电子逆(ni)变器电路(lu)图详解 电子逆(ni)变器电路(lu)图原理大全(quan) KIA MOS管(guan)
信息来(lai)源:本站 日期:2018-04-23
逆变(bian)器是(shi)通(tong)过半(ban)导(dao)体功率开关的开通(tong)和关断作(zuo)用,把直(zhi)流电(dian)(dian)能转变(bian)成交流电(dian)(dian)能的一(yi)种变(bian)换(huan)装置(zhi),是(shi)整流变(bian)换(huan)的逆过程。
工作原理
逆(ni)(ni)(ni)变(bian)(bian)装置的(de)(de)核心(xin),是逆(ni)(ni)(ni)变(bian)(bian)开关(guan)电(dian)(dian)路(lu),简称为逆(ni)(ni)(ni)变(bian)(bian)电(dian)(dian)路(lu)。该电(dian)(dian)路(lu)通过电(dian)(dian)力电(dian)(dian)子开关(guan)的(de)(de)导通与关(guan)断,来(lai)完成逆(ni)(ni)(ni)变(bian)(bian)的(de)(de)功能(neng)。
特点
(1)要求具有较高的效率。
由(you)于目前太(tai)阳(yang)能(neng)电(dian)池(chi)的价格(ge)偏高,为了最(zui)大限度的利用太(tai)阳(yang)能(neng)电(dian)池(chi),提高系(xi)统效率(lv),必须设法提高逆变器的效率(lv)。
(2)要求具(ju)有较高的可靠性。
目前光(guang)伏电站(zhan)系(xi)统主要用于边(bian)远地区,许多电站(zhan)无(wu)人值守(shou)和维护,这就要求(qiu)逆(ni)变(bian)器有合理的电路结构(gou),严格的元器件筛(shai)选(xuan),并(bing)要求(qiu)逆(ni)变(bian)器具备(bei)各种保护功能,如:输(shu)入直(zhi)流极(ji)性接反保护、交流输(shu)出短路保护、过热、过载保护等(deng)。
(3)要求输入电压有较宽的适应(ying)范围。
由于太阳能(neng)电(dian)(dian)池(chi)的(de)端(duan)(duan)电(dian)(dian)压(ya)随负(fu)载(zai)和日照(zhao)强度变化而变化。特(te)别是当蓄电(dian)(dian)池(chi)老化时其端(duan)(duan)电(dian)(dian)压(ya)的(de)变化范围很大,如12V的(de)蓄电(dian)(dian)池(chi),其端(duan)(duan)电(dian)(dian)压(ya)可能(neng)在10V~16V之(zhi)间变化,这就要求逆变器在较大的(de)直流输入(ru)电(dian)(dian)压(ya)范围内(nei)保证正常工作。
逆变(bian)器是通过半导体功率(lv)开关的(de)开通和关断(duan)作(zuo)用,把(ba)直流电能转变(bian)成交流电能的(de)一种变(bian)换装(zhuang)置,是整流变(bian)换的(de)逆过程。
车(che)载逆变器的(de)整个电(dian)(dian)路(lu)大(da)体(ti)上(shang)可分(fen)(fen)为两大(da)部分(fen)(fen),每部分(fen)(fen)各采用(yong)一只TL494或KA7500芯片组成控制(zhi)(zhi)电(dian)(dian)路(lu),其中(zhong)第一部分(fen)(fen)电(dian)(dian)路(lu)的(de)作(zuo)(zuo)用(yong)是将汽车(che)电(dian)(dian)瓶等提供的(de)12V直(zhi)流(liu)(liu)(liu)电(dian)(dian),通过(guo)高频PWM (脉宽调制(zhi)(zhi))开(kai)关电(dian)(dian)源技术转换成30kHz-50kHz、220V左(zuo)右的(de)交流(liu)(liu)(liu)电(dian)(dian);第二部分(fen)(fen)电(dian)(dian)路(lu)的(de)作(zuo)(zuo)用(yong)则(ze)是利用(yong)桥式(shi)整流(liu)(liu)(liu)、滤波、脉宽调制(zhi)(zhi)及开(kai)关功率输出等技术,将30kHz~50kHz、220V左(zuo)右的(de)交流(liu)(liu)(liu)电(dian)(dian)转换成50Hz、220V的(de)交流(liu)(liu)(liu)电(dian)(dian)。
(1)脚(jiao)(jiao)第一(yi)组放大(da)(da)(da)器(qi)的(de)同相(xiang)输(shu)(shu)(shu)(shu)(shu)(shu)(shu)入(ru)(ru)端(duan)(duan),检测输(shu)(shu)(shu)(shu)(shu)(shu)(shu)出(chu)(chu)电(dian)(dian)流(liu)(liu),与(yu)(yu)3个(ge)0.33R 电(dian)(dian)阻分(fen)压(ya)(ya),当(dang)电(dian)(dian)流(liu)(liu)过(guo)大(da)(da)(da)时(shi)(shi)(shi),分(fen)压(ya)(ya)电(dian)(dian)阻上的(de)电(dian)(dian)压(ya)(ya)超过(guo)(2)脚(jiao)(jiao)基准电(dian)(dian)压(ya)(ya),(3)脚(jiao)(jiao)放大(da)(da)(da)器(qi)输(shu)(shu)(shu)(shu)(shu)(shu)(shu)出(chu)(chu)端(duan)(duan)输(shu)(shu)(shu)(shu)(shu)(shu)(shu)出(chu)(chu)高(gao)电(dian)(dian)平(ping),(3)脚(jiao)(jiao)为(wei)高(gao)电(dian)(dian)平(ping)时(shi)(shi)(shi),电(dian)(dian)路进(jin)入(ru)(ru)保护状态(tai)。