ANAPF有源電力濾波器

1、ANAPF產品介紹

ANAPF 模塊工(gong)作原理(li)

ANAPF 系列有源電(dian)(dian)(dian)(dian)力(li)濾波(bo)器并聯在含諧(xie)波(bo)負載(zai)的(de)(de)低壓(ya)配電(dian)(dian)(dian)(dian)系統中(zhong)，能(neng)夠對動態變化的(de)(de)諧(xie)波(bo)電(dian)(dian)(dian)(dian)流(liu)進行(xing)快(kuai)速(su)實 時的(de)(de)跟(gen)蹤和補償。其原(yuan)理為：ANAPF 系列有源電(dian)(dian)(dian)(dian)力(li)濾波(bo)器通過(guo) CT 采集系統諧(xie)波(bo)電(dian)(dian)(dian)(dian)流(liu)，經控制器快(kuai)速(su)計算并提取(qu) 各(ge)次諧(xie)波(bo)電(dian)(dian)(dian)(dian)流(liu)的(de)(de)含量，產生諧(xie)波(bo)電(dian)(dian)(dian)(dian)流(liu)指令，通過(guo)功率(lv)執行(xing)器件產生與(yu)諧(xie)波(bo)電(dian)(dian)(dian)(dian)流(liu)幅值相等方(fang)向(xiang)相反(fan)的(de)(de)補償電(dian)(dian)(dian)(dian)流(liu)，并 注入電(dian)(dian)(dian)(dian)力(li)系統中(zhong)，從而(er)抵消非線性(xing)負載(zai)所產生的(de)(de)諧(xie)波(bo)電(dian)(dian)(dian)(dian)流(liu)。

ANAPF 整機工作(zuo)原理

     有源電(dian)(dian)力濾(lv)波器(qi)是一種用于諧波治理、補(bu)償(chang)(chang)無(wu)功以及不平(ping)衡調節的(de)(de)新型電(dian)(dian)力電(dian)(dian)子裝置；智能控制系統主動根據系 統的(de)(de)線(xian)性動態需求，自動調節模(mo)塊的(de)(de)輸出；ANAPF整(zheng)機(ji)主要是由ANAPF模(mo)塊組成；能完成更大容量(liang)的(de)(de)諧波電(dian)(dian)流的(de)(de)補(bu) 償(chang)(chang)，整(zheng)機(ji)通過一個7寸觸摸屏實現人機(ji)交互。觸摸屏通過RS485與(yu)ANAPF模(mo)塊進行通信(xin)。

產品特點

     1) 補(bu)(bu)償(chang)方(fang)式靈活：既可(ke)(ke)補(bu)(bu)諧波(bo)，又可(ke)(ke)兼補(bu)(bu)無(wu)功(gong)，可(ke)(ke)對 2-51 次諧波(bo)進行(xing)(xing)全(quan)補(bu)(bu)償(chang)或特(te)定次諧波(bo)進行(xing)(xing)補(bu)(bu)償(chang)；

     2) 可治理三相不平衡；

     3) 線性補償(chang)，響應(ying)時間≤5ms；

     4) 具有人(ren)(ren)性化的人(ren)(ren)機(ji)交互界面，可通(tong)過該界面看到系統(tong)和本體的實時電能質量信息，操作簡(jian)單，可以(yi)遠(yuan)控，也 可以(yi)本控；

     5) 采用進(jin)口 IGBT，功率密度大(da)，可靠性高；

     6) 采用 DSP 高(gao)速檢測和運算的數字控制系統；

     7) 監(jian)控(kong)(kong)以及顯示具備遠程通訊接口，可以通過(guo) PC 機實時監(jian)控(kong)(kong)；

     8) 標(biao)準模塊化設(she)計，縮短交付周期，同時提高了使用的可靠性和可維護(hu)性。

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)(de)IGBT的(de)(de)特性及其專有(you)EXB84l型驅(qu)動器的(de)(de)設計進行討論(lun),并(bing)提出一(yi)種具(ju)有(you)完善保護功能的(de)(de)驅(qu)動電路。

