基于DSP的蓄(xu)電(dian)池充放(fang)電(dian)裝置原理

1 引言

在蓄(xu)(xu)電(dian)(dian)(dian)池(chi)生產(chan)過(guo)程中(zhong)，為了保證產(chan)品(pin)質量，常需對(dui)成品(pin)蓄(xu)(xu)電(dian)(dian)(dian)池(chi)進(jin)行幾次充(chong)放(fang)電(dian)(dian)(dian)處理(li)(li)。傳統充(chong)放(fang)電(dian)(dian)(dian)設(she)備通常采用(yong)晶閘管作為整流逆變(bian)功率器(qi)件。裝(zhuang)置比較復雜，交流輸進(jin)、輸出的(de)(de)(de)(de)功率因數較低。對(dui)電(dian)(dian)(dian)網的(de)(de)(de)(de)諧波污染(ran)也比較大。為此，設(she)計(ji)了一種三相SPWM整流逆變(bian)蓄(xu)(xu)電(dian)(dian)(dian)池(chi)充(chong)放(fang)電(dian)(dian)(dian)裝(zhuang)置。它(ta)采用(yong)IGBT作為功率變(bian)換(huan)器(qi)件。交流側以精密鎖相的(de)(de)(de)(de)正弦(xian)波電(dian)(dian)(dian)流實現電(dian)(dian)(dian)能變(bian)換(huan)。可獲接近于(yu)1的(de)(de)(de)(de)功率因數，實現對(dui)蓄(xu)(xu)電(dian)(dian)(dian)池(chi)的(de)(de)(de)(de)充(chong)放(fang)電(dian)(dian)(dian)處理(li)(li)，明(ming)顯降(jiang)低了對(dui)電(dian)(dian)(dian)網的(de)(de)(de)(de)諧波污染(ran)，滿足了綠色環(huan)保和節能的(de)(de)(de)(de)設(she)計(ji)要求。

2 系統結構及工作原理

圖1示(shi)出設計的(de)(de)蓄電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)生產用(yong)充放(fang)(fang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)控(kong)(kong)制(zhi)(zhi)系(xi)統(tong)結(jie)構。該系(xi)統(tong)從原理(li)上可劃分為SPWM雙向逆變(bian)和(he)(he)DC／DC變(bian)換(huan)(huan)充放(fang)(fang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)兩(liang)個子(zi)系(xi)統(tong)。前(qian)者(zhe)，在(zai)蓄電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)充電(dian)(dian)(dian)(dian)(dian)(dian)(dian)時，通過(guo)三相(xiang)PFC升壓(ya)控(kong)(kong)制(zhi)(zhi)實(shi)現(xian)AC／DC變(bian)換(huan)(huan)。將交流電(dian)(dian)(dian)(dian)(dian)(dian)(dian)網電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)轉換(huan)(huan)成蓄電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)充電(dian)(dian)(dian)(dian)(dian)(dian)(dian)所需的(de)(de)直(zhi)(zhi)(zhi)流電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)；在(zai)蓄電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)放(fang)(fang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)時，通過(guo)三相(xiang)PFC恒壓(ya)逆變(bian)控(kong)(kong)制(zhi)(zhi)實(shi)現(xian)DC／AC變(bian)換(huan)(huan)，將蓄電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)開釋(shi)的(de)(de)能量(liang)回饋(kui)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)網。后者(zhe)，完成逆變(bian)直(zhi)(zhi)(zhi)流電(dian)(dian)(dian)(dian)(dian)(dian)(dian)能與蓄電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)能的(de)(de)轉換(huan)(huan)，以保證蓄電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)充放(fang)(fang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)過(guo)程(cheng)中所要求的(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)流、電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)和(he)(he)時間的(de)(de)控(kong)(kong)制(zhi)(zhi)。各子(zi)系(xi)統(tong)采用(yong)單獨的(de)(de)DSP治理(li)，DSP部分以模(mo)板化直(zhi)(zhi)(zhi)插(cha)結(jie)構直(zhi)(zhi)(zhi)接(jie)插(cha)進工(gong)控(kong)(kong)機(ji)的(de)(de)主(zhu)板，工(gong)控(kong)(kong)機(ji)承擔整個系(xi)統(tong)的(de)(de)監控(kong)(kong)治理(li)。系(xi)統(tong)由1個逆變(bian)子(zi)系(xi)統(tong)和(he)(he)n個(實(shi)驗樣(yang)機(ji)設計為15個)充放(fang)(fang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)子(zi)系(xi)統(tong)組(zu)成。系(xi)統(tong)工(gong)作(zuo)時，可通過(guo)工(gong)控(kong)(kong)機(ji)編組(zu)，使后路(lu)蓄電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)工(gong)作(zuo)于(yu)充電(dian)(dian)(dian)(dian)(dian)(dian)(dian)狀態(tai)(tai)；n-k路(lu)工(gong)作(zuo)于(yu)放(fang)(fang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)狀態(tai)(tai)，這樣(yang)蓄電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池(chi)(chi)(chi)能量(liang)就可直(zhi)(zhi)(zhi)接(jie)在(zai)系(xi)統(tong)內部進行交換(huan)(huan)，從而明顯進步了節能效果。圖2示(shi)出三相(xiang)SPWM雙向逆變(bian)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)采用(yong)的(de)(de)典(dian)型電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)型結(jie)構主(zhu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)路(lu)。

