實驗名稱：方波脈沖(chong)電場下聚酰亞胺空間電荷的直接檢測技術研(yan)究(jiu)

　　研究方向：聚酰亞(ya)(ya)胺(an)薄膜因其優(you)異的(de)(de)電(dian)(dian)(dian)(dian)氣性(xing)能，在(zai)變頻調速(su)電(dian)(dian)(dian)(dian)機絕緣系統(tong)中得到廣(guang)泛應用。然(ran)而，方波(bo)(bo)(bo)電(dian)(dian)(dian)(dian)場極(ji)性(xing)反轉的(de)(de)快(kuai)速(su)過程（ns-μs級）給直接檢測介質(zhi)內(nei)(nei)部空(kong)(kong)間電(dian)(dian)(dian)(dian)荷帶來挑(tiao)戰。本文采用電(dian)(dian)(dian)(dian)聲脈沖法，通過優(you)化系統(tong)參數，實現(xian)了(le)(le)方波(bo)(bo)(bo)電(dian)(dian)(dian)(dian)場下空(kong)(kong)間電(dian)(dian)(dian)(dian)荷的(de)(de)直接動態(tai)檢測，相位(wei)分(fen)辨率達1.79°，并降低(di)了(le)(le)電(dian)(dian)(dian)(dian)壓(ya)波(bo)(bo)(bo)形(xing)失真。研究(jiu)發現(xian)，未熱處理的(de)(de)聚酰亞(ya)(ya)胺(an)在(zai)直流電(dian)(dian)(dian)(dian)場下存在(zai)雙載流子注入和深陷阱注入，導(dao)致空(kong)(kong)間電(dian)(dian)(dian)(dian)荷長時間積聚。而在(zai)方波(bo)(bo)(bo)電(dian)(dian)(dian)(dian)場下，空(kong)(kong)間電(dian)(dian)(dian)(dian)荷主要來自(zi)下電(dian)(dian)(dian)(dian)極(ji)鋁(lv)板注入的(de)(de)同極(ji)性(xing)電(dian)(dian)(dian)(dian)荷，電(dian)(dian)(dian)(dian)壓(ya)極(ji)性(xing)反轉時可快(kuai)速(su)抽出，無(wu)明顯積累(lei)。熱處理可能破壞(huai)聚酰亞(ya)(ya)胺(an)分(fen)子鏈(lian)，影(ying)響表面形(xing)貌并增大高頻段介電(dian)(dian)(dian)(dian)常數，但對(dui)(dui)耐擊穿性(xing)能影(ying)響不明顯。熱處理減(jian)弱(ruo)了(le)(le)直流電(dian)(dian)(dian)(dian)場下的(de)(de)正極(ji)性(xing)電(dian)(dian)(dian)(dian)荷注入，加速(su)了(le)(le)空(kong)(kong)間電(dian)(dian)(dian)(dian)荷耗散，但對(dui)(dui)方波(bo)(bo)(bo)電(dian)(dian)(dian)(dian)場下的(de)(de)空(kong)(kong)間電(dian)(dian)(dian)(dian)荷分(fen)布(bu)影(ying)響有限(xian)。此(ci)外，上(shang)升沿(yan)時間在(zai)100μs-1000μs范(fan)圍內(nei)(nei)對(dui)(dui)空(kong)(kong)間電(dian)(dian)(dian)(dian)荷積累(lei)量(liang)和位(wei)置分(fen)布(bu)基本無(wu)影(ying)響。

