逆变器工(gong)作原理(li)-工(gong)作原理(li)、结构、作用与原理(li)图详解-KIA MOS管(guan)
信息来源:本站 日期:2018-01-15
逆(ni)变(bian)(bian)(bian)器(qi)是一(yi)(yi)(yi)种由半(ban)(ban)导体(ti)器(qi)件组成的(de)(de)(de)电(dian)(dian)(dian)(dian)力(li)调(diao)整装置(zhi),主(zhu)(zhu)要用于把(ba)(ba)直流(liu)电(dian)(dian)(dian)(dian)力(li)转换(huan)成交流(liu)电(dian)(dian)(dian)(dian)力(li)。由升压(ya)回路(lu)(lu)(lu)以(yi)及逆(ni)变(bian)(bian)(bian)桥式回路(lu)(lu)(lu)构成。升压(ya)回路(lu)(lu)(lu)把(ba)(ba)太阳电(dian)(dian)(dian)(dian)池的(de)(de)(de)直流(liu)电(dian)(dian)(dian)(dian)压(ya)升压(ya)到(dao)逆(ni)变(bian)(bian)(bian)器(qi)输出(chu)控制所(suo)需(xu)的(de)(de)(de)直流(liu)电(dian)(dian)(dian)(dian)压(ya);逆(ni)变(bian)(bian)(bian)桥式回路(lu)(lu)(lu)则把(ba)(ba)升压(ya)后的(de)(de)(de)直流(liu)电(dian)(dian)(dian)(dian)压(ya)等价地转换(huan)成常用频(pin)率(lv)的(de)(de)(de)交流(liu)电(dian)(dian)(dian)(dian)压(ya)。逆(ni)变(bian)(bian)(bian)器(qi)主(zhu)(zhu)要由晶体(ti)管(guan)等开(kai)关(guan)(guan)元(yuan)(yuan)件构成,通过(guo)有规则地让开(kai)关(guan)(guan)元(yuan)(yuan)件重(zhong)复开(kai)-关(guan)(guan)(ON-OFF),由直流(liu)电(dian)(dian)(dian)(dian)变(bian)(bian)(bian)交流(liu)电(dian)(dian)(dian)(dian)输出(chu)。当然(ran)(ran),这样单纯(chun)地由开(kai)和关(guan)(guan)回路(lu)(lu)(lu)产生(sheng)的(de)(de)(de)逆(ni)变(bian)(bian)(bian)器(qi)输出(chu)波(bo)形并不(bu)实用。一(yi)(yi)(yi)般需(xu)要采用高频(pin)脉宽(kuan)调(diao)制,使(shi)靠近正弦波(bo)两(liang)端的(de)(de)(de)电(dian)(dian)(dian)(dian)压(ya)宽(kuan)度(du)(du)变(bian)(bian)(bian)狭,正弦波(bo)中(zhong)央的(de)(de)(de)电(dian)(dian)(dian)(dian)压(ya)宽(kuan)度(du)(du)变(bian)(bian)(bian)宽(kuan),并在半(ban)(ban)周期内(nei)始终让开(kai)关(guan)(guan)元(yuan)(yuan)件按(an)一(yi)(yi)(yi)定频(pin)率(lv)朝一(yi)(yi)(yi)方向动作,这样形成一(yi)(yi)(yi)个脉冲波(bo)列(拟正弦波(bo))。然(ran)(ran)后让脉冲波(bo)通过(guo)简单的(de)(de)(de)滤波(bo)器(qi)形成正弦波(bo)。
逆变(bian)器不仅具有直流电交流变(bian)换(huan)功能(neng)(neng),还具有最(zui)大限度地(di)发挥太阳电池性能(neng)(neng)的功能(neng)(neng)和系统(tong)故障保护功能(neng)(neng)。
