隨著(zhu)油價(jia)的(de)(de)不(bu)斷上(shang)漲和人(ren)們環保意識的(de)(de)增強(qiang)，電動自行車(che)以其(qi)(qi)(qi)價(jia)格(ge)低、綠色環保，使用(yong)(yong)(yong)安全(quan)方(fang)便(bian)等優點越來越受到消費(fei)者的(de)(de)喜愛(ai)。評(ping)價(jia)電動自行車(che)質量好壞(huai)的(de)(de)重要參數之一是其(qi)(qi)(qi)蓄(xu)電池(chi)(chi)(chi)的(de)(de)使用(yong)(yong)(yong)壽命(ming)(ming)。而蓄(xu)電池(chi)(chi)(chi)的(de)(de)充電過程(cheng)對其(qi)(qi)(qi)壽命(ming)(ming)影響最大。研究表明：過充電，可使蓄(xu)電池(chi)(chi)(chi)發(fa)熱，電解(jie)液失水；而充電不(bu)足，則可使蓄(xu)電池(chi)(chi)(chi)內(nei)化學(xue)反應不(bu)充分，長期充電不(bu)足會(hui)導致蓄(xu)電池(chi)(chi)(chi)容量下降。由此(ci)可見，充電器性能的(de)(de)好壞(huai)直(zhi)接影響著(zhu)蓄(xu)電池(chi)(chi)(chi)的(de)(de)使用(yong)(yong)(yong)效(xiao)果和使用(yong)(yong)(yong)壽命(ming)(ming)。

  目前市場上的充電器存在的主要不足，第一不是從副邊繞組直接獲得取樣信號，因而穩壓效果不理想；第二是輸出電流和電壓調節范圍窄，因而只適用于固定負載。為此，本文介紹了一種以單片機為控制器的通用智能充電器的設計方案。該裝置能(neng)(neng)根(gen)據蓄電(dian)(dian)(dian)池的充(chong)電(dian)(dian)(dian)特性或實時監測到的充(chong)電(dian)(dian)(dian)狀(zhuang)態，來智能(neng)(neng)化地調節(jie)充(chong)電(dian)(dian)(dian)電(dian)(dian)(dian)壓和充(chong)電(dian)(dian)(dian)電(dian)(dian)(dian)流，而且調節(jie)范圍寬，并具有過流、過壓、過溫等保護(hu)功能(neng)(neng)。 1、系統結構 該系統主要由電(dian)(dian)(dian)源(yuan)變(bian)換電(dian)(dian)(dian)路、采(cai)樣電(dian)(dian)(dian)路、微處(chu)理(li)器(qi)，脈寬調制(zhi)器(qi)、鍵盤、顯示器(qi)和溫度傳感器(qi)等部分組成，是(shi)一個閉環的智能(neng)(neng)充(chong)電(dian)(dian)(dian)系統。

