一、前言

　　開關電源系(xi)統(tong)是(shi)弱電(dian)控(kong)(kong)制(zhi)(zhi)強(qiang)電(dian)的(de)(de)(de)(de)系(xi)統(tong)。開(kai)關(guan)電(dian)源(yuan)系(xi)統(tong)主(zhu)(zhu)要(yao)可以(yi)分(fen)(fen)為主(zhu)(zhu)功率(lv)電(dian)路(lu)和控(kong)(kong)制(zhi)(zhi)電(dian)路(lu)兩部分(fen)(fen)。主(zhu)(zhu)功率(lv)電(dian)路(lu)是(shi)由變換(huan)器(qi)(qi)構成。變換(huan)器(qi)(qi)是(shi)應用(yong)功率(lv)半導(dao)體(ti)(ti)器(qi)(qi)件，對(dui)(dui)電(dian)能(neng)進行(xing)變換(huan)的(de)(de)(de)(de)裝置(zhi)，變換(huan)量包括電(dian)壓、電(dian)流、頻率(lv)和波形等方面，以(yi)達到電(dian)能(neng)更好符(fu)合(he)各種不同用(yong)電(dian)設備(bei)要(yao)求的(de)(de)(de)(de)目的(de)(de)(de)(de)。這是(shi)通過對(dui)(dui)功率(lv)半導(dao)體(ti)(ti)器(qi)(qi)件的(de)(de)(de)(de)開(kai)關(guan)的(de)(de)(de)(de)控(kong)(kong)制(zhi)(zhi)來實現的(de)(de)(de)(de)。因(yin)此主(zhu)(zhu)功率(lv)電(dian)路(lu)是(shi)開(kai)關(guan)電(dian)源(yuan)控(kong)(kong)制(zhi)(zhi)系(xi)統(tong)中(zhong)的(de)(de)(de)(de)被(bei)(bei)控(kong)(kong)對(dui)(dui)象(xiang)，而控(kong)(kong)制(zhi)(zhi)功率(lv)半導(dao)體(ti)(ti)器(qi)(qi)件的(de)(de)(de)(de)開(kai)關(guan)以(yi)實現既定的(de)(de)(de)(de)性能(neng)是(shi)控(kong)(kong)制(zhi)(zhi)裝置(zhi)的(de)(de)(de)(de)主(zhu)(zhu)要(yao)工作。將(jiang)被(bei)(bei)控(kong)(kong)對(dui)(dui)象(xiang)和控(kong)(kong)制(zhi)(zhi)裝置(zhi)按照一定的(de)(de)(de)(de)方式連接(jie)起(qi)來，組成一個(ge)有機的(de)(de)(de)(de)總體(ti)(ti)，就(jiu)構成開(kai)關(guan)電(dian)源(yuan)的(de)(de)(de)(de)控(kong)(kong)制(zhi)(zhi)系(xi)統(tong)，這樣的(de)(de)(de)(de)電(dian)路(lu)即為控(kong)(kong)制(zhi)(zhi)電(dian)路(lu)。控(kong)(kong)制(zhi)(zhi)系(xi)統(tong)的(de)(de)(de)(de)工作方式有多種，其中(zhong)最基本的(de)(de)(de)(de)一種是(shi)基于反(fan)饋(kui)控(kong)(kong)制(zhi)(zhi)原(yuan)理的(de)(de)(de)(de)閉環控(kong)(kong)制(zhi)(zhi)系(xi)統(tong)。而大(da)部分(fen)(fen)的(de)(de)(de)(de)開(kai)關(guan)電(dian)源(yuan)控(kong)(kong)制(zhi)(zhi)系(xi)統(tong)是(shi)閉環控(kong)(kong)制(zhi)(zhi)系(xi)統(tong)。

