光(guang)伏(fu)并网逆变器(qi)工作(zuo)原(yuan)理-结构配(pei)置组成及发电控制方式(shi)解析-KIA MOS管
信息来源：本(ben)站 日期(qi)：2018-06-01
随着绿色能(neng)(neng)源(yuan)可再(zai)生(sheng)能(neng)(neng)源(yuan)的(de)(de)(de)(de)大(da)规模(mo)开发(fa)(fa)(fa)和利(li)用，太(tai)阳(yang)能(neng)(neng)凭借其独特的(de)(de)(de)(de)优点(dian)得(de)到(dao)了更多的(de)(de)(de)(de)关(guan)(guan)注(zhu)。太(tai)阳(yang)能(neng)(neng)是(shi)当前世(shi)界上最(zui)(zui)清洁、最(zui)(zui)现实、大(da)规模(mo)开发(fa)(fa)(fa)利(li)用最(zui)(zui)有(you)(you)前景(jing)(jing)的(de)(de)(de)(de)可再(zai)生(sheng)能(neng)(neng)源(yuan)之一。其中太(tai)阳(yang)能(neng)(neng)光(guang)伏(fu)利(li)用受到(dao)世(shi)界各国的(de)(de)(de)(de)普遍关(guan)(guan)注(zhu)，而太(tai)阳(yang)能(neng)(neng)光(guang)伏(fu)并(bing)(bing)网(wang)发(fa)(fa)(fa)电(dian)(dian)(dian)是(shi)太(tai)阳(yang)能(neng)(neng)光(guang)伏(fu)利(li)用的(de)(de)(de)(de)主(zhu)要发(fa)(fa)(fa)展趋势(shi)，必将得(de)到(dao)快速的(de)(de)(de)(de)发(fa)(fa)(fa)展。本(ben)论(lun)文就(jiu)是(shi)在此背景(jing)(jing)下，对(dui)太(tai)阳(yang)能(neng)(neng)并(bing)(bing)网(wang)发(fa)(fa)(fa)电(dian)(dian)(dian)系(xi)统(tong)中最(zui)(zui)大(da)功率(lv)跟踪控(kong)制(zhi)(zhi)技(ji)术(shu)(shu)、并(bing)(bing)网(wang)控(kong)制(zhi)(zhi)策略、孤岛(dao)效应(ying)检测(ce)方法等(deng)进行(xing)了研究，具(ju)有(you)(you)重要的(de)(de)(de)(de)现实意(yi)义。太(tai)阳(yang)能(neng)(neng)光(guang)伏(fu)并(bing)(bing)网(wang)发(fa)(fa)(fa)电(dian)(dian)(dian)系(xi)统(tong)的(de)(de)(de)(de)两个核(he)心部分(fen)是(shi)太(tai)阳(yang)能(neng)(neng)电(dian)(dian)(dian)池板的(de)(de)(de)(de)最(zui)(zui)大(da)功率(lv)点(dian)跟踪（MPPT）控(kong)制(zhi)(zhi)和光(guang)伏(fu)并(bing)(bing)网(wang)逆变控(kong)制(zhi)(zhi)。本(ben)文重点(dian)对(dui)光(guang)伏(fu)发(fa)(fa)(fa)电(dian)(dian)(dian)的(de)(de)(de)(de)逆变器(qi)最(zui)(zui)大(da)功率(lv)点(dian)跟踪技(ji)术(shu)(shu)、孤岛(dao)检测(ce)技(ji)术(shu)(shu)以及(ji)光(guang)伏(fu)电(dian)(dian)(dian)站并(bing)(bing)网(wang)控(kong)制(zhi)(zhi)技(ji)术(shu)(shu)进行(xing)了讨论(lun)，并(bing)(bing)且预(yu)测(ce)了光(guang)伏(fu)发(fa)(fa)(fa)电(dian)(dian)(dian)技(ji)术(shu)(shu)的(de)(de)(de)(de)发(fa)(fa)(fa)展趋势(shi)。
光伏并(bing)网逆变器系(xi)统(tong)是将太(tai)阳(yang)能(neng)光(guang)伏阵(zhen)(zhen)列(lie)发(fa)出的(de)直流电(dian)(dian)(dian)(dian)转化为与公共(gong)电(dian)(dian)(dian)(dian)网(wang)电(dian)(dian)(dian)(dian)压同(tong)(tong)频同(tong)(tong)相的(de)交流电(dian)(dian)(dian)(dian)，因此该系(xi)统(tong)是既能(neng)满足本(ben)地(di)负(fu)(fu)(fu)载(zai)用电(dian)(dian)(dian)(dian)又能(neng)向公共(gong)电(dian)(dian)(dian)(dian)网(wang)送(song)(song)电(dian)(dian)(dian)(dian)。一般(ban)情(qing)况下，公共(gong)电(dian)(dian)(dian)(dian)网(wang)系(xi)统(tong)可看(kan)作是容量(liang)为无穷大的(de)交流电(dian)(dian)(dian)(dian)压源。当(dang)太(tai)阳(yang)能(neng)光(guang)伏发(fa)电(dian)(dian)(dian)(dian)并网(wang)系(xi)统(tong)中太(tai)阳(yang)能(neng)光(guang)伏阵(zhen)(zhen)列(lie)的(de)发(fa)电(dian)(dian)(dian)(dian)量(liang)小于本(ben)地(di)负(fu)(fu)(fu)载(zai)用电(dian)(dian)(dian)(dian)量(liang)时，本(ben)地(di)负(fu)(fu)(fu)载(zai)电(dian)(dian)(dian)(dian)力(li)不足部(bu)分(fen)由公共(gong)电(dian)(dian)(dian)(dian)网(wang)输送(song)(song)供给；当(dang)光(guang)伏电(dian)(dian)(dian)(dian)池阵(zhen)(zhen)列(lie)的(de)发(fa)电(dian)(dian)(dian)(dian)量(liang)大于本(ben)地(di)负(fu)(fu)(fu)载(zai)用电(dian)(dian)(dian)(dian)量(liang)时，太(tai)阳(yang)能(neng)光(guang)伏系(xi)统(tong)将多(duo)余的(de)电(dian)(dian)(dian)(dian)能(neng)输送(song)(song)给公共(gong)电(dian)(dian)(dian)(dian)网(wang)，实现并网(wang)发(fa)电(dian)(dian)(dian)(dian)
