一、前言

　　開關電源系(xi)(xi)統是(shi)(shi)弱電(dian)(dian)(dian)(dian)控(kong)(kong)(kong)(kong)(kong)制(zhi)(zhi)(zhi)強電(dian)(dian)(dian)(dian)的(de)(de)系(xi)(xi)統。開關(guan)電(dian)(dian)(dian)(dian)源(yuan)系(xi)(xi)統主(zhu)要(yao)可以分為(wei)主(zhu)功(gong)率電(dian)(dian)(dian)(dian)路(lu)(lu)和(he)(he)控(kong)(kong)(kong)(kong)(kong)制(zhi)(zhi)(zhi)電(dian)(dian)(dian)(dian)路(lu)(lu)兩部(bu)分。主(zhu)功(gong)率電(dian)(dian)(dian)(dian)路(lu)(lu)是(shi)(shi)由(you)變(bian)(bian)換(huan)(huan)器(qi)構(gou)成。變(bian)(bian)換(huan)(huan)器(qi)是(shi)(shi)應用功(gong)率半導(dao)體(ti)器(qi)件(jian)，對電(dian)(dian)(dian)(dian)能進行變(bian)(bian)換(huan)(huan)的(de)(de)裝(zhuang)置(zhi)，變(bian)(bian)換(huan)(huan)量包括電(dian)(dian)(dian)(dian)壓、電(dian)(dian)(dian)(dian)流、頻率和(he)(he)波形等方面，以達(da)到電(dian)(dian)(dian)(dian)能更好符(fu)合(he)各種不同用電(dian)(dian)(dian)(dian)設備要(yao)求的(de)(de)目(mu)的(de)(de)。這是(shi)(shi)通(tong)過對功(gong)率半導(dao)體(ti)器(qi)件(jian)的(de)(de)開關(guan)的(de)(de)控(kong)(kong)(kong)(kong)(kong)制(zhi)(zhi)(zhi)來(lai)實現的(de)(de)。因此(ci)主(zhu)功(gong)率電(dian)(dian)(dian)(dian)路(lu)(lu)是(shi)(shi)開關(guan)電(dian)(dian)(dian)(dian)源(yuan)控(kong)(kong)(kong)(kong)(kong)制(zhi)(zhi)(zhi)系(xi)(xi)統中的(de)(de)被(bei)(bei)控(kong)(kong)(kong)(kong)(kong)對象(xiang)，而控(kong)(kong)(kong)(kong)(kong)制(zhi)(zhi)(zhi)功(gong)率半導(dao)體(ti)器(qi)件(jian)的(de)(de)開關(guan)以實現既(ji)定的(de)(de)性能是(shi)(shi)控(kong)(kong)(kong)(kong)(kong)制(zhi)(zhi)(zhi)裝(zhuang)置(zhi)的(de)(de)主(zhu)要(yao)工作。將被(bei)(bei)控(kong)(kong)(kong)(kong)(kong)對象(xiang)和(he)(he)控(kong)(kong)(kong)(kong)(kong)制(zhi)(zhi)(zhi)裝(zhuang)置(zhi)按照(zhao)一定的(de)(de)方式連接起來(lai)，組(zu)成一個有(you)機(ji)的(de)(de)總(zong)體(ti)，就構(gou)成開關(guan)電(dian)(dian)(dian)(dian)源(yuan)的(de)(de)控(kong)(kong)(kong)(kong)(kong)制(zhi)(zhi)(zhi)系(xi)(xi)統，這樣的(de)(de)電(dian)(dian)(dian)(dian)路(lu)(lu)即為(wei)控(kong)(kong)(kong)(kong)(kong)制(zhi)(zhi)(zhi)電(dian)(dian)(dian)(dian)路(lu)(lu)。控(kong)(kong)(kong)(kong)(kong)制(zhi)(zhi)(zhi)系(xi)(xi)統的(de)(de)工作方式有(you)多種，其(qi)中最基本的(de)(de)一種是(shi)(shi)基于反(fan)饋控(kong)(kong)(kong)(kong)(kong)制(zhi)(zhi)(zhi)原理的(de)(de)閉環控(kong)(kong)(kong)(kong)(kong)制(zhi)(zhi)(zhi)系(xi)(xi)統。而大部(bu)分的(de)(de)開關(guan)電(dian)(dian)(dian)(dian)源(yuan)控(kong)(kong)(kong)(kong)(kong)制(zhi)(zhi)(zhi)系(xi)(xi)統是(shi)(shi)閉環控(kong)(kong)(kong)(kong)(kong)制(zhi)(zhi)(zhi)系(xi)(xi)統。

