說起步進電機(ji)，對于電氣控制(zhi)行業的工程(cheng)師來說應該再熟悉不(bu)過了!它的誤差(cha)不(bu)會長期積累，能(neng)夠實現定位，控制(zhi)比伺服簡單等特點，但步進電機(ji)控制(zhi)的前提是電機(ji)不(bu)發生失(shi)步，如(ru)何才能(neng)步進電機(ji)失(shi)步?

  步(bu)進(jin)(jin)電(dian)(dian)(dian)(dian)機(ji)(ji)(ji)是將電(dian)(dian)(dian)(dian)脈沖信(xin)(xin)號(hao)轉變為角(jiao)(jiao)(jiao)位移(yi)或(huo)(huo)線位移(yi)的(de)開(kai)環控(kong)制(zhi)(zhi)電(dian)(dian)(dian)(dian)機(ji)(ji)(ji)。在未發(fa)生失步(bu)情況下(xia)，電(dian)(dian)(dian)(dian)機(ji)(ji)(ji)的(de)轉速、停止(zhi)的(de)位置只取(qu)決(jue)于(yu)脈沖信(xin)(xin)號(hao)的(de)頻率(lv)和(he)脈沖數(shu)(shu)并(bing)不受負載變化的(de)影響，當步(bu)進(jin)(jin)電(dian)(dian)(dian)(dian)機(ji)(ji)(ji)接收到(dao)一(yi)個(ge)脈沖信(xin)(xin)號(hao)時(shi)，電(dian)(dian)(dian)(dian)機(ji)(ji)(ji)就按設定(ding)的(de)方(fang)向轉一(yi)個(ge)固定(ding)的(de)角(jiao)(jiao)(jiao)度(du)(步(bu)進(jin)(jin)角(jiao)(jiao)(jiao)或(huo)(huo)步(bu)距(ju)角(jiao)(jiao)(jiao))，通過控(kong)制(zhi)(zhi)脈沖數(shu)(shu)和(he)脈沖頻率(lv)來控(kong)制(zhi)(zhi)電(dian)(dian)(dian)(dian)機(ji)(ji)(ji)角(jiao)(jiao)(jiao)位移(yi)量及電(dian)(dian)(dian)(dian)機(ji)(ji)(ji)轉速從而達到(dao)的(de)開(kai)環控(kong)制(zhi)(zhi)。另(ling)外，步(bu)進(jin)(jin)電(dian)(dian)(dian)(dian)機(ji)(ji)(ji)每(mei)走一(yi)步(bu)所(suo)轉過的(de)角(jiao)(jiao)(jiao)度(du)與(yu)理論步(bu)距(ju)之間總有(you)(you)一(yi)定(ding)的(de)誤差(cha)，從某一(yi)步(bu)到(dao)一(yi)步(bu)，也總有(you)(you)一(yi)定(ding)的(de)誤差(cha)，但是，步(bu)進(jin)(jin)電(dian)(dian)(dian)(dian)機(ji)(ji)(ji)每(mei)轉一(yi)周(zhou)的(de)步(bu)數(shu)(shu)相(xiang)同，在不失步(bu)的(de)情況下(xia)，其(qi)步(bu)距(ju)誤差(cha)不會長期(qi)累積。

上面(mian)提到的都是(shi)在不失(shi)步的情況，如何才能失(shi)步呢(ni)?先(xian)我們需要知道造(zao)成電機失(shi)步的因素：

1、轉子(zi)加速度慢于步進電機的旋(xuan)轉磁場;

2、轉子的平均(jun)速度于(yu)定子磁(ci)場的平均(jun)旋轉速度;

3、電機負載慣性較(jiao)大(da);

4、步進電(dian)機(ji)產生共振。

  轉(zhuan)(zhuan)(zhuan)子(zi)加速度(du)慢于步(bu)進(jin)(jin)電(dian)(dian)(dian)機(ji)的(de)(de)旋轉(zhuan)(zhuan)(zhuan)磁(ci)場(chang)即(ji)轉(zhuan)(zhuan)(zhuan)子(zi)速度(du)低(di)于換(huan)相(xiang)速度(du)時(shi)，電(dian)(dian)(dian)機(ji)會(hui)產(chan)生(sheng)失(shi)步(bu)，這(zhe)是(shi)因為輸入電(dian)(dian)(dian)機(ji)的(de)(de)電(dian)(dian)(dian)能(neng)不足，產(chan)生(sheng)的(de)(de)力矩(ju)無法(fa)使(shi)轉(zhuan)(zhuan)(zhuan)子(zi)速度(du)跟(gen)上定子(zi)磁(ci)場(chang)的(de)(de)旋轉(zhuan)(zhuan)(zhuan)速度(du)，從而引起失(shi)步(bu)。轉(zhuan)(zhuan)(zhuan)子(zi)平(ping)均速度(du)于定子(zi)磁(ci)場(chang)平(ping)均旋轉(zhuan)(zhuan)(zhuan)速度(du)，這(zhe)是(shi)定子(zi)通電(dian)(dian)(dian)勵磁(ci)的(de)(de)時(shi)間較長(chang)，大于步(bu)進(jin)(jin)所需的(de)(de)時(shi)間，轉(zhuan)(zhuan)(zhuan)子(zi)在(zai)步(bu)進(jin)(jin)過(guo)程中獲(huo)得過(guo)多的(de)(de)能(neng)量，導致電(dian)(dian)(dian)機(ji)產(chan)生(sheng)的(de)(de)轉(zhuan)(zhuan)(zhuan)矩(ju)過(guo)大從而引起電(dian)(dian)(dian)機(ji)越(yue)步(bu)。

