鑒于市場上鎳鎘電池和鋰電池共存的局面，本文設計的充電器可以對這兩種(zhong)電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)進行充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)，對鎳鎘電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)組采用脈沖充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)方(fang)式，對鋰電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)組采用恒流(liu)充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)方(fang)式，這是依據電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)的(de)不同(tong)機(ji)理而設計的(de)，真(zhen)正做到(dao)了(le)一機(ji)兩用，此為該充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)器(qi)的(de)創(chuang)新(xin)點，也是設計的(de)難(nan)點。充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)器(qi)的(de)寬屏LCD可以同(tong)時顯示4組充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)器(qi)的(de)充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)狀態，也可單獨顯示一組充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)器(qi)上(shang)電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)的(de)各項(xiang)參數，做到(dao)了(le)對電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)過程的(de)實時監測。

　　系統整體設計

　　系(xi)統(tong)設計目標是：

　　1．可(ke)同(tong)時對4組8.4V的鋰離(li)子(zi)電(dian)池(chi)或9.2V的鎳鎘電(dian)池(chi)進行充放(fang)電(dian)。

　　2．可與電(dian)池(chi)組中(zhong)的(de)芯片通信(xin)，判斷電(dian)池(chi)的(de)化學(xue)性質。

　　3．對(dui)于不同化(hua)學性質的(de)電池(chi)，將(jiang)采用相應的(de)充電方式。

　　4．可與電(dian)(dian)池(chi)組中的(de)芯片通信，得到(dao)該(gai)電(dian)(dian)池(chi)組的(de)電(dian)(dian)壓、充電(dian)(dian)電(dian)(dian)流、容(rong)量(liang)等參數(shu)。

　　5．充電器帶有LCD，可顯示電池的各項數(shu)據。

　　該充電器的功能框圖如圖1所示。

　　
       系(xi)統硬件(jian)設計

　　總控單元的設(she)計與實現

　　總控單元是(shi)由(you)微控制器PIC16F873和鍵盤控制芯片ZLG7289A構成的。主要任務是(shi)負責與各(ge)

個(ge)充(chong)(chong)電(dian)(dian)單(dan)(dan)元(yuan)通信(xin)，并(bing)處(chu)理用(yong)戶輸入與(yu)LCD顯(xian)示信(xin)息(xi)。鍵盤控(kong)(kong)制(zhi)芯片在(zai)這里負責6個(ge)按鍵和12個(ge)LED的控(kong)(kong)制(zhi)。ZLG7289A與(yu)微控(kong)(kong)制(zhi)器之(zhi)間通過SPI總線(xian)進行雙向(xiang)通信(xin)。主控(kong)(kong)單(dan)(dan)元(yuan)每秒查詢一次各個(ge)充(chong)(chong)電(dian)(dian)單(dan)(dan)元(yuan)，獲(huo)取(qu)當前充(chong)(chong)電(dian)(dian)單(dan)(dan)元(yuan)的信(xin)息(xi)，如有無電(dian)(dian)池(chi)、電(dian)(dian)池(chi)性質、電(dian)(dian)池(chi)電(dian)(dian)壓等。之(zhi)后(hou)由LCD模塊向(xiang)用(yong)戶顯(xian)示。

　　充(chong)電單元(yuan)的設計與實(shi)現

　　LTC4002鋰離子電(dian)池充電(dian)控制芯片

　　LTC4002是(shi)一款高(gao)(gao)效(xiao)獨立開關模(mo)式鋰離子(zi)電(dian)(dian)(dian)池充(chong)(chong)電(dian)(dian)(dian)控(kong)(kong)制器。該控(kong)(kong)制器有(you)4.2V和(he)8.4V兩個版本。LTC4002-8.4具有(you)500kHz開關頻率，是(shi)高(gao)(gao)效(xiao)電(dian)(dian)(dian)流模(mo)式的PWM控(kong)(kong)制器。通過驅動(dong)一個外部(bu)P溝道MOSFET，它(ta)可(ke)以提供4A的充(chong)(chong)電(dian)(dian)(dian)電(dian)(dian)(dian)流，而效(xiao)率可(ke)高(gao)(gao)達90％。輸出電(dian)(dian)(dian)壓(ya)設(she)置為(wei)8.4V，最終浮動(dong)電(dian)(dian)(dian)壓(ya)并具1％的精度，而充(chong)(chong)電(dian)(dian)(dian)準確(que)度為(wei)5％。此(ci)外，該器件可(ke)在9V～22V范(fan)圍(wei)內的多種墻上(shang)適配器上(shang)運行。與遲滯拓(tuo)撲結構充(chong)(chong)電(dian)(dian)(dian)器相比，LTC4002-8.4的快(kuai)速運行頻率與電(dian)(dian)(dian)流模(mo)式架構使之能夠使用小型電(dian)(dian)(dian)感(gan)器和(he)電(dian)(dian)(dian)容器。

