1 概 述

　　電子信息技術的快速發展使得各種各樣的電子產品不斷涌現，并朝著便攜和小型輕量化的趨勢發展，這也使得更多的電氣化產品采用基于電池的供電系統。目前，較多使用的電池有鎳鎘、鎳氫、鉛蓄電池和鋰電池，由于它們各自的優缺點使得它們在相當長的時期內將共存發展［4］。由于不同類型的電池的充電特性不同，目前通常對不同類型，甚至不同電壓、容量等級的電池使用不同的充電器，這(zhe)在(zai)(zai)實際使(shi)用中有(you)諸多不便。本(ben)文(wen)設(she)計了一(yi)種(zhong)通用型的(de)充電(dian)(dian)(dian)(dian)(dian)(dian)器，可對電(dian)(dian)(dian)(dian)(dian)(dian)壓等級(ji)(ji)為1.2V～48V的(de)鎳(nie)鎘(ge)、鎳(nie)氫、鉛蓄電(dian)(dian)(dian)(dian)(dian)(dian)池和(he)鋰電(dian)(dian)(dian)(dian)(dian)(dian)池進(jin)行(xing)充電(dian)(dian)(dian)(dian)(dian)(dian)。為達到如此寬的(de)充電(dian)(dian)(dian)(dian)(dian)(dian)范圍(wei)，充電(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)源采(cai)用二級(ji)(ji)電(dian)(dian)(dian)(dian)(dian)(dian)路(lu)拓撲，并(bing)使(shi)用同一(yi)PWM信號(hao)源對兩級(ji)(ji)電(dian)(dian)(dian)(dian)(dian)(dian)路(lu)進(jin)行(xing)聯(lian)動控(kong)(kong)制(zhi)(zhi)。該電(dian)(dian)(dian)(dian)(dian)(dian)源在(zai)(zai) 85VAC～265VAC的(de)通用輸入范圍(wei)內均可實現1.2V（0.3A）～60V（1.6A）的(de)寬范圍(wei)輸出(chu)。同時(shi)使(shi)用單片機進(jin)行(xing)充電(dian)(dian)(dian)(dian)(dian)(dian)控(kong)(kong)制(zhi)(zhi)，先進(jin)的(de)慢脈(mo)沖快(kuai)速充電(dian)(dian)(dian)(dian)(dian)(dian)法［4］，并(bing)綜合使(shi)用定時(shi)控(kong)(kong)制(zhi)(zhi)、電(dian)(dian)(dian)(dian)(dian)(dian)壓控(kong)(kong)制(zhi)(zhi)和(he)溫度(du)控(kong)(kong)制(zhi)(zhi)來中止快(kuai)速充電(dian)(dian)(dian)(dian)(dian)(dian)，確保不會因過充電(dian)(dian)(dian)(dian)(dian)(dian)而損傷電(dian)(dian)(dian)(dian)(dian)(dian)池。

　　2 充電電源的拓撲結構和控制方案

　　由于要求充電(dian)(dian)電(dian)(dian)源(yuan)的輸(shu)(shu)出(chu)變(bian)化(hua)范(fan)(fan)圍為(wei)1.2V（0.3A）～60V（1.6A），采(cai)用單級(ji)(ji)變(bian)換器(qi)很難實現這 么(me)大的變(bian)化(hua)范(fan)(fan)圍，故采(cai)用了兩級(ji)(ji)結構，電(dian)(dian)源(yuan)主電(dian)(dian)路如(ru)圖1所示，交流輸(shu)(shu)入(ru)經(jing)(jing)整(zheng)流濾波得到穩定的直流電(dian)(dian)壓DCin，首先經(jing)(jing)單端(duan)反激(ji)變(bian)換器(qi)預穩壓，并實現輸(shu)(shu)入(ru)級(ji)(ji)與輸(shu)(shu)出(chu)級(ji)(ji)的隔離，然后再經(jing)(jing)BUCK變(bian)換器(qi)進一步降壓，得到所需輸(shu)(shu)出(chu)電(dian)(dian)壓。為(wei)了保證單端(duan)反激(ji)變(bian)換器(qi)能(neng)穩定工作，加(jia)入(ru)了假負載R2。由于電(dian)(dian)池等效于一個大電(dian)(dian)容，故輸(shu)(shu)出(chu)端(duan)可不加(jia)濾波電(dian)(dian)容。

