步進電機工作原理及實現方法
步進電(dian)(dian)動(dong)機(ji)(ji)是一種把電(dian)(dian)脈(mo)沖(chong)信號轉換(huan)成機(ji)(ji)械角位移的控制電(dian)(dian)機(ji)(ji)。所(suo)謂電脈(mo)沖(chong)，類(lei)似于(yu)脈(mo)搏，感受到脈(mo)搏跳動的(de)時候類(lei)似于(yu)脈(mo)沖(chong)的(de)高電平，不跳的(de)時候為低電平，這就是(shi)電脈(mo)沖(chong)信號。角位(wei)移(yi)單位(wei)是(shi)弧度。
步進電機的工作原理：
步進電機可分為反(fan)應式，永(yong)磁式，混合式。各(ge)有優(you)點，按實際(ji)需求選擇，反(fan)應式的(de)步距角(jiao)小(xiao)，精(jing)(jing)度高；永(yong)磁式的(de)力矩(ju)大。混合式的(de)具有精(jing)(jing)度高，力矩(ju)大的(de)特點，但成本高。下(xia)面以反(fan)應式為例(li)說明步進電機的(de)結構和工作(zuo)原理。
定(ding)子(zi)和(he)轉子(zi)。定(ding)子(zi)和(he)轉子(zi)在學過直流電機(ji)后就不陌生了。但是，步(bu)進電機(ji)以(yi)三(san)相(xiang)的為例，其(qi)定(ding)子(zi)和(he)轉子(zi)上(shang)分別有六個(ge)、四個(ge)磁極(ji) 。上(shang)圖中，A與A'組成一相(xiang)；B與B'為一相(xiang)；C與C'為一相(xiang)。所以(yi)此步(bu)進電機(ji)為三(san)相(xiang)步(bu)進電機(ji)。
所(suo)以，步進電(dian)(dian)(dian)(dian)(dian)機(ji)(ji)(ji)是靠(kao)脈(mo)(mo)(mo)沖(chong)(chong)數(shu)(shu)量來轉(zhuan)(zhuan)(zhuan)動(dong)的(de)(de)(de)(de)，需要(yao)轉(zhuan)(zhuan)(zhuan)多少圈就(jiu)(jiu)給相應個數(shu)(shu)的(de)(de)(de)(de)脈(mo)(mo)(mo)沖(chong)(chong)數(shu)(shu)。因此(ci)，步進電(dian)(dian)(dian)(dian)(dian)機(ji)(ji)(ji)能夠(gou)達到準確定位的(de)(de)(de)(de)目的(de)(de)(de)(de)；同時可以通過控(kong)(kong)制(zhi)(zhi)(zhi)脈(mo)(mo)(mo)沖(chong)(chong)頻(pin)率來控(kong)(kong)制(zhi)(zhi)(zhi)電(dian)(dian)(dian)(dian)(dian)機(ji)(ji)(ji)轉(zhuan)(zhuan)(zhuan)動(dong)的(de)(de)(de)(de)速度和加速度，也就(jiu)(jiu)是控(kong)(kong)制(zhi)(zhi)(zhi)多長時間給一個脈(mo)(mo)(mo)沖(chong)(chong)，從而達到調速的(de)(de)(de)(de)目的(de)(de)(de)(de)。每(mei)輸(shu)入一個電(dian)(dian)(dian)(dian)(dian)脈(mo)(mo)(mo)沖(chong)(chong)，電(dian)(dian)(dian)(dian)(dian)動(dong)機(ji)(ji)(ji)轉(zhuan)(zhuan)(zhuan)動(dong)一個角度前進一步。它(ta)輸(shu)出的(de)(de)(de)(de)角位移(yi)與輸(shu)入的(de)(de)(de)(de)脈(mo)(mo)(mo)沖(chong)(chong)數(shu)(shu)成正(zheng)比(bi)(bi)、轉(zhuan)(zhuan)(zhuan)速與脈(mo)(mo)(mo)沖(chong)(chong)頻(pin)率成正(zheng)比(bi)(bi)。