為實現市電(dian)(dian)供(gong)電(dian)(dian)與逆變器供(gong)電(dian)(dian)之(zhi)間的自動(dong)切換(huan)，而(er)EPS電(dian)(dian)源(yuan)(yuan)按(an)國(guo)家標準(zhun)需是后備式的，因此(ci)自動(dong)切換(huan)裝(zhuang)置是EPS電(dian)(dian)源(yuan)(yuan)中必不可少的部(bu)件，也是影響EPS電(dian)(dian)源(yuan)(yuan)在可靠性方面(mian)的關鍵部(bu)件之(zhi)一，因此(ci)濟南啟(qi)創電(dian)(dian)氣(qi)有限公司專門就自動(dong)切換(huan)裝(zhuang)置進行(xing)了下面(mian)的分析解釋。
??????根(gen)據EPS電(dian)(dian)源的輸(shu)出容量和負載(zai)要(yao)(yao)(yao)求(qiu)(qiu)不(bu)同(tong)，自動切(qie)換(huan)(huan)裝置可(ke)采用(yong)功率繼電(dian)(dian)器、交流接觸器、互(hu)投(tou)開關、固態開關（晶閘管(guan)）等(deng)構成(cheng)。對EPS的切(qie)換(huan)(huan)時(shi)間(jian)(jian)要(yao)(yao)(yao)求(qiu)(qiu)具有多樣性，比如，一般(ban)消(xiao)防應(ying)急照明(ming)要(yao)(yao)(yao)求(qiu)(qiu)切(qie)換(huan)(huan)時(shi)間(jian)(jian)小(xiao)于5s，但是高危險區域使用(yong)的消(xiao)防應(ying)急照明(ming)要(yao)(yao)(yao)求(qiu)(qiu)切(qie)換(huan)(huan)時(shi)間(jian)(jian)小(xiao)于0.25s，為高壓氣(qi)體放電(dian)(dian)燈(deng)供電(dian)(dian)時(shi)不(bu)熄(xi)輝，則要(yao)(yao)(yao)求(qiu)(qiu)切(qie)換(huan)(huan)時(shi)間(jian)(jian)為數(shu)毫(hao)秒(miao)量級，而為風(feng)機、泵類、卷(juan)簾(lian)門、電(dian)(dian)梯等(deng)負載(zai)供電(dian)(dian)時(shi)，根(gen)據應(ying)用(yong)要(yao)(yao)(yao)求(qiu)(qiu)不(bu)同(tong)，切(qie)換(huan)(huan)時(shi)間(jian)(jian)也會在數(shu)毫(hao)秒(miao)等(deng)。
??????EPS電(dian)源與UPS電(dian)源不同之處在(zai)(zai)于(yu)多數應用(yong)場合對切換時(shi)間沒有很(hen)苛刻要(yao)求(qiu)，在(zai)(zai)切換時(shi)間的(de)(de)(de)要(yao)求(qiu)也并不是越短(duan)越好，在(zai)(zai)能滿(man)足應用(yong)需求(qiu)的(de)(de)(de)大前(qian)提下(xia)，適(shi)當慢一點(dian)切換可(ke)(ke)在(zai)(zai)其他方(fang)面(mian)獲益(yi)，比如可(ke)(ke)以降低損耗(hao)，減小暫態沖擊，提高可(ke)(ke)靠性(xing)等等方(fang)面(mian)，避免負載(zai)可(ke)(ke)能由(you)于(yu)瞬間的(de)(de)(de)斷電(dian)而(er)導致工(gong)作失常(chang)等。市電(dian)正常(chang)時(shi)EPS電(dian)源的(de)(de)(de)逆變器(qi)基本(ben)上都處于(yu)備用(yong)狀態，而(er)且有冷備份(fen)與熱備份(fen)兩種工(gong)作方(fang)式。
在冷備份(fen)(fen)時，逆變器(qi)只是控制部分(fen)處(chu)于(yu)工作(zuo)狀(zhuang)態，功率部分(fen)處(chu)于(yu)加(jia)電待機狀(zhuang)態，但不起(qi)動(dong)；熱備份(fen)(fen)時，整個逆變器(qi)處(chu)于(yu)正常運轉狀(zhuang)態，但不承擔負載。當逆變器(qi)熱備份(fen)(fen)時，最短(duan)切換時間基本(ben)決(jue)定于(yu)所用切換裝置的動(dong)作(zuo)時間；
