1、電壓源型與電流源型高(gao)壓變頻(pin)器的區別。

　　變(bian)(bian)頻(pin)器(qi)的(de)主(zhu)電(dian)(dian)(dian)路大體上可分(fen)為兩類：電(dian)(dian)(dian)壓源型(xing)和電(dian)(dian)(dian)流源型(xing)。電(dian)(dian)(dian)壓源型(xing)是(shi)將(jiang)電(dian)(dian)(dian)壓源的(de)直(zhi)(zhi)流變(bian)(bian)換為交流的(de)變(bian)(bian)頻(pin)器(qi)，直(zhi)(zhi)流回路的(de)濾(lv)波(bo)元(yuan)件(jian)(jian)是(shi)電(dian)(dian)(dian)容;電(dian)(dian)(dian)流源型(xing)是(shi)將(jiang)電(dian)(dian)(dian)流源的(de)直(zhi)(zhi)流變(bian)(bian)換為交流的(de)變(bian)(bian)頻(pin)器(qi)，其(qi)直(zhi)(zhi)流回路濾(lv)波(bo)元(yuan)件(jian)(jian)是(shi)電(dian)(dian)(dian)感。

　　2、為什么(me)變(bian)頻器的(de)輸出(chu)電壓與(yu)頻率成比例的(de)改變(bian)?

　　異步(bu)電(dian)(dian)(dian)(dian)動(dong)機的轉(zhuan)矩是電(dian)(dian)(dian)(dian)機的磁(ci)(ci)通與轉(zhuan)子內流過的電(dian)(dian)(dian)(dian)流之間相(xiang)互作用而產生的，在額定頻(pin)(pin)率下，如果電(dian)(dian)(dian)(dian)壓(ya) 而只降(jiang)低頻(pin)(pin)率，那么磁(ci)(ci)通就(jiu)過大(da)，磁(ci)(ci)回路飽和，電(dian)(dian)(dian)(dian)機電(dian)(dian)(dian)(dian)流 ，嚴重時將燒毀電(dian)(dian)(dian)(dian)機。因(yin)此，頻(pin)(pin)率與電(dian)(dian)(dian)(dian)壓(ya)要(yao)成比例地改(gai)(gai)變(bian)，即改(gai)(gai)變(bian)頻(pin)(pin)率的同時控制變(bian)頻(pin)(pin)器的輸出電(dian)(dian)(dian)(dian)壓(ya)，使(shi)電(dian)(dian)(dian)(dian)動(dong)機的磁(ci)(ci)通保持 ，避免磁(ci)(ci)飽和現象的產生。這(zhe)就(jiu)是VVVF的定義。這(zhe)里的電(dian)(dian)(dian)(dian)壓(ya)指的是電(dian)(dian)(dian)(dian)機的線電(dian)(dian)(dian)(dian)壓(ya)或者相(xiang)電(dian)(dian)(dian)(dian)壓(ya)的 值。

　　3、電動機使(shi)用工頻(pin)電源(yuan)驅動時，電壓下(xia)(xia)降(jiang)(jiang)則電流(liu)增(zeng)加;對于變頻(pin)器驅動，如果頻(pin)率下(xia)(xia)降(jiang)(jiang)時電壓也下(xia)(xia)降(jiang)(jiang)，那(nei)么電流(liu)是否(fou)增(zeng)加?

　　頻率下降(低速)時,如果輸出相同的(de)功率,則電流(liu)增加，但在轉矩 的(de)條件下,電流(liu)幾乎不(bu)變。

　　4、采用變頻器運轉(zhuan)時，電機(ji)的起(qi)動(dong)電流、起(qi)動(dong)轉(zhuan)矩怎樣?

　　采用變頻器(qi)(qi)運(yun)轉，隨著電(dian)機的加速(su)相應提高頻率和電(dian)壓，起(qi)動(dong)電(dian)流(liu)(liu)被(bei)限(xian)制在150%額定(ding)(ding)電(dian)流(liu)(liu)以(yi)下(根據機種(zhong)不同，為(wei)(wei)125%～200%)。用工頻電(dian)源直接起(qi)動(dong)時，起(qi)動(dong)電(dian)流(liu)(liu)為(wei)(wei)6～7倍(bei)，因此，將產生機械電(dian)氣上(shang)(shang)的沖擊。采用變頻器(qi)(qi)傳動(dong)可(ke)以(yi)平滑地起(qi)動(dong)(起(qi)動(dong)時間(jian)變長)。起(qi)動(dong)電(dian)流(liu)(liu)為(wei)(wei)額定(ding)(ding)電(dian)流(liu)(liu)的1.2～1.5倍(bei)，起(qi)動(dong)轉矩(ju)(ju)為(wei)(wei)70%～120%額定(ding)(ding)轉矩(ju)(ju);對于帶有轉矩(ju)(ju)自動(dong) 功能(neng)的變頻器(qi)(qi)，起(qi)動(dong)轉矩(ju)(ju)為(wei)(wei) 以(yi)上(shang)(shang)，可(ke)以(yi)帶全(quan)負載起(qi)動(dong)。

　　5、V/f模式是什么意思?

　　頻率下(xia)降(jiang)時電(dian)(dian)(dian)壓(ya)(ya)V也成比(bi)例下(xia)降(jiang)，這個問(wen)題已在回(hui)答4說明(ming)。保(bao)持V/f比(bi)恒(heng)(heng)定(ding)(ding)控(kong)制是異步電(dian)(dian)(dian)機(ji)(ji)變頻調速的(de) 基本的(de)控(kong)制方式，它在控(kong)制電(dian)(dian)(dian)機(ji)(ji)的(de)電(dian)(dian)(dian)源頻率變化的(de)同時控(kong)制變頻器輸出的(de)電(dian)(dian)(dian)壓(ya)(ya)，并使二(er)者之比(bi)V/f為(wei)恒(heng)(heng)定(ding)(ding)，從(cong)而使電(dian)(dian)(dian)機(ji)(ji)的(de)磁通保(bao)持恒(heng)(heng)定(ding)(ding)。在電(dian)(dian)(dian)機(ji)(ji)額定(ding)(ding)運(yun)行情況下(xia)，電(dian)(dian)(dian)機(ji)(ji)的(de)定(ding)(ding)子電(dian)(dian)(dian)阻和漏抗的(de)電(dian)(dian)(dian)壓(ya)(ya)降(jiang)比(bi)較小，電(dian)(dian)(dian)機(ji)(ji)的(de)端電(dian)(dian)(dian)壓(ya)(ya)和電(dian)(dian)(dian)機(ji)(ji)的(de)感(gan)應電(dian)(dian)(dian)勢近似相(xiang)等。