　　二、閉環控制原理

　　通常(chang)，我們把被控(kong)量送(song)回到控(kong)制系統(tong)的輸(shu)入端，與參(can)據(ju)(ju)量相比較(jiao)產生(sheng)誤(wu)差(cha)信(xin)號的過(guo)程(cheng)，稱為(wei)反(fan)饋。若反(fan)饋的信(xin)號是與參(can)據(ju)(ju)量相減，使得(de)產生(sheng)的偏(pian)差(cha)越來(lai)越小，稱為(wei)負反(fan)饋。由于引入了被控(kong)量的反(fan)饋信(xin)息，整個控(kong)制過(guo)程(cheng)成為(wei)閉合(he)的，因此也稱閉環控(kong)制，如圖1所示。

圖1  反(fan)饋控(kong)制框圖

　　三、基本組成

　　控制裝置是由(you)具有一定職能的各種基(ji)本元(yuan)(yuan)器件組成。系統的元(yuan)(yuan)器件按照職能分類主要(yao)有以下幾種：

　　測量單元：其職(zhi)能(neng)是檢測被(bei)控制的(de)物(wu)理量。這個被(bei)控量一般為主功(gong)率電(dian)(dian)路(lu)的(de)輸(shu)(shu)出電(dian)(dian)壓、主功(gong)率電(dian)(dian)路(lu)的(de)輸(shu)(shu)入電(dian)(dian)流等(deng)。

　　給(gei)定單元：其(qi)職能是(shi)給(gei)出與(yu)期望的被控量相對應的參據(ju)量，即給(gei)定量。在開關電源系(xi)統中，給(gei)定量一般為直流常量或者是(shi)交流正(zheng)弦量。

　　比較(jiao)單元：其職能是將(jiang)檢測到的被控(kong)制量的實際值與參據量進行比較(jiao)，求出他們之間的偏差。

　　校正單元(yuan)：即(ji)補償(chang)單元(yuan)，用串聯方式或者反饋方式（并聯方式）等方式連接在系(xi)統中，以(yi)(yi)改善(shan)系(xi)統的性能。這個補償(chang)網(wang)絡(luo)是(shi)控制系(xi)統的核心(xin)部(bu)分，是(shi)決(jue)定控制系(xi)統性能的關(guan)鍵部(bu)分。可以(yi)(yi)通過(guo)由(you)電阻、電容組成(cheng)的無源或有源網(wang)絡(luo)實現(xian)，也可以(yi)(yi)通過(guo)MCU、DSP這些(xie)數字器件輔助實現(xian)。

　　四、外作用類型

　　一般(ban)加(jia)在(zai)開關電源系統(tong)(tong)上(shang)的(de)(de)外作用(yong)有(you)兩種類型：一種是有(you)用(yong)輸入，它(ta)(ta)決定系統(tong)(tong)被控(kong)量的(de)(de)變化規律(lv)，比如給定量；一種是系統(tong)(tong)不希望有(you)的(de)(de)外作用(yong)，即(ji)擾動(dong)，它(ta)(ta)破壞有(you)用(yong)輸入對系統(tong)(tong)的(de)(de)控(kong)制。在(zai)實際(ji)系統(tong)(tong)中(zhong)，擾動(dong)是不可(ke)避免的(de)(de)。這樣的(de)(de)擾動(dong)包(bao)括(kuo)：主功率(lv)電路(lu)輸入電壓的(de)(de)波(bo)動(dong)，主功率(lv)電路(lu)輸出電流的(de)(de)波(bo)動(dong)或者負載的(de)(de)波(bo)動(dong)，元器件參數的(de)(de)溫度(du)漂移等。

      五、基本控制方式(shi)

　　反饋控(kong)制是系統最(zui)基本的(de)控(kong)制方式，也是應用(yong)最(zui)廣泛的(de)一種控(kong)制方式。此(ci)外，還有(you)開環控(kong)制方式和(he)復(fu)合控(kong)制方式，它們都有(you)著各自的(de)特點和(he)不同的(de)應用(yong)場合。

