我們渴望舒服一點的條件是，一個基于水霧系統而讓人涼快的解決方案，以克服困擾這片沙漠的干熱空氣。這可以用一臺由電壓源供電、連著一個帶噴嘴的噴霧水龍帶的水泵實現。噴霧系統的成功要素是電源，這個電源也可以用來給 LED 燈供電，以供夜間照明，或者給其它需要電源的外部設備充電。我們的計劃是，用太陽能電池板給一個海上用的深周期電池充電，然后用這塊電池給其它所有東西供電。隨即，我開始了太陽能電池板電池充電器的設計。

　　我(wo)(wo)有 3 周時間完成設計。我(wo)(wo)向朋友 Simon 請求幫助，Simon 以前(qian)用(yong)凌力爾特公司的(de) IC 搞(gao)過(guo)太(tai)陽(yang)能供電(dian)設計。除了(le)一(yi)臺顯示工作原(yuan)理的(de)樣(yang)機(ji)，Simon 還給了(le)我(wo)(wo)一(yi)份原(yuan)理圖，這(zhe)臺樣(yang)機(ji)從未連上太(tai)陽(yang)能電(dian)池板測試(shi)過(guo)，但(dan)在實(shi)(shi)驗室做過(guo)仿真(zhen)。我(wo)(wo)很興奮，有興趣用(yong)真(zhen)實(shi)(shi)的(de)太(tai)陽(yang)能電(dian)池板測試(shi)這(zhe)個設計，我(wo)(wo)們準備對樣(yang)機(ji)進行像樣(yang)的(de)測試(shi)。

　　一位朋友借(jie)給我(wo)兩塊(kuai) BP 太陽能(neng)電(dian)(dian)池(chi)板 （BP380U）。在(zai)大約 20V 最(zui)高輸出(chu)電(dian)(dian)壓和(he) 4A 最(zui)大輸出(chu)電(dian)(dian)流時(shi)(shi)，每(mei)塊(kuai)電(dian)(dian)池(chi)板的(de)峰值功率都是 80W （實際(ji)規格為，在(zai) 80W 最(zui)大功率時(shi)(shi)，電(dian)(dian)壓為 17.6V，電(dian)(dian)流為 4.55A）。把(ba)這(zhe)兩塊(kuai)太陽能(neng)電(dian)(dian)池(chi)板合起來，我(wo)希望在(zai)太陽光直接(jie)(jie)直射在(zai)電(dian)(dian)池(chi)板上時(shi)(shi)，在(zai)峰值條(tiao)件下能(neng)有 8A 的(de)總電(dian)(dian)流。太陽能(neng)電(dian)(dian)池(chi)板連接(jie)(jie)到 Simon 的(de)樣機上沒(mei)有幾(ji)(ji)分鐘，系統(tong)就充分運(yun)轉了 （圖 1 和(he)圖 2）。通過對樣機的(de)初步(bu)測試，查明了幾(ji)(ji)個故障，后(hou)來這(zhe)給我(wo)們節省了大量時(shi)(shi)間。

　　圖 1：測試 BP 太陽能電池板， BP380U （0 至 20V 輸出，4A 峰值(zhi)功率 80W）

　　圖 2：最初的太陽(yang)能充(chong)電電路樣(yang)機(ji)，采(cai)用 12V 海(hai)上用深周期電池 。

　　樣(yang)機運行良(liang)好(hao)，因此我(wo)(wo)購買了(le)幾(ji)塊凌力爾(er)特公司(si)的(de)(de)演示板，并稍(shao)作修改(gai)(gai)以(yi)使其更適合重新設計過(guo)(guo)的(de)(de)系(xi)(xi)統規格要求。我(wo)(wo)保(bao)持樣(yang)機作為備份和參考，同(tong)時我(wo)(wo)設計了(le)一個新系(xi)(xi)統。我(wo)(wo)們解決了(le)一些(xie)故(gu)障后，通過(guo)(guo)這些(xie)修改(gai)(gai)改(gai)(gai)善了(le)原來的(de)(de)樣(yang)機。總之，架構設計仍然是相同(tong)的(de)(de)：用 0 至 20V 的(de)(de)太陽能(neng)電池(chi)板，以(yi) 4A 的(de)(de)恒定電流給(gei)一個 12V 的(de)(de)電池(chi)充電,

