基于DSP的蓄電(dian)池充放電(dian)裝置原(yuan)理

1 引言

在(zai)蓄電(dian)池生產過程中，為了(le)保(bao)證產品質量，常需對成品蓄電(dian)池進(jin)行幾次充(chong)放電(dian)處(chu)(chu)理。傳統充(chong)放電(dian)設備通(tong)常采用(yong)(yong)晶閘管作為整流(liu)(liu)逆(ni)變(bian)功(gong)率器件(jian)。裝(zhuang)置(zhi)比較(jiao)(jiao)復雜，交(jiao)流(liu)(liu)輸進(jin)、輸出的(de)功(gong)率因數(shu)較(jiao)(jiao)低。對電(dian)網的(de)諧(xie)波(bo)污(wu)染也比較(jiao)(jiao)大(da)。為此(ci)，設計(ji)了(le)一種三相SPWM整流(liu)(liu)逆(ni)變(bian)蓄電(dian)池充(chong)放電(dian)裝(zhuang)置(zhi)。它采用(yong)(yong)IGBT作為功(gong)率變(bian)換器件(jian)。交(jiao)流(liu)(liu)側(ce)以精(jing)密鎖相的(de)正弦波(bo)電(dian)流(liu)(liu)實現電(dian)能變(bian)換。可(ke)獲接近(jin)于1的(de)功(gong)率因數(shu)，實現對蓄電(dian)池的(de)充(chong)放電(dian)處(chu)(chu)理，明顯降低了(le)對電(dian)網的(de)諧(xie)波(bo)污(wu)染，滿足(zu)了(le)綠色環保(bao)和(he)節能的(de)設計(ji)要求。

2 系統結構及工作原理

圖(tu)1示出設(she)計(ji)(ji)的(de)蓄(xu)(xu)(xu)電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)生(sheng)產用(yong)(yong)充(chong)(chong)(chong)(chong)放電(dian)(dian)(dian)(dian)(dian)(dian)控(kong)制(zhi)系(xi)統結構。該系(xi)統從原理上可劃分為SPWM雙(shuang)向(xiang)(xiang)逆變(bian)和DC／DC變(bian)換(huan)(huan)充(chong)(chong)(chong)(chong)放電(dian)(dian)(dian)(dian)(dian)(dian)兩個子(zi)(zi)系(xi)統。前(qian)者，在(zai)蓄(xu)(xu)(xu)電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)時(shi)，通(tong)過(guo)(guo)三相PFC升壓(ya)(ya)控(kong)制(zhi)實現(xian)AC／DC變(bian)換(huan)(huan)。將(jiang)交流電(dian)(dian)(dian)(dian)(dian)(dian)網電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)轉(zhuan)(zhuan)換(huan)(huan)成(cheng)蓄(xu)(xu)(xu)電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)所需(xu)的(de)直(zhi)(zhi)流電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)；在(zai)蓄(xu)(xu)(xu)電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)放電(dian)(dian)(dian)(dian)(dian)(dian)時(shi)，通(tong)過(guo)(guo)三相PFC恒壓(ya)(ya)逆變(bian)控(kong)制(zhi)實現(xian)DC／AC變(bian)換(huan)(huan)，將(jiang)蓄(xu)(xu)(xu)電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)開釋的(de)能量(liang)回饋電(dian)(dian)(dian)(dian)(dian)(dian)網。后者，完成(cheng)逆變(bian)直(zhi)(zhi)流電(dian)(dian)(dian)(dian)(dian)(dian)能與蓄(xu)(xu)(xu)電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)電(dian)(dian)(dian)(dian)(dian)(dian)能的(de)轉(zhuan)(zhuan)換(huan)(huan)，以(yi)保(bao)證蓄(xu)(xu)(xu)電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)充(chong)(chong)(chong)(chong)放電(dian)(dian)(dian)(dian)(dian)(dian)過(guo)(guo)程中所要求的(de)電(dian)(dian)(dian)(dian)(dian)(dian)流、電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)和時(shi)間(jian)的(de)控(kong)制(zhi)。各子(zi)(zi)系(xi)統采(cai)(cai)用(yong)(yong)單獨的(de)DSP治(zhi)理，DSP部分以(yi)模板(ban)化(hua)直(zhi)(zhi)插(cha)結構直(zhi)(zhi)接插(cha)進工(gong)(gong)(gong)控(kong)機(ji)的(de)主(zhu)板(ban)，工(gong)(gong)(gong)控(kong)機(ji)承擔(dan)整個系(xi)統的(de)監控(kong)治(zhi)理。系(xi)統由1個逆變(bian)子(zi)(zi)系(xi)統和n個(實驗樣機(ji)設(she)計(ji)(ji)為15個)充(chong)(chong)(chong)(chong)放電(dian)(dian)(dian)(dian)(dian)(dian)子(zi)(zi)系(xi)統組成(cheng)。系(xi)統工(gong)(gong)(gong)作時(shi)，可通(tong)過(guo)(guo)工(gong)(gong)(gong)控(kong)機(ji)編組，使后路(lu)(lu)蓄(xu)(xu)(xu)電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)工(gong)(gong)(gong)作于充(chong)(chong)(chong)(chong)電(dian)(dian)(dian)(dian)(dian)(dian)狀(zhuang)態；n-k路(lu)(lu)工(gong)(gong)(gong)作于放電(dian)(dian)(dian)(dian)(dian)(dian)狀(zhuang)態，這樣蓄(xu)(xu)(xu)電(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)能量(liang)就可直(zhi)(zhi)接在(zai)系(xi)統內(nei)部進行交換(huan)(huan)，從而明顯進步了節(jie)能效果。圖(tu)2示出三相SPWM雙(shuang)向(xiang)(xiang)逆變(bian)電(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)采(cai)(cai)用(yong)(yong)的(de)典型電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)型結構主(zhu)電(dian)(dian)(dian)(dian)(dian)(dian)路(lu)(lu)。

