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)有 3 周(zhou)時間完成設(she)計。我(wo)向(xiang)朋友(you) Simon 請求(qiu)幫助，Simon 以(yi)前(qian)用(yong)凌(ling)力爾(er)特(te)公司的 IC 搞過(guo)太陽能供電設(she)計。除(chu)了一臺顯示工(gong)作原(yuan)理的樣機(ji)(ji)，Simon 還給了我(wo)一份原(yuan)理圖，這臺樣機(ji)(ji)從未連上太陽能電池板測(ce)試過(guo)，但在(zai)實(shi)驗室做過(guo)仿真(zhen)。我(wo)很(hen)興奮，有興趣用(yong)真(zhen)實(shi)的太陽能電池板測(ce)試這個(ge)設(she)計，我(wo)們準備對樣機(ji)(ji)進行像樣的測(ce)試。

　　一位朋友(you)借給我兩(liang)塊(kuai) BP 太(tai)陽(yang)能(neng)(neng)電(dian)(dian)池(chi)板(ban)(ban) （BP380U）。在大約 20V 最(zui)高輸(shu)出(chu)電(dian)(dian)壓和 4A 最(zui)大輸(shu)出(chu)電(dian)(dian)流(liu)(liu)時(shi)，每塊(kuai)電(dian)(dian)池(chi)板(ban)(ban)的峰(feng)(feng)值功率都是 80W （實際規(gui)格為，在 80W 最(zui)大功率時(shi)，電(dian)(dian)壓為 17.6V，電(dian)(dian)流(liu)(liu)為 4.55A）。把這(zhe)(zhe)兩(liang)塊(kuai)太(tai)陽(yang)能(neng)(neng)電(dian)(dian)池(chi)板(ban)(ban)合起(qi)來，我希望(wang)在太(tai)陽(yang)光直(zhi)接直(zhi)射在電(dian)(dian)池(chi)板(ban)(ban)上時(shi)，在峰(feng)(feng)值條件下能(neng)(neng)有 8A 的總電(dian)(dian)流(liu)(liu)。太(tai)陽(yang)能(neng)(neng)電(dian)(dian)池(chi)板(ban)(ban)連接到(dao) Simon 的樣機上沒(mei)有幾分鐘，系(xi)統(tong)就充分運轉(zhuan)了(le)(le) （圖(tu) 1 和圖(tu) 2）。通(tong)過(guo)對樣機的初步(bu)測試(shi)，查明了(le)(le)幾個故障，后來這(zhe)(zhe)給我們節(jie)省了(le)(le)大量時(shi)間。

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

　　圖 2：最初的太陽能(neng)充電電路樣(yang)機，采用(yong)(yong) 12V 海上用(yong)(yong)深周期電池 。

　　樣(yang)機(ji)運行良好，因此我(wo)購買了(le)幾塊凌力爾特公司的(de)演示板，并稍作修改以使其更適合重新(xin)(xin)設(she)計過的(de)系統(tong)規格要求。我(wo)保(bao)持樣(yang)機(ji)作為備份和參考(kao)，同時我(wo)設(she)計了(le)一(yi)個新(xin)(xin)系統(tong)。我(wo)們解決了(le)一(yi)些(xie)故障(zhang)后，通(tong)過這些(xie)修改改善(shan)了(le)原來的(de)樣(yang)機(ji)。總之，架構設(she)計仍然(ran)是相同的(de)：用 0 至 20V 的(de)太(tai)陽能電(dian)(dian)池板，以 4A 的(de)恒定電(dian)(dian)流(liu)給一(yi)個 12V 的(de)電(dian)(dian)池充電(dian)(dian),

   太陽能電池充電器系統設計(ji)

　　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 3：系(xi)統(tong)設計方框圖

　　圖 4：最終的太陽能充電器電路

　　視太(tai)陽的(de)位置不同(tong)(tong)而不同(tong)(tong)，太(tai)陽能電(dian)池(chi)板(ban)最(zui)初的(de)輸(shu)(shu)出電(dian)壓(ya)(ya)在 0V 到(dao) 20V 之(zhi)間變化，那么就用一個能接(jie)受(shou)這(zhe)么寬輸(shu)(shu)出范圍的(de)穩壓(ya)(ya)器(qi)，并保持吸取低的(de)電(dian)流(liu) （每個電(dian)池(chi)板(ban)上的(de)輸(shu)(shu)入電(dian)流(liu)最(zui)大值(zhi)都是(shi) 4A），同(tong)(tong)時調節一個固定(ding)的(de)輸(shu)(shu)出電(dian)壓(ya)(ya)。這(zhe)是(shi)在 DC1198A-B 演示板(ban)上用凌力爾(er)特公(gong)司的(de)微型(xing)模塊 （μModule） DC/DC 降(jiang)壓(ya)(ya)-升壓(ya)(ya)型(xing)開關(guan)穩壓(ya)(ya)器(qi) LTM4607 實現的(de)。