(2)脚(jiao)(jiao)为(wei)比(bi)(bi)较器(qi)的(de)反相(xiang)输(shu)(shu)(shu)(shu)(shu)(shu)(shu)入(ru)(ru)端(duan)(duan),接(14)脚(jiao)(jiao)基准,作(zuo)比(bi)(bi)较器(qi)的(de)参(can)考电(dian)(dian)压(ya)(ya),外部(bu)输(shu)(shu)(shu)(shu)(shu)(shu)(shu)入(ru)(ru)端(duan)(duan)的(de)控制(zhi)信号可(ke)(ke)输(shu)(shu)(shu)(shu)(shu)(shu)(shu)入(ru)(ru)至(zhi)脚(jiao)(jiao)(4)的(de)截止(zhi)时(shi)(shi)(shi)间控制(zhi)端(duan)(duan)(也叫死区时(shi)(shi)(shi)间控制(zhi)),与(yu)(yu)脚(jiao)(jiao)(1)、(2)、(15)、(16)误差(cha)放大(da)(da)(da)器(qi)的(de)输(shu)(shu)(shu)(shu)(shu)(shu)(shu)入(ru)(ru)端(duan)(duan),其输(shu)(shu)(shu)(shu)(shu)(shu)(shu)入(ru)(ru)端(duan)(duan)点的(de)抵补电(dian)(dian)压(ya)(ya)为(wei)120mV,其可(ke)(ke)限制(zhi)输(shu)(shu)(shu)(shu)(shu)(shu)(shu)出(chu)(chu)截止(zhi)时(shi)(shi)(shi)间至(zhi)最(zui)小值,大(da)(da)(da)约(yue)为(wei)最(zui)初锯齿波周期(qi)时(shi)(shi)(shi)间的(de)4%。当(dang)13脚(jiao)(jiao)的(de)输(shu)(shu)(shu)(shu)(shu)(shu)(shu)出(chu)(chu)模控制(zhi)端(duan)(duan)接地时(shi)(shi)(shi),可(ke)(ke)获得(de)96%最(zui)大(da)(da)(da)工(gong)作(zuo)周期(qi),而当(dang)(13)脚(jiao)(jiao)接制(zhi)参(can)考电(dian)(dian)压(ya)(ya)时(shi)(shi)(shi),可(ke)(ke)获得(de)48%最(zui)大(da)(da)(da)工(gong)作(zuo)周期(qi)。如果我们在第4脚(jiao)(jiao)截止(zhi)时(shi)(shi)(shi)间控制(zhi)输(shu)(shu)(shu)(shu)(shu)(shu)(shu)入(ru)(ru)端(duan)(duan)设定(ding)(ding)一(yi)个(ge)固(gu)定(ding)(ding)电(dian)(dian)压(ya)(ya),其范(fan)围由(you)0V至(zhi)3.3V之间,则(ze)附(fu)加的(de)截止(zhi)时(shi)(shi)(shi)间一(yi)定(ding)(ding)出(chu)(chu)现在输(shu)(shu)(shu)(shu)(shu)(shu)(shu)出(chu)(chu)上。 (5)、(6)脚(jiao)(jiao)是(shi)一(yi)个(ge)固(gu)定(ding)(ding)频(pin)率的(de)脉(mai)冲(chong)宽度调制(zhi)电(dian)(dian)路,内置了线性锯齿波振荡器(qi),振荡频(pin)率可(ke)(ke)通(tong)过(guo)外部(bu)的(de)一(yi)个(ge)电(dian)(dian)阻和一(yi)个(ge)电(dian)(dian)容进(jin)行调节,其振荡频(pin)率如下(xia):
输(shu)(shu)(shu)(shu)(shu)出脉冲的(de)(de)(de)(de)宽(kuan)度(du)是(shi)通(tong)过电(dian)(dian)(dian)容CT上(shang)的(de)(de)(de)(de)正极性(xing)锯齿波电(dian)(dian)(dian)压(ya)与另外两个(ge)控(kong)(kong)制(zhi)信(xin)号进行比较来实现。功(gong)率输(shu)(shu)(shu)(shu)(shu)出管Q1和Q2受控(kong)(kong)于或非门。当(dang)双稳触(chu)发(fa)(fa)器(qi)的(de)(de)(de)(de)时(shi)钟信(xin)号为低(di)电(dian)(dian)(dian)平时(shi)才(cai)会(hui)被选通(tong),即只有在(zai)(zai)锯齿波电(dian)(dian)(dian)压(ya)大(da)(da)于控(kong)(kong)制(zhi)信(xin)号期间才(cai)会(hui)被选通(tong)。当(dang)控(kong)(kong)制(zhi)信(xin)号增大(da)(da),输(shu)(shu)(shu)(shu)(shu)出脉冲的(de)(de)(de)(de)宽(kuan)度(du)将减小。(7)脚(jiao)(jiao)接地端(duan),(8)、(11)脚(jiao)(jiao)是(shi)Q1和Q2内部开关管的(de)(de)(de)(de)集电(dian)(dian)(dian)极,在(zai)(zai)此(ci)电(dian)(dian)(dian)路(lu)(lu)中(zhong)接电(dian)(dian)(dian)源,(9)、(10)脚(jiao)(jiao)为Q1、Q2的(de)(de)(de)(de)发(fa)(fa)射极,作开关管驱动(dong)输(shu)(shu)(shu)(shu)(shu)出端(duan),接下图(tu)中(zhong)Q1与Q2外部放(fang)大(da)(da)电(dian)(dian)(dian)路(lu)(lu)。以驱动(dong)后极推挽电(dian)(dian)(dian)路(lu)(lu)。