do an ups chung
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Thit k b nghch lu cho h thng UPS c kh nng kt ni li
SVTH: Nguyn Vn Chung Lp TB-T1-K51 1
MC LC
LI NI U ....................................................................................................... 2
Chng 1: TM HIU V UPS V NG DNG ............................................... 3
1.1 Gii thiu chung v UPS ................................................................................ 3
1.2 Phn loi UPS : ............................................................................................. 4
1.3 ng dng ca UPS trong thc t : .................................................................. 9
Chng 2: TNH TON THIT K ................................................................. 11
2.1 Thut ton to sng sin ................................................................................. 11
2.2 Cc khi mch s dng ................................................................................ 17
2.3 Tnh ton mch lc thng thp ..................................................................... 24
Chng 3: XY DNG KHU IU CHNH IN P ................................ 30
3.1 Nguyn l chung ca khu t ng iu chnh in p : ............................... 30
3.2 Xy dng m hnh ton cho cc khu ca mch nghch lu : ....................... 30
Chng 4. NGHIN CU CC MODULE C BN CA
DSPIC33FJ12MC202 .......................................................................................... 37
4.1 Tng quan v vi iu khin dsPIC33FJ12MC202: ....................................... 37
4.2 Cu trc vi iu khin : ................................................................................ 38
4.3 T chc b nh: ........................................................................................... 40
4.4 Khi qut v cc thanh ghi: .......................................................................... 41
4.5 Gii thiu cc module c bn ....................................................................... 43
Chng 5: TM HIU PHNG PHP HA NG B.............................. 63
5.1. Nhu cu ha ng b vo li ..................................................................... 63
5.2 Cc iu kin ha ng b ........................................................................... 63
5.3 Vng kha pha (Phase Locked Loop - PLL) ................................................. 63
Chng 6: M HNH V KT QU O C ............................................ 73
KT LUN .......................................................................................................... 75
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Thit k b nghch lu cho h thng UPS c kh nng kt ni li
SVTH: Nguyn Vn Chung Lp TB-T1-K51 2
LI NI U
S ra i, pht trin nhanh v ngy cng hon thin ca cc linh kin in t,
c bit l vi x l to ra s thay i su sc v pht trin mnh m trong cc
thit b, h thng thit b in - in t. Nhm m bo tnh lin tc v cht lng
cung cp in cho nhng ti nhy cm m khng ph thuc trng thi h thng
cung cp, phng php duy nht l s dng b ngun d tr lm vic tin cy.
Hn na, hin nay nng lng ngy cng cn kit, nn nhiu ngun nng lng
mi v ang c ch , s dng nhiu hn nh: nng lng mt tri, nng
lng gi,... Cc ngun nng lng c th ni l v tn ny s gip to ra ngun
in nng ln nu c s dng tt, gim ng k gnh nng cho thy in v nhit
in hin nay ang phi gnh vc.
Xut pht t nhu cu thc t trn em quyt nh chn ti nghin cu l:
Thit k b nghch lu cho h thng UPS c kh nng kt ni li.
Em c gng nghin cu v thit k di s hng dn tn tnh ca thy
Hong Anh v thy Nguyn Thnh Khang. Tuy nhin, do s hn ch v nhiu mt
nn chc chc n ny cn nhiu thiu xt. Em rt mong nhn c s gp ca
cc thy c ti ny hon thin hn!
Em xin chn thnh cm n!
Sinh vin thc hin
Nguyn Vn Chung
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Thit k b nghch lu cho h thng UPS c kh nng kt ni li
SVTH: Nguyn Vn Chung Lp TB-T1-K51 3
Chng 1: TM HIU V UPS V NG DNG
1.1 Gii thiu chung v UPS
UPS c vit tt ca cm t ting Anh: Uninterruptible Power Supplier
c hiu nh l h thng ngun cung cp lin tc hay n gin hn l b lu tr
in d phng nhm lm tng tin cy cung cp in cho h thng.
1.1.1 Cu trc chung :
Ngun d phng (Acquy hoc my pht)
Mt b chnh lu
Mch lc cho khu chnh lu
Mch nghch lu
Mch iu khin hot ng cho cc van.
1.1.2 Gii php dng UPS :
iu cn ch trc ht ca nhng s c v hu qu ca n v phng din:
An ton cho ngi
An ton cho thit b nh xng
Mc tiu vn hnh kinh t.
Ta cn phi tm cch loi b tt c cc s c. C nhiu gii php k thut khc
nhau cho vn ny, nhng gii php ny c so snh trn c s ca hai tiu
chun sau nh gi:
Cung cp in lin tc
Cht lng in cung cp
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Thit k b nghch lu cho h thng UPS c kh nng kt ni li
SVTH: Nguyn Vn Chung Lp TB-T1-K51 4
Hot ng nh mt giao din gia h thng cung cp in v nhng ti nhy
cm, UPS cung cp cho ti mt nng lng in lin tc, cht lng cao, khng
ph thuc mi tnh trng ca h thng cung cp.
UPS to ra mt in p cung cp tin cy:
Khng b nh hng ca nhng s c ca h thng cung cp, c bit khi h
thng cung cp ngng hot ng.
Phm vi sai s cho php tu theo yu cu ca nhng thit b in nhy cm.
UPS c th cung cp in p tin cy, c lp v lin tc thng qua cc khu
trung gian: Acquy v chuyn mch tnh.
1.2 Phn loi UPS :
1.2.1 Phn bit theo ch lm vic
a. UPS offline :
Hnh 1.1 Cu trc b UPS offline
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Thit k b nghch lu cho h thng UPS c kh nng kt ni li
SVTH: Nguyn Vn Chung Lp TB-T1-K51 5
Nghch lu ni song song vi h thng cung cp l ngun d tr phng tnh
trng khn cp.
Trong qu trnh vn hnh, ngun li c cung cp trc tip n ti m
khng qua nghch lu.
Nu s c h thng cung cp in hoc in p h thng cung cp in
khng nm trong sai s cho php th ti chuyn t h thng cung cp in
qua nghch lu trong thi gian ngn
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Thit k b nghch lu cho h thng UPS c kh nng kt ni li
SVTH: Nguyn Vn Chung Lp TB-T1-K51 6
Hnh 1.2 Cu trc UPS online
c chn vo gia h thng cung cp v ti. Ton b in nng cung cp
cho ti u phi qua nghch lu do vy vic cung cp in c lin tc
trong phm vi sai s cho php ca f, U.
Khng ph thuc vo trng thi ca h thng cung cp in.
p dng cho ti c cng sut trung bnh P 40 KVA.
1.2.2 Phn loi UPS da theo b chuyn i
Hnh 1.3 Cu trc UPS tnh
a. UPS tnh: S dng b chuyn i tnh thc hin cung cp nng lng.
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Thit k b nghch lu cho h thng UPS c kh nng kt ni li
SVTH: Nguyn Vn Chung Lp TB-T1-K51 7
Gii hn dng trong vn hnh cho php Icp=2.33Im.
Cch li v in.
Bo dng v vn hnh n gin, lm vic tin cy cy chc chn.
Kh nng phn ng tc thi trc nhng dao ng bin ca h thng
cung cp, s dng thit b iu khin vi x l da trn k tht s.
Bin in p iu chnh trong phm vi sai s 0.5% 1%, thi gian
iu chnh nhanh, kch thc v trng lng ca h nh.
b. UPS quay
M G
DK
M G
Power OutputFL
Hnh 1.4 Cu trc UPS quay
Trong : M: ng c
G: My pht
FL: Flywheel (Bnh )
S dng my in quay thc hin bin i nng lng.
Mt b UPS quay hot ng nh vo qun tnh cao ca bnh khi lng ln
(Flywheel energy storage) cung cp nng lng trong trng hp c s c in
ngn hn. Bnh hot ng nh 1 b m chng li s tng hay gim t ngt
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Thit k b nghch lu cho h thng UPS c kh nng kt ni li
SVTH: Nguyn Vn Chung Lp TB-T1-K51 8
ca ngun cung cp v nhng s c ngn hn khng th nh hng ng k n
tc quay ca bnh khi lng ln. y l 1 trong nhng dng thit k c in
nht trong lch s ngnh in.
C th coi UPS quay l mt b UPS online v n hot ng c trong iu kin
bnh thng. Tuy nhin, n ch bo v h thng ti trong khong thi gian t 10
n 20 giy trc khi bnh quay chm xung di mc cho php v u ra b
ngt.
Mt h thng UPS quay tiu biu bao gm cc thnh phn sau:
1 ng c ko 1 my pht in ng b (My pht v ng c c lin kt
v mt c kh nh h thng li hp, ai truyn .v.v.)
Trc quay my pht c gn vi 1 bnh khi lng ln.
Khi h thng xy ra s c ngn hn, ng c b ngt in. Bnh tip tc
quay (do qun tnh ln), do tip tc ko my pht v cung cp in cho
u ra.
1.2.3 S nguyn l chung ca UPS :
NL
K
CL
AQ
+
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Hnh 1.5 S nguyn l chung ca UPS
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Thit k b nghch lu cho h thng UPS c kh nng kt ni li
SVTH: Nguyn Vn Chung Lp TB-T1-K51 9
CL: Cung cp ngun mt chiu cho nghch lu v np thng trc cho acquy
AQ: To nng lng d tr cung cp cho nghch lu khi xy ra:
- Ngng hot ng h thng cung cp.
- H thng cung cp c s c hoc cht lng h thng cung cp khng
nm trong gii hn cho php.
NL: Chuyn i DC AC vi sai s cho php cht ch, chc chn hn h
thng chnh
K: Bao gm c h thng phn hi ,iu khin hot ng ca CL, NL v qu
trnh phng np AQ, n nh cung cp in theo yu cu.
1.3 ng dng ca UPS trong thc t :
Hin nay nhu cu ng dng UPS trong cc lnh vc tin hc, vin thng, ngn
hng, y t, hng khng l rt ln. S lng UPS c s dng gn bng 1/3 s
lng my tnh ang c s dng. C th ly mt vi v d v cc thit b s dng
UPS, l nhng my tnh, vic truyn d liu v ton b thit b mt trng thi
no u l rt quan trng v khng cho php c mt in. UPS c s dng
trong ngnh hng khng m bo s thp sng lin tc ca ng bng sn bay.
ng dng chnh Thit b c bo v
1. H thng my tnh
ni chung
- My tnh, mng my tnh
- My in, h thng v th v cc thit b u cui.
2. H thng my tnh
cng nghip
B iu khin lp trnh, h thng iu khin s, iu
khin gim st, my t ng.
3. Vin thng Tng i in thoi, h thng truyn d liu, h thng
raa.
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Thit k b nghch lu cho h thng UPS c kh nng kt ni li
SVTH: Nguyn Vn Chung Lp TB-T1-K51 10
4. Y t, cng nghip Dng c y t, thang my, thit b o nhit , thit b
iu khin chnh xc
5. Chiu sng ng hm, ng bng sn bay, nh cng cng...
6. Cc ng dng khc My qut hnh, cung cp nng lng cho my bay...
Ni tm li UPS l mt ngun in d phng, n c mt mi ch mi ni,
nhng ni i hi cao v yu cu cp in lin tc.
Bi tm quan trng ca UPS, n ca em c mc tiu thit k b UPS va c
kh nng chy c lp (nghch lu), ng thi c kh nng kt ni vi li in
(ha ng b).