   太(tai)陽(yang)能電(dian)(dian)池充電(dian)(dian)器系統設計

　　用這些演示板忙活幾天之后，我成功地完成了一個產生預期效果的設計，這設計將適合我們這次旅程。系統的方框圖如圖 3 所示，該圖顯示了一些 IC 和演示板功能。系統的照片如圖 4 所示，顯示了完整的太陽能電池板電池充電器單元。

　　圖(tu) 3：系統(tong)設計(ji)方框圖(tu)

　　圖 4：最終的太陽能充電器電路

　　視(shi)太陽的(de)(de)(de)位置不同(tong)而(er)不同(tong)，太陽能電(dian)池板最(zui)初(chu)的(de)(de)(de)輸(shu)出電(dian)壓在(zai) 0V 到 20V 之間(jian)變化，那么(me)(me)就用一個能接受這(zhe)么(me)(me)寬(kuan)輸(shu)出范圍的(de)(de)(de)穩壓器，并保(bao)持吸取低的(de)(de)(de)電(dian)流 （每(mei)個電(dian)池板上的(de)(de)(de)輸(shu)入電(dian)流最(zui)大值都是 4A），同(tong)時調節一個固定的(de)(de)(de)輸(shu)出電(dian)壓。這(zhe)是在(zai) DC1198A-B 演示(shi)板上用凌力爾(er)特公(gong)司的(de)(de)(de)微(wei)型模(mo)塊 （μModule） DC/DC 降壓-升壓型開關穩壓器 LTM4607 實現的(de)(de)(de)。

　　LTM4607 是(shi)一(yi)個(ge)小型(xing)(xing) LGA 封裝(zhuang) （15mm x 15mm x 2.8mm） 的(de)(de)(de)(de)(de)芯片，其中包括一(yi)個(ge)復(fu)(fu)雜(za)(za)的(de)(de)(de)(de)(de)降壓(ya)(ya)-升(sheng)壓(ya)(ya)型(xing)(xing) DC/DC 開(kai)關穩(wen)壓(ya)(ya)器(qi)(qi)(qi)所需的(de)(de)(de)(de)(de)所有(you)支持控制(zhi)組件(jian)。復(fu)(fu)雜(za)(za)的(de)(de)(de)(de)(de)開(kai)關控制(zhi)電(dian)(dian)(dian)路和(he) FET 內置(zhi)到(dao)(dao)微(wei)型(xing)(xing)模塊(kuai)穩(wen)壓(ya)(ya)器(qi)(qi)(qi)中，從而使(shi)(shi)該器(qi)(qi)(qi)件(jian)非常容易使(shi)(shi)用(yong)。結果是(shi)僅需一(yi)個(ge)微(wei)型(xing)(xing)模塊(kuai)穩(wen)壓(ya)(ya)器(qi)(qi)(qi)、電(dian)(dian)(dian)感器(qi)(qi)(qi)以及(ji)幾(ji)個(ge)電(dian)(dian)(dian)容器(qi)(qi)(qi)和(he)電(dian)(dian)(dian)阻器(qi)(qi)(qi)就(jiu)完成簡潔規則的(de)(de)(de)(de)(de)布局。4.5V 至 36V 的(de)(de)(de)(de)(de)寬輸(shu)入(ru)電(dian)(dian)(dian)壓(ya)(ya)范(fan)圍至固定 20V 輸(shu)出(chu)(chu) （范(fan)圍為 0.8V 至 24V） 對于太陽能電(dian)(dian)(dian)池(chi)(chi)(chi)板的(de)(de)(de)(de)(de)特(te)性 （0 至 20V 輸(shu)出(chu)(chu)） 正合適，而且該器(qi)(qi)(qi)件(jian)能加載(zai)高達(da) 5A 的(de)(de)(de)(de)(de)升(sheng)壓(ya)(ya)模式和(he) 10A 的(de)(de)(de)(de)(de)降壓(ya)(ya)模式。在太陽能電(dian)(dian)(dian)池(chi)(chi)(chi)板峰值功率(lv)時，20V 輸(shu)入(ru)至 20V/2.5A 輸(shu)出(chu)(chu)的(de)(de)(de)(de)(de)效(xiao)率(lv)是(shi) 91%，而且積極利(li)用(yong)了(le)降壓(ya)(ya)-升(sheng)壓(ya)(ya)型(xing)(xing)寬范(fan)圍輸(shu)入(ru)的(de)(de)(de)(de)(de)好處(chu)。就(jiu)這個(ge)系(xi)統設計(ji)的(de)(de)(de)(de)(de)目的(de)(de)(de)(de)(de)而言，輸(shu)出(chu)(chu)調節(jie)到(dao)(dao) 20V，用(yong)這個(ge)輸(shu)出(chu)(chu)給(gei) LTC1435/LT1620 高效(xiao)率(lv)、低壓(ya)(ya)差(cha)電(dian)(dian)(dian)池(chi)(chi)(chi)充電(dian)(dian)(dian)器(qi)(qi)(qi)系(xi)統供(gong)電(dian)(dian)(dian)。

