什么叫開關電源?
如今(jin)隨著電(dian)(dian)力(li)電(dian)(dian)子(zi)技術(shu)的(de)(de)開(kai)(kai)放和發展(zhan)創(chuang)新(xin),使得開(kai)(kai)關(guan)電(dian)(dian)源(yuan)(yuan)技術(shu)也在不斷地發展(zhan)。現在,開(kai)(kai)關(guan)電(dian)(dian)源(yuan)(yuan)以小型、輕量和高功率的(de)(de)特(te)征被廣(guang)泛應用幾乎(hu)一切(qie)的(de)(de)電(dian)(dian)子(zi)設備,是當今(jin)電(dian)(dian)子(zi)信息(xi)產(chan)業飛速打開(kai)(kai)不行缺(que)少的(de)(de)一種電(dian)(dian)源(yuan)(yuan)方案(an)。
開(kai)關(guan)(guan)電(dian)(dian)源(yuan)是運用現代電(dian)(dian)力電(dian)(dian)子技術(shu),操控(kong)開(kai)關(guan)(guan)管注冊和關(guan)(guan)斷的(de)(de)時刻(ke)比率(lv),保持安(an)穩輸出電(dian)(dian)壓的(de)(de)一種(zhong)電(dian)(dian)源(yuan),開(kai)關(guan)(guan)電(dian)(dian)源(yuan)一般(ban)由(you)脈沖寬度調制(PWM)操控(kong)IC和MOSFET構成。
開關(guan)電(dian)(dian)源是相對線性電(dian)(dian)源說的(de),其輸(shu)入端(duan)直(zhi)接將交(jiao)流(liu)(liu)電(dian)(dian)整流(liu)(liu)變成直(zhi)流(liu)(liu)電(dian)(dian),再在(zai)高(gao)頻(pin)震動電(dian)(dian)路(lu)的(de)效果下(xia)(xia),用開關(guan)管操控(kong)電(dian)(dian)流(liu)(liu)的(de)通(tong)斷,構(gou)成高(gao)頻(pin)脈沖電(dian)(dian)流(liu)(liu)。在(zai)電(dian)(dian)感(gan)(高(gao)頻(pin)變壓(ya)器(qi))的(de)幫助(zhu)下(xia)(xia),輸(shu)出安穩(wen)的(de)低(di)壓(ya)直(zhi)流(liu)(liu)電(dian)(dian)。
因(yin)為(wei)變壓器(qi)的(de)(de)磁芯大(da)小(xiao)與開關電(dian)(dian)源作(zuo)業頻(pin)率(lv)的(de)(de)平方成反比(bi),頻(pin)率(lv)越高鐵(tie)心越小(xiao)。這(zhe)樣就能夠大(da)大(da)減小(xiao)變壓器(qi),使電(dian)(dian)源減輕重量和體積。而且因(yin)為(wei)它直接(jie)操(cao)控(kong)直流(liu),使這(zhe)種電(dian)(dian)源的(de)(de)功率(lv)比(bi)線性電(dian)(dian)源高許多(duo)。這(zhe)樣就節省了(le)動力,因(yin)此它遭到人們(men)的(de)(de)喜(xi)愛。但它也有缺點,便是電(dian)(dian)路(lu)凌亂,修理困難(nan),對(dui)電(dian)(dian)路(lu)的(de)(de)污染嚴峻。電(dian)(dian)源噪聲(sheng)大(da),不適合用于某些低噪聲(sheng)電(dian)(dian)路(lu)。
開關電源的特征
開關電(dian)源(yuan)一(yi)般(ban)由脈沖(chong)寬度調制(zhi)(PWM)操控IC和(he)MOSFET構成(cheng)。跟著跟著電(dian)力電(dian)子技術的(de)打開和(he)立(li)異,現在開關電(dian)源(yuan)首要(yao)以小型(xing)、輕(qing)量和(he)高功(gong)率的(de)特征被(bei)廣泛(fan)應用到幾乎一(yi)切的(de)電(dian)子設備,其重要(yao)性可(ke)見一(yi)斑。
開關電源的分類
根據開(kai)關器(qi)材在電(dian)(dian)(dian)路中連接的(de)方案,開(kai)關電(dian)(dian)(dian)源(yuan)總的(de)來(lai)說(shuo)可分為(wei)串聯(lian)式(shi)開(kai)關電(dian)(dian)(dian)源(yuan)、并聯(lian)式(shi)開(kai)關電(dian)(dian)(dian)源(yuan)、變壓(ya)器(qi)式(shi)開(kai)關電(dian)(dian)(dian)源(yuan)等三大類(lei)。
其間,變壓器(qi)(qi)式(shi)(shi)開關電源還能(neng)夠(gou)進(jin)一步分紅:推挽式(shi)(shi)、半橋(qiao)式(shi)(shi)、全橋(qiao)式(shi)(shi)等多(duo)種。根據(ju)變壓器(qi)(qi)的(de)鼓(gu)舞和輸(shu)出電壓的(de)相位(wei),又(you)能(neng)夠(gou)分紅:正激式(shi)(shi)、反激式(shi)(shi)、單激式(shi)(shi)和雙激式(shi)(shi)等多(duo)種。