　　實驗目的：方波脈沖電場下聚酰亞(ya)胺空(kong)間電荷的直(zhi)接(jie)檢(jian)測

　　測試設備：函數發生器，高壓放大器，高壓高頻脈沖源，分(fen)壓器(qi)，數字示波器(qi)，計(ji)算機

　　實驗過程：輸(shu)(shu)出信號(hao)設置(zhi)為(wei)方波波形(xing)時(shi)(shi)(shi)，頻(pin)率(lv)范(fan)圍(wei)為(wei)1μHz至(zhi)50MHz，方波上(shang)升沿(yan)下降沿(yan)時(shi)(shi)(shi)間不超過5ns。雙通道函(han)數(shu)發(fa)(fa)生器(qi)(qi)一(yi)路(lu)輸(shu)(shu)出頻(pin)率(lv)和(he)幅值均可調的(de)任意周期(qi)(qi)電(dian)(dian)壓(ya)(ya)信號(hao)，經高(gao)(gao)壓(ya)(ya)放(fang)大(da)(da)器(qi)(qi)后施加到(dao)待測(ce)試(shi)樣(yang)上(shang)。高(gao)(gao)壓(ya)(ya)放(fang)大(da)(da)器(qi)(qi)最高(gao)(gao)輸(shu)(shu)出電(dian)(dian)壓(ya)(ya)為(wei)20kV,函(han)數(shu)發(fa)(fa)生器(qi)(qi)另一(yi)路(lu)輸(shu)(shu)出周期(qi)(qi)性(xing)的(de)TTL時(shi)(shi)(shi)間信號(hao)，同(tong)時(shi)(shi)(shi)控制高(gao)(gao)壓(ya)(ya)高(gao)(gao)頻(pin)脈(mo)(mo)(mo)(mo)沖(chong)(chong)源(yuan)(yuan)產生脈(mo)(mo)(mo)(mo)沖(chong)(chong)激(ji)勵和(he)觸(chu)發(fa)(fa)數(shu)字示波器(qi)(qi)采集(ji)。高(gao)(gao)頻(pin)高(gao)(gao)壓(ya)(ya)脈(mo)(mo)(mo)(mo)沖(chong)(chong)源(yuan)(yuan)也(ye)為(wei)實(shi)驗室(shi)自主研發(fa)(fa)裝(zhuang)置(zhi)，設置(zhi)為(wei)在TTL上(shang)升沿(yan)時(shi)(shi)(shi)觸(chu)發(fa)(fa)，每(mei)次觸(chu)發(fa)(fa)輸(shu)(shu)出一(yi)個脈(mo)(mo)(mo)(mo)寬可調（5ns-20ns）的(de)高(gao)(gao)頻(pin)脈(mo)(mo)(mo)(mo)沖(chong)(chong)激(ji)勵，脈(mo)(mo)(mo)(mo)沖(chong)(chong)幅值最大(da)(da)可達2.5kV，重復頻(pin)率(lv)最高(gao)(gao)為(wei)3kHz。高(gao)(gao)壓(ya)(ya)脈(mo)(mo)(mo)(mo)沖(chong)(chong)經保(bao)護電(dian)(dian)容(rong)耦合(he)到(dao)被測(ce)試(shi)樣(yang)上(shang)，保(bao)護電(dian)(dian)容(rong)的(de)最主要作用是防止(zhi)高(gao)(gao)壓(ya)(ya)放(fang)大(da)(da)器(qi)(qi)輸(shu)(shu)出傳(chuan)遞到(dao)脈(mo)(mo)(mo)(mo)沖(chong)(chong)源(yuan)(yuan)測(ce)造成(cheng)設備(bei)(bei)損壞(huai)。示波器(qi)(qi)采用具備(bei)(bei)大(da)(da)數(shu)據量(liang)保(bao)存功能的(de)數(shu)字示波器(qi)(qi)，也(ye)采用TTL上(shang)升沿(yan)觸(chu)發(fa)(fa)，這樣(yang)就可保(bao)證(zheng)每(mei)次脈(mo)(mo)(mo)(mo)沖(chong)(chong)激(ji)勵產生的(de)空間電(dian)(dian)荷(he)信號(hao)都能被保(bao)存下來(lai)。PEA電(dian)(dian)極(ji)系統是由(you)實(shi)驗室(shi)自主研發(fa)(fa)搭(da)建的(de)系統，其中上(shang)電(dian)(dian)極(ji)材料為(wei)半導(dao)電(dian)(dian)，下電(dian)(dian)極(ji)采用鋁電(dian)(dian)極(ji)。PVDF壓(ya)(ya)電(dian)(dian)傳(chuan)感器(qi)(qi)將電(dian)(dian)荷(he)受激(ji)振動產生的(de)聲信號(hao)轉變(bian)為(wei)電(dian)(dian)信號(hao)，通過放(fang)大(da)(da)器(qi)(qi)傳(chuan)送(song)到(dao)示波器(qi)(qi)進行讀取和(he)保(bao)存，示波器(qi)(qi)同(tong)時(shi)(shi)(shi)記錄該(gai)時(shi)(shi)(shi)刻施加到(dao)試(shi)樣(yang)上(shang)的(de)電(dian)(dian)壓(ya)(ya)以便后期(qi)(qi)數(shu)據處理。

