基于DSP的蓄電池充放電裝置(zhi)原理

1 引言

在蓄(xu)電(dian)池(chi)生產過(guo)程中，為(wei)了保證產品質量，常需對(dui)成品蓄(xu)電(dian)池(chi)進(jin)行幾次充放電(dian)處理。傳統充放電(dian)設備通常采用晶閘管作為(wei)整流逆變功率(lv)器件(jian)。裝置比較(jiao)(jiao)復(fu)雜(za)，交流輸(shu)進(jin)、輸(shu)出的(de)(de)功率(lv)因數較(jiao)(jiao)低。對(dui)電(dian)網的(de)(de)諧波(bo)污(wu)(wu)染(ran)(ran)也(ye)比較(jiao)(jiao)大。為(wei)此，設計了一種(zhong)三相(xiang)SPWM整流逆變蓄(xu)電(dian)池(chi)充放電(dian)裝置。它(ta)采用IGBT作為(wei)功率(lv)變換器件(jian)。交流側(ce)以精(jing)密(mi)鎖相(xiang)的(de)(de)正弦(xian)波(bo)電(dian)流實現(xian)電(dian)能變換。可獲接(jie)近(jin)于(yu)1的(de)(de)功率(lv)因數，實現(xian)對(dui)蓄(xu)電(dian)池(chi)的(de)(de)充放電(dian)處理，明顯降低了對(dui)電(dian)網的(de)(de)諧波(bo)污(wu)(wu)染(ran)(ran)，滿(man)足了綠色環保和(he)節(jie)能的(de)(de)設計要求(qiu)。