　　LTM4607 是(shi)(shi)一(yi)個(ge)(ge)小型 LGA 封(feng)裝 （15mm x 15mm x 2.8mm） 的(de)(de)(de)芯片，其(qi)中包括一(yi)個(ge)(ge)復(fu)雜(za)的(de)(de)(de)降壓(ya)-升(sheng)(sheng)壓(ya)型 DC/DC 開關(guan)穩壓(ya)器(qi)(qi)所(suo)需的(de)(de)(de)所(suo)有(you)支(zhi)持控制(zhi)組(zu)件。復(fu)雜(za)的(de)(de)(de)開關(guan)控制(zhi)電路和 FET 內置到微(wei)(wei)型模(mo)(mo)塊穩壓(ya)器(qi)(qi)中，從而使該(gai)(gai)器(qi)(qi)件非常容易(yi)使用。結(jie)果是(shi)(shi)僅(jin)需一(yi)個(ge)(ge)微(wei)(wei)型模(mo)(mo)塊穩壓(ya)器(qi)(qi)、電感器(qi)(qi)以及幾個(ge)(ge)電容器(qi)(qi)和電阻器(qi)(qi)就完成(cheng)簡潔規則的(de)(de)(de)布局(ju)。4.5V 至(zhi) 36V 的(de)(de)(de)寬(kuan)輸入(ru)電壓(ya)范(fan)(fan)圍(wei)(wei)至(zhi)固(gu)定(ding) 20V 輸出(chu)(chu)(chu) （范(fan)(fan)圍(wei)(wei)為 0.8V 至(zhi) 24V） 對于太陽能電池(chi)板(ban)(ban)的(de)(de)(de)特性 （0 至(zhi) 20V 輸出(chu)(chu)(chu)） 正合(he)適，而且該(gai)(gai)器(qi)(qi)件能加(jia)載高(gao)達 5A 的(de)(de)(de)升(sheng)(sheng)壓(ya)模(mo)(mo)式(shi)和 10A 的(de)(de)(de)降壓(ya)模(mo)(mo)式(shi)。在太陽能電池(chi)板(ban)(ban)峰值功率(lv)時，20V 輸入(ru)至(zhi) 20V/2.5A 輸出(chu)(chu)(chu)的(de)(de)(de)效(xiao)率(lv)是(shi)(shi) 91%，而且積極(ji)利用了降壓(ya)-升(sheng)(sheng)壓(ya)型寬(kuan)范(fan)(fan)圍(wei)(wei)輸入(ru)的(de)(de)(de)好處。就這(zhe)個(ge)(ge)系(xi)統設計的(de)(de)(de)目的(de)(de)(de)而言，輸出(chu)(chu)(chu)調節到 20V，用這(zhe)個(ge)(ge)輸出(chu)(chu)(chu)給 LTC1435/LT1620 高(gao)效(xiao)率(lv)、低壓(ya)差電池(chi)充電器(qi)(qi)系(xi)統供(gong)電。

