ANAPF有源電力濾波器

1、ANAPF產品介紹

ANAPF 模塊(kuai)工作原(yuan)理

      ANAPF 系(xi)列有(you)(you)源(yuan)電(dian)(dian)(dian)(dian)力(li)濾波(bo)(bo)器(qi)并聯在含(han)諧(xie)波(bo)(bo)負(fu)載的(de)低壓配電(dian)(dian)(dian)(dian)系(xi)統中，能夠對(dui)動態變(bian)化(hua)的(de)諧(xie)波(bo)(bo)電(dian)(dian)(dian)(dian)流(liu)(liu)進行快速實 時的(de)跟(gen)蹤和補償。其原(yuan)理為：ANAPF 系(xi)列有(you)(you)源(yuan)電(dian)(dian)(dian)(dian)力(li)濾波(bo)(bo)器(qi)通過(guo) CT 采(cai)集(ji)系(xi)統諧(xie)波(bo)(bo)電(dian)(dian)(dian)(dian)流(liu)(liu)，經控(kong)制器(qi)快速計算并提取(qu) 各次諧(xie)波(bo)(bo)電(dian)(dian)(dian)(dian)流(liu)(liu)的(de)含(han)量，產(chan)(chan)生諧(xie)波(bo)(bo)電(dian)(dian)(dian)(dian)流(liu)(liu)指令，通過(guo)功(gong)率執行器(qi)件產(chan)(chan)生與諧(xie)波(bo)(bo)電(dian)(dian)(dian)(dian)流(liu)(liu)幅值(zhi)相等方向相反的(de)補償電(dian)(dian)(dian)(dian)流(liu)(liu)，并 注入電(dian)(dian)(dian)(dian)力(li)系(xi)統中，從而抵(di)消非線性負(fu)載所產(chan)(chan)生的(de)諧(xie)波(bo)(bo)電(dian)(dian)(dian)(dian)流(liu)(liu)。

ANAPF 整機(ji)工作原理

      有(you)源電(dian)力濾波器是(shi)一(yi)種用于諧(xie)波治理、補(bu)(bu)償無功以及不平衡調(diao)節的(de)(de)新型電(dian)力電(dian)子(zi)裝(zhuang)置；智能控制(zhi)系統主動(dong)(dong)根據系 統的(de)(de)線性動(dong)(dong)態需求，自動(dong)(dong)調(diao)節模(mo)塊(kuai)的(de)(de)輸出；ANAPF整機(ji)(ji)主要是(shi)由ANAPF模(mo)塊(kuai)組成(cheng)(cheng)；能完成(cheng)(cheng)更大容量的(de)(de)諧(xie)波電(dian)流的(de)(de)補(bu)(bu) 償，整機(ji)(ji)通過一(yi)個7寸觸摸(mo)屏(ping)實現人(ren)機(ji)(ji)交互。觸摸(mo)屏(ping)通過RS485與(yu)ANAPF模(mo)塊(kuai)進行通信。

產品(pin)特點 

      1) 補償方(fang)式靈活(huo)：既可(ke)補諧波，又可(ke)兼(jian)補無(wu)功(gong)，可(ke)對 2-51 次諧波進(jin)行(xing)全(quan)補償或(huo)特定次諧波進(jin)行(xing)補償； 

      2) 可(ke)治理三相不平衡； 

      3) 線(xian)性補償(chang)，響應時間≤5ms； 

      4) 具(ju)有人性化(hua)的人機交互界(jie)面，可通過該界(jie)面看到系(xi)統(tong)和本體的實時電能質(zhi)量信(xin)息，操作簡單，可以遠(yuan)控，也 可以本控； 

