傳(chuan)統的(de)(de)輸入浪涌電流(liu)限(xian)制方法(fa)是串聯負溫(wen)(wen)度系數(shu)熱敏限(xian)流(liu)電阻器(NTC)，然而這(zhe)種簡(jian)單的(de)(de)方法(fa)具有很多缺(que)點：如NTC電阻器的(de)(de)限(xian)流(liu)效(xiao)果受環(huan)境(jing)溫(wen)(wen)度影響較大、限(xian)流(liu)效(xiao)果在短暫的(de)(de)輸入主電網中斷(約幾百毫秒(miao)數(shu)量級)時只能部分地達到、NTC電阻器的(de)(de)功率損耗降低(di)了(le)開(kai)關電源的(de)(de)轉換(huan)效(xiao)率……。其實(shi)上面(mian)提出的(de)(de)這(zhe)兩個問題可以(yi)通過一個“軟啟動電路”來(lai)解決，下(xia)面(mian)詳(xiang)細介(jie)紹之(zhi)。

　　1 開關電源浪(lang)涌電流(liu)產生的原(yuan)因

　　開(kai)關(guan)電(dian)(dian)(dian)(dian)(dian)源(yuan)的輸(shu)入(ru)電(dian)(dian)(dian)(dian)(dian)路大(da)都采用電(dian)(dian)(dian)(dian)(dian)容(rong)(rong)濾波型整流電(dian)(dian)(dian)(dian)(dian)路，在進(jin)線(xian)電(dian)(dian)(dian)(dian)(dian)源(yuan)合(he)(he)閘瞬(shun)間，由于(yu)電(dian)(dian)(dian)(dian)(dian)容(rong)(rong)器上的初始電(dian)(dian)(dian)(dian)(dian)壓(ya)為(wei)(wei)零(ling)，電(dian)(dian)(dian)(dian)(dian)容(rong)(rong)器充電(dian)(dian)(dian)(dian)(dian)瞬(shun)間會形成(cheng)很大(da)的浪(lang)涌(yong)電(dian)(dian)(dian)(dian)(dian)流，特別是大(da)功率開(kai)關(guan)電(dian)(dian)(dian)(dian)(dian)源(yuan)，采用容(rong)(rong)量較大(da)的濾波電(dian)(dian)(dian)(dian)(dian)容(rong)(rong)器，使浪(lang)涌(yong)電(dian)(dian)(dian)(dian)(dian)流達100A以上。在電(dian)(dian)(dian)(dian)(dian)源(yuan)接(jie)通瞬(shun)間如此(ci)大(da)的浪(lang)涌(yong)電(dian)(dian)(dian)(dian)(dian)流，重者往往會導(dao)致輸(shu)入(ru)熔斷器燒斷或合(he)(he)閘開(kai)關(guan)的觸點燒壞(huai)(huai)，整流橋過流損(sun)壞(huai)(huai);輕(qing)者也(ye)會使空氣開(kai)關(guan)合(he)(he)不上閘。上述(shu)現(xian)象均會造成(cheng)開(kai)關(guan)電(dian)(dian)(dian)(dian)(dian)源(yuan)無法正(zheng)常(chang)工作，為(wei)(wei)此(ci)幾乎所(suo)有(you)的開(kai)關(guan)電(dian)(dian)(dian)(dian)(dian)源(yuan)都設置了(le)防止流涌(yong)電(dian)(dian)(dian)(dian)(dian)流的軟啟動電(dian)(dian)(dian)(dian)(dian)路，以保(bao)證二手機器人電(dian)(dian)(dian)(dian)(dian)源(yuan)正(zheng)常(chang)而(er)可靠運行。

　　2 軟啟動電路電氣工作原(yuan)理

　　如果采用“軟啟動電路”來消除開關電源啟(qi)(qi)(qi)動(dong)(dong)時的(de)浪涌電(dian)(dian)(dian)流，可以很(hen)好地(di)避免上述傳(chuan)統(tong)浪涌電(dian)(dian)(dian)流限(xian)制方法的(de)缺點。通過“軟啟(qi)(qi)(qi)動(dong)(dong)”來控制開關電(dian)(dian)(dian)源的(de)啟(qi)(qi)(qi)動(dong)(dong)以消除(chu)浪涌電(dian)(dian)(dian)流，包含這(zhe)樣兩(liang)條(tiao)設計原則：即在(zai)(zai)加電(dian)(dian)(dian)瞬(shun)間除(chu)去負載、同(tong)時限(xian)制有(you)用的(de)電(dian)(dian)(dian)流。如果不驅(qu)動(dong)(dong)負載，開關電(dian)(dian)(dian)源啟(qi)(qi)(qi)動(dong)(dong)時一般電(dian)(dian)(dian)流很(hen)小。在(zai)(zai)很(hen)多情況下，啟(qi)(qi)(qi)動(dong)(dong)電(dian)(dian)(dian)流實際有(you)可能要(yao)比利(li)用這(zhe)種方法保(bao)持的(de)穩(wen)態工作電(dian)(dian)(dian)流小。