Nghiên cứu thiết kế và chế tạo máy đo công suất vạn năng ứng dụng thuật toán tương quan

Tuyen tap bao cao khoa hoc Hdi nghi Khoa hgc ky thuat Do ludng toan qudc Ian thfi IV Hd Ndi, 11-2005 I NGHIEN COU THIET KE vA CHE TAO MAY DO CONG SUAT VAN NANG UTNG DUNG THUA T TOAN TUONG QUAN Phgm Thugng Hdn BUi Ddng Thdnh Bd mdn Ky thudt vd Tin hgc Cdng nghiip - DHBK Hd Ndi Tdm tdt: Hiin cd nhiiu phuang phdp di cdng sudt, nhu phuang phdp ca dien, phuang phdp diing cdm bii'n Hall Tuy nhiin cdc phuang phdp ndy gap rdt nhiiu khd khdn cdc ling dung vi cdng sudt ddi hdi dd chinh xdc cao Viic ling dung thudt todn tuang quan de gidi quyet bdi todn cdng sudt dgt chinh xdc cao dd dugc tiin hdnh vd da nhdn dugc cdc kit qud tich cue Trong dd sd dung phdn td xd li PSoC, mdt thi hi chip tiin tii'n de thuc hien thudt todn ndy Abstract: Nowadays, a lot of methods that can measure power Example Mechanics-Electrics method Hall sensor method however, this methods have a lot of difficult when measured result require high accurate Used correlate Algorithms solve measure power problem that can be high accurate carry out and obtained active result This application used PSoC, that is improve CPU performed this algorithms I DAT V ^ DE Hifin trfin thi gidi da ed nhilu cdc phuong phap cdng sudt khdc nhau, cdc phucmg phdp ndy hifin dang tdn tai nhilu nhugc dilm, cd thi xet mdt sd phuong phdp cflng sud't CO ban bifin + Phuong phap co difin boat dflng dua trfin cac co cdu chi thi difin ddng, ddy Id phuong phdp cflng sudt thflng dung va don gian, so dd ciia chfing dugc trinh bdy trfin hinh sau: ^5r b) Hinh So nguyen li eua wattmet didn dflng 406 Trong dd cudn dp b duge mac song song vdi phu tai, cudn ddng a dugc mdc ndi tifi'p vdi phu tai cdn Phuong trinh ddc tinh thang cua Wattmet difin dflng duge bieu difin nhU sau: UI a= DR+R„ dM., ^ da a - Goc quay cua cO cSu chi thi D- Hfi s6 can rifing cua 16 xo — bien thifin tucfng ddi cua ho cam theo g6c 16nh a da Vdi phuong trinh dac tinh ta thdy dfl nhay cua Wattmet difin ddng cd thi xde dinh dugc la: „ dM„ da R,+Rp Ddy chi'nh Id dfl nhay cua Wattmet mflt chilu vd cdch tinh tuong tu ddi vdi Wattmet xoay chilu nhifin dd phai kl din gde Ifich pha giua hai dai lugng "u" va "i" Uu dilm ndi bdt cua loai thifi't bi cdng sudt la bin, tin cdy nhung nhugc dilm Id chfnh xdc khdng cao, chiu sai sd qudn tinh, sai sd su tifiu thu ndng lugng trfin eae cudn ddy + Phuong phdp cdng sudt dung cam bien Hall duge Irinh bay trfin hinh sau: Hinh Wattmet dfing cam bien Hall Cam biln Hall thuc chdt la mflt mang bdn cfia dugc ehl tao dudi dang mdt tdm mdng bdng chd't ban ddn Hai cue ddng ky bifiu la T-T eua cam bien dugc mdc vao ngudn difin mdt chilu hodc xoay chilu nhu hinh ve Hai cue dp duge ky hifiu la X-X Khi ddt vudng gdc vdi bl mat ehuyin ddi mflt tfi trudng thi xudt bifin d hai ddu X-X mflt sfic