　　在(zai)(zai) 14V 穩(wen)定(ding)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)時，LTC1435/LT1620 演示(shi)板(ban) （DC133A） 將(jiang)(jiang)(jiang)充(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)控(kong)制到(dao)穩(wen)定(ding)的(de)(de)(de) 4A.該(gai)演示(shi)板(ban)與(yu) LT1620 數據(ju)表(biao)第一頁上的(de)(de)(de)應(ying)用(yong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)類似，我將(jiang)(jiang)(jiang) FB 電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)阻器(qi) （110k） 換成(cheng)一個可變電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)位器(qi)，以實現輸(shu)(shu)出電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)調節，并將(jiang)(jiang)(jiang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)浮置電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)設置到(dao) 14V.該(gai)演示(shi)板(ban)設計利用(yong) LT1620 軌至軌電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)檢(jian)測放大器(qi)，結合 LTC1435 開關穩(wen)壓(ya)(ya)器(qi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)的(de)(de)(de)高效(xiao)率和低(di)壓(ya)(ya)差能力，形成(cheng)了一個效(xiao)率超過 95% 的(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)充(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)器(qi)，從而在(zai)(zai) 4A 充(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)時僅需要 0.5V 輸(shu)(shu)入至輸(shu)(shu)出電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)差。一個到(dao)地的(de)(de)(de)編程電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)設置電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)充(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu) （4A），該(gai)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)充(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)一直(zhi)是穩(wen)定(ding)的(de)(de)(de)，直(zhi)到(dao)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)達到(dao)預設的(de)(de)(de)浮置電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya) （在(zai)(zai)本文情(qing)況(kuang)下(xia)為(wei) 14V） 為(wei)止。隨著(zhu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)達到(dao)其(qi)滿(man)充(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)狀態，電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)的(de)(de)(de)編程將(jiang)(jiang)(jiang)自動轉入涓流(liu)(liu)充(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)狀態，并就電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)的(de)(de)(de)輸(shu)(shu)出電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)而言緩慢降低(di)充(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)。這減輕(qing)了由于恒定(ding)過沖(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)給電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)造成(cheng)的(de)(de)(de)壓(ya)(ya)力。