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Thit k b nghch lu cho h thng UPS c kh nng kt ni li
SVTH: Nguyn Vn Chung Lp TB-T1-K51 11
Chng 2: TNH TON THIT K
2.1 Thut ton to sng sin
2.1.1 Phng php to sng iu bin :
C hai phng php to ra sng iu bin :
1. Phng php s dng sng sin cao tn :
c m t bng hnh v sau :
Hnh 2.1 Phng php sng sin cao tn
Nguyn l : s dng sng sin c tn s cao cho giao vi sng sin tn s mong
mun to ra sng iu bin nh hnh v.
2. Phng php s dng sng tam gic :
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Thit k b nghch lu cho h thng UPS c kh nng kt ni li
SVTH: Nguyn Vn Chung Lp TB-T1-K51 12
Hnh 2.2 Phng php sng mang tam gic
Nguyn l: s dng sng tam gic tn s cao cho giao vi sng sin tn s mong
mun to ra sng iu bin.
2.1.2 Nguyn l to sng sin
a) Cu trc mch Half-bridge (Na cu) :
Ls
K1
K2
2
IV
2
IV
RC O
Hnh 2.3 Mch na cu
Ni ti vo im gia hai ngun, khi im gia C ng vai tr l trung tnh .
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Thit k b nghch lu cho h thng UPS c kh nng kt ni li
SVTH: Nguyn Vn Chung Lp TB-T1-K51 13
Theo hnh v trn : khi ta cp tn hiu iu bin sng Sin kch m kha K1 v
K2 th in p t trn in tr s c dng hnh Sin.V bin in p sng Sin
ny l 2
IV
t
Voc(t)V uR
Hnh 2.4 in p to bi mch na cu
b) Cu trc mch Full-Bridge (C cu) :
K1
K2
IVA
Ls RB
Hnh 2.5 Mch c cu
Da vo mch Half-Bridge ta thy rng mch Full-Bridge l s kt hp ca hai
na cu. in p ra trn ti l hiu ca hai in p ti im A v B (uAB = uA uB).
Bin in p ti ph thuc vo gc lch pha gia in p ti im A v im B,
gi s gi gc lch pha l . Suy ra :
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Thit k b nghch lu cho h thng UPS c kh nng kt ni li
SVTH: Nguyn Vn Chung Lp TB-T1-K51 14
.sin( )2
.sin( )2
IA
IB
Vu t
Vu t
AB A Bu u u
.sin( ) .sin( ) [sin( ) sin( )]2 2 2
I I IAB
V V Vu t t t t
Ta thy rng : [sin( t)-sin( t)] 2
Du bng xy ra khi v ch khi : Ott 180)sin()sin(
Vy nn tn hiu sng Sin iu bin phi lch pha nhau 180o bin in p
ra l ln nht .
VA
VB
uAB
Hnh 2.6 ip p to ra bi mch c cu
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Thit k b nghch lu cho h thng UPS c kh nng kt ni li
SVTH: Nguyn Vn Chung Lp TB-T1-K51 15
c) T s iu bin :
Xt t s iu bin bin : l mi quan h gia bin sng sin chun
v sng tam gic, k hiu l ma : pk
ac
Am
Vi A l bin sng sin chun
cpk l bin sng mang tam gic
1,0 2,0 3,0
I
AB
V
V
ma
min tuyn tnh
min tuyn qu
iu bin sng vung
Hnh 2.7 Mi quan h gia t s iu bin bin
T s iu bin tn s: l t s gia tn s sng mang (fpwm) v sng sin
chun (fsin), k hiu t s ny l mf :
pwm
f
c
fm
f
Thng th mf > 9 m bo t l hi trong in p u ra b .
2.1.3 M phng trn Psim :
Cch to ra tn hiu iu bin :
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Thit k b nghch lu cho h thng UPS c kh nng kt ni li
SVTH: Nguyn Vn Chung Lp TB-T1-K51 16
S dng mt tn hiu sin chun giao vi sng tam gic qua b so snh ta s
c c sng iu bin.
Hai tn hiu sng sin chun t lch pha nhau gc 1800
Hnh 2.8 S m phng trn PSim
Hnh 2.9 Dng sng tn hiu iu bin u ra (trc lc)
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Thit k b nghch lu cho h thng UPS c kh nng kt ni li
SVTH: Nguyn Vn Chung Lp TB-T1-K51 17
Hnh 2.10 Dng v p trn in tr R (sau lc)
Nguyn l to sng sin c trnh by trn l c s ta thit k mch ng
lc cho phn nghch lu.
2.2 Cc khi mch s dng
2.2.1 Mch ng lc
C hai la chn chnh cho vic s dng kho ng ct cng sut trong iu
khin ng c l MOSFET v IGBT. C hai loi MOSFET v IGBT u l linh
kin c iu khin bng in p, ngha l vic dn v ngng dn ca linh kin
c iu khin bng mt ngun in p ni vi cc gate ca linh kin thay v l
dng in trong cc b nghch lu s dng transitor nh trc y. V vy cch s
dng loi linh kin ny lm cho vic iu khin tr nn d dng hn.
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Thit k b nghch lu cho h thng UPS c kh nng kt ni li
SVTH: Nguyn Vn Chung Lp TB-T1-K51 18
Ngy nay c nhiu ci tin trong vic sn xut, MOSFET c th hot ng
tn s ng ct cao hn vi RDS(on) nh (khong vi miliohm) lm cho tn tht cng
sut c gim i rt nhiu. V vy ngy nay, a s cc b nghch lu thng s
dng MOSFET hn l IGBT nh trc kia.
Tnh chn van
Cng sut u ra ca mch nghch lu l P = 1kW. in p Ura = 220V.
dng in u ra : dm10000
4,5( )220
PI A
U
in p mt chiu a vo l Vdc = 350V
Chn van cho mch lc ta phi da vo mt s iu kin sau :
i vi van hot ng ch lm mt t nhin (khng c cnh tn nhit).
Dng lm vic ca van bng khong 10% dng in nh mc cho php ca
van. Im = 10%Ivan => Ivan = 10.Im = 10.4,5 = 45(A)
i vi van lm vic ch c cnh tn nhit lm mt, dng in lm vic
ca van cho php khong 30%Im
Ivan = 10
3.Im =
10
3.4,5 = 15 (A)
Nu c cnh tn nhit v lm mt cng bc bng qut gi lm mt dng
lm vic cho php c th ti 70%.Im
Ivan = 10
7.Im =
10
7.4,5 = 6,43 (A)
Nu van lm vic c lm mt cng bc bng nc dng lm vic cho
php c th ti 90%.Im
Ivan = 10
9.Im =
10
9.4,5 = 5 (A)
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Thit k b nghch lu cho h thng UPS c kh nng kt ni li
SVTH: Nguyn Vn Chung Lp TB-T1-K51 19
V van hot ng ch c cnh tn nhit lm mt nn ta chn MOSFET
IRFP460 (vi cc thng s VDSS = 500V, ID = 20A, RDS(on) = 0.27 ).
Hnh 2.11 S Mch lc
S dng 4 Mosfet IRF460, cho php dng in ti nh mc chy qua l 20A,
in p ngc chu ng l 500V, mc s nh hnh v. Gic cm J2 ni vi in
p mt chiu u vo, gic cm J1 l in p iu bin u ra, J3 v J4 ni vi
mch li nhm iu khin 4 van lc m v kha, ng thi n cng gip np in
p cho hai t booststrap.
2.2.2 Mch li
C hai s la chn cho cc kha ng ngt cng sut to ra sng sin l
MOSFET v IGBT v kh nng chu dng v p cao. Ni chung, khi s dng cc
kha ng ngt (MOSFET, IGBT ) iu khin th u cn dng n mch li
(gate drive scheme). C 2 phn c bn trong vic iu khin cc ng ngt linh
kin cng sut l: iu khin pha cao (high side Q1) v pha thp (low side Q2).
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Thit k b nghch lu cho h thng UPS c kh nng kt ni li
SVTH: Nguyn Vn Chung Lp TB-T1-K51 20
Hnh 2.12 V d s iu khin MOSFET
Trong v d trn Q1 v Q2 lun trng thi lm vic i nghch nhau. Khi Q1
trng thi ON th Q2 trng thi OFF v ngc li. Khi Q1 ang trng thi
OFF chuyn sang trng thi ON => chn S ca Q1 chuyn t ground sang in p
cao (high voltage rail). Do mun kch Q1 tip tc ON th phi to in p kch
VGS1 c gi tr VGS1= VSQ1 + V. Trong khi tn hiu ra ca vi x l iu
khin ng ngt cc kha ch c gi tr in p +3.3V (so vi ground). Nn cn
phi c mch li to tri p v cch ly trong vic ng ngt pha cao Q1. Tuy
nhin i vi Q2 th chn S c ni ground, do in p kch VGS2 ch cn c
gi tr V. Do vic ng ngt kha low side (Q2) c iu khin d dng hn.
y ta thit k mch li dng IC li IR2110.
Hnh 2.13 Mch li
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Thit k b nghch lu cho h thng UPS c kh nng kt ni li
SVTH: Nguyn Vn Chung Lp TB-T1-K51 21
S dng 2 IC li IR2110, th t cc chn c ni nh hnh v trn, ngun cp
cho n l 5V v 15V, c to bi IC n p 7805 v 7815 ni n trn. Cc
u vo 10 v 12 c ni vi u ra ca mch cch ly. T C2 v C4 l cc t
bootstrap. u ra ca gim J1 v J4 c ni ti iu khin mch lc.
Gii thiu IC IR2110
IR2110 l loi IC chuyn dng li MOSFET v IGBT ca hng IR
(International Rectifier). IC ny c 1 knh output (mi knh gm high side
v low side) c th li cho mt nhnh ca cu bn dn.
2.2.3 Mch iu khin
Dng vi iu khin dsPIC33FJ12MC202 (y l 1 loi vi iu khin kh mnh
v s c trnh by r hn phn sau).
Mch iu khin c nhim v pht ra xung iu khin iu khin cc kha
bn dn ca b nghch lu ba pha qua mch cch ly v mch li.
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Thit k b nghch lu cho h thng UPS c kh nng kt ni li
SVTH: Nguyn Vn Chung Lp TB-T1-K51 22
Hnh 2.14 Mch iu khin
Mch gm ngun 3,3V cp vo chn VDD v chn AVDD ca vi iu khin, b
to xung dao ng thch anh 7,37MHz c ni vo chn 9 v chn 10. Chn c
tn hiu phn hi ADC c ni vo chn 2. Cc chn 4 (PGD1), chn 5 (PGC1),
chn MCLR dng np chng trnh cho vi iu khin. Cc u ra ca tn hiu
PWM nm cc chn 23, 24, 25, 26.
2.2.4 Mch cch ly
Cc mch pht ra tn hiu iu khin mch cng sut bn dn phi c cch
ly v in. iu ny c th thc hin c bng mch cch ly quang hoc bng
bin p xung. Mch cch ly l phn ni gia mch iu khin v mch li.
Bin p xung :
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Thit k b nghch lu cho h thng UPS c kh nng kt ni li
SVTH: Nguyn Vn Chung Lp TB-T1-K51 23
Gm mt cun dy s cp v c th nhiu cun th cp. Vi nhiu cun dy
pha th cp, ta c th kch ng nhiu transistor mc ni tip hoc song song. Bin
p xung cn c cm khng tn nh v p ng nhanh. Trong trng hp xung iu
khin c cnh tc ng ko di hoc tn s thp, bin p xung sm t trng thi
bo ha v ng ra ca n khng ph hp yu cu iu khin.
