1 引言

　　該航空蓄電池充電器為飛機某型號蓄電(dian)(dian)(dian)池(chi)(chi)專門(men)設(she)計(ji)，主要實(shi)現(xian)兩(liang)階(jie)段充(chong)(chong)(chong)電(dian)(dian)(dian)功(gong)能，即恒流充(chong)(chong)(chong)電(dian)(dian)(dian)狀(zhuang)態（以(yi)20A的(de)大電(dian)(dian)(dian)流充(chong)(chong)(chong)電(dian)(dian)(dian)）和涓流充(chong)(chong)(chong)電(dian)(dian)(dian)狀(zhuang)態（以(yi)3A的(de)小(xiao)電(dian)(dian)(dian)流充(chong)(chong)(chong)電(dian)(dian)(dian)）。蓄電(dian)(dian)(dian)池(chi)(chi)充(chong)(chong)(chong)電(dian)(dian)(dian)器使用(yong)的(de)工作電(dian)(dian)(dian)源(yuan)為115V/400Hz的(de)航空(kong)電(dian)(dian)(dian)源(yuan)，充(chong)(chong)(chong)電(dian)(dian)(dian)器能在(zai)(zai)1小(xiao)時(shi)內完(wan)成(cheng)恒流充(chong)(chong)(chong)電(dian)(dian)(dian)，隨后(hou)以(yi)涓流狀(zhuang)態對(dui)蓄電(dian)(dian)(dian)池(chi)(chi)組(zu)進行(xing)充(chong)(chong)(chong)電(dian)(dian)(dian)直至充(chong)(chong)(chong)電(dian)(dian)(dian)結束，每個充(chong)(chong)(chong)電(dian)(dian)(dian)過(guo)程在(zai)(zai)2個小(xiao)時(shi)內完(wan)成(cheng)。

　　2　充電器總體設計方案
 

圖1 充(chong)電器主(zhu)電路結構框圖

 　　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，該充電器采用了20kHz的開關頻率。

　　3 SG3525芯片介紹
 

圖2　SG3525芯片的結構圖

　　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(xin)片各點的工(gong)作波(bo)形

 　　SG3525芯(xin)片各點的(de)(de)(de)工(gong)作波(bo)形(xing)(xing)如(ru)圖3所示，由誤(wu)差放大(da)器輸出的(de)(de)(de)電(dian)壓(ya)Ve與鋸(ju)齒波(bo)的(de)(de)(de)交點可得一(yi)負的(de)(de)(de)PWM信(xin)(xin)號(hao)。由PWM信(xin)(xin)號(hao)、時(shi)鐘信(xin)(xin)號(hao)及(ji)分相(xiang)器輸出的(de)(de)(de)Q (或 )信(xin)(xin)號(hao)，根(gen)據(ju)或非門的(de)(de)(de)邏輯可得兩(liang)個或非門的(de)(de)(de)輸出信(xin)(xin)號(hao)Va和Vb。由波(bo)形(xing)(xing)圖可以(yi)看出，PWM比(bi)較器的(de)(de)(de)反(fan)相(xiang)輸入端電(dian)平越高，輸出脈沖Va和Vb的(de)(de)(de)占空比(bi)越大(da)；反(fan)之越小(xiao)(xiao)。根(gen)據(ju)這一(yi)規(gui)律來實(shi)現該控制器的(de)(de)(de)調壓(ya)、軟啟動(dong)及(ji)保護功能(neng)。另外，可以(yi)通過改變5腳(jiao)和7腳(jiao)之間(jian)的(de)(de)(de)外接電(dian)阻的(de)(de)(de)大(da)小(xiao)(xiao)，使(shi)時(shi)鐘脈沖寬(kuan)度變化(hua)來實(shi)現死區(qu)大(da)小(xiao)(xiao)的(de)(de)(de)調節[2]。

　　4 充(chong)電器(qi)的控制(zhi)與保護策略(lve)

