基于DSP的蓄電池充(chong)放電裝置(zhi)原理

1 引言

在(zai)蓄電(dian)(dian)(dian)(dian)池生(sheng)產過程中，為(wei)(wei)了(le)保(bao)證產品(pin)質量，常(chang)需對(dui)成品(pin)蓄電(dian)(dian)(dian)(dian)池進行幾次(ci)充(chong)放(fang)電(dian)(dian)(dian)(dian)處理(li)。傳統(tong)充(chong)放(fang)電(dian)(dian)(dian)(dian)設備通常(chang)采用(yong)晶閘管作為(wei)(wei)整流逆(ni)變功(gong)率器件(jian)。裝(zhuang)置比較(jiao)(jiao)(jiao)復雜，交流輸進、輸出的(de)(de)(de)(de)功(gong)率因數較(jiao)(jiao)(jiao)低(di)。對(dui)電(dian)(dian)(dian)(dian)網的(de)(de)(de)(de)諧波污染(ran)也比較(jiao)(jiao)(jiao)大。為(wei)(wei)此，設計(ji)了(le)一(yi)種(zhong)三(san)相(xiang)SPWM整流逆(ni)變蓄電(dian)(dian)(dian)(dian)池充(chong)放(fang)電(dian)(dian)(dian)(dian)裝(zhuang)置。它采用(yong)IGBT作為(wei)(wei)功(gong)率變換(huan)器件(jian)。交流側以精密鎖(suo)相(xiang)的(de)(de)(de)(de)正(zheng)弦波電(dian)(dian)(dian)(dian)流實(shi)現(xian)電(dian)(dian)(dian)(dian)能(neng)變換(huan)。可獲接近(jin)于1的(de)(de)(de)(de)功(gong)率因數，實(shi)現(xian)對(dui)蓄電(dian)(dian)(dian)(dian)池的(de)(de)(de)(de)充(chong)放(fang)電(dian)(dian)(dian)(dian)處理(li)，明(ming)顯降(jiang)低(di)了(le)對(dui)電(dian)(dian)(dian)(dian)網的(de)(de)(de)(de)諧波污染(ran)，滿足了(le)綠色環保(bao)和節能(neng)的(de)(de)(de)(de)設計(ji)要求。

2 系統結構及工作原理

圖1示出設計的蓄(xu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)生產用充(chong)放電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)控(kong)制系(xi)統結構(gou)。該系(xi)統從原理上可劃(hua)分(fen)為SPWM雙向逆(ni)(ni)變和DC／DC變換(huan)(huan)充(chong)放電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)兩個(ge)子(zi)系(xi)統。前(qian)者，在蓄(xu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)充(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)時，通過三相(xiang)PFC升壓(ya)控(kong)制實(shi)(shi)現AC／DC變換(huan)(huan)。將交流(liu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)網(wang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)轉換(huan)(huan)成(cheng)蓄(xu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)充(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)所需的直(zhi)(zhi)(zhi)流(liu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)；在蓄(xu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)放電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)時，通過三相(xiang)PFC恒壓(ya)逆(ni)(ni)變控(kong)制實(shi)(shi)現DC／AC變換(huan)(huan)，將蓄(xu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)開釋(shi)的能(neng)(neng)量(liang)回饋電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)網(wang)。后者，完成(cheng)逆(ni)(ni)變直(zhi)(zhi)(zhi)流(liu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)能(neng)(neng)與蓄(xu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)能(neng)(neng)的轉換(huan)(huan)，以保證蓄(xu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)充(chong)放電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)過程中所要求(qiu)的電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)、電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)和時間的控(kong)制。各(ge)子(zi)系(xi)統采(cai)用單(dan)獨的DSP治理，DSP部(bu)分(fen)以模(mo)板化直(zhi)(zhi)(zhi)插(cha)結構(gou)直(zhi)(zhi)(zhi)接插(cha)進(jin)工(gong)控(kong)機(ji)的主板，工(gong)控(kong)機(ji)承擔整個(ge)系(xi)統的監(jian)控(kong)治理。系(xi)統由1個(ge)逆(ni)(ni)變子(zi)系(xi)統和n個(ge)(實(shi)(shi)驗樣(yang)機(ji)設計為15個(ge))充(chong)放電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)子(zi)系(xi)統組成(cheng)。系(xi)統工(gong)作(zuo)(zuo)時，可通過工(gong)控(kong)機(ji)編組，使(shi)后路蓄(xu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)工(gong)作(zuo)(zuo)于充(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)狀態；n-k路工(gong)作(zuo)(zuo)于放電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)狀態，這樣(yang)蓄(xu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)能(neng)(neng)量(liang)就可直(zhi)(zhi)(zhi)接在系(xi)統內部(bu)進(jin)行交換(huan)(huan)，從而明顯進(jin)步了節能(neng)(neng)效(xiao)果。圖2示出三相(xiang)SPWM雙向逆(ni)(ni)變電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路采(cai)用的典型電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)型結構(gou)主電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路。