2 系統結構及工作原理

圖1示(shi)出設(she)計(ji)的(de)(de)(de)(de)蓄(xu)(xu)電(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)生(sheng)產用(yong)(yong)(yong)充(chong)放(fang)電(dian)(dian)(dian)(dian)(dian)控(kong)(kong)(kong)制系(xi)(xi)統(tong)(tong)(tong)(tong)結(jie)構。該系(xi)(xi)統(tong)(tong)(tong)(tong)從原(yuan)理上可(ke)(ke)(ke)劃分為SPWM雙向逆(ni)變(bian)(bian)和(he)DC／DC變(bian)(bian)換(huan)充(chong)放(fang)電(dian)(dian)(dian)(dian)(dian)兩個(ge)(ge)(ge)子(zi)系(xi)(xi)統(tong)(tong)(tong)(tong)。前者，在蓄(xu)(xu)電(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)充(chong)電(dian)(dian)(dian)(dian)(dian)時，通(tong)過(guo)三(san)相(xiang)PFC升壓(ya)控(kong)(kong)(kong)制實(shi)現AC／DC變(bian)(bian)換(huan)。將(jiang)交流(liu)(liu)(liu)電(dian)(dian)(dian)(dian)(dian)網(wang)電(dian)(dian)(dian)(dian)(dian)壓(ya)轉(zhuan)換(huan)成蓄(xu)(xu)電(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)充(chong)電(dian)(dian)(dian)(dian)(dian)所(suo)需(xu)的(de)(de)(de)(de)直(zhi)流(liu)(liu)(liu)電(dian)(dian)(dian)(dian)(dian)壓(ya)；在蓄(xu)(xu)電(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)放(fang)電(dian)(dian)(dian)(dian)(dian)時，通(tong)過(guo)三(san)相(xiang)PFC恒壓(ya)逆(ni)變(bian)(bian)控(kong)(kong)(kong)制實(shi)現DC／AC變(bian)(bian)換(huan)，將(jiang)蓄(xu)(xu)電(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)開釋的(de)(de)(de)(de)能(neng)(neng)量回饋電(dian)(dian)(dian)(dian)(dian)網(wang)。后(hou)者，完成逆(ni)變(bian)(bian)直(zhi)流(liu)(liu)(liu)電(dian)(dian)(dian)(dian)(dian)能(neng)(neng)與蓄(xu)(xu)電(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)電(dian)(dian)(dian)(dian)(dian)能(neng)(neng)的(de)(de)(de)(de)轉(zhuan)換(huan)，以(yi)(yi)保證蓄(xu)(xu)電(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)充(chong)放(fang)電(dian)(dian)(dian)(dian)(dian)過(guo)程中所(suo)要求的(de)(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)、電(dian)(dian)(dian)(dian)(dian)壓(ya)和(he)時間的(de)(de)(de)(de)控(kong)(kong)(kong)制。各(ge)子(zi)系(xi)(xi)統(tong)(tong)(tong)(tong)采用(yong)(yong)(yong)單獨的(de)(de)(de)(de)DSP治(zhi)理，DSP部(bu)分以(yi)(yi)模板化直(zhi)插結(jie)構直(zhi)接(jie)插進工(gong)(gong)(gong)控(kong)(kong)(kong)機的(de)(de)(de)(de)主板，工(gong)(gong)(gong)控(kong)(kong)(kong)機承擔(dan)整個(ge)(ge)(ge)系(xi)(xi)統(tong)(tong)(tong)(tong)的(de)(de)(de)(de)監控(kong)(kong)(kong)治(zhi)理。系(xi)(xi)統(tong)(tong)(tong)(tong)由1個(ge)(ge)(ge)逆(ni)變(bian)(bian)子(zi)系(xi)(xi)統(tong)(tong)(tong)(tong)和(he)n個(ge)(ge)(ge)(實(shi)驗(yan)樣機設(she)計(ji)為15個(ge)(ge)(ge))充(chong)放(fang)電(dian)(dian)(dian)(dian)(dian)子(zi)系(xi)(xi)統(tong)(tong)(tong)(tong)組成。系(xi)(xi)統(tong)(tong)(tong)(tong)工(gong)(gong)(gong)作時，可(ke)(ke)(ke)通(tong)過(guo)工(gong)(gong)(gong)控(kong)(kong)(kong)機編組，使后(hou)路蓄(xu)(xu)電(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)工(gong)(gong)(gong)作于(yu)充(chong)電(dian)(dian)(dian)(dian)(dian)狀態(tai)；n-k路工(gong)(gong)(gong)作于(yu)放(fang)電(dian)(dian)(dian)(dian)(dian)狀態(tai)，這樣蓄(xu)(xu)電(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)(chi)能(neng)(neng)量就可(ke)(ke)(ke)直(zhi)接(jie)在系(xi)(xi)統(tong)(tong)(tong)(tong)內部(bu)進行交換(huan)，從而明顯進步了節能(neng)(neng)效(xiao)果。圖2示(shi)出三(san)相(xiang)SPWM雙向逆(ni)變(bian)(bian)電(dian)(dian)(dian)(dian)(dian)路采用(yong)(yong)(yong)的(de)(de)(de)(de)典型電(dian)(dian)(dian)(dian)(dian)壓(ya)型結(jie)構主電(dian)(dian)(dian)(dian)(dian)路。

三(san)相反饋電(dian)(dian)流(liu)iuf，ivf，iwf用(yong)于跟蹤由(you)DSP產生的電(dian)(dian)流(liu)給定信號，從(cong)而控制直流(liu)端電(dian)(dian)壓(ya)Ud的穩定；Ud的反饋電(dian)(dian)壓(ya)Ut的值(zhi)經DSP采樣后通過電(dian)(dian)壓(ya)調節(jie)得到作用(yong)于電(dian)(dian)流(liu)內環的電(dian)(dian)流(liu)給定值(zhi)。

