該航空蓄電池充電器為飛機某型號蓄電(dian)(dian)(dian)(dian)池專門設計，主要實現兩階段充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)功(gong)能，即恒流(liu)充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)狀態（以20A的大電(dian)(dian)(dian)(dian)流(liu)充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)）和涓(juan)流(liu)充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)狀態（以3A的小電(dian)(dian)(dian)(dian)流(liu)充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)）。蓄電(dian)(dian)(dian)(dian)池充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)器使用的工作電(dian)(dian)(dian)(dian)源(yuan)為115V/400Hz的航空電(dian)(dian)(dian)(dian)源(yuan)，充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)器能在1小時內完成恒流(liu)充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)，隨(sui)后以涓(juan)流(liu)狀態對蓄電(dian)(dian)(dian)(dian)池組進行(xing)充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)直至充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)結束，每個(ge)充(chong)(chong)(chong)電(dian)(dian)(dian)(dian)過程(cheng)在2個(ge)小時內完成。

　　2　充電器總體設計方案
 
 　　航空蓄(xu)電(dian)(dian)池充電(dian)(dian)器(qi)(qi)的主(zhu)電(dian)(dian)路(lu)如圖1所(suo)示，電(dian)(dian)源變(bian)(bian)換器(qi)(qi)采用了由半(ban)橋變(bian)(bian)換器(qi)(qi)、高(gao)頻變(bian)(bian)壓器(qi)(qi)和輸出整流濾波電(dian)(dian)路(lu)組成(cheng)的半(ban)橋變(bian)(bian)換器(qi)(qi)[1]，該電(dian)(dian)路(lu)結構簡單，工作(zuo)可靠，功率(lv)(lv)管(guan)為場(chang)效(xiao)應(ying)管(guan)，而且開關管(guan)承受的電(dian)(dian)壓為電(dian)(dian)源電(dian)(dian)壓，故可在電(dian)(dian)源電(dian)(dian)壓較高(gao)的場(chang)合應(ying)用。通(tong)常高(gao)頻大(da)功率(lv)(lv)變(bian)(bian)換器(qi)(qi)開關頻率(lv)(lv)一般都(dou)大(da)于15kHz，為了使功率(lv)(lv)電(dian)(dian)路(lu)小型化(hua)、減小失真(zhen)并保(bao)持高(gao)的變(bian)(bian)換效(xiao)率(lv)(lv)，該充電(dian)(dian)器(qi)(qi)采用了20kHz的開關頻率(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3 SG3525芯片各(ge)點的工(gong)作波形

 　　SG3525芯(xin)片(pian)各點的(de)(de)(de)工作波形(xing)如圖3所示，由誤(wu)差放大(da)(da)器(qi)(qi)輸(shu)出(chu)的(de)(de)(de)電(dian)(dian)壓Ve與鋸齒波的(de)(de)(de)交點可(ke)得一(yi)負的(de)(de)(de)PWM信(xin)號(hao)(hao)。由PWM信(xin)號(hao)(hao)、時(shi)鐘信(xin)號(hao)(hao)及(ji)分相器(qi)(qi)輸(shu)出(chu)的(de)(de)(de)Q (或 )信(xin)號(hao)(hao)，根(gen)據或非門的(de)(de)(de)邏輯可(ke)得兩個或非門的(de)(de)(de)輸(shu)出(chu)信(xin)號(hao)(hao)Va和(he)(he)Vb。由波形(xing)圖可(ke)以看(kan)出(chu)，PWM比較器(qi)(qi)的(de)(de)(de)反(fan)相輸(shu)入端電(dian)(dian)平越(yue)高，輸(shu)出(chu)脈沖Va和(he)(he)Vb的(de)(de)(de)占(zhan)空比越(yue)大(da)(da)；反(fan)之越(yue)小(xiao)。根(gen)據這一(yi)規律來(lai)實(shi)現該(gai)控制器(qi)(qi)的(de)(de)(de)調壓、軟啟動及(ji)保(bao)護功能。另外，可(ke)以通過(guo)改變5腳(jiao)和(he)(he)7腳(jiao)之間的(de)(de)(de)外接電(dian)(dian)阻的(de)(de)(de)大(da)(da)小(xiao)，使(shi)時(shi)鐘脈沖寬度變化(hua)來(lai)實(shi)現死區(qu)大(da)(da)小(xiao)的(de)(de)(de)調節[2]。

