作為UPS關鍵部件的充電器與UPS的(de)許多指標密切相關。文(wen)章提出了UPS充(chong)電(dian)器的(de)設計要(yao)求，將UPS按功(gong)率(lv)大小(xiao)劃分，分別為(wei)它們(men)選擇了合適(shi)的(de)充(chong)電(dian)器拓撲(pu)，并分析了工作原理，指出了存在的(de)不足。

　　1 在線(xian)式(shi)UPS的組成(cheng)

　　隨(sui)著電(dian)(dian)(dian)(dian)(dian)子技術的(de)(de)飛(fei)速發(fa)展，各(ge)種各(ge)樣的(de)(de)電(dian)(dian)(dian)(dian)(dian)器(qi)設(she)備越來(lai)越多，而這(zhe)其中的(de)(de)大部分(fen)都是非(fei)線性負(fu)載(zai)，即它們從電(dian)(dian)(dian)(dian)(dian)網(wang)汲取的(de)(de)電(dian)(dian)(dian)(dian)(dian)流波形(xing)(xing)與電(dian)(dian)(dian)(dian)(dian)壓波形(xing)(xing)不(bu)一樣。這(zhe)無疑(yi)給電(dian)(dian)(dian)(dian)(dian)網(wang)帶來(lai)了大量的(de)(de)諧波以及(ji)其他的(de)(de)公(gong)害(hai)，使供電(dian)(dian)(dian)(dian)(dian)的(de)(de)質量變(bian)得較差。另一方面，一些重(zhong)要的(de)(de)用電(dian)(dian)(dian)(dian)(dian)部門(如(ru)機場(chang)、醫(yi)院、銀(yin)行)和一些重(zhong)要的(de)(de)用電(dian)(dian)(dian)(dian)(dian)設(she)備(如(ru)計算(suan)機、通信(xin)設(she)備)對供電(dian)(dian)(dian)(dian)(dian)質量的(de)(de)要求(qiu)(qiu)越來(lai)越高，不(bu)僅要求(qiu)(qiu)不(bu)停電(dian)(dian)(dian)(dian)(dian)，還要求(qiu)(qiu)電(dian)(dian)(dian)(dian)(dian)壓、頻率、波形(xing)(xing)質量良好，避(bi)免受到電(dian)(dian)(dian)(dian)(dian)網(wang)的(de)(de)干擾，具(ju)備一個凈(jing)化的(de)(de)電(dian)(dian)(dian)(dian)(dian)源環境。這(zhe)就使負(fu)載(zai)與電(dian)(dian)(dian)(dian)(dian)網(wang)供電(dian)(dian)(dian)(dian)(dian)質量之間(jian)的(de)(de)矛盾日益加劇(ju)。為(wei)解(jie)決這(zhe)一矛盾，UPS供電(dian)(dian)(dian)(dian)(dian)系統迅猛發(fa)展并(bing)普及(ji)起來(lai)。

　　隨著計算機、各(ge)種辦公設備、精密(mi)電(dian)(dian)(dian)(dian)(dian)子(zi)儀器的普及，UPS得(de)(de)到(dao)(dao)了廣泛(fan)的應(ying)用。現在應(ying)用較多(duo)的是在線式UPS，當(dang)市電(dian)(dian)(dian)(dian)(dian)正常(chang)時，電(dian)(dian)(dian)(dian)(dian)網電(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)一(yi)路(lu)經過(guo)整流模(mo)塊AC/DC、逆(ni)變模(mo)塊DC/AC，得(de)(de)到(dao)(dao)所需的正弦電(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)或(huo)(huo)準(zhun)方波電(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)供給(gei)負(fu)載(zai)，另(ling)一(yi)路(lu)通(tong)過(guo)充(chong)電(dian)(dian)(dian)(dian)(dian)模(mo)塊給(gei)電(dian)(dian)(dian)(dian)(dian)池(chi)充(chong)電(dian)(dian)(dian)(dian)(dian);市電(dian)(dian)(dian)(dian)(dian)異常(chang)時，電(dian)(dian)(dian)(dian)(dian)池(chi)通(tong)過(guo)DC/DC模(mo)塊、DC/AC模(mo)塊，輸出(chu)正弦電(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)或(huo)(huo)準(zhun)方波電(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)，給(gei)負(fu)載(zai)供電(dian)(dian)(dian)(dian)(dian);如(ru)果UPS異常(chang)，電(dian)(dian)(dian)(dian)(dian)網直(zhi)接(jie)通(tong)過(guo)旁路(lu)給(gei)負(fu)載(zai)供電(dian)(dian)(dian)(dian)(dian)。

