作為UPS關鍵部件的充電器與(yu)UPS的許多指(zhi)標密(mi)切相關。文(wen)章(zhang)提出了(le)UPS充電器的設計要求，將UPS按功(gong)率大(da)小劃分(fen)，分(fen)別為(wei)它們選擇了(le)合適的充電器拓撲，并(bing)分(fen)析了(le)工作原理，指(zhi)出了(le)存在的不(bu)足。

　　1 在線式UPS的組成

　　隨著電(dian)(dian)(dian)(dian)(dian)(dian)子技(ji)術的(de)(de)(de)飛(fei)速發展(zhan)，各種(zhong)各樣(yang)的(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)器設備越來(lai)越多，而這(zhe)(zhe)其中的(de)(de)(de)大部(bu)分都(dou)是非線性負(fu)載(zai)，即它們從電(dian)(dian)(dian)(dian)(dian)(dian)網(wang)汲取的(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)流波(bo)形(xing)與(yu)電(dian)(dian)(dian)(dian)(dian)(dian)壓波(bo)形(xing)不一樣(yang)。這(zhe)(zhe)無(wu)疑(yi)給電(dian)(dian)(dian)(dian)(dian)(dian)網(wang)帶來(lai)了(le)大量(liang)(liang)的(de)(de)(de)諧波(bo)以及其他的(de)(de)(de)公害，使供電(dian)(dian)(dian)(dian)(dian)(dian)的(de)(de)(de)質(zhi)量(liang)(liang)變得較差。另一方面，一些(xie)重要(yao)的(de)(de)(de)用(yong)電(dian)(dian)(dian)(dian)(dian)(dian)部(bu)門(如(ru)機場、醫院、銀行(xing))和一些(xie)重要(yao)的(de)(de)(de)用(yong)電(dian)(dian)(dian)(dian)(dian)(dian)設備(如(ru)計(ji)算機、通信設備)對供電(dian)(dian)(dian)(dian)(dian)(dian)質(zhi)量(liang)(liang)的(de)(de)(de)要(yao)求越來(lai)越高，不僅要(yao)求不停電(dian)(dian)(dian)(dian)(dian)(dian)，還(huan)要(yao)求電(dian)(dian)(dian)(dian)(dian)(dian)壓、頻率(lv)、波(bo)形(xing)質(zhi)量(liang)(liang)良好(hao)，避免(mian)受到電(dian)(dian)(dian)(dian)(dian)(dian)網(wang)的(de)(de)(de)干擾，具備一個凈化的(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)源環境。這(zhe)(zhe)就使負(fu)載(zai)與(yu)電(dian)(dian)(dian)(dian)(dian)(dian)網(wang)供電(dian)(dian)(dian)(dian)(dian)(dian)質(zhi)量(liang)(liang)之間的(de)(de)(de)矛盾(dun)日益加劇。為解(jie)決這(zhe)(zhe)一矛盾(dun)，UPS供電(dian)(dian)(dian)(dian)(dian)(dian)系(xi)統迅猛發展(zhan)并普及起來(lai)。

　　隨(sui)著(zhu)計算(suan)機、各(ge)種辦(ban)公設備、精密電(dian)(dian)(dian)(dian)子儀(yi)器(qi)的(de)普(pu)及，UPS得到了廣泛(fan)的(de)應(ying)用(yong)。現在應(ying)用(yong)較(jiao)多的(de)是(shi)在線(xian)式UPS，當市電(dian)(dian)(dian)(dian)正常(chang)時，電(dian)(dian)(dian)(dian)網(wang)電(dian)(dian)(dian)(dian)壓(ya)一路經過(guo)整流模(mo)塊(kuai)AC/DC、逆變(bian)模(mo)塊(kuai)DC/AC，得到所需的(de)正弦電(dian)(dian)(dian)(dian)壓(ya)或(huo)準方(fang)波(bo)電(dian)(dian)(dian)(dian)壓(ya)供給(gei)負(fu)載(zai)(zai)，另一路通(tong)過(guo)充(chong)(chong)電(dian)(dian)(dian)(dian)模(mo)塊(kuai)給(gei)電(dian)(dian)(dian)(dian)池充(chong)(chong)電(dian)(dian)(dian)(dian);市電(dian)(dian)(dian)(dian)異常(chang)時，電(dian)(dian)(dian)(dian)池通(tong)過(guo)DC/DC模(mo)塊(kuai)、DC/AC模(mo)塊(kuai)，輸出正弦電(dian)(dian)(dian)(dian)壓(ya)或(huo)準方(fang)波(bo)電(dian)(dian)(dian)(dian)壓(ya)，給(gei)負(fu)載(zai)(zai)供電(dian)(dian)(dian)(dian);如果(guo)UPS異常(chang)，電(dian)(dian)(dian)(dian)網(wang)直接通(tong)過(guo)旁路給(gei)負(fu)載(zai)(zai)供電(dian)(dian)(dian)(dian)。

