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電動車充電器固障的經典維修方法

電動車以其出行便捷、低碳環保的優勢已進入我們的生活,但它的充電器故障率較高很令人頭疼。出于這個緣故,本人根據多年酌維修經驗,總結了電動車充電器的(de)常見故(gu)障(zhang)的(de)維修方法,供(gong)大(da)家參考。由于(yu)電動車充(chong)電器的(de)輸(shu)入電路(lu)(lu)工作在高電壓、太電流(liu)的(de)狀態下(xia),因此(ci),故(gu)障(zhang)率最高。如高壓大(da)電流(liu)整(zheng)流(liu)三(san)極管、濾波電容、開關功率管等;其次(ci)較易損壞的(de)就是輸(shu)出整(zheng)流(liu)部(bu)分的(de)整(zheng)流(liu)二(er)極管、保(bao)護二(er)極管、濾波電容、限流(liu)電阻等;再就是脈寬調制(zhi)控制(zhi)器的(de)反饋部(bu)分和保(bao)護電路(lu)(lu)部(bu)分。

1.保險絲管熔斷

一般情況(kuang)下(xia),保險絲管(guan)熔斷說明充電(dian)器的內部電(dian)路存在(zai)短路或(huo)過流(liu)的故(gu)障。這是由于(yu)充電(dian)器長時間工作在(zai)高(gao)電(dian)壓(ya)、大(da)電(dian)流(liu)的狀態下(xia),內部器件(jian)的故(gu)障率較(jiao)高(gao)所致。另(ling)外(wai),電(dian)網電(dian)壓(ya)的波動,浪涌都會引起充電(dian)器內電(dian)流(liu)瞬間增大(da)而使(shi)保險絲熔斷。

維修(xiu)方法(fa)∶首先仔(zi)細查看電(dian)(dian)(dian)路(lu)板上(shang)(shang)面的(de)各個元(yuan)件,看這(zhe)些元(yuan)件的(de)外(wai)表是(shi)否(fou)被燒(shao)(shao)糊(hu)或(huo)有(you)電(dian)(dian)(dian)解液溢出(chu),聞―聞有(you)無異昧。再(zai)測(ce)(ce)量(liang)(liang)(liang)(liang)電(dian)(dian)(dian)源輸(shu)(shu)入端的(de)電(dian)(dian)(dian)阻(zu)值(zhi),若小于20OkΩ ,則說(shuo)明后(hou)端有(you)局部短路(lu)現(xian)象(xiang),然(ran)后(hou)分別測(ce)(ce)量(liang)(liang)(liang)(liang)4只整流(liu)二(er)極管正(zheng),反電(dian)(dian)(dian)阻(zu)值(zhi)和兩(liang)個限流(liu)電(dian)(dian)(dian)阻(zu)的(de)阻(zu)值(zhi),看有(you)無短路(lu)或(huo)燒(shao)(shao)壞(huai)(huai)(huai)的(de);最(zui)后(hou)再(zai)測(ce)(ce)量(liang)(liang)(liang)(liang)電(dian)(dian)(dian)源濾波電(dian)(dian)(dian)容(rong)是(shi)否(fou)能進行(xing)正(zheng)常充放電(dian)(dian)(dian)、開(kai)關(guan)功率(lv)管是(shi)否(fou)擊穿(chuan)損(sun)壞(huai)(huai)(huai)、UC3842及周(zhou)圍元(yuan)件是(shi)否(fou)擊穿(chuan),燒(shao)(shao)壞(huai)(huai)(huai)等。需要(yao)說(shuo)明的(de)是(shi),因(yin)是(shi)在路(lu)測(ce)(ce)量(liang)(liang)(liang)(liang),有(you)可(ke)能會使測(ce)(ce)量(liang)(liang)(liang)(liang)結果有(you)誤或(huo)造成(cheng)誤判,因(yin)此(ci)必要(yao)時可(ke)把元(yuan)器(qi)件焊下來測(ce)(ce)量(liang)(liang)(liang)(liang)。如(ru)果仍然(ran)沒有(you)上(shang)(shang)述情況,則測(ce)(ce)量(liang)(liang)(liang)(liang)一下輸(shu)(shu)入電(dian)(dian)(dian)源線(xian)及輸(shu)(shu)出(chu)電(dian)(dian)(dian)源線(xian)是(shi)否(fou)內(nei)部短路(lu)。一般情況上(shang)(shang),在熔斷(duan)器(qi)熔斷(duan)故(gu)障(zhang)中(zhong),整流(liu)二(er)極管,電(dian)(dian)(dian)源濾波電(dian)(dian)(dian)容(rong)、開(kai)關(guan)功率(lv)管、UC3842是(shi)易損(sun)件,損(sun)壞(huai)(huai)(huai)的(de)概率(lv)可(ke)達95%以上(shang)(shang),要(yao)著重(zhong)檢查這(zhe)些元(yuan)器(qi)件,就很容(rong)易排除故(gu)障(zhang)。