圖(tu)3示出單相(xiang)(xiang)(xiang)PWM整(zheng)流電(dian)(dian)路(lu)的(de)相(xiang)(xiang)(xiang)量(liang)圖(tu)[2]。固然該系統采用的(de)是三相(xiang)(xiang)(xiang)PWM整(zheng)流電(dian)(dian)路(lu)．但其工作原理與單相(xiang)(xiang)(xiang)電(dian)(dian)路(lu)相(xiang)(xiang)(xiang)似(si)(si)，只是從單相(xiang)(xiang)(xiang)擴展到三相(xiang)(xiang)(xiang)。對電(dian)(dian)路(lu)進(jin)(jin)(jin)行SPWM控(kong)制，在橋的(de)交流輸進(jin)(jin)(jin)端A，B，C可(ke)得到三相(xiang)(xiang)(xiang)橋臂的(de)SPWM電(dian)(dian)壓uiu，uiv，uiw。對其各相(xiang)(xiang)(xiang)按(an)圖(tu)3的(de)相(xiang)(xiang)(xiang)量(liang)圖(tu)進(jin)(jin)(jin)行控(kong)制，就可(ke)使各相(xiang)(xiang)(xiang)電(dian)(dian)流iu，iv，iw為正弦波。且與電(dian)(dian)壓同相(xiang)(xiang)(xiang)位，功(gong)率因數近(jin)似(si)(si)為1。

由此(ci)可知，控制uiu的(de)大(da)小和(he)相位δ即可控制電流(liu)(liu)的(de)大(da)小和(he)流(liu)(liu)向(xiang)，從而控制功率的(de)大(da)小和(he)方向(xiang)。通過對Ud的(de)恒壓(ya)控制，實現逆變器的(de)功率流(liu)(liu)向(xiang)，從而實現能量的(de)自動雙向(xiang)活動。

3 電壓控制器的設計

圖(tu)4示出(chu)AD／DC逆變控(kong)制(zhi)框圖(tu)。該系統采用(yong)電(dian)(dian)(dian)壓(ya)、電(dian)(dian)(dian)流(liu)(liu)雙(shuang)閉環控(kong)制(zhi)結構，其電(dian)(dian)(dian)壓(ya)控(kong)制(zhi)對象為(wei)(wei)直流(liu)(liu)量(liang)；電(dian)(dian)(dian)流(liu)(liu)控(kong)制(zhi)對象為(wei)(wei)交流(liu)(liu)量(liang)。電(dian)(dian)(dian)壓(ya)外環采用(yong)數(shu)字算法予以(yi)(yi)實現；電(dian)(dian)(dian)流(liu)(liu)內環采用(yong)模(mo)擬電(dian)(dian)(dian)路予以(yi)(yi)實現，以(yi)(yi)確保(bao)快(kuai)速進行電(dian)(dian)(dian)流(liu)(liu)控(kong)制(zhi)，進步系統工作的可靠(kao)性。同(tong)時，為(wei)(wei)了(le)使誤差電(dian)(dian)(dian)流(liu)(liu)與給定相位(wei)保(bao)持一致。電(dian)(dian)(dian)流(liu)(liu)調節器采用(yong)比例控(kong)制(zhi)。

