中頻爐電源對使用的(de)影響

中(zhong)頻爐電(dian)(dian)(dian)(dian)源整流(liu)電(dian)(dian)(dian)(dian)路(lu)的(de)負(fu)載(zai)(zai)是逆變器(qi)，逆變器(qi)輸出有功(gong)功(gong)率是整流(liu)電(dian)(dian)(dian)(dian)路(lu)提供(gong)的(de)，要求整流(liu)電(dian)(dian)(dian)(dian)路(lu)的(de)直(zhi)流(liu)輸出電(dian)(dian)(dian)(dian)壓(ya)在(zai)規定的(de)范圍內能(neng)連續平滑可調。 中(zhong)頻爐電(dian)(dian)(dian)(dian)源的(de)負(fu)載(zai)(zai)變化(hua)很大，整流(liu)的(de)電(dian)(dian)(dian)(dian)路(lu)應該自動(dong)的(de)***輸出的(de)電(dian)(dian)(dian)(dian)壓(ya)。通常情況(kuang)下是會采用在(zai)負(fu)載(zai)(zai)端取出電(dian)(dian)(dian)(dian)流(liu)、電(dian)(dian)(dian)(dian)壓(ya)的(de)信(xin)號來(lai)改變整流(liu)的(de)移(yi)相控制角(jiao)，從而完成截流(liu)、截壓(ya)。

中頻爐電(dian)(dian)(dian)(dian)源要求整流(liu)(liu)(liu)電(dian)(dian)(dian)(dian)路應對系(xi)統進行過電(dian)(dian)(dian)(dian)壓和過電(dian)(dian)(dian)(dian)流(liu)(liu)(liu)保(bao)護，采用(yong)移(yi)相控制角等(deng)于150度來(lai)使(shi)直(zhi)流(liu)(liu)(liu)輸出負壓形成有(you)源逆變(bian)。直(zhi)流(liu)(liu)(liu)電(dian)(dian)(dian)(dian)抗器是有(you)源逆變(bian)的(de)(de)一個重要條件，大部分中頻電(dian)(dian)(dian)(dian)源采用(yong)三相全控橋式整流(liu)(liu)(liu)電(dian)(dian)(dian)(dian)路。因為它(ta)的(de)(de)輸出電(dian)(dian)(dian)(dian)壓調節(jie)范(fan)圍大而(er)移(yi)相控制角的(de)(de)變(bian)化范(fan)圍小，有(you)利于系(xi)統的(de)(de)自動調節(jie)，它(ta)輸出電(dian)(dian)(dian)(dian)壓的(de)(de)脈動頻率較高可(ke)以減輕直(zhi)流(liu)(liu)(liu)濾波環節(jie)的(de)(de)負擔。

中頻(pin)爐電源對整流電路(lu)還有(you)(you)一個要求是：當逆變(bian)器運行失敗(bai)時，能(neng)把儲(chu)存在(zai)電抗(kang)器中的能(neng)量通過整流電路(lu)返回到工頻(pin)電網，使逆變(bian)得到保護，即有(you)(you)源逆變(bian)。

如何(he)保護中頻爐的晶閘管正常運行

因中頻(pin)(pin)熔(rong)(rong)煉爐系統中晶閘(zha)管的(de)過壓(ya)、過電(dian)(dian)流(liu)耐力差，必須采取適當的(de)保護(hu)措施(shi)。在中頻(pin)(pin)熔(rong)(rong)煉爐的(de)系統中，晶閘(zha)管是組成(cheng)全(quan)控(kong)橋整(zheng)流(liu)電(dian)(dian)路(lu)和逆變系統電(dian)(dian)路(lu)的(de)主(zhu)要器(qi)件。對晶閘(zha)管的(de)保護(hu)應(ying)用過電(dian)(dian)壓(ya)及過電(dian)(dian)流(liu)保護(hu)電(dian)(dian)路(lu)，同時(shi)還要抑制電(dian)(dian)壓(ya)和電(dian)(dian)流(liu)的(de)上升率。

但由于晶(jing)閘(zha)管元(yuan)件的擊穿電(dian)(dian)壓(ya)較接近于運(yun)行電(dian)(dian)壓(ya)，熱時(shi)間(jian)常數小，因此過(guo)(guo)(guo)(guo)(guo)電(dian)(dian)壓(ya)、過(guo)(guo)(guo)(guo)(guo)電(dian)(dian)流(liu)能力差，短(duan)時(shi)間(jian)的過(guo)(guo)(guo)(guo)(guo)電(dian)(dian)流(liu)、過(guo)(guo)(guo)(guo)(guo)電(dian)(dian)壓(ya)都可(ke)能造成元(yuan)件的損壞。所以(yi)在晶(jing)閘(zha)管裝置中，不能只靠(kao)合理選擇元(yuan)件，還采取適當的保護措施。對晶(jing)閘(zha)管的保護應當包括過(guo)(guo)(guo)(guo)(guo)電(dian)(dian)壓(ya)保護、過(guo)(guo)(guo)(guo)(guo)電(dian)(dian)流(liu)保護，還有對電(dian)(dian)壓(ya)、電(dian)(dian)流(liu)上(shang)升率的限制。