　　在(zai) 14V 穩(wen)定(ding)(ding)電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)時(shi)，LTC1435/LT1620 演(yan)示板(ban) （DC133A） 將充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)控制到(dao)穩(wen)定(ding)(ding)的(de)(de) 4A.該演(yan)示板(ban)與 LT1620 數(shu)據(ju)表(biao)第(di)一(yi)(yi)頁上的(de)(de)應(ying)用電(dian)(dian)(dian)(dian)(dian)(dian)路(lu)類似，我將 FB 電(dian)(dian)(dian)(dian)(dian)(dian)阻器 （110k） 換成(cheng)一(yi)(yi)個可(ke)變電(dian)(dian)(dian)(dian)(dian)(dian)位器，以(yi)實(shi)現輸(shu)出(chu)電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)調節，并將電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)浮置(zhi)(zhi)電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)設(she)(she)置(zhi)(zhi)到(dao) 14V.該演(yan)示板(ban)設(she)(she)計利用 LT1620 軌(gui)至(zhi)(zhi)軌(gui)電(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)檢測放大器，結(jie)合(he) LTC1435 開(kai)關穩(wen)壓(ya)器電(dian)(dian)(dian)(dian)(dian)(dian)路(lu)的(de)(de)高效率和低(di)壓(ya)差能力(li)，形成(cheng)了一(yi)(yi)個效率超過 95% 的(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)器，從而(er)在(zai) 4A 充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)時(shi)僅需要 0.5V 輸(shu)入(ru)(ru)至(zhi)(zhi)輸(shu)出(chu)電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)差。一(yi)(yi)個到(dao)地的(de)(de)編(bian)程電(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)設(she)(she)置(zhi)(zhi)電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu) （4A），該電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)一(yi)(yi)直是穩(wen)定(ding)(ding)的(de)(de)，直到(dao)電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)達(da)到(dao)預設(she)(she)的(de)(de)浮置(zhi)(zhi)電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya) （在(zai)本文情況下(xia)為(wei) 14V） 為(wei)止(zhi)。隨著電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)達(da)到(dao)其滿充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)狀態(tai)，電(dian)(dian)(dian)(dian)(dian)(dian)路(lu)的(de)(de)編(bian)程將自動(dong)轉(zhuan)入(ru)(ru)涓流(liu)(liu)(liu)充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)狀態(tai)，并就電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)的(de)(de)輸(shu)出(chu)電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)而(er)言(yan)緩(huan)慢降低(di)充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)。這減輕了由于恒定(ding)(ding)過沖(chong)電(dian)(dian)(dian)(dian)(dian)(dian)給電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)造成(cheng)的(de)(de)壓(ya)力(li)。

　　一個理(li)想二極(ji)管(guan)電(dian)(dian)(dian)(dian)(dian)路(lu)(lu)設(she)計(ji)與(yu) DC133A 充電(dian)(dian)(dian)(dian)(dian)系(xi)統的(de)輸出串聯，利用(yong)(yong) LTC4414 實現電(dian)(dian)(dian)(dian)(dian)路(lu)(lu)保護(hu)，并(bing)允許(xu)(xu)在充電(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)路(lu)(lu)以最小損(sun)耗運行(xing)(xing)的(de)同時(shi)(shi)使用(yong)(yong)電(dian)(dian)(dian)(dian)(dian)池(chi)(chi)。這種自動(dong)電(dian)(dian)(dian)(dian)(dian)源(yuan)通路(lu)(lu) （PowerPath？） 控制使外部設(she)備能(neng)夠自由地用(yong)(yong)太陽能(neng)電(dian)(dian)(dian)(dian)(dian)池(chi)(chi)板或(huo)電(dian)(dian)(dian)(dian)(dian)池(chi)(chi)供電(dian)(dian)(dian)(dian)(dian)。當太陽能(neng)電(dian)(dian)(dian)(dian)(dian)池(chi)(chi)板功(gong)率不足時(shi)(shi)，電(dian)(dian)(dian)(dian)(dian)路(lu)(lu)自動(dong)轉為從電(dian)(dian)(dian)(dian)(dian)池(chi)(chi)吸取(qu)功(gong)率。該電(dian)(dian)(dian)(dian)(dian)路(lu)(lu)設(she)計(ji)與(yu) LTC4414 數據表第(di)九頁(ye)上(shang)(shang)的(de)圖 2 類(lei)似。LTC4414 （8 引(yin)線 MSOP 封裝） 控制一個外部 P 溝(gou)道 MOSFET，以產生接近(jin)理(li)想的(de)二極(ji)管(guan)功(gong)能(neng)，用(yong)(yong)于電(dian)(dian)(dian)(dian)(dian)源(yuan)切換。這允許(xu)(xu)多個電(dian)(dian)(dian)(dian)(dian)源(yuan)高效率進(jin)行(xing)(xing)“或(huo)” 操作(zuo)；在本文(wen)情況(kuang)下，電(dian)(dian)(dian)(dian)(dian)源(yuan)是太陽能(neng)電(dian)(dian)(dian)(dian)(dian)池(chi)(chi)板和(he)電(dian)(dian)(dian)(dian)(dian)池(chi)(chi)。當連接一個外部設(she)備時(shi)(shi)，電(dian)(dian)(dian)(dian)(dian)池(chi)(chi)和(he)充電(dian)(dian)(dian)(dian)(dian)系(xi)統接受負載狀態。在無負載時(shi)(shi)，將對(dui)電(dian)(dian)(dian)(dian)(dian)池(chi)(chi)充電(dian)(dian)(dian)(dian)(dian)。因此(ci)該設(she)計(ji)允許(xu)(xu)一起使用(yong)(yong)太陽能(neng)電(dian)(dian)(dian)(dian)(dian)池(chi)(chi)板和(he)電(dian)(dian)(dian)(dian)(dian)池(chi)(chi)供電(dian)(dian)(dian)(dian)(dian)，同時(shi)(shi)運行(xing)(xing)電(dian)(dian)(dian)(dian)(dian)池(chi)(chi)充電(dian)(dian)(dian)(dian)(dian)過程(cheng)。這一部分沒有演示板可用(yong)(yong)，因此(ci)我按照定制電(dian)(dian)(dian)(dian)(dian)路(lu)(lu)板上(shang)(shang)的(de)應用(yong)(yong)電(dian)(dian)(dian)(dian)(dian)路(lu)(lu)進(jin)行(xing)(xing)設(she)計(ji)。

