電(dian)平(ping)檢(jian)測(ce)器(qi)也(ye)可(ke)以(yi)設(she)計(ji)成(cheng)用(yong)同(tong)相(xiang)端(duan)作(zuo)輸(shu)入(ru)測(ce)定(ding)端(duan)，而(er)將(qiang)參(shen)考(kao)基(ji)準(zhun)電(dian)壓(ya)加(jia)到(dao)反(fan)相(xiang)輸(shu)入(ru)端(duan)的(di)電(dian)路(lu)型(xing)式(shi)。這(zhe)時(shi)與(yu)，上(shang)麵(mian)所(suo)討(tao)論(lun)的(di)檢(jian)測(ce)器(qi)相(xiang)比(bi),輸(shu)出(chu)電(dian)壓(ya)的(di)極(ji)性(xing)剛(gang)好(hao)相(xiang)反(fan)。
具(ju)有(you)滯(zhi)後(hou)特(te)性(xing)的(di)電(dian)壓(ya)比(bi)較(jiao)器(qi)
中(zhong)、小(xiao)型(xing)後(hou)備(bei)式(shi)UPS在(zai)進(jin)行(hang)市(shi)電(dian)供(gong)電(dian)與(yu)逆(ni)變(bian)器(qi)供(gong)電(dian)之(zhi)間(jian)相(xiang)互(hu)轉(zhuan)換(huan)控(kong)製(zhi)過(guo)程(cheng)中(zhong),如(ru)果(guo)市(shi)電(dian)供(gong)電(dian)並(bing)未(wei)中(zhong)斷(duan),但(dan)是(shi)由(you)於(yu)某(mou)種(zhong)突(tu)發(fa)原(yuan)因(yin)(如(ru)大(dai)負(fu)載(zai)突(tu)然(ran)並(bing)入(ru)電(dian)網(wang))使(shi)電(dian)網(wang)電(dian)壓(ya)下(xia)降(xiang)時(shi), UPS將(qiang)自(zi)動(dong)地(de)把(ba)對(dui)負(fu)載(zai)的(di)供(gong)電(dian)從(zong)市(shi)電(dian)供(gong)電(dian)轉(zhuan)換(huan)到(dao)由(you)蓄(xu)電(dian)池(chi)支(zhi)持(chi)的(di)逆(ni)變(bian)器(qi)供(gong)電(dian)狀(zhuang)態(tai)(目(mu)前(qian)一(yi)般(pan)UPS的(di)電(dian)壓(ya)轉(zhuan)換(huan)點(dian)定(ding)在(zai)170V左(zuo)右(you))。如(ru)果(guo)在(zai)對(dui)輸(shu)入(ru)交(jiao)流(liu)電(dian)壓(ya)進(jin)行(hang)電(dian)平(ping)檢(jian)測(ce)時(shi)，在(zai)控(kong)製(zhi)線(xian)路(lu)中(zhong)采(cai)用(yong)一(yi)-般(pan)性(xing)能(neng)的(di)電(dian)壓(ya)比(bi)較(jiao)器(qi),假(jia)若(ruo)又(you)遇(yu)到(dao)市(shi)電(dian)電(dian)壓(ya)下(xia)降(xiang)到(dao)UPS電(dian)源(yuan)的(di)自(zi)動(dong)轉(zhuan)換(huan)切(qie)換(huan)點(dian)附(fu)近(jin)時(shi),就(jiu)有(you)可(ke)能(neng)產(chan)生(sheng)UPS在(zai)市(shi)電(dian)供(gong)電(dian)與(yu)逆(ni)變(bian)器(qi)供(gong)電(dian)之(zhi)間(jian)進(jin)行(hang)不(bu)正(zheng)常(chang)的(di)頻(pin)繁(fan)切(qie)換(huan)的(di)問(wen)題(ti),這(zhe)種(zhong)頻(pin)繁(fan)的(di)切(qie)換(huan)運(yun)行(hang)會(kuai)造(zao)成(cheng)對(dui)後(hou)級(ji)負(fu)載(zai)供(gong)電(dian)的(di)嚴(yan)重(chong)幹(gan)擾(rao)。