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)(wo)(wo)有 3 周時間完成設(she)計。我(wo)(wo)(wo)(wo)向朋友(you) Simon 請求幫助，Simon 以前用凌力爾特公(gong)司的(de)(de) IC 搞過太(tai)陽(yang)(yang)能(neng)(neng)供電(dian)設(she)計。除(chu)了一臺(tai)顯示工(gong)作原(yuan)理(li)的(de)(de)樣(yang)機，Simon 還給了我(wo)(wo)(wo)(wo)一份原(yuan)理(li)圖，這(zhe)(zhe)臺(tai)樣(yang)機從未連(lian)上太(tai)陽(yang)(yang)能(neng)(neng)電(dian)池板(ban)測(ce)試(shi)過，但在實驗室做過仿(fang)真(zhen)。我(wo)(wo)(wo)(wo)很興奮，有興趣(qu)用真(zhen)實的(de)(de)太(tai)陽(yang)(yang)能(neng)(neng)電(dian)池板(ban)測(ce)試(shi)這(zhe)(zhe)個設(she)計，我(wo)(wo)(wo)(wo)們準備(bei)對樣(yang)機進行(xing)像樣(yang)的(de)(de)測(ce)試(shi)。

　　一位朋友借給我兩塊(kuai) BP 太(tai)(tai)陽能(neng)(neng)電(dian)(dian)(dian)(dian)池(chi)(chi)板(ban)(ban) （BP380U）。在大(da)(da)約 20V 最高輸出電(dian)(dian)(dian)(dian)壓和 4A 最大(da)(da)輸出電(dian)(dian)(dian)(dian)流(liu)時(shi)(shi)，每塊(kuai)電(dian)(dian)(dian)(dian)池(chi)(chi)板(ban)(ban)的(de)峰值功(gong)率都是 80W （實際規格為，在 80W 最大(da)(da)功(gong)率時(shi)(shi)，電(dian)(dian)(dian)(dian)壓為 17.6V，電(dian)(dian)(dian)(dian)流(liu)為 4.55A）。把(ba)這兩塊(kuai)太(tai)(tai)陽能(neng)(neng)電(dian)(dian)(dian)(dian)池(chi)(chi)板(ban)(ban)合起來(lai)，我希望在太(tai)(tai)陽光直接直射在電(dian)(dian)(dian)(dian)池(chi)(chi)板(ban)(ban)上時(shi)(shi)，在峰值條件(jian)下(xia)能(neng)(neng)有 8A 的(de)總電(dian)(dian)(dian)(dian)流(liu)。太(tai)(tai)陽能(neng)(neng)電(dian)(dian)(dian)(dian)池(chi)(chi)板(ban)(ban)連接到 Simon 的(de)樣機(ji)上沒有幾分鐘，系(xi)統(tong)就(jiu)充分運(yun)轉了 （圖 1 和圖 2）。通過對樣機(ji)的(de)初步(bu)測試，查明了幾個(ge)故障，后來(lai)這給我們(men)節省了大(da)(da)量時(shi)(shi)間。

　　圖(tu) 1：測試 BP 太陽能電(dian)池(chi)板， BP380U （0 至 20V 輸(shu)出，4A 峰值功率 80W）

　　圖 2：最初的太陽能充(chong)電(dian)電(dian)路樣(yang)機，采用 12V 海上(shang)用深(shen)周期電(dian)池 。

　　樣機運行良好，因(yin)此我購買了(le)幾塊凌力(li)爾特(te)公司的(de)(de)(de)演(yan)示(shi)板，并稍(shao)作修改(gai)以使(shi)其更(geng)適(shi)合(he)重新(xin)設計(ji)過的(de)(de)(de)系統規(gui)格(ge)要求。我保持樣機作為備份和參考(kao)，同時我設計(ji)了(le)一個新(xin)系統。我們解決(jue)了(le)一些(xie)故(gu)障后，通過這(zhe)些(xie)修改(gai)改(gai)善了(le)原來的(de)(de)(de)樣機。總之，架(jia)構設計(ji)仍(reng)然是相同的(de)(de)(de)：用 0 至(zhi) 20V 的(de)(de)(de)太陽能電(dian)池板，以 4A 的(de)(de)(de)恒定(ding)電(dian)流給一個 12V 的(de)(de)(de)電(dian)池充電(dian),

