變頻器(qi)(qi)是(shi)(shi)一(yi)(yi)種將工(gong)頻電源變換為(wei)另一(yi)(yi)頻率的(de)電能(neng)控制裝置，變頻器(qi)(qi)主要的(de)作(zuo)用之一(yi)(yi)就是(shi)(shi)調速(su)，那(nei)么(me)西(xi)門子直流調速(su)器(qi)(qi)是(shi)(shi)什(shen)么(me)呢(ni)，它的(de)工(gong)作(zuo)原理又(you)是(shi)(shi)怎樣(yang)呢(ni)?

　　一、 西(xi)門(men)子直(zhi)流(liu)(liu)調(diao)(diao)速(su)(su)器(qi)是一種(zhong)電(dian)(dian)(dian)機調(diao)(diao)速(su)(su)裝置，包括電(dian)(dian)(dian)機直(zhi)流(liu)(liu)調(diao)(diao)速(su)(su)器(qi)、脈寬(kuan)直(zhi)流(liu)(liu)調(diao)(diao)速(su)(su)器(qi)、可控硅直(zhi)流(liu)(liu)調(diao)(diao)速(su)(su)器(qi)等，一般為模塊式直(zhi)流(liu)(liu)電(dian)(dian)(dian)機調(diao)(diao)速(su)(su)器(qi)，集(ji)電(dian)(dian)(dian)源、控制(zhi)、驅動電(dian)(dian)(dian)路于一體(ti)。具有體(ti)積小、重量輕等特點(dian)，可單獨使用也可直(zhi)接安裝在直(zhi)流(liu)(liu)電(dian)(dian)(dian)機上構成(cheng)一體(ti)化直(zhi)流(liu)(liu)調(diao)(diao)速(su)(su)電(dian)(dian)(dian)機，可具有調(diao)(diao)速(su)(su)器(qi)所(suo)應(ying)有的(de) 功能。

　　二、工(gong)作原理

　　直(zhi)流(liu)(liu)調(diao)速器(qi)就是調(diao)節直(zhi)流(liu)(liu)電(dian)(dian)(dian)動機(ji)(ji)速度(du)的設備。上端和交流(liu)(liu)電(dian)(dian)(dian)源(yuan)連接，下端和直(zhi)流(liu)(liu)電(dian)(dian)(dian)動機(ji)(ji)連接，直(zhi)流(liu)(liu)調(diao)速器(qi)將交流(liu)(liu)電(dian)(dian)(dian)轉(zhuan)換成兩路(lu)輸(shu)出(chu)直(zhi)流(liu)(liu)電(dian)(dian)(dian)源(yuan)，一(yi)路(lu)輸(shu)入給直(zhi)流(liu)(liu)電(dian)(dian)(dian)機(ji)(ji)勵磁(定子)，一(yi)路(lu)輸(shu)入給直(zhi)流(liu)(liu)電(dian)(dian)(dian)機(ji)(ji)電(dian)(dian)(dian)樞(轉(zhuan)子)，直(zhi)流(liu)(liu)調(diao)速器(qi)通過控制電(dian)(dian)(dian)樞直(zhi)流(liu)(liu)電(dian)(dian)(dian)壓來(lai)調(diao)節直(zhi)流(liu)(liu)電(dian)(dian)(dian)動機(ji)(ji)轉(zhuan)速。同時直(zhi)流(liu)(liu)電(dian)(dian)(dian)動機(ji)(ji)給調(diao)速器(qi)一(yi)個反(fan)饋(kui)電(dian)(dian)(dian)流(liu)(liu)，調(diao)速器(qi)根據反(fan)饋(kui)電(dian)(dian)(dian)流(liu)(liu)來(lai)判斷直(zhi)流(liu)(liu)電(dian)(dian)(dian)機(ji)(ji)的轉(zhuan)速情(qing)況， 時修(xiu)正(zheng)電(dian)(dian)(dian)樞電(dian)(dian)(dian)壓輸(shu)出(chu)，一(yi)次來(lai)再次調(diao)節電(dian)(dian)(dian)機(ji)(ji)的轉(zhuan)速。

　　下列(lie)場合需要使(shi)用(yong)直流調速(su)器：

　　1、需(xu)要(yao)較寬的調速(su)范圍;

　　2、需要較快的動態響應過(guo)程(cheng);

　　3、加、減速(su)時需要自動平滑的過度(du)過程;

　　4、需要低速運轉時(shi)力矩大;

　　5、需要較(jiao)好的挖土機特性，能(neng)將過載(zai)電流(liu)自動限制(zhi)在(zai)設定電流(liu)上。