近年(nian)來隨著(zhu)能(neng)(neng)源短缺問題日益突(tu)出， 太陽(yang)(yang)能(neng)(neng)、風能(neng)(neng)等新型無污染的替代能(neng)(neng)源應用日益受到重視。獨立型太陽(yang)(yang)能(neng)(neng)照明系統因(yin)其結構簡單、無需鋪設(she)電纜， 且搭建、攜(xie)帶(dai)較為方便等特點在照明領(ling)域有著(zhu)廣泛應用前景(jing)。

　　但(dan)(dan)目前急需解決的(de)有鉛(qian)酸(suan)蓄(xu)電(dian)(dian)池(chi)使用(yong)壽(shou)命(ming)(ming)較短及系統(tong)(tong)(tong)在弱(ruo)(ruo)光(guang)條(tiao)件(jian)下充(chong)電(dian)(dian)能(neng)(neng)力(li)不足這兩(liang)大問題(ti)。系統(tong)(tong)(tong)儲(chu)能(neng)(neng)元件(jian)鉛(qian)酸(suan)蓄(xu)電(dian)(dian)池(chi)設(she)計壽(shou)命(ming)(ming)約三年， 但(dan)(dan)由于(yu)充(chong)電(dian)(dian)方式、存(cun)儲(chu)方式以及人為等(deng)(deng)諸多因素的(de)影(ying)響(xiang)導致(zhi)其使用(yong)壽(shou)命(ming)(ming)過(guo)短，需要(yao)經常更換， 不僅加大了使用(yong)成(cheng)本也影(ying)響(xiang)了系統(tong)(tong)(tong)的(de)穩定性。另外(wai)(wai)大部分已使用(yong)的(de)系統(tong)(tong)(tong)在弱(ruo)(ruo)光(guang)條(tiao)件(jian)下充(chong)電(dian)(dian)能(neng)(neng)力(li)不足， 導致(zhi)系統(tong)(tong)(tong)太陽能(neng)(neng)板利用(yong)率(lv)不高； 傳統(tong)(tong)(tong)提高弱(ruo)(ruo)光(guang)充(chong)電(dian)(dian)能(neng)(neng)力(li)的(de)方法是采(cai)用(yong)組(zu)態(tai)優化控制來(lai)實(shi)現， 即根據外(wai)(wai)界(jie)光(guang)照(zhao)強(qiang)弱(ruo)(ruo)采(cai)用(yong)繼電(dian)(dian)器(qi)控制太陽能(neng)(neng)板組(zu)件(jian)按照(zhao)串聯(lian)或并(bing)聯(lian)等(deng)(deng)不同的(de)組(zu)合(he)方式給蓄(xu)電(dian)(dian)池(chi)充(chong)電(dian)(dian)， 確保(bao)太陽能(neng)(neng)板組(zu)件(jian)輸(shu)出電(dian)(dian)壓始終達到設(she)定充(chong)電(dian)(dian)電(dian)(dian)壓。這種方法雖(sui)然(ran)可以實(shi)現弱(ruo)(ruo)光(guang)充(chong)電(dian)(dian)， 但(dan)(dan)在組(zu)態(tai)變化的(de)瞬(shun)間(jian)， 電(dian)(dian)路輸(shu)出電(dian)(dian)壓波(bo)動較大， 影(ying)響(xiang)系統(tong)(tong)(tong)穩定性。此(ci)外(wai)(wai)， 由于(yu)采(cai)用(yong)繼電(dian)(dian)器(qi)控制， 繼電(dian)(dian)器(qi)的(de)機械開關觸點在工作(zuo)(zuo)較長時間(jian)后容(rong)易磨損失(shi)靈甚至引起誤操(cao)作(zuo)(zuo)。為了有效提高系統(tong)(tong)(tong)弱(ruo)(ruo)光(guang)充(chong)電(dian)(dian)能(neng)(neng)力(li)， 本文采(cai)用(yong)超級電(dian)(dian)容(rong)器(qi)組(zu)及升降壓電(dian)(dian)路來(lai)實(shi)現弱(ruo)(ruo)光(guang)條(tiao)件(jian)下有效充(chong)電(dian)(dian)， 并(bing)采(cai)用(yong)UC3909 實(shi)現對(dui)膠體密封(feng)鉛(qian)酸(suan)蓄(xu)電(dian)(dian)池(chi)智(zhi)能(neng)(neng)化充(chong)電(dian)(dian)管理， 延長蓄(xu)電(dian)(dian)池(chi)使用(yong)壽(shou)命(ming)(ming)。

