開關電源變壓器是一種(zhong)增加開關管的電(dian)源變(bian)(bian)壓(ya)(ya)器。除了普通變(bian)(bian)壓(ya)(ya)器的電(dian)壓(ya)(ya)轉換功(gong)能(neng)外，它還具有絕(jue)緣隔離和功(gong)率傳輸功(gong)能(neng)。一般(ban)用于開關電(dian)源等涉及高頻電(dian)路(lu)的場合。

開(kai)(kai)(kai)(kai)(kai)關(guan)(guan)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)變(bian)壓(ya)(ya)(ya)器(qi)的(de)功(gong)能(neng)與分類(lei)開(kai)(kai)(kai)(kai)(kai)關(guan)(guan)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)變(bian)壓(ya)(ya)(ya)器(qi)和開(kai)(kai)(kai)(kai)(kai)關(guan)(guan)管一起形成自激(ji)(ji)(ji)（或他激(ji)(ji)(ji)）間(jian)歇振蕩(dang)器(qi)，將輸(shu)入(ru)(ru)DC電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)調(diao)制為(wei)(wei)高(gao)頻脈(mo)(mo)沖(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)。起到能(neng)量(liang)傳遞和轉(zhuan)換的(de)作用。在反激(ji)(ji)(ji)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)路中(zhong)，當(dang)(dang)開(kai)(kai)(kai)(kai)(kai)關(guan)(guan)管打(da)開(kai)(kai)(kai)(kai)(kai)時，變(bian)壓(ya)(ya)(ya)器(qi)將電(dian)(dian)(dian)(dian)(dian)(dian)(dian)能(neng)轉(zhuan)換為(wei)(wei)磁場能(neng)量(liang)儲存(cun)，當(dang)(dang)開(kai)(kai)(kai)(kai)(kai)關(guan)(guan)管截止時釋放(fang)。在正激(ji)(ji)(ji)式電(dian)(dian)(dian)(dian)(dian)(dian)(dian)路中(zhong)，當(dang)(dang)開(kai)(kai)(kai)(kai)(kai)關(guan)(guan)管通過時，輸(shu)入(ru)(ru)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)直(zhi)接向負(fu)載供應，并將能(neng)量(liang)儲存(cun)在儲能(neng)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)感中(zhong)。當(dang)(dang)開(kai)(kai)(kai)(kai)(kai)關(guan)(guan)管截止時，儲能(neng)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)感繼續流(liu)向負(fu)載。分類(lei)開(kai)(kai)(kai)(kai)(kai)關(guan)(guan)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)變(bian)壓(ya)(ya)(ya)器(qi)分為(wei)(wei)單激(ji)(ji)(ji)開(kai)(kai)(kai)(kai)(kai)關(guan)(guan)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)變(bian)壓(ya)(ya)(ya)器(qi)和雙(shuang)激(ji)(ji)(ji)開(kai)(kai)(kai)(kai)(kai)關(guan)(guan)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)變(bian)壓(ya)(ya)(ya)器(qi)，工作原(yuan)理和結構不相(xiang)同。單激(ji)(ji)(ji)開(kai)(kai)(kai)(kai)(kai)關(guan)(guan)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)變(bian)壓(ya)(ya)(ya)器(qi)的(de)輸(shu)入(ru)(ru)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)為(wei)(wei)單極脈(mo)(mo)沖(chong)(chong)，也分為(wei)(wei)正反激(ji)(ji)(ji)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)輸(shu)出；雙(shuang)激(ji)(ji)(ji)開(kai)(kai)(kai)(kai)(kai)關(guan)(guan)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)變(bian)壓(ya)(ya)(ya)器(qi)的(de)輸(shu)入(ru)(ru)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)為(wei)(wei)雙(shuang)極脈(mo)(mo)沖(chong)(chong)，一般為(wei)(wei)雙(shuang)極脈(mo)(mo)沖(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)輸(shu)出。開(kai)(kai)(kai)(kai)(kai)關(guan)(guan)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)變(bian)壓(ya)(ya)(ya)器(qi)的(de)特性參數(shu)。