　　2 UPS充電(dian)器的設計要(yao)求

　　UPS的市電輸入電壓范圍較寬，以輸出220V的UPS為例，輸入電壓為110-270V,充電器從市電取得這個范圍的輸入電壓，輸出還要達到一定的功率。充電器接入UPS后，會加大輸入電流的諧波失真，THDI升高，對THDI要求較高的UPS，有必要再充電器中加入功率因數校正環節，使輸入電流失真變小，輸入市電有高壓脈沖和浪涌，脈沖持續幾毫秒，高達七八百伏，浪涌是微妙級但高達4000V，他們會給充電器帶來瞬間高達幾百安培的電流沖擊，這對充電器是很大的考驗。中功率ULPS的電池節數不固定，從幾節到幾十節可變，充電器輸出電壓從幾十伏到幾百伏可變，輸出電壓如此寬泛，在設定的每個輸出電壓處，要求對輸入電壓和輸出負載的變化都有良好的響應，輸出電流(充電電流)紋波也要比較小，這樣輸出端不再需要耐高壓和高紋波電流的濾波電容。單端反激拓撲有隔離變壓器和輸出整流二極管，降低了效率，因此它難以應用于中大功率的充電器。輸出(chu)功(gong)率也(ye)(ye)是充(chong)電器設計需(xu)要考慮的，當然(ran)功(gong)率也(ye)(ye)很重要。作為UPS重要部件之(zhi)一(yi)的充(chong)電器，不(bu)得不(bu)考慮成本。歸納一(yi)下(xia)有如下(xia)設計要求：

　　(1) 要求輸入(ru)電壓寬泛;

　　(2) 充電器的THDI值小，且能承受一(yi)定市電脈(mo)沖和(he)浪涌(yong);

　　(3) 寬范(fan)圍可(ke)調節(jie)的輸出(chu)電(dian)壓，輸出(chu)電(dian)流波紋(wen)較小;

　　(4) 對(dui)輸入(ru)電壓和輸出負載有良好(hao)響(xiang)應(ying);

　　(5) 達(da)到設計的功(gong)率要求;

　　(6) 效率(lv)較高;

　　(7) 成本較低。

　　3 小功率UPS充電器拓撲的選擇

　　以某公司的1～3kVA功率等(deng)級的UPS為(wei)例，一般選擇(ze)單端反(fan)(fan)擊拓撲結構作為(wei)充電(dian)器(qi)(qi)，變壓(ya)器(qi)(qi)原副邊同名端相反(fan)(fan)，輸(shu)入從市電(dian)直(zhi)接獲取，經過整流濾(lv)波器(qi)(qi)后得到正弦半波電(dian)壓(ya)，再(zai)變換為(wei)所需的輸(shu)出電(dian)壓(ya)，如果按照不連續(xu)模(mo)式設計，變壓(ya)器(qi)(qi)原邊電(dian)感值較小且輸(shu)出端無電(dian)抗元件(jian)，控制系統對(dui)輸(shu)入電(dian)壓(ya)和輸(shu)出負(fu)載的響應要很快。