   太陽能電池(chi)充(chong)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(tu) 3：系統設計方(fang)框圖(tu)

　　圖 4：最終的太陽能充電器電路

　　視太陽的(de)位(wei)置不同而(er)不同，太陽能電(dian)池板(ban)(ban)最初的(de)輸(shu)(shu)出(chu)電(dian)壓在 0V 到(dao) 20V 之間(jian)變化(hua)，那么就用一個能接受這么寬(kuan)輸(shu)(shu)出(chu)范圍(wei)的(de)穩壓器，并保持吸取低的(de)電(dian)流 （每(mei)個電(dian)池板(ban)(ban)上的(de)輸(shu)(shu)入(ru)電(dian)流最大值(zhi)都(dou)是 4A），同時調節一個固定的(de)輸(shu)(shu)出(chu)電(dian)壓。這是在 DC1198A-B 演示板(ban)(ban)上用凌力(li)爾特公(gong)司(si)的(de)微型模塊 （μModule） DC/DC 降壓-升(sheng)壓型開關穩壓器 LTM4607 實現的(de)。

　　LTM4607 是(shi)一個(ge)小型 LGA 封(feng)裝(zhuang) （15mm x 15mm x 2.8mm） 的(de)(de)(de)芯片，其(qi)中(zhong)包括一個(ge)復雜的(de)(de)(de)降壓(ya)(ya)-升(sheng)(sheng)壓(ya)(ya)型 DC/DC 開(kai)關(guan)穩壓(ya)(ya)器(qi)所需的(de)(de)(de)所有支持控(kong)制組件。復雜的(de)(de)(de)開(kai)關(guan)控(kong)制電(dian)(dian)(dian)路和(he) FET 內置到微型模(mo)(mo)塊穩壓(ya)(ya)器(qi)中(zhong)，從而(er)使該器(qi)件非常容易使用。結果是(shi)僅需一個(ge)微型模(mo)(mo)塊穩壓(ya)(ya)器(qi)、電(dian)(dian)(dian)感器(qi)以及幾個(ge)電(dian)(dian)(dian)容器(qi)和(he)電(dian)(dian)(dian)阻器(qi)就完(wan)成(cheng)簡潔規則的(de)(de)(de)布(bu)局(ju)。4.5V 至(zhi) 36V 的(de)(de)(de)寬輸(shu)(shu)入電(dian)(dian)(dian)壓(ya)(ya)范圍至(zhi)固(gu)定 20V 輸(shu)(shu)出(chu)(chu) （范圍為 0.8V 至(zhi) 24V） 對(dui)于太(tai)陽能電(dian)(dian)(dian)池板的(de)(de)(de)特性(xing) （0 至(zhi) 20V 輸(shu)(shu)出(chu)(chu)） 正合適，而(er)且該器(qi)件能加載(zai)高(gao)達 5A 的(de)(de)(de)升(sheng)(sheng)壓(ya)(ya)模(mo)(mo)式(shi)(shi)和(he) 10A 的(de)(de)(de)降壓(ya)(ya)模(mo)(mo)式(shi)(shi)。在太(tai)陽能電(dian)(dian)(dian)池板峰值功(gong)率時，20V 輸(shu)(shu)入至(zhi) 20V/2.5A 輸(shu)(shu)出(chu)(chu)的(de)(de)(de)效(xiao)率是(shi) 91%，而(er)且積極利(li)用了(le)降壓(ya)(ya)-升(sheng)(sheng)壓(ya)(ya)型寬范圍輸(shu)(shu)入的(de)(de)(de)好處。就這個(ge)系(xi)(xi)統設計的(de)(de)(de)目的(de)(de)(de)而(er)言(yan)，輸(shu)(shu)出(chu)(chu)調(diao)節(jie)到 20V，用這個(ge)輸(shu)(shu)出(chu)(chu)給 LTC1435/LT1620 高(gao)效(xiao)率、低壓(ya)(ya)差電(dian)(dian)(dian)池充電(dian)(dian)(dian)器(qi)系(xi)(xi)統供(gong)電(dian)(dian)(dian)。

