mos逆变(bian)器-太阳能逆变(bian)器的(de)原理(li)及(ji)架构详(xiang)解(jie)分析-KIA MOS管
信息(xi)来源：本站 日(ri)期：2018-03-14
发展逆变器(qi)(qi)技术是(shi)太阳能(neng)应用提出的要求，本文介绍(shao)(shao)了(le)太阳能(neng)逆变器(qi)(qi)的原理(li)及架构(gou)，着重介绍(shao)(shao)了(le)IGBT和MOSFET技术，实现智能(neng)控制是(shi)发展太阳能(neng)逆变器(qi)(qi)技术的关键(jian)。
通(tong)(tong)过(guo)太(tai)阳(yang)能(neng)光(guang)(guang)伏(fu)技术将(jiang)太(tai)阳(yang)辐射转(zhuan)换成(cheng)电能(neng)是(shi)现在市(shi)面上(shang)最有效(xiao)也是(shi)最具发展潜力的(de)可再生(sheng)能(neng)源技术。现在，普通(tong)(tong)太(tai)阳(yang)能(neng)光(guang)(guang)伏(fu)系统(tong)都是(shi)由许多紧密相连的(de)太(tai)阳(yang)能(neng)电池板组(zu)(zu)成(cheng)。这些电池板先分组(zu)(zu)串联(lian)，再将(jiang)不同的(de)串联(lian)电池组(zu)(zu)并联(lian)起来形(xing)成(cheng)电池阵(zhen)列。
目前我国(guo)(guo)光(guang)伏(fu)(fu)发电(dian)(dian)(dian)系(xi)统(tong)(tong)主要是直(zhi)流(liu)系(xi)统(tong)(tong)，即将(jiang)太阳电(dian)(dian)(dian)池发出的(de)电(dian)(dian)(dian)能给蓄电(dian)(dian)(dian)池充电(dian)(dian)(dian)，而蓄电(dian)(dian)(dian)池直(zhi)接(jie)给负载(zai)供(gong)电(dian)(dian)(dian)，如我国(guo)(guo)西北地区使用(yong)较(jiao)多(duo)的(de)太阳能户(hu)用(yong)照明系(xi)统(tong)(tong)以及远离电(dian)(dian)(dian)网的(de)微波站供(gong)电(dian)(dian)(dian)系(xi)统(tong)(tong)均为(wei)直(zhi)流(liu)系(xi)统(tong)(tong)。此类系(xi)统(tong)(tong)结构简单，成(cheng)本低廉(lian)，但由(you)于负载(zai)直(zhi)流(liu)电(dian)(dian)(dian)压的(de)不同（如12Ｖ、24Ｖ、48Ｖ等），很(hen)(hen)难(nan)实(shi)现(xian)系(xi)统(tong)(tong)的(de)标准(zhun)化和兼容性(xing)，特别是民用(yong)电(dian)(dian)(dian)力，由(you)于大多(duo)为(wei)交流(liu)负载(zai)，以直(zhi)流(liu)电(dian)(dian)(dian)力供(gong)电(dian)(dian)(dian)的(de)光(guang)伏(fu)(fu)电(dian)(dian)(dian)源很(hen)(hen)难(nan)作为(wei)商品进入市场。光(guang)伏(fu)(fu)发电(dian)(dian)(dian)最终将(jiang)实(shi)现(xian)并网运行，这就必须采用(yong)成(cheng)熟的(de)市场模式，今后交流(liu)光(guang)伏(fu)(fu)发电(dian)(dian)(dian)系(xi)统(tong)(tong)必将(jiang)成(cheng)为(wei)光(guang)伏(fu)(fu)发电(dian)(dian)(dian)的(de)主流(liu)。
太阳(yang)能(neng)(neng)逆(ni)变器(qi)(qi)(qi)是一(yi)(yi)种(zhong)功(gong)率(lv)电(dian)(dian)(dian)子电(dian)(dian)(dian)路，能(neng)(neng)把太阳(yang)能(neng)(neng)电(dian)(dian)(dian)池(chi)板(ban)的(de)(de)(de)直流(liu)(liu)电(dian)(dian)(dian)压转换(huan)为交流(liu)(liu)电(dian)(dian)(dian)压来(lai)驱动(dong)家用电(dian)(dian)(dian)器(qi)(qi)(qi)、照明及电(dian)(dian)(dian)机工具(ju)等交流(liu)(liu)负载(zai)，是整个(ge)(ge)太阳(yang)能(neng)(neng)发电(dian)(dian)(dian)系(xi)统(tong)的(de)(de)(de)关键组件。