　　（1）反饋(kui)控制方式

　　如前面所提(ti)及，反饋控(kong)制(zhi)方(fang)式是(shi)按照(zhao)偏差(cha)(cha)進(jin)行控(kong)制(zhi)的，其(qi)特點是(shi)不(bu)論什(shen)么原(yuan)因(yin)使被(bei)(bei)控(kong)量(liang)偏離期(qi)(qi)望值而出現偏差(cha)(cha)時，必定(ding)會(hui)產(chan)生一個(ge)相應的控(kong)制(zhi)作用(yong)去減(jian)小或消(xiao)除這個(ge)偏差(cha)(cha)，使被(bei)(bei)控(kong)量(liang)與期(qi)(qi)望值趨(qu)于一致(zhi)。可(ke)見，按照(zhao)反饋控(kong)制(zhi)方(fang)式設計的控(kong)制(zhi)系統，具有抑制(zhi)任(ren)何內、外擾動對被(bei)(bei)控(kong)量(liang)產(chan)生影(ying)響(xiang)的能力，有較高的穩態精度。

　　如圖(tu)(tu)2所示為(wei)電(dian)壓型控制Boost變換器控制框圖(tu)(tu)，電(dian)壓反(fan)饋控制技術是(shi)開關電(dian)源系統(tong)中經(jing)典(dian)的反(fan)饋控制方法(fa)。這是(shi)60年代后期開關穩(wen)壓電(dian)源剛剛開始發展(zhan)就采用的第一種控制方法(fa)，該方法(fa)與一些必要的過電(dian)流保護(hu)電(dian)路相結合，至今仍然被廣泛的應用。

圖(tu)2  電壓型(xing)控(kong)制 Boost 變換(huan)器控(kong)制框圖(tu)

　　（2）開環控制(zhi)方式

　　開環控(kong)(kong)(kong)制(zhi)(zhi)(zhi)方(fang)式(shi)(shi)是(shi)指被控(kong)(kong)(kong)裝置(zhi)與被控(kong)(kong)(kong)對(dui)象之(zhi)間只有(you)順向(xiang)(xiang)作(zuo)用(yong)而沒有(you)反向(xiang)(xiang)聯(lian)系的(de)(de)(de)控(kong)(kong)(kong)制(zhi)(zhi)(zhi)過程。按(an)這種控(kong)(kong)(kong)制(zhi)(zhi)(zhi)方(fang)式(shi)(shi)組(zu)成(cheng)(cheng)的(de)(de)(de)控(kong)(kong)(kong)制(zhi)(zhi)(zhi)系統(tong)稱(cheng)為開環控(kong)(kong)(kong)制(zhi)(zhi)(zhi)系統(tong)，其特(te)點是(shi)系統(tong)的(de)(de)(de)輸(shu)出量不會對(dui)系統(tong)的(de)(de)(de)控(kong)(kong)(kong)制(zhi)(zhi)(zhi)作(zuo)用(yong)發(fa)生影響。這種控(kong)(kong)(kong)制(zhi)(zhi)(zhi)方(fang)式(shi)(shi)也稱(cheng)為前饋控(kong)(kong)(kong)制(zhi)(zhi)(zhi)、順饋控(kong)(kong)(kong)制(zhi)(zhi)(zhi)。開環控(kong)(kong)(kong)制(zhi)(zhi)(zhi)系統(tong)可以由按(an)給定量控(kong)(kong)(kong)制(zhi)(zhi)(zhi)的(de)(de)(de)控(kong)(kong)(kong)制(zhi)(zhi)(zhi)方(fang)式(shi)(shi)組(zu)成(cheng)(cheng)，也可以由按(an)擾(rao)動控(kong)(kong)(kong)制(zhi)(zhi)(zhi)的(de)(de)(de)控(kong)(kong)(kong)制(zhi)(zhi)(zhi)方(fang)式(shi)(shi)組(zu)成(cheng)(cheng)。

　　按給定(ding)量控制(zhi)的(de)(de)開環(huan)控制(zhi)系統，其控制(zhi)作用直接(jie)由(you)控制(zhi)系統的(de)(de)輸入量產生，給定(ding)一個(ge)輸入量，就(jiu)有一個(ge)輸出(chu)量與之(zhi)相對應，控制(zhi)精度完(wan)全取決于(yu)控制(zhi)電路(lu)所(suo)用的(de)(de)元器件以(yi)及(ji)主功率電路(lu)的(de)(de)特性，如圖3所(suo)示。這(zhe)種控制(zhi)方(fang)式沒有自動修正偏差(cha)的(de)(de)能力，抗擾(rao)動能力差(cha)。但由(you)于(yu)其結構簡單、調整方(fang)便、成本低，在精度要求不高或擾(rao)動影(ying)響較小的(de)(de)情況(kuang)下，這(zhe)種控制(zhi)方(fang)式還是有一定(ding)的(de)(de)實用價值。

