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)實(shi)(shi)際使(shi)用(yong)(yong)中(zhong)有諸多(duo)不便。本(ben)文設計了一(yi)種通用(yong)(yong)型(xing)的(de)(de)(de)充(chong)(chong)電(dian)(dian)(dian)(dian)器，可對電(dian)(dian)(dian)(dian)壓等(deng)級(ji)為(wei)(wei)1.2V～48V的(de)(de)(de)鎳(nie)鎘、鎳(nie)氫、鉛蓄電(dian)(dian)(dian)(dian)池和鋰(li)電(dian)(dian)(dian)(dian)池進(jin)(jin)行(xing)充(chong)(chong)電(dian)(dian)(dian)(dian)。為(wei)(wei)達到(dao)如(ru)此寬(kuan)的(de)(de)(de)充(chong)(chong)電(dian)(dian)(dian)(dian)范(fan)圍，充(chong)(chong)電(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)源(yuan)采(cai)用(yong)(yong)二(er)級(ji)電(dian)(dian)(dian)(dian)路拓撲，并(bing)使(shi)用(yong)(yong)同一(yi)PWM信號源(yuan)對兩級(ji)電(dian)(dian)(dian)(dian)路進(jin)(jin)行(xing)聯動控(kong)制(zhi)(zhi)。該電(dian)(dian)(dian)(dian)源(yuan)在(zai) 85VAC～265VAC的(de)(de)(de)通用(yong)(yong)輸入范(fan)圍內均可實(shi)(shi)現1.2V（0.3A）～60V（1.6A）的(de)(de)(de)寬(kuan)范(fan)圍輸出(chu)。同時(shi)使(shi)用(yong)(yong)單片機(ji)進(jin)(jin)行(xing)充(chong)(chong)電(dian)(dian)(dian)(dian)控(kong)制(zhi)(zhi)，先進(jin)(jin)的(de)(de)(de)慢(man)脈沖快速充(chong)(chong)電(dian)(dian)(dian)(dian)法(fa)［4］，并(bing)綜合使(shi)用(yong)(yong)定時(shi)控(kong)制(zhi)(zhi)、電(dian)(dian)(dian)(dian)壓控(kong)制(zhi)(zhi)和溫度控(kong)制(zhi)(zhi)來中(zhong)止快速充(chong)(chong)電(dian)(dian)(dian)(dian)，確保不會因過(guo)充(chong)(chong)電(dian)(dian)(dian)(dian)而損(sun)傷電(dian)(dian)(dian)(dian)池。

　　2 充電電源的拓撲結構和控制方案

　　由(you)(you)于要求充(chong)電(dian)電(dian)源的輸(shu)(shu)(shu)出變化范圍為(wei)1.2V（0.3A）～60V（1.6A），采用(yong)單(dan)級(ji)變換器很難(nan)實現這 么大的變化范圍，故(gu)采用(yong)了兩(liang)級(ji)結構(gou)，電(dian)源主電(dian)路如圖(tu)1所(suo)示，交流輸(shu)(shu)(shu)入(ru)經(jing)整(zheng)流濾波得到穩定(ding)的直流電(dian)壓DCin，首先(xian)經(jing)單(dan)端(duan)反激(ji)變換器預穩壓，并實現輸(shu)(shu)(shu)入(ru)級(ji)與(yu)輸(shu)(shu)(shu)出級(ji)的隔離(li)，然后再經(jing)BUCK變換器進一步降壓，得到所(suo)需輸(shu)(shu)(shu)出電(dian)壓。為(wei)了保(bao)證單(dan)端(duan)反激(ji)變換器能穩定(ding)工作(zuo)，加入(ru)了假(jia)負(fu)載R2。由(you)(you)于電(dian)池等效于一個大電(dian)容(rong)，故(gu)輸(shu)(shu)(shu)出端(duan)可不加濾波電(dian)容(rong)。

　　為(wei)簡化控制(zhi)(zhi)，采用(yong)同(tong)(tong)一(yi)(yi)PWM信號(hao)對兩(liang)級(ji)變(bian)(bian)(bian)換(huan)器進行(xing)聯動控制(zhi)(zhi)。單(dan)(dan)端反激(ji)變(bian)(bian)(bian)換(huan)器的(de)的(de)占空比一(yi)(yi)般應不(bu)(bu)超過0.5，以減(jian)小(xiao)開(kai)關管(guan)電(dian)壓(ya)應力，而BUCK變(bian)(bian)(bian)換(huan)器則希(xi)望盡量提高(gao)占空比，以改善輸出(chu)(chu)電(dian)壓(ya)波形(xing)和(he)動態響應，因此，在保證能(neng)夠(gou)實(shi)現所要求的(de)輸出(chu)(chu)變(bian)(bian)(bian)化范圍(wei)的(de)情況下，應盡量提高(gao)BUCK變(bian)(bian)(bian)換(huan)器的(de)占空比，這樣就不(bu)(bu)能(neng)采用(yong)完全相同(tong)(tong)的(de)PWM信號(hao)同(tong)(tong)時控制(zhi)(zhi)兩(liang)級(ji)變(bian)(bian)(bian)換(huan)器。為(wei)此，本文給出(chu)(chu)了一(yi)(yi)種相對簡單(dan)(dan)的(de)控制(zhi)(zhi)策(ce)略(lve)，使用(yong)同(tong)(tong)一(yi)(yi) PWM信號(hao)變(bian)(bian)(bian)換(huan)出(chu)(chu)占空比不(bu)(bu)同(tong)(tong)的(de)兩(liang)路PWM信號(hao)，分別控制(zhi)(zhi)兩(liang)級(ji)變(bian)(bian)(bian)換(huan)器，具體實(shi)現方(fang)法如(ru)下所述。