1、自动运行(xing)和停机(ji)功(gong)能
早晨日出(chu)(chu)(chu)(chu)后(hou),太(tai)(tai)阳(yang)辐射强(qiang)度(du)逐渐增(zeng)强(qiang),太(tai)(tai)阳(yang)电(dian)池的(de)输(shu)(shu)(shu)出(chu)(chu)(chu)(chu)也(ye)随之增(zeng)大,当达到逆(ni)(ni)变(bian)器(qi)工(gong)作(zuo)所(suo)需的(de)输(shu)(shu)(shu)出(chu)(chu)(chu)(chu)功率后(hou),逆(ni)(ni)变(bian)器(qi)即自动(dong)开(kai)始运(yun)(yun)行(xing)。进入运(yun)(yun)行(xing)后(hou),逆(ni)(ni)变(bian)器(qi)便(bian)时时刻刻监视太(tai)(tai)阳(yang)电(dian)池组件的(de)输(shu)(shu)(shu)出(chu)(chu)(chu)(chu),只要太(tai)(tai)阳(yang)电(dian)池组件的(de)输(shu)(shu)(shu)出(chu)(chu)(chu)(chu)功率大于逆(ni)(ni)变(bian)器(qi)工(gong)作(zuo)所(suo)需的(de)输(shu)(shu)(shu)出(chu)(chu)(chu)(chu)功率,逆(ni)(ni)变(bian)器(qi)就持续运(yun)(yun)行(xing);直到日落停机,即使阴雨天(tian)逆(ni)(ni)变(bian)器(qi)也(ye)能(neng)运(yun)(yun)行(xing)。当太(tai)(tai)阳(yang)电(dian)池组件输(shu)(shu)(shu)出(chu)(chu)(chu)(chu)变(bian)小,逆(ni)(ni)变(bian)器(qi)输(shu)(shu)(shu)出(chu)(chu)(chu)(chu)接近0时,逆(ni)(ni)变(bian)器(qi)便(bian)形成待机状态。
2、最(zui)大功率(lv)跟(gen)踪(zong)控制功能(neng)
太阳电(dian)池(chi)组(zu)(zu)(zu)(zu)件(jian)的输出是(shi)(shi)随太阳辐射(she)强度和太阳电(dian)池(chi)组(zu)(zu)(zu)(zu)件(jian)自(zi)身(shen)温度(芯片温度)而变(bian)化(hua)(hua)的。另外由于太阳电(dian)池(chi)组(zu)(zu)(zu)(zu)件(jian)具有(you)电(dian)压随电(dian)流增大而下降(jiang)的特(te)性,因此(ci)存在能获取最(zui)(zui)大功(gong)(gong)率(lv)(lv)的最(zui)(zui)佳工作点。太阳辐射(she)强度是(shi)(shi)变(bian)化(hua)(hua)着的,显然最(zui)(zui)佳工作点也是(shi)(shi)在变(bian)化(hua)(hua)的。相对(dui)于这些变(bian)化(hua)(hua),始(shi)终让(rang)太阳电(dian)池(chi)组(zu)(zu)(zu)(zu)件(jian)的工作点处(chu)于最(zui)(zui)大功(gong)(gong)率(lv)(lv)点,系统(tong)始(shi)终从(cong)太阳电(dian)池(chi)组(zu)(zu)(zu)(zu)件(jian)获取最(zui)(zui)大功(gong)(gong)率(lv)(lv)输出,这种控制(zhi)就(jiu)(jiu)是(shi)(shi)最(zui)(zui)大功(gong)(gong)率(lv)(lv)跟(gen)(gen)踪(zong)控制(zhi)。太阳能发电(dian)系统(tong)用的逆变(bian)器的最(zui)(zui)大特(te)点就(jiu)(jiu)是(shi)(shi)包括了最(zui)(zui)大功(gong)(gong)率(lv)(lv)点跟(gen)(gen)踪(zong)这一功(gong)(gong)能。
