太陽能光伏發電原理
太陽能電池與蓄電池組成(cheng)系統(tong)的電源(yuan)單元,因此蓄電池(chi)性能(neng)直(zhi)接影響著系統(tong)工作特性。
(1)電(dian)(dian)(dian)(dian)(dian)池(chi)單(dan)(dan)元:由于(yu)技術和(he)(he)材料原(yuan)因,單(dan)(dan)一電(dian)(dian)(dian)(dian)(dian)池(chi)的(de)發電(dian)(dian)(dian)(dian)(dian)量是(shi)十(shi)分有(you)限的(de),實用中(zhong)的(de)太(tai)(tai)陽(yang)能電(dian)(dian)(dian)(dian)(dian)池(chi)是(shi)單(dan)(dan)一電(dian)(dian)(dian)(dian)(dian)池(chi)經串、并聯組(zu)成(cheng)的(de)電(dian)(dian)(dian)(dian)(dian)池(chi)系統,稱為電(dian)(dian)(dian)(dian)(dian)池(chi)組(zu)件(陣(zhen)列)。單(dan)(dan)一電(dian)(dian)(dian)(dian)(dian)池(chi)是(shi)一只(zhi)硅晶體(ti)二極(ji)管,根據半(ban)導(dao)體(ti)材料的(de)電(dian)(dian)(dian)(dian)(dian)子學特性,當太(tai)(tai)陽(yang)光(guang)照(zhao)射到(dao)由P型(xing)和(he)(he)N型(xing)兩種(zhong)不同導(dao)電(dian)(dian)(dian)(dian)(dian)類型(xing)的(de)同質半(ban)導(dao)體(ti)材料構成(cheng)的(de)P-N結上(shang)時,在一定(ding)的(de)條(tiao)件下,太(tai)(tai)陽(yang)能輻射被半(ban)導(dao)體(ti)材料吸收,在導(dao)帶(dai)(dai)和(he)(he)價帶(dai)(dai)中(zhong)產生非平衡載(zai)流子即(ji)電(dian)(dian)(dian)(dian)(dian)子和(he)(he)空(kong)穴。同于(yu)P-N結勢壘區存在著較強的(de)內建靜(jing)電(dian)(dian)(dian)(dian)(dian)場(chang),因而能在光(guang)照(zhao)下形成(cheng)電(dian)(dian)(dian)(dian)(dian)流密度J,短路(lu)(lu)電(dian)(dian)(dian)(dian)(dian)流Isc,開(kai)路(lu)(lu)電(dian)(dian)(dian)(dian)(dian)壓(ya)Uoc。若在內建電(dian)(dian)(dian)(dian)(dian)場(chang)的(de)兩側面引出電(dian)(dian)(dian)(dian)(dian)極(ji)并接上(shang)負載(zai),理論上(shang)講(jiang)由P-N結、連(lian)接電(dian)(dian)(dian)(dian)(dian)路(lu)(lu)和(he)(he)負載(zai)形成(cheng)的(de)回路(lu)(lu),于(yu)是(shi)就有(you)“光(guang)生電(dian)(dian)(dian)(dian)(dian)流”流過,太(tai)(tai)陽(yang)能電(dian)(dian)(dian)(dian)(dian)池(chi)組(zu)件就實現(xian)了對負載(zai)的(de)功率P輸出。
(2)電能儲存單元:太陽能電池產生的(de)直(zhi)流電先進入蓄電池(chi)儲存,蓄電池(chi)的(de)特性影響著系統的(de)工作效率和特性。蓄電池(chi)技術是十分成熟的(de),但其容量(liang)要受到末(mo)端需電量(liang),日(ri)照(zhao)時(shi)(shi)間(發電時(shi)(shi)間)的(de)影響。因此蓄電池(chi)瓦時(shi)(shi)容量(liang)和安時(shi)(shi)容量(liang)由預定(ding)的(de)連續無日(ri)照(zhao)時(shi)(shi)間決定(ding)。
設置原理
太(tai)陽能光伏發電系統的(de)設計需要考慮的(de)因素(su):