　　當VT1導通時，以(yi)輸入電(dian)(dian)(dian)壓(ya)正(zheng)半周(zhou)為(wei)(wei)(wei)例，輸入電(dian)(dian)(dian)流由L端(duan)經VD2、變壓(ya)器VR1原(yuan)(yuan)邊(bian)(bian)(bian)(bian)VT1、R1和(he)VD4回到N端(duan)，TR原(yuan)(yuan)邊(bian)(bian)(bian)(bian)產(chan)生(sheng)上(shang)正(zheng)下(xia)負(fu)(fu)(fu)的電(dian)(dian)(dian)壓(ya)，原(yuan)(yuan)邊(bian)(bian)(bian)(bian)電(dian)(dian)(dian)壓(ya)為(wei)(wei)(wei)Ui(Ui為(wei)(wei)(wei)市電(dian)(dian)(dian)整流后(hou)的半波電(dian)(dian)(dian)壓(ya))，副邊(bian)(bian)(bian)(bian)極(ji)性相應產(chan)生(sheng)下(xia)正(zheng)上(shang)負(fu)(fu)(fu)的電(dian)(dian)(dian)壓(ya)，二極(ji)管(guan)VD5承受反向電(dian)(dian)(dian)壓(ya)而截(jie)(jie)止(zhi)，VD5承受電(dian)(dian)(dian)壓(ya)為(wei)(wei)(wei)(Ns/Np)Ui+UB;VT1截(jie)(jie)止(zhi)時，為(wei)(wei)(wei)使磁芯工(gong)作(zuo)點順利返回，變壓(ya)器原(yuan)(yuan)邊(bian)(bian)(bian)(bian)產(chan)生(sheng)下(xia)負(fu)(fu)(fu)上(shang)正(zheng)電(dian)(dian)(dian)壓(ya)，則副邊(bian)(bian)(bian)(bian)電(dian)(dian)(dian)壓(ya)為(wei)(wei)(wei)上(shang)正(zheng)下(xia)負(fu)(fu)(fu)，副邊(bian)(bian)(bian)(bian)電(dian)(dian)(dian)流通過VD5向電(dian)(dian)(dian)池充電(dian)(dian)(dian)。原(yuan)(yuan)邊(bian)(bian)(bian)(bian)相應電(dian)(dian)(dian)壓(ya)為(wei)(wei)(wei)下(xia)正(zheng)上(shang)負(fu)(fu)(fu)，U1=-(Np/Ns)UB，則VT1承受電(dian)(dian)(dian)壓(ya)為(wei)(wei)(wei)(Np/Ns)UB+U1。根據原(yuan)(yuan)邊(bian)(bian)(bian)(bian)線圈的伏秒平衡。

　　但(dan)是，變壓器(qi)帶來磁(ci)滯損耗(hao)和繞線損耗(hao)，另外輸(shu)(shu)出(chu)電(dian)(dian)流波紋較大(da)，整體效率不高，VT1導通時輸(shu)(shu)出(chu)靠濾(lv)波電(dian)(dian)容(rong)(rong)C1維持，要用大(da)容(rong)(rong)量的濾(lv)波電(dian)(dian)容(rong)(rong)。

　　小功率(lv)UPS的(de)(de)充(chong)電器根(gen)據充(chong)電電流的(de)(de)打消設(she)計成(cheng)模組和充(chong)電板，為滿足UPS緊湊(cou)化的(de)(de)要求，降低成(cheng)本，把充(chong)電器設(she)計在功率(lv)板上將是一種選擇，輸入從母線(xian)電壓獲取。

