該航空蓄電池充電器為飛(fei)機某(mou)型(xing)號蓄電(dian)(dian)(dian)(dian)(dian)池(chi)(chi)專門設計，主要實現兩階段(duan)充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)功(gong)能，即(ji)恒流(liu)(liu)充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)狀(zhuang)態(tai)（以20A的(de)大(da)電(dian)(dian)(dian)(dian)(dian)流(liu)(liu)充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)）和涓(juan)(juan)流(liu)(liu)充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)狀(zhuang)態(tai)（以3A的(de)小(xiao)電(dian)(dian)(dian)(dian)(dian)流(liu)(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(qi)(qi)使用的(de)工(gong)作電(dian)(dian)(dian)(dian)(dian)源為115V/400Hz的(de)航空電(dian)(dian)(dian)(dian)(dian)源，充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)器(qi)(qi)能在1小(xiao)時(shi)內(nei)完成恒流(liu)(liu)充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)，隨(sui)后以涓(juan)(juan)流(liu)(liu)狀(zhuang)態(tai)對蓄電(dian)(dian)(dian)(dian)(dian)池(chi)(chi)組進(jin)行(xing)充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)直至充(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2個小(xiao)時(shi)內(nei)完成。

　　2　充電器總體設計方案
 
 　　航空(kong)蓄電(dian)(dian)(dian)(dian)池充(chong)電(dian)(dian)(dian)(dian)器(qi)(qi)(qi)的(de)主電(dian)(dian)(dian)(dian)路(lu)(lu)如(ru)圖1所示(shi)，電(dian)(dian)(dian)(dian)源變(bian)換(huan)(huan)(huan)器(qi)(qi)(qi)采用(yong)(yong)了(le)由(you)半橋變(bian)換(huan)(huan)(huan)器(qi)(qi)(qi)、高(gao)頻變(bian)壓(ya)(ya)器(qi)(qi)(qi)和輸出整流濾波電(dian)(dian)(dian)(dian)路(lu)(lu)組成的(de)半橋變(bian)換(huan)(huan)(huan)器(qi)(qi)(qi)[1]，該電(dian)(dian)(dian)(dian)路(lu)(lu)結構簡單，工作(zuo)可靠，功(gong)(gong)(gong)率(lv)管為場(chang)效應(ying)管，而且開(kai)關(guan)(guan)(guan)管承受的(de)電(dian)(dian)(dian)(dian)壓(ya)(ya)為電(dian)(dian)(dian)(dian)源電(dian)(dian)(dian)(dian)壓(ya)(ya)，故(gu)可在電(dian)(dian)(dian)(dian)源電(dian)(dian)(dian)(dian)壓(ya)(ya)較高(gao)的(de)場(chang)合應(ying)用(yong)(yong)。通(tong)常高(gao)頻大(da)功(gong)(gong)(gong)率(lv)變(bian)換(huan)(huan)(huan)器(qi)(qi)(qi)開(kai)關(guan)(guan)(guan)頻率(lv)一般(ban)都大(da)于15kHz，為了(le)使(shi)功(gong)(gong)(gong)率(lv)電(dian)(dian)(dian)(dian)路(lu)(lu)小型化、減(jian)小失真并保持高(gao)的(de)變(bian)換(huan)(huan)(huan)效率(lv)，該充(chong)電(dian)(dian)(dian)(dian)器(qi)(qi)(qi)采用(yong)(yong)了(le)20kHz的(de)開(kai)關(guan)(guan)(guan)頻率(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芯片各點的工作波形(xing)

 　　SG3525芯片各點(dian)(dian)的(de)(de)工(gong)作(zuo)波(bo)形如圖(tu)3所示，由誤差放大(da)器(qi)輸(shu)(shu)出的(de)(de)電(dian)壓Ve與鋸齒波(bo)的(de)(de)交點(dian)(dian)可得(de)一負的(de)(de)PWM信號(hao)。由PWM信號(hao)、時鐘(zhong)信號(hao)及(ji)分相器(qi)輸(shu)(shu)出的(de)(de)Q (或(huo)(huo) )信號(hao)，根據或(huo)(huo)非門的(de)(de)邏輯可得(de)兩(liang)個(ge)或(huo)(huo)非門的(de)(de)輸(shu)(shu)出信號(hao)Va和(he)Vb。由波(bo)形圖(tu)可以看出，PWM比(bi)較器(qi)的(de)(de)反相輸(shu)(shu)入(ru)端電(dian)平越(yue)高，輸(shu)(shu)出脈沖Va和(he)Vb的(de)(de)占空(kong)比(bi)越(yue)大(da)；反之(zhi)(zhi)越(yue)小。根據這一規(gui)律來實現該控制器(qi)的(de)(de)調(diao)壓、軟啟動及(ji)保(bao)護(hu)功能。另外，可以通過改變5腳(jiao)和(he)7腳(jiao)之(zhi)(zhi)間的(de)(de)外接電(dian)阻(zu)的(de)(de)大(da)小，使時鐘(zhong)脈沖寬度(du)變化來實現死區大(da)小的(de)(de)調(diao)節[2]。

