電(dian)(dian)(dian)(dian)(dian)池(chi)(chi)的(de)(de)(de)質量(liang)問題固然(ran)對(dui)UPS至關重(zhong)要，但(dan)充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)器的(de)(de)(de)充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)質量(liang)在(zai)(zai)很大程度(du)上影響(xiang)著電(dian)(dian)(dian)(dian)(dian)池(chi)(chi)的(de)(de)(de)質量(liang)，其(qi)原因在(zai)(zai)前面已經提及(ji)。尤其(qi)是(shi)(shi)電(dian)(dian)(dian)(dian)(dian)池(chi)(chi)充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)的(de)(de)(de)精度(du)一定要保(bao)證(zheng)，因為(wei)浮充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)的(de)(de)(de)過高或(huo)過低都(dou)會影響(xiang)電(dian)(dian)(dian)(dian)(dian)池(chi)(chi)的(de)(de)(de)壽命(ming)(ming)，圖1表示的(de)(de)(de)是(shi)(shi)MSE電(dian)(dian)(dian)(dian)(dian)池(chi)(chi)的(de)(de)(de)充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)與壽命(ming)(ming)的(de)(de)(de)關系，該(gai)實驗是(shi)(shi)在(zai)(zai)40oC的(de)(de)(de)條件下加(jia)速進行的(de)(de)(de)。由(you)此曲線可以看(kan)出，在(zai)(zai)這(zhe)里的(de)(de)(de)浮充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)推薦值是(shi)(shi)2.25V/cell，高于這(zhe)個值或(huo)低于這(zhe)個值都(dou)會縮短(duan)電(dian)(dian)(dian)(dian)(dian)池(chi)(chi)的(de)(de)(de)壽命(ming)(ming)。比(bi)如浮充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)是(shi)(shi)2.225V/cell時(shi)，壽命(ming)(ming)將縮短(duan)5%，而浮充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)上升到2.4V/cell時(shi)，壽命(ming)(ming)就縮短(duan)了40%。由(you)此可見，維持精確的(de)(de)(de)浮充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)值是(shi)(shi)如何重(zhong)要。但(dan)為(wei)了使電(dian)(dian)(dian)(dian)(dian)池(chi)(chi)長(chang)期(qi)使用(yong)后還能保(bao)證(zheng)各(ge)電(dian)(dian)(dian)(dian)(dian)池(chi)(chi)電(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)的(de)(de)(de)平衡(heng)(heng)，采用(yong)的(de)(de)(de)措施是(shi)(shi)均衡(heng)(heng)充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)，而均衡(heng)(heng)充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)的(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)也大都(dou)是(shi)(shi)2.4V/cell，這(zhe)就和(he)上面的(de)(de)(de)曲線發生了矛(mao)盾，實際上事情就是(shi)(shi)這(zhe)樣，有得就有失，所以電(dian)(dian)(dian)(dian)(dian)池(chi)(chi)在(zai)(zai)均衡(heng)(heng)充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)時(shi)一定要控制好時(shi)間(jian)，以盡量(liang)延長(chang)電(dian)(dian)(dian)(dian)(dian)池(chi)(chi)的(de)(de)(de)服(fu)務壽命(ming)(ming)。