　　二、閉環控制原理

　　通常，我們把(ba)被控(kong)(kong)(kong)量送回到(dao)控(kong)(kong)(kong)制系(xi)統的(de)輸入端(duan)，與參據(ju)量相(xiang)比較產生誤差(cha)信(xin)(xin)號的(de)過程，稱(cheng)為(wei)反饋。若反饋的(de)信(xin)(xin)號是與參據(ju)量相(xiang)減，使得產生的(de)偏差(cha)越來(lai)越小，稱(cheng)為(wei)負反饋。由于引入了被控(kong)(kong)(kong)量的(de)反饋信(xin)(xin)息(xi)，整個控(kong)(kong)(kong)制過程成為(wei)閉合(he)的(de)，因此也稱(cheng)閉環(huan)控(kong)(kong)(kong)制，如圖1所示。

圖1  反饋控制框(kuang)圖

　　三、基本組成

　　控制裝置(zhi)是(shi)由具(ju)有(you)一(yi)定(ding)職(zhi)能的各種基本元器件組成。系(xi)統的元器件按照職(zhi)能分類(lei)主要有(you)以下(xia)幾種：

　　測量(liang)單元：其職能(neng)是檢測被控(kong)制的(de)物理(li)量(liang)。這(zhe)個(ge)被控(kong)量(liang)一般為主功率電(dian)(dian)(dian)路的(de)輸出電(dian)(dian)(dian)壓、主功率電(dian)(dian)(dian)路的(de)輸入電(dian)(dian)(dian)流等。

　　給(gei)(gei)定(ding)單元：其職能(neng)是給(gei)(gei)出與期望的被(bei)控量(liang)相對應的參據量(liang)，即給(gei)(gei)定(ding)量(liang)。在開(kai)關電源(yuan)系統(tong)中，給(gei)(gei)定(ding)量(liang)一(yi)般為直流(liu)常量(liang)或者是交流(liu)正弦量(liang)。

　　比較(jiao)(jiao)單元：其(qi)職能(neng)是將檢(jian)測到(dao)的(de)被控制量(liang)的(de)實(shi)際值(zhi)與參據(ju)量(liang)進(jin)行比較(jiao)(jiao)，求(qiu)出他們之間的(de)偏差。

　　校正單(dan)元：即補償單(dan)元，用(yong)串聯方式或(huo)者反(fan)饋方式（并聯方式）等方式連接(jie)在系(xi)統(tong)(tong)中，以(yi)改善系(xi)統(tong)(tong)的性能。這個補償網(wang)(wang)絡是控(kong)制(zhi)系(xi)統(tong)(tong)的核心部(bu)分(fen)，是決定控(kong)制(zhi)系(xi)統(tong)(tong)性能的關鍵部(bu)分(fen)。可(ke)以(yi)通(tong)過(guo)由電阻、電容(rong)組成的無源(yuan)或(huo)有源(yuan)網(wang)(wang)絡實(shi)現，也可(ke)以(yi)通(tong)過(guo)MCU、DSP這些數字器件輔助實(shi)現。

