1.4 Cac tinh toan CO' ban
1.4.6 Df) meo d;mg hai t6ng (Total Harmonic Distortion-THO)
D<) meo d~ng hai t6ng duqc djnh nghia la can b~c hai ty s6 giua t6ng cac thanh phAn khong CO' ban va thanh phAn CO' ban. Mvc dich xac djnh chi s6 THD nhfim bi€t ch§.t lu(Jilg cua m<)t d~ng song la nhu th€ nao so v6-i song Sin tAn s6 CO' ban, gia tri THO cang 16-n la d~ng song d6 cang x§.u so v6-i song Sin chu~n 50Hz va nguqc l~i.
Lf~,rms
THD= n,,el 12 l,rms
(1.43)
(1.44)
M6i quan h~ gifra d<) meo d~ng hai t6ng va h~ s6 meo d~ng nhtr a cong thuc du&i day:
DF=
l+(THD/ (1.45)
1.5 Hll'ong dfin s~ d1}n~ phft,n m~_m PSIM, , Hi~n nay c6 rat nhieu phan mem c6 the mo phong di~n tu cong suat
r~t t6t nhu: Matlab, Psim, Spice, Pspice, and Capture. Trong s6 d6 thi PSIM duqc biSt dSn nhu la m<)t phftn m~m chuyen dung cho di~n tu cong
su~t va truy~n d<)ng di~n. Ph.in m~m nay ngoai mo phong ly thuySt con c6 h6 trq cho phftn thvc hi~n thvc nghi~m thong qua giao tiSp v&i card DSP F28335 cua hang TI r~t t6t. Du&i day la ca ban sfr di,mg ph.in m~m PSIM.
Sau khi cai d~t thanh cong ph.in m~m PSIM thi tren man hinh may tinh se c6 bi6u tuqng .. Im::::, d6 su di,mg phftn m~m ta click double vao bi6u tuqng tren se hi~n ra man hinh nhu a hinh l .15.
, f!J PSIM ; :,:; )~!~:[~~~g:rt~~:~1~~~g~~~~~~~;r~~~~~~r+:~~€Ơ1ắ:~~~=~~~~~"ig~~~~5~i~i-~~~~1~;~:?;:~~~::~~;=;~x~;~~~~~~~:~~~;~~>::;::: ~~- ~1~-..itii
~~,-,, .. ~~ ~ ~~~~-:-~."":-~-~~ .. ,,¥()~ ...... H~r.t1~--~~-~ ~ ,,,.,,,,. -.-_ .,.,,, ... _,, _______ .- , ... , .... ,.,, ... ... , ... ,. _,, ... .
Hinh I .15 Man hinh cit a Ps im
Chu y: Nen cai d~t Psim v&i phien ban m&i nh~t, vi phien ban m&i nh~t se duqc h6 trq nhi~u cht'.rc nang, nhi~u module chuyen dung han. Psim su di.mg trong giao trinh nay la Psim 9.03 ban 64bit.
0~ bit d§.u mo ph6ng m9t m?ch di~n tu cong sudt ta vao File-►new ho~c bdm chu9t trai vao bi~u tuqng --~J se hi~n ra man hinh d~ SO?n thao mo
hong m(>t m?Ch di~n tfr cong sudt nhu a hinh 1.16.
la] PSIM. luntitled_lJ ,-. :,::x_:: 2~:::ã.::L+;:: J_:~:~1L'.:t.:~~0}~i'~t~~~~x.~~~~~:~::;:_:~GE. i~ ;~'đ~/WW
_
If.ii "-~lie E~~ "\J~ Su~i_rc;:urt Ê1~-~-~-U ___ Simul~~---()P~~ns --~-il_~_i,~ ... ~i-~dll'\'t ___ H~~, , _ _ _ _ .... ,,_ .• :,,~,_lf 6 rãã;c: -
3 D/~/liil/.>I ) I /Ii"/ã I .JiJI -d::J ;,/1.'I' • I ~ ~ .A./.R/.ằ/Di rJ°!/11/•,j".il'l:'i ~ :d.
Hinh 1.16 Man hinh chinh cua Psim
Trong hinh 1.16 chung ta nh~n thdy a phia du6i bao g6m cac ph§.n tu
CO' . ban thm'mg dung nhdt khi mo ph6ng di~n tu cong sudt nhu sau: ~
+ l".'l'"':l~,_l_,._l..,.IJ~IJ<tl~l~l lllfl*I (\')l'âl!I lt';li~I ~l-$1'$!'$1ã01 :o.-l=-t-1 .. 0Jđl!l~li>_l1iEIL~l<lj!,l'!li--.. -- .