三相(xiang)反饋電(dian)(dian)(dian)(dian)流(liu)(liu)iuf，ivf，iwf用(yong)于跟蹤由DSP產(chan)生的電(dian)(dian)(dian)(dian)流(liu)(liu)給定(ding)信號，從而控(kong)制直(zhi)流(liu)(liu)端電(dian)(dian)(dian)(dian)壓Ud的穩定(ding)；Ud的反饋電(dian)(dian)(dian)(dian)壓Ut的值經DSP采(cai)樣后通過電(dian)(dian)(dian)(dian)壓調節得到(dao)作用(yong)于電(dian)(dian)(dian)(dian)流(liu)(liu)內環的電(dian)(dian)(dian)(dian)流(liu)(liu)給定(ding)值。

圖(tu)3示出單(dan)相(xiang)PWM整流電(dian)路(lu)的相(xiang)量圖(tu)[2]。固然(ran)該(gai)系統采用的是三(san)相(xiang)PWM整流電(dian)路(lu)．但其工作原(yuan)理與(yu)(yu)單(dan)相(xiang)電(dian)路(lu)相(xiang)似，只是從單(dan)相(xiang)擴(kuo)展到三(san)相(xiang)。對電(dian)路(lu)進(jin)(jin)行SPWM控制(zhi)，在橋的交流輸進(jin)(jin)端(duan)A，B，C可得到三(san)相(xiang)橋臂的SPWM電(dian)壓uiu，uiv，uiw。對其各相(xiang)按圖(tu)3的相(xiang)量圖(tu)進(jin)(jin)行控制(zhi)，就可使各相(xiang)電(dian)流iu，iv，iw為正弦波。且與(yu)(yu)電(dian)壓同相(xiang)位(wei)，功率(lv)因數近似為1。

由(you)此可(ke)知，控制uiu的(de)大(da)(da)小(xiao)和(he)相位δ即(ji)可(ke)控制電(dian)流的(de)大(da)(da)小(xiao)和(he)流向(xiang)，從而控制功率的(de)大(da)(da)小(xiao)和(he)方向(xiang)。通過對Ud的(de)恒壓控制，實現逆變器的(de)功率流向(xiang)，從而實現能(neng)量的(de)自(zi)動雙向(xiang)活動。

3 電壓控制器的設計

圖(tu)4示出AD／DC逆變控(kong)制(zhi)(zhi)框(kuang)圖(tu)。該系(xi)統采(cai)用(yong)電壓、電流(liu)(liu)雙閉環控(kong)制(zhi)(zhi)結構，其電壓控(kong)制(zhi)(zhi)對(dui)(dui)象為直流(liu)(liu)量(liang)；電流(liu)(liu)控(kong)制(zhi)(zhi)對(dui)(dui)象為交(jiao)流(liu)(liu)量(liang)。電壓外環采(cai)用(yong)數字算法予(yu)以實(shi)現；電流(liu)(liu)內環采(cai)用(yong)模擬電路予(yu)以實(shi)現，以確(que)保(bao)快速進行電流(liu)(liu)控(kong)制(zhi)(zhi)，進步系(xi)統工作(zuo)的(de)可(ke)靠性。同(tong)時，為了使誤差電流(liu)(liu)與給定相位(wei)保(bao)持一致。電流(liu)(liu)調節器采(cai)用(yong)比例控(kong)制(zhi)(zhi)。

