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。

　　我有(you)(you) 3 周時間完成設計。我向朋友 Simon 請求幫助，Simon 以前用凌力爾特公司(si)的(de) IC 搞過(guo)太(tai)陽能供電設計。除(chu)了(le)一臺顯(xian)示工(gong)作原(yuan)理的(de)樣機(ji)(ji)，Simon 還給了(le)我一份原(yuan)理圖，這(zhe)臺樣機(ji)(ji)從未連(lian)上(shang)太(tai)陽能電池(chi)(chi)板測(ce)(ce)試過(guo)，但在實驗室(shi)做過(guo)仿真。我很(hen)興(xing)奮，有(you)(you)興(xing)趣用真實的(de)太(tai)陽能電池(chi)(chi)板測(ce)(ce)試這(zhe)個設計，我們(men)準備對樣機(ji)(ji)進行像(xiang)樣的(de)測(ce)(ce)試。

　　一位朋友借給(gei)我(wo)(wo)兩(liang)塊 BP 太陽(yang)能(neng)電(dian)(dian)池板(ban) （BP380U）。在(zai)(zai)大(da)(da)約(yue) 20V 最高輸出(chu)電(dian)(dian)壓和 4A 最大(da)(da)輸出(chu)電(dian)(dian)流時(shi)(shi)，每塊電(dian)(dian)池板(ban)的峰值(zhi)功(gong)(gong)率都是 80W （實際規格為(wei)，在(zai)(zai) 80W 最大(da)(da)功(gong)(gong)率時(shi)(shi)，電(dian)(dian)壓為(wei) 17.6V，電(dian)(dian)流為(wei) 4.55A）。把這(zhe)兩(liang)塊太陽(yang)能(neng)電(dian)(dian)池板(ban)合起來(lai)，我(wo)(wo)希望在(zai)(zai)太陽(yang)光直接直射在(zai)(zai)電(dian)(dian)池板(ban)上時(shi)(shi)，在(zai)(zai)峰值(zhi)條件下能(neng)有 8A 的總(zong)電(dian)(dian)流。太陽(yang)能(neng)電(dian)(dian)池板(ban)連接到 Simon 的樣(yang)機上沒有幾(ji)分(fen)鐘，系統(tong)就充分(fen)運(yun)轉了(le) （圖 1 和圖 2）。通過對樣(yang)機的初步測試，查明(ming)了(le)幾(ji)個故(gu)障，后(hou)來(lai)這(zhe)給(gei)我(wo)(wo)們節省了(le)大(da)(da)量時(shi)(shi)間。

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

　　圖(tu) 2：最初的太陽能(neng)充(chong)電電路樣機，采用(yong) 12V 海上用(yong)深周期(qi)電池 。

　　樣(yang)(yang)機(ji)運行良好，因此我購買了幾塊凌力(li)爾特公司的演示(shi)板(ban)，并稍作(zuo)修改以(yi)使其更適合重新(xin)(xin)設(she)計過的系統規格要求(qiu)。我保(bao)持樣(yang)(yang)機(ji)作(zuo)為備份和(he)參考，同(tong)時我設(she)計了一個新(xin)(xin)系統。我們解(jie)決了一些故障后，通過這些修改改善了原來的樣(yang)(yang)機(ji)。總之，架(jia)構設(she)計仍然(ran)是相(xiang)同(tong)的：用 0 至 20V 的太陽能電池(chi)板(ban)，以(yi) 4A 的恒定電流(liu)給一個 12V 的電池(chi)充電,