　　有源電力濾波器設(she)計中應用(yong)4個IGBT作(zuo)為開關,并(bing)用(yong)4個EXB84l組成(cheng)驅動(dong)電(dian)路(lu),其原(yuan)理(li)(li)(li)如圖l所示。在實驗中,根據補(bu)償電(dian)流與(yu)指(zhi)令電(dian)流的(de)關系,用(yong)數字信(xin)號處理(li)(li)(li)器(DSP)控(kong)制(zhi)PWM引腳的(de)高低電(dian)平,并(bing)由驅動(dong)電(dian)路(lu)控(kong)制(zhi)IGBT的(de)通(tong)斷。驅動(dong)電(dian)路(lu)同時(shi)對過(guo)流故障進行(xing)監測,由DSP采取控(kong)制(zhi)信(xin)號、停機(ji)等處理(li)(li)(li)。

圖1 有源電力濾波器的IGBT驅(qu)動電路原理

1 驅動(dong)電路(lu)的設(she)計

1.1 驅動電路電源

　　驅動電(dian)路需(xu)要4路相互(hu)隔離的(de)直流(liu)電(dian)源為4路IGBT驅動電(dian)路供電(dian),用220V/22V變壓(ya)器(qi)(qi)(qi)對4路交流(liu)電(dian)源分別整(zheng)流(liu),用電(dian)容器(qi)(qi)(qi)和78L24型電(dian)壓(ya)調(diao)整(zheng)器(qi)(qi)(qi)穩壓(ya)后輸出4路24V直流(liu)電(dian)壓(ya),如圖2所(suo)示。

圖2 IGBT驅(qu)動電路的電源設計

1.2 柵極電壓

　　IGBT通(tong)(tong)常(chang)采用柵極(ji)(ji)電(dian)壓(ya)(ya)驅動(dong)(dong)(dong)(dong)(dong),它(ta)對柵極(ji)(ji)驅動(dong)(dong)(dong)(dong)(dong)電(dian)路有著特殊的(de)要(yao)求(qiu)。柵極(ji)(ji)驅動(dong)(dong)(dong)(dong)(dong)電(dian)壓(ya)(ya)脈沖的(de)上升(sheng)率(lv)和(he)(he)下(xia)(xia)降(jiang)率(lv)要(yao)足(zu)夠大,導(dao)通(tong)(tong)時(shi),前(qian)沿很(hen)陡(dou)的(de)柵極(ji)(ji)電(dian)壓(ya)(ya)UGE可(ke)(ke)以(yi)(yi)使(shi)IGBT快速導(dao)通(tong)(tong),并減小導(dao)通(tong)(tong)損(sun)耗(hao),關(guan)(guan)斷時(shi),其柵極(ji)(ji)驅動(dong)(dong)(dong)(dong)(dong)電(dian)路要(yao)給IGBT提供一個(ge)下(xia)(xia)降(jiang)很(hen)陡(dou)的(de)關(guan)(guan)斷電(dian)壓(ya)(ya),并在柵極(ji)(ji)和(he)(he)發射極(ji)(ji)之間(jian)施加一個(ge)適當的(de)反向負(fu)偏壓(ya)(ya),以(yi)(yi)便(bian)使(shi)IGBT快速關(guan)(guan)斷,并減小關(guan)(guan)斷損(sun)耗(hao)。IGBT導(dao)通(tong)(tong)后,柵極(ji)(ji)的(de)驅動(dong)(dong)(dong)(dong)(dong)電(dian)壓(ya)(ya)和(he)(he)電(dian)流(liu)要(yao)有足(zu)夠的(de)寬度(du),以(yi)(yi)保證IGBT在瞬時(shi)過載時(shi)未(wei)退出飽和(he)(he)區受到損(sun)壞。柵極(ji)(ji)驅動(dong)(dong)(dong)(dong)(dong)電(dian)壓(ya)(ya)值為15 V±1.5 V,這個(ge)電(dian)壓(ya)(ya)值使(shi)IGBT*飽和(he)(he)導(dao)通(tong)(tong),并使(shi)通(tong)(tong)態損(sun)耗(hao)減至(zhi)小。施加關(guan)(guan)斷負(fu)偏壓(ya)(ya)可(ke)(ke)以(yi)(yi)抑制(zhi)C-E間(jian)出現du/dt時(shi)IGBT的(de)誤(wu)導(dao)通(tong)(tong),也可(ke)(ke)以(yi)(yi)減少關(guan)(guan)斷損(sun)耗(hao)。

