高壓變頻(pin)器和低壓變頻(pin)器有(you)什(shen)(shen)么(me)區別?又(you)有(you)什(shen)(shen)么(me)聯系呢?下(xia)(xia)面，小編就(jiu)為大(da)家詳(xiang)細(xi)介紹一下(xia)(xia)：

　　1、高壓(ya)變(bian)頻器與(yu)低(di)壓(ya)變(bian)頻器的區別在哪里呢?

　　變頻器大體上(shang)可分為(wei)兩類：高壓變頻器和低壓變頻器。

　　從(cong)用(yong)途來講，適用(yong)對(dui)象(xiang)不(bu)一(yi)樣，高(gao)壓(ya)電機從(cong)調速原(yuan)理來講，二(er)者都是(shi)一(yi)樣的。從(cong)拓撲結構看，二(er)者差別很大(da)(da)，主要是(shi)因為目(mu)前廣泛(fan)應用(yong)的IGBT模(mo)塊耐(nai)壓(ya)不(bu)足造成(cheng)的。高(gao)壓(ya)變頻(pin)器由于(yu)電壓(ya)高(gao)，對(dui)驅動(dong)電路等的干擾也(ye)大(da)(da)，通常都采用(yong)的光纖進行隔離。

　　2、為什(shen)么變頻(pin)器的輸出(chu)電壓與頻(pin)率成比例的改(gai)變?

　　異步電(dian)(dian)(dian)(dian)(dian)動(dong)機的(de)轉(zhuan)矩(ju)是(shi)電(dian)(dian)(dian)(dian)(dian)機的(de)磁(ci)(ci)通(tong)與(yu)轉(zhuan)子內流(liu)(liu)過(guo)的(de)電(dian)(dian)(dian)(dian)(dian)流(liu)(liu)之間相互(hu)作用而產生(sheng)的(de)，在(zai)額(e)定頻(pin)率下，如果電(dian)(dian)(dian)(dian)(dian)壓(ya)(ya) 而只降低頻(pin)率，那(nei)么磁(ci)(ci)通(tong)就過(guo)大，磁(ci)(ci)回(hui)路飽和，電(dian)(dian)(dian)(dian)(dian)機電(dian)(dian)(dian)(dian)(dian)流(liu)(liu) ，嚴重(zhong)時(shi)將(jiang)燒毀電(dian)(dian)(dian)(dian)(dian)機。因此，頻(pin)率與(yu)電(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)要(yao)成比例地改變(bian)，即(ji)改變(bian)頻(pin)率的(de)同時(shi)控制變(bian)頻(pin)器的(de)輸(shu)出電(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)，使電(dian)(dian)(dian)(dian)(dian)動(dong)機的(de)磁(ci)(ci)通(tong)保持 ，避免磁(ci)(ci)飽和現象的(de)產生(sheng)。這就是(shi)VVVF的(de)定義。這里(li)的(de)電(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)指的(de)是(shi)電(dian)(dian)(dian)(dian)(dian)機的(de)線電(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)或者相電(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)的(de) 值。

　　3、電動機使用工頻電源驅(qu)動時，電壓(ya)下降則電流增加;對于(yu)變頻器驅(qu)動，如(ru)果(guo)頻率(lv)下降時電壓(ya)也下降，那么電流是否增加?

　　頻率(lv)(lv)下降(jiang)(低速)時,如果(guo)輸出(chu)相同的(de)功率(lv)(lv),則電(dian)流(liu)增加，但(dan)在轉(zhuan)矩(ju) 的(de)條件下,電(dian)流(liu)幾(ji)乎不變。

　　4、采用(yong)變頻器運轉時，電機的起(qi)動(dong)電流、起(qi)動(dong)轉矩怎(zen)樣?

　　采用變(bian)頻(pin)器(qi)運轉，隨(sui)著電(dian)機的加(jia)速相應(ying)提高(gao)頻(pin)率和電(dian)壓，起(qi)(qi)動(dong)(dong)(dong)電(dian)流被限制在150%額定電(dian)流以(yi)下(根據機種不同，為(wei)(wei)125%～200%)。用工頻(pin)電(dian)源直接起(qi)(qi)動(dong)(dong)(dong)時，起(qi)(qi)動(dong)(dong)(dong)電(dian)流為(wei)(wei)6～7倍，因(yin)此，將產(chan)生機械電(dian)氣上的沖擊。采用變(bian)頻(pin)器(qi)傳動(dong)(dong)(dong)可以(yi)平滑地起(qi)(qi)動(dong)(dong)(dong)(起(qi)(qi)動(dong)(dong)(dong)時間(jian)變(bian)長)。起(qi)(qi)動(dong)(dong)(dong)電(dian)流為(wei)(wei)額定電(dian)流的1.2～1.5倍，起(qi)(qi)動(dong)(dong)(dong)轉矩為(wei)(wei)70%～120%額定轉矩;對(dui)于(yu)帶(dai)有轉矩自動(dong)(dong)(dong) 功能的變(bian)頻(pin)器(qi)，起(qi)(qi)動(dong)(dong)(dong)轉矩為(wei)(wei) 以(yi)上，可以(yi)帶(dai)全(quan)負(fu)載起(qi)(qi)動(dong)(dong)(dong)。

　　5、V/f模式是什么(me)意(yi)思?