　　鋰離子／鎳鎘(ge)電(dian)池兩用充(chong)電(dian)單元的(de)總體設(she)計

　　從前面對(dui)LTC4002的(de)分(fen)析可知(zhi)，該芯片是針(zhen)對(dui)鋰(li)離(li)(li)子(zi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)的(de)充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)控制器，要實現(xian)對(dui)鎳(nie)(nie)鎘(ge)(ge)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)需要解決以(yi)下問題：首先，LTC4002對(dui)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓進(jin)行(xing)監測，保證(zheng)(zheng)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓不超(chao)過8.4V。但對(dui)于鎳(nie)(nie)鎘(ge)(ge)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)組，充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)截止電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓可以(yi)達到9.2V。其(qi)次，鎳(nie)(nie)鎘(ge)(ge)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)即將結束時，需要對(dui)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)進(jin)行(xing)以(yi)正常電(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)30％和10％的(de)涓流(liu)充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)。所以(yi)，第二(er)個(ge)(ge)需要解決的(de)問題是如何(he)控制恒(heng)流(liu)充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)的(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)大(da)小。此外，對(dui)鎳(nie)(nie)鎘(ge)(ge)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)應使用脈沖充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)方式(shi)。即以(yi)1s為(wei)周(zhou)期，95％的(de)時間(jian)用來(lai)充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)，1％的(de)時間(jian)用來(lai)放電(dian)(dian)(dian)(dian)(dian)(dian)(dian)，其(qi)余時間(jian)不充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)也不放電(dian)(dian)(dian)(dian)(dian)(dian)(dian)。最(zui)后，如何(he)判(pan)斷(duan)某一個(ge)(ge)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)是鋰(li)離(li)(li)子(zi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)還(huan)是鎳(nie)(nie)鎘(ge)(ge)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)，因(yin)為(wei)若把鋰(li)離(li)(li)子(zi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)誤(wu)判(pan)為(wei)鎳(nie)(nie)鎘(ge)(ge)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)，會使充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓高于8.4V，這對(dui)鋰(li)離(li)(li)子(zi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)是十分(fen)危(wei)險的(de)，而將鎳(nie)(nie)鎘(ge)(ge)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)誤(wu)判(pan)為(wei)鋰(li)離(li)(li)子(zi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)，則可能造成電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)(chi)充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)不足。因(yin)此，必須保證(zheng)(zheng)極低(di)的(de)誤(wu)判(pan)率(lv)。

　　本部分根據LTC4002的工作原理，設計(ji)了既(ji)可以(yi)對鋰(li)離子電(dian)(dian)(dian)(dian)(dian)(dian)池進行恒流(liu)-恒壓(ya)充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)，又可以(yi)對鎳鎘電(dian)(dian)(dian)(dian)(dian)(dian)池進行脈沖式充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)的電(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)。充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)單元的總體(ti)功能框圖如圖2所示。其(qi)中(zhong)，信號調(diao)理電(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)使充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)器既(ji)可以(yi)對8.4V的鋰(li)電(dian)(dian)(dian)(dian)(dian)(dian)池充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)，又可以(yi)對9.2V的鎳鎘電(dian)(dian)(dian)(dian)(dian)(dian)池充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)，同時也(ye)起到(dao)控制充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)流(liu)大小的作用(yong)。

　　利用(yong)微控(kong)制(zhi)器(qi)控(kong)制(zhi)LTC4002的(de)工(gong)作狀(zhuang)態，配合(he)放電(dian)(dian)電(dian)(dian)路使充電(dian)(dian)器(qi)可(ke)以對鎳鎘電(dian)(dian)池進行脈(mo)沖(chong)方式充電(dian)(dian)。

