ANAPF有源電力濾波器

1、ANAPF產(chan)品介紹

ANAPF 模塊工作原理

ANAPF 系(xi)(xi)列(lie)(lie)有源電(dian)(dian)(dian)力(li)(li)濾波(bo)器并(bing)(bing)聯在含諧(xie)波(bo)負載的(de)(de)低壓配電(dian)(dian)(dian)系(xi)(xi)統(tong)中(zhong)，能夠(gou)對動態變化的(de)(de)諧(xie)波(bo)電(dian)(dian)(dian)流(liu)(liu)進行快(kuai)(kuai)速實 時的(de)(de)跟蹤和補(bu)償(chang)。其(qi)原(yuan)理(li)為(wei)：ANAPF 系(xi)(xi)列(lie)(lie)有源電(dian)(dian)(dian)力(li)(li)濾波(bo)器通過 CT 采集系(xi)(xi)統(tong)諧(xie)波(bo)電(dian)(dian)(dian)流(liu)(liu)，經控制(zhi)器快(kuai)(kuai)速計算并(bing)(bing)提(ti)取(qu) 各次諧(xie)波(bo)電(dian)(dian)(dian)流(liu)(liu)的(de)(de)含量，產(chan)生(sheng)(sheng)諧(xie)波(bo)電(dian)(dian)(dian)流(liu)(liu)指令，通過功(gong)率(lv)執行器件產(chan)生(sheng)(sheng)與諧(xie)波(bo)電(dian)(dian)(dian)流(liu)(liu)幅值相等方向相反(fan)的(de)(de)補(bu)償(chang)電(dian)(dian)(dian)流(liu)(liu)，并(bing)(bing) 注(zhu)入(ru)電(dian)(dian)(dian)力(li)(li)系(xi)(xi)統(tong)中(zhong)，從而(er)抵(di)消非(fei)線性負載所產(chan)生(sheng)(sheng)的(de)(de)諧(xie)波(bo)電(dian)(dian)(dian)流(liu)(liu)。

ANAPF 整機工(gong)作原理

     有源電(dian)力濾波(bo)(bo)器是一(yi)種用(yong)于諧波(bo)(bo)治理(li)、補償(chang)無功以及不平衡調(diao)節的新型電(dian)力電(dian)子裝置(zhi)；智能控(kong)制系統主動根據系 統的線性動態需求，自動調(diao)節模塊的輸出(chu)；ANAPF整機(ji)主要(yao)是由ANAPF模塊組成；能完成更(geng)大(da)容量的諧波(bo)(bo)電(dian)流的補 償(chang)，整機(ji)通過一(yi)個7寸觸(chu)摸屏實現(xian)人機(ji)交互。觸(chu)摸屏通過RS485與ANAPF模塊進行(xing)通信。

產品特點

     1) 補償方式靈(ling)活：既(ji)可(ke)(ke)補諧波(bo)，又可(ke)(ke)兼補無功，可(ke)(ke)對 2-51 次諧波(bo)進行(xing)全補償或(huo)特(te)定次諧波(bo)進行(xing)補償；

     2) 可治理三相不平衡；

     3) 線性補償，響(xiang)應時間≤5ms；

     4) 具有人性(xing)化的人機交(jiao)互界面(mian)，可通過該界面(mian)看到系統和本體的實時電能質量(liang)信(xin)息，操作(zuo)簡單，可以(yi)(yi)遠控，也 可以(yi)(yi)本控；

     5) 采用進口 IGBT，功率密度大，可(ke)靠性(xing)高；

     6) 采(cai)用 DSP 高速檢測和(he)運算的數(shu)字控制(zhi)系統；

     7) 監控以及顯示具備遠程通訊接口，可以通過 PC 機實(shi)時(shi)監控；

     8) 標(biao)準模塊化設計，縮短交付周期，同時提高了(le)使用的可靠性(xing)和(he)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IGBT的特性及(ji)其專(zhuan)有EXB84l型驅動器的設(she)計進行討論,并提出一(yi)種具有完(wan)善保(bao)護(hu)功能(neng)的驅動電路。

