電動車充電器(qi)實(shi)際上就(jiu)是(shi)(shi)一個開關電源加上一個檢測電路,目前很多電動車的48V充電器(qi)都是(shi)(shi)采用KA3842和比(bi)較器(qi)LM358來完成充電工作 

工作原理

   220V交流(liu)電(dian)(dian)(dian)(dian)經(jing)LF1雙向濾(lv)波.VD1－VD4整(zheng)流(liu)為(wei)脈動(dong)直流(liu)電(dian)(dian)(dian)(dian)壓(ya)(ya),再經(jing)C3濾(lv)波后形成(cheng)約300V的直流(liu)電(dian)(dian)(dian)(dian)壓(ya)(ya),300V直流(liu)電(dian)(dian)(dian)(dian)壓(ya)(ya)經(jing)過啟動(dong)電(dian)(dian)(dian)(dian)阻R4為(wei)脈寬調(diao)制集成(cheng)電(dian)(dian)(dian)(dian)路(lu)IC1的7腳(jiao)提供啟動(dong)電(dian)(dian)(dian)(dian)壓(ya)(ya),IC1的7腳(jiao)得到(dao)啟動(dong)電(dian)(dian)(dian)(dian)壓(ya)(ya)后,(7腳(jiao)電(dian)(dian)(dian)(dian)壓(ya)(ya)高(gao)于(yu)14V時,集成(cheng)電(dian)(dian)(dian)(dian)路(lu)開(kai)始工(gong)作(zuo)(zuo)),6腳(jiao)輸出PWM脈沖(chong),驅動(dong)電(dian)(dian)(dian)(dian)源開(kai)關管(場效應管)VT7工(gong)作(zuo)(zuo)在開(kai)關狀態,電(dian)(dian)(dian)(dian)流(liu)通過VT1的S極-D極-R7-接地端.此時開(kai)關變壓(ya)(ya)器T1的8-9繞組(zu)產生感應電(dian)(dian)(dian)(dian)壓(ya)(ya),經(jing)VD6，R2為(wei)IC1的7腳(jiao)提供穩定的工(gong)作(zuo)(zuo)電(dian)(dian)(dian)(dian)壓(ya)(ya)，4腳(jiao)外(wai)接振(zhen)蕩(dang)電(dian)(dian)(dian)(dian)阻R10和(he)振(zhen)蕩(dang)電(dian)(dian)(dian)(dian)容C7決定IC1的振(zhen)蕩(dang)頻率,

   IC2(TL431)為(wei)精密基準電壓(ya)源(yuan),IC4(光耦合器4N35)配(pei)合用來(lai)穩定充電電壓(ya),調(diao)整RP1(510歐半可(ke)調(diao)電位器)可(ke)以細調(diao)充電器的電壓(ya),LED1是電源(yuan)指示(shi)燈(deng).接(jie)通電源(yuan)后(hou)該指示(shi)燈(deng)就會發出紅色的光。

   VT1開(kai)始工作后,變壓器的(de)次級(ji)6-5繞組輸出的(de)電(dian)(dian)(dian)壓經(jing)快速(su)恢復二極(ji)(ji)管(guan)(guan)VD60整(zheng)流,C18濾(lv)波得到穩(wen)定的(de)電(dian)(dian)(dian)壓(約53V).此電(dian)(dian)(dian)壓一(yi)(yi)路經(jing)二極(ji)(ji)管(guan)(guan)VD70(該二極(ji)(ji)管(guan)(guan)起防止電(dian)(dian)(dian)池(chi)的(de)電(dian)(dian)(dian)流倒灌給(gei)充電(dian)(dian)(dian)器的(de)作用(yong))給(gei)電(dian)(dian)(dian)池(chi)充電(dian)(dian)(dian),另(ling)一(yi)(yi)路經(jing)限流電(dian)(dian)(dian)阻R38,穩(wen)壓二極(ji)(ji)管(guan)(guan)VZD1,濾(lv)波電(dian)(dian)(dian)容C60,為(wei)比較器IC3(LM358)提(ti)供12V工作電(dian)(dian)(dian)源,VD12為(wei)IC3提(ti)供基準電(dian)(dian)(dian)壓,經(jing)R25,R26,R27分壓后送到IC3的(de)2腳(jiao)和(he)5腳(jiao)。

   正(zheng)常充電(dian)(dian)時，R33上端有0.18－0.2V的(de)電(dian)(dian)壓(ya)(ya)，此(ci)電(dian)(dian)壓(ya)(ya)經(jing)R10加到(dao)IC3的(de)3腳，從1腳輸出高電(dian)(dian)平。1腳輸出的(de)高電(dian)(dian)平信(xin)號分(fen)三路(lu)輸出，第一路(lu)驅動VT2導通，散熱風扇得(de)電(dian)(dian)開始工(gong)作，第二(er)(er)路(lu)經(jing)過電(dian)(dian)阻R34點(dian)亮雙色(se)二(er)(er)極(ji)管(guan)LED2中(zhong)的(de)紅色(se)發光二(er)(er)極(ji)管(guan)，第三路(lu)輸入到(dao)IC3的(de)6腳，此(ci)時7腳輸出低(di)電(dian)(dian)平，雙色(se)發光二(er)(er)極(ji)管(guan)LED2中(zhong)的(de)綠色(se)發光二(er)(er)極(ji)管(guan)熄滅，充電(dian)(dian)器進入恒(heng)流充電(dian)(dian)階段。

