電磁灶常見調試功率方法

一、間隙加熱法

間(jian)隙施加(jia)激勵脈(mo)沖，使電(dian)(dian)磁(ci)灶斷(duan)續加(jia)熱(re)，控制斷(duan)續加(jia)熱(re)時間(jian)間(jian)隔(ge)來調節電(dian)(dian)磁(ci)灶的(de)功(gong)率。該方式(shi)電(dian)(dian)路簡單(dan)，但是(shi)有通斷(duan)時的(de)電(dian)(dian)磁(ci)噪聲出現并且對供電(dian)(dian)電(dian)(dian)源有電(dian)(dian)流沖擊(ji)。采(cai)用該調功(gong)方式(shi)要注(zhu)意激勵脈(mo)沖的(de)關(guan)(guan)斷(duan)必須在電(dian)(dian)流過零(ling)時刻，否則關(guan)(guan)斷(duan)時鍋底的(de)電(dian)(dian)磁(ci)噪音較(jiao)大。

二、脈沖功率輸出變壓器初級抽頭切換法

可通過控制電路分別接通三只交流接觸器的常開觸點J1-1、J2-1、J3-1，來接通脈沖功率輸出變壓器初級(ji)抽頭，以(yi)分別獲(huo)得大、中、小、三擋功率(lv)。這種調功方(fang)式(shi)因為有接觸器的(de)存(cun)在，機芯體積較大，但是在大、中、小三擋功率(lv)時都(dou)可以(yi)用頻率(lv)跟蹤的(de)方(fang)法使功率(lv)管工作在零電(dian)壓(ya)開(kai)關(guan)和零電(dian)流(liu)開(kai)關(guan)狀態。在所有調功方(fang)式(shi)中該方(fang)式(shi)的(de)功率(lv)管的(de)溫升(sheng)最低，電(dian)磁灶的(de)熱效率(lv)高達95%以(yi)上。

接(jie)觸器的接(jie)通與釋放必須先關(guan)斷激(ji)勵脈(mo)沖，使之在功率輸出級無電流的狀態(tai)下進行(xing)切換。

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三、移相調脈寬法

電路中，若變壓(ya)器沒(mei)有抽頭，僅起到感(gan)應線圈與主電源的(de)(de)(de)隔(ge)離(li)、與負載的(de)(de)(de)匹配作用(yong)。T1、T2為左邊(bian)橋臂(bei)，T3、T4為右(you)邊(bian)橋臂(bei)。T1、T2的(de)(de)(de)激(ji)(ji)勵脈沖(chong)反(fan)相并留有足夠(gou)的(de)(de)(de)死區(qu)時(shi)間，保證T1、T2不致(zhi)產(chan)生(sheng)共態導(dao)通(tong)。同(tong)理，T3、T4的(de)(de)(de)激(ji)(ji)勵脈沖(chong)反(fan)相并且也留有足夠(gou)的(de)(de)(de)死區(qu)時(shi)間。當左右(you)橋臂(bei)的(de)(de)(de)激(ji)(ji)勵脈沖(chong)相位(wei)差從180°~0°變化時(shi)，電磁灶(zao)的(de)(de)(de)功(gong)(gong)率(lv)從最(zui)(zui)大(da)至(zhi)最(zui)(zui)小連續平滑地變化，半邊(bian)橋臂(bei)的(de)(de)(de)功(gong)(gong)率(lv)管(guan)實現零電壓(ya)開(kai)關；另(ling)外半邊(bian)橋臂(bei)的(de)(de)(de)功(gong)(gong)率(lv)管(guan)實現零電流開(kai)關。實際使(shi)用(yong)移(yi)相調脈寬(kuan)法時(shi)，因省去了補(bu)償電感(gan)，當電磁灶(zao)功(gong)(gong)率(lv)較小時(shi)超前橋臂(bei)的(de)(de)(de)零電壓(ya)開(kai)關將(jiang)會失準，因此在小功(gong)(gong)率(lv)時(shi)宜改用(yong)間隙(xi)加熱的(de)(de)(de)方法來(lai)調節功(gong)(gong)率(lv)。