　　有源電力濾波器設計中應用4個IGBT作(zuo)為開關(guan),并(bing)用4個EXB84l組成(cheng)驅(qu)動電(dian)(dian)路,其原理如(ru)圖l所示(shi)。在(zai)實驗中,根(gen)據補(bu)償電(dian)(dian)流與指(zhi)令電(dian)(dian)流的關(guan)系,用數字信(xin)號處理器(DSP)控(kong)制(zhi)(zhi)PWM引(yin)腳(jiao)的高低電(dian)(dian)平(ping),并(bing)由(you)驅(qu)動電(dian)(dian)路控(kong)制(zhi)(zhi)IGBT的通(tong)斷。驅(qu)動電(dian)(dian)路同時對過流故障(zhang)進行監測,由(you)DSP采取控(kong)制(zhi)(zhi)信(xin)號、停機等處理。

圖1 有源電力濾波器的(de)IGBT驅(qu)動(dong)電路原理

1 驅動(dong)電路的設(she)計

1.1 驅動(dong)電路電源

　　驅動(dong)電(dian)(dian)(dian)路(lu)(lu)(lu)需(xu)要4路(lu)(lu)(lu)相互隔(ge)離的(de)直(zhi)流(liu)(liu)電(dian)(dian)(dian)源(yuan)為4路(lu)(lu)(lu)IGBT驅動(dong)電(dian)(dian)(dian)路(lu)(lu)(lu)供電(dian)(dian)(dian),用(yong)220V/22V變壓器對(dui)4路(lu)(lu)(lu)交流(liu)(liu)電(dian)(dian)(dian)源(yuan)分別整流(liu)(liu),用(yong)電(dian)(dian)(dian)容器和78L24型電(dian)(dian)(dian)壓調整器穩壓后(hou)輸出4路(lu)(lu)(lu)24V直(zhi)流(liu)(liu)電(dian)(dian)(dian)壓,如圖2所示。

圖2 IGBT驅動(dong)電路的電源設計

1.2 柵極電壓

　　IGBT通(tong)(tong)(tong)常采用柵(zha)(zha)(zha)極(ji)(ji)電(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)驅(qu)(qu)動(dong)(dong),它(ta)對(dui)柵(zha)(zha)(zha)極(ji)(ji)驅(qu)(qu)動(dong)(dong)電(dian)(dian)(dian)(dian)(dian)路(lu)有著特(te)殊的要(yao)求。柵(zha)(zha)(zha)極(ji)(ji)驅(qu)(qu)動(dong)(dong)電(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)脈沖的上升率和下(xia)降率要(yao)足(zu)夠大,導(dao)(dao)通(tong)(tong)(tong)時,前(qian)沿很陡(dou)的柵(zha)(zha)(zha)極(ji)(ji)電(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)UGE可以(yi)使(shi)IGBT快(kuai)速導(dao)(dao)通(tong)(tong)(tong),并減(jian)(jian)小(xiao)導(dao)(dao)通(tong)(tong)(tong)損(sun)(sun)耗(hao),關(guan)斷(duan)時,其柵(zha)(zha)(zha)極(ji)(ji)驅(qu)(qu)動(dong)(dong)電(dian)(dian)(dian)(dian)(dian)路(lu)要(yao)給IGBT提(ti)供一(yi)個下(xia)降很陡(dou)的關(guan)斷(duan)電(dian)(dian)(dian)(dian)(dian)壓(ya)(ya),并在(zai)(zai)柵(zha)(zha)(zha)極(ji)(ji)和發射極(ji)(ji)之間施(shi)加(jia)一(yi)個適當的反向負(fu)偏(pian)壓(ya)(ya),以(yi)便(bian)使(shi)IGBT快(kuai)速關(guan)斷(duan),并減(jian)(jian)小(xiao)關(guan)斷(duan)損(sun)(sun)耗(hao)。IGBT導(dao)(dao)通(tong)(tong)(tong)后(hou),柵(zha)(zha)(zha)極(ji)(ji)的驅(qu)(qu)動(dong)(dong)電(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)和電(dian)(dian)(dian)(dian)(dian)流(liu)要(yao)有足(zu)夠的寬度(du),以(yi)保證IGBT在(zai)(zai)瞬時過載(zai)時未退出(chu)飽(bao)和區受到損(sun)(sun)壞(huai)。柵(zha)(zha)(zha)極(ji)(ji)驅(qu)(qu)動(dong)(dong)電(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)值為(wei)15 V±1.5 V,這個電(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)值使(shi)IGBT*飽(bao)和導(dao)(dao)通(tong)(tong)(tong),并使(shi)通(tong)(tong)(tong)態損(sun)(sun)耗(hao)減(jian)(jian)至(zhi)小(xiao)。施(shi)加(jia)關(guan)斷(duan)負(fu)偏(pian)壓(ya)(ya)可以(yi)抑制C-E間出(chu)現du/dt時IGBT的誤導(dao)(dao)通(tong)(tong)(tong),也可以(yi)減(jian)(jian)少(shao)關(guan)斷(duan)損(sun)(sun)耗(hao)。