　　1  鉛酸蓄電池充電特性

　　鉛酸蓄(xu)電(dian)(dian)池的充(chong)電(dian)(dian)特(te)性(xing)是(shi)由(you)其(qi)最(zui)大接(jie)受充(chong)電(dian)(dian)能力來體現， 是(shi)在(zai)保(bao)證蓄(xu)電(dian)(dian)池析氣率(lv)較低、溫升較低時(shi)所能承受的最(zui)大充(chong)電(dian)(dian)電(dian)(dian)流。其(qi)充(chong)電(dian)(dian)特(te)性(xing)曲(qu)線方程式(shi)為：

       式(shi)中， I 為充(chong)(chong)電電流； I 0為初(chu)始最大充(chong)(chong)電電流； a 為最大接受(shou)力比(bi)； t 為充(chong)(chong)電時間(jian)。

　　在實際的(de)電(dian)(dian)池(chi)充(chong)電(dian)(dian)管理(li)(li)過程中， 要使蓄(xu)電(dian)(dian)池(chi)的(de)充(chong)電(dian)(dian)過程完全(quan)吻(wen)合該充(chong)電(dian)(dian)特(te)性(xing)(xing)曲線(xian)(xian)存在較大困難。因此本著提高充(chong)電(dian)(dian)效(xiao)(xiao)率(lv)、保(bao)障蓄(xu)電(dian)(dian)池(chi)使用壽命、實現合理(li)(li)有效(xiao)(xiao)充(chong)電(dian)(dian)的(de)原則，           參(can)考充(chong)電(dian)(dian)特(te)性(xing)(xing)曲線(xian)(xian)， 采用智能控制芯片UC3909 實現對膠體密封鉛酸(suan)蓄(xu)電(dian)(dian)池(chi)分段充(chong)放(fang)電(dian)(dian)控制管理(li)(li)。

　　2  基于UC3909 控制器的四階段充電

　　目前獨立型太陽(yang)能(neng)照明系(xi)統中蓄(xu)(xu)電(dian)(dian)(dian)(dian)池(chi)(chi)充(chong)(chong)電(dian)(dian)(dian)(dian)控制器(qi)一般采用(yong)的(de)是三階段充(chong)(chong)電(dian)(dian)(dian)(dian)方式(shi)(shi)，即(ji)先恒(heng)流(liu)充(chong)(chong)電(dian)(dian)(dian)(dian)、再(zai)恒(heng)壓(ya)充(chong)(chong)電(dian)(dian)(dian)(dian)、后(hou)浮(fu)充(chong)(chong)充(chong)(chong)電(dian)(dian)(dian)(dian)。但由(you)于某些(xie)應用(yong)場合(he)的(de)蓄(xu)(xu)電(dian)(dian)(dian)(dian)池(chi)(chi)會(hui)經常(chang)出現過(guo)度放電(dian)(dian)(dian)(dian)的(de)情況， 如果一開始就(jiu)直接進入(ru)較大電(dian)(dian)(dian)(dian)流(liu)充(chong)(chong)電(dian)(dian)(dian)(dian)的(de)恒(heng)流(liu)充(chong)(chong)電(dian)(dian)(dian)(dian)階段， 容(rong)易造成熱失控， 易損壞蓄(xu)(xu)電(dian)(dian)(dian)(dian)池(chi)(chi)。所(suo)以(yi)在最(zui)開始的(de)時(shi)候應該采用(yong)小電(dian)(dian)(dian)(dian)流(liu)IT 充(chong)(chong)電(dian)(dian)(dian)(dian)的(de)涓(juan)流(liu)充(chong)(chong)電(dian)(dian)(dian)(dian)模式(shi)(shi)， 等蓄(xu)(xu)電(dian)(dian)(dian)(dian)池(chi)(chi)的(de)端電(dian)(dian)(dian)(dian)壓(ya)達(da)到設定的(de)充(chong)(chong)電(dian)(dian)(dian)(dian)使能(neng)電(dian)(dian)(dian)(dian)壓(ya)UT 時(shi)， 再(zai)進行恒(heng)流(liu)充(chong)(chong)電(dian)(dian)(dian)(dian)。UC3909 芯片可(ke)以(yi)根據(ju)蓄(xu)(xu)電(dian)(dian)(dian)(dian)池(chi)(chi)的(de)狀態實現涓(juan)流(liu)充(chong)(chong)電(dian)(dian)(dian)(dian)、恒(heng)流(liu)充(chong)(chong)電(dian)(dian)(dian)(dian)、恒(heng)壓(ya)充(chong)(chong)電(dian)(dian)(dian)(dian)和(he)浮(fu)充(chong)(chong)充(chong)(chong)電(dian)(dian)(dian)(dian)四個階段合(he)理(li)充(chong)(chong)電(dian)(dian)(dian)(dian)， 如圖1 所(suo)示。

