電(dian)動(dong)車充(chong)(chong)電(dian)器實際上就是一(yi)個(ge)開關電(dian)源加上一(yi)個(ge)檢(jian)測電(dian)路,目前很多(duo)電(dian)動(dong)車的48V充(chong)(chong)電(dian)器都(dou)是采用KA3842和(he)比較器LM358來完成充(chong)(chong)電(dian)工作 

工作原理

   220V交流電(dian)經LF1雙向濾波(bo).VD1－VD4整流為脈動直流電(dian)壓(ya)(ya)(ya),再經C3濾波(bo)后形成約300V的(de)(de)直流電(dian)壓(ya)(ya)(ya),300V直流電(dian)壓(ya)(ya)(ya)經過啟(qi)動電(dian)阻R4為脈寬調(diao)制(zhi)集成電(dian)路(lu)(lu)IC1的(de)(de)7腳(jiao)(jiao)提(ti)供啟(qi)動電(dian)壓(ya)(ya)(ya),IC1的(de)(de)7腳(jiao)(jiao)得到(dao)啟(qi)動電(dian)壓(ya)(ya)(ya)后,(7腳(jiao)(jiao)電(dian)壓(ya)(ya)(ya)高于14V時,集成電(dian)路(lu)(lu)開(kai)(kai)始工(gong)作),6腳(jiao)(jiao)輸出PWM脈沖,驅動電(dian)源開(kai)(kai)關(guan)管(guan)(guan)(場效應管(guan)(guan))VT7工(gong)作在開(kai)(kai)關(guan)狀態(tai),電(dian)流通過VT1的(de)(de)S極-D極-R7-接(jie)地端(duan).此時開(kai)(kai)關(guan)變(bian)壓(ya)(ya)(ya)器(qi)T1的(de)(de)8-9繞組(zu)產生感應電(dian)壓(ya)(ya)(ya),經VD6，R2為IC1的(de)(de)7腳(jiao)(jiao)提(ti)供穩(wen)定(ding)的(de)(de)工(gong)作電(dian)壓(ya)(ya)(ya)，4腳(jiao)(jiao)外接(jie)振(zhen)(zhen)蕩(dang)(dang)電(dian)阻R10和振(zhen)(zhen)蕩(dang)(dang)電(dian)容C7決定(ding)IC1的(de)(de)振(zhen)(zhen)蕩(dang)(dang)頻(pin)率,

   IC2(TL431)為(wei)精(jing)密基準電壓(ya)源(yuan),IC4(光耦(ou)合器4N35)配合用來穩定充(chong)電電壓(ya),調(diao)整RP1(510歐半可調(diao)電位器)可以細調(diao)充(chong)電器的(de)電壓(ya),LED1是(shi)電源(yuan)指示燈.接通電源(yuan)后(hou)該指示燈就會發出(chu)紅色的(de)光。

   VT1開始工作后,變壓(ya)器(qi)的(de)次級6-5繞組輸出的(de)電(dian)壓(ya)經(jing)快速恢復二(er)極管(guan)VD60整流(liu)(liu),C18濾波(bo)得到穩(wen)定的(de)電(dian)壓(ya)(約53V).此電(dian)壓(ya)一(yi)路經(jing)二(er)極管(guan)VD70(該二(er)極管(guan)起(qi)防止電(dian)池的(de)電(dian)流(liu)(liu)倒(dao)灌給充電(dian)器(qi)的(de)作用)給電(dian)池充電(dian),另一(yi)路經(jing)限流(liu)(liu)電(dian)阻R38,穩(wen)壓(ya)二(er)極管(guan)VZD1,濾波(bo)電(dian)容C60,為比較(jiao)器(qi)IC3(LM358)提(ti)供(gong)12V工作電(dian)源,VD12為IC3提(ti)供(gong)基準(zhun)電(dian)壓(ya),經(jing)R25,R26,R27分壓(ya)后送到IC3的(de)2腳和(he)5腳。

   正常充電(dian)時，R33上端有0.18－0.2V的電(dian)壓(ya)，此電(dian)壓(ya)經(jing)R10加到IC3的3腳，從1腳輸(shu)出高(gao)電(dian)平。1腳輸(shu)出的高(gao)電(dian)平信號分三(san)路輸(shu)出，第(di)一路驅動VT2導通，散熱(re)風扇得電(dian)開始(shi)工作(zuo)，第(di)二路經(jing)過電(dian)阻R34點(dian)亮(liang)雙(shuang)色二極(ji)管LED2中的紅色發(fa)光(guang)(guang)(guang)二極(ji)管，第(di)三(san)路輸(shu)入到IC3的6腳，此時7腳輸(shu)出低電(dian)平，雙(shuang)色發(fa)光(guang)(guang)(guang)二極(ji)管LED2中的綠色發(fa)光(guang)(guang)(guang)二極(ji)管熄滅，充電(dian)器進入恒流充電(dian)階段。