　　DC/DC和充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)器(qi)(qi)利(li)用一個(ge)拓撲實現，即推挽(wan)正激(ji)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)，它在推挽(wan)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)的(de)基礎上變(bian)更(geng)了(le)(le)線阻N1、N2與(yu)開(kai)(kai)(kai)關(guan)(guan)(guan)管(guan)(guan)(guan)(guan)VT1、VT2的(de)為之，增加了(le)(le)一個(ge)儲(chu)能電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)容(rong)C1。為了(le)(le)形成(cheng)雙向電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)，在高(gao)壓(ya)側(ce)增加一個(ge)開(kai)(kai)(kai)關(guan)(guan)(guan)管(guan)(guan)(guan)(guan)VT4，低電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)側(ce)增加一個(ge)輔(fu)助充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)繞(rao)組和開(kai)(kai)(kai)關(guan)(guan)(guan)管(guan)(guan)(guan)(guan)VT3，形成(cheng)正激(ji)充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)，給電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)。電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)I1路(lu)徑如(ru)圖4所示。充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)時(shi)(shi)，VT3一直打(da)開(kai)(kai)(kai)，VT4進行(xing)PWM調制，繞(rao)組N5電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)大于(yu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)，給電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian);對于(yu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池模式(shi)下的(de)推挽(wan)正激(ji)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)，以VT1管(guan)(guan)(guan)(guan)和N1支(zhi)路(lu)為例，當(dang)VT1管(guan)(guan)(guan)(guan)開(kai)(kai)(kai)通(tong)(tong)時(shi)(shi)，電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)通(tong)(tong)過(guo)N1、VT1，在繞(rao)組N4感應出(chu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)給電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)容(rong)C2充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian);VT1關(guan)(guan)(guan)閉瞬間，電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)通(tong)(tong)過(guo)N1、C1、VT2體內二極管(guan)(guan)(guan)(guan)續流(liu)，當(dang)VT2開(kai)(kai)(kai)通(tong)(tong)時(shi)(shi)，C1電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)功(gong)過(guo)N1、VT2放電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)，在繞(rao)線N3感應出(chu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)給C2充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)，路(lu)徑見圖中I2。C1電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)容(rong)在VT1、VT2關(guan)(guan)(guan)斷時(shi)(shi)刻儲(chu)能，當(dang)相應對管(guan)(guan)(guan)(guan)開(kai)(kai)(kai)通(tong)(tong)時(shi)(shi)刻放電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)，由(you)此(ci)(ci)提高(gao)了(le)(le)效率，限制了(le)(le)開(kai)(kai)(kai)關(guan)(guan)(guan)管(guan)(guan)(guan)(guan)關(guan)(guan)(guan)斷時(shi)(shi)漏極電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)過(guo)大。這種拓撲尤其適合低電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)大電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)場(chang)合，因此(ci)(ci)可以減少電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池節數，降(jiang)低成(cheng)本。另(ling)外，提高(gao)了(le)(le)變(bian)壓(ya)器(qi)(qi)的(de)利(li)用率，充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)時(shi)(shi)充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)器(qi)(qi)輸出(chu)端沒(mei)有接輸出(chu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)感，充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)波紋過(guo)大。

　　4 中功率UPS充(chong)電(dian)器拓撲選擇

　　一般(ban)UPS的(de)電(dian)(dian)池(chi)節(jie)數是固定的(de)，像1kVA的(de)UPS配(pei)備2或(huo)3節(jie)電(dian)(dian)池(chi)，3kVA的(de)UPS配(pei)備6或(huo)8節(jie)，10kVA配(pei)備16或(huo)20節(jie)，中(zhong)功率UPS所配(pei)備的(de)電(dian)(dian)池(chi)節(jie)數較多，時間長(chang)了(le)，難免有電(dian)(dian)池(chi)損壞，要求相對(dui)應的(de)充(chong)電(dian)(dian)器電(dian)(dian)壓能做出調(diao)整(zheng)。某品牌10kVA UPS，電(dian)(dian)池(chi)在12-24節(jie)數范圍可調(diao)，對(dui)應充(chong)電(dian)(dian)器輸出電(dian)(dian)壓范圍為164-328V，單端反激拓撲輸出電(dian)(dian)壓幾乎不(bu)可能在此寬范圍可調(diao)，為此設(she)計了(le)BOOST-BUCK變換器。