   2、硬件電路 本智能充電器的(de)(de)(de)(de)(de)硬件電(dian)(dian)路(lu)(lu)(lu)分(fen)(fen)為(wei)開(kai)關(guan)(guan)電(dian)(dian)源(yuan)部分(fen)(fen)、以單(dan)片機(ji)為(wei)主(zhu)(zhu)的(de)(de)(de)(de)(de)控(kong)(kong)制(zhi)(zhi)電(dian)(dian)路(lu)(lu)(lu)和(he)以UC3842為(wei)核(he)心的(de)(de)(de)(de)(de)脈(mo)寬調(diao)制(zhi)(zhi)電(dian)(dian)路(lu)(lu)(lu)三部分(fen)(fen)。 2．1開(kai)關(guan)(guan)電(dian)(dian)源(yuan)設計(ji) 本設計(ji)采用電(dian)(dian)流(liu)控(kong)(kong)制(zhi)(zhi)型脈(mo)寬調(diao)制(zhi)(zhi)方式(shi)。其整(zheng)個(ge)工作過程是將(jiang)交流(liu)輸入經(jing)濾(lv)波、整(zheng)流(liu)后(hou)(hou)變為(wei)直(zhi)流(liu)高壓(ya)(ya)，再由開(kai)關(guan)(guan)管(guan)斬波、高頻變壓(ya)(ya)器降壓(ya)(ya)后(hou)(hou)得到高頻矩形(xing)電(dian)(dian)壓(ya)(ya)，最后(hou)(hou)經(jing)過輸出整(zheng)流(liu)濾(lv)波獲得所需(xu)要(yao)(yao)的(de)(de)(de)(de)(de)直(zhi)流(liu)輸出電(dian)(dian)壓(ya)(ya)。系(xi)統對開(kai)關(guan)(guan)電(dian)(dian)源(yuan)的(de)(de)(de)(de)(de)要(yao)(yao)求(qiu)是其交流(liu)輸入電(dian)(dian)壓(ya)(ya)范圍為(wei)90～270 V，能(neng)同(tong)時輸出+5V作為(wei)控(kong)(kong)制(zhi)(zhi)部分(fen)(fen)電(dian)(dian)源(yuan)及12～60 V主(zhu)(zhu)回路(lu)(lu)(lu)的(de)(de)(de)(de)(de)電(dian)(dian)壓(ya)(ya)。輸出電(dian)(dian)流(liu)為(wei)1～3 A。 2．2單(dan)片機(ji)控(kong)(kong)制(zhi)(zhi)電(dian)(dian)路(lu)(lu)(lu)設計(ji) 單(dan)片機(ji)控(kong)(kong)制(zhi)(zhi)電(dian)(dian)路(lu)(lu)(lu)主(zhu)(zhu)要(yao)(yao)由單(dan)片機(ji)AT89S52、ADCTLC0832、多路(lu)(lu)(lu)選擇(ze)開(kai)關(guan)(guan)CD4051、數(shu)字電(dian)(dian)位(wei)器X9C102、數(shu)字溫度傳感器DSl8820、取樣電(dian)(dian)阻Rs和(he)Rw、2×4鍵盤、液晶顯示CONl6等組成。

    本(ben)部(bu)分設(she)計(ji)時(shi)應先根據(ju)蓄(xu)(xu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)的(de)(de)(de)型號參(can)數(shu)，來通過(guo)鍵(jian)盤設(she)計(ji)與之對(dui)(dui)應的(de)(de)(de)充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)、充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)以及充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)時(shi)間(jian)，當電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路接上蓄(xu)(xu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)后(hou)(hou)，充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)過(guo)程開(kai)始(shi)，此后(hou)(hou)由單片(pian)(pian)機(ji)(ji)通過(guo)取樣電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)阻RM檢測電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)，若檢測到(dao)(dao)蓄(xu)(xu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)因(yin)過(guo)渡放(fang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)而使電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)低于正常(chang)范(fan)圍。那么(me)，為了避(bi)免充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)過(guo)大(da)(da)而造成蓄(xu)(xu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)損壞，應先對(dui)(dui)蓄(xu)(xu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)實行(xing)(xing)穩定(ding)的(de)(de)(de)小(xiao)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)本(ben)設(she)計(ji)程序中設(she)為l／5的(de)(de)(de)設(she)定(ding)充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)，同時(shi)，單片(pian)(pian)機(ji)(ji)開(kai)始(shi)計(ji)時(shi)，之后(hou)(hou)單片(pian)(pian)機(ji)(ji)將不斷檢測電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)和充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)并顯示在(zai)液晶屏(ping)上，隨著充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)的(de)(de)(de)進(jin)行(xing)(xing)，電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)不斷上升，當上升到(dao)(dao)正常(chang)范(fan)圍時(shi)，單片(pian)(pian)機(ji)(ji)可通過(guo)控制數(shu)字(zi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)位器來調節輸(shu)出(chu)(chu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)，從而轉入大(da)(da)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)恒流(liu)充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)即設(she)定(ding)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)方式，此后(hou)(hou)，單片(pian)(pian)機(ji)(ji)一直保持不停地檢測電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)，當電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)達到(dao)(dao)設(she)定(ding)值(zhi)時(shi)，單片(pian)(pian)機(ji)(ji)發出(chu)(chu)指令，以增大(da)(da)數(shu)字(zi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)位器的(de)(de)(de)阻值(zhi)，并通過(guo)脈(mo)寬調制減小(xiao)輸(shu)出(chu)(chu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)。從而使充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)減小(xiao)，當充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)減小(xiao)到(dao)(dao)1／5的(de)(de)(de)設(she)定(ding)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)時(shi)，再轉為涓流(liu)充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)，最后(hou)(hou)在(zai)充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)時(shi)間(jian)到(dao)(dao)時(shi)關閉電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)，這樣就避(bi)免了因(yin)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)溫升過(guo)快或(huo)嚴重極化而影(ying)響充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)質量，提高蓄(xu)(xu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)的(de)(de)(de)使用(yong)壽命。當檢測到(dao)(dao)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)、充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)和溫度超過(guo)設(she)定(ding)值(zhi)的(de)(de)(de)1／10倍時(shi)由程序設(she)定(ding)，單片(pian)(pian)機(ji)(ji)立(li)即輸(shu)出(chu)(chu)報警信號報警。同時(shi)使繼電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)器動作并切(qie)斷總電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)，以提高充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)的(de)(de)(de)安全性(xing)和可靠性(xing)。