　　2 UPS充電器的設計要(yao)求(qiu)

　　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(gong)率也是充電(dian)器設計需(xu)要(yao)考慮的，當然功(gong)率也很(hen)重要(yao)。作為(wei)UPS重要(yao)部件(jian)之(zhi)一的充電(dian)器，不(bu)得不(bu)考慮成本(ben)。歸納一下有如下設計要(yao)求：

　　(1) 要求輸入電壓(ya)寬泛;

　　(2) 充電器的THDI值小(xiao)，且(qie)能(neng)承(cheng)受一定市(shi)電脈沖和浪涌;

　　(3) 寬范圍可調節的(de)輸出(chu)電(dian)壓，輸出(chu)電(dian)流波(bo)紋較小(xiao);

　　(4) 對輸入電壓(ya)和輸出負載有良(liang)好響應;

　　(5) 達到設計的功率要(yao)求(qiu);

　　(6) 效(xiao)率較高;

　　(7) 成本較低。

　　3 小功率UPS充電器拓撲的選擇

　　以某公司的(de)(de)1～3kVA功(gong)率(lv)等級的(de)(de)UPS為(wei)例(li)，一般選擇單端反擊拓撲(pu)結構作為(wei)充電器(qi)，變(bian)壓(ya)器(qi)原副邊同(tong)名端相反，輸(shu)(shu)入(ru)從市電直(zhi)接獲(huo)取，經(jing)過整流濾波器(qi)后得(de)到正弦半波電壓(ya)，再變(bian)換為(wei)所需的(de)(de)輸(shu)(shu)出(chu)電壓(ya)，如果按(an)照不連續模式設(she)計，變(bian)壓(ya)器(qi)原邊電感值較小且輸(shu)(shu)出(chu)端無電抗元件，控制系(xi)統對輸(shu)(shu)入(ru)電壓(ya)和(he)輸(shu)(shu)出(chu)負(fu)載(zai)的(de)(de)響應(ying)要很快(kuai)。

　　當VT1導通時(shi)(shi)，以輸入(ru)電(dian)(dian)(dian)壓(ya)正(zheng)半(ban)周(zhou)為(wei)(wei)例，輸入(ru)電(dian)(dian)(dian)流(liu)由(you)L端(duan)經VD2、變(bian)壓(ya)器(qi)VR1原(yuan)邊VT1、R1和VD4回到N端(duan)，TR原(yuan)邊產生(sheng)上(shang)(shang)正(zheng)下負(fu)的(de)電(dian)(dian)(dian)壓(ya)，原(yuan)邊電(dian)(dian)(dian)壓(ya)為(wei)(wei)Ui(Ui為(wei)(wei)市電(dian)(dian)(dian)整流(liu)后的(de)半(ban)波電(dian)(dian)(dian)壓(ya))，副邊極性(xing)相應產生(sheng)下正(zheng)上(shang)(shang)負(fu)的(de)電(dian)(dian)(dian)壓(ya)，二極管VD5承受反向電(dian)(dian)(dian)壓(ya)而截(jie)止(zhi)，VD5承受電(dian)(dian)(dian)壓(ya)為(wei)(wei)(Ns/Np)Ui+UB;VT1截(jie)止(zhi)時(shi)(shi)，為(wei)(wei)使磁芯(xin)工作點順利返回，變(bian)壓(ya)器(qi)原(yuan)邊產生(sheng)下負(fu)上(shang)(shang)正(zheng)電(dian)(dian)(dian)壓(ya)，則副邊電(dian)(dian)(dian)壓(ya)為(wei)(wei)上(shang)(shang)正(zheng)下負(fu)，副邊電(dian)(dian)(dian)流(liu)通過VD5向電(dian)(dian)(dian)池充電(dian)(dian)(dian)。原(yuan)邊相應電(dian)(dian)(dian)壓(ya)為(wei)(wei)下正(zheng)上(shang)(shang)負(fu)，U1=-(Np/Ns)UB，則VT1承受電(dian)(dian)(dian)壓(ya)為(wei)(wei)(Np/Ns)UB+U1。根據原(yuan)邊線圈的(de)伏秒平衡。