                                                                                         圖1  UC3909 的四(si)階段(duan)充電曲線

　　狀態1: 涓流充電。

　　當蓄電池電壓低于充電使能電壓UT , 充電器提供很小的涓流IT 進行(xing)充(chong)電(dian)， IT 一般(ban)約為0. 01C（ C 為蓄電(dian)池容量）狀態(tai)2: 恒流充(chong)電(dian)。

　　當蓄(xu)(xu)(xu)電(dian)(dian)池(chi)(chi)的(de)(de)電(dian)(dian)壓達到充電(dian)(dian)使(shi)能電(dian)(dian)壓UT 時， 充電(dian)(dian)器提供一個大電(dian)(dian)流(liu)I BULK 對蓄(xu)(xu)(xu)電(dian)(dian)池(chi)(chi)進(jin)行恒(heng)流(liu)充電(dian)(dian)， 這(zhe)一階段是(shi)充電(dian)(dian)的(de)(de)主要階段， 蓄(xu)(xu)(xu)電(dian)(dian)池(chi)(chi)端(duan)電(dian)(dian)壓上(shang)(shang)升很快， 直至(zhi)電(dian)(dian)壓上(shang)(shang)升到過壓充電(dian)(dian)電(dian)(dian)壓UOC 時進(jin)入恒(heng)壓充電(dian)(dian)階段。

　　狀態3: 恒壓充電。

　　在此階段(duan)， 充(chong)電(dian)(dian)(dian)器提供一個(ge)略高于蓄(xu)電(dian)(dian)(dian)池額定值的電(dian)(dian)(dian)壓(ya)UOC進行恒壓(ya)充(chong)電(dian)(dian)(dian)， 電(dian)(dian)(dian)路的充(chong)電(dian)(dian)(dian)電(dian)(dian)(dian)流將按(an)指數規律逐漸(jian)減小， 直至電(dian)(dian)(dian)流大(da)小等于充(chong)電(dian)(dian)(dian)終止電(dian)(dian)(dian)流I OCT（約為(wei)10 % IBULK ） , 蓄(xu)電(dian)(dian)(dian)池已被充(chong)滿， 充(chong)電(dian)(dian)(dian)器進入浮充(chong)充(chong)電(dian)(dian)(dian)狀態(tai)。

　　狀態4: 浮充充電。

　　浮(fu)充(chong)充(chong)電(dian)(dian)階段(duan)， 充(chong)電(dian)(dian)器提供浮(fu)充(chong)電(dian)(dian)壓(ya)(ya)UF 對蓄電(dian)(dian)池以(yi)很小(xiao)的浮(fu)充(chong)電(dian)(dian)流進(jin)行充(chong)電(dian)(dian)， 以(yi)彌補(bu)蓄電(dian)(dian)池自放電(dian)(dian)造成的容量損(sun)失。同時(shi)由(you)于蓄電(dian)(dian)池的浮(fu)充(chong)電(dian)(dian)壓(ya)(ya)隨溫(wen)度(du)變(bian)化(hua)而變(bian)化(hua)， 因此需要(yao)選擇與(yu)蓄電(dian)(dian)池相同溫(wen)度(du)系(xi)(xi)數的熱敏電(dian)(dian)阻(zu)進(jin)行溫(wen)度(du)補(bu)償(chang)， 確保(bao)在任(ren)何溫(wen)度(du)下都(dou)能(neng)以(yi)精確的浮(fu)充(chong)電(dian)(dian)壓(ya)(ya)進(jin)行浮(fu)充(chong)充(chong)電(dian)(dian)。溫(wen)度(du)系(xi)(xi)數一般(ban)選擇- 3. 5~ - 5 mV/ .

