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，這在實際使用(yong)(yong)中有諸多不(bu)便。本文設(she)計了一(yi)種通(tong)用(yong)(yong)型(xing)的(de)充(chong)電(dian)(dian)(dian)器(qi)，可對電(dian)(dian)(dian)壓等(deng)級(ji)為1.2V～48V的(de)鎳(nie)鎘、鎳(nie)氫、鉛蓄電(dian)(dian)(dian)池(chi)(chi)和(he)鋰電(dian)(dian)(dian)池(chi)(chi)進行充(chong)電(dian)(dian)(dian)。為達到如此寬的(de)充(chong)電(dian)(dian)(dian)范圍(wei)，充(chong)電(dian)(dian)(dian)電(dian)(dian)(dian)源采(cai)用(yong)(yong)二級(ji)電(dian)(dian)(dian)路拓撲，并(bing)使用(yong)(yong)同一(yi)PWM信號(hao)源對兩級(ji)電(dian)(dian)(dian)路進行聯動控(kong)(kong)制。該電(dian)(dian)(dian)源在 85VAC～265VAC的(de)通(tong)用(yong)(yong)輸入范圍(wei)內均(jun)可實現1.2V（0.3A）～60V（1.6A）的(de)寬范圍(wei)輸出。同時(shi)使用(yong)(yong)單(dan)片(pian)機進行充(chong)電(dian)(dian)(dian)控(kong)(kong)制，先進的(de)慢脈沖(chong)快速充(chong)電(dian)(dian)(dian)法［4］，并(bing)綜合使用(yong)(yong)定(ding)時(shi)控(kong)(kong)制、電(dian)(dian)(dian)壓控(kong)(kong)制和(he)溫度控(kong)(kong)制來中止快速充(chong)電(dian)(dian)(dian)，確保不(bu)會因過(guo)充(chong)電(dian)(dian)(dian)而損(sun)傷電(dian)(dian)(dian)池(chi)(chi)。

　　2 充電電源的拓撲結構和控制方案

　　由(you)于要求充電(dian)電(dian)源的(de)輸(shu)出(chu)(chu)變(bian)化范圍為(wei)1.2V（0.3A）～60V（1.6A），采(cai)用(yong)單(dan)級變(bian)換(huan)器(qi)很難實(shi)現這 么(me)大(da)的(de)變(bian)化范圍，故采(cai)用(yong)了兩(liang)級結構，電(dian)源主(zhu)電(dian)路如圖(tu)1所示，交流輸(shu)入(ru)(ru)經整流濾波(bo)(bo)得到穩(wen)(wen)定的(de)直流電(dian)壓DCin，首先經單(dan)端反激變(bian)換(huan)器(qi)預(yu)穩(wen)(wen)壓，并實(shi)現輸(shu)入(ru)(ru)級與輸(shu)出(chu)(chu)級的(de)隔(ge)離(li)，然后再(zai)經BUCK變(bian)換(huan)器(qi)進(jin)一步降壓，得到所需輸(shu)出(chu)(chu)電(dian)壓。為(wei)了保(bao)證單(dan)端反激變(bian)換(huan)器(qi)能穩(wen)(wen)定工作，加入(ru)(ru)了假負(fu)載R2。由(you)于電(dian)池等效于一個(ge)大(da)電(dian)容(rong)，故輸(shu)出(chu)(chu)端可不加濾波(bo)(bo)電(dian)容(rong)。

　　為(wei)簡化(hua)控(kong)(kong)制(zhi)，采用同一PWM信號對(dui)兩級(ji)變(bian)換(huan)器(qi)進行聯動控(kong)(kong)制(zhi)。單端反(fan)激變(bian)換(huan)器(qi)的(de)的(de)占(zhan)(zhan)空(kong)比一般應(ying)(ying)不超過(guo)0.5，以(yi)減小開關管電壓應(ying)(ying)力，而BUCK變(bian)換(huan)器(qi)則希望盡量提高占(zhan)(zhan)空(kong)比，以(yi)改善輸出(chu)電壓波形和動態響應(ying)(ying)，因此，在(zai)保證能(neng)夠實現(xian)所(suo)要求的(de)輸出(chu)變(bian)化(hua)范圍的(de)情況下，應(ying)(ying)盡量提高BUCK變(bian)換(huan)器(qi)的(de)占(zhan)(zhan)空(kong)比，這(zhe)樣就不能(neng)采用完全相(xiang)同的(de)PWM信號同時控(kong)(kong)制(zhi)兩級(ji)變(bian)換(huan)器(qi)。為(wei)此，本文給出(chu)了(le)一種相(xiang)對(dui)簡單的(de)控(kong)(kong)制(zhi)策略，使用同一 PWM信號變(bian)換(huan)出(chu)占(zhan)(zhan)空(kong)比不同的(de)兩路PWM信號，分別控(kong)(kong)制(zhi)兩級(ji)變(bian)換(huan)器(qi)，具(ju)體實現(xian)方法如下所(suo)述(shu)。