   顯示器(qi)可用(yong)于(yu)顯示單片機(ji)(ji)實時采樣到的蓄電(dian)(dian)(dian)(dian)(dian)池電(dian)(dian)(dian)(dian)(dian)壓、充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)流(liu)、已充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)時間和(he)蓄電(dian)(dian)(dian)(dian)(dian)池的溫度，鍵(jian)盤(pan)則(ze)用(yong)于(yu)設定(ding)充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)壓充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)極限電(dian)(dian)(dian)(dian)(dian)壓、恒流(liu)充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)流(liu)極限充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)流(liu)和(he)充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)時間。電(dian)(dian)(dian)(dian)(dian)路中的單片機(ji)(ji)可通過(guo)串口(kou)RS232和(he)上(shang)位機(ji)(ji)相連(lian)，以用(yong)于(yu)存儲數(shu)據和(he)虛(xu)擬顯示充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)參(can)數(shu)的設定(ding)。當檢測到充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)流(liu)為零(ling)時，單片機(ji)(ji)轉(zhuan)入休眠(mian)狀(zhuang)態。而當檢測到充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)流(liu)不為零(ling)時，單片機(ji)(ji)被激活。

   2．3 PWM控制器設計 PW M控制器部分是以UC3842為核心。UC3842芯片內含有5.0 V基準電壓穩壓器、高增益誤差放大器和脈沖寬度比較器，它可以控制芯片內的驅動器。而驅動器則可提供25 mA的輸出電流．可直接驅動NOSFET調整管，從而調整充電器的輸出電(dian)壓(ya)(ya)(ya)和電(dian)流。由(you)于(yu)該驅動器(qi)同(tong)時具有過流、過壓(ya)(ya)(ya)保護，工作電(dian)源電(dian)壓(ya)(ya)(ya)可以在(zai)8～40 V，而(er)啟(qi)動電(dian)流小(xiao)于(yu)1 mA，工作溫度為O～70℃，因而(er)是目(mu)前較理想的新(xin)型脈寬(kuan)調制(zhi)器(qi)。 PWM控制(zhi)器(qi)在(zai)啟(qi)動時，是由(you)R1、Rw。