太(tai)阳(yang)能(neng)光伏发(fa)电(dian)并(bing)网系统(tong)组成(cheng)(cheng)如图(tu)所示，该系统(tong)一(yi)般(ban)由太(tai)阳(yang)能(neng)电(dian)池光伏阵列(lie)(lie)、MPPT控制(zhi)、DC/DC变(bian)换器、驱动(dong)电(dian)路以及控制(zhi)器组成(cheng)(cheng)，其中变(bian)换器可(ke)将太(tai)阳(yang)能(neng)光伏阵列(lie)(lie)发(fa)出(chu)的(de)(de)直流电(dian)逆变(bian)成(cheng)(cheng)正(zheng)弦交(jiao)流电(dian)并(bing)入公共(gong)电(dian)网。控制(zhi)器主要控制(zhi)逆变(bian)器并(bing)网电(dian)流的(de)(de)波(bo)形、功(gong)(gong)率(lv)以及光伏电(dian)池最大功(gong)(gong)率(lv)点的(de)(de)跟踪，以便向电(dian)网传送的(de)(de)功(gong)(gong)率(lv)与太(tai)阳(yang)能(neng)光伏电(dian)池阵列(lie)(lie)所发(fa)的(de)(de)最大功(gong)(gong)率(lv)电(dian)能(neng)相匹配。
如果光(guang)(guang)伏(fu)并(bing)(bing)(bing)网逆(ni)(ni)变(bian)(bian)(bian)器的(de)输(shu)出采用(yong)电(dian)(dian)压控(kong)制(zhi)，则(ze)相(xiang)当于是电(dian)(dian)压源(yuan)与(yu)电(dian)(dian)压源(yuan)并(bing)(bing)(bing)联运行；如果光(guang)(guang)伏(fu)并(bing)(bing)(bing)网逆(ni)(ni)变(bian)(bian)(bian)器的(de)输(shu)出采用(yong)电(dian)(dian)流(liu)控(kong)制(zhi)，就相(xiang)当于电(dian)(dian)流(liu)源(yuan)与(yu)电(dian)(dian)压源(yuan)并(bing)(bing)(bing)联运行。逆(ni)(ni)变(bian)(bian)(bian)器采用(yong)电(dian)(dian)流(liu)控(kong)制(zhi)时，只需控(kong)制(zhi)逆(ni)(ni)变(bian)(bian)(bian)器的(de)输(shu)出电(dian)(dian)流(liu)跟(gen)踪电(dian)(dian)网电(dian)(dian)压，控(kong)制(zhi)输(shu)出电(dian)(dian)流(liu)与(yu)电(dian)(dian)网电(dian)(dian)压同(tong)频同(tong)相(xiang)，这样系统的(de)功率(lv)因(yin)数为1。目(mu)前，光(guang)(guang)伏(fu)并(bing)(bing)(bing)网逆(ni)(ni)变(bian)(bian)(bian)器一般都(dou)采用(yong)电(dian)(dian)压源(yuan)输(shu)入、电(dian)(dian)流(liu)源(yuan)输(shu)出的(de)控(kong)制(zhi)方式(shi)。
太阳能光伏(fu)(fu)发电(dian)(dian)(dian)(dian)并(bing)网(wang)系统(tong)的(de)逆变器(qi)通常采用电(dian)(dian)(dian)(dian)流控制(zhi)模(mo)式，这样整个系统(tong)系统(tong)实(shi)际(ji)上就是(shi)一个电(dian)(dian)(dian)(dian)压源和电(dian)(dian)(dian)(dian)流源并(bing)联的(de)系统(tong)。逆变器(qi)并(bing)网(wang)运行的(de)主要(yao)控制(zhi)目标(biao)是(shi)要(yao)保证(zheng)逆变器(qi)输(shu)(shu)出(chu)电(dian)(dian)(dian)(dian)流与公共电(dian)(dian)(dian)(dian)网(wang)电(dian)(dian)(dian)(dian)压同频同相，并(bing)且(qie)还(hai)能实(shi)时跟踪(zong)电(dian)(dian)(dian)(dian)网(wang)电(dian)(dian)(dian)(dian)压实(shi)现最大功率跟踪(zong)控制(zhi)。通过采用锁相控制(zhi)技术实(shi)现太阳能光伏(fu)(fu)发电(dian)(dian)(dian)(dian)并(bing)网(wang)系统(tong)输(shu)(shu)出(chu)的(de)并(bing)网(wang)电(dian)(dian)(dian)(dian)流与公共电(dian)(dian)(dian)(dian)网(wang)电(dian)(dian)(dian)(dian)压相位(wei)同步(bu)，保证(zheng)系统(tong)输(shu)(shu)出(chu)的(de)功率因数为1。光伏并网(wang)逆变器运(yun)行时还要(yao)控制并(bing)网电流的总畸(ji)变失真(zhen)要(yao)低，以减小对电网的谐波(bo)影响，使并(bing)网系统的有功功率输出达到最大。
光(guang)伏并网(wang)(wang)(wang)发电系统(tong)(tong)可(ke)以按照系统(tong)(tong)功能分为两(liang)类：一种为不含蓄电池(chi)环(huan)节的不可(ke)调(diao)度式光(guang)伏并网(wang)(wang)(wang)发电系统(tong)(tong)；另一种为含有蓄电池(chi)组的可(ke)调(diao)度式光(guang)伏并网(wang)(wang)(wang)发电系统(tong)(tong)。系统(tong)(tong)结构图如1．1所示(shi)
