該航空蓄電池充電器為(wei)飛(fei)機某型號蓄(xu)電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)專門設計，主要實現兩階段充(chong)電(dian)(dian)(dian)(dian)(dian)(dian)功(gong)能，即(ji)恒流(liu)充(chong)電(dian)(dian)(dian)(dian)(dian)(dian)狀態（以(yi)20A的(de)大電(dian)(dian)(dian)(dian)(dian)(dian)流(liu)充(chong)電(dian)(dian)(dian)(dian)(dian)(dian)）和涓流(liu)充(chong)電(dian)(dian)(dian)(dian)(dian)(dian)狀態（以(yi)3A的(de)小電(dian)(dian)(dian)(dian)(dian)(dian)流(liu)充(chong)電(dian)(dian)(dian)(dian)(dian)(dian)）。蓄(xu)電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)充(chong)電(dian)(dian)(dian)(dian)(dian)(dian)器使用的(de)工作電(dian)(dian)(dian)(dian)(dian)(dian)源為(wei)115V/400Hz的(de)航空電(dian)(dian)(dian)(dian)(dian)(dian)源，充(chong)電(dian)(dian)(dian)(dian)(dian)(dian)器能在(zai)1小時內完成恒流(liu)充(chong)電(dian)(dian)(dian)(dian)(dian)(dian)，隨后以(yi)涓流(liu)狀態對蓄(xu)電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)組進行充(chong)電(dian)(dian)(dian)(dian)(dian)(dian)直至充(chong)電(dian)(dian)(dian)(dian)(dian)(dian)結束，每個充(chong)電(dian)(dian)(dian)(dian)(dian)(dian)過程在(zai)2個小時內完成。

　　2　充電器總體設計方案
 
 　　航空蓄電(dian)池充(chong)(chong)電(dian)器(qi)的(de)(de)主電(dian)路(lu)如圖1所示，電(dian)源(yuan)變(bian)換(huan)器(qi)采用(yong)了(le)由半橋變(bian)換(huan)器(qi)、高(gao)頻變(bian)壓器(qi)和輸出(chu)整流濾波電(dian)路(lu)組成的(de)(de)半橋變(bian)換(huan)器(qi)[1]，該(gai)電(dian)路(lu)結構簡單，工(gong)作可(ke)(ke)靠，功率(lv)(lv)管為(wei)場(chang)效(xiao)應管，而且開關(guan)(guan)管承受的(de)(de)電(dian)壓為(wei)電(dian)源(yuan)電(dian)壓，故(gu)可(ke)(ke)在電(dian)源(yuan)電(dian)壓較高(gao)的(de)(de)場(chang)合應用(yong)。通常高(gao)頻大功率(lv)(lv)變(bian)換(huan)器(qi)開關(guan)(guan)頻率(lv)(lv)一般都(dou)大于15kHz，為(wei)了(le)使(shi)功率(lv)(lv)電(dian)路(lu)小型化、減小失真并(bing)保持(chi)高(gao)的(de)(de)變(bian)換(huan)效(xiao)率(lv)(lv)，該(gai)充(chong)(chong)電(dian)器(qi)采用(yong)了(le)20kHz的(de)(de)開關(guan)(guan)頻率(lv)(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(tu)3 SG3525芯片(pian)各點的工作波形

 　　SG3525芯片各點(dian)的(de)工作波形(xing)如圖3所示，由誤差放大(da)(da)器(qi)輸(shu)出的(de)電壓(ya)Ve與(yu)鋸齒波的(de)交點(dian)可(ke)得一負的(de)PWM信號。由PWM信號、時鐘信號及分相(xiang)器(qi)輸(shu)出的(de)Q (或(huo) )信號，根據(ju)或(huo)非(fei)門(men)的(de)邏輯(ji)可(ke)得兩個(ge)或(huo)非(fei)門(men)的(de)輸(shu)出信號Va和(he)Vb。由波形(xing)圖可(ke)以(yi)看出，PWM比(bi)較器(qi)的(de)反相(xiang)輸(shu)入(ru)端電平越高(gao)，輸(shu)出脈沖Va和(he)Vb的(de)占(zhan)空比(bi)越大(da)(da)；反之越小(xiao)(xiao)。根據(ju)這一規律來實現該控制器(qi)的(de)調(diao)壓(ya)、軟(ruan)啟動及保護功能。另外，可(ke)以(yi)通過改(gai)變5腳和(he)7腳之間的(de)外接電阻的(de)大(da)(da)小(xiao)(xiao)，使時鐘脈沖寬(kuan)度變化來實現死區(qu)大(da)(da)小(xiao)(xiao)的(de)調(diao)節[2]。