圖3  按(an)給定量(liang)控制的(de)開環控制系(xi)統

如(ru)圖(tu)4所示(shi)的(de)采用(yong)電容的(de)開(kai)關(guan)功率(lv)(lv)變換(huan)(huan)器(qi)，一(yi)(yi)般為多(duo)級(ji)變換(huan)(huan)電路中的(de)其中一(yi)(yi)級(ji)，通常采用(yong)開(kai)環控(kong)制(zhi)，效率(lv)(lv)和功率(lv)(lv)密度較高，容易實(shi)現開(kai)關(guan)，具有廣泛的(de)應用(yong)前景。

圖4  開環控(kong)制的開關電(dian)容功率變(bian)換(huan)器(qi)

　　按擾(rao)動(dong)(dong)(dong)控(kong)制(zhi)的(de)開環(huan)控(kong)制(zhi)系統，是利(li)用可測量(liang)的(de)擾(rao)動(dong)(dong)(dong)量(liang)，產生一種(zhong)補(bu)償(chang)(chang)(chang)作(zuo)用，以減少或抵(di)消擾(rao)動(dong)(dong)(dong)對(dui)輸出量(liang)的(de)影響，如(ru)圖5所示(shi)。這種(zhong)控(kong)制(zhi)方式直接(jie)從(cong)擾(rao)動(dong)(dong)(dong)取(qu)得信息，并據此改變(bian)被控(kong)量(liang)，因(yin)此其(qi)抗擾(rao)動(dong)(dong)(dong)性好，控(kong)制(zhi)精度也較高，但它只適用于擾(rao)動(dong)(dong)(dong)是可以測量(liang)的(de)場合，而且一個(ge)補(bu)償(chang)(chang)(chang)裝置只能補(bu)償(chang)(chang)(chang)一個(ge)擾(rao)動(dong)(dong)(dong)因(yin)素，對(dui)其(qi)余擾(rao)動(dong)(dong)(dong)均不起補(bu)償(chang)(chang)(chang)作(zuo)用。

圖5  按擾動控(kong)制的開環控(kong)制系統

　　如(ru)圖6所示為單(dan)周期控(kong)制Buck變(bian)(bian)換器(qi)控(kong)制框圖，單(dan)周期控(kong)制技術實際上就(jiu)是一種按(an)擾動(dong)控(kong)制的(de)開環控(kong)制系統。它將主功率(lv)(lv)電(dian)(dian)路的(de)輸(shu)入(ru)(ru)電(dian)(dian)壓(ya)(ya)引入(ru)(ru)控(kong)制，隨著(zhu)輸(shu)入(ru)(ru)電(dian)(dian)壓(ya)(ya)的(de)變(bian)(bian)化，得到不(bu)同的(de)占(zhan)空度，使得主功率(lv)(lv)電(dian)(dian)路的(de)輸(shu)出電(dian)(dian)壓(ya)(ya)跟隨給定量。理論上這種控(kong)制技術完全抵制了主功率(lv)(lv)電(dian)(dian)路的(de)輸(shu)出電(dian)(dian)壓(ya)(ya)擾動(dong)，但(dan)是對負載的(de)擾動(dong)卻無能為力。

