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，這在(zai)(zai)實(shi)際(ji)使(shi)用(yong)中有諸多不便。本文(wen)設計(ji)了一種(zhong)通用(yong)型的(de)充(chong)(chong)(chong)電(dian)(dian)器，可對電(dian)(dian)壓等級(ji)為(wei)1.2V～48V的(de)鎳鎘、鎳氫、鉛蓄電(dian)(dian)池和鋰電(dian)(dian)池進行(xing)充(chong)(chong)(chong)電(dian)(dian)。為(wei)達到(dao)如此寬(kuan)的(de)充(chong)(chong)(chong)電(dian)(dian)范圍(wei)(wei)(wei)，充(chong)(chong)(chong)電(dian)(dian)電(dian)(dian)源(yuan)采用(yong)二級(ji)電(dian)(dian)路拓撲(pu)，并(bing)使(shi)用(yong)同(tong)一PWM信號(hao)源(yuan)對兩級(ji)電(dian)(dian)路進行(xing)聯動控制(zhi)(zhi)。該電(dian)(dian)源(yuan)在(zai)(zai) 85VAC～265VAC的(de)通用(yong)輸入范圍(wei)(wei)(wei)內(nei)均可實(shi)現1.2V（0.3A）～60V（1.6A）的(de)寬(kuan)范圍(wei)(wei)(wei)輸出。同(tong)時使(shi)用(yong)單(dan)片機(ji)進行(xing)充(chong)(chong)(chong)電(dian)(dian)控制(zhi)(zhi)，先(xian)進的(de)慢脈沖快(kuai)速(su)充(chong)(chong)(chong)電(dian)(dian)法［4］，并(bing)綜合使(shi)用(yong)定時控制(zhi)(zhi)、電(dian)(dian)壓控制(zhi)(zhi)和溫度控制(zhi)(zhi)來中止(zhi)快(kuai)速(su)充(chong)(chong)(chong)電(dian)(dian)，確保不會因過充(chong)(chong)(chong)電(dian)(dian)而損傷(shang)電(dian)(dian)池。

　　2 充電電源的拓撲結構和控制方案

　　由(you)于(yu)(yu)要求充電(dian)(dian)電(dian)(dian)源(yuan)的(de)輸出變化范圍(wei)為1.2V（0.3A）～60V（1.6A），采用單(dan)(dan)級變換(huan)器(qi)(qi)很難實現(xian)這 么大的(de)變化范圍(wei)，故采用了(le)(le)兩級結構，電(dian)(dian)源(yuan)主電(dian)(dian)路如圖1所示，交流輸入(ru)(ru)經整流濾波得到穩(wen)(wen)定(ding)的(de)直(zhi)流電(dian)(dian)壓(ya)DCin，首先經單(dan)(dan)端(duan)(duan)反(fan)激變換(huan)器(qi)(qi)預穩(wen)(wen)壓(ya)，并實現(xian)輸入(ru)(ru)級與(yu)輸出級的(de)隔(ge)離，然(ran)后再經BUCK變換(huan)器(qi)(qi)進一(yi)步降壓(ya)，得到所需輸出電(dian)(dian)壓(ya)。為了(le)(le)保(bao)證(zheng)單(dan)(dan)端(duan)(duan)反(fan)激變換(huan)器(qi)(qi)能穩(wen)(wen)定(ding)工(gong)作(zuo)，加入(ru)(ru)了(le)(le)假負(fu)載R2。由(you)于(yu)(yu)電(dian)(dian)池等效于(yu)(yu)一(yi)個大電(dian)(dian)容，故輸出端(duan)(duan)可不加濾波電(dian)(dian)容。

　　為(wei)簡化(hua)控制(zhi)，采(cai)用(yong)同一(yi)(yi)(yi)PWM信(xin)(xin)號(hao)對(dui)兩(liang)級變(bian)換器(qi)(qi)進行聯動控制(zhi)。單(dan)端反激變(bian)換器(qi)(qi)的(de)(de)的(de)(de)占(zhan)空比(bi)(bi)一(yi)(yi)(yi)般(ban)應不超過0.5，以(yi)減小開關管電壓應力，而BUCK變(bian)換器(qi)(qi)則希望(wang)盡(jin)量提高占(zhan)空比(bi)(bi)，以(yi)改善(shan)輸(shu)出(chu)電壓波形和動態響應，因(yin)此，在(zai)保證能(neng)夠實(shi)現所要求的(de)(de)輸(shu)出(chu)變(bian)化(hua)范圍的(de)(de)情(qing)況下，應盡(jin)量提高BUCK變(bian)換器(qi)(qi)的(de)(de)占(zhan)空比(bi)(bi)，這(zhe)樣就不能(neng)采(cai)用(yong)完全相同的(de)(de)PWM信(xin)(xin)號(hao)同時控制(zhi)兩(liang)級變(bian)換器(qi)(qi)。為(wei)此，本(ben)文(wen)給出(chu)了一(yi)(yi)(yi)種相對(dui)簡單(dan)的(de)(de)控制(zhi)策略(lve)，使用(yong)同一(yi)(yi)(yi) PWM信(xin)(xin)號(hao)變(bian)換出(chu)占(zhan)空比(bi)(bi)不同的(de)(de)兩(liang)路PWM信(xin)(xin)號(hao)，分(fen)別控制(zhi)兩(liang)級變(bian)換器(qi)(qi)，具體實(shi)現方(fang)法如(ru)下所述(shu)。

