GVHD : ThS. L Th Vn AnhSVTH: Lu Thanh Cng ThS.Nguyn Th Hng YnV Vn Cng Phm Th LI NI U Trongqutrnhcngnghiphahinihatnc.Tnghalmt ngnh khng th thiu trong mt nn cng nghip hin i. Ni n t ng ha th my tnh l cng c h tr c lc nht v khng th thiu c trong rt nhiu lnh vc,cbittrongolngviukhin.ngdngmytnhvokthuto lng iu khin em li nhiu kt qu u vit nh chnh xc cao, thi gian thu thp d liu ngn. Cngvisphttrinchungvtrncskinthcchctpti trngchngemchntittnghiplngdngLabVIEWtronghthng iu khin ng c mt chiu. Trong ti ny dng vi iu khin vi Atmega16 thu thp tn hiu encoder t ng c, sau tnh ton tc ri truyn thng ln LabVIEWquachungiaotipRS232.TrnLabVIEWtaxydngbiukhin PID iu khin tc quay ca ng c.LabVIEW l mt mi trng lp trnh cho ngn ng lp trnh ha c s dngrngritrongkhoahc-kthut-giodcnhmnhanhchngvddng to ra cc giao tip my tnh, o lng, m phng h thng, kt ni thit b ngoi vi vimytnhtheothigianthc.LabVIEWrainm1986vngycngpht trin mnh trong lnh vc t ng ha cc h thng o lng v iu khin. Ni dung ti bao gm cc chng: Chng 1: Tng quan v ng c in mt chiu Chng 2: Thit k b iu khin PID cho ng c in mt chiu Chng 3: Gii thiu phn mm LabVIEW Chng 4: M hnh thit k v kt quChng 5: Kt lun v hng pht trin GVHD : ThS. L Th Vn AnhSVTH: Lu Thanh Cng ThS.Nguyn Th Hng YnV Vn Cng Phm Th LI CM N Li u tin chng em xin chn thnh cm n s hng dn nhit tnh ca c L ThVnAnhvcNguynThHngYn.Trongsutqutrnhthchinn cc c dnh rt nhiu thi gian v tm huyt nhhng vgp chng em hon thnh n ny.ChngemcngxinchnthnhcmnnsgipcaBangimhiu TrngiHcinLc,tonthccthycgiotrongKhoaCngNghT ng v bn b trong nhng nm hc va qua. Vi nhng s gip nhit tnh cho chng em c c nn tng kin thc chuyn mn chng em c th hon thnh n ny cng nh cng vic trong tng lai. GVHD : ThS. L Th Vn AnhSVTH: Lu Thanh Cng ThS.Nguyn Th Hng YnV Vn Cng Phm Th NHN XT(Ca ging vin hng dn) GVHD : ThS. L Th Vn AnhSVTH: Lu Thanh Cng ThS.Nguyn Th Hng YnV Vn Cng Phm Th NHN XT (Ca ging vin phn bin) GVHD : ThS. L Th Vn AnhSVTH: Lu Thanh Cng ThS.Nguyn Th Hng YnV Vn Cng Phm Th MC LC CHNG 1: TNG QUAN V NG C IN MT CHIU ........................... 1 1.1 Cu to, phn loi v nguyn l lm vic ca ng c mt chiu .................... 1 1.1.1 Cu to ng c mt chiu ......................................................................... 1 1.1.2 Phn loi ng c mt chiu....................................................................... 4 1.1.3 Nguyn l lm vic ca ng c mt chiu ............................................... 5 1.2 Phm vi ng dng ca ng c mt chiu ........................................................ 6 1.2.1 u im ...................................................................................................... 6 1.2.2 Nhc im ................................................................................................ 6 1.2.3 Phm vi ng dng ....................................................................................... 