作為UPS關鍵部件的充電器與UPS的(de)許多指(zhi)標密切(qie)相關。文(wen)章提出(chu)了(le)UPS充(chong)電(dian)器的(de)設計要求，將UPS按功率大小劃分，分別為它們(men)選擇了(le)合(he)適的(de)充(chong)電(dian)器拓撲，并(bing)分析了(le)工作原理，指(zhi)出(chu)了(le)存在的(de)不足。

　　1 在線式UPS的(de)組成

　　隨著電(dian)(dian)(dian)子技術的(de)(de)(de)(de)(de)飛速發(fa)(fa)展，各種各樣的(de)(de)(de)(de)(de)電(dian)(dian)(dian)器設(she)備(bei)越(yue)(yue)來(lai)越(yue)(yue)多，而這(zhe)其(qi)中的(de)(de)(de)(de)(de)大部(bu)分(fen)都是非線性負載，即它們從電(dian)(dian)(dian)網(wang)汲取的(de)(de)(de)(de)(de)電(dian)(dian)(dian)流波(bo)(bo)形(xing)(xing)與(yu)電(dian)(dian)(dian)壓(ya)波(bo)(bo)形(xing)(xing)不(bu)一(yi)(yi)(yi)樣。這(zhe)無疑給電(dian)(dian)(dian)網(wang)帶來(lai)了大量(liang)(liang)(liang)的(de)(de)(de)(de)(de)諧波(bo)(bo)以(yi)及其(qi)他的(de)(de)(de)(de)(de)公害(hai)，使供(gong)電(dian)(dian)(dian)的(de)(de)(de)(de)(de)質(zhi)(zhi)量(liang)(liang)(liang)變得較差。另(ling)一(yi)(yi)(yi)方(fang)面，一(yi)(yi)(yi)些重要(yao)的(de)(de)(de)(de)(de)用(yong)(yong)電(dian)(dian)(dian)部(bu)門(如(ru)機(ji)場、醫院、銀行)和一(yi)(yi)(yi)些重要(yao)的(de)(de)(de)(de)(de)用(yong)(yong)電(dian)(dian)(dian)設(she)備(bei)(如(ru)計算機(ji)、通信設(she)備(bei))對供(gong)電(dian)(dian)(dian)質(zhi)(zhi)量(liang)(liang)(liang)的(de)(de)(de)(de)(de)要(yao)求越(yue)(yue)來(lai)越(yue)(yue)高，不(bu)僅要(yao)求不(bu)停(ting)電(dian)(dian)(dian)，還要(yao)求電(dian)(dian)(dian)壓(ya)、頻(pin)率、波(bo)(bo)形(xing)(xing)質(zhi)(zhi)量(liang)(liang)(liang)良(liang)好，避免受(shou)到電(dian)(dian)(dian)網(wang)的(de)(de)(de)(de)(de)干擾(rao)，具備(bei)一(yi)(yi)(yi)個凈(jing)化的(de)(de)(de)(de)(de)電(dian)(dian)(dian)源環境。這(zhe)就使負載與(yu)電(dian)(dian)(dian)網(wang)供(gong)電(dian)(dian)(dian)質(zhi)(zhi)量(liang)(liang)(liang)之間(jian)的(de)(de)(de)(de)(de)矛盾日益加劇(ju)。為解決這(zhe)一(yi)(yi)(yi)矛盾，UPS供(gong)電(dian)(dian)(dian)系統迅猛發(fa)(fa)展并普及起來(lai)。

　　隨著(zhu)計算機(ji)、各種辦(ban)公設(she)備、精密電(dian)(dian)(dian)(dian)(dian)(dian)子(zi)儀器的普及，UPS得到(dao)(dao)了(le)廣泛的應用(yong)(yong)。現(xian)在(zai)應用(yong)(yong)較多的是在(zai)線式UPS，當市(shi)電(dian)(dian)(dian)(dian)(dian)(dian)正(zheng)常時(shi)，電(dian)(dian)(dian)(dian)(dian)(dian)網(wang)電(dian)(dian)(dian)(dian)(dian)(dian)壓一(yi)路(lu)(lu)經過(guo)整流模(mo)(mo)塊AC/DC、逆變模(mo)(mo)塊DC/AC，得到(dao)(dao)所需的正(zheng)弦電(dian)(dian)(dian)(dian)(dian)(dian)壓或(huo)準方(fang)波(bo)(bo)電(dian)(dian)(dian)(dian)(dian)(dian)壓供(gong)給負(fu)載(zai)(zai)，另一(yi)路(lu)(lu)通(tong)過(guo)充電(dian)(dian)(dian)(dian)(dian)(dian)模(mo)(mo)塊給電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)充電(dian)(dian)(dian)(dian)(dian)(dian);市(shi)電(dian)(dian)(dian)(dian)(dian)(dian)異(yi)常時(shi)，電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)通(tong)過(guo)DC/DC模(mo)(mo)塊、DC/AC模(mo)(mo)塊，輸(shu)出正(zheng)弦電(dian)(dian)(dian)(dian)(dian)(dian)壓或(huo)準方(fang)波(bo)(bo)電(dian)(dian)(dian)(dian)(dian)(dian)壓，給負(fu)載(zai)(zai)供(gong)電(dian)(dian)(dian)(dian)(dian)(dian);如果UPS異(yi)常，電(dian)(dian)(dian)(dian)(dian)(dian)網(wang)直接通(tong)過(guo)旁(pang)路(lu)(lu)給負(fu)載(zai)(zai)供(gong)電(dian)(dian)(dian)(dian)(dian)(dian)。