　　四、外作用類型

　　一般加(jia)在開關電(dian)源系統上的(de)外(wai)作用(yong)(yong)有(you)(you)兩種(zhong)類型：一種(zhong)是有(you)(you)用(yong)(yong)輸(shu)(shu)(shu)入(ru)(ru)，它(ta)決定(ding)系統被控量(liang)的(de)變(bian)化規律，比如給定(ding)量(liang)；一種(zhong)是系統不希望有(you)(you)的(de)外(wai)作用(yong)(yong)，即擾動(dong)，它(ta)破壞有(you)(you)用(yong)(yong)輸(shu)(shu)(shu)入(ru)(ru)對(dui)系統的(de)控制(zhi)。在實際系統中，擾動(dong)是不可避免的(de)。這樣的(de)擾動(dong)包(bao)括(kuo)：主功率電(dian)路輸(shu)(shu)(shu)入(ru)(ru)電(dian)壓的(de)波(bo)動(dong)，主功率電(dian)路輸(shu)(shu)(shu)出電(dian)流的(de)波(bo)動(dong)或者負(fu)載的(de)波(bo)動(dong)，元(yuan)器件參數的(de)溫(wen)度漂移等。

      五、基本控(kong)制方式

　　反饋控(kong)(kong)制(zhi)是(shi)(shi)系統(tong)最基本的控(kong)(kong)制(zhi)方(fang)式，也是(shi)(shi)應用(yong)最廣泛的一種控(kong)(kong)制(zhi)方(fang)式。此(ci)外，還有開環控(kong)(kong)制(zhi)方(fang)式和(he)(he)復合控(kong)(kong)制(zhi)方(fang)式，它們(men)都有著各自的特點和(he)(he)不(bu)同的應用(yong)場合。

　　（1）反饋控制方式

　　如前面所提及(ji)，反饋(kui)(kui)控制(zhi)方式是(shi)按照(zhao)偏差進行控制(zhi)的(de)(de)(de)，其(qi)特點是(shi)不論什么原(yuan)因使被(bei)控量偏離(li)期望值(zhi)而(er)出現偏差時，必定會產生一個相應的(de)(de)(de)控制(zhi)作用去減小或消除(chu)這個偏差，使被(bei)控量與(yu)期望值(zhi)趨于一致(zhi)。可見，按照(zhao)反饋(kui)(kui)控制(zhi)方式設計的(de)(de)(de)控制(zhi)系統，具有(you)抑制(zhi)任何內(nei)、外擾動對(dui)被(bei)控量產生影響的(de)(de)(de)能力，有(you)較高(gao)的(de)(de)(de)穩態精度(du)。

　　如圖(tu)2所示為電(dian)(dian)壓(ya)型控制(zhi)Boost變(bian)換器控制(zhi)框圖(tu)，電(dian)(dian)壓(ya)反(fan)饋(kui)控制(zhi)技術是開(kai)關電(dian)(dian)源系統中經典的(de)反(fan)饋(kui)控制(zhi)方(fang)法。這是60年(nian)代后期開(kai)關穩壓(ya)電(dian)(dian)源剛剛開(kai)始(shi)發(fa)展(zhan)就采用(yong)的(de)第一種控制(zhi)方(fang)法，該方(fang)法與(yu)一些必要的(de)過電(dian)(dian)流保護電(dian)(dian)路相結合，至(zhi)今仍然被廣泛的(de)應(ying)用(yong)。

圖2  電壓型控(kong)(kong)制(zhi) Boost 變換(huan)器控(kong)(kong)制(zhi)框圖

　　（2）開(kai)環控制(zhi)方式

　　開環控(kong)(kong)制(zhi)(zhi)(zhi)方式(shi)是指被控(kong)(kong)裝置與被控(kong)(kong)對象之間只有(you)(you)順向作(zuo)用而沒有(you)(you)反向聯(lian)系(xi)(xi)的(de)控(kong)(kong)制(zhi)(zhi)(zhi)過程(cheng)。按這(zhe)種控(kong)(kong)制(zhi)(zhi)(zhi)方式(shi)組成的(de)控(kong)(kong)制(zhi)(zhi)(zhi)系(xi)(xi)統(tong)(tong)稱為開環控(kong)(kong)制(zhi)(zhi)(zhi)系(xi)(xi)統(tong)(tong)，其(qi)特點是系(xi)(xi)統(tong)(tong)的(de)輸出量(liang)不會對系(xi)(xi)統(tong)(tong)的(de)控(kong)(kong)制(zhi)(zhi)(zhi)作(zuo)用發生影(ying)響。這(zhe)種控(kong)(kong)制(zhi)(zhi)(zhi)方式(shi)也稱為前饋控(kong)(kong)制(zhi)(zhi)(zhi)、順饋控(kong)(kong)制(zhi)(zhi)(zhi)。開環控(kong)(kong)制(zhi)(zhi)(zhi)系(xi)(xi)統(tong)(tong)可(ke)以(yi)由按給(gei)定量(liang)控(kong)(kong)制(zhi)(zhi)(zhi)的(de)控(kong)(kong)制(zhi)(zhi)(zhi)方式(shi)組成，也可(ke)以(yi)由按擾動控(kong)(kong)制(zhi)(zhi)(zhi)的(de)控(kong)(kong)制(zhi)(zhi)(zhi)方式(shi)組成。