開關電源(yuan)(yuan)和一般電源(yuan)(yuan)的(de)差異
一般(ban)的電(dian)(dian)源一般(ban)是線性電(dian)(dian)源,線性電(dian)(dian)源,是指調整(zheng)管(guan)作業在線性狀況(kuang)下的電(dian)(dian)源。而在開(kai)(kai)關(guan)(guan)電(dian)(dian)源中(zhong)則(ze)不相同,開(kai)(kai)關(guan)(guan)管(guan)(在開(kai)(kai)關(guan)(guan)電(dian)(dian)源中(zhong),咱們一般(ban)把調整(zheng)管(guan)叫做(zuo)開(kai)(kai)關(guan)(guan)管(guan))是作業在開(kai)(kai)、關(guan)(guan)兩種狀況(kuang)下的:開(kai)(kai)——電(dian)(dian)阻(zu)(zu)很小,關(guan)(guan)——電(dian)(dian)阻(zu)(zu)很大(da)。
開(kai)關電源是一種比(bi)較新式(shi)的(de)電源。它具有功(gong)(gong)率高,重量輕(qing),可升、降壓、輸出功(gong)(gong)率大等利益。但是因為(wei)電路(lu)作業在開(kai)關狀況,所以噪(zao)聲比(bi)較大。
舉例說明(ming):降壓型開(kai)關電源
咱們(men)來(lai)簡(jian)略的說說降壓型開關(guan)電(dian)源(yuan)的作業原(yuan)理:電(dian)路由開關(guan)(實際電(dian)路中為三極管或許場效應管),續流二(er)極管、儲能電(dian)感、濾波電(dian)容(rong)等構成。
當開(kai)(kai)關(guan)(guan)閉合時,電(dian)(dian)源經過開(kai)(kai)關(guan)(guan)、電(dian)(dian)感給負(fu)載供電(dian)(dian),并(bing)將部(bu)分電(dian)(dian)能儲存在電(dian)(dian)感以及電(dian)(dian)容中。因為(wei)電(dian)(dian)感的自感,在開(kai)(kai)關(guan)(guan)接通后,電(dian)(dian)流增大得比較(jiao)緩慢,即輸出不能馬上(shang)到達電(dian)(dian)源電(dian)(dian)壓值。
必(bi)定時刻后,開(kai)(kai)關斷開(kai)(kai),因(yin)為電(dian)(dian)(dian)感(gan)(gan)的(de)(de)自感(gan)(gan)效果(guo)(能夠比較形象(xiang)的(de)(de)認為電(dian)(dian)(dian)感(gan)(gan)中的(de)(de)電(dian)(dian)(dian)流(liu)有慣性(xing)效果(guo)),將堅持電(dian)(dian)(dian)路中的(de)(de)電(dian)(dian)(dian)流(liu)不變,即從左往(wang)右(you)繼(ji)續流(liu)。這電(dian)(dian)(dian)流(liu)流(liu)過(guo)負載,從地線回(hui)來,流(liu)到續流(liu)二(er)極管(guan)的(de)(de)正(zheng)極,經過(guo)二(er)極管(guan),回(hui)來電(dian)(dian)(dian)感(gan)(gan)的(de)(de)左端,然后構成了(le)一個回(hui)路。
經過(guo)操(cao)(cao)控(kong)開關(guan)閉合(he)跟斷(duan)開的(de)時(shi)(shi)刻(即PWM——脈(mo)沖寬(kuan)度調(diao)制),就(jiu)能夠操(cao)(cao)控(kong)輸(shu)(shu)出電(dian)壓(ya)。假如經過(guo)檢測輸(shu)(shu)出電(dian)壓(ya)來操(cao)(cao)控(kong)開、關(guan)的(de)時(shi)(shi)刻,以(yi)堅(jian)持輸(shu)(shu)出電(dian)壓(ya)不變(bian),這就(jiu)完成了穩壓(ya)的(de)目的(de)。
一(yi)般(ban)電(dian)(dian)源(yuan)和開關(guan)電(dian)(dian)源(yuan)相同的(de)是(shi)都(dou)有(you)電(dian)(dian)壓(ya)調(diao)整管(guan),運(yun)用(yong)反響原理來進行穩壓(ya)的(de),不同的(de)是(shi)開關(guan)電(dian)(dian)源(yuan)運(yun)用(yong)開關(guan)管(guan)進行調(diao)整,一(yi)般(ban)電(dian)(dian)源(yuan)一(yi)般(ban)運(yun)用(yong)三(san)極管(guan)的(de)線性放大區進行調(diao)整。比較而言,開關(guan)電(dian)(dian)源(yuan)的(de)能耗(hao)低,對交流(liu)電(dian)(dian)壓(ya)適用(yong)范圍要(yao)寬,輸出(chu)直流(liu)的(de)波紋系(xi)數要(yao)好,缺(que)點是(shi)開關(guan)脈沖煩擾。