      5) 采(cai)用進口 IGBT，功率密度大，可(ke)靠性高(gao)； 

      6) 采(cai)用 DSP 高(gao)速檢測(ce)和運算的(de)數字(zi)控制系統； 

      7) 監(jian)控以及顯示具(ju)備遠程通(tong)訊接(jie)口，可以通(tong)過 PC 機實時(shi)監(jian)控； 

      8) 標(biao)準模塊化設計(ji)，縮(suo)短交付周期，同時提(ti)高(gao)了使用的可靠性(xing)和可維護性(xing)。

2、外觀尺寸

3、技術參數

4、接線示意

5、諧波電流的估算

絕緣柵場效應晶體管(IGBT)作為一種復合型器件,集成了mosFET的電壓驅動和高開關頻率及功率管低損耗、大功率的特點,在電機控制、開關電源、變流裝置及許多要求快速、低損耗的領域中有著廣泛的應用。本文對應用于有源電力濾波器的(de)IGBT的(de)特性及其專有EXB84l型驅(qu)(qu)動器的(de)設計進(jin)行討論,并提出一(yi)種具(ju)有完善保護(hu)功能的(de)驅(qu)(qu)動電路。

　　有源電力濾波器設計中應用(yong)(yong)4個(ge)IGBT作(zuo)為開關(guan),并用(yong)(yong)4個(ge)EXB84l組成驅動(dong)電路,其原(yuan)理(li)如圖l所示。在實驗(yan)中,根據補償(chang)電流(liu)與指令電流(liu)的關(guan)系,用(yong)(yong)數字信(xin)號(hao)處(chu)理(li)器(DSP)控制PWM引腳的高低(di)電平,并由(you)驅動(dong)電路控制IGBT的通斷。驅動(dong)電路同(tong)時對過流(liu)故(gu)障進(jin)行監測,由(you)DSP采取控制信(xin)號(hao)、停(ting)機等處(chu)理(li)。

圖1 有源電力濾波器的IGBT驅動電(dian)路(lu)原理

1 驅動電路的設計(ji)

1.1 驅動電(dian)路(lu)電(dian)源

　　驅(qu)動電路(lu)(lu)需要4路(lu)(lu)相互隔離的直流(liu)電源(yuan)為4路(lu)(lu)IGBT驅(qu)動電路(lu)(lu)供電,用220V/22V變壓器(qi)對4路(lu)(lu)交(jiao)流(liu)電源(yuan)分(fen)別整流(liu),用電容(rong)器(qi)和78L24型電壓調整器(qi)穩壓后輸出4路(lu)(lu)24V直流(liu)電壓,如圖2所示。

圖2 IGBT驅(qu)動電路的電源設計

1.2 柵極電壓

　　IGBT通常采(cai)用(yong)柵(zha)(zha)極(ji)(ji)電(dian)壓(ya)(ya)(ya)驅(qu)(qu)動,它對柵(zha)(zha)極(ji)(ji)驅(qu)(qu)動電(dian)路有著特殊(shu)的(de)要(yao)求。柵(zha)(zha)極(ji)(ji)驅(qu)(qu)動電(dian)壓(ya)(ya)(ya)脈沖的(de)上升率和(he)下降率要(yao)足(zu)(zu)夠大,導(dao)(dao)(dao)通時(shi)(shi),前沿很(hen)陡的(de)柵(zha)(zha)極(ji)(ji)電(dian)壓(ya)(ya)(ya)UGE可(ke)(ke)以(yi)使IGBT快速導(dao)(dao)(dao)通,并(bing)減小導(dao)(dao)(dao)通損耗,關(guan)斷(duan)時(shi)(shi),其柵(zha)(zha)極(ji)(ji)驅(qu)(qu)動電(dian)路要(yao)給IGBT提(ti)供(gong)一個下降很(hen)陡的(de)關(guan)斷(duan)電(dian)壓(ya)(ya)(ya),并(bing)在(zai)(zai)柵(zha)(zha)極(ji)(ji)和(he)發射極(ji)(ji)之(zhi)間(jian)施(shi)加(jia)一個適當的(de)反(fan)向負偏(pian)壓(ya)(ya)(ya),以(yi)便使IGBT快速關(guan)斷(duan),并(bing)減小關(guan)斷(duan)損耗。IGBT導(dao)(dao)(dao)通后,柵(zha)(zha)極(ji)(ji)的(de)驅(qu)(qu)動電(dian)壓(ya)(ya)(ya)和(he)電(dian)流要(yao)有足(zu)(zu)夠的(de)寬(kuan)度,以(yi)保證IGBT在(zai)(zai)瞬時(shi)(shi)過載(zai)時(shi)(shi)未退出飽(bao)和(he)區(qu)受到損壞(huai)。柵(zha)(zha)極(ji)(ji)驅(qu)(qu)動電(dian)壓(ya)(ya)(ya)值為15 V±1.5 V,這個電(dian)壓(ya)(ya)(ya)值使IGBT*飽(bao)和(he)導(dao)(dao)(dao)通,并(bing)使通態損耗減至(zhi)小。施(shi)加(jia)關(guan)斷(duan)負偏(pian)壓(ya)(ya)(ya)可(ke)(ke)以(yi)抑(yi)制C-E間(jian)出現(xian)du/dt時(shi)(shi)IGBT的(de)誤導(dao)(dao)(dao)通,也可(ke)(ke)以(yi)減少關(guan)斷(duan)損耗。