7 1.3 Cc phng php iu chnh tc ng c mt chiu ................................... 7 1.3.1 Phng php iu chnh in p phn ng ................................................. 7 1.3.2 Phng php iu chnh t thng ............................................................... 9 1.3.3 Phng php iu chnh in tr ph Rf trn mch phn ng ................. 11 CHNG 2: THIT K B IU KHIN PID CHO NG C IN MT CHIU ...................................................................................................................... 13 2.1 M hnh ha ng c mt chiu...................................................................... 13 2.2 Lut iu khin PID ........................................................................................ 18 2.2.1 Gii thiu PID ........................................................................................... 18 2.2.2 Phng php hiu chnh PID bng thc nghim (phng php Ziegler - Nichols). ............................................................................................................. 23 2.3 B iu khin PID cho ng c mt chiu ..................................................... 25 CHNG 3: GII THIU PHN MM LABVIEW ............................................ 28 3.1 Khi qut chung v LabVIEW ........................................................................ 28 3.1.1 u im v nhc im ca LabVIEW ................................................... 28 3.1.2. Phm vi ng dng .................................................................................... 29 3.2 K thut lp trnh LabVIEW ........................................................................... 29 3.2.1 Thit b o (Virtual Instruments - VIs) ..................................................... 29 3.2.2 Mi trng LabVIEW .............................................................................. 32 3.2.3 Cc hm thng dng trong LabVIEW ...................................................... 37 CHNG 4: M HNH THIT K V KT QU .............................................. 44 GVHD : ThS. L Th Vn AnhSVTH: Lu Thanh Cng ThS.Nguyn Th Hng YnV Vn Cng Phm Th 4.1 Thit k phn cng .......................................................................................... 44 4.1.1 Khi iu khin ......................................................................................... 45 4.1.2 Khi ngun ............................................................................................... 51 4.1.3 Khi bn phm .......................................................................................... 53 4.1.4 Khi hin th (LCD) .................................................................................. 54 4.1.5 Khi Encorder ........................................................................................... 