M U . Ngy nay nng lng in tr thnh ngun nng lng chnh ca nn sn xut
hin i . Cui th k 19 in nng c a xung tu thu . u tin n c s dng vo vic
chiu sng v qut gi lm mt phc v nhu cu sinh hot ca thu th thuyn vin t
cc c qui v my pht in 1 chiu cng sut nh.Dn dn n c ng dng trong cc h
thng bm qut gi ,my nn , cc h thng ti qun dy, ti li , neo , my li
....C nh vy vic ng dng nng lng in trn tu ngy cng c hin i hov pht
trin vi tc ngy cng nhanh trn cc i tu th gii. Trn tu thu cc h truyn
ng in ng 1 vai tr ht sc quan trng so vi cc loi truyn ng khc . Vic
in kh ho , t ng ho trn cc con tu l ht sc cn thit . Thnh phn cc loi
ph ti in khng ngng ngy cng nng cao m rng v chng loi cng nh v cng
sut .Do vy n i hi cng sut ca trm pht cng ngy cng tng ln. Ngy nay cc
h thng in nng trn tu thu khng ngng c pht trin v hon thin .T vic t
ng ho tng phn trm pht in v cc h thng iu khin gim st trn tu cng khng
ngng pht trin .Cc h thng iu khin c ng dng cng ngh hin i : in t bn
dn , vi x l , cc b logo , cc b kh lp trnh PLC ... Ngoi ra mt s h
thng cn c kt ni gim st mng internet , iu khin khng dy... Trong qu
trnh bin son bi ging chi tit cho mn hc trm pht in ny chc khng trnh
khi cc sai st mong cc bn gp kin b xung cho bi ging c y v hon thin
hn.
CHNG 1:
MY PHT IN TU THU 1.1. My pht in mt chiuI)Phn loi my pht in 1
chiu. Gm c 3 loi my pht 1 chiu chnh sau: + My pht 1 chiu kch t c lp
hoc song song. + My pht 1 chiu kch t ni tip. + My pht 1 chiu kch t
hn hp. * Ghi ch : Trong 3 loi my pht 1 chiu trn th ch c loi my pht
1 chiu kch t hn hp l hay c s dng lm my pht trong cc trm pht in 1
chiu l chnh cn cc loi my pht 1 chiu khc ch s dng trong cc trng hp c
bit. II) Cc thng s chnh ca my pht 1 chiu. My pht in mt chiu c xc nh
bng cc thng s c bn sau:
- Tc quay nh mc : n dm (vng /pht ) - Cng dng kch t: I kt - Cng
dng ti: Itin p trn tr u dy: U
4
Cng sut ln nht ca my pht in mt chiu c ch to khng vt qu 10MW, v
in p nh mc thng l 120V, 220V, 440V, 500V v 1000V. Khe kh ca my pht
in mt chiu thng tng i ln c th t ti mt vi mm (i vi cc t chnh) v mt
vi cm (i vi cc ph). Cc tnh cht ca my pht in mt chiu c xc nh nh cc c
tnh v cc c tnh li c xc nh nh cc thng s gii thiu trn. My pht in mt
chiu cng tc vi tc khng i, l thng s t pha ngoi tc ng, nn tt c cc c
tnh ca my pht mt chiu c thc hin vi n=const. III)Cc c tnh c bn ca my
pht in mt chiu l:
1) c tnh khng ti: E = f(Ikt) vi I = const, n= const 2) c tnh
ngoi: U = f(I) vi Ikt = const, v n = const 3) c tnh iu chnh . I kt
= f( It ) Khi n = const , U = const .IV). My pht mt chiu kch t song
song
+ _I A I D I B H I G bF kt I t
R kt q I C
t
Hnh 1.1. S nguyn l my pht kch t song song. * Cc iu kin t kch
thch ca my pht mt chiu: - My pht c t d m bo ln. - Chiu quay ca my
pht phi ng chiu. nf = nm. - Cun kch t phi c u ng cc. - Mch kch t
phi m bo kn mch. - in tr mch kch t phi nh hn in tr ti hn. T s my
pht ta c: eo Up = URkt + UL = Rktikt + Lkt
dikt dt
5
* Cc phng trnh trong mch kch t. URkt = Rkt .Ikt = cIkt l ng thng
URkt i qua gc to Ta c: Eo = f(Ikt) = Rkt .Ikt + Lkt