逆(ni)变器(qi)(qi)(qi)有两(liang)个(ge)(ge)基本(ben)功(gong)能(neng)(neng)：一(yi)(yi)方面是为完成(cheng)DC/AC转换(huan)的(de)(de)(de)电(dian)(dian)(dian)流(liu)(liu)连接到电(dian)(dian)(dian)网，另一(yi)(yi)方面是找出最(zui)佳的(de)(de)(de)操作点(dian)以(yi)优化太阳(yang)能(neng)(neng)光伏系(xi)统(tong)的(de)(de)(de)效率(lv)。对于特定的(de)(de)(de)太阳(yang)光辐(fu)射、温度及电(dian)(dian)(dian)池(chi)类型，太阳(yang)能(neng)(neng)光伏系(xi)统(tong)都相应有唯(wei)一(yi)(yi)的(de)(de)(de)最(zui)佳电(dian)(dian)(dian)压及电(dian)(dian)(dian)流(liu)(liu)，从而使光伏系(xi)统(tong)产生最(zui)大的(de)(de)(de)能(neng)(neng)量。因此(ci)，在太阳(yang)能(neng)(neng)应用中(zhong)对逆(ni)变器(qi)(qi)(qi)必(bi)须满足以(yi)下基本(ben)要求：
1.要(yao)求具(ju)有(you)较高(gao)的效(xiao)(xiao)率(lv)。由于目前太阳电(dian)池的价(jia)格偏高(gao)，为了最大(da)限度地利用(yong)太阳电(dian)池，提高(gao)系统(tong)效(xiao)(xiao)率(lv)，必须设法提高(gao)逆变器的效(xiao)(xiao)率(lv)。
2.要(yao)求具有较高的可靠性。目(mu)前光伏发电(dian)(dian)系统(tong)主要(yao)用于边远地区，许多(duo)电(dian)(dian)站无人(ren)值守(shou)和维护，这就要(yao)求逆变(bian)器具有合理的电(dian)(dian)路结(jie)构，严(yan)格的元器件(jian)筛选，并要(yao)求逆变(bian)器具备各种保护功能，如输入直流极(ji)性接反保护，交流输出(chu)短路保护，过(guo)热、过(guo)载保护等。
3.要求直流输入电(dian)(dian)(dian)(dian)(dian)(dian)压(ya)(ya)(ya)有较(jiao)宽的(de)(de)适应范围，由于(yu)太阳电(dian)(dian)(dian)(dian)(dian)(dian)池(chi)的(de)(de)端(duan)电(dian)(dian)(dian)(dian)(dian)(dian)压(ya)(ya)(ya)随(sui)负载和日照强度而变化，蓄(xu)电(dian)(dian)(dian)(dian)(dian)(dian)池(chi)虽然对(dui)太阳电(dian)(dian)(dian)(dian)(dian)(dian)池(chi)的(de)(de)电(dian)(dian)(dian)(dian)(dian)(dian)压(ya)(ya)(ya)具有重要作用，但(dan)由于(yu)蓄(xu)电(dian)(dian)(dian)(dian)(dian)(dian)池(chi)的(de)(de)电(dian)(dian)(dian)(dian)(dian)(dian)压(ya)(ya)(ya)随(sui)蓄(xu)电(dian)(dian)(dian)(dian)(dian)(dian)池(chi)剩(sheng)余容量和内阻的(de)(de)变化而波动，特别是当蓄(xu)电(dian)(dian)(dian)(dian)(dian)(dian)池(chi)老化时其(qi)(qi)端(duan)电(dian)(dian)(dian)(dian)(dian)(dian)压(ya)(ya)(ya)的(de)(de)变化范围很大，如１２Ｖ蓄(xu)电(dian)(dian)(dian)(dian)(dian)(dian)池(chi)，其(qi)(qi)端(duan)电(dian)(dian)(dian)(dian)(dian)(dian)压(ya)(ya)(ya)可在(zai)１０Ｖ～１６Ｖ之间变化，这就(jiu)要求逆变器必须在(zai)较(jiao)大的(de)(de)直流输入电(dian)(dian)(dian)(dian)(dian)(dian)压(ya)(ya)(ya)范围内保证正常(chang)工作，并(bing)保证交流输出电(dian)(dian)(dian)(dian)(dian)(dian)压(ya)(ya)(ya)的(de)(de)稳定。
