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，這在實際使(shi)(shi)用(yong)中有諸多不(bu)便。本文設(she)計(ji)了一種通用(yong)型的(de)(de)充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)器，可對電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓等級為1.2V～48V的(de)(de)鎳(nie)鎘、鎳(nie)氫、鉛蓄(xu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池和鋰電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池進行充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)。為達(da)到如此寬的(de)(de)充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)范(fan)圍，充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)采用(yong)二級電(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)拓撲，并(bing)使(shi)(shi)用(yong)同一PWM信號源(yuan)對兩級電(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)進行聯動控制(zhi)(zhi)。該電(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)在 85VAC～265VAC的(de)(de)通用(yong)輸(shu)入范(fan)圍內均可實現(xian)1.2V（0.3A）～60V（1.6A）的(de)(de)寬范(fan)圍輸(shu)出。同時(shi)使(shi)(shi)用(yong)單片機進行充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)控制(zhi)(zhi)，先(xian)進的(de)(de)慢脈沖(chong)快(kuai)速充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)法(fa)［4］，并(bing)綜合使(shi)(shi)用(yong)定時(shi)控制(zhi)(zhi)、電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓控制(zhi)(zhi)和溫度控制(zhi)(zhi)來中止快(kuai)速充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)，確保不(bu)會因過(guo)充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)而(er)損傷電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池。

　　2 充電電源的拓撲結構和控制方案

　　由(you)于(yu)要求充電(dian)(dian)電(dian)(dian)源的(de)輸(shu)出變(bian)(bian)化范(fan)圍為(wei)1.2V（0.3A）～60V（1.6A），采用單(dan)級(ji)變(bian)(bian)換(huan)(huan)器很難(nan)實現這(zhe) 么大(da)的(de)變(bian)(bian)化范(fan)圍，故采用了(le)兩(liang)級(ji)結構，電(dian)(dian)源主電(dian)(dian)路(lu)如圖1所示，交流輸(shu)入經(jing)(jing)整流濾波得(de)到(dao)穩定的(de)直流電(dian)(dian)壓DCin，首先經(jing)(jing)單(dan)端反激變(bian)(bian)換(huan)(huan)器預穩壓，并(bing)實現輸(shu)入級(ji)與輸(shu)出級(ji)的(de)隔離，然后再經(jing)(jing)BUCK變(bian)(bian)換(huan)(huan)器進一(yi)步降壓，得(de)到(dao)所需輸(shu)出電(dian)(dian)壓。為(wei)了(le)保證(zheng)單(dan)端反激變(bian)(bian)換(huan)(huan)器能穩定工作，加入了(le)假負載R2。由(you)于(yu)電(dian)(dian)池等效于(yu)一(yi)個大(da)電(dian)(dian)容(rong)，故輸(shu)出端可不加濾波電(dian)(dian)容(rong)。

　　為(wei)(wei)簡化控(kong)制，采(cai)用同一(yi)PWM信(xin)號對兩(liang)(liang)(liang)級變(bian)換(huan)(huan)(huan)器(qi)(qi)進行聯動控(kong)制。單(dan)端反(fan)激變(bian)換(huan)(huan)(huan)器(qi)(qi)的(de)(de)(de)的(de)(de)(de)占(zhan)空比一(yi)般應(ying)不超過(guo)0.5，以(yi)(yi)減小開關管電壓應(ying)力，而(er)BUCK變(bian)換(huan)(huan)(huan)器(qi)(qi)則希望(wang)盡量提(ti)(ti)高占(zhan)空比，以(yi)(yi)改善輸出電壓波形和動態響應(ying)，因此，在保(bao)證(zheng)能(neng)夠實現所要(yao)求(qiu)的(de)(de)(de)輸出變(bian)化范圍的(de)(de)(de)情況下(xia)，應(ying)盡量提(ti)(ti)高BUCK變(bian)換(huan)(huan)(huan)器(qi)(qi)的(de)(de)(de)占(zhan)空比，這樣(yang)就不能(neng)采(cai)用完全相同的(de)(de)(de)PWM信(xin)號同時控(kong)制兩(liang)(liang)(liang)級變(bian)換(huan)(huan)(huan)器(qi)(qi)。為(wei)(wei)此，本文給出了一(yi)種相對簡單(dan)的(de)(de)(de)控(kong)制策略，使用同一(yi) PWM信(xin)號變(bian)換(huan)(huan)(huan)出占(zhan)空比不同的(de)(de)(de)兩(liang)(liang)(liang)路PWM信(xin)號，分別控(kong)制兩(liang)(liang)(liang)級變(bian)換(huan)(huan)(huan)器(qi)(qi)，具體實現方法(fa)如下(xia)所述。

