光伏逆變器的功能
光伏逆變器是一種電源調整器,可分為獨立型電源用和并網用兩種類型。光伏逆變器品牌產品能(neng)將直(zhi)(zhi)(zhi)流(liu)(liu)(liu)電(dian)(dian)(dian)轉(zhuan)化為(wei)交(jiao)流(liu)(liu)(liu)電(dian)(dian)(dian)的(de)(de)裝(zhuang)置,若直(zhi)(zhi)(zhi)流(liu)(liu)(liu)電(dian)(dian)(dian)壓較低,則通過(guo)交(jiao)流(liu)(liu)(liu)變(bian)壓器升壓,即(ji)(ji)得到標準交(jiao)流(liu)(liu)(liu)電(dian)(dian)(dian)壓和頻(pin)率。大容(rong)量逆變(bian)器的(de)(de)直(zhi)(zhi)(zhi)流(liu)(liu)(liu)母線電(dian)(dian)(dian)壓較高,交(jiao)流(liu)(liu)(liu)輸出(chu)一般不需要(yao)變(bian)壓器升壓即(ji)(ji)能(neng)達到220V,在中(zhong)、小容(rong)量的(de)(de)逆變(bian)器中(zhong),由于(yu)直(zhi)(zhi)(zhi)流(liu)(liu)(liu)電(dian)(dian)(dian)壓較低,就必(bi)須設計升壓電(dian)(dian)(dian)路。
光伏逆變器的工作原理
大容量光伏逆變器是由升(sheng)(sheng)壓(ya)(ya)(ya)回路(lu)和逆變橋(qiao)式回路(lu)構成的(de),其工作原理很簡單。升(sheng)(sheng)壓(ya)(ya)(ya)回路(lu)把太陽電池的(de)直(zhi)流電壓(ya)(ya)(ya)升(sheng)(sheng)壓(ya)(ya)(ya)到逆變器輸出(chu)控制所需(xu)的(de)直(zhi)流電壓(ya)(ya)(ya),逆變橋(qiao)式回路(lu)則把升(sheng)(sheng)壓(ya)(ya)(ya)后的(de)直(zhi)流電壓(ya)(ya)(ya)等價地轉換成常用頻(pin)率(lv)的(de)交流電壓(ya)(ya)(ya),這就(jiu)是它的(de)原理。
中、小容(rong)量(liang)逆變器一(yi)般有(you)(you)推挽(wan)逆變電(dian)(dian)(dian)(dian)路(lu)、全(quan)橋(qiao)逆變電(dian)(dian)(dian)(dian)路(lu)這兩(liang)種逆變橋(qiao)式回路(lu)。推挽(wan)電(dian)(dian)(dian)(dian)路(lu)能將升壓變壓器的中性插頭接(jie)于正電(dian)(dian)(dian)(dian)源,兩(liang)只(zhi)功率管(guan)交替工作(zuo),輸出(chu)得(de)到交流(liu)電(dian)(dian)(dian)(dian)力(li),由于功率晶體管(guan)共地邊(bian)接(jie),驅(qu)動及控制(zhi)電(dian)(dian)(dian)(dian)路(lu)簡單,且變壓器具(ju)有(you)(you)一(yi)定的漏感,因此(ci)它(ta)可(ke)以限制(zhi)短路(lu)電(dian)(dian)(dian)(dian)流(liu),因而提高了電(dian)(dian)(dian)(dian)路(lu)的可(ke)靠性。全(quan)橋(qiao)逆變電(dian)(dian)(dian)(dian)路(lu)具(ju)有(you)(you)續流(liu)回路(lu),即使有(you)(you)感性負載,輸出(chu)電(dian)(dian)(dian)(dian)壓波形也不會(hui)畸變,但它(ta)必(bi)須采用專(zhuan)門(men)驅(qu)動電(dian)(dian)(dian)(dian)路(lu)才能正常使用。為(wei)防止上(shang)、下(xia)橋(qiao)臂發生(sheng)共同(tong)導通(tong),全(quan)橋(qiao)逆變電(dian)(dian)(dian)(dian)路(lu)必(bi)須設置死區時(shi)間(jian),才不會(hui)出(chu)錯,因此(ci)它(ta)的電(dian)(dian)(dian)(dian)路(lu)結構較(jiao)復雜。
光伏逆變器怎么選
1、光伏(fu)逆變器的(de)大小應(ying)根(gen)據土地或者(zhe)屋頂使用面(mian)積(ji)來計算(suan),計算(suan)時要考慮到傾斜(xie)角度、支架安裝方式等,以(yi)盡量不出現(xian)陰影遮擋為原(yuan)則。
2、光伏(fu)逆(ni)(ni)變器MPPT的路(lu)(lu)數在很大程度(du)上決定著一(yi)個光伏(fu)電站的發電量(liang),而逆(ni)(ni)變器輸(shu)入路(lu)(lu)數往往決定了一(yi)個光伏(fu)電站是否更加容易(yi)進行配板設(she)計(ji),因(yin)此(ci)購買前,一(yi)定要想好(hao)MPPT的路(lu)(lu)數要多少(shao)。
3、光伏(fu)逆(ni)變器(qi)的散(san)熱方式(shi)有強(qiang)制風冷(leng)、自(zi)然冷(leng)卻、水(shui)冷(leng)三種(zhong),其(qi)中(zhong)水(shui)冷(leng)方式(shi)主要應用于大(da)型集中(zhong)式(shi)逆(ni)變器(qi)且(qie)應用較少。從(cong)逆(ni)變器(qi)角度來看(kan),家庭用單相(xiang)逆(ni)變器(qi)功率等級較低,散(san)熱較少,選(xuan)擇強(qiang)制風冷(leng)即(ji)可。