1、需要考慮(lv)太陽能(neng)光(guang)伏發(fa)電系統使用(yong)的地方以及(ji)該(gai)地日(ri)光(guang)輻射情況;
2、需要考(kao)慮太(tai)陽能(neng)光伏發電系統需要承載(zai)(zai)的負載(zai)(zai)功率;
3、系統(tong)所輸出電壓,以及考慮應該使用直(zhi)流(liu)電還是交流(liu)電;
4、系統每天需要工作(zuo)的(de)小時(shi)數(shu);
5、如(ru)遇到沒(mei)有日(ri)光照射的陰雨天(tian)氣,系統需連續供電多少天(tian);
6、考(kao)慮負載(zai)的情(qing)況,是純電阻性(xing)、電容性(xing)還是電感性(xing),啟動電流的大(da)小。
太陽能光伏發電系統組成
光伏系統是(shi)由太(tai)陽(yang)(yang)能電池方陣,蓄電池組,充放(fang)電控制器(qi),逆變(bian)器(qi),交流(liu)配電柜(ju)、自(zi)動太(tai)陽(yang)(yang)能跟蹤系統、自(zi)動太(tai)陽(yang)(yang)能組件除塵系統等設備組成。其(qi)各部分設備的作用是(shi):
1、太陽能電池
在(zai)有(you)光(guang)照(無論(lun)是太(tai)(tai)(tai)陽(yang)(yang)光(guang),還是其它(ta)發光(guang)體產(chan)(chan)生的(de)光(guang)照)情況下,電(dian)(dian)(dian)(dian)池吸收光(guang)能(neng)(neng)(neng),電(dian)(dian)(dian)(dian)池兩端出現異號電(dian)(dian)(dian)(dian)荷的(de)積(ji)累(lei),即產(chan)(chan)生“光(guang)生電(dian)(dian)(dian)(dian)壓”,這就(jiu)是“光(guang)生伏特效(xiao)應(ying)”。在(zai)光(guang)生伏特效(xiao)應(ying)的(de)作用下,太(tai)(tai)(tai)陽(yang)(yang)能(neng)(neng)(neng)電(dian)(dian)(dian)(dian)池的(de)兩端產(chan)(chan)生電(dian)(dian)(dian)(dian)動勢,將光(guang)能(neng)(neng)(neng)轉換(huan)成電(dian)(dian)(dian)(dian)能(neng)(neng)(neng),是能(neng)(neng)(neng)量轉換(huan)的(de)器件(jian)。太(tai)(tai)(tai)陽(yang)(yang)能(neng)(neng)(neng)電(dian)(dian)(dian)(dian)池一(yi)般為(wei)硅電(dian)(dian)(dian)(dian)池,分(fen)為(wei)單晶硅太(tai)(tai)(tai)陽(yang)(yang)能(neng)(neng)(neng)電(dian)(dian)(dian)(dian)池,多晶硅太(tai)(tai)(tai)陽(yang)(yang)能(neng)(neng)(neng)電(dian)(dian)(dian)(dian)池和(he)非晶硅太(tai)(tai)(tai)陽(yang)(yang)能(neng)(neng)(neng)電(dian)(dian)(dian)(dian)池三種(zhong)。
原材料特點:
電(dian)池(chi)片(pian):采用高效率(lv)(16.5%以上(shang))的單晶硅太(tai)陽能片(pian)封裝,保證太(tai)陽能電(dian)池(chi)板發電(dian)功(gong)率(lv)充足(zu)。
玻璃:采(cai)用低鐵鋼化絨(rong)面玻璃(又稱為白玻璃),厚(hou)度3.2mm,在太陽電池光(guang)(guang)譜響應的(de)(de)波長范(fan)圍內(320-1100nm)透光(guang)(guang)率達(da)91%以上,對(dui)于(yu)大于(yu)1200 nm的(de)(de)紅外光(guang)(guang)有較高的(de)(de)反(fan)射率。此(ci)玻璃同時能(neng)耐太陽紫外光(guang)(guang)線的(de)(de)輻射,透光(guang)(guang)率不下(xia)降。
