48V電動車充電器原理圖與維修
電(dian)動車(che)充(chong)電(dian)器(qi)(qi)實際(ji)上就是(shi)一個開關電(dian)源加上一個檢測電(dian)路,目前很(hen)多電(dian)動車(che)的48V充(chong)電(dian)器(qi)(qi)都(dou)是(shi)采用(yong)KA3842和比較器(qi)(qi)LM358來完成(cheng)充(chong)電(dian)工(gong)作
工作原理
220V交流(liu)(liu)電(dian)(dian)(dian)(dian)經(jing)(jing)LF1雙向濾(lv)波.VD1－VD4整流(liu)(liu)為(wei)脈(mo)動直流(liu)(liu)電(dian)(dian)(dian)(dian)壓,再(zai)經(jing)(jing)C3濾(lv)波后形成(cheng)約300V的(de)(de)直流(liu)(liu)電(dian)(dian)(dian)(dian)壓,300V直流(liu)(liu)電(dian)(dian)(dian)(dian)壓經(jing)(jing)過啟動電(dian)(dian)(dian)(dian)阻R4為(wei)脈(mo)寬(kuan)調(diao)制集(ji)成(cheng)電(dian)(dian)(dian)(dian)路(lu)IC1的(de)(de)7腳(jiao)提供啟動電(dian)(dian)(dian)(dian)壓,IC1的(de)(de)7腳(jiao)得到啟動電(dian)(dian)(dian)(dian)壓后,(7腳(jiao)電(dian)(dian)(dian)(dian)壓高于14V時(shi),集(ji)成(cheng)電(dian)(dian)(dian)(dian)路(lu)開(kai)始工(gong)作(zuo)),6腳(jiao)輸出PWM脈(mo)沖,驅動電(dian)(dian)(dian)(dian)源開(kai)關(guan)管(場效應管)VT7工(gong)作(zuo)在(zai)開(kai)關(guan)狀態,電(dian)(dian)(dian)(dian)流(liu)(liu)通過VT1的(de)(de)S極-D極-R7-接地端(duan).此時(shi)開(kai)關(guan)變壓器T1的(de)(de)8-9繞組(zu)產生感應電(dian)(dian)(dian)(dian)壓,經(jing)(jing)VD6，R2為(wei)IC1的(de)(de)7腳(jiao)提供穩(wen)定(ding)的(de)(de)工(gong)作(zuo)電(dian)(dian)(dian)(dian)壓，4腳(jiao)外接振(zhen)蕩電(dian)(dian)(dian)(dian)阻R10和振(zhen)蕩電(dian)(dian)(dian)(dian)容C7決定(ding)IC1的(de)(de)振(zhen)蕩頻率,
IC2(TL431)為(wei)精密基準電(dian)壓(ya)源,IC4(光(guang)耦合(he)器4N35)配合(he)用來穩定充電(dian)電(dian)壓(ya),調(diao)整RP1(510歐半(ban)可調(diao)電(dian)位器)可以細調(diao)充電(dian)器的電(dian)壓(ya),LED1是電(dian)源指示燈.接通電(dian)源后該指示燈就會發(fa)出紅色的光(guang)。
VT1開始工作(zuo)后(hou),變壓(ya)(ya)器(qi)的(de)次級6-5繞組輸出的(de)電(dian)壓(ya)(ya)經快速恢復二極管(guan)VD60整流,C18濾(lv)波得到穩(wen)定的(de)電(dian)壓(ya)(ya)(約53V).此電(dian)壓(ya)(ya)一路經二極管(guan)VD70(該二極管(guan)起防(fang)止電(dian)池的(de)電(dian)流倒(dao)灌給充電(dian)器(qi)的(de)作(zuo)用)給電(dian)池充電(dian),另(ling)一路經限流電(dian)阻R38,穩(wen)壓(ya)(ya)二極管(guan)VZD1,濾(lv)波電(dian)容C60,為比較器(qi)IC3(LM358)提供12V工作(zuo)電(dian)源,VD12為IC3提供基準電(dian)壓(ya)(ya),經R25,R26,R27分(fen)壓(ya)(ya)后(hou)送到IC3的(de)2腳和5腳。