4.在中、大容(rong)量(liang)的(de)(de)光伏(fu)发电(dian)系统中，逆变(bian)电(dian)源的(de)(de)输出(chu)应(ying)为失真度较(jiao)小的(de)(de)正弦波(bo)。这(zhei)是(shi)由于在中、大容(rong)量(liang)系统中，若采用方波(bo)供电(dian)，则输出(chu)将含有(you)较(jiao)多的(de)(de)谐(xie)波(bo)分量(liang)，高次(ci)谐(xie)波(bo)将产生附加(jia)损耗(hao)，许多光伏(fu)发电(dian)系统的(de)(de)负载为通信或仪表(biao)设(she)备(bei)，这(zhei)些(xie)设(she)备(bei)对(dui)电(dian)网(wang)品质(zhi)有(you)较(jiao)高的(de)(de)要(yao)(yao)求(qiu)，当中、大容(rong)量(liang)的(de)(de)光伏(fu)发电(dian)系统并网(wang)运(yun)行时，为避免(mian)与公共电(dian)网(wang)的(de)(de)电(dian)力污染，也(ye)要(yao)(yao)求(qiu)逆变(bian)器输出(chu)正弦波(bo)电(dian)流。
通常把(ba)(ba)交(jiao)流(liu)(liu)(liu)(liu)电(dian)能(neng)(neng)变(bian)(bian)(bian)(bian)(bian)换成直(zhi)(zhi)流(liu)(liu)(liu)(liu)电(dian)能(neng)(neng)的(de)(de)(de)过(guo)程称(cheng)(cheng)之为(wei)整流(liu)(liu)(liu)(liu)，相(xiang)控(kong)整流(liu)(liu)(liu)(liu)是最常见(jian)的(de)(de)(de)交(jiao)-直(zhi)(zhi)流(liu)(liu)(liu)(liu)变(bian)(bian)(bian)(bian)(bian)换过(guo)程；而(er)把(ba)(ba)直(zhi)(zhi)流(liu)(liu)(liu)(liu)电(dian)能(neng)(neng)变(bian)(bian)(bian)(bian)(bian)换成交(jiao)流(liu)(liu)(liu)(liu)电(dian)能(neng)(neng)的(de)(de)(de)过(guo)程称(cheng)(cheng)之为(wei)逆(ni)(ni)变(bian)(bian)(bian)(bian)(bian)，它是整流(liu)(liu)(liu)(liu)的(de)(de)(de)逆(ni)(ni)过(guo)程。在逆(ni)(ni)变(bian)(bian)(bian)(bian)(bian)电(dian)路中，按照负载(zai)性质(zhi)的(de)(de)(de)不同(tong)，逆(ni)(ni)变(bian)(bian)(bian)(bian)(bian)分(fen)为(wei)有源(yuan)逆(ni)(ni)变(bian)(bian)(bian)(bian)(bian)和(he)无源(yuan)逆(ni)(ni)变(bian)(bian)(bian)(bian)(bian)。如(ru)果把(ba)(ba)该电(dian)路的(de)(de)(de)交(jiao)流(liu)(liu)(liu)(liu)侧接到交(jiao)流(liu)(liu)(liu)(liu)电(dian)源(yuan)上，把(ba)(ba)直(zhi)(zhi)流(liu)(liu)(liu)(liu)电(dian)能(neng)(neng)经过(guo)直(zhi)(zhi)-交(jiao)流(liu)(liu)(liu)(liu)变(bian)(bian)(bian)(bian)(bian)换，逆(ni)(ni)变(bian)(bian)(bian)(bian)(bian)成与交(jiao)流(liu)(liu)(liu)(liu)电(dian)源(yuan)同(tong)频率的(de)(de)(de)交(jiao)流(liu)(liu)(liu)(liu)电(dian)返送到电(dian)网上去(qu)，称(cheng)(cheng)作有源(yuan)逆(ni)(ni)变(bian)(bian)(bian)(bian)(bian)。