可调(diao)度(du)式光伏并网(wang)发电系(xi)(xi)(xi)(xi)(xi)统(tong)增加了(le)(le)储能(neng)环(huan)节(jie)，系(xi)(xi)(xi)(xi)(xi)统(tong)首先对蓄电池进行(xing)充电，然(ran)后根据需要将系(xi)(xi)(xi)(xi)(xi)统(tong)用作并网(wang)或者经逆(ni)变后独立(li)使用，系(xi)(xi)(xi)(xi)(xi)统(tong)工作时(shi)间和并网(wang)功(gong)率大(da)小(xiao)可以(yi)人为(wei)设定。可调(diao)度(du)式并网(wang)系(xi)(xi)(xi)(xi)(xi)统(tong)虽然(ran)在(zai)表面上看(kan)来(lai)比不可调(diao)度(du)式系(xi)(xi)(xi)(xi)(xi)统(tong)功(gong)能(neng)齐全，但(dan)由于(yu)增加了(le)(le)储能(neng)环(huan)节(jie)，带(dai)来(lai)了(le)(le)很(hen)多严重的(de)问题，这(zhei)是因为(wei)：
(1)由于采用(yong)蓄(xu)电(dian)池作为储能设备(bei)，系(xi)统必须(xu)增加(jia)蓄(xu)电(dian)池的(de)充(chong)电(dian)装置，这就增加(jia)了成本并且降低了系(xi)统的(de)可(ke)靠性。
(2)蓄电(dian)池(chi)组的(de)(de)寿(shou)(shou)命较短。目前免维修蓄电(dian)池(chi)在良好环境下的(de)(de)工(gong)作(zuo)寿(shou)(shou)命通常为(wei)5年，而光伏(fu)阵列稳定工(gong)作(zuo)的(de)(de)寿(shou)(shou)命则在25~30年之问，这样就(jiu)需要定期更换(huan)蓄电(dian)池(chi)组，又(you)增加了许多系统的(de)(de)投入。
(3)蓄(xu)电(dian)池组(zu)较(jiao)(jiao)为(wei)笨重，需要占用较(jiao)(jiao)大(da)空间，同时要防止泄露出(chu)腐(fu)蚀性液体，另外(wai)报废的蓄(xu)电(dian)池组(zu)要专门处理，否(fou)则会(hui)造成污(wu)染(ran)。
基于上述原因(yin)，目前的光伏并网(wang)系统(tong)主(zhu)要以不可调(diao)度(du)式系统(tong)为主(zhu)。不可调(diao)度(du)式光伏并网(wang)发电(dian)系统(tong)的集成度(du)高，其安装和调(diao)试(shi)相(xiang)对方便，可靠(kao)性(xing)也高。
根据其(qi)所产生的电(dian)能能否返送到电(dian)力系统，可以分为逆(ni)流(liu)(liu)型，无逆(ni)流(liu)(liu)型，切(qie)换型，直、交流(liu)(liu)型，混合型和地域(yu)型等。
（1）直、交流型(xing)并网发电系(xi)统(tong)(tong)，该系(xi)统(tong)(tong)就(jiu)是将光伏并网逆变器发(fa)电系统(tong)(tong)所产生的(de)直流(liu)电直接供用(yong)(yong)电设(she)备(bei)使用(yong)(yong)。该系统(tong)(tong)有时与电力(li)系统(tong)(tong)并用(yong)(yong)，主要(yao)目的(de)是为了提高(gao)供电的(de)可靠(kao)性(xing)。
（2）混(hun)合(he)(he)并网发(fa)(fa)(fa)(fa)(fa)电(dian)(dian)(dian)(dian)系(xi)(xi)统(tong)(tong)当(dang)太(tai)(tai)阳(yang)能(neng)(neng)光(guang)伏(fu)发(fa)(fa)(fa)(fa)(fa)电(dian)(dian)(dian)(dian)所(suo)提(ti)供的电(dian)(dian)(dian)(dian)力不(bu)足(zu)(如(ru)遇到连续阴(yin)雨(yu)天气、冬季日照(zhao)时(shi)间过短等)，需要使(shi)用(yong)(yong)其他能(neng)(neng)源来补充时(shi)，可以(yi)将风(feng)力发(fa)(fa)(fa)(fa)(fa)电(dian)(dian)(dian)(dian)、燃(ran)料(liao)电(dian)(dian)(dian)(dian)池发(fa)(fa)(fa)(fa)(fa)电(dian)(dian)(dian)(dian)等其他发(fa)(fa)(fa)(fa)(fa)电(dian)(dian)(dian)(dian)系(xi)(xi)统(tong)(tong)与(yu)(yu)光(guang)伏(fu)发(fa)(fa)(fa)(fa)(fa)电(dian)(dian)(dian)(dian)系(xi)(xi)统(tong)(tong)并用(yong)(yong)，这(zhei)样的系(xi)(xi)统(tong)(tong)叫做混(hun)合(he)(he)并网发(fa)(fa)(fa)(fa)(fa)电(dian)(dian)(dian)(dian)系(xi)(xi)统(tong)(tong)，如(ru)太(tai)(tai)阳(yang)能(neng)(neng)光(guang)伏(fu)、燃(ran)料(liao)电(dian)(dian)(dian)(dian)池并网发(fa)(fa)(fa)(fa)(fa)电(dian)(dian)(dian)(dian)系(xi)(xi)统(tong)(tong)和风(feng)、光(guang)互(hu)补型(xing)并网发(fa)(fa)(fa)(fa)(fa)电(dian)(dian)(dian)(dian)系(xi)(xi)统(tong)(tong)：①太(tai)(tai)阳(yang)能(neng)(neng)光(guang)伏(fu)、燃(ran)料(liao)电(dian)(dian)(dian)(dian)池并网发(fa)(fa)(fa)(fa)(fa)电(dian)(dian)(dian)(dian)系(xi)(xi)统(tong)(tong)，为综(zong)合(he)(he)利(li)