　　圖1 MSE電池(chi)的充電電壓與壽命(ming)的關系（40oC加(jia)速(su)實驗）

1.恒壓充電

　　所謂恒壓(ya)充(chong)(chong)電(dian)(dian)(dian)(dian)就(jiu)(jiu)是用一穩壓(ya)源給電(dian)(dian)(dian)(dian)池(chi)(chi)充(chong)(chong)電(dian)(dian)(dian)(dian)，這(zhe)種方(fang)法簡單(dan)易行(xing)，也能(neng)夠保(bao)證電(dian)(dian)(dian)(dian)池(chi)(chi)的(de)精確浮充(chong)(chong)電(dian)(dian)(dian)(dian)壓(ya)。但若在電(dian)(dian)(dian)(dian)池(chi)(chi)深度放電(dian)(dian)(dian)(dian)后充(chong)(chong)電(dian)(dian)(dian)(dian)時，由(you)于電(dian)(dian)(dian)(dian)池(chi)(chi)的(de)內阻相對而(er)言仍然很低(di)，就(jiu)(jiu)會(hui)(hui)有很大的(de)充(chong)(chong)電(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)流使化學(xue)反(fan)應(ying)劇烈地(di)進(jin)(jin)行(xing)，從而(er)產生大量的(de)氣(qi)(qi)體，由(you)于還原反(fan)應(ying)來不及(ji)進(jin)(jin)行(xing)，使殼(ke)內氣(qi)(qi)壓(ya)迅速(su)增加(jia)，沖開(kai)排氣(qi)(qi)閥將(jiang)氣(qi)(qi)體逸出(chu)，加(jia)速(su)了電(dian)(dian)(dian)(dian)解(jie)液的(de)干(gan)涸，縮短了電(dian)(dian)(dian)(dian)池(chi)(chi)的(de)壽命；若排氣(qi)(qi)閥因故(gu)障而(er)無法打開(kai)，就(jiu)(jiu)會(hui)(hui)使電(dian)(dian)(dian)(dian)池(chi)(chi)的(de)外殼(ke)鼓脹或破裂。隨著(zhu)電(dian)(dian)(dian)(dian)池(chi)(chi)電(dian)(dian)(dian)(dian)壓(ya)的(de)升高，充(chong)(chong)電(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)流逐(zhu)漸(jian)減小(xiao)，其(qi)減小(xiao)的(de)規律是：

 　　                                             （1）

式中(zhong)   ICH――電(dian)池(chi)的充電(dian)電(dian)流，A；

       E――充電(dian)器的輸出電(dian)壓，V；

       UGB――電池電壓，V；

       RGB――電池的內阻，Ω。

　　上(shang)式中有三個(ge)變量ICH、UGB、RGB，充(chong)電電流ICH隨著充(chong)電過(guo)程(cheng)的(de)進(jin)行而減(jian)小，電池(chi)(chi)電壓UGB隨著充(chong)電過(guo)程(cheng)的(de)進(jin)行而升(sheng)高，而電池(chi)(chi)內(nei)阻RGB隨著充(chong)電過(guo)程(cheng)的(de)進(jin)行而減(jian)小。這就決定了充(chong)電過(guo)程(cheng)的(de)非線性。尤其是(shi)在(zai)接(jie)近(jin)浮充(chong)電壓值(zhi)時，使(shi)充(chong)電變的(de)非常緩(huan)慢，從(cong)理論上(shang)講，充(chong)電到(dao)額定浮充(chong)值(zhi)的(de)時間是(shi)無窮大。