. I ,?
"'e•ã-•-rããã~ "''>'.::c"_-.,,,ã.~-,,,--,~ã,c;-'"'-~'-•--'-- ,..,.--..,,,, .... ,,"-•ã .. ,. '~ -~ -ã-ã~=ãã"ãã• ,ã •-;"-~ -.-,.~-. > ,ã - ~ - - - ' - • -_, •• ,
Muon biet phan tu d6 la gi thi chi can re chu(>t trai den phan tu d6 thi
ph§.n m~m se hi~n ten cua ph§.n tu d6 ngay a g6c du6i cung ben trai. Khi da chc;m duqc ph§.n tu dn thi~t thi ta chi dn click chu(>t trai m(>t 1§.n vao ph§.n tu d6 (chi click chu khong gift chu9t) va re chuQt d~n nai dn d~t va click chu9t trai, n~u mufm d~t nhi~u ph~n tu gi6ng nhau tren m(>t m?ch thi ta chi click chu9t trai d~n nhung vi tri d6, mu6n xoay ph~n tu thi click chu9t phai, mu6n k~t thuc lip d~t m9t ph~n tu thi nhdn nut Esc.
Tren thanh cong C\.I phia tren c6 cac chuc nang CO' ban thuc'mg dung nhu sau:
l1ffj]F,~. Ed~~ ~ T ~f~,:;,, ~1~ 1 ~ 1 :0ã: ,:r~: , ~j~j;;r~ ;;,o ~ ,Q/Pl~IDI rif11i:ã1~;1~ ~ :d
The Elements chua tdt ca cac phftn tu dn cho mo ph6ng, chuc nang nay thm'mg dung khi ta dn tim cac ph§.n tfr khong c6 a thanh cong C\.I ben du6i nhu hinh 1.17.
l';ã : ~2 ;;~ ... :-~ \~ ãã•~:_~ =-~~ ;~.h;):;:;~:~::\~c.ã~• - -
~ -~!i!J~ p_... m1<...:11tc1, •""'°'
'""'"" wikt\ft
0.,... t,H~
_ _ .. l _ _._,... • llC
tlwrNMaoo.a IIIW~
~ & M , , , g , Sah,,-'"lndu<lor
Co~J~du<to,(l) Coup\otdlMLlrt&iih (,:,,i,pledl~0<i41 (~k>Ouct-ằ{5.l C~illdt.lcl:•*l ... .,.. ... u,,_nl{j,) , . . . _ l - • • l!<'I ,_.._,fie,,,w,,tnl(l•J
,.._,...,.n,ro-.~
Hinh 1.17 Thanh cong qi v&i the Elements
Chuc nang Simulate: sau khi lip m~ch mo phong xong, chung ta phai cai d~t cac thong s6 mo phong. cac thong s6 mo phong duqc cai d~t nhu sau:
Ta b~m vao Simulation Control se hi~n !en bi6u tuqng d~ cai d~t thai gian mo phong. Chuc nang nay thuang duqc sir di,mg sau khi da lip xong m~ch mo phong. Click double vao bi~u tuqng ' n6 se hi~n !en bang di~u khi~n mo phong nhu & hinh 1.18.
- ~.111:ã 'L ...
.:II D!i;;l;!lill•I J', IQ
Run Simulation Uncel Simulation Pause Stmulation Rest:Mt SimuL•bon Simulate Next Time Step Rur,Slt,MEW
Gena• Netldt Fa VtewNetfistFNf!
SoowWoming Anang,,SIJNl(Nocies Generate Code Runtime Graphs
F8 Ct,ViMt-18
Al-fll
.,..,,.1~,~~, .... ,-,J.;t,1")1:0101 ~ ~ m <$1ã$1ãE,1-.$1•Â,1 ~ 0 1đ1~1~1t+~r&1,;t1'1i11 !!!I~ Ê
Hinh 1.18 Chuc nang dieu khii~ mo phong
Ti~p theo ta ch9n Simulation Control n6 se hi~n ra bang thong s6 nhu &
hinh 1.19.
Tilnesllep I JE-00s
Tola tine lo,oi ir Freerwi
Pmtliffle Io
Printsfl!p Ii
Load flag lo 3
Save flag lo 3
Hardwire T.wget !None 31
Hinh 1. 19 Cac thong s6 aiJu khidn mo phong Trong d6:
- Time step: thai gian bu6c;
- Total time: t6ng thai gian mo phong (thai gian tren t11,1c X);
- Print time: thai gian in xu§.t ra d6 thi, thai gian nay phai nho hon t6ng thai gian.
