一、電動車電機的工作原理
電動車電機是(shi)把電(dian)能轉換成機(ji)械能的(de)一(yi)種設備。它是(shi)利用(yong)通電(dian)線圈(也就是(shi)定(ding)子繞組(zu))產生旋(xuan)轉磁(ci)場并作用(yong)于轉子鼠籠式式閉合鋁框(kuang)形成磁(ci)電(dian)動力旋(xuan)轉扭矩。
電(dian)(dian)(dian)動車電(dian)(dian)(dian)機(ji)(ji)按使用(yong)電(dian)(dian)(dian)源不同(tong)分為直流電(dian)(dian)(dian)動機(ji)(ji)和交(jiao)流電(dian)(dian)(dian)動機(ji)(ji),電(dian)(dian)(dian)力系統中(zhong)的(de)電(dian)(dian)(dian)動機(ji)(ji)大部分是(shi)交(jiao)流電(dian)(dian)(dian)機(ji)(ji),可以(yi)是(shi)同(tong)步(bu)電(dian)(dian)(dian)機(ji)(ji)或者是(shi)異步(bu)電(dian)(dian)(dian)機(ji)(ji)(電(dian)(dian)(dian)機(ji)(ji)定(ding)子(zi)磁(ci)場(chang)轉速與(yu)轉子(zi)旋(xuan)轉轉速不保持同(tong)步(bu)速)。電(dian)(dian)(dian)動機(ji)(ji)主要由(you)定(ding)子(zi)與(yu)轉子(zi)組成,通電(dian)(dian)(dian)導線在(zai)磁(ci)場(chang)中(zhong)受力運動的(de)方向跟電(dian)(dian)(dian)流方向和磁(ci)感(gan)線(磁(ci)場(chang)方向)方向有(you)關。電(dian)(dian)(dian)動機(ji)(ji)工(gong)作原(yuan)理是(shi)磁(ci)場(chang)對電(dian)(dian)(dian)流受力的(de)作用(yong),使電(dian)(dian)(dian)動機(ji)(ji)轉動。
二、電動車電機的組成結構
電動車電機普(pu)遍采用(yong)永磁直流電(dian)機(ji)(ji)(ji)。電(dian)動車電(dian)機(ji)(ji)(ji)按照(zhao)電(dian)機(ji)(ji)(ji)的(de)通電(dian)形(xing)式(shi)來分,可分為有刷電(dian)機(ji)(ji)(ji)和無(wu)刷電(dian)機(ji)(ji)(ji)兩大類(lei);按照(zhao)電(dian)機(ji)(ji)(ji)總成的(de)機(ji)(ji)(ji)械結構來分,一般分為“有齒(chi)”(電(dian)機(ji)(ji)(ji)轉速(su)高,需要經(jing)過齒(chi)輪減(jian)速(su))和“無(wu)齒(chi)”(電(dian)機(ji)(ji)(ji)扭矩(ju)輸(shu)出不(bu)經(jing)過任何減(jian)速(su))兩大類(lei)。
1、永磁式直流電機
由定子(zi)磁極、轉子(zi)、電(dian)刷、外殼等(deng)組(zu)成。
定子磁極采(cai)用永磁體(ti)(永久磁鋼),有鐵氧體(ti)、鋁(lv)鎳鈷、釹鐵硼等材料。按(an)其結構(gou)形式可分為圓筒(tong)型和瓦(wa)塊型等幾種。
轉子一般采(cai)用(yong)硅鋼片疊壓而成(cheng),漆包線繞在轉子鐵心的(de)(de)兩槽之間(jian)(三槽即有(you)三個繞組),其各接(jie)頭分(fen)別(bie)焊在換向器的(de)(de)金屬(shu)片上。
電(dian)(dian)刷是連接電(dian)(dian)源與(yu)(yu)轉子(zi)繞組的導電(dian)(dian)部件,具備導電(dian)(dian)與(yu)(yu)耐磨(mo)兩種(zhong)性能。永磁電(dian)(dian)機的電(dian)(dian)刷使(shi)用單(dan)性金屬片或金屬石墨電(dian)(dian)刷、電(dian)(dian)化石墨電(dian)(dian)刷。
2、無刷直流電機
