該航空蓄電池充電器為(wei)(wei)飛(fei)機某型(xing)號蓄電(dian)(dian)(dian)(dian)(dian)池(chi)(chi)專門設計，主要(yao)實(shi)現兩階段充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)功能，即恒(heng)流(liu)充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)狀態(tai)（以20A的(de)(de)大電(dian)(dian)(dian)(dian)(dian)流(liu)充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)）和涓流(liu)充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)狀態(tai)（以3A的(de)(de)小電(dian)(dian)(dian)(dian)(dian)流(liu)充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)）。蓄電(dian)(dian)(dian)(dian)(dian)池(chi)(chi)充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)器使用的(de)(de)工作電(dian)(dian)(dian)(dian)(dian)源為(wei)(wei)115V/400Hz的(de)(de)航空電(dian)(dian)(dian)(dian)(dian)源，充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)器能在(zai)1小時(shi)內完成恒(heng)流(liu)充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)，隨后以涓流(liu)狀態(tai)對蓄電(dian)(dian)(dian)(dian)(dian)池(chi)(chi)組進行充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)直(zhi)至充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)結(jie)束，每個充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)過程在(zai)2個小時(shi)內完成。

　　2　充電器總體設計方案
 
 　　航空蓄電(dian)(dian)(dian)池充電(dian)(dian)(dian)器(qi)的(de)(de)主電(dian)(dian)(dian)路如圖(tu)1所示，電(dian)(dian)(dian)源(yuan)變(bian)換器(qi)采用(yong)了由(you)半橋(qiao)變(bian)換器(qi)、高(gao)頻(pin)變(bian)壓(ya)器(qi)和輸出整流(liu)濾(lv)波電(dian)(dian)(dian)路組(zu)成(cheng)的(de)(de)半橋(qiao)變(bian)換器(qi)[1]，該電(dian)(dian)(dian)路結(jie)構簡單，工作可(ke)靠(kao)，功(gong)率(lv)(lv)管為場(chang)效(xiao)應管，而且開(kai)關管承受的(de)(de)電(dian)(dian)(dian)壓(ya)為電(dian)(dian)(dian)源(yuan)電(dian)(dian)(dian)壓(ya)，故可(ke)在電(dian)(dian)(dian)源(yuan)電(dian)(dian)(dian)壓(ya)較(jiao)高(gao)的(de)(de)場(chang)合應用(yong)。通常高(gao)頻(pin)大(da)功(gong)率(lv)(lv)變(bian)換器(qi)開(kai)關頻(pin)率(lv)(lv)一般都大(da)于15kHz，為了使功(gong)率(lv)(lv)電(dian)(dian)(dian)路小型化(hua)、減小失(shi)真并(bing)保持高(gao)的(de)(de)變(bian)換效(xiao)率(lv)(lv)，該充電(dian)(dian)(dian)器(qi)采用(yong)了20kHz的(de)(de)開(kai)關頻(pin)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3 SG3525芯片(pian)各點的(de)工(gong)作波形

 　　SG3525芯片各點(dian)的(de)(de)(de)(de)(de)工(gong)作波(bo)(bo)形(xing)如(ru)圖(tu)3所示(shi)，由誤差放大(da)器輸(shu)(shu)出的(de)(de)(de)(de)(de)電壓Ve與鋸齒(chi)波(bo)(bo)的(de)(de)(de)(de)(de)交點(dian)可(ke)得(de)一(yi)負(fu)的(de)(de)(de)(de)(de)PWM信號(hao)(hao)(hao)。由PWM信號(hao)(hao)(hao)、時(shi)鐘信號(hao)(hao)(hao)及分相(xiang)器輸(shu)(shu)出的(de)(de)(de)(de)(de)Q (或(huo) )信號(hao)(hao)(hao)，根據或(huo)非門的(de)(de)(de)(de)(de)邏輯(ji)可(ke)得(de)兩個(ge)或(huo)非門的(de)(de)(de)(de)(de)輸(shu)(shu)出信號(hao)(hao)(hao)Va和(he)Vb。由波(bo)(bo)形(xing)圖(tu)可(ke)以看出，PWM比較器的(de)(de)(de)(de)(de)反(fan)相(xiang)輸(shu)(shu)入端電平越(yue)(yue)高，輸(shu)(shu)出脈(mo)沖(chong)Va和(he)Vb的(de)(de)(de)(de)(de)占空比越(yue)(yue)大(da)；反(fan)之(zhi)越(yue)(yue)小。根據這一(yi)規律來實(shi)現(xian)(xian)該(gai)控制器的(de)(de)(de)(de)(de)調壓、軟啟(qi)動及保護(hu)功能。另(ling)外(wai)，可(ke)以通過改變(bian)5腳和(he)7腳之(zhi)間的(de)(de)(de)(de)(de)外(wai)接電阻的(de)(de)(de)(de)(de)大(da)小，使時(shi)鐘脈(mo)沖(chong)寬(kuan)度變(bian)化(hua)來實(shi)現(xian)(xian)死區大(da)小的(de)(de)(de)(de)(de)調節[2]。