  以(yi)(yi)上導致步(bu)進電(dian)(dian)(dian)(dian)(dian)(dian)(dian)機(ji)失步(bu)的(de)(de)原因(yin)實(shi)質是(shi)步(bu)進傳(chuan)(chuan)(chuan)(chuan)動(dong)(dong)器(qi)選(xuan)擇(ze)不(bu)(bu)當而(er)導致，只有選(xuan)擇(ze)正確合適的(de)(de)步(bu)進傳(chuan)(chuan)(chuan)(chuan)動(dong)(dong)器(qi)才能(neng)使(shi)步(bu)進電(dian)(dian)(dian)(dian)(dian)(dian)(dian)機(ji)發(fa)揮其(qi)控制的(de)(de)特點。選(xuan)擇(ze)合適的(de)(de)傳(chuan)(chuan)(chuan)(chuan)動(dong)(dong)器(qi)需要(yao)根(gen)據電(dian)(dian)(dian)(dian)(dian)(dian)(dian)機(ji)的(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)，配用(yong)(yong)大于(yu)或等于(yu)此電(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)的(de)(de)傳(chuan)(chuan)(chuan)(chuan)動(dong)(dong)器(qi)。如果需要(yao)低振動(dong)(dong)或精度時，可配用(yong)(yong)細分型(xing)傳(chuan)(chuan)(chuan)(chuan)動(dong)(dong)器(qi)。對(dui)(dui)(dui)于(yu)大轉(zhuan)矩電(dian)(dian)(dian)(dian)(dian)(dian)(dian)機(ji)，盡可能(neng)用(yong)(yong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)型(xing)傳(chuan)(chuan)(chuan)(chuan)動(dong)(dong)器(qi)，以(yi)(yi)獲得良好(hao)的(de)(de)速性(xing)能(neng)。同時對(dui)(dui)(dui)于(yu)傳(chuan)(chuan)(chuan)(chuan)動(dong)(dong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)，很多人直(zhi)接使(shi)用(yong)(yong)開(kai)(kai)關(guan)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)作為傳(chuan)(chuan)(chuan)(chuan)動(dong)(dong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)，但是(shi)，一般好(hao)不(bu)(bu)要(yao)使(shi)用(yong)(yong)開(kai)(kai)關(guan)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)，特別是(shi)大力矩電(dian)(dian)(dian)(dian)(dian)(dian)(dian)機(ji)，除(chu)非選(xuan)用(yong)(yong)比需要(yao)的(de)(de)功(gong)率大一倍以(yi)(yi)上的(de)(de)開(kai)(kai)關(guan)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)。因(yin)為，電(dian)(dian)(dian)(dian)(dian)(dian)(dian)機(ji)工作時是(shi)大電(dian)(dian)(dian)(dian)(dian)(dian)(dian)感型(xing)負載(zai)，會對(dui)(dui)(dui)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)端形成瞬間的(de)(de)壓(ya)。而(er)開(kai)(kai)關(guan)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)的(de)(de)過載(zai)性(xing)能(neng)不(bu)(bu)好(hao)，會保護(hu)關(guan)斷(duan)，且其(qi)精密(mi)的(de)(de)穩壓(ya)性(xing)能(neng)又不(bu)(bu)需要(yao)，有時可能(neng)造成開(kai)(kai)關(guan)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)和傳(chuan)(chuan)(chuan)(chuan)動(dong)(dong)器(qi)的(de)(de)損壞。對(dui)(dui)(dui)于(yu)步(bu)進電(dian)(dian)(dian)(dian)(dian)(dian)(dian)機(ji)的(de)(de)傳(chuan)(chuan)(chuan)(chuan)動(dong)(dong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)，可以(yi)(yi)用(yong)(yong)常(chang)規(gui)的(de)(de)環形或R 型(xing)變(bian)壓(ya)器(qi)變(bian)壓(ya)的(de)(de)直(zhi)流(liu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)。 

  步進電(dian)機(ji)產(chan)生共(gong)振是因為電(dian)機(ji)接收的(de)(de)脈沖頻率(lv)等(deng)于(yu)步進電(dian)機(ji)的(de)(de)固有頻率(lv)，該(gai)頻率(lv)與傳動器(qi)的(de)(de)細(xi)分有關系。我(wo)們一般使用(yong)步進電(dian)機(ji)時，傳動器(qi)的(de)(de)細(xi)分能力很重要，共(gong)振范圍越(yue)小越(yue)好。對于(yu)電(dian)機(ji)負載慣性(xing)較大(da)是由于(yu)電(dian)機(ji)超載而引起，因此在使用(yong)時只需(xu)注意(yi)不要讓電(dian)機(ji)過(guo)載即可。