   太陽能電池(chi)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：系統設(she)計方框圖

　　圖 4：最終的太陽能充電器電路

　　視太陽的(de)(de)(de)位置不同而不同，太陽能電(dian)(dian)池板(ban)最初的(de)(de)(de)輸出電(dian)(dian)壓(ya)(ya)(ya)(ya)在 0V 到 20V 之間變化，那么(me)就用一個能接受這么(me)寬(kuan)輸出范圍的(de)(de)(de)穩壓(ya)(ya)(ya)(ya)器，并保持吸(xi)取(qu)低的(de)(de)(de)電(dian)(dian)流 （每個電(dian)(dian)池板(ban)上的(de)(de)(de)輸入電(dian)(dian)流最大值都(dou)是(shi) 4A），同時調節一個固定(ding)的(de)(de)(de)輸出電(dian)(dian)壓(ya)(ya)(ya)(ya)。這是(shi)在 DC1198A-B 演示板(ban)上用凌力爾特(te)公司的(de)(de)(de)微型(xing)模塊 （μModule） DC/DC 降壓(ya)(ya)(ya)(ya)-升壓(ya)(ya)(ya)(ya)型(xing)開關(guan)穩壓(ya)(ya)(ya)(ya)器 LTM4607 實現(xian)的(de)(de)(de)。

　　LTM4607 是一個(ge)小型(xing) LGA 封裝 （15mm x 15mm x 2.8mm） 的(de)芯片，其(qi)中包括一個(ge)復(fu)雜的(de)降壓-升(sheng)壓型(xing) DC/DC 開(kai)(kai)關穩(wen)(wen)壓器(qi)(qi)所需(xu)的(de)所有支持控制組件。復(fu)雜的(de)開(kai)(kai)關控制電(dian)路和(he)(he) FET 內(nei)置到微型(xing)模(mo)塊(kuai)穩(wen)(wen)壓器(qi)(qi)中，從而使該器(qi)(qi)件非常容(rong)易使用。結(jie)果是僅需(xu)一個(ge)微型(xing)模(mo)塊(kuai)穩(wen)(wen)壓器(qi)(qi)、電(dian)感(gan)器(qi)(qi)以及幾個(ge)電(dian)容(rong)器(qi)(qi)和(he)(he)電(dian)阻器(qi)(qi)就(jiu)完成簡潔規則的(de)布局。4.5V 至(zhi) 36V 的(de)寬(kuan)輸(shu)入(ru)電(dian)壓范圍(wei)至(zhi)固定 20V 輸(shu)出(chu) （范圍(wei)為 0.8V 至(zhi) 24V） 對于太陽(yang)能(neng)電(dian)池板的(de)特(te)性 （0 至(zhi) 20V 輸(shu)出(chu)） 正合適，而且該器(qi)(qi)件能(neng)加載高達(da) 5A 的(de)升(sheng)壓模(mo)式和(he)(he) 10A 的(de)降壓模(mo)式。在太陽(yang)能(neng)電(dian)池板峰值功(gong)率(lv)時(shi)，20V 輸(shu)入(ru)至(zhi) 20V/2.5A 輸(shu)出(chu)的(de)效率(lv)是 91%，而且積極利用了降壓-升(sheng)壓型(xing)寬(kuan)范圍(wei)輸(shu)入(ru)的(de)好處(chu)。就(jiu)這個(ge)系(xi)統(tong)設計的(de)目的(de)而言，輸(shu)出(chu)調節到 20V，用這個(ge)輸(shu)出(chu)給 LTC1435/LT1620 高效率(lv)、低壓差電(dian)池充電(dian)器(qi)(qi)系(xi)統(tong)供(gong)電(dian)。

