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線性電源和開關電源的優缺點

2019/6/28 10:29:32??????點擊:
    都是(shi)直流電 按要(yao)求(qiu)不同使用(yong)不同 ,線性電源(yuan)最好(hao) 他(ta)輸出(chu)的是(shi)線性直流電,可以用(yong)在(zai)要(yao)求(qiu)高的場合,開關電源(yuan)次之(zhi),他(ta)是(shi)由很高的開關速度的變壓器和開關管,特點是(shi)重量小,容量大(da),輸出(chu)質量高,相控電原用(yong)在(zai)要(yao)求(qiu)不高,電流特大(da)的場合
    線性電(dian)(dian)源(yuan),開關電(dian)(dian)源(yuan)區別
    線性(xing)電源(yuan)的調整管工(gong)作在放大(da)(da)狀態,因而發熱量大(da)(da),效率低(35%左右),需(xu)(xu)要加(jia)體積龐(pang)大(da)(da)的散熱片,而且還需(xu)(xu)要同樣(yang)也是大(da)(da)體積的工(gong)頻(pin)變(bian)(bian)壓器(qi),當(dang)要制作多組電壓輸出時變(bian)(bian)壓器(qi)會更(geng)龐(pang)大(da)(da)。
    開(kai)關(guan)電(dian)源的(de)調(diao)整管(guan)工作(zuo)在(zai)飽和和截至狀態,因而發熱量小,效率高(75%以(yi)上(shang))而且省掉了(le)大(da)體(ti)積的(de)變壓器。但開(kai)關(guan)電(dian)源輸出(chu)的(de)直流(liu)上(shang)面會疊加較大(da)的(de)紋(wen)波(bo)(50mV at 5V output typical),在(zai)輸出(chu)端并(bing)接穩壓二極(ji)管(guan)可(ke)以(yi)改(gai)善(shan),另外由(you)于開(kai)關(guan)管(guan)工作(zuo)是會產生很大(da)的(de)尖峰脈沖干擾,也需(xu)要在(zai)電(dian)路中(zhong)串(chuan)連磁珠加以(yi)改(gai)善(shan)。相(xiang)對(dui)而言線性電(dian)源就沒有以(yi)上(shang)缺陷,它的(de)紋(wen)波(bo)可(ke)以(yi)做(zuo)的(de)很小(5mV以(yi)下)。
    對于電(dian)(dian)(dian)(dian)(dian)(dian)源效(xiao)率和安(an)裝體積(ji)有要求(qiu)(qiu)的地方(fang)用(yong)(yong)開關(guan)電(dian)(dian)(dian)(dian)(dian)(dian)源為(wei)佳,對于電(dian)(dian)(dian)(dian)(dian)(dian)磁干擾和電(dian)(dian)(dian)(dian)(dian)(dian)源純凈性有要求(qiu)(qiu)的地方(fang)(例如電(dian)(dian)(dian)(dian)(dian)(dian)容(rong)漏電(dian)(dian)(dian)(dian)(dian)(dian)檢(jian)測)多選用(yong)(yong)線性電(dian)(dian)(dian)(dian)(dian)(dian)源。另外當電(dian)(dian)(dian)(dian)(dian)(dian)路中需要作隔(ge)(ge)離(li)的時(shi)候現在多數用(yong)(yong)DC-DC來做對隔(ge)(ge)離(li)部分供電(dian)(dian)(dian)(dian)(dian)(dian)(DC-DC從其(qi)工作原理上(shang)來說就是開關(guan)電(dian)(dian)(dian)(dian)(dian)(dian)源)。還(huan)有,開關(guan)電(dian)(dian)(dian)(dian)(dian)(dian)源中用(yong)(yong)到(dao)的高(gao)頻變壓器可能(neng)繞制起來比較麻(ma)煩
    開(kai)(kai)關(guan)電(dian)(dian)源(yuan)(yuan)和線(xian)性(xing)電(dian)(dian)源(yuan)(yuan)在(zai)內(nei)(nei)部結(jie)構(gou)上是(shi)(shi)(shi)完全不(bu)一樣的(de),開(kai)(kai)關(guan)電(dian)(dian)源(yuan)(yuan)顧名思義有開(kai)(kai)關(guan)動(dong)作(zuo),它利用變占空比或變頻的(de)方(fang)法實現(xian)不(bu)同的(de)電(dian)(dian)壓,實現(xian)較為復雜(za),最(zui)大的(de)優(you)點(dian)(dian)是(shi)(shi)(shi)高效率(lv),一般在(zai)90%以(yi)上,缺點(dian)(dian)是(shi)(shi)(shi)文(wen)波(bo)和開(kai)(kai)關(guan)噪(zao)聲較大,適用于對文(wen)波(bo)和噪(zao)聲要求不(bu)高的(de)場(chang)合;而線(xian)性(xing)電(dian)(dian)源(yuan)(yuan)沒有開(kai)(kai)關(guan)動(dong)作(zuo),屬于連續(xu)模擬控制,內(nei)(nei)部結(jie)構(gou)相對簡單,芯片面積(ji)也較小,成本較低,優(you)點(dian)(dian)是(shi)(shi)(shi)成本低,文(wen)波(bo)噪(zao)聲小,最(zui)大的(de)缺點(dian)(dian)是(shi)(shi)(shi)效率(lv)低。它們(men)各有有缺點(dian)(dian)在(zai)應用上互補共存!