　　在(zai) 14V 穩定(ding)電(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)時，LTC1435/LT1620 演(yan)(yan)示板 （DC133A） 將(jiang)充(chong)電(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)流(liu)控制到穩定(ding)的(de)(de)(de) 4A.該(gai)演(yan)(yan)示板與 LT1620 數據表(biao)第一頁上的(de)(de)(de)應用電(dian)(dian)(dian)(dian)(dian)路類(lei)似(si)，我(wo)將(jiang) FB 電(dian)(dian)(dian)(dian)(dian)阻器(qi) （110k） 換成一個(ge)(ge)可變電(dian)(dian)(dian)(dian)(dian)位器(qi)，以實現輸出電(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)調節，并將(jiang)電(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)浮置(zhi)電(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)設置(zhi)到 14V.該(gai)演(yan)(yan)示板設計利用 LT1620 軌至(zhi)軌電(dian)(dian)(dian)(dian)(dian)流(liu)檢測放(fang)大(da)器(qi)，結合 LTC1435 開關穩壓(ya)(ya)(ya)器(qi)電(dian)(dian)(dian)(dian)(dian)路的(de)(de)(de)高效率和低(di)壓(ya)(ya)(ya)差(cha)能力，形成了一個(ge)(ge)效率超過 95% 的(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)充(chong)電(dian)(dian)(dian)(dian)(dian)器(qi)，從而(er)(er)在(zai) 4A 充(chong)電(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)流(liu)時僅(jin)需要(yao) 0.5V 輸入(ru)至(zhi)輸出電(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)差(cha)。一個(ge)(ge)到地的(de)(de)(de)編程電(dian)(dian)(dian)(dian)(dian)流(liu)設置(zhi)電(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)充(chong)電(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)流(liu) （4A），該(gai)電(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)充(chong)電(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)流(liu)一直(zhi)(zhi)是(shi)穩定(ding)的(de)(de)(de)，直(zhi)(zhi)到電(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)電(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)達(da)到預設的(de)(de)(de)浮置(zhi)電(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya) （在(zai)本(ben)文情況下為(wei) 14V） 為(wei)止。隨著(zhu)電(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)達(da)到其滿充(chong)電(dian)(dian)(dian)(dian)(dian)狀(zhuang)態，電(dian)(dian)(dian)(dian)(dian)路的(de)(de)(de)編程將(jiang)自動轉入(ru)涓流(liu)充(chong)電(dian)(dian)(dian)(dian)(dian)狀(zhuang)態，并就電(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)的(de)(de)(de)輸出電(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)而(er)(er)言緩慢降低(di)充(chong)電(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)流(liu)。這減(jian)輕(qing)了由于恒定(ding)過沖電(dian)(dian)(dian)(dian)(dian)給電(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)造成的(de)(de)(de)壓(ya)(ya)(ya)力。