移相調脈寬法(fa)的缺點是IGBT管(guan)(guan)子中(zhong)(zhong)的續流二極(ji)管(guan)(guan)中(zhong)(zhong)有(you)較大(da)的電流通過，功率管(guan)(guan)的工作狀態不如上述變壓器抽頭(tou)法(fa)來得(de)好(hao)，其優點是可連(lian)續調節功率，省去(qu)了三(san)只交流接(jie)觸器。

四、改變整流電壓法

三相(xiang)整(zheng)(zheng)流(liu)模塊(kuai)改用可(ke)控整(zheng)(zheng)流(liu)模塊(kuai)，用0-10V的(de)控制電(dian)(dian)(dian)壓(ya)(ya)改變可(ke)控整(zheng)(zheng)流(liu)模塊(kuai)整(zheng)(zheng)流(liu)后的(de)直(zhi)流(liu)輸(shu)(shu)出(chu)電(dian)(dian)(dian)壓(ya)(ya)來(lai)改變電(dian)(dian)(dian)磁灶的(de)輸(shu)(shu)出(chu)功(gong)(gong)(gong)率。在額定(ding)輸(shu)(shu)入電(dian)(dian)(dian)壓(ya)(ya)下(xia)(xia)，整(zheng)(zheng)流(liu)模塊(kuai)全導通，獲(huo)得額定(ding)最大功(gong)(gong)(gong)率，在非額定(ding)最大功(gong)(gong)(gong)率下(xia)(xia)由于整(zheng)(zheng)流(liu)輸(shu)(shu)出(chu)的(de)直(zhi)流(liu)電(dian)(dian)(dian)壓(ya)(ya)下(xia)(xia)降(jiang)，功(gong)(gong)(gong)率呈現出(chu)與電(dian)(dian)(dian)壓(ya)(ya)的(de)平方(fang)關系(xi)下(xia)(xia)降(jiang)。該(gai)調功(gong)(gong)(gong)方(fang)式的(de)優點是電(dian)(dian)(dian)路(lu)簡單(dan)，可(ke)連續調功(gong)(gong)(gong)，在整(zheng)(zheng)個調功(gong)(gong)(gong)范圍內均(jun)可(ke)實現頻率跟蹤。該(gai)電(dian)(dian)(dian)路(lu)缺點是調功(gong)(gong)(gong)時可(ke)控整(zheng)(zheng)流(liu)模塊(kuai)沒(mei)有全導通，有斬波(bo)缺口，對(dui)電(dian)(dian)(dian)磁兼容性(xing)指(zhi)標影響較大。要使電(dian)(dian)(dian)磁兼容性(xing)指(zhi)標過關，對(dui)電(dian)(dian)(dian)源濾波(bo)器和(he)整(zheng)(zheng)流(liu)濾波(bo)電(dian)(dian)(dian)路(lu)要求較高(gao)，該(gai)部分的(de)元件數(shu)相(xiang)對(dui)較多，整(zheng)(zheng)機(ji)體積和(he)成(cheng)本增加(jia)。

五、調頻法

在(zai)(zai)最大功(gong)(gong)(gong)率時使電路(lu)工作(zuo)在(zai)(zai)近諧振狀(zhuang)態(tai)下(xia)(xia)，提高激勵脈沖頻率，電路(lu)工作(zuo)在(zai)(zai)失(shi)諧狀(zhuang)態(tai)下(xia)(xia)，功(gong)(gong)(gong)率減(jian)小。該方法(fa)(fa)的(de)優(you)點是電路(lu)簡單，但是當電磁灶輸出功(gong)(gong)(gong)率較(jiao)大時若發(fa)生調(diao)功(gong)(gong)(gong)，電流相(xiang)位滯(zhi)后電壓相(xiang)位較(jiao)大，在(zai)(zai)較(jiao)大電流的(de)狀(zhuang)態(tai)下(xia)(xia)關斷，功(gong)(gong)(gong)率管管耗(hao)較(jiao)大，這樣，即使散(san)熱器上的(de)溫升并(bing)沒有明顯升高，也(ye)有可(ke)能管芯(xin)已過熱而(er)損壞ICBT功(gong)(gong)(gong)率模(mo)塊，因此在(zai)(zai)8kW以上的(de)功(gong)(gong)(gong)率時不宜采用該方法(fa)(fa)調(diao)功(gong)(gong)(gong)。