　　但是，變壓器帶(dai)來磁滯損(sun)耗(hao)和繞線損(sun)耗(hao)，另外輸出電(dian)流(liu)波紋較(jiao)大，整體效率(lv)不(bu)高，VT1導通(tong)時(shi)輸出靠濾(lv)波電(dian)容(rong)C1維持，要用大容(rong)量的濾(lv)波電(dian)容(rong)。

　　小功率UPS的充電(dian)器根據充電(dian)電(dian)流的打消設(she)計(ji)成(cheng)模組和充電(dian)板，為滿足UPS緊湊(cou)化的要求，降低成(cheng)本(ben)，把充電(dian)器設(she)計(ji)在功率板上將是一種(zhong)選擇(ze)，輸入從母線電(dian)壓(ya)獲取。

　　DC/DC和(he)充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)器利(li)用一(yi)(yi)個(ge)(ge)拓撲實現，即推挽正激(ji)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)(lu)(lu)，它在推挽電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)(lu)(lu)的基礎上變更了(le)(le)線阻N1、N2與(yu)開(kai)關(guan)(guan)管(guan)VT1、VT2的為(wei)之(zhi)，增(zeng)加(jia)了(le)(le)一(yi)(yi)個(ge)(ge)儲(chu)能電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)容(rong)C1。為(wei)了(le)(le)形成雙向電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)(lu)(lu)，在高壓(ya)(ya)側增(zeng)加(jia)一(yi)(yi)個(ge)(ge)開(kai)關(guan)(guan)管(guan)VT4，低(di)(di)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)側增(zeng)加(jia)一(yi)(yi)個(ge)(ge)輔助(zhu)充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)繞組(zu)和(he)開(kai)關(guan)(guan)管(guan)VT3，形成正激(ji)充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)(lu)(lu)，給電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)。電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)(lu)(lu)I1路(lu)(lu)(lu)(lu)徑如(ru)圖4所示。充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)時，VT3一(yi)(yi)直打開(kai)，VT4進(jin)行PWM調(diao)制，繞組(zu)N5電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)大于電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)，給電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian);對于電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池模式下(xia)的推挽正激(ji)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)(lu)(lu)，以VT1管(guan)和(he)N1支(zhi)路(lu)(lu)(lu)(lu)為(wei)例(li)，當VT1管(guan)開(kai)通(tong)(tong)(tong)時，電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)通(tong)(tong)(tong)過(guo)(guo)N1、VT1，在繞組(zu)N4感(gan)應出電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)給電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)容(rong)C2充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian);VT1關(guan)(guan)閉瞬間，電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)通(tong)(tong)(tong)過(guo)(guo)N1、C1、VT2體內(nei)二極管(guan)續流(liu)，當VT2開(kai)通(tong)(tong)(tong)時，C1電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)功(gong)過(guo)(guo)N1、VT2放電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)，在繞線N3感(gan)應出電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)給C2充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)，路(lu)(lu)(lu)(lu)徑見圖中I2。C1電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)容(rong)在VT1、VT2關(guan)(guan)斷時刻儲(chu)能，當相(xiang)應對管(guan)開(kai)通(tong)(tong)(tong)時刻放電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)，由此提高了(le)(le)效率，限制了(le)(le)開(kai)關(guan)(guan)管(guan)關(guan)(guan)斷時漏極電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)過(guo)(guo)大。這種拓撲尤其適合低(di)(di)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)大電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)場合，因此可(ke)以減少電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池節數，降低(di)(di)成本(ben)。另(ling)外，提高了(le)(le)變壓(ya)(ya)器的利(li)用率，充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)時充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)器輸(shu)出端沒有接(jie)輸(shu)出電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)感(gan)，充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)波紋(wen)過(guo)(guo)大。

　　4 中功率UPS充(chong)電器拓撲選擇

　　一般UPS的(de)(de)電(dian)池(chi)節(jie)(jie)(jie)數(shu)是(shi)固定的(de)(de)，像1kVA的(de)(de)UPS配備2或(huo)3節(jie)(jie)(jie)電(dian)池(chi)，3kVA的(de)(de)UPS配備6或(huo)8節(jie)(jie)(jie)，10kVA配備16或(huo)20節(jie)(jie)(jie)，中(zhong)功率(lv)UPS所配備的(de)(de)電(dian)池(chi)節(jie)(jie)(jie)數(shu)較多(duo)，時間長了，難免有電(dian)池(chi)損壞，要求相對應的(de)(de)充(chong)電(dian)器電(dian)壓(ya)能(neng)做出調(diao)整。某品(pin)牌10kVA UPS，電(dian)池(chi)在12-24節(jie)(jie)(jie)數(shu)范圍可(ke)調(diao)，對應充(chong)電(dian)器輸(shu)出電(dian)壓(ya)范圍為164-328V，單端反(fan)激拓撲輸(shu)出電(dian)壓(ya)幾(ji)乎不可(ke)能(neng)在此寬范圍可(ke)調(diao)，為此設計(ji)了BOOST-BUCK變(bian)換器。