　　一(yi)個(ge)(ge)理想(xiang)二極(ji)管(guan)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)(lu)設計與 DC133A 充(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)系(xi)統的輸出串聯，利用(yong) LTC4414 實現電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)(lu)保護(hu)，并允(yun)許在(zai)充(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)(lu)以(yi)(yi)最小損耗運(yun)行的同(tong)(tong)時(shi)使(shi)(shi)(shi)用(yong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)。這種自動電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)源通路(lu)(lu)(lu) （PowerPath？） 控(kong)制(zhi)使(shi)(shi)(shi)外(wai)部設備(bei)能(neng)(neng)(neng)夠自由地用(yong)太陽(yang)能(neng)(neng)(neng)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)板(ban)或電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)供(gong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)。當太陽(yang)能(neng)(neng)(neng)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)板(ban)功率(lv)不足時(shi)，電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)(lu)自動轉為(wei)從電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)吸取功率(lv)。該電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)(lu)設計與 LTC4414 數據表第九頁上的圖(tu) 2 類似。LTC4414 （8 引線 MSOP 封裝） 控(kong)制(zhi)一(yi)個(ge)(ge)外(wai)部 P 溝道 MOSFET，以(yi)(yi)產(chan)生接(jie)(jie)近理想(xiang)的二極(ji)管(guan)功能(neng)(neng)(neng)，用(yong)于電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)源切換(huan)。這允(yun)許多(duo)個(ge)(ge)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)源高(gao)效率(lv)進(jin)行“或” 操作；在(zai)本文情況下(xia)，電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)源是太陽(yang)能(neng)(neng)(neng)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)板(ban)和(he)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)。當連(lian)接(jie)(jie)一(yi)個(ge)(ge)外(wai)部設備(bei)時(shi)，電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)和(he)充(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)系(xi)統接(jie)(jie)受負載狀(zhuang)態(tai)。在(zai)無負載時(shi)，將對電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)充(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)。因此該設計允(yun)許一(yi)起使(shi)(shi)(shi)用(yong)太陽(yang)能(neng)(neng)(neng)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)板(ban)和(he)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)供(gong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)，同(tong)(tong)時(shi)運(yun)行電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)充(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)過(guo)程。這一(yi)部分沒有演示板(ban)可用(yong)，因此我按照定制(zhi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)(lu)板(ban)上的應用(yong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)(lu)進(jin)行設計。

　　電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)檢(jian)測(ce)系統與電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池串聯(lian)(lian)，利用(yong)并聯(lian)(lian)檢(jian)測(ce)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)阻器(qi)測(ce)量(liang)(liang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池的輸(shu)入(ru)充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)和(he)(he)輸(shu)出放(fang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)，而無需斷開電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路。圖(tu) 3 的方框圖(tu)僅說明(ming)了(le)輸(shu)入(ru)充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)。LTC6103 （采用(yong) 8 引(yin)線(xian) MSOP 封裝(zhuang)，在(zai) 4V 至(zhi) 60V 范圍內工作(zuo)） 是一(yi)(yi)個(ge)雙路獨立電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)檢(jian)測(ce)放(fang)大(da)器(qi)，可通過外(wai)部檢(jian)測(ce)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)阻器(qi)監(jian)視電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)。該(gai)器(qi)件以(yi)(yi) mV 為(wei)單位測(ce)量(liang)(liang)和(he)(he)提供電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)和(he)(he)放(fang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)的電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)比率輸(shu)出。在(zai)本文情(qing)況下，它幫助指示電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池充(chong)(chong)和(he)(he)放(fang)了(le)多少電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)量(liang)(liang)。這是一(yi)(yi)種以(yi)(yi)低功率損耗讀取電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)的方法，這對(dui)保持一(yi)(yi)個(ge)高能效系統至(zhi)關重要。我略微調節了(le) LTC6103 （DC1116A） 演示板以(yi)(yi)實現(xian)這一(yi)(yi)點(dian)。引(yin)腳(jiao) 8 和(he)(he) 7 分別與進入(ru)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池的電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)通路 +IN_A 和(he)(he) -IN_A 串聯(lian)(lian)。這將提供進入(ru)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池的充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)。引(yin)腳(jiao) 6 和(he)(he) 5 相互掉換(huan)后反著(zhu)連接(jie)，以(yi)(yi)測(ce)量(liang)(liang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池放(fang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)通路，+IN_B （引(yin)腳(jiao) 5） 連接(jie)到 -IN_A （引(yin)腳(jiao) 7），-IN_B （引(yin)腳(jiao) 6） 連接(jie)到 +IN_A （引(yin)腳(jiao) 8）。電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)阻器(qi)的值以(yi)(yi) 10 為(wei)倍數改變(bian)和(he)(he)調節，以(yi)(yi)便在(zai) 0.1Ω 并聯(lian)(lian)檢(jian)測(ce)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)阻器(qi)與電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路串聯(lian)(lian)時(shi)，輸(shu)出以(yi)(yi) 100mV/A 變(bian)化。圖(tu) 5 中的萬用(yong)表顯示整個(ge)系統的結果。太陽能電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池板輸(shu)出電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓是 17.11V，電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓為(wei) 12.95V，充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(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 和微控制器讀數