六、變壓器初級抽頭切換、調頻、調壓法

通過變壓器初級(ji)抽頭的切(qie)換(huan)來獲得(de)大(da)、中(zhong)、小(xiao)(xiao)三(san)擋(dang)(dang)(dang)功(gong)(gong)(gong)(gong)率(lv)(lv)(lv)，由于脈(mo)(mo)沖功(gong)(gong)(gong)(gong)率(lv)(lv)(lv)輸出(chu)變壓(ya)器的使用，使得(de)功(gong)(gong)(gong)(gong)率(lv)(lv)(lv)輸出(chu)級(ji)與負載(zai)匹(pi)配良好，功(gong)(gong)(gong)(gong)率(lv)(lv)(lv)級(ji)能工(gong)(gong)作(zuo)在(zai)最佳(jia)狀態(tai)(tai)。在(zai)大(da)、中(zhong)、小(xiao)(xiao)三(san)擋(dang)(dang)(dang)功(gong)(gong)(gong)(gong)率(lv)(lv)(lv)處用頻(pin)(pin) 率(lv)(lv)(lv)跟蹤的方法(fa)使功(gong)(gong)(gong)(gong)率(lv)(lv)(lv)管(guan)工(gong)(gong)作(zuo)在(zai)零(ling)電(dian)壓(ya)開關(guan)(guan)(guan)和零(ling)電(dian)流(liu)開關(guan)(guan)(guan)狀態(tai)(tai)下(xia)。在(zai)小(xiao)(xiao)擋(dang)(dang)(dang)到(dao)中(zhong)擋(dang)(dang)(dang)、中(zhong)擋(dang)(dang)(dang)到(dao)大(da)擋(dang)(dang)(dang)調(diao)(diao)(diao)功(gong)(gong)(gong)(gong)范(fan)圍(wei)內再用微調(diao)(diao)(diao)激勵脈(mo)(mo)沖頻(pin)(pin)率(lv)(lv)(lv)的方法(fa)來連(lian)續調(diao)(diao)(diao)節功(gong)(gong)(gong)(gong)率(lv)(lv)(lv)，此時功(gong)(gong)(gong)(gong)率(lv)(lv)(lv)管(guan)工(gong)(gong)作(zuo)在(zai)零(ling)電(dian)壓(ya)開關(guan)(guan)(guan)和 零(ling)電(dian)流(liu)開通，近(jin)似零(ling)電(dian)流(liu)關(guan)(guan)(guan)斷(duan)狀態(tai)(tai)下(xia)。在(zai)小(xiao)(xiao)擋(dang)(dang)(dang)到(dao)零(ling)功(gong)(gong)(gong)(gong)率(lv)(lv)(lv)范(fan)圍(wei)內用調(diao)(diao)(diao)頻(pin)(pin)的方法(fa)會破壞功(gong)(gong)(gong)(gong)率(lv)(lv)(lv)管(guan)零(ling)電(dian)壓(ya)開關(guan)(guan)(guan)的狀態(tai)(tai)，則(ze)采用調(diao)(diao)(diao)節輸出(chu)整流(liu)電(dian)壓(ya)的方法(fa)來調(diao)(diao)(diao)節功(gong)(gong)(gong)(gong)率(lv)(lv)(lv)。

這種調功方式相對較(jiao)為復(fu)雜(za)，成本也高，其突出優點是(shi)調功范圍大、功率輸出級(ji)與負載匹(pi)配良好(hao)、電磁灶在8kW功率時散熱器(qi)溫(wen)升(sheng)不超過6℃（在25℃的環(huan)境溫(wen)度(du)下(xia)測(ce)試）。