PTS-系列之PEK-100系列教學
PEK-120模塊之PV充電器

寫在前面(mian)的話(hua)

經過前幾期(qi)(qi)對(dui)于PTS-800中基本(ben)的(de)電路圖拓(tuo)撲(pu)結(jie)(jie)構的(de)學習，我(wo)們已經掌握(wo)了基本(ben)的(de)電路模型。從PEK-100系(xi)列開始，在固有電路拓(tuo)撲(pu)基礎上開始對(dui)電路的(de)控制方式(shi)進行學習。本(ben)期(qi)(qi)將針(zhen)對(dui)直流變換(huan)器PEK-120的(de)控制方式(shi)以(yi)及與新能(neng)源中光伏發(fa)電結(jie)(jie)合探究最(zui)大(da)功率點追蹤技(ji)術的(de)學習。

PEK-120
降壓式(shi)轉換(huan)器(qi)模組

簡 述：

下(xia)圖所(suo)(suo)示為(wei)PV充(chong)電(dian)(dian)(dian)系(xi)統之三種工作(zuo)模(mo)(mo)式(shi)，圖(a)為(wei)MPPT模(mo)(mo)式(shi)，當(dang)(dang)PV模(mo)(mo)組電(dian)(dian)(dian)力(li)(li)不足(zu)供給(gei)負(fu)(fu)載或充(chong)電(dian)(dian)(dian)使用(yong)時，其不足(zu)部分將(jiang)由蓄電(dian)(dian)(dian)池供給(gei)；圖(b)為(wei)部分充(chong)電(dian)(dian)(dian)模(mo)(mo)式(shi)，當(dang)(dang)PV模(mo)(mo)組電(dian)(dian)(dian)力(li)(li)足(zu)夠供給(gei)負(fu)(fu)載使用(yong)，且多余(yu)之電(dian)(dian)(dian)力(li)(li)還可對蓄電(dian)(dian)(dian)池進行(xing)充(chong)電(dian)(dian)(dian)，但(dan)所(suo)(suo)多余(yu)電(dian)(dian)(dian)力(li)(li)仍不足(zu)以最大(da)充(chong)電(dian)(dian)(dian)電(dian)(dian)(dian)流對蓄電(dian)(dian)(dian)池充(chong)電(dian)(dian)(dian)，以上兩種模(mo)(mo)式(shi)均操作(zuo)于最大(da)功(gong)率(lv)點(dian)(dian)。圖(c)為(wei)MPPT偏(pian)移模(mo)(mo)式(shi)，當(dang)(dang)PV模(mo)(mo)組操作(zuo)于最大(da)功(gong)率(lv)點(dian)(dian)時，其總(zong)輸出(chu)電(dian)(dian)(dian)力(li)(li)大(da)于負(fu)(fu)載及蓄電(dian)(dian)(dian)池需求(qiu)總(zong)和，為(wei)求(qiu)電(dian)(dian)(dian)力(li)(li)平衡情況(kuang)下(xia)，必須降低PV模(mo)(mo)組總(zong)輸出(chu)電(dian)(dian)(dian)力(li)(li)，此(ci)時PV模(mo)(mo)組必須偏(pian)離(li)其最大(da)功(gong)率(lv)點(dian)(dian)以降低所(suo)(suo)產(chan)生(sheng)之電(dian)(dian)(dian)力(li)(li)，來達(da)到電(dian)(dian)(dian)力(li)(li)平衡。

控(kong)制架構(gou)：

為實現上述工作模式(shi)，PV充電系統控制(zhi)(zhi)(zhi)架(jia)構安排如(ru)下(xia)圖所示，其采用雙回(hui)路控制(zhi)(zhi)(zhi)，外回(hui)路為充電控制(zhi)(zhi)(zhi)回(hui)路，內回(hui)路包含MPPT控制(zhi)(zhi)(zhi)回(hui)路與PV電壓(ya)控制(zhi)(zhi)(zhi)回(hui)路，其控制(zhi)(zhi)(zhi)原理如(ru)下(xia)：

首先取樣蓄(xu)電(dian)(dian)(dian)(dian)池(chi)(chi)電(dian)(dian)(dian)(dian)壓(Vb)與(yu)蓄(xu)電(dian)(dian)(dian)(dian)池(chi)(chi)最大電(dian)(dian)(dian)(dian)壓命(ming)令(Vb*)比較(jiao)，其(qi)誤差(cha)經(jing)由PI控制(zhi)器與(yu)正向限制(zhi)器后(hou)可得到(dao)充電(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)流(liu)(liu)命(ming)令(Ib*)，當蓄(xu)電(dian)(dian)(dian)(dian)池(chi)(chi)電(dian)(dian)(dian)(dian)壓未達到(dao)最大電(dian)(dian)(dian)(dian)壓命(ming)令時(shi)，此限制(zhi)器用以設定(ding)(ding)最大充電(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)流(liu)(liu)；當蓄(xu)電(dian)(dian)(dian)(dian)池(chi)(chi)電(dian)(dian)(dian)(dian)壓接近于最大電(dian)(dian)(dian)(dian)壓命(ming)令時(shi)，控制(zhi)器便進入線性區(qu)，使得充電(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)流(liu)(liu)命(ming)令減(jian)少(shao)，最終將達到(dao)電(dian)(dian)(dian)(dian)池(chi)(chi)最大電(dian)(dian)(dian)(dian)壓命(ming)令準位且使充電(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)流(liu)(liu)僅提(ti)供電(dian)(dian)(dian)(dian)池(chi)(chi)本身(shen)之消耗。此方法可達到(dao)定(ding)(ding)電(dian)(dian)(dian)(dian)流(liu)(liu)充電(dian)(dian)(dian)(dian)、定(ding)(ding)電(dian)(dian)(dian)(dian)壓充電(dian)(dian)(dian)(dian)及浮充等(deng)三階段充電(dian)(dian)(dian)(dian)之目的來增(zeng)長電(dian)(dian)(dian)(dian)池(chi)(chi)壽(shou)命(ming)。