EVA:采用加(jia)有抗(kang)(kang)紫(zi)外劑、抗(kang)(kang)氧化劑和固(gu)化劑的(de)(de)厚度為0.78mm的(de)(de)優質EVA膜層作為太(tai)陽電池的(de)(de)密封劑和與玻(bo)璃、TPT之(zhi)間的(de)(de)連接劑。具有較高的(de)(de)透光(guang)率和抗(kang)(kang)老化能力。
TPT:太陽電(dian)池(chi)的(de)背面覆(fu)蓋物—氟塑料(liao)膜為白色,對(dui)陽光起反射(she)(she)作用,因(yin)此對(dui)組件的(de)效率略有(you)提高,并(bing)因(yin)其(qi)具(ju)(ju)有(you)較高的(de)紅外發射(she)(she)率,還可降低組件的(de)工作溫度(du),也有(you)利于提高組件的(de)效率。當(dang)然,此氟塑料(liao)膜首先(xian)具(ju)(ju)有(you)太陽電(dian)池(chi)封裝材料(liao)所要(yao)求的(de)耐老化(hua)、耐腐蝕、不透氣等基(ji)本要(yao)求。
邊框(kuang):所采用的鋁合(he)金邊框(kuang)具有高(gao)強度,抗機械沖擊能(neng)力強。也(ye)是家用太(tai)陽(yang)能(neng)發電中價值最(zui)高(gao)的部(bu)分(fen)。
2、蓄電池組
其作用(yong)(yong)是(shi)(shi)貯存太陽(yang)能(neng)(neng)電(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)方陣受(shou)光照時發出(chu)的(de)(de)電(dian)(dian)(dian)(dian)能(neng)(neng)并可隨時向負載供電(dian)(dian)(dian)(dian)。太陽(yang)能(neng)(neng)電(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)發電(dian)(dian)(dian)(dian)對所用(yong)(yong)蓄(xu)(xu)(xu)電(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)組的(de)(de)基本(ben)要求(qiu)是(shi)(shi):a.自放(fang)電(dian)(dian)(dian)(dian)率(lv)低;b.使用(yong)(yong)壽命長;c.深放(fang)電(dian)(dian)(dian)(dian)能(neng)(neng)力強;d.充(chong)電(dian)(dian)(dian)(dian)效率(lv)高;e.少維護或免(mian)維護;f.工作溫度范圍寬;g.價格低廉。目前我國與太陽(yang)能(neng)(neng)發電(dian)(dian)(dian)(dian)系統配(pei)(pei)套(tao)使用(yong)(yong)的(de)(de)蓄(xu)(xu)(xu)電(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)主(zhu)要是(shi)(shi)鉛(qian)(qian)酸蓄(xu)(xu)(xu)電(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)和鎘鎳蓄(xu)(xu)(xu)電(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)。配(pei)(pei)套(tao)200Ah以(yi)上的(de)(de)鉛(qian)(qian)酸蓄(xu)(xu)(xu)電(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi),一般選(xuan)用(yong)(yong)固定(ding)式或工業密封式免(mian)維護鉛(qian)(qian)酸蓄(xu)(xu)(xu)電(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi),每只蓄(xu)(xu)(xu)電(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)的(de)(de)額定(ding)電(dian)(dian)(dian)(dian)壓(ya)為2VDC;配(pei)(pei)套(tao)200Ah以(yi)下的(de)(de)鉛(qian)(qian)酸蓄(xu)(xu)(xu)電(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi),一般選(xuan)用(yong)(yong)小型密封免(mian)維護鉛(qian)(qian)酸蓄(xu)(xu)(xu)電(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi),每只蓄(xu)(xu)(xu)電(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)的(de)(de)額定(ding)電(dian)(dian)(dian)(dian)壓(ya)為12VDC。