電(dian)(dian)壓(ya)比(bi)：指變(bian)壓(ya)器初級(ji)電(dian)(dian)壓(ya)與次級(ji)電(dian)(dian)壓(ya)的比(bi)值。DC電(dian)(dian)阻(zu)(zu)：銅(tong)阻(zu)(zu)。效率(lv):即輸出功(gong)率(lv)/輸入功(gong)率(lv)*100[%]絕緣(yuan)電(dian)(dian)阻(zu)(zu):變(bian)壓(ya)器繞組(zu)和(he)鐵芯(xin)之(zhi)間的絕緣(yuan)能(neng)力(li)。電(dian)(dian)阻(zu)(zu)強度:變(bian)壓(ya)器能(neng)在1秒或1分鐘內承受規定的電(dian)(dian)壓(ya)。

對于開(kai)關(guan)(guan)(guan)(guan)電(dian)(dian)(dian)(dian)(dian)源，開(kai)關(guan)(guan)(guan)(guan)變(bian)(bian)壓(ya)(ya)(ya)(ya)器(qi)(qi)(qi)(qi)的(de)(de)(de)(de)工(gong)(gong)作(zuo)原理(li)不(bu)同于普(pu)通(tong)(tong)變(bian)(bian)壓(ya)(ya)(ya)(ya)器(qi)(qi)(qi)(qi)。普(pu)通(tong)(tong)變(bian)(bian)壓(ya)(ya)(ya)(ya)器(qi)(qi)(qi)(qi)輸(shu)入的(de)(de)(de)(de)交流(liu)(liu)電(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)或電(dian)(dian)(dian)(dian)(dian)流(liu)(liu)的(de)(de)(de)(de)正負(fu)半周波(bo)形是對稱的(de)(de)(de)(de)，輸(shu)入電(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)和電(dian)(dian)(dian)(dian)(dian)流(liu)(liu)波(bo)形一般(ban)是連續的(de)(de)(de)(de)。在(zai)一個周期內，輸(shu)入電(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)和電(dian)(dian)(dian)(dian)(dian)流(liu)(liu)的(de)(de)(de)(de)平均值(zhi)等(deng)于0，這是普(pu)通(tong)(tong)變(bian)(bian)壓(ya)(ya)(ya)(ya)器(qi)(qi)(qi)(qi)工(gong)(gong)作(zuo)原理(li)的(de)(de)(de)(de)基本特(te)征；開(kai)關(guan)(guan)(guan)(guan)變(bian)(bian)壓(ya)(ya)(ya)(ya)器(qi)(qi)(qi)(qi)一般(ban)在(zai)開(kai)關(guan)(guan)(guan)(guan)狀態下(xia)工(gong)(gong)作(zuo)，其輸(shu)入電(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)或電(dian)(dian)(dian)(dian)(dian)流(liu)(liu)一般(ban)不(bu)連續，而是間歇性的(de)(de)(de)(de)。輸(shu)入電(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)或電(dian)(dian)(dian)(dian)(dian)流(liu)(liu)在(zai)一個周期內的(de)(de)(de)(de)平均值(zhi)大多(duo)不(bu)等(deng)于0。因此，開(kai)關(guan)(guan)(guan)(guan)變(bian)(bian)壓(ya)(ya)(ya)(ya)器(qi)(qi)(qi)(qi)又稱脈沖(chong)變(bian)(bian)壓(ya)(ya)(ya)(ya)器(qi)(qi)(qi)(qi)，這是開(kai)關(guan)(guan)(guan)(guan)變(bian)(bian)壓(ya)(ya)(ya)(ya)器(qi)(qi)(qi)(qi)與普(pu)通(tong)(tong)變(bian)(bian)壓(ya)(ya)(ya)(ya)器(qi)(qi)(qi)(qi)工(gong)(gong)作(zuo)原理(li)的(de)(de)(de)(de)最大區別。通(tong)(tong)過(guo)PWM(脈沖(chong)寬度調制(zhi))控制(zhi)開(kai)關(guan)(guan)(guan)(guan)管，導通(tong)(tong)整(zheng)流(liu)(liu)后的(de)(de)(de)(de)直流(liu)(liu)電(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)，使(shi)高頻(pin)電(dian)(dian)(dian)(dian)(dian)流(liu)(liu)流(liu)(liu)入開(kai)關(guan)(guan)(guan)(guan)電(dian)(dian)(dian)(dian)(dian)源的(de)(de)(de)(de)高頻(pin)變(bian)(bian)壓(ya)(ya)(ya)(ya)器(qi)(qi)(qi)(qi)原邊，從而在(zai)變(bian)(bian)壓(ya)(ya)(ya)(ya)器(qi)(qi)(qi)(qi)副邊產生感應電(dian)(dian)(dian)(dian)(dian)流(liu)(liu)。整(zheng)流(liu)(liu)后，可(ke)以(yi)得到所(suo)需的(de)(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)或多(duo)路電(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)。