　　這種充電方式在早(zao)期的小容量UPS中(zhong)曾一度使用過，因出現(xian)了好多故障，目前(qian)一般不用了。{{分頁}}

2.恒流充電

　　恒流(liu)(liu)充(chong)(chong)(chong)(chong)(chong)電(dian)(dian)的(de)(de)(de)好處(chu)在(zai)于：一(yi)方(fang)(fang)面可以限(xian)制充(chong)(chong)(chong)(chong)(chong)電(dian)(dian)電(dian)(dian)流(liu)(liu)，避(bi)免(mian)了由(you)于上述的(de)(de)(de)劇烈反(fan)(fan)應而導(dao)(dao)致的(de)(de)(de)副作用(yong)；另一(yi)方(fang)(fang)面，可使充(chong)(chong)(chong)(chong)(chong)電(dian)(dian)直(zhi)線進(jin)行，加(jia)快了充(chong)(chong)(chong)(chong)(chong)電(dian)(dian)的(de)(de)(de)速度，也(ye)可避(bi)免(mian)接(jie)近浮(fu)充(chong)(chong)(chong)(chong)(chong)值(zhi)時(shi)的(de)(de)(de)過(guo)于緩慢(man)的(de)(de)(de)過(guo)程(cheng)(cheng)。這種方(fang)(fang)法(fa)也(ye)有不足之處(chu)，因為隨著充(chong)(chong)(chong)(chong)(chong)電(dian)(dian)過(guo)程(cheng)(cheng)的(de)(de)(de)進(jin)行，未經反(fan)(fan)應的(de)(de)(de)物質會(hui)(hui)越來(lai)越少，如果仍用(yong)充(chong)(chong)(chong)(chong)(chong)電(dian)(dian)初期的(de)(de)(de)電(dian)(dian)流(liu)(liu)注入，由(you)于反(fan)(fan)應物質的(de)(de)(de)缺(que)乏就會(hui)(hui)用(yong)水的(de)(de)(de)電(dian)(dian)解(jie)來(lai)填補，這又會(hui)(hui)導(dao)(dao)致水的(de)(de)(de)電(dian)(dian)離物氫和(he)氧的(de)(de)(de)快速蒸發(fa)，從而也(ye)縮短了電(dian)(dian)池(chi)(chi)的(de)(de)(de)服(fu)務壽(shou)命。因此(ci)(ci)也(ye)有的(de)(de)(de)提(ti)出在(zai)電(dian)(dian)池(chi)(chi)浮(fu)充(chong)(chong)(chong)(chong)(chong)電(dian)(dian)到“一(yi)定(ding)值(zhi)”時(shi)將充(chong)(chong)(chong)(chong)(chong)電(dian)(dian)電(dian)(dian)流(liu)(liu)減(jian)半(ban)。就是這個(ge)“一(yi)定(ding)值(zhi)”也(ye)很(hen)難掌握(wo)，尤其是接(jie)近額(e)定(ding)浮(fu)充(chong)(chong)(chong)(chong)(chong)電(dian)(dian)壓值(zhi)時(shi)，如果仍用(yong)這個(ge)即使是減(jian)了半(ban)的(de)(de)(de)電(dian)(dian)流(liu)(liu)強行灌入，也(ye)會(hui)(hui)加(jia)快電(dian)(dian)解(jie)水的(de)(de)(de)進(jin)程(cheng)(cheng)，縮短電(dian)(dian)池(chi)(chi)的(de)(de)(de)壽(shou)命。因此(ci)(ci)這個(ge)界(jie)限(xian)也(ye)難于劃分和(he)掌握(wo)。此(ci)(ci)種方(fang)(fang)法(fa)有的(de)(de)(de)在(zai)均衡充(chong)(chong)(chong)(chong)(chong)電(dian)(dian)中使用(yong)。

3.恒流恒壓充電

　　鑒于(yu)上述兩種充(chong)(chong)(chong)(chong)(chong)(chong)電(dian)方式(shi)的優點和不(bu)足，于(yu)是就推出了將二(er)者優點集合與一(yi)體的所謂恒(heng)(heng)流(liu)恒(heng)(heng)壓充(chong)(chong)(chong)(chong)(chong)(chong)電(dian)方式(shi)，實際(ji)上是限(xian)(xian)流(liu)恒(heng)(heng)壓充(chong)(chong)(chong)(chong)(chong)(chong)電(dian)方式(shi)。在充(chong)(chong)(chong)(chong)(chong)(chong)電(dian)初(chu)期由(you)于(yu)電(dian)流(liu)有可(ke)能(neng)(neng)非(fei)常(chang)大，所以這(zhe)時的充(chong)(chong)(chong)(chong)(chong)(chong)電(dian)電(dian)路將該(gai)電(dian)流(liu)限(xian)(xian)制(zhi)在一(yi)個規定值(zhi)，使(shi)之(zhi)能(neng)(neng)最(zui)大限(xian)(xian)度(du)地保(bao)證既能(neng)(neng)快速充(chong)(chong)(chong)(chong)(chong)(chong)電(dian)，又能(neng)(neng)保(bao)證充(chong)(chong)(chong)(chong)(chong)(chong)電(dian)過程的安(an)全。這(zhe)一(yi)段的充(chong)(chong)(chong)(chong)(chong)(chong)電(dian)幾乎(hu)是線性的，隨著(zhu)充(chong)(chong)(chong)(chong)(chong)(chong)電(dian)過程的進行(xing)，大約充(chong)(chong)(chong)(chong)(chong)(chong)電(dian)至(zhi)80%～90%電(dian)池容量時，充(chong)(chong)(chong)(chong)(chong)(chong)電(dian)電(dian)流(liu)開(kai)始(shi)小于(yu)限(xian)(xian)流(liu)值(zhi)，其電(dian)流(liu)的變化開(kai)始(shi)遵從(cong)式(shi)(1)。目前(qian)UPS中的充(chong)(chong)(chong)(chong)(chong)(chong)電(dian)大都(dou)采(cai)用這(zhe)種方式(shi)。