　　微(wei)控制器通(tong)過一(yi)定的通(tong)信(xin)協議(yi)(HDQ16)與智(zhi)能電池通(tong)信(xin)，確(que)定其容量、化學性質(zhi)等(deng)關鍵參數。

　　信號調理(li)電路(lu)的(de)設(she)計

　　為了使LTC4002可對(dui)高于8.4V的(de)電(dian)(dian)(dian)(dian)(dian)池(chi)進行恒流(liu)充電(dian)(dian)(dian)(dian)(dian)，并可調(diao)節充電(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)流(liu)，在LTC4002的(de)BAT和SENSE端(duan)與采樣電(dian)(dian)(dian)(dian)(dian)阻之間加入一級信(xin)號(hao)調(diao)理電(dian)(dian)(dian)(dian)(dian)路。該(gai)(gai)電(dian)(dian)(dian)(dian)(dian)路的(de)主(zhu)要功能是對(dui)采樣電(dian)(dian)(dian)(dian)(dian)阻兩(liang)端(duan)的(de)信(xin)號(hao)進行運算，針對(dui)不同化學(xue)性質的(de)電(dian)(dian)(dian)(dian)(dian)池(chi)，將相應的(de)信(xin)號(hao)送給LTC4002。該(gai)(gai)信(xin)號(hao)調(diao)理電(dian)(dian)(dian)(dian)(dian)路如圖3所示(shi)。

這(zhe)(zhe)里定義采樣電(dian)(dian)(dian)(dian)阻(zu)(zu)兩端的(de)(de)電(dian)(dian)(dian)(dian)壓(ya)值是VBAT和(he)(he)Vsense，那么充電(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)流在采樣電(dian)(dian)(dian)(dian)阻(zu)(zu)上的(de)(de)壓(ya)降VRS為(wei)(wei)(wei)(wei)：VRS=Vsense-VBAT，該信號為(wei)(wei)(wei)(wei)減(jian)法(fa)(fa)器(qi)的(de)(de)輸(shu)出。設乘(cheng)法(fa)(fa)器(qi)的(de)(de)乘(cheng)系數(shu)為(wei)(wei)(wei)(wei)K，那么乘(cheng)法(fa)(fa)器(qi)的(de)(de)輸(shu)出為(wei)(wei)(wei)(wei)KVRS。對于鋰子電(dian)(dian)(dian)(dian)池，二(er)(er)選(xuan)一(yi)開關將選(xuan)通電(dian)(dian)(dian)(dian)池電(dian)(dian)(dian)(dian)壓(ya)VBAT；對于鎳鎘(ge)電(dian)(dian)(dian)(dian)池，二(er)(er)選(xuan)一(yi)開關將選(xuan)通7V恒(heng)定電(dian)(dian)(dian)(dian)壓(ya)。這(zhe)(zhe)里設二(er)(er)選(xuan)一(yi)模擬開關的(de)(de)輸(shu)出為(wei)(wei)(wei)(wei)V1，那么加法(fa)(fa)器(qi)的(de)(de)輸(shu)出Vs應為(wei)(wei)(wei)(wei)：Vs=KVRS+V1，這(zhe)(zhe)樣一(yi)來，送到LTC4002的(de)(de)BAT和(he)(he)SENSE兩端的(de)(de)電(dian)(dian)(dian)(dian)壓(ya)之(zhi)差應為(wei)(wei)(wei)(wei)KVRS。只要正確控制K值，就可(ke)以(yi)使充電(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)流為(wei)(wei)(wei)(wei)正常充電(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)流的(de)(de)1／K。因(yin)此，可(ke)以(yi)通過二(er)(er)選(xuan)一(yi)開關控制電(dian)(dian)(dian)(dian)流為(wei)(wei)(wei)(wei)恒(heng)流充電(dian)(dian)(dian)(dian)時的(de)(de)10％或30％。

　　對于LTC4002的(de)BAT端輸入(ru)值(zhi)，當開(kai)關選通鋰(li)離子電池(chi)時，BAT的(de)輸入(ru)即(ji)是電池(chi)電壓。此時，LTC4002可以控制整(zheng)個鋰(li)離子的(de)充電過程(cheng)。不需任何外界的(de)干預。