　　一(yi)個(ge)理想二極管電(dian)(dian)(dian)(dian)路設(she)計(ji)與 DC133A 充電(dian)(dian)(dian)(dian)系統(tong)的(de)輸出(chu)串聯，利用(yong)(yong)(yong) LTC4414 實現(xian)電(dian)(dian)(dian)(dian)路保護(hu)，并允許在充電(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)路以(yi)最小(xiao)損耗運(yun)行(xing)的(de)同時使用(yong)(yong)(yong)電(dian)(dian)(dian)(dian)池(chi)(chi)。這種自動電(dian)(dian)(dian)(dian)源(yuan)通路 （PowerPath？） 控制(zhi)(zhi)使外(wai)部(bu)設(she)備(bei)(bei)能(neng)(neng)(neng)夠自由地用(yong)(yong)(yong)太陽(yang)能(neng)(neng)(neng)電(dian)(dian)(dian)(dian)池(chi)(chi)板(ban)或電(dian)(dian)(dian)(dian)池(chi)(chi)供電(dian)(dian)(dian)(dian)。當太陽(yang)能(neng)(neng)(neng)電(dian)(dian)(dian)(dian)池(chi)(chi)板(ban)功率不足(zu)時，電(dian)(dian)(dian)(dian)路自動轉為(wei)從(cong)電(dian)(dian)(dian)(dian)池(chi)(chi)吸取功率。該電(dian)(dian)(dian)(dian)路設(she)計(ji)與 LTC4414 數據(ju)表第九頁(ye)上的(de)圖 2 類似。LTC4414 （8 引線 MSOP 封裝(zhuang)） 控制(zhi)(zhi)一(yi)個(ge)外(wai)部(bu) P 溝道(dao) MOSFET，以(yi)產生接近理想的(de)二極管功能(neng)(neng)(neng)，用(yong)(yong)(yong)于電(dian)(dian)(dian)(dian)源(yuan)切(qie)換。這允許多(duo)個(ge)電(dian)(dian)(dian)(dian)源(yuan)高效率進行(xing)“或” 操作(zuo)；在本文情況下，電(dian)(dian)(dian)(dian)源(yuan)是(shi)太陽(yang)能(neng)(neng)(neng)電(dian)(dian)(dian)(dian)池(chi)(chi)板(ban)和電(dian)(dian)(dian)(dian)池(chi)(chi)。當連接一(yi)個(ge)外(wai)部(bu)設(she)備(bei)(bei)時，電(dian)(dian)(dian)(dian)池(chi)(chi)和充電(dian)(dian)(dian)(dian)系統(tong)接受負載(zai)狀(zhuang)態。在無負載(zai)時，將(jiang)對電(dian)(dian)(dian)(dian)池(chi)(chi)充電(dian)(dian)(dian)(dian)。因此該設(she)計(ji)允許一(yi)起(qi)使用(yong)(yong)(yong)太陽(yang)能(neng)(neng)(neng)電(dian)(dian)(dian)(dian)池(chi)(chi)板(ban)和電(dian)(dian)(dian)(dian)池(chi)(chi)供電(dian)(dian)(dian)(dian)，同時運(yun)行(xing)電(dian)(dian)(dian)(dian)池(chi)(chi)充電(dian)(dian)(dian)(dian)過程(cheng)。這一(yi)部(bu)分(fen)沒有演示板(ban)可用(yong)(yong)(yong)，因此我按照(zhao)定制(zhi)(zhi)電(dian)(dian)(dian)(dian)路板(ban)上的(de)應(ying)用(yong)(yong)(yong)電(dian)(dian)(dian)(dian)路進行(xing)設(she)計(ji)。

　　電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)(liu)(liu)檢(jian)(jian)(jian)測系(xi)(xi)統(tong)與電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)串(chuan)聯，利用并聯檢(jian)(jian)(jian)測電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)器測量(liang)(liang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)的(de)(de)輸(shu)入(ru)充電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)(liu)(liu)和(he)(he)輸(shu)出(chu)放(fang)(fang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)(liu)(liu)，而無需斷(duan)開電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)。圖(tu) 3 的(de)(de)方框圖(tu)僅說明(ming)了(le)輸(shu)入(ru)充電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)(liu)(liu)。LTC6103 （采用 8 引(yin)線 MSOP 封裝，在(zai) 4V 至 60V 范圍內工(gong)作） 是一(yi)個(ge)雙路(lu)獨立電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)(liu)(liu)檢(jian)(jian)(jian)測放(fang)(fang)大器，可通過外部(bu)檢(jian)(jian)(jian)測電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)器監(jian)視電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)(liu)(liu)。該器件以(yi)(yi)(yi) mV 為單位測量(liang)(liang)和(he)(he)提(ti)供電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)充電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)和(he)(he)放(fang)(fang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)(liu)(liu)的(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)(liu)(liu)比(bi)率輸(shu)出(chu)。在(zai)本文情況下，它幫助(zhu)指示電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)充和(he)(he)放(fang)(fang)了(le)多少電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)量(liang)(liang)。這是一(yi)種以(yi)(yi)(yi)低(di)功率損耗讀取電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)(liu)(liu)的(de)(de)方法，這對保持(chi)一(yi)個(ge)高能效系(xi)(xi)統(tong)至關重要。我(wo)略微(wei)調節了(le) LTC6103 （DC1116A） 演示板以(yi)(yi)(yi)實現這一(yi)點。引(yin)腳(jiao)(jiao) 8 和(he)(he) 7 分(fen)別與進(jin)入(ru)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)的(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)(liu)(liu)通路(lu) +IN_A 和(he)(he) -IN_A 串(chuan)聯。這將提(ti)供進(jin)入(ru)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)的(de)(de)充電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)(liu)(liu)。引(yin)腳(jiao)(jiao) 6 和(he)(he) 5 相互掉換后反著連接(jie)，以(yi)(yi)(yi)測量(liang)(liang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)放(fang)(fang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)(liu)(liu)通路(lu)，+IN_B （引(yin)腳(jiao)(jiao) 5） 連接(jie)到(dao) -IN_A （引(yin)腳(jiao)(jiao) 7），-IN_B （引(yin)腳(jiao)(jiao) 6） 連接(jie)到(dao) +IN_A （引(yin)腳(jiao)(jiao) 8）。電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)器的(de)(de)值以(yi)(yi)(yi) 10 為倍數改(gai)變和(he)(he)調節，以(yi)(yi)(yi)便在(zai) 0.1Ω 并聯檢(jian)(jian)(jian)測電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)(zu)器與電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)串(chuan)聯時，輸(shu)出(chu)以(yi)(yi)(yi) 100mV/A 變化。圖(tu) 5 中的(de)(de)萬用表顯示整(zheng)個(ge)系(xi)(xi)統(tong)的(de)(de)結(jie)果。太陽能電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)板輸(shu)出(chu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)是 17.11V，電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)為 12.95V，充電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)(liu)(liu)是 3.58A.

