheswitchingpowersupply,andasubstantialincreaseintheefficiencyoftheswitchingpowersupply.Indicatorsforhighreliability,switchingpowersupplymanufacturersintheUnitedStatesbyreducingtheoperatingcurrent,reducingthejunctiontemperatureandothermeasurestoreducethestressofthedevice,greatlyimprovethereliabilityofproducts.Modularityistheoveralltrendofswitchingpowersupply,distributedpowersystemscanbecomposedofmodularpowersupply,canbedesignedtoN+1redundantpowersystem,andtheparallelcapacityexpansion.Forthisshortcomingoftheswitchingpowersupplyrunningnoise,separatethepursuitofhighfrequencynoisewillalsoincrease,whiletheuseofpartoftheresonantconvertercircuittechnologytoachievehighfrequency,intheory,butalsoreducenoise,butsomeThepracticalapplicationoftheresonantconvertertechnology,therearestilltechnicalproblems,itisstillalotofworkinthisfield,sothatthetechnologytobepractical.Powerelectronicstechnologyinnovation,switchingpowersupplyindustryhasbroadprospectsfordevelopment.ToacceleratethepaceofdevelopmentoftheswitchingpowersupplyindustryinChina,itmusttaketheroadoftechnologicalinnovation,outofjointproductionandresearchdevelopmentpathwithChinesecharacteristicsandcontributetotherapiddevelopmentofChina'snationaleconomy.1955U.S.Royer(Roger)inventedtheself-oscillatingpush-pulltransistorsingle-transformerDC-DCconverteristhebeginningofthehigh-frequencyconversioncontrolcircuit1957checkraceJen,Sen,inventedaself-oscillatingpush-pulldualtransformers,1964,U.S.scientistscanceledfrequencytransformerinseriestheideaofswitchingpowersupply,thepowersupplytothesizeandweightofthedeclineinafundamentalway.1969increasedduetothepressureofthehigh-powersilicontransistor,diodereverserecoverytimeshortenedandothercomponentstoimprove,andfinallymadea25-kHzswitchingpowersupply.Atpresent,theswitchingpowersupplytothesmall,lightweightandhighefficiencycharacteristicsarewidelyusedinavarietyofcomputer-orientedterminalequipment,communicationsequipment,etc.Almostallelectronicequipmentisindispensableforarapiddevelopmentoftoday'selectronicinformationindustrypowermode.Bipolartransistormadeof100kHz,500kHzpowerMOS-FETmade,thoughalreadythepracticalswitchingpowersupplyiscurrentlyavailableonthemarket,butitsfrequencytobefurtherimproved.Toimprovetheswitchingfrequency,itisnecessarytoreducetheswitchinglosses,andtoreducetheswitchinglosses,theneedforhigh-speedswitchcomponents.However,theswitchingspeedwillbeaffectedbythedistributionofthechargestoredintheinductanceandcapacitance,ordiodecircuittoproduceasurgeornoise.Thiswillnotonlyaffectthesurroundingelectronicequipment,butalsogreatlyreducethereliabilityofthepowersupplyitself.Which,inordertopreventtheswitchingKai-closedthevoltagesurge,RCorLCbufferscanbeused,andthecurrentsurgecanbecausedbythediodestoredchargeofamorphousandothercoremadeofmagneticbuffer.However,thehighfrequencymorethan1MHz,theresonantcircuittomaketheswitchonthevoltageorcurrentthroughtheswitchwasasinewave,whichcanreduceswitchinglosses,butalsotocontroltheoccurrenceofsurges.Thisswitchiscalledtheresonantswitch.Ofthisswitchingpowersupplyisactive,youcan,intheory,becauseinthiswaydonotneedtogreatlyimprovetheswitchingspeedoftheswitchinglossesreducedtozero,andthenoiseisexpectedtobecomeoneofthehigh-frequencyswitchingpowersupplyThemainways.Atpresent,manycountriesintheworldarecommittedtoseveraltrillionHzconverterutility.6、TheprincipleofIntroductionTheswitchingpowersupplyoftheprocessisquiteeasytounderstand,linearpowersupplies,powertransistorsoperatinginthelinearmodeandlinearpower,thePWMswitchingpowersupplytothepowertransistorturnsonandoffstate,inbothstates,onthepowertransistorV