用(yong)(yong)能(neng)(neng)源，提(ti)高能(neng)(neng)源的综(zong)合(he)(he)利(li)用(yong)(yong)率，节约(yue)电(dian)(dian)(dian)(dian)费(fei)，减少环境(jing)污染(ran)，有时(shi)将燃(ran)料(liao)电(dian)(dian)(dian)(dian)池与(yu)(yu)太(tai)(tai)阳(yang)能(neng)(neng)光(guang)伏(fu)发(fa)(fa)(fa)(fa)(fa)电(dian)(dian)(dian)(dian)系(xi)(xi)统(tong)(tong)并网在一(yi)起(qi)，构成太(tai)(tai)阳(yang)能(neng)(neng)光(guang)伏(fu)、燃(ran)料(liao)电(dian)(dian)(dian)(dian)池并网系(xi)(xi)统(tong)(tong)；②风(feng)、光(guang)互(hu)补型(xing)并网发(fa)(fa)(fa)(fa)(fa)电(dian)(dian)(dian)(dian)系(xi)(xi)统(tong)(tong)，当(dang)利(li)用(yong)(yong)光(guang)伏(fu)发(fa)(fa)(fa)(fa)(fa)电(dian)(dian)(dian)(dian)提(ti)供的电(dian)(dian)(dian)(dian)力不(bu)足(zu)时(shi)，可以(yi)利(li)用(yong)(yong)风(feng)力发(fa)(fa)(fa)(fa)(fa)电(dian)(dian)(dian)(dian)；当(dang)风(feng)力发(fa)(fa)(fa)(fa)(fa)电(dian)(dian)(dian)(dian)不(bu)足(zu)时(shi)，可以(yi)利(li)用(yong)(yong)光(guang)伏(fu)发(fa)(fa)(fa)(fa)(fa)电(dian)(dian)(dian)(dian)，这(zhei)样的系(xi)(xi)统(tong)(tong)称(cheng)为风(feng)、光(guang)互(hu)补式并网发(fa)(fa)(fa)(fa)(fa)电(dian)(dian)(dian)(dian)系(xi)(xi)统(tong)(tong)。
风(feng)(feng)光(guang)互补(bu)(bu)系(xi)(xi)(xi)统(tong)(tong)(tong)同时利用(yong)太阳(yang)能和(he)风(feng)(feng)能发(fa)(fa)电(dian)(dian)(dian)，因此对气象资(zi)源的(de)利用(yong)更(geng)加充分。可(ke)实现昼夜(ye)发(fa)(fa)电(dian)(dian)(dian)。在适宜气象条件下，风(feng)(feng)光(guang)互补(bu)(bu)系(xi)(xi)(xi)统(tong)(tong)(tong)可(ke)提高系(xi)(xi)(xi)统(tong)(tong)(tong)供电(dian)(dian)(dian)的(de)连续性(xing)和(he)稳定性(xing)。由(you)于(yu)通常夜(ye)晚无阳(yang)光(guang)时恰好(hao)风(feng)(feng)力较大(da)，所以(yi)(yi)互补(bu)(bu)性(xing)好(hao)，可(ke)以(yi)(yi)减少(shao)系(xi)(xi)(xi)统(tong)(tong)(tong)的(de)太阳(yang)能板配(pei)置(zhi)，从而(er)大(da)大(da)降低系(xi)(xi)(xi)统(tong)(tong)(tong)造价，单(dan)位容(rong)量的(de)系(xi)(xi)(xi)统(tong)(tong)(tong)初投资(zi)和(he)发(fa)(fa)电(dian)(dian)(dian)成(cheng)本均低于(yu)独立的(de)光(guang)伏系(xi)(xi)(xi)统(tong)(tong)(tong)。该(gai)系(xi)(xi)(xi)统(tong)(tong)(tong)发(fa)(fa)电(dian)(dian)(dian)有余时可(ke)向电(dian)(dian)(dian)网系(xi)(xi)(xi)统(tong)(tong)(tong)供电(dian)(dian)(dian)(卖电(dian)(dian)(dian))；当该(gai)系(xi)(xi)(xi)统(tong)(tong)(tong)所发(fa)(fa)出(chu)的(de)电(dian)(dian)(dian)能不足时，可(ke)以(yi)(yi)由(you)电(dian)(dian)(dian)网系(xi)(xi)(xi)统(tong)(tong)(tong)供电(dian)(dian)(dian)(买电(dian)(dian)(dian))。
（3）逆(ni)流(liu)型太阳能(neng)(neng)(neng)并(bing)网发(fa)(fa)电(dian)系(xi)统(tong)，当(dang)太阳能(neng)(neng)(neng)光(guang)伏(fu)系(xi)统(tong)发(fa)(fa)出的(de)电(dian)能(neng)(neng)(neng)充裕时(shi)，可(ke)将剩余电(dian)能(neng)(neng)(neng)向电(dian)网系(xi)统(tong)供(gong)电(dian)；当(dang)太阳能(neng)(neng)(neng)光(guang)伏(fu)系(xi)统(tong)提(ti)供(gong)的(de)电(dian)力不足时(shi)，可(ke)利用外接电(dian)力系(xi)统(tong)供(gong)电(dian)。这种系(xi)统(tong)称为逆(ni)流(liu)式并(bing)网发(fa)(fa)电(dian)系(xi)统(tong)。
（4）无(wu)逆(ni)流型(xing)并(bing)网发电系统(tong)光伏并网逆(ni)变器(qi)发(fa)电(dian)系(xi)(xi)统(tong)，即使发(fa)电(dian)充裕(yu)也不向电(dian)力系(xi)(xi)统(tong)供电(dian)，但(dan)当太阳能光(guang)伏发(fa)电(dian)系(xi)(xi)统(tong)供电(dian)不足时，可(ke)以利(li)用外接电(dian)力系(xi)(xi)统(tong)供电(dian)。这种(zhong)系(xi)(xi)统(tong)称(cheng)为无逆流式并网发(fa)电(dian)系(xi)(xi)统(tong)。