Cch ly quang (Opto):
Gm ngun pht tia hng ngoi dng diode (IR-LED) v mch thu dng
phototransistor. Do tha mn yu cu cch ly v in, ng thi p ng ca
opto tt hn my bin p xung.
n gin v tin dng, ta chn phng n dng opto. Vi tn s ng ct cao
(10kHz), ta s dng cch ly quang 6n137.
Hnh 2.15 Mch cch ly
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Thit k b nghch lu cho h thng UPS c kh nng kt ni li
SVTH: Nguyn Vn Chung Lp TB-T1-K51 24
Mch dng 4 cch ly quang 6n137 c nui bng ngun 5V, u vo cc cch
ly quang l cc xung PWM a vo t mch iu khin nh J2, 4 chn ra 7 s a
vo mch li li MOSFET.
2.3 Tnh ton mch lc thng thp
2.3.1 S cn thit ca mch lc thng thp
Khi thit k mch nghch lu ta mong mun in p u ra c tn s l 50Hz.
Do in p iu bin u ra ca cu nghch lu l tp hp ca cc thnh phn tn s
bc nht v bc cao. Nn c c in p u ra 50Hz ta phi loi b i thnh
phn tn s bc cao.
thc hin iu ny ta s dng mch lc thng thp c dng nh di hnh
v, gm hai thnh phn L v C.
2.3.2 Tc dng ca C v L trong mch lc
Ta bit ZL = 2.f.L , nn khi tn s f tng, dn n ZL tng, hay ni cch khc
n ngn khng cho nhng tn s bc cao i qua.
Tng t 1
2. . .CZ
f C, khi tn s tng , dn n ZC gim, do ZC mc song song
vi ti nn n c xu hng cho thnh phn bc cao chy qua v trit tiu n.
2.3.3 M hnh ton tnh ton gi tr L v C
Khi tnh ton gi tr cun lc v t lc, do in tr cun lc rt nh nn ta c th
b qua. Khi ta c m hnh mch lc:
-
Thit k b nghch lu cho h thng UPS c kh nng kt ni li
SVTH: Nguyn Vn Chung Lp TB-T1-K51 25
uvao
L
uraLaplace
urauvao
Ls
C 1/Cs
Hnh 2.16 Bin i Laplace
Theo s mch ta c :
1( ) ( . )
.vaou s I L s
C s
1( ) .
.rau s I
C s
21
( ). 1
ra
vao
uK s
u LC s
Nn hm truyn ca mch lc c dng nh sau: 21
( ). 1
K sLC s
2 21 1
( )( ) 1 1
K jLC j LC
Bin hm truyn : 21
| ( ) ||1 |
K jLC
Xt : L()=20. log |K(j)|
L() = - 20. log |1- LC2|
Xt biu thc : L() = - 20. log |1- LC2|
-
Thit k b nghch lu cho h thng UPS c kh nng kt ni li
SVTH: Nguyn Vn Chung Lp TB-T1-K51 26
Khi : 0 L1 () = 0
Khi : + LC2 >>1
L() - 20.logLC 40.log
Hai ng ny ct nhau ti im :
1
.L C
Biu din trn th :
L()
L()
C
-40dB
(rad/s)
Hnh 2.17 th bode
2.3.4 Tnh ton gi tr L v C
Chn tn s ct : fc = 1000 Hz
c= 2..fc = 2..1000 = 6283,2 (rad/s)
Do ti u song song vi C nn phi chn L v C sao cho : Zc>> ZL m bo
cho khi y ti in p ri trn L l b v in p p trn C l ln nht.
Nu UL = 5V v dng khi y ti I = 5,05A suy ra : ZL = 5/5,05= 0,99 ().
ng vi = 2..f = 2..50 = 314,16 (rad/s)
-
Thit k b nghch lu cho h thng UPS c kh nng kt ni li
SVTH: Nguyn Vn Chung Lp TB-T1-K51 27
ax0,99
3,15( )2. .50
Lm
ZL mH
6
min 2 3 2
ax
1 18,06.10 ( )
. 3,15.10 .6283,2m cC F
L
Chn C = 10 F = 10.10-6 F
3
2 6 2
1 12,54.10 ( )
. 10.10 .6283,2cL H
C
32. . . 2. .50.2,54.10 0,798( )LZ f L
61 1
318,3( )2. . . 2. .50.10.10
CZf C
R rng iu kin: ZC >> ZL c tha mn.
2.3.5 Thit k cun khng lc
Vi cc thng s thng s nh mc:
Dng nh mc chy qua cun khng : I = 5,05 A
St p trn cun khng :U = 5 V
Tn s hot ng: f = 50 Hz
Mt t cm : B = 0,3 0,5 T, ta chn B = 0,4 T
T cm : L = 2,54 mH
Vt liu li : Ferrite
H s dng sng : Kf = 4,44 ( Dng sng hnh sin)
H s lp y: Ku = 0,4
Mt dng in: J = 700 A/cm2
-
Thit k b nghch lu cho h thng UPS c kh nng kt ni li
SVTH: Nguyn Vn Chung Lp TB-T1-K51 28
Theo nhng thng s nh mc trn, ta tin hnh lp t ni tip 2 cun khng
c thng s ging nhau. Khi st p trn mi cun l 2,5V, v t cm mi cun
l 1,27 mH.
Cng sut cun khng:
VA = U.I = 2,5.5,05 = 12,625 (W)
4 4.10 12,625.10
5,08. . . . 4,44.0,4.50.0,4.700
p
f u
VAA
K K f B J
Tra bng mch t dng ETD ng vi Ap va tm c ta chn li ETD49 vi
cc thng s:
- Chiu di ng sc t : MPL = 11,4 cm
- Trng lng li : WtFe = 124 grams
- Chiu di trung bnh vng dy : MLT = 10,3 cm
- Tng din tch mt ct cc cc t : Ac = 2,11 cm2
- Din tch ca s mch t : Wa = 3,434 cm2
- Mch t : Ap = 7,2453
- Chiu cao cun dy : G = 3,54 cm
- Chiu rng cc t chnh : E = 1,67 cm
Tnh s vng dy:
4 4.10 2,5.10133,4( ng)
. . . 4,44.0,4.50.2,11f c
UN v
K B f A
Chn N = 133 vng
Khong cch khe h khng kh:
-
Thit k b nghch lu cho h thng UPS c kh nng kt ni li
SVTH: Nguyn Vn Chung Lp TB-T1-K51 29
2 8 2 8
3
0,4. . . .10 0,4. .133 .2,11.100,37( )
1,27.10
cg
N Al cm
L
Tnh t tn:
2 0,37 2.3,54
1 .ln 1 .ln 1,7520,372,11
g
gc
l GF
lA
S dng kt qu va tnh c tnh li s vng dy:
3
8 8
. 0,37.1,27.10' 101( ng)
0,4. . . .10 0,4. .2,11.1,752.10
g
c
l LN v
A F
S dng s vng dy mi tnh li mt t cm:
4 4.10 2,5.100,52( )
. '. . 4,44.101.50.2,11f c
UB T
K N f A
Tnh tit din dy qun:
3 25,05 7,21.10 ( )
700
IS cm
J
Chn dy c ng knh d = 1 mm => Tit din dy Aw = 7,854.10-3
(cm2)
Tnh li h s lp y:
3
w
a
'. 101.7,854.100,3
W 3,434u
N AK
in tr cun khng lc:
6 6. '. .10 10,3.101.219.10 0,228( )R MLT Ncm
-
Thit k b nghch lu cho h thng UPS c kh nng kt ni li
SVTH: Nguyn Vn Chung Lp TB-T1-K51 30
Chng 3: XY DNG KHU IU CHNH IN P
3.1 Nguyn l chung ca khu t ng iu chnh in p :
Hnh 3.1 S khi h thng
3.2 Xy dng m hnh ton cho cc khu ca mch nghch lu :
3.2.1 Xy dng mi quan h gia rng xung d (Duty Cycle) v in p u
ra :
Hnh 3.2 M hnh cu H
Suy ra s mch c dng n gin nh sau :
-
Thit k b nghch lu cho h thng UPS c kh nng kt ni li
SVTH: Nguyn Vn Chung Lp TB-T1-K51 31
Hnh 3.3 Bin i Laplace
Tng tr ca mch c tnh nh sau :
CssIsu
Cs
RsLCsZ
CsRLsZ OO
1).()(
11 2
Vi : ( )
( ) ABOu s
I sZ
( Vi uAB l dng in p iu bin )
2 2
( ) 1 1'( ) . '( )
( ) ( ) 1 ( ) 1
O
AB
u s CsG s G s
u s LC s RCs Cs LC s RCs
(R l in tr cun cm)
Quan h gia in p u ra vi rng xung d :
-
Thit k b nghch lu cho h thng UPS c kh nng kt ni li
SVTH: Nguyn Vn Chung Lp TB-T1-K51 32
VA
VB
uAB
Hnh 3.4 in p ra UAB
Ta c :
1 1
1 1( ) . ( ) ( ) .( . . ( )) ( ) . ( )
t T
A A A DC A DC
t
V t V d V t T V d t V t V d tT T
(d1 l rng xung trong mt chu k pwm ca VA)
2 2
1 1( ) . ( ) ( ) .( . . ( )) ( ) . ( )
t T
B B B DC B DC
t
V t V d V t T V d t V t V d tT T
(d2 l rng xung trong mt chu k pwm ca VB)
Suy ra : 21. dVdVVVu DCDCBAAB
dVuddVu DCABDCAB .).( 21 ( trong d = d1-d2 )
DCAB
Vd
tu )(
-
Thit k b nghch lu cho h thng UPS c kh nng kt ni li
SVTH: Nguyn Vn Chung Lp TB-T1-K51 33
Do : 1
1.
)()(
2 RsLCsV
d
tusG DC
O
3.2.2 Xc nh hm truyn ca khi PWM :
ZOHm(t)
T
m (t)s
c(t)
V (t)MO
C(t),m(t)
cpkm(t)
ms(t)
t
t
VMO(t)
Hnh 3.5 M hnh PWM
Khu PWM c xp x nh mt khu t l nn ta c hm truyn ca n nh sau:
pk
MO
csM
sVsPWM
1
)(
)()( , cpk l bin sng mang
3.2.3 S khi m t vng kn ca b nghich lu :
Hnh 3.6 S vng kn
-
Thit k b nghch lu cho h thng UPS c kh nng kt ni li
SVTH: Nguyn Vn Chung Lp TB-T1-K51 34
xc nh cc h s ca khu iu chnh Kp, Kd ta s dng tiu chun Nyquist
p dng cho hm truyn h h.