　　3  充電電路設計

　　圖2 所示為基于U C3909 太陽能蓄電池充電器電(dian)(dian)路框圖， 光伏陣列(lie)經過(guo)電(dian)(dian)壓電(dian)(dian)流采樣再經模數轉(zhuan)換(huan)將(jiang)數字信號反饋至單(dan)片(pian)機， 單(dan)片(pian)機根據光伏陣列(lie)的(de)工作(zuo)狀況輸出PWM 信號去驅動(dong)PMOS 管(guan)， 實(shi)現對(dui)光伏陣列(lie)的(de)最大功率跟蹤(zong)。超(chao)(chao)級(ji)電(dian)(dian)容(rong)器(qi)組、DC/ DC 變(bian)換(huan)器(qi)、UC3909 用來實(shi)現對(dui)閥控鉛酸蓄電(dian)(dian)池(chi)(chi)的(de)四(si)階段(duan)充(chong)電(dian)(dian)控制， 并(bing)利(li)用超(chao)(chao)級(ji)電(dian)(dian)容(rong)的(de)特性優化充(chong)放電(dian)(dian)過(guo)程。本文側(ce)重對(dui)超(chao)(chao)級(ji)電(dian)(dian)容(rong)器(qi)組、U C3909 及DC/ DC 變(bian)換(huan)器(qi)等(deng)部分實(shi)現對(dui)閥控鉛酸蓄電(dian)(dian)池(chi)(chi)四(si)階段(duan)的(de)充(chong)電(dian)(dian)分析及設計。

圖(tu)2  系統框圖(tu)

　　3. 1  UC3909 充電器主要參數(shu)設計

　　基于(yu)UC3909 的充放電電路如圖3 所示。

      圖3  基于UC3909的充(chong)放電電路

　　根(gen)(gen)據UC3909 內部(bu)集成電(dian)(dian)(dian)(dian)路(lu)及光伏陣列、超(chao)級電(dian)(dian)(dian)(dian)容參(can)數并結合閥(fa)控鉛(qian)酸蓄電(dian)(dian)(dian)(dian)池(chi)(chi)的(de)容量及額定電(dian)(dian)(dian)(dian)壓(ya)等參(can)數對電(dian)(dian)(dian)(dian)路(lu)各個(ge)部(bu)分進行(xing)合理計算設計。本設計使用(yong)賽特公(gong)司生產的(de)12 V, 65 Ah膠(jiao)體密(mi)封鉛(qian)酸蓄電(dian)(dian)(dian)(dian)池(chi)(chi)， 根(gen)(gen)據廠家(jia)提供的(de)蓄電(dian)(dian)(dian)(dian)池(chi)(chi)充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)參(can)數， 浮充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)壓(ya)UF 取13. 8 V,充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)使能電(dian)(dian)(dian)(dian)壓(ya)UT 取10. 8 V; 過(guo)壓(ya)充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)壓(ya)UOC 14. 7V; 涓流(liu)充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)流(liu)I TC 取0. 26 A; 恒流(liu)充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)流(liu)I BU LK 取系(xi)統最大充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)流(liu)6. 5 A; 過(guo)充(chong)(chong)(chong)終止電(dian)(dian)(dian)(dian)流(liu)IOCT 取1 A.

　　根(gen)據以(yi)上(shang)廠家所(suo)提(ti)供的蓄電池參(can)數(shu)， 參(can)照UC3909 芯片資料(liao)及相關參(can)考(kao)文獻，計算U C3909 外(wai)圍(wei)元件參(can)數(shu)， R S1、RS2 、RS3、RS4計算公式如下(xia)：

　　式中， UREF 為UC3909 內部(bu)基準電壓2. 3 V.代入相(xiang)關值計算得（ R S1、RS2、RS3、RS4 分別為245 k Ω 、16 kΩ  、53kΩ 、975 kΩ 。

　　另外， 可以(yi)根據流(liu)(liu)入U C3909 內部電流(liu)(liu)誤差放大器(qi)反(fan)向(xiang)輸出端CA 的固定控制(zhi)電流(liu)(liu)ITRCK 、涓流(liu)(liu)充(chong)電電流(liu)(liu)I T 、恒流(liu)(liu)充(chong)電電流(liu)(liu)IBULK及過充(chong)終止電流(liu)(liu)IOCT 計算(suan)得出RG1、RG2 , R OVC1和ROVC2 , 其(qi)基本計算(suan)公式如下：

　　RSET 取11. 5 k  , 電流采樣電阻RS 取55 m  , 代入式（ 5）、（ 6） 得：

ROVC1和R OVC2滿足以下(xia)關(guan)系(xi)式(shi):

　　最終ROVC1和ROVC2 分別選取為1 k Ω  , 10 kΩ