56 4.1.6 Khi truyn thng ni tip RS232 ............................................................ 57 4.2 Thit k phn mm .......................................................................................... 63 4.2.1 Chng trnh trn vi iu khin ................................................................ 63 4.2.2 Chng trnh trn LabVIEW .................................................................... 68 4.3 Kt qu thc nghim ....................................................................................... 70 4.3.1 Kt qu thc nghim b iu khin PI ..................................................... 70 4.3.2 Kt qu thc nghim b iu khin PID .................................................. 71 CHNG 5: KT LUN V HNG PHT TRIN ......................................... 73 5.1 Kt lun ........................................................................................................... 73 5.2 Hng pht trin ............................................................................................. 73 TI LIU THAM KHO ........................................................................................ 74 GVHD : ThS. L Th Vn AnhSVTH: Lu Thanh Cng ThS.Nguyn Th Hng YnV Vn Cng Phm Th DANH MC CC BNG, S , HNH Tn bngTrang Bng 2.1: Gi tr thc nghim xc nh hm truyn17 Bng 2.2: Xc nh cc thng s theo phng php Ziegler-Nichols th nht25 Bng 2.3: Xc nh cc thng s theo phng php Ziegler-Nichols th hai25 Bng 2.4: Bng kt qu cc thng s ca ng c26 Bng 2.5: S nh hng ca cc thng s KP, KI, KD ti cht lng27 Bng 3.1: Chc nng ca Tools Palette33 Bng 4.1: c tnh ra ca IC khi u ra 5V52 Bng 4.2: u ra tng ng khi mt phm c nhn54 Bng 4.3:Bng chc nng cc chn ca LCD 16x255 Bng 4.4: Bng chn l tng ng ca IC 74LS15762 Tn hnhTrang Hnh 1.1: Cu to ng c DC1 Hnh 1.2: S nguyn l ca ng c mt chiu kch thch c lp4 Hnh 1.3: S nguyn l ca ng c mt chiu kch thch song song4 Hnh 1.4: S nguyn l ca ng c mt chiu kch thch ni tip5 Hnh 1.5: S nguyn l ca ng c mt chiu kch thch hn hp5 Hnh 1.6: S thay th mch in phn ng ng c mt chiu7 Hnh 1.7: Xc nh phm vi iu chnh8 Hnh 1.8: Phm vi iu chnh tc v mmen9 Hnh 1.9: c tnh iu chnh khi iu chnh t thng ng c10 Hnh 1.10: c tnh iu chnh in tr ph trn mch in phn ng11 Hnh 1.11: iu chnh rng xung PWM12 Hnh 1.12: Dng sng dng v p trn ng c12 Hnh 2.1: S thay th mch in phn ng ng c mt chiu13 Hnh 2.2: S khi tnh tc theo [rad/s]14 Hnh 2.3: S khi tnh tc theo [rpm]15 Hnh 2.4: p ng qu ca khu qun tnh bc nht16 GVHD : ThS. L Th Vn AnhSVTH: Lu Thanh Cng ThS.Nguyn Th Hng YnV Vn Cng Phm Th Hnh 2.5: ng c tnh ng c mt chiu17 Hnh 2.6: S h thng iu khin dng PID18 Hnh 2.7: S khi b iu chnh t l18 Hnh 2.8: S khi b iu chnh tch phn19 Hnh 2.9: S khi ca b iu chnh t l - tch phn19 Hnh 2.10: S khi b iu chnh t l - vi phn20 Hnh 2.11: S khi ca b iu chnh t l - vi tch phn 20 Hnh 2.12: iu khin vi b PID s21 Hnh 2.13: Minh ha ba cch tnh tch phn22 Hnh 2.14: S khi b PID s23 Hnh 2.15: H thng b iu khin23 Hnh 2.16: Xc nh tham s cho m hnh xp x bc nht c tr24 Hnh 2.17: Xc nh h s khuch i ti hn25 Hnh 2.18: Thng s cho b iu khin ng c26 Hnh 3.1: Font Panel30 Hnh 3.2: Block Diagram31 Hnh 3.3: Icon32 Hnh 3.4: Getting started32 Hnh 3.5: Controls Palette33 Hnh 3.6: Tools Palette33 Hnh 3.7: Numeric Controls34 Hnh 3.8: Boolean 35 Hnh 3.9: String & Path35 Hnh 3.10: Graph36 Hnh 3.11: String36 Hnh 3.12: Array37 Hnh 3.13: For Loop38 Hnh 3.14: While Loop38 Hnh 3.15: S khi m t chc nng thanh ghi dch38 Hnh 3.16: Case Structures v Sequence Structures39 GVHD : ThS. L Th Vn AnhSVTH: Lu Thanh Cng ThS.Nguyn Th Hng YnV Vn Cng Phm Th Hnh 3.17: Formula Node40 Hnh 3.18: File I/O40 Hnh 3.19: String Length41 Hnh 3.20: Concatenate Strings41 Hnh 3.21: String Subset41 Hnh 3.22: Match Pattern41 Hnh 3.23: Format Into String42 Hnh 3.24: Giao tip my tnh vi thit b NI qua cng RS23242 Hnh 3.25: Frame truyn theo chun RS23243 Hnh 4.1: S khi44 Hnh 4.2: S nguyn l khi iu khin trung tm45 Hnh 4.3: S chn v hnh nh thc t ca AVR ATmega1645 Hnh 4.4: S cu trc ca AVR ATmega1646 Hnh 4.5: Khi ngun 5V52 Hnh 4.6: Cu trc IC LM257652 Hnh 4.7: Khi bn phm53 Hnh 4.8: S khi v bng u ra tng ng khi mt phm c nhn54 Hnh 4.9: Khi hin th LCD v hnh nh thc t55 Hnh 4.10: Khi x l tn hiu Encorder56 Hnh 4.11: Cu to ca IC 74LS14 v bng trng thi vo / ra56 Hnh 4.12: Cu trc mch chuyn i tn hiu57 Hnh 4.13: Cu to v hnh nh bn ngoi ca vi mch MAX23257 Hnh 4.14: S mch cu H58 Hnh 4.15: Nguyn l hot ng ca mch cu H59 Hnh 4.16 : Cu to v k hiu ca MOSFET knh N v knh P59 Hnh 4.17: S b cch l quang60 Hnh 4.18: Mch kch cu H s dng IC 74LS15761 Hnh 4.19a: Linh kin thc v s cu to chn62 Hnh 4.19b: S nguyn l v bng chn l ca IC 74LS15762 Hnh 4.20: M hnh thc t69 GVHD : ThS. L Th Vn AnhSVTH: Lu Thanh Cng ThS.Nguyn Th Hng YnV Vn Cng Phm Th Hnh 4.21: Giao din ngi dng khi vn tc t l 50 vng/s69 Hnh 4.22: Giao din ngi dng khi vn tc t l 10 vng/s70 Hnh 4.32: Giao din ngi dng khi vn tc t l 55 vng/s70 Hnh 4.24: Giao din ngi dng khi vn tc t l 10 vng/s71 GVHD : ThS. L Th Vn AnhSVTH: Lu Thanh Cng ThS.Nguyn Th Hng YnV Vn Cng Phm Th K HIU CC CM T VIT TT DC : Direct current (Mt chiu). PID: Proportional Integral Derivative (T l vi tch phn). LabVIEW: Laboratory Virtual Instrument Electronic Workbench. NI: National Instruments. VIs: Virtual Instruments (Thit b o) . PC: Personal Computer (My tnh). UART: UniversalAsynchronous serial Reveiver and Transmiter (B truyn nhn ni tip khng ng b). ALU: Arithmetic and Logic Unit (n v logic v s hc). PWM: Pulse width modulation (iu chnh rng xung). ADC: Analog - to digital Converter (B chuyn i tng t s). LCD: Liquid Crystal Display (Mn hnh tinh th lng). MCU: Micro Control Unit (B vi iu khin). 