　　對(dui)于(yu)任一方波信號(hao)，要改變其(qi)(qi)占(zhan)(zhan)空比（對(dui)應于(yu)導(dao)通(tong)(tong)(tong)時(shi)間，即信號(hao)處(chu)于(yu)高電平狀態的(de)時(shi)間），一般有(you)兩種實現途徑(jing)：一是改變其(qi)(qi)導(dao)通(tong)(tong)(tong)時(shi)間而(er)頻(pin)(pin)率(lv)保(bao)持(chi)(chi)不變，二是改變其(qi)(qi)頻(pin)(pin)率(lv)而(er)導(dao)通(tong)(tong)(tong)時(shi)間保(bao)持(chi)(chi)不變。本文采用后一種途徑(jing)，即用PWM控(kong)制(zhi)器(qi)輸(shu)出(chu)的(de)信號(hao)直接(jie)控(kong)制(zhi)BUCK變換器(qi)，而(er)在保(bao)持(chi)(chi)導(dao)通(tong)(tong)(tong)時(shi)間不變的(de)情況下將(jiang)其(qi)(qi)信號(hao)進行二分(fen)頻(pin)(pin)，得(de)到(dao)占(zhan)(zhan)空比減(jian)半(ban)(ban)(ban)的(de)信號(hao)來控(kong)制(zhi)單端反(fan)激(ji)變換器(qi)。具體實現電路如(ru)圖(tu)2（a）所示，源信號(hao)經分(fen)頻(pin)(pin)器(qi)二分(fen)頻(pin)(pin)，得(de)到(dao)頻(pin)(pin)率(lv)減(jian)半(ban)(ban)(ban)的(de)信號(hao)，再與源信號(hao)相與，即得(de)到(dao)導(dao)通(tong)(tong)(tong)時(shi)間不變而(er)頻(pin)(pin)率(lv)減(jian)半(ban)(ban)(ban)的(de)信號(hao)。電路中各點波形參(can)見圖(tu)2（b）。

 3 充電控制方(fang)案

　　近年來，如何對(dui)電(dian)(dian)(dian)(dian)(dian)池高效、快速地(di)充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)成(cheng)為(wei)充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)技術研究的(de)(de)(de)熱點(dian)，國內(nei)外(wai)研究人員也(ye)提出了不少快速充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)方(fang)法(fa)，本文即(ji)參考了其中(zhong)一(yi)種較(jiao)實用的(de)(de)(de)慢脈沖快速充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)法(fa)，這(zhe)種方(fang)法(fa)能確保(bao)在(zai)充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)過程(cheng)中(zhong)及時消除或(huo)降低電(dian)(dian)(dian)(dian)(dian)池極化，電(dian)(dian)(dian)(dian)(dian)池析氣量少，溫升低，充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)效率高。整(zheng)個充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)過程(cheng)由恒流和恒壓充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)兩個階(jie)段(duan)組成(cheng)，在(zai)每一(yi)階(jie)段(duan)均以周期為(wei)幾秒(miao)到幾十秒(miao)的(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)流或(huo)電(dian)(dian)(dian)(dian)(dian)壓脈沖進行充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)。而兩階(jie)段(duan)的(de)(de)(de)轉換(huan)時刻則由電(dian)(dian)(dian)(dian)(dian)池的(de)(de)(de)充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)狀態所決定。

　　由(you)于充(chong)電(dian)(dian)(dian)(dian)(dian)方法相(xiang)對(dui)較復雜，且(qie)需要對(dui)多(duo)種類(lei)型和(he)規格(ge)的(de)(de)電(dian)(dian)(dian)(dian)(dian)池進(jin)行充(chong)電(dian)(dian)(dian)(dian)(dian)，故需要采用可編程器件(jian)進(jin)行控(kong)制，而單片(pian)機以其相(xiang)對(dui)強大的(de)(de)功(gong)能和(he)低廉的(de)(de)價(jia)格(ge)成(cheng)為首選。本文選用Motorola公司推出的(de)(de) MC68HC908GP32作為主控(kong)元件(jian)，整(zheng)個系(xi)統的(de)(de)組成(cheng)框圖(tu)如(ru)圖(tu)3所(suo)示，反(fan)映(ying)電(dian)(dian)(dian)(dian)(dian)池充(chong)電(dian)(dian)(dian)(dian)(dian)狀態的(de)(de)充(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(pian)機的(de)(de)A/D 轉換口，單片(pian)機根據充(chong)電(dian)(dian)(dian)(dian)(dian)算法，通過D/A轉換口輸出信號控(kong)制充(chong)電(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)源(yuan)的(de)(de)電(dian)(dian)(dian)(dian)(dian)壓(ya)或(huo)電(dian)(dian)(dian)(dian)(dian)流給(gei)定，從而達(da)到控(kong)制充(chong)電(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)源(yuan)輸出的(de)(de)目的(de)(de)。