三相反饋電(dian)流(liu)iuf，ivf，iwf用于跟蹤(zong)由DSP產生的電(dian)流(liu)給定信號，從而控制直流(liu)端(duan)電(dian)壓Ud的穩(wen)定；Ud的反饋電(dian)壓Ut的值(zhi)經DSP采樣后通過電(dian)壓調節得到(dao)作用于電(dian)流(liu)內(nei)環的電(dian)流(liu)給定值(zhi)。

圖(tu)(tu)3示出單(dan)(dan)相(xiang)(xiang)(xiang)PWM整流(liu)電路(lu)的相(xiang)(xiang)(xiang)量(liang)圖(tu)(tu)[2]。固然(ran)該系統(tong)采用的是(shi)(shi)三相(xiang)(xiang)(xiang)PWM整流(liu)電路(lu)．但其工作原(yuan)理與單(dan)(dan)相(xiang)(xiang)(xiang)電路(lu)相(xiang)(xiang)(xiang)似，只是(shi)(shi)從單(dan)(dan)相(xiang)(xiang)(xiang)擴展到三相(xiang)(xiang)(xiang)。對(dui)電路(lu)進(jin)(jin)行SPWM控(kong)制(zhi)，在橋的交流(liu)輸(shu)進(jin)(jin)端A，B，C可(ke)(ke)得到三相(xiang)(xiang)(xiang)橋臂的SPWM電壓uiu，uiv，uiw。對(dui)其各(ge)相(xiang)(xiang)(xiang)按圖(tu)(tu)3的相(xiang)(xiang)(xiang)量(liang)圖(tu)(tu)進(jin)(jin)行控(kong)制(zhi)，就可(ke)(ke)使各(ge)相(xiang)(xiang)(xiang)電流(liu)iu，iv，iw為(wei)正(zheng)弦波。且與電壓同(tong)相(xiang)(xiang)(xiang)位(wei)，功率(lv)因數近似為(wei)1。