    一、線(xian)性電源的原(yuan)理:
    線性電(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)主要(yao)包括工(gong)(gong)頻變壓(ya)(ya)(ya)器(qi)、輸出整流(liu)(liu)(liu)(liu)(liu)濾波(bo)(bo)器(qi)、控制(zhi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)路、保護電(dian)(dian)(dian)(dian)(dian)(dian)(dian)路等(deng)。 線性電(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)是(shi)先將交流(liu)(liu)(liu)(liu)(liu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)經(jing)過(guo)(guo)變壓(ya)(ya)(ya)器(qi)變壓(ya)(ya)(ya),再經(jing)過(guo)(guo)整流(liu)(liu)(liu)(liu)(liu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)路整流(liu)(liu)(liu)(liu)(liu)濾波(bo)(bo)得到未穩(wen)定(ding)的(de)直流(liu)(liu)(liu)(liu)(liu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya),要(yao)達到高精度的(de)直流(liu)(liu)(liu)(liu)(liu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya),必須經(jing)過(guo)(guo)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)反饋調整輸出電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya),這種電(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)技術很成熟,可以達到很高的(de)穩(wen)定(ding)度,波(bo)(bo)紋也很小,而(er)且沒有(you)開(kai)關電(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)具有(you)的(de)干擾與噪音。但是(shi)它的(de)缺點是(shi)需(xu)要(yao)龐(pang)大而(er)笨重(zhong)的(de)變壓(ya)(ya)(ya)器(qi),所(suo)需(xu)的(de)濾波(bo)(bo)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)容的(de)體積(ji)和重(zhong)量(liang)也相(xiang)當大,而(er)且電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)反饋電(dian)(dian)(dian)(dian)(dian)(dian)(dian)路是(shi)工(gong)(gong)作在(zai)線性狀態,調整管(guan)上有(you)一定(ding)的(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)降(jiang),在(zai)輸出較大工(gong)(gong)作電(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)(liu)(liu)時,致(zhi)使調整管(guan)的(de)功耗太大,轉換效率低(di),還要(yao)安裝很大的(de)散(san)熱片。這種電(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)不適(shi)合計算機等(deng)設備(bei)的(de)需(xu)要(yao),將逐步被開(kai)關電(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)所(suo)取代。
    二、開(kai)關電源的(de)原理:
    開關電源主要包括輸入電網濾波器、輸入整流濾波器、逆變(bian)器、輸出整流濾波器、控(kong)制電路、保護電路。它們的功能是:
    1、輸入電網(wang)濾波器(qi):消(xiao)除(chu)來自(zi)電網(wang),如(ru)電動機的啟動、電器(qi)的開關、雷擊等產生的干擾,同時也防止開關電源產生的高頻噪聲向電網(wang)擴散。
    2、輸(shu)入整流濾波(bo)器:將電(dian)網輸(shu)入電(dian)壓進(jin)行整流濾波(bo),為變換器提供(gong)直(zhi)流電(dian)壓。
    3、逆變器:是開關(guan)電源的關(guan)鍵部分。它(ta)把直流(liu)電壓變換成高頻(pin)交流(liu)電壓,并且起(qi)到將(jiang)輸出(chu)部分與輸入(ru)電網隔離的作用。
    4、輸(shu)出整流(liu)濾(lv)波器:將變換器輸(shu)出的(de)高(gao)(gao)頻(pin)(pin)交流(liu)電壓整流(liu)濾(lv)波得(de)到需要(yao)的(de)直(zhi)流(liu)電壓,同時還防(fang)止高(gao)(gao)頻(pin)(pin)噪聲對(dui)負(fu)載的(de)干(gan)擾(rao)。
    5、控(kong)制(zhi)電路(lu):檢測輸(shu)出(chu)直流電壓(ya),并將(jiang)其(qi)與基準電壓(ya)比較(jiao),進行放(fang)大(da)。調制(zhi)振蕩(dang)器的脈沖寬(kuan)度,從而控(kong)制(zhi)變(bian)換器以保持輸(shu)出(chu)電壓(ya)的穩定。
    6、保(bao)(bao)護電(dian)(dian)路(lu):當開關電(dian)(dian)源發(fa)生過電(dian)(dian)壓(ya)、過電(dian)(dian)流短路(lu)時,保(bao)(bao)護電(dian)(dian)路(lu)使開關電(dian)(dian)源停止工(gong)作以保(bao)(bao)護負載和電(dian)(dian)源本身。
    開關電(dian)源是將交(jiao)流電(dian)先整流成直(zhi)流電(dian),在(zai)將直(zhi)流逆(ni)變(bian)成交(jiao)流電(dian),在(zai)整流輸(shu)出成所需(xu)要的直(zhi)流電(dian)壓(ya)。這樣開關電(dian)源省去下線性電(dian)源中(zhong)的變(bian)壓(ya)器,以及電(dian)壓(ya)反饋電(dian)路。而開關電(dian)源中(zhong)的逆(ni)變(bian)電(dian)路完全是數字調(diao)整,同樣能達到非(fei)常高的調(diao)整精度。
    開(kai)關(guan)電(dian)源的主要優點:
    體(ti)積(ji)(ji)小、重(zhong)量輕(qing)(體(ti)積(ji)(ji)和(he)重(zhong)量只(zhi)有(you)線性電源的(de)20~30%)、效率(lv)高(一(yi)般(ban)為60~70%,而線性電源只(zhi)有(you)30~40%)、自(zi)身抗干擾性強、輸出電壓(ya)范(fan)圍寬、模塊(kuai)化(hua)。
    開關(guan)電源的主(zhu)要缺點:
    由于逆變電路中(zhong)會產生高(gao)頻電壓(ya),對(dui)周(zhou)圍設(she)備有一定的干擾。需要良好的屏(ping)蔽及(ji)接地
    開關(guan)電(dian)源就是(shi)(shi)(shi)(shi)用通過電(dian)路(lu)控制開關(guan)管進(jin)行高(gao)速的(de)道通與(yu)截止.將直流(liu)(liu)電(dian)轉化為(wei)高(gao)頻率的(de)交(jiao)流(liu)(liu)電(dian)提供給變(bian)壓器(qi)進(jin)行變(bian)壓,從而產生所(suo)需要(yao)(yao)的(de)一(yi)組或多組電(dian)壓!轉華為(wei)高(gao)頻交(jiao)流(liu)(liu)電(dian)的(de)原因是(shi)(shi)(shi)(shi)高(gao)頻交(jiao)流(liu)(liu)在變(bian)壓器(qi)變(bian)壓電(dian)路(lu)中的(de)效率要(yao)(yao)比50Hz高(gao)很(hen)多.所(suo)以(yi)開關(guan)變(bian)壓器(qi)可以(yi)做的(de)很(hen)小,而且工作時不是(shi)(shi)(shi)(shi)很(hen)熱!!成本很(hen)低.如果不將50Hz變(bian)為(wei)高(gao)頻那開關(guan)電(dian)源就沒有(you)意(yi)義!!開關(guan)變(bian)壓器(qi)也不神秘.就是(shi)(shi)(shi)(shi)一(yi)個(ge)普通的(de)變(bian)壓器(qi)!這就是(shi)(shi)(shi)(shi)開關(guan)電(dian)源。