相(xiang)应(ying)的(de)(de)(de)装置称(cheng)(cheng)为(wei)有源(yuan)逆(ni)(ni)变(bian)(bian)(bian)(bian)(bian)器，控(kong)制角大于90°的(de)(de)(de)相(xiang)控(kong)整流(liu)(liu)(liu)(liu)器为(wei)常见(jian)的(de)(de)(de)有源(yuan)逆(ni)(ni)变(bian)(bian)(bian)(bian)(bian)器。而(er)把(ba)(ba)直(zhi)(zhi)流(liu)(liu)(liu)(liu)电(dian)能(neng)(neng)变(bian)(bian)(bian)(bian)(bian)换为(wei)交(jiao)流(liu)(liu)(liu)(liu)电(dian)能(neng)(neng)，直(zhi)(zhi)接向(xiang)非电(dian)源(yuan)负载(zai)供(gong)电(dian)的(de)(de)(de)电(dian)路，称(cheng)(cheng)之为(wei)无源(yuan)逆(ni)(ni)变(bian)(bian)(bian)(bian)(bian)电(dian)路，又称(cheng)(cheng)为(wei)变(bian)(bian)(bian)(bian)(bian)频器。
逆(ni)(ni)变(bian)器(qi)(qi)类型(xing)(xing)有(you)它励(li)逆(ni)(ni)变(bian)器(qi)(qi)、自励(li)逆(ni)(ni)变(bian)器(qi)(qi)、脉(mai)(mai)宽调制(zhi)(zhi)(zhi)（PWM）型(xing)(xing)逆(ni)(ni)变(bian)器(qi)(qi)。其中(zhong)他励(li)逆(ni)(ni)变(bian)器(qi)(qi)需要(yao)(yao)外部交流(liu)(liu)(liu)电(dian)压(ya)源(yuan)，给晶闸管提供(gong)整(zheng)流(liu)(liu)(liu)电(dian)压(ya)。他励(li)逆(ni)(ni)变(bian)器(qi)(qi)主要(yao)(yao)应用(yong)在大功率并网情况下；对于(yu)(yu)功率低于(yu)(yu)1MW 的(de)(de)(de)(de)光伏(fu)发电(dian)系统(tong)，主要(yao)(yao)采用(yong)自励(li)逆(ni)(ni)变(bian)器(qi)(qi)方式(shi)。自励(li)逆(ni)(ni)变(bian)器(qi)(qi)不(bu)需要(yao)(yao)外部交流(liu)(liu)(liu)电(dian)压(ya)源(yuan)，整(zheng)流(liu)(liu)(liu)电(dian)压(ya)由逆(ni)(ni)变(bian)器(qi)(qi)的(de)(de)(de)(de)一(yi)部分(fen)储能元件（比如电(dian)容(rong)）来提供(gong)或者(zhe)通(tong)过增加(jia)待关断整(zheng)流(liu)(liu)(liu)阀（像(xiang)MOSFET 或IGBT）的(de)(de)(de)(de)电(dian)阻(zu)值来实现。输出(chu)电(dian)压(ya)被脉(mai)(mai)冲(chong)调制(zhi)(zhi)(zhi)的(de)(de)(de)(de)自励(li)逆(ni)(ni)变(bian)器(qi)(qi)被称为脉(mai)(mai)冲(chong)逆(ni)(ni)变(bian)器(qi)(qi)。这种逆(ni)(ni)变(bian)器(qi)(qi)通(tong)过增加(jia)周(zhou)期内(nei)脉(mai)(mai)冲(chong)的(de)(de)(de)(de)切(qie)换次(ci)数，来降低电(dian)压(ya)、电(dian)流(liu)(liu)(liu)的(de)(de)(de)(de)谐波(bo)含量；谐波(bo)含量与脉(mai)(mai)冲(chong)切(qie)换次(ci)数呈正比。目前，并网逆(ni)(ni)变(bian)器(qi)(qi)的(de)(de)(de)(de)输出(chu)控(kong)(kong)制(zhi)(zhi)(zhi)模(mo)(mo)式(shi)主要(yao)(yao)有(you)两种：电(dian)压(ya)型(xing)(xing)控(kong)(kong)制(zhi)(zhi)(zhi)模(mo)(mo)式(shi)和电(dian)流(liu)(liu)(liu)型(xing)(xing)控(kong)(kong)制(zhi)(zhi)(zhi)模(mo)(mo)式(shi)。