1.3 門(men)極電阻R1

　　門(men)極(ji)電(dian)阻(zu)R1的(de)(de)選取對通態電(dian)壓、開(kai)(kai)關(guan)(guan)時(shi)間、開(kai)(kai)關(guan)(guan)損(sun)(sun)耗(hao)及承受短(duan)路的(de)(de)能力都有(you)不同程(cheng)度(du)的(de)(de)影響。當門(men)極(ji)電(dian)阻(zu)增(zeng)(zeng)大時(shi),IGBT的(de)(de)開(kai)(kai)通和關(guan)(guan)斷(duan)時(shi)間增(zeng)(zeng)加,從而使導通和關(guan)(guan)斷(duan)損(sun)(sun)耗(hao)增(zeng)(zeng)加。當門(men)極(ji)電(dian)阻(zu)減小時(shi),則會導致(zhi)di/dt增(zeng)(zeng)加,從而引起IGBT的(de)(de)誤導通。所以應根據IGBT的(de)(de)電(dian)流容量和電(dian)壓額定值以及開(kai)(kai)關(guan)(guan)頻率的(de)(de)不同選擇R1的(de)(de)阻(zu)值。

　　Rl的值可以用(yong)下式計(ji)算：

　　IC為IGBT的(de)(de)集電極(ji)電流(liu)。如圖3所(suo)示(shi),一(yi)般R1取(qu)十幾(ji)歐姆到(dao)幾(ji)十歐姆,R2為30 Ω。由于IGBT是壓控器(qi)件(jian),當集-射(she)(she)極(ji)間加高壓時,很容易受外(wai)界干擾,而使柵-射(she)(she)極(ji)間電壓超過(guo)一(yi)定值,引起(qi)器(qi)件(jian)誤導通,為了防止這種現(xian)象的(de)(de)發(fa)生,在(zai)柵-射(she)(she)極(ji)間并(bing)聯一(yi)電阻(zu)器(qi)R6可起(qi)到(dao)一(yi)定作用(yong)。一(yi)般R6阻(zu)值是R2阻(zu)值的(de)(de)l 000~5 000倍,而且應(ying)將(jiang)它并(bing)聯在(zai)柵-射(she)(she)極(ji)近(jin)處(chu)。電路中(zhong)的(de)(de)電容器(qi)Cl和C2用(yong)來抑制(zhi)因電源(yuan)接(jie)線(xian)阻(zu)抗引起(qi)的(de)(de)供電電壓變化(hua),而不是用(yong)于電源(yuan)濾(lv)波。

1.4 EXB841驅(qu)動環節

　　筆者(zhe)在實(shi)驗(yan)中采用的(de)是EXB841型IGBT驅動(dong)模(mo)塊,其高運(yun)行(xing)(xing)頻率為(wei)40 kHz,輸入(ru)信(xin)號經內部(bu)光耦隔離(li),光隔驅動(dong)電(dian)(dian)流為(wei)10 mA,大延時約(yue)為(wei)1 μs。工作溫度(du)范(fan)圍(wei)為(wei)-10℃~+85℃,供(gong)電(dian)(dian)電(dian)(dian)壓為(wei)+20 V～+25 V。筆者(zhe)對(dui)EXB841功能(neng)進行(xing)(xing)了(le)擴展,圖3為(wei)驅動(dong)環節電(dian)(dian)路。

圖3 有源電力濾波器的IGBT驅動電(dian)路(lu)圖(tu)

