電(dian)動車(che)充(chong)電(dian)器(qi)實際上(shang)(shang)就是一(yi)個開(kai)關電(dian)源加上(shang)(shang)一(yi)個檢(jian)測電(dian)路,目前很多電(dian)動車(che)的48V充(chong)電(dian)器(qi)都(dou)是采用KA3842和比較器(qi)LM358來完成(cheng)充(chong)電(dian)工作 

工作原理

   220V交流電(dian)經LF1雙向濾(lv)波(bo).VD1－VD4整流為脈動(dong)直流電(dian)壓,再經C3濾(lv)波(bo)后(hou)形(xing)成約300V的直流電(dian)壓,300V直流電(dian)壓經過(guo)(guo)啟(qi)動(dong)電(dian)阻R4為脈寬調制(zhi)集成電(dian)路(lu)(lu)IC1的7腳提(ti)供啟(qi)動(dong)電(dian)壓,IC1的7腳得到啟(qi)動(dong)電(dian)壓后(hou),(7腳電(dian)壓高于14V時,集成電(dian)路(lu)(lu)開(kai)(kai)始工作(zuo)),6腳輸出PWM脈沖,驅動(dong)電(dian)源開(kai)(kai)關管(場效應(ying)管)VT7工作(zuo)在開(kai)(kai)關狀態,電(dian)流通(tong)過(guo)(guo)VT1的S極(ji)-D極(ji)-R7-接地端.此時開(kai)(kai)關變壓器T1的8-9繞組產生(sheng)感(gan)應(ying)電(dian)壓,經VD6，R2為IC1的7腳提(ti)供穩定的工作(zuo)電(dian)壓，4腳外接振(zhen)(zhen)蕩(dang)電(dian)阻R10和振(zhen)(zhen)蕩(dang)電(dian)容(rong)C7決定IC1的振(zhen)(zhen)蕩(dang)頻率(lv),

   IC2(TL431)為精密基準電(dian)(dian)壓(ya)源(yuan),IC4(光(guang)(guang)耦合(he)(he)器4N35)配合(he)(he)用來穩定(ding)充(chong)電(dian)(dian)電(dian)(dian)壓(ya),調(diao)整(zheng)RP1(510歐半可調(diao)電(dian)(dian)位(wei)器)可以細調(diao)充(chong)電(dian)(dian)器的(de)電(dian)(dian)壓(ya),LED1是電(dian)(dian)源(yuan)指示(shi)燈(deng).接通電(dian)(dian)源(yuan)后該指示(shi)燈(deng)就會發出(chu)紅色(se)的(de)光(guang)(guang)。

   VT1開始工作后(hou),變壓(ya)器(qi)的次(ci)級(ji)6-5繞組(zu)輸出的電(dian)(dian)壓(ya)經快(kuai)速(su)恢復二(er)(er)極(ji)管(guan)VD60整流(liu),C18濾(lv)(lv)波得到穩定(ding)的電(dian)(dian)壓(ya)(約(yue)53V).此電(dian)(dian)壓(ya)一路經二(er)(er)極(ji)管(guan)VD70(該(gai)二(er)(er)極(ji)管(guan)起防止(zhi)電(dian)(dian)池(chi)的電(dian)(dian)流(liu)倒灌給充電(dian)(dian)器(qi)的作用(yong))給電(dian)(dian)池(chi)充電(dian)(dian),另(ling)一路經限(xian)流(liu)電(dian)(dian)阻R38,穩壓(ya)二(er)(er)極(ji)管(guan)VZD1,濾(lv)(lv)波電(dian)(dian)容(rong)C60,為(wei)比較(jiao)器(qi)IC3(LM358)提供12V工作電(dian)(dian)源(yuan),VD12為(wei)IC3提供基準電(dian)(dian)壓(ya),經R25,R26,R27分壓(ya)后(hou)送到IC3的2腳和5腳。

   正(zheng)常充(chong)電(dian)(dian)(dian)時，R33上端有0.18－0.2V的(de)(de)電(dian)(dian)(dian)壓，此電(dian)(dian)(dian)壓經R10加到(dao)IC3的(de)(de)3腳(jiao)，從1腳(jiao)輸出(chu)高電(dian)(dian)(dian)平(ping)(ping)。1腳(jiao)輸出(chu)的(de)(de)高電(dian)(dian)(dian)平(ping)(ping)信號分三路輸出(chu)，第(di)一路驅動VT2導通，散熱(re)風扇得電(dian)(dian)(dian)開始工作(zuo)，第(di)二路經過電(dian)(dian)(dian)阻R34點亮雙色(se)二極(ji)管LED2中的(de)(de)紅色(se)發(fa)光(guang)二極(ji)管，第(di)三路輸入到(dao)IC3的(de)(de)6腳(jiao)，此時7腳(jiao)輸出(chu)低電(dian)(dian)(dian)平(ping)(ping)，雙色(se)發(fa)光(guang)二極(ji)管LED2中的(de)(de)綠(lv)色(se)發(fa)光(guang)二極(ji)管熄(xi)滅，充(chong)電(dian)(dian)(dian)器(qi)進入恒(heng)流充(chong)電(dian)(dian)(dian)階段。