电(dian)压(ya)型(xing)(xing)控(kong)(kong)制(zhi)(zhi)(zhi)模(mo)(mo)式(shi)的(de)(de)(de)(de)原理是以输出(chu)电(dian)压(ya)作为受(shou)控(kong)(kong)量，系统(tong)输出(chu)和电(dian)网电(dian)压(ya)同(tong)频(pin)同(tong)相的(de)(de)(de)(de)电(dian)压(ya)信号(hao)，整(zheng)个(ge)系统(tong)相当(dang)于(yu)(yu)一(yi)个(ge)内(nei)阻(zu)很小的(de)(de)(de)(de)受(shou)控(kong)(kong)电(dian)压(ya)源(yuan)；电(dian)流(liu)(liu)(liu)型(xing)(xing)控(kong)(kong)制(zhi)(zhi)(zhi)模(mo)(mo)式(shi)的(de)(de)(de)(de)原理则是以输出(chu)电(dian)感(gan)电(dian)流(liu)(liu)(liu)作为受(shou)控(kong)(kong)目标(biao)，系统(tong)输出(chu)和电(dian)网电(dian)压(ya)同(tong)频(pin)同(tong)相的(de)(de)(de)(de)电(dian)流(liu)(liu)(liu)信号(hao)，整(zheng)个(ge)系统(tong)相当(dang)于(yu)(yu)一(yi)个(ge)内(nei)阻(zu)较大的(de)(de)(de)(de)受(shou)控(kong)(kong)电(dian)流(liu)(liu)(liu)源(yuan)。
目前(qian)，太阳能逆(ni)变(bian)器(qi)已有多(duo)种拓扑结构，最常见的(de)是用于(yu)单(dan)相的(de)半(ban)桥(qiao)、全桥(qiao)和Heric（Sunways专利）逆(ni)变(bian)器(qi)，以及用于(yu)三相的(de)六脉(mai)冲桥(qiao)和中(zhong)点钳(qian)位(wei)（NPC）逆(ni)变(bian)器(qi)。太阳能逆(ni)变(bian)器(qi)的(de)典型架构一般采用四个开关的(de)全桥(qiao)拓扑，如图(tu)1所示(shi)。
在(zai)(zai)图(tu)1中， Q1 和(he)Q3被指定为高压(ya)侧IGBT，Q2 和(he)Q4 则(ze)是低(di)压(ya)侧 IGBT。该(gai)逆变(bian)器(qi)用(yong)(yong)(yong)于(yu)在(zai)(zai)其目标市(shi)场的(de)频(pin)(pin)率(lv)和(he)电(dian)(dian)压(ya)条件下(xia)，产生单相位正弦电(dian)(dian)压(ya)波(bo)形。有些(xie)逆变(bian)器(qi)用(yong)(yong)(yong)于(yu)连接净计量效(xiao)益(yi)电(dian)(dian)网的(de)住宅安装，这就是其中一个目标应(ying)用(yong)(yong)(yong)市(shi)场，此(ci)项应(ying)用(yong)(yong)(yong)要(yao)求逆变(bian)器(qi)提(ti)供低(di)谐(xie)(xie)波(bo)交流正弦电(dian)(dian)压(ya)，让力(li)可(ke)注入电(dian)(dian)网中。 实(shi)质上(shang)，为保持谐(xie)(xie)波(bo)分量低(di)和(he)功(gong)率(lv)损(sun)耗(hao)(hao)最(zui)(zui)小，逆变(bian)器(qi)的(de)高压(ya)端(duan)IGBT采用(yong)(yong)(yong)脉宽调(diao)制（PWM），低(di)压(ya)端(duan)IGBT则(ze)以60Hz频(pin)(pin)率(lv)变(bian)换电(dian)(dian)流方(fang)向。通过(guo)让高压(ya)端(duan) IGBT使用(yong)(yong)(yong)20kHz或20kHz以上(shang)的(de)PWM频(pin)(pin)率(lv)和(he)50/60Hz调(diao)制方(fang)案，输出电(dian)(dian)感L1和(he)L2在(zai)(zai)实(shi)例中可(ke)以做(zuo)得很小，并且照样能(neng)对(dui)谐(xie)(xie)波(bo)分量进行高效(xiao)滤波(bo)。与快(kuai)速和(he)标准速度(du)的(de)平面器(qi)件相比，开(kai)关速度(du)为20kHz的(de)超快(kuai)速沟(gou)道型(xing)IGBT可(ke)以提(ti)供最(zui)(zui)低(di)的(de)总导通损(sun)耗(hao)(hao)和(he)开(kai)关功(gong)率(lv)损(sun)耗(hao)(hao)。同样，对(dui)于(yu)低(di)压(ya)端(duan)开(kai)关电(dian)(dian)路，工作(zuo)在(zai)(zai)60Hz的(de)标准速度(du)IGBT可(ke)以提(ti)供最(zui)(zui)低(di)的(de)功(gong)率(lv)损(sun)耗(hao)(hao)。