　　EXB841的(de)(de)6引(yin)腳(jiao)連接的(de)(de)二極(ji)管可檢測IGBT的(de)(de)飽和壓降,用來完成過(guo)(guo)(guo)流保(bao)護(hu)功(gong)能,4引(yin)腳(jiao)的(de)(de)過(guo)(guo)(guo)流保(bao)護(hu)信(xin)(xin)號延(yan)時(shi)(shi)10μs輸(shu)出。當IGBT有(you)過(guo)(guo)(guo)流時(shi)(shi),若UCE大(da)于7.5V,內部過(guo)(guo)(guo)流保(bao)護(hu)電(dian)(dian)路開始動作(zuo),軟(ruan)關斷IG-BT。通(tong)常在IGBT通(tong)過(guo)(guo)(guo)額定電(dian)(dian)流時(shi)(shi)UCE為3.5 V,當UCE=7.5 V時(shi)(shi),IGBT有(you)過(guo)(guo)(guo)流,其值(zhi)約為額定電(dian)(dian)流的(de)(de)3~5倍(bei),但是由于沒(mei)有(you)達(da)到保(bao)護(hu)的(de)(de)閾(yu)值(zhi),保(bao)護(hu)電(dian)(dian)路不(bu)起作(zuo)用。如(ru)果長(chang)時(shi)(shi)間工(gong)作(zuo)在這種狀態,則會導致IGBT損壞(huai)。為了可靠地保(bao)護(hu)IGBT,應該降低(di)(di)過(guo)(guo)(guo)流保(bao)護(hu)閾(yu)值(zhi),可以在D1與(yu)IGBT的(de)(de)集電(dian)(dian)極(ji)間反串(chuan)一(yi)個(ge)穩壓管,或多串(chuan)幾(ji)個(ge)與(yu)D1同(tong)規格的(de)(de)快速恢復二極(ji)管。如(ru)圖3通(tong)過(guo)(guo)(guo)反串(chuan)一(yi)個(ge)IN4728型(xing)3.3 V穩壓管使保(bao)護(hu)閾(yu)值(zhi)降為4.2V。當檢測到IGBT過(guo)(guo)(guo)流后,5引(yin)腳(jiao)變為低(di)(di)電(dian)(dian)平(ping),TPL521型(xing)光耦輸(shu)出低(di)(di)電(dian)(dian)平(ping),通(tong)過(guo)(guo)(guo)與(yu)門控制信(xin)(xin)號輸(shu)入,同(tong)時(shi)(shi)使4輸(shu)入與(yu)非門輸(shu)出低(di)(di)電(dian)(dian)平(ping),觸發功(gong)率驅動保(bao)護(hu)中斷,完成相應的(de)(de)保(bao)護(hu)處理。

1.5 控制部分與驅動(dong)部分的(de)隔(ge)離

　　控(kong)(kong)制電(dian)(dian)路為(wei)(wei)弱電(dian)(dian)部分(fen),極(ji)易受到(dao)干擾(rao);驅(qu)動電(dian)(dian)路直接與外電(dian)(dian)路連接,是一(yi)個較強的干擾(rao)源;為(wei)(wei)了實現(xian)整個設備的電(dian)(dian)磁兼容(rong),控(kong)(kong)制電(dian)(dian)路部分(fen)必須與驅(qu)動部分(fen)隔(ge)離。為(wei)(wei)了避免公共電(dian)(dian)源對控(kong)(kong)制電(dian)(dian)路產生干擾(rao),應對控(kong)(kong)制電(dian)(dian)路及驅(qu)動電(dian)(dian)路分(fen)別供電(dian)(dian),EXB84l的電(dian)(dian)源電(dian)(dian)壓為(wei)(wei)+20 V,一(yi)般控(kong)(kong)制電(dian)(dian)路的供電(dian)(dian)電(dian)(dian)壓為(wei)(wei)5 V,因此,可以利用圖4所示的DC-DC微(wei)功率模塊(kuai)進行電(dian)(dian)源隔(ge)離,采用A2405D型微(wei)功率模塊(kuai)實現(xian)電(dian)(dian)源的隔(ge)離。