為(wei)了(liao)避(bi)免(wen)這(zhe)個(ge)問(wen)題(ti)產(chan)生(sheng),一(yi)般(pan)在(zai)UPS電(dian)源(yuan)設(she)計(ji)中(zhong)都(du)采(cai)用(yong)當(dang)市(shi)電(dian)電(dian)網(wang)電(dian)壓(ya)從(zong)220V下(xia)降(xiang)到(dao)170V時(shi), UPS電(dian)源(yuan)自(zi)動(dong)地(de)從(zong)市(shi)電(dian)供(gong)電(dian)轉(zhuan)換(huan)到(dao)由(you)逆(ni)變(bian)器(qi)供(gong)電(dian),但(dan)當(dang)電(dian)網(wang)電(dian)壓(ya)由(you)低(di)變(bian)高(gao)並(bing).上(shang)升(sheng)到(dao)170V時(shi),讓(rang)UPS電(dian)源(yuan)仍(reng)然(ran)處(chu)於(yu)逆(ni)變(bian)器(qi)供(gong)電(dian)狀(zhuang)態(tai),即(ji)不(bu)產(chan)生(sheng)由(you)逆(ni)變(bian)器(qi)供(gong)電(dian)到(dao)市(shi)電(dian)供(gong)電(dian)的(di)任(ren)何(he)轉(zhuan)換(huan)動(dong)作(zuo),隻(zhi)有(you)當(dang)電(dian)網(wang)電(dian)壓(ya)上(shang)升(sheng)到(dao)180~ 185V時(shi), UPS電(dian)源(yuan)才(cai)重(chong)新(xin)恢(hui)複(fu)由(you)市(shi)電(dian)供(gong)電(dian)。能(neng)完(wan)成(cheng)上(shang)述(shu)轉(zhuan)換(huan)功(gong)能(neng)的(di)比(bi)較(jiao)器(qi)有(you)雙(shuang)極(ji)限(xian)電(dian)壓(ya)比(bi)較(jiao)器(qi)和(hu)帶(dai)滯(zhi)後(hou)特(te)性(xing)的(di)電(dian)壓(ya)比(bi)較(jiao)器(qi)。
雙(shuang)極(ji)限(xian)電(dian)壓(ya)比(bi)較(jiao)器(qi)如(ru)圖(tu)1-4所(suo)示(shi),被(bei)檢(jian)測(ce)的(di)正(zheng)弦(xian)波(bo)信(xin)號(hao)被(bei)同(tong)時(shi)送(song)到(dao)運(yun)算(suan)放(fang)大(dai)器(qi)IC1的(di)反(fan)相(xiang)輸(shu)入(ru)端(duan)和(hu)運(yun)算(suan)放(fang)大(dai)器(qi)IC2的(di)同(tong)相(xiang)輸(shu)入(ru)端(duan)。將(qiang)基(ji)準(zhun)電(dian)壓(ya)V送(song)到(dao)運(yun)算(suan)放(fang)大(dai)器(qi)IC1的(di)同(tong)相(xiang)端(duan),基(ji)準(zhun)電(dian)壓(ya)Vq被(bei)送(song)到(dao)運(yun)算(suan)放(fang)大(dai)器(qi)IC的(di)反(fan)相(xiang)端(duan)。若(ruo)電(dian)壓(ya)V2> V1 ,對(dui)運(yun)算(suan)放(fang)大(dai)器(qi)IC1來(lai)說(shui),在(zai)t1到(dao)t4期(qi)間(jian),送(song)到(dao)反(fan)相(xiang)端(duan)的(di)正(zheng)弦(xian)波(bo)電(dian)壓(ya)值(zhi)比(bi)加(jia)在(zai)同(tong)相(xiang)端(duan)的(di)基(ji)準(zhun)電(dian)壓(ya)Vz低(di),所(suo)以(yi)在(zai)運(yun)算(suan)放(fang)大(dai)器(qi)IC1的(di)輸(shu)出(chu)端(duan)將(qiang)輸(shu)出(chu)正(zheng)飽(bao)和(hu)電(dian)壓(ya)V3。