3.2.4 Tiu chun Nyquist :
Hm truyn h h:
21
( ) ( . ). . .. . 1
DCh p d u
pk
VG s K K s G
c LC s RC s
21
( ) ( ). . .1
DCh p d u
pk
VG j K j K G
c LC j RC
Tiu chun Nyquits h kn n nh:
Bin ca hm truyn h h tn s ct phi bng 1
|Gh(j c)| = 1
Gc pha ca h h tn s ct phi ln hn -180o
c = arctg Gh(j c) > -180o
Ta c: Vdc=350V; Gu=1/311; L=2,54mH; C=10 F; R=0,228
chn fc = 2kHz ( c=2 fc), cpk = 1
Kp = 1,7 v Kd = 1,343.10-4
Hm truyn h h:
4
8 2 6
1,694.10 . 2,129( )
2,54.10 . 2, 2.10 1h
sG s
s
-
Thit k b nghch lu cho h thng UPS c kh nng kt ni li
SVTH: Nguyn Vn Chung Lp TB-T1-K51 35
Hnh 3.7 Biu bode
-
Thit k b nghch lu cho h thng UPS c kh nng kt ni li
SVTH: Nguyn Vn Chung Lp TB-T1-K51 36
Hnh 3.8 S khi m phng matlab
Hnh 3.9 Kt qu m phng
-
Thit k b nghch lu cho h thng UPS c kh nng kt ni li
SVTH: Nguyn Vn Chung Lp TB-T1-K51 37
Chng 4. NGHIN CU CC MODULE C BN CA
DSPIC33FJ12MC202
4.1 Tng quan v vi iu khin dsPIC33FJ12MC202:
Microchip l nh nh sn xut vi iu khin v cc thit b bn dn hng u th
gii. Microchip ch trng vo cc sn phm p ng nhu cu ca th trng iu
khin nhng. Hin nay Microchip l nh cung cp dn u v cc sn phm sau:
Vi iu khin 8 bit thng dng (PICMCUs)
Cc vi iu khin 16 bit v 32 bit
Cc b iu khin tn hiu s dng dsPIC 16 bit.
Cc b nh bn, chun v chuyn dng.
Cc thit b bo v.
Cc thit b cho nhng ng dng c bit.
Cc dng dsPIC rt a dng, trong n ny, vi iu khin c s dng l
dsPIC33FJ12MC202 vi cc thng s sau:
-
Thit k b nghch lu cho h thng UPS c kh nng kt ni li
SVTH: Nguyn Vn Chung Lp TB-T1-K51 38
MCU dsPIC33FJ12MC202 c thit k da trn kin trc RISC, c th hot
ng vi 40 MIPS (triu lnh/giy) di in p (3.0V- 3.6V), cng sut thp
c th hot ng tc cao p ng c cc ng dng c yu cu tc
tnh ton nhanh v yu cu chnh xc cao.
Tp lnh gm c 83 ch lnh
C b nh RAM l 1024 bytes, b nh FLASH l 12K.
Hot ng ch ngun dao ng ngoi (External Clock) ti a l 40Mhz
Hot ng ch dao ng thch anh tn s t 4Hhz-8Mhz vi cc cp
nhn PLL(Phase Locked Loop) c th cu hnh vi cc b nhn khc nhau
ty theo cch thit lp chng trnh m dao ng thc s a vo trong MCU
c th ln n 80Mhz.
MCU dsPIC33F c 118 ngun ngt, mi ngun ngt c 7 cp ngt u tin
Gm c 2 port I/O (A,B) (cng vo/ ra)
3 b Timer/Counter 16 bits, trong c th ghp li vi nhau thnh cc b
Timer/Counter 32 bits
c tch hp cc moudle Compare/ Capture, c 8 knh PWM
Moudle I2C h tr ch Multi-Master/Slave, 7 bits/10 bits xc nh a ch
Ngoi ra cn tch hp cc chun giao tip CAN, UART v 3-wire SPI
6 knh 10 bits - Analog to Digital Converter tc cao (1.1 Msps) hoc 12
bits tc 500 Ksps, c kh nng chuyn i trong lc MCU trng thi
Sleep, Idle.
4.2 Cu trc vi iu khin :
Parameter Name Thng s Value (Gi tr)
-
Thit k b nghch lu cho h thng UPS c kh nng kt ni li
SVTH: Nguyn Vn Chung Lp TB-T1-K51 39
Architecture Cu trc 16-bit
CPU Speed (Microchips) Tc CPU 40
Memory Type Dng b nh Flash
Program Memory (KB) Dung lng b nh 12
RAM Bytes S byte RAM 1,024
Temperature Range C Di nhit hot ng -40 to 125
Operating Voltage Range (V) Di in p hot ng 3 to 3.6
I/O Pins S chn vo/ra 21
Pin Count Tng s chn 28
System Management
Features
Tnh nng qun l h
thng
PBOR
Internal Oscillator B dao ng ni 7.37 MHz, 512 kHz
Digital Communication
Peripherals
Cc ngoi vi giao tip s 1-UART, 1-SPI, 1-
I2C
Analog Peripherals Cc ngoi vi tng t 1-A/D 6x10-bit @
1100(ksps)
16-bit PWM resolutions Tc x l PWM 16
-
Thit k b nghch lu cho h thng UPS c kh nng kt ni li
SVTH: Nguyn Vn Chung Lp TB-T1-K51 40
Motor Control PWM
Channels
Cc knh PWM iu
khin ng c
8
Timers B nh thi 3 x 16-bit 1 x 32-bit
Hnh 4.1 S chn ca dsPIC33FJ12MC202
4.3 T chc b nh:
Vng nh chng trnh c t chc thnh cc khi truy cp c theo t. Mc
d c coi l c rng 24 bits nhng chng ta nn coi mi a ch ca b nh
chng trnh gm c t thp v t cao, trong nhng byte cao ca t cao khng
c s dng. T thp lun lun c a ch chn trong khi t cao lun c a ch l.
Vng nh d liu:
CPU ca dsPIC33FJ12MC202 c vng nh d liu 16 bits ring bit. Vng nh
d liu c truy cp bng cch s dng khi pht a ch (Address Generation
-
Thit k b nghch lu cho h thng UPS c kh nng kt ni li
SVTH: Nguyn Vn Chung Lp TB-T1-K51 41
Units) c v ghi cc php tnh ton. Bn b nh d liu c cho hnh di
y:
MSB
address
16 bits
LSB
addressMSb LSb
SFR Space
X Data RAM(X)
Y Data RAM(Y)
X Data
unimplemented
(X)
0x0001 0x0000
0x07FE
0x0800
0x07FF
0x0801
0x0BFE
0x0C00
0x0BFF
0x0C01
0x01FFF
0x2001
0x1FFE
0x2000
0x07FF
0x0801
0x09FF
0x0A01
2 Kbyte SFR
Space
1 Kbyte
SFR
Space
8 Kbyte
Near
Data Space
0x800
10x8000
0xFFFF 0xFFFE
Hnh 4.2 T chc b nh ca dsPICFJ12MC202
4.4 Khi qut v cc thanh ghi:
Tt c cc chn I/O trn MCU ( ngoi tr cc chn VDD, VSS, AVDD, AVSS,
MCLR, OSC1/CLK1) c th va ng vai tr l chc nng tng qut (General
Purpose) va c ng vai tr s dng t bit. Cc chc nng tng qut cho php
dsPIC33F gim st v iu khin cc thit b khc. Hu ht cc I/O u c kt hp
nhiu chc nng ring bit khc nhau. S kt hp cc chc nng ny ty thuc vo
-
Thit k b nghch lu cho h thng UPS c kh nng kt ni li
SVTH: Nguyn Vn Chung Lp TB-T1-K51 42
c im trn loi MCU xc nh. V khi mt I/O c s dng vi chc nng
chuyn bit th I/O c th s khng th c s dng vi chc nng tng qut.
4.4.1 Cc thanh ghi iu khin :
Tt c cc I/O Port trong MCU thuc h 12F, 16F,18F,30F ... u c 3 thanh
ghi trc tip lin quan n phng thc hot ng ca cc Port , cc thanh ghi
l TRISx, PORTx, LATx, trong x l tn tng ng ca cc Port trong MCU.
Mi chn I/O u c mt bit tham chiu tng ng trong ba thanh ghi trn.
4.4.2 Thanh ghi TRIS:
Cc bits iu khin trong thanh ghi TRIS xc nh trng thi hot ng ca cc
I/O l input hay output. Nu bit TRIS ca mt I/O l 1 th I/O s ng vai tr nh
l mt ng input, ngc li nu bit TRIS ca mt I/O l 0 th I/O s ng vai tr
nh l mt ng output. iu cn lu l tt c cc I/O s ng vai tr l input ngay
sau khi MCU b Reset.
4.4.3 Thanh ghi PORT:
D liu trn mt I/O c truy xut thng qua thanh ghi PORT, s kin c
thanh ghi PORTx s c gi tr ca ca I/O tng ng v s kin ghi vo thanh ghi
PORTx s ghi gi tr vo Port cht d liu.
Mt s lnh nh BSET v BCLR l cc lnh cho php Read-Modify-Write d
liu trn cc Port. Vic ghi vo mt Port ngha l cc I/O ca Port s c c
vo, gi tr s c hiu chnh li, sau c ghi vo Port cht d liu.Mt
iu cn ch l khi cc lnh Read- Modify-Write s dng trn mt thanh ghi
PORTx th cc I/O c lin quan ca Port phi c cu hnh nh l ng input.
Nu mt I/O c cu hnh nh l ng input b chuyn sang cu hnh l output
-
Thit k b nghch lu cho h thng UPS c kh nng kt ni li
SVTH: Nguyn Vn Chung Lp TB-T1-K51 43
trong khi thc hin cc lnh Read-Modify-Write th s dn n nhng kt qu khng
mong mun trn I/O .
4.4.4 Thanh ghi LAT:
Thanh ghi LATx lin quan n mt chn I/O hn ch cc s c c th xy ra i
vi cc lnh Read-Modify-Write. Vic c thanh ghi LAT s tr v gi tr c ct
gi trong Port cht ng ra ( Port output latches), thay v gi tr trn chn I/O port.
Lnh Read-Modify-Write trn thanh ghi LAT, lin quan n mt I/O, trnh kh
nng ghi gi tr ca chn input vo Port cht. V trnh t ghi vo thanh ghi LATx
cng tng t nh trn.
S khc nhau gia thanh ghi PORT v LAT c th c tm tt nh sau:
Vic ghi vo thanh ghi PORTx s ghi gi tr d liu vo Port cht (Port latch)
Vic ghi vo thanh ghi LATx s ghi gi tr d liu vo Port cht
Vic c t thanh ghi PORTx s c gi tr d liu trc tip trn chn I/O
Vic c t thanh ghi LATx s c gi tr d liu c ct gi trong Port
cht.
4.5 Gii thiu cc module c bn
4.5.1 Module to dao ng ca dsPIC33FJMC202 (oscillator) :
Cu trc b dao ng:
H thng b dao ng ca h dsPIC33F c cc c im sau:
- Ty chn gia 4 b dao ng ngoi v 1 b dao ng ni.
- B nhn tn s y tn s lm vic trong vi iu khin ln ti tn s ngun
dao ng ngoi (ni) chn.
- Cng tc chuyn i gia cc ngun dao ng.
-
Thit k b nghch lu cho h thng UPS c kh nng kt ni li
SVTH: Nguyn Vn Chung Lp TB-T1-K51 44
- Ch tit kim in (doze mode)
Ngun dao ng ca h thng c th c cung cp bi 1 trong cc ngun sau:
- Ngun dao ng s cp (POSC) cc chn OSC1 v OSC2.
- Ngun dao ng th cp (SOSC) cc chn SOSC1 v SOSC2.