　　對于任一方波信(xin)(xin)號(hao)，要改(gai)(gai)變(bian)(bian)其(qi)占空(kong)比(bi)（對應(ying)于導(dao)通(tong)時(shi)(shi)(shi)(shi)間，即信(xin)(xin)號(hao)處于高(gao)電(dian)平狀態的時(shi)(shi)(shi)(shi)間），一般有兩種實(shi)現(xian)途徑：一是(shi)改(gai)(gai)變(bian)(bian)其(qi)導(dao)通(tong)時(shi)(shi)(shi)(shi)間而頻(pin)(pin)(pin)率(lv)保(bao)持(chi)不(bu)變(bian)(bian)，二是(shi)改(gai)(gai)變(bian)(bian)其(qi)頻(pin)(pin)(pin)率(lv)而導(dao)通(tong)時(shi)(shi)(shi)(shi)間保(bao)持(chi)不(bu)變(bian)(bian)。本文采用(yong)(yong)后一種途徑，即用(yong)(yong)PWM控(kong)制器(qi)輸出的信(xin)(xin)號(hao)直(zhi)接控(kong)制BUCK變(bian)(bian)換器(qi)，而在保(bao)持(chi)導(dao)通(tong)時(shi)(shi)(shi)(shi)間不(bu)變(bian)(bian)的情況下(xia)將其(qi)信(xin)(xin)號(hao)進(jin)行二分頻(pin)(pin)(pin)，得到占空(kong)比(bi)減半的信(xin)(xin)號(hao)來(lai)控(kong)制單(dan)端反激變(bian)(bian)換器(qi)。具體(ti)實(shi)現(xian)電(dian)路(lu)如圖(tu)2（a）所示，源信(xin)(xin)號(hao)經分頻(pin)(pin)(pin)器(qi)二分頻(pin)(pin)(pin)，得到頻(pin)(pin)(pin)率(lv)減半的信(xin)(xin)號(hao)，再與源信(xin)(xin)號(hao)相(xiang)與，即得到導(dao)通(tong)時(shi)(shi)(shi)(shi)間不(bu)變(bian)(bian)而頻(pin)(pin)(pin)率(lv)減半的信(xin)(xin)號(hao)。電(dian)路(lu)中(zhong)各點波形參見圖(tu)2（b）。

 3 充電控制(zhi)方案

　　近年(nian)來(lai)，如何對電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)高(gao)(gao)效(xiao)、快速地充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)成為充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)技術(shu)研究(jiu)的(de)熱點，國(guo)內外(wai)研究(jiu)人員也提出(chu)了不(bu)少(shao)快速充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)方(fang)法(fa)，本文即參(can)考了其(qi)中(zhong)一種較實用(yong)的(de)慢脈(mo)沖(chong)快速充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)法(fa)，這(zhe)種方(fang)法(fa)能確保在充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)過程中(zhong)及(ji)時消除或降低電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)極(ji)化，電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)析(xi)氣量少(shao)，溫升低，充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)效(xiao)率高(gao)(gao)。整個充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)過程由恒流(liu)和恒壓充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)兩(liang)個階段(duan)組(zu)成，在每一階段(duan)均以(yi)周(zhou)期為幾秒到幾十秒的(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)或電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓脈(mo)沖(chong)進行充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)。而(er)兩(liang)階段(duan)的(de)轉換時刻則由電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)的(de)充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)狀態(tai)所決(jue)定(ding)。