　　頻(pin)(pin)率下降時電(dian)(dian)(dian)(dian)(dian)壓(ya)V也成比(bi)例下降，這個問題已(yi)在(zai)回答(da)4說(shuo)明。保持(chi)(chi)V/f比(bi)恒(heng)定控制是異步電(dian)(dian)(dian)(dian)(dian)機(ji)變頻(pin)(pin)調速的(de)(de)(de)(de) 基本的(de)(de)(de)(de)控制方式(shi)，它在(zai)控制電(dian)(dian)(dian)(dian)(dian)機(ji)的(de)(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)源(yuan)頻(pin)(pin)率變化的(de)(de)(de)(de)同時控制變頻(pin)(pin)器(qi)輸出的(de)(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)壓(ya)，并使二者之比(bi)V/f為(wei)恒(heng)定，從而使電(dian)(dian)(dian)(dian)(dian)機(ji)的(de)(de)(de)(de)磁通保持(chi)(chi)恒(heng)定。在(zai)電(dian)(dian)(dian)(dian)(dian)機(ji)額定運(yun)行情況下，電(dian)(dian)(dian)(dian)(dian)機(ji)的(de)(de)(de)(de)定子電(dian)(dian)(dian)(dian)(dian)阻和漏抗(kang)的(de)(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)壓(ya)降比(bi)較小，電(dian)(dian)(dian)(dian)(dian)機(ji)的(de)(de)(de)(de)端電(dian)(dian)(dian)(dian)(dian)壓(ya)和電(dian)(dian)(dian)(dian)(dian)機(ji)的(de)(de)(de)(de)感應電(dian)(dian)(dian)(dian)(dian)勢近似相等(deng)。

　　V/f比(bi)恒(heng)定控(kong)制(zhi)(zhi)存在(zai)的(de)主(zhu)要(yao)問題(ti)是(shi)低速(su)性能(neng)較差(cha)。其原因一(yi)是(shi)低速(su)時(shi)異步電(dian)(dian)(dian)(dian)機(ji)定子(zi)(zi)電(dian)(dian)(dian)(dian)阻電(dian)(dian)(dian)(dian)壓降(jiang)所(suo)占(zhan)比(bi)例變(bian)大，已不(bu)(bu)能(neng)忽(hu)略，不(bu)(bu)能(neng)再認為(wei)定子(zi)(zi)電(dian)(dian)(dian)(dian)壓和電(dian)(dian)(dian)(dian)機(ji)感應電(dian)(dian)(dian)(dian)勢(shi)近似相(xiang)等，仍按(an)V/f比(bi) 控(kong)制(zhi)(zhi)已不(bu)(bu)能(neng)保持電(dian)(dian)(dian)(dian)機(ji)磁通恒(heng)定。電(dian)(dian)(dian)(dian)機(ji)磁通的(de)減(jian)小必(bi)然(ran)造成電(dian)(dian)(dian)(dian)機(ji)的(de)電(dian)(dian)(dian)(dian)磁轉矩(ju)減(jian)小;另外(wai)變(bian)頻器功率器件(jian)的(de) 區時(shi)間(jian)也(ye)是(shi)影響(xiang)電(dian)(dian)(dian)(dian)機(ji)低速(su)性能(neng)的(de)重要(yao)原因， 區時(shi)間(jian)造成電(dian)(dian)(dian)(dian)壓下降(jiang)同時(shi)還(huan)會引起(qi)轉矩(ju)脈動，在(zai) 條件(jian)下還(huan)會引起(qi)轉速(su)、電(dian)(dian)(dian)(dian)流的(de)振蕩。

　　V/f比恒定控制常用(yong)于通用(yong)變(bian)頻器上(shang)。這(zhe)類變(bian)頻器主要用(yong)于風機、水(shui)泵的調(diao)速功能，以及對(dui)調(diao)速范圍要求(qiu)不高的場合。V/f比恒定控制的突出(chu)優點是(shi)可以進行電機的開(kai)環速度控制。

　　6、按比例(li)地(di)改V和f時，電機的(de)轉矩如何變化?

　　頻率下降時(shi)(shi) 成比(bi)例(li)地降低電(dian)壓(ya)，那么由(you)于交流阻(zu)抗變小而電(dian)阻(zu)不變，將造(zao)成在低速下產生(sheng)的(de)(de)(de)轉矩有減小的(de)(de)(de)傾向。因此，在低頻時(shi)(shi)給定V/f,要使(shi)輸(shu)出電(dian)壓(ya)提高一(yi)些,以便(bian)獲得 的(de)(de)(de)起動轉矩,這種補償(chang)稱 起動。可以采用各種方(fang)法實現(xian),有自(zi)動進行的(de)(de)(de)方(fang)法、選(xuan)擇V/f模式或調整電(dian)位器(qi)等方(fang)法。

　　7、所謂開環是什(shen)么意(yi)思?

　　給(gei)(gei)所使用(yong)的電機(ji)裝(zhuang)設速度傳感器(qi)，將實際轉速反饋給(gei)(gei)控(kong)制裝(zhuang)置進(jin)行(xing)控(kong)制的，稱為(wei)“閉(bi)環”，不(bu)用(yong)速度傳感器(qi)運轉的就叫(jiao)作“開(kai)環”，通用(yong)變頻器(qi)多為(wei)開(kai)環方式。

　　8、高壓變頻器自(zi)身的(de)保護功能(neng)

　　輸出(chu)(chu)過(guo)(guo)載、輸出(chu)(chu)過(guo)(guo)流(liu)、電(dian)網(wang)過(guo)(guo)電(dian)壓、電(dian)網(wang)欠(qian)電(dian)壓、電(dian)網(wang)失電(dian)、直流(liu)母(mu)線(xian)過(guo)(guo)電(dian)壓、直流(liu)母(mu)線(xian)欠(qian)電(dian)壓、變壓器過(guo)(guo)熱、缺相、控制電(dian)源(yuan)掉電(dian)、驅動故(gu)障(zhang)、功率器件過(guo)(guo)熱、散熱風機故(gu)障(zhang)、外(wai)部給(gei)定掉線(xian)、接地故(gu)障(zhang)、光纖故(gu)障(zhang)等等