- B dao ng FRC (Internal Fast RC)
- B dao ng LPRC (Internal Low Power RC)
Cu hnh cho b nhn tn s:
Cc ngun dao ng POSC v FRC c th s dng 1 b nhn tn s tch hp trn
chip (Phase Locked Loop) t c tc lm vic cao hn. S khi b nhn
tn s cho hnh sau:
N1
M
N2VCOPFD
0.8
-
Thit k b nghch lu cho h thng UPS c kh nng kt ni li
SVTH: Nguyn Vn Chung Lp TB-T1-K51 45
Bit PLLPRE trong thanh ghi chia tn s (CLKDIV) xc nh t s
chia u vo (N1), c dng gim tn s u vo (FIN)sao cho tha mn c
yu cu: tn s u vo khi FPD nm trong di 0,8-8MHz.
Bit PLLDIV trong thanh ghi chia phn hi (Clock Divisor register
PLLFBD) xc nh t s M, dng xc nh t l gim FVCO cho tn hiu phn
hi ca khi PFD: FVOC = M.FREF.
Bit PLLPOST trong thanh ghi chia tn s (CLKDIV) xc nh t s
chia N2, dng gii hn FOSC ngng di 80 MHz.
Phng trnh sau th hin mi quan h gia FIN v FOSC:
OSC
1 2
2( ) ( )
. ( 2).2.( 1)IN IN
M PLLDIVF F F
N N PLLPRE PLLPOST
Trong : N1 = PLLPRE+2
N2 =2.(PLLPOST +1)
M = PLLDIV+2
Phng trnh th hin mi quan h gia FIN v FVCO:
VCO
1
2( ) ( )
2IN IN
M PLLDIVF F F
N PLLPRE
Thit lp b nhn tn s hot ng vi b dao ng s cp POSC:
Di y l quy trnh thit lp b nhn tn s c th s dng vi iu khin
tc 40Mbps vi thch anh gn ngoi (tn s dao ng 10MHz):
1. thc hin lnh 40MHz, cn m bo rng tn s dao ng ca h
thng l: FOSC = 2.FCY = 80MHZ.
-
Thit k b nghch lu cho h thng UPS c kh nng kt ni li
SVTH: Nguyn Vn Chung Lp TB-T1-K51 46
2. m bo rng gi tr reset mc nh ca PLLPRE, PLLPOST v PLLDIV
phi ph hp vi b PLL v yu cu ca ngi dng.
3. Nu b PLL ph hp vi yu cu ca ngi dng, ta cu hnh trc tip
bit FNOSC
-
Thit k b nghch lu cho h thng UPS c kh nng kt ni li
SVTH: Nguyn Vn Chung Lp TB-T1-K51 47
(AVDD/AVSS) hoc mc in p trn cc chn ( VREF+/VREF-) . B ADC c kh
nng hot ng khi CPU ang trong trng thi ng (Sleep Mode)
Module ADC c iu khin bi vic thit lp cho cc thanh ghi sau :
AD1CON1: ADC1 CONTROL REGISTER 1
AD1CON2: ADC1 CONTROL REGISTER 2
AD1CON3: ADC1 CONTROL REGISTER 3
AD1CHS123: ADC1 INPUT CHANNEL 1, 2, 3 SELECT REGISTER
AD1CHS0: ADC1 INPUT CHANNEL 0 SELECT REGISTER
AD1CSSL: ADC1 INPUT SCAN SELECT REGISTER LOW
AD1PCFGL: ADC1 PORT CONFIGURATION REGISTER LOW
Module bao gm b nh m kp 16-word (16-word dual port read-only
buffer), y l b nh ch c dng cha gi tr ca vic chuyn i tng t - s.
Ni dung ca 16 thanh ghi trong b nh m ( t ADCBUF0 n ADCBUFF) khng
th dc ghi vo bi ngi s dng.
Sau khi Module ADC c thit lp xong, vic thu thp mu c bt u
bng vic set bit SAMP. Mt s tc ng nh l cc bit lp trnh (Programable
bit), s kin ngoi (external events), trn timer (timer time-out), s kt thc vic
thu thp mu v bt u qu trnh chuyn i. Khi s chuyn i hon tt, kt qu s
c a vo cc thanh ghi trong b nh m t ADCBUF0ADCBUFF. C bo
ADIF v bit DONE s c set sau mt s ln ly mu c xc nh bi bit SMPI
b) Khi to hot ng cho module ADC :
-
Thit k b nghch lu cho h thng UPS c kh nng kt ni li
SVTH: Nguyn Vn Chung Lp TB-T1-K51 48
1. La chn chn dng c tn hiu ADC . iu ny c thc hin
thng qua vic cu hnh cc thanh ghi ADxPCFGH hoc thanh ghi
ADxPCFGL.
2. La chn in p tham chiu ph hp vi gii gi tr ADC u vo. Vic
ny c thc hin da vo cu hnh cho thanh ghi ADxCON2.
3. La chn xung clock cho hot ng ca b ADC da vo thanh ghi
ADxCON3.
4. Thanh ghi ADxCON2 v thanh ghi ADxPCFGH hoc thanh
ghi ADxPCFGL quyt nh xem bao nhiu qu trnh ly mu
v gi mu xy ra trn mt ln ngt.
5. Vic la chn tun t ly mu trong trng hp ta cn s dng nhiu tn
hiu ADC u vo s c cu hnh trong thanh ghi ADxCON1 v
ADxCON3.
6. La chn cch lu gi tr chuyn i ADC vo thanh ghi m (buffer)
c thc hin bng cch cu hnh trong thanh ghi ADxCON1.
7. Bit nm trong thanh ghi ADxCON1 s khi ng module ADC hot
ng.
8. Cu hnh cho ngt ADC gm hai th tc nh sau :
- Xa bit ADxIF
- La chn u tin ngt ADC.
c) Tun t chuyn i mu nh sau :
-
Thit k b nghch lu cho h thng UPS c kh nng kt ni li
SVTH: Nguyn Vn Chung Lp TB-T1-K51 49
Sample Time Conversion Time
SOC
Trigger
SAR
ADC+
-+
-
Hnh 4.4 Trnh t trch mu v chuyn i
Theo hnh v trn ta c trnh t nh sau :
1. Tn hiu in p u vo c kt ni vi t ly mu.
2. T ly mu b ngt kt ni vi u vo
3. in p lu gi trong t ly mu s c chuyn i tng ng thnh
gi tr s.
d) Thi gian ly mu :
iu ny ph thuc vo cch la chn gi tr np vo bit ADxCON1 :
ASAM Start of Sampling Selection
0 Trch mu bng tay
1 Trch mu t ng
e) Thi gian chuyn i :
Thi gian chuyn i ph thuc vo vic ta la chn phn gii cho gi tr ADC
( 12bit hoc 10bit ) v xung clock dng cung cp cho b ADC .
i vi b ADC 10bit : TCONV =12.TAD
-
Thit k b nghch lu cho h thng UPS c kh nng kt ni li
SVTH: Nguyn Vn Chung Lp TB-T1-K51 50
Trong : TCONV = Conversion Time (Thi gian chuyn i)
TAD = Chu k b ADC
i vi b ADC 12bit : TCONV = 14.TAD
TAD c xc nh nh sau :
N
ADC Internal RC
TCY
ADRC
ADC Clock (TAD)
0
1ADCS
Hnh 4.5 Cng thc xc nh chu k hot ng ca b ADC
Khi ADCS=1 th TAD =TCY.(ADCS+1)
Trong : TCY l tn s m lnh.
Gi tr ca ADRC c np vo bit 15 ca thanh ghi AD1CON3
f) Hm chuyn i ADC v gi tr thc :
Da vo gi tr in p max v min ca in p tham chiu ng thi phn gii
ta suy ra c gi tr thc.
-
Thit k b nghch lu cho h thng UPS c kh nng kt ni li
SVTH: Nguyn Vn Chung Lp TB-T1-K51 51
Output code
11 1111 1111 (=1023)
11 1111 1111 (=1023)
(A)(B)
(C)
(D)
(E)
00 0000 0000 (=0)
00 0000 0001 (=1)
10 0000 0011 (=515)
10 0000 0010 (=514)
VREFL
1024
REFH REFL
REFL
V VV
512
1024
REFH REFL
REFL
V VV
1023
1024
REFH REFL
REFL
V VV
VREFH
Hnh 4.6 Ch 10 bits
Output code
1111 1111 1111 (=4095)
1111 1111 1110 (=4094)
(A)(B)
(C)
(D)
(E)
0000 0000 0000 (=0)
0000 0000 0001 (=1)
1000 0000 0011 (=2051)
1000 0000 0010 (=2050)
VREFL
4096
REFH REFL
REFL
V VV
2048
4096
REFH REFL
REFL
V VV
1023
4096
REFH REFL
REFL
V VV
VREFH
1000 0000 0001 (=2049)
0111 1111 1111 (=2047)
0111 1111 1110 (=2046)
0111 1111 1101 (=2045)
0111 1111 1100 (=2044)
Hnh 4.7 Ch 12 bits
-
Thit k b nghch lu cho h thng UPS c kh nng kt ni li
SVTH: Nguyn Vn Chung Lp TB-T1-K51 52
4.5.3 Module Timer:
MCU dsPIC33FJ12MC202 cung cp 3 module timer 16 bits, mi module
Timer/Counter 16 bit u c cc thanh ghi ch c( Reable/Writeable Register):
- TMRx: l thanh ghi 16 bit, dng lu gi tr hin ti ca Timer tng ng.
- PRx: l thanh ghi 16 bit, dng np gi tr m cho Timer.
- TxCON: l thanh ghi iu khin 16 bit, dng thit lp cc thng s iu
khin, ch hot ng ca Timer.
Mi Module Timer u c cc bits lin quan dng cho phc v ngt:
- Interrupt Enable Control bit(TxIE): kch hot hoc ngng kch hot Timer.
- Interrupt Flag Status bit(TxIF): bo khi trn b m.
- Interrup Priority Control bit( TxIP): t cc mc u tin cho ngt Timer.
Cc timer c phn thnh cc loi sau:
Module Timer 1:
Timer 1 module l mt timer 16 bits , c th c s dng lm b m thi gian
cho thi gian thc (Real Time Clock), hoc c th c vn hnh nh l b nh
thi ni b (interval timer), b m (counter), b 16-bits Timer1 c cc ch :
- Ch nh thi 16 bits (16-bits Timer)
- Ch b m ng b 16 bits (16-bits Synchronous Counter)
- Ch b m bt ng b 16 bits (16-bits Asynchronous Counter)
S kin ngt Timer: 16-bit TIMER c kh nng to ra ngt . Khi gi tr ca Timer
bng vi gi tr trong thanh khi PR1 th bit T1IF s c tc ng v to ra ngt. V
nu c kch hot, bit T1IF phi c xo bng phn mm. C ngt Timer T1IF
c t trong thanh ghi iu khin IFS0 .