　　電(dian)(dian)(dian)(dian)(dian)(dian)流(liu)檢(jian)(jian)測(ce)系(xi)統(tong)與(yu)電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)串(chuan)聯(lian)(lian)，利用(yong)并聯(lian)(lian)檢(jian)(jian)測(ce)電(dian)(dian)(dian)(dian)(dian)(dian)阻器測(ce)量(liang)電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)的(de)輸(shu)(shu)入充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)流(liu)和(he)輸(shu)(shu)出(chu)(chu)放電(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)流(liu)，而無(wu)需(xu)斷開電(dian)(dian)(dian)(dian)(dian)(dian)路(lu)。圖(tu)(tu) 3 的(de)方框圖(tu)(tu)僅說明了輸(shu)(shu)入充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)流(liu)。LTC6103 （采用(yong) 8 引(yin)(yin)線(xian) MSOP 封(feng)裝，在(zai)(zai) 4V 至 60V 范圍內(nei)工作） 是一(yi)個(ge)雙(shuang)路(lu)獨立(li)電(dian)(dian)(dian)(dian)(dian)(dian)流(liu)檢(jian)(jian)測(ce)放大器，可(ke)通(tong)過(guo)外部檢(jian)(jian)測(ce)電(dian)(dian)(dian)(dian)(dian)(dian)阻器監視電(dian)(dian)(dian)(dian)(dian)(dian)流(liu)。該器件以(yi) mV 為(wei)單位測(ce)量(liang)和(he)提(ti)供電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)和(he)放電(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)流(liu)的(de)電(dian)(dian)(dian)(dian)(dian)(dian)流(liu)比率輸(shu)(shu)出(chu)(chu)。在(zai)(zai)本文情況下，它(ta)幫助指示(shi)電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)充(chong)(chong)(chong)和(he)放了多少電(dian)(dian)(dian)(dian)(dian)(dian)量(liang)。這(zhe)是一(yi)種以(yi)低(di)功率損耗讀取電(dian)(dian)(dian)(dian)(dian)(dian)流(liu)的(de)方法，這(zhe)對保持一(yi)個(ge)高能(neng)效系(xi)統(tong)至關重要(yao)。我略微調節(jie)了 LTC6103 （DC1116A） 演示(shi)板以(yi)實現(xian)這(zhe)一(yi)點。引(yin)(yin)腳(jiao)(jiao) 8 和(he) 7 分別與(yu)進入電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)的(de)電(dian)(dian)(dian)(dian)(dian)(dian)流(liu)通(tong)路(lu) +IN_A 和(he) -IN_A 串(chuan)聯(lian)(lian)。這(zhe)將(jiang)提(ti)供進入電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)的(de)充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)流(liu)。引(yin)(yin)腳(jiao)(jiao) 6 和(he) 5 相互掉換后反(fan)著(zhu)連接，以(yi)測(ce)量(liang)電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)放電(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)流(liu)通(tong)路(lu)，+IN_B （引(yin)(yin)腳(jiao)(jiao) 5） 連接到 -IN_A （引(yin)(yin)腳(jiao)(jiao) 7），-IN_B （引(yin)(yin)腳(jiao)(jiao) 6） 連接到 +IN_A （引(yin)(yin)腳(jiao)(jiao) 8）。電(dian)(dian)(dian)(dian)(dian)(dian)阻器的(de)值(zhi)以(yi) 10 為(wei)倍數改變(bian)和(he)調節(jie)，以(yi)便在(zai)(zai) 0.1Ω 并聯(lian)(lian)檢(jian)(jian)測(ce)電(dian)(dian)(dian)(dian)(dian)(dian)阻器與(yu)電(dian)(dian)(dian)(dian)(dian)(dian)路(lu)串(chuan)聯(lian)(lian)時，輸(shu)(shu)出(chu)(chu)以(yi) 100mV/A 變(bian)化。圖(tu)(tu) 5 中的(de)萬用(yong)表顯示(shi)整個(ge)系(xi)統(tong)的(de)結果。太陽(yang)能(neng)電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)板輸(shu)(shu)出(chu)(chu)電(dian)(dian)(dian)(dian)(dian)(dian)壓是 17.11V，電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)電(dian)(dian)(dian)(dian)(dian)(dian)壓為(wei) 12.95V，充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)流(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 和微控制器讀(du)數