2 IGBT及驅動電路的保護(hu)

2.1 IGBT的過電壓保護

　　IGBT集-射極(ji)之(zhi)間的(de)瞬時過壓(ya)會對IGBT造成損壞,筆者采用(yong)箝位式吸(xi)收(shou)(shou)電(dian)(dian)(dian)(dian)(dian)(dian)路對瞬時過電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)進行抑制(zhi)。當IGBT導通時,由于(yu)二極(ji)管(guan)的(de)作用(yong),電(dian)(dian)(dian)(dian)(dian)(dian)容(rong)器的(de)電(dian)(dian)(dian)(dian)(dian)(dian)荷不會被(bei)放掉(diao),電(dian)(dian)(dian)(dian)(dian)(dian)容(rong)器電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)仍為電(dian)(dian)(dian)(dian)(dian)(dian)源電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)。IGBT關斷時,負載電(dian)(dian)(dian)(dian)(dian)(dian)流(liu)仍流(liu)過IGBT,直到IGBT集-射極(ji)之(zhi)間電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)達到電(dian)(dian)(dian)(dian)(dian)(dian)源電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya),續流(liu)二極(ji)管(guan)導通。應用(yong)該電(dian)(dian)(dian)(dian)(dian)(dian)路,可(ke)(ke)以(yi)使雜散電(dian)(dian)(dian)(dian)(dian)(dian)感中的(de)能量通過二極(ji)管(guan)轉儲到吸(xi)收(shou)(shou)電(dian)(dian)(dian)(dian)(dian)(dian)容(rong)器中,而IGBT的(de)集電(dian)(dian)(dian)(dian)(dian)(dian)極(ji)電(dian)(dian)(dian)(dian)(dian)(dian)位被(bei)箝位在電(dian)(dian)(dian)(dian)(dian)(dian)容(rong)電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)上,這(zhe)樣就可(ke)(ke)以(yi)抑制(zhi)IGBT集電(dian)(dian)(dian)(dian)(dian)(dian)極(ji)的(de)尖峰(feng)電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)。吸(xi)收(shou)(shou)電(dian)(dian)(dian)(dian)(dian)(dian)容(rong)器的(de)容(rong)值可(ke)(ke)以(yi)按公式(2)選取：

　　式中(zhong),L是(shi)引線電(dian)(dian)感(gan);i是(shi)IGBT關斷(duan)時的電(dian)(dian)流;△U是(shi)吸收電(dian)(dian)容器上(shang)的電(dian)(dian)壓過沖。