　　圖 5：萬用表顯示 17.11V 太陽能電池板輸出，12.95V 電池充電電壓；3.58A電池充電電流

ADC 和微控(kong)制器讀(du)數

　　我決定，每次檢查(cha)電路是否正常運行時不使(shi)用電壓表(biao)(biao)，因為(wei)電壓表(biao)(biao)在沙漠中難(nan)以攜帶。為(wei)了避(bi)免攜帶多(duo)個萬用表(biao)(biao)，我用一個微控(kong)制器和 ADC 來讀取系統的電壓值，并在一般的 LCD 顯(xian)示屏上顯(xian)示信息。這(zhe)種方法可就電路性能提供實(shi)時數據，而(er)無需連接幾個萬用表(biao)(biao)。

　　我(wo)使用 DC590B 演示板和(he)(he) LTC2418 8信(xin)道(dao) / 16 信(xin)道(dao) 24 位 ADC 演示板 DC571A.我(wo)的(de)(de)(de)(de)(de)(de)同事(shi) Mark Thoren 給了我(wo) PIC 微控制器的(de)(de)(de)(de)(de)(de)嵌入(ru)(ru)式源(yuan)代(dai)碼樣(yang)本(ben)，我(wo)微調了這(zhe)個源(yuan)代(dai)碼樣(yang)本(ben)，以跨 LTC2418 上 ADC 的(de)(de)(de)(de)(de)(de)不同通道(dao)對電(dian)壓(ya)采樣(yang)，并以可接(jie)受的(de)(de)(de)(de)(de)(de)分辨率、準(zhun)確地讀出(chu)(chu) mV 范圍的(de)(de)(de)(de)(de)(de)電(dian)壓(ya)值。既然基準(zhun)電(dian)壓(ya)的(de)(de)(de)(de)(de)(de)最(zui)大范圍是 2.5V，那(nei)么我(wo)用一種電(dian)壓(ya)分壓(ya)器方法(fa)來按比例將電(dian)壓(ya)降低(di)到 mV 范圍，以在(zai)(zai)(zai) ADC 上實現正確的(de)(de)(de)(de)(de)(de)測量。通道(dao)連接(jie)到單個有(you)關的(de)(de)(de)(de)(de)(de)輸(shu)入(ru)(ru)和(he)(he)輸(shu)出(chu)(chu)電(dian)壓(ya)上，包括電(dian)流(liu)檢測電(dian)壓(ya)。這(zhe)么做非(fei)常成(cheng)功(gong)(gong)，無需多(duo)個萬用表。圖 6 是一個有(you)關這(zhe)個 LCD 顯(xian)示屏的(de)(de)(de)(de)(de)(de)全功(gong)(gong)能系統的(de)(de)(de)(de)(de)(de)例子。我(wo)在(zai)(zai)(zai) LCD 上得到的(de)(de)(de)(de)(de)(de)最(zui)后(hou)的(de)(de)(de)(de)(de)(de)顯(xian)示提(ti)供了有(you)關以下(xia)電(dian)壓(ya)的(de)(de)(de)(de)(de)(de)信(xin)息：變(bian)化的(de)(de)(de)(de)(de)(de)太(tai)陽能電(dian)源(yuan)電(dian)壓(ya) Vs、充(chong)電(dian)電(dian)路(lu)電(dian)壓(ya) Vc、電(dian)池(chi)電(dian)壓(ya) Vb、以及電(dian)池(chi)上的(de)(de)(de)(de)(de)(de)輸(shu)入(ru)(ru)充(chong)電(dian)/放電(dian)電(dian)流(liu) C 和(he)(he) D.在(zai)(zai)(zai)本(ben)文情況下(xia)，是“C”，它(ta)在(zai)(zai)(zai)充(chong)電(dian)。放電(dian)時，程(cheng)序(xu)將改變(bian)到“D”。