由永(yong)磁體轉子(zi)、多(duo)極繞組(zu)定子(zi)、位置傳感(gan)器等(deng)(deng)組(zu)成。無刷直流電(dian)(dian)(dian)機的特點是無刷,采用半導(dao)體開(kai)關(guan)(guan)器件(如霍爾元件)來實現電(dian)(dian)(dian)子(zi)換(huan)(huan)向(xiang)的,即用電(dian)(dian)(dian)子(zi)開(kai)關(guan)(guan)器件代替傳統的接觸式(shi)換(huan)(huan)向(xiang)器和電(dian)(dian)(dian)刷。它具有可(ke)靠性高(gao)、無換(huan)(huan)向(xiang)火花、機械噪聲低等(deng)(deng)優點。如圖1所示。
位(wei)置(zhi)(zhi)傳(chuan)(chuan)感器按轉子(zi)位(wei)置(zhi)(zhi)的變化,沿著一定(ding)次(ci)序對定(ding)子(zi)繞(rao)組的電流進行(xing)換流(即檢測轉子(zi)磁極相對定(ding)子(zi)繞(rao)組的位(wei)置(zhi)(zhi),并在確(que)定(ding)的位(wei)置(zhi)(zhi)處(chu)(chu)產生位(wei)置(zhi)(zhi)傳(chuan)(chuan)感信(xin)號(hao),經信(xin)號(hao)轉換電路處(chu)(chu)理后去控制功(gong)率開關電路,按一定(ding)的邏輯關系進行(xing)繞(rao)組電流切換)。
3、高速永磁無刷電機
由(you)定子(zi)鐵(tie)心、磁鋼(gang)轉子(zi)、太(tai)陽輪、減速離合器(qi)、輪轂外(wai)殼等組成。
電機(ji)蓋(gai)子(zi)上(shang)面可以(yi)裝上(shang)霍爾(er)傳感器,用以(yi)測速。
位置傳感(gan)器有磁敏式、光電式和電磁式三種(zhong)類(lei)型。
采用磁(ci)敏(min)式位置傳感器的無刷直流電(dian)動(dong)機(ji),其磁(ci)敏(min)傳感器件(jian)(例如霍爾元(yuan)件(jian)、磁(ci)敏(min)二極管、磁(ci)敏(min)詁極管、磁(ci)敏(min)電(dian)阻器或(huo)專用集成(cheng)電(dian)路等)裝在定子組(zu)件(jian)上,用來檢測永磁(ci)體、轉子旋轉時產生(sheng)的磁(ci)場變化(hua)。電(dian)動(dong)汽車多用的是霍爾元(yuan)件(jian)。
采用(yong)光(guang)(guang)(guang)電(dian)(dian)式位置(zhi)傳感(gan)器(qi)的(de)無刷(shua)直(zhi)流電(dian)(dian)動機(ji),在定子(zi)(zi)組件上按(an)一(yi)定位置(zhi)配置(zhi)了光(guang)(guang)(guang)電(dian)(dian)傳感(gan)器(qi)件,轉(zhuan)子(zi)(zi)上裝有(you)遮(zhe)(zhe)光(guang)(guang)(guang)板,光(guang)(guang)(guang)源為發(fa)光(guang)(guang)(guang)二極(ji)管或小燈泡。轉(zhuan)子(zi)(zi)旋轉(zhuan)時,由于遮(zhe)(zhe)光(guang)(guang)(guang)板的(de)作(zuo)用(yong),定子(zi)(zi)上的(de)光(guang)(guang)(guang)敏元器(qi)件將會按(an)一(yi)定頻率間(jian)歇間(jian)生(sheng)脈沖信號。
采用電(dian)磁(ci)(ci)式位置傳感器的無(wu)刷(shua)直流電(dian)動機,是在定(ding)子(zi)(zi)組件(jian)上(shang)安裝有電(dian)磁(ci)(ci)傳感器部件(jian)(例如(ru)耦合變(bian)壓(ya)器、接(jie)近(jin)開關、LC諧(xie)振電(dian)路等(deng)),當永磁(ci)(ci)體轉(zhuan)子(zi)(zi)位置發生變(bian)化(hua)時,電(dian)磁(ci)(ci)效應將使電(dian)磁(ci)(ci)傳感器產生高頻調制信號(其幅值隨(sui)轉(zhuan)子(zi)(zi)位置而變(bian)化(hua))。
定子繞(rao)組的(de)工作電壓(ya)由位置傳感器輸出控制的(de)電子開(kai)關電路提供。