　　按給定量(liang)控(kong)(kong)制(zhi)(zhi)(zhi)的(de)(de)開環控(kong)(kong)制(zhi)(zhi)(zhi)系統(tong)，其控(kong)(kong)制(zhi)(zhi)(zhi)作用直接由(you)控(kong)(kong)制(zhi)(zhi)(zhi)系統(tong)的(de)(de)輸入(ru)量(liang)產生，給定一個(ge)輸入(ru)量(liang)，就有(you)一個(ge)輸出量(liang)與(yu)之(zhi)相(xiang)對(dui)應(ying)，控(kong)(kong)制(zhi)(zhi)(zhi)精度完全取決于(yu)控(kong)(kong)制(zhi)(zhi)(zhi)電路(lu)所用的(de)(de)元器件以及主功率電路(lu)的(de)(de)特性(xing)，如圖(tu)3所示(shi)。這種控(kong)(kong)制(zhi)(zhi)(zhi)方式沒有(you)自動修(xiu)正偏差(cha)的(de)(de)能力，抗擾動能力差(cha)。但由(you)于(yu)其結(jie)構簡單(dan)、調整方便、成本低，在精度要求(qiu)不高或擾動影響較小(xiao)的(de)(de)情況下，這種控(kong)(kong)制(zhi)(zhi)(zhi)方式還是(shi)有(you)一定的(de)(de)實用價值。

圖3  按給(gei)定(ding)量控制的開環控制系統(tong)

如圖4所示的(de)(de)(de)采用電(dian)容的(de)(de)(de)開(kai)關功(gong)率(lv)變換(huan)器(qi)，一般為多級變換(huan)電(dian)路(lu)中的(de)(de)(de)其(qi)中一級，通常采用開(kai)環控制(zhi)，效率(lv)和(he)功(gong)率(lv)密度(du)較高，容易實現開(kai)關，具(ju)有(you)廣泛的(de)(de)(de)應用前景。

圖4  開環(huan)控(kong)制的開關電容功率(lv)變換器

　　按擾(rao)動(dong)控(kong)制(zhi)的開環控(kong)制(zhi)系統，是利(li)用可測量(liang)的擾(rao)動(dong)量(liang)，產(chan)生一(yi)種補償(chang)作用，以減少或抵(di)消擾(rao)動(dong)對(dui)輸出(chu)量(liang)的影(ying)響，如圖(tu)5所(suo)示。這種控(kong)制(zhi)方(fang)式直接從擾(rao)動(dong)取得(de)信息，并據此(ci)改變(bian)被控(kong)量(liang)，因此(ci)其抗擾(rao)動(dong)性好，控(kong)制(zhi)精(jing)度(du)也較高，但它只(zhi)適(shi)用于(yu)擾(rao)動(dong)是可以測量(liang)的場合(he)，而且一(yi)個(ge)補償(chang)裝置(zhi)只(zhi)能補償(chang)一(yi)個(ge)擾(rao)動(dong)因素，對(dui)其余擾(rao)動(dong)均不起補償(chang)作用。

