基于DSP的蓄(xu)電池充放電裝置原理

1 引言

在蓄(xu)電(dian)(dian)(dian)池生產過程(cheng)中，為(wei)了保證產品質量，常(chang)(chang)需對(dui)成品蓄(xu)電(dian)(dian)(dian)池進行(xing)幾(ji)次(ci)充(chong)(chong)放電(dian)(dian)(dian)處理。傳統充(chong)(chong)放電(dian)(dian)(dian)設(she)備通常(chang)(chang)采用晶閘(zha)管作(zuo)為(wei)整流(liu)逆(ni)變(bian)功率(lv)(lv)器(qi)件(jian)。裝(zhuang)置(zhi)比較(jiao)復(fu)雜，交(jiao)流(liu)輸進、輸出的功率(lv)(lv)因(yin)數(shu)較(jiao)低。對(dui)電(dian)(dian)(dian)網的諧波污染也比較(jiao)大。為(wei)此，設(she)計(ji)了一種(zhong)三相SPWM整流(liu)逆(ni)變(bian)蓄(xu)電(dian)(dian)(dian)池充(chong)(chong)放電(dian)(dian)(dian)裝(zhuang)置(zhi)。它(ta)采用IGBT作(zuo)為(wei)功率(lv)(lv)變(bian)換器(qi)件(jian)。交(jiao)流(liu)側以(yi)精密鎖相的正(zheng)弦波電(dian)(dian)(dian)流(liu)實現(xian)電(dian)(dian)(dian)能(neng)(neng)變(bian)換。可獲接近于1的功率(lv)(lv)因(yin)數(shu)，實現(xian)對(dui)蓄(xu)電(dian)(dian)(dian)池的充(chong)(chong)放電(dian)(dian)(dian)處理，明顯(xian)降低了對(dui)電(dian)(dian)(dian)網的諧波污染，滿足(zu)了綠色環保和節能(neng)(neng)的設(she)計(ji)要(yao)求(qiu)。

2 系統結構及工作原理

圖(tu)1示(shi)出設計的(de)蓄(xu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)生產用(yong)充(chong)放(fang)(fang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)控(kong)(kong)制系統(tong)(tong)(tong)結構(gou)。該(gai)系統(tong)(tong)(tong)從(cong)原理上可(ke)劃分為SPWM雙向(xiang)逆(ni)(ni)(ni)變(bian)(bian)(bian)和DC／DC變(bian)(bian)(bian)換(huan)充(chong)放(fang)(fang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)兩個子(zi)系統(tong)(tong)(tong)。前者，在蓄(xu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)充(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)時(shi)(shi)，通過三(san)相(xiang)PFC升壓(ya)(ya)控(kong)(kong)制實(shi)現AC／DC變(bian)(bian)(bian)換(huan)。將交流(liu)(liu)(liu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)網電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)轉換(huan)成(cheng)(cheng)蓄(xu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)充(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)所需的(de)直(zhi)流(liu)(liu)(liu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)；在蓄(xu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)放(fang)(fang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)時(shi)(shi)，通過三(san)相(xiang)PFC恒壓(ya)(ya)逆(ni)(ni)(ni)變(bian)(bian)(bian)控(kong)(kong)制實(shi)現DC／AC變(bian)(bian)(bian)換(huan)，將蓄(xu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)開釋的(de)能量回(hui)饋電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)網。后(hou)者，完成(cheng)(cheng)逆(ni)(ni)(ni)變(bian)(bian)(bian)直(zhi)流(liu)(liu)(liu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)能與蓄(xu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)能的(de)轉換(huan)，以保證(zheng)蓄(xu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)充(chong)放(fang)(fang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)過程中所要求的(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)、電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)和時(shi)(shi)間的(de)控(kong)(kong)制。各(ge)子(zi)系統(tong)(tong)(tong)采用(yong)單獨(du)的(de)DSP治理，DSP部分以模板化(hua)直(zhi)插結構(gou)直(zhi)接插進工控(kong)(kong)機的(de)主(zhu)(zhu)板，工控(kong)(kong)機承擔(dan)整(zheng)個系統(tong)(tong)(tong)的(de)監控(kong)(kong)治理。系統(tong)(tong)(tong)由1個逆(ni)(ni)(ni)變(bian)(bian)(bian)子(zi)系統(tong)(tong)(tong)和n個(實(shi)驗樣機設計為15個)充(chong)放(fang)(fang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)子(zi)系統(tong)(tong)(tong)組成(cheng)(cheng)。系統(tong)(tong)(tong)工作(zuo)時(shi)(shi)，可(ke)通過工控(kong)(kong)機編組，使后(hou)路蓄(xu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)工作(zuo)于充(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)狀態；n-k路工作(zuo)于放(fang)(fang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)狀態，這樣蓄(xu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)能量就可(ke)直(zhi)接在系統(tong)(tong)(tong)內(nei)部進行交換(huan)，從(cong)而明顯進步(bu)了節(jie)能效果。圖(tu)2示(shi)出三(san)相(xiang)SPWM雙向(xiang)逆(ni)(ni)(ni)變(bian)(bian)(bian)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路采用(yong)的(de)典型電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)型結構(gou)主(zhu)(zhu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路。