　　為簡化(hua)(hua)控(kong)(kong)制，采用(yong)同一(yi)PWM信(xin)(xin)號(hao)(hao)對兩級(ji)(ji)變(bian)換(huan)器進(jin)行聯動控(kong)(kong)制。單端(duan)反激變(bian)換(huan)器的(de)的(de)占(zhan)空(kong)比一(yi)般應(ying)不超(chao)過0.5，以減小開關(guan)管電(dian)壓應(ying)力，而BUCK變(bian)換(huan)器則希望盡量提高占(zhan)空(kong)比，以改善(shan)輸(shu)出電(dian)壓波形和動態響應(ying)，因(yin)此，在保證(zheng)能(neng)夠實現所要求的(de)輸(shu)出變(bian)化(hua)(hua)范圍的(de)情況下(xia)，應(ying)盡量提高BUCK變(bian)換(huan)器的(de)占(zhan)空(kong)比，這樣(yang)就不能(neng)采用(yong)完全(quan)相(xiang)同的(de)PWM信(xin)(xin)號(hao)(hao)同時控(kong)(kong)制兩級(ji)(ji)變(bian)換(huan)器。為此，本文給出了一(yi)種相(xiang)對簡單的(de)控(kong)(kong)制策略(lve)，使用(yong)同一(yi) PWM信(xin)(xin)號(hao)(hao)變(bian)換(huan)出占(zhan)空(kong)比不同的(de)兩路PWM信(xin)(xin)號(hao)(hao)，分別(bie)控(kong)(kong)制兩級(ji)(ji)變(bian)換(huan)器，具體實現方法(fa)如(ru)下(xia)所述。

　　對于任一(yi)方波信(xin)(xin)號(hao)(hao)，要改變(bian)(bian)其(qi)占空比（對應于導(dao)(dao)通(tong)時間，即信(xin)(xin)號(hao)(hao)處于高電(dian)(dian)平狀態的(de)(de)(de)時間），一(yi)般有兩(liang)種實現途徑：一(yi)是改變(bian)(bian)其(qi)導(dao)(dao)通(tong)時間而頻(pin)率(lv)保持(chi)不(bu)變(bian)(bian)，二(er)是改變(bian)(bian)其(qi)頻(pin)率(lv)而導(dao)(dao)通(tong)時間保持(chi)不(bu)變(bian)(bian)。本(ben)文采用(yong)后一(yi)種途徑，即用(yong)PWM控制器(qi)輸出(chu)的(de)(de)(de)信(xin)(xin)號(hao)(hao)直接(jie)控制BUCK變(bian)(bian)換器(qi)，而在(zai)保持(chi)導(dao)(dao)通(tong)時間不(bu)變(bian)(bian)的(de)(de)(de)情況下(xia)將(jiang)其(qi)信(xin)(xin)號(hao)(hao)進行二(er)分頻(pin)，得到(dao)占空比減半(ban)的(de)(de)(de)信(xin)(xin)號(hao)(hao)來控制單端反激變(bian)(bian)換器(qi)。具體實現電(dian)(dian)路如圖2（a）所示，源信(xin)(xin)號(hao)(hao)經分頻(pin)器(qi)二(er)分頻(pin)，得到(dao)頻(pin)率(lv)減半(ban)的(de)(de)(de)信(xin)(xin)號(hao)(hao)，再(zai)與(yu)源信(xin)(xin)號(hao)(hao)相與(yu)，即得到(dao)導(dao)(dao)通(tong)時間不(bu)變(bian)(bian)而頻(pin)率(lv)減半(ban)的(de)(de)(de)信(xin)(xin)號(hao)(hao)。電(dian)(dian)路中各點波形(xing)參見圖2（b）。

 3 充電控制(zhi)方案

　　近年(nian)來，如何對電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)高(gao)效(xiao)、快(kuai)速(su)地(di)充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)成為充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)技術研究(jiu)的(de)熱點，國內外研究(jiu)人員也提出(chu)了不少快(kuai)速(su)充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)方(fang)法，本文(wen)即參考了其中一種較(jiao)實用的(de)慢脈(mo)沖(chong)快(kuai)速(su)充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)法，這種方(fang)法能確保在(zai)充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)過程中及時消除(chu)或(huo)降低電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)極化，電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)析(xi)氣(qi)量少，溫升低，充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)效(xiao)率高(gao)。整(zheng)個充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)過程由(you)恒流(liu)和恒壓充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)兩(liang)(liang)個階段組成，在(zai)每一階段均(jun)以周(zhou)期為幾秒到(dao)幾十(shi)秒的(de)電(dian)(dian)(dian)(dian)(dian)(dian)流(liu)或(huo)電(dian)(dian)(dian)(dian)(dian)(dian)壓脈(mo)沖(chong)進行充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)。而(er)兩(liang)(liang)階段的(de)轉換時刻(ke)則由(you)電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)的(de)充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)狀態所決定。