　　2 UPS充電器的(de)設計(ji)要求

　　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。輸出功率也是充電器設計需要考慮(lv)的，當然功率也很重(zhong)要。作為UPS重(zhong)要部件之一(yi)的充電器，不得不考慮(lv)成本(ben)。歸納(na)一(yi)下有(you)如下設計要求：

　　(1) 要求(qiu)輸入電壓寬泛;

　　(2) 充電(dian)器的THDI值(zhi)小(xiao)，且能承受一定市電(dian)脈沖和浪(lang)涌;

　　(3) 寬(kuan)范圍(wei)可(ke)調節的輸(shu)出電壓，輸(shu)出電流波紋較(jiao)小;

　　(4) 對輸(shu)入電壓和輸(shu)出負載有良好(hao)響應;

　　(5) 達(da)到設計的(de)功率要求(qiu);

　　(6) 效率較高(gao);

　　(7) 成(cheng)本(ben)較(jiao)低(di)。

　　3 小功率UPS充電器拓撲的選擇

　　以某公司的(de)1～3kVA功(gong)率(lv)等級(ji)的(de)UPS為(wei)(wei)例，一般(ban)選擇(ze)單端反(fan)擊拓(tuo)撲(pu)結構作為(wei)(wei)充(chong)電(dian)(dian)器，變(bian)(bian)壓(ya)器原副邊(bian)同名(ming)端相反(fan)，輸(shu)(shu)(shu)入(ru)(ru)從市電(dian)(dian)直接獲取，經(jing)過整流濾波(bo)(bo)器后得到正弦(xian)半(ban)波(bo)(bo)電(dian)(dian)壓(ya)，再變(bian)(bian)換為(wei)(wei)所需的(de)輸(shu)(shu)(shu)出電(dian)(dian)壓(ya)，如(ru)果按照不連續(xu)模式設計，變(bian)(bian)壓(ya)器原邊(bian)電(dian)(dian)感值較小且(qie)輸(shu)(shu)(shu)出端無電(dian)(dian)抗元(yuan)件，控制系統(tong)對輸(shu)(shu)(shu)入(ru)(ru)電(dian)(dian)壓(ya)和輸(shu)(shu)(shu)出負(fu)載的(de)響應(ying)要很快。

　　當VT1導通(tong)時(shi)，以(yi)輸(shu)入(ru)電(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)正半(ban)周為(wei)(wei)(wei)例(li)，輸(shu)入(ru)電(dian)(dian)(dian)(dian)流由L端經VD2、變壓(ya)(ya)(ya)器(qi)VR1原(yuan)邊(bian)(bian)VT1、R1和(he)VD4回(hui)到N端，TR原(yuan)邊(bian)(bian)產生上(shang)(shang)(shang)正下(xia)負(fu)(fu)的電(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)，原(yuan)邊(bian)(bian)電(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)為(wei)(wei)(wei)Ui(Ui為(wei)(wei)(wei)市電(dian)(dian)(dian)(dian)整(zheng)流后的半(ban)波電(dian)(dian)(dian)(dian)壓(ya)(ya)(ya))，副(fu)邊(bian)(bian)極(ji)(ji)性相應產生下(xia)正上(shang)(shang)(shang)負(fu)(fu)的電(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)，二極(ji)(ji)管VD5承(cheng)受反向(xiang)電(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)而(er)截(jie)止，VD5承(cheng)受電(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)為(wei)(wei)(wei)(Ns/Np)Ui+UB;VT1截(jie)止時(shi)，為(wei)(wei)(wei)使磁芯工作點順利返回(hui)，變壓(ya)(ya)(ya)器(qi)原(yuan)邊(bian)(bian)產生下(xia)負(fu)(fu)上(shang)(shang)(shang)正電(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)，則副(fu)邊(bian)(bian)電(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)為(wei)(wei)(wei)上(shang)(shang)(shang)正下(xia)負(fu)(fu)，副(fu)邊(bian)(bian)電(dian)(dian)(dian)(dian)流通(tong)過(guo)VD5向(xiang)電(dian)(dian)(dian)(dian)池充電(dian)(dian)(dian)(dian)。原(yuan)邊(bian)(bian)相應電(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)為(wei)(wei)(wei)下(xia)正上(shang)(shang)(shang)負(fu)(fu)，U1=-(Np/Ns)UB，則VT1承(cheng)受電(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)為(wei)(wei)(wei)(Np/Ns)UB+U1。根據原(yuan)邊(bian)(bian)線圈的伏秒平衡。