1、通過觀(guan)察變壓器的外觀(guan)，檢查變壓器是(shi)否有明顯的異常(chang)現象：如線圈引線是(shi)否斷裂、脫焊、絕(jue)緣(yuan)材料是(shi)否有燒焦痕跡、鐵緊固螺釘是(shi)否松動、硅鋼片是(shi)否腐蝕(shi)、繞組線圈是(shi)否暴露等。

2、絕(jue)緣(yuan)(yuan)測(ce)試：用(yong)萬用(yong)表R&TImes；10k檔分別測(ce)量鐵(tie)芯(xin)和初級(ji)(ji)(ji)、初級(ji)(ji)(ji)和次(ci)級(ji)(ji)(ji)。鐵(tie)芯(xin)和次(ci)級(ji)(ji)(ji)。靜電(dian)屏蔽層和次(ci)級(ji)(ji)(ji)。次(ci)級(ji)(ji)(ji)繞組之(zhi)間的電(dian)阻值(zhi)，萬用(yong)表指針應(ying)指在無限位置移動。否則(ze)說明變壓器絕(jue)緣(yuan)(yuan)性能差。

3、線圈通(tong)斷檢(jian)測(ce)(ce)：將萬(wan)用表(biao)放(fang)置在(zai)R&TImes中(zhong)；1.在(zai)測(ce)(ce)試(shi)中(zhong)，如果(guo)繞組(zu)的電阻值無限大，則表(biao)明繞組(zu)有斷路故障。

4、判斷初(chu)級(ji)(ji)和次(ci)級(ji)(ji)線(xian)圈：電源變壓器的初(chu)級(ji)(ji)引(yin)腳和次(ci)級(ji)(ji)引(yin)腳一(yi)般(ban)分別(bie)從兩(liang)側引(yin)出(chu)，初(chu)級(ji)(ji)繞組多標有(you)220V字樣，次(ci)級(ji)(ji)繞組標有(you)額(e)定(ding)電壓值(zhi)，如15V.24V.35V。然(ran)后根據這些標記進行(xing)識別(bie)。

5、空載(zai)電(dian)(dian)流(liu)(liu)檢測：a.直接測量方法(fa)將所有次級(ji)繞(rao)組全部開(kai)路，將萬(wan)用表置(zhi)于交(jiao)流(liu)(liu)電(dian)(dian)流(liu)(liu)擋(500ma，串入(ru)初級(ji)繞(rao)組。當初級(ji)繞(rao)組插(cha)頭(tou)插(cha)入(ru)220V交(jiao)流(liu)(liu)市電(dian)(dian)時，萬(wan)用表指示空載(zai)電(dian)(dian)流(liu)(liu)值。

該值不應大于變壓器滿載(zai)電(dian)(dian)流(liu)的(de)10%~20%。普通電(dian)(dian)子設備電(dian)(dian)源變(bian)(bian)壓器(qi)的(de)正常空載(zai)電(dian)(dian)流(liu)應在100mA左右。如果(guo)超過太多(duo)，說明變(bian)(bian)壓器(qi)有短路故(gu)障。