　　航(hang)空蓄(xu)電(dian)(dian)(dian)(dian)(dian)池(chi)充電(dian)(dian)(dian)(dian)(dian)器的(de)(de)控制原(yuan)理(li)框圖如圖4所(suo)示。芯片SG3525產生(sheng)的(de)(de)兩路(lu) PWM波經過(guo)光耦隔離以(yi)后，被(bei)送入IR2130從(cong)而(er)驅動開關(guan)管工作，由于充電(dian)(dian)(dian)(dian)(dian)器的(de)(de)負(fu)載為電(dian)(dian)(dian)(dian)(dian)壓時刻變化的(de)(de)航(hang)空蓄(xu)電(dian)(dian)(dian)(dian)(dian)池(chi)，因(yin)此在控制電(dian)(dian)(dian)(dian)(dian)路(lu)中還采(cai)用了電(dian)(dian)(dian)(dian)(dian)壓電(dian)(dian)(dian)(dian)(dian)流雙閉環控制、過(guo)流及過(guo)溫保護電(dian)(dian)(dian)(dian)(dian)路(lu)，從(cong)而(er)能保證充電(dian)(dian)(dian)(dian)(dian)器高效、可靠的(de)(de)完成整個充電(dian)(dian)(dian)(dian)(dian)過(guo)程。

圖4 充電器控制(zhi)原理框圖

　　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，充電器開始工作并進(jin)入恒流(liu)充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)狀態，此時由外部的電(dian)(dian)(dian)(dian)(dian)壓(ya)傳(chuan)感器(qi)(qi)和電(dian)(dian)(dian)(dian)(dian)流(liu)傳(chuan)感器(qi)(qi)采集來(lai)的電(dian)(dian)(dian)(dian)(dian)壓(ya)、電(dian)(dian)(dian)(dian)(dian)流(liu)信號傳(chuan)送(song)到(dao)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(shuang)閉環調節，保(bao)持充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)流(liu)恒定(ding)；當充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)壓(ya)達到(dao)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)(chong)電(dian)(dian)(dian)(dian)(dian)器(qi)(qi)進(jin)入涓流(liu)充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)狀態，當蓄電(dian)(dian)(dian)(dian)(dian)池(chi)充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)器(qi)(qi)檢測到(dao)蓄電(dian)(dian)(dian)(dian)(dian)池(chi)兩(liang)端(duan)電(dian)(dian)(dian)(dian)(dian)壓(ya)不再發生明(ming)顯變化時，充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)過(guo)程結(jie)束(shu)。

　　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(qi)的軟件流程圖(tu)

　　6 試驗(yan)結果

圖6 蓄電(dian)池充電(dian)過程(cheng)示(shi)意圖

　　使(shi)用該(gai)蓄(xu)(xu)(xu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)器(qi)對某(mou)型號(hao)航空蓄(xu)(xu)(xu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)進(jin)行了充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)試驗，最(zui)大充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)限(xian)制為(wei)30A，溫度限(xian)制值(zhi)定為(wei)350C。蓄(xu)(xu)(xu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)的(de)(de)初始電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)為(wei)20V，充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)開始時(shi)，充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)器(qi)以20A的(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)對蓄(xu)(xu)(xu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)持(chi)續充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)約58分(fen)鐘，然后(hou)以較(jiao)小(xiao)的(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)3A對蓄(xu)(xu)(xu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)進(jin)行涓流(liu)充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)，直至(zhi)蓄(xu)(xu)(xu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)上(shang)升到32.45V時(shi)，蓄(xu)(xu)(xu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)兩端(duan)的(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)不再發生明顯的(de)(de)上(shang)升現(xian)象，此時(shi)充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)器(qi)停止(zhi)充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)，歷時(shi)150分(fen)鐘，充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)過程曲線示意圖如圖6所示。

　　7 結論

　　本文提出了(le)一種鎘鎳航空蓄(xu)電(dian)(dian)(dian)(dian)池充(chong)電(dian)(dian)(dian)(dian)器的(de)設計(ji)方(fang)案和(he)(he)控制原理，精確(que)實現了(le)恒流充(chong)電(dian)(dian)(dian)(dian)和(he)(he)涓流充(chong)電(dian)(dian)(dian)(dian)功(gong)能，該(gai)充(chong)電(dian)(dian)(dian)(dian)器實現了(le)輸出與電(dian)(dian)(dian)(dian)網的(de)高(gao)頻電(dian)(dian)(dian)(dian)氣隔離，充(chong)電(dian)(dian)(dian)(dian)效(xiao)(xiao)率高(gao)，使(shi)用方(fang)便(bian)，工作穩定，有效(xiao)(xiao)地(di)縮短了(le)充(chong)電(dian)(dian)(dian)(dian)時間(jian)，提高(gao)了(le)充(chong)電(dian)(dian)(dian)(dian)質量，便(bian)于現場(chang)應用，滿足航空蓄(xu)電(dian)(dian)(dian)(dian)池的(de)使(shi)用要求，現已經裝備使(shi)用，效(xiao)(xiao)果良好。