Vi d1.1 ta d~t Total time la 0, ls va Print time la Os thi c6 nghia la d6 thi mo phong duqc xuftt ra trong khoang tir Os d~n 0, 1 s. Con n~u ta d~t print time la 0,02s thi phfrn m€m chi xuftt ra d6 thi trong khoang tir 0,02s d~n O,ls thoi.
Vi du 1.4
Ta hay mo phong m(H m~ch chinh luu hinh tia ba pha c6 di€u khi~n dung SCR nhu a hinh 1.20
E L R
Hinh 1.20 Mt;tch chinh liru tia ba pha c6 aiJu khidn
Sa d6 m6 phong Psim duqc xay dl,fllg nhu 6 hinh 1.21:
• l••Hã+'H/!l:'!lllllĐI -W ~ - ~ tl't-1 <lll'!J!tl2~1!!1 Al:tL!l bMĐiil'Aii•i!i!!\Ơ!ƠĐ@61iii/l,li i ii fi \& II !!~iii,ã~
Hinh 1.21 Sa ad m6 ph6ng Psim cho vi dl:l 1.4
Trong so d6 m6 phong tren thi chi c6 kh6i t{lo xung kich la kh6ng c6 6 m~t tru&c cua man hinh Psim. Do v~y ta vao Elements r6i tim d~n Alpha Controller d€ tim nhu 6 hinh 1.22.
j
Hinh 1.22 Cach lap kh6i tgo xung kich
Khi click vao bi€u tuqng Alpha Controller ta se th~y h(>p thong tin nhu 6 hinh 1.23.
27
.. ..... . f .. ... ..... ...... .... .
: : {i''~ :
Delay ande. ~ a:inlrall!I'
llspay
...
, A_CTRL_5 _ _ _ _ _ r
lso r .:J
....
, 1 - - - - - r .:.1
Hinh 1.23 Thong s6 g6c kich aiJu khiin
Trong hinh 1.23 ta chu y d€n thong tin Pulse Width: day la de) r<)ng xung kich, gia _tri nay thm'mg khon& duqc, 16n, n€u gia ,tri nay 1?°11 thi se xay ra trimg dan trong qua trinh dieu khien. Gia trj hien thi bieu thi de) r<)ng xung d6 la bao nhieu de).
Sau khi cai d~t xong tfrt ca cac thong s6 trong sa d6 mo ph6ng, chung ta
~ , •;: ~ 11 ,:. A C ~ '> A '> ~ • A
barn vao b1eu tuqng ~ de ch1;1y mo phong. Ket qua mo phong se htyn Jen tfrt ca cac d,;mg song theo ten chung ta d~t trong sa d6 mo ph6ng nhu 6 hinh 1.24. Cac ten nay chung ta c6 th~ An khong dn hi~n thi tren man hinh.
~ ~
ããã.1 ~
.~□ I~
l,j•.
3 "'v (\ {'-'i, V \r f' _, .:,. ~ • I ,. P S IN(> '.~k'J'.:~ :~ , l ! t ;;,:t,f\1i~ ~ ~j~\;J~~!P.'!!'~!!'.~ ~~'1~~'l!~~ !"ti'!!L'.'1'1~ir"':~~~-t:rr,:~
Hinh 1.24 Cac ket qua mo phong cua vi dl;l 1.4
, ' I X ,
De xem cac gia tri trung binh ta barn vao _. - , de xem tri hi~u di,mg
I
ta b§.m vao nns , gia tri h~ s6 cong su§.t l.~-, gia tri P , gia tri _:_,
™D . ,
gia tri ---... 6 thanh cong C\l ben du6i. Chang h~n ta muon xem gia tri
' I X
trung binh cua cac d~ng song tren hinh 1.24 ta barn vao nut- ---, ta duqc k~t qua hiSn thi nhu o bang 1.1.
Bang 1.1 Cac g_{q. trf trun AverageV ã
•ã rme From Tme To uA i 1 uB
2.9000000e+000
3.0000000e+OOO -1 .8694536e-011 -1 . 9050655e--002
UC 1 .9050655e--002
~~--- -- - - - --- -- -,1ã~;.;;~~~;- ---
~ : ~: ~ ~ :: : :: ~: : ~: ~::: I~- ~i~~: :::: _ :
£1"~1 __________________ J1.:?~?~~ ______ _
uT1 -1.5723162e+002
Tren bang l. 1 cac ten ham uA, uB, uC, ... la do chung ta dl)t trong luc xay dvng SO' d6 mo ph6ng.