　　但是，變壓器(qi)帶來磁(ci)滯損耗(hao)和(he)繞線(xian)損耗(hao)，另外輸出電(dian)流波(bo)紋較大，整體效率不高，VT1導(dao)通時輸出靠濾波(bo)電(dian)容(rong)C1維持，要用大容(rong)量的濾波(bo)電(dian)容(rong)。

　　小功率UPS的充(chong)電(dian)(dian)(dian)器(qi)根據充(chong)電(dian)(dian)(dian)電(dian)(dian)(dian)流(liu)的打消設計成模組(zu)和充(chong)電(dian)(dian)(dian)板，為滿足UPS緊(jin)湊化的要求，降低成本(ben)，把充(chong)電(dian)(dian)(dian)器(qi)設計在(zai)功率板上將是一種選擇(ze)，輸(shu)入從母(mu)線電(dian)(dian)(dian)壓獲取。

　　DC/DC和充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)器(qi)(qi)利(li)用一(yi)(yi)個(ge)拓撲(pu)實現(xian)，即(ji)推(tui)(tui)(tui)挽正激電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)，它在(zai)推(tui)(tui)(tui)挽電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)的基礎上變更了(le)線阻(zu)N1、N2與開(kai)(kai)(kai)關(guan)管(guan)(guan)VT1、VT2的為(wei)(wei)之(zhi)，增加了(le)一(yi)(yi)個(ge)儲(chu)能(neng)(neng)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)容C1。為(wei)(wei)了(le)形成(cheng)雙向電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)，在(zai)高(gao)壓側增加一(yi)(yi)個(ge)開(kai)(kai)(kai)關(guan)管(guan)(guan)VT4，低電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓側增加一(yi)(yi)個(ge)輔(fu)助充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)繞組(zu)和開(kai)(kai)(kai)關(guan)管(guan)(guan)VT3，形成(cheng)正激充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)，給電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)。電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)I1路(lu)徑如(ru)圖(tu)4所示。充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)時(shi)(shi)(shi)，VT3一(yi)(yi)直打開(kai)(kai)(kai)，VT4進行PWM調制(zhi)，繞組(zu)N5電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓大(da)(da)(da)于(yu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓，給電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian);對于(yu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池模式下的推(tui)(tui)(tui)挽正激電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)，以VT1管(guan)(guan)和N1支路(lu)為(wei)(wei)例，當VT1管(guan)(guan)開(kai)(kai)(kai)通時(shi)(shi)(shi)，電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)通過N1、VT1，在(zai)繞組(zu)N4感(gan)應出(chu)(chu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓給電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)容C2充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian);VT1關(guan)閉瞬間(jian)，電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)通過N1、C1、VT2體內二極(ji)管(guan)(guan)續流(liu)，當VT2開(kai)(kai)(kai)通時(shi)(shi)(shi)，C1電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)功過N1、VT2放電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)，在(zai)繞線N3感(gan)應出(chu)(chu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓給C2充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)，路(lu)徑見圖(tu)中(zhong)I2。C1電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)容在(zai)VT1、VT2關(guan)斷時(shi)(shi)(shi)刻儲(chu)能(neng)(neng)，當相(xiang)應對管(guan)(guan)開(kai)(kai)(kai)通時(shi)(shi)(shi)刻放電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)，由此提高(gao)了(le)效率(lv)，限制(zhi)了(le)開(kai)(kai)(kai)關(guan)管(guan)(guan)關(guan)斷時(shi)(shi)(shi)漏極(ji)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓過大(da)(da)(da)。這種拓撲(pu)尤其(qi)適合低電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓大(da)(da)(da)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)場合，因此可以減少電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池節(jie)數，降低成(cheng)本。另外，提高(gao)了(le)變壓器(qi)(qi)的利(li)用率(lv)，充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)時(shi)(shi)(shi)充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)器(qi)(qi)輸出(chu)(chu)端沒有接輸出(chu)(chu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)感(gan)，充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)波紋過大(da)(da)(da)。