　　我決定，每次檢(jian)查電(dian)(dian)(dian)路(lu)(lu)是否正常運(yun)行時不使用(yong)電(dian)(dian)(dian)壓表，因(yin)為電(dian)(dian)(dian)壓表在沙(sha)漠中難以攜(xie)帶(dai)。為了避免攜(xie)帶(dai)多個(ge)萬用(yong)表，我用(yong)一個(ge)微控制器和 ADC 來讀(du)取系統的(de)電(dian)(dian)(dian)壓值，并在一般的(de) LCD 顯(xian)示屏上顯(xian)示信息。這種方法可就電(dian)(dian)(dian)路(lu)(lu)性(xing)能提供實時數據，而(er)無需連接(jie)幾個(ge)萬用(yong)表。

　　我(wo)使用 DC590B 演(yan)示(shi)板和(he) LTC2418 8信(xin)道(dao)(dao)(dao) / 16 信(xin)道(dao)(dao)(dao) 24 位 ADC 演(yan)示(shi)板 DC571A.我(wo)的(de)(de)(de)(de)同事(shi) Mark Thoren 給(gei)了(le)我(wo) PIC 微(wei)控(kong)制器(qi)的(de)(de)(de)(de)嵌入式源代碼(ma)樣本(ben)，我(wo)微(wei)調(diao)了(le)這(zhe)個(ge)(ge)源代碼(ma)樣本(ben)，以跨 LTC2418 上(shang) ADC 的(de)(de)(de)(de)不同通道(dao)(dao)(dao)對電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)采樣，并以可接受的(de)(de)(de)(de)分辨率、準確地(di)讀出 mV 范圍(wei)的(de)(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)值。既然基準電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)的(de)(de)(de)(de)最大范圍(wei)是(shi)(shi) 2.5V，那(nei)么我(wo)用一種電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)分壓(ya)(ya)器(qi)方法來按(an)比例(li)將電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)降低到(dao) mV 范圍(wei)，以在 ADC 上(shang)實現正確的(de)(de)(de)(de)測量(liang)。通道(dao)(dao)(dao)連接到(dao)單(dan)個(ge)(ge)有關(guan)的(de)(de)(de)(de)輸(shu)入和(he)輸(shu)出電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)上(shang)，包括電(dian)(dian)(dian)(dian)(dian)(dian)(dian)流檢測電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)。這(zhe)么做非常成功，無需多個(ge)(ge)萬用表。圖 6 是(shi)(shi)一個(ge)(ge)有關(guan)這(zhe)個(ge)(ge) LCD 顯示(shi)屏的(de)(de)(de)(de)全功能系統的(de)(de)(de)(de)例(li)子。我(wo)在 LCD 上(shang)得到(dao)的(de)(de)(de)(de)最后的(de)(de)(de)(de)顯示(shi)提供(gong)了(le)有關(guan)以下(xia)(xia)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)的(de)(de)(de)(de)信(xin)息：變化的(de)(de)(de)(de)太陽能電(dian)(dian)(dian)(dian)(dian)(dian)(dian)源電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya) Vs、充電(dian)(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)路電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya) Vc、電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya) Vb、以及電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)上(shang)的(de)(de)(de)(de)輸(shu)入充電(dian)(dian)(dian)(dian)(dian)(dian)(dian)/放電(dian)(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)流 C 和(he) D.在本(ben)文情況下(xia)(xia)，是(shi)(shi)“C”，它在充電(dian)(dian)(dian)(dian)(dian)(dian)(dian)。放電(dian)(dian)(dian)(dian)(dian)(dian)(dian)時(shi)，程序將改變到(dao)“D”。

