電(dian)(dian)動車(che)充電(dian)(dian)器實際上就是(shi)一(yi)(yi)個開關電(dian)(dian)源加上一(yi)(yi)個檢測電(dian)(dian)路(lu),目前很多電(dian)(dian)動車(che)的48V充電(dian)(dian)器都是(shi)采用KA3842和比較器LM358來完成充電(dian)(dian)工作 

工作原理

   220V交流(liu)電(dian)(dian)(dian)(dian)經(jing)(jing)LF1雙向濾波(bo)(bo).VD1－VD4整流(liu)為(wei)脈(mo)(mo)(mo)動直流(liu)電(dian)(dian)(dian)(dian)壓(ya)(ya),再經(jing)(jing)C3濾波(bo)(bo)后形成(cheng)約300V的(de)直流(liu)電(dian)(dian)(dian)(dian)壓(ya)(ya),300V直流(liu)電(dian)(dian)(dian)(dian)壓(ya)(ya)經(jing)(jing)過啟動電(dian)(dian)(dian)(dian)阻R4為(wei)脈(mo)(mo)(mo)寬調制集成(cheng)電(dian)(dian)(dian)(dian)路IC1的(de)7腳(jiao)(jiao)提供(gong)(gong)啟動電(dian)(dian)(dian)(dian)壓(ya)(ya),IC1的(de)7腳(jiao)(jiao)得到啟動電(dian)(dian)(dian)(dian)壓(ya)(ya)后,(7腳(jiao)(jiao)電(dian)(dian)(dian)(dian)壓(ya)(ya)高于(yu)14V時,集成(cheng)電(dian)(dian)(dian)(dian)路開(kai)始工作(zuo)),6腳(jiao)(jiao)輸出(chu)PWM脈(mo)(mo)(mo)沖,驅動電(dian)(dian)(dian)(dian)源(yuan)開(kai)關管(場效(xiao)應管)VT7工作(zuo)在開(kai)關狀態,電(dian)(dian)(dian)(dian)流(liu)通過VT1的(de)S極-D極-R7-接地端.此(ci)時開(kai)關變壓(ya)(ya)器T1的(de)8-9繞(rao)組產(chan)生感應電(dian)(dian)(dian)(dian)壓(ya)(ya),經(jing)(jing)VD6，R2為(wei)IC1的(de)7腳(jiao)(jiao)提供(gong)(gong)穩定的(de)工作(zuo)電(dian)(dian)(dian)(dian)壓(ya)(ya)，4腳(jiao)(jiao)外接振蕩(dang)電(dian)(dian)(dian)(dian)阻R10和振蕩(dang)電(dian)(dian)(dian)(dian)容C7決定IC1的(de)振蕩(dang)頻率,

   IC2(TL431)為精密基準電(dian)(dian)壓(ya)源(yuan),IC4(光耦合器(qi)4N35)配合用來穩定充電(dian)(dian)電(dian)(dian)壓(ya),調(diao)整RP1(510歐半(ban)可(ke)調(diao)電(dian)(dian)位器(qi))可(ke)以細調(diao)充電(dian)(dian)器(qi)的電(dian)(dian)壓(ya),LED1是(shi)電(dian)(dian)源(yuan)指(zhi)(zhi)示(shi)燈.接通電(dian)(dian)源(yuan)后該指(zhi)(zhi)示(shi)燈就會發出紅色的光。

   VT1開始工(gong)作后(hou),變壓器的(de)(de)(de)次級6-5繞(rao)組輸出的(de)(de)(de)電(dian)壓經快速恢復二(er)極(ji)(ji)管VD60整(zheng)流(liu),C18濾波得到穩(wen)定的(de)(de)(de)電(dian)壓(約53V).此電(dian)壓一(yi)路經二(er)極(ji)(ji)管VD70(該二(er)極(ji)(ji)管起(qi)防止電(dian)池(chi)的(de)(de)(de)電(dian)流(liu)倒灌給充電(dian)器的(de)(de)(de)作用(yong))給電(dian)池(chi)充電(dian),另一(yi)路經限流(liu)電(dian)阻R38,穩(wen)壓二(er)極(ji)(ji)管VZD1,濾波電(dian)容C60,為(wei)比較器IC3(LM358)提(ti)供12V工(gong)作電(dian)源,VD12為(wei)IC3提(ti)供基準電(dian)壓,經R25,R26,R27分壓后(hou)送(song)到IC3的(de)(de)(de)2腳和(he)5腳。