(12)脚(jiao)(jiao)电(dian)(dian)(dian)源端(duan),(13)脚(jiao)(jiao)为输(shu)(shu)(shu)(shu)(shu)出控(kong)(kong)制(zhi)端(duan),接(14)脚(jiao)(jiao)基(ji)准(zhun)电(dian)(dian)(dian)压(ya)时(shi)两路(lu)(lu)输(shu)(shu)(shu)(shu)(shu)出脉冲相差180方位,每(mei)路(lu)(lu)输(shu)(shu)(shu)(shu)(shu)出量大(da)(da)约200MA的(de)(de)(de)(de)驱动(dong)推挽或半桥式电(dian)(dian)(dian)路(lu)(lu)。(15)、脚(jiao)(jiao)第二组(zu)放(fang)大(da)(da)器(qi)的(de)(de)(de)(de)反相输(shu)(shu)(shu)(shu)(shu)入(ru)(ru)端(duan),接基(ji)准(zhun)电(dian)(dian)(dian)压(ya), (16)脚(jiao)(jiao)同相输(shu)(shu)(shu)(shu)(shu)入(ru)(ru)端(duan),检(jian)测(ce)电(dian)(dian)(dian)源电(dian)(dian)(dian)压(ya)。当(dang)电(dian)(dian)(dian)压(ya)过高超过(15)脚(jiao)(jiao)参(can)考电(dian)(dian)(dian)压(ya)时(shi),(3)脚(jiao)(jiao)输(shu)(shu)(shu)(shu)(shu)出高电(dian)(dian)(dian)平,电(dian)(dian)(dian)路(lu)(lu)进入(ru)(ru)保(bao)护状态。
这是(shi)一个推挽式(shi)拓扑逆变(bian)电路,当(dang)E1驱动脉冲(chong)驱动时(shi),Q1导(dao)通(tong),使VT3、VT6导(dao)通(tong),VT7、VT8截止(zhi),此(ci)时(shi)电路进(jin)(jin)行(xing)正半周波形(xing)放(fang)大,变(bian)压(ya)器升压(ya)到次级,通(tong)过高(gao)频整(zheng)流(liu)管整(zheng)流(liu),当(dang)E2脉冲(chong)驱动时(shi),Q2导(dao)通(tong),驱动VT7、VT8导(dao)通(tong)。VT3、VT6截止(zhi),进(jin)(jin)得负半周波形(xing)放(fang)大。经升压(ya)变(bian)压(ya)器升压(ya)后(hou),高(gao)频整(zheng)流(liu)。
(此VT3\6\7\8以(yi)推挽方式存(cun)在于电(dian)路(lu)中,各负(fu)责正负(fu)半周(zhou)的(de)波形(xing)放大(da)任务,电(dian)路(lu)工作时,两(liang)只(zhi)对称的(de)功(gong)率开关管每次只(zhi)有(you)一对导(dao)(dao)通,所以(yi)导(dao)(dao)通损(sun)耗小效率高(gao)。推挽输出既(ji)可以(yi)向负(fu)载(zai)灌电(dian)流.)
最后由(you)(you)TL494CN芯片的5脚(jiao)外接(jie)点容C3和(he)(he)(he)(he)6脚(jiao)外接(jie)电(dian)(dian)阻R15决定脉宽频(pin)率(lv)为(wei)(wei)(wei)F=1.1÷(0.1×220)KHZ=50HZ控制Q10、Q11、Q13、Q14工(gong)作(zuo)在50HZ的频(pin)率(lv)下(xia),将(jiang)220V直(zhi)流(liu)(liu)电(dian)(dian)逆变(bian)(bian)为(wei)(wei)(wei)220V/50HZ的交流(liu)(liu)电(dian)(dian),上图将(jiang)完成(cheng)(cheng)这部分功能。TL494正向(xiang)(xiang)时,IC2控制Q3为(wei)(wei)(wei)饱(bao)和(he)(he)(he)(he)导通状(zhuang)(zhuang)(zhuang)态(tai)(tai)(tai)(tai),Q4为(wei)(wei)(wei)截止(zhi)(zhi)状(zhuang)(zhuang)(zhuang)态(tai)(tai)(tai)(tai),由(you)(you)于(yu)Q3为(wei)(wei)(wei)饱(bao)和(he)(he)(he)(he)导通状(zhuang)(zhuang)(zhuang)态(tai)(tai)(tai)(tai),则Q10为(wei)(wei)(wei)饱(bao)和(he)(he)(he)(he)导通状(zhuang)(zhuang)(zhuang)态(tai)(tai)(tai)(tai)。由(you)(you)于(yu)Q4处(chu)于(yu)截止(zhi)(zhi)状(zhuang)(zhuang)(zhuang)态(tai)(tai)(tai)(tai),Q11因(yin)栅(zha)极无(wu)正偏(pian)(pian)压(ya)而(er)处(chu)于(yu)截止(zhi)(zhi)状(zhuang)(zhuang)(zhuang)态(tai)(tai)(tai)(tai),同时Q14因(yin)栅(zha)极无(wu)正偏(pian)(pian)压(ya)而(er)处(chu)于(yu)截止(zhi)(zhi)状(zhuang)(zhuang)(zhuang)态(tai)(tai)(tai)(tai), Q13为(wei)(wei)(wei)饱(bao)和(he)(he)(he)(he)导通状(zhuang)(zhuang)(zhuang)态(tai)(tai)(tai)(tai)。