　　圖 6:LCD 讀(du)數：Vs （太(tai)陽(yang)能電(dian)(dian)池(chi)板(ban)電(dian)(dian)壓(ya)）；Vc （充電(dian)(dian)電(dian)(dian)路電(dian)(dian)壓(ya)）；Vb （電(dian)(dian)池(chi)電(dian)(dian)壓(ya)）；C = 充電(dian)(dian)電(dian)(dian)流 （4.3A），用DC590B PIC 微控制器(qi)控制；用 LTC2418 演示(shi)板(ban) DC571 ADC 讀(du)取電(dian)(dian)壓(ya)，該(gai)演示(shi)板(ban)由 LTM4601演示(shi)板(ban) DC1041A 微型(xing)模塊降壓(ya)型(xing)穩(wen)壓(ya)器(qi)供(gong)電(dian)(dian)。

　　注意(yi)，DC590B 演示板不(bu)是靠 12V 軌供(gong)電(dian)，而是靠 5V 軌供(gong)電(dian)。需要一(yi)個降壓(ya)(ya)型(xing)穩(wen)壓(ya)(ya)器(qi)(qi)將(jiang)電(dian)壓(ya)(ya)從電(dian)池(chi)(chi)的 12V 降低到(dao) 5V.這(zhe)個降壓(ya)(ya)型(xing)穩(wen)壓(ya)(ya)器(qi)(qi)將(jiang)必須是高(gao)效率(lv)的，因(yin)為電(dian)源將(jiang)來自太(tai)陽能電(dian)池(chi)(chi)板和(he)電(dian)池(chi)(chi)，我不(bu)想因(yin)運行(xing) LCD 顯示屏和(he)微控制(zhi)器(qi)(qi)而耗費(fei)大量(liang)功率(lv)。我使(shi)用 LTM4601 微型(xing)模(mo)塊 DC/DC 開關穩(wen)壓(ya)(ya)器(qi)(qi)演示板 DC1041A.

　　LTM4601 是(shi)(shi)一個(ge) LGA 封裝的(de) 15mm x 15mm x 2.8mm 微(wei)型模塊 DC/DC 開(kai)關穩(wen)壓(ya)(ya)器(qi)，在 12A 最(zui)大(da)負載(zai)電(dian)(dian)(dian)流時，輸(shu)入(ru)為(wei) 4.5V 至(zhi) 20V，輸(shu)出(chu)(chu)為(wei) 0.6V 至(zhi) 5V.LTM4601 的(de)設計使得非(fei)常(chang)容(rong)易從(cong) 12V 電(dian)(dian)(dian)池(chi)(chi)提(ti)供一個(ge)穩(wen)定的(de) 5V 輸(shu)出(chu)(chu)。該微(wei)型模塊包括所有控制支持組件(jian)，如(ru)(ru)電(dian)(dian)(dian)阻器(qi)、電(dian)(dian)(dian)容(rong)器(qi)、MOSFET 和(he)電(dian)(dian)(dian)感器(qi)。在這個(ge)系統(tong)中(zhong)，效率大(da)約為(wei) 90%，使用最(zui)小的(de)電(dian)(dian)(dian)池(chi)(chi)電(dian)(dian)(dian)流，極大(da)地(di)延長了電(dian)(dian)(dian)池(chi)(chi)壽命。更容(rong)易的(de)是(shi)(shi)，輸(shu)出(chu)(chu)電(dian)(dian)(dian)壓(ya)(ya)用一個(ge)電(dian)(dian)(dian)阻器(qi)設置，如(ru)(ru)果我(wo)需要一個(ge)不同(tong)的(de)電(dian)(dian)(dian)壓(ya)(ya)軌 （例如(ru)(ru) 3.3V、2.5V、1.8V、1.5V 和(he) 1.2V），那(nei)么(me)在演(yan)示(shi)板(ban)上用一條跨接(jie)線可(ke)以非(fei)常(chang)容(rong)易地(di)改變這個(ge)輸(shu)出(chu)(chu)電(dian)(dian)(dian)壓(ya)(ya)。