    開關電源,是通過(guo)電子技術(shu)實現的,主(zhu)要(yao)環節(jie):整流成直流電——逆(ni)變成所需電壓(ya)的交(jiao)流電(主(zhu)要(yao)來調整電壓(ya))——再(zai)經過(guo)整流成直流電壓(ya)輸出。
    開關電(dian)源(yuan)的(de)結構中由于中間沒有變壓器和散熱片(pian),因(yin)而體積非(fei)常(chang)小(xiao)。同時,開關電(dian)源(yuan)內部都是電(dian)子元件,效率(lv)高、發(fa)熱小(xiao)。雖然,具有電(dian)磁干擾等缺點,但現在的(de)屏(ping)蔽技(ji)術已經非(fei)常(chang)到位。
    開關電源大(da)體可以分為(wei)隔(ge)離(li)(li)和(he)非隔(ge)離(li)(li)兩種,隔(ge)離(li)(li)型(xing)的必定(ding)有開關變壓(ya)器,而非隔(ge)離(li)(li)的未(wei)必一定(ding)有。
    簡單地說,開關(guan)電源的工作原理是:
    1.交流(liu)電(dian)源輸入經整流(liu)濾(lv)波成直(zhi)流(liu);
    2.通過高頻PWM(脈(mo)沖寬度調制)信號控制開(kai)關(guan)管,將那個直流加到開(kai)關(guan)變壓器初級(ji)上;
    3.開(kai)關變壓器次級感應出高頻(pin)電(dian)壓,經整流濾波供給負(fu)載(zai);
    4.輸出(chu)部分(fen)通過一定(ding)的(de)電(dian)路反饋給控制(zhi)電(dian)路,控制(zhi)PWM占空比,以達到(dao)穩定(ding)輸出(chu)的(de)目的(de).
    交流電(dian)(dian)源輸(shu)入時一般(ban)要經過(guo)厄流圈一類的(de)(de)東西,過(guo)濾掉(diao)電(dian)(dian)網上(shang)的(de)(de)干(gan)擾(rao)(rao),同時也過(guo)濾掉(diao)電(dian)(dian)源對電(dian)(dian)網的(de)(de)干(gan)擾(rao)(rao);在功率相同時,開關(guan)頻率越(yue)高(gao),開關(guan)變(bian)壓器的(de)(de)體積就越(yue)小,但(dan)對開關(guan)管的(de)(de)要求就越(yue)高(gao);開關(guan)變(bian)壓器的(de)(de)次級可(ke)以有(you)多個繞(rao)組或(huo)一個繞(rao)組有(you)多個抽頭,以得到需要的(de)(de)輸(shu)出;一般(ban)還應該增加一些(xie)保護電(dian)(dian)路,比如空載、短路等保護,否則可(ke)能會燒毀(hui)開關(guan)電(dian)(dian)源。
    以上說的(de)就是開關電源的(de)大致工作原(yuan)理。
    其實(shi)現在已經有(you)了(le)集成度非常高的專用芯(xin)片,可以使(shi)外圍電路非常簡(jian)單,甚至做到免調試(shi)。
    例如TOP系列的開(kai)關(guan)電源芯片(或稱(cheng)模塊),只要配合一(yi)(yi)些(xie)阻容元件(jian),和一(yi)(yi)個開(kai)關(guan)變(bian)壓器,就可以做成一(yi)(yi)個基本的開(kai)關(guan)電源。
    開關電源&線性電源
    開(kai)(kai)關(guan)電(dian)源(yuan)的主要(yao)工作原理(li)就是上(shang)橋(qiao)(qiao)和下(xia)(xia)橋(qiao)(qiao)的Mos管輪流(liu)導通,首先電(dian)流(liu)通過(guo)上(shang)橋(qiao)(qiao)Mos管流(liu)入,利用(yong)線圈的存儲(chu)功(gong)能(neng),將電(dian)能(neng)集聚在線圈中,最后(hou)關(guan)閉上(shang)橋(qiao)(qiao)Mos管,打(da)開(kai)(kai)下(xia)(xia)橋(qiao)(qiao)的Mos管,線圈和電(dian)容持續給外部供電(dian)。然后(hou)又關(guan)閉下(xia)(xia)橋(qiao)(qiao)Mos管,再打(da)開(kai)(kai)上(shang)橋(qiao)(qiao)讓電(dian)流(liu)進(jin)入,就這樣重復(fu)進(jin)行,因(yin)為要(yao)輪流(liu)開(kai)(kai)關(guan)Mos管,所以稱為開(kai)(kai)關(guan)電(dian)源(yuan)。