3、充放電控制器
是能(neng)自動防止(zhi)蓄(xu)電(dian)(dian)池(chi)(chi)過(guo)充(chong)電(dian)(dian)和(he)過(guo)放電(dian)(dian)的(de)(de)(de)設備。由于(yu)蓄(xu)電(dian)(dian)池(chi)(chi)的(de)(de)(de)循環充(chong)放電(dian)(dian)次數及放電(dian)(dian)深(shen)度是決(jue)定蓄(xu)電(dian)(dian)池(chi)(chi)使(shi)用壽命的(de)(de)(de)重要因(yin)素,因(yin)此能(neng)控制蓄(xu)電(dian)(dian)池(chi)(chi)組過(guo)充(chong)電(dian)(dian)或過(guo)放電(dian)(dian)的(de)(de)(de)充(chong)放電(dian)(dian)控制器是必不(bu)可少的(de)(de)(de)設備。
4、逆變器
是(shi)將(jiang)直流(liu)電(dian)(dian)(dian)轉換(huan)成交流(liu)電(dian)(dian)(dian)的(de)設備(bei)。由于太陽(yang)能(neng)電(dian)(dian)(dian)池和蓄電(dian)(dian)(dian)池是(shi)直流(liu)電(dian)(dian)(dian)源,而負載是(shi)交流(liu)負載時,逆(ni)變(bian)(bian)器是(shi)必不(bu)可(ke)少的(de)。逆(ni)變(bian)(bian)器按(an)運(yun)行(xing)(xing)方(fang)式,可(ke)分為(wei)獨(du)立運(yun)行(xing)(xing)逆(ni)變(bian)(bian)器和并網(wang)逆(ni)變(bian)(bian)器。獨(du)立運(yun)行(xing)(xing)逆(ni)變(bian)(bian)器用(yong)(yong)于獨(du)立運(yun)行(xing)(xing)的(de)太陽(yang)能(neng)電(dian)(dian)(dian)池發電(dian)(dian)(dian)系(xi)(xi)統,為(wei)獨(du)立負載供電(dian)(dian)(dian)。并網(wang)逆(ni)變(bian)(bian)器用(yong)(yong)于并網(wang)運(yun)行(xing)(xing)的(de)太陽(yang)能(neng)電(dian)(dian)(dian)池發電(dian)(dian)(dian)系(xi)(xi)統。逆(ni)變(bian)(bian)器按(an)輸出波(bo)型可(ke)分為(wei)方(fang)波(bo)逆(ni)變(bian)(bian)器和正弦波(bo)逆(ni)變(bian)(bian)器。方(fang)波(bo)逆(ni)變(bian)(bian)器電(dian)(dian)(dian)路簡(jian)單,造價低(di),但諧(xie)波(bo)分量大,一般用(yong)(yong)于幾(ji)百瓦(wa)以(yi)下和對諧(xie)波(bo)要(yao)求不(bu)高的(de)系(xi)(xi)統。正弦波(bo)逆(ni)變(bian)(bian)器成本高,但可(ke)以(yi)適(shi)用(yong)(yong)于各(ge)種負載。
逆變器保護功能:a、過載保護;b、短路保護;c、接(jie)反(fan)保護;d、欠(qian)壓保護;e、過壓保護;f、過熱保護。
5、交流配電柜
其在電(dian)站系(xi)統(tong)的(de)主要作用(yong)是對(dui)(dui)備用(yong)逆變器的(de)切換功能,保證(zheng)系(xi)統(tong)的(de)正常供電(dian),同時還有對(dui)(dui)線路電(dian)能的(de)計量。
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