　　前級采(cai)用BOOST結構，把(ba)市(shi)電(dian)(dian)升到400V，市(shi)電(dian)(dian)經(jing)整(zheng)流(liu)(liu)橋后(hou)得到直流(liu)(liu)脈動電(dian)(dian)壓(ya)，VT1導(dao)(dao)通時(shi)，L1上電(dian)(dian)流(liu)(liu)增加，并(bing)儲存能(neng)量(liang)，VD5承(cheng)受反向(xiang)電(dian)(dian)壓(ya)而(er)截(jie)(jie)止(zhi)，濾波電(dian)(dian)容C2給負載(zai)提供能(neng)量(liang);VT1截(jie)(jie)止(zhi)時(shi)，市(shi)電(dian)(dian)通過L1和VD5對(dui)電(dian)(dian)池(chi)充(chong)電(dian)(dian)，并(bing)給負載(zai)提供能(neng)量(liang)，輸(shu)(shu)入(ru)和輸(shu)(shu)出(chu)關(guan)系(xi)見(jian)式(shi)。后(hou)級采(cai)用BUCK結構，它把(ba)輸(shu)(shu)入(ru)端400V降到所需的充(chong)電(dian)(dian)電(dian)(dian)壓(ya)，VT2導(dao)(dao)通時(shi)，VD5承(cheng)受反向(xiang)電(dian)(dian)壓(ya)截(jie)(jie)止(zhi)，輸(shu)(shu)入(ru)經(jing)過L2給電(dian)(dian)容C2充(chong)電(dian)(dian)，并(bing)提供能(neng)量(liang)給負載(zai)，VT2截(jie)(jie)止(zhi)時(shi)，電(dian)(dian)感(gan)電(dian)(dian)流(liu)(liu)經(jing)過VD6續流(liu)(liu)，L2和C2共(gong)同負載(zai)提供能(neng)量(liang)，輸(shu)(shu)入(ru)輸(shu)(shu)出(chu)關(guan)系(xi)見(jian)式(shi)，聯(lian)立(li)式(shi)和式(shi)可得充(chong)電(dian)(dian)器輸(shu)(shu)入(ru)輸(shu)(shu)出(chu)關(guan)系(xi)，見(jian)式(shi)，D1不變，D2可變。

　　結束語

　　小功(gong)(gong)(gong)率(lv)(lv)UPS不(bu)要求(qiu)(qiu)寬(kuan)范圍的(de)輸(shu)出(chu)電(dian)壓，希(xi)望(wang)對輸(shu)入電(dian)壓和輸(shu)出(chu)負載有(you)良好相應，單端反激(ji)拓(tuo)(tuo)撲能滿足(zu)此(ci)要求(qiu)(qiu)，盡管其輸(shu)出(chu)功(gong)(gong)(gong)率(lv)(lv)和效率(lv)(lv)不(bu)高(gao);推挽正激(ji)拓(tuo)(tuo)撲同時實現(xian)了(le)充電(dian)器(qi)和DC/DC的(de)功(gong)(gong)(gong)能，減低(di)了(le)整機成本;中功(gong)(gong)(gong)率(lv)(lv)UPS則希(xi)望(wang)充電(dian)器(qi)輸(shu)出(chu)電(dian)壓可調，BOOST-BUCK和BOOST-半橋都(dou)是明智的(de)選擇;大功(gong)(gong)(gong)率(lv)(lv)UPS采用模(mo)塊化結構(gou)，對THDI和輸(shu)入功(gong)(gong)(gong)率(lv)(lv)因(yin)數等指標要求(qiu)(qiu)很(hen)高(gao)，輸(shu)入取自母(mu)線電(dian)壓的(de)BUCK變換器(qi)拓(tuo)(tuo)撲簡單實用，當然(ran)，BOOST一(yi)半橋在縮減模(mo)塊體積方面(mian)表現(xian)突出(chu)。