電動車36V鋰電池組保護電路設計方案
隨著電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)動(dong)自(zi)行(xing)車的(de)(de)(de)逐漸普及，電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)動(dong)自(zi)行(xing)車的(de)(de)(de)主要能(neng)源(yuan)---鋰(li)(li)(li)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)也成(cheng)(cheng)為(wei)眾人關心的(de)(de)(de)焦點。 鋰(li)(li)(li)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)與鎳(nie)鎘、鎳(nie)氫電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)不(bu)太一樣，因其能(neng)量密度高(gao)(gao)，對充放(fang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)要求很高(gao)(gao)。 當過(guo)(guo)充、過(guo)(guo)放(fang)、過(guo)(guo)流及短路(lu)(lu)保(bao)護等情(qing)況發生(sheng)時，鋰(li)(li)(li)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)內的(de)(de)(de)壓力與熱量大量增加，容易產生(sheng)爆炸，因此通常(chang)都(dou)會(hui)在(zai)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)包內加保(bao)護電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)，用(yong)以提高(gao)(gao)鋰(li)(li)(li)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)的(de)(de)(de)使用(yong)壽命。 針(zhen)對目前電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)動(dong)車鋰(li)(li)(li)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)組(zu)所(suo)用(yong)的(de)(de)(de)保(bao)護電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)大多都(dou)由分立原件構成(cheng)(cheng)，存在(zai)控(kong)制(zhi)精度不(bu)夠高(gao)(gao)、技術指標(biao)低、不(bu)能(neng)有效保(bao)護鋰(li)(li)(li)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)組(zu)等特點，本文中提出一種基于單片機(ji)的(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)動(dong)車36 V鋰(li)(li)(li)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)組(zu)（由10節(jie)3. 6 V鋰(li)(li)(li)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)串聯而成(cheng)(cheng)）保(bao)護電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)設計方案(an)，利用(yong)高(gao)(gao)性能(neng)、低功(gong)耗的(de)(de)(de)ATmega16L 單片機(ji)作為(wei)檢測和(he)控(kong)制(zhi)核心，用(yong)由MC34063構成(cheng)(cheng)的(de)(de)(de)DC /DC變(bian)換(huan)控(kong)制(zhi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)為(wei)整個保(bao)護電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)提供穩壓電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)，輔(fu)以LM60 測溫、MOS管IRF530N作充放(fang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)控(kong)制(zhi)開關，實現對整個電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)組(zu)和(he)單個電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)的(de)(de)(de)狀態監(jian)控(kong)和(he)保(bao)護功(gong)能(neng)，達(da)到延長電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)使用(yong)壽命的(de)(de)(de)目的(de)(de)(de)。
1 保護電路硬件設計
本系(xi)統以單片機為數據處理(li)和控(kong)制的核心，將(jiang)任務(wu)設計分(fen)解為電壓測量、電流測量、溫(wen)度測量、開關(guan)控(kong)制、電源、均衡充電等(deng)功能模塊。 系(xi)統的總體框圖如圖1所示(shi)。