三相反饋電(dian)流(liu)iuf，ivf，iwf用(yong)于(yu)跟蹤由(you)DSP產生(sheng)的(de)電(dian)流(liu)給定信號，從(cong)而控制直流(liu)端電(dian)壓Ud的(de)穩定；Ud的(de)反饋電(dian)壓Ut的(de)值(zhi)經DSP采(cai)樣后通過(guo)電(dian)壓調節得到作用(yong)于(yu)電(dian)流(liu)內環的(de)電(dian)流(liu)給定值(zhi)。

圖3示出單相(xiang)PWM整流電(dian)(dian)(dian)路(lu)的(de)相(xiang)量圖[2]。固然該系統(tong)采(cai)用的(de)是三相(xiang)PWM整流電(dian)(dian)(dian)路(lu)．但(dan)其工(gong)作原理與(yu)(yu)單相(xiang)電(dian)(dian)(dian)路(lu)相(xiang)似(si)，只(zhi)是從單相(xiang)擴展到(dao)三相(xiang)。對電(dian)(dian)(dian)路(lu)進行(xing)SPWM控制，在橋(qiao)的(de)交(jiao)流輸進端A，B，C可得到(dao)三相(xiang)橋(qiao)臂(bei)的(de)SPWM電(dian)(dian)(dian)壓uiu，uiv，uiw。對其各(ge)相(xiang)按圖3的(de)相(xiang)量圖進行(xing)控制，就(jiu)可使各(ge)相(xiang)電(dian)(dian)(dian)流iu，iv，iw為正弦(xian)波。且(qie)與(yu)(yu)電(dian)(dian)(dian)壓同相(xiang)位(wei)，功率(lv)因數近似(si)為1。

由(you)此可知(zhi)，控(kong)制uiu的(de)(de)(de)大(da)小和(he)相位δ即可控(kong)制電流的(de)(de)(de)大(da)小和(he)流向(xiang)(xiang)，從而控(kong)制功率的(de)(de)(de)大(da)小和(he)方向(xiang)(xiang)。通過(guo)對Ud的(de)(de)(de)恒壓控(kong)制，實(shi)現逆變器的(de)(de)(de)功率流向(xiang)(xiang)，從而實(shi)現能量(liang)的(de)(de)(de)自動(dong)雙(shuang)向(xiang)(xiang)活動(dong)。