　　對于(yu)任一(yi)(yi)方波信(xin)(xin)號(hao)(hao)，要改變其(qi)占空比（對應于(yu)導(dao)(dao)通(tong)(tong)時(shi)間(jian)，即(ji)(ji)信(xin)(xin)號(hao)(hao)處于(yu)高電(dian)平狀(zhuang)態的(de)(de)時(shi)間(jian)），一(yi)(yi)般有兩種(zhong)實(shi)現途徑(jing)(jing)：一(yi)(yi)是(shi)改變其(qi)導(dao)(dao)通(tong)(tong)時(shi)間(jian)而(er)(er)頻(pin)率(lv)保(bao)持不(bu)變，二(er)是(shi)改變其(qi)頻(pin)率(lv)而(er)(er)導(dao)(dao)通(tong)(tong)時(shi)間(jian)保(bao)持不(bu)變。本文(wen)采用后一(yi)(yi)種(zhong)途徑(jing)(jing)，即(ji)(ji)用PWM控(kong)制(zhi)器(qi)(qi)輸出(chu)的(de)(de)信(xin)(xin)號(hao)(hao)直接控(kong)制(zhi)BUCK變換器(qi)(qi)，而(er)(er)在保(bao)持導(dao)(dao)通(tong)(tong)時(shi)間(jian)不(bu)變的(de)(de)情況(kuang)下(xia)將其(qi)信(xin)(xin)號(hao)(hao)進行二(er)分頻(pin)，得(de)到占空比減半(ban)的(de)(de)信(xin)(xin)號(hao)(hao)來控(kong)制(zhi)單端反激變換器(qi)(qi)。具體實(shi)現電(dian)路如圖2（a）所(suo)示(shi)，源信(xin)(xin)號(hao)(hao)經分頻(pin)器(qi)(qi)二(er)分頻(pin)，得(de)到頻(pin)率(lv)減半(ban)的(de)(de)信(xin)(xin)號(hao)(hao)，再與(yu)源信(xin)(xin)號(hao)(hao)相(xiang)與(yu)，即(ji)(ji)得(de)到導(dao)(dao)通(tong)(tong)時(shi)間(jian)不(bu)變而(er)(er)頻(pin)率(lv)減半(ban)的(de)(de)信(xin)(xin)號(hao)(hao)。電(dian)路中各(ge)點(dian)波形參(can)見圖2（b）。

 3 充(chong)電(dian)控制方(fang)案(an)

　　近(jin)年來(lai)，如何對電(dian)(dian)(dian)(dian)(dian)池高效、快(kuai)速(su)地充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)成為充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)技術研(yan)究(jiu)的熱點(dian)，國內外(wai)研(yan)究(jiu)人員也提出了不少快(kuai)速(su)充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)方(fang)法(fa)，本文(wen)即參考了其中一(yi)種較(jiao)實(shi)用的慢脈(mo)沖(chong)快(kuai)速(su)充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)法(fa)，這種方(fang)法(fa)能確(que)保在(zai)充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)過(guo)程(cheng)中及(ji)時消除或降(jiang)低電(dian)(dian)(dian)(dian)(dian)池極化，電(dian)(dian)(dian)(dian)(dian)池析(xi)氣(qi)量少，溫升低，充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)效率高。整個充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)過(guo)程(cheng)由恒(heng)流和恒(heng)壓(ya)充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)兩(liang)個階段(duan)組成，在(zai)每(mei)一(yi)階段(duan)均以周期(qi)為幾秒(miao)到(dao)幾十秒(miao)的電(dian)(dian)(dian)(dian)(dian)流或電(dian)(dian)(dian)(dian)(dian)壓(ya)脈(mo)沖(chong)進(jin)行(xing)充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)。而(er)兩(liang)階段(duan)的轉換(huan)時刻(ke)則由電(dian)(dian)(dian)(dian)(dian)池的充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)狀(zhuang)態所決(jue)定。