改變繞(rao)組通電(dian)(dian)(dian)(dian)(dian)的(de)(de)(de)(de)順(shun)序(xu)，控(kong)(kong)制(zhi)(zhi)(zhi)電(dian)(dian)(dian)(dian)(dian)機(ji)(ji)(ji)正(zheng)反轉(zhuan)(zhuan)(zhuan)。即(ji)如果按(an)照(zhao)A、B、C相的(de)(de)(de)(de)通電(dian)(dian)(dian)(dian)(dian)順(shun)序(xu)為正(zheng)轉(zhuan)(zhuan)(zhuan)，那么按(an)照(zhao)C、B、A相的(de)(de)(de)(de)順(shun)序(xu)通電(dian)(dian)(dian)(dian)(dian)則電(dian)(dian)(dian)(dian)(dian)機(ji)(ji)(ji)就(jiu)(jiu)會反轉(zhuan)(zhuan)(zhuan)。所(suo)以可用控(kong)(kong)制(zhi)(zhi)(zhi)脈(mo)(mo)(mo)沖(chong)(chong)數(shu)(shu)量、頻(pin)率及(ji)電(dian)(dian)(dian)(dian)(dian)動(dong)機(ji)(ji)(ji)各相繞(rao)組的(de)(de)(de)(de)通電(dian)(dian)(dian)(dian)(dian)順(shun)序(xu)來控(kong)(kong)制(zhi)(zhi)(zhi)步進電(dian)(dian)(dian)(dian)(dian)機(ji)(ji)(ji)的(de)(de)(de)(de)轉(zhuan)(zhuan)(zhuan)動(dong)。
實現方法：
通過對直流(liu)電(dian)(dian)機(ji)的(de)學習，我們知道(dao)，電(dian)(dian)機(ji)是(shi)電(dian)(dian)流(liu)驅(qu)(qu)(qu)(qu)動(dong)(dong)的(de)元件，需要大電(dian)(dian)流(liu)才(cai)能(neng)工作(zuo)。步(bu)(bu)(bu)進(jin)(jin)電(dian)(dian)機(ji)依然(ran)。而單片(pian)(pian)機(ji)輸出口的(de)驅(qu)(qu)(qu)(qu)動(dong)(dong)能(neng)力是(shi)遠(yuan)遠(yuan)不(bu)夠的(de)，也需要借助(zhu)另一個元件來(lai)實現對步(bu)(bu)(bu)進(jin)(jin)電(dian)(dian)機(ji)的(de)控(kong)制(zhi)。另一個元件即為(wei)(wei)步(bu)(bu)(bu)進(jin)(jin)電(dian)(dian)機(ji)驅(qu)(qu)(qu)(qu)動(dong)(dong)控(kong)制(zhi)器(qi)。單片(pian)(pian)機(ji)通過控(kong)制(zhi)驅(qu)(qu)(qu)(qu)動(dong)(dong)器(qi)來(lai)間接的(de)控(kong)制(zhi)步(bu)(bu)(bu)進(jin)(jin)電(dian)(dian)機(ji)。這里我們以四(si)相(xiang)五線制(zhi)步(bu)(bu)(bu)進(jin)(jin)電(dian)(dian)機(ji)為(wei)(wei)例，驅(qu)(qu)(qu)(qu)動(dong)(dong)器(qi)選擇熟悉的(de)ULN2003元件，在此(ci)也是(shi)放大驅(qu)(qu)(qu)(qu)動(dong)(dong)電(dian)(dian)流(liu)的(de)作(zuo)用(yong)。該芯片(pian)(pian)多可一次(ci)驅(qu)(qu)(qu)(qu)動(dong)(dong)八線步(bu)(bu)(bu)進(jin)(jin)電(dian)(dian)機(ji)。實例中采用(yong)的(de)是(shi)四(si)相(xiang)無線制(zhi)24BYJ-48步(bu)(bu)(bu)進(jin)(jin)電(dian)(dian)機(ji)，驅(qu)(qu)(qu)(qu)動(dong)(dong)電(dian)(dian)壓(ya)為(wei)(wei)5V，驅(qu)(qu)(qu)(qu)動(dong)(dong)方式為(wei)(wei)四(si)相(xiang)四(si)拍。