这个设计中的(de)(de)(de)(de)(de)开关(guan)技(ji)术具有(you)如下优(you)势：通过(guo)允许(xu)高压(ya)(ya)端和(he)低压(ya)(ya)端IGBT独(du)立优(you)化实现很高的(de)(de)(de)(de)(de)效(xiao)率；高压(ya)(ya)端、同(tong)封装的(de)(de)(de)(de)(de)软(ruan)恢(hui)(hui)复(fu)二极管没有(you)续流时间(jian)(jian)，从而消除了不(bu)(bu)必要的(de)(de)(de)(de)(de)开关(guan)损耗(hao)；低压(ya)(ya)端IGBT的(de)(de)(de)(de)(de)开关(guan)频率只有(you)60Hz，因(yin)此(ci)导通损耗(hao)是(shi)这些IGBT的(de)(de)(de)(de)(de)主(zhu)要因(yin)素；没有(you)交叉导通，因(yin)为任(ren)何时间(jian)(jian)点的(de)(de)(de)(de)(de)开关(guan)都发(fa)生在对(dui)角(jiao)的(de)(de)(de)(de)(de)两个器(qi)件(jian)上（Q1和(he)Q4或Q2和(he)Q3）；不(bu)(bu)存(cun)在总线直通的(de)(de)(de)(de)(de)可能性，因(yin)为桥(qiao)的(de)(de)(de)(de)(de)同(tong)一边上的(de)(de)(de)(de)(de)IGBT永远(yuan)不(bu)(bu)可能以互补(bu)方(fang)式(shi)开关(guan)；跨接低压(ya)(ya)端IGBT的(de)(de)(de)(de)(de)同(tong)封装、超快速、软(ruan)恢(hui)(hui)复(fu)二极管经过(guo)优(you)化可以使续流和(he)反(fan)向恢(hui)(hui)复(fu)期(qi)间(jian)(jian)的(de)(de)(de)(de)(de)损耗(hao)达(da)到最小(xiao)。
1.直流电(dian)可以通过(guo)震(zhen)荡电(dian)路(lu)变(bian)为交流电(dian)
2.得到的交(jiao)流(liu)电(dian)(dian)再通过线(xian)圈(quan)升压(ya)（这时(shi)得到的是方形(xing)波(bo)的交(jiao)流(liu)电(dian)(dian)）
3.对得到的(de)交流电进行(xing)整流得到正(zheng)弦波
AC-DC就(jiu)比较简单(dan)(dan)了(le)(le)我们知道(dao)二(er)极管有(you)单(dan)(dan)向导电(dian)性(xing)可(ke)以用二(er)极管的(de)这一特性(xing)连成一个(ge)电(dian)桥(qiao)让一端(duan)(duan)始终是流(liu)入的(de)另一端(duan)(duan)始终是流(liu)出(chu)的(de)这就(jiu)得到(dao)了(le)(le)电(dian)压正弦变化的(de)直(zhi)流(liu)电(dian) 如(ru)果需(xu)要平滑的(de)直(zhi)流(liu)电(dian)还需(xu)要进行整流(liu) 简单(dan)(dan)的(de)方法就(jiu)是连接(jie)一个(ge)电(dian)容(rong)
Inverter是一(yi)(yi)种(zhong)DCtoAC的(de)(de)变(bian)压器(qi)，它其(qi)实与Adapter是一(yi)(yi)种(zhong)电(dian)压逆变(bian)的(de)(de)过程。Adapter是将市(shi)电(dian)电(dian)网的(de)(de)交(jiao)流(liu)(liu)电(dian)压转(zhuan)变(bian)为稳定的(de)(de)12V直流(liu)(liu)输出，而Inverter是将 Adapter输出的(de)(de)12V直流(liu)(liu)电(dian)压转(zhuan)变(bian)为高频的(de)(de)高压交(jiao)流(liu)(liu)电(dian)；两个(ge)部分同样都采用了目前用得比(bi)较多的(de)(de)脉宽调制（PWM）技术。其(qi)核心部分都是一(yi)(yi)个(ge)PWM集 成控制器(qi)，Adapter用的(de)(de)是UC3842，I