Chu y each d9c: gia tri e-00 l tuc la l 0-1, e-002 la 10-2, e+OO 1 la IO 1,
e+002 la 102, e+OOO la 1 o0.
Vi dv: gia tri tri trung binh di~n ap tren tai Ud hiSn thi la l .5723 l 73e+002 thi ta se d9c la 157,23 I 73V.
Tren bang 1.1 d.n chu y d~n thai gian do d~c la khoang bao nhieu chu ky.
(vi dv tu bang 1.1 la thai gian tu 2.9s d~n 3.0s, tuc la cac thong s6 trong 0, 1 s c6 nghfa la 5 chu ky. Tuy nhien cac cong thuc thuang tinh cho m9t chu ky, day la nguyen nhan lam cho dap s6 gifra tinh toan va mo ph6ng la hay sai l~ch nhau m9t ty).
DS xem d~ng song nao ta click vao biSu tuqng = /ph~n m~m se xu§.t hi~n toan b9 cac d~ng song da dl)t ten trong so d6 mo ph6ng (hay con g9i la thu9c tinh cua cac thong s6) nhu 6 hinh 1 .25.
29
~.ã,ã
~ . Select Cur\les l c . urve.slScreenl
~ Variables available Variables for cisplay
id ill tA
uB Addã>
uC ud
us
uT1 V4 V5
•
OK Cancel
Hinh 1.25 Thu9c tinh cita cac thong so
Mu6n xem d~ng song nao thi ta double click vao d~ng song do ho~c nh:ln click m()t cai r6i nh:ln Add. Ta cung co thS thtJC hi~n cac phep tinh v6i cac tin hi~u b~ng each chc;m tin hi~u do r6i b:lm ■ dS dua tin hi~u xu6ng sau do dung cac phep tinh dS tinh toan. Gia Sil ta mu6n thtJC hi~n
• &l!ilJit
V4*V5 ch~ng h~n lv4v5 . Sau khi chc;m xong ta b:lm nut OK la xem duc_yc d~ng song.
Tren d~ng song hiSn thi chung ta co th€ thvc hi~n cac thao tac don gian nhu: phong to, thu nho, xem d~ng song tu thai gian bao nhieu d~n thai gian bao nhieu, thtJc hi~n d~m net cac duang cong hi~n thi, thay d6i mau sic hi~n thi, hi~n thi co lu6i hay khong co lu6i ...
Khi chc;m the Curves se xu:lt hi~n man hinh nhu 6 hinh 1.26, man hinh nay chua cac thong tin nhu la Label, mau cua tung d~ng song, muc d() d~m nh~t va d~ng bi€u tuQ11g t~o nen d~ng song do.
N~u ta chc.m the Screen thi se xu:lt hi~n man hinh nhu 6 hinh 1.27, man hinh chua cac thong tin v~ man hinh hi~n thi nhu la mau n~n, mau lu6i, ch~ d() in, hi~n lu6i va font chfr hi€n thi tren d6 thj.
: s eiect Curves Curves ls creen I
Label
Color It : ;_;j
Line thickness [ _ .. 3
Marker symbol .1---3-. ..
OK ] Cancel
Hinh 1.26 Cac thong s6 cua Curves
. select Curves I t~rves Screen I
Foreground color Background color Ii
Grid color
Font ABC
[J [J
[ j r Hidegrid
i ... ) r Hide aMis te~t
r -- . OK '
Hinh 1.27 Cac thong so cita Screen
Cancel
M<)t uu di€m cua ph~n m~m Psim nfra la sau khi cai d~t thanh c6ng thi chung ta c6 th€ xem duqc r~t nhi~u cac vi dl,l m~u hiiu ich c6 s~n trong ph~n m~m b~ng each vao 6 dia cai d~t ph~n m~m -chc;m program file -powersim-Psim 9.03-examples-.... Ho~c la ta c6 th€ vao Help -Index d~ xem hu6ng d~n ti mi cua chinh Psim nhu a hinh 1.28.
