逆(ni)变器场效应管

主要(yao)用(yong)处逆(ni)变(bian)(bian)器是把直流(liu)电(dian)(dian)(dian)(dian)(dian)能（电(dian)(dian)(dian)(dian)(dian)池、蓄电(dian)(dian)(dian)(dian)(dian)瓶）转(zhuan)变(bian)(bian)成交(jiao)流(liu)电(dian)(dian)(dian)(dian)(dian)（普通为220v50HZ正弦或方波(bo)）。浅显的讲，逆(ni)变(bian)(bian)器是一种将直流(liu)电(dian)(dian)(dian)(dian)(dian)（DC）转(zhuan)化(hua)为交(jiao)流(liu)电(dian)(dian)(dian)(dian)(dian)（AC）的安装。它由逆(ni)变(bian)(bian)桥、控制逻辑和滤波(bo)电(dian)(dian)(dian)(dian)(dian)路组成。普遍适用(yong)于(yu)空调、家庭(ting)影院(yuan)、电(dian)(dian)(dian)(dian)(dian)动砂轮、电(dian)(dian)(dian)(dian)(dian)开工(gong)具、缝纫机(ji)(ji)(ji)、DVD、VCD、电(dian)(dian)(dian)(dian)(dian)脑(nao)、电(dian)(dian)(dian)(dian)(dian)视、洗衣机(ji)(ji)(ji)、抽油烟机(ji)(ji)(ji)、冰箱，录像(xiang)机(ji)(ji)(ji)、按摩器、风扇、照明等 。

逆(ni)变器原理

逆变(bian)(bian)器就是一种(zhong)将低(di)压(12或(huo)24伏(fu)(fu)或(huo)48伏(fu)(fu))直流电(dian)(dian)(dian)转(zhuan)变(bian)(bian)为220伏(fu)(fu)交流电(dian)(dian)(dian)的(de)(de)(de)电(dian)(dian)(dian)子设备(bei)。由于我(wo)(wo)(wo)们通(tong)常是将220伏(fu)(fu)交流电(dian)(dian)(dian)整流变(bian)(bian)成(cheng)直流电(dian)(dian)(dian)来(lai)运用，而逆变(bian)(bian)器的(de)(de)(de)作用与此相反，因而而得名。我(wo)(wo)(wo)们处在(zai)一个“挪动”的(de)(de)(de)时(shi)期，挪动办公，挪动通(tong)讯，挪动休闲和文娱。在(zai)挪动的(de)(de)(de)状态中，人们不(bu)但需(xu)求(qiu)由电(dian)(dian)(dian)池或(huo)电(dian)(dian)(dian)瓶(ping)供(gong)应的(de)(de)(de)低(di)压直流电(dian)(dian)(dian)，同时(shi)更需(xu)求(qiu)我(wo)(wo)(wo)们在(zai)日(ri)常环境中不(bu)可(ke)或(huo)缺的(de)(de)(de)220伏(fu)(fu)交流电(dian)(dian)(dian)，逆变(bian)(bian)器就能够满(man)足我(wo)(wo)(wo)们的(de)(de)(de)这种(zhong)需(xu)求(qiu)。

逆变器(qi)的主要(yao)参(can)数指标

1.额(e)定(ding)功率：3KW，过载能力为(wei)：150%

2.输入电压范围：DC300~600V

3.额定输出电压(ya)：AC220V/50Hz

4.额(e)定(ding)功(gong)率(lv)因数：0.99

5.额定转换效率：94%

6.隔离方(fang)式(shi)：无变压器(qi)，非隔离方(fang)式(shi)

7.保(bao)护(hu)功能：过(guo)压、欠压、过(guo)流、短(duan)路、过(guo)热保(bao)护(hu)