（5）切(qie)换型并(bing)网发电系(xi)统(tong)，该系(xi)统(tong)可(ke)(ke)分为(wei)以下两种：①切(qie)换型并(bing)网发电系(xi)统(tong)当多(duo)云、阴(yin)雨、日光(guang)(guang)不(bu)足(zu)、晚间(jian)或蓄电池(chi)(chi)容(rong)量不(bu)足(zu)时(shi)，切(qie)换器能(neng)自(zi)动(dong)地换向电力系(xi)统(tong)一(yi)侧，由(you)电网直接向负载供(gong)电。设(she)计(ji)时(shi)，若采(cai)用(yong)大容(rong)量的(de)(de)蓄电池(chi)(chi)，投资(zi)费用(yong)增大；采(cai)用(yong)切(qie)换器可(ke)(ke)使用(yong)小容(rong)量的(de)(de)蓄电池(chi)(chi)，则成本可(ke)(ke)以明显(xian)降低。②自(zi)运(yun)行(xing)切(qie)换型并(bing)网系(xi)统(tong)当电力系(xi)统(tong)因多(duo)种原因突然停电时(shi)，光(guang)(guang)伏系(xi)统(tong)可(ke)(ke)以通过(guo)保护装置自(zi)动(dong)使电力系(xi)统(tong)与光(guang)(guang)伏系(xi)统(tong)分离。
为(wei)了最(zui)大(da)(da)限(xian)度的利用好(hao)太阳(yang)能资源，现阶段太阳(yang)能光伏并网技(ji)术(shu)(shu)的研究方向为(wei)最(zui)大(da)(da)功(gong)率点跟(gen)踪技(ji)术(shu)(shu)，并网逆变器控制技(ji)术(shu)(shu)，孤岛(dao)检测(ce)技(ji)术(shu)(shu)。
最大(da)功(gong)(gong)率点(dian)跟踪(zong)技术是通过调整光(guang)伏(fu)阵列端电(dian)压(ya)，使(shi)光(guang)伏(fu)阵列在不同的光(guang)照和温度下(xia)实(shi)现最大(da)功(gong)(gong)率输(shu)出(chu)，目前常用的MPPT方法(fa)主要有(you)恒电(dian)压(ya)跟踪(zong)方法(fa)，干扰观测法(fa)和电(dian)导增(zeng)量法(fa)
虽然光伏(fu)(fu)阵列(lie)的(de)最大(da)(da)功(gong)(gong)率(lv)点(dian)功(gong)(gong)率(lv)随着光照强度的(de)增强而增大(da)(da).但(dan)最大(da)(da)功(gong)(gong)率(lv)点(dian)电(dian)(dian)压(ya)(ya)(ya)基本(ben)变化(hua)不(bu)大(da)(da)。因此，只(zhi)要(yao)通过光伏(fu)(fu)阵列(lie)生产商提供(gong)的(de)光伏(fu)(fu)阵列(lie)的(de)特性数据或者通过实际测量就(jiu)(jiu)可以得(de)到近(jin)似最大(da)(da)功(gong)(gong)率(lv)点(dian)电(dian)(dian)压(ya)(ya)(ya)U..系(xi)统(tong)只(zhi)需将(jiang)光伏(fu)(fu)阵列(lie)的(de)输出电(dian)(dian)压(ya)(ya)(ya)固定在U.上(shang).就(jiu)(jiu)可以使光伏(fu)(fu)阵列(lie)以近(jin)似最大(da)(da)功(gong)(gong)率(lv)输出。这样就(jiu)(jiu)将(jiang)最大(da)(da)功(gong)(gong)率(lv)点(dian)跟踪控制简化(hua)成(cheng)稳(wen)(wen)压(ya)(ya)(ya)控制，光伏(fu)(fu)阵列(lie)的(de)工作点(dian)比较稳(wen)(wen)定，实现方法简单(dan)，系(xi)统(tong)稳(wen)(wen)定可靠。
但是.这种方(fang)法忽略了(le)温(wen)(wen)(wen)度对光伏阵(zhen)列(lie)工作(zuo)(zuo)特性的形(xing)响(xiang)。当温(wen)(wen)(wen)度上升(sheng)时，光伏阵(zhen)列(lie)的最大(da)功(gong)率(lv)点电压下降，并且变(bian)化较(jiao)(jiao)大(da)。如(ru)果仍(reng)然(ran)采用(yong)固定电压法控制.光伏阵(zhen)列(lie)的输出功(gong)率(lv)将损失较(jiao)(jiao)大(da).无法充分发挥作(zuo)(zuo)用(yong)，效率(lv)下降.因(yin)此(ci)，在冬夏、早晚等温(wen)(wen)(wen)度变(bian)化较(jiao)(jiao)大(da)时.采用(yong)固定电压控制并不合适，此(ci)时，可以(yi)通过(guo)以(yi)下方(fang)法根据实际情况改(gai)变(bian)Um：
1)根据冬(dong)夏(xia)、早晚的实(shi)际情(qing)况，手工(gong)调整Um.由(you)于(yu)需要人工(gong)维护，费时费力(li)，因此较少(shao)采(cai)用。
2)将(jiang)光伏阵列(lie)在不同温(wen)度下(xia)对应(ying)的(de)(de)Um.存储(chu)在系(xi)统(tong)的(de)(de)存储(chu)器内。根据温(wen)度传(chuan)感器测(ce)量得到(dao)的(de)(de)温(wen)度相应(ying)的(de)(de)将(jiang)光伏阵列(lie)输出电压(ya)固定(ding)在此温(wen)度下(xia)对应(ying)的(de)(de)Um。
3)根据光伏(fu)阵列(lie)的最大功率点电(dian)压与开路电(dian)压之间存在近(jin)似的比(bi)例(li)关系这一特性改变Um。
根据以上分析，可知因(yin)定电(dian)压法的特点如(ru)下:
1)原理简单，控制方法容易实现.只(zhi)需耍(shua)将光伏阵列(lie)输出(chu)电(dian)压固定在近似最大(da)功(gong)率点电(dian)压Um处即可(ke)。
2)由于光伏阵(zhen)列(lie)输出电(dian)压固(gu)定在某(mou)一特定值，因此系统比较(jiao)稳定.不易出现振荡.