1 GVHD : ThS. L Th Vn AnhSVTH: Lu Thanh Cng ThS.Nguyn Th Hng YnV Vn Cng Phm Th CHNG 1: TNG QUAN V NG C IN MT CHIU 1.1 Cu to, phn loi v nguyn l lm vic ca ng c mt chiu 1.1.1 Cu to ng c mt chiu Cutocangcinmtchiugmhaiphnchnh:phntnh(stato)v phn quay (rto). Hnh 1.1: Cu to ng c DC Phn tnh (stato) Phn tnh cn c gi l phn cm gm cc t chnh, cc t ph, gng t, np my v chi in. Cc t chnh Cctchnhlbphnsinhrattrng,gmclistcctvdyqun kchtlngngoilistcct.Lithpkthutlmbngcclthpkthut in hay thp cacbon dy 0.5 n 1mm c p li v tn cht. Trong ng c nh cthdngthpcckhi.Cctcgnchtvovmybngbulng.Dy qun kch t c lm bng ng cch in, c qun thnh tng cun, mi cun dy u c bc cch in thnh mt khi v tm sn cch in trc khi t trn cc cc t. Cc cundykch t t trn cc cc t chnh cni tip nhau sao cho khi c dng in chy qua chng th hnh thnh cc cc t tri du xen k. 2 GVHD : ThS. L Th Vn AnhSVTH: Lu Thanh Cng ThS.Nguyn Th Hng YnV Vn Cng Phm Th Cc t ph Cc t ph c t gia cc cc t chnh v dng ci thin i chiu. Li thp thng lm bng thp khi, trn thn cc t c t dy qun m cu to ging nh dy qun cc t chnh. Cc t ph c gn vo v my nh nhng bu lng. Gng t Gng t lm mch t ni lin cc cc t, ng thi lm v my. Trong ng c cngsutlngngtlmbngthpc.Trongngccngsutnhvva thng dng thp tm cun li v hn. C khi trong ng c nh dng gang lm v my. C cu chi than Ccuchithangmcchithanttronghpchithanvnhmtxotcht ln c gp. Hp chi than c c nh trn gi chi than v cch in vi gi. Gi chi than c th quay c iu chnh v tr chi than cho ng ch. Sau khi iu chnh xong th dng vt c nh cht li. Chi than lm bng than hay graphit, i khi c trn thm bng bt ng tng dnin. Chi than c nhim v a dng in t phn ng ra ngoi hoc ngc li. Np my Np my bo v my khi b nhng vt ngoi ri vo lm h hng dy qun vmboantonchongikhichmvoin.Trongccngccngsut nhvva,npmycnctcdnglmgibi.Trongtrnghpnynp my thng lm bng gang.Phn quay (rto) Phnquaycncgilphnnggmlithpphnng,dyqunphn ng, c gp.Li thp phn ng Li thp rto dng dn t, thng lm bng cc l thp k thut in (thp hp kim silic) dy 0.5mm, b mt c ph sn cch in ri ghp li gim tn hao do dng in xoy gy nn. Trn l thp c dp hnh dng rnh sau khi ghp li 3 GVHD : ThS. L Th Vn AnhSVTH: Lu Thanh Cng ThS.Nguyn Th Hng YnV Vn Cng Phm Th th t dy qun vo. Trong nhng ng c c trung bnh tr ln, ngi ta cn dp nhnglthnggikhiplithnhlistcthtocnhnglthnggi dc trc. Trong ng c hi ln th li st c chia thnh tng on nh, gia cc on yc mt khe h gi l khe thng gi ngang trc.Khing c lm vic, gi thi qua cc khe lm ngui dy qun v li st. Trong nhngng c nh, li st phn ng c p trc tip vo trc. Trongng c ln, gia trc v li st c tgirto.Dnggirtocthtitkimthpkthutinvgimnhtrng lng rto. Dy qun phn ng Dyqunphnnglphnsinhrascinngcmngvcdngin chy qua. Dy qun phn ng lm bng ng c bc cch in, tit din hnh trn (trongngccngsutnh)hayhnhchnht(trongngccngsutln), cttrongccrnhcalithpmtscthvccchincnthn