1.3 門極(ji)電阻R1

　　門(men)極(ji)(ji)電阻(zu)R1的選取對通(tong)(tong)(tong)態電壓、開(kai)關時間、開(kai)關損耗及承受短路的能力(li)都有(you)不(bu)同程度的影(ying)響。當門(men)極(ji)(ji)電阻(zu)增大時,IGBT的開(kai)通(tong)(tong)(tong)和關斷時間增加(jia),從而(er)使導(dao)通(tong)(tong)(tong)和關斷損耗增加(jia)。當門(men)極(ji)(ji)電阻(zu)減(jian)小時,則會導(dao)致di/dt增加(jia),從而(er)引起IGBT的誤導(dao)通(tong)(tong)(tong)。所以(yi)應根(gen)據IGBT的電流(liu)容量(liang)和電壓額(e)定值(zhi)以(yi)及開(kai)關頻率的不(bu)同選擇R1的阻(zu)值(zhi)。

　　Rl的值可以用下式計算：

　　IC為IGBT的(de)集(ji)電(dian)(dian)極(ji)電(dian)(dian)流。如圖3所(suo)示,一般R1取(qu)十幾歐姆(mu)到幾十歐姆(mu),R2為30 Ω。由于(yu)IGBT是壓(ya)控器(qi)件,當集(ji)-射(she)(she)極(ji)間加高壓(ya)時(shi),很容易(yi)受(shou)外界干擾,而使(shi)柵-射(she)(she)極(ji)間電(dian)(dian)壓(ya)超過一定(ding)值,引起器(qi)件誤導通,為了防止這種現象的(de)發生,在柵-射(she)(she)極(ji)間并(bing)聯一電(dian)(dian)阻器(qi)R6可起到一定(ding)作用。一般R6阻值是R2阻值的(de)l 000~5 000倍(bei),而且(qie)應將(jiang)它并(bing)聯在柵-射(she)(she)極(ji)近處。電(dian)(dian)路中的(de)電(dian)(dian)容器(qi)Cl和C2用來抑(yi)制因(yin)電(dian)(dian)源接線阻抗引起的(de)供電(dian)(dian)電(dian)(dian)壓(ya)變化,而不(bu)是用于(yu)電(dian)(dian)源濾波。

1.4 EXB841驅動環節

　　筆(bi)者(zhe)在實驗中(zhong)采用的是(shi)EXB841型(xing)IGBT驅(qu)動模塊,其高(gao)運行頻率為(wei)40 kHz,輸入信號(hao)經內部光(guang)耦隔(ge)離(li),光(guang)隔(ge)驅(qu)動電(dian)(dian)流為(wei)10 mA,大延(yan)時(shi)約(yue)為(wei)1 μs。工(gong)作(zuo)溫度范(fan)圍為(wei)-10℃~+85℃,供電(dian)(dian)電(dian)(dian)壓為(wei)+20 V～+25 V。筆(bi)者(zhe)對EXB841功能進行了擴展,圖3為(wei)驅(qu)動環節電(dian)(dian)路。

