一、電動車電機的工作原理
電動車電機是把電能轉換成(cheng)機械能的(de)一種設備。它是利(li)用(yong)通電線(xian)圈(也(ye)就是定(ding)子(zi)繞(rao)組)產生旋(xuan)轉磁(ci)(ci)場并作用(yong)于(yu)轉子(zi)鼠(shu)籠式式閉合鋁框(kuang)形(xing)成(cheng)磁(ci)(ci)電動力旋(xuan)轉扭(niu)矩(ju)。
電(dian)(dian)(dian)(dian)動(dong)車電(dian)(dian)(dian)(dian)機按使用電(dian)(dian)(dian)(dian)源不(bu)同分為(wei)直流(liu)電(dian)(dian)(dian)(dian)動(dong)機和(he)交(jiao)流(liu)電(dian)(dian)(dian)(dian)動(dong)機,電(dian)(dian)(dian)(dian)力(li)系(xi)統中(zhong)的電(dian)(dian)(dian)(dian)動(dong)機大部分是(shi)交(jiao)流(liu)電(dian)(dian)(dian)(dian)機,可以是(shi)同步電(dian)(dian)(dian)(dian)機或者是(shi)異步電(dian)(dian)(dian)(dian)機(電(dian)(dian)(dian)(dian)機定(ding)子(zi)磁(ci)場(chang)(chang)轉(zhuan)(zhuan)速與(yu)轉(zhuan)(zhuan)子(zi)旋轉(zhuan)(zhuan)轉(zhuan)(zhuan)速不(bu)保持同步速)。電(dian)(dian)(dian)(dian)動(dong)機主(zhu)要由定(ding)子(zi)與(yu)轉(zhuan)(zhuan)子(zi)組成(cheng),通電(dian)(dian)(dian)(dian)導線在磁(ci)場(chang)(chang)中(zhong)受力(li)運動(dong)的方(fang)向(xiang)跟電(dian)(dian)(dian)(dian)流(liu)方(fang)向(xiang)和(he)磁(ci)感線(磁(ci)場(chang)(chang)方(fang)向(xiang))方(fang)向(xiang)有(you)關。電(dian)(dian)(dian)(dian)動(dong)機工(gong)作原理是(shi)磁(ci)場(chang)(chang)對電(dian)(dian)(dian)(dian)流(liu)受力(li)的作用,使電(dian)(dian)(dian)(dian)動(dong)機轉(zhuan)(zhuan)動(dong)。
二、電動車電機的組成結構
電動車電機普遍采用永(yong)磁(ci)直流電(dian)(dian)機(ji)(ji)。電(dian)(dian)動車電(dian)(dian)機(ji)(ji)按照電(dian)(dian)機(ji)(ji)的(de)通電(dian)(dian)形式來分(fen),可分(fen)為(wei)有(you)刷(shua)電(dian)(dian)機(ji)(ji)和無刷(shua)電(dian)(dian)機(ji)(ji)兩大類;按照電(dian)(dian)機(ji)(ji)總成(cheng)的(de)機(ji)(ji)械(xie)結(jie)構來分(fen),一般分(fen)為(wei)“有(you)齒(chi)”(電(dian)(dian)機(ji)(ji)轉速(su)高,需(xu)要經(jing)過齒(chi)輪(lun)減(jian)速(su))和“無齒(chi)”(電(dian)(dian)機(ji)(ji)扭(niu)矩輸出不(bu)經(jing)過任何減(jian)速(su))兩大類。
1、永磁式直流電機
由定子磁極(ji)、轉子、電刷(shua)、外(wai)殼等組成。
定子(zi)磁(ci)極采用永磁(ci)體(ti)(永久磁(ci)鋼),有鐵(tie)氧體(ti)、鋁鎳鈷、釹鐵(tie)硼(peng)等(deng)材料。按(an)其結構形式可分為圓筒型(xing)和(he)瓦(wa)塊型(xing)等(deng)幾種。
轉子一(yi)般采用(yong)硅鋼(gang)片(pian)疊壓而(er)成,漆包線繞在(zai)轉子鐵心的(de)(de)兩槽之間(三(san)槽即有三(san)個繞組),其各(ge)接頭(tou)分(fen)別焊在(zai)換向器的(de)(de)金屬片(pian)上(shang)。
