什么叫開關電源?
如(ru)今(jin)隨(sui)著電力電子(zi)技術(shu)的(de)開放和發展創新,使得開關電源(yuan)技術(shu)也在(zai)不(bu)斷(duan)地發展。現在(zai),開關電源(yuan)以(yi)小(xiao)型、輕(qing)量和高功率的(de)特征(zheng)被廣(guang)泛應用幾(ji)乎一(yi)切的(de)電子(zi)設備,是當今(jin)電子(zi)信息產業飛速打開不(bu)行缺(que)少的(de)一(yi)種電源(yuan)方案。
開(kai)關(guan)電(dian)(dian)(dian)源是運用現代電(dian)(dian)(dian)力電(dian)(dian)(dian)子技(ji)術,操控開(kai)關(guan)管注冊和(he)關(guan)斷的時刻(ke)比(bi)率,保持安穩輸出電(dian)(dian)(dian)壓(ya)的一(yi)種電(dian)(dian)(dian)源,開(kai)關(guan)電(dian)(dian)(dian)源一(yi)般由脈沖寬(kuan)度調制(PWM)操控IC和(he)MOSFET構成。
開關電(dian)(dian)(dian)(dian)源是相對線性電(dian)(dian)(dian)(dian)源說(shuo)的(de),其輸入端直接將交流電(dian)(dian)(dian)(dian)整(zheng)流變成(cheng)直流電(dian)(dian)(dian)(dian),再在(zai)(zai)高(gao)頻震動電(dian)(dian)(dian)(dian)路的(de)效(xiao)果(guo)下,用開關管操控(kong)電(dian)(dian)(dian)(dian)流的(de)通斷,構成(cheng)高(gao)頻脈沖電(dian)(dian)(dian)(dian)流。在(zai)(zai)電(dian)(dian)(dian)(dian)感(高(gao)頻變壓(ya)器)的(de)幫助下,輸出安穩的(de)低(di)壓(ya)直流電(dian)(dian)(dian)(dian)。
因為(wei)變壓器(qi)的(de)(de)磁芯大小(xiao)與開關電(dian)源作業頻(pin)率的(de)(de)平方成反(fan)比,頻(pin)率越(yue)高鐵心越(yue)小(xiao)。這(zhe)樣就能夠大大減(jian)小(xiao)變壓器(qi),使電(dian)源減(jian)輕重量和體積。而(er)且因為(wei)它直接操控直流,使這(zhe)種(zhong)電(dian)源的(de)(de)功(gong)率比線性電(dian)源高許多。這(zhe)樣就節省(sheng)了動力,因此它遭到(dao)人們的(de)(de)喜愛(ai)。但它也有缺(que)點(dian),便是電(dian)路凌亂,修理困難,對電(dian)路的(de)(de)污染(ran)嚴峻。電(dian)源噪聲大,不適(shi)合用(yong)于某(mou)些低噪聲電(dian)路。
開關電源的特征
開(kai)關電(dian)(dian)源一(yi)般由脈(mo)沖寬度調制(PWM)操控IC和(he)(he)MOSFET構成。跟著(zhu)跟著(zhu)電(dian)(dian)力電(dian)(dian)子技術的打開(kai)和(he)(he)立(li)異,現在開(kai)關電(dian)(dian)源首要(yao)以(yi)小(xiao)型、輕(qing)量和(he)(he)高功率的特征被廣泛(fan)應(ying)用到幾乎(hu)一(yi)切的電(dian)(dian)子設備,其重(zhong)要(yao)性可(ke)見一(yi)斑(ban)。
開關電源的分類
根(gen)據開(kai)(kai)關(guan)(guan)器(qi)材在電(dian)路中連接的(de)方案,開(kai)(kai)關(guan)(guan)電(dian)源(yuan)總的(de)來說可分為串聯(lian)式(shi)開(kai)(kai)關(guan)(guan)電(dian)源(yuan)、并聯(lian)式(shi)開(kai)(kai)關(guan)(guan)電(dian)源(yuan)、變(bian)壓器(qi)式(shi)開(kai)(kai)關(guan)(guan)電(dian)源(yuan)等三大類(lei)。
其(qi)間,變壓器式(shi)開關電源還能(neng)夠進一步分紅:推挽式(shi)、半橋式(shi)、全橋式(shi)等多種。根(gen)據變壓器的鼓舞和輸出電壓的相(xiang)位,又能(neng)夠分紅:正(zheng)激式(shi)、反激式(shi)、單激式(shi)和雙激式(shi)等多種。
開關電源(yuan)和(he)一般電源(yuan)的(de)差異(yi)
