一、電動車電機的工作原理
電動車電機是(shi)把(ba)電(dian)能轉(zhuan)換成(cheng)機械(xie)能的一種設(she)備(bei)。它是(shi)利(li)用(yong)通電(dian)線圈(也就是(shi)定子繞組)產生旋轉(zhuan)磁場并作(zuo)用(yong)于轉(zhuan)子鼠(shu)籠式式閉合鋁框形成(cheng)磁電(dian)動力旋轉(zhuan)扭(niu)矩。
電(dian)(dian)(dian)動(dong)(dong)(dong)車(che)電(dian)(dian)(dian)機(ji)按使用(yong)電(dian)(dian)(dian)源不同(tong)分為直流(liu)(liu)電(dian)(dian)(dian)動(dong)(dong)(dong)機(ji)和交流(liu)(liu)電(dian)(dian)(dian)動(dong)(dong)(dong)機(ji),電(dian)(dian)(dian)力系統(tong)中的(de)電(dian)(dian)(dian)動(dong)(dong)(dong)機(ji)大部分是(shi)(shi)交流(liu)(liu)電(dian)(dian)(dian)機(ji),可以(yi)是(shi)(shi)同(tong)步(bu)電(dian)(dian)(dian)機(ji)或(huo)者(zhe)是(shi)(shi)異步(bu)電(dian)(dian)(dian)機(ji)(電(dian)(dian)(dian)機(ji)定子(zi)磁(ci)(ci)場轉(zhuan)(zhuan)速與(yu)轉(zhuan)(zhuan)子(zi)旋轉(zhuan)(zhuan)轉(zhuan)(zhuan)速不保(bao)持同(tong)步(bu)速)。電(dian)(dian)(dian)動(dong)(dong)(dong)機(ji)主要由定子(zi)與(yu)轉(zhuan)(zhuan)子(zi)組成,通電(dian)(dian)(dian)導線在磁(ci)(ci)場中受力運動(dong)(dong)(dong)的(de)方向(xiang)跟電(dian)(dian)(dian)流(liu)(liu)方向(xiang)和磁(ci)(ci)感(gan)線(磁(ci)(ci)場方向(xiang))方向(xiang)有(you)關(guan)。電(dian)(dian)(dian)動(dong)(dong)(dong)機(ji)工作(zuo)原理是(shi)(shi)磁(ci)(ci)場對電(dian)(dian)(dian)流(liu)(liu)受力的(de)作(zuo)用(yong),使電(dian)(dian)(dian)動(dong)(dong)(dong)機(ji)轉(zhuan)(zhuan)動(dong)(dong)(dong)。
二、電動車電機的組成結構
電動車電機普遍采用永磁直(zhi)流電(dian)機(ji)。電(dian)動車(che)電(dian)機(ji)按照電(dian)機(ji)的通電(dian)形(xing)式來(lai)(lai)分,可分為有刷(shua)電(dian)機(ji)和無刷(shua)電(dian)機(ji)兩(liang)(liang)大類;按照電(dian)機(ji)總(zong)成的機(ji)械結構來(lai)(lai)分,一般分為“有齒”(電(dian)機(ji)轉速(su)高,需要(yao)經(jing)過(guo)齒輪減(jian)速(su))和“無齒”(電(dian)機(ji)扭矩(ju)輸出不經(jing)過(guo)任何減(jian)速(su))兩(liang)(liang)大類。
1、永磁式直流電機
由定子磁極(ji)、轉子、電刷、外殼等組成。
定子磁極采用永(yong)磁體(ti)(永(yong)久磁鋼),有鐵氧(yang)體(ti)、鋁鎳鈷、釹鐵硼等(deng)材料。按其結(jie)構(gou)形式可(ke)分為圓(yuan)筒型和(he)瓦塊型等(deng)幾種。
轉(zhuan)子一般采用(yong)硅鋼片疊壓而成(cheng),漆包(bao)線繞在(zai)轉(zhuan)子鐵心的(de)兩槽之間(jian)(三槽即有三個繞組),其各接頭分(fen)別焊在(zai)換向(xiang)器的(de)金(jin)屬(shu)片上(shang)。