　　軟件系(xi)統采(cai)用模(mo)(mo)塊(kuai)(kuai)(kuai)化設計方法，整個程(cheng)序(xu)由(you)主(zhu)程(cheng)序(xu)模(mo)(mo)塊(kuai)(kuai)(kuai)、各類電(dian)(dian)池充電(dian)(dian)子(zi)程(cheng)序(xu)模(mo)(mo)塊(kuai)(kuai)(kuai)以及錯誤(wu)處理模(mo)(mo)塊(kuai)(kuai)(kuai)組成，各模(mo)(mo)塊(kuai)(kuai)(kuai)相對獨立，以便于(yu)算法改進及功能擴充，其(qi)中主(zhu)程(cheng)序(xu)模(mo)(mo)塊(kuai)(kuai)(kuai)構架了(le)軟件系(xi)統的骨架，通過其(qi)對其(qi)他模(mo)(mo)塊(kuai)(kuai)(kuai)的調(diao)用來(lai)實現完整的充電(dian)(dian)過程(cheng)控制(zhi)，其(qi)流程(cheng)圖見圖4。

　　為確保(bao)充(chong)電(dian)(dian)(dian)安全，在開始充(chong)電(dian)(dian)(dian)前檢(jian)測電(dian)(dian)(dian)池(chi)電(dian)(dian)(dian)壓和(he)(he)溫度，以排(pai)除電(dian)(dian)(dian)池(chi)接反、用戶(hu)選(xuan)擇的電(dian)(dian)(dian)池(chi)規(gui)格有誤(wu)等錯誤(wu)，并(bing)判斷電(dian)(dian)(dian)池(chi)的狀(zhuang)態是否適合快(kuai)速(su)(su)充(chong)電(dian)(dian)(dian)，如電(dian)(dian)(dian)池(chi)電(dian)(dian)(dian)壓或溫度過(guo)低，則(ze)需要進行小電(dian)(dian)(dian)流(liu)預(yu)充(chong)電(dian)(dian)(dian)，待電(dian)(dian)(dian)池(chi)電(dian)(dian)(dian)壓、溫度達到正常(chang)范圍后再開始快(kuai)速(su)(su)充(chong)電(dian)(dian)(dian)。在整個充(chong)電(dian)(dian)(dian)過(guo)程(cheng)中均(jun)實時(shi)檢(jian)測電(dian)(dian)(dian)池(chi)電(dian)(dian)(dian)壓和(he)(he)溫度，并(bing)綜合采用最高(gao)電(dian)(dian)(dian)壓控制(zhi)、電(dian)(dian)(dian)壓零增量控制(zhi)、最高(gao)溫度控制(zhi)和(he)(he)定時(shi)控制(zhi)等方法來終(zhong)止快(kuai)速(su)(su)充(chong)電(dian)(dian)(dian)，以確保(bao)電(dian)(dian)(dian)池(chi)不被(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］，對該充電器進行了實驗測試，在整個(ge)負載(zai)范圍內均有穩(wen)定的(de)輸出，開(kai)關(guan)管的(de)最小(xiao)(xiao)導通(tong)時間（對應于(yu)最小(xiao)(xiao)負載(zai)）約(yue)為1.2us，而開(kai)關(guan)管（MTP4N80）的(de)開(kai)關(guan)時間和(he)反向恢復時間之(zhi)和(he)小(xiao)(xiao)于(yu)0.7us，故充電電源能穩(wen)定工(gong)作。

　　本文設計了一個通用型智能充電器，給出了(le)寬范圍充電電源的(de)(de)一種實(shi)現(xian)方法(fa)，并充分利用(yong)了(le)單(dan)片機強(qiang)大的(de)(de)控制功(gong)能(neng)，絕(jue)大部分功(gong)能(neng)由(you)軟(ruan)件編程實(shi)現(xian)，使得系(xi)統對硬件的(de)(de)依賴性較小，便(bian)于功(gong)能(neng)的(de)(de)擴充及改(gai)進。