　　圖 6:LCD 讀數：Vs （太陽能電(dian)池板電(dian)壓(ya)(ya)）；Vc （充電(dian)電(dian)路電(dian)壓(ya)(ya)）；Vb （電(dian)池電(dian)壓(ya)(ya)）；C = 充電(dian)電(dian)流 （4.3A），用DC590B PIC 微控(kong)制器控(kong)制；用 LTC2418 演示板 DC571 ADC 讀取電(dian)壓(ya)(ya)，該演示板由 LTM4601演示板 DC1041A 微型模(mo)塊降壓(ya)(ya)型穩壓(ya)(ya)器供電(dian)。

　　注意，DC590B 演示(shi)板不是(shi)靠 12V 軌供(gong)電(dian)(dian)，而(er)是(shi)靠 5V 軌供(gong)電(dian)(dian)。需(xu)要(yao)一個(ge)降壓(ya)(ya)(ya)(ya)型(xing)穩壓(ya)(ya)(ya)(ya)器將電(dian)(dian)壓(ya)(ya)(ya)(ya)從電(dian)(dian)池(chi)的 12V 降低到 5V.這(zhe)個(ge)降壓(ya)(ya)(ya)(ya)型(xing)穩壓(ya)(ya)(ya)(ya)器將必須是(shi)高(gao)效率的，因為電(dian)(dian)源將來自太陽能(neng)電(dian)(dian)池(chi)板和(he)電(dian)(dian)池(chi)，我不想(xiang)因運行 LCD 顯示(shi)屏和(he)微控(kong)制器而(er)耗費(fei)大量功率。我使用 LTM4601 微型(xing)模塊 DC/DC 開關穩壓(ya)(ya)(ya)(ya)器演示(shi)板 DC1041A.

　　LTM4601 是一(yi)個(ge) LGA 封裝的 15mm x 15mm x 2.8mm 微型(xing)模塊 DC/DC 開關穩壓(ya)器，在 12A 最(zui)大(da)負載(zai)電(dian)流時，輸(shu)(shu)入為 4.5V 至 20V，輸(shu)(shu)出(chu)為 0.6V 至 5V.LTM4601 的設計使得(de)非常容易從 12V 電(dian)池(chi)提(ti)供一(yi)個(ge)穩定的 5V 輸(shu)(shu)出(chu)。該微型(xing)模塊包括所有控(kong)制支持(chi)組件(jian)，如電(dian)阻器、電(dian)容器、MOSFET 和電(dian)感器。在這個(ge)系(xi)統中，效率大(da)約為 90%，使用(yong)最(zui)小的電(dian)池(chi)電(dian)流，極(ji)大(da)地延長了電(dian)池(chi)壽命。更(geng)容易的是，輸(shu)(shu)出(chu)電(dian)壓(ya)用(yong)一(yi)個(ge)電(dian)阻器設置，如果我需(xu)要一(yi)個(ge)不(bu)同(tong)的電(dian)壓(ya)軌 （例如 3.3V、2.5V、1.8V、1.5V 和 1.2V），那么在演示板上用(yong)一(yi)條(tiao)跨接線可以(yi)非常容易地改變(bian)這個(ge)輸(shu)(shu)出(chu)電(dian)壓(ya)。