圖3 有源電力濾波器的(de)IGBT驅動電(dian)路圖

　　EXB841的(de)6引(yin)腳連接(jie)的(de)二極(ji)管(guan)(guan)(guan)可檢(jian)測(ce)(ce)IGBT的(de)飽和(he)壓(ya)降,用(yong)來完成過(guo)流(liu)保(bao)(bao)護(hu)(hu)功能(neng),4引(yin)腳的(de)過(guo)流(liu)保(bao)(bao)護(hu)(hu)信號延時10μs輸出。當IGBT有過(guo)流(liu)時,若UCE大于7.5V,內部(bu)過(guo)流(liu)保(bao)(bao)護(hu)(hu)電(dian)(dian)路開始動作,軟關(guan)斷(duan)(duan)IG-BT。通(tong)常在IGBT通(tong)過(guo)額(e)定(ding)電(dian)(dian)流(liu)時UCE為(wei)3.5 V,當UCE=7.5 V時,IGBT有過(guo)流(liu),其值(zhi)(zhi)約為(wei)額(e)定(ding)電(dian)(dian)流(liu)的(de)3~5倍,但是由于沒有達到保(bao)(bao)護(hu)(hu)的(de)閾(yu)值(zhi)(zhi),保(bao)(bao)護(hu)(hu)電(dian)(dian)路不起作用(yong)。如果長時間工作在這種狀(zhuang)態(tai),則會導致IGBT損壞(huai)。為(wei)了可靠地(di)保(bao)(bao)護(hu)(hu)IGBT,應該(gai)降低(di)過(guo)流(liu)保(bao)(bao)護(hu)(hu)閾(yu)值(zhi)(zhi),可以在D1與IGBT的(de)集電(dian)(dian)極(ji)間反(fan)(fan)串(chuan)(chuan)一個(ge)穩(wen)壓(ya)管(guan)(guan)(guan),或多串(chuan)(chuan)幾(ji)個(ge)與D1同規格的(de)快速恢復二極(ji)管(guan)(guan)(guan)。如圖3通(tong)過(guo)反(fan)(fan)串(chuan)(chuan)一個(ge)IN4728型(xing)3.3 V穩(wen)壓(ya)管(guan)(guan)(guan)使保(bao)(bao)護(hu)(hu)閾(yu)值(zhi)(zhi)降為(wei)4.2V。當檢(jian)測(ce)(ce)到IGBT過(guo)流(liu)后,5引(yin)腳變為(wei)低(di)電(dian)(dian)平,TPL521型(xing)光耦輸出低(di)電(dian)(dian)平,通(tong)過(guo)與門控制信號輸入,同時使4輸入與非(fei)門輸出低(di)電(dian)(dian)平,觸發功率驅動保(bao)(bao)護(hu)(hu)中斷(duan)(duan),完成相(xiang)應的(de)保(bao)(bao)護(hu)(hu)處理。

1.5 控制部分(fen)(fen)與驅動部分(fen)(fen)的(de)隔(ge)離

　　控制(zhi)(zhi)電(dian)路(lu)(lu)為弱電(dian)部(bu)分(fen)(fen),極易受到干擾;驅動電(dian)路(lu)(lu)直接與外電(dian)路(lu)(lu)連(lian)接,是一個較強的(de)(de)干擾源(yuan);為了(le)實現整個設(she)備的(de)(de)電(dian)磁兼(jian)容,控制(zhi)(zhi)電(dian)路(lu)(lu)部(bu)分(fen)(fen)必(bi)須(xu)與驅動部(bu)分(fen)(fen)隔(ge)離(li)。為了(le)避(bi)免公共電(dian)源(yuan)對控制(zhi)(zhi)電(dian)路(lu)(lu)產生(sheng)干擾,應對控制(zhi)(zhi)電(dian)路(lu)(lu)及驅動電(dian)路(lu)(lu)分(fen)(fen)別供電(dian),EXB84l的(de)(de)電(dian)源(yuan)電(dian)壓(ya)為+20 V,一般(ban)控制(zhi)(zhi)電(dian)路(lu)(lu)的(de)(de)供電(dian)電(dian)壓(ya)為5 V,因此,可以利(li)用圖(tu)4所示的(de)(de)DC-DC微功率模塊進行電(dian)源(yuan)隔(ge)離(li),采用A2405D型微功率模塊實現電(dian)源(yuan)的(de)(de)隔(ge)離(li)。