　　在 14V 穩定(ding)電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)時，LTC1435/LT1620 演示板 （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)穩定(ding)的(de) 4A.該演示板與 LT1620 數(shu)據表第一(yi)頁上的(de)應用(yong)電(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)類似(si)，我將 FB 電(dian)(dian)(dian)(dian)(dian)(dian)阻器 （110k） 換成(cheng)一(yi)個可變電(dian)(dian)(dian)(dian)(dian)(dian)位(wei)器，以實現輸出電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)調節，并(bing)將電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)浮置(zhi)(zhi)電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)設(she)置(zhi)(zhi)到(dao) 14V.該演示板設(she)計利用(yong) LT1620 軌至軌電(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)檢測放大器，結合 LTC1435 開關穩壓(ya)(ya)器電(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)的(de)高(gao)效率和(he)低壓(ya)(ya)差(cha)能(neng)力(li)，形成(cheng)了(le)一(yi)個效率超過 95% 的(de)電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)器，從(cong)而在 4A 充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)時僅需要 0.5V 輸入至輸出電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)差(cha)。一(yi)個到(dao)地(di)的(de)編(bian)程(cheng)電(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)設(she)置(zhi)(zhi)電(dian)(dian)(dian)(dian)(dian)(dian)池(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)充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)一(yi)直是穩定(ding)的(de)，直到(dao)電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)達到(dao)預(yu)設(she)的(de)浮置(zhi)(zhi)電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya) （在本文情況(kuang)下(xia)為 14V） 為止。隨著電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)達到(dao)其滿(man)充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)狀態，電(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)的(de)編(bian)程(cheng)將自動(dong)轉入涓(juan)流(liu)(liu)(liu)充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)狀態，并(bing)就電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)的(de)輸出電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)而言(yan)緩慢降低充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)。這(zhe)減輕了(le)由于恒定(ding)過沖電(dian)(dian)(dian)(dian)(dian)(dian)給電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)造成(cheng)的(de)壓(ya)(ya)力(li)。

　　一(yi)(yi)個(ge)(ge)理想二極管電(dian)(dian)路(lu)(lu)設計與 DC133A 充(chong)(chong)電(dian)(dian)系統(tong)的輸出串聯，利(li)用 LTC4414 實(shi)現電(dian)(dian)路(lu)(lu)保(bao)護，并(bing)允(yun)許(xu)在充(chong)(chong)電(dian)(dian)電(dian)(dian)路(lu)(lu)以最小損耗運行(xing)的同時(shi)使用電(dian)(dian)池(chi)。這(zhe)(zhe)種自動(dong)電(dian)(dian)源通(tong)路(lu)(lu) （PowerPath？） 控制(zhi)(zhi)使外部設備(bei)能(neng)(neng)夠自由地用太(tai)陽(yang)能(neng)(neng)電(dian)(dian)池(chi)板(ban)或電(dian)(dian)池(chi)供電(dian)(dian)。當(dang)太(tai)陽(yang)能(neng)(neng)電(dian)(dian)池(chi)板(ban)功率(lv)不(bu)足時(shi)，電(dian)(dian)路(lu)(lu)自動(dong)轉為(wei)從電(dian)(dian)池(chi)吸取功率(lv)。該(gai)電(dian)(dian)路(lu)(lu)設計與 LTC4414 數據表第九頁上的圖 2 類似。LTC4414 （8 引線 MSOP 封裝） 控制(zhi)(zhi)一(yi)(yi)個(ge)(ge)外部 P 溝道(dao) MOSFET，以產生接近理想的二極管功能(neng)(neng)，用于(yu)電(dian)(dian)源切換。這(zhe)(zhe)允(yun)許(xu)多(duo)個(ge)(ge)電(dian)(dian)源高效率(lv)進(jin)行(xing)“或” 操作；在本文(wen)情況(kuang)下，電(dian)(dian)源是太(tai)陽(yang)能(neng)(neng)電(dian)(dian)池(chi)板(ban)和(he)電(dian)(dian)池(chi)。當(dang)連接一(yi)(yi)個(ge)(ge)外部設備(bei)時(shi)，電(dian)(dian)池(chi)和(he)充(chong)(chong)電(dian)(dian)系統(tong)接受(shou)負載狀(zhuang)態。在無(wu)負載時(shi)，將對電(dian)(dian)池(chi)充(chong)(chong)電(dian)(dian)。因此該(gai)設計允(yun)許(xu)一(yi)(yi)起使用太(tai)陽(yang)能(neng)(neng)電(dian)(dian)池(chi)板(ban)和(he)電(dian)(dian)池(chi)供電(dian)(dian)，同時(shi)運行(xing)電(dian)(dian)池(chi)充(chong)(chong)電(dian)(dian)過程。這(zhe)(zhe)一(yi)(yi)部分沒有演示板(ban)可(ke)用，因此我按(an)照定(ding)制(zhi)(zhi)電(dian)(dian)路(lu)(lu)板(ban)上的應用電(dian)(dian)路(lu)(lu)進(jin)行(xing)設計。