此时220V直(zhi)流(liu)(liu)电(dian)(dian)经(jing)(jing)(jing)VT6沿XAC插座到负(fu)载(zai)再经(jing)(jing)(jing)VT10接(jie)地,形(xing)(xing)成(cheng)(cheng)正半(ban)周期电(dian)(dian)流(liu)(liu);反(fan)向(xiang)(xiang)时,IC2控制Q3为(wei)(wei)(wei)截止(zhi)(zhi)状(zhuang)(zhuang)(zhuang)态(tai)(tai)(tai)(tai),Q4为(wei)(wei)(wei)饱(bao)和(he)(he)(he)(he)导通状(zhuang)(zhuang)(zhuang)态(tai)(tai)(tai)(tai),由(you)(you)于(yu)Q3为(wei)(wei)(wei)截止(zhi)(zhi)状(zhuang)(zhuang)(zhuang)态(tai)(tai)(tai)(tai),则Q10、Q13因(yin)栅(zha)极无(wu)正偏(pian)(pian)压(ya)而(er)处(chu)于(yu)截止(zhi)(zhi)状(zhuang)(zhuang)(zhuang)态(tai)(tai)(tai)(tai),由(you)(you)于(yu)Q4为(wei)(wei)(wei)饱(bao)和(he)(he)(he)(he)导通状(zhuang)(zhuang)(zhuang)态(tai)(tai)(tai)(tai),Q11处(chu)于(yu)饱(bao)和(he)(he)(he)(he)导通状(zhuang)(zhuang)(zhuang)态(tai)(tai)(tai)(tai),同时Q14处(chu)于(yu)饱(bao)和(he)(he)(he)(he)导通状(zhuang)(zhuang)(zhuang)态(tai)(tai)(tai)(tai),Q11因(yin)栅(zha)极无(wu)正偏(pian)(pian)压(ya)而(er)处(chu)于(yu)截止(zhi)(zhi)状(zhuang)(zhuang)(zhuang)态(tai)(tai)(tai)(tai)。此时220V直(zhi)流(liu)(liu)电(dian)(dian)经(jing)(jing)(jing)VT9沿XAC插座到负(fu)载(zai)再经(jing)(jing)(jing)VT7接(jie)地,形(xing)(xing)成(cheng)(cheng)负(fu)半(ban)周期电(dian)(dian)流(liu)(liu);这样(yang)接(jie)将(jiang)220V直(zhi)流(liu)(liu)电(dian)(dian)成(cheng)(cheng)功转变(bian)(bian)为(wei)(wei)(wei)220V/50HZ交流(liu)(liu)电(dian)(dian)输出供负(fu)载(zai)使用。
电(dian)(dian)路中(zhong)采用双运(yun)放(fang)(fang)比较放(fang)(fang)大(da)器(qi)LM358来控制输(shu)(shu)(shu)出(chu)(chu)过流保护(hu),输(shu)(shu)(shu)出(chu)(chu)电(dian)(dian)压(ya)(ya)(ya)(ya)过低保护(hu)电(dian)(dian)路,TL431在此(ci)设制2.5V基(ji)准电(dian)(dian)压(ya)(ya)(ya)(ya),给(ji)比较器(qi)同相输(shu)(shu)(shu)入(ru)端(duan)(duan)作参考(kao)电(dian)(dian)压(ya)(ya)(ya)(ya),第一组运(yun)放(fang)(fang)的(de)同相输(shu)(shu)(shu)入(ru)端(duan)(duan)接(jie)输(shu)(shu)(shu)出(chu)(chu)电(dian)(dian)流检测(ce)(ce),反(fan)相输(shu)(shu)(shu)入(ru)端(duan)(duan)接(jie)参考(kao)电(dian)(dian)压(ya)(ya)(ya)(ya),当(dang)电(dian)(dian)流过大(da),比较器(qi)输(shu)(shu)(shu)入(ru)电(dian)(dian)压(ya)(ya)(ya)(ya)升高,当(dang)超过2.5V时(shi),输(shu)(shu)(shu)出(chu)(chu)端(duan)(duan)输(shu)(shu)(shu)出(chu)(chu)高电(dian)(dian)平(ping),送入(ru)IC1的(de)3脚,IC关(guan)闭输(shu)(shu)(shu)出(chu)(chu)。第二(er)组运(yun)放(fang)(fang)同相输(shu)(shu)(shu)入(ru)端(duan)(duan)接(jie)参考(kao)电(dian)(dian)压(ya)(ya)(ya)(ya),反(fan)相输(shu)(shu)(shu)入(ru)端(duan)(duan)接(jie)输(shu)(shu)(shu)出(chu)(chu)电(dian)(dian)压(ya)(ya)(ya)(ya),当(dang)电(dian)(dian)压(ya)(ya)(ya)(ya)过低,检测(ce)(ce)分压(ya)(ya)(ya)(ya)后(hou)电(dian)(dian)压(ya)(ya)(ya)(ya)低于2.5V时(shi),输(shu)(shu)(shu)出(chu)(chu)端(duan)(duan)输(shu)(shu)(shu)出(chu)(chu)高电(dian)(dian)平(ping),Q1导通,蜂鸣器(qi)报警。
中小功率
中(zhong)小功率逆变(bian)电源(yuan)是(shi)户(hu)用独立交流(liu)光伏系统中(zhong)重要的环(huan)节之(zhi)一,因而各国的光伏专家们一直(zhi)在努力(li)开发(fa)适(shi)于户(hu)用的逆变(bian)电源(yuan),以促(cu)使该(gai)行业更好更快地发(fa)展。
多重串联型