-securityproductisverysmall(conduction,lowvoltage,largecurrent;shutdown,voltage,current)Voltammetricproduct/powerdeviceispowersemiconductordevicesontheloss.Comparedwiththelinearpowersupply,thePWMswitchingpowersupplymoreefficientprocessisachievedby"chopping",thatiscutintotheamplitudeoftheinputDCvoltageequaltotheinputvoltageamplitudeofthepulsevoltage.Thepulsedutycycleisadjustedbytheswitchingpowersupplycontroller.OncetheinputvoltageiscutintotheACsquarewave,itsamplitudethroughthetransformertoraiseorlower.Numberofgroupsofoutputvoltagecanbeincreasedbyincreasingthenumberofprimaryandsecondarywindingsofthetransformer.AfterthelastACwaveformaftertherectifierfiltertheDCoutputvoltage.Themainpurposeofthecontrolleristomaintainthestabilityoftheoutputvoltage,thecourseoftheirworkisverysimilartothelinearformofthecontroller.Thatisthefunctionblocksofthecontroller,thevoltagereferenceanderroramplifiercanbedesignedthesameasthelinearregulator.Theirdifferenceliesintheerroramplifieroutput(errorvoltage)inthedrivebeforethepowertubetogothroughavoltage/pulse-widthconversionunit.SwitchingpowersupplyTherearetwomainwaysofworking:Forwardtransformandboosttransformation.Althoughtheyareallpartofthelayoutdifferenceissmall,butthecourseoftheirworkvarygreatly,haveadvantagesinspecificapplications.7、ThecircuitschematicTheso-calledswitchingpowersupply,asthenameimplies,isadoor,adoorpowerthroughaclosedpowertostopby,thenwhatisthedoor,theswitchingpowersupplyusingSCR,someswitch,thesetwocomponentperformanceissimilar,arerelyingonthebaseswitchcontrolpole(SCR),coupledwiththepulsesignaltocompletetheonandoff,thepulsesignalishalfattentivetocontrolthepolevoltageincreases,theswitchortransistorconduction,thefilteroutputvoltageof300V,220Vrectifierconduction,transmittedthroughtheswitchingtransformersecondarythroughthetransformertothevoltageincreaseordecreaseforeachcircuitwork.Oscillationpulseofnegativesemi-attentivetothepowerregulator,base,orSCRcontrolvoltagelowerthantheoriginalsetvoltagepowerregulatorcut-off,300Vpowerisoff,switchthetransformersecondarynovoltage,theneachcircuitTherequiredoperatingvoltage,dependsonthissecondaryroadrectifierfiltercapacitordischargetomaintain.Repeattheprocessuntilthenextpulsecycleisahalfweekswhenthesignalarrival.Thisswitchtransformeriscalledthehigh-frequencytransformer,becausetheoperatingfrequencyishigherthanthe50HZlowfrequency.ThenpromotethepulseoftheswitchorSCR,whichrequirestheoscillatorcircuit,weknow,thetransistorhasacharacteristic,isthebase-emittervoltageis0.65-0.7Visthezoomstate,0.7VThesearethesaturatedhydraulicconductivitystate-0.1V-0.3Vintheoscillatorystate,thentheoperatingpointafteragoodtune,torelyonthedeepnegativefeedbacktogenerateanegativepressure,sothattheoscillatingtubeonset,thefrequencyoftheoscillatingtubecapacitorcharginganddischargingofthelengthoftimefromthebasetodeterminetheoscillationfrequencyoftheoutputpulseamplitude,andviceversaonthesmall,whichdeterminesthesizeoftheoutputvoltageofthepowerregulator.Transformersecondaryoutputvoltageregulator,usuallyswitchingtransformer,singlearoundasetofcoils,thevoltageatitsupperend,asthereferencevoltageaftertherectifierfilter,thenthroughtheoptocoupler,thisbenchmarkvoltagereturntothebaseoftheoscillatingtubepoletoadjusttheleveloftheoscillationfrequency,訐thetransformersecondaryvoltageisincreased,thesamplingcoiloutputvoltageincreases,thepositivefeedbackvoltageobtainedthroughtheoptocouplerisalsoincreased,thisvoltageisappliedoscillatingtubebase,sothatoscillationfrequencyisreduced,playedastablesecondaryoutputvoltagestability,toosmalldonothavetogointodetail,noritisnecessarytounder