蓄(xu)(xu)電(dian)(dian)(dian)(dian)池(chi)充電(dian)(dian)(dian)(dian)時(shi)，輸出電(dian)(dian)(dian)(dian)壓(ya)(ya)Ud低于(yu)給定(ding)值(zhi)(zhi)Ud*，則電(dian)(dian)(dian)(dian)壓(ya)(ya)調(diao)節器(qi)(qi)輸出正(zheng)的(de)(de)(de)uc，輸進電(dian)(dian)(dian)(dian)壓(ya)(ya)Uin經過一個(ge)比例因(yin)(yin)子Ku后(hou)得到(dao)一個(ge)與(yu)(yu)Uin同(tong)相的(de)(de)(de)單位正(zheng)弦(xian)us，uc與(yu)(yu)us的(de)(de)(de)乘積作為給定(ding)電(dian)(dian)(dian)(dian)流i*，與(yu)(yu)Uin同(tong)相，控制i跟(gen)隨i*，則能(neng)量就(jiu)以(yi)單位功(gong)(gong)率(lv)(lv)(lv)因(yin)(yin)數從(cong)電(dian)(dian)(dian)(dian)網流向(xiang)(xiang)蓄(xu)(xu)電(dian)(dian)(dian)(dian)池(chi)。此(ci)時(shi)，變(bian)流器(qi)(qi)工(gong)作在(zai)整流狀態。蓄(xu)(xu)電(dian)(dian)(dian)(dian)池(chi)放(fang)電(dian)(dian)(dian)(dian)時(shi)，Ud高于(yu)Ud*，則uc為負值(zhi)(zhi)，uc與(yu)(yu)us相乘得到(dao)與(yu)(yu)Uin反向(xiang)(xiang)的(de)(de)(de)給定(ding)電(dian)(dian)(dian)(dian)流i*，控制i跟(gen)隨i*，能(neng)量就(jiu)能(neng)以(yi)單位功(gong)(gong)率(lv)(lv)(lv)因(yin)(yin)數從(cong)蓄(xu)(xu)電(dian)(dian)(dian)(dian)池(chi)流向(xiang)(xiang)電(dian)(dian)(dian)(dian)網。此(ci)時(shi)，變(bian)流器(qi)(qi)工(gong)作在(zai)逆變(bian)狀態。電(dian)(dian)(dian)(dian)壓(ya)(ya)外環產生輸進給定(ding)電(dian)(dian)(dian)(dian)流i*，其幅(fu)值(zhi)(zhi)表明了功(gong)(gong)率(lv)(lv)(lv)的(de)(de)(de)大小；符號決(jue)定(ding)了功(gong)(gong)率(lv)(lv)(lv)的(de)(de)(de)流向(xiang)(xiang)；相位決(jue)定(ding)了能(neng)量傳遞的(de)(de)(de)功(gong)(gong)率(lv)(lv)(lv)因(yin)(yin)數。電(dian)(dian)(dian)(dian)流內環使(shi)輸進電(dian)(dian)(dian)(dian)流跟(gen)蹤(zong)給定(ding)，從(cong)而(er)實(shi)現可逆的(de)(de)(de)單位功(gong)(gong)率(lv)(lv)(lv)因(yin)(yin)數變(bian)換。

系(xi)統采用TMS320LF2407A DSP作為主處理器(qi)，因其有豐富的外設和較高的運算速度(du)。由此可實現較復雜的控(kong)制(zhi)及高精度(du)的數據處理。在此，通(tong)過(guo)對PI控(kong)制(zhi)、IP控(kong)制(zhi)和變(bian)速積分(fen)PI控(kong)制(zhi)三種電(dian)壓調節(jie)器(qi)算法(fa)(fa)的實驗得出(chu)其優(you)劣，從而(er)選(xuan)擇最適合該系(xi)統的控(kong)制(zhi)算法(fa)(fa)進行電(dian)壓調節(jie)。

