矢量變頻器工作原理
矢量(liang)(liang)變(bian)頻器的(de)原理是矢量(liang)(liang)控(kong)制技術通過(guo)坐標(biao)變(bian)換,將三相系統等效(xiao)變(bian)換為M-T兩(liang)相系統,將交流電(dian)機(ji)定子(zi)電(dian)流矢量(liang)(liang)分解成兩(liang)個直(zhi)流分量(liang)(liang),從(cong)而達(da)到分別控(kong)制交流電(dian)動機(ji)的(de)磁通和轉矩的(de)目的(de),因而可獲(huo)得(de)與直(zhi)流調速(su)系統同樣(yang)好的(de)控(kong)制效(xiao)果。
通過(guo)矢量運算器產(chan)生磁場定(ding)向定(ding)子電(dian)流分量,給定(ding)值和滑差(cha)角頻度給定(ding)值和測量所得(de)的電(dian)機轉速,經(jing)過(guo)積分運算可得(de)轉子磁通位置角θ,并送(song)至(zhi)旋轉變換環(huan)節。
矢量(liang)變(bian)頻(pin)(pin)器(qi)(qi)的(de)系(xi)(xi)統(tong)(tong)(tong)組(zu)成:基(ji)于雙DSP矢量(liang)控(kong)(kong)制(zhi)(zhi)的(de)三(san)(san)相籠型(xing)異步電(dian)(dian)(dian)機(ji)驅動(dong)系(xi)(xi)統(tong)(tong)(tong)的(de)變(bian)頻(pin)(pin)器(qi)(qi)采用交(jiao)(jiao)(jiao)直交(jiao)(jiao)(jiao)電(dian)(dian)(dian)壓(ya)型(xing)結構(gou)和SVPWM脈寬調制(zhi)(zhi)方式。矢量(liang)變(bian)頻(pin)(pin)器(qi)(qi)系(xi)(xi)統(tong)(tong)(tong)由三(san)(san)相整(zheng)流器(qi)(qi)、濾波電(dian)(dian)(dian)容、電(dian)(dian)(dian)壓(ya)型(xing)逆變(bian)器(qi)(qi)、逆變(bian)器(qi)(qi)驅動(dong)電(dian)(dian)(dian)路(lu)、三(san)(san)相籠型(xing)異步電(dian)(dian)(dian)機(ji)和雙DSP控(kong)(kong)制(zhi)(zhi)系(xi)(xi)統(tong)(tong)(tong)構(gou)成。其中雙DSP控(kong)(kong)制(zhi)(zhi)系(xi)(xi)統(tong)(tong)(tong)由VC33子系(xi)(xi)統(tong)(tong)(tong),F240子系(xi)(xi)統(tong)(tong)(tong)和數據(ju)交(jiao)(jiao)(jiao)換單元(yuan)三(san)(san)部(bu)分構(gou)成。矢量(liang)控(kong)(kong)制(zhi)(zhi)以VC33芯片為核(he)心,用來完(wan)成矢量(liang)控(kong)(kong)制(zhi)(zhi)核(he)心算(suan)法,及(ji)兩相電(dian)(dian)(dian)流檢測。
矢量變頻器和普通變頻器的區別
變頻(pin)(pin)(pin)器(qi)有通(tong)用型(xing)變頻(pin)(pin)(pin)器(qi)和矢量型(xing)變頻(pin)(pin)(pin)器(qi)兩(liang)種,不(bu)過這兩(liang)種變頻(pin)(pin)(pin)器(qi)雖然都可以使用,但是(shi)這兩(liang)種變頻(pin)(pin)(pin)器(qi)還是(shi)有區別的,看了下面的分析就明白矢量變頻(pin)(pin)(pin)器(qi)為什么價格比通(tong)用變頻(pin)(pin)(pin)器(qi)價格高了。
