1 引言

　　該航空蓄電池充電器為(wei)飛(fei)機某型號蓄(xu)電(dian)(dian)(dian)池(chi)專門設(she)計，主要實現兩(liang)階段充(chong)電(dian)(dian)(dian)功能(neng)，即恒流(liu)(liu)充(chong)電(dian)(dian)(dian)狀(zhuang)(zhuang)態（以20A的大電(dian)(dian)(dian)流(liu)(liu)充(chong)電(dian)(dian)(dian)）和(he)涓流(liu)(liu)充(chong)電(dian)(dian)(dian)狀(zhuang)(zhuang)態（以3A的小(xiao)電(dian)(dian)(dian)流(liu)(liu)充(chong)電(dian)(dian)(dian)）。蓄(xu)電(dian)(dian)(dian)池(chi)充(chong)電(dian)(dian)(dian)器(qi)使用的工作電(dian)(dian)(dian)源(yuan)為(wei)115V/400Hz的航空電(dian)(dian)(dian)源(yuan)，充(chong)電(dian)(dian)(dian)器(qi)能(neng)在1小(xiao)時(shi)內完(wan)成恒流(liu)(liu)充(chong)電(dian)(dian)(dian)，隨后以涓流(liu)(liu)狀(zhuang)(zhuang)態對蓄(xu)電(dian)(dian)(dian)池(chi)組進行(xing)充(chong)電(dian)(dian)(dian)直至(zhi)充(chong)電(dian)(dian)(dian)結束，每個充(chong)電(dian)(dian)(dian)過程在2個小(xiao)時(shi)內完(wan)成。

　　2　充電器總體設計方案
 

圖(tu)1 充電器主(zhu)電路結構框圖(tu)

 　　航空蓄電池充電器的主電路如圖1所示，電源變換器采用了由半橋變換器、高頻變壓器和輸出整流濾波電路組成的半橋變換器[1]，該電路結構簡單，工作可靠，功率管為場效應管，而且開關管承受的電壓為電源電壓，故可在電源電壓較高的場合應用。通常高頻大功率變換器開關頻率一般都大于15kHz，為了使功率電路小型化、減小失真并保持高的變換效率，該充電器采(cai)用了(le)20kHz的開關頻(pin)率。

　　3 SG3525芯片介紹
 

圖(tu)2　SG3525芯片的結構圖(tu)

　　SG3525是美國通用公司的產品，如圖2所示，內部電路主要由基準電源、振蕩器、誤差放大器、PWM比較器與鎖存器、分相器、欠電壓鎖定、輸出級、軟啟動以及關斷電路等組成。基準電源是一個典型的三端穩壓器，精度可達，采用了溫度補償。作為內部電路的供電電源，并可向外輸出40mA電流。振蕩器由一個雙門限比較器，一個恒流源及電容充放電電路組成，在芯片外部由5腳對地接一電容器，6腳對地接一電阻，5腳和7腳之間外接電阻即可構成該振蕩器。
 

圖3 SG3525芯片各(ge)點的(de)工(gong)作波形

 　　SG3525芯片各點的(de)(de)(de)工作波形如圖(tu)3所示，由誤差放大(da)(da)器輸出的(de)(de)(de)電(dian)(dian)壓Ve與鋸(ju)齒波的(de)(de)(de)交(jiao)點可(ke)得(de)一負的(de)(de)(de)PWM信號(hao)(hao)。由PWM信號(hao)(hao)、時鐘(zhong)信號(hao)(hao)及(ji)分相(xiang)器輸出的(de)(de)(de)Q (或 )信號(hao)(hao)，根據或非門的(de)(de)(de)邏輯(ji)可(ke)得(de)兩個或非門的(de)(de)(de)輸出信號(hao)(hao)Va和Vb。由波形圖(tu)可(ke)以看(kan)出，PWM比較器的(de)(de)(de)反(fan)相(xiang)輸入(ru)端(duan)電(dian)(dian)平越高(gao)，輸出脈沖Va和Vb的(de)(de)(de)占(zhan)空(kong)比越大(da)(da)；反(fan)之越小(xiao)。根據這一規律(lv)來(lai)實現該控制器的(de)(de)(de)調壓、軟啟動及(ji)保護功能。另外，可(ke)以通過改變5腳和7腳之間的(de)(de)(de)外接電(dian)(dian)阻(zu)的(de)(de)(de)大(da)(da)小(xiao)，使(shi)時鐘(zhong)脈沖寬度變化來(lai)實現死區大(da)(da)小(xiao)的(de)(de)(de)調節(jie)[2]。

　　4 充電器(qi)的控制(zhi)與保(bao)護策略(lve)

　　航(hang)空(kong)蓄電(dian)(dian)(dian)池充電(dian)(dian)(dian)器(qi)(qi)的控(kong)制原理(li)框圖(tu)如圖(tu)4所(suo)示。芯(xin)片SG3525產生(sheng)的兩路(lu) PWM波經過光耦隔離以后，被送入IR2130從而驅動開關管工作，由于充電(dian)(dian)(dian)器(qi)(qi)的負載(zai)為電(dian)(dian)(dian)壓時刻變(bian)化的航(hang)空(kong)蓄電(dian)(dian)(dian)池，因此在(zai)控(kong)制電(dian)(dian)(dian)路(lu)中(zhong)還(huan)采用了電(dian)(dian)(dian)壓電(dian)(dian)(dian)流(liu)雙(shuang)閉環(huan)控(kong)制、過流(liu)及過溫(wen)保(bao)護電(dian)(dian)(dian)路(lu)，從而能保(bao)證充電(dian)(dian)(dian)器(qi)(qi)高效、可靠(kao)的完成整個(ge)充電(dian)(dian)(dian)過程(cheng)。