　　總之(zhi)，兩(liang)塊(kuai)(kuai) BP 太陽能電(dian)(dian)池(chi)板，每塊(kuai)(kuai)在(zai) 4A 電(dian)(dian)流(liu)時都有 0 至 20V 的(de)輸(shu)出(chu)(chu)，這兩(liang)塊(kuai)(kuai)太陽能電(dian)(dian)池(chi)板由(you)(you) 20V 輸(shu)出(chu)(chu)的(de) LTM4607 降壓(ya)/升壓(ya)型微型模塊(kuai)(kuai)開關(guan)穩(wen)壓(ya)器(qi)(qi)調(diao)節(jie)，然后(hou)再到 14V 輸(shu)入的(de) LTC1435/LT1620 電(dian)(dian)池(chi)充電(dian)(dian)器(qi)(qi)，通過一個(ge)理想二極管 MOSFET 控(kong)制器(qi)(qi) LTC4414、一個(ge)串聯的(de)電(dian)(dian)流(liu)檢測放大(da)器(qi)(qi) LTC6103，最終進入電(dian)(dian)池(chi)；以(yi)穩(wen)定的(de) 4A 電(dian)(dian)流(liu)充電(dian)(dian)。在(zai)這個(ge)設計中，由(you)(you) LTC2418 在(zai)不(bu)同的(de)級獲(huo)取 ADC 讀數，并將讀數送至由(you)(you) LTM4601 微型模塊(kuai)(kuai)開關(guan)穩(wen)壓(ya)器(qi)(qi)供電(dian)(dian)的(de) DC590B 演示板微控(kong)制器(qi)(qi)，以(yi)在(zai) LCD 上顯示結果。圖(tu) 7 顯示正在(zai)運(yun)行的(de)整個(ge)系(xi)統。

　　圖 7：運(yun)行中的整個系統設計

　　噴霧系統的機械設計

　　有了(le)一(yi)個(ge)正常工作的太陽能(neng)充電(dian)器(qi)和穩(wen)定的 12V 輸出(chu)，我(wo)就(jiu)(jiu)準備好著(zhu)手組(zu)裝噴霧(wu)系統了(le)。去一(yi)趟五金店(dian)就(jiu)(jiu)得到了(le)我(wo)需要的材(cai)料：艙(cang)(cang)底(di)污水(shui)(shui)(shui)泵、水(shui)(shui)(shui)龍(long)帶連接器(qi)、水(shui)(shui)(shui)龍(long)帶夾(jia)具、轉(zhuan)接器(qi)和噴霧(wu)系統。水(shui)(shui)(shui)龍(long)帶長約 15 英尺，擰在(zai)轉(zhuan)接器(qi)螺釘(ding)上(shang)，用水(shui)(shui)(shui)龍(long)帶夾(jia)具固定到水(shui)(shui)(shui)泵上(shang)，噴霧(wu)系統固定在(zai)末(mo)端，有 5 個(ge)噴霧(wu)嘴(zui)。底(di)艙(cang)(cang)污水(shui)(shui)(shui)泵靠最大值為 12V 的電(dian)壓(ya)運(yun)行，水(shui)(shui)(shui)壓(ya)可以(yi)通過(guo)降(jiang)低電(dian)壓(ya)來(lai)控制(zhi)。

　　為了(le)(le)實(shi)現(xian)靈活性，我安(an)裝了(le)(le)一(yi)(yi)個穩(wen)壓(ya)(ya)(ya)器(qi)，該(gai)穩(wen)壓(ya)(ya)(ya)器(qi)可(ke)以接受(shou) 12V 輸(shu)(shu)(shu)入(ru)，并將輸(shu)(shu)(shu)入(ru)轉(zhuan)換成(cheng)可(ke)變的 12V 輸(shu)(shu)(shu)出。這要求 LTM4607 設(she)計有降壓(ya)(ya)(ya)/升壓(ya)(ya)(ya)特性。該(gai)器(qi)件(jian)使用一(yi)(yi)個反饋電(dian)(dian)阻器(qi)控(kong)制輸(shu)(shu)(shu)出電(dian)(dian)壓(ya)(ya)(ya)。一(yi)(yi)個 50k 的可(ke)變旋鈕(niu)電(dian)(dian)位器(qi)取代了(le)(le)電(dian)(dian)阻器(qi)，從(cong)而非常容易控(kong)制 0.8V 至 12V 的輸(shu)(shu)(shu)出。還(huan)串聯了(le)(le)一(yi)(yi)個 5.62k 的電(dian)(dian)阻器(qi)，以限制輸(shu)(shu)(shu)出電(dian)(dian)壓(ya)(ya)(ya)，保持輸(shu)(shu)(shu)出低(di)于 15V.該(gai)設(she)計通過旋轉(zhuan)一(yi)(yi)個旋鈕(niu)實(shi)現(xian)了(le)(le)水壓(ya)(ya)(ya)控(kong)制。