2.無直流電壓輸出或電壓輸出不穩定

如果保險絲是完好的,在有(you)負載的惰況下。這類故障要原因有(you):過壓、過流(liu)保護電(dian)(dian)路(lu)出(chu)現(xian)開路(lu),短路(lu)現(xian)象;振(zhen)癆電(dian)(dian)路(lu)沒(mei)有(you)工作;電(dian)(dian)源負載過重,高頻整流(liu)濾(lv)波電(dian)(dian)路(lu)中(zhong)整流(liu)二極管被擊穿:濾(lv)波電(dian)(dian)容漏電(dian)(dian)等。

維修方法:首先,用萬用表測量高頻脈沖變壓器的各個元器件是否有損壞:排除了高頻整流二極管擊穿、負載短路的情況后,再測量各輸出端的直流電壓,如果這時輸出仍為零,則可以肯定是電源的(de)控制(zhi)電路出了故(gu)障(zhang),最后(hou)用萬用表靜態測量高頻濾波電路中整(zheng)流二(er)極管(guan)及(ji)低(di)壓濾波電容是否損壞(huai),如果上述元器件(jian)有損壞(huai),更(geng)換好(hao)新元器件(jian),一般故(gu)障(zhang)即可排除。但要注(zhu)意:輸出線斷線或開焊、虛焊也會造成(cheng)這(zhe)種故(gu)障(zhang),在維(wei)修時應注(zhu)意這(zhe)種情況。

3.無直流電壓輸出,但保險絲絲完好

這(zhe)種現象說明充電器未工作(zuo),或(huo)是工作(zuo)后進入了保護(hu)狀態。

維(wei)修(xiu)方法:首(shou)先應(ying)(ying)判斷一(yi)下充電(dian)(dian)器的(de)變控芯(xin)片UC3842是(shi)否(fou)處(chu)在王(wang)作狀態或(huo)已(yi)經損壞(huai)。具體判斷方法是(shi):加電(dian)(dian)測UC3842的(de)7腳(jiao)(jiao)(jiao)對地(di)電(dian)(dian)壓(ya)(ya),若7腳(jiao)(jiao)(jiao)電(dian)(dian)壓(ya)(ya)正常(chang)并且(qie)8腳(jiao)(jiao)(jiao)有(you)+5∨電(dian)(dian)壓(ya)(ya),1、2、4、6腳(jiao)(jiao)(jiao)也(ye)(ye)會(hui)有(you)不(bu)同的(de)電(dian)(dian)壓(ya)(ya),則說(shuo)(shuo)明電(dian)(dian)路已(yi)啟振,UC3842基本正常(chang)。若7腳(jiao)(jiao)(jiao)電(dian)(dian)壓(ya)(ya)低,其余管腳(jiao)(jiao)(jiao)無電(dian)(dian)壓(ya)(ya),則說(shuo)(shuo)明UC3842已(yi)損壞(huai)。最(zui)常(chang)見的(de)損壞(huai)是(shi)7腳(jiao)(jiao)(jiao)對地(di)擊(ji)(ji)(ji)穿(chuan)(chuan),6、7腳(jiao)(jiao)(jiao)對地(di)擊(ji)(ji)(ji)穿(chuan)(chuan)和1、7腳(jiao)(jiao)(jiao)對地(di)擊(ji)(ji)(ji)穿(chuan)(chuan)。如(ru)果這(zhe)幾只腳(jiao)(jiao)(jiao)都未擊(ji)(ji)(ji)穿(chuan)(chuan),而充電(dian)(dian)器還是(shi)不(bu)能正常(chang)啟動,也(ye)(ye)說(shuo)(shuo)明UC3842已(yi)損壞(huai),應(ying)(ying)直接更換。若判斷芯(xin)片沒有(you)壞(huai),則著(zhu)檢查開(kai)(kai)關這(zhe)柵極(ji)的(de)限(xian)流電(dian)(dian)阻是(shi)否(fou)開(kai)(kai)焊、虛焊或(huo)變值以及開(kai)(kai)關功率管本身是(shi)否(fou)性能不(bu)良。除此(ci)之處(chu),電(dian)(dian)源輸出線(xian)斷線(xian)或(huo)接觸不(bu)良也(ye)(ye)會(hui)造成這(zhe)種故障(zhang),因此(ci)在維(wei)修(xiu)時也(ye)(ye)應(ying)(ying)注意。