　　當(dang)吸(xi)(xi)(xi)收(shou)(shou)回路中的電(dian)(dian)(dian)容(rong)(rong)器(qi)(qi)電(dian)(dian)(dian)壓(ya)(ya)高(gao)(gao)于(yu)(yu)直(zhi)流側(ce)電(dian)(dian)(dian)容(rong)(rong)器(qi)(qi)上(shang)(shang)的電(dian)(dian)(dian)壓(ya)(ya)時(shi)(shi),通過(guo)電(dian)(dian)(dian)阻(zu)器(qi)(qi)向直(zhi)流側(ce)電(dian)(dian)(dian)容(rong)(rong)器(qi)(qi)回送(song)能量(liang),一直(zhi)到與直(zhi)流側(ce)電(dian)(dian)(dian)容(rong)(rong)器(qi)(qi)的電(dian)(dian)(dian)壓(ya)(ya)相(xiang)(xiang)等。當(dang)IGBT關斷(duan)時(shi)(shi),線(xian)路電(dian)(dian)(dian)感(gan)在集電(dian)(dian)(dian)極(ji)和發(fa)射極(ji)二端產生很高(gao)(gao)的尖峰(feng)(feng)電(dian)(dian)(dian)壓(ya)(ya),加上(shang)(shang)箝位式吸(xi)(xi)(xi)收(shou)(shou)電(dian)(dian)(dian)路以(yi)后,UCE被箝位在電(dian)(dian)(dian)容(rong)(rong)器(qi)(qi)電(dian)(dian)(dian)壓(ya)(ya)上(shang)(shang),當(dang)UCE高(gao)(gao)于(yu)(yu)電(dian)(dian)(dian)容(rong)(rong)器(qi)(qi)電(dian)(dian)(dian)壓(ya)(ya)時(shi)(shi),線(xian)路電(dian)(dian)(dian)感(gan)的能量(liang)被轉移到吸(xi)(xi)(xi)收(shou)(shou)電(dian)(dian)(dian)容(rong)(rong)器(qi)(qi)上(shang)(shang),當(dang)尖峰(feng)(feng)電(dian)(dian)(dian)壓(ya)(ya)過(guo)去以(yi)后,吸(xi)(xi)(xi)收(shou)(shou)電(dian)(dian)(dian)容(rong)(rong)高(gao)(gao)于(yu)(yu)主電(dian)(dian)(dian)容(rong)(rong)的那部分(fen)電(dian)(dian)(dian)壓(ya)(ya)會(hui)由于(yu)(yu)能量(liang)回進而達(da)到與主電(dian)(dian)(dian)容(rong)(rong)相(xiang)(xiang)等。這(zhe)樣(yang)就(jiu)抑制了(le)(le)集-射極(ji)間的尖峰(feng)(feng)電(dian)(dian)(dian)壓(ya)(ya)。吸(xi)(xi)(xi)收(shou)(shou)電(dian)(dian)(dian)容(rong)(rong)越大(da),吸(xi)(xi)(xi)收(shou)(shou)效(xiao)果越好。由于(yu)(yu)吸(xi)(xi)(xi)收(shou)(shou)電(dian)(dian)(dian)容(rong)(rong)器(qi)(qi)上(shang)(shang)過(guo)沖的能量(liang)大(da)部分(fen)被送(song)回到直(zhi)流側(ce)電(dian)(dian)(dian)容(rong)(rong),所(suo)以(yi)減小了(le)(le)電(dian)(dian)(dian)阻(zu)器(qi)(qi)的功耗。

2.2 消除IGBT集-柵極之間的du/dt

　　圖(tu)5所示(shi)為EXB841與IGBT柵(zha)-射極之(zhi)間(jian)的(de)(de)連(lian)接(jie)電(dian)(dian)路原理圖(tu)。當(dang)驅動(dong)電(dian)(dian)路中(zhong)的(de)(de)V4導(dao)通時,IGBT處于(yu)正(zheng)常導(dao)通狀(zhuang)態,當(dang)V5導(dao)通時,IGBT柵(zha)-射極之(zhi)間(jian)通過(guo)穩(wen)壓(ya)管(guan)(guan)VZ2提供一個-5V電(dian)(dian)壓(ya)加在(zai)其兩端,使IGBT關斷,此時V5處于(yu)臨界導(dao)通狀(zhuang)態,穩(wen)壓(ya)管(guan)(guan)VZ2處于(yu)反向偏置(zhi)狀(zhuang)態。但由于(yu)集(ji)-柵(zha)極之(zhi)間(jian)分(fen)布(bu)電(dian)(dian)容的(de)(de)影響,集(ji)-柵(zha)極之(zhi)間(jian)的(de)(de)du/dt增大時,其通過(guo)分(fen)布(bu)電(dian)(dian)容形(xing)成的(de)(de)電(dian)(dian)流經過(guo),所以,要(yao)克服集(ji)-柵(zha)極之(zhi)間(jian)的(de)(de)du/dt,確保穩(wen)壓(ya)管(guan)(guan)不(bu)過(guo)壓(ya),避免IGBT誤導(dao)通。克服du/dt的(de)(de)方法(fa)有二(er)種：一是(shi)驅動(dong)電(dian)(dian)路輸出與IGBT柵(zha)-射極之(zhi)間(jian)的(de)(de)連(lian)線采(cai)用雙絞屏(ping)蔽電(dian)(dian)纜,屏(ping)蔽層(ceng)接(jie)地,二(er)是(shi)采(cai)用快速(su)吸收電(dian)(dian)路吸收過(guo)電(dian)(dian)壓(ya)。