　　我(wo)決定(ding)，每(mei)次檢(jian)查電(dian)(dian)路(lu)是否(fou)正(zheng)常運行(xing)時不使用電(dian)(dian)壓(ya)表(biao)，因為電(dian)(dian)壓(ya)表(biao)在沙漠中難(nan)以攜帶。為了避免(mian)攜帶多(duo)個(ge)萬用表(biao)，我(wo)用一個(ge)微控制器(qi)和 ADC 來讀(du)取(qu)系統的電(dian)(dian)壓(ya)值，并在一般(ban)的 LCD 顯示屏(ping)上顯示信息(xi)。這種方法可就(jiu)電(dian)(dian)路(lu)性能(neng)提供實時數據(ju)，而無需連接幾個(ge)萬用表(biao)。

　　我(wo)(wo)使用(yong) DC590B 演示(shi)(shi)板和(he) LTC2418 8信道 / 16 信道 24 位 ADC 演示(shi)(shi)板 DC571A.我(wo)(wo)的(de)(de)(de)(de)同事(shi) Mark Thoren 給了我(wo)(wo) PIC 微(wei)控(kong)制器的(de)(de)(de)(de)嵌入式源代(dai)碼樣(yang)本，我(wo)(wo)微(wei)調了這個(ge)源代(dai)碼樣(yang)本，以(yi)跨 LTC2418 上 ADC 的(de)(de)(de)(de)不同通道對電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)采樣(yang)，并以(yi)可接受(shou)的(de)(de)(de)(de)分辨(bian)率、準(zhun)(zhun)確地讀出(chu) mV 范(fan)圍(wei)的(de)(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)值。既然(ran)基準(zhun)(zhun)電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)的(de)(de)(de)(de)最大范(fan)圍(wei)是 2.5V，那么我(wo)(wo)用(yong)一(yi)(yi)種(zhong)電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)分壓(ya)(ya)器方法來按比例將電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)降低到(dao) mV 范(fan)圍(wei)，以(yi)在(zai)(zai) ADC 上實現(xian)正確的(de)(de)(de)(de)測量。通道連接到(dao)單個(ge)有關的(de)(de)(de)(de)輸入和(he)輸出(chu)電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)上，包括電(dian)(dian)(dian)(dian)(dian)(dian)流檢測電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)。這么做非常成功，無需多個(ge)萬用(yong)表(biao)。圖(tu) 6 是一(yi)(yi)個(ge)有關這個(ge) LCD 顯(xian)示(shi)(shi)屏的(de)(de)(de)(de)全功能系統的(de)(de)(de)(de)例子(zi)。我(wo)(wo)在(zai)(zai) LCD 上得到(dao)的(de)(de)(de)(de)最后(hou)的(de)(de)(de)(de)顯(xian)示(shi)(shi)提供了有關以(yi)下電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)的(de)(de)(de)(de)信息：變化的(de)(de)(de)(de)太(tai)陽能電(dian)(dian)(dian)(dian)(dian)(dian)源電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya) Vs、充電(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)路電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya) Vc、電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya) Vb、以(yi)及電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)上的(de)(de)(de)(de)輸入充電(dian)(dian)(dian)(dian)(dian)(dian)/放電(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)流 C 和(he) D.在(zai)(zai)本文(wen)情況下，是“C”，它在(zai)(zai)充電(dian)(dian)(dian)(dian)(dian)(dian)。放電(dian)(dian)(dian)(dian)(dian)(dian)時，程(cheng)序將改變到(dao)“D”。

　　圖 6:LCD 讀(du)(du)數：Vs （太陽(yang)能電池板電壓(ya)(ya)）；Vc （充電電路電壓(ya)(ya)）；Vb （電池電壓(ya)(ya)）；C = 充電電流 （4.3A），用(yong)DC590B PIC 微控(kong)(kong)制器控(kong)(kong)制；用(yong) LTC2418 演示(shi)板 DC571 ADC 讀(du)(du)取(qu)電壓(ya)(ya)，該演示(shi)板由 LTM4601演示(shi)板 DC1041A 微型模塊(kuai)降壓(ya)(ya)型穩壓(ya)(ya)器供(gong)電。