difin ddng ggi la sfic difin dflng Hall va dugc tinh nhu sau: E, = k,*B*i, Trong dd k^ Id hfi sd md gia tri eua nd phu thude vao vdt lifiu, kich thudc vd hinh dang eua cam bifi'n Ngoai nd edn phu thudc vao nhifit dfl cua mfli trudng xung quanh, gia tri ciaa tfi trudng Dl thfic hifin Wattmet dua trfin cam bifi'n Hall, ta ddc cam bifi'n vao khe hd cua mdt nam chdm difin Ddng di qua cudn hfit L chinh la ddng difin di qua phu tai, edn trfin hai cue T-T se cd ddng difin chay qua ti Ifi vdi difin dp dat lfin phu tai Difin trd phu R dung dl ban ehl ddng Hudng cua tfi trudng duge ehi bdi dudng net dut Khi dd sfic difin ddng Hall dfigc tinh theo bilu thfic sau: E, = k*u*i = k* P 407 Ifu difim nfli bdt cia ±ie't bi cfing sudt ndy la khfing qudn tinh, cdu tao don gian, til cdy nhung nhugc difim la chinh xdc khfing cao Chiu sai sfl su bifin dfing cua nhifit mfii traflng Ro rdng cdc mdy cflng sudt tfin tai nhifiu nhugc diem dac biet Id dfi chi'nh xdc khfing cao, de chiu anh huflng cia nhieu tac dflng len kfit qua phep Ap dung thuat todn tuong quan dfi tifin hanh cfing sudt la mflt huflng moi ky thudt dien Phttong phdp ndy co thfi cho dfi chinh xac y, chttng phu thufic vao so lugng cdc diem ldy mdu phep Ngoai phuang phap tttong quan cho phep loai bfl hodn loan cdc tac dflng cia nhifiu, rdt thich hgp vfli cacttngdung xa vd dfli hoi kfit qua cfl chinh xdc cao Day cung chinh Id de tdi nghien cttu khoa cJp truflng T2002 tai traflng Dai hgc Bach khoa Ha nfli vd da dttgc nghiem thu thdnh cfing II NOI DUNG PHUONG PHAP Gia si cfi hai tin hifiu ttt xa la difin dp va dflng difin U(l) = U sin at i{l) = l,„sin[a>t-\-ip) (1) Khi cfl nhifiu n(t) ta cfl tap hgp u(t) + n(t) vd i(t) -I- n(t) Gia thifit la tin hieu vd nhifiu dfic lap vfli Ta xet ham hfl tucmg quan R-(T) = M{[u(t)-l-n(t)].[i(l + x) + n(l-l-t)]} = M {u(t) i(t -I-1) -l-u(t) n(t -I- T) -I- i(t -n:) n(t) -f n(t) n(t •)• t)) = Rui (t) + Run (T) + Rin (T) -I- Rnn(T) (2) Vi tin hifiu vd nhifiu dfic lap cho nfin cdc ham sfi tuong quan R„„ (x) va R,„(t) dfiu bdng khfing vfii mgi x Cfln x > x„, x,, Id khoang tuomg quan cia nhifiu ngdu nhien n(t) thi Rnn(x) = Vdylakhix>x„,thl R-(t:)^ R-(x)M{u(t)i(t-x)} (3) Thay cdc gid ni u(t) va i(t)fl(1) vdo (3) vd dy trang binh theo mflt chu ky T ta cfi: KM = - \u, sm eo./„ sin[(t>{t + x)(p]rfr (4) Ldytt'chphdn ta cfl , T K,('') = - luj„cos[(z)-l-tf] Vflix = kT(k=l,2 )vax>x„ Taco: ^,(KT) = -f/,,/„cos(p (5) Bdy gifl xfit ham urong quan cia cac tin hieu u(t) vd i(t) rifing re - cing vfli x> x^ ta K.{l) = -Ulc0S(pT «,v(')=-/;coi((>x Vfii x = kTthi: «»,(*r)=UJI = U'^U = 4Rja) RikT)=-il=r " Xet ty sfi: (.6) ->I = ,JR„(k Km (7) —U„,I,„cos(p yJR,,(,kT)R„(kT) (8) = COS(p \uj Nhu vdy giai thuat loan (Algorithm) xet ty sfi gitta cdc hdm hfl tttOng quan va cdn bdc hai ham ttt tugng quan cfl thfi tinh dttgc hfi sfi cfing sudt cos