4.充電電路

　　(1)概述  UPS中電(dian)(dian)(dian)(dian)(dian)池(chi)的(de)充(chong)電(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)路不外乎兩種：降(jiang)壓充(chong)電(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)路和升(sheng)壓充(chong)電(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)路。在一(yi)些小容(rong)(rong)量(liang)UPS中，由于電(dian)(dian)(dian)(dian)(dian)池(chi)組(zu)電(dian)(dian)(dian)(dian)(dian)壓比較(jiao)低(di)，故(gu)多(duo)(duo)用降(jiang)壓電(dian)(dian)(dian)(dian)(dian)路，比如Smart、Matrix和Symmetra等系列UPS中，電(dian)(dian)(dian)(dian)(dian)池(chi)組(zu)額定電(dian)(dian)(dian)(dian)(dian)壓最高(gao)(gao)也(ye)就是120V，浮(fu)充(chong)電(dian)(dian)(dian)(dian)(dian)壓也(ye)小于140V，由單相(xiang)220V交流(liu)(liu)電(dian)(dian)(dian)(dian)(dian)壓足(zu)可(ke)以(yi)得到此值；為了提高(gao)(gao)充(chong)電(dian)(dian)(dian)(dian)(dian)器(qi)(qi)的(de)效(xiao)率(lv)和降(jiang)低(di)功(gong)耗，充(chong)電(dian)(dian)(dian)(dian)(dian)器(qi)(qi)多(duo)(duo)采用稱為Buck電(dian)(dian)(dian)(dian)(dian)路的(de)高(gao)(gao)頻PWM方案，這(zhe)在前面已有介(jie)紹。在中大容(rong)(rong)量(liang)的(de)UPS系統中，輸入多(duo)(duo)是三相(xiang)電(dian)(dian)(dian)(dian)(dian)壓，又由于輸入整流(liu)(liu)器(qi)(qi)采用了相(xiang)控的(de)晶閘管方案，本身的(de)輸出電(dian)(dian)(dian)(dian)(dian)壓穩(wen)定度(du)已達到了蓄電(dian)(dian)(dian)(dian)(dian)池(chi)的(de)要求，故(gu)電(dian)(dian)(dian)(dian)(dian)池(chi)的(de)充(chong)電(dian)(dian)(dian)(dian)(dian)功(gong)能統一(yi)由整流(liu)(liu)器(qi)(qi)負擔(dan)，這(zhe)也(ye)是一(yi)個(ge)降(jiang)壓充(chong)電(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)路。

　　只有一部分小容量(liang)UPS采(cai)用(yong)(yong)了高壓(ya)電(dian)池組(zu)，比如單相220V輸(shu)入的Imel 7.5kVA UPS就采(cai)用(yong)(yong)了384V的電(dian)池電(dian)壓(ya)，遠遠超(chao)過了220V交流電(dian)壓(ya)幅值310V，因(yin)此不提(ti)高電(dian)壓(ya)就無法滿足電(dian)池組(zu)的充(chong)電(dian)要求(qiu)。所以(yi)機器中就采(cai)用(yong)(yong)了稱為(wei)Boost的升壓(ya)PWM電(dian)路(lu)。