　　對于任一(yi)(yi)(yi)方波信(xin)(xin)(xin)號(hao)，要(yao)改(gai)(gai)變(bian)(bian)(bian)其占(zhan)空比（對應于導通時(shi)(shi)間(jian)(jian)，即(ji)信(xin)(xin)(xin)號(hao)處于高電平(ping)狀態的時(shi)(shi)間(jian)(jian)），一(yi)(yi)(yi)般有兩種實現(xian)途(tu)徑：一(yi)(yi)(yi)是(shi)改(gai)(gai)變(bian)(bian)(bian)其導通時(shi)(shi)間(jian)(jian)而頻(pin)(pin)(pin)率(lv)(lv)保(bao)(bao)持不變(bian)(bian)(bian)，二是(shi)改(gai)(gai)變(bian)(bian)(bian)其頻(pin)(pin)(pin)率(lv)(lv)而導通時(shi)(shi)間(jian)(jian)保(bao)(bao)持不變(bian)(bian)(bian)。本文采用(yong)后一(yi)(yi)(yi)種途(tu)徑，即(ji)用(yong)PWM控制(zhi)器輸出的信(xin)(xin)(xin)號(hao)直接控制(zhi)BUCK變(bian)(bian)(bian)換(huan)器，而在保(bao)(bao)持導通時(shi)(shi)間(jian)(jian)不變(bian)(bian)(bian)的情況下將(jiang)其信(xin)(xin)(xin)號(hao)進行二分(fen)頻(pin)(pin)(pin)，得到占(zhan)空比減(jian)半(ban)的信(xin)(xin)(xin)號(hao)來(lai)控制(zhi)單端(duan)反激變(bian)(bian)(bian)換(huan)器。具體實現(xian)電路如圖2（a）所示，源信(xin)(xin)(xin)號(hao)經分(fen)頻(pin)(pin)(pin)器二分(fen)頻(pin)(pin)(pin)，得到頻(pin)(pin)(pin)率(lv)(lv)減(jian)半(ban)的信(xin)(xin)(xin)號(hao)，再與源信(xin)(xin)(xin)號(hao)相與，即(ji)得到導通時(shi)(shi)間(jian)(jian)不變(bian)(bian)(bian)而頻(pin)(pin)(pin)率(lv)(lv)減(jian)半(ban)的信(xin)(xin)(xin)號(hao)。電路中各點波形參見圖2（b）。

 3 充電控(kong)制方案

　　近年來，如何對電(dian)(dian)池(chi)(chi)高(gao)效(xiao)、快(kuai)(kuai)速(su)地充(chong)(chong)電(dian)(dian)成為(wei)充(chong)(chong)電(dian)(dian)技術研究的(de)熱點，國內(nei)外研究人員也提(ti)出了不少快(kuai)(kuai)速(su)充(chong)(chong)電(dian)(dian)方法(fa)(fa)，本文即參(can)考(kao)了其中一(yi)種(zhong)(zhong)較(jiao)實用(yong)的(de)慢脈(mo)沖快(kuai)(kuai)速(su)充(chong)(chong)電(dian)(dian)法(fa)(fa)，這種(zhong)(zhong)方法(fa)(fa)能確保在充(chong)(chong)電(dian)(dian)過程中及時(shi)消除(chu)或降低(di)電(dian)(dian)池(chi)(chi)極(ji)化(hua)，電(dian)(dian)池(chi)(chi)析氣(qi)量(liang)少，溫升低(di)，充(chong)(chong)電(dian)(dian)效(xiao)率高(gao)。整個充(chong)(chong)電(dian)(dian)過程由(you)恒流(liu)和恒壓充(chong)(chong)電(dian)(dian)兩個階(jie)(jie)段組(zu)成，在每(mei)一(yi)階(jie)(jie)段均以周期為(wei)幾(ji)秒(miao)到幾(ji)十秒(miao)的(de)電(dian)(dian)流(liu)或電(dian)(dian)壓脈(mo)沖進(jin)行(xing)充(chong)(chong)電(dian)(dian)。而兩階(jie)(jie)段的(de)轉(zhuan)換(huan)時(shi)刻則由(you)電(dian)(dian)池(chi)(chi)的(de)充(chong)(chong)電(dian)(dian)狀態(tai)所決定。

