儀表知(zhi)識：開關電源的分(fen)類及基本框架

我(wo)們在采購儀表(biao)(biao)的(de)時(shi)候經常看(kan)到(dao)儀表(biao)(biao)說明書上注明工(gong)作電(dian)源(yuan)是開(kai)關電(dian)源(yuan)。開(kai)關電(dian)源(yuan)我(wo)們不怎么理解。到(dao)底有什么好(hao)處。今天(tian)虹潤儀表(biao)(biao)從(cong)開(kai)關電(dian)源(yuan)的(de)3個特(te)點來進(jin)行分析下。

開關電源(yuan)電路

開(kai)關(guan)電(dian)源(yuan)是(shi)相對(dui)線性電(dian)源(yuan)來說的一種穩壓電(dian)源(yuan)，全(quan)稱為開(kai)關(guan)式穩壓電(dian)源(yuan)，是(shi)20世紀70 年代發展起來的(de)、用來替代老式串(chuan)聯型穩壓電(dian)源的(de)一(yi)(yi)種(zhong)新型電(dian)源。它(ta)是通過(guo)開(kai)關電(dian)源厚膜(mo)塊控制開(kai)關管進行高速的(de)通斷(duan)與截止(zhi)，將(jiang)直流電(dian)轉換為高頻率的(de)交流電(dian)，提(ti)供(gong)給變壓器進行變壓，從而產生所需要的(de)一(yi)(yi)組或多組電(dian)壓的(de)一(yi)(yi)種(zhong)供(gong)電(dian)電(dian)路。

開關電(dian)(dian)源是(shi)直接對(dui)電(dian)(dian)網(wang)電(dian)(dian)壓進行(xing)整流濾波調(diao)整，然后由(you)開關調(diao)整管進行(xing)穩(wen)壓，不需要電(dian)(dian)源變壓器(qi)。它用(yong)開關管作為開關器(qi)件，通過(guo)控制開關的(de)占空比(bi)調(diao)整輸出電(dian)(dian)壓，是(shi)一個電(dian)(dian)壓深度(du)負反饋的(de)脈沖寬(kuan)度(du)調(diao)制器(qi)（pwm），其功率(lv)器件工作(zuo)(zuo)于開關(guan)狀態，因此功率(lv)器件功耗低、效率(lv)高。而且開關(guan)管(guan)的工作(zuo)(zuo)頻率(lv)在幾十千赫(he)以上，濾波電(dian)(dian)容(rong)器和電(dian)(dian)感器容(rong)量較(jiao)小，因此開關(guan)電(dian)(dian)源(yuan)具有質量輕、體積小等(deng)特(te)點(dian)。

開關(guan)電源的分(fen)類(lei)

開(kai)關(guan)(guan)(guan)電(dian)(dian)源(yuan)的(de)(de)種(zhong)類(lei)較多，可根(gen)據不(bu)同(tong)標準進行基本分(fen)類(lei)。開(kai)關(guan)(guan)(guan)電(dian)(dian)源(yuan)根(gen)據電(dian)(dian)源(yuan)儲(chu)能電(dian)(dian)感與負載的(de)(de)連(lian)接方(fang)式(shi)可基本劃分(fen)為(wei)串聯(lian)型(xing)(xing)開(kai)關(guan)(guan)(guan)電(dian)(dian)源(yuan)和(he)并聯(lian)型(xing)(xing)開(kai)關(guan)(guan)(guan)電(dian)(dian)源(yuan)；按(an)(an)照控制(zhi)(zhi)開(kai)關(guan)(guan)(guan)管的(de)(de)導通方(fang)式(shi)可分(fen)為(wei)調寬(kuan)型(xing)(xing)、調頻型(xing)(xing)和(he)混合調制(zhi)(zhi)型(xing)(xing)；按(an)(an)電(dian)(dian)源(yuan)啟(qi)動方(fang)式(shi)可分(fen)為(wei)自激型(xing)(xing)和(he)他激型(xing)(xing)兩種(zhong)；按(an)(an)開(kai)關(guan)(guan)(guan)管的(de)(de)類(lei)型(xing)(xing)可分(fen)為(wei)晶(jing)體管型(xing)(xing)開(kai)關(guan)(guan)(guan)電(dian)(dian)源(yuan)和(he)晶(jing)閘管型(xing)(xing)開(kai)關(guan)(guan)(guan)電(dian)(dian)源(yuan)；按(an)(an)開(kai)關(guan)(guan)(guan)管的(de)(de)連(lian)接方(fang)式(shi)可分(fen)為(wei)單(dan)端式(shi)、推(tui)挽式(shi)、半橋式(shi)和(he)全橋式(shi)四種(zhong)。