(1)PI控制算法和IP控制算法

圖5a示(shi)出(chu)PI調節(jie)器(qi)結構圖。由圖可(ke)得其傳遞

比(bi)(bi)較式(5)和(he)式(6)可(ke)(ke)見，兩種系(xi)統的傳(chuan)遞(di)函(han)數分母相同(tong)，故(gu)IP調(diao)節器可(ke)(ke)持有與PI相同(tong)的無靜(jing)差調(diao)節和(he)穩定特性(xing)，同(tong)時因它在傳(chuan)遞(di)函(han)數上比(bi)(bi)PI少一個零點，因此具(ju)有比(bi)(bi)PI更(geng)好的高頻衰減特性(xing)，輕(qing)易(yi)滿足(zu)較長采樣周期數字調(diao)節的穩定性(xing)要求，能有效抑(yi)制混迭現象。系(xi)統實(shi)驗(yan)證實(shi)，采用(yong)IP調(diao)節，調(diao)節器參(can)數很輕(qing)易(yi)整定。可(ke)(ke)使系(xi)統達(da)到穩定、無靜(jing)差和(he)很小的超調(diao)。不過在快速(su)性(xing)方面(mian)將有損(sun)失。

(2)變速積分PI控制算法

在傳統的(de)(de)PI算法中，因積(ji)(ji)(ji)分(fen)(fen)(fen)增(zeng)益Ki為常數，在整個調節過程中，其值不變(bian)。但系(xi)統對(dui)積(ji)(ji)(ji)分(fen)(fen)(fen)的(de)(de)要求是(shi)偏(pian)差(cha)大時，積(ji)(ji)(ji)分(fen)(fen)(fen)作用(yong)減(jian)弱(ruo)，否則(ze)(ze)會(hui)產生超(chao)調，甚至出現積(ji)(ji)(ji)分(fen)(fen)(fen)飽和；反(fan)之則(ze)(ze)加強(qiang)，否則(ze)(ze)不能(neng)滿(man)足(zu)(zu)正確性(xing)的(de)(de)要求。引(yin)進變(bian)速積(ji)(ji)(ji)分(fen)(fen)(fen)PI控制算法能(neng)使(shi)控制性(xing)能(neng)得以(yi)滿(man)足(zu)(zu)。其基本思路是(shi)偏(pian)差(cha)大時，積(ji)(ji)(ji)分(fen)(fen)(fen)累(lei)積(ji)(ji)(ji)速度慢，積(ji)(ji)(ji)分(fen)(fen)(fen)作用(yong)弱(ruo)；偏(pian)差(cha)小(xiao)時，積(ji)(ji)(ji)分(fen)(fen)(fen)累(lei)積(ji)(ji)(ji)速度快，積(ji)(ji)(ji)分(fen)(fen)(fen)作用(yong)強(qiang)。為此，設置系(xi)數f[E(k)]，它是(shi)偏(pian)差(cha)E(k)的(de)(de)函數，當E(k)增(zeng)大時，f[E(k)]減(jian)小(xiao)；反(fan)之則(ze)(ze)增(zeng)大。每(mei)次采(cai)樣后，用(yong)f[E(k)]乘E(k)，再進行累(lei)加。f[E(k)]與E(k)的(de)(de)關系(xi)可表示(shi)為：

在(zai)該系(xi)統(tong)中，采用(yong)簡單的(de)變(bian)速(su)積(ji)(ji)分PI控制，取A=32，B=8，當(dang)誤(wu)差(cha)(cha)大于40時，系(xi)統(tong)相當(dang)于采用(yong)純比例調(diao)節，因此(ci)響應(ying)速(su)度加快(kuai)；當(dang)誤(wu)差(cha)(cha)小(xiao)于40并減小(xiao)到8的(de)過程中，積(ji)(ji)分作(zuo)用(yong)開(kai)始(shi)并逐漸(jian)增強，響應(ying)過程快(kuai)速(su)平滑；當(dang)誤(wu)差(cha)(cha)小(xiao)于8時，完全引進積(ji)(ji)分作(zuo)用(yong)，能快(kuai)速(su)有效(xiao)(xiao)地消除靜(jing)差(cha)(cha)。該方法可有效(xiao)(xiao)抑制系(xi)統(tong)的(de)超調(diao)，同時也可兼顧系(xi)統(tong)的(de)響應(ying)速(su)度。