   為UC3842提供啟動電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)，待其工(gong)(gong)作后(hou)，其輔助繞組(zu)3、4端的(de)(de)(de)(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)經D1整(zheng)(zheng)流、C4、C5濾(lv)波、DW1穩(wen)壓(ya)(ya)后(hou)得到的(de)(de)(de)(de)(de)(de)16 V直(zhi)流電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)，一路加(jia)到UC38427的(de)(de)(de)(de)(de)(de)7腳為其供電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)，另一路經R3和數字(zi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)位器X9C102分壓(ya)(ya)后(hou)加(jia)到UC3842的(de)(de)(de)(de)(de)(de)2腳。以(yi)作為脈(mo)寬調制的(de)(de)(de)(de)(de)(de)輸入信號。一般在這(zhe)類電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)源的(de)(de)(de)(de)(de)(de)設(she)(she)(she)計中，輸出(chu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)取樣(yang)可與UC3842的(de)(de)(de)(de)(de)(de)供電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)相連。為了反映輸出(chu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)變化，本(ben)設(she)(she)(she)計沒有(you)(you)加(jia)穩(wen)壓(ya)(ya)管，但這(zhe)會(hui)使UC3842的(de)(de)(de)(de)(de)(de)工(gong)(gong)作電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)不(bu)穩(wen)，輸出(chu)諧波成分增(zeng)多，為了克服此不(bu)足，本(ben)設(she)(she)(she)計中UC3842的(de)(de)(de)(de)(de)(de)供電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)采用由3、4繞組(zu)端壓(ya)(ya)單獨整(zheng)(zheng)流、濾(lv)波、穩(wen)壓(ya)(ya)后(hou)，提供給UC3842芯(xin)片16 V的(de)(de)(de)(de)(de)(de)穩(wen)定電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)。充電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)的(de)(de)(de)(de)(de)(de)調節(jie)是將電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)經外環電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)取樣(yang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路R12、RM取樣(yang)，再經多路電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)子開關選(xuan)擇、MD變換，單片機(ji)處理(li)后(hou)，送入數字(zi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)位器，以(yi)控制數字(zi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)位器的(de)(de)(de)(de)(de)(de)有(you)(you)效電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)阻。

   從而間接控制UC3842的2腳電壓，進而控制脈沖占空比，以改變充電電壓。 充電器輸出電(dian)(dian)(dian)(dian)壓(ya)偏高時，反饋回UC3842的2腳電(dian)(dian)(dian)(dian)壓(ya)也升高超過參考電(dian)(dian)(dian)(dian)壓(ya)2.5 V之后，驅(qu)動信(xin)號(hao)的脈沖占空比減小，使輸出電(dian)(dian)(dian)(dian)壓(ya)下降，從而(er)達到(dao)穩壓(ya)的目的。充(chong)電(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)流(liu)的調(diao)(diao)(diao)節(jie)(jie)主(zhu)要是(shi)先將充(chong)電(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)流(liu)經外環電(dian)(dian)(dian)(dian)流(liu)取(qu)樣(yang)電(dian)(dian)(dian)(dian)阻(zu)(zu)Rs取(qu)樣(yang)和(he)LM358放(fang)大可用R1調(diao)(diao)(diao)節(jie)(jie)放(fang)大倍(bei)數(shu)、多路電(dian)(dian)(dian)(dian)子開關選(xuan)擇、MD變換，再送單片機處(chu)理，然后調(diao)(diao)(diao)節(jie)(jie)數(shu)字電(dian)(dian)(dian)(dian)位器的阻(zu)(zu)值。其調(diao)(diao)(diao)節(jie)(jie)過程與電(dian)(dian)(dian)(dian)壓(ya)調(diao)(diao)(diao)節(jie)(jie)相似，實際上(shang)，電(dian)(dian)(dian)(dian)流(liu)調(diao)(diao)(diao)節(jie)(jie)也是(shi)通(tong)過電(dian)(dian)(dian)(dian)壓(ya)調(diao)(diao)(diao)節(jie)(jie)實現(xian)的。