一(yi)般的電(dian)(dian)(dian)源(yuan)一(yi)般是(shi)線性電(dian)(dian)(dian)源(yuan),線性電(dian)(dian)(dian)源(yuan),是(shi)指(zhi)調整(zheng)管(guan)作業在(zai)線性狀況下的電(dian)(dian)(dian)源(yuan)。而(er)在(zai)開(kai)關(guan)(guan)電(dian)(dian)(dian)源(yuan)中則(ze)不相同,開(kai)關(guan)(guan)管(guan)(在(zai)開(kai)關(guan)(guan)電(dian)(dian)(dian)源(yuan)中,咱們一(yi)般把(ba)調整(zheng)管(guan)叫(jiao)做開(kai)關(guan)(guan)管(guan))是(shi)作業在(zai)開(kai)、關(guan)(guan)兩(liang)種狀況下的:開(kai)——電(dian)(dian)(dian)阻很(hen)小(xiao),關(guan)(guan)——電(dian)(dian)(dian)阻很(hen)大。
開(kai)關(guan)電(dian)源是(shi)一種比(bi)較(jiao)(jiao)新式的(de)電(dian)源。它具有功率高,重量輕,可升、降(jiang)壓、輸出(chu)功率大等利益。但是(shi)因為電(dian)路作業在開(kai)關(guan)狀況(kuang),所以噪聲比(bi)較(jiao)(jiao)大。
舉例說明:降(jiang)壓型開關電源
咱們來簡(jian)略的說說降壓型(xing)開關電(dian)源的作業原理:電(dian)路(lu)由開關(實際電(dian)路(lu)中為三極(ji)管或許(xu)場效應管),續流二極(ji)管、儲能(neng)電(dian)感、濾波電(dian)容(rong)等構成。
當開關(guan)閉合時(shi),電(dian)源經(jing)過(guo)開關(guan)、電(dian)感(gan)給(gei)負載供電(dian),并將部分電(dian)能儲(chu)存在電(dian)感(gan)以及(ji)電(dian)容中。因(yin)為電(dian)感(gan)的自感(gan),在開關(guan)接(jie)通(tong)后,電(dian)流增(zeng)大得比較(jiao)緩(huan)慢(man),即輸出(chu)不能馬上到(dao)達電(dian)源電(dian)壓值。
必定時刻后,開(kai)關斷(duan)開(kai),因(yin)為電(dian)感的(de)自感效果(能夠比較形象的(de)認為電(dian)感中(zhong)的(de)電(dian)流(liu)有慣性效果),將堅持電(dian)路中(zhong)的(de)電(dian)流(liu)不變,即從左往(wang)右繼(ji)續流(liu)。這電(dian)流(liu)流(liu)過負載(zai),從地(di)線回來(lai),流(liu)到(dao)續流(liu)二(er)極管的(de)正極,經過二(er)極管,回來(lai)電(dian)感的(de)左端,然(ran)后構成了一個回路。
經過操(cao)控開關(guan)閉(bi)合跟斷開的時刻(即(ji)PWM——脈(mo)沖寬度調制),就(jiu)能夠操(cao)控輸出電(dian)壓。假如經過檢測(ce)輸出電(dian)壓來操(cao)控開、關(guan)的時刻,以(yi)堅持輸出電(dian)壓不變(bian),這就(jiu)完成了穩壓的目(mu)的。
一(yi)般電(dian)(dian)源(yuan)和開(kai)關(guan)電(dian)(dian)源(yuan)相同的(de)(de)是都有電(dian)(dian)壓(ya)調整(zheng)(zheng)管,運(yun)用反響原理來進(jin)行(xing)穩壓(ya)的(de)(de),不(bu)同的(de)(de)是開(kai)關(guan)電(dian)(dian)源(yuan)運(yun)用開(kai)關(guan)管進(jin)行(xing)調整(zheng)(zheng),一(yi)般電(dian)(dian)源(yuan)一(yi)般運(yun)用三(san)極管的(de)(de)線(xian)性放大區進(jin)行(xing)調整(zheng)(zheng)。比較而言,開(kai)關(guan)電(dian)(dian)源(yuan)的(de)(de)能(neng)耗(hao)低,對(dui)交流電(dian)(dian)壓(ya)適用范圍要(yao)寬,輸出直流的(de)(de)波紋系數要(yao)好,缺點是開(kai)關(guan)脈沖煩擾(rao)。