三相反饋電(dian)(dian)流iuf，ivf，iwf用于跟蹤由DSP產生的(de)電(dian)(dian)流給定(ding)信(xin)號，從而控制直流端電(dian)(dian)壓(ya)Ud的(de)穩(wen)定(ding)；Ud的(de)反饋電(dian)(dian)壓(ya)Ut的(de)值經DSP采樣后通過電(dian)(dian)壓(ya)調節得到(dao)作用于電(dian)(dian)流內環(huan)的(de)電(dian)(dian)流給定(ding)值。

圖(tu)(tu)3示出單(dan)相PWM整(zheng)流(liu)電路的(de)相量圖(tu)(tu)[2]。固然該系統(tong)采用(yong)的(de)是(shi)(shi)三相PWM整(zheng)流(liu)電路．但其(qi)工作(zuo)原(yuan)理與單(dan)相電路相似，只是(shi)(shi)從單(dan)相擴展到(dao)三相。對電路進行(xing)SPWM控(kong)制(zhi)，在(zai)橋(qiao)的(de)交流(liu)輸進端A，B，C可得到(dao)三相橋(qiao)臂的(de)SPWM電壓(ya)uiu，uiv，uiw。對其(qi)各(ge)(ge)相按圖(tu)(tu)3的(de)相量圖(tu)(tu)進行(xing)控(kong)制(zhi)，就可使各(ge)(ge)相電流(liu)iu，iv，iw為(wei)正弦波。且與電壓(ya)同相位，功率因(yin)數近似為(wei)1。

由(you)此可知，控制uiu的(de)大小和(he)相位δ即可控制電流(liu)的(de)大小和(he)流(liu)向(xiang)(xiang)，從而控制功率的(de)大小和(he)方向(xiang)(xiang)。通過對(dui)Ud的(de)恒壓控制，實(shi)現(xian)逆變器的(de)功率流(liu)向(xiang)(xiang)，從而實(shi)現(xian)能(neng)量的(de)自動(dong)雙(shuang)向(xiang)(xiang)活動(dong)。

3 電壓控制器的設計

圖(tu)4示出(chu)AD／DC逆(ni)變控(kong)(kong)制框圖(tu)。該(gai)系(xi)統采(cai)用(yong)電(dian)(dian)(dian)壓(ya)(ya)、電(dian)(dian)(dian)流(liu)(liu)(liu)雙(shuang)閉環(huan)控(kong)(kong)制結構，其電(dian)(dian)(dian)壓(ya)(ya)控(kong)(kong)制對(dui)象(xiang)為(wei)直流(liu)(liu)(liu)量(liang)；電(dian)(dian)(dian)流(liu)(liu)(liu)控(kong)(kong)制對(dui)象(xiang)為(wei)交流(liu)(liu)(liu)量(liang)。電(dian)(dian)(dian)壓(ya)(ya)外環(huan)采(cai)用(yong)數(shu)字算(suan)法予以(yi)實(shi)現(xian)；電(dian)(dian)(dian)流(liu)(liu)(liu)內環(huan)采(cai)用(yong)模擬電(dian)(dian)(dian)路予以(yi)實(shi)現(xian)，以(yi)確保(bao)快(kuai)速(su)進(jin)行電(dian)(dian)(dian)流(liu)(liu)(liu)控(kong)(kong)制，進(jin)步系(xi)統工(gong)作的可靠性。同(tong)時(shi)，為(wei)了使誤(wu)差電(dian)(dian)(dian)流(liu)(liu)(liu)與給定相位(wei)保(bao)持一致(zhi)。電(dian)(dian)(dian)流(liu)(liu)(liu)調節器采(cai)用(yong)比例控(kong)(kong)制。