2 IGBT及驅動電路的(de)保護(hu)

2.1 IGBT的過(guo)電壓保護

　　IGBT集(ji)(ji)-射極(ji)之(zhi)間的(de)(de)瞬時(shi)(shi)過(guo)壓(ya)(ya)(ya)(ya)會對IGBT造成損(sun)壞(huai),筆者采用箝(qian)位(wei)(wei)式吸收電(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)對瞬時(shi)(shi)過(guo)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)進行抑制。當IGBT導(dao)通時(shi)(shi),由于二(er)極(ji)管的(de)(de)作用,電(dian)(dian)(dian)(dian)(dian)(dian)(dian)容(rong)(rong)器(qi)的(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)荷(he)不會被放掉,電(dian)(dian)(dian)(dian)(dian)(dian)(dian)容(rong)(rong)器(qi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)仍為電(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)。IGBT關斷時(shi)(shi),負載電(dian)(dian)(dian)(dian)(dian)(dian)(dian)流仍流過(guo)IGBT,直(zhi)到(dao)IGBT集(ji)(ji)-射極(ji)之(zhi)間電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)達到(dao)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya),續流二(er)極(ji)管導(dao)通。應(ying)用該電(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu),可以使雜散電(dian)(dian)(dian)(dian)(dian)(dian)(dian)感中的(de)(de)能(neng)量通過(guo)二(er)極(ji)管轉儲到(dao)吸收電(dian)(dian)(dian)(dian)(dian)(dian)(dian)容(rong)(rong)器(qi)中,而IGBT的(de)(de)集(ji)(ji)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)極(ji)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)位(wei)(wei)被箝(qian)位(wei)(wei)在電(dian)(dian)(dian)(dian)(dian)(dian)(dian)容(rong)(rong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)上,這(zhe)樣就可以抑制IGBT集(ji)(ji)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)極(ji)的(de)(de)尖峰電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)。吸收電(dian)(dian)(dian)(dian)(dian)(dian)(dian)容(rong)(rong)器(qi)的(de)(de)容(rong)(rong)值(zhi)可以按公式(2)選取：

　　式中,L是引線(xian)電(dian)感;i是IGBT關斷(duan)時的(de)電(dian)流;△U是吸收電(dian)容器(qi)上的(de)電(dian)壓過沖。

　　當(dang)(dang)吸(xi)收(shou)(shou)回(hui)路中(zhong)的(de)電(dian)(dian)(dian)(dian)(dian)容(rong)(rong)(rong)(rong)(rong)(rong)器(qi)(qi)(qi)電(dian)(dian)(dian)(dian)(dian)壓高(gao)于直流(liu)側電(dian)(dian)(dian)(dian)(dian)容(rong)(rong)(rong)(rong)(rong)(rong)器(qi)(qi)(qi)上(shang)(shang)的(de)電(dian)(dian)(dian)(dian)(dian)壓時,通過電(dian)(dian)(dian)(dian)(dian)阻(zu)器(qi)(qi)(qi)向直流(liu)側電(dian)(dian)(dian)(dian)(dian)容(rong)(rong)(rong)(rong)(rong)(rong)器(qi)(qi)(qi)回(hui)送(song)能(neng)量,一(yi)直到(dao)(dao)與(yu)直流(liu)側電(dian)(dian)(dian)(dian)(dian)容(rong)(rong)(rong)(rong)(rong)(rong)器(qi)(qi)(qi)的(de)電(dian)(dian)(dian)(dian)(dian)壓相(xiang)等。當(dang)(dang)IGBT關斷(duan)時,線路電(dian)(dian)(dian)(dian)(dian)感(gan)在集電(dian)(dian)(dian)(dian)(dian)極(ji)和發射極(ji)二端產生很高(gao)的(de)尖峰電(dian)(dian)(dian)(dian)(dian)壓,加上(shang)(shang)箝位式吸(xi)收(shou)(shou)電(dian)(dian)(dian)(dian)(dian)路以后,UCE被箝位在電(dian)(dian)(dian)(dian)(dian)容(rong)(rong)(rong)(rong)(rong)(rong)器(qi)(qi)(qi)電(dian)(dian)(dian)(dian)(dian)壓上(shang)(shang),當(dang)(dang)UCE高(gao)于電(dian)(dian)(dian)(dian)(dian)容(rong)(rong)(rong)(rong)(rong)(rong)器(qi)(qi)(qi)電(dian)(dian)(dian)(dian)(dian)壓時,線路電(dian)(dian)(dian)(dian)(dian)感(gan)的(de)能(neng)量被轉移到(dao)(dao)吸(xi)收(shou)(shou)電(dian)(dian)(dian)(dian)(dian)容(rong)(rong)(rong)(rong)(rong)(rong)器(qi)(qi)(qi)上(shang)(shang),當(dang)(dang)尖峰電(dian)(dian)(dian)(dian)(dian)壓過去以后,吸(xi)收(shou)(shou)電(dian)(dian)(dian)(dian)(dian)容(rong)(rong)(rong)(rong)(rong)(rong)高(gao)于主電(dian)(dian)(dian)(dian)(dian)容(rong)(rong)(rong)(rong)(rong)(rong)的(de)那部分(fen)電(dian)(dian)(dian)(dian)(dian)壓會由于能(neng)量回(hui)進而(er)達到(dao)(dao)與(yu)主電(dian)(dian)(dian)(dian)(dian)容(rong)(rong)(rong)(rong)(rong)(rong)相(xiang)等。這(zhe)樣就抑制了集-射極(ji)間(jian)的(de)尖峰電(dian)(dian)(dian)(dian)(dian)壓。吸(xi)收(shou)(shou)電(dian)(dian)(dian)(dian)(dian)容(rong)(rong)(rong)(rong)(rong)(rong)越(yue)大(da),吸(xi)收(shou)(shou)效果越(yue)好(hao)。由于吸(xi)收(shou)(shou)電(dian)(dian)(dian)(dian)(dian)容(rong)(rong)(rong)(rong)(rong)(rong)器(qi)(qi)(qi)上(shang)(shang)過沖的(de)能(neng)量大(da)部分(fen)被送(song)回(hui)到(dao)(dao)直流(liu)側電(dian)(dian)(dian)(dian)(dian)容(rong)(rong)(rong)(rong)(rong)(rong),所以減小了電(dian)(dian)(dian)(dian)(dian)阻(zu)器(qi)(qi)(qi)的(de)功耗。