　　然后，我就可(ke)以(yi)(yi)測試我的全(quan)(quan)(quan)功能(neng)(neng)噴霧(wu)系統了。結果，水泵(beng)導致最大約 6A 的電(dian)(dian)池(chi)放電(dian)(dian)電(dian)(dian)流(liu)(liu)，這(zhe)意味著(zhu)，在峰(feng)值輸出時，水泵(beng)約從每塊太(tai)陽能(neng)(neng)電(dian)(dian)池(chi)板(ban)(ban)獲得 4A 電(dian)(dian)流(liu)(liu)。控制水泵(beng)速度和(he)壓(ya)(ya)力的好處是(shi)，我可(ke)以(yi)(yi)將壓(ya)(ya)力降到足夠低，以(yi)(yi)降低電(dian)(dian)池(chi)的放電(dian)(dian)電(dian)(dian)流(liu)(liu)，并全(quan)(quan)(quan)部靠太(tai)陽能(neng)(neng)電(dian)(dian)池(chi)板(ban)(ban)運行水泵(beng)，以(yi)(yi)節省電(dian)(dian)池(chi)電(dian)(dian)量，這(zhe)樣做非常有效。通過這(zhe)種方法，我們能(neng)(neng)夠在營地全(quan)(quan)(quan)天運行噴霧(wu)系統，而不必擔心電(dian)(dian)池(chi)放電(dian)(dian)，耽(dan)誤夜(ye)間(jian)用于 LED 照明系統。

　　LED 照明

　　隨著電(dian)(dian)(dian)(dian)(dian)源的(de)完成，我就(jiu)可(ke)以(yi)增(zeng)加(jia)電(dian)(dian)(dian)(dian)(dian)路(lu)，在(zai)晚(wan)上(shang)高效率地(di)提供(gong)照明(ming)了(le)。LED 足夠亮(liang)，可(ke)以(yi)照亮(liang)房間，這(zhe)在(zai)以(yi)前是(shi)不可(ke)想象的(de)，但是(shi)新的(de)技術(shu)進步已(yi)經為(wei) LED 照明(ming)的(de)新時代創造了(le)條件。尤其(qi)是(shi)，PhilipsLumileds Luxeon LED 在(zai) 1000mA 時可(ke)以(yi)提供(gong)超過(guo) 100 流(liu)明(ming)的(de)光。我配備了(le)一個(ge) LumiLED 陣(zhen)列，使用(yong) LTC3475 （16 引(yin)線 TSSOP 耐熱增(zeng)強(qiang)型封裝） 雙路(lu) 1.5A 恒(heng)定(ding)電(dian)(dian)(dian)(dian)(dian)流(liu) LED 驅(qu)動(dong)器(qi) DC923A 演(yan)(yan)示板。它設(she)計成用(yong)一個(ge)寬范圍輸入電(dian)(dian)(dian)(dian)(dian)壓 （4V 至 30V） 驅(qu)動(dong)兩(liang)個(ge)信道，每個(ge)信道 1.5A.12V 電(dian)(dian)(dian)(dian)(dian)池直接(jie)連接(jie)到(dao)(dao)演(yan)(yan)示板的(de)輸入，為(wei)每個(ge)通(tong)道 3 個(ge)串聯的(de) LED 燈(deng)供(gong)電(dian)(dian)(dian)(dian)(dian)，當兩(liang)個(ge)通(tong)道都接(jie)通(tong)時，總共有 6 個(ge) LED.這(zhe)些(xie) LED 出奇地(di)亮(liang)，用(yong)一塊柔光布遮上(shang)時，足夠照亮(liang)我們(men)整個(ge)營地(di)。晚(wan)上(shang)的(de)放電(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)流(liu)全部來自電(dian)(dian)(dian)(dian)(dian)池，因為(wei)太陽能電(dian)(dian)(dian)(dian)(dian)池板夜間提供(gong)零電(dian)(dian)(dian)(dian)(dian)力(li)。以(yi) 2A 的(de)總放電(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)流(liu)，可(ke)以(yi)整晚(wan)為(wei)這(zhe)些(xie)燈(deng)供(gong)電(dian)(dian)(dian)(dian)(dian)。到(dao)(dao)接(jie)近中午(wu)或偏下午(wu)時，電(dian)(dian)(dian)(dian)(dian)池再次充滿電(dian)(dian)(dian)(dian)(dian)，為(wei)給噴(pen)霧系統供(gong)電(dian)(dian)(dian)(dian)(dian)做(zuo)好了(le)準備，在(zai)早午(wu)餐(can)后，噴(pen)霧系統就(jiu)可(ke)以(yi)讓我們(men)感(gan)到(dao)(dao)涼爽(shuang)了(le)。