1.直流电(dian)可(ke)以(yi)通过(guo)震荡电(dian)路(lu)变为(wei)交流电(dian)
2.得(de)到的交流电再通过(guo)线圈升压(这时得(de)到的是(shi)方形波的交流电)
3.对得(de)到(dao)的交流(liu)电(dian)进行(xing)整流(liu)得(de)到(dao)正弦波
AC-DC就(jiu)比较(jiao)简单(dan)(dan)了(le) 我们(men)知(zhi)道二极管有单(dan)(dan)向(xiang)导电性
可以用(yong)(yong)二极(ji)管的(de)这一(yi)特性连(lian)成一(yi)个(ge)(ge)电(dian)(dian)(dian)桥让一(yi)端(duan)始终是(shi)流(liu)(liu)(liu)入的(de) 另一(yi)端(duan)始终是(shi)流(liu)(liu)(liu)出的(de)这就得到(dao)了电(dian)(dian)(dian)压正弦变化的(de)直(zhi)流(liu)(liu)(liu)电(dian)(dian)(dian) 如果需要(yao)平滑的(de)直(zhi)流(liu)(liu)(liu)电(dian)(dian)(dian)还需要(yao)进行(xing)整流(liu)(liu)(liu) 简单的(de)方法(fa)就是(shi)连(lian)接(jie)一(yi)个(ge)(ge)电(dian)(dian)(dian)容Inverter是(shi)一(yi)种(zhong)DC to AC的(de)变压器,它其实与Adapter是(shi)一(yi)种(zhong)电(dian)(dian)(dian)压逆变的(de)过程(cheng)。Adapter是(shi)将(jiang)市电(dian)(dian)(dian)电(dian)(dian)(dian)网(wang)的(de)交(jiao)流(liu)(liu)(liu)电(dian)(dian)(dian)压转变为(wei)稳(wen)定的(de)12V直(zhi)流(liu)(liu)(liu)输出,而Inverter是(shi)将(jiang)Adapter输出的(de)12V直(zhi)流(liu)(liu)(liu)电(dian)(dian)(dian)压转变为(wei)高频的(de)高压交(jiao)流(liu)(liu)(liu)电(dian)(dian)(dian);两个(ge)(ge)部分同(tong)样都采用(yong)(yong)了目前用(yong)(yong)得比较多(duo)的(de)脉宽(kuan)调(diao)制(zhi)(zhi)(PWM)技术。其核心部分都是(shi)一(yi)个(ge)(ge)PWM集成控制(zhi)(zhi)器,Adapter用(yong)(yong)的(de)是(shi)UC3842,Inverter则(ze)采用(yong)(yong)TL5001芯片。TL5001的(de)工(gong)作电(dian)(dian)(dian)压范围(wei)3.6~40V,其内部设(she)有(you)一(yi)个(ge)(ge)误差(cha)放大(da)器,一(yi)个(ge)(ge)调(diao)节器、振荡器、有(you)死区(qu)控制(zhi)(zhi)的(de)PWM发生器、低(di)压保(bao)护回路及短路保(bao)护回路等。
输入接口部分:
输入部分有3个(ge)信号(hao),12V直流输入VIN、工(gong)作使能电压ENB及(ji)Panel电流控制(zhi)信号(hao)DIM。VIN由Adapter提(ti)供,ENB电压由主(zhu)板上的(de)MCU提(ti)供,其值(zhi)(zhi)为0或3V,当ENB=0时,Inverter不工(gong)作,而ENB=3V时,Inverter处(chu)于正常工(gong)作状态;而DIM电压由主(zhu)板提(ti)供,其变化(hua)范围在0~5V之间(jian),将不同的(de)DIM值(zhi)(zhi)反(fan)(fan)馈(kui)给PWM控制(zhi)器反(fan)(fan)馈(kui)端(duan),Inverter向负载提(ti)供的(de)电流也将不同,DIM值(zhi)(zhi)越(yue)小,Inverter输出(chu)的(de)电流就越(yue)大。
电压启动回路:
ENB为高电平时,输(shu)出高压去(qu)点亮Panel的背光灯灯管。
PWM控制器:
有以下几个功(gong)能组成:内(nei)部参考电压、误差放(fang)大(da)器(qi)、振(zhen)荡器(qi)和PWM、过(guo)压保护(hu)(hu)、欠压保护(hu)(hu)、短路保护(hu)(hu)、输出晶(jing)体管。
直流变换:
由MOS开关(guan)管和储能(neng)电(dian)(dian)感组(zu)成电(dian)(dian)压(ya)变换电(dian)(dian)路,输入(ru)的(de)脉冲经过推挽放(fang)大(da)(da)器放(fang)大(da)(da)后(hou)驱动MOS管做开关(guan)动作,使得(de)直流电(dian)(dian)压(ya)对电(dian)(dian)感进行充放(fang)电(dian)(dian),这(zhei)样电(dian)(dian)感的(de)另一端就能(neng)得(de)到交流电(dian)(dian)压(ya)。
LC振荡及输出回路:
保证灯管启动需要的1600V电(dian)压,并在灯管启动以后将电(dian)压降至800V。
输出电压反馈:
当负(fu)载工作时,反馈(kui)采(cai)样电(dian)压,起到稳定Inventer电(dian)压输出的作用。
其实你可(ke)以(yi)想(xiang)象一(yi)下了(le).都有(you)(you)那些电(dian)(dian)(dian)(dian)子(zi)元件需(xu)要(yao)正(zheng)负(fu)极,电(dian)(dian)(dian)(dian)阻(zu),电(dian)(dian)(dian)(dian)感(gan)一(yi)般(ban)不需(xu)要(yao).二极管(guan)一(yi)般(ban)坏(huai)的(de)(de)可(ke)能就(jiu)(jiu)是被击穿只要(yao)电(dian)(dian)(dian)(dian)压(ya)正(zheng)常一(yi)般(ban)是没有(you)(you)问(wen)题的(de)(de),三极管(guan)的(de)(de)话(hua)是不会导通(tong)的(de)(de).稳压(ya)管(guan)如果正(zheng)负(fu)接反(fan)的(de)(de)话(hua)就(jiu)(jiu)会损坏(huai)了(le),但一(yi)般(ban)有(you)(you)的(de)(de)电(dian)(dian)(dian)(dian)路加(jia)了(le)保护就(jiu)(jiu)是利用二极管(guan)的(de)(de)单(dan)向导通(tong)来(lai)保护.在就(jiu)(jiu)是电(dian)(dian)(dian)(dian)容(rong)了(le),电(dian)(dian)(dian)(dian)容(rong)里有(you)(you)正(zheng)负(fu)之分(fen)的(de)(de)就(jiu)(jiu)是电(dian)(dian)(dian)(dian)解电(dian)(dian)(dian)(dian)容(rong)了(le),如果正(zheng)负(fu)接反(fan)严重的(de)(de)话(hua)其外(wai)壳发生爆裂.
主(zhu)要元(yuan)件(jian)二极管.开(kai)关(guan)管振(zhen)荡变(bian)压器.取(qu)样.调宽管.还有振(zhen)荡回路(lu)电阻电容等参开(kai)关(guan)电路(lu)原理.