3)在外部(bu)环境发生(sheng)变化(hua)的(de)情况下控(kong)制精度较(jiao)低.因此适用子(zi)外部(bu)环境(光照(zhao)强(qiang)度、温(wen)度等)变化(hua)不(bu)大的(de)场合(he)，如太空。
光伏并网系统(tong)是将太阳能电池(chi)板(ban)产(chan)生的直流电转化为(wei)正弦(xian)交流电，从而向电网供(gong)电的装(zhuang)置，它实际上是一(yi)个有源(yuan)逆(ni)变系统(tong)。光伏并网逆(ni)变器(qi)控(kong)制(zhi)目标(biao)是(shi)：控(kong)制(zhi)逆变(bian)电(dian)(dian)(dian)(dian)路(lu)输(shu)出的(de)(de)(de)交流电(dian)(dian)(dian)(dian)流为(wei)(wei)稳(wen)(wen)定(ding)的(de)(de)(de)高质量(liang)的(de)(de)(de)正弦(xian)波，且与电(dian)(dian)(dian)(dian)网电(dian)(dian)(dian)(dian)压同频、同相。光(guang)伏并网系(xi)统逆变(bian)器按控(kong)制(zhi)方式(shi)(shi)分(fen)类，可以分(fen)为(wei)(wei)电(dian)(dian)(dian)(dian)压源(yuan)(yuan)(yuan)(yuan)电(dian)(dian)(dian)(dian)压控(kong)制(zhi)、电(dian)(dian)(dian)(dian)压源(yuan)(yuan)(yuan)(yuan)电(dian)(dian)(dian)(dian)流控(kong)制(zhi)、电(dian)(dian)(dian)(dian)流源(yuan)(yuan)(yuan)(yuan)电(dian)(dian)(dian)(dian)压控(kong)制(zhi)和电(dian)(dian)(dian)(dian)流源(yuan)(yuan)(yuan)(yuan)电(dian)(dian)(dian)(dian)流控(kong)制(zhi)四种(zhong)方式(shi)(shi)。电(dian)(dian)(dian)(dian)压源(yuan)(yuan)(yuan)(yuan)型逆变(bian)器是(shi)采用电(dian)(dian)(dian)(dian)容(rong)(rong)作(zuo)为(wei)(wei)储能元(yuan)件，在直流输(shu)入侧(ce)并联大电(dian)(dian)(dian)(dian)容(rong)(rong)用作(zuo)无(wu)功功率(lv)缓冲环节，构(gou)(gou)成逆变(bian)器低阻抗(kang)的(de)(de)(de)电(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)内(nei)阻特(te)性，即电(dian)(dian)(dian)(dian)压源(yuan)(yuan)(yuan)(yuan)特(te)性。以电(dian)(dian)(dian)(dian)流源(yuan)(yuan)(yuan)(yuan)为(wei)(wei)输(shu)入方式(shi)(shi)的(de)(de)(de)逆变(bian)器，其(qi)直流侧(ce)需串(chuan)联一个大电(dian)(dian)(dian)(dian)感(gan)作(zuo)为(wei)(wei)无(wu)功元(yuan)件储存无(wu)功功率(lv)，构(gou)(gou)成逆变(bian)器高阻抗(kang)的(de)(de)(de)电(dian)(dian)(dian)(dian)流源(yuan)(yuan)(yuan)(yuan)特(te)性，提供稳(wen)(wen)定(ding)的(de)(de)(de)直流电(dian)(dian)(dian)(dian)流输(shu)入，但是(shi)串(chuan)入大电(dian)(dian)(dian)(dian)感(gan)往往会导(dao)致系(xi)统动态响应差，因(yin)此，目前世(shi)界范围内(nei)大部分(fen)光伏并(bing)网逆变器均(jun)采用以(yi)电压源输入为主的方式。
并网逆变(bian)器中逆变(bian)部(bu)分控制(zhi)(zhi)(zhi)的关键量是(shi)矢(shi)量图中的电(dian)流(liu)，可以通过对(dui)输出电(dian)压(ya)的控制(zhi)(zhi)(zhi)完成对(dui)I的控制(zhi)(zhi)(zhi)或者直接(jie)对(dui)I进(jin)行控制(zhi)(zhi)(zhi)，完成对(dui)交流(liu)侧电(dian)流(liu)、功率因(yin)数(shu)的控制(zhi)(zhi)(zhi)。因(yin)此，根据电(dian)流(liu)控制(zhi)(zhi)(zhi)方法的不同，可以将电(dian)流(liu)控制(zhi)(zhi)(zhi)方式分为以下两种控制(zhi)(zhi)(zhi)模(mo)式：
1)间接电流控制
它(ta)是(shi)根据稳态(tai)电(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)向(xiang)(xiang)量(liang)的(de)给定、PWM基波(bo)电(dian)(dian)(dian)(dian)(dian)(dian)(dian)压(ya)向(xiang)(xiang)量(liang)的(de)幅(fu)值和相(xiang)位，分别进行闭环(huan)控制，进而通(tong)过(guo)(guo)电(dian)(dian)(dian)(dian)(dian)(dian)(dian)压(ya)控制实(shi)现对并网(wang)(wang)(wang)电(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)的(de)控制。