　　由(you)于充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)方法相對較復雜，且需要(yao)(yao)對多種類型和規格的(de)電(dian)(dian)(dian)(dian)(dian)池(chi)(chi)進行充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)，故需要(yao)(yao)采用(yong)(yong)可(ke)編程器件進行控(kong)制(zhi)，而單(dan)片機(ji)以(yi)其相對強大的(de)功能和低廉的(de)價格成為首選(xuan)。本文選(xuan)用(yong)(yong)Motorola公司推出(chu)的(de) MC68HC908GP32作(zuo)為主控(kong)元件，整個系統的(de)組成框(kuang)圖如(ru)圖3所示，反映(ying)電(dian)(dian)(dian)(dian)(dian)池(chi)(chi)充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)狀(zhuang)態的(de)充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)流、電(dian)(dian)(dian)(dian)(dian)池(chi)(chi)電(dian)(dian)(dian)(dian)(dian)壓(ya)和溫度(du)信(xin)號(hao)經采樣電(dian)(dian)(dian)(dian)(dian)路送入單(dan)片機(ji)的(de)A/D 轉換口，單(dan)片機(ji)根據充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)算法，通過D/A轉換口輸出(chu)信(xin)號(hao)控(kong)制(zhi)充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)源的(de)電(dian)(dian)(dian)(dian)(dian)壓(ya)或電(dian)(dian)(dian)(dian)(dian)流給定(ding)，從而達到控(kong)制(zhi)充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)源輸出(chu)的(de)目的(de)。

　　軟件系統采用(yong)模(mo)塊化設計方法，整個程(cheng)(cheng)序(xu)由(you)主程(cheng)(cheng)序(xu)模(mo)塊、各(ge)類電(dian)池(chi)充(chong)電(dian)子程(cheng)(cheng)序(xu)模(mo)塊以(yi)及錯誤處理模(mo)塊組成，各(ge)模(mo)塊相(xiang)對獨立，以(yi)便于算(suan)法改進及功能(neng)擴充(chong)，其(qi)(qi)中主程(cheng)(cheng)序(xu)模(mo)塊構架了軟件系統的骨架，通過(guo)其(qi)(qi)對其(qi)(qi)他(ta)模(mo)塊的調用(yong)來(lai)實現完整的充(chong)電(dian)過(guo)程(cheng)(cheng)控制，其(qi)(qi)流程(cheng)(cheng)圖(tu)見圖(tu)4。

　　為確保(bao)充(chong)電(dian)(dian)(dian)安(an)全(quan)，在(zai)開始(shi)充(chong)電(dian)(dian)(dian)前(qian)檢測電(dian)(dian)(dian)池(chi)(chi)電(dian)(dian)(dian)壓(ya)和溫度(du)(du)，以排除電(dian)(dian)(dian)池(chi)(chi)接反(fan)、用(yong)戶選擇的電(dian)(dian)(dian)池(chi)(chi)規格有誤等錯(cuo)誤，并判斷(duan)電(dian)(dian)(dian)池(chi)(chi)的狀態是否適合快(kuai)速充(chong)電(dian)(dian)(dian)，如電(dian)(dian)(dian)池(chi)(chi)電(dian)(dian)(dian)壓(ya)或溫度(du)(du)過低，則(ze)需要進(jin)行(xing)小電(dian)(dian)(dian)流預充(chong)電(dian)(dian)(dian)，待(dai)電(dian)(dian)(dian)池(chi)(chi)電(dian)(dian)(dian)壓(ya)、溫度(du)(du)達到正常范(fan)圍后再開始(shi)快(kuai)速充(chong)電(dian)(dian)(dian)。在(zai)整(zheng)個充(chong)電(dian)(dian)(dian)過程中均實時(shi)(shi)檢測電(dian)(dian)(dian)池(chi)(chi)電(dian)(dian)(dian)壓(ya)和溫度(du)(du)，并綜合采用(yong)最高(gao)電(dian)(dian)(dian)壓(ya)控制(zhi)(zhi)、電(dian)(dian)(dian)壓(ya)零增量控制(zhi)(zhi)、最高(gao)溫度(du)(du)控制(zhi)(zhi)和定時(shi)(shi)控制(zhi)(zhi)等方(fang)法來終止快(kuai)速充(chong)電(dian)(dian)(dian)，以確保(bao)電(dian)(dian)(dian)池(chi)(chi)不被過充(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)(zai)范圍內均有穩(wen)定(ding)的輸出，開關管的最小導通時間(jian)（對(dui)應于最小負載(zai)(zai)）約為1.2us，而開關管（MTP4N80）的開關時間(jian)和反向恢復時間(jian)之和小于0.7us，故充電(dian)電(dian)源(yuan)能(neng)穩(wen)定(ding)工作。

　　本文設計了一個通用型智能充電器，給(gei)出(chu)了寬范圍充電(dian)電(dian)源的(de)一種(zhong)實(shi)現方(fang)法(fa)，并充分利用(yong)了單片機(ji)強大(da)的(de)控制功(gong)能，絕大(da)部(bu)分功(gong)能由軟件(jian)編程實(shi)現，使得系統(tong)對硬件(jian)的(de)依賴(lai)性較(jiao)小，便于功(gong)能的(de)擴充及(ji)改進。