　　一般UPS電(dian)(dian)(dian)源的(de)(de)后備(bei)時(shi)間大都在10min左右，充(chong)電(dian)(dian)(dian)器的(de)(de)設計也與(yu)此對(dui)應(ying)。如遇有長延時(shi)的(de)(de)要(yao)求(qiu)，雖然增(zeng)加(jia)(jia)了電(dian)(dian)(dian)池(chi)可以滿足(zu)其放電(dian)(dian)(dian)的(de)(de)能力，但充(chong)電(dian)(dian)(dian)的(de)(de)速度就(jiu)遠達不到目(mu)的(de)(de)了。比如一般UPS內(nei)(nei)含10min電(dian)(dian)(dian)池(chi)時(shi)，放電(dian)(dian)(dian)后重新充(chong)電(dian)(dian)(dian)的(de)(de)時(shi)間為10～12h。當有的(de)(de)用戶提(ti)出了8h要(yao)求(qiu)時(shi)，電(dian)(dian)(dian)池(chi)容量增(zeng)加(jia)(jia)到原來(lai)的(de)(de)48倍！若(ruo)充(chong)足(zu)如此大的(de)(de)電(dian)(dian)(dian)池(chi)顯然不能靠UPS的(de)(de)內(nei)(nei)部充(chong)電(dian)(dian)(dian)器了。于是(shi)就(jiu)提(ti)出了外加(jia)(jia)充(chong)電(dian)(dian)(dian)器的(de)(de)要(yao)求(qiu)。

　　(2)UPS外(wai)(wai)加(jia)充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)器(qi)的(de)(de)(de)配置(zhi)原則(ze)  UPS外(wai)(wai)加(jia)充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)器(qi)的(de)(de)(de)配置(zhi)原則(ze)首先是(shi)(shi)要和(he)UPS隔(ge)(ge)離，其次才(cai)是(shi)(shi)電(dian)(dian)(dian)(dian)磁兼容(rong)指標要和(he)UPS相適應(ying)。以往(wang)市場上的(de)(de)(de)商品充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)器(qi)雖然(ran)也考(kao)慮了(le)隔(ge)(ge)離問(wen)題，并且(qie)也采取了(le)措(cuo)施(shi)，但(dan)(dan)由(you)于措(cuo)施(shi)不(bu)利(li)，也不(bu)乏(fa)導(dao)致(zhi)UPS故障的(de)(de)(de)例子(zi)。圖(tu)(tu)2就(jiu)是(shi)(shi)一(yi)般(ban)外(wai)(wai)加(jia)充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)器(qi)隔(ge)(ge)離措(cuo)施(shi)圖(tu)(tu)，實(shi)際上所謂的(de)(de)(de)隔(ge)(ge)離措(cuo)施(shi)就(jiu)是(shi)(shi)一(yi)只二(er)(er)極管(guan)。GB1是(shi)(shi)UPS內部(bu)電(dian)(dian)(dian)(dian)池(chi)組(zu)，GB2是(shi)(shi)外(wai)(wai)加(jia)長延(yan)時(shi)電(dian)(dian)(dian)(dian)池(chi)組(zu)，而(er)往(wang)往(wang)由(you)于外(wai)(wai)加(jia)電(dian)(dian)(dian)(dian)池(chi)組(zu)的(de)(de)(de)容(rong)量遠大于內部(bu)電(dian)(dian)(dian)(dian)池(chi)組(zu)，一(yi)般(ban)將(jiang)GB1省掉了(le)，無論是(shi)(shi)省掉還是(shi)(shi)不(bu)省掉，都有(you)一(yi)個(ge)不(bu)變的(de)(de)(de)事實(shi)，即UPS內部(bu)充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)器(qi)和(he)外(wai)(wai)加(jia)充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)器(qi)的(de)(de)(de)直(zhi)(zhi)接并聯。為了(le)隔(ge)(ge)離相互間的(de)(de)(de)影響，多數(shu)外(wai)(wai)加(jia)充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)器(qi)多在其輸(shu)出(chu)正端串(chuan)聯了(le)一(yi)只正向(xiang)二(er)(er)極管(guan)D。這(zhe)樣做的(de)(de)(de)結果是(shi)(shi)隔(ge)(ge)離了(le)UPS對(dui)充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)器(qi)的(de)(de)(de)影響，保(bao)證了(le)它(ta)不(bu)受其干(gan)擾，但(dan)(dan)沒有(you)消除充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)器(qi)對(dui)UPS的(de)(de)(de)干(gan)擾。而(er)且(qie)最關鍵的(de)(de)(de)就(jiu)是(shi)(shi)怕外(wai)(wai)加(jia)充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)器(qi)對(dui)UPS的(de)(de)(de)干(gan)擾。當外(wai)(wai)加(jia)充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)器(qi)充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)壓(ya)因(yin)失控而(er)突然(ran)增(zeng)高時(shi)，它(ta)就(jiu)會通(tong)過二(er)(er)極管(guan)去干(gan)擾UPS，如果該外(wai)(wai)加(jia)充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)器(qi)的(de)(de)(de)輸(shu)出(chu)電(dian)(dian)(dian)(dian)壓(ya)是(shi)(shi)由(you)市電(dian)(dian)(dian)(dian)直(zhi)(zhi)接整(zheng)流(liu)后通(tong)過開(kai)關管(guan)斬(zhan)波(bo)(PWM)而(er)來，這(zhe)就(jiu)將(jiang)市電(dian)(dian)(dian)(dian)直(zhi)(zhi)接接入(ru)UPS直(zhi)(zhi)流(liu)電(dian)(dian)(dian)(dian)路，就(jiu)會導(dao)致(zhi)故障。當然(ran)，此類故障不(bu)會多見(jian)，但(dan)(dan)導(dao)致(zhi)UPS冒煙的(de)(de)(de)例子(zi)已經有(you)過。這(zhe)種明顯存在隱(yin)患的(de)(de)(de)電(dian)(dian)(dian)(dian)路一(yi)定要謹用。

