ups不間斷電源電路工作原理
常態(tai)下(xia),市(shi)電(dian)(dian)(dian)(dian)(220V)通過(guo)可調充(chong)電(dian)(dian)(dian)(dian)器(qi)(qi)向(xiang)蓄電(dian)(dian)(dian)(dian)池充(chong)電(dian)(dian)(dian)(dian),同時自啟動繼電(dian)(dian)(dian)(dian)器(qi)(qi)K1吸(xi)(xi)合(he),R1與(yu)VZ1、VZ2對蓄電(dian)(dian)(dian)(dian)池+24V電(dian)(dian)(dian)(dian)壓進行分壓采(cai)樣(yang),采(cai)樣(yang)電(dian)(dian)(dian)(dian)壓Vo通過(guo)R2、VD3加到V1基極,使V1處于線性放大狀態(tai),V2、V3深度飽和,直(zhi)流控制繼電(dian)(dian)(dian)(dian)器(qi)(qi)K吸(xi)(xi)合(he),+24V電(dian)(dian)(dian)(dian)壓通過(guo)K、K1送至(zhi)逆變器(qi)(qi)V+端,逆變器(qi)(qi)工(gong)作,輸(shu)出220V正弦波電(dian)(dian)(dian)(dian)壓,同時自鎖(suo)繼電(dian)(dian)(dian)(dian)器(qi)(qi)K2吸(xi)(xi)合(he)。
當(dang)市電(dian)(dian)斷電(dian)(dian)時,K1斷開(kai),初(chu)時輸人電(dian)(dian)壓+24V不變(bian),K繼續吸合,由于K2的自鎖作用(yong),+24V仍正常送至逆變(bian)器。經(jing)一(yi)段時間后(hou),電(dian)(dian)池電(dian)(dian)壓開(kai)始下降,Vo跟(gen)著(zhu)下降,V1導(dao)通(tong)減弱,V2升(sheng)(sheng)高(gao);當(dang)嘰升(sheng)(sheng)高(gao)至一(yi)定值(即蓄(xu)電(dian)(dian)池電(dian)(dian)壓下降至22V)后(hou),V2退出飽和進人線性放大(da),V3迅速下降;V3通(tong)過R7反饋至V1基極,使得V2繼續升(sheng)(sheng)高(gao),形成一(yi)個雪崩過程。
V2、V3迅速截(jie)止(zhi),K斷開,蓄(xu)電(dian)(dian)池送至逆變器(qi)的+24V直(zhi)流被(bei)切斷,逆變器(qi)停止(zhi)工作(zuo),同時K2斷開。逆變器(qi)停止(zhi)工作(zuo)后(hou),由于(yu)蓄(xu)電(dian)(dian)池內電(dian)(dian)動勢的作(zuo)用,蓄(xu)電(dian)(dian)池很快(kuai)恢復24V電(dian)(dian)壓,與常態一(yi)樣,V2、V3飽和,K吸合(he)。
但由于此(ci)時K1、K2均斷(duan)開,+24V無法到達逆變器,逆變器不(bu)工作,從而保(bao)護了蓄(xu)電池(chi)。只有當(dang)市電恢復正常(chang)后(hou),K1吸合(he),逆變器才能工作,此(ci)時充電器已向蓄(xu)電池(chi)充電。
調整R1可在市電斷(duan)電時(shi)(shi)校準蓄電池(chi)電壓下(xia)限保護起控值(zhi),亦同時(shi)(shi)調整市電斷(duan)電時(shi)(shi)UPS的最長工(gong)作時(shi)(shi)間(jian)。
元器(qi)(qi)(qi)件選(xuan)(xuan)(xuan)擇:充(chong)(chong)電(dian)(dian)器(qi)(qi)(qi)選(xuan)(xuan)(xuan)用(yong)市售24~12V/50A可調充(chong)(chong)電(dian)(dian)器(qi)(qi)(qi);逆(ni)變器(qi)(qi)(qi)選(xuan)(xuan)(xuan)用(yong)功率(lv)500V·A、直流工作(zuo)電(dian)(dian)壓為24V逆(ni)變器(qi)(qi)(qi);蓄電(dian)(dian)池(chi)選(xuan)(xuan)(xuan)用(yong)兩個12.80A·h鉛蓄電(dian)(dian)池(chi)串接;交(jiao)流繼電(dian)(dian)器(qi)(qi)(qi)規(gui)(gui)格(ge)為220V/10A;直流繼電(dian)(dian)器(qi)(qi)(qi)規(gui)(gui)格(ge)為24V/20A。
