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)實(shi)際使(shi)用(yong)中有諸多不便。本文(wen)設計了一種通用(yong)型的(de)充電(dian)(dian)(dian)(dian)(dian)(dian)器，可對電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)等級(ji)(ji)為(wei)1.2V～48V的(de)鎳鎘、鎳氫、鉛蓄電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)和鋰(li)電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)進(jin)(jin)(jin)行充電(dian)(dian)(dian)(dian)(dian)(dian)。為(wei)達到如此(ci)寬的(de)充電(dian)(dian)(dian)(dian)(dian)(dian)范圍，充電(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)源采用(yong)二級(ji)(ji)電(dian)(dian)(dian)(dian)(dian)(dian)路拓撲，并(bing)(bing)使(shi)用(yong)同(tong)一PWM信(xin)號源對兩級(ji)(ji)電(dian)(dian)(dian)(dian)(dian)(dian)路進(jin)(jin)(jin)行聯動控(kong)制(zhi)。該(gai)電(dian)(dian)(dian)(dian)(dian)(dian)源在(zai) 85VAC～265VAC的(de)通用(yong)輸入范圍內均(jun)可實(shi)現1.2V（0.3A）～60V（1.6A）的(de)寬范圍輸出(chu)。同(tong)時(shi)使(shi)用(yong)單片(pian)機(ji)進(jin)(jin)(jin)行充電(dian)(dian)(dian)(dian)(dian)(dian)控(kong)制(zhi)，先進(jin)(jin)(jin)的(de)慢脈沖快速充電(dian)(dian)(dian)(dian)(dian)(dian)法［4］，并(bing)(bing)綜合使(shi)用(yong)定時(shi)控(kong)制(zhi)、電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)控(kong)制(zhi)和溫(wen)度控(kong)制(zhi)來中止(zhi)快速充電(dian)(dian)(dian)(dian)(dian)(dian)，確保不會因(yin)過(guo)充電(dian)(dian)(dian)(dian)(dian)(dian)而(er)損(sun)傷電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)。

　　2 充電電源的拓撲結構和控制方案

　　由于(yu)要求充電(dian)電(dian)源的輸(shu)出(chu)變化(hua)范圍為1.2V（0.3A）～60V（1.6A），采用單級(ji)變換(huan)(huan)器很難實現這(zhe) 么大的變化(hua)范圍，故(gu)采用了兩級(ji)結構，電(dian)源主電(dian)路如(ru)圖(tu)1所(suo)示，交(jiao)流輸(shu)入經整流濾波得到(dao)穩(wen)定的直(zhi)流電(dian)壓(ya)DCin，首先經單端反(fan)激變換(huan)(huan)器預穩(wen)壓(ya)，并實現輸(shu)入級(ji)與輸(shu)出(chu)級(ji)的隔離，然后(hou)再經BUCK變換(huan)(huan)器進一(yi)步降(jiang)壓(ya)，得到(dao)所(suo)需輸(shu)出(chu)電(dian)壓(ya)。為了保證單端反(fan)激變換(huan)(huan)器能穩(wen)定工作，加(jia)入了假負載R2。由于(yu)電(dian)池等效于(yu)一(yi)個大電(dian)容(rong)，故(gu)輸(shu)出(chu)端可不加(jia)濾波電(dian)容(rong)。

　　為簡(jian)化控(kong)制，采用同(tong)(tong)一(yi)PWM信(xin)(xin)號(hao)(hao)對(dui)兩級(ji)變(bian)(bian)換器(qi)(qi)(qi)(qi)進行聯動(dong)控(kong)制。單(dan)端反(fan)激變(bian)(bian)換器(qi)(qi)(qi)(qi)的(de)的(de)占空比(bi)一(yi)般應(ying)(ying)不超過(guo)0.5，以減小開關(guan)管電壓應(ying)(ying)力(li)，而BUCK變(bian)(bian)換器(qi)(qi)(qi)(qi)則希望(wang)盡量(liang)提高占空比(bi)，以改(gai)善輸(shu)出(chu)(chu)電壓波形和動(dong)態響應(ying)(ying)，因此，在保(bao)證能夠實現所要求(qiu)的(de)輸(shu)出(chu)(chu)變(bian)(bian)化范圍的(de)情況下，應(ying)(ying)盡量(liang)提高BUCK變(bian)(bian)換器(qi)(qi)(qi)(qi)的(de)占空比(bi)，這樣就不能采用完(wan)全(quan)相同(tong)(tong)的(de)PWM信(xin)(xin)號(hao)(hao)同(tong)(tong)時控(kong)制兩級(ji)變(bian)(bian)換器(qi)(qi)(qi)(qi)。為此，本文給出(chu)(chu)了一(yi)種相對(dui)簡(jian)單(dan)的(de)控(kong)制策略，使用同(tong)(tong)一(yi) PWM信(xin)(xin)號(hao)(hao)變(bian)(bian)換出(chu)(chu)占空比(bi)不同(tong)(tong)的(de)兩路(lu)PWM信(xin)(xin)號(hao)(hao)，分別(bie)控(kong)制兩級(ji)變(bian)(bian)換器(qi)(qi)(qi)(qi)，具(ju)體實現方法如(ru)下所述。