　　圖2 一般外加充電器隔離措施(shi)圖

　　為了完全隔(ge)離相互間的(de)(de)干擾，圖3的(de)(de)外加充(chong)電(dian)器(qi)完全隔(ge)離方案是(shi)可取的(de)(de)，并在長期的(de)(de)實踐運(yun)行中得(de)到了證明，既安全又可靠。{{分頁}}

　　圖3 外加(jia)充電器完全隔(ge)離方案原理圖

　　①外加(jia)充電器完全隔離方案(an)設(she)計思想：

　　a.充分保證UPS電路的(de)完整(zheng)性，即該(gai)方(fang)案不(bu)動UPS的(de)一點一線，不(bu)從(cong)(cong)UPS機(ji)內引出任何附(fu)加的(de)信號線。按照UPS正常的(de)要求(qiu)，只從(cong)(cong)UPS的(de)輸出接(jie)線端子(zi)做正常連接(jie)。

　　b.在(zai)外加充電(dian)器(qi)與UPS電(dian)池(chi)之間加接一個(ge)(ge)簡單的(de)三端雙向(xiang)互投(tou)機(ji)構，如圖3所示，用一個(ge)(ge)中(zhong)間繼電(dian)器(qi)J（或接觸器(qi)甚至雙投(tou)手動開關），將(jiang)該機(ji)構的(de)中(zhong)間臂3接外加電(dian)池(chi)組GB2的(de)正極，繼電(dian)器(qi)線(xian)包J跨接在(zai)UPS市電(dian)輸入線(xian)上。

　　c.當市電(dian)(dian)(dian)正常供電(dian)(dian)(dian)時(shi)(shi)(shi)，由(you)于繼(ji)電(dian)(dian)(dian)器線包J被激勵(li)而將(jiang)觸點臂3由(you)常閉觸點1打向2，此(ci)時(shi)(shi)(shi)正好(hao)是外(wai)加(jia)充電(dian)(dian)(dian)器正常輸出充電(dian)(dian)(dian)時(shi)(shi)(shi)期，GB2被正常充電(dian)(dian)(dian)。可(ke)以看出，此(ci)時(shi)(shi)(shi)UPS和外(wai)加(jia)充電(dian)(dian)(dian)器是完全隔離的，并且UPS的充電(dian)(dian)(dian)器僅僅給自己的電(dian)(dian)(dian)池(chi)GB1充電(dian)(dian)(dian)，保證了其原有的一切充電(dian)(dian)(dian)功能。

　　d.當市電(dian)(dian)斷電(dian)(dian)時，繼電(dian)(dian)器線包J被釋放(fang)，中間臂3由2回到1，將外加電(dian)(dian)池(chi)組GB2并聯在(zai)GB1上，形(xing)成了純電(dian)(dian)池(chi)組的并聯，也就達到了大(da)容量(liang)電(dian)(dian)池(chi)長延(yan)時放(fang)電(dian)(dian)的目的。