该(gai)控制策略虽然简(jian)单且不(bu)需(xu)检测并网(wang)(wang)(wang)电(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)，但动(dong)态(tai)响应慢(man)，存在瞬时直流(liu)电(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)偏移，尤其(qi)是(shi)瞬态(tai)过(guo)(guo)冲电(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)几(ji)乎是(shi)稳态(tai)值的(de)两倍(bei)；从稳态(tai)向(xiang)(xiang)量(liang)关(guan)系(xi)进行电(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)控制，其(qi)前提条件(jian)是(shi)电(dian)(dian)(dian)(dian)(dian)(dian)(dian)网(wang)(wang)(wang)电(dian)(dian)(dian)(dian)(dian)(dian)(dian)压(ya)不(bu)发生(sheng)畸变(bian)，而实(shi)际上由于(yu)电(dian)(dian)(dian)(dian)(dian)(dian)(dian)网(wang)(wang)(wang)内阻抗、负(fu)载的(de)变(bian)化以及各种非线性负(fu)载扰动(dong)等(deng)情况的(de)存在，尤其(qi)是(shi)在瞬态(tai)过(guo)(guo)程中电(dian)(dian)(dian)(dian)(dian)(dian)(dian)网(wang)(wang)(wang)电(dian)(dian)(dian)(dian)(dian)(dian)(dian)压(ya)的(de)波(bo)形会发生(sheng)畸变(bian)。电(dian)(dian)(dian)(dian)(dian)(dian)(dian)网(wang)(wang)(wang)电(dian)(dian)(dian)(dian)(dian)(dian)(dian)压(ya)波(bo)形的(de)畸变(bian)会直接(jie)影(ying)响着系(xi)统控制的(de)效果，因此间接(jie)电(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)控制方法控制电(dian)(dian)(dian)(dian)(dian)(dian)(dian)路复杂、信号运算过(guo)(guo)程中要(yao)用(yong)到电(dian)(dian)(dian)(dian)(dian)(dian)(dian)路参数、对系(xi)统参数有一(yi)定的(de)依赖(lai)性、系(xi)统的(de)动(dong)态(tai)响应速度也比较慢(man)。
2)直接电流控制
通过运算(suan)求出交流(liu)(liu)电(dian)(dian)流(liu)(liu)，再(zai)引入交流(liu)(liu)电(dian)(dian)流(liu)(liu)反馈，通过对交流(liu)(liu)电(dian)(dian)流(liu)(liu)的直接控制，使(shi)其跟踪指令电(dian)(dian)流(liu)(liu)值。对于光伏并网逆变器来说为(wei)了获(huo)得与电(dian)(dian)网电(dian)(dian)压(ya)同步(bu)的(de)给定正(zheng)弦(xian)电(dian)(dian)流波形(xing)(xing)，通常用电(dian)(dian)网电(dian)(dian)压(ya)信号乘以电(dian)(dian)流有(you)(you)功给定，产生正(zheng)弦(xian)参(can)考电(dian)(dian)流波形(xing)(xing)，然(ran)后(hou)使(shi)其输出(chu)电(dian)(dian)流跟踪(zong)这一指令电(dian)(dian)流。具有(you)(you)控制电(dian)(dian)路相对简单、对系(xi)统参(can)数的(de)依(yi)赖性(xing)低、系(xi)统动态响应(ying)速度快(kuai)等优点。
光伏并(bing)网逆(ni)变器的(de)选(xuan)用，首先要考(kao)虑具有足够的(de)额(e)定容量，以(yi)满足最大负(fu)荷下设(she)备对电功率的(de)要求(qiu)。对于以(yi)单一设(she)备为(wei)负(fu)载的(de)逆变器(qi)，其额(e)定容量的(de)选(xuan)取(qu)较为(wei)简单。
当用电(dian)设备(bei)为纯阻性负载(zai)或功(gong)率因数大(da)于0.9时，选取逆变(bian)器(qi)(qi)的(de)额(e)定容(rong)(rong)量(liang)为用电(dian)设备(bei)容(rong)(rong)量(liang)的(de)1.1～1.15倍即可。同时逆变(bian)器(qi)(qi)还应具(ju)有抗容(rong)(rong)性和感性负载(zai)冲击的(de)能(neng)力。
对一般电感(gan)性负载，如电机、冰(bing)箱、空调、洗衣机、大功(gong)率水泵等，在起(qi)(qi)动时(shi)，其瞬时(shi)功(gong)率可(ke)能是其额(e)定(ding)功(gong)率的5～6倍(bei)，此时(shi)，逆(ni)(ni)变(bian)器(qi)将承受很大的瞬时(shi)浪涌。针对此类系统，逆(ni)(ni)变(bian)器(qi)的额(e)定(ding)容量应留有充分的余量，以保证负载能可(ke)靠起(qi)(qi)动，高性能的逆(ni)(ni)变(bian)器(qi)可(ke)做(zuo)到连续多次(ci)满负荷起(qi)(qi)动而不损坏功(gong)率器(qi)件。小(xiao)型(xing)逆(ni)(ni)变(bian)器(qi)为了自身(shen)安全，有时(shi)需采用软起(qi)(qi)动或限流(liu)起(qi)(qi)动的方式。
光伏并网逆变器光伏发电(dian)(dian)系(xi)(xi)统(tong)(tong)是(shi)(shi)由太阳能电(dian)(dian)池方阵，蓄(xu)电(dian)(dian)池组(zu)，充(chong)放(fang)电(dian)(dian)控(kong)制器(qi)，逆(ni)变(bian)器(qi)，交流配电(dian)(dian)柜(ju)，太阳跟踪控(kong)制系(xi)(xi)统(tong)(tong)等设备组(zu)成。其部分(fen)设备的作(zuo)用是(shi)(shi)：
4.1电池方阵
在有光(guang)照(zhao)（无论是(shi)(shi)太(tai)阳(yang)光(guang)，还是(shi)(shi)其(qi)它发(fa)光(guang)体产(chan)生(sheng)(sheng)的光(guang)照(zhao)）情况下(xia)，电(dian)(dian)池(chi)吸(xi)收光(guang)能(neng)，电(dian)(dian)池(chi)两端出现异号电(dian)(dian)荷(he)的积(ji)累，即产(chan)生(sheng)(sheng)“光(guang)生(sheng)(sheng)电(dian)(dian)压”，这就(jiu)是(shi)(shi)“光(guang)生(sheng)(sheng)伏特(te)效(xiao)应”。在光(guang)生(sheng)(sheng)伏特(te)效(xiao)应的作用下(xia)，太(tai)阳(yang)能(neng)电(dian)(dian)池(chi)的两端产(chan)生(sheng)(sheng)电(dian)(dian)动势，将光(guang)能(neng)转换(huan)成(cheng)电(dian)(dian)能(neng)，是(shi)(shi)能(neng)量转换(huan)的器件。太(tai)阳(yang)能(neng)电(dian)(dian)池(chi)一般(ban)为硅(gui)电(dian)(dian)池(chi)，分为单晶(jing)硅(gui)太(tai)阳(yang)能(neng)电(dian)(dian)池(chi)，多(duo)晶(jing)硅(gui)太(tai)阳(yang)能(neng)电(dian)(dian)池(chi)和非单晶(jing)硅(gui)太(tai)阳(yang)能(neng)电(dian)(dian)池(chi)三种(zhong)。