目(mu)前開(kai)(kai)關(guan)(guan)(guan)電(dian)(dian)(dian)(dian)源(yuan)的應用大多是(shi)幾(ji)(ji)種(zhong)類型的開(kai)(kai)關(guan)(guan)(guan)電(dian)(dian)(dian)(dian)源(yuan)的組合(he)。根據開(kai)(kai)關(guan)(guan)(guan)電(dian)(dian)(dian)(dian)源(yuan)的不同組合(he)，可分(fen)別組合(he)出自(zi)激(ji)(ji)并聯(lian)調(diao)(diao)頻(pin)(pin)式(shi)(shi)開(kai)(kai)關(guan)(guan)(guan)電(dian)(dian)(dian)(dian)源(yuan)、自(zi)激(ji)(ji)串(chuan)聯(lian)調(diao)(diao)頻(pin)(pin)式(shi)(shi)開(kai)(kai)關(guan)(guan)(guan)電(dian)(dian)(dian)(dian)源(yuan)、他(ta)激(ji)(ji)串(chuan)聯(lian)調(diao)(diao)寬式(shi)(shi)開(kai)(kai)關(guan)(guan)(guan)電(dian)(dian)(dian)(dian)源(yuan)、自(zi)激(ji)(ji)并聯(lian)調(diao)(diao)寬式(shi)(shi)開(kai)(kai)關(guan)(guan)(guan)電(dian)(dian)(dian)(dian)源(yuan)和他(ta)激(ji)(ji)式(shi)(shi)串(chuan)聯(lian)調(diao)(diao)頻(pin)(pin)式(shi)(shi)開(kai)(kai)關(guan)(guan)(guan)電(dian)(dian)(dian)(dian)源(yuan)等幾(ji)(ji)種(zhong)。目(mu)前應用較多的主要有自(zi)激(ji)(ji)并聯(lian)調(diao)(diao)寬式(shi)(shi)開(kai)(kai)關(guan)(guan)(guan)電(dian)(dian)(dian)(dian)源(yuan)、自(zi)激(ji)(ji)并聯(lian)調(diao)(diao)頻(pin)(pin)式(shi)(shi)開(kai)(kai)關(guan)(guan)(guan)電(dian)(dian)(dian)(dian)源(yuan)、他(ta)激(ji)(ji)并聯(lian)調(diao)(diao)寬式(shi)(shi)開(kai)(kai)關(guan)(guan)(guan)電(dian)(dian)(dian)(dian)源(yuan)和自(zi)激(ji)(ji)串(chuan)聯(lian)調(diao)(diao)寬式(shi)(shi)開(kai)(kai)關(guan)(guan)(guan)電(dian)(dian)(dian)(dian)源(yuan)幾(ji)(ji)種(zhong)。

開關電源的基本框架

開關(guan)電(dian)(dian)源的(de)基本框架如圖(tu)所示(shi)，主要(yao)由交流(liu)進線電(dian)(dian)路(lu)(lu)、整流(liu)電(dian)(dian)路(lu)(lu)、開關(guan)振蕩(dang)電(dian)(dian)路(lu)(lu)、脈沖整流(liu)電(dian)(dian)路(lu)(lu)、取(qu)樣比較(jiao)電(dian)(dian)路(lu)(lu)、脈寬控(kong)制電(dian)(dian)路(lu)(lu)、整流(liu)輸出電(dian)(dian)路(lu)(lu)和保護(hu)電(dian)(dian)路(lu)(lu)等組成。

開關電(dian)源各部(bu)分組(zu)成電(dian)路的(de)功能如下(xia):整流電路,負責(ze)把電網輸入的交流電變換成直(zhi)流電;開關振蕩電路,利用三極管的開關作用組(zu)成自激或(huo)他激式高頻振蕩;脈沖整流電路,對(dui)振蕩脈沖進行(xing)再整流;取樣(yang)比較(jiao)電路,把輸出的直(zhi)流電壓與(yu)電壓基準(zhun)進(jin)行比較(jiao),以獲得誤差電壓輸出;脈(mo)寬控制電路,對誤(wu)差電(dian)壓進行放(fang)大,控制(zhi)開關(guan)三(san)極(ji)管的導(dao)通和截止時間;整流輸出電路(lu),將變壓器輸出(chu)的交流電變換為(wei)直流電輸出(chu)。

保(bao)護電(dian)路(lu),當開關電源存在過壓(ya)、過流、短路等故障時,使振蕩電(dian)路停振,開關管(guan)不工作(zuo),從而達(da)到保(bao)護(hu)開關電(dian)源(yuan)的目的。

通(tong)過上(shang)面的分析 虹潤(run)儀(yi)(yi)表希望可(ke)以給(gei)您采購(gou)儀(yi)(yi)器儀(yi)(yi)表時有所幫助。