4.直流電壓輸出過高

這(zhe)種故障往(wang)往(wang)是由穩壓(ya)取(qu)樣(yang)和穩壓(ya)控制(zhi)電(dian)路異常所至,在充電(dian)器中,直(zhi)流輸出、取(qu)樣(yang)電(dian)阻、誤差取(qu)樣(yang)放大器、光耦合(he)器、電(dian)源控制(zhi)芯片(pian)等共同構成了一個閉合(he)的控制(zhi)環路,任(ren)何一處出問題(ti)會(hui)導致電(dian)壓(ya)升高。

維修方(fang)法:由(you)于(yu)充電(dian)(dian)(dian)(dian)器有過(guo)壓(ya)保(bao)(bao)(bao)(bao)護電(dian)(dian)(dian)(dian)路(lu),輸(shu)出電(dian)(dian)(dian)(dian)壓(ya)過(guo)高(gao)首先(xian)會使過(guo)壓(ya)保(bao)(bao)(bao)(bao)護電(dian)(dian)(dian)(dian)路(lu)動(dong)作(zuo)。因此遇到這(zhe)種故障,我們可以斷(duan)開過(guo)壓(ya)保(bao)(bao)(bao)(bao)護電(dian)(dian)(dian)(dian)路(lu),使這(zhe)壓(ya)保(bao)(bao)(bao)(bao)護電(dian)(dian)(dian)(dian)路(lu)不起作(zuo)用(yong),然后測(ce)(ce)量開機瞬間(jian)的電(dian)(dian)(dian)(dian)源(yuan)主電(dian)(dian)(dian)(dian)壓(ya)。如果測(ce)(ce)量值(zhi)(zhi)比正常值(zhi)(zhi)高(gao)出1V以上,說明輸(shu)出電(dian)(dian)(dian)(dian)壓(ya)過(guo)高(gao)的原(yuan)因確實在控制(zhi)環(huan)路(lu)中。此時應著重檢查取(qu)樣電(dian)(dian)(dian)(dian)阻是否(fou)變(bian)(bian)值(zhi)(zhi)或損壞(huai),精密(mi)基(ji)準電(dian)(dian)(dian)(dian)壓(ya)源(yuan)(TL431)或光(guang)耦器(PC817)是否(fou)性能不良、變(bian)(bian)質或損壞(huai)。其中精密(mi)基(ji)準電(dian)(dian)(dian)(dian)壓(ya)源(yuan)(TL431)極易(yi)損壞(huai),我們可用(yong)下述方(fang)法對精密(mi)穩壓(ya)放大器進行(xing)判別:將(jiang)TL431 的參考端(duan)(Ref)與它(ta)的陰極(Cathode)相連(lian),串1OkΩ的電(dian)(dian)(dian)(dian)阻,接入5∨電(dian)(dian)(dian)(dian)壓(ya)。若陽(yang)極(Anode)與陰極之間(jian)為(wei)2.5V,并且(qie)等侍片(pian)刻(ke)還仍(reng)為(wei)2.5∨,則(ze)為(wei)好管,否(fou)則(ze)為(wei)壞(huai)管。

5.直流電壓輸出過低

根據(ju)維修經驗,除穩(wen)壓(ya)控制電(dian)(dian)路會引(yin)起輸出電(dian)(dian)壓(ya)過(guo)低(di)外,還有以下幾(ji)點原因:

(1)輸出電壓端(duan)整流三極莒、濾(lv)波(bo)電容失效,可以通過代換法進行判斷。

(2)開(kai)關功率管的(de)性能(neng)下降(jiang),導致(zhi)開(kai)關管不能(neng)正(zheng)常導通(tong),使電(dian)源的(de)內阻(zu)增加,帶負(fu)載能(neng)力下降(jiang)。