　　總之，兩塊(kuai) BP 太(tai)(tai)陽(yang)能電(dian)(dian)池(chi)(chi)板，每塊(kuai)在 4A 電(dian)(dian)流(liu)時都有 0 至(zhi) 20V 的輸出(chu)，這兩塊(kuai)太(tai)(tai)陽(yang)能電(dian)(dian)池(chi)(chi)板由(you) 20V 輸出(chu)的 LTM4607 降壓/升(sheng)壓型(xing)微(wei)型(xing)模塊(kuai)開關穩壓器(qi)(qi)調節(jie)，然后(hou)再到(dao) 14V 輸入的 LTC1435/LT1620 電(dian)(dian)池(chi)(chi)充電(dian)(dian)器(qi)(qi)，通過一個理想二極管 MOSFET 控制(zhi)器(qi)(qi) LTC4414、一個串聯的電(dian)(dian)流(liu)檢測放大器(qi)(qi) LTC6103，最終進入電(dian)(dian)池(chi)(chi)；以穩定的 4A 電(dian)(dian)流(liu)充電(dian)(dian)。在這個設計中(zhong)，由(you) LTC2418 在不同的級(ji)獲取 ADC 讀數，并將讀數送(song)至(zhi)由(you) LTM4601 微(wei)型(xing)模塊(kuai)開關穩壓器(qi)(qi)供電(dian)(dian)的 DC590B 演示(shi)板微(wei)控制(zhi)器(qi)(qi)，以在 LCD 上顯示(shi)結果。圖 7 顯示(shi)正在運行的整個系統。

　　圖 7：運行(xing)中的(de)整個系統設計(ji)

　　噴霧系統的機械設計

　　有(you)了(le)一(yi)個(ge)正常工作的太(tai)陽能(neng)充電器(qi)和穩定(ding)的 12V 輸出，我就準備好著手組(zu)裝(zhuang)噴(pen)霧系統了(le)。去一(yi)趟五金店就得到(dao)了(le)我需要的材料：艙底污水(shui)(shui)泵(beng)(beng)、水(shui)(shui)龍帶連接器(qi)、水(shui)(shui)龍帶夾具、轉接器(qi)和噴(pen)霧系統。水(shui)(shui)龍帶長約(yue) 15 英尺，擰在轉接器(qi)螺釘上，用(yong)水(shui)(shui)龍帶夾具固定(ding)到(dao)水(shui)(shui)泵(beng)(beng)上，噴(pen)霧系統固定(ding)在末端，有(you) 5 個(ge)噴(pen)霧嘴。底艙污水(shui)(shui)泵(beng)(beng)靠(kao)最大(da)值為 12V 的電壓運(yun)行(xing)，水(shui)(shui)壓可以(yi)通(tong)過降低(di)電壓來控制。

　　為了(le)實現靈活性，我安裝了(le)一個(ge)(ge)穩壓(ya)器(qi)(qi)(qi)，該穩壓(ya)器(qi)(qi)(qi)可以接受 12V 輸入(ru)，并將輸入(ru)轉換成可變的(de) 12V 輸出。這要求 LTM4607 設計有(you)降壓(ya)/升壓(ya)特性。該器(qi)(qi)(qi)件使用(yong)一個(ge)(ge)反饋電(dian)阻(zu)器(qi)(qi)(qi)控制輸出電(dian)壓(ya)。一個(ge)(ge) 50k 的(de)可變旋(xuan)鈕電(dian)位器(qi)(qi)(qi)取代了(le)電(dian)阻(zu)器(qi)(qi)(qi)，從而非常(chang)容易控制 0.8V 至(zhi) 12V 的(de)輸出。還串聯了(le)一個(ge)(ge) 5.62k 的(de)電(dian)阻(zu)器(qi)(qi)(qi)，以限制輸出電(dian)壓(ya)，保持輸出低于(yu) 15V.該設計通過旋(xuan)轉一個(ge)(ge)旋(xuan)鈕實現了(le)水壓(ya)控制。