　　電(dian)(dian)(dian)(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)(dian)(dian)(dian)池(chi)(chi)串聯(lian)(lian)，利用并(bing)聯(lian)(lian)檢(jian)測(ce)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)阻器(qi)(qi)測(ce)量電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)的(de)(de)(de)輸(shu)(shu)(shu)入(ru)充電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)和(he)輸(shu)(shu)(shu)出放(fang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)，而無需斷(duan)開電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)(lu)。圖(tu)(tu) 3 的(de)(de)(de)方(fang)框(kuang)圖(tu)(tu)僅(jin)說明了輸(shu)(shu)(shu)入(ru)充電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)。LTC6103 （采用 8 引(yin)(yin)線 MSOP 封裝(zhuang)，在 4V 至 60V 范圍內工作） 是(shi)一(yi)(yi)(yi)個(ge)雙路(lu)(lu)(lu)獨立電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)檢(jian)測(ce)放(fang)大器(qi)(qi)，可通(tong)過外部檢(jian)測(ce)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)阻器(qi)(qi)監視電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)。該器(qi)(qi)件以(yi) mV 為單位測(ce)量和(he)提供電(dian)(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)(dian)和(he)放(fang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)的(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)比率輸(shu)(shu)(shu)出。在本文情況下，它幫助指(zhi)示電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)充和(he)放(fang)了多少(shao)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)量。這(zhe)是(shi)一(yi)(yi)(yi)種以(yi)低功率損(sun)耗讀(du)取電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)的(de)(de)(de)方(fang)法(fa)，這(zhe)對(dui)保持(chi)一(yi)(yi)(yi)個(ge)高(gao)能效系統至關重要。我略微(wei)調節(jie)了 LTC6103 （DC1116A） 演示板(ban)以(yi)實現這(zhe)一(yi)(yi)(yi)點。引(yin)(yin)腳(jiao)(jiao)(jiao) 8 和(he) 7 分別(bie)與進入(ru)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)的(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)通(tong)路(lu)(lu)(lu) +IN_A 和(he) -IN_A 串聯(lian)(lian)。這(zhe)將提供進入(ru)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)的(de)(de)(de)充電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)。引(yin)(yin)腳(jiao)(jiao)(jiao) 6 和(he) 5 相互(hu)掉換后反著(zhu)連接，以(yi)測(ce)量電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)放(fang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)通(tong)路(lu)(lu)(lu)，+IN_B （引(yin)(yin)腳(jiao)(jiao)(jiao) 5） 連接到 -IN_A （引(yin)(yin)腳(jiao)(jiao)(jiao) 7），-IN_B （引(yin)(yin)腳(jiao)(jiao)(jiao) 6） 連接到 +IN_A （引(yin)(yin)腳(jiao)(jiao)(jiao) 8）。電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)阻器(qi)(qi)的(de)(de)(de)值以(yi) 10 為倍數改變和(he)調節(jie)，以(yi)便(bian)在 0.1Ω 并(bing)聯(lian)(lian)檢(jian)測(ce)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)阻器(qi)(qi)與電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)(lu)串聯(lian)(lian)時(shi)，輸(shu)(shu)(shu)出以(yi) 100mV/A 變化。圖(tu)(tu) 5 中的(de)(de)(de)萬用表顯示整(zheng)個(ge)系統的(de)(de)(de)結果(guo)。太陽能電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)板(ban)輸(shu)(shu)(shu)出電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)是(shi) 17.11V，電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)電(dian)(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)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)是(shi) 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(shu)

　　我決定(ding)，每次檢查電(dian)路是否正常運行時(shi)(shi)不使用電(dian)壓表(biao)，因為電(dian)壓表(biao)在(zai)沙漠(mo)中難以攜帶(dai)(dai)。為了避免(mian)攜帶(dai)(dai)多(duo)個(ge)萬用表(biao)，我用一個(ge)微控(kong)制(zhi)器和(he) ADC 來讀取系統的(de)電(dian)壓值，并在(zai)一般(ban)的(de) LCD 顯示屏上顯示信息。這種(zhong)方法(fa)可就(jiu)電(dian)路性能提供實時(shi)(shi)數據，而無(wu)需連接幾個(ge)萬用表(biao)。