详解逆变器电路(lu)工作原(yuan)理

这里引(yin)见(jian)的逆变(bian)器(qi)（见(jian)图1）主要由MOS场(chang)效应(ying)(ying)管，普通电(dian)(dian)源变(bian)压器(qi)构成。其输出(chu)功(gong)率(lv)取决(jue)于MOS场(chang)效应(ying)(ying)管和电(dian)(dian)源变(bian)压器(qi)的功(gong)率(lv)，免除(chu)了烦琐的变(bian)压器(qi)绕制，合适电(dian)(dian)子喜好者业余制造中(zhong)采用。下面引(yin)见(jian)该逆变(bian)器(qi)的工作原理及(ji)制造过程。

这里采(cai)用六反相器CD4069构成(cheng)方波信(xin)号发作(zuo)器。电(dian)路中R1是补偿电(dian)阻，用于改善由于电(dian)源电(dian)压的(de)变化而惹起的(de)振(zhen)荡频率不稳。电(dian)路的(de)振(zhen)荡是经过(guo)电(dian)容C1充放电(dian)完成(cheng)的(de)。

其振荡频率为f=1/2.2RC.

图示电(dian)路的最大(da)频率(lv)为：fmax=1/2.2×3.3×103×2.2×10-6=62.6Hz；

最小(xiao)频率fmin=1/2.2×4.3×103×2.2×10-6=48.0Hz；

由(you)于元件的误差(cha)，实践值(zhi)会略有差(cha)别(bie)。其它多余的反相器，输入端接(jie)地防止影响其它电路。

由于(yu)方波信号发作器输出的振(zhen)荡(dang)信号电压最大振(zhen)幅为0~5V，为充(chong)沛驱动电源(yuan)开关电路(lu)，这里用TR1、TR2将振(zhen)荡(dang)信号电压放大至0~12V.如图所(suo)示。

MOS场效应管(guan)电(dian)源开关(guan)电(dian)路

下面简述一下用C-MOS场(chang)(chang)(chang)(chang)效(xiao)(xiao)应(ying)(ying)(ying)管(guan)（加(jia)强型(xing)MOS场(chang)(chang)(chang)(chang)效(xiao)(xiao)应(ying)(ying)(ying)管(guan)）组成(cheng)(cheng)的应(ying)(ying)(ying)用电(dian)(dian)(dian)路(lu)的工作(zuo)过(guo)程（见图4）。电(dian)(dian)(dian)路(lu)将一个加(jia)强型(xing)P沟(gou)(gou)道(dao)(dao)MOS场(chang)(chang)(chang)(chang)效(xiao)(xiao)应(ying)(ying)(ying)管(guan)和(he)一个加(jia)强型(xing)N沟(gou)(gou)道(dao)(dao)MOS场(chang)(chang)(chang)(chang)效(xiao)(xiao)应(ying)(ying)(ying)管(guan)组合在(zai)一同运用。当输(shu)入端(duan)为(wei)(wei)低电(dian)(dian)(dian)平常，P沟(gou)(gou)道(dao)(dao)MOS场(chang)(chang)(chang)(chang)效(xiao)(xiao)应(ying)(ying)(ying)管(guan)导通，输(shu)出(chu)端(duan)与电(dian)(dian)(dian)源正极(ji)接通。当输(shu)入端(duan)为(wei)(wei)高电(dian)(dian)(dian)平常，N沟(gou)(gou)道(dao)(dao)MOS场(chang)(chang)(chang)(chang)效(xiao)(xiao)应(ying)(ying)(ying)管(guan)导通，输(shu)出(chu)端(duan)与电(dian)(dian)(dian)源地(di)接通。在(zai)该(gai)电(dian)(dian)(dian)路(lu)中(zhong)，P沟(gou)(gou)道(dao)(dao)MOS场(chang)(chang)(chang)(chang)效(xiao)(xiao)应(ying)(ying)(ying)管(guan)和(he)N沟(gou)(gou)道(dao)(dao)MOS场(chang)(chang)(chang)(chang)效(xiao)(xiao)应(ying)(ying)(ying)管(guan)总是在(zai)相反的状态下工作(zuo)，其(qi)相位输(shu)入端(duan)和(he)输(shu)出(chu)端(duan)相反。经过(guo)这种(zhong)工作(zuo)方式我们能够(gou)取得较大的电(dian)(dian)(dian)流(liu)输(shu)出(chu)。同时由(you)于(yu)漏(lou)电(dian)(dian)(dian)流(liu)的影响(xiang)，使得栅压在(zai)还(hai)没有(you)(you)到0V，通常在(zai)栅极(ji)电(dian)(dian)(dian)压小(xiao)于(yu)1到2V时，MOS场(chang)(chang)(chang)(chang)效(xiao)(xiao)应(ying)(ying)(ying)管(guan)既(ji)被关断。不(bu)同场(chang)(chang)(chang)(chang)效(xiao)(xiao)应(ying)(ying)(ying)管(guan)其(qi)关断电(dian)(dian)(dian)压略有(you)(you)不(bu)同。也正由(you)于(yu)如此，使得该(gai)电(dian)(dian)(dian)路(lu)不(bu)会由(you)于(yu)两管(guan)同时导通而形(xing)成(cheng)(cheng)电(dian)(dian)(dian)源短路(lu)。

