直(zhi)流濾波電(dian)(dian)容器在開關(guan)(guan)電(dian)(dian)源中起著(zhu)非(fei)常重要(yao)的作(zuo)用, 如何正確選擇(ze)直(zhi)流濾波電(dian)(dian)容器, 特別是輸出濾波電(dian)(dian)容器的選擇(ze), 是每個工程技術人員都(dou)非(fei)常關(guan)(guan)心的問題(ti)。

正確選擇直流濾波電容器

(1) 應根據電(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)(lu)要求選(xuan)擇(ze)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)容(rong)(rong)(rong)(rong)器(qi)(qi)的(de)類(lei)型。對(dui)于低頻(pin)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)(lu)和(he)直流(liu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)(lu), 一般采用(yong)(yong)紙張(zhang)介(jie)(jie)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)容(rong)(rong)(rong)(rong)器(qi)(qi), 可(ke)(ke)選(xuan)用(yong)(yong)低頻(pin)瓷(ci)(ci)介(jie)(jie)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)容(rong)(rong)(rong)(rong)器(qi)(qi)。在高(gao)(gao)(gao)(gao)頻(pin)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)(lu)中(zhong)(zhong), 當電(dian)(dian)(dian)(dian)(dian)(dian)(dian)氣(qi)性能要求高(gao)(gao)(gao)(gao)時(shi), 云(yun)母電(dian)(dian)(dian)(dian)(dian)(dian)(dian)容(rong)(rong)(rong)(rong)器(qi)(qi)、高(gao)(gao)(gao)(gao)頻(pin)陶(tao)瓷(ci)(ci)介(jie)(jie)質(zhi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)容(rong)(rong)(rong)(rong)器(qi)(qi)或陶(tao)瓷(ci)(ci)介(jie)(jie)質(zhi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)容(rong)(rong)(rong)(rong)器(qi)(qi)均可(ke)(ke)選(xuan)用(yong)(yong)。在中(zhong)(zhong)頻(pin)和(he)低頻(pin)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)(lu)中(zhong)(zhong), 可(ke)(ke)以使用(yong)(yong)塑料薄膜(mo)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)容(rong)(rong)(rong)(rong)器(qi)(qi)。在電(dian)(dian)(dian)(dian)(dian)(dian)(dian)力濾波器(qi)(qi)和(he)解耦電(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)(lu)中(zhong)(zhong), 常用(yong)(yong)的(de)是(shi)鋁(lv)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)解電(dian)(dian)(dian)(dian)(dian)(dian)(dian)容(rong)(rong)(rong)(rong)器(qi)(qi)。對(dui)于需要高(gao)(gao)(gao)(gao)可(ke)(ke)靠性和(he)高(gao)(gao)(gao)(gao)穩定(ding)性的(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)(lu), 應選(xuan)擇(ze)云(yun)母電(dian)(dian)(dian)(dian)(dian)(dian)(dian)容(rong)(rong)(rong)(rong)器(qi)(qi)、薄膜(mo)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)容(rong)(rong)(rong)(rong)器(qi)(qi)或鉭電(dian)(dian)(dian)(dian)(dian)(dian)(dian)解電(dian)(dian)(dian)(dian)(dian)(dian)(dian)容(rong)(rong)(rong)(rong)器(qi)(qi)。對(dui)于高(gao)(gao)(gao)(gao)壓電(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)(lu), 應選(xuan)擇(ze)高(gao)(gao)(gao)(gao)壓瓷(ci)(ci)介(jie)(jie)質(zhi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)容(rong)(rong)(rong)(rong)器(qi)(qi)或其(qi)它類(lei)型的(de)高(gao)(gao)(gao)(gao)壓電(dian)(dian)(dian)(dian)(dian)(dian)(dian)容(rong)(rong)(rong)(rong)器(qi)(qi)。對(dui)于調(diao)(diao)諧(xie)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)(lu), 應選(xuan)擇(ze)可(ke)(ke)變和(he)微調(diao)(diao)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)容(rong)(rong)(rong)(rong)器(qi)(qi)

(2) 合理(li)確定電(dian)(dian)容(rong)(rong)(rong)器的(de)(de)電(dian)(dian)容(rong)(rong)(rong)和允(yun)許偏差(cha)。在(zai)低(di)頻耦合和解耦電(dian)(dian)路中(zhong), 電(dian)(dian)容(rong)(rong)(rong)器的(de)(de)電(dian)(dian)容(rong)(rong)(rong)要(yao)求(qiu)一般不太(tai)嚴格, 只(zhi)要(yao)計(ji)算(suan)值稍大就可以選擇(ze)(ze)。在(zai)時序電(dian)(dian)路、振蕩電(dian)(dian)路和音調(diao)控制電(dian)(dian)路中(zhong), 電(dian)(dian)容(rong)(rong)(rong)器的(de)(de)電(dian)(dian)容(rong)(rong)(rong)要(yao)求(qiu)更嚴格, 所(suo)以選擇(ze)(ze)電(dian)(dian)容(rong)(rong)(rong)的(de)(de)標稱值應(ying)(ying)盡可能(neng)接近(jin)計(ji)算(suan)出(chu)的(de)(de)電(dian)(dian)容(rong)(rong)(rong)器值,應(ying)(ying)盡可能(neng)選擇(ze)(ze)高精(jing)度的(de)(de)電(dian)(dian)容(rong)(rong)(rong)器。在(zai)某些特殊(shu)電(dian)(dian)路中(zhong), 電(dian)(dian)容(rong)(rong)(rong)器的(de)(de)電(dian)(dian)容(rong)(rong)(rong)要(yao)求(qiu)非常精(jing)確, 在(zai)0中(zhong)應(ying)(ying)使用(yong)允(yun)許偏差(cha)。1% ~ 05% 高精(jing)度電(dian)(dian)容(rong)(rong)(rong)器在(zai)范圍內。

優先選用具有大絕(jue)緣電阻、小介質損(sun)耗和小泄(xie)漏電流(liu)的直流(liu)濾波電容器。