　　我(wo)(wo)使用 DC590B 演(yan)示(shi)(shi)板和 LTC2418 8信道 / 16 信道 24 位 ADC 演(yan)示(shi)(shi)板 DC571A.我(wo)(wo)的(de)(de)(de)(de)(de)(de)(de)(de)同(tong)事 Mark Thoren 給了我(wo)(wo) PIC 微(wei)控制(zhi)器的(de)(de)(de)(de)(de)(de)(de)(de)嵌入式源代(dai)碼樣本(ben)，我(wo)(wo)微(wei)調了這個源代(dai)碼樣本(ben)，以(yi)(yi)(yi)跨 LTC2418 上(shang)(shang) ADC 的(de)(de)(de)(de)(de)(de)(de)(de)不同(tong)通道對(dui)電(dian)(dian)壓(ya)采樣，并以(yi)(yi)(yi)可(ke)接(jie)受(shou)的(de)(de)(de)(de)(de)(de)(de)(de)分辨(bian)率、準(zhun)確地讀出 mV 范圍(wei)的(de)(de)(de)(de)(de)(de)(de)(de)電(dian)(dian)壓(ya)值。既然基準(zhun)電(dian)(dian)壓(ya)的(de)(de)(de)(de)(de)(de)(de)(de)最大范圍(wei)是 2.5V，那么(me)我(wo)(wo)用一種電(dian)(dian)壓(ya)分壓(ya)器方法來按(an)比例將電(dian)(dian)壓(ya)降低到 mV 范圍(wei)，以(yi)(yi)(yi)在(zai) ADC 上(shang)(shang)實現正確的(de)(de)(de)(de)(de)(de)(de)(de)測(ce)量。通道連接(jie)到單個有關的(de)(de)(de)(de)(de)(de)(de)(de)輸入和輸出電(dian)(dian)壓(ya)上(shang)(shang)，包括電(dian)(dian)流檢測(ce)電(dian)(dian)壓(ya)。這么(me)做(zuo)非常(chang)成功(gong)，無需多個萬用表。圖(tu) 6 是一個有關這個 LCD 顯示(shi)(shi)屏的(de)(de)(de)(de)(de)(de)(de)(de)全功(gong)能(neng)系(xi)統的(de)(de)(de)(de)(de)(de)(de)(de)例子。我(wo)(wo)在(zai) LCD 上(shang)(shang)得到的(de)(de)(de)(de)(de)(de)(de)(de)最后的(de)(de)(de)(de)(de)(de)(de)(de)顯示(shi)(shi)提供了有關以(yi)(yi)(yi)下電(dian)(dian)壓(ya)的(de)(de)(de)(de)(de)(de)(de)(de)信息：變(bian)化(hua)的(de)(de)(de)(de)(de)(de)(de)(de)太陽能(neng)電(dian)(dian)源電(dian)(dian)壓(ya) Vs、充(chong)電(dian)(dian)電(dian)(dian)路(lu)電(dian)(dian)壓(ya) Vc、電(dian)(dian)池電(dian)(dian)壓(ya) Vb、以(yi)(yi)(yi)及電(dian)(dian)池上(shang)(shang)的(de)(de)(de)(de)(de)(de)(de)(de)輸入充(chong)電(dian)(dian)/放電(dian)(dian)電(dian)(dian)流 C 和 D.在(zai)本(ben)文(wen)情況下，是“C”，它(ta)在(zai)充(chong)電(dian)(dian)。放電(dian)(dian)時，程序將改變(bian)到“D”。

