【直流電動(dong)機(ji)】直流電動(dong)機(ji)工作原理 直流電動(dong)機(ji)和交流電動(dong)機(ji)區(qu)別

直流電動機工作原理

直流電機是根(gen)據通(tong)電(dian)(dian)流(liu)(liu)(liu)的(de)導體(ti)在(zai)(zai)磁場(chang)(chang)中(zhong)會(hui)受(shou)力(li)(li)的(de)原理來工作的(de)。既電(dian)(dian)工基礎(chu)中(zhong)的(de)左手定(ding)則。電(dian)(dian)動(dong)機(ji)的(de)轉(zhuan)子(zi)上(shang)繞有線圈，通(tong)入電(dian)(dian)流(liu)(liu)(liu)，定(ding)子(zi)作為(wei)磁場(chang)(chang)線圈也(ye)通(tong)入電(dian)(dian)流(liu)(liu)(liu)，產生定(ding)子(zi)磁場(chang)(chang)，通(tong)電(dian)(dian)流(liu)(liu)(liu)的(de)轉(zhuan)子(zi)線圈在(zai)(zai)定(ding)子(zi)磁場(chang)(chang)中(zhong)，就會(hui)產生電(dian)(dian)動(dong)力(li)(li)，推動(dong)轉(zhuan)子(zi)旋轉(zhuan)。轉(zhuan)子(zi)電(dian)(dian)流(liu)(liu)(liu)是通(tong)過整流(liu)(liu)(liu)子(zi)上(shang)的(de)碳刷(shua)連(lian)接到(dao)直流(liu)(liu)(liu)電(dian)(dian)源的(de)。

直(zhi)流無(wu)刷電(dian)機(ji)的(de)控(kong)制(zhi)(zhi)原理，要(yao)讓(rang)電(dian)機(ji)轉(zhuan)(zhuan)(zhuan)動(dong)起(qi)來，首先(xian)控(kong)制(zhi)(zhi)部就(jiu)必須(xu)根據(ju)hall-sensor感應到的(de)電(dian)機(ji)轉(zhuan)(zhuan)(zhuan)子(zi)(zi)(zi)所在(zai)位(wei)置(zhi)，然后(hou)依(yi)照定子(zi)(zi)(zi)繞線決定開(kai)啟(qi)(qi)(qi)(或(huo)關(guan)閉(bi))換流器(inverter)中(zhong)功(gong)率晶(jing)(jing)體(ti)管(guan)的(de)順(shun)序，inverter中(zhong)之AH、BH、CH(這些(xie)稱為(wei)上臂功(gong)率晶(jing)(jing)體(ti)管(guan))及AL、BL、CL(這些(xie)稱為(wei)下臂功(gong)率晶(jing)(jing)體(ti)管(guan))，使電(dian)流依(yi)序流經電(dian)機(ji)線圈產(chan)生順(shun)向(xiang)(或(huo)逆向(xiang))旋轉(zhuan)(zhuan)(zhuan)磁場，并(bing)與轉(zhuan)(zhuan)(zhuan)子(zi)(zi)(zi)的(de)磁鐵相(xiang)互(hu)作用，如此(ci)就(jiu)能使電(dian)機(ji)順(shun)時(shi)/逆時(shi)轉(zhuan)(zhuan)(zhuan)動(dong)。當電(dian)機(ji)轉(zhuan)(zhuan)(zhuan)子(zi)(zi)(zi)轉(zhuan)(zhuan)(zhuan)動(dong)到hall-sensor感應出另一組信號的(de)位(wei)置(zhi)時(shi)，控(kong)制(zhi)(zhi)部又再開(kai)啟(qi)(qi)(qi)下一組功(gong)率晶(jing)(jing)體(ti)管(guan)，如此(ci)循環電(dian)機(ji)就(jiu)可以依(yi)同(tong)一方向(xiang)繼(ji)續轉(zhuan)(zhuan)(zhuan)動(dong)直(zhi)到控(kong)制(zhi)(zhi)部決定要(yao)電(dian)機(ji)轉(zhuan)(zhuan)(zhuan)子(zi)(zi)(zi)停止(zhi)則關(guan)閉(bi)功(gong)率晶(jing)(jing)體(ti)管(guan)(或(huo)只(zhi)開(kai)下臂功(gong)率晶(jing)(jing)體(ti)管(guan))；要(yao)電(dian)機(ji)轉(zhuan)(zhuan)(zhuan)子(zi)(zi)(zi)反向(xiang)則功(gong)率晶(jing)(jing)體(ti)管(guan)開(kai)啟(qi)(qi)(qi)順(shun)序相(xiang)反。