1.3 門(men)極電阻(zu)R1

　　門(men)極(ji)電阻(zu)R1的(de)(de)(de)(de)選(xuan)取(qu)對通(tong)(tong)態電壓、開關(guan)(guan)時(shi)間、開關(guan)(guan)損(sun)耗(hao)及承受短(duan)路的(de)(de)(de)(de)能力都(dou)有不(bu)同(tong)程度(du)的(de)(de)(de)(de)影響(xiang)。當門(men)極(ji)電阻(zu)增(zeng)大(da)時(shi),IGBT的(de)(de)(de)(de)開通(tong)(tong)和關(guan)(guan)斷時(shi)間增(zeng)加(jia),從(cong)而使(shi)導通(tong)(tong)和關(guan)(guan)斷損(sun)耗(hao)增(zeng)加(jia)。當門(men)極(ji)電阻(zu)減小(xiao)時(shi),則會導致di/dt增(zeng)加(jia),從(cong)而引起IGBT的(de)(de)(de)(de)誤導通(tong)(tong)。所(suo)以(yi)應根據(ju)IGBT的(de)(de)(de)(de)電流容量和電壓額定值以(yi)及開關(guan)(guan)頻(pin)率的(de)(de)(de)(de)不(bu)同(tong)選(xuan)擇R1的(de)(de)(de)(de)阻(zu)值。

　　Rl的(de)值可(ke)以用下(xia)式計算：

　　IC為IGBT的集(ji)電(dian)(dian)極電(dian)(dian)流(liu)。如圖3所示,一(yi)(yi)般(ban)R1取(qu)十幾(ji)歐姆到幾(ji)十歐姆,R2為30 Ω。由于IGBT是壓(ya)控(kong)器(qi)件,當集(ji)-射極間加高壓(ya)時,很容易受外界干擾,而使(shi)柵(zha)-射極間電(dian)(dian)壓(ya)超過一(yi)(yi)定(ding)值,引起(qi)器(qi)件誤(wu)導通(tong),為了防止這種現(xian)象的發生,在柵(zha)-射極間并聯(lian)一(yi)(yi)電(dian)(dian)阻器(qi)R6可起(qi)到一(yi)(yi)定(ding)作(zuo)用。一(yi)(yi)般(ban)R6阻值是R2阻值的l 000~5 000倍,而且應將它并聯(lian)在柵(zha)-射極近(jin)處。電(dian)(dian)路中的電(dian)(dian)容器(qi)Cl和C2用來抑制因電(dian)(dian)源接線阻抗引起(qi)的供電(dian)(dian)電(dian)(dian)壓(ya)變化,而不(bu)是用于電(dian)(dian)源濾(lv)波。

1.4 EXB841驅動(dong)環節(jie)

　　筆者在實驗中采用的是EXB841型IGBT驅動(dong)模塊,其高運行頻(pin)率為(wei)40 kHz,輸入信號(hao)經內部(bu)光(guang)耦隔(ge)離,光(guang)隔(ge)驅動(dong)電流為(wei)10 mA,大延時約為(wei)1 μs。工作溫度范圍為(wei)-10℃~+85℃,供電電壓為(wei)+20 V～+25 V。筆者對EXB841功(gong)能(neng)進行了擴展,圖3為(wei)驅動(dong)環(huan)節電路(lu)。