同(tong)理(li),對(dui)運(yun)算(suan)放(fang)大(dai)器(qi)IC2來(lai)說(shui),在(zai)0到(dao)tz和(hu)t3到(dao)tg期(qi)間(jian),送(song)到(dao)同(tong)相(xiang)端(duan)的(di)正(zheng)弦(xian)波(bo)電(dian)壓(ya)值(zhi)比(bi)反(fan)相(xiang)端(duan)的(di)基(ji)準(zhun)電(dian)壓(ya)V高(gao),因(yin)此(ci),在(zai)運(yun)算(suan)放(fang)大(dai)器(qi)IC2的(di)輸(shu)出(chu)端(duan)將(qiang)同(tong)樣(yang)有(you)正(zheng)飽(bao)和(hu)電(dian)壓(ya)V4輸(shu)出(chu)。來(lai)自(zi)運(yun)算(suan)放(fang)大(dai)器(qi)IC1的(di)電(dian)壓(ya)V3和(hu)來(lai)自(zi)運(yun)算(suan)放(fang)大(dai)器(qi)IC2的(di)電(dian)壓(ya)V4 ,經(jing)由(you)二(er)極(ji)管(guan)VD1和(hu)VD2組(zu)成(cheng)的(di)與(yu)門(men)輸(shu)出(chu),得(dei)到(dao)一(yi)-串(chuan)脈(mo)衝(chong)寬(kuan)度(duo)為(wei)tz~t, t4~t3, t-…的(di)正(zheng)脈(mo)衝(chong)。這(zhe)樣(yang)一(yi)串(chuan)脈(mo)衝(chong)僅(jin)在(zai)正(zheng)弦(xian)波(bo)電(dian)壓(ya)大(dai)於(yu)基(ji)準(zhun)電(dian)壓(ya)V1、小(xiao)於(yu)基(ji)準(zhun)電(dian)壓(ya)V2時(shi)才(cai)出(chu)現(xian),從(zong)而(er)構(gou)成(cheng)所(suo)謂(wei)的(di)雙(shuang)極(ji)限(xian)電(dian)壓(ya)比(bi)較(jiao)器(qi)。有(you)了(liao)雙(shuang)極(ji)限(xian)電(dian)壓(ya)比(bi)較(jiao)器(qi)後(hou),就(jiu)可(ke)對(dui)市(shi)電(dian)電(dian)網(wang)進(jin)行(hang)瞬(shun)時(shi)的(di)電(dian)平(ping)檢(jian)測(ce)。這(zhe)是(shi)UPS電(dian)源(yuan)能(neng)對(dui)市(shi)電(dian)電(dian)壓(ya)變(bian)化(hua)產(chan)生(sheng)快(kuai)速(su)反(fan)應(ying)的(di)重(chong)要(yao)基(ji)礎(chu)。
另(ling)外(wai)一(yi)種(zhong)特(te)殊(shu)電(dian)壓(ya)比(bi)較(jiao)器(qi)是(shi)所(suo)謂(wei)具(ju)有(you)滯(zhi)後(hou)特(te)性(xing)的(di)比(bi)較(jiao)器(qi)。這(zhe)種(zhong)比(bi)較(jiao)器(qi)的(di)參(shen)考(kao)基(ji)準(zhun)比(bi)較(jiao)電(dian)平(ping)是(shi)隨(sui)比(bi)較(jiao)器(qi)的(di)輸(shu)入(ru)電(dian)平(ping)變(bian)化(hua)方(fang)向(xiang)的(di)不(bu)同(tong)而(er)有(you)所(suo)改(gai)變(bian)的(di),它(ta)的(di)輸(shu)入(ru)和(hu)輸(shu)出(chu)電(dian)壓(ya)變(bian)化(hua)關(guan)係(ji)如(ru)圖(tu)1-5( a )所(suo)示(shi)。
當(dang)輸(shu)入(ru)電(dian)壓(ya)V;從(zong)零(ling)上(shang)升(sheng)至(zhi)電(dian)壓(ya)V時(shi),比(bi)較(jiao)器(qi)的(di)電(dian)壓(ya)輸(shu)出(chu)將(qiang)從(zong)高(gao)電(dian)平(ping)V。下(xia)降(xiang)至(zhi)低(di)電(dian)平(ping)0V。如(ru)繼(ji)續(xu)增(zeng)大(dai)輸(shu)入(ru)電(dian)壓(ya)V,比(bi)較(jiao)器(qi)的(di)輸(shu)出(chu)將(qiang)一(yi)直(zhi)維(wei)持(chi)在(zai)低(di)電(dian)平(ping)狀(zhuang)態(tai)。