傳統的(de)輸入浪涌電(dian)(dian)(dian)流限制方(fang)法(fa)是串聯負溫(wen)度系數(shu)熱敏(min)限流電(dian)(dian)(dian)阻(zu)(zu)器(NTC)，然而這(zhe)種簡單(dan)的(de)方(fang)法(fa)具(ju)有(you)很多缺點：如NTC電(dian)(dian)(dian)阻(zu)(zu)器的(de)限流效果(guo)受環境溫(wen)度影響(xiang)較大、限流效果(guo)在(zai)短暫的(de)輸入主電(dian)(dian)(dian)網中斷(約(yue)幾百毫秒數(shu)量級)時(shi)只能部分地達到、NTC電(dian)(dian)(dian)阻(zu)(zu)器的(de)功率(lv)損耗降低了(le)開關電(dian)(dian)(dian)源的(de)轉換效率(lv)……。其實上面(mian)提出(chu)的(de)這(zhe)兩個問題可以通過一個“軟啟動電(dian)(dian)(dian)路”來解決(jue)，下面(mian)詳細介紹之(zhi)。

　　1 開關(guan)電(dian)源浪涌電(dian)流(liu)產生(sheng)的原因

　　開(kai)關(guan)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)源的(de)輸入電(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)大都采用電(dian)(dian)(dian)(dian)(dian)(dian)(dian)容(rong)(rong)(rong)(rong)濾(lv)波型整流電(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)，在(zai)進線電(dian)(dian)(dian)(dian)(dian)(dian)(dian)源合(he)(he)閘瞬(shun)(shun)間，由于電(dian)(dian)(dian)(dian)(dian)(dian)(dian)容(rong)(rong)(rong)(rong)器上的(de)初始電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓為零，電(dian)(dian)(dian)(dian)(dian)(dian)(dian)容(rong)(rong)(rong)(rong)器充電(dian)(dian)(dian)(dian)(dian)(dian)(dian)瞬(shun)(shun)間會(hui)形成(cheng)很大的(de)浪(lang)涌(yong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)流，特別(bie)是(shi)大功率開(kai)關(guan)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)源，采用容(rong)(rong)(rong)(rong)量較大的(de)濾(lv)波電(dian)(dian)(dian)(dian)(dian)(dian)(dian)容(rong)(rong)(rong)(rong)器，使浪(lang)涌(yong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)流達(da)100A以上。在(zai)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)源接通瞬(shun)(shun)間如此大的(de)浪(lang)涌(yong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)流，重(zhong)者(zhe)往往會(hui)導致(zhi)輸入熔斷(duan)器燒斷(duan)或合(he)(he)閘開(kai)關(guan)的(de)觸點燒壞(huai)，整流橋過流損壞(huai);輕者(zhe)也會(hui)使空(kong)氣開(kai)關(guan)合(he)(he)不上閘。上述現象均會(hui)造成(cheng)開(kai)關(guan)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)源無法正常(chang)工作，為此幾乎所有的(de)開(kai)關(guan)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)源都設置了(le)防止流涌(yong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)流的(de)軟啟(qi)動電(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)，以保證二手機器人電(dian)(dian)(dian)(dian)(dian)(dian)(dian)源正常(chang)而可靠運行。

　　2 軟啟動電(dian)路電(dian)氣工作原理

　　如果采用“軟啟動電路”來消除開關電源啟(qi)(qi)動(dong)(dong)時的(de)(de)浪(lang)(lang)(lang)涌(yong)電(dian)流，可以(yi)很(hen)(hen)好地(di)避免上(shang)述傳(chuan)統浪(lang)(lang)(lang)涌(yong)電(dian)流限(xian)制(zhi)方法的(de)(de)缺點。通過“軟啟(qi)(qi)動(dong)(dong)”來控制(zhi)開關電(dian)源的(de)(de)啟(qi)(qi)動(dong)(dong)以(yi)消除浪(lang)(lang)(lang)涌(yong)電(dian)流，包含這樣兩條設計原則：即在加電(dian)瞬間除去負(fu)載(zai)(zai)、同時限(xian)制(zhi)有(you)用的(de)(de)電(dian)流。如果不驅(qu)動(dong)(dong)負(fu)載(zai)(zai)，開關電(dian)源啟(qi)(qi)動(dong)(dong)時一般電(dian)流很(hen)(hen)小(xiao)。在很(hen)(hen)多情(qing)況下，啟(qi)(qi)動(dong)(dong)電(dian)流實際有(you)可能要比利用這種方法保持的(de)(de)穩態工作電(dian)流小(xiao)。