UPS電路結構種類
當前技術成熟并已(yi)形(xing)成產(chan)品的各(ge)種UPS,就其主電路結構和不停電供電運行機(ji)制來看,主要有幾大類:
后備式
在線互動式
雙逆變在線式
雙逆變(bian)電壓(ya)補償在線式(逆變(bian)器)
1、 后備式是靜止式UPS的最初形式,因為應用得早,用得廣泛,因而技術和產品都是很成熟的。
充(chong)電器:市電存在時(shi),對(dui)蓄電池充(chong)電并浮充(chong),如果是長延時(shi)UPS,就要求它有較強的充(chong)電能(neng)力,或(huo)者外加(jia)相應容量的附加(jia)充(chong)電器。
DC-AC逆(ni)變器:市(shi)電(dian)存在時,逆(ni)變器不工作;市(shi)電(dian)掉電(dian)時,由它將直(zhi)流(liu)電(dian)壓(電(dian)池供給)變成符合(he)負載要求的交流(liu)電(dian)壓,電(dian)壓波(bo)形有方波(bo)、準方波(bo)、正弦波(bo)三種形式。
輸出(chu)轉換開關:市(shi)電(dian)(dian)存在時,接(jie)通輸入電(dian)(dian)源向負載供電(dian)(dian);市(shi)電(dian)(dian)掉(diao)電(dian)(dian)時,斷開電(dian)(dian)網(wang),接(jie)通逆(ni)變器,繼續(xu)向負載供電(dian)(dian)。 智能調(diao)壓:市(shi)電(dian)(dian)存在時,可調(diao)節穩定(ding)輸出(chu)電(dian)(dian)壓。
后備式UPS的性能特點是:
·當市電存在時,效率高,可(ke)達98%以上;
·當市(shi)電(dian)存在時(shi),輸入(ru)功率因數和輸入(ru)電(dian)流(liu)諧(xie)波取決于負載電(dian)流(liu),UPS本身不 產(chan)生附(fu)加輸入(ru)功率因數和諧(xie)波電(dian)流(liu)失真;
·當(dang)市電存在時,輸(shu)出能力強,對(dui)負載(zai)(zai)電流(liu)波峰系數(shu)(shu)、浪涌電流(liu)系數(shu)(shu)、輸(shu)出功率因(yin)數(shu)(shu)、過(guo)載(zai)(zai)等沒有嚴(yan)格地限(xian)制;
·市電掉電時(shi),輸出(chu)有轉(zhuan)換時(shi)間,一般可做到(dao)4ms左右(you),足以滿足負載要求;
·當市電存在時(shi),輸出電壓穩(wen)定精度(du)差,但能(neng)滿足負載(zai)要(yao)求;
·當市電存在時(shi),整機要靠附(fu)加濾(lv)波電路提高UPS雙向(xiang)抗干(gan)擾功能;
·電路(lu)簡(jian)單,成本低(di),可靠(kao)性高;
·由于輸(shu)出(chu)有轉換開關,受切換電流能(neng)力和動(dong)作時間的限制,UPS輸(shu)出(chu)功率(lv)做大有一(yi)定困難,當前面(mian)市的后備式UPS多在(zai)2KVA以下。
2、 在線互動式的在線含意是逆變器處于熱備份狀態,同時兼顧了對電池充電的功能,提高了后備式UPS的功率容量,減小了市電掉電時的轉換時間,提高了對輸出電壓的濾波作用。
·輸入開關:當(dang)市電(dian)(dian)掉電(dian)(dian)時(指電(dian)(dian)網(wang)失壓),斷開開關,防止逆(ni)變器(qi)向電(dian)(dian)網(wang)饋電(dian)(dian);
·智能調壓:市電存在時,可調節穩定輸出(chu)電壓;
