Umhlinzeki weyunithi ye-frequency converter braking unit ukukhumbuza ukuthi isiguquli se-frequency sifakwe i-resistor eguquguqukayo ikakhulukazi ukuze idle ingxenye yamandla ku-DC bus capacitor ngesinqanda ukubhuleka, ukuze kugwenywe i-voltage eyeqile ye-capacitor. Ngokombono, uma i-capacitor igcina amandla amaningi, ingasetshenziswa ukuyikhulula ukuze ishayele imoto futhi igweme ukuchithwa kwamandla. Kodwa-ke, amandla e-capacitor anomkhawulo, futhi amandla ayo okumelana nawo anqunyelwe. Lapho i-voltage ye-capacitor yebhasi ifinyelela izinga elithile, ingalimaza i-capacitor, futhi abanye bangase balimaze ngisho ne-IGBT. Ngakho-ke, kuyadingeka ukukhulula ugesi nge-resistor braking ngesikhathi esifanele. Lokhu kukhululwa kuwukumosha isikhathi futhi kuyisixazululo esingenakugwenywa.
I-bus capacitor iyi-buffer zone engabamba amandla alinganiselwe
Ngemuva kokuthi wonke amandla e-AC ezigaba ezintathu alungisiwe futhi axhunywe kuma-capacitor, i-voltage evamile yebhasi ngesikhathi sokusebenza okugcwele komthwalo cishe izikhathi ezingu-1.35, 380 * 1.35 = 513 volts. Le voltage izoguquguquka ngokwemvelo ngesikhathi sangempela, kodwa ubuncane abukwazi ukuba ngaphansi kwama-volts angu-480, ngaphandle kwalokho izocupha isivikelo se-alamu ye-undervoltage. Ama-capacitor amabhasi ngokuvamile akhiwa amasethi amabili wama-electrolytic capacitor angu-450V axhunywe ochungechungeni, ane-voltage yokumelana nethiyori engu-900V. Uma i-voltage yebhasi idlula leli nani, i-capacitor izoqhuma ngokuqondile, ngakho-ke i-voltage yebhasi ayikwazi ukufinyelela ku-voltage ephezulu ye-900V kungakhathaliseki ukuthi yini.
Eqinisweni, inani lokumelana ne-voltage ye-IGBT enokufakwa kwezigaba ezintathu ze-380 volt yi-1200 volts, okuvame ukudinga ukusebenza ngaphakathi kwama-volts angu-800. Uma kucatshangelwa ukuthi uma i-voltage ikhuphuka, kuzoba nenkinga ye-inertia, okungukuthi, uma wenza ngokushesha umsebenzi we-braking resistor, i-voltage yebhasi ngeke yehle ngokushesha. Ngakho-ke, iziguquli eziningi zefrikhwensi zenzelwe ukuthi ziqale ukusebenza cishe ngama-volts angama-700 ngeyunithi yokubhuleka ukuze zehlise i-voltage yebhasi futhi zigweme ukushaja okwengeziwe.
Ngakho-ke umnyombo wokuklama ama-resistors ama-braking ukucabangela ukumelana nomthamo wama-capacitor namamojula e-IGBT, ukuze kugwenywe lezi zingxenye ezimbili ezibalulekile ukuthi zingalinyazwa amandla kagesi aphezulu ebhasi. Uma lezi zinhlobo ezimbili zezingxenye zonakalisiwe, isiguquli semvamisa ngeke sisebenze kahle.
Ukupaka okusheshayo kudinga i-resistor yokubhuleka, futhi ukusheshisa okusheshayo nakho kuyakudinga
Isizathu sokuthi kungani i-voltage yebhasi ye-frequency converter inyuka imvamisa ingenxa yesiguquli sefrikhwensi esidala ukuthi injini isebenze esimweni sokubhuleka nge-elekthronikhi, okuvumela i-IGBT ukuthi idlule ekulandeleni okuthile kwe-conduction, isebenzisa i-inductance current enkulu yenjini engakwazi ukushintsha ngokuzumayo, futhi ikhiqize ngokushesha i-voltage ephezulu ukushaja i-capacitor yebhasi. Ngalesi sikhathi, injini yehliswa ngokushesha. Uma i-resistor ye-braking ingawadli amandla ebhasi ngesikhathi esifanele ngalesi sikhathi, i-voltage yebhasi izoqhubeka nokukhuphuka, ibeka usongo ekuphepheni kwesiguquli semvamisa.