由此(ci)可知，控(kong)(kong)制(zhi)uiu的(de)(de)大(da)小和相位δ即可控(kong)(kong)制(zhi)電流的(de)(de)大(da)小和流向，從而(er)控(kong)(kong)制(zhi)功率的(de)(de)大(da)小和方向。通過對Ud的(de)(de)恒(heng)壓控(kong)(kong)制(zhi)，實現逆變(bian)器的(de)(de)功率流向，從而(er)實現能量的(de)(de)自動雙向活動。

3 電壓控制器的設計

圖4示出AD／DC逆變(bian)控(kong)(kong)制框(kuang)圖。該系統采(cai)用(yong)電(dian)(dian)(dian)壓(ya)、電(dian)(dian)(dian)流(liu)雙閉環控(kong)(kong)制結構(gou)，其電(dian)(dian)(dian)壓(ya)控(kong)(kong)制對象為(wei)直流(liu)量(liang)；電(dian)(dian)(dian)流(liu)控(kong)(kong)制對象為(wei)交流(liu)量(liang)。電(dian)(dian)(dian)壓(ya)外環采(cai)用(yong)數(shu)字算法(fa)予以實現；電(dian)(dian)(dian)流(liu)內環采(cai)用(yong)模擬電(dian)(dian)(dian)路(lu)予以實現，以確保快(kuai)速進(jin)行電(dian)(dian)(dian)流(liu)控(kong)(kong)制，進(jin)步(bu)系統工作(zuo)的(de)可靠(kao)性。同時(shi)，為(wei)了使誤差電(dian)(dian)(dian)流(liu)與給定相位保持一致。電(dian)(dian)(dian)流(liu)調(diao)節(jie)器采(cai)用(yong)比(bi)例控(kong)(kong)制。

蓄(xu)(xu)電(dian)(dian)(dian)(dian)(dian)池(chi)充電(dian)(dian)(dian)(dian)(dian)時(shi)，輸出電(dian)(dian)(dian)(dian)(dian)壓(ya)Ud低于(yu)給(gei)(gei)定值(zhi)Ud*，則(ze)電(dian)(dian)(dian)(dian)(dian)壓(ya)調節器(qi)輸出正的uc，輸進電(dian)(dian)(dian)(dian)(dian)壓(ya)Uin經(jing)過一個比例因子(zi)Ku后得到(dao)一個與(yu)(yu)Uin同相(xiang)的單(dan)(dan)位(wei)正弦us，uc與(yu)(yu)us的乘積作(zuo)為給(gei)(gei)定電(dian)(dian)(dian)(dian)(dian)流(liu)(liu)i*，與(yu)(yu)Uin同相(xiang)，控制i跟(gen)隨i*，則(ze)能(neng)量就(jiu)以(yi)單(dan)(dan)位(wei)功(gong)(gong)率因數(shu)從(cong)電(dian)(dian)(dian)(dian)(dian)網(wang)流(liu)(liu)向蓄(xu)(xu)電(dian)(dian)(dian)(dian)(dian)池(chi)。此時(shi)，變流(liu)(liu)器(qi)工作(zuo)在整流(liu)(liu)狀(zhuang)態。蓄(xu)(xu)電(dian)(dian)(dian)(dian)(dian)池(chi)放電(dian)(dian)(dian)(dian)(dian)時(shi)，Ud高于(yu)Ud*，則(ze)uc為負(fu)值(zhi)，uc與(yu)(yu)us相(xiang)乘得到(dao)與(yu)(yu)Uin反向的給(gei)(gei)定電(dian)(dian)(dian)(dian)(dian)流(liu)(liu)i*，控制i跟(gen)隨i*，能(neng)量就(jiu)能(neng)以(yi)單(dan)(dan)位(wei)功(gong)(gong)率因數(shu)從(cong)蓄(xu)(xu)電(dian)(dian)(dian)(dian)(dian)池(chi)流(liu)(liu)向電(dian)(dian)(dian)(dian)(dian)網(wang)。此時(shi)，變流(liu)(liu)器(qi)工作(zuo)在逆(ni)變狀(zhuang)態。電(dian)(dian)(dian)(dian)(dian)壓(ya)外(wai)環產生(sheng)輸進給(gei)(gei)定電(dian)(dian)(dian)(dian)(dian)流(liu)(liu)i*，其幅(fu)值(zhi)表(biao)明(ming)了功(gong)(gong)率的大(da)小(xiao)；符號決定了功(gong)(gong)率的流(liu)(liu)向；相(xiang)位(wei)決定了能(neng)量傳(chuan)遞的功(gong)(gong)率因數(shu)。電(dian)(dian)(dian)(dian)(dian)流(liu)(liu)內環使(shi)輸進電(dian)(dian)(dian)(dian)(dian)流(liu)(liu)跟(gen)蹤給(gei)(gei)定，從(cong)而實現可逆(ni)的單(dan)(dan)位(wei)功(gong)(gong)率因數(shu)變換。