蓄(xu)(xu)電(dian)(dian)(dian)(dian)池充(chong)電(dian)(dian)(dian)(dian)時(shi)(shi)，輸出電(dian)(dian)(dian)(dian)壓Ud低于給(gei)定(ding)(ding)值(zhi)Ud*，則(ze)電(dian)(dian)(dian)(dian)壓調節器(qi)輸出正(zheng)的(de)uc，輸進電(dian)(dian)(dian)(dian)壓Uin經過一個比例因子Ku后得到一個與(yu)Uin同相(xiang)的(de)單(dan)位(wei)(wei)正(zheng)弦us，uc與(yu)us的(de)乘積作(zuo)(zuo)為給(gei)定(ding)(ding)電(dian)(dian)(dian)(dian)流(liu)(liu)i*，與(yu)Uin同相(xiang)，控制(zhi)i跟隨(sui)i*，則(ze)能(neng)(neng)量(liang)(liang)就以(yi)單(dan)位(wei)(wei)功(gong)(gong)率(lv)因數(shu)從電(dian)(dian)(dian)(dian)網流(liu)(liu)向(xiang)蓄(xu)(xu)電(dian)(dian)(dian)(dian)池。此時(shi)(shi)，變流(liu)(liu)器(qi)工作(zuo)(zuo)在整流(liu)(liu)狀(zhuang)態(tai)。蓄(xu)(xu)電(dian)(dian)(dian)(dian)池放電(dian)(dian)(dian)(dian)時(shi)(shi)，Ud高于Ud*，則(ze)uc為負值(zhi)，uc與(yu)us相(xiang)乘得到與(yu)Uin反向(xiang)的(de)給(gei)定(ding)(ding)電(dian)(dian)(dian)(dian)流(liu)(liu)i*，控制(zhi)i跟隨(sui)i*，能(neng)(neng)量(liang)(liang)就能(neng)(neng)以(yi)單(dan)位(wei)(wei)功(gong)(gong)率(lv)因數(shu)從蓄(xu)(xu)電(dian)(dian)(dian)(dian)池流(liu)(liu)向(xiang)電(dian)(dian)(dian)(dian)網。此時(shi)(shi)，變流(liu)(liu)器(qi)工作(zuo)(zuo)在逆(ni)變狀(zhuang)態(tai)。電(dian)(dian)(dian)(dian)壓外環產生(sheng)輸進給(gei)定(ding)(ding)電(dian)(dian)(dian)(dian)流(liu)(liu)i*，其幅值(zhi)表明了(le)功(gong)(gong)率(lv)的(de)大小；符號決定(ding)(ding)了(le)功(gong)(gong)率(lv)的(de)流(liu)(liu)向(xiang)；相(xiang)位(wei)(wei)決定(ding)(ding)了(le)能(neng)(neng)量(liang)(liang)傳遞的(de)功(gong)(gong)率(lv)因數(shu)。電(dian)(dian)(dian)(dian)流(liu)(liu)內環使輸進電(dian)(dian)(dian)(dian)流(liu)(liu)跟蹤(zong)給(gei)定(ding)(ding)，從而實現(xian)可逆(ni)的(de)單(dan)位(wei)(wei)功(gong)(gong)率(lv)因數(shu)變換。

系統采用TMS320LF2407A DSP作為主處理(li)器，因其(qi)有豐富的(de)(de)外設和較(jiao)高的(de)(de)運(yun)算速(su)度。由此可(ke)實現較(jiao)復雜的(de)(de)控(kong)(kong)制及高精(jing)度的(de)(de)數據處理(li)。在此，通過對(dui)PI控(kong)(kong)制、IP控(kong)(kong)制和變速(su)積分PI控(kong)(kong)制三種電壓(ya)調節器算法的(de)(de)實驗(yan)得出其(qi)優劣，從而選擇最適合該系統的(de)(de)控(kong)(kong)制算法進行電壓(ya)調節。