-
Thit k b nghch lu cho h thng UPS c kh nng kt ni li
SVTH: Nguyn Vn Chung Lp TB-T1-K51 53
Module Timer 2/3:
Module Timer 2/3 l mt 32-bit Timer v c th c thit lp thnh 2 Timer 16
bits ring bit l Timer 2 v Timer 3, trong Timer 2 thuc loi Timer B (typeB) v
Timer 3 thuc loi Timer C (type C)
S kin ngt Timer: 32-bit TIMER c kh nng to ra ngt khi gi tr ca Timer
bng vi mt gi tr nh trc c np vo thanh ghi 32 bit PR2/PR3 hoc khi pht
hin c c sn xung t cng tn hiu bn ngoi.Bit T3IF (IFS0) s c tc
ng v to ra ngt.Trong ch ny, T3IF c s dng nh l ngun to ngt v
bit T3IF phi c xo bng phn mm. Vic kch hot hot ng ca ngt c
thc hin thng qua bit T3IE
-
Thit k b nghch lu cho h thng UPS c kh nng kt ni li
SVTH: Nguyn Vn Chung Lp TB-T1-K51 54
Cc ch cho u ra v ch hot ng :
Single event mode
Edge-aligned mode
Center-aligned mode
Center-aligned mode with double updates
Complementary output mode
Independent output mode
b) Tng quan chung v module MCPWM2:
MCPWM2 cung cp cc ch Comlementary u ra ca PWM, iu ny th hu
dng trong cc trng hp sau :
Ngun PFC ( power factor correction)
iu khin ng c mt chiu.
c) M t cc thanh ghi ca Module PWM:
Di y l cc thanh ghi thng c dng iu khin qu trnh hot ng
ca b MCPWM1 v MCPWM2 :
Thanh ghi PxTCON : Thanh ghi ny dng cu hnh tn s xung Clock u
vo v tn s xung Clock u ra .
Thanh ghi PxTMR : Thanh ghi ny dng m, cho bit gi tr m tc
thi thng qua gi tr hin ti ca n.
Thanh ghi PxTPER : Vic np gi tr vo thanh ghi ny s quyt nh tn s
ca b PWM (fPWM) .
-
Thit k b nghch lu cho h thng UPS c kh nng kt ni li
SVTH: Nguyn Vn Chung Lp TB-T1-K51 55
Thanh ghi PxSECMP: Thanh ghi ny cung cp gi tr so snh vi
PxTMR, m ti s xy ra qu trnh chuyn i ADC ng b vi b PWM.
Thanh ghi PWMxCON1: y l thanh ghi nhm cu hnh ch
Independent hoc Comlementary u ra.
Thanh ghi PWMxCON2 : Thanh ghi ny cung cp cc chc nng di y :
- La chn gi tr np vo thanh ghi s kin c bit.
- La chn chc nng update tc thi.
- La chn ch update ng b.
Thanh ghi PxDTCON1: Thanh ghi ny gip cu hnh khong deadtime ph
hp vi yu cu mong mun
Cc thanh ghi cu hnh rng xung :
PxDC1: gi tr rng xung 16 bit ca cp 1 c vit vo thanh ghi ny.
PxDC2: gi tr rng xung 16 bit ca cp 2 c vit vo thanh ghi ny.
PxDC3: gi tr rng xung 16 bit ca cp 3 c vit vo thanh ghi ny.
PxDC4: gi tr rng xung 16 bit ca cp 4 c vit vo thanh ghi ny.
d) Tng quan chung v kin trc module MCPWM:
-
Thit k b nghch lu cho h thng UPS c kh nng kt ni li
SVTH: Nguyn Vn Chung Lp TB-T1-K51 56
Time Base
Input
Prescaler
1:1
1:4
1:16
1:64
Tcy
Zero Match
Period Match
PTMOD
Clock
Control
Logic
PWM
Period
Buffer
PWM
Period
Register
(PxTPER)
PWM
Timer
Register
(PxTPER)PTMR
Clock
0
PTMOD1
Period Compare
Zero DetectTimer
Direction
Control
UDIS (Immediate
Update Enable)
UDIS (Update Disable)
Gated
Duty
Cycle
Interrupt
Control
Time Base
Out put
Postscaler
1:1
1:4
1:16
Period Match
PTMOD
Gated Period Load
PWM
Interrupt Flag
(PWMxIF)
Hnh 4.8 Kin trc Module PWM
Nguyn l hot ng nh sau :
Thng qua b chia tn s u vo ta c th xc nh c tn s nui cho b
PWM l bao nhiu (c cc t l so vi tn s m lnh 1:1, 1:4, 1:16, 1:64).
Np gi tr vo thanh ghi PxTPER (nh ca xung tam gic) .
Xem thanh ghi PxTMR nh mt bin m (tng dn gi tr t 0 cho ti gi tr
np trong PxTPER).
Thng qua b so snh 2 gi tr PxTPER v PxTMR ta s bit lc no 2 gi tr
bng nhau. Khi 2 gi tr ny bng nhau th thanh ghi PxTMR s b Reset.
-
Thit k b nghch lu cho h thng UPS c kh nng kt ni li
SVTH: Nguyn Vn Chung Lp TB-T1-K51 57
ng thi ti thi im ny n s qua b AND (kt hp vi UDIS ) hi
xem c cho php update gi tr PxTPER mi hay khng.
C hai thi im cho php update gi tr PxTPER mi l ti lc nh v ti lc
bng khng (thng qua b so snh vi 0).
Khi thanh ghi PxTMR bng 0 n s i qua b Postscaler hi xem c cho
php ngt PWM hay khng.
e) Duty Cycle:
nh ngha : Duty Cycle (k hiu l d) l t s gia khong thi gian tch cc so
vi mt chu k ca PWM.
Module MCPWM c ti 4 ngun pht PWM. C 4 thanh ghi tng ng lin quan
ti vic pht PWM l cc thanh ghi PxDCy.
f) Ngun to Dead Time (Dead Time Generation):
Ngun to Dead Time c t ng khi to khi cc cng u ra PWM hot ng
ch b sung (Comlementary). C hai khong cn to Dead Time (ti sn ln
v sn xung ca mi xung).
PWM generator
Time selected by DTSxA bit (A or B) Time selected by DTSxI bit (A or B)
Dead time =0
None zero
Dead time
Hnh 4.9 Hnh v m t chn Dead Time
-
Thit k b nghch lu cho h thng UPS c kh nng kt ni li
SVTH: Nguyn Vn Chung Lp TB-T1-K51 58
PrescalerClock
Control
Zero Compare
6-bit Down Counter
Dead Time
Select Logic
Dead
Time A
Dead
Time B
TCYHigh-side PWM signal
to output pin
Low-side PWM signal
to output pin
PWM
Generator
Input
Hnh 4.10 S khi m t cu trc ca Dead Time
Nguyn l hot ng chung : t ngun pht xung PWM (PWM Generator Input)
ta s xc nh c sn ln v sn xung ca mi xung. Qua xc nh c v
tr Dead Time cn chn.
Cch cu hnh gi tr Dead Time vo chng trnh cho ph hp vi gi tr mong
mun trong thc t :
Qua b chia tn s u vo ta xc nh c tn s s dng cho b Dead Time
(cu hnh vo thanh ghi PxDTCON1) .
Xc nh gi tr cn np vo thanh ghi PxDTCON1bits.DTA hoc
PxDTCON1bits.DTB, da vo cng thc sau :
Pr . CY
DeadTimeDT
escaleValueT
Trong : TCY l tn s m lnh; PrescaleValue l t s chia tn s.
DeadTime l thi gian cn to
-
Thit k b nghch lu cho h thng UPS c kh nng kt ni li
SVTH: Nguyn Vn Chung Lp TB-T1-K51 59
V d : Ta mun to DeadTime c thi gian l 1 s
Vi PrescaleValue = 1 v TCY = 10-6
/40
Theo cng thc trn ta c :
6
6
10 .4040
Pr . 1.10CY
deadtimeDT
escaleValueT
g) Special Event Trigger :
Module PWM c b Special Event Trigger cho php chuyn i ADC ng b
vi PWM. V thun li ca n l c th cho php chuyn i ADC ti bt k khong
no ca PWM.
Nguyn tc hot ng c th m t bng s sau :
-
Thit k b nghch lu cho h thng UPS c kh nng kt ni li
SVTH: Nguyn Vn Chung Lp TB-T1-K51 60
REGISTER
PxTCON
PxTCONPWMxCON1
PWMxCON2
PxDTCON1
PxDTCON2
PxFLTACON
PxFLTBCON
PxPOVDCON
16-B
it D
AT
A B
US
PWM Time Base Control
PWM Enable and Mode Selection
PWM Deadtime Control
Fault Pin Control
Manual Override
Control
PWM Duty Cycle
Driver
External Fault
Signals
PWMxHy
PWMxLy
PWM Output
PWM Timer
Reset/Count Output
SEVTDIR
PTDIR
Special Event
Trigger for A/D
Conversions
Special
Event
Trigger
Postscaler
1:1
.
.
.
1:16
Dead time
Generator
and
Override
Control
PxTPER Buffer
PxTMR
PxDCy Buffer PxDCy Register
FLTxA
FLTxB
PxTPER Register
PxSECMP
Hnh 4.11 S nguyn l ca b Special Event Trigger
Gii thch nguyn l:
Np gi tr m ti cho php xy ra Special Event Trigger vo thanh ghi
PxSECMP. Thng qua bin m PxTMR ta s bit c gi tr hin ti ca b
PWM.
-
Thit k b nghch lu cho h thng UPS c kh nng kt ni li
SVTH: Nguyn Vn Chung Lp TB-T1-K51 61
Khi gi tr PxTMR bng vi gi tr trong thanh ghi PxSECMP (bit c thng
qua b so snh ) s pht ra tn hiu nhng tn hiu ny cho php xy ra Special
Event Trigger th yu cu n phi tha mn 2 yu cu sau :
Ta mong mun xy ra Special Event Trigger l sn ln hay sn xung bng
cch cu hnh cho n thng qua bit SEVTDIR .
Xem xt trn iu kin va nu vi gi tr thc t thng qua bin ng PTDIR
h) Cch xc nh gi tr np vo thanh ghi PxTPER:
Tng ng vi cc dng sng tam gic mong mun ta c cc cng thc tnh ton
nh sau :
Gi tr chu k iu bin c np t thanh ghi m PxTPER
PxTPER
PxTMR
Hnh 4.12 Cp nht chu k PWM trong ch m t do(Free running mode)
Cch xc nh PxTPER: WM
1.( Pr escaler)
CY
P
FPxTPER
F PxTMR
V d : Fcy = 40 MHz, Fpwm = 10 kHz
PxTMR Prescaler = 1:4
-
Thit k b nghch lu cho h thng UPS c kh nng kt ni li
SVTH: Nguyn Vn Chung Lp TB-T1-K51 62
WM
400001 1 999
.( Pr escaler) 10.4
CY
P
FPxTPER
F PxTMR
Gi tr chu k iu bin c np t thanh ghi m PxTPER
PxTPER
PxTMR
Hnh 4.13 Cp nht chu k PWM trong ch m ln/xung (up/down count
mode)
Cch xc nh PxTPER: WM
1.( Pr escaler).2
CY
P
FPxTPER
F PxTMR
V d : Fcy = 40 MHz; Fpwm = 10 kHz
PxTMR Prescaler = 1:4
WM
400001 1 499
.( Pr escaler).2 10.4.2
CY
P
FPxTPER
F PxTMR
-
Thit k b nghch lu cho h thng UPS c kh nng kt ni li
SVTH: Nguyn Vn Chung Lp TB-T1-K51 63
Chng 5: TM HIU PHNG PHP HA NG B
5.1. Nhu cu ha ng b vo li
ng trc tnh trng thiu in nh hin nay, vic pht trin thm h thng
nhng ngun in mi l mt nhu cu ht sc cp bch.