　　圖 6:LCD 讀(du)數：Vs （太陽能電(dian)池(chi)板(ban)電(dian)壓(ya)(ya)）；Vc （充電(dian)電(dian)路電(dian)壓(ya)(ya)）；Vb （電(dian)池(chi)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(shi)板(ban) DC571 ADC 讀(du)取電(dian)壓(ya)(ya)，該(gai)演示(shi)板(ban)由 LTM4601演示(shi)板(ban) DC1041A 微型(xing)模塊降(jiang)壓(ya)(ya)型(xing)穩壓(ya)(ya)器供電(dian)。

　　注意，DC590B 演示(shi)板不是靠 12V 軌供(gong)電(dian)(dian)(dian)，而是靠 5V 軌供(gong)電(dian)(dian)(dian)。需要一個降壓(ya)(ya)(ya)型(xing)穩(wen)(wen)壓(ya)(ya)(ya)器將電(dian)(dian)(dian)壓(ya)(ya)(ya)從電(dian)(dian)(dian)池的 12V 降低(di)到 5V.這個降壓(ya)(ya)(ya)型(xing)穩(wen)(wen)壓(ya)(ya)(ya)器將必(bi)須是高效率的，因為電(dian)(dian)(dian)源將來自太陽能電(dian)(dian)(dian)池板和電(dian)(dian)(dian)池，我不想因運行 LCD 顯示(shi)屏和微控(kong)制器而耗費(fei)大量功率。我使用 LTM4601 微型(xing)模(mo)塊 DC/DC 開關(guan)穩(wen)(wen)壓(ya)(ya)(ya)器演示(shi)板 DC1041A.

　　LTM4601 是一(yi)(yi)(yi)個(ge)(ge)(ge) LGA 封裝(zhuang)的(de) 15mm x 15mm x 2.8mm 微型模塊 DC/DC 開(kai)關穩(wen)壓(ya)(ya)器，在 12A 最大(da)負載(zai)電(dian)(dian)流時，輸(shu)(shu)入為 4.5V 至(zhi) 20V，輸(shu)(shu)出(chu)為 0.6V 至(zhi) 5V.LTM4601 的(de)設計使(shi)得非(fei)(fei)常(chang)(chang)容(rong)易(yi)從 12V 電(dian)(dian)池(chi)提(ti)供(gong)一(yi)(yi)(yi)個(ge)(ge)(ge)穩(wen)定的(de) 5V 輸(shu)(shu)出(chu)。該微型模塊包括所有(you)控制支持組(zu)件(jian)，如電(dian)(dian)阻器、電(dian)(dian)容(rong)器、MOSFET 和電(dian)(dian)感器。在這(zhe)個(ge)(ge)(ge)系統中，效率大(da)約為 90%，使(shi)用最小的(de)電(dian)(dian)池(chi)電(dian)(dian)流，極大(da)地(di)延(yan)長了電(dian)(dian)池(chi)壽命(ming)。更容(rong)易(yi)的(de)是，輸(shu)(shu)出(chu)電(dian)(dian)壓(ya)(ya)用一(yi)(yi)(yi)個(ge)(ge)(ge)電(dian)(dian)阻器設置，如果(guo)我需(xu)要一(yi)(yi)(yi)個(ge)(ge)(ge)不同的(de)電(dian)(dian)壓(ya)(ya)軌 （例如 3.3V、2.5V、1.8V、1.5V 和 1.2V），那(nei)么在演示板(ban)上用一(yi)(yi)(yi)條跨接線可(ke)以(yi)非(fei)(fei)常(chang)(chang)容(rong)易(yi)地(di)改變(bian)這(zhe)個(ge)(ge)(ge)輸(shu)(shu)出(chu)電(dian)(dian)壓(ya)(ya)。