　　4 中功率(lv)UPS充電器拓撲選擇

　　一般(ban)UPS的(de)(de)(de)電(dian)(dian)(dian)池節(jie)(jie)數是固定的(de)(de)(de)，像1kVA的(de)(de)(de)UPS配備(bei)2或(huo)3節(jie)(jie)電(dian)(dian)(dian)池，3kVA的(de)(de)(de)UPS配備(bei)6或(huo)8節(jie)(jie)，10kVA配備(bei)16或(huo)20節(jie)(jie)，中功率UPS所配備(bei)的(de)(de)(de)電(dian)(dian)(dian)池節(jie)(jie)數較多，時間長了(le)，難免(mian)有電(dian)(dian)(dian)池損(sun)壞(huai)，要求相對(dui)應的(de)(de)(de)充電(dian)(dian)(dian)器(qi)(qi)電(dian)(dian)(dian)壓能做出(chu)調整。某品牌10kVA UPS，電(dian)(dian)(dian)池在(zai)12-24節(jie)(jie)數范圍(wei)可(ke)調，對(dui)應充電(dian)(dian)(dian)器(qi)(qi)輸出(chu)電(dian)(dian)(dian)壓范圍(wei)為164-328V，單(dan)端(duan)反激拓撲輸出(chu)電(dian)(dian)(dian)壓幾(ji)乎不(bu)可(ke)能在(zai)此寬范圍(wei)可(ke)調，為此設計了(le)BOOST-BUCK變換器(qi)(qi)。

　　前(qian)級采(cai)用BOOST結(jie)構，把市電(dian)(dian)(dian)(dian)升(sheng)到400V，市電(dian)(dian)(dian)(dian)經整流橋后(hou)(hou)得到直流脈動電(dian)(dian)(dian)(dian)壓，VT1導通(tong)時(shi)，L1上電(dian)(dian)(dian)(dian)流增加，并(bing)(bing)儲存能量(liang)(liang)，VD5承(cheng)受(shou)反向電(dian)(dian)(dian)(dian)壓而截止，濾波(bo)電(dian)(dian)(dian)(dian)容(rong)C2給(gei)負(fu)載提(ti)供能量(liang)(liang);VT1截止時(shi)，市電(dian)(dian)(dian)(dian)通(tong)過L1和VD5對電(dian)(dian)(dian)(dian)池充(chong)電(dian)(dian)(dian)(dian)，并(bing)(bing)給(gei)負(fu)載提(ti)供能量(liang)(liang)，輸(shu)入和輸(shu)出(chu)關系見(jian)式(shi)。后(hou)(hou)級采(cai)用BUCK結(jie)構，它把輸(shu)入端(duan)400V降到所(suo)需的充(chong)電(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)壓，VT2導通(tong)時(shi)，VD5承(cheng)受(shou)反向電(dian)(dian)(dian)(dian)壓截止，輸(shu)入經過L2給(gei)電(dian)(dian)(dian)(dian)容(rong)C2充(chong)電(dian)(dian)(dian)(dian)，并(bing)(bing)提(ti)供能量(liang)(liang)給(gei)負(fu)載，VT2截止時(shi)，電(dian)(dian)(dian)(dian)感電(dian)(dian)(dian)(dian)流經過VD6續流，L2和C2共同負(fu)載提(ti)供能量(liang)(liang)，輸(shu)入輸(shu)出(chu)關系見(jian)式(shi)，聯立(li)式(shi)和式(shi)可得充(chong)電(dian)(dian)(dian)(dian)器(qi)輸(shu)入輸(shu)出(chu)關系，見(jian)式(shi)，D1不變，D2可變。

　　結束語

　　小(xiao)功(gong)率(lv)UPS不要求寬范圍的輸(shu)(shu)出(chu)(chu)電壓(ya)(ya)，希望對(dui)輸(shu)(shu)入電壓(ya)(ya)和(he)(he)輸(shu)(shu)出(chu)(chu)負載有良(liang)好(hao)相(xiang)應(ying)，單端反(fan)激(ji)拓(tuo)撲(pu)能(neng)(neng)滿足此要求，盡(jin)管其(qi)輸(shu)(shu)出(chu)(chu)功(gong)率(lv)和(he)(he)效率(lv)不高;推挽正激(ji)拓(tuo)撲(pu)同時實現了充電器和(he)(he)DC/DC的功(gong)能(neng)(neng)，減(jian)(jian)低(di)了整機成本;中功(gong)率(lv)UPS則(ze)希望充電器輸(shu)(shu)出(chu)(chu)電壓(ya)(ya)可調，BOOST-BUCK和(he)(he)BOOST-半(ban)橋都是明智的選擇;大(da)功(gong)率(lv)UPS采用模(mo)塊化結構，對(dui)THDI和(he)(he)輸(shu)(shu)入功(gong)率(lv)因數等指標要求很高，輸(shu)(shu)入取(qu)自(zi)母線電壓(ya)(ya)的BUCK變換器拓(tuo)撲(pu)簡單實用，當然，BOOST一半(ban)橋在縮減(jian)(jian)模(mo)塊體積方(fang)面表現突出(chu)(chu)。