　　4 充電器的控制與保護策略

　　航空蓄(xu)電(dian)(dian)(dian)池充(chong)電(dian)(dian)(dian)器(qi)的(de)控制原理框圖(tu)如圖(tu)4所示(shi)。芯片SG3525產生的(de)兩路 PWM波(bo)經過(guo)光耦(ou)隔離以后，被送入IR2130從而驅動(dong)開關管工(gong)作，由于充(chong)電(dian)(dian)(dian)器(qi)的(de)負載為電(dian)(dian)(dian)壓時刻變化的(de)航空蓄(xu)電(dian)(dian)(dian)池，因此在(zai)控制電(dian)(dian)(dian)路中還(huan)采用了電(dian)(dian)(dian)壓電(dian)(dian)(dian)流雙閉環控制、過(guo)流及過(guo)溫保(bao)護電(dian)(dian)(dian)路，從而能保(bao)證充(chong)電(dian)(dian)(dian)器(qi)高效、可靠(kao)的(de)完成(cheng)整個充(chong)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(ce)到蓄電池(chi)兩端電壓不(bu)再發生明顯變化時，充電過(guo)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。
  使用該蓄電(dian)(dian)(dian)(dian)池(chi)充(chong)(chong)電(dian)(dian)(dian)(dian)器(qi)對某型號航(hang)空蓄電(dian)(dian)(dian)(dian)池(chi)進行(xing)了充(chong)(chong)電(dian)(dian)(dian)(dian)試驗，最大充(chong)(chong)電(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)流(liu)限制(zhi)為30A，溫度(du)限制(zhi)值定(ding)為350C。蓄電(dian)(dian)(dian)(dian)池(chi)的(de)(de)初始(shi)電(dian)(dian)(dian)(dian)壓為20V，充(chong)(chong)電(dian)(dian)(dian)(dian)開始(shi)時(shi)(shi)，充(chong)(chong)電(dian)(dian)(dian)(dian)器(qi)以(yi)(yi)20A的(de)(de)電(dian)(dian)(dian)(dian)流(liu)對蓄電(dian)(dian)(dian)(dian)池(chi)持續充(chong)(chong)電(dian)(dian)(dian)(dian)約(yue)58分(fen)鐘，然后以(yi)(yi)較小的(de)(de)電(dian)(dian)(dian)(dian)流(liu)3A對蓄電(dian)(dian)(dian)(dian)池(chi)進行(xing)涓流(liu)充(chong)(chong)電(dian)(dian)(dian)(dian)，直(zhi)至蓄電(dian)(dian)(dian)(dian)池(chi)電(dian)(dian)(dian)(dian)壓上升(sheng)到32.45V時(shi)(shi)，蓄電(dian)(dian)(dian)(dian)池(chi)兩端的(de)(de)電(dian)(dian)(dian)(dian)壓不再發生明顯(xian)的(de)(de)上升(sheng)現(xian)象，此時(shi)(shi)充(chong)(chong)電(dian)(dian)(dian)(dian)器(qi)停止充(chong)(chong)電(dian)(dian)(dian)(dian)，歷時(shi)(shi)150分(fen)鐘。

　　本文提出了一種鎘鎳航空蓄電池充電器的(de)設(she)計方(fang)案和控制原理，精確(que)實(shi)(shi)現(xian)(xian)了恒(heng)流(liu)充(chong)電和涓流(liu)充(chong)電功能(neng)，該充(chong)電器實(shi)(shi)現(xian)(xian)了輸(shu)出與電網(wang)的(de)高(gao)(gao)頻電氣隔離，充(chong)電效率(lv)高(gao)(gao)，使用(yong)(yong)方(fang)便，工作穩(wen)定，有效地縮短了充(chong)電時間(jian)，提高(gao)(gao)了充(chong)電質量(liang)，便于現(xian)(xian)場應(ying)用(yong)(yong)，滿足航空蓄(xu)電池(chi)的(de)使用(yong)(yong)要求，現(xian)(xian)已經(jing)裝備使用(yong)(yong)，效果良(liang)好。