4.2蓄电池组
其作用(yong)是贮存太(tai)阳(yang)能电池方阵受光照时发出(chu)的(de)电能并可随时向负载供电。太(tai)阳(yang)能电池发电对所用(yong)蓄电池组的(de)基本要(yao)求是：a.自放电率低(di)；b.使用(yong)寿(shou)命长；c.深放电能力强；d.充(chong)电效率高；e.少维(wei)护(hu)或免维(wei)护(hu)；f.工作温度范围(wei)宽；g.价(jia)格低(di)廉(lian)。
4.3控制器
是能(neng)自动防止蓄(xu)电(dian)池(chi)过(guo)充(chong)(chong)电(dian)和过(guo)放电(dian)的设(she)备(bei)。由(you)于(yu)蓄(xu)电(dian)池(chi)的循环充(chong)(chong)放电(dian)次数及放电(dian)深度(du)是决定蓄(xu)电(dian)池(chi)使用(yong)寿命的重要(yao)因(yin)素，因(yin)此能(neng)控制(zhi)蓄(xu)电(dian)池(chi)组过(guo)充(chong)(chong)电(dian)或过(guo)放电(dian)的充(chong)(chong)放电(dian)控制(zhi)器(qi)是必(bi)不可少(shao)的设(she)备(bei)。
4.4逆变器
是将直流(liu)电(dian)(dian)转换(huan)成交流(liu)电(dian)(dian)的设备(bei)。由于(yu)太阳能(neng)电(dian)(dian)池和(he)蓄(xu)电(dian)(dian)池是直流(liu)电(dian)(dian)源，而(er)负(fu)(fu)载是交流(liu)负(fu)(fu)载时(shi)，逆(ni)变器是必不可少的。逆(ni)变器按运行(xing)方式，可分为独立(li)运行(xing)逆(ni)变器和(he)并(bing)网逆(ni)变器。独立(li)运行(xing)逆(ni)变器用于(yu)独立(li)运行(xing)的太阳能(neng)电(dian)(dian)池发电(dian)(dian)系统，为独立(li)负(fu)(fu)载供电(dian)(dian)。光伏(fu)并网逆变(bian)器用(yong)于并(bing)网运(yun)行的太(tai)阳能电(dian)池(chi)发电(dian)系统(tong)。逆(ni)变器按输出波(bo)型可(ke)分为方波(bo)逆(ni)变器和(he)(he)正弦(xian)波(bo)逆(ni)变器。方波(bo)逆(ni)变器电(dian)路简单，造(zao)价(jia)低(di)，但(dan)谐波(bo)分量(liang)大，一般用(yong)于几百瓦以下和(he)(he)对谐波(bo)要求不高的系统(tong)。正弦(xian)波(bo)逆(ni)变器成本高，但(dan)可(ke)以适用(yong)于各种负(fu)载(zai)。
4.5跟踪系统
由于相对于某一个固定地点(dian)(dian)的(de)太(tai)阳(yang)(yang)能(neng)光伏发(fa)(fa)电(dian)(dian)系统，一年春夏秋冬四季、每(mei)天(tian)日升日落，太(tai)阳(yang)(yang)的(de)光照角度时(shi)(shi)时(shi)(shi)刻刻都在(zai)变化，如(ru)果太(tai)阳(yang)(yang)能(neng)电(dian)(dian)池板能(neng)够(gou)时(shi)(shi)刻正对太(tai)阳(yang)(yang)，发(fa)(fa)电(dian)(dian)效率(lv)才(cai)会达到最佳状(zhuang)态。世界上通用(yong)的(de)太(tai)阳(yang)(yang)跟(gen)(gen)踪(zong)控制系统都需要根(gen)据(ju)安(an)放点(dian)(dian)的(de)经纬(wei)度等(deng)信息(xi)计(ji)算一年中的(de)每(mei)一天(tian)的(de)不同时(shi)(shi)刻太(tai)阳(yang)(yang)所(suo)在(zai)的(de)角度，将一年中每(mei)个时(shi)(shi)刻的(de)太(tai)阳(yang)(yang)位(wei)(wei)置(zhi)(zhi)存储到PLC、单(dan)片机(ji)或电(dian)(dian)脑软件中，也就是靠(kao)计(ji)算太(tai)阳(yang)(yang)位(wei)(wei)置(zhi)(zhi)以实现跟(gen)(gen)踪(zong)。采用(yong)的(de)是电(dian)(dian)脑数(shu)据(ju)理(li)论(lun)(lun)，需要地球经纬(wei)度地区的(de)的(de)数(shu)据(ju)和(he)设(she)定，一旦安(an)装(zhuang)，就不便(bian)(bian)移(yi)动(dong)或装(zhuang)拆，每(mei)次(ci)移(yi)动(dong)完就必须(xu)重(zhong)新设(she)定数(shu)据(ju)和(he)调整各个参(can)数(shu)；原理(li)、电(dian)(dian)路(lu)、技术、设(she)备复杂，非专业(ye)人士不能(neng)够(gou)随便(bian)(bian)操(cao)作。把(ba)加装(zhuang)了智(zhi)能(neng)太(tai)阳(yang)(yang)跟(gen)(gen)踪(zong)仪的(de)太(tai)阳(yang)(yang)能(neng)发(fa)(fa)电(dian)(dian)系统安(an)装(zhuang)在(zai)高速行驶的(de)汽(qi)车(che)、火车(che)，以及通讯应(ying)急车(che)、特种军(jun)用(yong)汽(qi)车(che)、军(jun)舰或轮(lun)船上，不论(lun)(lun)系统向(xiang)何方行驶、如(ru)何调头、拐弯(wan)，智(zhi)能(neng)太(tai)阳(yang)(yang)跟(gen)(gen)踪(zong)仪都能(neng)保证设(she)备的(de)要求跟(gen)(gen)踪(zong)部(bu)位(wei)(wei)正对太(tai)阳(yang)(yang)。
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