4 實驗結果

利用PI，IP和變速(su)(su)積分PI數字電壓(ya)(ya)調(diao)(diao)(diao)(diao)節(jie)器的(de)(de)(de)逆變子系(xi)統(tong)對該設計(ji)方案進行了大量實驗。結(jie)果可見(jian)，采(cai)用變速(su)(su)積分PI數字電壓(ya)(ya)調(diao)(diao)(diao)(diao)節(jie)器的(de)(de)(de)綜合性(xing)(xing)能優于前兩種算法(fa)。圖(tu)6示出采(cai)用PI調(diao)(diao)(diao)(diao)節(jie)、IP調(diao)(diao)(diao)(diao)節(jie)，以及(ji)變速(su)(su)積分PI調(diao)(diao)(diao)(diao)節(jie)時用100M-Tektronix TDS220存儲(chu)示波器獲取的(de)(de)(de)一(yi)組直流母線(xian)電壓(ya)(ya)Ud的(de)(de)(de)實驗對比波形。逆變器起動(dong)時Ud由(you)150V升至(zhi)200V。由(you)圖(tu)6可見(jian)。3種調(diao)(diao)(diao)(diao)節(jie)器在無靜差調(diao)(diao)(diao)(diao)節(jie)方面(mian)的(de)(de)(de)性(xing)(xing)能相同，而(er)IP的(de)(de)(de)上升時間明顯大于另外兩種算法(fa)；在抑(yi)制(zhi)超(chao)(chao)調(diao)(diao)(diao)(diao)及(ji)高(gao)頻噪聲誘發(fa)振(zhen)蕩方面(mian)，變速(su)(su)積分PI法(fa)有著明顯的(de)(de)(de)上風，PI系(xi)統(tong)的(de)(de)(de)起動(dong)超(chao)(chao)調(diao)(diao)(diao)(diao)超(chao)(chao)過20V，IP系(xi)統(tong)的(de)(de)(de)超(chao)(chao)調(diao)(diao)(diao)(diao)不到10V，而(er)變速(su)(su)積分PI系(xi)統(tong)則無超(chao)(chao)調(diao)(diao)(diao)(diao)。無振(zhen)蕩，能很快進進穩定狀態：在抗干擾性(xing)(xing)能方面(mian)，變速(su)(su)積分PI系(xi)統(tong)也具有同樣的(de)(de)(de)特點。

5 結論

先容的(de)逆變(bian)器采用了直流(liu)母線電(dian)壓(ya)的(de)恒壓(ya)數字調(diao)節(jie)，可(ke)(ke)方(fang)便地(di)實現電(dian)網能量(liang)和蓄(xu)電(dian)池(chi)能量(liang)的(de)雙(shuang)向活動，精密鎖相的(de)SPWM控(kong)(kong)制(zhi)可(ke)(ke)獲得(de)(de)接近于1的(de)功(gong)率(lv)因數，理(li)論分析和系(xi)(xi)統實驗表明，在DSP控(kong)(kong)制(zhi)采樣周(zhou)期(qi)即(ji)是交流(liu)電(dian)源周(zhou)期(qi)的(de)交流(liu)控(kong)(kong)制(zhi)系(xi)(xi)統中，采用變(bian)速積分PI調(diao)節(jie)更易獲得(de)(de)小超(chao)調(diao)、無(wu)(wu)振蕩、無(wu)(wu)靜差的(de)控(kong)(kong)制(zhi)性能指標。該設計(ji)系(xi)(xi)統可(ke)(ke)攜(xie)帶(dai)15路3A蓄(xu)電(dian)池(chi)組(zu)(每組(zu)12V蓄(xu)電(dian)池(chi)15節(jie)串聯)進行充放(fang)電(dian)子系(xi)(xi)統工作，每路工作由工控(kong)(kong)機編程(cheng)獨立控(kong)(kong)制(zhi)。通過對充電(dian)組(zu)和放(fang)電(dian)組(zu)的(de)公道配置，可(ke)(ke)獲得(de)(de)明顯的(de)節(jie)能效果。