一般半橋(qiao)開關(guan)(guan)電(dian)(dian)源(yuan)的(de)首要(yao)(yao)作(zuo)業原理(li)便是上橋(qiao)和下橋(qiao)的(de)開關(guan)(guan)管(guan)(guan)(頻率高時開關(guan)(guan)管(guan)(guan)為(wei)VMOS)輪番導通,首要(yao)(yao)電(dian)(dian)流(liu)經過上橋(qiao)開關(guan)(guan)管(guan)(guan)流(liu)入,運用電(dian)(dian)感線(xian)圈(quan)的(de)存儲功能,將電(dian)(dian)能集聚在(zai)線(xian)圈(quan)中,畢竟關(guan)(guan)閉(bi)上橋(qiao)開關(guan)(guan)管(guan)(guan),翻開下橋(qiao)的(de)開關(guan)(guan)管(guan)(guan),電(dian)(dian)感線(xian)圈(quan)和電(dian)(dian)容繼續給外(wai)部供電(dian)(dian)。然后(hou)又(you)關(guan)(guan)閉(bi)下橋(qiao)開關(guan)(guan)管(guan)(guan),再(zai)翻開上橋(qiao)讓電(dian)(dian)流(liu)進入,就(jiu)這樣重復進行,因為(wei)要(yao)(yao)輪番開關(guan)(guan)兩(liang)開關(guan)(guan)管(guan)(guan),所以稱為(wei)開關(guan)(guan)電(dian)(dian)源(yuan)。
而線性電(dian)源就(jiu)不(bu)相同了(le)(le),因為(wei)沒有開關介入,使得上水(shui)管一直在放(fang)水(shui),假如有多(duo)的(de)(de)(de),就(jiu)會(hui)漏出(chu)來(lai)(lai),這便是(shi)咱們常常看到的(de)(de)(de)某些線性電(dian)源的(de)(de)(de)調整管發熱(re)量很大,用(yong)不(bu)完(wan)的(de)(de)(de)電(dian)能(neng),全部轉化成了(le)(le)熱(re)能(neng)。從這個(ge)視(shi)點來(lai)(lai)看,線性電(dian)源的(de)(de)(de)轉化功(gong)率就(jiu)非(fei)常低了(le)(le),而且熱(re)量高(gao)的(de)(de)(de)時(shi)分,元件的(de)(de)(de)壽數勢必要下降,影響畢竟的(de)(de)(de)運用(yong)效果。
首要差異:作業方案
線性電(dian)源的(de)(de)功(gong)率調(diao)整管(guan)總是(shi)作業在放大區,流過(guo)的(de)(de)電(dian)流是(shi)接連的(de)(de)。因(yin)為調(diao)整管(guan)上損耗較大的(de)(de)功(gong)率,所以需求較大功(gong)率調(diao)整管(guan)并裝有體積很(hen)大的(de)(de)散熱器,發熱嚴峻,功(gong)率很(hen)低,一(yi)般在40%~60%(還得(de)說(shuo)是(shi)很(hen)好的(de)(de)線性電(dian)源)。
線(xian)性電(dian)源(yuan)(yuan)的作業方案,使從(cong)高壓(ya)(ya)變低壓(ya)(ya)必須有將壓(ya)(ya)裝置,一般的都(dou)是變壓(ya)(ya)器,也有其他(ta)像KX電(dian)源(yuan)(yuan),再經過整流輸出直流電(dian)壓(ya)(ya)。這樣一來體積也就(jiu)很大(da),比較粗笨,功率低、發熱量也大(da);但也有利益:紋波(bo)小、調整率好、對外煩擾小、適(shi)合用與模擬電(dian)路(lu)/各(ge)類(lei)放(fang)大(da)器等。
開(kai)關電(dian)(dian)(dian)源它(ta)的(de)(de)功率(lv)器(qi)(qi)材作業(ye)在(zai)開(kai)關狀況(kuang),在(zai)電(dian)(dian)(dian)壓(ya)調整時(shi)能量是經過電(dian)(dian)(dian)感(gan)(gan)線(xian)(xian)圈來暫時(shi)儲存(cun),這樣(yang)他(ta)的(de)(de)損耗(hao)就(jiu)(jiu)小,功率(lv)也就(jiu)(jiu)高(gao),對(dui)散(san)熱(re)的(de)(de)要(yao)求低(di),但它(ta)對(dui)變壓(ya)器(qi)(qi)和貯能電(dian)(dian)(dian)感(gan)(gan)也有了**的(de)(de)要(yao)求,要(yao)用低(di)損耗(hao)高(gao)磁(ci)導率(lv)的(de)(de)材料(liao)來做。它(ta)的(de)(de)變壓(ya)器(qi)(qi)便是一個字小。總功率(lv)在(zai)80%~98%,開(kai)關電(dian)(dian)(dian)源的(de)(de)功率(lv)高(gao)但體積小,但是和線(xian)(xian)性電(dian)(dian)(dian)源比他(ta)的(de)(de)紋(wen)波(bo),電(dian)(dian)(dian)壓(ya)電(dian)(dian)(dian)流(liu)調整率(lv)就(jiu)(jiu)有必定的(de)(de)折扣了。