2.3 EXB841的(de)過流保護功能擴展

　　EXB841自身具有過(guo)流(liu)保(bao)(bao)護(hu)功能,其保(bao)(bao)護(hu)原理是利用IGBT的(de)集(ji)電(dian)(dian)(dian)極(ji)通態(tai)(tai)飽和壓降與(yu)集(ji)電(dian)(dian)(dian)極(ji)電(dian)(dian)(dian)流(liu)呈近似線性關系。當IGBT工作(zuo)在正(zheng)常狀(zhuang)態(tai)(tai)時,EXB841的(de)6腳(jiao)電(dian)(dian)(dian)位箝制在8 V,內部保(bao)(bao)護(hu)不動作(zuo),當IGBT因(yin)承受過(guo)流(liu)而退(tui)出飽和狀(zhuang)態(tai)(tai)時,IGBT集(ji)-射極(ji)間的(de)電(dian)(dian)(dian)壓上(shang)升很多,與(yu)EXB84l的(de)6引腳(jiao)相連的(de)快速(su)二極(ji)管截止,EXB841的(de)6引腳(jiao)被懸空,內部保(bao)(bao)護(hu)動作(zuo),輸出驅動電(dian)(dian)(dian)壓慢慢下降,實現(xian)IGBT的(de)軟關斷。

　　在(zai)實際(ji)應用中(zhong),僅靠EXB841的(de)(de)6引(yin)腳檢(jian)測IG-BT集電(dian)(dian)極(ji)電(dian)(dian)壓(ya)來(lai)實現過(guo)流(liu)保護(hu)并不足以(yi)有(you)效(xiao)(xiao)地保護(hu)IGBT,因此有(you)必(bi)要在(zai)主電(dian)(dian)路(lu)(lu)(lu)中(zhong)加接(jie)霍(huo)(huo)爾電(dian)(dian)流(liu)傳感器(qi)來(lai)檢(jian)測電(dian)(dian)路(lu)(lu)(lu)中(zhong)的(de)(de)過(guo)流(liu),如(ru)(ru)圖(tu)6所(suo)示(shi)。過(guo)流(liu)發(fa)生后,檢(jian)測電(dian)(dian)路(lu)(lu)(lu)檢(jian)測到電(dian)(dian)流(liu),延時(shi)8μs后信(xin)號還存在(zai)的(de)(de)話。驅動信(xin)號以(yi)關斷IGBT。在(zai)圖(tu)中(zhong),霍(huo)(huo)爾電(dian)(dian)流(liu)傳感器(qi)如(ru)(ru)果(guo)在(zai)主電(dian)(dian)路(lu)(lu)(lu)中(zhong)檢(jian)測到過(guo)流(liu)信(xin)號,其中(zhong)的(de)(de)PNP三(san)極(ji)管(guan)將導通,同(tong)時(shi),NPN三(san)極(ji)管(guan)被(bei)截(jie)止,EXB841的(de)(de)6腳被(bei)懸空(kong);當沒有(you)過(guo)流(liu)信(xin)號時(shi),PNP三(san)極(ji)管(guan)不導通,NPN三(san)極(ji)管(guan)導通,此時(shi)電(dian)(dian)路(lu)(lu)(lu)等(deng)效(xiao)(xiao)于擴展(zhan)前(qian)的(de)(de)電(dian)(dian)路(lu)(lu)(lu)。

3 結束語

　　本設(she)計應用(yong)以上電路對(dui)IGBT進行(xing)驅動(dong)和保護(hu)。此驅動(dong)電路是(shi)在典型驅動(dong)電路的(de)(de)基(ji)礎上進行(xing)改進和完善的(de)(de),并且自行(xing)設(she)計了(le)隔離部分和過(guo)電流保護(hu)擴(kuo)展部分。此驅動(dong)電路相(xiang)對(dui)簡單、實用(yong),對(dui)被驅動(dong)的(de)(de)IGBT有(you)(you)完善的(de)(de)保護(hu)能(neng)力(li),輸(shu)出阻抗(kang)(kang)低(di),具有(you)(you)較強(qiang)的(de)(de)抗(kang)(kang)干擾性能(neng)。

　　應(ying)用這種(zhong)IGBT模塊的(de)有源濾波(bo)器的(de)樣機通(tong)過試(shi)驗,證明硬件能夠協調配合,控制效果穩定(ding)、精確(que),并且(qie)已經批量制板(ban)。