(3)開(kai)關功率管的(de)源極通(tong)常接一(yi)個阻(zu)(zu)(zu)值(zhi)很小但功率很大的(de)電(dian)阻(zu)(zu)(zu),作為過(guo)(guo)流吳(wu)護檢測電(dian)阻(zu)(zu)(zu)。該電(dian)阻(zu)(zu)(zu)的(de)阻(zu)(zu)(zu)值(zhi)―般在0.2~O.8Ω。如(ru)該電(dian)阻(zu)(zu)(zu)變值(zhi)或開(kai)焊、接觸不良也會造成輸出電(dian)壓(ya)過(guo)(guo)低。

(4)高頻脈沖變壓(ya)器(qi)不良,不但造成(cheng)輸(shu)出黽(min)壓(ya)下降,還會造成(cheng)開關(guan)功率(lv)管激勵不足從(cong)而屢損(sun)開關(guan)管。

(5)高壓直流濾波電(dian)容不良,造成電(dian)源帶負(fu)載能力(li)差。

(6)電(dian)源輸出(chu)線接觸不良(liang),有―定的接觸電(dian)阻,造成輸出(chu)電(dian)壓(ya)過低。

(7)電(dian)(dian)(dian)網(wang)電(dian)(dian)(dian)壓(ya)(ya)過低(di)(di)。雖(sui)然(ran)充(chong)電(dian)(dian)(dian)器(qi)在低(di)(di)玉下(xia)仍然(ran)可以(yi)輸出額(e)定的充(chong)咆電(dian)(dian)(dian)壓(ya)(ya),但當(dang)電(dian)(dian)(dian)網(wang)電(dian)(dian)(dian)壓(ya)(ya)低(di)(di)于充(chong)電(dian)(dian)(dian)器(qi)的最(zui)低(di)(di)電(dian)(dian)(dian)壓(ya)(ya)限定值(zhi)時,也會使輸出電(dian)(dian)(dian)壓(ya)(ya)過低(di)(di)。

維修方法∶首先用萬用表檢查―下高壓直流濾波電容是否變質、容量是否下降、能否正常充放電。如無以上問題,則測量一下開關功率管的電極的限流電阻以及源極的過流保護殮測電阻是否變值、變質或開焊、接觸不良。若無問題,再檢查―下高頻變壓器的鐵(tie)芯是(shi)否完好無損。除此z外還有可能(neng)就是(shi)輸出(chu)(chu)濾波電(dian)(dian)容(rong)容(rong)量降低,或開焊、虛(xu)接(jie);電(dian)(dian)源輸出(chu)(chu)限流電(dian)(dian)阻變值或虛(xu)接(jie);電(dian)(dian)源輸出(chu)(chu)線(xian)虛(xu)接(jie)等。

這些困(kun)素(su)都(dou)不(bu)要放過,都(dou)應仔細檢查,確(que)保(bao)萬無―失(shi)。

6.散熱風扇不轉

這(zhe)種故障原困主要是(shi)控制(zhi)風扇的(de)(de)三(san)極管(一(yi)般(ban)為8550或8050)損(sun)(sun)壞(huai)(huai),或者風扇本身損(sun)(sun)壞(huai)(huai)或風葉被雜物卡住(zhu)。但(dan)有些充(chong)電器申采用的(de)(de)是(shi)智能(neng)散熱,對于采用這(zhe)種方(fang)式散熱的(de)(de)充(chong)電器,熱敏(min)電阻(zu)損(sun)(sun)壞(huai)(huai)的(de)(de)概率(lv)是(shi)很(hen)大的(de)(de)。

扇本身損壞(huai),可(ke)以(yi)把(ba)風(feng)(feng)(feng)扇從(cong)電路板(ban)上(shang)拔下來,另(ling)外接(jie)上(shang)一個12V的直(zhi)流電(注意正、負(fu)極),看是(shi)否(fou)轉動,還要(yao)看有無異物卡住。若擺動凡(fan)下風(feng)(feng)(feng)扇的電線,風(feng)(feng)(feng)扇就(jiu)轉動,則(ze)說明電線內(nei)部有斷線或(huo)接(jie)頭接(jie)觸不(bu)良。若仍不(bu)轉動,則(ze)風(feng)(feng)(feng)扇必(bi)壞(huai)。對于采(cai)用(yong)智能散熱的充(chong)電器(qi)來說,除按上(shang)述(shu)檢(jian)查(cha)外,還應檢(jian)查(cha)一下熱敏電阻(zu)是(shi)否(fou)接(jie)觸不(bu)良或(huo)損壞(huai)、開焊等(deng)。但(dan)要(yao)注意此熱敏電阻(zu)為負(fu)溫度(du)系數(shu),更換時應注意。

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