基于高壓陶瓷電容設計的開關電源優勢分析
來源：世紀電源網
摘要：序言現代電(dian)源(yuan)技(ji)術中，無論是線性(xing)電(dian)源(yuan)還是開關(guan)電(dian)源(yuan)，鋁(lv)電(dian)解(jie)電(dian)容都是必不可少(shao)的(de)關(guan)鍵器件。然而，在行業內常規的(de)AC-DC電(dian)源(yuan)設計中，鋁(lv)電(dian)解(jie)電(dian)容會(hui)給(gei)電(dian)源(yuan)帶來高低溫(wen)條件下可靠性(xing)差、壽命(ming)短(duan)等問(wen)題(ti)。那么，有沒有一種(zhong)既能替代傳統鋁(lv)電(dian)解(jie)電(dian)容，又能提高電(dian)源(yuan)可靠性(xing)和...
序(xu) 言
現代電(dian)源(yuan)(yuan)技術中，無論是(shi)(shi)線性(xing)電(dian)源(yuan)(yuan)還是(shi)(shi)開關(guan)電(dian)源(yuan)(yuan)，鋁電(dian)解電(dian)容(rong)(rong)都(dou)是(shi)(shi)必不可少的關(guan)鍵器件。然而，在行業內常規的AC-DC電(dian)源(yuan)(yuan)設(she)計中，鋁電(dian)解電(dian)容(rong)(rong)會(hui)給電(dian)源(yuan)(yuan)帶(dai)來高(gao)低(di)溫條(tiao)件下可靠性(xing)差(cha)、壽命(ming)短等問題。那么，有沒有一種(zhong)既能替代傳統(tong)鋁電(dian)解電(dian)容(rong)(rong)，又能提高(gao)電(dian)源(yuan)(yuan)可靠性(xing)和壽命(ming)的器件呢(ni)？本文著(zhu)重(zhong)從高(gao)壓陶瓷電(dian)容(rong)(rong)與(yu)傳統(tong)鋁電(dian)解電(dian)容(rong)(rong)的優(you)劣勢對比(bi)進行探討與(yu)分(fen)析(xi)。
一、鋁電解(jie)電容的(de)設計(ji)缺陷
AC-DC電(dian)(dian)(dian)(dian)(dian)(dian)源轉換(huan)器，要實(shi)現交(jiao)流(liu)到直(zhi)流(liu)的變換(huan)，首先(xian)需要將交(jiao)流(liu)電(dian)(dian)(dian)(dian)(dian)(dian)壓經過整流(liu)濾波(bo)后形成(cheng)一(yi)個穩定、平(ping)滑的直(zhi)流(liu)電(dian)(dian)(dian)(dian)(dian)(dian)壓給(gei)自身及外(wai)部器件供(gong)電(dian)(dian)(dian)(dian)(dian)(dian)。而電(dian)(dian)(dian)(dian)(dian)(dian)解(jie)(jie)電(dian)(dian)(dian)(dian)(dian)(dian)容(rong)由于(yu)具有(you)單位體積內電(dian)(dian)(dian)(dian)(dian)(dian)容(rong)量大、額定容(rong)量大（可(ke)實(shi)現法拉級(ji)）、價格低(di)廉等優(you)點，常成(cheng)為常規(gui)開關(guan)電(dian)(dian)(dian)(dian)(dian)(dian)源中整流(liu)濾波(bo)的關(guan)鍵器件。電(dian)(dian)(dian)(dian)(dian)(dian)解(jie)(jie)電(dian)(dian)(dian)(dian)(dian)(dian)容(rong)是由鋁圓筒做負極，里(li)面裝有(you)液(ye)(ye)體電(dian)(dian)(dian)(dian)(dian)(dian)解(jie)(jie)質，插入一(yi)片彎曲的鋁帶做正(zheng)極制成(cheng)，電(dian)(dian)(dian)(dian)(dian)(dian)解(jie)(jie)液(ye)(ye)在高溫和(he)(he)低(di)溫等極端條件下，非常容(rong)易漏液(ye)(ye)和(he)(he)干(gan)涸，從而使其電(dian)(dian)(dian)(dian)(dian)(dian)氣屬性發生變化，最終導(dao)(dao)致(zhi)電(dian)(dian)(dian)(dian)(dian)(dian)容(rong)失效。一(yi)旦鋁電(dian)(dian)(dian)(dian)(dian)(dian)解(jie)(jie)電(dian)(dian)(dian)(dian)(dian)(dian)容(rong)失效，因其劇烈反應形成(cheng)壓力，就會釋放出易燃、腐蝕性氣體，導(dao)(dao)致(zhi)失效。