vi rnh. trnh khi quay b vung ra do lc ly tm, ming rnh c dng nm cht hoc phi ai cht dy qun. Nm c th bng tre, g hay baklit. C gp C gp (cn gi l vnh gp hay vnh i chiu) dng chnh lu dng in xoaychiutrongdyqunphnngthnhdnginmtchiuarangoi.C gp gm nhiu phinng c ui n ghpli thnh hnh tr trn, gia cc phin ng c cch in vi nhau bng cc tm mica dy 0.4 n 1.2mm. Hai u tr trn dng hai vnh p hnh ch V p cht li. Gia vnh p v phin gp cng c cch in bng cc tm mica. ui vnh gp nh cao ln mt t hn cc u dy ca cc phn t dy qun vo cc phin gp c d dng. Ngoi ra, ng c in mt chiu cn c cc b phn khc nh cnh qut v trc my. Cnh qut dng qut gi lm mt ng c. ng c in mt chiu thng ch to theo kiu bo v, haiunpmyclthnggi.Cnhqutlptrntrcmy.Khimyquay, cnh qut ht gi t ngoi vo my. Gi i qua vnh gp, cc t, li st v dy qun qua qut gi ra ngoi lm ngui ng c. Trc my lm bng thp cacbon tt. Trn trc my lp li st phn ng, vnh gp, cnh qut. 4 GVHD : ThS. L Th Vn AnhSVTH: Lu Thanh Cng ThS.Nguyn Th Hng YnV Vn Cng Phm Th 1.1.2 Phn loi ng c mt chiu ng c in mt chiu c phn thnh cc loi nh sau: ng c mt chiu kch thch c lp Baogmngckchthchbngnamchmvnhcuvngckchthch in t. tU Hnh 1.2: S nguyn l ca ng c mt chiu kch thch c lp = I ng c mt chiu kch thch song song C dy qun kch thch c ni song song vi dy qun phn ng c th t sinh ra dng in kch thch cn thit m khng cn ngun in bn ngoi. tU Hnh 1.3: S nguyn l ca ng c mt chiu kch thch song song I = + ng c mt chiu kch thch ni tip C dy qun kch thch ni tip vi dy qun phn ng. 5 GVHD : ThS. L Th Vn AnhSVTH: Lu Thanh Cng ThS.Nguyn Th Hng YnV Vn Cng Phm Th tU Hnh 1.4: S nguyn l ca ng c mt chiu kch thch ni tip I = =ng c mt chiu kch thch hn hp tU Hnh 1.5: S nguyn l ca ng c mt chiu kch thch hn hp C hai dy qun kch thch: ni tip v song song. I = + 1.1.3 Nguyn l lm vic ca ng c mt chiu Khi t ln dy qun kch t mt in p kch t uk no th trong dy qun kch t s c dng in ik dn n mch t ca my s c t thng . Tip t mt gi tr in p U ln mch phn ng th trong dy qun phn ng c dng in I chy qua. Tng tc gia dng in phn ng v t thng kch t to thnh mmen in t. Gi tr mmen in t: 6 GVHD : ThS. L Th Vn AnhSVTH: Lu Thanh Cng ThS.Nguyn Th Hng YnV Vn Cng Phm Th . .2 .pNM I k Ia | |t= = Trong : p: S i cc ca ng c. n: S thanh dn phn ng di mt cc t. a: S mch nhnh song song ca dy qun phn ng. k: H s kt cu ca my. Mmen in t ko cho phn ng quay quanh trc. Cc dy qun phn ng qut qua t thng v trong cc dy qun ny cm ng sc in ng. . .2 . |e |et= =pNE ka Trong :l tc gc ca rto. e|=. U I Rk Trong :l in tr mch phn ng ca ng c.1.2 Phm vi ng dng ca ng c mt chiu 1.2.1 u imng c mt chiu c:-Mmen m my ln. -Kh nng iu chnh tc bng phng. -Phm vi iu chnh rng, d iu chnh. -Tit kim in nng. -Tui th ln. 1.2.2 Nhc im -Gi thnh t. -Cng sut khng cao. 7 GVHD : ThS. L Th Vn AnhSVTH: Lu Thanh Cng ThS.Nguyn Th Hng YnV Vn Cng Phm Th 1.2.3 Phm vi ng dng