   當電池電壓升到44.2V左右時，充電器進(jin)入恒壓(ya)充(chong)電(dian)(dian)(dian)(dian)階段，電(dian)(dian)(dian)(dian)流(liu)逐(zhu)漸減(jian)小。當(dang)充(chong)電(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)流(liu)減(jian)小到200MA－300MA時(shi)，R33上端的(de)(de)電(dian)(dian)(dian)(dian)壓(ya)下(xia)降，IC3的(de)(de)3腳(jiao)電(dian)(dian)(dian)(dian)壓(ya)低(di)于2腳(jiao)，1腳(jiao)輸出低(di)電(dian)(dian)(dian)(dian)平，雙色發光二極(ji)管(guan)LED2中(zhong)的(de)(de)紅色發光二極(ji)管(guan)熄滅，三極(ji)管(guan)VT2截止，風扇停止運(yun)轉，同時(shi)IC3的(de)(de)7腳(jiao)輸出高電(dian)(dian)(dian)(dian)平，此高電(dian)(dian)(dian)(dian)平一(yi)路(lu)經過(guo)電(dian)(dian)(dian)(dian)阻(zu)R35點亮雙色發光二極(ji)管(guan)LED2中(zhong)的(de)(de)綠色發光二極(ji)管(guan)（指示電(dian)(dian)(dian)(dian)瓶(ping)已經充(chong)滿，此時(shi)并沒有真正(zheng)充(chong)滿，實際上還得(de)一(yi)兩(liang)小時(shi)才能真正(zheng)充(chong)滿），另一(yi)路(lu)經R52，VD18,R40,RP2到達IC2的(de)(de)1腳(jiao)，使輸出電(dian)(dian)(dian)(dian)壓(ya)降低(di)，充(chong)電(dian)(dian)(dian)(dian)器進(jin)入200MA-300MA的(de)(de)涓流(liu)充(chong)電(dian)(dian)(dian)(dian)階段（浮(fu)充(chong)），改變RP2的(de)(de)電(dian)(dian)(dian)(dian)阻(zu)值可以調(diao)整(zheng)充(chong)電(dian)(dian)(dian)(dian)器由恒流(liu)充(chong)電(dian)(dian)(dian)(dian)狀(zhuang)態轉到涓流(liu)充(chong)電(dian)(dian)(dian)(dian)狀(zhuang)態的(de)(de)轉折電(dian)(dian)(dian)(dian)流(liu)（200－300MA）。

常見故障

   這種(zhong)類型電(dian)動車充(chong)電(dian)器(qi)的常見(jian)故障有下面幾種(zhong)情(qing)況：

1、高壓電(dian)路故障：該(gai)部(bu)分電(dian)路出(chu)現問題的(de)主要現象是(shi)指示燈不亮。通(tong)常(chang)(chang)還伴有(you)保險(xian)絲燒(shao)斷，此時(shi)應檢查整(zheng)流二極管(guan)VD1-VD4是(shi)否(fou)擊穿，電(dian)容C3是(shi)否(fou)炸(zha)裂(lie)或者鼓包，VT2是(shi)否(fou)擊穿，R7,R4是(shi)否(fou)開路，此時(shi)更換損(sun)壞的(de)元件即(ji)可排除故障，若經常(chang)(chang)燒(shao)VT1,且VT1不燙(tang)手，則(ze)應重點檢查R1,C4,VD5等元器(qi)件，若VT1燙(tang)手，則(ze)重點檢查開關變壓器(qi)次(ci)級電(dian)路中的(de)元器(qi)件有(you)無短路或者漏電(dian)。

   若紅色指示燈(deng)閃爍，則(ze)故(gu)障多數是由R2或者VD6開路(lu)，變壓(ya)器T1線腳虛(xu)焊(han)引起(qi)。

2、低壓電路故障：低壓電路中最常見的故障就是電流檢測電阻R33燒斷，此時的故障現象是紅燈一直亮，綠燈不亮，輸出電壓低，電瓶始終充不進電，另外，若RP2接觸不良或者因振動導致阻值變化（充電器注明(ming)不可隨車攜帶就是怕RP2因振動而改變阻值），就會(hui)導(dao)(dao)致(zhi)輸出電壓(ya)漂移。若輸出電壓(ya)偏高，電瓶(ping)會(hui)過充(chong)，嚴重時會(hui)失水－發燙，最終導(dao)(dao)致(zhi)充(chong)爆(bao)，若輸出電壓(ya)偏低(di)，會(hui)導(dao)(dao)致(zhi)電瓶(ping)欠充(chong)，縮短(duan)其壽命。