di kt dt dikt = 0 v lc y dt
Qu trnh t kch ko di cho n khi eo = URkt v UL = Lkt
di kt =0 dt
- Nu ta tng Rkt ln hn th c tnh URkt = f(Ikt) cng dc hn v in p
trn tr ra ca my pht s cc im 1, 2, 3, 3, 4 tng ng vi Rkt ta chnh. c
tnh ngoi ca my pht kch t song song l mi quan h gia in p trn tr u dy
ca my pht v dng ti I (ch khng phi dng chy trong phn ng) v: I = (Ip
- Ikt) U = f(I) vi Rkt = const; n = const. y ta khng vit Ikt =
const v khi nhn ti U gim nn Ikt ca my pht cng gim mc d Rkt vn khng
i. S thay i in p ca my pht kch t song song.U U1 U2 U3 URkt = f(I
)kt R 2 3 U U o U o U1 U f(I) vi n = R = const k = const t U 2 U3 U
5 U3 3' U ' 4 4 Er 0 U 6 I UT Ut= 0 0 Iz IT I1 I6 I2 =I m I = t I 5
3 I 41 I I =I max U 4
Rktth
RE Rkt1
n2 < n1
60 I 0 I
Hnh 1.4. H c tnh ngoi a) Vi cc gi tr khc nhau in tr mch kch t,
b) Khc nhau v tc
U o U dm . 100% ln hn nhiu so vi s thay i in p ca my pht kch t c
lp. S Udm thay i in p t ti 15% n 25% v thm ch cn ti n 30%. Nguyn
nhn c bn l do tc ng ca s thay i dng kch t.
u =
V ) My pht mt chiu kch t hn hp - L my pht mt chiu t kch, c hai
cun kch t, cun kch t ni tip v cun kch t song song. Hai cun kch t ny
ta c th u sc t ng (st) ca chng sinh ra cng chiu vi nhau hoc ngc
chiu vi nhau. Trng hp khi u hai cun kch t cho st cng chiu vi nhau
ta s nhn c c tnh ngoi c dng nh hnh . v khi u hai cun kch t cho st
ngc chiu nhau ta s nhn c c tnh ngoi c dng nh hnh.. : a) R kt t n B
H I D Iw S C q F I t I E b) U U = vi n = const f(I) R = const wo R
wS2 const = u thun hai cun kch t My pht kch t song song
+ _ I A It
t 0 HnhG 1.10. My pht c hai cun kch t u thun nhau.
I
Hnh v 1.5
Hnh v : 1.6
Trng hp nh hnh 1.10 in p my pht rt t thay i ph thuc vo dng ti ca
my pht v c th cn tng ln cng vi s gia tng ti. Nh vy s thay i in p ca
my pht c th bng 0 hoc thm ch cn m trong qu trnh my pht nhn ti. Trng
hp nh hnh s thay i in p ca my pht qu ln, cn ln hn c s thay i in p
ca my pht kch t song song. tin so snh s thay i in p ca cc loi my
pht mt chiu ta hy v cc c tnh ngoi ca chng trn cng h trc to nh hnh
di.
7
Qua cc nhn xt trn ta thy s n nh in p ca my pht mt chiu kch t hn
hp l rt tt, p ng c yu cu n nh in p do ng kim quy nh v ph hp vi iu
kin cng tc trn tu thu. Do vy my pht mt chiu kch t hn hp l loi my
pht duy nht trang b cho cc trm pht mt chiu trn tu thy. + _ I A It n
B H G I b D I kt a) R kt t S q I E I t b) U U = vi n = const f(I) R
wb const = R wS2 const = u ngc My pht kch t song song
C F
0
I
Hnh 1.7. My pht kch t c hai cun kch t u ngc nhau
2 1 1
4 1- My pht kch t c lp
3- Hn hp u thun 3 5- My pht kch t ni tip 5 Hnh 1.12. So snh c
tnh ngoi ca cc my pht mt chiu.
0Hnh v : 1.8
I 1
1.2. My pht in ng b ba pha1. Khi nim chung - Hu nh trn tt c cc
trm pht in tu thu dng xoay chiu u c lp t my pht ng b ba pha. - My
pht ng b l loi my m phn cm (phn kch t) c cp dng mt chiu. Cn phn ng
c t trng quay vi tc ng bng tc quay ca t trng kch t.
8
- My pht ng b c cc loi 3 pha hoc mt pha. in p c t thp nht t 6V n
20KV. Vai tr phn ng v phn cm c th thay i nm phn quay hay phn tnh.