圖(tu)4 充電器控制原理(li)框圖(tu)

　　該充電器的工作過程可以簡單的描述為：當充電器檢測到蓄電池兩端的電壓低于某一定值電壓（第一定值）時，充電器開始工作并(bing)進(jin)入恒流(liu)充(chong)電(dian)(dian)(dian)(dian)(dian)狀態，此時由外部的電(dian)(dian)(dian)(dian)(dian)壓(ya)傳感器(qi)(qi)和電(dian)(dian)(dian)(dian)(dian)流(liu)傳感器(qi)(qi)采集來的電(dian)(dian)(dian)(dian)(dian)壓(ya)、電(dian)(dian)(dian)(dian)(dian)流(liu)信(xin)號傳送到控制電(dian)(dian)(dian)(dian)(dian)路進(jin)行電(dian)(dian)(dian)(dian)(dian)壓(ya)、電(dian)(dian)(dian)(dian)(dian)流(liu)雙閉環調節，保持充(chong)電(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)流(liu)恒定(ding)；當(dang)充(chong)電(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)壓(ya)達(da)到另一定(ding)值（第二定(ding)值）電(dian)(dian)(dian)(dian)(dian)壓(ya)時，蓄電(dian)(dian)(dian)(dian)(dian)池(chi)充(chong)電(dian)(dian)(dian)(dian)(dian)器(qi)(qi)進(jin)入涓流(liu)充(chong)電(dian)(dian)(dian)(dian)(dian)狀態，當(dang)蓄電(dian)(dian)(dian)(dian)(dian)池(chi)充(chong)電(dian)(dian)(dian)(dian)(dian)器(qi)(qi)檢測(ce)到蓄電(dian)(dian)(dian)(dian)(dian)池(chi)兩(liang)端電(dian)(dian)(dian)(dian)(dian)壓(ya)不再發生明顯變化時，充(chong)電(dian)(dian)(dian)(dian)(dian)過程結束。

　　5 軟件設計

　　單片機系統以AD公司的數據采集系統芯片ADuC812為核心，采用單片機C語言進行編程，該芯片以8951為內核，集成了高精度的多通道ADC和 DAC，具有在線可編程功能，該系統的主要功能是通過人機接口（按鍵，LED顯示）來設置對蓄電池的充電電流的大小，用采集到的電流和電壓值與設定值進行數字式PID調節，以控制D/A輸出，并在充電的過程中實時顯示蓄電池電壓、電流值和充電時間。
　　軟件設計的流程圖如圖5所示，在恒流充電階段，電壓傳感器產生的電壓信號、電流傳感器產生的電壓信號傳送到單片機以后，單片機產生2V的D/A信號給調理電路，在檢測到蓄電池兩端電壓達到第二定值時，充電器進入涓流充電階段，單片機電路產生較小的D/A值，使蓄電池以較小的電流充電(涓流充電)，當檢測到蓄電池電壓不再上升（或者發生明顯的變化）時，單片機電路給出關斷充電器信號，蓄電池充電過程結束。
 

圖(tu)5 充電器的軟件流程圖(tu)

　　6 試驗結果(guo)

圖(tu)6 蓄電池充電過(guo)程示(shi)意圖(tu)

　　使用(yong)該蓄(xu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)器(qi)對某型號航空蓄(xu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)進(jin)行(xing)了充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)試驗，最大充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)限制(zhi)為30A，溫(wen)度限制(zhi)值定為350C。蓄(xu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)的(de)(de)(de)初始電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)為20V，充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)開(kai)始時(shi)(shi)，充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)器(qi)以(yi)20A的(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)對蓄(xu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)持續充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)約(yue)58分(fen)鐘，然后以(yi)較小的(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)3A對蓄(xu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)進(jin)行(xing)涓流(liu)充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)，直至蓄(xu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)上(shang)升到32.45V時(shi)(shi)，蓄(xu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)兩端的(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)不再發生(sheng)明顯的(de)(de)(de)上(shang)升現象，此時(shi)(shi)充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)器(qi)停止充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)，歷時(shi)(shi)150分(fen)鐘，充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)過程曲線(xian)示意圖如圖6所示。

　　7 結論

　　本(ben)文提(ti)出了一種鎘鎳航(hang)空蓄電(dian)(dian)池充(chong)電(dian)(dian)器(qi)的(de)設計方(fang)(fang)案和控(kong)制原(yuan)理，精確(que)實(shi)(shi)現了恒(heng)流充(chong)電(dian)(dian)和涓流充(chong)電(dian)(dian)功(gong)能，該充(chong)電(dian)(dian)器(qi)實(shi)(shi)現了輸出與電(dian)(dian)網(wang)的(de)高(gao)頻電(dian)(dian)氣隔離，充(chong)電(dian)(dian)效(xiao)率高(gao)，使(shi)用(yong)(yong)方(fang)(fang)便，工作穩定(ding)，有效(xiao)地縮短了充(chong)電(dian)(dian)時(shi)間，提(ti)高(gao)了充(chong)電(dian)(dian)質(zhi)量，便于現場應用(yong)(yong)，滿足航(hang)空蓄電(dian)(dian)池的(de)使(shi)用(yong)(yong)要求，現已經裝備使(shi)用(yong)(yong)，效(xiao)果良好。