·DC/AC逆(ni)(ni)變(bian)(bian)(bian)器:此逆(ni)(ni)變(bian)(bian)(bian)器可雙向(xiang)(xiang)逆(ni)(ni)變(bian)(bian)(bian),當市電(dian)存(cun)在時,逆(ni)(ni)變(bian)(bian)(bian)方(fang)向(xiang)(xiang)是AC- DC, 給電(dian)池充電(dian)并浮充;市電(dian)掉電(dian)后(hou),逆(ni)(ni)變(bian)(bian)(bian)方(fang)向(xiang)(xiang)為DC-AC,由電(dian)池供電(dian),保持UPS繼續向(xiang)(xiang)負(fu)載供電(dian)。
在線互動式UPS的性能特點是:
·當市電存在時,效率高(gao),可達(da)98%以上(shang);
·當市電存在時(shi),輸入功率(lv)因數(shu)(shu)和輸入電流諧波成份取決于負載 電流,UPS本(ben) 身不(bu)產生附加輸入功率(lv)因數(shu)(shu)和諧波電流失真;
·當市電(dian)存在時,輸出能力(li)強,對(dui)負載(zai)電(dian)流峰值系數(shu)、浪(lang)涌電(dian)流系數(shu)、輸出功(gong)率 因數(shu)、過載(zai)等(deng)沒有(you)嚴格地(di)限制;
·市電(dian)掉電(dian)時(shi),因為輸(shu)入開關(guan)存在開斷時(shi)間(jian),至使UPS輸(shu)出(chu)仍有轉換時(shi)間(jian),但比(bi)后備式要(yao)小(xiao);
·市電(dian)(dian)存在時,輸出電(dian)(dian)壓穩(wen)定(ding)精度(du)差,但(dan)能滿足負載(zai)要求(qiu);
·市電存在時,因為(wei)逆變器直接(jie)接(jie)在輸出端,并且處(chu)在熱備份狀況,對輸出電壓(ya)尖峰干擾有濾(lv)波作用;
·電路更簡單,成本低,可靠性高;
·逆變器同時有(you)充(chong)電(dian)功能,省(sheng)掉了后備式UPS的附加充(chong)電(dian)器,其(qi)充(chong)電(dian)能力要比(bi)附加充(chong)電(dian)器強的多,當要求(qiu)長延時供電(dian)時,無(wu)須再增加機外充(chong)電(dian)設備;
·由于逆變器(qi)與輸出直接(jie)接(jie)在一起,沒有(you)轉換開關的限制,所以(yi)輸出功(gong)率可提高到5-10KVA。
為(wei)(wei)了(le)(le)進一步改(gai)善(shan)在(zai)(zai)(zai)線(xian)(xian)互動式(shi)(shi)的(de)(de)功(gong)能(neng)(neng),可(ke)(ke)在(zai)(zai)(zai)輸入(ru)開(kai)關和(he)智能(neng)(neng)調壓之間串(chuan)接一個(ge)電(dian)感,目的(de)(de)在(zai)(zai)(zai)于當(dang)市電(dian)掉電(dian)時(shi)(shi),逆變器可(ke)(ke)立即(ji)向負載供電(dian),因(yin)為(wei)(wei)串(chuan)聯電(dian)感對逆變輸出反饋(kui)到電(dian)網的(de)(de)電(dian)流有很(hen)強的(de)(de)抑制作(zuo)用,避(bi)免了(le)(le)輸入(ru)開(kai)關未斷(duan)開(kai)時(shi)(shi)短路(lu)逆變器輸出的(de)(de)危險,這(zhe)樣做可(ke)(ke)以使在(zai)(zai)(zai)線(xian)(xian)互動式(shi)(shi)的(de)(de)轉(zhuan)換時(shi)(shi)間減小到零,使其完全具備雙逆變在(zai)(zai)(zai)線(xian)(xian)式(shi)(shi)的(de)(de)轉(zhuan)換功(gong)能(neng)(neng),同(tong)時(shi)(shi)還增加了(le)(le)整個(ge)UPS的(de)(de)抗干擾能(neng)(neng)力。但是(shi),這(zhe)樣做卻帶來了(le)(le)降低UPS輸入(ru)功(gong)率因(yin)數(shu)的(de)(de)不良后果。