基本上(shang)(shang)功率(lv)晶(jing)體(ti)管的開(kai)法可舉(ju)例(li)如下：AH、BL一組(zu)(zu)→AH、CL一組(zu)(zu)→BH、CL一組(zu)(zu)→BH、AL一組(zu)(zu)→CH、AL一組(zu)(zu)→CH、BL一組(zu)(zu)，但絕(jue)不能開(kai)成(cheng)AH、AL或(huo)BH、BL或(huo)CH、CL。此(ci)外因為(wei)電子零(ling)件(jian)總有開(kai)關(guan)的響(xiang)(xiang)應時(shi)間，所以(yi)功率(lv)晶(jing)體(ti)管在(zai)關(guan)與開(kai)的交錯時(shi)間要將零(ling)件(jian)的響(xiang)(xiang)應時(shi)間考慮進(jin)去，否則當上(shang)(shang)臂(bei)(或(huo)下臂(bei))尚未(wei)完全(quan)關(guan)閉，下臂(bei)(或(huo)上(shang)(shang)臂(bei))就(jiu)已開(kai)啟，結果(guo)就(jiu)造成(cheng)上(shang)(shang)、下臂(bei)短路而使(shi)功率(lv)晶(jing)體(ti)管燒毀。

當電機(ji)轉動(dong)起來，控(kong)制(zhi)部會再根據驅動(dong)器設定(ding)的速(su)度(du)及加/減速(su)率所組(zu)成(cheng)的命令(Command)與hall-sensor信號變化的速(su)度(du)加以比對(或(huo)由(you)軟件運算)再來決定(ding)由(you)下一(yi)組(zu)(AH、BL或(huo)AH、CL或(huo)BH、CL或(huo)……)開關導通，以及導通時間(jian)長(chang)短。速(su)度(du)不(bu)夠則(ze)開長(chang)，速(su)度(du)過頭則(ze)減短，此部份工作就由(you)PWM來完(wan)成(cheng)。PWM是決定(ding)電機(ji)轉速(su)快或(huo)慢的方式，如何(he)產(chan)生這樣(yang)的PWM才是要(yao)達到較(jiao)精(jing)準速(su)度(du)控(kong)制(zhi)的核心(xin)。

高(gao)轉(zhuan)速的(de)速度(du)(du)控(kong)(kong)(kong)制(zhi)(zhi)(zhi)(zhi)(zhi)(zhi)(zhi)必須考慮到(dao)(dao)系統的(de)CLOCK 分辨率(lv)是否足以(yi)掌(zhang)握處(chu)理(li)(li)(li)軟(ruan)件指令的(de)時(shi)間，另外對于hall-sensor信號變(bian)化的(de)資料(liao)存取方(fang)式也影(ying)響到(dao)(dao)處(chu)理(li)(li)(li)器效(xiao)能(neng)(neng)與判定正(zheng)確性(xing)、實時(shi)性(xing)。至于低轉(zhuan)速的(de)速度(du)(du)控(kong)(kong)(kong)制(zhi)(zhi)(zhi)(zhi)(zhi)(zhi)(zhi)尤(you)其是低速起動則因(yin)為回(hui)(hui)傳的(de)hall-sensor信號變(bian)化變(bian)得更慢(man)，怎樣擷取信號方(fang)式、處(chu)理(li)(li)(li)時(shi)機(ji)以(yi)及根據電(dian)(dian)機(ji)特性(xing)適(shi)當(dang)配置(zhi)控(kong)(kong)(kong)制(zhi)(zhi)(zhi)(zhi)(zhi)(zhi)(zhi)參數(shu)值就(jiu)顯得非常重要(yao)。或者速度(du)(du)回(hui)(hui)傳改(gai)變(bian)以(yi)encoder變(bian)化為參考，使信號分辨率(lv)增加以(yi)期得到(dao)(dao)更佳(jia)的(de)控(kong)(kong)(kong)制(zhi)(zhi)(zhi)(zhi)(zhi)(zhi)(zhi)。電(dian)(dian)機(ji)能(neng)(neng)夠運(yun)轉(zhuan)順暢而(er)且響應良好，P.I.D.控(kong)(kong)(kong)制(zhi)(zhi)(zhi)(zhi)(zhi)(zhi)(zhi)的(de)恰當(dang)與否也無法忽視。之前提到(dao)(dao)直流無刷電(dian)(dian)機(ji)是閉回(hui)(hui)路控(kong)(kong)(kong)制(zhi)(zhi)(zhi)(zhi)(zhi)(zhi)(zhi)，因(yin)此回(hui)(hui)授信號就(jiu)等于是告訴控(kong)(kong)(kong)制(zhi)(zhi)(zhi)(zhi)(zhi)(zhi)(zhi)部電(dian)(dian)機(ji)轉(zhuan)速距離目(mu)標速度(du)(du)還差(cha)多(duo)少，這就(jiu)是誤差(cha)(Error)。知道了誤差(cha)自然(ran)就(jiu)要(yao)補償，方(fang)式有傳統的(de)工(gong)程控(kong)(kong)(kong)制(zhi)(zhi)(zhi)(zhi)(zhi)(zhi)(zhi)如P.I.D.控(kong)(kong)(kong)制(zhi)(zhi)(zhi)(zhi)(zhi)(zhi)(zhi)。但控(kong)(kong)(kong)制(zhi)(zhi)(zhi)(zhi)(zhi)(zhi)(zhi)的(de)狀態及環境其實是復雜多(duo)變(bian)的(de)，若要(yao)控(kong)(kong)(kong)制(zhi)(zhi)(zhi)(zhi)(zhi)(zhi)(zhi)的(de)堅固耐用則要(yao)考慮的(de)因(yin)素恐怕不是傳統的(de)工(gong)程控(kong)(kong)(kong)制(zhi)(zhi)(zhi)(zhi)(zhi)(zhi)(zhi)能(neng)(neng)完(wan)全掌(zhang)握，所以(yi)模糊控(kong)(kong)(kong)制(zhi)(zhi)(zhi)(zhi)(zhi)(zhi)(zhi)、專家系統及神經(jing)網絡也將(jiang)被納入成(cheng)為智(zhi)能(neng)(neng)型P.I.D.控(kong)(kong)(kong)制(zhi)(zhi)(zhi)(zhi)(zhi)(zhi)(zhi)的(de)重要(yao)理(li)(li)(li)論(lun)。