由PI電壓控制器產生之充電電流命令(Ib*)與蓄電池電流(Ib)比較，當Ib>Ib*時，其誤差經由PI控制器與正向為零之限制器后產生一電壓命令(VL)，此電壓命令(VL)將會影響其最大功率點，使得最大功率點偏向右半面曲線，提升PV模組輸出電壓，最終使PV模組所產生輸出功率為負載和蓄電池需求總合，以達到電力平衡，此情形發生于MPPT偏移模式。反之，當Ib

依據上述方法，本實(shi)驗電(dian)(dian)池(chi)(chi)三(san)階段(duan)充(chong)電(dian)(dian)策略之(zhi)設定(ding)(ding)如下，其中Ich,max乃根據電(dian)(dian)池(chi)(chi)形式及容量所(suo)設定(ding)(ding)之(zhi)最大充(chong)電(dian)(dian)電(dian)(dian)流：

定(ding)電流區(qu):Vb≤0.8Vb*

Ib*=Ich,max

定電壓區:0.8Vb*

Ib*=Ich,max~0.1Ich,max(視電池(chi)電壓線性調(diao)整(zheng))

浮充區:0.95Vb*

Ib*=0.1Ich,max

結合PV控制(zhi)(zhi)器(MPPT采用P&O擾(rao)動觀察法)與充(chong)電(dian)(dian)(dian)控制(zhi)(zhi)器之(zhi)(zhi)模擬電(dian)(dian)(dian)路下(xia)(xia)圖(tu)所示，PV模組之(zhi)(zhi)最(zui)大功(gong)率點設(she)定(ding)為(wei)(wei)Vmp=32V，Imp=3A，Pmp=96W。電(dian)(dian)(dian)池(chi)充(chong)電(dian)(dian)(dian)器之(zhi)(zhi)設(she)定(ding)為(wei)(wei)Vb*=28V，電(dian)(dian)(dian)池(chi)電(dian)(dian)(dian)壓為(wei)(wei)24V，當充(chong)電(dian)(dian)(dian)電(dian)(dian)(dian)流限制(zhi)(zhi)(Ib*)設(she)定(ding)為(wei)(wei)5A時，由于(yu)在此設(she)定(ding)下(xia)(xia)輸出(Pch=24V*5A=120W)超過Pmp，系(xi)統將(jiang)(jiang)操(cao)作于(yu)輸出將(jiang)(jiang)被限制(zhi)(zhi)在Pmp使(shi)PV模組操(cao)作于(yu)最(zui)大功(gong)率點，亦(yi)即前述(shu)之(zhi)(zhi)MPPT模式(shi)(如果(guo)有接上負載的(de)話)亦(yi)或部分充(chong)電(dian)(dian)(dian)模式(shi)，模擬結果(guo)下(xia)(xia)圖(tu)所示，系(xi)統確實操(cao)作于(yu)MPP點。電(dian)(dian)(dian)池(chi)電(dian)(dian)(dian)壓為(wei)(wei)24V，當充(chong)電(dian)(dian)(dian)電(dian)(dian)(dian)流限制(zhi)(zhi)(Ib*)設(she)定(ding)為(wei)(wei)3A時，由于(yu)在此設(she)定(ding)下(xia)(xia)輸出功(gong)率(Pch=24V*3A=72W)低于(yu)Pmp，系(xi)統之(zhi)(zhi)輸出將(jiang)(jiang)由Pch決(jue)定(ding)，MPPT將(jiang)(jiang)產(chan)生偏(pian)移(yi)，亦(yi)即前述(shu)之(zhi)(zhi)MPPT偏(pian)移(yi)模式(shi)，模擬結果(guo)下(xia)(xia)圖(tu)所示，MPP點確實偏(pian)移(yi)，且系(xi)統之(zhi)(zhi)輸出由Pch決(jue)定(ding)。將(jiang)(jiang)輸出之(zhi)(zhi)電(dian)(dian)(dian)池(chi)電(dian)(dian)(dian)壓提高到28V，充(chong)電(dian)(dian)(dian)控制(zhi)(zhi)器將(jiang)(jiang)進入CV模式(shi)，使(shi)Ib*減少，MPPT將(jiang)(jiang)更加偏(pian)移(yi)，PV模組接近開路電(dian)(dian)(dian)壓。

實驗驗證：

充電功率大于最大功率點：

充電(dian)功(gong)率小于最大功(gong)率點：

總(zong)　結：

基于(yu)直(zhi)流變換器的(de)光(guang)伏充電(dian)是新能(neng)源光(guang)伏發電(dian)的(de)必備課程，適用(yong)于(yu)本(ben)科及(ji)研究生階段對光(guang)伏的(de)學(xue)(xue)(xue)習(xi)與(yu)應用(yong)。固(gu)緯電(dian)子在(zai)點力電(dian)子教學(xue)(xue)(xue)方向致力于(yu)為老師減少壓力，緩解(jie)學(xue)(xue)(xue)生的(de)學(xue)(xue)(xue)習(xi)壓力，因此開創了(le)全新的(de)理論與(yu)實踐相結合的(de)教學(xue)(xue)(xue)模式(shi)，還請各位老師同(tong)學(xue)(xue)(xue)進行(xing)了(le)解(jie)轉發。