圖(tu)1 系統的總體框圖(tu)
電(dian)(dian)池(chi)組(zu)電(dian)(dian)壓、電(dian)(dian)流、溫度等(deng)信息通過電(dian)(dian)壓采樣(yang)、電(dian)(dian)流采樣(yang)和(he)溫度測量電(dian)(dian)路，加到信號采集部分的(de)A /D輸(shu)入端(duan)。 A /D模(mo)塊將輸(shu)入的(de)模(mo)擬(ni)信號轉換為數字信號，并傳(chuan)輸(shu)給(gei)單(dan)(dan)片機。 單(dan)(dan)片機作為數據處(chu)理和(he)控制(zhi)(zhi)的(de)核心，一方(fang)面(mian)實時監(jian)控電(dian)(dian)池(chi)組(zu)的(de)各(ge)項性能(neng)指(zhi)標和(he)狀態，一方(fang)面(mian)根(gen)據這些狀態參(can)數控制(zhi)(zhi)驅動大功(gong)率開關。 由于使用了(le)單(dan)(dan)片機，使系(xi)統具(ju)有很(hen)大的(de)靈活性，便于實現各(ge)種復雜控制(zhi)(zhi)，從而能(neng)方(fang)便地對系(xi)統進行功(gong)能(neng)擴展和(he)性能(neng)改(gai)進。
1. 1 ATmega16 L單片機模塊
從低功耗、低成本設計角度出發，單片機模塊采用高性能、低功耗的ATmega16 L單片機作為檢測與控制核心。 ATmega16 L 是基于增強的AVRR ISC結構的低功耗8位CMOS微控制器，內部帶有16 k 字節的系統內可編程Flash, 512 字節EEPROM, 1 k字節SRAM, 32個通用I/O口線， 32個通用工作寄存器（用于邊界掃描的JTAG接口，支持片內調試與編程） , 3個具有比較模式的靈活定時器/計數器（ T/C） （片內/外中斷） ,可編程串行USART,有起始條件檢測器的通用串行接口， 8路10位具有可選差分輸入級可編程增益（ TQFP封裝）的ADC,具有片內振蕩器的可編程看門狗定時器，一個SP I串行端口，以及6個可以通過軟件進行選擇的省電模式。 由于其先進的指令集以及單時鐘周期指令執行時間，ATmega16 L的數據吞吐率高達1M IPS/MHz,從而可以緩減系統功耗和處理速度之間的矛盾。
單片機的輸入輸出設計如圖2所示。 由電源部分降壓、穩壓得到的3. 3 V電壓通過端口10為單片機提供工作電壓；端口12和13為反向振蕩放大器與片內時鐘操作電路的輸入端和反向振蕩放大器的輸出端，為單片機提供工作晶振；端口30是端口A與A /D轉換器的電源，使用ADC時通過一個低通濾波器與端口10的VCC連接；端口37,38的ADC3, ADC2是經過轉換后待檢測的電壓、電流值；端口39, 40的ADC1,ADC0是經過溫度傳感器轉換后的溫控電壓值。
圖2 單(dan)片(pian)機的外圍電路設計
1. 2 穩壓電源模塊
穩壓電源是單片機系統的重要組成部分，它不僅為系統提供多路電源電壓，還直接影響到系統的技術指標和抗干擾性能。 ATmega16 L單片機的工作電壓為2. 7~5. 5 V,為保證單片機穩定的工作電壓為3. 3 V. 穩壓部分是由MC34063構成的DC /DC變換控制電路，從電池組分出的25 V電壓經過電路降壓、穩壓，輸出3. 3 V,供保護電路工作，其電路如圖3所示。
圖3 穩壓電源(yuan)模塊電路
1. 3 充電均衡模塊
采用模擬電路方案。 即在每節電池的外部搭建過壓保護電路，充電過程中當電壓超過預定值時，保護電路自動閉合，使電池通過電阻回路放電，以保護電池不會過度充電。 當電池電壓減小到均衡充電動作電壓4. 18 V時，保護電路自動斷開。
1. 4 電壓電流測量模塊
待測的電壓通過集成運算放大器LM358,將輸出送至單片機進行檢測。 LM358內部包括2個獨立、高增益、內部頻率補償的雙運算放大器，適合于電源電壓范圍很寬的單電源使用和雙電源工作模式，由于其低功耗電流，也適合于電池。 用霍爾傳感器UGN - 3501 M 檢測直流電流。 UGN -3501M是集成型霍爾傳感器，采用差動霍爾電壓輸出，檢測靈敏度為1. 4 V /0. 1T.
電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)電(dian)(dian)(dian)(dian)(dian)(dian)流檢測(ce)(ce)電(dian)(dian)(dian)(dian)(dian)(dian)路的設計如圖(tu)4 所(suo)示(shi)。 運算放(fang)大(da)器LM358的5, 6引(yin)腳(jiao)所(suo)接(jie)的BB,AA為待測(ce)(ce)的充(chong)電(dian)(dian)(dian)(dian)(dian)(dian)、放(fang)電(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)，經過(guo)(guo)放(fang)大(da)后由7腳(jiao)輸(shu)出(chu)至(zhi)單片(pian)(pian)機進行(xing)檢測(ce)(ce)，當檢測(ce)(ce)到(dao)待測(ce)(ce)電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)達(da)到(dao)過(guo)(guo)充(chong)、過(guo)(guo)放(fang)保護(hu)(hu)電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)時，由單片(pian)(pian)機控(kong)制(zhi)斷開充(chong)放(fang)電(dian)(dian)(dian)(dian)(dian)(dian)回路。 