　　由于充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)方法相(xiang)對(dui)較復雜，且需(xu)要對(dui)多種類型和(he)規(gui)格(ge)的(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)池進(jin)行充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)，故需(xu)要采(cai)用可(ke)編程器件進(jin)行控(kong)(kong)制(zhi)，而單片機以其相(xiang)對(dui)強大的(de)(de)(de)功(gong)能(neng)和(he)低廉的(de)(de)(de)價(jia)格(ge)成(cheng)為(wei)(wei)首選。本文選用Motorola公司推出(chu)的(de)(de)(de) MC68HC908GP32作為(wei)(wei)主控(kong)(kong)元(yuan)件，整(zheng)個系統的(de)(de)(de)組成(cheng)框圖如圖3所示(shi)，反(fan)映電(dian)(dian)(dian)(dian)(dian)(dian)池充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)狀態的(de)(de)(de)充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)流、電(dian)(dian)(dian)(dian)(dian)(dian)池電(dian)(dian)(dian)(dian)(dian)(dian)壓和(he)溫度信號經(jing)采(cai)樣電(dian)(dian)(dian)(dian)(dian)(dian)路送入單片機的(de)(de)(de)A/D 轉換(huan)(huan)口(kou)(kou)，單片機根(gen)據充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)算法，通過D/A轉換(huan)(huan)口(kou)(kou)輸出(chu)信號控(kong)(kong)制(zhi)充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)的(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)壓或電(dian)(dian)(dian)(dian)(dian)(dian)流給定，從(cong)而達(da)到控(kong)(kong)制(zhi)充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)輸出(chu)的(de)(de)(de)目(mu)的(de)(de)(de)。

　　軟件系(xi)統(tong)采用(yong)模(mo)(mo)塊化設計方法，整(zheng)個程(cheng)序(xu)由主程(cheng)序(xu)模(mo)(mo)塊、各(ge)類電池充電子(zi)程(cheng)序(xu)模(mo)(mo)塊以及(ji)錯誤處理模(mo)(mo)塊組成，各(ge)模(mo)(mo)塊相(xiang)對(dui)獨立，以便于算法改進及(ji)功能擴充，其(qi)中主程(cheng)序(xu)模(mo)(mo)塊構(gou)架了軟件系(xi)統(tong)的骨(gu)架，通過其(qi)對(dui)其(qi)他模(mo)(mo)塊的調用(yong)來實現完整(zheng)的充電過程(cheng)控制(zhi)，其(qi)流(liu)程(cheng)圖見圖4。

　　為確(que)保(bao)充(chong)電(dian)(dian)(dian)(dian)(dian)(dian)安(an)全，在開(kai)始充(chong)電(dian)(dian)(dian)(dian)(dian)(dian)前(qian)檢(jian)測(ce)電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)和溫(wen)度(du)，以排除電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)接反、用戶選擇(ze)的電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)規格有誤等錯誤，并判斷電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)的狀態是否(fou)適(shi)合快速充(chong)電(dian)(dian)(dian)(dian)(dian)(dian)，如電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)或溫(wen)度(du)過(guo)低，則需(xu)要進行小(xiao)電(dian)(dian)(dian)(dian)(dian)(dian)流預充(chong)電(dian)(dian)(dian)(dian)(dian)(dian)，待電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)、溫(wen)度(du)達到正(zheng)常范圍后再(zai)開(kai)始快速充(chong)電(dian)(dian)(dian)(dian)(dian)(dian)。在整個(ge)充(chong)電(dian)(dian)(dian)(dian)(dian)(dian)過(guo)程中均實時檢(jian)測(ce)電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)和溫(wen)度(du)，并綜合采(cai)用最高電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)控(kong)(kong)制、電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)零增量控(kong)(kong)制、最高溫(wen)度(du)控(kong)(kong)制和定時控(kong)(kong)制等方法(fa)來(lai)終止(zhi)快速充(chong)電(dian)(dian)(dian)(dian)(dian)(dian)，以確(que)保(bao)電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)不被過(guo)充(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(jin)行了實驗測試，在整個負載(zai)范圍內(nei)均有穩(wen)定的(de)輸出，開(kai)關(guan)管的(de)最小導通時間（對(dui)應(ying)于最小負載(zai)）約(yue)為1.2us，而開(kai)關(guan)管（MTP4N80）的(de)開(kai)關(guan)時間和反向恢復時間之(zhi)和小于0.7us，故充(chong)電(dian)電(dian)源能(neng)穩(wen)定工作。

　　本文設計了一個通用型智能充電器，給出了(le)寬(kuan)范圍(wei)充(chong)(chong)電(dian)(dian)電(dian)(dian)源的一種實現(xian)方法，并充(chong)(chong)分(fen)利用了(le)單片(pian)機強大(da)(da)的控制功(gong)能，絕大(da)(da)部分(fen)功(gong)能由軟件(jian)(jian)編程實現(xian)，使得系(xi)統對硬件(jian)(jian)的依賴性較小(xiao)，便于功(gong)能的擴充(chong)(chong)及改進。