該航空蓄電池充電器為飛(fei)機某(mou)型號蓄(xu)電(dian)(dian)(dian)(dian)池專(zhuan)門設計，主要實現兩階段充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)功能，即恒(heng)流(liu)充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)狀(zhuang)態(tai)（以20A的(de)(de)大電(dian)(dian)(dian)(dian)流(liu)充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)）和涓流(liu)充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)狀(zhuang)態(tai)（以3A的(de)(de)小電(dian)(dian)(dian)(dian)流(liu)充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)）。蓄(xu)電(dian)(dian)(dian)(dian)池充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)器(qi)使用的(de)(de)工作電(dian)(dian)(dian)(dian)源為115V/400Hz的(de)(de)航(hang)空電(dian)(dian)(dian)(dian)源，充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)器(qi)能在1小時(shi)(shi)內完(wan)成恒(heng)流(liu)充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)，隨后以涓流(liu)狀(zhuang)態(tai)對(dui)蓄(xu)電(dian)(dian)(dian)(dian)池組進(jin)行充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)直(zhi)至充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)結束，每個充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)過程在2個小時(shi)(shi)內完(wan)成。

　　2　充電器總體設計方案
 
 　　航空蓄電(dian)(dian)池(chi)充(chong)電(dian)(dian)器的主(zhu)電(dian)(dian)路(lu)如圖1所示，電(dian)(dian)源(yuan)變(bian)換器采用了(le)由半橋(qiao)變(bian)換器、高頻(pin)(pin)變(bian)壓(ya)器和(he)輸出整流濾波(bo)電(dian)(dian)路(lu)組(zu)成的半橋(qiao)變(bian)換器[1]，該(gai)電(dian)(dian)路(lu)結構(gou)簡單，工(gong)作可(ke)靠，功率(lv)管(guan)為場(chang)效應(ying)管(guan)，而且(qie)開(kai)關(guan)管(guan)承受的電(dian)(dian)壓(ya)為電(dian)(dian)源(yuan)電(dian)(dian)壓(ya)，故可(ke)在電(dian)(dian)源(yuan)電(dian)(dian)壓(ya)較高的場(chang)合應(ying)用。通常(chang)高頻(pin)(pin)大(da)功率(lv)變(bian)換器開(kai)關(guan)頻(pin)(pin)率(lv)一般都大(da)于15kHz，為了(le)使功率(lv)電(dian)(dian)路(lu)小型化、減小失真并保持高的變(bian)換效率(lv)，該(gai)充(chong)電(dian)(dian)器采用了(le)20kHz的開(kai)關(guan)頻(pin)(pin)率(lv)。

　　3 SG3525芯片介紹
 
　　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(pian)各點的工作波形

 　　SG3525芯(xin)片(pian)各(ge)點的(de)(de)工(gong)作波(bo)(bo)形如圖3所示，由誤差放大器(qi)(qi)(qi)輸(shu)出(chu)的(de)(de)電壓Ve與鋸齒波(bo)(bo)的(de)(de)交點可(ke)得一負的(de)(de)PWM信(xin)(xin)號(hao)(hao)。由PWM信(xin)(xin)號(hao)(hao)、時(shi)鐘(zhong)信(xin)(xin)號(hao)(hao)及分(fen)相(xiang)器(qi)(qi)(qi)輸(shu)出(chu)的(de)(de)Q (或(huo) )信(xin)(xin)號(hao)(hao)，根(gen)據或(huo)非(fei)門的(de)(de)邏輯可(ke)得兩個或(huo)非(fei)門的(de)(de)輸(shu)出(chu)信(xin)(xin)號(hao)(hao)Va和(he)Vb。由波(bo)(bo)形圖可(ke)以看出(chu)，PWM比較器(qi)(qi)(qi)的(de)(de)反相(xiang)輸(shu)入端電平越高，輸(shu)出(chu)脈(mo)沖Va和(he)Vb的(de)(de)占空比越大；反之越小。根(gen)據這(zhe)一規律來實(shi)現該控制器(qi)(qi)(qi)的(de)(de)調(diao)壓、軟啟動及保(bao)護功能。另(ling)外(wai)，可(ke)以通過(guo)改變(bian)5腳和(he)7腳之間的(de)(de)外(wai)接(jie)電阻(zu)的(de)(de)大小，使時(shi)鐘(zhong)脈(mo)沖寬度變(bian)化來實(shi)現死區大小的(de)(de)調(diao)節(jie)[2]。

