UPS電源系統
UPS電源(yuan)系統由4部分組成:整(zheng)流(liu)、儲能、變換和(he)開關控制。其系統的穩壓功能通(tong)常是由整(zheng)流(liu)器(qi)(qi)完成的,整(zheng)流(liu)器(qi)(qi)件采(cai)用可控硅或高頻(pin)開關整(zheng)流(liu)器(qi)(qi),本身具有可根據外(wai)電的變化控制輸出幅度(du)(du)的功能,從而當(dang)外(wai)電發生(sheng)變化時(該變化應滿足系統要求),輸出幅度(du)(du)基本不(bu)變的整(zheng)流(liu)電壓。
凈化(hua)功能(neng)(neng)由儲(chu)(chu)能(neng)(neng)電池來完成,由于整流(liu)器(qi)對瞬時脈(mo)沖干(gan)(gan)擾(rao)不(bu)能(neng)(neng)消除,整流(liu)后的(de)電壓(ya)仍存在干(gan)(gan)擾(rao)脈(mo)沖。儲(chu)(chu)能(neng)(neng)電池除可存儲(chu)(chu)直流(liu)直能(neng)(neng)的(de)功能(neng)(neng)外(wai),對整流(liu)器(qi)來說就(jiu)像(xiang)接了(le)一只大(da)容器(qi)電容器(qi),其(qi)等效電容量(liang)的(de)大(da)小,與儲(chu)(chu)能(neng)(neng)電池容量(liang)大(da)小成正比。
由于電(dian)容(rong)兩端的(de)電(dian)壓(ya)是不能突(tu)變(bian)(bian)的(de),即利用了(le)電(dian)容(rong)器對脈(mo)沖的(de)平滑特性(xing)消除了(le)脈(mo)沖干擾,起到了(le)凈化功(gong)能,也(ye)稱對干擾的(de)屏蔽(bi)。頻(pin)(pin)率的(de)穩(wen)定(ding)則由變(bian)(bian)換器來完成,頻(pin)(pin)率穩(wen)定(ding)度取(qu)決于變(bian)(bian)換器的(de)振(zhen)蕩(dang)頻(pin)(pin)率的(de)穩(wen)定(ding)程度。為(wei)方便UPS電(dian)源(yuan)系(xi)統的(de)日常操作(zuo)與維(wei)護,設(she)計了(le)系(xi)統工作(zuo)開(kai)關(guan),主機(ji)自檢故障后的(de)自動旁路開(kai)關(guan),檢修旁路開(kai)關(guan)等開(kai)關(guan)控制。
在電(dian)(dian)網電(dian)(dian)壓工(gong)(gong)作正常時,給負(fu)載(zai)(zai)供電(dian)(dian),而且,同時給儲能(neng)電(dian)(dian)池充電(dian)(dian);當突發(fa)停電(dian)(dian)時,UPS電(dian)(dian)源開始工(gong)(gong)作,由(you)儲能(neng)電(dian)(dian)池工(gong)(gong)給負(fu)載(zai)(zai)所需電(dian)(dian)源,維持正常的生產;當由(you)于生產需要,負(fu)載(zai)(zai)嚴重過載(zai)(zai)時,由(you)電(dian)(dian)網電(dian)(dian)壓經整流直接給負(fu)載(zai)(zai)供電(dian)(dian)。
UPS電源工作原理
1、AC-DC變換:將電(dian)(dian)網來的交(jiao)流(liu)電(dian)(dian)經自耦變(bian)壓器降壓、全(quan)波整流(liu)、濾波變(bian)為直流(liu)電(dian)(dian)壓,供給逆(ni)變(bian)電(dian)(dian)路。AC-DC輸入有軟啟動電(dian)(dian)路,可(ke)避(bi)免(mian)開機時對電(dian)(dian)網的沖擊。
2、DC-AC逆變電路:采用大(da)功率IGBT模(mo)塊全橋逆(ni)變電路(lu),具有很(hen)大(da)的功率富余量,在輸出(chu)動態范圍內輸出(chu)阻抗特別(bie)小,具有快速(su)響應特性(xing)。由(you)于采用高(gao)頻調制(zhi)限流技(ji)術,及快速(su)短(duan)路(lu)保護(hu)技(ji)術,使逆(ni)變器無論是(shi)供電電壓瞬變還是(shi)負載沖擊或短(duan)路(lu),均(jun)可安全可靠地工(gong)作。