矢量變頻器跟普通變頻主要有兩種區別:一是(shi)(shi)控制精(jing)度高,二就是(shi)(shi)低轉(zhuan)速輸(shu)出(chu)轉(zhuan)矩(ju)(ju)大(da)。可以輸(shu)出(chu)額定轉(zhuan)矩(ju)(ju)150%-200%的轉(zhuan)矩(ju)(ju)。因為矢(shi)量變(bian)頻是(shi)(shi)把電(dian)(dian)機(ji)電(dian)(dian)流(liu)(liu)(liu)分(fen)(fen)解為D軸(zhou)電(dian)(dian)流(liu)(liu)(liu)和(he)Q軸(zhou)電(dian)(dian)流(liu)(liu)(liu),其中D軸(zhou)電(dian)(dian)流(liu)(liu)(liu)是(shi)(shi)勵(li)磁(ci)電(dian)(dian)流(liu)(liu)(liu),Q軸(zhou)電(dian)(dian)流(liu)(liu)(liu)是(shi)(shi)力矩(ju)(ju)電(dian)(dian)流(liu)(liu)(liu)。通(tong)過(guo)把D和(he)Q分(fen)(fen)開(kai)控制,可使電(dian)(dian)動機(ji)得到更大(da)的啟動轉(zhuan)矩(ju)(ju)。一般應(ying)用在(zai)重(zhong)負載啟動的場合。例如大(da)功率(lv)的長皮(pi)帶,和(he)提升機(ji)等等。而此(ci)時選用普通(tong)變(bian)頻器(qi)由(you)于在(zai)啟動時負載太(tai)重(zhong),輸(shu)出(chu)轉(zhuan)矩(ju)(ju)不夠,會(hui)使電(dian)(dian)機(ji)啟動不了,而報電(dian)(dian)機(ji)堵轉(zhuan)或者變(bian)頻器(qi)過(guo)電(dian)(dian)流(liu)(liu)(liu)等故障(zhang)。
對于(yu)普通(tong)水泵的控(kong)制選(xuan)用風(feng)機水泵專用型或(huo)者通(tong)用型的就可以(yi),沒必要(yao)選(xuan)矢量(liang),價格高。關于(yu)參數設置都大同小異(yi)。沒什么主要(yao)的區別。
用(yong)開(kai)車(che)來打比方,大家知道:矢(shi)量(liang)控(kong)制(zhi)又稱為‘速度控(kong)制(zhi)’,從字面上就可以(yi)看出幾分區別。
V/F控(kong)制(zhi)(zhi)方式:就(jiu)像(xiang)開車時你腳上(shang)的(de)油門開度是(shi)保(bao)持不變(bian)的(de),而這(zhe)時車子(zi)的(de)速(su)度肯定是(shi)在變(bian)化(hua)的(de)!因為車子(zi)行走(zou)的(de)道路(lu)是(shi)不平的(de),道路(lu)的(de)阻力也是(shi)在變(bian)化(hua)的(de),上(shang)坡時速(su)度就(jiu)會慢(man)下(xia)來(lai),下(xia)坡時速(su)度就(jiu)會加快(kuai)。對變(bian)頻(pin)器(qi)來(lai)說,這(zhe)時你的(de)頻(pin)率設定值就(jiu)是(shi)相當于(yu)你開車時腳上(shang)油門的(de)開度,V/F控(kong)制(zhi)(zhi)時油門開度是(shi)固定的(de)。
矢量控(kong)制方式:可以(yi)控(kong)制車子在(zai)路況變(bian)(bian)化(hua)、阻(zu)力變(bian)(bian)化(hua)、上坡(po)、下(xia)坡(po)等變(bian)(bian)化(hua)情況下(xia),盡(jin)量讓(rang)車速(su)(su)保(bao)持恒定(ding)不變(bian)(bian),提高速(su)(su)度(du)控(kong)制精度(du)。那(nei)么(me),要(yao)想在(zai)無論上坡(po)、下(xia)坡(po)、路況阻(zu)力變(bian)(bian)化(hua)的情況下(xia),都讓(rang)車速(su)(su)穩定(ding)不變(bian)(bian),油門開度(du)肯(ken)定(ding)要(yao)隨時調節(jie)。
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