根(gen)據(ju)鋁(lv)電(dian)解電(dian)容(rong)的(de)物理結(jie)構，可以用圖 1中所示的(de)電(dian)路等效(xiao)，其中CAK代(dai)表(biao)兩(liang)電(dian)極間(jian)的(de)理想電(dian)容(rong)量(liang)；Rp 是并聯電(dian)阻，代(dai)表(biao)了電(dian)容(rong)的(de)漏電(dian)流成(cheng)分(fen)(fen)；Rl 代(dai)表(biao)了電(dian)容(rong)引出端(duan)及電(dian)極部分(fen)(fen)的(de)串(chuan)聯電(dian)阻成(cheng)分(fen)(fen)；L 代(dai)表(biao)了引出線和(he)連接處的(de)等效(xiao)串(chuan)聯電(dian)感成(cheng)分(fen)(fen)。
鋁電(dian)(dian)(dian)解(jie)(jie)電(dian)(dian)(dian)容的(de)(de)性能主要(yao)依(yi)賴其(qi)中介(jie)質(zhi)部分，即陽極金(jin)(jin)屬氧化(hua)膜(mo)部分。除(chu)受初始工(gong)藝(yi)的(de)(de)影(ying)響外，在(zai)工(gong)作過程中，電(dian)(dian)(dian)解(jie)(jie)液也會不(bu)斷(duan)修補并增(zeng)(zeng)厚(hou)該氧化(hua)膜(mo)，隨著(zhu)陽極金(jin)(jin)屬氧化(hua)膜(mo)的(de)(de)不(bu)斷(duan)增(zeng)(zeng)厚(hou)，鋁電(dian)(dian)(dian)解(jie)(jie)電(dian)(dian)(dian)容等效(xiao)電(dian)(dian)(dian)路模型(xing)中的(de)(de)電(dian)(dian)(dian)容值C會不(bu)斷(duan)下降，等效(xiao)串聯電(dian)(dian)(dian)阻ESR會不(bu)斷(duan)增(zeng)(zeng)大(da)，同時陰極反應產生的(de)(de)氫氣又加(jia)速了電(dian)(dian)(dian)解(jie)(jie)液的(de)(de)揮(hui)發，這些便是引起鋁電(dian)(dian)(dian)解(jie)(jie)電(dian)(dian)(dian)容退(tui)化(hua)的(de)(de)主要(yao)因素。
因而，雖然電(dian)解電(dian)容(rong)有(you)著其他類型的(de)電(dian)容(rong)無法替(ti)代的(de)優勢(shi)，但還是具(ju)有(you)內部損耗大(da)、靜電(dian)容(rong)量誤差(cha)大(da)、漏電(dian)流(liu)大(da)、高低溫特(te)性(xing)差(cha)等缺陷。故采用電(dian)解電(dian)容(rong)設計的(de)常(chang)規AC-DC電(dian)源模塊在高低溫特(te)性(xing)、可靠性(xing)、使用壽(shou)命等方面具(ju)有(you)明(ming)顯的(de)劣勢(shi)。
那么，如果AC-DC電(dian)源(yuan)設計中不使用(yong)電(dian)解電(dian)容，電(dian)源(yuan)產品將會怎樣(yang)呢？無電(dian)解電(dian)容的AC-DC電(dian)源(yuan)模塊是否可(ke)避免上(shang)述(shu)致(zhi)命缺陷？
日前，金升陽通(tong)過采用高壓陶瓷(ci)電(dian)容的(de)填谷(gu)電(dian)路設計替代并優(you)化電(dian)解(jie)(jie)電(dian)容的(de)基本功能，成(cheng)功設計出滿(man)足性能要求的(de)無(wu)電(dian)解(jie)(jie)電(dian)容AC-DC電(dian)源(yuan)模塊(kuai)LN系列，解(jie)(jie)決了AC-DC電(dian)源(yuan)因電(dian)解(jie)(jie)電(dian)容而帶來的(de)產品(pin)大體(ti)積、壽命短、高低(di)溫(wen)性能差等問題。
二、無電解電容產品的優勢