　　當開關選通了7V恒定(ding)電(dian)(dian)(dian)(dian)壓(ya)后，BAT端的輸(shu)入恒定(ding)為7V，此時(shi)，LTC4002無法知道電(dian)(dian)(dian)(dian)池的真實電(dian)(dian)(dian)(dian)壓(ya)，只認為電(dian)(dian)(dian)(dian)池電(dian)(dian)(dian)(dian)壓(ya)為7V。所以(yi)，盡管(guan)電(dian)(dian)(dian)(dian)池電(dian)(dian)(dian)(dian)壓(ya)高于8.4V，仍會以(yi)恒定(ding)電(dian)(dian)(dian)(dian)流對(dui)電(dian)(dian)(dian)(dian)池進行(xing)充(chong)(chong)電(dian)(dian)(dian)(dian)。在這(zhe)種情況(kuang)下(xia)，需要微(wei)控制器(qi)的干預，否(fou)則，會造成電(dian)(dian)(dian)(dian)池的過(guo)充(chong)(chong)。由于微(wei)控制器(qi)內部(bu)帶有ADC，可(ke)以(yi)監測電(dian)(dian)(dian)(dian)池電(dian)(dian)(dian)(dian)壓(ya)的變(bian)化。當電(dian)(dian)(dian)(dian)池電(dian)(dian)(dian)(dian)壓(ya)達(da)到指定(ding)值(zhi)時(shi)，減小充(chong)(chong)電(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)流，直至電(dian)(dian)(dian)(dian)池充(chong)(chong)滿(man)。這(zhe)樣就(jiu)可(ke)以(yi)對(dui)9.2V的鎳鎘電(dian)(dian)(dian)(dian)池進行(xing)充(chong)(chong)電(dian)(dian)(dian)(dian)了。

　　脈沖充(chong)放電(dian)電(dian)路(lu)的設(she)計(ji)

　　由于LTC4002是(shi)恒(heng)流充(chong)(chong)(chong)電(dian)(dian)(dian)控(kong)制(zhi)(zhi)(zhi)芯片，因(yin)此，必須使(shi)用微控(kong)制(zhi)(zhi)(zhi)器控(kong)制(zhi)(zhi)(zhi)其充(chong)(chong)(chong)電(dian)(dian)(dian)使(shi)能(neng)引腳(jiao)COMP。當需要LTC4002輸(shu)出充(chong)(chong)(chong)電(dian)(dian)(dian)脈沖時(shi)，使(shi)控(kong)制(zhi)(zhi)(zhi)COMP引腳(jiao)的端口變為高阻態，使(shi)COMP引腳(jiao)自行升至360mV以上時(shi)，便有充(chong)(chong)(chong)電(dian)(dian)(dian)電(dian)(dian)(dian)流輸(shu)出。放(fang)電(dian)(dian)(dian)時(shi)，必須將COMP引腳(jiao)拉低，使(shi)LTC4002關(guan)斷(duan)充(chong)(chong)(chong)電(dian)(dian)(dian)電(dian)(dian)(dian)流。之(zhi)后，再打開放(fang)電(dian)(dian)(dian)電(dian)(dian)(dian)路。微控(kong)制(zhi)(zhi)(zhi)器選用PIC16F873，它是(shi)一款基(ji)于Fla