　　由于充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)方法相(xiang)對較復雜，且(qie)需要(yao)對多種(zhong)類(lei)型(xing)和(he)規格的(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)池進(jin)行充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)，故需要(yao)采用(yong)可編程(cheng)器件(jian)進(jin)行控制，而(er)單片機以其相(xiang)對強大的(de)(de)(de)功能(neng)和(he)低廉(lian)的(de)(de)(de)價格成(cheng)為(wei)首選(xuan)。本文選(xuan)用(yong)Motorola公司推(tui)出的(de)(de)(de) MC68HC908GP32作為(wei)主(zhu)控元(yuan)件(jian)，整(zheng)個系(xi)統的(de)(de)(de)組(zu)成(cheng)框(kuang)圖(tu)如圖(tu)3所示，反映電(dian)(dian)(dian)(dian)(dian)池充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)狀(zhuang)態的(de)(de)(de)充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)流、電(dian)(dian)(dian)(dian)(dian)池電(dian)(dian)(dian)(dian)(dian)壓(ya)和(he)溫(wen)度(du)信號經采樣電(dian)(dian)(dian)(dian)(dian)路送入單片機的(de)(de)(de)A/D 轉換口(kou)，單片機根據充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)算法，通過D/A轉換口(kou)輸(shu)出信號控制充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)源的(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)壓(ya)或電(dian)(dian)(dian)(dian)(dian)流給定，從而(er)達(da)到控制充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)源輸(shu)出的(de)(de)(de)目(mu)的(de)(de)(de)。

　　軟件系統采用(yong)模(mo)(mo)(mo)塊(kuai)(kuai)化(hua)設計方法，整個程(cheng)序(xu)由主程(cheng)序(xu)模(mo)(mo)(mo)塊(kuai)(kuai)、各類(lei)電池充電子程(cheng)序(xu)模(mo)(mo)(mo)塊(kuai)(kuai)以及(ji)錯誤處理模(mo)(mo)(mo)塊(kuai)(kuai)組(zu)成，各模(mo)(mo)(mo)塊(kuai)(kuai)相對(dui)獨立(li)，以便于算法改(gai)進及(ji)功(gong)能擴(kuo)充，其中主程(cheng)序(xu)模(mo)(mo)(mo)塊(kuai)(kuai)構架了軟件系統的骨架，通過其對(dui)其他(ta)模(mo)(mo)(mo)塊(kuai)(kuai)的調(diao)用(yong)來(lai)實現完整的充電過程(cheng)控制，其流(liu)程(cheng)圖(tu)見圖(tu)4。

　　為確保充(chong)電(dian)安全(quan)，在開始(shi)充(chong)電(dian)前(qian)檢(jian)測電(dian)池(chi)電(dian)壓(ya)(ya)(ya)和(he)(he)溫度(du)，以(yi)排除電(dian)池(chi)接反、用(yong)戶選擇(ze)的(de)電(dian)池(chi)規(gui)格有(you)誤(wu)等錯(cuo)誤(wu)，并(bing)判斷電(dian)池(chi)的(de)狀態是否適合快速(su)充(chong)電(dian)，如電(dian)池(chi)電(dian)壓(ya)(ya)(ya)或溫度(du)過(guo)低(di)，則(ze)需要進(jin)行(xing)小電(dian)流預充(chong)電(dian)，待電(dian)池(chi)電(dian)壓(ya)(ya)(ya)、溫度(du)達到正常范圍(wei)后再開始(shi)快速(su)充(chong)電(dian)。在整個充(chong)電(dian)過(guo)程中(zhong)均(jun)實時檢(jian)測電(dian)池(chi)電(dian)壓(ya)(ya)(ya)和(he)(he)溫度(du)，并(bing)綜合采(cai)用(yong)最(zui)高(gao)電(dian)壓(ya)(ya)(ya)控(kong)制(zhi)、電(dian)壓(ya)(ya)(ya)零增量控(kong)制(zhi)、最(zui)高(gao)溫度(du)控(kong)制(zhi)和(he)(he)定時控(kong)制(zhi)等方法(fa)來終止快速(su)充(chong)電(dian)，以(yi)確保電(dian)池(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］，對該充電器進行了(le)實(shi)驗(yan)測試，在整個負(fu)載(zai)范圍(wei)內(nei)均有穩定(ding)的(de)輸出(chu)，開關管的(de)最小(xiao)導通時(shi)間(jian)（對應(ying)于(yu)最小(xiao)負(fu)載(zai)）約為1.2us，而(er)開關管（MTP4N80）的(de)開關時(shi)間(jian)和反向(xiang)恢復時(shi)間(jian)之和小(xiao)于(yu)0.7us，故充電電源能穩定(ding)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(yuan)的一(yi)種實(shi)現方法，并充(chong)(chong)分利用了(le)單片機(ji)強大的控制功(gong)(gong)能，絕大部分功(gong)(gong)能由(you)軟(ruan)件編程實(shi)現，使(shi)得系統對硬件的依(yi)賴(lai)性較小，便于(yu)功(gong)(gong)能的擴充(chong)(chong)及(ji)改進。