, ~::ã-~ ~ l;;~ ~:J~ ;J-~ :i~::::~~2::t:lilJ~!-~li~:::;0;;;::;:J;:!~ltf~Cii1f~\;::;Li~~~ ~~ill~~~~~1_~iffir~::;'.;"7Z~~E:~:;:ã::::~:2 __ : 1.' , -=
~ . ã•ã~ ã +r..:,;.;,.:1"i-ã;;1::r;r;::, -- 1,,,ai~.ilif~r -- ããã ãããã ã----~-
'•",...,.,. __
r,j..,.~ , ~::<:.-.::. •ãã: .. j_ .... _..,.. ___ _ .,_lã=ã = =ã--ã~"C-'-ã~- - ~~Lca ___ ,1__01 __ . . . ,~--'
I ~ ,. "'ã _. [!'i
l - - r-,...••--- ---"'--- - -- ---H
lc.---1.,_.1,..<'11,ã- 1 ~ ' °
. J
I ,., ~ ;:,r-E --• PSIM
P'S.M1SINllo...,._.._ ...Ode ... . . . . • b~ f t ô" - :1.1N;11e11S-t
~ ~ I Y l ( M ' I I - - - -w.J'll:n!IJlftlia _ __,_ y { O -f t ~ • PSllil
{~ e.,,i,. , . . . p(M(lit11~ . . . . i - - -i:,,,- , ( !4-.e<l'fOIII--IOl'I""'°'
~ ...
I ' fll IN11 . . . f,l,tc-1PSIM.-.dh-,,,t(ll!lbpll<ll'IJ
. =-==- fhit•tehon-i,,,do,1!,,.""'-'9Wllo.1
lfl =- --;_ --::.._ l l ' l l ~ ! t U W P S I M ~N •1iddo,iopl'-•
I ill ., - r -- l:Jlf',..._.Dl>-..,. . . - N . , f'SM OO--o:.-t:1,1111_,.,C.,,..olut.u,l•t
~ l . . b1Mlt1ito1Ps.l
I
,_m,_,o_mrn
fã~ (111""1)1! !INI--F19IIIHH11"I
., .,r
'lããH-H-!iOl",Jjfiljaj !!UJ ~, ... , ... , i::l!ill ~l'HOj'$j'<l>j t>l!:J <D(Oj'9j'9li>j0j H"l<i>I.
Hinh 1.28 Chuc nang Help trong Psim
Ngoai cac chuc nang ca ban a tren, ph~n m~m Psim con h6 trq m(H ph~n r~t quan tr9ng d€ th\Ic hi~n cac m~ch thvc nghi~m. 06 la Psim k~t nbi duqc v6i card DSP cua hang TI (Texas Instrument) nhu la DSP F28335d€ th\Ic hi~n duqc r~t nhi~u ung dvng nhu 3-phase PWM, 2-phase PWM, A/D converter. .. Xem hinh 1.29.
Control Othi!r Sources Symbols
Eve:nt Cont,ol
SimCoder for Code Generation TI F28335 T .trget ► Tr 3-phase PWM
PE-Pro/F28335 Target ► 11 l-phue PWM t, 1-phase PWM
P£-Expert3Tug@I ► T1 S.ngJePWM(~redwithc.apturt:) General Hardware Target ► T1 Sl;,rt PWM
G., Gk>bal Variable 11 Stop PWM
G Interrupt T1 Trip-Zone
' - - - ' - - - 1 Tt Trip-Zone State Tt A/0 Converter . T1 Oigitallnput
T1 Digital Output T1 Capturll!
t1 Capture State 11 Encoder T1 Encoder State 11 Up/Down Counter Ti DSP Clock
11 Tl F2833S Hardware ConfigurattOn
Hinh 1.29 Psim v6ãi Tl F28335
N6i chung, phfin m€m nay su dt,mg khong c6 gi la kh6, chung ta chi dn lam vai vi dà la c6 th€ SU' dàng thanh th~o phftn m€m nay r6i. D?C bi~t trong cac chucmg sau, tac gia c6 16ng phfin mo phong Psim vao trong cac vi dà d€ so sanh k~t qua tinh toan va k~t qua mo phong duqc tu phfin m€m Psim. Cac hu6-ng d~n hen tren chi la hu6-ng d~n so- luge thoi, n6 con tuy thu('>c vao mt'.rc d9 pht'.rc t~p va d9 thich thu v6-i phfin m€m cua chinh nguai h9c nfra. Do v~y, n~u sinh vien nao da su dàng thanh th~o Matlab r6i thi cu su dàng Matlab, th~t ra phfin m€m mo phong chilng qua la cong cà thoi, quan tr9ng la ta phai hi€u ly thuy~t thi ta m6-i dung phfin m€m duqc va khi phfin m€m ch~y ra k~t qua thi ta m6-i bi~t k~t qua d6 la dung hay sai.