　　e.市電(dian)恢(hui)復(fu)時(shi)，繼(ji)電(dian)器又回到“3-2”狀態。這(zhe)里(li)可能有(you)(you)這(zhe)樣一個問(wen)題：市電(dian)恢(hui)復(fu)時(shi)，由于繼(ji)電(dian)器動(dong)作(zuo)存在(zai)惰性，有(you)(you)可能外加電(dian)池組GB2不能及時(shi)斷開，將會造成UPS內部充(chong)(chong)電(dian)器同時(shi)為(wei)(wei)兩組電(dian)池充(chong)(chong)電(dian)的(de)局(ju)面，會不會因充(chong)(chong)電(dian)電(dian)流(liu)太大而(er)導(dao)致(zhi)故障呢？回答是(shi)否定的(de)。因為(wei)(wei)所有(you)(you)在(zai)線式(shi)(shi)UPS的(de)充(chong)(chong)電(dian)器都(dou)是(shi)限流(liu)溫壓式(shi)(shi)的(de)，所以不會過流(liu)。

　　上面(mian)只是(shi)給出了一個原理(li)方案，實際結構還要復雜(za)一些。不過，用這(zhe)個原理(li)進行隔離已經足夠(gou)了。

　　關(guan)于外加(jia)充電(dian)(dian)器(qi)的(de)電(dian)(dian)磁兼容(rong)問(wen)題也(ye)不(bu)可(ke)忽視，由于現代(dai)UPS的(de)用戶大都(dou)集(ji)通(tong)信(xin)和(he)大量的(de)數據傳輸為(wei)(wei)一(yi)體，尤其(qi)牽(qian)涉到(dao)無(wu)(wu)(wu)線通(tong)信(xin)，就(jiu)更要(yao)求(qiu)供電(dian)(dian)系(xi)統(tong)(tong)不(bu)能對用電(dian)(dian)系(xi)統(tong)(tong)有任何干擾(rao)(rao)。因此(ci)，一(yi)般UPS系(xi)統(tong)(tong)都(dou)要(yao)通(tong)過一(yi)定的(de)電(dian)(dian)磁兼容(rong)標準，如EN50091-2等。然而一(yi)般市面上的(de)外加(jia)充電(dian)(dian)器(qi)很(hen)少注意(yi)到(dao)這些(xie)問(wen)題，恰恰PWM開關(guan)電(dian)(dian)源(yuan)就(jiu)是(shi)(shi)無(wu)(wu)(wu)線通(tong)信(xin)的(de)敏感干擾(rao)(rao)源(yuan)，因此(ci)不(bu)得不(bu)向其(qi)提出相(xiang)應的(de)要(yao)求(qiu)。有時為(wei)(wei)了安全起(qi)見，采用原理上的(de)無(wu)(wu)(wu)干擾(rao)(rao)電(dian)(dian)路(lu)是(shi)(shi)必要(yao)的(de)。圖(tu)4表(biao)示的(de)就(jiu)是(shi)(shi)這樣一(yi)種(zhong)無(wu)(wu)(wu)干擾(rao)(rao)充電(dian)(dian)器(qi)電(dian)(dian)路(lu)原理圖(tu)，這是(shi)(shi)一(yi)個典型(xing)的(de)具有限(xian)流穩壓(ya)功能的(de)充電(dian)(dian)器(qi)。

　　圖4 無干(gan)擾充電器電路原理圖{{分頁(ye)}}

　　②無干擾充電器電路特點(dian)：

　　a.電(dian)路結構(gou)簡單、成(cheng)(cheng)熟、可(ke)靠。主回路只(zhi)有(you)電(dian)容器(qi)和普通整流(liu)器(qi)，這種(zhong)傳統(tong)器(qi)件的(de)制造歷(li)(li)史很(hen)長，已達到很(hen)高的(de)可(ke)靠性指標；輔助(zhu)充電(dian)器(qi)也是歷(li)(li)史很(hen)長的(de)、性能指標非常好的(de)傳統(tong)電(dian)路，輸出電(dian)壓精度很(hen)容易做(zuo)到1%，輸出電(dian)壓紋(wen)波做(zuo)到<5mV則輕而(er)易舉；測量與控制電(dian)路都是由傳統(tong)的(de)比較器(qi)、運算放大器(qi)之類的(de)組件構(gou)成(cheng)(cheng)，可(ke)靠性當然更無(wu)問題；執行器(qi)件是一只(zhi)繼(ji)電(dian)器(qi)，一般觸點(dian)的(de)動(dong)作次數都在106次以上。