圖3 有源電力濾波器的IGBT驅動電(dian)路圖

　　EXB841的(de)(de)6引腳連接的(de)(de)二(er)極(ji)管可(ke)檢(jian)測(ce)IGBT的(de)(de)飽和壓降,用來完成過(guo)(guo)流(liu)保(bao)(bao)護(hu)(hu)(hu)功能,4引腳的(de)(de)過(guo)(guo)流(liu)保(bao)(bao)護(hu)(hu)(hu)信號(hao)延時(shi)(shi)10μs輸(shu)出(chu)。當(dang)IGBT有過(guo)(guo)流(liu)時(shi)(shi),若UCE大(da)于7.5V,內部(bu)過(guo)(guo)流(liu)保(bao)(bao)護(hu)(hu)(hu)電(dian)(dian)路(lu)(lu)開始(shi)動(dong)(dong)作,軟關斷(duan)IG-BT。通(tong)常在(zai)(zai)IGBT通(tong)過(guo)(guo)額(e)定(ding)電(dian)(dian)流(liu)時(shi)(shi)UCE為3.5 V,當(dang)UCE=7.5 V時(shi)(shi),IGBT有過(guo)(guo)流(liu),其值約(yue)為額(e)定(ding)電(dian)(dian)流(liu)的(de)(de)3~5倍(bei),但是(shi)由于沒有達到(dao)保(bao)(bao)護(hu)(hu)(hu)的(de)(de)閾值,保(bao)(bao)護(hu)(hu)(hu)電(dian)(dian)路(lu)(lu)不起(qi)作用。如(ru)果長(chang)時(shi)(shi)間(jian)工作在(zai)(zai)這種狀態(tai),則會導致IGBT損壞。為了(le)可(ke)靠(kao)地保(bao)(bao)護(hu)(hu)(hu)IGBT,應該降低過(guo)(guo)流(liu)保(bao)(bao)護(hu)(hu)(hu)閾值,可(ke)以在(zai)(zai)D1與IGBT的(de)(de)集電(dian)(dian)極(ji)間(jian)反串一個(ge)(ge)穩(wen)(wen)壓管,或多串幾個(ge)(ge)與D1同規格(ge)的(de)(de)快速恢(hui)復二(er)極(ji)管。如(ru)圖3通(tong)過(guo)(guo)反串一個(ge)(ge)IN4728型3.3 V穩(wen)(wen)壓管使保(bao)(bao)護(hu)(hu)(hu)閾值降為4.2V。當(dang)檢(jian)測(ce)到(dao)IGBT過(guo)(guo)流(liu)后,5引腳變為低電(dian)(dian)平,TPL521型光耦輸(shu)出(chu)低電(dian)(dian)平,通(tong)過(guo)(guo)與門(men)控制信號(hao)輸(shu)入,同時(shi)(shi)使4輸(shu)入與非門(men)輸(shu)出(chu)低電(dian)(dian)平,觸發功率驅(qu)動(dong)(dong)保(bao)(bao)護(hu)(hu)(hu)中斷(duan),完成相應的(de)(de)保(bao)(bao)護(hu)(hu)(hu)處理(li)。

1.5 控制部(bu)(bu)分與驅動部(bu)(bu)分的(de)隔離

　　控(kong)制(zhi)電(dian)(dian)路(lu)(lu)(lu)為(wei)(wei)弱(ruo)電(dian)(dian)部分(fen),極易(yi)受到干(gan)擾(rao);驅動(dong)電(dian)(dian)路(lu)(lu)(lu)直(zhi)接(jie)與外(wai)電(dian)(dian)路(lu)(lu)(lu)連接(jie),是一個(ge)較強的(de)干(gan)擾(rao)源(yuan)(yuan);為(wei)(wei)了實現整(zheng)個(ge)設備的(de)電(dian)(dian)磁兼容(rong),控(kong)制(zhi)電(dian)(dian)路(lu)(lu)(lu)部分(fen)必須與驅動(dong)部分(fen)隔離(li)。為(wei)(wei)了避(bi)免公共電(dian)(dian)源(yuan)(yuan)對(dui)控(kong)制(zhi)電(dian)(dian)路(lu)(lu)(lu)產生干(gan)擾(rao),應(ying)對(dui)控(kong)制(zhi)電(dian)(dian)路(lu)(lu)(lu)及驅動(dong)電(dian)(dian)路(lu)(lu)(lu)分(fen)別(bie)供電(dian)(dian),EXB84l的(de)電(dian)(dian)源(yuan)(yuan)電(dian)(dian)壓(ya)為(wei)(wei)+20 V,一般控(kong)制(zhi)電(dian)(dian)路(lu)(lu)(lu)的(de)供電(dian)(dian)電(dian)(dian)壓(ya)為(wei)(wei)5 V,因此,可以(yi)利用圖4所示的(de)DC-DC微(wei)功(gong)率模塊進行(xing)電(dian)(dian)源(yuan)(yuan)隔離(li),采用A2405D型(xing)微(wei)功(gong)率模塊實現電(dian)(dian)源(yuan)(yuan)的(de)隔離(li)。