電(dian)(dian)刷(shua)是連接電(dian)(dian)源與(yu)轉子(zi)繞組的(de)(de)導電(dian)(dian)部件(jian),具備導電(dian)(dian)與(yu)耐(nai)磨兩(liang)種性(xing)能(neng)。永磁電(dian)(dian)機的(de)(de)電(dian)(dian)刷(shua)使用單性(xing)金(jin)屬片或金(jin)屬石墨電(dian)(dian)刷(shua)、電(dian)(dian)化石墨電(dian)(dian)刷(shua)。
2、無刷直流電機
由永磁體轉子(zi)、多極繞組(zu)定子(zi)、位置(zhi)傳感(gan)器(qi)等組(zu)成。無(wu)刷(shua)直流電(dian)(dian)機的(de)特點(dian)是無(wu)刷(shua),采用(yong)半導體開(kai)關(guan)器(qi)件(如霍(huo)爾元件)來實現電(dian)(dian)子(zi)換向(xiang)(xiang)的(de),即用(yong)電(dian)(dian)子(zi)開(kai)關(guan)器(qi)件代替傳統的(de)接觸式(shi)換向(xiang)(xiang)器(qi)和電(dian)(dian)刷(shua)。它具有可靠性高、無(wu)換向(xiang)(xiang)火花、機械噪聲低(di)等優點(dian)。如圖1所示。
位(wei)置傳(chuan)(chuan)感器按轉子位(wei)置的變(bian)化,沿著一定(ding)次序對(dui)定(ding)子繞(rao)組(zu)的電(dian)流(liu)進行換流(liu)(即檢測轉子磁極相(xiang)對(dui)定(ding)子繞(rao)組(zu)的位(wei)置,并在確定(ding)的位(wei)置處產生位(wei)置傳(chuan)(chuan)感信號,經信號轉換電(dian)路(lu)處理后去控制(zhi)功率開關電(dian)路(lu),按一定(ding)的邏(luo)輯關系進行繞(rao)組(zu)電(dian)流(liu)切換)。
3、高速永磁無刷電機
由(you)定子鐵心、磁鋼轉子、太陽輪、減(jian)速離(li)合器、輪轂(gu)外殼等組(zu)成。
電機蓋子上面可(ke)以裝上霍爾(er)傳感器,用以測速。
位置傳(chuan)感器有磁(ci)敏式(shi)、光電(dian)式(shi)和電(dian)磁(ci)式(shi)三種類型。
采(cai)用(yong)(yong)磁敏(min)式位置(zhi)傳感器的(de)無(wu)刷(shua)直流電(dian)動機,其磁敏(min)傳感器件(jian)(例如霍爾元件(jian)、磁敏(min)二極管、磁敏(min)詁極管、磁敏(min)電(dian)阻器或專用(yong)(yong)集成電(dian)路等)裝在定子組件(jian)上,用(yong)(yong)來檢測(ce)永磁體、轉子旋轉時產生的(de)磁場變化。電(dian)動汽車多用(yong)(yong)的(de)是霍爾元件(jian)。
采(cai)用光(guang)電式位置(zhi)傳感(gan)器的(de)無刷直流電動機,在定(ding)子組件(jian)上(shang)按(an)一定(ding)位置(zhi)配置(zhi)了(le)光(guang)電傳感(gan)器件(jian),轉(zhuan)子上(shang)裝(zhuang)有遮光(guang)板(ban),光(guang)源(yuan)為發(fa)光(guang)二極管或小燈泡(pao)。轉(zhuan)子旋(xuan)轉(zhuan)時,由(you)于遮光(guang)板(ban)的(de)作用,定(ding)子上(shang)的(de)光(guang)敏元器件(jian)將會按(an)一定(ding)頻(pin)率(lv)間歇間生脈(mo)沖(chong)信號。
采用電(dian)磁(ci)(ci)(ci)式位(wei)置傳(chuan)感(gan)器(qi)的無刷直流電(dian)動機,是(shi)在(zai)定子(zi)組(zu)件上安裝有電(dian)磁(ci)(ci)(ci)傳(chuan)感(gan)器(qi)部件(例如耦合變(bian)壓器(qi)、接近開關、LC諧振電(dian)路(lu)等),當永(yong)磁(ci)(ci)(ci)體(ti)轉(zhuan)子(zi)位(wei)置發生變(bian)化時,電(dian)磁(ci)(ci)(ci)效應將(jiang)使(shi)電(dian)磁(ci)(ci)(ci)傳(chuan)感(gan)器(qi)產(chan)生高頻調制信(xin)號(其(qi)幅值隨轉(zhuan)子(zi)位(wei)置而變(bian)化)。
定子繞組的(de)工作電壓由(you)位置傳感器輸(shu)出控制的(de)電子開關電路提供(gong)。