矢量變頻器工作原理
矢(shi)量(liang)變頻器的(de)原(yuan)理是(shi)矢(shi)量(liang)控(kong)制(zhi)技術通過坐標(biao)變換(huan)(huan),將三(san)相(xiang)系(xi)(xi)統(tong)等效(xiao)變換(huan)(huan)為M-T兩相(xiang)系(xi)(xi)統(tong),將交流(liu)電(dian)機(ji)定(ding)子電(dian)流(liu)矢(shi)量(liang)分解成兩個直流(liu)分量(liang),從而(er)達到分別(bie)控(kong)制(zhi)交流(liu)電(dian)動機(ji)的(de)磁(ci)通和轉矩(ju)的(de)目的(de),因而(er)可獲得與直流(liu)調速系(xi)(xi)統(tong)同樣好的(de)控(kong)制(zhi)效(xiao)果。
通過矢量(liang)運(yun)算器(qi)產(chan)生磁(ci)場定向定子電流分量(liang),給定值和滑(hua)差角(jiao)頻度給定值和測量(liang)所(suo)得(de)的電機轉速,經過積分運(yun)算可得(de)轉子磁(ci)通位置角(jiao)θ,并送至旋轉變換環節。
矢(shi)量(liang)變(bian)頻(pin)器(qi)的(de)系(xi)(xi)(xi)統組成(cheng):基于雙(shuang)(shuang)DSP矢(shi)量(liang)控(kong)(kong)制(zhi)(zhi)的(de)三相籠型(xing)異步電機驅(qu)動(dong)系(xi)(xi)(xi)統的(de)變(bian)頻(pin)器(qi)采用(yong)交直(zhi)交電壓型(xing)結構和SVPWM脈寬調制(zhi)(zhi)方式。矢(shi)量(liang)變(bian)頻(pin)器(qi)系(xi)(xi)(xi)統由三相整流(liu)(liu)器(qi)、濾波(bo)電容、電壓型(xing)逆(ni)變(bian)器(qi)、逆(ni)變(bian)器(qi)驅(qu)動(dong)電路、三相籠型(xing)異步電機和雙(shuang)(shuang)DSP控(kong)(kong)制(zhi)(zhi)系(xi)(xi)(xi)統構成(cheng)。其(qi)中雙(shuang)(shuang)DSP控(kong)(kong)制(zhi)(zhi)系(xi)(xi)(xi)統由VC33子(zi)系(xi)(xi)(xi)統,F240子(zi)系(xi)(xi)(xi)統和數據交換單(dan)元三部分構成(cheng)。矢(shi)量(liang)控(kong)(kong)制(zhi)(zhi)以(yi)VC33芯片為核心(xin),用(yong)來完成(cheng)矢(shi)量(liang)控(kong)(kong)制(zhi)(zhi)核心(xin)算法,及兩相電流(liu)(liu)檢測。
矢量變頻器和普通變頻器的區別
變(bian)(bian)頻(pin)(pin)器有(you)通用(yong)(yong)型變(bian)(bian)頻(pin)(pin)器和矢量型變(bian)(bian)頻(pin)(pin)器兩種,不(bu)過這(zhe)兩種變(bian)(bian)頻(pin)(pin)器雖(sui)然都(dou)可以使用(yong)(yong),但是(shi)這(zhe)兩種變(bian)(bian)頻(pin)(pin)器還是(shi)有(you)區別的,看(kan)了下面的分析(xi)就明(ming)白矢量變(bian)(bian)頻(pin)(pin)器為什么(me)價格(ge)比通用(yong)(yong)變(bian)(bian)頻(pin)(pin)器價格(ge)高了。
矢量變頻器跟普通變頻主要有兩種區別:一是控(kong)制精度高,二就是低轉(zhuan)速輸出(chu)轉(zhuan)矩(ju)(ju)大。可以(yi)輸出(chu)額定轉(zhuan)矩(ju)(ju)150%-200%的(de)(de)轉(zhuan)矩(ju)(ju)。因為(wei)矢量變頻是把電(dian)(dian)(dian)(dian)(dian)機(ji)電(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)分解為(wei)D軸電(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)和(he)Q軸電(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu),其中D軸電(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)是勵磁(ci)電(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu),Q軸電(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)是力(li)矩(ju)(ju)電(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)。通(tong)過(guo)把D和(he)Q分開控(kong)制,可使電(dian)(dian)(dian)(dian)(dian)動(dong)(dong)機(ji)得到更大的(de)(de)啟(qi)動(dong)(dong)轉(zhuan)矩(ju)(ju)。一般(ban)應用在(zai)(zai)重(zhong)負載啟(qi)動(dong)(dong)的(de)(de)場合。例如大功率的(de)(de)長皮帶,和(he)提升機(ji)等等。而(er)此時(shi)選用普通(tong)變頻器由于(yu)在(zai)(zai)啟(qi)動(dong)(dong)時(shi)負載太(tai)重(zhong),輸出(chu)轉(zhuan)矩(ju)(ju)不(bu)夠,會(hui)使電(dian)(dian)(dian)(dian)(dian)機(ji)啟(qi)動(dong)(dong)不(bu)了,而(er)報電(dian)(dian)(dian)(dian)(dian)機(ji)堵轉(zhuan)或者變頻器過(guo)電(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)等故障。
對于(yu)普通(tong)水泵(beng)的(de)控制選用風機水泵(beng)專(zhuan)用型或者通(tong)用型的(de)就可以,沒必要(yao)選矢(shi)量,價格高。關于(yu)參數(shu)設置都大同小異。沒什(shen)么主要(yao)的(de)區別(bie)。
用(yong)開車來打(da)比(bi)方,大家知道:矢(shi)量控制又稱為(wei)‘速度控制’,從字(zi)面上就(jiu)可以看出幾分(fen)區別。
V/F控制方式:就(jiu)(jiu)像開(kai)車時(shi)你腳上的(de)油門(men)(men)開(kai)度(du)(du)是保持(chi)不變(bian)(bian)(bian)的(de),而這時(shi)車子的(de)速度(du)(du)肯(ken)定(ding)(ding)是在(zai)變(bian)(bian)(bian)化的(de)!因為車子行走的(de)道路是不平的(de),道路的(de)阻力也是在(zai)變(bian)(bian)(bian)化的(de),上坡時(shi)速度(du)(du)就(jiu)(jiu)會慢(man)下來,下坡時(shi)速度(du)(du)就(jiu)(jiu)會加(jia)快。對變(bian)(bian)(bian)頻器來說,這時(shi)你的(de)頻率(lv)設定(ding)(ding)值就(jiu)(jiu)是相當(dang)于你開(kai)車時(shi)腳上油門(men)(men)的(de)開(kai)度(du)(du),V/F控制時(shi)油門(men)(men)開(kai)度(du)(du)是固定(ding)(ding)的(de)。
矢量(liang)控(kong)制(zhi)方(fang)式:可以控(kong)制(zhi)車子在(zai)路況變(bian)(bian)化、阻力變(bian)(bian)化、上坡、下(xia)(xia)坡等變(bian)(bian)化情(qing)(qing)況下(xia)(xia),盡量(liang)讓(rang)車速(su)(su)保持恒定(ding)不變(bian)(bian),提高速(su)(su)度(du)控(kong)制(zhi)精度(du)。那(nei)么(me),要(yao)想在(zai)無(wu)論上坡、下(xia)(xia)坡、路況阻力變(bian)(bian)化的情(qing)(qing)況下(xia)(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。
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