    2．4．保(bao)(bao)護(hu)(hu)(hu)(hu)電(dian)(dian)(dian)(dian)(dian)路設(she)計 當過流(liu)或短路時，內環取樣(yang)電(dian)(dian)(dian)(dian)(dian)阻R10兩(liang)端的電(dian)(dian)(dian)(dian)(dian)壓升(sheng)高。當3腳電(dian)(dian)(dian)(dian)(dian)壓超過1伏(fu)時，通(tong)過UC3842的內部調制(zhi)可使其停止(zhi)脈(mo)(mo)寬(kuan)輸出，開關管截(jie)止(zhi)，輸出電(dian)(dian)(dian)(dian)(dian)壓和(he)電(dian)(dian)(dian)(dian)(dian)流(liu)均為0，從而(er)保(bao)(bao)護(hu)(hu)(hu)(hu)電(dian)(dian)(dian)(dian)(dian)源。過壓時，DW1和(he)DW2會擊(ji)穿(chuan)而(er)短路，也(ye)會造(zao)成(cheng)過流(liu)保(bao)(bao)護(hu)(hu)(hu)(hu)，DW2可用以(yi)保(bao)(bao)護(hu)(hu)(hu)(hu)場效(xiao)應管和(he)UC3842。而(er)當發生欠(qian)(qian)壓時，即當UC3842的7腳電(dian)(dian)(dian)(dian)(dian)壓降至10 V以(yi)下時，UC3842將(jiang)啟動欠(qian)(qian)壓鎖定(ding)電(dian)(dian)(dian)(dian)(dian)路而(er)關閉(bi)開關控制(zhi)器(qi)(qi)。內環的這種反(fan)饋(kui)(kui)調整是(shi)在輸出電(dian)(dian)(dian)(dian)(dian)壓尚未發生變化時，通(tong)過檢測內環電(dian)(dian)(dian)(dian)(dian)流(liu)使脈(mo)(mo)寬(kuan)提前得(de)到(dao)調整，前饋(kui)(kui)控制(zhi)，從而(er)加(jia)快了變換器(qi)(qi)對(dui)異常(chang)情況的動態(tai)響應速度(du)(du)。以(yi)便更加(jia)快速有效(xiao)地起到(dao)保(bao)(bao)護(hu)(hu)(hu)(hu)作用。當然(ran)，外環電(dian)(dian)(dian)(dian)(dian)流(liu)、電(dian)(dian)(dian)(dian)(dian)壓的取樣(yang)Rs、Rw亦(yi)可通(tong)過單(dan)片機的調節作用來(lai)達到(dao)對(dui)異常(chang)情況的保(bao)(bao)護(hu)(hu)(hu)(hu)，但響應速度(du)(du)比內環慢(man)5～10個(ge)工頻周期，因此，外環取樣(yang)主要(yao)是(shi)調節充電(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)流(liu)和(he)充電(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)壓，兼作二(er)次保(bao)(bao)護(hu)(hu)(hu)(hu)，而(er)內環取樣(yang)則是(shi)主要(yao)的，它是(shi)一次的保(bao)(bao)護(hu)(hu)(hu)(hu)，這種雙環保(bao)(bao)護(hu)(hu)(hu)(hu)方式會更加(jia)安(an)全可靠。