相(xiang)反(fan),假(jia)如(ru)降(xiang)低(di)輸(shu)入(ru)電(dian)壓(ya)V,當(dang)輸(shu)入(ru)電(dian)壓(ya)V;下(xia)降(xiang)到(dao)V;= V時(shi)，比(bi)較(jiao)器(qi)的(di)電(dian)壓(ya)輸(shu)出(chu)並(bing)不(bu)會(kuai).上(shang)升(sheng)到(dao)高(gao)電(dian)平(ping)V。這(zhe)一(yi)點(dian)是(shi)明(ming)顯(xian)區(ou)別(bie)於(yu)一(yi)般(pan)電(dian)壓(ya)比(bi)較(jiao)器(qi)的(di)特(te)殊(shu)功(gong)能(neng)。隻(zhi)有(you)當(dang)輸(shu)入(ru)電(dian)壓(ya)V下(xia)降(xiang)到(dao)Vz時(shi),比(bi)較(jiao)器(qi)的(di)電(dian)壓(ya)輸(shu)出(chu)才(cai)重(chong)新(xin)返(fan)回(hui)到(dao)高(gao)電(dian)平(ping)V。即(ji)比(bi)較(jiao)器(qi)輸(shu)入(ru)電(dian)壓(ya)的(di)上(shang)升(sheng)轉(zhuan)換(huan)點(dian)和(hu)下(xia)降(xiang)轉(zhuan)換(huan)點(dian)之(zhi)間(jian)有(you)一(yi)個(ge)電(dian)壓(ya)差(chai),這(zhe)樣(yang)在(zai)輸(shu)入(ru)電(dian)壓(ya)和(hu)輸(shu)出(chu)電(dian)壓(ya)變(bian)化(hua)之(zhi)間(jian)形(xing)成(cheng)所(suo)謂(wei)的(di)滯(zhi)後(hou)特(te)性(xing)。
能(neng)實(shi)現(xian)帶(dai)滯(zhi)後(hou)特(te)性(xing)的(di)電(dian)壓(ya)比(bi)較(jiao)器(qi)的(di)工(gong)作(zuo)原(yuan)理(li)如(ru)圖(tu)1-5( b)所(suo)示(shi)。由(you)電(dian)源(yuan)+ V、電(dian)阻(zu)R,和(hu)穩(wen)壓(ya)二(er)極(ji)管(guan)所(suo)組(zu)成(cheng)的(di)穩(wen)壓(ya)線(xian)路(lu)產(chan)生(sheng)一(yi)個(ge)參(shen)考(kao)基(ji)準(zhun)電(dian)壓(ya)Vz。 電(dian)壓(ya)Vz被(bei)送(song)到(dao)此(ci)較(jiao)器(qi)的(di)同(tong)相(xiang)輸(shu)入(ru)端(duan)。被(bei)測(ce)信(xin)號(hao)Vg經(jing)電(dian)阻(zu)R1和(hu)Rj及(ji)電(dian)位(wei)器(qi)Rz分(fen)壓(ya)後(hou)再(zai)經(jing)電(dian)阻(zu)R5被(bei)送(song)到(dao)比(bi)較(jiao)器(qi)的(di)反(fan)相(xiang)輸(shu)入(ru)端(duan)。這(zhe)樣(yang)一(yi)來(lai),就(jiu)在(zai)比(bi)較(jiao)器(qi)的(di)反(fan)相(xiang)端(duan)輸(shu)入(ru)一(yi)個(ge)V控(kong)製(zhi)信(xin)號(hao)。當(dang)輸(shu)入(ru)信(xin)號(hao)V;<Vz時(shi),比(bi)較(jiao)器(qi)的(di)電(dian)壓(ya)輸(shu)出(chu)Vout=V。( 12V的(di)高(gao)電(dian)平(ping)) , 這(zhe)時(shi)二(er)極(ji)管(guan)VD導(dao)通(tong)。一(yi)旦(dan)二(er)極(ji)管(guan)VD導(dao)通(tong),比(bi)較(jiao)器(qi)的(di)同(tong)相(xiang)輸(shu)入(ru)端(duan)的(di)參(shen)考(kao)基(ji)準(zhun)電(dian)壓(ya)將(qiang)從(zong)電(dian)壓(ya)Vz上(shang)升(sheng)到(dao)Vx :