多重串联型逆变器(qi)应用于电(dian)动(dong)汽车有诸多优点。串联结构(gou)输出(chu)电(dian)压矢量种类大(da)大(da)增(zeng)加,增(zeng)强了(le)控制的(de)灵活(huo)性(xing),提(ti)高(gao)了(le)控制的(de)精确性(xing);同时降低(di)了(le)电(dian)机中(zhong)性(xing)点电(dian)压的(de)波动(dong)。逆变器(qi)的(de)旁路特点可提(ti)高(gao)充电(dian)和再生(sheng)制动(dong)控制的(de)灵活(huo)性(xing)。
随着人(ren)们对城市环境的(de)(de)日益关(guan)切,电(dian)(dian)动(dong)汽(qi)车(che)的(de)(de)发(fa)展得(de)到了一个难(nan)得(de)的(de)(de)机遇。在城市交通(tong)中,电(dian)(dian)动(dong)大客(ke)车(che)由于载量大,综(zong)合效(xiao)益高(gao)(gao),成为(wei)优先发(fa)展的(de)(de)对象(xiang)。电(dian)(dian)动(dong)大客(ke)车(che)大都采用(yong)三相交流(liu)电(dian)(dian)机,由于电(dian)(dian)机功率大,三相逆(ni)变(bian)器(qi)中的(de)(de)器(qi)件需(xu)要(yao)承受高(gao)(gao)电(dian)(dian)压和(he)大电(dian)(dian)流(liu)应(ying)力(li)的(de)(de)作用(yong),较(jiao)高(gao)(gao)的(de)(de)dv/dt又使电(dian)(dian)磁辐(fu)射(she)严重,并且(qie)需(xu)要(yao)良好(hao)的(de)(de)散热。
而采(cai)用多重串联(lian)型结构的大功率(lv)逆变器则降(jiang)(jiang)低了(le)单个器件(jian)(jian)承受的电压应力,降(jiang)(jiang)低了(le)对器件(jian)(jian)的要求;降(jiang)(jiang)低了(le)dv/dt值,减少(shao)(shao)了(le)电磁辐射,器件(jian)(jian)的发热也大大减少(shao)(shao);由于输出电平种类增加,控制性能(neng)更好。
多(duo)重串联型(xing)逆变器适用(yong)(yong)于大(da)功率的电(dian)动(dong)汽车驱动(dong)系统(tong)。采用(yong)(yong)多(duo)重串联型(xing)结构,可降低(di)多(duo)个蓄电(dian)池串联带来的危险,降低(di)器件的开关应力和减少电(dian)磁辐(fu)射。但需要的电(dian)池数增(zeng)加了(le)2倍。
多(duo)重串联型结构(gou)输出电压(ya)矢量种(zhong)类大(da)(da)大(da)(da)增加(jia),从(cong)而增强了控制(zhi)的(de)灵(ling)活(huo)性,提高了控制(zhi)的(de)精确性;同时(shi)降(jiang)低电机(ji)中性点电压(ya)的(de)波动(dong)。为维持每组蓄(xu)(xu)电池电量的(de)均(jun)衡,在(zai)运行时(shi)需要确保电池的(de)放电时(shi)间(jian)一致。通(tong)过旁(pang)路方式,可灵(ling)活(huo)地对蓄(xu)(xu)电池组充电,还可控制(zhi)再(zai)生(sheng)制(zhi)动(dong)的(de)力矩。
车载
车(che)(che)载(zai)(zai)逆(ni)变器(qi)一(yi)般(ban)使(shi)用(yong)(yong)汽车(che)(che)电(dian)(dian)瓶或(huo)者(zhe)点烟(yan)器(qi)供电(dian)(dian),先将(jiang)(jiang)低压(ya)直流(liu)(liu)电(dian)(dian)转(zhuan)换为265V左右的(de)(de)直流(liu)(liu)电(dian)(dian),然后将(jiang)(jiang)高压(ya)的(de)(de)直流(liu)(liu)电(dian)(dian)转(zhuan)变为220V、50Hz的(de)(de)交流(liu)(liu)电(dian)(dian)。车(che)(che)载(zai)(zai)逆(ni)变器(qi)打破了在(zai)车(che)(che)内(nei)使(shi)用(yong)(yong)电(dian)(dian)器(qi)的(de)(de)诸多(duo)局限。车(che)(che)载(zai)(zai)电(dian)(dian)源不仅适用(yong)(yong)于(yu)车(che)(che)载(zai)(zai)系统(tong),只(zhi)要有DC12V直流(liu)(liu)电(dian)(dian)源的(de)(de)场合,都可使(shi)用(yong)(yong)。车(che)(che)载(zai)(zai)逆(ni)变器(qi)充(chong)分(fen)考虑到外部的(de)(de)使(shi)用(yong)(yong)环境,当(dang)发(fa)生(sheng)过载(zai)(zai)或(huo)短路现象时将(jiang)(jiang)自动保护(hu)关机。
电(dian)压(ya)源逆(ni)(ni)变(bian)器是(shi)按照控(kong)制电(dian)压(ya)的方式将直流电(dian)能转变(bian)为(wei)交流电(dian)能, 是(shi)逆(ni)(ni)变(bian)技术中(zhong)最为(wei)常(chang)见和简(jian)单的一种,下(xia)面主要(yao)介绍单相电(dian)压(ya)源逆(ni)(ni)变(bian)器。