系統采用(yong)TMS320LF2407A DSP作(zuo)為主處理器(qi)，因其有豐(feng)富(fu)的(de)(de)(de)外設和較高的(de)(de)(de)運算(suan)(suan)速度。由此可實現(xian)較復雜的(de)(de)(de)控(kong)(kong)制(zhi)及高精(jing)度的(de)(de)(de)數(shu)據處理。在此，通過對PI控(kong)(kong)制(zhi)、IP控(kong)(kong)制(zhi)和變速積分PI控(kong)(kong)制(zhi)三(san)種電(dian)(dian)壓調(diao)節(jie)器(qi)算(suan)(suan)法(fa)的(de)(de)(de)實驗(yan)得出其優(you)劣，從而選擇(ze)最適合該(gai)系統的(de)(de)(de)控(kong)(kong)制(zhi)算(suan)(suan)法(fa)進行(xing)電(dian)(dian)壓調(diao)節(jie)。

(1)PI控制算法和IP控制算法

圖5a示出PI調節器結構圖。由(you)圖可得其傳遞(di)

比(bi)較式(shi)(5)和(he)式(shi)(6)可見，兩種系(xi)(xi)統(tong)(tong)的(de)傳遞(di)(di)函數分母(mu)相同，故IP調(diao)(diao)節(jie)(jie)器(qi)(qi)可持有與PI相同的(de)無靜(jing)差調(diao)(diao)節(jie)(jie)和(he)穩(wen)(wen)定特(te)性(xing)，同時因它在傳遞(di)(di)函數上比(bi)PI少一個零點，因此具有比(bi)PI更(geng)好(hao)的(de)高頻衰減(jian)特(te)性(xing)，輕易(yi)滿足較長采樣周期數字(zi)調(diao)(diao)節(jie)(jie)的(de)穩(wen)(wen)定性(xing)要求(qiu)，能有效(xiao)抑(yi)制混迭現象。系(xi)(xi)統(tong)(tong)實驗證實，采用IP調(diao)(diao)節(jie)(jie)，調(diao)(diao)節(jie)(jie)器(qi)(qi)參數很輕易(yi)整(zheng)定。可使系(xi)(xi)統(tong)(tong)達(da)到穩(wen)(wen)定、無靜(jing)差和(he)很小的(de)超調(diao)(diao)。不過在快速性(xing)方面將有損失(shi)。