Uma umthwalo unganzima kakhulu futhi akukho mfuneko yokumisa ngokushesha, asikho isidingo sokusebenzisa i-resistor braking kulesi simo. Ngisho noma ufaka i-resistor ye-braking, i-voltage ye-threshold esebenzayo yeyunithi ye-braking ngeke iqale, futhi i-resistor yokubopha ngeke isetshenziswe.
Ngaphezu kwesidingo sokwandisa ukumelana ne-braking kanye neyunithi ye-braking ye-braking ngokushesha ezimweni zokunciphisa umthwalo osindayo, empeleni, uma ihlangabezana nezidingo zomthwalo osindayo nesikhathi sokuqala esisheshayo, iyunithi yokubhuleka kanye nokumelana ne-braking nakho kudingeka kuhlanganiswe ukuze kuqalwe. Esikhathini esidlule, ngazama ukusebenzisa i-converter ye-frequency ukuze ngishayele umshini wokunyathelisa okhethekile, futhi isikhathi sokusheshisa se-converter frequency saklanyelwe ukuba sibe imizuzwana engu-0.1. Ngalesi sikhathi, lapho uqala ngomthwalo ogcwele, nakuba umthwalo awunzima kakhulu, ngoba isikhathi sokusheshisa sifushane kakhulu, ukuguquguquka kwe-voltage yebhasi kubi kakhulu, futhi izimo ezingaphezulu noma ezingaphezulu zingenzeka. Kamuva, iyunithi yokubhuleka yangaphandle kanye nokumelana nokubhuleka kwengezwa, futhi isiguquli semvamisa singasebenza ngokujwayelekile. Ekuhlaziyeni, kungenxa yokuthi isikhathi sokuqalisa sifushane kakhulu, futhi i-voltage ye-capacitor yebhasi isuswa ngokushesha. Isilungisisi sishaja umsinga omkhulu ngokushesha, okubangela ugesi webhasi ukuthi ukhuphuke kungazelelwe. Lokhu kubangela ukuguquguquka okukhulu kwamandla kagesi ebhasini, okungase kweqe ama-volts angu-700 ngokuphazima kweso. Ngokungezwa kwe-resistor yokubhuleka, le voltage ephezulu eguquguqukayo ingaqedwa ngesikhathi esifanele, okuvumela isiguquli sefrikhwensi ukuthi sisebenze ngokujwayelekile.
Kukhona futhi isimo esikhethekile ekulawuleni i-vector, lapho i-torque nezinkomba zejubane ze-motor ziphambene, noma uma usebenza ngesivinini se-zero nge-torque engu-100%. Isibonelo, uma i-crane iwisa into esindayo futhi ima emoyeni ophakathi, noma lapho ihlehla, ukulawulwa kwetorque kuyadingeka. I-motor idinga ukusebenza ku-generator state, futhi i-current eqhubekayo izophinde ikhokhiswe ku-capacitor yebhasi. Nge-resistor yokubhuleka, la mandla angadliwa ngesikhathi esifanele ukuze kugcinwe ibhalansi nokuzinza kwe-voltage yebhasi.
Ama-converter amaningi amancane amafrikhwensi, afana nalawo angu-3.7KW, avame ukuba namayunithi okubhuleka akhelwe ngaphakathi kanye nama-resistors amabhuleki, mhlawumbe ngenxa yokucatshangelwa kokunciphisa i-capacitor yebhasi, kuyilapho ama-resistors anamandla aphansi namayunithi okubhuleka awabizi kangako.