要从一(yi)个(ge)(ge)直流(liu)电源中获取交流(liu)电能,有(you)(you)(you)多(duo)种方(fang)式(shi),但至少应使用两个(ge)(ge)功率(lv)开关元件,单(dan)相逆变器有(you)(you)(you)推挽式(shi)、半(ban)(ban)桥(qiao)式(shi)、全桥(qiao)式(shi)三种电路拓朴(po)结构,如果(guo)(guo)每半(ban)(ban)个(ge)(ge)工频周(zhou)期(qi)内只输出(chu)一(yi)个(ge)(ge)脉(mai)冲(chong),我们称其为方(fang)波逆变器,如果(guo)(guo)每半(ban)(ban)个(ge)(ge)周(zhou)期(qi)内有(you)(you)(you)多(duo)个(ge)(ge)脉(mai)宽组(zu)成,并且脉(mai)冲(chong)宽度符(fu)合正弦波调制(SPWM)规律,则称其为正弦波脉(mai)宽调制输出(chu)。方(fang)波逆变技(ji)术(shu)实质(zhi)上是一(yi)个(ge)(ge)单(dan)脉(mai)冲(chong)调制技(ji)术(shu),下面介绍其工作原(yuan)理。
下图是单相推挽式逆变器的拓朴(po)结构(gou),该电路由两只(zhi)共负极的功率开关(guan)元件和一个初级(ji)带有中心抽头的升压(ya)变压(ya)器组成。
若交(jiao)流负(fu)(fu)载为纯阻性(xing)负(fu)(fu)载,当(dang) t 1 ≤t≤t 2 时(shi) VT 1 功率管(guan)加(jia)上(shang)栅(zha)极(ji)驱动信(xin)号 Ug1,VT 1 导通,VT 2 截止(zhi),变压(ya)器输出端(duan)感(gan)应(ying)出正电(dian)压(ya);当(dang) t 3 ≤t≤t 4 时(shi),VT 2 功率管(guan)加(jia)上(shang)栅(zha)极(ji)驱动信(xin)号 Ug2,VT 2 导通,VT 1 截止(zhi),变压(ya)器输出端(duan)感(gan)应(ying)出负(fu)(fu)电(dian)压(ya),波形(xing)如图下图所示(shi),若负(fu)(fu)载为感(gan)性(xing)负(fu)(fu)载,则变压(ya)器内的电(dian)流波形(xing)连续,输出电(dian)压(ya)、电(dian)流波形(xing)如下图推挽电(dian)路波形(xing)。
推(tui)挽(wan)逆变(bian)器的(de)(de)输(shu)出只有两(liang)种状态+V0 和(he)-V0 ,实质(zhi)上是(shi)双(shuang)极性调制,通过调节 VT1 和(he) VT2 的(de)(de)占空比来(lai)调节输(shu)出电(dian)(dian)(dian)压(ya)(ya)(ya)。推(tui)挽(wan)式方波逆变(bian)器的(de)(de)电(dian)(dian)(dian)路拓朴结构简单,两(liang)个功(gong)率管可共地驱动(dong),但功(gong)率管承受(shou)开关电(dian)(dian)(dian)压(ya)(ya)(ya)为 2 倍的(de)(de)直(zhi)流电(dian)(dian)(dian)压(ya)(ya)(ya),因此适合应用于直(zhi)流母线电(dian)(dian)(dian)压(ya)(ya)(ya)较(jiao)低(di)的(de)(de)场(chang)合。另外,变(bian)压(ya)(ya)(ya)器的(de)(de)利用率较(jiao)低(di),驱动(dong)感性负载困难(nan)。
半桥(qiao)式逆变电(dian)(dian)(dian)路的(de)(de)(de)拓朴(po)结构如图 2-4 所示,两(liang)只(zhi)串联(lian)电(dian)(dian)(dian)容(rong)(rong)的(de)(de)(de)中点作为参考(kao)点,当开关元件(jian) VT 1 导(dao)(dao)通时,电(dian)(dian)(dian)容(rong)(rong) C 1 上的(de)(de)(de)能量释(shi)放(fang)到负载(zai)(zai) RL 上,而当 VT 2 导(dao)(dao)通时,电(dian)(dian)(dian)容(rong)(rong)C 2 上的(de)(de)(de)能量释(shi)放(fang)到负载(zai)(zai) RL 上,VT 1 和 VT 2 轮流(liu)导(dao)(dao)通时在负载(zai)(zai)两(liang)端(duan)获得了(le)交流(liu)电(dian)(dian)(dian)能,半桥(qiao)逆变电(dian)(dian)(dian)路在功率(lv)(lv)开关元件(jian)不导(dao)(dao)通时承受直流(liu)电(dian)(dian)(dian)源(yuan)电(dian)(dian)(dian)压 Ud,由于电(dian)(dian)(dian)容(rong)(rong) C 1 和 C 2 两(liang)端(duan)的(de)(de)(de)电(dian)(dian)(dian)压均为 Ud/2(假设 C 1 =C 2 ) ,因此功率(lv)(lv)元件(jian) VT 1 和 VT 2 承受的(de)(de)(de)电(dian)(dian)(dian)流(liu)为 2Id。实质上单相半桥(qiao)电(dian)(dian)(dian)路和前一节讨论的(de)(de)(de)单相推挽(wan)电(dian)(dian)(dian)路在电(dian)(dian)(dian)路结构上是对(dui)偶的(de)(de)(de),读(du)者可自行分析(xi)半桥(qiao)电(dian)(dian)(dian)路的(de)(de)(de)工作过(guo)程。
半桥型(xing)逆(ni)变电(dian)路(lu)(lu)结构(gou)简单,由于两只串联电(dian)容(rong)的(de)作(zuo)用,不会产生磁偏或直流分量(liang)(liang),非(fei)常适合后级带动变压器负载,当(dang)该电(dian)路(lu)(lu)工(gong)作(zuo)在(zai)工(gong)频(pin)(50 或者 60H Z )时,电(dian)容(rong)必须选(xuan)取较大的(de)容(rong)量(liang)(liang),使电(dian)路(lu)(lu)的(de)成(cheng)本上(shang)升,因此(ci)该电(dian)路(lu)(lu)主要用于高频(pin)逆(ni)变场合。