(2)變速積分PI控制算法

在(zai)傳統(tong)的PI算法(fa)中，因積(ji)(ji)(ji)(ji)分(fen)(fen)(fen)增(zeng)益Ki為(wei)(wei)常數，在(zai)整個調節過程中，其值不變。但系統(tong)對(dui)積(ji)(ji)(ji)(ji)分(fen)(fen)(fen)的要求是偏差大(da)(da)(da)時，積(ji)(ji)(ji)(ji)分(fen)(fen)(fen)作(zuo)用減弱，否(fou)則會產生(sheng)超調，甚至出現積(ji)(ji)(ji)(ji)分(fen)(fen)(fen)飽和；反(fan)之則加(jia)強，否(fou)則不能(neng)滿(man)足正確性(xing)(xing)的要求。引進變速(su)積(ji)(ji)(ji)(ji)分(fen)(fen)(fen)PI控(kong)制(zhi)(zhi)算法(fa)能(neng)使控(kong)制(zhi)(zhi)性(xing)(xing)能(neng)得(de)以滿(man)足。其基本思路是偏差大(da)(da)(da)時，積(ji)(ji)(ji)(ji)分(fen)(fen)(fen)累(lei)積(ji)(ji)(ji)(ji)速(su)度(du)慢，積(ji)(ji)(ji)(ji)分(fen)(fen)(fen)作(zuo)用弱；偏差小(xiao)時，積(ji)(ji)(ji)(ji)分(fen)(fen)(fen)累(lei)積(ji)(ji)(ji)(ji)速(su)度(du)快(kuai)，積(ji)(ji)(ji)(ji)分(fen)(fen)(fen)作(zuo)用強。為(wei)(wei)此，設置系數f[E(k)]，它是偏差E(k)的函數，當E(k)增(zeng)大(da)(da)(da)時，f[E(k)]減小(xiao)；反(fan)之則增(zeng)大(da)(da)(da)。每次采樣后，用f[E(k)]乘E(k)，再進行累(lei)加(jia)。f[E(k)]與E(k)的關系可(ke)表示為(wei)(wei)：

在該系統(tong)中，采(cai)用簡單的(de)變速(su)積分PI控制(zhi)，取A=32，B=8，當(dang)誤(wu)差(cha)大于(yu)(yu)40時(shi)，系統(tong)相當(dang)于(yu)(yu)采(cai)用純比例調節，因此響應(ying)速(su)度(du)加(jia)快；當(dang)誤(wu)差(cha)小于(yu)(yu)40并減小到8的(de)過(guo)程中，積分作用開始(shi)并逐漸增強，響應(ying)過(guo)程快速(su)平(ping)滑；當(dang)誤(wu)差(cha)小于(yu)(yu)8時(shi)，完全引進積分作用，能快速(su)有效地消除靜差(cha)。該方(fang)法可(ke)有效抑(yi)制(zhi)系統(tong)的(de)超(chao)調，同時(shi)也可(ke)兼顧(gu)系統(tong)的(de)響應(ying)速(su)度(du)。