而當(dang)逆(ni)(ni)(ni)變(bian)器(qi)(qi)(qi)冷備(bei)份時(shi)，最短切換時(shi)間還要受逆(ni)(ni)(ni)變(bian)器(qi)(qi)(qi)其(qi)動(dong)時(shi)間的(de)制約。特別是容量(liang)較(jiao)大(da)(da)(da)的(de)EPS電源，如果(guo)起動(dong)過(guo)快，逆(ni)(ni)(ni)變(bian)變(bian)壓器(qi)(qi)(qi)和(he)低通濾波器(qi)(qi)(qi)會產(chan)生很(hen)大(da)(da)(da)的(de)暫態沖擊，甚至可(ke)能損壞IGBT功率器(qi)(qi)(qi)件，因此(ci)逆(ni)(ni)(ni)變(bian)器(qi)(qi)(qi)一般都具備(bei)軟起動(dong)特性(xing)，且功率越大(da)(da)(da)，起動(dong)越慢，大(da)(da)(da)容量(liang)EPS逆(ni)(ni)(ni)變(bian)器(qi)(qi)(qi)的(de)起動(dong)時(shi)間可(ke)達(da)數秒之久(jiu)。如果(guo)要求更(geng)快的(de)切換時(shi)間，則只能采取熱備(bei)份工(gong)作(zuo)方式，此(ci)時(shi)EPS的(de)待機損耗(hao)自然要增加許多，整機效率會較(jiao)低。
至于(yu)使用哪種切(qie)(qie)(qie)換(huan)(huan)裝(zhuang)置，這主(zhu)要(yao)是依據對(dui)(dui)切(qie)(qie)(qie)換(huan)(huan)時(shi)間(jian)的要(yao)求而(er)定。如要(yao)求毫秒級的切(qie)(qie)(qie)換(huan)(huan)時(shi)間(jian)，那么就(jiu)只能采(cai)用固態開(kai)關(guan)(guan)（晶閘(zha)管(guan)）切(qie)(qie)(qie)換(huan)(huan)，且逆(ni)變(bian)器(qi)要(yao)處(chu)于(yu)熱備(bei)狀態。與同容量(liang)的機(ji)械(xie)切(qie)(qie)(qie)換(huan)(huan)開(kai)關(guan)(guan)相比，固態開(kai)關(guan)(guan)（晶閘(zha)管(guan)）切(qie)(qie)(qie)換(huan)(huan)的造價要(yao)高得多(duo)，通態損耗(hao)也會相對(dui)(dui)比較(jiao)多(duo)。在(zai)對(dui)(dui)切(qie)(qie)(qie)換(huan)(huan)時(shi)間(jian)沒有苛刻要(yao)求的應用場合，一般采(cai)用機(ji)械(xie)切(qie)(qie)(qie)換(huan)(huan)開(kai)關(guan)(guan)進行切(qie)(qie)(qie)換(huan)(huan)，容量(liang)較(jiao)小的EPS電源一般采(cai)用功(gong)率繼電器(qi)，功(gong)率較(jiao)大(da)的EPS通常采(cai)用互(hu)鎖的交流接觸器(qi)或自(zi)動互(hu)投開(kai)關(guan)(guan)。與交流接觸器(qi)相比，自(zi)動互(hu)投開(kai)關(guan)(guan)動作較(jiao)慢，但由于(yu)互(hu)投開(kai)關(guan)(guan)具(ju)有機(ji)械(xie)自(zi)保持特性(xing)，對(dui)(dui)于(yu)不頻繁的切(qie)(qie)(qie)換(huan)(huan)而(er)言(yan)，在(zai)長期運行的可靠性(xing)方面更具(ju)優勢。
用(yong)固(gu)態開關(guan)（晶閘管）實現市(shi)電(dian)(dian)(dian)與(yu)逆變器(qi)輸(shu)出(chu)之(zhi)間的(de)(de)快(kuai)速(su)切(qie)換(huan)(huan)技術雖在UPS電(dian)(dian)(dian)源中應用(yong)多年，但也有(you)所不同(tong)，UPS用(yong)功(gong)率(lv)繼電(dian)(dian)(dian)器(qi)（或接(jie)(jie)觸器(qi)）與(yu)固(gu)態開關(guan)（晶閘管）組合成(cheng)一個(ge)旁路（BYPASS）切(qie)換(huan)(huan)裝置的(de)(de)，固(gu)態開關(guan)（晶閘管）主要是做瞬間過載旁路（BYPASS）切(qie)換(huan)(huan)，靠(kao)它瞬間使(shi)逆變器(qi)與(yu)電(dian)(dian)(dian)網有(you)個(ge)短暫的(de)(de)并(bing)聯(lian)運行，從而獲得瞬間無切(qie)換(huan)(huan)時間的(de)(de)供電(dian)(dian)(dian)（彌補了(le)功(gong)率(lv)繼電(dian)(dian)(dian)器(qi)或接(jie)(jie)觸器(qi)的(de)(de)渡越時間）。