　　注(zhu)意，DC590B 演示板不是(shi)靠 12V 軌(gui)(gui)供電，而是(shi)靠 5V 軌(gui)(gui)供電。需(xu)要一個(ge)降(jiang)(jiang)壓(ya)(ya)型穩壓(ya)(ya)器將電壓(ya)(ya)從電池(chi)的 12V 降(jiang)(jiang)低到 5V.這個(ge)降(jiang)(jiang)壓(ya)(ya)型穩壓(ya)(ya)器將必須是(shi)高(gao)效率的，因(yin)為電源將來自太陽(yang)能電池(chi)板和電池(chi)，我不想(xiang)因(yin)運行 LCD 顯示屏和微控制(zhi)器而耗費大量功率。我使用(yong) LTM4601 微型模(mo)塊 DC/DC 開關(guan)穩壓(ya)(ya)器演示板 DC1041A.

　　LTM4601 是一(yi)(yi)(yi)個(ge) LGA 封裝的 15mm x 15mm x 2.8mm 微型模塊(kuai) DC/DC 開關(guan)穩壓(ya)器(qi)(qi)，在(zai)(zai) 12A 最(zui)大負(fu)載電(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)時，輸入為(wei)(wei) 4.5V 至 20V，輸出(chu)為(wei)(wei) 0.6V 至 5V.LTM4601 的設計使得(de)非(fei)常容(rong)(rong)易(yi)從 12V 電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)提供一(yi)(yi)(yi)個(ge)穩定的 5V 輸出(chu)。該微型模塊(kuai)包括所有(you)控制(zhi)支(zhi)持組件，如(ru)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)阻器(qi)(qi)、電(dian)(dian)(dian)(dian)(dian)(dian)(dian)容(rong)(rong)器(qi)(qi)、MOSFET 和(he)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)感(gan)器(qi)(qi)。在(zai)(zai)這個(ge)系統中，效(xiao)率大約為(wei)(wei) 90%，使用最(zui)小的電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)，極大地延長(chang)了電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)壽命。更(geng)容(rong)(rong)易(yi)的是，輸出(chu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)用一(yi)(yi)(yi)個(ge)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)阻器(qi)(qi)設置，如(ru)果(guo)我需(xu)要一(yi)(yi)(yi)個(ge)不同的電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)軌 （例如(ru) 3.3V、2.5V、1.8V、1.5V 和(he) 1.2V），那么在(zai)(zai)演示板上用一(yi)(yi)(yi)條跨接(jie)線可(ke)以非(fei)常容(rong)(rong)易(yi)地改變這個(ge)輸出(chu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)。

　　總(zong)之，兩塊 BP 太(tai)陽(yang)能電(dian)(dian)池(chi)板，每塊在(zai) 4A 電(dian)(dian)流時都有 0 至 20V 的(de)(de)(de)輸(shu)(shu)出(chu)，這(zhe)兩塊太(tai)陽(yang)能電(dian)(dian)池(chi)板由 20V 輸(shu)(shu)出(chu)的(de)(de)(de) LTM4607 降壓(ya)(ya)/升壓(ya)(ya)型(xing)微型(xing)模(mo)塊開關(guan)穩壓(ya)(ya)器(qi)調節，然后再到 14V 輸(shu)(shu)入(ru)的(de)(de)(de) LTC1435/LT1620 電(dian)(dian)池(chi)充(chong)電(dian)(dian)器(qi)，通(tong)過一個(ge)理想(xiang)二極管 MOSFET 控制器(qi) LTC4414、一個(ge)串聯的(de)(de)(de)電(dian)(dian)流檢測放大器(qi) LTC6103，最終進(jin)入(ru)電(dian)(dian)池(chi)；以穩定的(de)(de)(de) 4A 電(dian)(dian)流充(chong)電(dian)(dian)。在(zai)這(zhe)個(ge)設(she)計中，由 LTC2418 在(zai)不同(tong)的(de)(de)(de)級獲取(qu) ADC 讀數(shu)，并(bing)將讀數(shu)送至由 LTM4601 微型(xing)模(mo)塊開關(guan)穩壓(ya)(ya)器(qi)供電(dian)(dian)的(de)(de)(de) DC590B 演(yan)示(shi)板微控制器(qi)，以在(zai) LCD 上(shang)顯示(shi)結果。圖 7 顯示(shi)正在(zai)運行的(de)(de)(de)整個(ge)系統(tong)。