ngcinmtchiucsdngtrongccmycngnghipcyucu cao v iu chnh tc nh cn thp, hm m, giao thng vn ti...v c tm quan trng nht nh trong sn xut. 1.3 Cc phng php iu chnh tc ng c mt chiu 1.3.1 Phng php iu chnh in p phn ng S :U fR R EI Hnh 1.6: S thay th mch in phn ng ng c mt chiu Phng trnh cn bng p: = +(+) Do = k.nn= k. + (+) e| |+= ( ). .fI R RUk k Do M = k. nn.MIk|= ( )e||+= 2( )...fR RUMkk e e|= 0( )dkMUVtthngcangccgikhnginncngctnhccng khng i, cn tc khng ti l tng th ty thuc vo gi tr in p iu khin Uk ca h thng. Xc nh di iu chnh tc : 8 GVHD : ThS. L Th Vn AnhSVTH: Lu Thanh Cng ThS.Nguyn Th Hng YnV Vn Cng Phm Th x maminDee= Khi mmen ti l nh mc th cc gi tr ln nht v nh nht ca tc l: x 0 x ma maMe e|= 0 min minMe e|= tha mn kh nng qu ti th c tnh thp nht ca di iu chnh phi c mmen ngn mch l: = =.Trong :l h s qu ti v mmen. V h c tnh c l cc ng thng song song nhau, nn theo nh ngha v cng c tnh c ta c th vit nh sau: 1( ) ( 1) e| |= = dmmin nmmin dm MMM M K00.11( 1)e |e|| = = dm maxmaxdmdmMMMMDMKK Hnh 1.7: Xc nh phm vi iu chnh 9 GVHD : ThS. L Th Vn AnhSVTH: Lu Thanh Cng ThS.Nguyn Th Hng YnV Vn Cng Phm Th Vi mt c cu my c th th cc gi tr, Mm, KM l xc nh, v vy phmviiuchnhDphthuctuyntnhvogitrcacng.Khiiu chnh in p phn ng ng c bng cc thit b ngun iu chnh th in tr tng mch phn ng gp khong hai ln in tr phn ng ng c. Do : .| |/10 V th vi ti c c tnh mmen khng i th gi tr phm vi iu chnh tc cngkhngvtqu10.Trongsutqutrnhiuchnhinpphnngtht thng kch t c gi nguyn, do mmen ti cho php ca h s l khng i: = K. .

= Mm Phmviiuchnhtcvmmennmtronghnhchnhtbaobicc ngthng= ,M=vcctrcta.Tnhaonnglngchnhl tn hao trong mch phn ng nu b qua cc tn hao khng i trong h. Hnh 1.8: Phm vi iu chnh tc v mmen Vy iu chnh tc ng c bng cch thay i in p phn ng l rt thch hp trong trng hp mmen ti l hng s trong ton di iu chnh. 1.3.2 Phng php iu chnh t thng iuchnhtthngkchthchcangcinmtchiuliuchnh mmenintcangcM=K vscinngquaycangc =K .Mchkchtcangclmchphituynnnhiuchnht thng cng l phi tuyn. 10 GVHD : ThS. L Th Vn AnhSVTH: Lu Thanh Cng ThS.Nguyn Th Hng YnV Vn Cng Phm Th kk kb ke dir r dt|e = ++ Trong :: in tr dy qun kch thch. : in tr ca ngun in p kch thch. : s vng dy ca dy qun kch thch. Trong ch xc lp: ||;kk kb kei f ir r| = =+ Khi iu chnh t thng th in p phn ng c gi nguyn bng gi tr nh mc, do c tnh c thp nht trong vng iu chnht thng chnh l c tnh c in p phn ng nh mc, t thng nh mc v c gi l c tnh c bn. Tc ln nht ca di iu chnh t thng b hn ch bi kh nng chuyn mch ca c gp in. Khi gim t thng tng tc quay ca ng c th ng thi iukinchuynmchcacgpcngbxui,vvymboiukin chuynmchbnhthngthphigimdnginphnngchophp,ktqul mmen cho php trn trc ng c cng gim rt nhanh. Khi gi nguyn dng in phn ng th cng c tnh c cng gim rt nhanh khi gim t thng kch thch. ( )2KR|| = Hnh 1.9: c tnh iu chnh khi iu chnh t thng ng c 11 GVHD : ThS. L