蓄(xu)(xu)電(dian)(dian)(dian)池(chi)(chi)(chi)充電(dian)(dian)(dian)時(shi)，輸(shu)出電(dian)(dian)(dian)壓(ya)Ud低(di)于給定(ding)(ding)值(zhi)Ud*，則電(dian)(dian)(dian)壓(ya)調節器輸(shu)出正的(de)(de)(de)uc，輸(shu)進(jin)電(dian)(dian)(dian)壓(ya)Uin經過一個比例因(yin)子Ku后得(de)到一個與(yu)Uin同相(xiang)的(de)(de)(de)單(dan)位正弦us，uc與(yu)us的(de)(de)(de)乘積作(zuo)為給定(ding)(ding)電(dian)(dian)(dian)流(liu)(liu)(liu)i*，與(yu)Uin同相(xiang)，控制(zhi)i跟隨(sui)i*，則能(neng)量(liang)就以單(dan)位功(gong)率(lv)因(yin)數(shu)從(cong)電(dian)(dian)(dian)網流(liu)(liu)(liu)向(xiang)蓄(xu)(xu)電(dian)(dian)(dian)池(chi)(chi)(chi)。此時(shi)，變流(liu)(liu)(liu)器工作(zuo)在整流(liu)(liu)(liu)狀(zhuang)態(tai)。蓄(xu)(xu)電(dian)(dian)(dian)池(chi)(chi)(chi)放電(dian)(dian)(dian)時(shi)，Ud高于Ud*，則uc為負值(zhi)，uc與(yu)us相(xiang)乘得(de)到與(yu)Uin反向(xiang)的(de)(de)(de)給定(ding)(ding)電(dian)(dian)(dian)流(liu)(liu)(liu)i*，控制(zhi)i跟隨(sui)i*，能(neng)量(liang)就能(neng)以單(dan)位功(gong)率(lv)因(yin)數(shu)從(cong)蓄(xu)(xu)電(dian)(dian)(dian)池(chi)(chi)(chi)流(liu)(liu)(liu)向(xiang)電(dian)(dian)(dian)網。此時(shi)，變流(liu)(liu)(liu)器工作(zuo)在逆(ni)變狀(zhuang)態(tai)。電(dian)(dian)(dian)壓(ya)外環(huan)產生輸(shu)進(jin)給定(ding)(ding)電(dian)(dian)(dian)流(liu)(liu)(liu)i*，其幅值(zhi)表明了功(gong)率(lv)的(de)(de)(de)大小；符(fu)號決定(ding)(ding)了功(gong)率(lv)的(de)(de)(de)流(liu)(liu)(liu)向(xiang)；相(xiang)位決定(ding)(ding)了能(neng)量(liang)傳遞(di)的(de)(de)(de)功(gong)率(lv)因(yin)數(shu)。電(dian)(dian)(dian)流(liu)(liu)(liu)內環(huan)使輸(shu)進(jin)電(dian)(dian)(dian)流(liu)(liu)(liu)跟蹤給定(ding)(ding)，從(cong)而實現可逆(ni)的(de)(de)(de)單(dan)位功(gong)率(lv)因(yin)數(shu)變換(huan)。

系(xi)統采用TMS320LF2407A DSP作為(wei)主(zhu)處(chu)理器，因其有豐(feng)富的(de)(de)外設(she)和較高的(de)(de)運(yun)算(suan)(suan)速度(du)。由此可實現較復雜的(de)(de)控(kong)(kong)制(zhi)及(ji)高精(jing)度(du)的(de)(de)數據處(chu)理。在此，通過對PI控(kong)(kong)制(zhi)、IP控(kong)(kong)制(zhi)和變速積(ji)分(fen)PI控(kong)(kong)制(zhi)三種(zhong)電(dian)壓調節器算(suan)(suan)法(fa)的(de)(de)實驗得出其優劣，從(cong)而選擇最(zui)適合該系(xi)統的(de)(de)控(kong)(kong)制(zhi)算(suan)(suan)法(fa)進行電(dian)壓調節。

(1)PI控制算法和IP控制算法

圖(tu)5a示出PI調節器(qi)結(jie)構圖(tu)。由圖(tu)可得其傳遞

比較式(5)和式(6)可見，兩(liang)種系統(tong)的傳遞(di)函(han)數(shu)分母(mu)相同，故IP調節(jie)器可持有(you)與(yu)PI相同的無(wu)(wu)靜(jing)差(cha)調節(jie)和穩(wen)定特性(xing)，同時因它在傳遞(di)函(han)數(shu)上比PI少一個(ge)零點，因此具有(you)比PI更好的高頻(pin)衰減(jian)特性(xing)，輕易滿足(zu)較長采樣周(zhou)期數(shu)字(zi)調節(jie)的穩(wen)定性(xing)要求，能有(you)效(xiao)抑制(zhi)混迭(die)現象(xiang)。系統(tong)實驗(yan)證實，采用IP調節(jie)，調節(jie)器參數(shu)很(hen)輕易整定。可使系統(tong)達(da)到穩(wen)定、無(wu)(wu)靜(jing)差(cha)和很(hen)小的超調。不過在快(kuai)速性(xing)方面(mian)將有(you)損失。