Vn c cp y l: Lm th no c th ho chung in ca my
pht in vo li in, sao cho an ton, nhanh chng, tit kim. lm c
iu ny i hi phi o, kim tra s ng b in ca my pht v in ca li,
sao cho ti thi im ng my ct: lch in p, lch tn s, lch pha ca
hai h thng in ny phi nm trong gii hn cho php. Trong vic kim tra
lch pha c coi trng nht v nu in p v tn s bng nhau nhng li ngc
pha nhau th khng khc g hai vt th ang bay cng vn tc cng phng nhng
li ngc chiu lao vo nhau, trong h thng in s c ny cn nghim trng hn
c s c ngn mch.
Ha ng b vo li c ng dng nhiu trong cc h thng nng lng mi
nh pin mt tri, nng lng gi,...
5.2 Cc iu kin ha ng b
1. Tn s nghch lu to ra phi bng tn s li
2. in p to ra bng in p li
3. Trng pha vi li
5.3 Vng kha pha (Phase Locked Loop - PLL)
to ra sng sin ng pha vi li ta s dng mt vng kha pha (PLL)
5.3.1 Tng quan v vng kha pha
-
Thit k b nghch lu cho h thng UPS c kh nng kt ni li
SVTH: Nguyn Vn Chung Lp TB-T1-K51 64
Vng kho pha PLL l h thng vng kn hi tip, trong tn hiu hi tip
dng kho tn s v pha ca tn hiu ra theo tn s v pha tn hiu vo. Tn hiu
vo c th c dng tng t hnh sine hoc dng s. ng dng u tin ca PLL
vo nm 1932 trong vic tch sng ng b. Ngy nay, nh cng ngh tch hp cao
lm cho PLL c kch thc nh, tin cy cao, gi thnh r, d s dng. k thut
PLL c ng dng rng ri trong cc mch lc, tng hp tn s, iu ch v gii
iu ch, iu khin t ng v.v...
5.3.2 S khi
Hnh 5.1 S khi ca Vng kha pha
5.3.2.1 B tch sng pha (phase detector): so snh pha gia tn hiu vo v tn hiu
ra ca VCO to ra tn hiu sai lch
Hnh 5.2 Nguyn l hot ng b tch sng pha
B i tn (mch nhn) thc hin nhn hai tn hiu. Ng ra ca n c in p:
-
Thit k b nghch lu cho h thng UPS c kh nng kt ni li
SVTH: Nguyn Vn Chung Lp TB-T1-K51 65
Qua b lc thng thp LPF, ch cn thnh phn tn s thp. Khi kha pha
( i= 0) c Vd = Asin( i - 0). in p ny t l vi bin in p vo A v sai
pha e= i - 0. Nu e nh, hm truyn t ca b tch sng pha coi nh tuyn tnh.
5.3.2.2 Lc thng thp (Low pass filter): lc gn ca in p sai lch tr thnh
in p bin i chm
LPF thng l mch lc bc 1, tuy nhin cng dng bc cao hn trit thnh
phn AC theo yu cu. LPF c th dng mch th ng hay tch cc.
Hnh 5.3 Mch lc thng thp
Ng ra b tch sng pha gm nhiu thnh phn f0, fi, fi-f0, fi+f0, v.v... Sau LPF
ch cn thnh phn tn s rt thp (fi-f0) n b khuch i iu khin tn s
VCO bm theo fi. Sau vi vng iu khin hi tip PLL c ng b (kha pha)
fi=f0 (tc l fi-f0=0). Vng kha pha hot ng chnh xc khi tn s vo fi, f0 thp
khong vi trm KHz tr li.
5.3.2.3 VCO (Voltage Controlled Oscillator): L mch dao ng c tn s c
kim sot bng in p.
Yu cu chung ca mch VCO l quan h gia in p iu khin Vdk (t) v tn
s ra f0(t) phi tuyn tnh. Ngoi ra mch cn c n nh tn s cao, di bin i
ca tn s theo in p vo rng, n gin, d iu chnh v thun li cho vic t
hp thnh vi mch (khng c in cm).
-
Thit k b nghch lu cho h thng UPS c kh nng kt ni li
SVTH: Nguyn Vn Chung Lp TB-T1-K51 66
V nguyn tc c th dng mi mch dao ng l tn s dao ng c th bin
thin c trong phm vi t 10% n 50% xung quanh tn s dao ng t do.
Tuy nhin cc b dao ng to xung ch nht c s dng rng ri v loi ny c
th lm vic trong phm vi tn s kh rng (t 1MHz n khong 100MHz). Trong
phm vi t 1MHz n 50MHz thng dng cc mch dao ng a hi.
Hnh 5.4 Mch VCO tiu biu
5.3.2.4 N : b chia
Dng chia nh tn s fN to ra bi VCO sao cho bng vi tn s vo fi. Khi PLL
thc hin kho pha, th ta c fi = . Suy ra fN = fi.N = f0.N
5.3.3 Nguyn l hot ng
Vng kho pha hot ng theo nguyn tc vng iu khin m i lng vo v
ra l tn s v chng c so snh vi nhau v pha. Vng iu khin pha c nhim
-
Thit k b nghch lu cho h thng UPS c kh nng kt ni li
SVTH: Nguyn Vn Chung Lp TB-T1-K51 67
v pht hin v iu chnh nhng sai s nh v tn s gia tn hiu vo v ra. Ngha
l PLL lm cho tn s f0 ca tn hiu VCO bm theo tn s fi ca tn hiu vo.
Khi khng c tn hiu Vi ng vo, in p sau lc thng thp Vdc(t) =0, b dao
ng VCO hot ng tn s t nhin fN c ci t bi in tr, t in ngoi.
Khi c tn hiu vo Vi, b tch sng pha so snh pha v tn s ca tn hiu vo vi
tn hiu ra ca VCO. Ng ra b tch sng pha l in p sai lch Vd(t), ch s sai
bit v pha v tn s ca hai tn hiu. in p sai lch Vd(t) c lc ly thnh
phn bin i chm Vdc(t) nh b lc thng thp LPF, tn hiu ny cng chnh l
tn hiu iu khin Vdk(t) a n ng vo VCO, iu khin tn s VCO bm
theo tn s tn hiu vo. n khi tn s f0 ca VCO bng tn s fi ca tn hiu vo,
ta ni b VCO bt kp tn hiu vo. Lc by gi s sai lch gia 2 tn hiu ny
ch cn l s sai lch v pha m thi. B tch sng pha s tip tc so snh pha gia
2 tn hiu iu khin cho VCO hot ng sao cho s sai lch pha gia chng
gim n gi tr b nht.
5.3.4 Di bt v di kha
Di bt BC (Capture range): k hiu BC=f2- f1, l di tn s m tn hiu vo thay
i nhng PLL vn t c s kho pha, ngha l b VCO vn bt kp tn s tn
hiu vo. Ni cch khc, l di tn s m tn hiu vo ban u phi lt vo PLL
c th thit lp ch ng b (ch kha).
Hnh 5.5 Di bt v di kha ca PLL
-
Thit k b nghch lu cho h thng UPS c kh nng kt ni li
SVTH: Nguyn Vn Chung Lp TB-T1-K51 68
Gi s mch PLL t c ch kho, VCO ng b vi tn hiu vo.
By gi ta thay i tn s tn hiu vo theo hng ln hn tn s VCO th VCO s
bm theo. Tuy nhin khi tng n mt gi tr no th VCO s khng bm theo
c na v quay v tn s t nhin ban u ca n. Ta lm tng t nh trn
nhng thay i tn s tn hiu vo theo hng nh hn tn s VCO. n mt gi tr
no ca tn s tn hiu vo th VCO s khng bm theo c na v cng tr v
tn s t nhin ca n. Di gi tr tn s t thp nht n cao nht ca tn hiu
vo c gi l di kho. T ta nh ngha:
Di kha BL (Lock range): BL=fmax- fmin, l di tn s m PLL ng nht c
tn s f0 vi fi. Di ny cn gi l ng chnh (Tracking range). Cc tn s fmax, fmin
l tn s cc i v cc tiu m PLL thc hin c kha pha (ng b). Di kha
ph thuc hm truyn t ( li) ca b tch sng pha, khuch i, VCO. N
khng ph thuc vo p tuyn b lc LPF v khi PLL kha pha th fi- f0= 0.
Khi PLL cha kha pha th fi f0, khi PLL kha phath fi= f0. ch kha
pha, dao ng f0 ca VCO bm ng b theo fi trong di tn kha BL rng hn di
tn bt BC.
p ng ca vng PLL c tnh i xng, ngha l tn s t nhin ti trung tm
ca di kho v di bt.
5.3.5 Vng kha pha s dng IC4046
to mt mch kha pha, ta dng 1 IC cng l IC4046 (y l loi IC kh ph
bin, gi thnh r v c th mua d dng). Mch kha pha dng IC4046 l mch
gm 1 b VCO tuyn tnh v 2 b so snh pha
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Thit k b nghch lu cho h thng UPS c kh nng kt ni li
SVTH: Nguyn Vn Chung Lp TB-T1-K51 69
Hnh 5.6 S chc nng 4046
Cc in tr R1, R2 v t C1 to ra tn s f0 ca b VCO. Ta c th tnh gi
tr cc t in v in tr ny hoc c th tra ra t th.
y, to ra tn s fN = 50kHz ta tra th sau tm ra gi tr in tr v t
in ph hp:
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Thit k b nghch lu cho h thng UPS c kh nng kt ni li
SVTH: Nguyn Vn Chung Lp TB-T1-K51 70
Hnh 5.7 th tn s trung tm fN vi R2 =
T th ta tra ra c R1 = 100k , R2 = , C1= 200pF
f0 = fi = 50Hz th ta cn c b chia vi N = 1000, ta c th dng 3
IC4017(chia 10) mc ni tip.
Tnh ton b lc thng thp:
B lc thng thp dng ct b cc tn s cao fi, f0,...
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Thit k b nghch lu cho h thng UPS c kh nng kt ni li
SVTH: Nguyn Vn Chung Lp TB-T1-K51 71
Tn s ct c tnh nh sau:
fc =
Chn fc = 5Hz, C2 = 1 F => R3 = 31,8k => Ly R3 = 33k
Vy s mch PLL vi IC4046 nh sau:
Hnh 5.8 Mch PLL vi IC4046
Sng sin 50Hz t li c a vo chn 14 ca IC4046 qua 1 op-apm. T C1
v R1 to ra tn s 50kHz chn 4, qua 3 IC chia 4017 s c tn s 50Hz a v
chn 3 so snh vi sng sin chun ca li. Xung 50Hz v 50kHz c ly ra a
vo dsPIC (nh s ).
