一、步進電機是直流還是交流
步進電機不是(shi)交流(liu)(liu)電(dian)(dian)(dian)機(ji)(ji)而是(shi)直(zhi)流(liu)(liu)電(dian)(dian)(dian)機(ji)(ji)。步進(jin)電(dian)(dian)(dian)機(ji)(ji)是(shi)一種感應(ying)電(dian)(dian)(dian)機(ji)(ji),它的工作(zuo)(zuo)原(yuan)理是(shi)利用(yong)電(dian)(dian)(dian)子電(dian)(dian)(dian)路,將直(zhi)流(liu)(liu)電(dian)(dian)(dian)變成分(fen)時(shi)供電(dian)(dian)(dian)的,多相時(shi)序控制(zhi)電(dian)(dian)(dian)流(liu)(liu),用(yong)這種電(dian)(dian)(dian)流(liu)(liu)為電(dian)(dian)(dian)機(ji)(ji)供電(dian)(dian)(dian),電(dian)(dian)(dian)機(ji)(ji)才能正常工作(zuo)(zuo),驅動器就是(shi)為電(dian)(dian)(dian)機(ji)(ji)分(fen)時(shi)供電(dian)(dian)(dian)的,多相時(shi)序控制(zhi)器。
雖(sui)然步進電(dian)機已被廣泛地(di)應用,但這樣的(de)電(dian)機并不能(neng)像(xiang)普通的(de)直流電(dian)機,交流電(dian)機在常(chang)規下(xia)使(shi)用。它(ta)必須由(you)雙(shuang)環(huan)形脈沖(chong)信(xin)號、功率(lv)驅(qu)動(dong)電(dian)路(lu)等(deng)組成控制系統方可使(shi)用。通常(chang)電(dian)機的(de)轉(zhuan)(zhuan)子為(wei)永磁(ci)(ci)(ci)體,當電(dian)流流過定(ding)子繞組時,定(ding)子繞組產(chan)生一(yi)矢量磁(ci)(ci)(ci)場(chang)(chang)(chang)。該磁(ci)(ci)(ci)場(chang)(chang)(chang)會帶動(dong)轉(zhuan)(zhuan)子旋轉(zhuan)(zhuan)一(yi)角(jiao)度(du),使(shi)得轉(zhuan)(zhuan)子的(de)一(yi)對磁(ci)(ci)(ci)場(chang)(chang)(chang)方向與定(ding)子的(de)磁(ci)(ci)(ci)場(chang)(chang)(chang)方向一(yi)致。當定(ding)子的(de)矢量磁(ci)(ci)(ci)場(chang)(chang)(chang)旋轉(zhuan)(zhuan)一(yi)個角(jiao)度(du)。轉(zhuan)(zhuan)子也隨著(zhu)該磁(ci)(ci)(ci)場(chang)(chang)(chang)轉(zhuan)(zhuan)一(yi)個角(jiao)度(du)。
每當輸入(ru)一(yi)(yi)個(ge)電(dian)脈(mo)沖(chong),電(dian)動機(ji)轉動一(yi)(yi)個(ge)角度前進一(yi)(yi)步。它輸出(chu)的角位移與輸入(ru)的脈(mo)沖(chong)數成正(zheng)比、轉速與脈(mo)沖(chong)頻(pin)率(lv)成正(zheng)比。改變繞組通電(dian)的順(shun)序(xu),電(dian)機(ji)就會反(fan)轉。所以可用控(kong)制脈(mo)沖(chong)數量、頻(pin)率(lv)及電(dian)動機(ji)各(ge)相繞組的通電(dian)順(shun)序(xu)來控(kong)制步進電(dian)機(ji)的轉動。
二、步進電機是無刷電機嗎
步進電機其實是一種特殊的直流無刷電機,只不過步進電機特性特殊,不再劃歸到直流無刷電機類別里。和直流無刷電機相比,步進電機不帶反饋就可以精確地控制電機的位置和速度,而無刷電機不(bu)行;同樣尺寸的情況下,步進(jin)(jin)電機(ji)的輸(shu)出(chu)力(li)矩(ju)比較(jiao)大(da),但跑高速扭矩(ju)不(bu)行;步進(jin)(jin)電機(ji)是(shi)一步步旋轉的,噪聲比無刷電機(ji)大(da);通常步進(jin)(jin)電機(ji)效(xiao)率也比無刷電機(ji)低,所(suo)以發熱量(liang)會(hui)大(da)一些。
其實步進電機、直流電(dian)機和無刷(shua)直流電(dian)機之間主要不同(tong)就是驅動方(fang)式。
1、步(bu)(bu)進(jin)電(dian)(dian)機以(yi)(yi)(yi)步(bu)(bu)階方(fang)(fang)式(shi)分段移動,采(cai)用(yong)直接控(kong)(kong)制方(fang)(fang)式(shi),其(qi)主(zhu)要指(zhi)令(ling)和控(kong)(kong)制變量(liang)為步(bu)(bu)進(jin)位置。主(zhu)要以(yi)(yi)(yi)“開環模(mo)式(shi)”運行,步(bu)(bu)進(jin)電(dian)(dian)機由單脈沖(chong)電(dian)(dian)壓直接驅動,不需要霍爾(er)元件(jian)定(ding)位。通過控(kong)(kong)制添(tian)加到電(dian)(dian)機的脈沖(chong)數,可以(yi)(yi)(yi)精(jing)確定(ding)位旋(xuan)轉角(jiao)度。
2、直(zhi)流電(dian)(dian)機(ji)通常采用連續運動控制(zhi)方式,以電(dian)(dian)機(ji)電(dian)(dian)壓為(wei)控制(zhi)變量,位置或速度(du)為(wei)指令變量,需(xu)要(yao)一個反(fan)饋控制(zhi)系統(tong),該系統(tong)將間(jian)接控制(zhi)電(dian)(dian)機(ji)位置,無刷直(zhi)流電(dian)(dian)機(ji)轉速高于步進(jin)電(dian)(dian)機(ji)。
3、由(you)于(yu)(yu)驅(qu)動原理(li)不同(tong),一般無刷直(zhi)流電機(ji)(ji)用(yong)于(yu)(yu)控制精度(du)不高(gao)的場(chang)(chang)合。步(bu)進(jin)電機(ji)(ji)用(yong)于(yu)(yu)需要控制精度(du)的場(chang)(chang)合。