　　對于任一方波(bo)信號(hao)，要改變(bian)其(qi)占空比(bi)（對應于導(dao)通(tong)時(shi)(shi)(shi)間(jian)，即信號(hao)處于高(gao)電(dian)平(ping)狀(zhuang)態(tai)的(de)(de)(de)(de)時(shi)(shi)(shi)間(jian)），一般有(you)兩(liang)種實現途徑：一是改變(bian)其(qi)導(dao)通(tong)時(shi)(shi)(shi)間(jian)而(er)頻(pin)(pin)率保(bao)持(chi)不(bu)變(bian)，二(er)是改變(bian)其(qi)頻(pin)(pin)率而(er)導(dao)通(tong)時(shi)(shi)(shi)間(jian)保(bao)持(chi)不(bu)變(bian)。本(ben)文(wen)采用后(hou)一種途徑，即用PWM控制器輸出的(de)(de)(de)(de)信號(hao)直接控制BUCK變(bian)換(huan)器，而(er)在(zai)保(bao)持(chi)導(dao)通(tong)時(shi)(shi)(shi)間(jian)不(bu)變(bian)的(de)(de)(de)(de)情況下將其(qi)信號(hao)進(jin)行二(er)分(fen)頻(pin)(pin)，得(de)到占空比(bi)減(jian)半(ban)的(de)(de)(de)(de)信號(hao)來控制單端反激變(bian)換(huan)器。具體實現電(dian)路如圖2（a）所(suo)示，源(yuan)(yuan)信號(hao)經分(fen)頻(pin)(pin)器二(er)分(fen)頻(pin)(pin)，得(de)到頻(pin)(pin)率減(jian)半(ban)的(de)(de)(de)(de)信號(hao)，再(zai)與源(yuan)(yuan)信號(hao)相與，即得(de)到導(dao)通(tong)時(shi)(shi)(shi)間(jian)不(bu)變(bian)而(er)頻(pin)(pin)率減(jian)半(ban)的(de)(de)(de)(de)信號(hao)。電(dian)路中各點波(bo)形參見圖2（b）。

 3 充(chong)電控(kong)制方案(an)

　　近(jin)年來，如何對電(dian)(dian)(dian)(dian)(dian)池高(gao)效、快(kuai)(kuai)速(su)地充(chong)電(dian)(dian)(dian)(dian)(dian)成為(wei)充(chong)電(dian)(dian)(dian)(dian)(dian)技術研(yan)究(jiu)的熱點，國內外研(yan)究(jiu)人(ren)員也提出(chu)了(le)不(bu)少快(kuai)(kuai)速(su)充(chong)電(dian)(dian)(dian)(dian)(dian)方(fang)法(fa)(fa)，本文即參考(kao)了(le)其中一種較實用的慢(man)脈沖(chong)快(kuai)(kuai)速(su)充(chong)電(dian)(dian)(dian)(dian)(dian)法(fa)(fa)，這種方(fang)法(fa)(fa)能確保在(zai)充(chong)電(dian)(dian)(dian)(dian)(dian)過(guo)程中及時(shi)(shi)消除(chu)或降(jiang)低電(dian)(dian)(dian)(dian)(dian)池極化，電(dian)(dian)(dian)(dian)(dian)池析氣量(liang)少，溫升低，充(chong)電(dian)(dian)(dian)(dian)(dian)效率高(gao)。整個充(chong)電(dian)(dian)(dian)(dian)(dian)過(guo)程由恒流(liu)和恒壓充(chong)電(dian)(dian)(dian)(dian)(dian)兩個階段(duan)組成，在(zai)每一階段(duan)均以周期為(wei)幾(ji)秒到幾(ji)十(shi)秒的電(dian)(dian)(dian)(dian)(dian)流(liu)或電(dian)(dian)(dian)(dian)(dian)壓脈沖(chong)進行充(chong)電(dian)(dian)(dian)(dian)(dian)。而兩階段(duan)的轉換時(shi)(shi)刻則(ze)由電(dian)(dian)(dian)(dian)(dian)池的充(chong)電(dian)(dian)(dian)(dian)(dian)狀態(tai)所決定。