　　4 充電器的控制與保護策略

　　航空蓄電(dian)(dian)池(chi)充(chong)電(dian)(dian)器(qi)的(de)控制(zhi)原理(li)框(kuang)圖(tu)如圖(tu)4所示。芯片SG3525產(chan)生(sheng)的(de)兩路(lu) PWM波經過(guo)光耦隔(ge)離以后，被送入IR2130從(cong)而(er)(er)驅動開(kai)關管工作(zuo)，由于充(chong)電(dian)(dian)器(qi)的(de)負載(zai)為電(dian)(dian)壓(ya)時(shi)刻(ke)變化的(de)航空蓄電(dian)(dian)池(chi)，因此在控制(zhi)電(dian)(dian)路(lu)中還(huan)采用了電(dian)(dian)壓(ya)電(dian)(dian)流(liu)雙(shuang)閉環控制(zhi)、過(guo)流(liu)及過(guo)溫保護電(dian)(dian)路(lu)，從(cong)而(er)(er)能保證(zheng)充(chong)電(dian)(dian)器(qi)高效、可靠的(de)完(wan)成整(zheng)個充(chong)電(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(dao)蓄電(dian)池兩端電(dian)壓不再發生明顯(xian)變化時，充電(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。
  使用該蓄(xu)(xu)(xu)(xu)電(dian)(dian)(dian)池充(chong)電(dian)(dian)(dian)器對(dui)(dui)某型號航空蓄(xu)(xu)(xu)(xu)電(dian)(dian)(dian)池進行了充(chong)電(dian)(dian)(dian)試驗(yan)，最大充(chong)電(dian)(dian)(dian)電(dian)(dian)(dian)流(liu)限制為30A，溫(wen)度限制值(zhi)定為350C。蓄(xu)(xu)(xu)(xu)電(dian)(dian)(dian)池的(de)初(chu)始電(dian)(dian)(dian)壓(ya)為20V，充(chong)電(dian)(dian)(dian)開始時，充(chong)電(dian)(dian)(dian)器以20A的(de)電(dian)(dian)(dian)流(liu)對(dui)(dui)蓄(xu)(xu)(xu)(xu)電(dian)(dian)(dian)池持(chi)續(xu)充(chong)電(dian)(dian)(dian)約58分鐘，然后以較小的(de)電(dian)(dian)(dian)流(liu)3A對(dui)(dui)蓄(xu)(xu)(xu)(xu)電(dian)(dian)(dian)池進行涓流(liu)充(chong)電(dian)(dian)(dian)，直至蓄(xu)(xu)(xu)(xu)電(dian)(dian)(dian)池電(dian)(dian)(dian)壓(ya)上升到(dao)32.45V時，蓄(xu)(xu)(xu)(xu)電(dian)(dian)(dian)池兩(liang)端的(de)電(dian)(dian)(dian)壓(ya)不再發(fa)生明顯的(de)上升現象(xiang)，此時充(chong)電(dian)(dian)(dian)器停止充(chong)電(dian)(dian)(dian)，歷時150分鐘。

　　本文提出了一種鎘鎳航空蓄電池充電器的設(she)計方(fang)(fang)案和(he)控(kong)制原理，精確實(shi)(shi)現了(le)(le)恒流(liu)充(chong)(chong)電(dian)和(he)涓流(liu)充(chong)(chong)電(dian)功能，該充(chong)(chong)電(dian)器(qi)實(shi)(shi)現了(le)(le)輸出與電(dian)網的高頻電(dian)氣隔離，充(chong)(chong)電(dian)效率高，使(shi)用(yong)(yong)方(fang)(fang)便，工(gong)作穩定(ding)，有效地縮(suo)短了(le)(le)充(chong)(chong)電(dian)時間，提高了(le)(le)充(chong)(chong)電(dian)質量，便于(yu)現場應用(yong)(yong)，滿足航空蓄(xu)電(dian)池的使(shi)用(yong)(yong)要求(qiu)，現已經(jing)裝備使(shi)用(yong)(yong)，效果良好。