3 電壓控制器的設計

圖4示出AD／DC逆變控(kong)(kong)制框(kuang)圖。該系統采(cai)用電(dian)(dian)(dian)壓(ya)、電(dian)(dian)(dian)流(liu)(liu)雙閉(bi)環控(kong)(kong)制結構(gou)，其電(dian)(dian)(dian)壓(ya)控(kong)(kong)制對(dui)象(xiang)為(wei)直流(liu)(liu)量(liang)；電(dian)(dian)(dian)流(liu)(liu)控(kong)(kong)制對(dui)象(xiang)為(wei)交流(liu)(liu)量(liang)。電(dian)(dian)(dian)壓(ya)外環采(cai)用數字算法(fa)予以實(shi)現(xian)(xian)；電(dian)(dian)(dian)流(liu)(liu)內環采(cai)用模(mo)擬電(dian)(dian)(dian)路予以實(shi)現(xian)(xian)，以確保快速(su)進(jin)行電(dian)(dian)(dian)流(liu)(liu)控(kong)(kong)制，進(jin)步(bu)系統工作(zuo)的可靠性(xing)。同(tong)時(shi)，為(wei)了使(shi)誤差電(dian)(dian)(dian)流(liu)(liu)與(yu)給定(ding)相位保持一致。電(dian)(dian)(dian)流(liu)(liu)調節(jie)器采(cai)用比例控(kong)(kong)制。

蓄(xu)(xu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池充電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)時，輸(shu)出電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)Ud低于(yu)給(gei)(gei)定(ding)值Ud*，則電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)調(diao)節器(qi)輸(shu)出正(zheng)(zheng)的(de)(de)uc，輸(shu)進(jin)(jin)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)Uin經過一個(ge)比例因子Ku后得(de)到(dao)一個(ge)與Uin同相(xiang)的(de)(de)單位(wei)正(zheng)(zheng)弦us，uc與us的(de)(de)乘(cheng)積作為(wei)給(gei)(gei)定(ding)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)i*，與Uin同相(xiang)，控制i跟(gen)隨(sui)i*，則能量(liang)就以單位(wei)功(gong)率(lv)(lv)因數(shu)(shu)從電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)網(wang)流(liu)向蓄(xu)(xu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池。此時，變(bian)流(liu)器(qi)工作在整流(liu)狀態(tai)。蓄(xu)(xu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池放電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)時，Ud高于(yu)Ud*，則uc為(wei)負(fu)值，uc與us相(xiang)乘(cheng)得(de)到(dao)與Uin反(fan)向的(de)(de)給(gei)(gei)定(ding)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)i*，控制i跟(gen)隨(sui)i*，能量(liang)就能以單位(wei)功(gong)率(lv)(lv)因數(shu)(shu)從蓄(xu)(xu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池流(liu)向電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)網(wang)。此時，變(bian)流(liu)器(qi)工作在逆變(bian)狀態(tai)。電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)外環產生輸(shu)進(jin)(jin)給(gei)(gei)定(ding)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)i*，其(qi)幅值表明了功(gong)率(lv)(lv)的(de)(de)大小；符(fu)號決定(ding)了功(gong)率(lv)(lv)的(de)(de)流(liu)向；相(xiang)位(wei)決定(ding)了能量(liang)傳(chuan)遞的(de)(de)功(gong)率(lv)(lv)因數(shu)(shu)。電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)內環使輸(shu)進(jin)(jin)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)跟(gen)蹤給(gei)(gei)定(ding)，從而實(shi)現(xian)可逆的(de)(de)單位(wei)功(gong)率(lv)(lv)因數(shu)(shu)變(bian)換。

系統采用TMS320LF2407A DSP作為主處(chu)理器，因其(qi)有豐富的(de)(de)外設和(he)較(jiao)高(gao)的(de)(de)運算速度。由此(ci)可實(shi)現較(jiao)復雜的(de)(de)控(kong)(kong)制(zhi)及高(gao)精度的(de)(de)數據處(chu)理。在(zai)此(ci)，通過(guo)對PI控(kong)(kong)制(zhi)、IP控(kong)(kong)制(zhi)和(he)變速積分PI控(kong)(kong)制(zhi)三種電(dian)壓(ya)調節器算法(fa)的(de)(de)實(shi)驗得出其(qi)優劣，從而選擇最適合該系統的(de)(de)控(kong)(kong)制(zhi)算法(fa)進行電(dian)壓(ya)調節。