2 IGBT及驅動電路的保護(hu)

2.1 IGBT的過(guo)電壓保護

　　IGBT集(ji)(ji)(ji)-射(she)極之間(jian)(jian)的瞬時(shi)過(guo)(guo)壓(ya)(ya)會對IGBT造成(cheng)損(sun)壞(huai),筆(bi)者采用箝位(wei)式(shi)吸收電(dian)(dian)(dian)路(lu)對瞬時(shi)過(guo)(guo)電(dian)(dian)(dian)壓(ya)(ya)進(jin)行(xing)抑制。當IGBT導通(tong)時(shi),由(you)于二(er)極管的作用,電(dian)(dian)(dian)容器(qi)(qi)的電(dian)(dian)(dian)荷不(bu)會被放(fang)掉,電(dian)(dian)(dian)容器(qi)(qi)電(dian)(dian)(dian)壓(ya)(ya)仍為電(dian)(dian)(dian)源電(dian)(dian)(dian)壓(ya)(ya)。IGBT關斷時(shi),負載(zai)電(dian)(dian)(dian)流仍流過(guo)(guo)IGBT,直到IGBT集(ji)(ji)(ji)-射(she)極之間(jian)(jian)電(dian)(dian)(dian)壓(ya)(ya)達到電(dian)(dian)(dian)源電(dian)(dian)(dian)壓(ya)(ya),續流二(er)極管導通(tong)。應用該(gai)電(dian)(dian)(dian)路(lu),可以(yi)使雜(za)散電(dian)(dian)(dian)感中的能(neng)量通(tong)過(guo)(guo)二(er)極管轉儲到吸收電(dian)(dian)(dian)容器(qi)(qi)中,而IGBT的集(ji)(ji)(ji)電(dian)(dian)(dian)極電(dian)(dian)(dian)位(wei)被箝位(wei)在電(dian)(dian)(dian)容電(dian)(dian)(dian)壓(ya)(ya)上,這樣就(jiu)可以(yi)抑制IGBT集(ji)(ji)(ji)電(dian)(dian)(dian)極的尖峰電(dian)(dian)(dian)壓(ya)(ya)。吸收電(dian)(dian)(dian)容器(qi)(qi)的容值可以(yi)按公式(shi)(2)選取：

　　式中,L是引(yin)線電感;i是IGBT關斷時的(de)電流;△U是吸收電容器上的(de)電壓過沖。

　　當吸(xi)(xi)(xi)(xi)(xi)收(shou)(shou)回(hui)路(lu)(lu)中的(de)(de)(de)電(dian)(dian)(dian)容(rong)(rong)(rong)器(qi)(qi)電(dian)(dian)(dian)壓(ya)(ya)(ya)高于(yu)直(zhi)(zhi)流側(ce)(ce)電(dian)(dian)(dian)容(rong)(rong)(rong)器(qi)(qi)上(shang)的(de)(de)(de)電(dian)(dian)(dian)壓(ya)(ya)(ya)時(shi)(shi),通過電(dian)(dian)(dian)阻(zu)器(qi)(qi)向(xiang)直(zhi)(zhi)流側(ce)(ce)電(dian)(dian)(dian)容(rong)(rong)(rong)器(qi)(qi)回(hui)送能量(liang),一直(zhi)(zhi)到(dao)與直(zhi)(zhi)流側(ce)(ce)電(dian)(dian)(dian)容(rong)(rong)(rong)器(qi)(qi)的(de)(de)(de)電(dian)(dian)(dian)壓(ya)(ya)(ya)相等(deng)。當IGBT關斷時(shi)(shi),線路(lu)(lu)電(dian)(dian)(dian)感在集電(dian)(dian)(dian)極和發射極二端產生很高的(de)(de)(de)尖峰(feng)電(dian)(dian)(dian)壓(ya)(ya)(ya),加上(shang)箝位式吸(xi)(xi)(xi)(xi)(xi)收(shou)(shou)電(dian)(dian)(dian)路(lu)(lu)以后,UCE被箝位在電(dian)(dian)(dian)容(rong)(rong)(rong)器(qi)(qi)電(dian)(dian)(dian)壓(ya)(ya)(ya)上(shang),當UCE高于(yu)電(dian)(dian)(dian)容(rong)(rong)(rong)器(qi)(qi)電(dian)(dian)(dian)壓(ya)(ya)(ya)時(shi)(shi),線路(lu)(lu)電(dian)(dian)(dian)感的(de)(de)(de)能量(liang)被轉移到(dao)吸(xi)(xi)(xi)(xi)(xi)收(shou)(shou)電(dian)(dian)(dian)容(rong)(rong)(rong)器(qi)(qi)上(shang),當尖峰(feng)電(dian)(dian)(dian)壓(ya)(ya)(ya)過去以后,吸(xi)(xi)(xi)(xi)(xi)收(shou)(shou)電(dian)(dian)(dian)容(rong)(rong)(rong)高于(yu)主電(dian)(dian)(dian)容(rong)(rong)(rong)的(de)(de)(de)那部分電(dian)(dian)(dian)壓(ya)(ya)(ya)會由于(yu)能量(liang)回(hui)進而達到(dao)與主電(dian)(dian)(dian)容(rong)(rong)(rong)相等(deng)。這樣就抑制了(le)集-射極間的(de)(de)(de)尖峰(feng)電(dian)(dian)(dian)壓(ya)(ya)(ya)。吸(xi)(xi)(xi)(xi)(xi)收(shou)(shou)電(dian)(dian)(dian)容(rong)(rong)(rong)越大(da),吸(xi)(xi)(xi)(xi)(xi)收(shou)(shou)效果越好。由于(yu)吸(xi)(xi)(xi)(xi)(xi)收(shou)(shou)電(dian)(dian)(dian)容(rong)(rong)(rong)器(qi)(qi)上(shang)過沖(chong)的(de)(de)(de)能量(liang)大(da)部分被送回(hui)到(dao)直(zhi)(zhi)流側(ce)(ce)電(dian)(dian)(dian)容(rong)(rong)(rong),所(suo)以減小了(le)電(dian)(dian)(dian)阻(zu)器(qi)(qi)的(de)(de)(de)功耗。