　　4 充電器的控制與保護策略

　　航空蓄電(dian)(dian)池(chi)充電(dian)(dian)器(qi)的(de)控(kong)(kong)制原(yuan)理(li)框(kuang)圖如圖4所(suo)示。芯片SG3525產生(sheng)的(de)兩路(lu) PWM波(bo)經(jing)過光耦隔離以后，被送(song)入IR2130從而(er)驅動開(kai)關管(guan)工作(zuo)，由于(yu)充電(dian)(dian)器(qi)的(de)負載為(wei)電(dian)(dian)壓(ya)時(shi)刻變(bian)化的(de)航空蓄電(dian)(dian)池(chi)，因此在控(kong)(kong)制電(dian)(dian)路(lu)中還采用了(le)電(dian)(dian)壓(ya)電(dian)(dian)流雙閉環控(kong)(kong)制、過流及(ji)過溫(wen)保護電(dian)(dian)路(lu)，從而(er)能保證(zheng)充電(dian)(dian)器(qi)高效、可靠的(de)完成整個充電(dian)(dian)過程。     

   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(dao)蓄(xu)電(dian)(dian)池兩端電(dian)(dian)壓不再發(fa)生(sheng)明顯變化時(shi)，充(chong)電(dian)(dian)過程(cheng)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)電(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)充電(dian)(dian)(dian)(dian)(dian)器(qi)對(dui)某型號航空蓄(xu)電(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)進(jin)行了充電(dian)(dian)(dian)(dian)(dian)試(shi)驗(yan)，最大充電(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)流(liu)(liu)限制為(wei)(wei)30A，溫度限制值定為(wei)(wei)350C。蓄(xu)電(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)的(de)初始電(dian)(dian)(dian)(dian)(dian)壓為(wei)(wei)20V，充電(dian)(dian)(dian)(dian)(dian)開始時(shi)(shi)(shi)，充電(dian)(dian)(dian)(dian)(dian)器(qi)以(yi)20A的(de)電(dian)(dian)(dian)(dian)(dian)流(liu)(liu)對(dui)蓄(xu)電(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)持續充電(dian)(dian)(dian)(dian)(dian)約58分鐘(zhong)，然后(hou)以(yi)較小的(de)電(dian)(dian)(dian)(dian)(dian)流(liu)(liu)3A對(dui)蓄(xu)電(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)進(jin)行涓流(liu)(liu)充電(dian)(dian)(dian)(dian)(dian)，直至蓄(xu)電(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)電(dian)(dian)(dian)(dian)(dian)壓上(shang)(shang)升(sheng)到32.45V時(shi)(shi)(shi)，蓄(xu)電(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)兩(liang)端的(de)電(dian)(dian)(dian)(dian)(dian)壓不再(zai)發(fa)生明(ming)顯的(de)上(shang)(shang)升(sheng)現象，此時(shi)(shi)(shi)充電(dian)(dian)(dian)(dian)(dian)器(qi)停止充電(dian)(dian)(dian)(dian)(dian)，歷時(shi)(shi)(shi)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(shi)現了(le)恒流充(chong)電(dian)和(he)涓流充(chong)電(dian)功能(neng)，該充(chong)電(dian)器(qi)實(shi)現了(le)輸出與電(dian)網的高頻電(dian)氣(qi)隔(ge)離，充(chong)電(dian)效率高，使用(yong)方便(bian)(bian)，工作(zuo)穩(wen)定(ding)，有效地(di)縮短了(le)充(chong)電(dian)時間，提(ti)高了(le)充(chong)電(dian)質量，便(bian)(bian)于現場(chang)應用(yong)，滿足(zu)航空蓄電(dian)池的使用(yong)要求，現已經裝備使用(yong)，效果良好。