圖6  單周期控(kong)制 Buck 變換器(qi)控(kong)制框圖

 （3）復合控(kong)制(zhi)方式

　　開環控制方式在技術上較反饋控制方式簡單，且對激勵響應快，但是僅僅只采用按給定量控制的前饋控制方式來控制，系統控制精度不高。而按擾動控制的開環控制系統只適用于擾動可以測量的場合。因此，比較合理的一種控制方式是把開環控制方式與反饋控制方式結合起來。這種控制方式稱為復合控制。利用控制系統的給定量，產生一種補償作用，使得被控量更好的跟隨給定量。另外，對主要擾動采用適當的補償裝置來實現擾動控制。同時，再組成反饋控制系統實現按偏差控制，以消除其余擾動產生的偏差。這樣，系統的主要外作用已被補償，反饋控制系統比較容易設計，控制效果也會更好。這種將前饋控制和反饋控制相結合的控制方式稱為復合控制。
如圖7所示為(wei)具有輸(shu)(shu)(shu)(shu)入(ru)電(dian)(dian)(dian)(dian)壓(ya)前饋的(de)(de)(de)(de)平均電(dian)(dian)(dian)(dian)流控(kong)(kong)(kong)(kong)(kong)(kong)制(zhi)(zhi)(zhi)Boost變換器的(de)(de)(de)(de)PFC控(kong)(kong)(kong)(kong)(kong)(kong)制(zhi)(zhi)(zhi)框圖，這種控(kong)(kong)(kong)(kong)(kong)(kong)制(zhi)(zhi)(zhi)方法為(wei)雙環反饋的(de)(de)(de)(de)控(kong)(kong)(kong)(kong)(kong)(kong)制(zhi)(zhi)(zhi)方法，外環為(wei)母線電(dian)(dian)(dian)(dian)壓(ya)平均值控(kong)(kong)(kong)(kong)(kong)(kong)制(zhi)(zhi)(zhi)環，內(nei)環為(wei)輸(shu)(shu)(shu)(shu)入(ru)電(dian)(dian)(dian)(dian)流控(kong)(kong)(kong)(kong)(kong)(kong)制(zhi)(zhi)(zhi)環。該控(kong)(kong)(kong)(kong)(kong)(kong)制(zhi)(zhi)(zhi)方法將(jiang)輸(shu)(shu)(shu)(shu)出電(dian)(dian)(dian)(dian)壓(ya)的(de)(de)(de)(de)平均值作為(wei)反饋與(yu)基(ji)(ji)準(zhun)(zhun)比較(jiao)，產(chan)(chan)生(sheng)的(de)(de)(de)(de)誤差信(xin)(xin)號(hao)(hao)(hao)經由電(dian)(dian)(dian)(dian)壓(ya)補償器進行調節。產(chan)(chan)生(sheng)的(de)(de)(de)(de)信(xin)(xin)號(hao)(hao)(hao)與(yu)輸(shu)(shu)(shu)(shu)入(ru)電(dian)(dian)(dian)(dian)壓(ya)有效值一起，控(kong)(kong)(kong)(kong)(kong)(kong)制(zhi)(zhi)(zhi)正弦波(bo)基(ji)(ji)準(zhun)(zhun)的(de)(de)(de)(de)幅(fu)值。再將(jiang)輸(shu)(shu)(shu)(shu)入(ru)電(dian)(dian)(dian)(dian)流作為(wei)反饋與(yu)正弦波(bo)基(ji)(ji)準(zhun)(zhun)進行比較(jiao)，產(chan)(chan)生(sheng)的(de)(de)(de)(de)誤差信(xin)(xin)號(hao)(hao)(hao)經由電(dian)(dian)(dian)(dian)流補償器進行調節產(chan)(chan)生(sheng)調制(zhi)(zhi)(zhi)信(xin)(xin)號(hao)(hao)(hao)，再將(jiang)該調制(zhi)(zhi)(zhi)信(xin)(xin)號(hao)(hao)(hao)與(yu)載波(bo)比較(jiao)得(de)到(dao)控(kong)(kong)(kong)(kong)(kong)(kong)制(zhi)(zhi)(zhi)信(xin)(xin)號(hao)(hao)(hao)，得(de)到(dao)所需(xu)的(de)(de)(de)(de)控(kong)(kong)(kong)(kong)(kong)(kong)制(zhi)(zhi)(zhi)信(xin)(xin)號(hao)(hao)(hao)，外環的(de)(de)(de)(de)作用，主要(yao)控(kong)(kong)(kong)(kong)(kong)(kong)制(zhi)(zhi)(zhi)輸(shu)(shu)(shu)(shu)出電(dian)(dian)(dian)(dian)壓(ya)，內(nei)環主要(yao)控(kong)(kong)(kong)(kong)(kong)(kong)制(zhi)(zhi)(zhi)輸(shu)(shu)(shu)(shu)入(ru)電(dian)(dian)(dian)(dian)流的(de)(de)(de)(de)波(bo)形，保證輸(shu)(shu)(shu)(shu)入(ru)電(dian)(dian)(dian)(dian)流的(de)(de)(de)(de)正弦度。引入(ru)了輸(shu)(shu)(shu)(shu)入(ru)電(dian)(dian)(dian)(dian)壓(ya)前饋，克服輸(shu)(shu)(shu)(shu)入(ru)電(dian)(dian)(dian)(dian)壓(ya)擾(rao)動(dong)對輸(shu)(shu)(shu)(shu)出電(dian)(dian)(dian)(dian)壓(ya)的(de)(de)(de)(de)影(ying)響。