(1)PI控制算法和IP控制算法

圖(tu)5a示出PI調(diao)節器(qi)結構圖(tu)。由圖(tu)可得其傳遞

比(bi)較(jiao)式(shi)(5)和式(shi)(6)可見，兩(liang)種系統的(de)傳遞函數分母相(xiang)同，故(gu)IP調(diao)節器(qi)可持(chi)有(you)與(yu)PI相(xiang)同的(de)無靜差(cha)調(diao)節和穩定特性(xing)，同時因它在傳遞函數上比(bi)PI少(shao)一個零點，因此具有(you)比(bi)PI更(geng)好的(de)高頻衰(shuai)減特性(xing)，輕易滿(man)足較(jiao)長采樣周期數字調(diao)節的(de)穩定性(xing)要(yao)求(qiu)，能(neng)有(you)效抑制混迭現象。系統實(shi)驗(yan)證實(shi)，采用IP調(diao)節，調(diao)節器(qi)參(can)數很輕易整定。可使(shi)系統達到穩定、無靜差(cha)和很小的(de)超調(diao)。不過在快速性(xing)方面將有(you)損失。

(2)變速積分PI控制算法

在(zai)傳統的(de)PI算法(fa)中(zhong)，因積(ji)(ji)分增(zeng)益Ki為常數(shu)(shu)，在(zai)整個調節過(guo)程中(zhong)，其(qi)值不(bu)(bu)變。但系(xi)(xi)統對積(ji)(ji)分的(de)要求(qiu)(qiu)是(shi)偏(pian)差大(da)時，積(ji)(ji)分作用減(jian)弱，否則(ze)會產生超(chao)調，甚至(zhi)出現積(ji)(ji)分飽和；反之則(ze)加強(qiang)，否則(ze)不(bu)(bu)能(neng)滿足(zu)正確(que)性的(de)要求(qiu)(qiu)。引進變速積(ji)(ji)分PI控制算法(fa)能(neng)使控制性能(neng)得(de)以滿足(zu)。其(qi)基本思路(lu)是(shi)偏(pian)差大(da)時，積(ji)(ji)分累積(ji)(ji)速度(du)慢(man)，積(ji)(ji)分作用弱；偏(pian)差小(xiao)時，積(ji)(ji)分累積(ji)(ji)速度(du)快，積(ji)(ji)分作用強(qiang)。為此，設置系(xi)(xi)數(shu)(shu)f[E(k)]，它是(shi)偏(pian)差E(k)的(de)函數(shu)(shu)，當(dang)E(k)增(zeng)大(da)時，f[E(k)]減(jian)小(xiao)；反之則(ze)增(zeng)大(da)。每次采樣后，用f[E(k)]乘(cheng)E(k)，再進行累加。f[E(k)]與E(k)的(de)關系(xi)(xi)可表(biao)示為：

在該系統中，采用(yong)簡單的變(bian)速積(ji)分(fen)(fen)PI控制，取A=32，B=8，當誤差大于40時(shi)(shi)(shi)，系統相當于采用(yong)純比例調(diao)節(jie)，因(yin)此響應(ying)速度(du)加快；當誤差小于40并減(jian)小到8的過(guo)(guo)程中，積(ji)分(fen)(fen)作用(yong)開(kai)始并逐漸增強(qiang)，響應(ying)過(guo)(guo)程快速平(ping)滑；當誤差小于8時(shi)(shi)(shi)，完全引進(jin)積(ji)分(fen)(fen)作用(yong)，能快速有效(xiao)地消除靜差。該方法可有效(xiao)抑制系統的超(chao)調(diao)，同時(shi)(shi)(shi)也可兼顧(gu)系統的響應(ying)速度(du)。