逆变(bian)器的(de)主功(gong)率(lv)元件(jian)的(de)选择至关(guan)重要,目前使用(yong)较(jiao)多的(de)功(gong)率(lv)元件(jian)有达林顿功(gong)率(lv)晶体(ti)管(guan)(guan)(BJT),功(gong)率(lv)场(chang)效应管(guan)(guan)(MOSFET),绝缘栅晶体(ti)管(guan)(guan)(IGBT)和可(ke)关(guan) 断晶闸管(guan)(guan)(GTO)等,在(zai)(zai)小(xiao)容量(liang)低压(ya)系统(tong)中(zhong)(zhong)(zhong)使用(yong)较(jiao)多的(de)器件(jian)为(wei)MOSFET,因(yin)为(wei)MOSFET具有较(jiao)低的(de)通(tong)态压(ya)降和较(jiao)高的(de)开关(guan)频率(lv),在(zai)(zai)高压(ya)大(da)(da)容量(liang)系统(tong)中(zhong)(zhong)(zhong)一般 均(jun)采用(yong)IGBT模块(kuai),这是因(yin)为(wei)MOSFET随着电(dian)压(ya)的(de)升高其通(tong)态电(dian)阻也随之增大(da)(da),而(er)IGBT在(zai)(zai)中(zhong)(zhong)(zhong)容量(liang)系统(tong)中(zhong)(zhong)(zhong)占有较(jiao)大(da)(da)的(de)优势(shi),而(er)在(zai)(zai)特大(da)(da)容量(liang)(100KVA以(yi) 上)系统(tong)中(zhong)(zhong)(zhong),一般均(jun)采用(yong)GTO作为(wei)功(gong)率(lv)元件(jian) .
大件(jian):场效应管或IGBT、变(bian)压器、电容、二极管、比较器以及(ji)3525之类的主控。交(jiao)(jiao)直交(jiao)(jiao)逆变(bian)还有整流滤波。
功率大(da)小和精度,关(guan)系着电路的复杂程度。
IGBT(绝缘(yuan)栅(zha)双(shuang)极(ji)晶(jing)体(ti)管)作为新(xin)型(xing)电(dian)(dian)力半(ban)导体(ti)场控自关断器件,集(ji)功率MOSFET的(de)高(gao)(gao)速性(xing)(xing)能与(yu)(yu)双(shuang)极(ji)性(xing)(xing)器件的(de)低电(dian)(dian)阻于一(yi)体(ti),具有(you)输入阻抗高(gao)(gao),电(dian)(dian)压(ya)控制(zhi)(zhi)功耗(hao)低,控制(zhi)(zhi)电(dian)(dian)路简单,耐高(gao)(gao)压(ya),承受(shou)电(dian)(dian)流(liu)大(da)等特性(xing)(xing),在各种电(dian)(dian)力变(bian)换(huan)中获得(de)极(ji)广泛的(de)应用。与(yu)(yu)此同时(shi),各大(da)半(ban)导体(ti)生产(chan)厂商不断开发(fa)IGBT的(de)高(gao)(gao)耐压(ya)、大(da)电(dian)(dian)流(liu)、高(gao)(gao)速、低饱和压(ya)降、高(gao)(gao)可靠(kao)性(xing)(xing)、低成本技术(shu),主要(yao)采用1um以下制(zhi)(zhi)作工艺,研制(zhi)(zhi)开发(fa)取得(de)一(yi)些新(xin)进展。
为通常(chang)使用的(de)单相输出的(de)全桥逆变主(zhu)电路,交流(liu)元件(jian)采用IGBT管Q11、Q12、Q13、Q14。并(bing)由PWM脉宽(kuan)调制控制IGBT管的(de)导通或截止。