電(dian)(dian)刷(shua)是連接(jie)電(dian)(dian)源與轉子繞組的導電(dian)(dian)部件(jian),具備導電(dian)(dian)與耐磨兩(liang)種性能。永磁電(dian)(dian)機的電(dian)(dian)刷(shua)使用單性金屬(shu)片或金屬(shu)石墨(mo)電(dian)(dian)刷(shua)、電(dian)(dian)化石墨(mo)電(dian)(dian)刷(shua)。
2、無刷直流電機
由永磁(ci)體轉子、多極繞組定子、位置傳(chuan)感器等(deng)組成。無(wu)(wu)刷(shua)直(zhi)流電(dian)(dian)(dian)機(ji)的(de)特(te)點是無(wu)(wu)刷(shua),采(cai)用(yong)半導體開(kai)關(guan)器件(如霍爾元件)來實現電(dian)(dian)(dian)子換(huan)(huan)向(xiang)的(de),即用(yong)電(dian)(dian)(dian)子開(kai)關(guan)器件代(dai)替(ti)傳(chuan)統(tong)的(de)接觸式換(huan)(huan)向(xiang)器和電(dian)(dian)(dian)刷(shua)。它(ta)具(ju)有可靠性高、無(wu)(wu)換(huan)(huan)向(xiang)火花、機(ji)械噪(zao)聲(sheng)低等(deng)優(you)點。如圖1所示。
位(wei)(wei)置(zhi)傳(chuan)感器按轉子位(wei)(wei)置(zhi)的(de)變(bian)化,沿著一定次序對定子繞組的(de)電流進行換流(即檢測轉子磁極(ji)相對定子繞組的(de)位(wei)(wei)置(zhi),并在確定的(de)位(wei)(wei)置(zhi)處產生位(wei)(wei)置(zhi)傳(chuan)感信(xin)號,經信(xin)號轉換電路處理后去控制功率開關(guan)電路,按一定的(de)邏輯(ji)關(guan)系(xi)進行繞組電流切(qie)換)。
3、高速永磁無刷電機
由定子鐵心、磁鋼轉子、太陽輪(lun)、減速離合器、輪(lun)轂外殼等組(zu)成(cheng)。
電機(ji)蓋(gai)子上面可以裝上霍爾傳感器(qi),用以測速(su)。
位置(zhi)傳感器(qi)有磁敏式(shi)、光電式(shi)和(he)電磁式(shi)三種類型(xing)。
采用(yong)磁(ci)敏式位置傳感器(qi)的(de)無刷直(zhi)流電動機,其磁(ci)敏傳感器(qi)件(例如霍爾(er)元件、磁(ci)敏二極(ji)管(guan)、磁(ci)敏詁極(ji)管(guan)、磁(ci)敏電阻(zu)器(qi)或專用(yong)集成電路等)裝在定(ding)子組件上(shang),用(yong)來檢測永磁(ci)體、轉子旋轉時產生(sheng)的(de)磁(ci)場(chang)變化。電動汽車多用(yong)的(de)是霍爾(er)元件。
采用(yong)光(guang)電式位置傳(chuan)感(gan)器(qi)的無刷直流電動(dong)機,在定(ding)(ding)子組件(jian)上(shang)(shang)按一定(ding)(ding)位置配置了光(guang)電傳(chuan)感(gan)器(qi)件(jian),轉子上(shang)(shang)裝有遮(zhe)(zhe)光(guang)板(ban),光(guang)源為(wei)發(fa)光(guang)二(er)極(ji)管或小燈泡。轉子旋轉時,由于遮(zhe)(zhe)光(guang)板(ban)的作用(yong),定(ding)(ding)子上(shang)(shang)的光(guang)敏(min)元(yuan)器(qi)件(jian)將(jiang)會按一定(ding)(ding)頻率(lv)間(jian)歇間(jian)生脈沖信號(hao)。
采用電(dian)磁(ci)(ci)(ci)式位(wei)置傳(chuan)感器(qi)的無刷(shua)直流(liu)電(dian)動機,是在定(ding)子(zi)組(zu)件上安(an)裝有電(dian)磁(ci)(ci)(ci)傳(chuan)感器(qi)部件(例如耦合變壓器(qi)、接近開關、LC諧(xie)振電(dian)路等(deng)),當永磁(ci)(ci)(ci)體(ti)轉子(zi)位(wei)置發生(sheng)變化時,電(dian)磁(ci)(ci)(ci)效應(ying)將使電(dian)磁(ci)(ci)(ci)傳(chuan)感器(qi)產生(sheng)高頻調制信號(其幅值隨轉子(zi)位(wei)置而變化)。
定子繞(rao)組的工作電(dian)壓由(you)位置(zhi)傳感器輸出控(kong)制的電(dian)子開關電(dian)路提供(gong)。