(2)變速積分PI控制算法

在(zai)傳統(tong)的(de)(de)(de)PI算法中，因積(ji)(ji)(ji)(ji)(ji)分(fen)(fen)增(zeng)益Ki為常數(shu)(shu)，在(zai)整個調節過程中，其(qi)值不變。但系(xi)統(tong)對積(ji)(ji)(ji)(ji)(ji)分(fen)(fen)的(de)(de)(de)要(yao)求是偏(pian)差(cha)大(da)時(shi)(shi)，積(ji)(ji)(ji)(ji)(ji)分(fen)(fen)作用(yong)減(jian)弱，否(fou)則(ze)會產生超調，甚至出現積(ji)(ji)(ji)(ji)(ji)分(fen)(fen)飽(bao)和；反之則(ze)加(jia)強，否(fou)則(ze)不能(neng)滿(man)(man)足正(zheng)確性的(de)(de)(de)要(yao)求。引進變速(su)積(ji)(ji)(ji)(ji)(ji)分(fen)(fen)PI控(kong)制(zhi)算法能(neng)使控(kong)制(zhi)性能(neng)得以滿(man)(man)足。其(qi)基本思路是偏(pian)差(cha)大(da)時(shi)(shi)，積(ji)(ji)(ji)(ji)(ji)分(fen)(fen)累(lei)(lei)積(ji)(ji)(ji)(ji)(ji)速(su)度(du)慢，積(ji)(ji)(ji)(ji)(ji)分(fen)(fen)作用(yong)弱；偏(pian)差(cha)小時(shi)(shi)，積(ji)(ji)(ji)(ji)(ji)分(fen)(fen)累(lei)(lei)積(ji)(ji)(ji)(ji)(ji)速(su)度(du)快，積(ji)(ji)(ji)(ji)(ji)分(fen)(fen)作用(yong)強。為此，設置系(xi)數(shu)(shu)f[E(k)]，它是偏(pian)差(cha)E(k)的(de)(de)(de)函數(shu)(shu)，當(dang)E(k)增(zeng)大(da)時(shi)(shi)，f[E(k)]減(jian)小；反之則(ze)增(zeng)大(da)。每次(ci)采樣后(hou)，用(yong)f[E(k)]乘E(k)，再進行累(lei)(lei)加(jia)。f[E(k)]與E(k)的(de)(de)(de)關系(xi)可表(biao)示(shi)為：

在該系(xi)(xi)統(tong)中(zhong)，采用(yong)簡單的(de)變(bian)速(su)積(ji)分(fen)PI控制(zhi)，取(qu)A=32，B=8，當(dang)(dang)(dang)誤(wu)差大于(yu)40時，系(xi)(xi)統(tong)相當(dang)(dang)(dang)于(yu)采用(yong)純比例調(diao)節，因此響應(ying)速(su)度加快；當(dang)(dang)(dang)誤(wu)差小于(yu)40并(bing)減小到8的(de)過程中(zhong)，積(ji)分(fen)作(zuo)用(yong)開(kai)始并(bing)逐漸增強，響應(ying)過程快速(su)平(ping)滑；當(dang)(dang)(dang)誤(wu)差小于(yu)8時，完全引進積(ji)分(fen)作(zuo)用(yong)，能快速(su)有效(xiao)地消除(chu)靜差。該方法可有效(xiao)抑(yi)制(zhi)系(xi)(xi)統(tong)的(de)超調(diao)，同時也可兼(jian)顧系(xi)(xi)統(tong)的(de)響應(ying)速(su)度。

