賦(fu)能(neng)工業智能(neng)化升級 | 基(ji)于ACM32 MCU的工業通用變頻器(qi)方案
近年來,隨著智能(neng)(neng)制造對(dui)節能(neng)(neng)的(de)更高(gao)要求,通(tong)用變頻(pin)(pin)器在工業領域(yu)的(de)應用愈加廣泛(fan)。變頻(pin)(pin)器是一種先進的(de)調(diao)(diao)速(su)控制設(she)備,通(tong)過對(dui)電源頻(pin)(pin)率的(de)控制可以實現對(dui)電機轉速(su)的(de)精確(que)調(diao)(diao)節,從而提高(gao)設(she)備的(de)性能(neng)(neng)和節能(neng)(neng)效果。
變頻器(qi)概述
變頻器(Variable-Frequency Drive,VFD)是(shi)應用變頻技(ji)術和微電(dian)(dian)子技(ji)術,通過改變電(dian)(dian)機工(gong)作電(dian)(dian)源頻率方式來控制(zhi)交流電(dian)(dian)動(dong)機的電(dian)(dian)動(dong)設備。
對于交(jiao)流電機(ji)而言,其轉速表(biao)達式為:
其中,n表示電(dian)(dian)(dian)(dian)(dian)機的(de)(de)轉(zhuan)速(su)(su),f表示電(dian)(dian)(dian)(dian)(dian)機電(dian)(dian)(dian)(dian)(dian)源(yuan)信號(hao)頻(pin)率,s表示電(dian)(dian)(dian)(dian)(dian)機的(de)(de)轉(zhuan)速(su)(su)差,p表示電(dian)(dian)(dian)(dian)(dian)機的(de)(de)極對(dui)數。從上式可以(yi)看出,電(dian)(dian)(dian)(dian)(dian)機的(de)(de)轉(zhuan)速(su)(su)和電(dian)(dian)(dian)(dian)(dian)源(yuan)信號(hao)頻(pin)率成正比關系。因此,只更改頻(pin)率即(ji)可改變(bian)(bian)(bian)電(dian)(dian)(dian)(dian)(dian)機的(de)(de)轉(zhuan)速(su)(su)。變(bian)(bian)(bian)頻(pin)器正是依據該公(gong)式來實(shi)現對(dui)電(dian)(dian)(dian)(dian)(dian)機的(de)(de)變(bian)(bian)(bian)速(su)(su)控制(zhi)。通(tong)常,變(bian)(bian)(bian)頻(pin)器由(you)整流(liu)(liu)電(dian)(dian)(dian)(dian)(dian)路(lu)(lu)(lu),濾波電(dian)(dian)(dian)(dian)(dian)路(lu)(lu)(lu),逆(ni)變(bian)(bian)(bian)電(dian)(dian)(dian)(dian)(dian)路(lu)(lu)(lu)以(yi)及控制(zhi)電(dian)(dian)(dian)(dian)(dian)路(lu)(lu)(lu)4個部分組(zu)成。外部輸入的(de)(de)三相電(dian)(dian)(dian)(dian)(dian)會經(jing)過整流(liu)(liu)電(dian)(dian)(dian)(dian)(dian)路(lu)(lu)(lu)和濾波電(dian)(dian)(dian)(dian)(dian)路(lu)(lu)(lu)得到穩定的(de)(de)直流(liu)(liu)電(dian)(dian)(dian)(dian)(dian)。直流(liu)(liu)電(dian)(dian)(dian)(dian)(dian)再通(tong)過逆(ni)變(bian)(bian)(bian)電(dian)(dian)(dian)(dian)(dian)路(lu)(lu)(lu)得到用以(yi)驅動交(jiao)流(liu)(liu)電(dian)(dian)(dian)(dian)(dian)機的(de)(de)三相電(dian)(dian)(dian)(dian)(dian)。逆(ni)變(bian)(bian)(bian)電(dian)(dian)(dian)(dian)(dian)路(lu)(lu)(lu)一般會選用IGBT來實(shi)現,以(yi)期(qi)得到足(zu)夠的(de)(de)驅動電(dian)(dian)(dian)(dian)(dian)流(liu)(liu),其電(dian)(dian)(dian)(dian)(dian)路(lu)(lu)(lu)結構示意(yi)圖(tu)如下圖(tu)所示:
逆(ni)變電(dian)路結構示(shi)意圖(tu)