　　圖(tu) 7：運行(xing)中的(de)整個(ge)系統設(she)計

　　噴霧系統的機械設計

　　有了(le)一個正(zheng)常工作的(de)太陽能(neng)充電(dian)(dian)器和穩定(ding)的(de) 12V 輸出(chu)，我就(jiu)準備好著手組裝噴霧系統(tong)了(le)。去一趟五金店(dian)就(jiu)得到了(le)我需要的(de)材料(liao)：艙底污水(shui)(shui)泵(beng)、水(shui)(shui)龍帶(dai)(dai)連接器、水(shui)(shui)龍帶(dai)(dai)夾(jia)具(ju)、轉接器和噴霧系統(tong)。水(shui)(shui)龍帶(dai)(dai)長約 15 英尺，擰在轉接器螺釘上，用水(shui)(shui)龍帶(dai)(dai)夾(jia)具(ju)固(gu)定(ding)到水(shui)(shui)泵(beng)上，噴霧系統(tong)固(gu)定(ding)在末端，有 5 個噴霧嘴。底艙污水(shui)(shui)泵(beng)靠最大值為 12V 的(de)電(dian)(dian)壓運行，水(shui)(shui)壓可以(yi)通過降低電(dian)(dian)壓來控制。

　　為了(le)(le)實現靈活性，我(wo)安(an)裝了(le)(le)一(yi)個穩壓(ya)(ya)器，該(gai)穩壓(ya)(ya)器可以接受(shou) 12V 輸(shu)(shu)(shu)入，并將輸(shu)(shu)(shu)入轉換成可變的 12V 輸(shu)(shu)(shu)出(chu)。這要求 LTM4607 設計有降壓(ya)(ya)/升壓(ya)(ya)特性。該(gai)器件使用一(yi)個反饋電(dian)(dian)(dian)阻器控制輸(shu)(shu)(shu)出(chu)電(dian)(dian)(dian)壓(ya)(ya)。一(yi)個 50k 的可變旋(xuan)鈕電(dian)(dian)(dian)位器取代了(le)(le)電(dian)(dian)(dian)阻器，從而非常(chang)容易控制 0.8V 至 12V 的輸(shu)(shu)(shu)出(chu)。還串(chuan)聯(lian)了(le)(le)一(yi)個 5.62k 的電(dian)(dian)(dian)阻器，以限制輸(shu)(shu)(shu)出(chu)電(dian)(dian)(dian)壓(ya)(ya)，保(bao)持(chi)輸(shu)(shu)(shu)出(chu)低于 15V.該(gai)設計通過旋(xuan)轉一(yi)個旋(xuan)鈕實現了(le)(le)水壓(ya)(ya)控制。

　　然后，我就可(ke)以(yi)測試(shi)我的(de)全功能(neng)(neng)噴(pen)霧(wu)系(xi)統(tong)了(le)。結果(guo)，水泵(beng)導(dao)致最大(da)約 6A 的(de)電(dian)(dian)(dian)(dian)池(chi)(chi)放(fang)(fang)電(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)流(liu)，這(zhe)意味著，在峰值(zhi)輸出時，水泵(beng)約從每(mei)塊太陽(yang)能(neng)(neng)電(dian)(dian)(dian)(dian)池(chi)(chi)板獲得 4A 電(dian)(dian)(dian)(dian)流(liu)。控制水泵(beng)速度和壓(ya)力的(de)好處是，我可(ke)以(yi)將(jiang)壓(ya)力降到足夠低(di)，以(yi)降低(di)電(dian)(dian)(dian)(dian)池(chi)(chi)的(de)放(fang)(fang)電(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)流(liu)，并全部靠太陽(yang)能(neng)(neng)電(dian)(dian)(dian)(dian)池(chi)(chi)板運(yun)行水泵(beng)，以(yi)節省電(dian)(dian)(dian)(dian)池(chi)(chi)電(dian)(dian)(dian)(dian)量，這(zhe)樣做非常有效。通過這(zhe)種方法，我們能(neng)(neng)夠在營地全天(tian)運(yun)行噴(pen)霧(wu)系(xi)統(tong)，而(er)不必擔(dan)心電(dian)(dian)(dian)(dian)池(chi)(chi)放(fang)(fang)電(dian)(dian)(dian)(dian)，耽誤(wu)夜間用于 LED 照(zhao)明系(xi)統(tong)。