直流電動機和交流電動機區別

從結構上說，直流(liu)(liu)電(dian)機的(de)原理(li)相(xiang)對簡單，但結構復(fu)雜(za)，不便于(yu)維護。而(er)交流(liu)(liu)電(dian)機原理(li)復(fu)雜(za)但結構相(xiang)對簡單，而(er)且(qie)比直流(liu)(liu)電(dian)機便于(yu)維護。

直流電機(ji)是通過(guo)電刷和換向(xiang)器把電流引入(ru)轉(zhuan)(zhuan)子(zi)電樞中(zhong)，從(cong)而使轉(zhuan)(zhuan)子(zi)在定(ding)子(zi)磁場中(zhong)受(shou)力而產(chan)生旋(xuan)轉(zhuan)(zhuan)。交流電機(ji)（以常用的交流異步電動機(ji)為(wei)例）是把交流電通入(ru)定(ding)子(zi)繞(rao)組，從(cong)而在定(ding)轉(zhuan)(zhuan)子(zi)氣隙中(zhong)產(chan)生旋(xuan)轉(zhuan)(zhuan)磁場，旋(xuan)轉(zhuan)(zhuan)磁場在轉(zhuan)(zhuan)子(zi)繞(rao)組中(zhong)產(chan)生感(gan)應(ying)電流，進(jin)而使轉(zhuan)(zhuan)子(zi)在定(ding)子(zi)磁場中(zhong)受(shou)力產(chan)生旋(xuan)轉(zhuan)(zhuan)。

1、直流特點：

（一(yi)）調速(su)性能好(hao)。所(suo)謂“調速(su)性能”，是(shi)指電動(dong)機在(zai)一(yi)定(ding)負載(zai)的條件(jian)下，根據需(xu)要，人為(wei)地(di)改變電動(dong)機的轉速(su)。直(zhi)流電動(dong)機可以在(zai)重負載(zai)條件(jian)下，實現(xian)均勻、平滑的無(wu)級(ji)調速(su)，而且調速(su)范圍較寬。

（二）起動力矩(ju)大。可以均(jun)勻(yun)而(er)經濟地實現轉速調節。因此，凡是在重負(fu)載下起動或要(yao)求(qiu)均(jun)勻(yun)調節轉速的機械。

例(li)如(ru)大型(xing)可逆軋鋼(gang)機(ji)、卷揚機(ji)、電(dian)力機(ji)車(che)、電(dian)車(che)等，都用直流直流電(dian)動機(ji)電(dian)動機(ji)拖動。

2、交流特點：

交(jiao)流電(dian)動機的工作效率較(jiao)高(gao)，又沒有(you)煙塵、氣(qi)味，不污染環境，噪聲也(ye)較(jiao)小。由于(yu)它的一系列優點，所(suo)以在工農業(ye)生產、交(jiao)通(tong)運(yun)輸、國防、商業(ye)及(ji)家用電(dian)器、醫(yi)療電(dian)器設備等各方面廣泛(fan)應(ying)用。