與電(dian)(dian)解(jie)電(dian)(dian)容(rong)(rong)(rong)相比，陶瓷電(dian)(dian)容(rong)(rong)(rong)具(ju)有極低(di)的(de)ESR和ESL，能降低(di)因(yin)寄生參(can)數而引起的(de)損壞風險；同時(shi)，因(yin)陶瓷電(dian)(dian)容(rong)(rong)(rong)的(de)電(dian)(dian)解(jie)質在高(gao)低(di)溫(wen)(wen)等極限條件下不易(yi)揮發、凝固，容(rong)(rong)(rong)量相對穩定，能長(chang)時(shi)間保持電(dian)(dian)容(rong)(rong)(rong)的(de)電(dian)(dian)氣特性，從而極大地提高(gao)了電(dian)(dian)源產品的(de)高(gao)低(di)溫(wen)(wen)性能和長(chang)期使用的(de)可靠性。
1）高效(xiao)、環保
LN系列采用填(tian)谷電(dian)路進行設計，利用高壓陶瓷(ci)電(dian)容(rong)完美替代鋁電(dian)解(jie)電(dian)容(rong)，增加了(le)整流(liu)管(guan)的導通角(jiao)，使輸(shu)入電(dian)流(liu)波(bo)形(xing)從(cong)尖峰脈沖變得更接近(jin)正弦波(bo)，從(cong)而大幅度提(ti)高電(dian)源的功率因素（如(ru)表1所示），提(ti)高電(dian)源的轉換效(xiao)率，更加利于(yu)環保節(jie)能，顯著降(jiang)低總諧(xie)波(bo)失真。如(ru)圖1所示：
以(yi)下所有表中舊方案為采(cai)(cai)用電(dian)解電(dian)容的產(chan)品，新方案為采(cai)(cai)用填谷電(dian)路無電(dian)解電(dian)容的新產(chan)品
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2）產品壽命的(de)提升(sheng)
電(dian)(dian)源(yuan)本身是一個功率器件，在正常工(gong)作時功率損耗通過熱(re)的(de)形式(shi)散(san)發(fa)到外部(bu)，其(qi)內(nei)(nei)部(bu)的(de)變壓(ya)器、開關器件、整流二極管等都是發(fa)熱(re)器件。除(chu)內(nei)(nei)部(bu)因素外，大(da)部(bu)分電(dian)(dian)源(yuan)需應用(yong)(yong)在較高的(de)環(huan)境溫度中，這些都會(hui)導致電(dian)(dian)解(jie)液的(de)揮(hui)發(fa)，降低電(dian)(dian)解(jie)電(dian)(dian)容的(de)使用(yong)(yong)壽命。
陶(tao)瓷電容(rong)(rong)采用特(te)性(xing)最穩(wen)定的陶(tao)瓷材料作(zuo)(zuo)為(wei)介質，特(te)別是一類(lei)陶(tao)瓷電容(rong)(rong)（NOP) 能實現-55℃~+125℃的工(gong)(gong)作(zuo)(zuo)環境溫度(du)(du)(du)，容(rong)(rong)量(liang)變(bian)(bian)化(hua)不超過±30ppm/℃。電容(rong)(rong)溫度(du)(du)(du)變(bian)(bian)化(hua)時，容(rong)(rong)值(zhi)很穩(wen)定，即具有(you)溫度(du)(du)(du)補償功能，適用于要求(qiu)容(rong)(rong)值(zhi)在溫度(du)(du)(du)變(bian)(bian)化(hua)范圍(wei)內穩(wen)定和高Q值(zhi)的線路以及(ji)各種諧振線路中；二(er)/三類(lei)陶(tao)瓷（X7R）實現-55℃~+125℃的工(gong)(gong)作(zuo)(zuo)溫度(du)(du)(du)范圍(wei)內，容(rong)(rong)量(liang)最大(da)的變(bian)(bian)化(hua)為(wei) ±15%。
從高(gao)壓陶(tao)瓷(ci)電(dian)容(rong)的(de)介質與(yu)鋁(lv)電(dian)解電(dian)容(rong)的(de)電(dian)解液介質本身(shen)的(de)特性(xing)可以(yi)看出，陶(tao)瓷(ci)電(dian)容(rong)能夠(gou)承受更(geng)嚴格的(de)環境要求，對(dui)電(dian)源產(chan)品(pin)的(de)壽命、可靠性(xing)的(de)設計都有著重要的(de)意義，能夠(gou)很大程度地提高(gao)電(dian)源產(chan)品(pin)的(de)使用(yong)壽命以(yi)及可靠性(xing)。