sh的(de)8位微控制器(qi)。內(nei)部(bu)有定時器(qi)、看門(men)狗電(dian)路(lu)、10位ADC等模塊(kuai)。

　　微控制(zhi)器以(yi)1s為周(zhou)期(qi)對鎳鎘(ge)電池(chi)進(jin)行脈沖充(chong)放電。

　　系統軟件設計

　　系統軟件總體設(she)計

　　充電(dian)(dian)(dian)(dian)(dian)單元中的(de)(de)微控(kong)(kong)制(zhi)器主要負責(ze)充電(dian)(dian)(dian)(dian)(dian)過程(cheng)的(de)(de)控(kong)(kong)制(zhi)和與總(zong)控(kong)(kong)板的(de)(de)通信(xin)，程(cheng)序(xu)流(liu)程(cheng)如圖4所示(shi)。充電(dian)(dian)(dian)(dian)(dian)單元首先判(pan)(pan)斷是(shi)否有電(dian)(dian)(dian)(dian)(dian)池(chi)(chi)，如果有電(dian)(dian)(dian)(dian)(dian)池(chi)(chi)放(fang)入，則判(pan)(pan)斷充放(fang)電(dian)(dian)(dian)(dian)(dian)狀態(tai)，默認是(shi)充電(dian)(dian)(dian)(dian)(dian)狀態(tai)，該狀態(tai)可(ke)由總(zong)控(kong)(kong)單元改變。若充電(dian)(dian)(dian)(dian)(dian)單元處于充電(dian)(dian)(dian)(dian)(dian)狀態(tai)，則繼(ji)續判(pan)(pan)斷電(dian)(dian)(dian)(dian)(dian)池(chi)(chi)的(de)(de)化(hua)學性質，針對不(bu)同的(de)(de)電(dian)(dian)(dian)(dian)(dian)池(chi)(chi)采用不(bu)同的(de)(de)充電(dian)(dian)(dian)(dian)(dian)方式。若處于放(fang)電(dian)(dian)(dian)(dian)(dian)狀態(tai)，則對電(dian)(dian)(dian)(dian)(dian)池(chi)(chi)組進行放(fang)電(dian)(dian)(dian)(dian)(dian)，直到電(dian)(dian)(dian)(dian)(dian)池(chi)(chi)電(dian)(dian)(dian)(dian)(dian)壓(ya)低于閾(yu)值電(dian)(dian)(dian)(dian)(dian)壓(ya)后，轉為充電(dian)(dian)(dian)(dian)(dian)狀態(tai)。

　　除主(zhu)程序(xu)(xu)外，總(zong)控單元(yuan)(yuan)與充(chong)電(dian)單元(yuan)(yuan)的(de)(de)通信(xin)是在中(zhong)(zhong)斷服務(wu)程序(xu)(xu)中(zhong)(zhong)實現的(de)(de)。當充(chong)電(dian)單元(yuan)(yuan)收到總(zong)控單元(yuan)(yuan)的(de)(de)指(zhi)(zhi)(zhi)令(ling)后，進入中(zhong)(zhong)斷。若指(zhi)(zhi)(zhi)令(ling)是查詢數(shu)據(ju)(ju)指(zhi)(zhi)(zhi)令(ling)，則向總(zong)控單元(yuan)(yuan)發(fa)送需(xu)要的(de)(de)數(shu)據(ju)(ju)。若是充(chong)電(dian)狀(zhuang)態(tai)設置(zhi)指(zhi)(zhi)(zhi)令(ling)，則依(yi)據(ju)(ju)指(zhi)(zhi)(zhi)令(ling)設置(zhi)充(chong)電(dian)單元(yuan)(yuan)的(de)(de)充(chong)電(dian)狀(zhuang)態(tai)。

　　通信協議的實現

　　通過與電池組中電能計量芯片通信的方法來判斷電池的性質。本系統可以與遵循HDQ16接口協議的智能電池組進行通信，除了電池組的化學性質外，還可以將電池組的容量、電壓、充電電流、編號等數據一并讀取，供充電器顯示之用。

　　充電(dian)單元可以通過(guo)HDQ總線對(dui)智能(neng)電(dian)池(chi)進行讀操(cao)作。HDQ16接(jie)口(kou)協議是(shi)基于指(zhi)(zhi)令(ling)的(de)(de)協議。一個處理器發送(song)8位(wei)(wei)(wei)指(zhi)(zhi)令(ling)碼(ma)給智能(neng)電(dian)池(chi)，這個8位(wei)(wei)(wei)的(de)(de)指(zhi)(zhi)令(ling)碼(ma)由兩部分組成，7位(wei)(wei)(wei)HDQ16指(zhi)(zhi)令(ling)碼(ma)(位(wei)(wei)(wei)0～6)和(he)1位(wei)(wei)(wei)讀／寫(xie)指(zhi)(zhi)令(ling)。讀／寫(xie)指(zhi)(zhi)令(ling)指(zhi)(zhi)示(shi)智能(neng) 電(dian)池(chi)存儲接(jie)下(xia)來的(de)(de)16位(wei)(wei)(wei)數(shu)(shu)據到(dao)一個指(zhi)(zhi)定的(de)(de)寄(ji)存器，或者從指(zhi)(zhi)定的(de)(de)寄(ji)存器輸出16位(wei)(wei)(wei)數(shu)(shu)據。在(zai)HDQ16里，數(shu)(shu)據字節(指(zhi)(zhi)令(ling))或者字(數(shu)(shu)據)的(de)(de)最不重(zhong)要的(de)(de)位(wei)(wei)(wei)會優(you)先(xian)傳輸。