4 實驗結果

利用PI，IP和變(bian)(bian)速積分PI數字電壓調(diao)(diao)(diao)節(jie)器(qi)(qi)的(de)(de)逆(ni)(ni)變(bian)(bian)子系(xi)(xi)統對該設(she)計方(fang)(fang)(fang)案進行了大量實(shi)驗(yan)。結果可見，采用變(bian)(bian)速積分PI數字電壓調(diao)(diao)(diao)節(jie)器(qi)(qi)的(de)(de)綜合性能優于前(qian)兩(liang)種(zhong)算(suan)法。圖6示出(chu)采用PI調(diao)(diao)(diao)節(jie)、IP調(diao)(diao)(diao)節(jie)，以及(ji)變(bian)(bian)速積分PI調(diao)(diao)(diao)節(jie)時(shi)用100M-Tektronix TDS220存儲(chu)示波器(qi)(qi)獲取(qu)的(de)(de)一組直(zhi)流母線(xian)電壓Ud的(de)(de)實(shi)驗(yan)對比波形。逆(ni)(ni)變(bian)(bian)器(qi)(qi)起動時(shi)Ud由150V升至200V。由圖6可見。3種(zhong)調(diao)(diao)(diao)節(jie)器(qi)(qi)在無靜差調(diao)(diao)(diao)節(jie)方(fang)(fang)(fang)面(mian)的(de)(de)性能相同，而IP的(de)(de)上升時(shi)間明顯(xian)大于另外兩(liang)種(zhong)算(suan)法；在抑制超(chao)(chao)調(diao)(diao)(diao)及(ji)高頻噪聲誘發振蕩方(fang)(fang)(fang)面(mian)，變(bian)(bian)速積分PI法有著明顯(xian)的(de)(de)上風，PI系(xi)(xi)統的(de)(de)起動超(chao)(chao)調(diao)(diao)(diao)超(chao)(chao)過20V，IP系(xi)(xi)統的(de)(de)超(chao)(chao)調(diao)(diao)(diao)不(bu)到10V，而變(bian)(bian)速積分PI系(xi)(xi)統則無超(chao)(chao)調(diao)(diao)(diao)。無振蕩，能很快進進穩定狀態：在抗(kang)干擾性能方(fang)(fang)(fang)面(mian)，變(bian)(bian)速積分PI系(xi)(xi)統也(ye)具有同樣的(de)(de)特點。

5 結論

先(xian)容的逆變器采(cai)(cai)用(yong)了直流(liu)(liu)母線電(dian)(dian)(dian)壓的恒壓數(shu)字(zi)調(diao)節，可方便地實現電(dian)(dian)(dian)網能(neng)量和(he)蓄(xu)(xu)電(dian)(dian)(dian)池能(neng)量的雙向活動，精密鎖相(xiang)的SPWM控(kong)(kong)制(zhi)可獲得接近于1的功率因(yin)數(shu)，理論(lun)分析和(he)系統(tong)實驗表明(ming)，在DSP控(kong)(kong)制(zhi)采(cai)(cai)樣周(zhou)期即是交流(liu)(liu)電(dian)(dian)(dian)源周(zhou)期的交流(liu)(liu)控(kong)(kong)制(zhi)系統(tong)中，采(cai)(cai)用(yong)變速積分PI調(diao)節更易(yi)獲得小超(chao)調(diao)、無振蕩、無靜差的控(kong)(kong)制(zhi)性能(neng)指標(biao)。該設計系統(tong)可攜(xie)帶15路3A蓄(xu)(xu)電(dian)(dian)(dian)池組(zu)(zu)(每(mei)組(zu)(zu)12V蓄(xu)(xu)電(dian)(dian)(dian)池15節串聯)進(jin)行充放電(dian)(dian)(dian)子系統(tong)工作(zuo)，每(mei)路工作(zuo)由工控(kong)(kong)機編(bian)程(cheng)獨立(li)控(kong)(kong)制(zhi)。通過對充電(dian)(dian)(dian)組(zu)(zu)和(he)放電(dian)(dian)(dian)組(zu)(zu)的公道配置，可獲得明(ming)顯(xian)的節能(neng)效(xiao)果。