關鍵是(shi)要實現逆(ni)變(bian)(bian)器(qi)的(de)(de)(de)鎖相運(yun)行(xing)(xing)和對市電(dian)(dian)(dian)即時(shi)(shi)(shi)電(dian)(dian)(dian)壓的(de)(de)(de)快速檢(jian)測(ce)與跟蹤(zong)。它并不(bu)(bu)是(shi)真(zhen)真(zhen)的(de)(de)(de)斷(duan)(duan)電(dian)(dian)(dian)切(qie)(qie)(qie)換，因(yin)這(zhe)種(zhong)方式(shi)均(jun)為(wei)“在線(xian)式(shi)”UPS所用(yong)，真(zhen)真(zhen)的(de)(de)(de)斷(duan)(duan)電(dian)(dian)(dian)切(qie)(qie)(qie)換工(gong)作時(shi)(shi)(shi)固態(tai)開關（晶(jing)閘管）是(shi)不(bu)(bu)參(can)于(yu)(yu)工(gong)作的(de)(de)(de)。當其用(yong)于(yu)(yu)EPS電(dian)(dian)(dian)源(yuan)時(shi)(shi)(shi)才(cai)真(zhen)正是(shi)固態(tai)開關（晶(jing)閘管）的(de)(de)(de)參(can)與斷(duan)(duan)電(dian)(dian)(dian)切(qie)(qie)(qie)換，EPS電(dian)(dian)(dian)源(yuan)均(jun)為(wei)后備式(shi)是(shi)不(bu)(bu)設旁路接觸器(qi)的(de)(de)(de)。就是(shi)處于(yu)(yu)在市電(dian)(dian)(dian)正常、逆(ni)變(bian)(bian)器(qi)也正常運(yun)轉的(de)(de)(de)情(qing)況下，即使(shi)是(shi)進(jin)行(xing)(xing)不(bu)(bu)間(jian)(jian)斷(duan)(duan)的(de)(de)(de)切(qie)(qie)(qie)換，在技術(shu)上(shang)也是(shi)可(ke)以做到的(de)(de)(de)，但實際情(qing)況是(shi)，切(qie)(qie)(qie)換需要在市電(dian)(dian)(dian)突(tu)然發生中斷(duan)(duan)或故(gu)障(zhang)(zhang)時(shi)(shi)(shi)進(jin)行(xing)(xing)，因(yin)市電(dian)(dian)(dian)中斷(duan)(duan)或故(gu)障(zhang)(zhang)的(de)(de)(de)發生時(shi)(shi)(shi)刻是(shi)隨機的(de)(de)(de)和非預知的(de)(de)(de)，檢(jian)測(ce)確認市電(dian)(dian)(dian)故(gu)障(zhang)(zhang)需要時(shi)(shi)(shi)間(jian)(jian)，此時(shi)(shi)(shi)的(de)(de)(de)切(qie)(qie)(qie)換時(shi)(shi)(shi)間(jian)(jian)不(bu)(bu)可(ke)能小于(yu)(yu)檢(jian)測(ce)、確認市電(dian)(dian)(dian)故(gu)障(zhang)(zhang)需要的(de)(de)(de)時(shi)(shi)(shi)間(jian)(jian)。
為(wei)(wei)防止各(ge)種(zhong)電(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)干擾導致誤動(dong)作，檢(jian)測時(shi)間(jian)不(bu)能(neng)(neng)太短。實(shi)踐證明，當(dang)檢(jian)測時(shi)間(jian)小于(yu)2ms時(shi)，檢(jian)測可(ke)靠(kao)性會明顯下(xia)降。因此小于(yu)2ms的(de)(de)(de)(de)切(qie)(qie)換時(shi)間(jian)是(shi)不(bu)可(ke)取(qu)。在(zai)(zai)EPS電(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)所應(ying)用(yong)各(ge)類負(fu)載里，對(dui)切(qie)(qie)換時(shi)間(jian)要(yao)(yao)求最苛刻的(de)(de)(de)(de)應(ying)當(dang)是(shi)高(gao)(gao)壓(ya)氣體放(fang)電(dian)(dian)(dian)(dian)(dian)燈。