　　總之，兩塊(kuai) BP 太(tai)陽能電池板，每塊(kuai)在 4A 電流時都有 0 至(zhi) 20V 的(de)(de)(de)輸出，這(zhe)兩塊(kuai)太(tai)陽能電池板由 20V 輸出的(de)(de)(de) LTM4607 降(jiang)壓(ya)(ya)/升壓(ya)(ya)型(xing)微(wei)型(xing)模塊(kuai)開關(guan)穩(wen)壓(ya)(ya)器調(diao)節，然后再到 14V 輸入的(de)(de)(de) LTC1435/LT1620 電池充電器，通(tong)過(guo)一(yi)個(ge)理想二極管 MOSFET 控(kong)制(zhi)(zhi)器 LTC4414、一(yi)個(ge)串聯的(de)(de)(de)電流檢測放大器 LTC6103，最終進入電池；以(yi)穩(wen)定的(de)(de)(de) 4A 電流充電。在這(zhe)個(ge)設計中，由 LTC2418 在不同的(de)(de)(de)級獲取(qu) ADC 讀數(shu)，并將讀數(shu)送至(zhi)由 LTM4601 微(wei)型(xing)模塊(kuai)開關(guan)穩(wen)壓(ya)(ya)器供電的(de)(de)(de) DC590B 演(yan)示板微(wei)控(kong)制(zhi)(zhi)器，以(yi)在 LCD 上(shang)顯示結(jie)果。圖 7 顯示正在運(yun)行的(de)(de)(de)整個(ge)系統(tong)。

　　圖 7：運行(xing)中(zhong)的(de)整(zheng)個系(xi)統(tong)設計

　　噴霧系統的機械設計

　　有了(le)(le)一(yi)(yi)個正(zheng)常(chang)工作的太陽能充電器(qi)和穩(wen)定(ding)的 12V 輸出，我就(jiu)準備好著手(shou)組裝噴霧(wu)系統(tong)了(le)(le)。去一(yi)(yi)趟五(wu)金(jin)店就(jiu)得到(dao)了(le)(le)我需要的材料：艙(cang)底污(wu)水(shui)(shui)(shui)(shui)泵、水(shui)(shui)(shui)(shui)龍帶連接(jie)器(qi)、水(shui)(shui)(shui)(shui)龍帶夾(jia)具、轉接(jie)器(qi)和噴霧(wu)系統(tong)。水(shui)(shui)(shui)(shui)龍帶長約 15 英(ying)尺(chi)，擰在(zai)轉接(jie)器(qi)螺(luo)釘上(shang)，用水(shui)(shui)(shui)(shui)龍帶夾(jia)具固定(ding)到(dao)水(shui)(shui)(shui)(shui)泵上(shang)，噴霧(wu)系統(tong)固定(ding)在(zai)末端，有 5 個噴霧(wu)嘴。底艙(cang)污(wu)水(shui)(shui)(shui)(shui)泵靠最大值為(wei) 12V 的電壓運(yun)行，水(shui)(shui)(shui)(shui)壓可以通(tong)過降低(di)電壓來控制。

　　為了實(shi)現靈活(huo)性(xing)，我安裝了一(yi)個(ge)穩(wen)壓(ya)器，該穩(wen)壓(ya)器可以(yi)接(jie)受 12V 輸(shu)入(ru)(ru)，并將輸(shu)入(ru)(ru)轉換成可變(bian)的(de)(de) 12V 輸(shu)出(chu)(chu)(chu)。這要求 LTM4607 設計有降(jiang)壓(ya)/升壓(ya)特(te)性(xing)。該器件使(shi)用一(yi)個(ge)反饋電(dian)(dian)阻(zu)器控制輸(shu)出(chu)(chu)(chu)電(dian)(dian)壓(ya)。一(yi)個(ge) 50k 的(de)(de)可變(bian)旋(xuan)鈕電(dian)(dian)位器取代了電(dian)(dian)阻(zu)器，從而(er)非(fei)常容易控制 0.8V 至 12V 的(de)(de)輸(shu)出(chu)(chu)(chu)。還(huan)串(chuan)聯(lian)了一(yi)個(ge) 5.62k 的(de)(de)電(dian)(dian)阻(zu)器，以(yi)限(xian)制輸(shu)出(chu)(chu)(chu)電(dian)(dian)壓(ya)，保持輸(shu)出(chu)(chu)(chu)低于(yu) 15V.該設計通過旋(xuan)轉一(yi)個(ge)旋(xuan)鈕實(shi)現了水壓(ya)控制。