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Thit k b nghch lu cho h thng UPS c kh nng kt ni li
SVTH: Nguyn Vn Chung Lp TB-T1-K51 72
Hnh 5.9 ng pha gia 2 xung 50Hz ti chn 3 v chn 14
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Thit k b nghch lu cho h thng UPS c kh nng kt ni li
SVTH: Nguyn Vn Chung Lp TB-T1-K51 73
Chng 6: M HNH V KT QU O C
Hnh 6.1 Phn mch iu khin
Hnh 6.2 Phn mch lc
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Thit k b nghch lu cho h thng UPS c kh nng kt ni li
SVTH: Nguyn Vn Chung Lp TB-T1-K51 74
Hnh 6.3 Dng in p u ra
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Thit k b nghch lu cho h thng UPS c kh nng kt ni li
SVTH: Nguyn Vn Chung Lp TB-T1-K51 75
KT LUN
Qua mt thi gian nghin cu v thit k b nghch lu c th nhn thy tnh kh
thi trong vic ng dng vo thc t. Vic ch to th nghim b nghch lu t
c mt s kt qu nht nh.
Nhng kt qu c th t c trong n ca em nh sau:
- Xy dng m hnh tnh ton i tng
- Xy dng b iu khin PD
- M phng trn Matlab/Simulink
- iu ch ra sng sin chun
- Xy dng vng kho pha
Hng pht trin ca ti:
- Hon chnh vng phn hi ho ng b
- Nng cao hiu sut b nghch lu
- Nghin cu th nghim b nghch lu 3 pha.
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Thit k b nghch lu cho h thng UPS c kh nng kt ni li
SVTH: Nguyn Vn Chung Lp TB-T1-K51 76
PH LC 1: CHNG TRNH VIT CHO VI IU
KHIN
/*----------------------------------------------------------------------------------------------------------------------------------------*/
// DO AN TOT NGHIEP //
//-----------------------------------------------------------------------------------------------------------------------------------------//
// De tai: Thiet ke bo nghich luu cho he thong UPS c kha nang ket noi luoi //
//-----------------------------------------------------------------------------------------------------------------------------------------//
// Giang vien huong dan : Ths Hoang Anh //
// Dong huong dan : Ths Nguyen Thanh Khang //
// Sinh vien thuc hien : Nguyen Van Chung //
// Lop : Thiet bi dien Dien tu 1 - K51 DHBKHN //
/*----------------------------------------------------------------------------------------------------------------------------------------*/
#include
_FOSCSEL(FNOSC_PRIPLL&IESO_OFF); //dung dao dong ngoai co bo PLL
_FOSC(FCKSM_CSDCMD&OSCIOFNC_OFF&POSCMD_XT); //chon che do XT
_FWDT(FWDTEN_OFF); //tat watchdog
_FPOR(PWMPIN_ON & HPOL_OFF & LPOL_OFF); // cac chan ra dieu khien boi PORT luc reset deu co the cao
//------------------------------------------------------------------------------
//Cac hang so cua chuong trinh (gia tri tuc thoi dung trong chuong trinh)
#define Fcy 40000000 //Tan so thuc thi lenh Fcy = 40 MHz
#define Fpwm 10000 //Tan so PWM = 10 kHz
#define TS 499
//Cac prototype cho cac chuong trinh con
void Init_PORTS(void);
void Init_MCPWM(void);
void Init_ADC10(void);
void Read_ADC (void);
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Thit k b nghch lu cho h thng UPS c kh nng kt ni li
SVTH: Nguyn Vn Chung Lp TB-T1-K51 77
//bien toan cuc
float V, vmax, hs, e1, voffset, kp, kd, vref, vadc, v1, vph, vthuc, e, p, d, u, edel;
unsigned int i=0;
float const sin_table[200] = {0, 0.0314, 0.0628, 0.0941, 0.1253, 0.1564, 0.1874, 0.2181, 0.2487, 0.279, 0.309,
0.3387, 0.3681, 0.3971, 0.4258, 0.454, 0.4818, 0.509, 0.5358, 0.5621, 0.5878, 0.6129, 0.6374, 0.6613, 0.6845,
0.7071, 0.729, 0.7501, 0.7705, 0.7902, 0.809, 0.8271, 0.8443, 0.8607, 0.8763, 0.891, 0.9048, 0.9178, 0.9298, 0.9409,
0.9511, 0.9603, 0.9686, 0.9759, 0.9823, 0.9877, 0.9921, 0.9956, 0.998, 0.9995, 1, 0.9995, 0.998,0.9956, 0.9921,
0.9877, 0.9823, 0.9759, 0.9686, 0.9603, 0.9511, 0.9409, 0.9298, 0.9178, 0.9048, 0.891, 0.8763, 0.8607, 0.8443,
0.8271, 0.809, 0.7902, 0.7705, 0.7501, 0.729, 0.7071, 0.6845, 0.6613, 0.6374, 0.6129, 0.5878, 0.5621, 0.5358,
0.509, 0.4818, 0.454, 0.4258, 0.3971, 0.3681, 0.3387, 0.309, 0.279, 0.2487, 0.2181, 0.1874, 0.1564, 0.1253, 0.0941,
0.0628, 0.0314, 0, -0.0314, -0.0628, -0.0941, -0.1253, -0.1564, -0.1874, -0.2181, -0.2487, -0.279, -0.309, -0.3387, -0.3681, -0.3971, -0.4258, -0.454, -0.4818, -0.509, -0.5358, -0.5621, -0.5878, -0.6129, -0.6374, -0.6613, -0.6845, -
0.7071, -0.729, -0.7501, -0.7705, -0.7902, -0.809, -0.8271, -0.8443, -0.8607, -0.8763, -0.891, -0.9048, -0.9178, -
0.9298, -0.9409, -0.9511, -0.9603, -0.9686, -0.9759, -0.9823, -0.9877, -0.9921, -0.9956, -0.998, -0.9995, -1, -0.9995,
-0.998, -0.9956, -0.9921, -0.9877, -0.9823, -0.9759, -0.9686, -0.9603, -0.9511, -0.9409, -0.9298, -0.9178, -0.9048, -
0.891, -0.8763, -0.8607, -0.8443, -0.8271, -0.809, -0.7902, -0.7705, -0.7501, -0.729, -0.7071, -0.6845, -0.6613, -
0.6374, -0.6129, -0.5878, -0.5621, -0.5358, -0.509, -0.4818, -0.454, -0.4258, -0.3971, -0.3681, -0.3387, -0.309,-
0.279, -0.2487, -0.2181, -0.1874, -0.1564, -0.1253, -0.0941, -0.0628, -0.0314};
//------------------------------------------------------------------------------
//Chuong trinh chinh
int main(void)
{
V=220;
vmax=V*1.41;
hs=3.6;
e1=0;
voffset =1.65;
kp= 1.85217285;
kd= 1473.91;
PLLFBD=41; // M=43
CLKDIVbits.PLLPOST=0; // N1=2
CLKDIVbits.PLLPRE=0; // N2=2
while (_COSC !=0b011); //dung bo PLL tao Fosc=80MHz,cho `cho dao dong on dinh
while (_LOCK !=1); //Cho PLL bat dau khoa pha
Init_PORTS(); //Khoi tao cac cong I/O
Init_MCPWM(); //Khoi tao module PWM
Init_ADC10(); //Khoi tao module ADC
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Thit k b nghch lu cho h thng UPS c kh nng kt ni li
SVTH: Nguyn Vn Chung Lp TB-T1-K51 78
Read_ADC();
while (1);
}
//Chuong trinh con khoi tao cac cong I/O, de xuat cac tin hieu PWM, va doc tin hieu dieu chinh cua bien tro
tai AN0
void Init_PORTS(void)
{
TRISB = 0xFFC0; //Cac tin hieu PWM nam tai RB10..RB15
TRISA = 0x0001; //Chan RA0 la ngo vao analog AN0, cac chan khac la ngo ra
}
//Chuong trinh con khoi tao module PWM
void Init_MCPWM(void)
{
P1TCONbits.PTMOD=0b10; //Che do Continous up/down count
P1TCONbits.PTOPS=0; //Postscale 1:1
P1TCONbits.PTCKPS=0b01; //Prescale 4TCY
P1TPER = TS; //Tan so PWM = 10 kHz
//P1TPER=Fcy/(Fpwm*(2*PxTMR Prescaler))-1
//P1TPER=40*10^6/((10*10^3)*2*4)-1=499
PWM1CON1bits.PEN1L = 1; //khoi tao cac chan PWM
PWM1CON1bits.PEN2L = 1;
PWM1CON1bits.PEN1H = 1;
PWM1CON1bits.PEN2H = 1;
P1OVDCON = 0xFF00; //Khong dung overdrive
P1DTCON1bits.DTAPS=0; //Dead time prescale 1:1
P1DTCON1bits.DTA=40; // DT = (Dead time)/(Prescale Value*Tcy)
// Dead time = 1us, Prescale Value = 1, Tcy = 1/(40*10^6)
// DT = (1*10^-6)/(1*1/(40*10^6)) = 40
P1DC1 = 0; //Khoi tao PWM1
P1DC2 = 0;
P1TCONbits.PTEN = 1; //Kich hoat module PWM
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Thit k b nghch lu cho h thng UPS c kh nng kt ni li
SVTH: Nguyn Vn Chung Lp TB-T1-K51 79
}
//Chuong trinh con khoi tao module chuyen doi A/D, doc ngo vao AN0
void Init_ADC10(void)
{
AD1PCFGL = 0xFFFE; //Cac chan khac la digital, chan AN0/RA0 la analog
AD1CON1bits.SAMP = 1;
AD1CON1bits.ASAM = 1; // lay mau ngay lap tuc sau chuyen doi cuoi
AD1CON1bits.SSRC = 0b011; //Module PWM cham dut lay mau va kich hoat viec chuyen
// i A/D
AD1CHS0 = 0; //Kenh 0 doc tin hieu giua AN0 va AVss
AD1CSSL = 0; //Khong quet cac ngo vao
AD1CON3bits.SAMC = 0b00001; //Dung 1 TAD cho lay mau
AD1CON3bits.ADCS = 0x03; // TAD = 4*Tcy = 100 ns
_AD1IF = 0;
_AD1IE = 1;
AD1CON1bits.ADON = 1;
}
void Read_ADC (void)
{
while(_DONE == 0); //cho chuyen doi xong
}
void __attribute__((interrupt,auto_psv)) _ADC1Interrupt(void)
{
vref = sin_table[i];
vadc= ADC1BUF0;
v1=vadc*0.003258;
vph=v1-voffset;
vthuc=vph*hs;
e=vref-vthuc;
edel=e-e1;
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Thit k b nghch lu cho h thng UPS c kh nng kt ni li
SVTH: Nguyn Vn Chung Lp TB-T1-K51 80
p=kp*e;
d=kd*edel;
u=p+d;
e1=e;
i++;
if (i == 200) i=0;
if (u>=1){u=1;}
if(u
-
Thit k b nghch lu cho h thng UPS c kh nng kt ni li
SVTH: Nguyn Vn Chung Lp TB-T1-K51 81
PH LC 2: TI LIU THAM KHO
1. in t cng sut L thuyt- Thit k- ng dng
Tc gi: L Vn Doanh, Nguyn Th Cng, Trn Vn ThnhNXB Khoa hc k
thut H Ni.
2. L thuyt iu khin tuyn tnh
Tc Gi: Nguyn Don Phc.
3. Refference Manual of dsPIC33FJ12MC202
4. Datasheet of dsPIC33FJ12MC202
5. Digital Control Power Electronics
Tc Gi: Simone Buso v Paolo Mattavelli
6. Transformer and inductor design handbook
Tc gi: Colonel Wm. T. McLyman
Mt s trang web:
http://thietbidien.vn
http://www.microchip.com
http://www.dientuvietnam.net
http://www.picvietnam.net
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