雖(sui)然(ran)這種(zhong)燈具不(bu)允許(xu)用(yong)于(yu)消防應(ying)急照(zhao)明，但由于(yu)其具有(you)(you)高(gao)(gao)強度、高(gao)(gao)效率的(de)(de)(de)(de)性能(neng)(neng)特(te)點(dian)，在(zai)(zai)很多大型場(chang)館中(zhong)都(dou)有(you)(you)應(ying)用(yong)。但有(you)(you)這么一(yi)個問題，那就(jiu)(jiu)是(shi)這種(zhong)燈具一(yi)旦熄(xi)輝(hui)，需(xu)要(yao)(yao)冷卻(que)后方(fang)能(neng)(neng)重(zhong)新啟動(dong)，為(wei)(wei)保證照(zhao)明不(bu)發(fa)生中(zhong)斷(duan)，EPS電(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)必須具備快速切(qie)(qie)換能(neng)(neng)力。根(gen)據對(dui)多種(zhong)高(gao)(gao)壓(ya)氣體放(fang)電(dian)(dian)(dian)(dian)(dian)燈產品(pin)的(de)(de)(de)(de)測試，如果(guo)不(bu)采取(qu)適(shi)當(dang)的(de)(de)(de)(de)續流措施，5ms的(de)(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)力中(zhong)斷(duan)就(jiu)(jiu)有(you)(you)可(ke)能(neng)(neng)導致熄(xi)輝(hui)，個別產品(pin)甚至3ms電(dian)(dian)(dian)(dian)(dian)力中(zhong)斷(duan)就(jiu)(jiu)會熄(xi)輝(hui)。而對(dui)于(yu)某些電(dian)(dian)(dian)(dian)(dian)梯(ti)類負(fu)載，毫秒級的(de)(de)(de)(de)切(qie)(qie)換顯然(ran)是(shi)沒有(you)(you)必要(yao)(yao)的(de)(de)(de)(de)，但切(qie)(qie)換時(shi)的(de)(de)(de)(de)瞬間(jian)中(zhong)斷(duan)電(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)同(tong)樣有(you)(you)可(ke)能(neng)(neng)導致電(dian)(dian)(dian)(dian)(dian)梯(ti)控制系(xi)統(tong)進(jin)入保護狀態。此種(zhong)情況需(xu)要(yao)(yao)通過EPS電(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)控制系(xi)統(tong)的(de)(de)(de)(de)延(yan)時(shi)適(shi)當(dang)增加切(qie)(qie)換時(shi)間(jian)，才能(neng)(neng)保證電(dian)(dian)(dian)(dian)(dian)梯(ti)在(zai)(zai)應(ying)急供電(dian)(dian)(dian)(dian)(dian)后繼(ji)續正常運行(xing)。在(zai)(zai)有(you)(you)些應(ying)用(yong)場(chang)合，為(wei)(wei)了實(shi)現零切(qie)(qie)換，要(yao)(yao)求將(jiang)EPS設(she)計成在(zai)(zai)線運行(xing)方(fang)式(shi)，那么這時(shi)EPS電(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)實(shi)際就(jiu)(jiu)已經(jing)變(bian)成一(yi)臺專用(yong)的(de)(de)(de)(de)UPS，逆變(bian)器(qi)是(shi)長帶負(fu)荷工作的(de)(de)(de)(de)。
想(xiang)了解更多(duo)濟(ji)南啟(qi)創(chuang)電氣有限公司(si)(udbd.cn)相關(guan)知識，可瀏覽濟(ji)南啟(qi)創(chuang)電氣有限公司(si)的官方網站(zhan)，我們會經常(chang)推送一(yi)些您感(gan)興趣的內容，比如EPS電源(yuan)、UPS電源(yuan)等相關(guan)資訊信息。