3、 雙逆變在線式
當前,絕大多數在線(xian)式,特別是(shi)大功(gong)率(lv)在線(xian)式UPS,大都采用了雙逆(ni)變電路(lu)結構。
·逆變(bian)器(qi)(Ⅰ):該逆變(bian)器(qi)為AC-DC單(dan)向逆變(bian),當市電存在時,它完成對電池的充電,并通(tong)過(guo)逆變(bian)器(qi)(Ⅱ)向負載供電,該逆變(bian)器(qi)多為整流或可控整流電路;
·逆(ni)(ni)變器(Ⅱ):該逆(ni)(ni)變器為DC-AC單(dan)向逆(ni)(ni)變,當市電存在時(shi),它由逆(ni)(ni)變(Ⅰ)取得功率后再送到輸出端,并保證向負載(zai)提供高質量的電源;當市電掉(diao)電時(shi),由電池(chi)通過逆(ni)(ni)變器(Ⅱ)向負載(zai)供電;
·旁路開(kai)(kai)關(guan)(guan):平時處在斷(duan)開(kai)(kai)狀態,當逆變電(dian)路發生故(gu)障,或(huo)者當負載有沖擊性(例(li)如啟動負載時)或(huo)故(gu)障過載時,逆變器停止(zhi)輸出,旁路開(kai)(kai)關(guan)(guan)接(jie)(jie)通,由電(dian)網直接(jie)(jie)向負載供電(dian),旁路開(kai)(kai)關(guan)(guan)多為智能型的(de)功率容量很強的(de)無觸點開(kai)(kai)關(guan)(guan)。
雙逆變在線式UPS的性能特點如下:
·因為不管市電有無,負載的(de)全部功率都由(you)逆(ni)變器給(gei)出(chu),所以(yi)可以(yi)向負載提供(gong)高(gao)質量的(de)電源,例(li)如輸出(chu)電壓(ya)穩(wen)定精度(du)、頻率穩(wen)定度(du)、輸出(chu)電壓(ya)動(dong)態響應、波形失真(zhen)度(du)等指標,都是比(bi)較高(gao)的(de);
·市(shi)電(dian)掉電(dian)時,輸(shu)出(chu)電(dian)壓(ya)不受任何影響,沒有轉換時間;
·因為(wei)無論市電有(you)無,全(quan)部負載功(gong)(gong)(gong)率都由逆(ni)變(bian)器供出(chu)(chu)(chu),UPS的(de)(de)功(gong)(gong)(gong)率余量(liang)有(you)限,輸(shu)出(chu)(chu)(chu)能(neng)力不理(li)想,所(suo)以對(dui)負載提(ti)出(chu)(chu)(chu)限制條件,例如輸(shu)出(chu)(chu)(chu)電流峰值系數(shu)(一般(ban)(ban)只(zhi)達到3:1)、過載能(neng)力、輸(shu)出(chu)(chu)(chu)功(gong)(gong)(gong)率因數(shu)(一般(ban)(ban)為(wei)0.8)、輸(shu)出(chu)(chu)(chu)有(you)功(gong)(gong)(gong)功(gong)(gong)(gong)率小于標定(ding)的(de)(de)KVA數(shu),應付沖擊性(xing)負載的(de)(de)能(neng)力等(deng);
·由于逆變器(Ⅰ)多為整流(liu)(liu)電路,對電網形成(cheng)電流(liu)(liu)諧波(bo)(bo)干擾,輸入功率因數(shu)(shu)低(di),經(jing)濾(lv)波(bo)(bo)后,最(zui)小(xiao)的諧波(bo)(bo)電流(liu)(liu)成(cheng)份(fen)在10%左右(you),而輸入功率因數(shu)(shu)只有(you)0.8左右(you),如果(guo)在逆變器(Ⅰ)中使用功率因數(shu)(shu)校正技術,則可把輸入功率因數(shu)(shu)提高到接(jie)近1,輸入電流(liu)(liu)諧波(bo)(bo)成(cheng)份(fen)也會大幅度降低(di);