当(dang)逆变(bian)(bian)(bian)(bian)器(qi)电(dian)路(lu)接(jie)上(shang)直流(liu)(liu)电(dian)源(yuan)后(hou),先(xian)由Q11、Q14导通,Q1、Q13截(jie)止,则电(dian)流(liu)(liu)由直流(liu)(liu)电(dian)源(yuan)正(zheng)(zheng)(zheng)极(ji)(ji)(ji)输出(chu),经(jing)Q11、L或(huo)感、变(bian)(bian)(bian)(bian)压(ya)(ya)器(qi)初级(ji)线(xian)(xian)圈图(tu)1-2,到Q14回(hui)到电(dian)源(yuan)负(fu)极(ji)(ji)(ji)。当(dang)Q11、Q14截(jie)止后(hou),Q12、Q13导通,电(dian)流(liu)(liu)从电(dian)源(yuan)正(zheng)(zheng)(zheng)极(ji)(ji)(ji)经(jing)Q13、变(bian)(bian)(bian)(bian)压(ya)(ya)器(qi)初级(ji)线(xian)(xian)圈2-1电(dian)感到Q12回(hui)到电(dian)源(yuan)负(fu)极(ji)(ji)(ji)。此时,在变(bian)(bian)(bian)(bian)压(ya)(ya)器(qi)初级(ji)线(xian)(xian)圈上(shang),已(yi)形(xing)成正(zheng)(zheng)(zheng)负(fu)交(jiao)变(bian)(bian)(bian)(bian)方波,利用高频PWM控制,两对(dui)IGBT管交(jiao)替重复,在变(bian)(bian)(bian)(bian)压(ya)(ya)器(qi)上(shang)产生交(jiao)流(liu)(liu)电(dian)压(ya)(ya)。由于LC交(jiao)流(liu)(liu)滤波器(qi)作用,使输出(chu)端形(xing)成正(zheng)(zheng)(zheng)弦波交(jiao)流(liu)(liu)电(dian)压(ya)(ya)。
当Q11、Q14关断时(shi),为了释放储存(cun)能量,在IGBT处并联二级管(guan)D11、D12,使(shi)能量返回(hui)到直流电源中去。
半控型逆(ni)变(bian)器(qi)采(cai)用(yong)(yong)晶闸(zha)管元(yuan)件。Th1、Th2为交(jiao)替(ti)工作的(de)(de)晶闸(zha)管,设Th1先触(chu)发导通,则(ze)电(dian)(dian)(dian)流(liu)(liu)通过(guo)变(bian)压(ya)器(qi)流(liu)(liu)经(jing)Th1,同时由于(yu)变(bian)压(ya)器(qi)的(de)(de)感(gan)应作用(yong)(yong),换向电(dian)(dian)(dian)容器(qi)C被充电(dian)(dian)(dian)到大的(de)(de)2倍的(de)(de)电(dian)(dian)(dian)源(yuan)电(dian)(dian)(dian)压(ya)。按(an)着Th2被触(chu)发导通,因Th2的(de)(de)阳极加反(fan)向偏压(ya),Th1截(jie)止,返(fan)回阻断(duan)状(zhuang)态。这样,Th1与Th2换流(liu)(liu),然(ran)后(hou)电(dian)(dian)(dian)容器(qi)C又反(fan)极性(xing)充电(dian)(dian)(dian)。如此(ci)交(jiao)替(ti)触(chu)发晶闸(zha)管,电(dian)(dian)(dian)流(liu)(liu)交(jiao)替(ti)流(liu)(liu)向变(bian)压(ya)器(qi)的(de)(de)初(chu)级,在变(bian)压(ya)器(qi)的(de)(de)次(ci)级得到交(jiao)流(liu)(liu)电(dian)(dian)(dian)。
在电(dian)(dian)路中,电(dian)(dian)感(gan)L可(ke)以限制换(huan)向(xiang)电(dian)(dian)容C的(de)放电(dian)(dian)电(dian)(dian)流,延长放电(dian)(dian)时(shi)间(jian),保证(zheng)电(dian)(dian)路关断(duan)(duan)时(shi)间(jian)大于(yu)晶闸管的(de)关断(duan)(duan)时(shi)间(jian),而不需容量(liang)(liang)很大的(de)电(dian)(dian)容器(qi)。D1和(he)D2是2只反馈二(er)极管,可(ke)将电(dian)(dian)感(gan)L中的(de)能(neng)量(liang)(liang)释放,将换(huan)向(xiang)剩(sheng)余(yu)的(de)能(neng)量(liang)(liang)送回电(dian)(dian)源(yuan),完成能(neng)量(liang)(liang)的(de)反馈作(zuo)用。
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