    3、軟件設計 在程(cheng)序的(de)初始階(jie)段(duan)，首先是對單片(pian)機進(jin)行初始化，即(ji)根(gen)據(ju)不同(tong)的(de)電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)設定不同(tong)的(de)充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)參數(shu)，選(xuan)擇不同(tong)的(de)充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)策(ce)略。其(qi)后(hou)是判斷(duan)(duan)電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)是否連接正確，根(gen)據(ju)電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)電(dian)(dian)(dian)(dian)(dian)(dian)壓值判斷(duan)(duan)應(ying)該(gai)進(jin)入哪一(yi)個充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)階(jie)段(duan)即(ji)小電(dian)(dian)(dian)(dian)(dian)(dian)流預充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)，大電(dian)(dian)(dian)(dian)(dian)(dian)流恒流充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)或恒壓涓(juan)(juan)流充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)方式(shi)(shi)。在預充(chong)(chong)(chong)階(jie)段(duan)，應(ying)降低充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)壓，而在恒流方式(shi)(shi)時，應(ying)不斷(duan)(duan)檢(jian)測(ce)充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)流是否達到(dao)恒定電(dian)(dian)(dian)(dian)(dian)(dian)流如1.8 A，如果小于1.8 A，則抬(tai)高電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)兩(liang)端的(de)電(dian)(dian)(dian)(dian)(dian)(dian)壓，使之達到(dao)1.8 A，以上(shang)調節(jie)過程(cheng)均可采用(yong)比例控(kong)制(zhi)。在電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)兩(liang)端電(dian)(dian)(dian)(dian)(dian)(dian)壓達到(dao)設定值后(hou)，系(xi)統再進(jin)入涓(juan)(juan)流充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)模式(shi)(shi)。該(gai)充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)器的(de)程(cheng)序流程(cheng)如圖3所示。圖3中，Is為設定的(de)充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)流即(ji)恒流充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)流，Umin為蓄(xu)電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)的(de)放電(dian)(dian)(dian)(dian)(dian)(dian)極限(xian)電(dian)(dian)(dian)(dian)(dian)(dian)壓，Umax為蓄(xu)電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)的(de)充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)極限(xian)電(dian)(dian)(dian)(dian)(dian)(dian)壓。

   應用試驗 本設計選用了電動自行車常用的36 V／12 Ah鉛酸蓄電池作為測試對象，其恒壓充電電壓設定為43 V，恒流充電電流Is為1.8 A，起始時，隨著充電的進行，充電電流幾乎維持1.8 A不變，但電池電壓不斷升高，當充電3小時后。電壓上升減慢；當充電到4小時后，充電電壓接近43 V；之后電壓上升更加緩慢。而且充電下降較快。當充到43 V時，充電器自(zi)動停止。從測(ce)試(shi)數據來(lai)看(kan)，該設計(ji)達到了恒流快充(chong)(chong)(chong)，恒壓涓充(chong)(chong)(chong)，充(chong)(chong)(chong)滿自(zi)行關斷的(de)設計(ji)要求。 5、結(jie)束語 本文設計(ji)的(de)過(guo)度放(fang)電(dian)(dian)預充(chong)(chong)(chong)、恒流快充(chong)(chong)(chong)、恒壓涓充(chong)(chong)(chong)、智能控制(zhi)的(de)充(chong)(chong)(chong)電(dian)(dian)方(fang)案(an)，能很好地解決(jue)電(dian)(dian)動自(zi)行車用(yong)電(dian)(dian)池在充(chong)(chong)(chong)電(dian)(dian)過(guo)程中存在的(de)過(guo)充(chong)(chong)(chong)電(dian)(dian)、充(chong)(chong)(chong)電(dian)(dian)不(bu)足和(he)發熱等(deng)問(wen)題，并能根(gen)據不(bu)同電(dian)(dian)池選擇不(bu)同的(de)充(chong)(chong)(chong)電(dian)(dian)方(fang)案(an)。而且具(ju)有通用(yong)性。能實時檢測(ce)并顯示充(chong)(chong)(chong)電(dian)(dian)電(dian)(dian)流、充(chong)(chong)(chong)電(dian)(dian)電(dian)(dian)壓、充(chong)(chong)(chong)電(dian)(dian)時間和(he)蓄電(dian)(dian)池溫度等(deng)參數。由于電(dian)(dian)路具(ju)有內(nei)外環控制(zhi)，符合最優(you)控制(zhi)規律。最具(ju)有過(guo)流、過(guo)壓和(he)超溫保護功能，同時由于

   UC3842采用穩壓供電(dian)，因此，不但諧波污染程度(du)低，原副邊(bian)電(dian)氣(qi)隔離(li)安全可(ke)靠，同時(shi)還可(ke)根(gen)據負載情況通過單(dan)片機來進(jin)行(xing)控制，并可(ke)實現跳周期(qi)模式工作。故(gu)可(ke)提高電(dian)源的效率。