圖(tu)7  具有輸入電(dian)壓前饋的(de)平(ping)均電(dian)流控制 Boost 變(bian)換器(qi)的(de)PFC

　　六、校正方式

　　對(dui)控(kong)(kong)制(zhi)(zhi)系(xi)(xi)統(tong)(tong)(tong)的(de)(de)要求(qiu)，通(tong)常以(yi)性能(neng)指標的(de)(de)形(xing)式給出。而為(wei)(wei)了使系(xi)(xi)統(tong)(tong)(tong)獲得滿意(yi)的(de)(de)性能(neng)，必須對(dui)控(kong)(kong)制(zhi)(zhi)系(xi)(xi)統(tong)(tong)(tong)進(jin)(jin)行(xing)設(she)計和(he)校(xiao)(xiao)正(zheng)(zheng)(zheng)(zheng)(zheng)，也(ye)就是在(zai)(zai)系(xi)(xi)統(tong)(tong)(tong)中適(shi)當的(de)(de)位置(zhi)(zhi)(zhi)加(jia)進(jin)(jin)適(shi)當的(de)(de)校(xiao)(xiao)正(zheng)(zheng)(zheng)(zheng)(zheng)裝(zhuang)置(zhi)(zhi)(zhi)。校(xiao)(xiao)正(zheng)(zheng)(zheng)(zheng)(zheng)裝(zhuang)置(zhi)(zhi)(zhi)彌(mi)補(bu)了原系(xi)(xi)統(tong)(tong)(tong)的(de)(de)性能(neng)缺(que)陷(xian)。按(an)照(zhao)校(xiao)(xiao)正(zheng)(zheng)(zheng)(zheng)(zheng)裝(zhuang)置(zhi)(zhi)(zhi)在(zai)(zai)開關(guan)電(dian)源系(xi)(xi)統(tong)(tong)(tong)中的(de)(de)連(lian)(lian)接方(fang)(fang)式，控(kong)(kong)制(zhi)(zhi)系(xi)(xi)統(tong)(tong)(tong)的(de)(de)校(xiao)(xiao)正(zheng)(zheng)(zheng)(zheng)(zheng)方(fang)(fang)式可(ke)以(yi)分為(wei)(wei)串(chuan)(chuan)聯校(xiao)(xiao)正(zheng)(zheng)(zheng)(zheng)(zheng)、反饋校(xiao)(xiao)正(zheng)(zheng)(zheng)(zheng)(zheng)、前(qian)饋校(xiao)(xiao)正(zheng)(zheng)(zheng)(zheng)(zheng)、復合校(xiao)(xiao)正(zheng)(zheng)(zheng)(zheng)(zheng)等。如(ru)(ru)圖(tu)8所(suo)示(shi)為(wei)(wei)系(xi)(xi)統(tong)(tong)(tong)校(xiao)(xiao)正(zheng)(zheng)(zheng)(zheng)(zheng)裝(zhuang)置(zhi)(zhi)(zhi)位置(zhi)(zhi)(zhi)示(shi)意(yi)圖(tu)，G（S）為(wei)(wei)被控(kong)(kong)對(dui)象（主(zhu)功率電(dian)路）；串(chuan)(chuan)聯校(xiao)(xiao)正(zheng)(zheng)(zheng)(zheng)(zheng)裝(zhuang)置(zhi)(zhi)(zhi)一般連(lian)(lian)接在(zai)(zai)G（S）之前(qian)，串(chuan)(chuan)接與系(xi)(xi)統(tong)(tong)(tong)前(qian)向通(tong)道(dao