   當電池電壓升到44.2V左右時，充電器進入(ru)(ru)恒壓(ya)充(chong)(chong)(chong)電(dian)(dian)階段(duan)，電(dian)(dian)流(liu)逐漸減小。當充(chong)(chong)(chong)電(dian)(dian)電(dian)(dian)流(liu)減小到(dao)200MA－300MA時，R33上端的(de)電(dian)(dian)壓(ya)下降，IC3的(de)3腳電(dian)(dian)壓(ya)低于2腳，1腳輸(shu)(shu)出低電(dian)(dian)平(ping)，雙色發(fa)光二極(ji)(ji)管(guan)(guan)LED2中的(de)紅色發(fa)光二極(ji)(ji)管(guan)(guan)熄滅(mie)，三(san)極(ji)(ji)管(guan)(guan)VT2截止，風扇停(ting)止運轉(zhuan)(zhuan)，同時IC3的(de)7腳輸(shu)(shu)出高(gao)電(dian)(dian)平(ping)，此高(gao)電(dian)(dian)平(ping)一路經(jing)過電(dian)(dian)阻(zu)R35點亮雙色發(fa)光二極(ji)(ji)管(guan)(guan)LED2中的(de)綠色發(fa)光二極(ji)(ji)管(guan)(guan)（指示電(dian)(dian)瓶已經(jing)充(chong)(chong)(chong)滿(man)，此時并沒有真(zhen)(zhen)正充(chong)(chong)(chong)滿(man)，實際上還(huan)得(de)一兩小時才能真(zhen)(zhen)正充(chong)(chong)(chong)滿(man)），另一路經(jing)R52，VD18,R40,RP2到(dao)達IC2的(de)1腳，使(shi)輸(shu)(shu)出電(dian)(dian)壓(ya)降低，充(chong)(chong)(chong)電(dian)(dian)器進入(ru)(ru)200MA-300MA的(de)涓流(liu)充(chong)(chong)(chong)電(dian)(dian)階段(duan)（浮充(chong)(chong)(chong)），改變RP2的(de)電(dian)(dian)阻(zu)值(zhi)可以調整充(chong)(chong)(chong)電(dian)(dian)器由(you)恒流(liu)充(chong)(chong)(chong)電(dian)(dian)狀態轉(zhuan)(zhuan)到(dao)涓流(liu)充(chong)(chong)(chong)電(dian)(dian)狀態的(de)轉(zhuan)(zhuan)折電(dian)(dian)流(liu)（200－300MA）。

常見故障

   這種類型電(dian)動車充電(dian)器的常見故障有下面幾種情況：

1、高壓電(dian)(dian)路故(gu)障：該部分電(dian)(dian)路出現(xian)問題(ti)的主(zhu)要現(xian)象是(shi)指示(shi)燈不(bu)亮(liang)。通常(chang)還(huan)伴有保險絲燒(shao)斷，此時(shi)(shi)應檢(jian)查整流(liu)二(er)極管(guan)VD1-VD4是(shi)否(fou)擊穿，電(dian)(dian)容(rong)C3是(shi)否(fou)炸裂或(huo)者鼓包(bao)，VT2是(shi)否(fou)擊穿，R7,R4是(shi)否(fou)開(kai)路，此時(shi)(shi)更(geng)換(huan)損壞的元(yuan)件(jian)(jian)即可排除故(gu)障，若經常(chang)燒(shao)VT1,且(qie)VT1不(bu)燙手(shou)，則應重點檢(jian)查R1,C4,VD5等元(yuan)器(qi)件(jian)(jian)，若VT1燙手(shou)，則重點檢(jian)查開(kai)關變壓器(qi)次級電(dian)(dian)路中的元(yuan)器(qi)件(jian)(jian)有無(wu)短路或(huo)者漏電(dian)(dian)。

   若紅(hong)色指示(shi)燈(deng)閃爍，則故障多數(shu)是由(you)R2或者(zhe)VD6開路，變壓器T1線腳虛(xu)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（充電器注明不可(ke)隨車攜(xie)帶就是怕RP2因(yin)振動而(er)改變阻值），就會導致輸出(chu)電(dian)壓(ya)漂移。若(ruo)輸出(chu)電(dian)壓(ya)偏(pian)高，電(dian)瓶會過充(chong)，嚴重時會失(shi)水－發燙，最終導致充(chong)爆，若(ruo)輸出(chu)電(dian)壓(ya)偏(pian)低，會導致電(dian)瓶欠充(chong)，縮短其壽命。