(1)PI控制算法和IP控制算法

圖5a示出(chu)PI調節(jie)器(qi)結構(gou)圖。由圖可(ke)得其傳遞

比(bi)較式(5)和式(6)可(ke)見(jian)，兩(liang)種系(xi)統的傳遞函數(shu)分母相同(tong)(tong)(tong)，故IP調節(jie)(jie)器可(ke)持有(you)與PI相同(tong)(tong)(tong)的無靜差調節(jie)(jie)和穩(wen)定(ding)(ding)(ding)特性，同(tong)(tong)(tong)時因(yin)(yin)它在傳遞函數(shu)上比(bi)PI少一個零點，因(yin)(yin)此(ci)具(ju)有(you)比(bi)PI更好的高頻衰(shuai)減(jian)特性，輕(qing)易滿足較長(chang)采樣周期(qi)數(shu)字調節(jie)(jie)的穩(wen)定(ding)(ding)(ding)性要求，能有(you)效抑(yi)制(zhi)混迭現象(xiang)。系(xi)統實(shi)驗證實(shi)，采用IP調節(jie)(jie)，調節(jie)(jie)器參數(shu)很輕(qing)易整(zheng)定(ding)(ding)(ding)。可(ke)使系(xi)統達(da)到(dao)穩(wen)定(ding)(ding)(ding)、無靜差和很小的超調。不過在快速性方面將有(you)損失。

(2)變速積分PI控制算法

在傳(chuan)統的(de)(de)PI算法中(zhong)，因積(ji)(ji)分(fen)(fen)(fen)增(zeng)益Ki為(wei)(wei)常數(shu)，在整個調節過(guo)程中(zhong)，其(qi)值不變。但系(xi)統對積(ji)(ji)分(fen)(fen)(fen)的(de)(de)要(yao)求(qiu)是(shi)偏(pian)差(cha)(cha)大時(shi)，積(ji)(ji)分(fen)(fen)(fen)作用(yong)(yong)減(jian)弱，否則會產生超(chao)調，甚至出現積(ji)(ji)分(fen)(fen)(fen)飽和(he)；反(fan)之則加強(qiang)，否則不能滿足正確性的(de)(de)要(yao)求(qiu)。引進變速(su)(su)積(ji)(ji)分(fen)(fen)(fen)PI控制(zhi)算法能使控制(zhi)性能得以(yi)滿足。其(qi)基本(ben)思路是(shi)偏(pian)差(cha)(cha)大時(shi)，積(ji)(ji)分(fen)(fen)(fen)累(lei)積(ji)(ji)速(su)(su)度慢，積(ji)(ji)分(fen)(fen)(fen)作用(yong)(yong)弱；偏(pian)差(cha)(cha)小時(shi)，積(ji)(ji)分(fen)(fen)(fen)累(lei)積(ji)(ji)速(su)(su)度快，積(ji)(ji)分(fen)(fen)(fen)作用(yong)(yong)強(qiang)。為(wei)(wei)此(ci)，設置(zhi)系(xi)數(shu)f[E(k)]，它是(shi)偏(pian)差(cha)(cha)E(k)的(de)(de)函數(shu)，當E(k)增(zeng)大時(shi)，f[E(k)]減(jian)小；反(fan)之則增(zeng)大。每次采樣(yang)后，用(yong)(yong)f[E(k)]乘(cheng)E(k)，再進行累(lei)加。f[E(k)]與E(k)的(de)(de)關系(xi)可表示為(wei)(wei)：

在該系(xi)統(tong)(tong)中，采用簡單的(de)變速(su)積分PI控制，取A=32，B=8，當(dang)誤(wu)差(cha)大于(yu)40時，系(xi)統(tong)(tong)相(xiang)當(dang)于(yu)采用純比(bi)例調節，因此響應(ying)速(su)度(du)加快(kuai)(kuai)；當(dang)誤(wu)差(cha)小于(yu)40并減小到8的(de)過(guo)程中，積分作(zuo)用開始并逐漸增強，響應(ying)過(guo)程快(kuai)(kuai)速(su)平滑(hua)；當(dang)誤(wu)差(cha)小于(yu)8時，完(wan)全引進(jin)積分作(zuo)用，能快(kuai)(kuai)速(su)有(you)效(xiao)地消除(chu)靜差(cha)。該方(fang)法可(ke)有(you)效(xiao)抑制系(xi)統(tong)(tong)的(de)超調，同時也可(ke)兼顧系(xi)統(tong)(tong)的(de)響應(ying)速(su)度(du)。