Th Vn AnhSVTH: Lu Thanh Cng ThS.Nguyn Th Hng YnV Vn Cng Phm Th Do iu chnh tc bng cchgim t thng nn i vi cc ng cm t thng nh mc nm ch tip gip gia vng tuyn tnh v vng bo ha ca c tnh t ha th c th coi vic iu chnh l tuyn tnh v hng s C ph thuc vo thng s kt cu ca my in. .k kb kCCi er r| = =+ 1.3.3 Phng php iu chnh in tr ph Rf trn mch phn ng c im ca phng php: - in tr mch in phn ng cng tng, dc c tnh c cng ln, c tnh c cng mm v n nh tc cng km, sai s tc cng ln. - Phng php ch cho php iu chnh thay i tc v pha gim (do ch c th tng thm in tr). - Tn hao cng sut di dng nhit in tr ln. - Di iu chnh ph thuc vo mmen ti. Ti cng nh th di iu chnh cng nh. 3 2 1 f f fR R R > >0fR =1 fR2 fR3 fRn0n(dmM I )dm( M I )0 Hnh 1.10: c tnh iu chnh in tr ph trn mch in phn ng Trong ti ny s dng ng c mt chiu kch t bng nam chm vnh cu, tthngkhngivkhthayiintrphmchinphnngnnchn phng php iu chnh tc ng c bng cch thay i in p mch in phn 12 GVHD : ThS. L Th Vn AnhSVTH: Lu Thanh Cng ThS.Nguyn Th Hng YnV Vn Cng Phm Th ng. Mt trong nhng phng php thay i in p mch in phn ng l iu chnh rng xung (PWM). Hnh 1.11: iu chnh rng xung PWM Phng php iu chnh rng xung gi tn s khng i nn iu chnh rng xung thay i in p trung bnh t ln ng c. in p trung bnh: =ondk inTU UT Doctnhcmkhngcangc,dngquangcldnglintcnn dng sng dng v p ca ng c nh sau: dkUItt Hnh 1.12: Dng sng dng v p trn ng c 13 GVHD : ThS. L Th Vn AnhSVTH: Lu Thanh Cng ThS.Nguyn Th Hng YnV Vn Cng Phm Th CHNG 2: THIT K B IU KHIN PID CHO NG C IN MT CHIU 2.1 M hnh ha ng c mt chiu S mch in phn ng:UuRu EIuuLu Hnh 2.1: S thay th mch in phn ng ng c mt chiu Vi: : in p phn ng (V). R: in tr phn ng ( ). : Sc in ng phn ng (V). : Mmen cn t l vi h s ma st v tc (rad/s). ( ) T t : Mmen cn thun. b: H s ma st (rad/s). J: Mmen qun tnh ca ng c v ti. : Hng s mmen (Nm/A). : Hng s sc in ng (Vs/rad). = = K: hng s ng c. p dng lut Kirchoff vo s trn ta c cc phng trnh vi phn sau: ( )( ) . ( )( ) . ( ). . ( ). ( )( )( ) . ( )( ) . . ( ) . ( ) ( )Tdi tU t Ri L E tdtT t k i t K i tk K K Nm Ad tT t b t JdtU t k t K t Vs rad||ee| e e= + += == = == =

Bin i Laplace ta c: 14 GVHD : ThS. L Th Vn AnhSVTH: Lu Thanh Cng ThS.Nguyn Th Hng YnV Vn Cng Phm Th () . () . . () ()() . ()() . () ()() . ()U s RI s L sI s E sT s K I sT s b s J sE s K se ee= + + == += () 1() () .()()()() 1() .I sU s E s R L sT sKI sEKssT s b J see= += ==+ Ta c s khi tng ng vi cc phng trnh trn: 1b Js +U( ) sI1R L s +( ) s( ) s eKK( ) E s( ) T s Hnh 2.2: S khi tnh tc theo [rad/s] Hm truyn t: ( )( )( ) 2 2 .( . )().( . )1.( . )KR L b J sKW sK R L b J s KR L b J s+ += =+ + +++ + =| | | |+ + + ||\ .\ .2 .W()1 . 1.KRbsL J Ks sR b Rb t: LTR=: Hng s thi gian ca mch in phn ng. 15 GVHD : ThS. L Th Vn AnhSVTH: Lu Thanh Cng ThS.Nguyn Th Hng YnV Vn Cng Phm Th mJTb= : Hng s thi gian phn c. Do mT T