2.2 消除(chu)IGBT集-柵(zha)極之間的du/dt

　　圖5所示(shi)為EXB841與IGBT柵(zha)(zha)-射(she)(she)極(ji)之間(jian)的(de)(de)(de)連接(jie)電(dian)路(lu)(lu)原(yuan)理圖。當驅動電(dian)路(lu)(lu)中的(de)(de)(de)V4導(dao)通(tong)時(shi),IGBT處(chu)于正(zheng)常導(dao)通(tong)狀(zhuang)態,當V5導(dao)通(tong)時(shi),IGBT柵(zha)(zha)-射(she)(she)極(ji)之間(jian)通(tong)過(guo)穩壓管VZ2提供一(yi)個-5V電(dian)壓加在(zai)其(qi)兩端,使IGBT關斷,此時(shi)V5處(chu)于臨界(jie)導(dao)通(tong)狀(zhuang)態,穩壓管VZ2處(chu)于反向偏置狀(zhuang)態。但(dan)由于集-柵(zha)(zha)極(ji)之間(jian)分布(bu)電(dian)容(rong)的(de)(de)(de)影響(xiang),集-柵(zha)(zha)極(ji)之間(jian)的(de)(de)(de)du/dt增大時(shi),其(qi)通(tong)過(guo)分布(bu)電(dian)容(rong)形成的(de)(de)(de)電(dian)流經過(guo),所以(yi),要克(ke)(ke)服(fu)集-柵(zha)(zha)極(ji)之間(jian)的(de)(de)(de)du/dt,確保穩壓管不過(guo)壓,避(bi)免IGBT誤導(dao)通(tong)。克(ke)(ke)服(fu)du/dt的(de)(de)(de)方法有二種：一(yi)是驅動電(dian)路(lu)(lu)輸出與IGBT柵(zha)(zha)-射(she)(she)極(ji)之間(jian)的(de)(de)(de)連線采(cai)用雙絞屏(ping)蔽(bi)電(dian)纜,屏(ping)蔽(bi)層接(jie)地(di),二是采(cai)用快速吸收電(dian)路(lu)(lu)吸收過(guo)電(dian)壓。