点击(ji)放大图(tu)片(pian)由以上(shang)剖析(xi)我们能(neng)够画出原理图(tu)中(zhong)MOS场效应管(guan)电路局(ju)部的(de)(de)工作(zuo)(zuo)过程(cheng)（见图(tu)5）。工作(zuo)(zuo)原理同前所述。这(zhei)种低(di)电压(ya)(ya)(ya)(ya)、大电流(liu)、频(pin)率(lv)为50Hz的(de)(de)交变(bian)(bian)信号经(jing)过变(bian)(bian)压(ya)(ya)(ya)(ya)器(qi)的(de)(de)低(di)压(ya)(ya)(ya)(ya)绕组时，会在变(bian)(bian)压(ya)(ya)(ya)(ya)器(qi)的(de)(de)高(gao)(gao)压(ya)(ya)(ya)(ya)侧感应出高(gao)(gao)压(ya)(ya)(ya)(ya)交流(liu)电压(ya)(ya)(ya)(ya)，完成直流(liu)到(dao)交流(liu)的(de)(de)转换。这(zhei)里需求留意的(de)(de)是，在某些(xie)状况下(xia)，如振(zhen)荡局(ju)部中(zhong)止工作(zuo)(zuo)时，变(bian)(bian)压(ya)(ya)(ya)(ya)器(qi)的(de)(de)低(di)压(ya)(ya)(ya)(ya)侧有(you)(you)时会有(you)(you)很大的(de)(de)电流(liu)经(jing)过，所以该电路的(de)(de)保险丝(si)不能(neng)省略(lve)或短接(jie)。

制造要点

电(dian)(dian)(dian)路板见图(tu)6。所用(yong)元器件可(ke)参(can)考(kao)图(tu)7。逆(ni)变器用(yong)的(de)变压(ya)器采用(yong)次(ci)级为(wei)12V、电(dian)(dian)(dian)流(liu)为(wei)10A、初级电(dian)(dian)(dian)压(ya)为(wei)220V的(de)废品电(dian)(dian)(dian)源(yuan)变压(ya)器。P沟(gou)道(dao)MOS场(chang)效应管(guan)（2SJ471）最(zui)大(da)漏(lou)极(ji)电(dian)(dian)(dian)流(liu)为(wei)30A，在场(chang)效应管(guan)导通时(shi)，漏(lou)-源(yuan)极(ji)间电(dian)(dian)(dian)阻为(wei)25毫欧。此时(shi)假如(ru)经(jing)过(guo)10A电(dian)(dian)(dian)流(liu)时(shi)会有2.5W的(de)功(gong)率耗费。N沟(gou)道(dao)MOS场(chang)效应管(guan)（2SK2956）最(zui)大(da)漏(lou)极(ji)电(dian)(dian)(dian)流(liu)为(wei)50A，场(chang)效应管(guan)导通时(shi)，漏(lou)-源(yuan)极(ji)间电(dian)(dian)(dian)阻为(wei)7毫欧，此时(shi)假如(ru)经(jing)过(guo)10A电(dian)(dian)(dian)流(liu)时(shi)耗费的(de)功(gong)率为(wei)0.7W.由此我们也(ye)可(ke)知在同(tong)样的(de)工(gong)作电(dian)(dian)(dian)流(liu)状(zhuang)况下，2SJ471的(de)发热(re)量约为(wei)2SK2956的(de)4倍。所以在思索散热(re)器时(shi)应留意这点。图(tu)8展现本文(wen)引见的(de)逆(ni)变器场(chang)效应管(guan)在散热(re)器（100mm×100mm×17mm）上的(de)位置散布和接法。虽然场(chang)效应管(guan)工(gong)作于开关状(zhuang)态时(shi)发热(re)量不会很(hen)大(da)，出(chu)于安全思考(kao)这里选用(yong)的(de)散热(re)器稍(shao)偏大(da)。