經過(guo)整形和濾波之(zhi)后的(de)直流信(xin)號接(jie)入到(dao)上(shang)圖(tu)的(de)環境V+和V-端,控制電(dian)路通過(guo)Y1~Y6端口(kou),控制IGBT的(de)開關得到(dao)交流電(dian)機的(de)三相交流控制信(xin)號,以完成(cheng)對電(dian)機的(de)控制。
航(hang)芯ACM32 MCU工(gong)業變頻器方案
針對工(gong)業自動化電機(ji)驅(qu)動需求(qiu)的(de)(de)(de)客戶(hu),上海(hai)航芯推出了(le)工(gong)業通用變頻器(qi)應用方案,該方案采(cai)用ACM32F4/ACM32G1系列MCU,最高(gao)(gao)(gao)工(gong)作頻率(lv)可達180MHz/120MHz,內置最大512KB的(de)(de)(de)eFlash和最大192KB SRAM。其(qi)中ACM32F4帶(dai)有一個可輸(shu)出4路帶(dai)死(si)區的(de)(de)(de)互補PWM信(xin)號的(de)(de)(de)高(gao)(gao)(gao)級定(ding)時器(qi)以及采(cai)樣速(su)率(lv)最高(gao)(gao)(gao)可到2Msps的(de)(de)(de)12位(wei)(wei)ADC。而ACM32G1帶(dai)有兩個可輸(shu)出4路帶(dai)死(si)區的(de)(de)(de)互補PWM信(xin)號的(de)(de)(de)高(gao)(gao)(gao)級定(ding)時器(qi)以及兩路采(cai)樣速(su)率(lv)最高(gao)(gao)(gao)可到3Msps的(de)(de)(de)12位(wei)(wei)ADC。可實現高(gao)(gao)(gao)性能、高(gao)(gao)(gao)精(jing)度的(de)(de)(de)電機(ji)驅(qu)動控制,是工(gong)業設備(bei)電機(ji)驅(qu)動控制應用的(de)(de)(de)理想選擇。
基于ACM32F4/ACM32G1系列(lie)MCU的控制(zhi)電路結構框圖(tu),如下圖(tu)所示:
控制電(dian)路的顯示(shi)(shi)輸出,采用(yong)SPI接(jie)口的LED顯示(shi)(shi)屏。ACM32F4/ACM32G1系列的MCU,其標(biao)準SPI通(tong)信速率可到(dao)(dao)50MHz,能(neng)及時(shi)將(jiang)顯示(shi)(shi)數據刷新到(dao)(dao)LED顯示(shi)(shi)屏上(shang)。變(bian)頻器的設置(zhi)參數有兩(liang)種設置(zhi)模式,在(zai)脫機(ji)情況(kuang)下,用(yong)戶(hu)可以通(tong)過外部按鍵來設置(zhi)工作(zuo)(zuo)參數。而(er)在(zai)線模式下,變(bian)頻器通(tong)過UART接(jie)口和上(shang)位機(ji)相連。用(yong)戶(hu)通(tong)過上(shang)位機(ji)將(jiang)設定的工作(zuo)(zuo)參數輸入至(zhi)設備中,設備運行時(shi),也會(hui)將(jiang)實時(shi)工作(zuo)(zuo)情況(kuang)反饋給上(shang)位機(ji),以便用(yong)戶(hu)對設備進行實時(shi)調整。
逆變電路(lu)部分的(de)控(kong)制(zhi)(zhi)是整個控(kong)制(zhi)(zhi)邏輯中(zhong)的(de)核(he)心(xin)部分,其本質是通過MCU中(zhong)的(de)高級定時器輸出(chu)3對互補PWM信號給到(dao)Y1~Y6。利用(yong)(yong)SPWM技術(shu)驅動(dong)輸出(chu)三(san)相交(jiao)(jiao)(jiao)流信號來控(kong)制(zhi)(zhi)電機工作(zuo)。而三(san)相交(jiao)(jiao)(jiao)流電的(de)換相操作(zuo),則是根據MCU內置的(de)12位的(de)ADC對U,V和W三(san)項進行電流采(cai)樣(yang)來判(pan)定換項的(de)時間。ACM32F4系列(lie)的(de)MCU,ADC的(de)采(cai)樣(yang)頻(pin)率(lv)能(neng)到(dao)2Msps,能(neng)滿足大多數(shu)設備的(de)運行需(xu)求。而面對高性(xing)能(neng)需(xu)要的(de)應用(yong)(yong)場(chang)合,則可使用(yong)(yong)ACM32G1系列(lie)MCU。該系列(lie)MCU有兩(liang)路(lu)ADC,最高采(cai)樣(yang)率(lv)為3Msps,采(cai)用(yong)(yong)交(jiao)(jiao)(jiao)叉采(cai)樣(yang)方式提高對信號的(de)采(cai)樣(yang)速(su)率(lv),精確控(kong)制(zhi)(zhi)換相參數(shu)并做出(chu)相應的(de)控(kong)制(zhi)(zhi)動(dong)作(zuo)。