　　b.電(dian)路(lu)工作原理(li)簡單、實用。充(chong)電(dian)器(qi)的兩(liang)個主要功能(neng)就(jiu)是(shi)限流充(chong)電(dian)和穩壓(ya)浮(fu)充(chong)。該電(dian)路(lu)中的限流是(shi)靠一只電(dian)容器(qi)來完成(cheng)的，既無電(dian)流傳感器(qi)又(you)無反饋控(kong)制機構，僅僅靠電(dian)容本身的電(dian)壓(ya)自(zi)調整就(jiu)實現了限流功能(neng)；大(da)(da)(da)電(dian)流充(chong)電(dian)和高(gao)精度(du)浮(fu)充(chong)溫壓(ya)分別進行，就(jiu)大(da)(da)(da)大(da)(da)(da)簡化(hua)了電(dian)路(lu)，指標也(ye)容易做得好(hao)；用繼電(dian)器(qi)做主充(chong)電(dian)電(dian)路(lu)和輔助充(chong)電(dian)器(qi)（線性穩壓(ya)器(qi)）的切(qie)換機構而(er)不考(kao)慮(lv)0切(qie)換，這正是(shi)利用了電(dian)路(lu)對該指標不加考(kao)慮(lv)的特點。

　　c.整個電路的(de)(de)(de)工(gong)(gong)作狀態都(dou)(dou)是線性(xing)的(de)(de)(de)，無產(chan)生高頻干擾的(de)(de)(de)機構(gou)和(he)過(guo)程。主回路的(de)(de)(de)電容器和(he)普(pu)通整流(liu)器都(dou)(dou)自然地工(gong)(gong)作于50Hz，線性(xing)穩壓器從小信號到大信號都(dou)(dou)是典型的(de)(de)(de)線性(xing)工(gong)(gong)作狀態，測量與控制電路也僅(jin)僅(jin)是對直流(liu)電平的(de)(de)(de)線性(xing)轉換(huan)。

　　因(yin)此，整個電路(lu)從原理上就杜(du)絕了高頻干擾的發生。不(bu)過這(zhe)種電路(lu)比同容量(liang)的PWM充電器(qi)(qi)體積要大一些。因(yin)此，在那些對(dui)干擾指標要求(qiu)不(bu)太嚴格的地(di)方，PWM充電器(qi)(qi)還是得到了廣泛的應用。

　　(3)雙電池組充電器：

　　①升壓（Boost）充(chong)電(dian)(dian)電(dian)(dian)路。單電(dian)(dian)子器件的(de)發(fa)展促進了(le)UPS技術的(de)發(fa)展，近(jin)年來高頻(pin)機UPS的(de)出現(xian)，使該類產品(pin)的(de)逆變(bian)器輸出省去了(le)笨重的(de)隔離變(bian)壓器，同時將電(dian)(dian)池(chi)由一組(zu)(zu)增(zeng)加到(dao)兩組(zu)(zu)，但容量不變(bian)，比如原(yuan)來用一組(zu)(zu)電(dian)(dian)池(chi)時是100Ah，而現(xian)在變(bian)成了(le)兩組(zu)(zu)50Ah。如圖(tu)5所示(shi)的(de)GB1和GB2。兩組(zu)(zu)電(dian)(dian)池(chi)串(chuan)聯連接，每組(zu)(zu)電(dian)(dian)池(chi)標(biao)(biao)稱電(dian)(dian)壓一般為(wei)384V，兩組(zu)(zu)串(chuan)聯總電(dian)(dian)壓為(wei)768V，若按照2.25V/單元的(de)標(biao)(biao)準充(chong)電(dian)(dian)，兩組(zu)(zu)電(dian)(dian)池(chi)的(de)浮充(chong)電(dian)(dian)壓就(jiu)需：