正(zheng)常(chang)充(chong)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(chu)高電(dian)平。1腳輸(shu)出(chu)的高電(dian)平信號分三(san)路(lu)輸(shu)出(chu)，第一(yi)路(lu)驅動(dong)VT2導通，散熱風扇(shan)得電(dian)開始工(gong)作，第二(er)(er)(er)路(lu)經(jing)過(guo)電(dian)阻R34點亮雙(shuang)色二(er)(er)(er)極(ji)管(guan)(guan)LED2中(zhong)(zhong)的紅色發光二(er)(er)(er)極(ji)管(guan)(guan)，第三(san)路(lu)輸(shu)入到IC3的6腳，此時7腳輸(shu)出(chu)低電(dian)平，雙(shuang)色發光二(er)(er)(er)極(ji)管(guan)(guan)LED2中(zhong)(zhong)的綠(lv)色發光二(er)(er)(er)極(ji)管(guan)(guan)熄滅(mie)，充(chong)電(dian)器進入恒流(liu)充(chong)電(dian)階段。
當電池電壓升到44.2V左右時，充電器進(jin)入恒壓充(chong)電(dian)(dian)階(jie)段，電(dian)(dian)流(liu)(liu)逐漸減(jian)小。當充(chong)電(dian)(dian)電(dian)(dian)流(liu)(liu)減(jian)小到200MA－300MA時，R33上(shang)端的(de)(de)電(dian)(dian)壓下(xia)降，IC3的(de)(de)3腳電(dian)(dian)壓低(di)于2腳，1腳輸出(chu)低(di)電(dian)(dian)平，雙(shuang)色(se)發光(guang)二極管(guan)(guan)LED2中的(de)(de)紅色(se)發光(guang)二極管(guan)(guan)熄滅，三(san)極管(guan)(guan)VT2截止，風扇停止運轉(zhuan)，同時IC3的(de)(de)7腳輸出(chu)高電(dian)(dian)平，此(ci)高電(dian)(dian)平一路經過電(dian)(dian)阻R35點亮雙(shuang)色(se)發光(guang)二極管(guan)(guan)LED2中的(de)(de)綠色(se)發光(guang)二極管(guan)(guan)（指示電(dian)(dian)瓶已經充(chong)滿(man)，此(ci)時并沒(mei)有真(zhen)正充(chong)滿(man)，實際上(shang)還得一兩小時才能真(zhen)正充(chong)滿(man)），另(ling)一路經R52，VD18,R40,RP2到達(da)IC2的(de)(de)1腳，使輸出(chu)電(dian)(dian)壓降低(di)，充(chong)電(dian)(dian)器(qi)進(jin)入200MA-300MA的(de)(de)涓流(liu)(liu)充(chong)電(dian)(dian)階(jie)段（浮充(chong)），改(gai)變RP2的(de)(de)電(dian)(dian)阻值(zhi)可以調整充(chong)電(dian)(dian)器(qi)由恒流(liu)(liu)充(chong)電(dian)(dian)狀(zhuang)態轉(zhuan)到涓流(liu)(liu)充(chong)電(dian)(dian)狀(zhuang)態的(de)(de)轉(zhuan)折電(dian)(dian)流(liu)(liu)（200－300MA）。
常見故障
這種類型電(dian)動車充(chong)電(dian)器的常見故障(zhang)有(you)下面幾種情況：
1、高(gao)壓(ya)電(dian)路故障(zhang)：該(gai)部(bu)分電(dian)路出現問題的主要現象(xiang)是(shi)(shi)指示燈不亮(liang)。通常還伴有保險(xian)絲(si)燒斷，此(ci)時應檢查(cha)(cha)整流二極(ji)管(guan)VD1-VD4是(shi)(shi)否擊穿，電(dian)容(rong)C3是(shi)(shi)否炸裂或(huo)者鼓包，VT2是(shi)(shi)否擊穿，R7,R4是(shi)(shi)否開(kai)路，此(ci)時更換損壞的元(yuan)件即可排除故障(zhang)，若經常燒VT1,且VT1不燙手(shou)，則(ze)應重點檢查(cha)(cha)R1,C4,VD5等元(yuan)器件，若VT1燙手(shou)，則(ze)重點檢查(cha)(cha)開(kai)關(guan)變壓(ya)器次級電(dian)路中的元(yuan)器件有無短路或(huo)者漏電(dian)。
若紅色(se)指示燈閃爍，則故(gu)障多數是由R2或(huo)者VD6開路，變壓器T1線腳虛焊引起(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(jiu)是怕(pa)RP2因振動而改變(bian)阻值），就(jiu)會導(dao)致(zhi)輸(shu)出(chu)電壓漂移。若輸(shu)出(chu)電壓偏(pian)(pian)高，電瓶(ping)會過充，嚴重(zhong)時會失水－發燙，最終(zhong)導(dao)致(zhi)充爆，若輸(shu)出(chu)電壓偏(pian)(pian)低，會導(dao)致(zhi)電瓶(ping)欠充，縮(suo)短(duan)其壽命。