2.3 EXB841的(de)過流保護功能擴(kuo)展

　　EXB841自身(shen)具有(you)過流保(bao)護(hu)(hu)功能,其保(bao)護(hu)(hu)原理是利用(yong)IGBT的(de)(de)(de)集(ji)(ji)電(dian)(dian)極通(tong)態飽和壓降與集(ji)(ji)電(dian)(dian)極電(dian)(dian)流呈近似線性關(guan)系。當(dang)IGBT工作(zuo)在(zai)(zai)正常狀態時,EXB841的(de)(de)(de)6腳電(dian)(dian)位箝制在(zai)(zai)8 V,內部保(bao)護(hu)(hu)不(bu)動(dong)作(zuo),當(dang)IGBT因承受過流而(er)退(tui)出飽和狀態時,IGBT集(ji)(ji)-射極間的(de)(de)(de)電(dian)(dian)壓上升很多,與EXB84l的(de)(de)(de)6引腳相連的(de)(de)(de)快速二極管截止,EXB841的(de)(de)(de)6引腳被懸空,內部保(bao)護(hu)(hu)動(dong)作(zuo),輸出驅動(dong)電(dian)(dian)壓慢慢下降,實現IGBT的(de)(de)(de)軟關(guan)斷。

　　在(zai)實(shi)際應用中(zhong)(zhong),僅靠EXB841的(de)(de)6引腳檢(jian)測(ce)IG-BT集電(dian)極電(dian)壓來實(shi)現過(guo)流(liu)保(bao)護并不(bu)足以(yi)有效地保(bao)護IGBT,因(yin)此有必(bi)要在(zai)主(zhu)電(dian)路(lu)中(zhong)(zhong)加接霍爾(er)電(dian)流(liu)傳感(gan)器來檢(jian)測(ce)電(dian)路(lu)中(zhong)(zhong)的(de)(de)過(guo)流(liu),如(ru)圖6所示。過(guo)流(liu)發(fa)生后,檢(jian)測(ce)電(dian)路(lu)檢(jian)測(ce)到(dao)電(dian)流(liu),延時(shi)(shi)8μs后信(xin)(xin)號還存在(zai)的(de)(de)話。驅動信(xin)(xin)號以(yi)關斷IGBT。在(zai)圖中(zhong)(zhong),霍爾(er)電(dian)流(liu)傳感(gan)器如(ru)果(guo)在(zai)主(zhu)電(dian)路(lu)中(zhong)(zhong)檢(jian)測(ce)到(dao)過(guo)流(liu)信(xin)(xin)號,其(qi)中(zhong)(zhong)的(de)(de)PNP三(san)極管(guan)將導(dao)通,同時(shi)(shi),NPN三(san)極管(guan)被(bei)截(jie)止,EXB841的(de)(de)6腳被(bei)懸空;當沒(mei)有過(guo)流(liu)信(xin)(xin)號時(shi)(shi),PNP三(san)極管(guan)不(bu)導(dao)通,NPN三(san)極管(guan)導(dao)通,此時(shi)(shi)電(dian)路(lu)等效于擴展前(qian)的(de)(de)電(dian)路(lu)。

3 結束語

　　本設(she)計應用(yong)以(yi)上(shang)電路(lu)對IGBT進(jin)行(xing)驅動(dong)(dong)和(he)保(bao)(bao)護(hu)。此(ci)(ci)驅動(dong)(dong)電路(lu)是(shi)在典型驅動(dong)(dong)電路(lu)的(de)基礎上(shang)進(jin)行(xing)改進(jin)和(he)完善的(de),并且自行(xing)設(she)計了隔離部分(fen)和(he)過電流保(bao)(bao)護(hu)擴展部分(fen)。此(ci)(ci)驅動(dong)(dong)電路(lu)相對簡單、實用(yong),對被驅動(dong)(dong)的(de)IGBT有(you)完善的(de)保(bao)(bao)護(hu)能力,輸出阻抗低,具有(you)較強(qiang)的(de)抗干(gan)擾性能。

　　應用這種(zhong)IGBT模(mo)塊的(de)(de)有源濾波器的(de)(de)樣機(ji)通過試驗,證明硬件(jian)能夠協調(diao)配合(he),控制效果穩定、精確,并且已(yi)經批量制板(ban)。