　　然(ran)后，我(wo)就可以測試我(wo)的全(quan)功(gong)能(neng)噴霧(wu)系(xi)(xi)統了。結果，水(shui)泵(beng)(beng)導致最大(da)約 6A 的電池(chi)放(fang)電電流，這(zhe)意味著，在峰值輸出時，水(shui)泵(beng)(beng)約從每塊太陽能(neng)電池(chi)板獲得 4A 電流。控制水(shui)泵(beng)(beng)速度和壓力(li)的好處(chu)是(shi)，我(wo)可以將壓力(li)降到(dao)足(zu)夠低(di)，以降低(di)電池(chi)的放(fang)電電流，并全(quan)部(bu)靠太陽能(neng)電池(chi)板運行(xing)水(shui)泵(beng)(beng)，以節省(sheng)電池(chi)電量，這(zhe)樣做非常(chang)有效。通過這(zhe)種方(fang)法，我(wo)們能(neng)夠在營地全(quan)天運行(xing)噴霧(wu)系(xi)(xi)統，而不必擔心電池(chi)放(fang)電，耽誤(wu)夜間用于 LED 照(zhao)明系(xi)(xi)統。

　　LED 照明

　　隨著電(dian)源(yuan)的(de)(de)(de)完成，我(wo)就可(ke)以增加電(dian)路，在(zai)(zai)(zai)晚上高效(xiao)率地(di)(di)提供(gong)(gong)(gong)照明(ming)了(le)(le)。LED 足夠(gou)亮，可(ke)以照亮房(fang)間，這(zhe)在(zai)(zai)(zai)以前是(shi)不(bu)可(ke)想象的(de)(de)(de)，但是(shi)新(xin)的(de)(de)(de)技(ji)術進步已經(jing)為 LED 照明(ming)的(de)(de)(de)新(xin)時(shi)代創(chuang)造了(le)(le)條件。尤(you)其是(shi)，PhilipsLumileds Luxeon LED 在(zai)(zai)(zai) 1000mA 時(shi)可(ke)以提供(gong)(gong)(gong)超(chao)過(guo) 100 流明(ming)的(de)(de)(de)光。我(wo)配備了(le)(le)一(yi)個(ge) LumiLED 陣(zhen)列，使(shi)用 LTC3475 （16 引線 TSSOP 耐熱增強型封裝） 雙(shuang)路 1.5A 恒(heng)定電(dian)流 LED 驅(qu)動器(qi) DC923A 演示(shi)板。它設(she)計成用一(yi)個(ge)寬范圍(wei)輸(shu)入電(dian)壓 （4V 至 30V） 驅(qu)動兩(liang)(liang)個(ge)信道，每個(ge)信道 1.5A.12V 電(dian)池(chi)直接(jie)連接(jie)到演示(shi)板的(de)(de)(de)輸(shu)入，為每個(ge)通道 3 個(ge)串聯的(de)(de)(de) LED 燈供(gong)(gong)(gong)電(dian)，當兩(liang)(liang)個(ge)通道都接(jie)通時(shi)，總共有 6 個(ge) LED.這(zhe)些 LED 出(chu)奇地(di)(di)亮，用一(yi)塊柔光布遮上時(shi)，足夠(gou)照亮我(wo)們整個(ge)營地(di)(di)。晚上的(de)(de)(de)放電(dian)電(dian)流全部來自電(dian)池(chi)，因(yin)為太陽(yang)能電(dian)池(chi)板夜間提供(gong)(gong)(gong)零電(dian)力(li)。以 2A 的(de)(de)(de)總放電(dian)電(dian)流，可(ke)以整晚為這(zhe)些燈供(gong)(gong)(gong)電(dian)。到接(jie)近中午(wu)或偏下午(wu)時(shi)，電(dian)池(chi)再次充滿電(dian)，為給噴(pen)霧系統供(gong)(gong)(gong)電(dian)做(zuo)好了(le)(le)準備，在(zai)(zai)(zai)早(zao)午(wu)餐后(hou)，噴(pen)霧系統就可(ke)以讓我(wo)們感到涼爽了(le)(le)。