　　然后，我(wo)就(jiu)可以測試我(wo)的(de)全功能(neng)噴(pen)霧系統了(le)。結果，水(shui)泵導致最大約(yue) 6A 的(de)電(dian)池(chi)(chi)放電(dian)電(dian)流(liu)，這意味著，在峰值輸出時，水(shui)泵約(yue)從每塊太陽能(neng)電(dian)池(chi)(chi)板獲得 4A 電(dian)流(liu)。控制水(shui)泵速度和壓力的(de)好處是，我(wo)可以將(jiang)壓力降(jiang)到足夠(gou)(gou)低(di)(di)，以降(jiang)低(di)(di)電(dian)池(chi)(chi)的(de)放電(dian)電(dian)流(liu)，并全部靠(kao)太陽能(neng)電(dian)池(chi)(chi)板運行(xing)(xing)水(shui)泵，以節省電(dian)池(chi)(chi)電(dian)量，這樣做(zuo)非常有效。通過這種方法，我(wo)們能(neng)夠(gou)(gou)在營地全天運行(xing)(xing)噴(pen)霧系統，而(er)不必(bi)擔心電(dian)池(chi)(chi)放電(dian)，耽誤(wu)夜(ye)間用(yong)于 LED 照明系統。

　　LED 照明

　　隨著電(dian)(dian)(dian)(dian)源的(de)(de)完成(cheng)，我就(jiu)可(ke)以(yi)增加電(dian)(dian)(dian)(dian)路(lu)，在晚上高效(xiao)率地提(ti)供(gong)照(zhao)明(ming)了(le)。LED 足(zu)夠亮(liang)，可(ke)以(yi)照(zhao)亮(liang)房間，這在以(yi)前(qian)是不可(ke)想象的(de)(de)，但是新(xin)的(de)(de)技術(shu)進步已經為 LED 照(zhao)明(ming)的(de)(de)新(xin)時(shi)(shi)代創造了(le)條(tiao)件。尤其(qi)是，PhilipsLumileds Luxeon LED 在 1000mA 時(shi)(shi)可(ke)以(yi)提(ti)供(gong)超過 100 流(liu)明(ming)的(de)(de)光。我配(pei)備了(le)一(yi)個(ge)(ge) LumiLED 陣(zhen)列(lie)，使用 LTC3475 （16 引線 TSSOP 耐熱增強型封裝） 雙路(lu) 1.5A 恒定(ding)電(dian)(dian)(dian)(dian)流(liu) LED 驅(qu)動器(qi) DC923A 演示(shi)板。它設(she)計成(cheng)用一(yi)個(ge)(ge)寬范圍輸入電(dian)(dian)(dian)(dian)壓(ya) （4V 至 30V） 驅(qu)動兩個(ge)(ge)信道(dao)，每個(ge)(ge)信道(dao) 1.5A.12V 電(dian)(dian)(dian)(dian)池直接(jie)(jie)(jie)連接(jie)(jie)(jie)到演示(shi)板的(de)(de)輸入，為每個(ge)(ge)通(tong)道(dao) 3 個(ge)(ge)串聯的(de)(de) LED 燈(deng)供(gong)電(dian)(dian)(dian)(dian)，當兩個(ge)(ge)通(tong)道(dao)都接(jie)(jie)(jie)通(tong)時(shi)(shi)，總共(gong)有 6 個(ge)(ge) LED.這些 LED 出(chu)奇地亮(liang)，用一(yi)塊柔光布遮上時(shi)(shi)，足(zu)夠照(zhao)亮(liang)我們整個(ge)(ge)營地。晚上的(de)(de)放(fang)電(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)流(liu)全部來自電(dian)(dian)(dian)(dian)池，因為太陽能電(dian)(dian)(dian)(dian)池板夜間提(ti)供(gong)零電(dian)(dian)(dian)(dian)力。以(yi) 2A 的(de)(de)總放(fang)電(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)流(liu)，可(ke)以(yi)整晚為這些燈(deng)供(gong)電(dian)(dian)(dian)(dian)。到接(jie)(jie)(jie)近中(zhong)午或(huo)偏下(xia)午時(shi)(shi)，電(dian)(dian)(dian)(dian)池再次充滿電(dian)(dian)(dian)(dian)，為給噴(pen)霧系統供(gong)電(dian)(dian)(dian)(dian)做好了(le)準備，在早午餐后，噴(pen)霧系統就(jiu)可(ke)以(yi)讓我們感到涼(liang)爽(shuang)了(le)。