2.2 消除IGBT集-柵(zha)極之(zhi)間的du/dt

　　圖(tu)5所示為(wei)EXB841與IGBT柵(zha)-射極(ji)之(zhi)(zhi)間(jian)(jian)(jian)的(de)(de)(de)(de)連接(jie)電(dian)(dian)(dian)路(lu)原(yuan)理圖(tu)。當驅動電(dian)(dian)(dian)路(lu)中的(de)(de)(de)(de)V4導(dao)(dao)通(tong)(tong)時(shi)(shi)(shi),IGBT處(chu)于正(zheng)常導(dao)(dao)通(tong)(tong)狀態(tai)(tai),當V5導(dao)(dao)通(tong)(tong)時(shi)(shi)(shi),IGBT柵(zha)-射極(ji)之(zhi)(zhi)間(jian)(jian)(jian)通(tong)(tong)過(guo)穩壓(ya)管VZ2提供(gong)一(yi)個-5V電(dian)(dian)(dian)壓(ya)加(jia)在其兩端(duan),使(shi)IGBT關斷,此時(shi)(shi)(shi)V5處(chu)于臨界導(dao)(dao)通(tong)(tong)狀態(tai)(tai),穩壓(ya)管VZ2處(chu)于反向(xiang)偏置(zhi)狀態(tai)(tai)。但由于集(ji)-柵(zha)極(ji)之(zhi)(zhi)間(jian)(jian)(jian)分(fen)布電(dian)(dian)(dian)容(rong)的(de)(de)(de)(de)影響,集(ji)-柵(zha)極(ji)之(zhi)(zhi)間(jian)(jian)(jian)的(de)(de)(de)(de)du/dt增大(da)時(shi)(shi)(shi),其通(tong)(tong)過(guo)分(fen)布電(dian)(dian)(dian)容(rong)形成(cheng)的(de)(de)(de)(de)電(dian)(dian)(dian)流經過(guo),所以(yi),要克服(fu)集(ji)-柵(zha)極(ji)之(zhi)(zhi)間(jian)(jian)(jian)的(de)(de)(de)(de)du/dt,確保穩壓(ya)管不過(guo)壓(ya),避免IGBT誤導(dao)(dao)通(tong)(tong)。克服(fu)du/dt的(de)(de)(de)(de)方(fang)法有二種：一(yi)是驅動電(dian)(dian)(dian)路(lu)輸出與IGBT柵(zha)-射極(ji)之(zhi)(zhi)間(jian)(jian)(jian)的(de)(de)(de)(de)連線(xian)采用(yong)雙絞(jiao)屏蔽(bi)電(dian)(dian)(dian)纜(lan),屏蔽(bi)層接(jie)地,二是采用(yong)快(kuai)速吸收電(dian)(dian)(dian)路(lu)吸收過(guo)電(dian)(dian)(dian)壓(ya)。