3、控制驅動:控(kong)(kong)制驅(qu)動是完(wan)成(cheng)整機功能控(kong)(kong)制的核心,它除了提(ti)供(gong)檢測、保護、同步以及各種(zhong)開關(guan)和(he)顯示驅(qu)動信號外,還完(wan)成(cheng)SPWM正弦脈寬(kuan)調(diao)制的控(kong)(kong)制,由(you)于采用靜態和(he)動態雙重電壓反饋。極大地(di)改善了逆變器的動態特性和(he)穩定性。
UPS電源工作過程
當(dang)市(shi)(shi)電(dian)(dian)(dian)正常380Vac時,直流(liu)(liu)(liu)主回路(lu)有直流(liu)(liu)(liu)電(dian)(dian)(dian)壓(ya),供(gong)給DC-AC交流(liu)(liu)(liu)逆(ni)變(bian)器(qi),輸出穩定(ding)的220Vac交流(liu)(liu)(liu)電(dian)(dian)(dian)壓(ya),同時市(shi)(shi)電(dian)(dian)(dian)對電(dian)(dian)(dian)流(liu)(liu)(liu)充電(dian)(dian)(dian)。當(dang)任何時候市(shi)(shi)電(dian)(dian)(dian)欠(qian)壓(ya)或突然掉(diao)電(dian)(dian)(dian),則由電(dian)(dian)(dian)池(chi)(chi)組通過隔離二極(ji)管開關向直流(liu)(liu)(liu)回路(lu)饋(kui)送電(dian)(dian)(dian)能(neng)。從電(dian)(dian)(dian)網供(gong)電(dian)(dian)(dian)到電(dian)(dian)(dian)池(chi)(chi)供(gong)電(dian)(dian)(dian)沒有切換(huan)時間。當(dang)電(dian)(dian)(dian)池(chi)(chi)能(neng)量即將耗(hao)盡(jin)時,不(bu)間斷電(dian)(dian)(dian)源(yuan)發出聲(sheng)光(guang)報警(jing)(jing),并在電(dian)(dian)(dian)池(chi)(chi)放電(dian)(dian)(dian)下限(xian)點(dian)停止逆(ni)變(bian)器(qi)工作,長鳴告警(jing)(jing)。
不(bu)間斷(duan)電(dian)源(yuan)還有過載(zai)(zai)(zai)保護(hu)功(gong)能,當發生(sheng)超載(zai)(zai)(zai)(150%負(fu)載(zai)(zai)(zai))時,跳(tiao)到旁(pang)路狀態(tai),并在負(fu)載(zai)(zai)(zai)正常時自動(dong)返回(hui)。當發生(sheng)嚴重超載(zai)(zai)(zai)(超過200%額定(ding)負(fu)載(zai)(zai)(zai))時,不(bu)間斷(duan)電(dian)源(yuan)立即停止逆變器輸出并跳(tiao)到旁(pang)路狀態(tai),此(ci)時前面空(kong)氣開關也可能跳(tiao)閘(zha)。消除故障后,只要(yao)合上(shang)開關,重新開機(ji)即開始恢復工作。為使不(bu)間斷(duan)電(dian)源(yuan)充分(fen)工作,避免在過載(zai)(zai)(zai)或欠載(zai)(zai)(zai)下運(yun)行,電(dian)源(yuan)在開機(ji)前,首先計算(suan)負(fu)載(zai)(zai)(zai)容量。FR-UK型不(bu)間斷(duan)電(dian)源(yuan)(標稱額定(ding)功(gong)率)80%的(de)阻性(xing)負(fu)載(zai)(zai)(zai)設計負(fu)載(zai)(zai)(zai)能力,一般帶計算(suan)機(ji)負(fu)載(zai)(zai)(zai)時可承受的(de)按下式估(gu)算(suan):
∑i=1 n Pi≤P
其中(zhong)P為不間斷電源輸出容量(VA),P為第(di)i個負載(zai)伏安數
每套PLC功率: 220V*0.5=110VA
每臺操作站功率(lv): 220V*2A=440VA
IBM PC客(ke)戶機及服(fu)務器(qi):220V*1.5A=330VA
則總功(gong)率(lv):10*110VA+4*440VA+11*330VA=6?90VA
6?90VA/0.8=8112VA
因此,在這條棒(bang)材生產(chan)線(xian)上,采用(yong)10KVA的不間斷電源(yuan)比較(jiao)合適。
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