　　由于充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)方法相對(dui)較復(fu)雜(za)，且需要對(dui)多(duo)種(zhong)類型和規(gui)格(ge)的(de)電(dian)(dian)(dian)(dian)池進(jin)行(xing)(xing)充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)，故需要采用(yong)可編程器件(jian)進(jin)行(xing)(xing)控制，而(er)單片機(ji)以(yi)其(qi)相對(dui)強大的(de)功能和低廉的(de)價格(ge)成為(wei)(wei)首選(xuan)。本文選(xuan)用(yong)Motorola公司推出的(de) MC68HC908GP32作(zuo)為(wei)(wei)主控元件(jian)，整個系統的(de)組成框圖(tu)如圖(tu)3所示，反映電(dian)(dian)(dian)(dian)池充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)狀態的(de)充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)流(liu)、電(dian)(dian)(dian)(dian)池電(dian)(dian)(dian)(dian)壓(ya)(ya)和溫度信號(hao)經采樣電(dian)(dian)(dian)(dian)路送入單片機(ji)的(de)A/D 轉(zhuan)換口，單片機(ji)根據充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)算(suan)法，通過D/A轉(zhuan)換口輸出信號(hao)控制充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)源的(de)電(dian)(dian)(dian)(dian)壓(ya)(ya)或電(dian)(dian)(dian)(dian)流(liu)給定，從而(er)達到控制充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)源輸出的(de)目的(de)。

　　軟件系統采用模(mo)塊(kuai)化設計方法，整個程(cheng)序由主程(cheng)序模(mo)塊(kuai)、各(ge)類電(dian)池充電(dian)子程(cheng)序模(mo)塊(kuai)以及(ji)錯(cuo)誤處理模(mo)塊(kuai)組成，各(ge)模(mo)塊(kuai)相對(dui)獨立，以便于算法改進(jin)及(ji)功能擴充，其中主程(cheng)序模(mo)塊(kuai)構架(jia)了軟件系統的(de)骨架(jia)，通過(guo)(guo)其對(dui)其他模(mo)塊(kuai)的(de)調用來實現完整的(de)充電(dian)過(guo)(guo)程(cheng)控(kong)制(zhi)，其流程(cheng)圖見圖4。

　　為確保(bao)充(chong)電(dian)(dian)(dian)(dian)安(an)全，在開(kai)始(shi)(shi)充(chong)電(dian)(dian)(dian)(dian)前檢(jian)測電(dian)(dian)(dian)(dian)池(chi)(chi)電(dian)(dian)(dian)(dian)壓(ya)(ya)和溫(wen)度，以(yi)(yi)排除(chu)電(dian)(dian)(dian)(dian)池(chi)(chi)接(jie)反、用戶選擇(ze)的(de)(de)電(dian)(dian)(dian)(dian)池(chi)(chi)規格(ge)有誤等(deng)錯(cuo)誤，并判斷(duan)電(dian)(dian)(dian)(dian)池(chi)(chi)的(de)(de)狀態是否適合快(kuai)速充(chong)電(dian)(dian)(dian)(dian)，如電(dian)(dian)(dian)(dian)池(chi)(chi)電(dian)(dian)(dian)(dian)壓(ya)(ya)或溫(wen)度過(guo)低，則需要進(jin)行(xing)小電(dian)(dian)(dian)(dian)流預充(chong)電(dian)(dian)(dian)(dian)，待電(dian)(dian)(dian)(dian)池(chi)(chi)電(dian)(dian)(dian)(dian)壓(ya)(ya)、溫(wen)度達到正常范圍后再開(kai)始(shi)(shi)快(kuai)速充(chong)電(dian)(dian)(dian)(dian)。在整(zheng)個(ge)充(chong)電(dian)(dian)(dian)(dian)過(guo)程中均實(shi)時檢(jian)測電(dian)(dian)(dian)(dian)池(chi)(chi)電(dian)(dian)(dian)(dian)壓(ya)(ya)和溫(wen)度，并綜(zong)合采(cai)用最高電(dian)(dian)(dian)(dian)壓(ya)(ya)控制、電(dian)(dian)(dian)(dian)壓(ya)(ya)零增量(liang)控制、最高溫(wen)度控制和定時控制等(deng)方(fang)法來終止快(kuai)速充(chong)電(dian)(dian)(dian)(dian)，以(yi)(yi)確保(bao)電(dian)(dian)(dian)(dian)池(chi)(chi)不(bu)被(bei)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(le)實(shi)驗測試，在整個負載范圍(wei)內均有穩定的輸出，開關管的最(zui)小(xiao)導通(tong)時(shi)間(jian)（對應于最(zui)小(xiao)負載）約為1.2us，而(er)開關管（MTP4N80）的開關時(shi)間(jian)和反向(xiang)恢復時(shi)間(jian)之(zhi)和小(xiao)于0.7us，故充(chong)電電源能穩定工作。

　　本文設計了一個通用型智能充電器，給出了寬范圍充電電源(yuan)的(de)一種實現方法，并充分利用了單片機強大的(de)控(kong)制功(gong)能(neng)，絕大部分功(gong)能(neng)由軟件編程(cheng)實現，使得(de)系(xi)統對硬件的(de)依賴性較小(xiao)，便于功(gong)能(neng)的(de)擴充及(ji)改進(jin)。