圖5  按擾動(dong)控制(zhi)的開環控制(zhi)系統

　　如(ru)圖6所示為單(dan)周期控制(zhi)(zhi)Buck變換器控制(zhi)(zhi)框圖，單(dan)周期控制(zhi)(zhi)技(ji)術(shu)實際上(shang)就是一種(zhong)按(an)擾(rao)動控制(zhi)(zhi)的(de)(de)開環控制(zhi)(zhi)系統。它將主功率電(dian)(dian)路的(de)(de)輸(shu)入(ru)電(dian)(dian)壓(ya)(ya)引入(ru)控制(zhi)(zhi)，隨(sui)著輸(shu)入(ru)電(dian)(dian)壓(ya)(ya)的(de)(de)變化，得到不同的(de)(de)占空度，使得主功率電(dian)(dian)路的(de)(de)輸(shu)出電(dian)(dian)壓(ya)(ya)跟(gen)隨(sui)給定量(liang)。理論上(shang)這種(zhong)控制(zhi)(zhi)技(ji)術(shu)完(wan)全抵(di)制(zhi)(zhi)了(le)主功率電(dian)(dian)路的(de)(de)輸(shu)出電(dian)(dian)壓(ya)(ya)擾(rao)動，但是對負載的(de)(de)擾(rao)動卻無能(neng)為力。

圖6  單(dan)周期控(kong)制 Buck 變換器控(kong)制框圖

 （3）復(fu)合控制(zhi)方(fang)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(suo)(suo)示為具(ju)有輸(shu)入(ru)電壓(ya)(ya)(ya)前饋(kui)(kui)(kui)的(de)(de)平(ping)(ping)均電流(liu)(liu)(liu)控(kong)制(zhi)(zhi)Boost變(bian)換器(qi)(qi)的(de)(de)PFC控(kong)制(zhi)(zhi)框圖，這種(zhong)控(kong)制(zhi)(zhi)方(fang)法為雙環(huan)(huan)反饋(kui)(kui)(kui)的(de)(de)控(kong)制(zhi)(zhi)方(fang)法，外環(huan)(huan)為母線(xian)電壓(ya)(ya)(ya)平(ping)(ping)均值(zhi)控(kong)制(zhi)(zhi)環(huan)(huan)，內(nei)環(huan)(huan)為輸(shu)入(ru)電流(liu)(liu)(liu)控(kong)制(zhi)(zhi)環(huan)(huan)。該控(kong)制(zhi)(zhi)方(fang)法將輸(shu)出(chu)電壓(ya)(ya)(ya)的(de)(de)平(ping)(ping)均值(zhi)作為反饋(kui)(kui)(kui)與基準(zhun)(zhun)比(bi)(bi)較(jiao)，產(chan)(chan)生的(de)(de)誤差信(xin)(xin)號經(jing)由(you)電壓(ya)(ya)(ya)補(bu)償(chang)(chang)器(qi)(qi)進(jin)行調(diao)節(jie)。產(chan)(chan)生的(de)(de)信(xin)(xin)號與輸(shu)入(ru)電壓(ya)(ya)(ya)有效值(zhi)一起，控(kong)制(zhi)(zhi)正弦波基準(zhun)(zhun)的(de)(de)幅值(zhi)。再(zai)將輸(shu)入(ru)電流(liu)(liu)(liu)作為反饋(kui)(kui)(kui)與正弦波基準(zhun)(zhun)進(jin)行比(bi)(bi)較(jiao)，產(chan)(chan)生的(de)(de)誤差信(xin)(xin)號經(jing)由(you)電流(liu)(liu)(liu)補(bu)償(chang)(chang)器(qi)(qi)進(jin)行調(diao)節(jie)產(chan)(chan)生調(diao)制(zhi)(zhi)信(xin)(xin)號，再(zai)將該調(diao)制(zhi)(zhi)信(xin)(xin)號與載波比(bi)(bi)較(jiao)得到控(kong)制(zhi)(zhi)信(xin)(xin)號，得到所(suo)(suo)需的(de)(de)控(kong)制(zhi)(zhi)信(xin)(xin)號，外環(huan)(huan)的(de)(de)作用，主(zhu)要控(kong)制(zhi)(zhi)輸(shu)出(chu)電壓(ya)(ya)(ya)，內(nei)環(huan)(huan)主(zhu)要控(kong)制(zhi)(zhi)輸(shu)入(ru)電流(liu)(liu)(liu)的(de)(de)波形，保證輸(shu)入(ru)電流(liu)(liu)(liu)的(de)(de)正弦度。引入(ru)了(le)輸(shu)入(ru)電壓(ya)(ya)(ya)前饋(kui)(kui)(kui)，克(ke)服輸(shu)入(ru)電壓(ya)(ya)(ya)擾(rao)動(dong)對輸(shu)出(chu)電壓(ya)(ya)(ya)的(de)(de)影響。