4 實驗結果

利用(yong)(yong)PI，IP和變(bian)(bian)速(su)積分(fen)(fen)PI數(shu)字電(dian)壓(ya)調(diao)(diao)(diao)節(jie)(jie)(jie)器(qi)的(de)(de)逆變(bian)(bian)子系(xi)(xi)(xi)統(tong)對該設計(ji)方(fang)案進行了大(da)量實(shi)驗(yan)。結(jie)果可見，采(cai)用(yong)(yong)變(bian)(bian)速(su)積分(fen)(fen)PI數(shu)字電(dian)壓(ya)調(diao)(diao)(diao)節(jie)(jie)(jie)器(qi)的(de)(de)綜合性能優于(yu)前(qian)兩種(zhong)(zhong)算法。圖6示(shi)出采(cai)用(yong)(yong)PI調(diao)(diao)(diao)節(jie)(jie)(jie)、IP調(diao)(diao)(diao)節(jie)(jie)(jie)，以及變(bian)(bian)速(su)積分(fen)(fen)PI調(diao)(diao)(diao)節(jie)(jie)(jie)時用(yong)(yong)100M-Tektronix TDS220存儲示(shi)波器(qi)獲(huo)取(qu)的(de)(de)一組直流母線電(dian)壓(ya)Ud的(de)(de)實(shi)驗(yan)對比波形(xing)。逆變(bian)(bian)器(qi)起動(dong)時Ud由150V升至200V。由圖6可見。3種(zhong)(zhong)調(diao)(diao)(diao)節(jie)(jie)(jie)器(qi)在無(wu)(wu)靜差調(diao)(diao)(diao)節(jie)(jie)(jie)方(fang)面的(de)(de)性能相同，而(er)IP的(de)(de)上(shang)(shang)升時間明顯大(da)于(yu)另(ling)外兩種(zhong)(zhong)算法；在抑制超(chao)調(diao)(diao)(diao)及高頻噪聲誘發振蕩(dang)(dang)方(fang)面，變(bian)(bian)速(su)積分(fen)(fen)PI法有著明顯的(de)(de)上(shang)(shang)風，PI系(xi)(xi)(xi)統(tong)的(de)(de)起動(dong)超(chao)調(diao)(diao)(diao)超(chao)過20V，IP系(xi)(xi)(xi)統(tong)的(de)(de)超(chao)調(diao)(diao)(diao)不到10V，而(er)變(bian)(bian)速(su)積分(fen)(fen)PI系(xi)(xi)(xi)統(tong)則(ze)無(wu)(wu)超(chao)調(diao)(diao)(diao)。無(wu)(wu)振蕩(dang)(dang)，能很快進進穩定狀(zhuang)態：在抗干擾(rao)性能方(fang)面，變(bian)(bian)速(su)積分(fen)(fen)PI系(xi)(xi)(xi)統(tong)也具有同樣的(de)(de)特點。

5 結論

先容的逆變(bian)器(qi)采用(yong)了直(zhi)流(liu)母線電壓的恒壓數字調節(jie)，可(ke)方便地(di)實現(xian)電網(wang)能(neng)量(liang)和(he)蓄電池(chi)能(neng)量(liang)的雙向活(huo)動，精密鎖相的SPWM控(kong)(kong)制(zhi)可(ke)獲得接近于1的功率因數，理論分(fen)析(xi)和(he)系統實驗表明，在DSP控(kong)(kong)制(zhi)采樣(yang)周(zhou)期即是交流(liu)電源周(zhou)期的交流(liu)控(kong)(kong)制(zhi)系統中，采用(yong)變(bian)速(su)積分(fen)PI調節(jie)更易獲得小超調、無振蕩、無靜差的控(kong)(kong)制(zhi)性能(neng)指標(biao)。該(gai)設計(ji)系統可(ke)攜帶(dai)15路3A蓄電池(chi)組(zu)(每組(zu)12V蓄電池(chi)15節(jie)串聯(lian))進行(xing)充放電子系統工作(zuo)，每路工作(zuo)由工控(kong)(kong)機(ji)編程獨立控(kong)(kong)制(zhi)。通過對(dui)充電組(zu)和(he)放電組(zu)的公道配置，可(ke)獲得明顯(xian)的節(jie)能(neng)效(xiao)果。