　　一個塊的(de)傳(chuan)輸(shu)包括三個不同的(de)部(bu)分(fen)(fen)(fen)。第一部(bu)分(fen)(fen)(fen)經由主機或者(zhe)智能電(dian)池(chi)把HDQ16引(yin)腳置邏輯(ji)低(di)狀態一個tSTRH：B時(shi)(shi)(shi)間(jian)后(hou)開始(shi)發送。接下(xia)來的(de)部(bu)分(fen)(fen)(fen)是真正的(de)數據傳(chuan)輸(shu)，數據位在tDSU:B時(shi)(shi)(shi)間(jian)間(jian)隔里是有效的(de)，負邊界用(yong)來開始(shi)通(tong)信(xin)。數據位被保持一個tDH:DV時(shi)(shi)(shi)間(jian)間(jian)隔，以便允許(xu)主機或智能電(dian)池(chi)采樣數據位。

　　在負(fu)邊界(jie)開始(shi)通信后，最后一(yi)部分通過(guo)返回給HDQ16引腳一(yi)個(ge)邏(luo)輯高狀態(tai)，至少保持(chi)tSSU:B時間間隔來(lai)停(ting)止(zhi)傳輸。最后一(yi)個(ge)邏(luo)輯高狀態(tai)必須保持(chi)一(yi)個(ge)tCYCH:B時間間隔，以(yi)便(bian)有時間讓塊傳輸完全(quan)停(ting)止(zhi)。

　　如果(guo)發生通信錯誤(e.g.，tCYCB>250μs)，主機(ji)就(jiu)發送給智(zhi)能電池一個(ge)(ge)BREAK信號，讓其控制串行接(jie)口。當HDQ16引(yin)腳(jiao)在(zai)一個(ge)(ge)時(shi)(shi)間間隔，或(huo)者(zhe)更長時(shi)(shi)間里(li)為邏輯低狀態(tai)時(shi)(shi)，智(zhi)能電池就(jiu)會偵測(ce)BREAK。然后(hou)，HDQ16引(yin)腳(jiao)回到其正常預設(she)高(gao)邏輯狀態(tai)一個(ge)(ge)tBR時(shi)(shi)間間隔。然后(hou)，智(zhi)能電池就(jiu)準備從主機(ji)那里(li)接(jie)收指令。

　　HDQ16引腳(jiao)是(shi)開(kai)漏(lou)的(de)，需要一(yi)個(ge)外部(bu)的(de)上拉電阻。

　　圖5是用邏輯分(fen)析儀顯示(shi)的一次HDQ總線上(shang)的通信波形。

　　本文提(ti)出的(de)充電(dian)(dian)(dian)(dian)系統從技(ji)術(shu)(shu)上很好地解決了上述問題(ti)，通過(guo)LCD顯示屏可以(yi)清(qing)晰便捷地讀出電(dian)(dian)(dian)(dian)源的(de)剩余(yu)容量(liang)、已有充放(fang)電(dian)(dian)(dian)(dian)次數、充電(dian)(dian)(dian)(dian)及(ji)放(fang)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)、容量(liang)統計(ji)和電(dian)(dian)(dian)(dian)池特性(xing)等重要內容，并且通過(guo)設定，可以(yi)判斷電(dian)(dian)(dian)(dian)源是(shi)否達到(dao)報(bao)廢標準，及(ji)時提(ti)醒操作(zuo)(zuo)(zuo)者更新電(dian)(dian)(dian)(dian)源。為電(dian)(dian)(dian)(dian)源維護(hu)保養工(gong)作(zuo)(zuo)(zuo)提(ti)供明確(que)的(de)參(can)考數據，降低了對(dui)操作(zuo)(zuo)(zuo)人員專業技(ji)術(shu)(shu)水平的(de)要求，保證了列車尾部電(dian)(dian)(dian)(dian)源的(de)安全使用。