2.3 EXB841的(de)過(guo)流保護功能擴展

　　EXB841自身具有(you)過(guo)流(liu)保護功能(neng),其(qi)保護原理是利用IGBT的(de)(de)(de)集(ji)(ji)電(dian)極通態飽和(he)壓(ya)(ya)降(jiang)與集(ji)(ji)電(dian)極電(dian)流(liu)呈近(jin)似線性關系。當IGBT工作在(zai)正常(chang)狀態時,EXB841的(de)(de)(de)6腳(jiao)電(dian)位箝制在(zai)8 V,內(nei)部保護不動作,當IGBT因承(cheng)受過(guo)流(liu)而退出(chu)飽和(he)狀態時,IGBT集(ji)(ji)-射極間的(de)(de)(de)電(dian)壓(ya)(ya)上升很(hen)多,與EXB84l的(de)(de)(de)6引腳(jiao)相連的(de)(de)(de)快速二極管截(jie)止,EXB841的(de)(de)(de)6引腳(jiao)被懸空,內(nei)部保護動作,輸出(chu)驅動電(dian)壓(ya)(ya)慢慢下降(jiang),實現IGBT的(de)(de)(de)軟關斷(duan)。

　　在(zai)(zai)(zai)實際應用中(zhong)(zhong),僅靠(kao)EXB841的(de)6引腳檢(jian)測IG-BT集電(dian)(dian)極(ji)電(dian)(dian)壓來實現過(guo)流(liu)(liu)保護并不足以有效(xiao)地保護IGBT,因此(ci)有必要在(zai)(zai)(zai)主電(dian)(dian)路中(zhong)(zhong)加接(jie)霍(huo)爾(er)電(dian)(dian)流(liu)(liu)傳感(gan)器(qi)來檢(jian)測電(dian)(dian)路中(zhong)(zhong)的(de)過(guo)流(liu)(liu),如圖6所示。過(guo)流(liu)(liu)發生后,檢(jian)測電(dian)(dian)路檢(jian)測到(dao)電(dian)(dian)流(liu)(liu),延(yan)時8μs后信(xin)號(hao)還(huan)存在(zai)(zai)(zai)的(de)話。驅動信(xin)號(hao)以關(guan)斷IGBT。在(zai)(zai)(zai)圖中(zhong)(zhong),霍(huo)爾(er)電(dian)(dian)流(liu)(liu)傳感(gan)器(qi)如果在(zai)(zai)(zai)主電(dian)(dian)路中(zhong)(zhong)檢(jian)測到(dao)過(guo)流(liu)(liu)信(xin)號(hao),其中(zhong)(zhong)的(de)PNP三(san)極(ji)管將導通(tong),同時,NPN三(san)極(ji)管被截止,EXB841的(de)6腳被懸空;當(dang)沒有過(guo)流(liu)(liu)信(xin)號(hao)時,PNP三(san)極(ji)管不導通(tong),NPN三(san)極(ji)管導通(tong),此(ci)時電(dian)(dian)路等效(xiao)于(yu)擴展前(qian)的(de)電(dian)(dian)路。

3 結束語

　　本(ben)設(she)計應用以上電(dian)路對(dui)IGBT進行(xing)驅(qu)(qu)(qu)動和保護(hu)。此驅(qu)(qu)(qu)動電(dian)路是(shi)在(zai)典型驅(qu)(qu)(qu)動電(dian)路的基礎上進行(xing)改(gai)進和完(wan)善(shan)的,并且自行(xing)設(she)計了隔離部(bu)分(fen)和過電(dian)流保護(hu)擴展部(bu)分(fen)。此驅(qu)(qu)(qu)動電(dian)路相對(dui)簡單、實用,對(dui)被驅(qu)(qu)(qu)動的IGBT有(you)完(wan)善(shan)的保護(hu)能力(li),輸出阻抗低,具有(you)較強的抗干(gan)擾性能。

　　應用這種IGBT模塊(kuai)的有源濾波器的樣機(ji)通(tong)過試驗,證(zheng)明(ming)硬(ying)件能夠協(xie)調配(pei)合,控(kong)制效果穩(wen)定、精確,并且(qie)已經批量制板(ban)。