·在(zai)市電存在(zai)時,由(you)于(yu)兩個逆變器(qi)都承擔100%的(de)(de)負(fu)載功率(lv),所以(yi)整機效(xiao)率(lv)低,10KVA以(yi)下的(de)(de)UPS為80%左右,50 KVA的(de)(de)可(ke)達(da)85-90%,100 KVA以(yi)上(shang)的(de)(de)可(ke)達(da)90--92%。
4、 雙逆變電壓補償在線式
是由美國APC Silcon首先提出(chu)并在三(san)相大功(gong)率UPS中(zhong)形成產品的(de),同(tong)樣是雙逆變(bian)電(dian)(dian)路(lu)結(jie)構(gou),同(tong)樣是在線(xian)工作,但是,由于(yu)它成功(gong)地把交流(liu)穩壓技(ji)術中(zhong)的(de)電(dian)(dian)壓補償原(yuan)理用到了(le)UPS的(de)主(zhu)電(dian)(dian)路(lu)中(zhong),相對(dui)雙逆變(bian)在線(xian)式UPS,Silcon DP300E系列(lie)大功(gong)率UPS在適應電(dian)(dian)網環境(jing)并且不干擾破壞(huai)電(dian)(dian)網、在輸出(chu)能力和可靠(kao)性等多項UPS主(zhu)要指標方面都有了(le)新(xin)的(de)突(tu)破。APC Silcon稱此(ci)電(dian)(dian)路(lu)結(jie)構(gou)為Delta逆變(bian)技(ji)術。
·逆變器(Ⅰ):它是一組DC-AC和AC-DC雙向逆變器,它的輸出變壓器(高 頻)的付邊串聯在UPS主電路中,其功能有三個:
第(di)一:對UPS輸入端進行(xing)輸入功率(lv)因數補償(chang),并抑制輸入電流(liu)諧波(bo);
第二:與(yu)逆(ni)變(Ⅱ)一起(qi),完成(cheng)對輸(shu)(shu)(shu)(shu)(shu)入(ru)電(dian)(dian)壓(ya)(ya)(ya)的補償,當輸(shu)(shu)(shu)(shu)(shu)入(ru)電(dian)(dian)壓(ya)(ya)(ya)高于輸(shu)(shu)(shu)(shu)(shu)出 電(dian)(dian)壓(ya)(ya)(ya)額定(ding)值(zhi)(zhi)時,逆(ni)變器(Ⅰ)吸收功率,反極性補償輸(shu)(shu)(shu)(shu)(shu)入(ru)輸(shu)(shu)(shu)(shu)(shu)出電(dian)(dian)壓(ya)(ya)(ya)的差(cha)值(zhi)(zhi),當輸(shu)(shu)(shu)(shu)(shu)入(ru)電(dian)(dian)壓(ya)(ya)(ya)低于輸(shu)(shu)(shu)(shu)(shu)出電(dian)(dian)壓(ya)(ya)(ya)額定(ding)值(zhi)(zhi)時,逆(ni)變器(Ⅰ)輸(shu)(shu)(shu)(shu)(shu)出功率,正極性補償輸(shu)(shu)(shu)(shu)(shu)入(ru)輸(shu)(shu)(shu)(shu)(shu)出電(dian)(dian)壓(ya)(ya)(ya)的差(cha)值(zhi)(zhi);
第三:與(yu)逆變器(Ⅱ)一起(qi)完成對(dui)電池的(de)充(chong)電和浮充(chong)功能。
·逆變器(Ⅱ):該逆變器同樣是DC-AC和AC-DC雙向逆變器,它的功能有四個:
第一:同逆(ni)變器(Ⅰ)一起(qi),完成對輸入輸出(chu)電壓差值的補償(chang);
第二:同逆變器(qi)(Ⅰ)一起完成(cheng)對(dui)電(dian)池(chi)的充電(dian)和電(dian)壓浮充功能;
第三(san):隨(sui)時(shi)監測輸出(chu)電(dian)(dian)壓(ya),保證(zheng)輸出(chu)電(dian)(dian)壓(ya)的穩定,對輸出(chu)電(dian)(dian)壓(ya)波形失(shi)真和輸出(chu)電(dian)(dian)流諧波成(cheng)份進行補償,使其(qi)不(bu)對電(dian)(dian)網產生影響(xiang);