    而(er)線性電(dian)源(yuan)就不(bu)一(yi)樣(yang)了,由于沒有開關介入,使得(de)上(shang)水(shui)管(guan)一(yi)直在放(fang)水(shui),如果有多(duo)的(de)(de)(de),就會漏出來,這就是(shi)我(wo)們(men)經常看(kan)到的(de)(de)(de)某(mou)些線性電(dian)源(yuan)的(de)(de)(de)Mos管(guan)發(fa)熱(re)量(liang)很大,用不(bu)完(wan)的(de)(de)(de)電(dian)能(neng)(neng),全(quan)部轉(zhuan)換(huan)成(cheng)了熱(re)能(neng)(neng)。從(cong)這個角度來看(kan),線性電(dian)源(yuan)的(de)(de)(de)轉(zhuan)換(huan)效率就非常低了,而(er)且(qie)熱(re)量(liang)高的(de)(de)(de)時候(hou),元件的(de)(de)(de)壽命勢必要下降,影響最終的(de)(de)(de)使用效果 。
    開關電(dian)源和線性電(dian)源的區別主(zhu)要是(shi)他們的工作方式(shi)。
    線性(xing)電源功率器件工(gong)作在線性(xing)狀態,也就(jiu)是說他(ta)一用(yong)起來功率器件就(jiu)是一直在工(gong)作,所以(yi)也就(jiu)導致他(ta)的(de)(de)工(gong)作效率低(di),一般在50%~60%,還得說他(ta)是很好(hao)(hao)的(de)(de)線性(xing)電源。線性(xing)電源的(de)(de)工(gong)作方(fang)式,使他(ta)從高壓(ya)變低(di)壓(ya)必(bi)須有(you)將壓(ya)裝(zhuang)置,一般的(de)(de)都是變壓(ya)器,也有(you)別的(de)(de)像KX電源,再(zai)經(jing)過(guo)整流輸出直流電壓(ya)。這樣一來他(ta)的(de)(de)體積也就(jiu)很大(da)(da)(da),笨(ben)重,效率低(di)、發(fa)熱量也大(da)(da)(da)。他(ta)也有(you)他(ta)的(de)(de)優點:紋波小,調整率好(hao)(hao),對外干擾小。適合用(yong)與模(mo)擬電路(lu),各類放大(da)(da)(da)器等。
    開關(guan)(guan)電(dian)(dian)源(yuan)(yuan)。他的(de)(de)(de)功(gong)率(lv)器件工作在(zai)(zai)開關(guan)(guan)狀態,(一開一關(guan)(guan),一開一關(guan)(guan),頻率(lv)非常快,一般的(de)(de)(de)平(ping)板開關(guan)(guan)電(dian)(dian)源(yuan)(yuan)頻率(lv)在(zai)(zai)100~200KHz,模(mo)塊電(dian)(dian)源(yuan)(yuan)在(zai)(zai)300~500KHZ).這(zhe)樣(yang)他的(de)(de)(de)損耗(hao)就小,效(xiao)率(lv)也就高(gao),對變壓(ya)器也有了要(yao)(yao)求,要(yao)(yao)用高(gao)磁導率(lv)的(de)(de)(de)材料來做.有點墨跡了,他的(de)(de)(de)變壓(ya)器就是(shi)一個(ge)字小.效(xiao)率(lv)80%~90%吧.據說美國最(zui)好(hao)的(de)(de)(de)VICOR模(mo)塊高(gao)達99%.開關(guan)(guan)電(dian)(dian)源(yuan)(yuan)的(de)(de)(de)效(xiao)率(lv)高(gao)體(ti)積小,但是(shi)和線性電(dian)(dian)源(yuan)(yuan)比他的(de)(de)(de)紋波,電(dian)(dian)壓(ya)電(dian)(dian)流調(diao)整(zheng)率(lv)就有折扣了 。
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