　　4 充電器的控制與保護策略

　　航空蓄電(dian)(dian)(dian)池充電(dian)(dian)(dian)器的控制(zhi)原理框(kuang)圖如圖4所示。芯(xin)片(pian)SG3525產(chan)生的兩路(lu)(lu) PWM波經過(guo)光耦隔離以后，被送入IR2130從(cong)而驅動開(kai)關管(guan)工作，由(you)于充電(dian)(dian)(dian)器的負載為電(dian)(dian)(dian)壓時刻變化的航空蓄電(dian)(dian)(dian)池，因此在控制(zhi)電(dian)(dian)(dian)路(lu)(lu)中還采用了電(dian)(dian)(dian)壓電(dian)(dian)(dian)流(liu)雙閉環控制(zhi)、過(guo)流(liu)及(ji)過(guo)溫保護電(dian)(dian)(dian)路(lu)(lu)，從(cong)而能保證(zheng)充電(dian)(dian)(dian)器高效、可靠的完(wan)成整個充電(dian)(dian)(dian)過(guo)程(cheng)。     

   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(dao)蓄電池兩端電壓不(bu)再發生明顯變(bian)化時，充電過程結束。

　 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。
  使用該蓄(xu)電(dian)(dian)(dian)(dian)(dian)池充(chong)電(dian)(dian)(dian)(dian)(dian)器(qi)對某型號航空(kong)蓄(xu)電(dian)(dian)(dian)(dian)(dian)池進(jin)行了充(chong)電(dian)(dian)(dian)(dian)(dian)試驗，最大充(chong)電(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)流限制為30A，溫度限制值定為350C。蓄(xu)電(dian)(dian)(dian)(dian)(dian)池的(de)初始電(dian)(dian)(dian)(dian)(dian)壓(ya)為20V，充(chong)電(dian)(dian)(dian)(dian)(dian)開(kai)始時(shi)，充(chong)電(dian)(dian)(dian)(dian)(dian)器(qi)以20A的(de)電(dian)(dian)(dian)(dian)(dian)流對蓄(xu)電(dian)(dian)(dian)(dian)(dian)池持續充(chong)電(dian)(dian)(dian)(dian)(dian)約(yue)58分(fen)鐘，然后以較小(xiao)的(de)電(dian)(dian)(dian)(dian)(dian)流3A對蓄(xu)電(dian)(dian)(dian)(dian)(dian)池進(jin)行涓(juan)流充(chong)電(dian)(dian)(dian)(dian)(dian)，直至蓄(xu)電(dian)(dian)(dian)(dian)(dian)池電(dian)(dian)(dian)(dian)(dian)壓(ya)上升(sheng)到32.45V時(shi)，蓄(xu)電(dian)(dian)(dian)(dian)(dian)池兩端(duan)的(de)電(dian)(dian)(dian)(dian)(dian)壓(ya)不再發(fa)生(sheng)明(ming)顯的(de)上升(sheng)現象，此(ci)時(shi)充(chong)電(dian)(dian)(dian)(dian)(dian)器(qi)停止充(chong)電(dian)(dian)(dian)(dian)(dian)，歷時(shi)150分(fen)鐘。

　　本文提出了一種鎘鎳航空蓄電池充電器的(de)(de)設計(ji)方(fang)(fang)案和(he)控(kong)制原(yuan)理，精(jing)確實(shi)現(xian)了(le)恒流充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)和(he)涓流充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)功能，該充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)器(qi)實(shi)現(xian)了(le)輸(shu)出與電(dian)(dian)(dian)(dian)網的(de)(de)高頻(pin)電(dian)(dian)(dian)(dian)氣(qi)隔離，充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)效(xiao)(xiao)率高，使用方(fang)(fang)便，工作穩定，有效(xiao)(xiao)地縮(suo)短了(le)充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)時(shi)間，提高了(le)充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)質量，便于現(xian)場應用，滿足航空蓄電(dian)(dian)(dian)(dian)池(chi)的(de)(de)使用要求，現(xian)已經裝備使用，效(xiao)(xiao)果良好。