　　由(you)于(yu)充(chong)(chong)電(dian)(dian)(dian)方法(fa)相(xiang)對較復(fu)雜，且(qie)需要對多(duo)種類型和(he)規(gui)格(ge)的(de)(de)(de)電(dian)(dian)(dian)池進(jin)行充(chong)(chong)電(dian)(dian)(dian)，故需要采用可編程(cheng)器(qi)件進(jin)行控制，而單(dan)(dan)片(pian)機(ji)(ji)以其相(xiang)對強大的(de)(de)(de)功能和(he)低廉的(de)(de)(de)價格(ge)成為首選。本文選用Motorola公(gong)司推出(chu)的(de)(de)(de) MC68HC908GP32作為主控元件，整(zheng)個(ge)系統(tong)的(de)(de)(de)組成框圖如(ru)圖3所示，反映電(dian)(dian)(dian)池充(chong)(chong)電(dian)(dian)(dian)狀態的(de)(de)(de)充(chong)(chong)電(dian)(dian)(dian)電(dian)(dian)(dian)流(liu)、電(dian)(dian)(dian)池電(dian)(dian)(dian)壓(ya)和(he)溫度信號經采樣電(dian)(dian)(dian)路送入單(dan)(dan)片(pian)機(ji)(ji)的(de)(de)(de)A/D 轉換(huan)口，單(dan)(dan)片(pian)機(ji)(ji)根(gen)據充(chong)(chong)電(dian)(dian)(dian)算法(fa)，通過D/A轉換(huan)口輸出(chu)信號控制充(chong)(chong)電(dian)(dian)(dian)電(dian)(dian)(dian)源的(de)(de)(de)電(dian)(dian)(dian)壓(ya)或電(dian)(dian)(dian)流(liu)給定，從而達到控制充(chong)(chong)電(dian)(dian)(dian)電(dian)(dian)(dian)源輸出(chu)的(de)(de)(de)目的(de)(de)(de)。

　　軟件系統(tong)(tong)采用模塊(kuai)化設計方法(fa)，整(zheng)(zheng)個程(cheng)(cheng)序由(you)主程(cheng)(cheng)序模塊(kuai)、各(ge)(ge)類電池充電子程(cheng)(cheng)序模塊(kuai)以(yi)及錯(cuo)誤(wu)處理(li)模塊(kuai)組成，各(ge)(ge)模塊(kuai)相對獨立，以(yi)便于算法(fa)改(gai)進及功能擴(kuo)充，其中主程(cheng)(cheng)序模塊(kuai)構架了軟件系統(tong)(tong)的骨(gu)架，通過(guo)其對其他模塊(kuai)的調用來實現完整(zheng)(zheng)的充電過(guo)程(cheng)(cheng)控制，其流程(cheng)(cheng)圖見圖4。

　　為確(que)保充(chong)(chong)電安(an)全，在開始(shi)充(chong)(chong)電前檢測電池(chi)電壓(ya)和(he)溫(wen)(wen)度(du)，以排除(chu)電池(chi)接反、用(yong)戶選擇的(de)電池(chi)規格有誤等錯誤，并判斷電池(chi)的(de)狀態是否(fou)適合(he)快速充(chong)(chong)電，如電池(chi)電壓(ya)或溫(wen)(wen)度(du)過(guo)低，則(ze)需要(yao)進行小電流預(yu)充(chong)(chong)電，待(dai)電池(chi)電壓(ya)、溫(wen)(wen)度(du)達(da)到正常范圍(wei)后再開始(shi)快速充(chong)(chong)電。在整個(ge)充(chong)(chong)電過(guo)程中均實時(shi)檢測電池(chi)電壓(ya)和(he)溫(wen)(wen)度(du)，并綜(zong)合(he)采用(yong)最(zui)高電壓(ya)控(kong)制(zhi)(zhi)、電壓(ya)零增量控(kong)制(zhi)(zhi)、最(zui)高溫(wen)(wen)度(du)控(kong)制(zhi)(zhi)和(he)定時(shi)控(kong)制(zhi)(zhi)等方法來(lai)終止快速充(chong)(chong)電，以確(que)保電池(chi)不被過(guo)充(chong)(chong)。

　　4 實驗及結論

　　本文采用清華大學Motorola單片機應用開發研究中心推出的MC68HC908GP32IDK作為開發系統［2］，對該充電器進行(xing)了(le)實驗測試，在(zai)整個負載(zai)范圍內均有穩定的輸(shu)出，開關管的最小導通(tong)時(shi)間（對應(ying)于最小負載(zai)）約為1.2us，而開關管（MTP4N80）的開關時(shi)間和反向恢復時(shi)間之和小于0.7us，故充電(dian)電(dian)源能穩定工作。

　　本文設計了一個通用型智能充電器，給出了(le)寬范圍充(chong)(chong)電電源的(de)(de)一種實現(xian)方法，并充(chong)(chong)分利用了(le)單片機強大的(de)(de)控制功(gong)能(neng)，絕大部分功(gong)能(neng)由軟件(jian)編(bian)程實現(xian)，使(shi)得系統對(dui)硬件(jian)的(de)(de)依(yi)賴性(xing)較小，便于功(gong)能(neng)的(de)(de)擴充(chong)(chong)及(ji)改進。