单(dan)相全桥(qiao)逆变电(dian)(dian)路也称“H 桥(qiao)”电(dian)(dian)路,其电(dian)(dian)路拓朴结构如(ru)图所示(shi),由(you)两个半桥(qiao)电(dian)(dian)路组成, 以(yi) 180度方波为例说明单(dan)相全桥(qiao)电(dian)(dian)路的工作原理, 功(gong)率开关(guan)元件 Q 1 与(yu) Q 4 互(hu)补,Q 2 与(yu) Q 3 互(hu)补,当(dang) Q 1 与(yu) Q 3 同(tong)(tong)时(shi)(shi)导通时(shi)(shi),负载电(dian)(dian)压 U 0 = +Ud;当(dang) Q 2 与(yu) Q 4 同(tong)(tong)时(shi)(shi)悼通时(shi)(shi),负载两端 U 0 = -Ud,Q 1 Q 3 和 Q 2 Q 4 轮(lun)流导通,负载两端就得(de)到交流电(dian)(dian)能。
假设负(fu)载(zai)具有一定电(dian)感,即负(fu)载(zai)电(dian)流(liu)(liu)落后(hou)(hou)与(yu)电(dian)压(ya) j 角(jiao)(jiao)度,在(zai) Q1Q3 功率管栅(zha)(zha)极加上(shang)驱动信(xin)(xin)号时,由于(yu)电(dian)流(liu)(liu)的(de)带后(hou)(hou),此时 D1 D3 仍处于(yu)导通续(xu)流(liu)(liu)阶段(duan),当经过(guo) y 电(dian)角(jiao)(jiao)度时,电(dian)流(liu)(liu)过(guo)零,电(dian)源向(xiang)负(fu)载(zai)输送有功功率,同样当 Q2 Q4 加上(shang)栅(zha)(zha)极驱动信(xin)(xin)号时 D2D4 仍处于(yu)续(xu)流(liu)(liu)状态,此时能量(liang)从负(fu)载(zai)馈送回直流(liu)(liu)侧,再经过(guo) y 电(dian)角(jiao)(jiao)度后(hou)(hou),Q2 Q4 才真正流(liu)(liu)过(guo)电(dian)流(liu)(liu)。
单相全桥电路(lu)上(shang)述工(gong)作状况下(xia) Q1Q3 和(he) Q2Q4 分别工(gong)作半个周(zhou)期(qi), 其输出电压波形为(wei) 180 度的方波,事实(shi)上(shang)这种(zhong)控制(zhi)方式(shi)并不实(shi)用,因(yin)为(wei)在(zai)实(shi)际的逆变电源(yuan)中(zhong)输出电压是(shi)需(xu)要可以控制(zhi)和(he)调节(jie)的。
实例(li)讲解
以上是(shi)一款较为容易制作(zuo)的(de)(de)(de)逆变(bian)(bian)器(qi)电(dian)(dian)(dian)路图,可以将(jiang)12V直流电(dian)(dian)(dian)源(yuan)电(dian)(dian)(dian)压(ya)逆变(bian)(bian)为220V市电(dian)(dian)(dian)电(dian)(dian)(dian)压(ya),电(dian)(dian)(dian)路由BG2和(he)(he)BG3组(zu)成的(de)(de)(de)多谐振(zhen)荡器(qi)推(tui)动(dong),再(zai)通过BG1和(he)(he)BG4驱动(dong),来控制BG6和(he)(he)BG7工作(zuo)。其(qi)中振(zhen)荡电(dian)(dian)(dian)路由BG5与(yu)DW组(zu)的(de)(de)(de)稳(wen)压(ya)电(dian)(dian)(dian)源(yuan)供电(dian)(dian)(dian),这(zhei)样可以使输(shu)出(chu)频率比较稳(wen)定(ding)。在制作(zuo)时(shi),变(bian)(bian)压(ya)器(qi)可选(xuan)有常用双(shuang)12V输(shu)出(chu)的(de)(de)(de)市电(dian)(dian)(dian)变(bian)(bian)压(ya)器(qi)。可根据需要,选(xuan)择适当的(de)(de)(de)12V蓄电(dian)(dian)(dian)池容量。
以下是(shi)(shi)一款高效(xiao)率的(de)正(zheng)弦波(bo)逆变(bian)器(qi)电(dian)器(qi)图(tu),该电(dian)路(lu)用12V电(dian)池供电(dian)。先用一片(pian)倍压模块倍压为(wei)(wei)运(yun)(yun)(yun)(yun)放(fang)(fang)(fang)供电(dian)。可选取ICL7660或MAX1044。运(yun)(yun)(yun)(yun)放(fang)(fang)(fang)1产生50Hz正(zheng)弦波(bo)作(zuo)(zuo)为(wei)(wei)基准信号。运(yun)(yun)(yun)(yun)放(fang)(fang)(fang)2作(zuo)(zuo)为(wei)(wei)反相(xiang)(xiang)器(qi)。运(yun)(yun)(yun)(yun)放(fang)(fang)(fang)3和(he)(he)运(yun)(yun)(yun)(yun)放(fang)(fang)(fang)4作(zuo)(zuo)为(wei)(wei)迟滞(zhi)比(bi)较器(qi)。其实(shi)(shi)运(yun)(yun)(yun)(yun)放(fang)(fang)(fang)3和(he)(he)开(kai)关(guan)(guan)管(guan)(guan)(guan)1构(gou)成(cheng)的(de)是(shi)(shi)比(bi)例开(kai)关(guan)(guan)电(dian)源。运(yun)(yun)(yun)(yun)放(fang)(fang)(fang)4和(he)(he)开(kai)关(guan)(guan)管(guan)(guan)(guan)2也(ye)同样。它(ta)的(de)开(kai)关(guan)(guan)频(pin)率不(bu)稳定。