4 實驗結果

利用(yong)PI，IP和變(bian)(bian)(bian)速(su)(su)(su)積(ji)分(fen)PI數字(zi)電(dian)壓(ya)調(diao)(diao)(diao)(diao)(diao)節(jie)(jie)(jie)(jie)器的(de)逆(ni)變(bian)(bian)(bian)子系統對(dui)(dui)該(gai)設計方(fang)(fang)案(an)進(jin)行了大量實驗(yan)。結果可(ke)見，采(cai)用(yong)變(bian)(bian)(bian)速(su)(su)(su)積(ji)分(fen)PI數字(zi)電(dian)壓(ya)調(diao)(diao)(diao)(diao)(diao)節(jie)(jie)(jie)(jie)器的(de)綜合性(xing)能優(you)于(yu)前兩(liang)種算(suan)(suan)法。圖6示出(chu)采(cai)用(yong)PI調(diao)(diao)(diao)(diao)(diao)節(jie)(jie)(jie)(jie)、IP調(diao)(diao)(diao)(diao)(diao)節(jie)(jie)(jie)(jie)，以及(ji)變(bian)(bian)(bian)速(su)(su)(su)積(ji)分(fen)PI調(diao)(diao)(diao)(diao)(diao)節(jie)(jie)(jie)(jie)時(shi)用(yong)100M-Tektronix TDS220存儲示波器獲取的(de)一組直流母線(xian)電(dian)壓(ya)Ud的(de)實驗(yan)對(dui)(dui)比(bi)波形。逆(ni)變(bian)(bian)(bian)器起動(dong)時(shi)Ud由150V升(sheng)至200V。由圖6可(ke)見。3種調(diao)(diao)(diao)(diao)(diao)節(jie)(jie)(jie)(jie)器在(zai)無(wu)靜差調(diao)(diao)(diao)(diao)(diao)節(jie)(jie)(jie)(jie)方(fang)(fang)面的(de)性(xing)能相同，而IP的(de)上升(sheng)時(shi)間明顯大于(yu)另外兩(liang)種算(suan)(suan)法；在(zai)抑制超(chao)調(diao)(diao)(diao)(diao)(diao)及(ji)高(gao)頻噪(zao)聲(sheng)誘發振(zhen)蕩方(fang)(fang)面，變(bian)(bian)(bian)速(su)(su)(su)積(ji)分(fen)PI法有(you)著(zhu)明顯的(de)上風(feng)，PI系統的(de)起動(dong)超(chao)調(diao)(diao)(diao)(diao)(diao)超(chao)過20V，IP系統的(de)超(chao)調(diao)(diao)(diao)(diao)(diao)不到10V，而變(bian)(bian)(bian)速(su)(su)(su)積(ji)分(fen)PI系統則(ze)無(wu)超(chao)調(diao)(diao)(diao)(diao)(diao)。無(wu)振(zhen)蕩，能很快進(jin)進(jin)穩定(ding)狀態：在(zai)抗干擾性(xing)能方(fang)(fang)面，變(bian)(bian)(bian)速(su)(su)(su)積(ji)分(fen)PI系統也具有(you)同樣的(de)特(te)點(dian)。

5 結論

先容(rong)的(de)(de)(de)逆變器采(cai)用了直流母線電(dian)壓(ya)的(de)(de)(de)恒(heng)壓(ya)數字調節(jie)(jie)，可(ke)方便(bian)地實(shi)現電(dian)網能量和蓄(xu)(xu)電(dian)池(chi)能量的(de)(de)(de)雙(shuang)向活動，精密鎖相的(de)(de)(de)SPWM控(kong)(kong)制(zhi)(zhi)(zhi)可(ke)獲得(de)接近于(yu)1的(de)(de)(de)功(gong)率因數，理論(lun)分(fen)析和系(xi)(xi)統(tong)實(shi)驗表明，在(zai)DSP控(kong)(kong)制(zhi)(zhi)(zhi)采(cai)樣周期即是(shi)交(jiao)流電(dian)源周期的(de)(de)(de)交(jiao)流控(kong)(kong)制(zhi)(zhi)(zhi)系(xi)(xi)統(tong)中(zhong)，采(cai)用變速積分(fen)PI調節(jie)(jie)更易(yi)獲得(de)小超調、無振(zhen)蕩、無靜差的(de)(de)(de)控(kong)(kong)制(zhi)(zhi)(zhi)性能指標。該設計系(xi)(xi)統(tong)可(ke)攜帶15路(lu)3A蓄(xu)(xu)電(dian)池(chi)組(zu)(每組(zu)12V蓄(xu)(xu)電(dian)池(chi)15節(jie)(jie)串聯)進(jin)行充放(fang)電(dian)子系(xi)(xi)統(tong)工作，每路(lu)工作由工控(kong)(kong)機(ji)編程(cheng)獨立控(kong)(kong)制(zhi)(zhi)(zhi)。通(tong)過對(dui)充電(dian)組(zu)和放(fang)電(dian)組(zu)的(de)(de)(de)公(gong)道配(pei)置(zhi)，可(ke)獲得(de)明顯(xian)的(de)(de)(de)節(jie)(jie)能效果。