)之中，如(ru)(ru)G1（S）益所(suo)示(shi)；反饋校(xiao)(xiao)正(zheng)(zheng)(zheng)(zheng)(zheng)裝(zhuang)置(zhi)(zhi)(zhi)連(lian)(lian)接在(zai)(zai)系(xi)(xi)統(tong)(tong)(tong)局(ju)部反饋通(tong)路之中，如(ru)(ru)G2（S）位置(zhi)(zhi)(zhi)所(suo)示(shi)；補(bu)償給定量的(de)(de)前(qian)饋校(xiao)(xiao)正(zheng)(zheng)(zheng)(zheng)(zheng)裝(zhuang)置(zhi)(zhi)(zhi)接在(zai)(zai)系(xi)(xi)統(tong)(tong)(tong)給定量之后的(de)(de)前(qian)向通(tong)道(dao)之上，形(xing)成前(qian)饋校(xiao)(xiao)正(zheng)(zheng)(zheng)(zheng)(zheng)通(tong)路，如(ru)(ru)G3（S）位置(zhi)(zhi)(zhi)所(suo)示(shi)，補(bu)償擾動(dong)(dong)量的(de)(de)前(qian)饋校(xiao)(xiao)正(zheng)(zheng)(zheng)(zheng)(zheng)裝(zhuang)置(zhi)(zhi)(zhi)接在(zai)(zai)系(xi)(xi)統(tong)(tong)(tong)可(ke)測(ce)試(shi)的(de)(de)振動(dong)(dong)量之后，形(xing)成一條附(fu)加(jia)的(de)(de)通(tong)道(dao)，如(ru)(ru)G4（S）位置(zhi)(zhi)(zhi)所(suo)示(shi)。前(qian)饋校(xiao)(xiao)正(zheng)(zheng)(zheng)(zheng)(zheng)裝(zhuang)置(zhi)(zhi)(zhi)可(ke)以(yi)單獨作用(yong)與開環控(kong)(kong)制(zhi)(zhi)系(xi)(xi)統(tong)(tong)(tong)，也(ye)可(ke)以(yi)作為(wei)(wei)反饋控(kong)(kong)制(zhi)(zhi)系(xi)(xi)統(tong)(tong)(tong)的(de)(de)附(fu)加(jia)校(xiao)(xiao)正(zheng)(zheng)(zheng)(zheng)(zheng)而組成復合校(xiao)(xiao)正(zheng)(zheng)(zheng)(zheng)(zheng)控(kong)(kong)制(zhi)(zhi)系(xi)(xi)統(tong)(tong)(tong)。

圖8  系統校正裝(zhuang)置位置示(shi)意圖

　　七、小結

　　開(kai)關電(dian)源(yuan)系(xi)(xi)統通(tong)過(guo)控(kong)制(zhi)電(dian)路對主(zhu)功率電(dian)路的(de)控(kong)制(zhi)實現(xian)電(dian)能的(de)變換。開(kai)關電(dian)源(yuan)系(xi)(xi)統有多種控(kong)制(zhi)方(fang)式(shi)(shi)，而控(kong)制(zhi)方(fang)式(shi)(shi)的(de)核心是校正(zheng)(zheng)方(fang)式(shi)(shi)。究(jiu)竟選用哪種控(kong)制(zhi)方(fang)式(shi)(shi)，系(xi)(xi)統如(ru)何校正(zheng)(zheng)，取(qu)決于系(xi)(xi)統主(zhu)功率電(dian)路的(de)被控(kong)量的(de)性質(zhi)、抗(kang)擾動性要求、技術實現(xian)的(de)方(fang)便(bian)性、經濟(ji)性要求、環境使用條件等因素。