在(zai)运(yun)(yun)(yun)(yun)放(fang)(fang)(fang)1输(shu)出(chu)(chu)信号为(wei)(wei)正(zheng)相(xiang)(xiang)时(shi),运(yun)(yun)(yun)(yun)放(fang)(fang)(fang)3和(he)(he)开(kai)关(guan)(guan)管(guan)(guan)(guan)工(gong)作(zuo)(zuo)。这(zhei)时(shi)运(yun)(yun)(yun)(yun)放(fang)(fang)(fang)2输(shu)出(chu)(chu)的(de)是(shi)(shi)负(fu)相(xiang)(xiang)。这(zhei)时(shi)运(yun)(yun)(yun)(yun)放(fang)(fang)(fang)4的(de)正(zheng)输(shu)入端(duan)的(de)电(dian)位(恒(heng)为(wei)(wei)0)总比(bi)负(fu)输(shu)入端(duan)的(de)电(dian)位高,所以运(yun)(yun)(yun)(yun)放(fang)(fang)(fang)4输(shu)出(chu)(chu)恒(heng)为(wei)(wei)1,开(kai)关(guan)(guan)管(guan)(guan)(guan)关(guan)(guan)闭(bi)。在(zai)运(yun)(yun)(yun)(yun)放(fang)(fang)(fang)1输(shu)出(chu)(chu)为(wei)(wei)负(fu)相(xiang)(xiang)时(shi),则相(xiang)(xiang)反。这(zhei)就实(shi)(shi)现了两开(kai)关(guan)(guan)管(guan)(guan)(guan)交替工(gong)作(zuo)(zuo)。
当(dang)基(ji)准信(xin)(xin)号(hao)(hao)比(bi)检测(ce)(ce)信(xin)(xin)号(hao)(hao),也即是运放3或4的(de)(de)(de)负(fu)输(shu)入(ru)端(duan)(duan)的(de)(de)(de)信(xin)(xin)号(hao)(hao)比(bi)正输(shu)入(ru)端(duan)(duan)的(de)(de)(de)信(xin)(xin)号(hao)(hao)高一(yi)微小(xiao)值(zhi)时(shi),比(bi)较(jiao)器(qi)输(shu)出0,开(kai)关(guan)管(guan)开(kai),随之(zhi)检测(ce)(ce)信(xin)(xin)号(hao)(hao)迅(xun)速提高,当(dang)检测(ce)(ce)信(xin)(xin)号(hao)(hao)比(bi)基(ji)准信(xin)(xin)号(hao)(hao)高一(yi)微小(xiao)值(zhi)时(shi),比(bi)较(jiao)器(qi)输(shu)出1,开(kai)关(guan)管(guan)关(guan)。这里要注意的(de)(de)(de)是,在(zai)(zai)电路翻(fan)转时(shi)比(bi)较(jiao)器(qi)有个(ge)正反(fan)馈过程,这是迟滞比(bi)较(jiao)器(qi)的(de)(de)(de)特点(dian)。比(bi)如说在(zai)(zai)基(ji)准信(xin)(xin)号(hao)(hao)比(bi)检测(ce)(ce)信(xin)(xin)号(hao)(hao)低(di)的(de)(de)(de)前提下(xia),随着它们(men)(men)的(de)(de)(de)差值(zhi)不断地靠(kao)近(jin),在(zai)(zai)它们(men)(men)相(xiang)等的(de)(de)(de)瞬间(jian),基(ji)准信(xin)(xin)号(hao)(hao)马上比(bi)检测(ce)(ce)信(xin)(xin)号(hao)(hao)高出一(yi)定(ding)值(zhi)。这个(ge)“一(yi)定(ding)值(zhi)”影响开(kai)关(guan)频率。它越(yue)大频率越(yue)低(di)。这里选它为0.1~0.2V。
C3,C4的(de)作(zuo)用是为了(le)让频率(lv)较高的(de)开(kai)关续流(liu)电(dian)流(liu)通过,而对频率(lv)较低的(de)50Hz信(xin)号产(chan)生较大的(de)阻抗(kang)。C5由公式:50=算出。L一(yi)般为70H,制作(zuo)时最(zui)好测一(yi)下。这样C为0.15μ左右。R4与R3的(de)比值要严格(ge)等(deng)于0.5,大了(le)波(bo)形失真明显,小(xiao)(xiao)了(le)不(bu)(bu)能起振,但(dan)是宁可大一(yi)些,不(bu)(bu)可小(xiao)(xiao)。开(kai)关管的(de)最(zui)大电(dian)流(liu)为:
I==25A。
现有(you)的(de)(de)(de)(de)逆(ni)变器(qi)(qi),有(you)方波(bo)输(shu)出和(he)正弦(xian)波(bo)输(shu)出两(liang)种。方波(bo)输(shu)出的(de)(de)(de)(de)逆(ni)变器(qi)(qi)效率高,对于采用(yong)正弦(xian)波(bo)电(dian)源设计的(de)(de)(de)(de)电(dian)器(qi)(qi)来说,除少数电(dian)器(qi)(qi)不适(shi)(shi)用(yong)外大(da)多数电(dian)器(qi)(qi)都可(ke)适(shi)(shi)用(yong),正弦(xian)波(bo)输(shu)出的(de)(de)(de)(de)逆(ni)变器(qi)(qi)就没有(you)这方面的(de)(de)(de)(de)缺点,却(que)存在效率低的(de)(de)(de)(de)缺点,如何选(xuan)择这就需要根据(ju)自己的(de)(de)(de)(de)需求了。
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