金升陽無電(dian)解(jie)(jie)(jie)電(dian)容LN系列通過采用填谷電(dian)路，利(li)用高(gao)壓陶(tao)瓷電(dian)容成功替代鋁電(dian)解(jie)(jie)(jie)電(dian)容，能夠有(you)效避免電(dian)解(jie)(jie)(jie)電(dian)容因(yin)內部電(dian)解(jie)(jie)(jie)液(ye)(ye)導致的(de)高(gao)低溫(wen)性能差問(wen)題；避免因(yin)電(dian)解(jie)(jie)(jie)液(ye)(ye)的(de)揮發導致電(dian)容容值(zhi)下降(jiang)、電(dian)源產品壽命降(jiang)低問(wen)題；甚(shen)至可以(yi)避免因(yin)電(dian)解(jie)(jie)(jie)液(ye)(ye)的(de)劇烈噴發或者(zhe)漏液(ye)(ye)引起(qi)的(de)安全問(wen)題。
3）穩定的高低溫(wen)特(te)性
目前，大多數常規(gui)電(dian)(dian)解(jie)電(dian)(dian)容(rong)的(de)額(e)定(ding)工(gong)作溫(wen)度(du)為105℃，但因(yin)電(dian)(dian)解(jie)電(dian)(dian)容(rong)在(zai)高(gao)溫(wen)條件(jian)下(xia)(xia)電(dian)(dian)解(jie)液易(yi)揮發，電(dian)(dian)源本身發熱較(jiao)大等原(yuan)因(yin)，常規(gui)采(cai)(cai)用電(dian)(dian)解(jie)電(dian)(dian)容(rong)的(de)AC-DC電(dian)(dian)源只能工(gong)作在(zai)70℃的(de)環(huan)境(jing)條件(jian)下(xia)(xia)。要提(ti)高(gao)電(dian)(dian)源的(de)工(gong)作環(huan)境(jing)溫(wen)度(du)，必須采(cai)(cai)用價格(ge)更昂貴、體積更大的(de)電(dian)(dian)解(jie)電(dian)(dian)容(rong)，或(huo)者以降額(e)的(de)方式實現高(gao)低溫(wen)條件(jian)下(xia)(xia)的(de)應(ying)用，下(xia)(xia)面以金升(sheng)陽常規(gui)AC-DC電(dian)(dian)源產品在(zai)高(gao)低溫(wen)環(huan)境(jing)下(xia)(xia)的(de)降額(e)要求如圖3：
金升陽LN系列能(neng)在成(cheng)本、體積變化不(bu)大的(de)(de)情(qing)況下(xia)(xia)實(shi)現高溫(wen)工作，能(neng)滿足-40℃到(dao)70℃條件下(xia)(xia)無任何降額要求，可應(ying)用在環境溫(wen)度較高/較低，且對電源(yuan)產品的(de)(de)可靠性、使(shi)用壽命(ming)較高的(de)(de)場合，如路燈控(kong)制、LED等(deng)行業。
4）高EMC特性(xing)
金升陽(yang)無電解電容LN系列(lie)產品，充分考慮到不同應(ying)用(yong)場合、不同的(de)設計要求，對(dui)產品的(de)EMC性能進行了全面的(de)升級(ji)優(you)化。在模塊內部通(tong)過(guo)PCB設計、采用(yong)多級(ji)EMC濾波等方式實現在無任何外圍防護(hu)器件的(de)情況下EMI滿足(zu)CLSS B，防浪涌(yong)能力(li)達4級(ji)。
三、總(zong)結(jie)
金升陽(yang)無電(dian)解電(dian)容AC-DC電(dian)源模(mo)塊LN系列的成功(gong)(gong)開發(fa)證明(ming)AC-DC電(dian)源設計中也可(ke)(ke)不(bu)使用(yong)電(dian)解電(dian)容。通過(guo)采用(yong)高(gao)壓(ya)陶瓷電(dian)容的填谷電(dian)路設計替代并優化電(dian)解電(dian)容的基本功(gong)(gong)能，能夠完美解決電(dian)源模(mo)塊因電(dian)解電(dian)容本身固有缺陷而產(chan)生的高(gao)低溫性能差、可(ke)(ke)靠(kao)性差、使用(yong)壽命(ming)短等問題。
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