一(yi)般半橋(qiao)開(kai)(kai)關(guan)電(dian)源的(de)(de)首(shou)要(yao)作業原(yuan)理便是上(shang)橋(qiao)和下橋(qiao)的(de)(de)開(kai)(kai)關(guan)管(guan)(guan)(guan)(頻率高時開(kai)(kai)關(guan)管(guan)(guan)(guan)為(wei)VMOS)輪番導通(tong),首(shou)要(yao)電(dian)流經(jing)過(guo)上(shang)橋(qiao)開(kai)(kai)關(guan)管(guan)(guan)(guan)流入,運(yun)用電(dian)感線圈的(de)(de)存儲功能(neng),將電(dian)能(neng)集聚在線圈中,畢竟關(guan)閉上(shang)橋(qiao)開(kai)(kai)關(guan)管(guan)(guan)(guan),翻開(kai)(kai)下橋(qiao)的(de)(de)開(kai)(kai)關(guan)管(guan)(guan)(guan),電(dian)感線圈和電(dian)容繼續給外部供電(dian)。然后又關(guan)閉下橋(qiao)開(kai)(kai)關(guan)管(guan)(guan)(guan),再翻開(kai)(kai)上(shang)橋(qiao)讓電(dian)流進(jin)入,就這樣重復進(jin)行,因(yin)為(wei)要(yao)輪番開(kai)(kai)關(guan)兩開(kai)(kai)關(guan)管(guan)(guan)(guan),所以(yi)稱為(wei)開(kai)(kai)關(guan)電(dian)源。
而(er)線性電(dian)(dian)(dian)源就不(bu)相同了,因為沒(mei)有開關介入,使得上(shang)水(shui)(shui)管(guan)一直(zhi)在放(fang)水(shui)(shui),假如有多(duo)的(de)(de),就會漏(lou)出來,這便是咱們常(chang)(chang)常(chang)(chang)看到(dao)的(de)(de)某些線性電(dian)(dian)(dian)源的(de)(de)調整管(guan)發(fa)熱量很大,用(yong)不(bu)完(wan)的(de)(de)電(dian)(dian)(dian)能,全部(bu)轉(zhuan)化成了熱能。從這個視點(dian)來看,線性電(dian)(dian)(dian)源的(de)(de)轉(zhuan)化功(gong)率(lv)就非(fei)常(chang)(chang)低了,而(er)且熱量高的(de)(de)時分,元件的(de)(de)壽數勢必要下降,影響畢(bi)竟的(de)(de)運用(yong)效果。
首要差異:作業方案
線(xian)性電源的(de)功率調(diao)整管(guan)(guan)總是作業(ye)在放大(da)區,流過的(de)電流是接連的(de)。因為調(diao)整管(guan)(guan)上損耗較大(da)的(de)功率,所以需求較大(da)功率調(diao)整管(guan)(guan)并裝有體積很大(da)的(de)散熱(re)(re)器(qi),發熱(re)(re)嚴峻,功率很低,一(yi)般在40%~60%(還得說是很好的(de)線(xian)性電源)。
線性電(dian)源的(de)作業(ye)方案,使從高壓(ya)(ya)(ya)變低(di)壓(ya)(ya)(ya)必須有(you)將壓(ya)(ya)(ya)裝置,一般的(de)都是變壓(ya)(ya)(ya)器,也(ye)有(you)其他像(xiang)KX電(dian)源,再經(jing)過整流輸出直流電(dian)壓(ya)(ya)(ya)。這樣一來體積(ji)也(ye)就很大(da),比較粗笨,功率低(di)、發(fa)熱量(liang)也(ye)大(da);但也(ye)有(you)利益:紋波(bo)小、調整率好(hao)、對外煩擾(rao)小、適(shi)合(he)用(yong)與模(mo)擬電(dian)路/各類放大(da)器等(deng)。
開(kai)關(guan)電(dian)(dian)源它的(de)功(gong)率(lv)(lv)器材作業在(zai)開(kai)關(guan)狀(zhuang)況(kuang),在(zai)電(dian)(dian)壓(ya)調整(zheng)時(shi)能量是(shi)(shi)經過電(dian)(dian)感線圈來暫時(shi)儲存,這樣他的(de)損耗就(jiu)(jiu)小(xiao),功(gong)率(lv)(lv)也(ye)就(jiu)(jiu)高,對散熱的(de)要(yao)(yao)求低,但它對變壓(ya)器和貯能電(dian)(dian)感也(ye)有了**的(de)要(yao)(yao)求,要(yao)(yao)用低損耗高磁導率(lv)(lv)的(de)材料來做。它的(de)變壓(ya)器便是(shi)(shi)一(yi)個(ge)字小(xiao)。總功(gong)率(lv)(lv)在(zai)80%~98%,開(kai)關(guan)電(dian)(dian)源的(de)功(gong)率(lv)(lv)高但體積小(xiao),但是(shi)(shi)和線性電(dian)(dian)源比他的(de)紋波,電(dian)(dian)壓(ya)電(dian)(dian)流(liu)調整(zheng)率(lv)(lv)就(jiu)(jiu)有必定(ding)的(de)折扣了。