圖7  具(ju)有輸(shu)入電壓前饋的平均電流控制 Boost 變換器的PFC

　　六、校正方式

　　對控制(zhi)(zhi)系(xi)(xi)(xi)統(tong)(tong)(tong)(tong)(tong)的(de)(de)(de)要求，通(tong)(tong)常以(yi)性能(neng)指標的(de)(de)(de)形式(shi)給出。而(er)為(wei)(wei)了(le)使系(xi)(xi)(xi)統(tong)(tong)(tong)(tong)(tong)獲得(de)滿意的(de)(de)(de)性能(neng)，必須對控制(zhi)(zhi)系(xi)(xi)(xi)統(tong)(tong)(tong)(tong)(tong)進行設計和校(xiao)(xiao)(xiao)正(zheng)(zheng)，也(ye)就是在(zai)系(xi)(xi)(xi)統(tong)(tong)(tong)(tong)(tong)中(zhong)適(shi)當(dang)的(de)(de)(de)位(wei)(wei)置(zhi)加(jia)進適(shi)當(dang)的(de)(de)(de)校(xiao)(xiao)(xiao)正(zheng)(zheng)裝(zhuang)(zhuang)(zhuang)(zhuang)置(zhi)。校(xiao)(xiao)(xiao)正(zheng)(zheng)裝(zhuang)(zhuang)(zhuang)(zhuang)置(zhi)彌補(bu)了(le)原系(xi)(xi)(xi)統(tong)(tong)(tong)(tong)(tong)的(de)(de)(de)性能(neng)缺陷。按照校(xiao)(xiao)(xiao)正(zheng)(zheng)裝(zhuang)(zhuang)(zhuang)(zhuang)置(zhi)在(zai)開(kai)關電(dian)源系(xi)(xi)(xi)統(tong)(tong)(tong)(tong)(tong)中(zhong)的(de)(de)(de)連(lian)(lian)接(jie)(jie)方式(shi)，控制(zhi)(zhi)系(xi)(xi)(xi)統(tong)(tong)(tong)(tong)(tong)的(de)(de)(de)校(xiao)(xiao)(xiao)正(zheng)(zheng)方式(shi)可(ke)以(yi)分為(wei)(wei)串(chuan)聯校(xiao)(xiao)(xiao)正(zheng)(zheng)、反(fan)(fan)饋(kui)(kui)校(xiao)(xiao)(xiao)正(zheng)(zheng)、前(qian)饋(kui)(kui)校(xiao)(xiao)(xiao)正(zheng)(zheng)、復合(he)校(xiao)(xiao)(xiao)正(zheng)(zheng)等。如圖(tu)8所(suo)(suo)示(shi)(shi)為(wei)(wei)系(xi)(xi)(xi)統(tong)(tong)(tong)(tong)(tong)校(xiao)(xiao)(xiao)正(zheng)(zheng)裝(zhuang)(zhuang)(zhuang)(zhuang)置(zhi)位(wei)(wei)置(zhi)示(shi)(shi)意圖(tu)，G（S）為(wei)(wei)被控對象（主功率電(dian)路(lu)）；串(chuan)聯校(xiao)(xiao)(xiao)正(zheng)(zheng)裝(zhuang)(zhuang)(zhuang)(zhuang)置(zhi)一(yi)般(ban)連(lian)(lian)接(jie)(jie)在(zai)G（S）之(zhi)(zhi)前(qian)，串(chuan)接(jie)(jie)與系(xi)(xi)(xi)統(tong)(tong)(tong)(tong)(tong)前(qian)向通(tong)(tong)道(dao)之(zhi)(zhi)中(zhong)，如G1（S）益所(suo)(suo)示(shi)(shi)；反(fan)(fan)饋(kui)(kui)校(xiao)(xiao)(xiao)正(zheng)(zheng)裝(zhuang)(zhuang)(zhuang)(zhuang)置(zhi)連(lian)(lian)接(jie)(jie)在(zai)系(xi)(xi)(xi)統(tong)(tong)(tong)(tong)(tong)局部(bu)反(fan)(fan)饋(kui)(kui)通(tong)(tong)路(lu)之(zhi)(zhi)中(zhong)，如G2（S）位(wei)(wei)置(zhi)所(suo)(suo)示(shi)(shi)；補(bu)償給定(ding)(ding)量的(de)(de)(de)前(qian)饋(kui)(kui)校(xiao)(xiao)(xiao)正(zheng)(zheng)裝(zhuang)(zhuang)(zhuang)(zhuang)置(zhi)接(jie)(jie)在(zai)系(xi)(xi)(xi)統(tong)(tong)(tong)(tong)(tong)給定(ding)(ding)量之(zhi)(zhi)后的(de)(de)(de)前(qian)向通(tong)(tong)道(dao)之(zhi)(zhi)上(shang)，形成前(qian)饋(kui)(kui)校(xiao)(xiao)(xiao)正(zheng)(zheng)通(tong)(tong)路(lu)，如G3（S）位(wei)(wei)置(zhi)所(suo)(suo)示(shi)(shi)，補(bu)償擾(rao)動量的(de)(de)(de)前(qian)饋(kui)(kui)校(xiao)(xiao)(xiao)正(zheng)(zheng)裝(zhuang)(zhuang)(zhuang)(zhuang)置(zhi)接(jie)(jie)在(zai)系(xi)(xi)(xi)統(tong)(tong)(tong)(tong)(tong)可(ke)測(ce)試的(de)(de)(de)振動量之(zhi)(zhi)后，形成一(yi)條(tiao)附加(jia)的(de)(de)(de)通(tong)(tong)道(dao)，如G4（S）位(wei)(wei)置(zhi)所(suo)(suo)示(shi)(shi)。前(qian)饋(kui)(kui)校(xiao)(xiao)(xiao)正(zheng)(zheng)裝(zhuang)(zhuang)(zhuang)(zhuang)置(zhi)可(ke)以(yi)單獨作用與開(kai)環控制(zhi)(zhi)系(xi)(xi)(xi)統(tong)(tong)(tong)(tong)(tong)，也(ye)可(ke)以(yi)作為(wei)(wei)反(fan)(fan)饋(kui)(kui)控制(zhi)(zhi)系(xi)(xi)(xi)統(tong)(tong)(tong)(tong)(tong)的(de)(de)(de)附加(jia)校(xiao)(xiao)(xiao)正(zheng)(zheng)而(er)組成復合(he)校(xiao)(xiao)(xiao)正(zheng)(zheng)控制(zhi)(zhi)系(xi)(xi)(xi)統(tong)(tong)(tong)(tong)(tong)。

圖8  系統(tong)校正裝置位置示意圖

　　七、小結

　　開(kai)關(guan)電(dian)(dian)源系(xi)統通過控制電(dian)(dian)路(lu)對主(zhu)功(gong)率電(dian)(dian)路(lu)的(de)(de)(de)控制實(shi)現電(dian)(dian)能的(de)(de)(de)變換。開(kai)關(guan)電(dian)(dian)源系(xi)統有多種(zhong)控制方(fang)(fang)式(shi)，而控制方(fang)(fang)式(shi)的(de)(de)(de)核(he)心是校正方(fang)(fang)式(shi)。究竟選用哪種(zhong)控制方(fang)(fang)式(shi)，系(xi)統如何(he)校正，取決(jue)于系(xi)統主(zhu)功(gong)率電(dian)(dian)路(lu)的(de)(de)(de)被(bei)控量的(de)(de)(de)性(xing)質(zhi)、抗擾(rao)動(dong)性(xing)要(yao)求、技(ji)術實(shi)現的(de)(de)(de)方(fang)(fang)便(bian)性(xing)、經濟性(xing)要(yao)求、環境(jing)使用條件等因素。