　　LED 照明

　　隨著電(dian)源的(de)完成(cheng)，我(wo)就可(ke)(ke)(ke)以(yi)(yi)增(zeng)加(jia)電(dian)路，在(zai)(zai)晚上高效率地提供(gong)照(zhao)明了(le)。LED 足(zu)夠亮(liang)，可(ke)(ke)(ke)以(yi)(yi)照(zhao)亮(liang)房間，這(zhe)在(zai)(zai)以(yi)(yi)前是(shi)不可(ke)(ke)(ke)想(xiang)象的(de)，但(dan)是(shi)新(xin)的(de)技(ji)術進步已經(jing)為(wei) LED 照(zhao)明的(de)新(xin)時(shi)代(dai)創造了(le)條件(jian)。尤其是(shi)，PhilipsLumileds Luxeon LED 在(zai)(zai) 1000mA 時(shi)可(ke)(ke)(ke)以(yi)(yi)提供(gong)超過 100 流(liu)(liu)明的(de)光(guang)。我(wo)配備了(le)一(yi)個(ge) LumiLED 陣列，使用(yong) LTC3475 （16 引線(xian) TSSOP 耐熱增(zeng)強型封裝） 雙路 1.5A 恒定(ding)電(dian)流(liu)(liu) LED 驅(qu)動(dong)器 DC923A 演(yan)(yan)示板(ban)。它設計(ji)成(cheng)用(yong)一(yi)個(ge)寬范圍輸入(ru)電(dian)壓 （4V 至 30V） 驅(qu)動(dong)兩(liang)個(ge)信道(dao)(dao)(dao)，每個(ge)信道(dao)(dao)(dao) 1.5A.12V 電(dian)池直接(jie)連接(jie)到(dao)演(yan)(yan)示板(ban)的(de)輸入(ru)，為(wei)每個(ge)通(tong)道(dao)(dao)(dao) 3 個(ge)串聯的(de) LED 燈供(gong)電(dian)，當(dang)兩(liang)個(ge)通(tong)道(dao)(dao)(dao)都接(jie)通(tong)時(shi)，總共有(you) 6 個(ge) LED.這(zhe)些 LED 出奇地亮(liang)，用(yong)一(yi)塊(kuai)柔光(guang)布遮上時(shi)，足(zu)夠照(zhao)亮(liang)我(wo)們整(zheng)個(ge)營地。晚上的(de)放(fang)電(dian)電(dian)流(liu)(liu)全部來自電(dian)池，因為(wei)太陽能電(dian)池板(ban)夜(ye)間提供(gong)零電(dian)力。以(yi)(yi) 2A 的(de)總放(fang)電(dian)電(dian)流(liu)(liu)，可(ke)(ke)(ke)以(yi)(yi)整(zheng)晚為(wei)這(zhe)些燈供(gong)電(dian)。到(dao)接(jie)近中午或偏下午時(shi)，電(dian)池再次充滿電(dian)，為(wei)給噴霧(wu)(wu)系統供(gong)電(dian)做好了(le)準備，在(zai)(zai)早午餐后，噴霧(wu)(wu)系統就可(ke)(ke)(ke)以(yi)(yi)讓(rang)我(wo)們感到(dao)涼(liang)爽(shuang)了(le)。