nverter则采用TL5001芯片。TL5001的工作电(dian)压范围3.6～40V，其(qi)内部设有一(yi)个(ge)误差放大器，一(yi)个(ge)调(diao)节器、振荡器、有死区控(kong)制的PWM发生(sheng)器、低(di)压保(bao)护(hu)回路及短路保(bao)护(hu)回路等。
以下将对Inverter的工(gong)作原理(li)进(jin)行简(jian)要介(jie)绍：
输入接口部分：
输 入部分有(you)3个信号(hao)，12V直流(liu)输入VIN、工作(zuo)使能电(dian)压ENB及Panel电(dian)流(liu)控制信号(hao)DIM。VIN由Adapter提供，ENB电(dian)压由主板上的(de)(de)MCU 提供，其值为0或(huo)3V，当ENB=0时(shi)，Inverter不工作(zuo)，而(er)ENB=3V时(shi)，Inverter处于正常工作(zuo)状(zhuang)态；而(er)DIM电(dian)压由主板提供，其变化 范围在0～5V之间，将不同(tong)的(de)(de)DIM值反(fan)馈(kui)给(ji)PWM控制器反(fan)馈(kui)端(duan)，Inverter向负载提供的(de)(de)电(dian)流(liu)也(ye)将不同(tong)，DIM值越小，Inverter输出的(de)(de)电(dian)流(liu) 就(jiu)越大(da)。
电压启动回路：
ENB为高(gao)电平时，输出高(gao)压去点亮Panel的(de)背光灯灯管(guan)。
PWM控制器：
有(you)以下几个功能组(zu)成：内部参(can)考电压、误差放大器、振荡器和PWM、过压保(bao)(bao)护、欠压保(bao)(bao)护、短(duan)路保(bao)(bao)护、输出(chu)晶体管。
直流变换：
由MOS开(kai)关管(guan)和(he)储能电(dian)(dian)感组成(cheng)电(dian)(dian)压(ya)变(bian)换(huan)电(dian)(dian)路，输入的脉冲经过(guo)推挽放(fang)大器放(fang)大后驱动MOS管(guan)做开(kai)关动作，使(shi)得直(zhi)流(liu)电(dian)(dian)压(ya)对电(dian)(dian)感进行充(chong)放(fang)电(dian)(dian)，这样电(dian)(dian)感的另一(yi)端(duan)就能得到交流(liu)电(dian)(dian)压(ya)。
LC振荡及输出回路：
保证灯(deng)管启动需要(yao)的1600V电(dian)压(ya)，并(bing)在灯(deng)管启动以后将电(dian)压(ya)降至800V。
输出电压反馈：
当负载工作(zuo)时，反(fan)馈采(cai)样电(dian)压，起(qi)到(dao)稳定Inventer电(dian)压输出的(de)作(zuo)用。
其(qi)实你可以想象(xiang)一(yi)下了(le)(le)(le).都有那些电(dian)子元件需要(yao)(yao)正(zheng)(zheng)负(fu)极(ji),电(dian)阻,电(dian)感(gan)一(yi)般(ban)(ban)不需要(yao)(yao).二极(ji)管(guan)一(yi)般(ban)(ban)坏的(de)可能(neng)就(jiu)是(shi)(shi)(shi)被击穿只要(yao)(yao)电(dian)压(ya)正(zheng)(zheng)常(chang)一(yi)般(ban)(ban)是(shi)(shi)(shi)没有问题的(de),三(san)极(ji)管(guan)的(de)话是(shi)(shi)(shi)不会导(dao)通(tong)的(de).稳压(ya)管(guan)如果(guo)(guo)正(zheng)(zheng)负(fu)接(jie)反(fan)的(de)话就(jiu)会损(sun)坏了(le)(le)(le),但一(yi)般(ban)(ban)有的(de)电(dian)路(lu)加(jia)了(le)(le)(le)保(bao)护就(jiu)是(shi)(shi)(shi)利用二极(ji)管(guan)的(de)单向导(dao)通(tong)来保(bao)护.在就(jiu)是(shi)(shi)(shi)电(dian)容(rong)了(le)(le)(le),电(dian)容(rong)里有正(zheng)(zheng)负(fu)之分的(de)就(jiu)是(shi)(shi)(shi)电(dian)解电(dian)容(rong)了(le)(le)(le), 如果(guo)(guo)正(zheng)(zheng)负(fu)接(jie)反(fan)严重的(de)话其(qi)外壳(qiao)发生爆裂.