   當電池電壓升到44.2V左右時，充電器進(jin)入(ru)恒(heng)壓(ya)(ya)充電(dian)(dian)(dian)(dian)(dian)(dian)(dian)階段，電(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)逐漸(jian)減小(xiao)。當充電(dian)(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)減小(xiao)到(dao)200MA－300MA時，R33上端的(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)下降(jiang)，IC3的(de)(de)3腳電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)低于(yu)2腳，1腳輸(shu)出(chu)低電(dian)(dian)(dian)(dian)(dian)(dian)(dian)平，雙色(se)發光二極(ji)(ji)管(guan)(guan)(guan)LED2中的(de)(de)紅色(se)發光二極(ji)(ji)管(guan)(guan)(guan)熄滅，三極(ji)(ji)管(guan)(guan)(guan)VT2截止，風扇停止運轉(zhuan)，同時IC3的(de)(de)7腳輸(shu)出(chu)高電(dian)(dian)(dian)(dian)(dian)(dian)(dian)平，此高電(dian)(dian)(dian)(dian)(dian)(dian)(dian)平一(yi)路(lu)(lu)經過電(dian)(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)R35點(dian)亮雙色(se)發光二極(ji)(ji)管(guan)(guan)(guan)LED2中的(de)(de)綠色(se)發光二極(ji)(ji)管(guan)(guan)(guan)（指(zhi)示電(dian)(dian)(dian)(dian)(dian)(dian)(dian)瓶已(yi)經充滿，此時并沒(mei)有真(zhen)正充滿，實(shi)際上還得一(yi)兩(liang)小(xiao)時才能真(zhen)正充滿），另一(yi)路(lu)(lu)經R52，VD18,R40,RP2到(dao)達(da)IC2的(de)(de)1腳，使輸(shu)出(chu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)降(jiang)低，充電(dian)(dian)(dian)(dian)(dian)(dian)(dian)器進(jin)入(ru)200MA-300MA的(de)(de)涓流(liu)充電(dian)(dian)(dian)(dian)(dian)(dian)(dian)階段（浮充），改變RP2的(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)值可以調整(zheng)充電(dian)(dian)(dian)(dian)(dian)(dian)(dian)器由恒(heng)流(liu)充電(dian)(dian)(dian)(dian)(dian)(dian)(dian)狀態(tai)轉(zhuan)到(dao)涓流(liu)充電(dian)(dian)(dian)(dian)(dian)(dian)(dian)狀態(tai)的(de)(de)轉(zhuan)折(zhe)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)（200－300MA）。

常見故障

   這種(zhong)類型電動(dong)車充電器(qi)的常見(jian)故障有下面幾種(zhong)情況：

1、高壓電(dian)路(lu)(lu)故(gu)障：該部分電(dian)路(lu)(lu)出現問(wen)題的主要現象是指(zhi)示燈不亮。通常(chang)還(huan)伴有保(bao)險絲燒(shao)斷，此(ci)時應(ying)檢(jian)查整流二極管VD1-VD4是否擊(ji)穿，電(dian)容C3是否炸裂或者鼓(gu)包，VT2是否擊(ji)穿，R7,R4是否開路(lu)(lu)，此(ci)時更換損(sun)壞的元(yuan)件即(ji)可排除故(gu)障，若經常(chang)燒(shao)VT1,且VT1不燙(tang)手(shou)，則(ze)應(ying)重點檢(jian)查R1,C4,VD5等(deng)元(yuan)器件，若VT1燙(tang)手(shou)，則(ze)重點檢(jian)查開關變壓器次級電(dian)路(lu)(lu)中的元(yuan)器件有無短路(lu)(lu)或者漏電(dian)。

   若紅色(se)指(zhi)示燈閃爍，則故障多數是由R2或者VD6開路(lu)，變壓器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（充電器注明不可隨車攜(xie)帶就是(shi)怕RP2因振動而改變阻(zu)值），就會導(dao)致(zhi)輸出(chu)電(dian)壓漂移(yi)。若輸出(chu)電(dian)壓偏(pian)高，電(dian)瓶會過(guo)充，嚴(yan)重時會失水－發燙，最終導(dao)致(zhi)充爆，若輸出(chu)電(dian)壓偏(pian)低，會導(dao)致(zhi)電(dian)瓶欠充，縮短其(qi)壽命。