第四(si):當(dang)市(shi)電(dian)掉(diao)電(dian)時,全(quan)部輸出功率由(you)逆(ni)變器(Ⅱ)給(gei)出,并且保(bao)證輸出電(dian)壓不間(jian)斷,轉換時間(jian)為零。
是雙(shuang)逆(ni)變電壓補償在線式UPS在各種情況下電流和功率傳輸示(shi)意圖(這里假定(ding)UPS效率為(wei)100%)
雙逆變電壓補償在線式的性能特點如下:
因為逆(ni)變器(qi)(Ⅱ)隨時監視(shi)控制輸(shu)出電(dian)壓,并(bing)通過逆(ni)變(Ⅰ)參與主回(hui)路電(dian)壓的(de)(de)調整,所以(yi)不管市電(dian)有(you)無(wu),都可以(yi)向負載提供(gong)高質量的(de)(de)電(dian)源,例(li)如輸(shu)出電(dian)壓穩(wen)定度、頻率穩(wen)定度、輸(shu)出電(dian)壓動態響應、波(bo)形失真等指標,都是比(bi)較高的(de)(de)。
市電(dian)掉(diao)電(dian)時(shi),輸出電(dian)壓不受響應,沒有(you)轉換(huan)時(shi)間。并且,當負載電(dian)流發(fa)生畸變時(shi),也由逆變器(Ⅱ)調整補償掉(diao),所以是(shi)典型的在線工作方式。
當市電存在時,逆變(bian)(bian)器(Ⅰ)和(he)(Ⅱ)只對(dui)輸(shu)(shu)入(ru)(ru)電壓與輸(shu)(shu)出電壓的(de)差值(zhi)進行(xing)調(diao)整和(he)補(bu)償,逆變(bian)(bian)器承擔的(de)最大功(gong)(gong)(gong)(gong)(gong)率(當輸(shu)(shu)入(ru)(ru)電壓處于上限(xian)(xian)和(he)下限(xian)(xian)時)僅為輸(shu)(shu)出功(gong)(gong)(gong)(gong)(gong)率的(de)20%(相(xiang)當于輸(shu)(shu)入(ru)(ru)電壓變(bian)(bian)化范圍),所以(yi)功(gong)(gong)(gong)(gong)(gong)率強度很(hen)小(1/5),功(gong)(gong)(gong)(gong)(gong)率余(yu)量大,這就大大增(zeng)強了(le)UPS的(de)輸(shu)(shu)出能力,與雙(shuang)逆變(bian)(bian)在線式相(xiang)比(bi),過載能力增(zeng)強(200%,1分鐘),不(bu)再(zai)對(dui)負載電流波峰系數予以(yi)限(xian)(xian)制,可從容地(di)對(dui)付沖擊性負載,不(bu)再(zai)對(dui)負載功(gong)(gong)(gong)(gong)(gong)率因(yin)數進行(xing)限(xian)(xian)制,輸(shu)(shu)出有功(gong)(gong)(gong)(gong)(gong)功(gong)(gong)(gong)(gong)(gong)率可以(yi)等于標定的(de)KVA值(zhi)。
·逆(ni)變(bian)器(Ⅰ)同(tong)時完(wan)成了對輸入(ru)端的功(gong)(gong)率(lv)因數校正功(gong)(gong)能,使輸入(ru)功(gong)(gong)率(lv)因數等于1,輸入(ru)諧波電流(liu)降到3%以下(xia)。
在市電存在時,由于兩個逆變器承(cheng)擔的最(zui)大功(gong)率僅為輸出功(gong)率的1/5,所以整(zheng)機效率在很(hen)大的功(gong)率范圍(wei)內(nei)都可達到96%。
在市電存在的情況下(UPS連續運行(xing)時間的99%是(shi)有市電的),逆變器功(gong)率強度(du)僅為(wei)設計(ji)值(逆變器Ⅱ)的1/5,所以(yi)元器件乃(nai)至整(zheng)機的壽(shou)命和可靠性必然大幅度(du)提高。
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