主要(yao)元件二极管.开(kai)关(guan)管振荡变压器.取样.调宽(kuan)管.还有振荡回路电阻(zu)电容等参开(kai)关(guan)电路原理.
逆变器(qi)(qi)的(de)(de)主(zhu)功率(lv)(lv)元件(jian)(jian)的(de)(de)选择至关重要，目前使用较(jiao)(jiao)多(duo)的(de)(de)功率(lv)(lv)元件(jian)(jian)有达林顿功率(lv)(lv)晶体管（BJT），功率(lv)(lv)场效应管（MOSFET），绝缘栅(zha)晶体管（IGBT）和可关断(duan)晶闸(zha)管（GTO）等，在(zai)(zai)小容量低压(ya)系(xi)(xi)统中(zhong)(zhong)使用较(jiao)(jiao)多(duo)的(de)(de)器(qi)(qi)件(jian)(jian)为MOSFET，因为MOSFET具有较(jiao)(jiao)低的(de)(de)通(tong)态(tai)压(ya)降(jiang)和较(jiao)(jiao)高的(de)(de)开关频率(lv)(lv)，在(zai)(zai)高压(ya)大容量系(xi)(xi)统中(zhong)(zhong)一般均采用IGBT模块，这是因为MOSFET随着电压(ya)的(de)(de)升(sheng)高其通(tong)态(tai)电阻也随之(zhi)增大，而(er)IGBT在(zai)(zai)中(zhong)(zhong)容量系(xi)(xi)统中(zhong)(zhong)占有较(jiao)(jiao)大的(de)(de)优势，而(er)在(zai)(zai)特大容量（100KVA以 上）系(xi)(xi)统中(zhong)(zhong)，一般均采用GTO作为功率(lv)(lv)元件(jian)(jian)
大件：场效应管或IGBT、变(bian)压(ya)器、电容、二极管、比较器以及(ji)3525之类的主(zhu)控。交直交逆变(bian)还有整流滤波。
功率大小和精度，关系着(zhe)电路的复(fu)杂程度。
可以看一下手机充(chong)电(dian)(dian)器(qi)，这就是一个小(xiao)开关电(dian)(dian)源(yuan)！
IGBT（绝缘栅(zha)双极(ji)晶体(ti)(ti)管(guan)）作为新型电(dian)力(li)半导(dao)体(ti)(ti)场控自关断器件，集功(gong)率MOSFET的(de)高(gao)(gao)速(su)性能与双极(ji)性器件的(de)低(di)(di)电(dian)阻于一体(ti)(ti)，具有(you)输入阻抗高(gao)(gao)，电(dian)压(ya)(ya)控制(zhi)(zhi)功(gong)耗低(di)(di)，控制(zhi)(zhi)电(dian)路简单，耐高(gao)(gao)压(ya)(ya)，承(cheng)受电(dian)流大(da)等特性，在各种电(dian)力(li)变换中获得极(ji)广泛的(de)应用。与此同时，各大(da)半导(dao)体(ti)(ti)生产厂商(shang)不断开发(fa)IGBT的(de)高(gao)(gao)耐压(ya)(ya)、大(da)电(dian)流、高(gao)(gao)速(su)、低(di)(di)饱和压(ya)(ya) 降、高(gao)(gao)可(ke)靠(kao)性、低(di)(di)成(cheng)本技术(shu)，主(zhu)要采用1um以下(xia)制(zhi)(zhi)作工艺，研制(zhi)(zhi)开发(fa)取(qu)得一些(xie)新进(jin)展(zhan)。