逆变器电路板

逆变器的性能测试

测试电(dian)(dian)(dian)(dian)路见图9.这里(li)测试用(yong)(yong)的(de)(de)输(shu)(shu)入电(dian)(dian)(dian)(dian)源(yuan)采用(yong)(yong)内(nei)阻低、放电(dian)(dian)(dian)(dian)电(dian)(dian)(dian)(dian)流(liu)大（普通(tong)大于(yu)100A）的(de)(de)12V汽车电(dian)(dian)(dian)(dian)瓶(ping)，可(ke)为(wei)电(dian)(dian)(dian)(dian)路提供充足(zu)的(de)(de)输(shu)(shu)入功(gong)率。测试用(yong)(yong)负载为(wei)普通(tong)的(de)(de)电(dian)(dian)(dian)(dian)灯泡。测试的(de)(de)办法是(shi)(shi)经(jing)过(guo)改动负载大小，并(bing)丈量此时的(de)(de)输(shu)(shu)入电(dian)(dian)(dian)(dian)流(liu)、电(dian)(dian)(dian)(dian)压(ya)以及输(shu)(shu)出(chu)(chu)电(dian)(dian)(dian)(dian)压(ya)。输(shu)(shu)出(chu)(chu)电(dian)(dian)(dian)(dian)压(ya)随负荷的(de)(de)增大而(er)降落，灯泡的(de)(de)耗(hao)费功(gong)率随电(dian)(dian)(dian)(dian)压(ya)变化(hua)而(er)改动。我们也能够经(jing)过(guo)计算找出(chu)(chu)输(shu)(shu)出(chu)(chu)电(dian)(dian)(dian)(dian)压(ya)和功(gong)率的(de)(de)关系。但实践上由于(yu)电(dian)(dian)(dian)(dian)灯泡的(de)(de)电(dian)(dian)(dian)(dian)阻会随受加在两端电(dian)(dian)(dian)(dian)压(ya)变化(hua)而(er)改动，并(bing)且输(shu)(shu)出(chu)(chu)电(dian)(dian)(dian)(dian)压(ya)、电(dian)(dian)(dian)(dian)流(liu)也不是(shi)(shi)正弦波，所(suo)以这种(zhong)的(de)(de)计算只(zhi)能看作(zuo)是(shi)(shi)预算。

以负载为60W的(de)电(dian)(dian)灯(deng)泡(pao)为例：假定(ding)灯(deng)泡(pao)的(de)电(dian)(dian)阻不随电(dian)(dian)压(ya)变化而改动。由于(yu)R灯(deng)=V2/W=2102/60=735Ω，所以在电(dian)(dian)压(ya)为208V时(shi)，W=V2/R=2082/735=58.9W.由此可折算出电(dian)(dian)压(ya)和功率的(de)关系。经(jing)过测试(shi)，我们发现当输出功率约为100W时(shi)，输入电(dian)(dian)流为10A.此时(shi)输出电(dian)(dian)压(ya)为200V。

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