4 實驗結果

利(li)用PI，IP和變(bian)速(su)(su)(su)積分(fen)PI數(shu)字電(dian)(dian)壓調(diao)(diao)(diao)(diao)節器的(de)(de)(de)逆(ni)變(bian)子(zi)系(xi)統(tong)對該設計(ji)方案(an)進(jin)行了大(da)(da)量(liang)實(shi)驗(yan)。結果可(ke)見(jian)，采(cai)用變(bian)速(su)(su)(su)積分(fen)PI數(shu)字電(dian)(dian)壓調(diao)(diao)(diao)(diao)節器的(de)(de)(de)綜合性(xing)(xing)能(neng)優于(yu)前兩(liang)種算(suan)(suan)法(fa)(fa)。圖6示(shi)出采(cai)用PI調(diao)(diao)(diao)(diao)節、IP調(diao)(diao)(diao)(diao)節，以及(ji)變(bian)速(su)(su)(su)積分(fen)PI調(diao)(diao)(diao)(diao)節時用100M-Tektronix TDS220存(cun)儲示(shi)波器獲取(qu)的(de)(de)(de)一組直流母線電(dian)(dian)壓Ud的(de)(de)(de)實(shi)驗(yan)對比波形。逆(ni)變(bian)器起動時Ud由150V升至(zhi)200V。由圖6可(ke)見(jian)。3種調(diao)(diao)(diao)(diao)節器在無(wu)靜差(cha)調(diao)(diao)(diao)(diao)節方面(mian)的(de)(de)(de)性(xing)(xing)能(neng)相同，而IP的(de)(de)(de)上升時間明(ming)(ming)顯大(da)(da)于(yu)另(ling)外兩(liang)種算(suan)(suan)法(fa)(fa)；在抑制超(chao)調(diao)(diao)(diao)(diao)及(ji)高頻噪聲誘發振蕩方面(mian)，變(bian)速(su)(su)(su)積分(fen)PI法(fa)(fa)有著明(ming)(ming)顯的(de)(de)(de)上風，PI系(xi)統(tong)的(de)(de)(de)起動超(chao)調(diao)(diao)(diao)(diao)超(chao)過20V，IP系(xi)統(tong)的(de)(de)(de)超(chao)調(diao)(diao)(diao)(diao)不到10V，而變(bian)速(su)(su)(su)積分(fen)PI系(xi)統(tong)則無(wu)超(chao)調(diao)(diao)(diao)(diao)。無(wu)振蕩，能(neng)很快進(jin)進(jin)穩定狀(zhuang)態：在抗干擾性(xing)(xing)能(neng)方面(mian)，變(bian)速(su)(su)(su)積分(fen)PI系(xi)統(tong)也(ye)具有同樣(yang)的(de)(de)(de)特(te)點(dian)。

5 結論

先容的(de)逆變器采(cai)用(yong)了直流母線(xian)電(dian)壓的(de)恒壓數(shu)字調(diao)節，可方便地(di)實(shi)現(xian)電(dian)網能量和蓄(xu)電(dian)池(chi)(chi)能量的(de)雙向活動，精密(mi)鎖(suo)相的(de)SPWM控(kong)(kong)(kong)制(zhi)(zhi)(zhi)可獲得接近于(yu)1的(de)功率因(yin)數(shu)，理論分(fen)析(xi)和系統實(shi)驗表明，在DSP控(kong)(kong)(kong)制(zhi)(zhi)(zhi)采(cai)樣周(zhou)期即是交流電(dian)源(yuan)周(zhou)期的(de)交流控(kong)(kong)(kong)制(zhi)(zhi)(zhi)系統中，采(cai)用(yong)變速積分(fen)PI調(diao)節更易(yi)獲得小超調(diao)、無振蕩、無靜差的(de)控(kong)(kong)(kong)制(zhi)(zhi)(zhi)性能指標。該設計系統可攜帶15路(lu)3A蓄(xu)電(dian)池(chi)(chi)組(zu)(每組(zu)12V蓄(xu)電(dian)池(chi)(chi)15節串聯)進行充放(fang)電(dian)子系統工作(zuo)，每路(lu)工作(zuo)由(you)工控(kong)(kong)(kong)機(ji)編(bian)程獨立控(kong)(kong)(kong)制(zhi)(zhi)(zhi)。通過對充電(dian)組(zu)和放(fang)電(dian)組(zu)的(de)公(gong)道配(pei)置(zhi)，可獲得明顯的(de)節能效(xiao)果(guo)。