　　前級采(cai)用BOOST結(jie)構(gou)，把(ba)市(shi)電(dian)(dian)(dian)(dian)(dian)升(sheng)到400V，市(shi)電(dian)(dian)(dian)(dian)(dian)經整流(liu)橋(qiao)后得到直(zhi)流(liu)脈動電(dian)(dian)(dian)(dian)(dian)壓，VT1導通時(shi)，L1上(shang)電(dian)(dian)(dian)(dian)(dian)流(liu)增加，并儲存能(neng)(neng)量(liang)(liang)，VD5承(cheng)受(shou)反向電(dian)(dian)(dian)(dian)(dian)壓而(er)截止(zhi)，濾波(bo)電(dian)(dian)(dian)(dian)(dian)容C2給(gei)負載提(ti)供能(neng)(neng)量(liang)(liang);VT1截止(zhi)時(shi)，市(shi)電(dian)(dian)(dian)(dian)(dian)通過(guo)(guo)L1和(he)VD5對電(dian)(dian)(dian)(dian)(dian)池充(chong)電(dian)(dian)(dian)(dian)(dian)，并給(gei)負載提(ti)供能(neng)(neng)量(liang)(liang)，輸(shu)(shu)入(ru)和(he)輸(shu)(shu)出(chu)關系(xi)見式(shi)。后級采(cai)用BUCK結(jie)構(gou)，它把(ba)輸(shu)(shu)入(ru)端400V降到所需的(de)充(chong)電(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)壓，VT2導通時(shi)，VD5承(cheng)受(shou)反向電(dian)(dian)(dian)(dian)(dian)壓截止(zhi)，輸(shu)(shu)入(ru)經過(guo)(guo)L2給(gei)電(dian)(dian)(dian)(dian)(dian)容C2充(chong)電(dian)(dian)(dian)(dian)(dian)，并提(ti)供能(neng)(neng)量(liang)(liang)給(gei)負載，VT2截止(zhi)時(shi)，電(dian)(dian)(dian)(dian)(dian)感電(dian)(dian)(dian)(dian)(dian)流(liu)經過(guo)(guo)VD6續(xu)流(liu)，L2和(he)C2共同負載提(ti)供能(neng)(neng)量(liang)(liang)，輸(shu)(shu)入(ru)輸(shu)(shu)出(chu)關系(xi)見式(shi)，聯立(li)式(shi)和(he)式(shi)可得充(chong)電(dian)(dian)(dian)(dian)(dian)器(qi)輸(shu)(shu)入(ru)輸(shu)(shu)出(chu)關系(xi)，見式(shi)，D1不變(bian)，D2可變(bian)。

　　結束語

　　小功(gong)(gong)率(lv)UPS不(bu)(bu)要(yao)求(qiu)(qiu)寬范圍(wei)的(de)輸(shu)(shu)出(chu)(chu)電(dian)壓，希望(wang)對輸(shu)(shu)入電(dian)壓和(he)輸(shu)(shu)出(chu)(chu)負載有良好相應，單(dan)端反激拓(tuo)撲能滿足此要(yao)求(qiu)(qiu)，盡管其輸(shu)(shu)出(chu)(chu)功(gong)(gong)率(lv)和(he)效率(lv)不(bu)(bu)高;推挽正激拓(tuo)撲同時(shi)實現了充電(dian)器和(he)DC/DC的(de)功(gong)(gong)能，減低了整機成(cheng)本;中功(gong)(gong)率(lv)UPS則希望(wang)充電(dian)器輸(shu)(shu)出(chu)(chu)電(dian)壓可調(diao)，BOOST-BUCK和(he)BOOST-半橋都是明智的(de)選擇;大功(gong)(gong)率(lv)UPS采用模塊(kuai)化結構(gou)，對THDI和(he)輸(shu)(shu)入功(gong)(gong)率(lv)因(yin)數(shu)等指標(biao)要(yao)求(qiu)(qiu)很高，輸(shu)(shu)入取自(zi)母線電(dian)壓的(de)BUCK變換器拓(tuo)撲簡單(dan)實用，當然，BOOST一半橋在(zai)縮(suo)減模塊(kuai)體(ti)積(ji)方面(mian)表(biao)現突出(chu)(chu)。