　　圖1-1：實(shi)驗(yan)流程框(kuang)圖

　　實驗結果：本文中方(fang)波(bo)(bo)電場頻率fa=50Hz，根據(ju)AEPS原理(li)的(de)特(te)征方(fang)程，將脈沖(chong)(chong)激(ji)勵的(de)頻率設(she)(she)置為(wei)(wei)(wei)fp=2010Hz，則出(chu)現檢測(ce)相(xiang)(xiang)(xiang)位(wei)(wei)(wei)重復(fu)的(de)最少方(fang)波(bo)(bo)周(zhou)(zhou)期(qi)(qi)數Na為(wei)(wei)(wei)5，該(gai)時(shi)間段內出(chu)現的(de)脈沖(chong)(chong)數Np為(wei)(wei)(wei)201，根據(ju)相(xiang)(xiang)(xiang)位(wei)(wei)(wei)分(fen)(fen)辨(bian)(bian)率公式(2-4)可(ke)知相(xiang)(xiang)(xiang)位(wei)(wei)(wei)分(fen)(fen)辨(bian)(bian)率Δ'約為(wei)(wei)(wei)1.79°。通(tong)過(guo)圖可(ke)以更好的(de)說明AEPS的(de)測(ce)量(liang)原理(li)。方(fang)波(bo)(bo)頻率為(wei)(wei)(wei)50Hz，脈沖(chong)(chong)激(ji)勵頻率為(wei)(wei)(wei)2010Hz，則在(zai)一(yi)(yi)個(ge)(ge)(ge)方(fang)波(bo)(bo)周(zhou)(zhou)期(qi)(qi)里(li)(li)有2010/50=40.2個(ge)(ge)(ge)脈沖(chong)(chong)激(ji)勵，一(yi)(yi)個(ge)(ge)(ge)方(fang)波(bo)(bo)周(zhou)(zhou)期(qi)(qi)里(li)(li)包含有40個(ge)(ge)(ge)不(bu)重復(fu)的(de)脈沖(chong)(chong)激(ji)勵。假設(she)(she)第(di)(di)一(yi)(yi)個(ge)(ge)(ge)方(fang)波(bo)(bo)周(zhou)(zhou)期(qi)(qi)開始時(shi)脈沖(chong)(chong)在(zai)0°相(xiang)(xiang)(xiang)位(wei)(wei)(wei)位(wei)(wei)(wei)置，那么第(di)(di)41個(ge)(ge)(ge)脈沖(chong)(chong)信(xin)號(hao)對應(ying)的(de)方(fang)波(bo)(bo)相(xiang)(xiang)(xiang)位(wei)(wei)(wei)為(wei)(wei)(wei)41/2010*50*360=367.16°，也即7.16°。從41至80這四十個(ge)(ge)(ge)脈沖(chong)(chong)信(xin)號(hao)都(dou)對應(ying)在(zai)第(di)(di)二個(ge)(ge)(ge)方(fang)波(bo)(bo)周(zhou)(zhou)期(qi)(qi)里(li)(li)，且與第(di)(di)一(yi)(yi)個(ge)(ge)(ge)周(zhou)(zhou)期(qi)(qi)里(li)(li)的(de)脈沖(chong)(chong)對應(ying)的(de)相(xiang)(xiang)(xiang)位(wei)(wei)(wei)都(dou)不(bu)重復(fu)。類似的(de)第(di)(di)81個(ge)(ge)(ge)脈沖(chong)(chong)信(xin)號(hao)對應(ying)的(de)相(xiang)(xiang)(xiang)位(wei)(wei)(wei)為(wei)(wei)(wei)5.37°，第(di)(di)121個(ge)(ge)(ge)脈沖(chong)(chong)信(xin)號(hao)對應(ying)的(de)相(xiang)(xiang)(xiang)位(wei)(wei)(wei)為(wei)(wei)(wei)3.58°，第(di)(di)161個(ge)(ge)(ge)脈沖(chong)(chong)信(xin)號(hao)對應(ying)1相(xiang)(xiang)(xiang)位(wei)(wei)(wei)

　　圖1-2：方波電(dian)場(chang)下(xia)AEPS采集示意(yi)圖

　　產(chan)品推薦：ATA-7100高壓放(fang)大(da)器

　　圖：ATA-7100高壓放大器指標參數

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