　　4 充電器的控制與保護策略

　　航空蓄電(dian)(dian)(dian)池(chi)充電(dian)(dian)(dian)器的(de)控制(zhi)原(yuan)理框圖如圖4所(suo)示。芯(xin)片SG3525產生(sheng)的(de)兩路 PWM波經過(guo)光耦隔(ge)離以后，被送入IR2130從而驅動開關(guan)管工作，由于充電(dian)(dian)(dian)器的(de)負(fu)載為電(dian)(dian)(dian)壓時刻變化的(de)航空蓄電(dian)(dian)(dian)池(chi)，因(yin)此在控制(zhi)電(dian)(dian)(dian)路中還采用(yong)了電(dian)(dian)(dian)壓電(dian)(dian)(dian)流(liu)雙閉環控制(zhi)、過(guo)流(liu)及過(guo)溫保(bao)護電(dian)(dian)(dian)路，從而能保(bao)證充電(dian)(dian)(dian)器高效、可靠的(de)完成整個充電(dian)(dian)(dian)過(guo)程。     

   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入恒流充電狀態，此時由外部的電壓傳感器和電流傳感器采集來的電壓、電流信號傳送到控制電路進行電壓、電流雙閉環調節，保持充電電流恒定；當充電電壓達到另一定值（第二定值）電壓時，蓄電池充電器進入涓流充電狀態，當蓄電池充電器檢測到蓄電(dian)(dian)池兩端(duan)電(dian)(dian)壓不(bu)再發生(sheng)明顯變化時，充電(dian)(dian)過程結束。

　 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。
  使用(yong)該蓄(xu)(xu)電(dian)(dian)(dian)(dian)(dian)(dian)池充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)器(qi)對(dui)某型號(hao)航空蓄(xu)(xu)電(dian)(dian)(dian)(dian)(dian)(dian)池進行(xing)了充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)試驗，最大充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)流(liu)限制為30A，溫度限制值定(ding)為350C。蓄(xu)(xu)電(dian)(dian)(dian)(dian)(dian)(dian)池的(de)(de)(de)初始電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)為20V，充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)開始時，充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)器(qi)以20A的(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)流(liu)對(dui)蓄(xu)(xu)電(dian)(dian)(dian)(dian)(dian)(dian)池持續充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)約58分鐘(zhong)，然后以較(jiao)小的(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)流(liu)3A對(dui)蓄(xu)(xu)電(dian)(dian)(dian)(dian)(dian)(dian)池進行(xing)涓流(liu)充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)，直至蓄(xu)(xu)電(dian)(dian)(dian)(dian)(dian)(dian)池電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)上升到32.45V時，蓄(xu)(xu)電(dian)(dian)(dian)(dian)(dian)(dian)池兩端的(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)不再發生明顯的(de)(de)(de)上升現象，此時充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)器(qi)停止充(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)，歷時150分鐘(zhong)。

　　本文提出了一種鎘鎳航空蓄電池充電器的設(she)計方案和(he)控制原理，精確實現(xian)了恒流充(chong)(chong)電(dian)和(he)涓流充(chong)(chong)電(dian)功能，該充(chong)(chong)電(dian)器(qi)實現(xian)了輸(shu)出(chu)與電(dian)網的高頻電(dian)氣隔離，充(chong)(chong)電(dian)效(xiao)率高，使(shi)用(yong)方便(bian)，工作(zuo)穩定，有效(xiao)地(di)縮短了充(chong)(chong)電(dian)時(shi)間，提高了充(chong)(chong)電(dian)質量，便(bian)于現(xian)場應用(yong)，滿足航空蓄電(dian)池(chi)的使(shi)用(yong)要求，現(xian)已經(jing)裝備(bei)使(shi)用(yong)，效(xiao)果良好(hao)。