   正常充電(dian)(dian)時，R33上端有0.18－0.2V的(de)電(dian)(dian)壓，此(ci)電(dian)(dian)壓經R10加到(dao)IC3的(de)3腳，從1腳輸(shu)(shu)出高電(dian)(dian)平。1腳輸(shu)(shu)出的(de)高電(dian)(dian)平信號分(fen)三路(lu)輸(shu)(shu)出，第(di)一路(lu)驅動(dong)VT2導通，散(san)熱(re)風扇得電(dian)(dian)開始工作，第(di)二(er)路(lu)經過(guo)電(dian)(dian)阻R34點亮雙色(se)二(er)極(ji)管(guan)(guan)LED2中(zhong)(zhong)的(de)紅色(se)發光(guang)二(er)極(ji)管(guan)(guan)，第(di)三路(lu)輸(shu)(shu)入到(dao)IC3的(de)6腳，此(ci)時7腳輸(shu)(shu)出低電(dian)(dian)平，雙色(se)發光(guang)二(er)極(ji)管(guan)(guan)LED2中(zhong)(zhong)的(de)綠色(se)發光(guang)二(er)極(ji)管(guan)(guan)熄(xi)滅(mie)，充電(dian)(dian)器進入恒流(liu)充電(dian)(dian)階段。

   當電池電壓升到44.2V左右時，充電器進(jin)入恒(heng)壓(ya)充(chong)電(dian)(dian)(dian)階(jie)段(duan)，電(dian)(dian)(dian)流逐漸(jian)減小(xiao)。當充(chong)電(dian)(dian)(dian)電(dian)(dian)(dian)流減小(xiao)到200MA－300MA時，R33上端的(de)電(dian)(dian)(dian)壓(ya)下降，IC3的(de)3腳(jiao)電(dian)(dian)(dian)壓(ya)低(di)于2腳(jiao)，1腳(jiao)輸出(chu)低(di)電(dian)(dian)(dian)平(ping)，雙色(se)發(fa)光(guang)(guang)二極(ji)管(guan)LED2中(zhong)的(de)紅色(se)發(fa)光(guang)(guang)二極(ji)管(guan)熄滅，三極(ji)管(guan)VT2截止，風扇(shan)停止運轉，同時IC3的(de)7腳(jiao)輸出(chu)高電(dian)(dian)(dian)平(ping)，此高電(dian)(dian)(dian)平(ping)一(yi)路經(jing)過電(dian)(dian)(dian)阻R35點(dian)亮雙色(se)發(fa)光(guang)(guang)二極(ji)管(guan)LED2中(zhong)的(de)綠色(se)發(fa)光(guang)(guang)二極(ji)管(guan)（指(zhi)示電(dian)(dian)(dian)瓶已經(jing)充(chong)滿，此時并沒有真正充(chong)滿，實(shi)際上還得一(yi)兩小(xiao)時才能真正充(chong)滿），另(ling)一(yi)路經(jing)R52，VD18,R40,RP2到達(da)IC2的(de)1腳(jiao)，使(shi)輸出(chu)電(dian)(dian)(dian)壓(ya)降低(di)，充(chong)電(dian)(dian)(dian)器進(jin)入200MA-300MA的(de)涓流充(chong)電(dian)(dian)(dian)階(jie)段(duan)（浮充(chong)），改變RP2的(de)電(dian)(dian)(dian)阻值可以調整充(chong)電(dian)(dian)(dian)器由恒(heng)流充(chong)電(dian)(dian)(dian)狀態轉到涓流充(chong)電(dian)(dian)(dian)狀態的(de)轉折(zhe)電(dian)(dian)(dian)流（200－300MA）。

常見故障

   這種類型電(dian)動車充(chong)電(dian)器的常(chang)見故障有下面幾(ji)種情(qing)況：

1、高壓(ya)電(dian)路故障(zhang)：該部分電(dian)路出現(xian)問(wen)題(ti)的主要(yao)現(xian)象是(shi)指示燈(deng)不(bu)(bu)亮。通常(chang)還(huan)伴(ban)有保險絲燒(shao)(shao)斷，此(ci)時應檢查整流二(er)極管(guan)VD1-VD4是(shi)否擊穿(chuan)，電(dian)容C3是(shi)否炸裂(lie)或者(zhe)(zhe)鼓包，VT2是(shi)否擊穿(chuan)，R7,R4是(shi)否開(kai)路，此(ci)時更換損壞(huai)的元件(jian)即(ji)可排(pai)除故障(zhang)，若經(jing)常(chang)燒(shao)(shao)VT1,且VT1不(bu)(bu)燙(tang)手，則應重點檢查R1,C4,VD5等元器件(jian)，若VT1燙(tang)手，則重點檢查開(kai)關變壓(ya)器次級電(dian)路中的元器件(jian)有無短路或者(zhe)(zhe)漏電(dian)。

   若(ruo)紅色(se)指示燈閃爍，則故障多數(shu)是由R2或者VD6開路(lu)，變(bian)壓器(qi)T1線腳虛焊引起。

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（充電器注明不(bu)可隨車攜帶就是怕RP2因振動(dong)而改(gai)變阻(zu)值），就會導致(zhi)輸出(chu)(chu)電(dian)(dian)壓漂移。若輸出(chu)(chu)電(dian)(dian)壓偏高，電(dian)(dian)瓶會過(guo)充，嚴重(zhong)時會失水－發燙，最終導致(zhi)充爆(bao)，若輸出(chu)(chu)電(dian)(dian)壓偏低，會導致(zhi)電(dian)(dian)瓶欠(qian)充，縮短其壽命。