電(dian)(dian)(dian)(dian)(dian)(dian)流檢測(ce)(ce)通過(guo)(guo)霍(huo)爾(er)傳感器完成，如圖(tu)4所(suo)示(shi)，將從UGN -3501M1, 8引(yin)腳(jiao)輸(shu)出(chu)的霍(huo)爾(er)電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)uH 接(jie)至(zhi)LM358的3, 4引(yin)腳(jiao)，經過(guo)(guo)放(fang)大(da)后從1 腳(jiao)輸(shu)出(chu)ADC3 至(zhi)單片(pian)(pian)機，進行(xing)過(guo)(guo)電(dian)(dian)(dian)(dian)(dian)(dian)流保護(hu)(hu)。 UGN - 3501M 的5, 6, 7引(yin)腳(jiao)連(lian)接(jie)調整(zheng)電(dian)(dian)(dian)(dian)(dian)(dian)位(wei)器，用以(yi)補(bu)償不等(deng)位(wei)電(dian)(dian)(dian)(dian)(dian)(dian)勢(shi)，同時改善線性。 調整(zheng)5, 6引(yin)腳(jiao)外接(jie)電(dian)(dian)(dian)(dian)(dian)(dian)阻R16,可(ke)使(shi)輸(shu)出(chu)霍(huo)爾(er)電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)uH 與(yu)磁場強度有較好的線性關系。
圖4 電壓電流(liu)檢測電路(lu)
1. 5 溫度檢測模塊
溫度檢測和控制模塊選用電壓輸出型的半導體溫度傳感器LM60. 該傳感器是一種已校正的集成化溫度傳感器，它的工作溫度范圍是- 40 ℃至125 ℃，工作電壓范圍是2. 7 V至10 V. 信號輸出與溫度成正比，信號大小可達+ 6. 25 mV /℃。
基于LM60的(de)溫(wen)度(du)檢測電(dian)路如圖5所示。 由穩壓部分輸出的(de)3. 3 V 電(dian)源(yuan)為此電(dian)路供(gong)電(dian)，經(jing)過溫(wen)度(du)傳(chuan)感器將探(tan)測點的(de)溫(wen)度(du)轉(zhuan)化為電(dian)壓值通過ADC0,ADC1輸出，再將ADC0, ADC1送(song)入單片(pian)機(ji)進行(xing)檢測，當電(dian)壓值達到溫(wen)控(kong)要求時(shi)，單片(pian)機(ji)控(kong)制開(kai)關通斷。
圖5 溫(wen)度檢測電(dian)路
1. 6 開關模塊
開關采用MOSFET,型號選用P溝道的MOS管的IR530N. 工作原理：單片機控制端口輸出高電平，功率三極管導通，功率場效應管的柵極和漏極之間產生壓降，功率場效應管導通。
2 軟件設計
本系(xi)統(tong)軟(ruan)件(jian)采用(yong)C語言編(bian)寫，處理程(cheng)序(xu)采用(yong)模塊化編(bian)程(cheng)， 程(cheng)序(xu)運行的(de)環境是ICCAVR 開發系(xi)統(tong)。
在電(dian)(dian)池(chi)組空(kong)載(zai)的(de)時候，系統進入掉電(dian)(dian)模式(shi)(shi)，以(yi)使功(gong)耗(hao)(hao)降(jiang)至(zhi)最低；當電(dian)(dian)池(chi)組接入負載(zai)或對(dui)電(dian)(dian)池(chi)組充電(dian)(dian)時，單片機被激活，由(you)低功(gong)耗(hao)(hao)掉電(dian)(dian)模式(shi)(shi)轉入正常工作(zuo)模式(shi)(shi)，并持續運作(zuo)。 整個程序的(de)流程如圖6所示(shi)。
圖6 程序流程
根(gen)據(ju)本系統的(de)模(mo)塊(kuai)分(fen)布，單片機程(cheng)序分(fen)為電(dian)壓(ya)測量(liang)模(mo)塊(kuai)、電(dian)流測量(liang)模(mo)塊(kuai)和溫(wen)度測量(liang)模(mo)塊(kuai)，每一(yi)模(mo)塊(kuai)調用共同(tong)A /D轉換函數(shu)和延時判斷函數(shu)等，以縮(suo)短代碼長(chang)度和增強程(cheng)序代碼的(de)可讀性。 下面給出程(cheng)序主(zhu)函數(shu)的(de)代碼：
void main （void）
{
int （ ） ; / /單片機初始化，打開所有開關；
sleep （ ） ; / /單片機進入休眠模式；
int sign |= 1;
while （ sign = = 1 ） / /判斷系統是否運行正常；
{ int（ ） ;
dianya （ ） ; / /調用測壓模塊；
delay（30000） ;
delay（30000） ;
dianliu （ ） ; / /調用測流模塊；
delay（30000） ;
delay（30000） ;
wendu （ ） ; / /調用溫度模塊；
delay（30000） ;
delay（30000） ;
}
int （ ） ;
sign |= 1;
main （ ） ;
}
3 結束語
通過(guo)實驗，本(ben)(ben)保護(hu)電路系統(tong)(tong)實現了全部基本(ben)(ben)功能(neng)(neng)。 與傳統(tong)(tong)采用(yong)分(fen)離元件的電池(chi)保護(hu)系統(tong)(tong)相比，本(ben)(ben)文中提出基于(yu)單片(pian)機的電池(chi)保護(hu)電路系統(tong)(tong)具(ju)有系統(tong)(tong)體積小、功能(neng)(neng)多、功耗(hao)低(di)、成本(ben)(ben)低(di)等特點(dian)，可(ke)用(yong)于(yu)工業(ye)生產。