Cng sut mch kch t nh, thng khng vt qu 1% cng sut nh mc my. in p mch
kch t khong t 100V 300V. - Trn tu thu hin nay thng dng 2 loi my pht
in xoay chiu ng b 3 pha l : + My pht ng b xoay chiu c chi than + My
pht ng b xoay chiu khng chi than 2)Loi my pht c chi than : * Cu trc
:
a)
R S T
b)
R S T
+1 3 4 5 2
_ + _5 6 1 4 3
2
Hnh 1.13. S nguyn l my pht.
a) My pht ng b c cp dng kch t t b) My pht ng b c phn ng rto my
kch t c phn ng stato 1- Phn ng (rto); 2- Cun kch t 1- Phn ng
(stato); 2- Cun kch t; 3- Vnh (stato); 3- Vnh trt; 4- Chi than;
5trt; 4- Chi than; 5- My kch t; 6- iu My kch t chnh in p my kch t.
Hnh v :1.9 * Cc loi tn hao trong my pht ng b gm: - Tn hao c kh (ma
st + qut gi) Pm (1 1,5)%Pm - Tn hao trong li thp: PFe (0,5 1)%Pm -
Tn hao trong cun phn ng: PCu (0,3 0,8)%Pm - Tn hao kch t: Pkt 0,3%
Pm Bng nh mc ca my pht ng b thng cho cc thng s sau: - in p nh mc ca
my pht: Um(V) - Cng sut biu kin nh mc: Sm (hoc Pm)(KVA) - Dng nh
mc: Im(A) - Tn s nh mc: fm(Hz) - H s cng sut nh mc: cos m - Dng kch
t nh mc: Iktm(A) - in p kch t nh mc: Uktm(V) - Tc quay nh mc:
nm(V/P) - Cch u cun dy phn ng v.v... Cng sut ca my pht ng b v my b
ng b thng cho bng cng sut biu kin (KVA) hay (MVA) nhm xc nh gii hn
ti xut pht t vn pht nhit ca cun dy phn ng. Nu trn bng nh mc my pht
ngi ra cho rng cng sut P (KW hay MW) th c ngha xut pht t s gii hn
cng sut ca ng c s cp.
9
Vn pht nhit ca my pht khng phi do h s cng sut quyt nh. Nhng cn
thit phi cho h s cos m v l do xc nh gii hn dng kch t ca my pht. V
d: Cho cos m = 0,8. C ngha l nu my pht chu ti vi I m m lc cos <
cos m l iu khng cho php v lc h thng t ng iu chnh in p s phi iu chnh
cho I kt > Iktm mi c th gi n nh in p ca my pht. My pht ng b c
phn loi nh sau: - My pht ng b cc hin bo ha. - My pht ng b cc n bo
ho. - My pht ng b cc n khng bo ha. Tt c cc my pht c lp t trong trm
pht in tu thu dng xoay chiu 3 pha u l cc my pht khng bo ha. Cn cc
my bo ha ch s dng v d nh my pht tc v.v... My pht ng b khng bo ha cc
hin ch dng vi nhng my diesel thp tc. Cn my khng bo ho cc n th thng
dng vi cc loi diesel cao tc hoc cc loi tuc bin ... 3). My pht ng b
khng chi than . a) Nhng vn c bn v my pht in xoay chiu khng chi than
. Ngy nay my pht in ng b khng chi than v ang c trang b hu ht trn cc
i tu bin. Loi my ny c kch thc v trng lng rt gn nh, hot ng tin cy v
n nh . Mt khc, do khng c chi than nn gim thiu v yu cu v sinh, bo
dng v sa cha v t b hng hc * Nhng i lng v thng s nh mc ca cc my pht
in . My pht in ng b ni chung, v my pht in ng b tu thu ni ring thng
khi xut xng nh ch to bao gi cng cp cho ngi s dng cc i lng v thng s
c ghi trn katalog (l lch my). Cc i lng ny c ngha rt quan trng trong
qu trnh vn hnh v khai thc ca my. Hn na cc thng s ny cn gip cho ngi
vn hnh thun tin kim tra cc thng s ca my khi sa cha, khc phc s c. -
Hng sn xut: - Cng sut nh mc - in p nh mc - Dng in nh mc - Tn s nh
mc - H s cng sut nh mc - Dng kch t nh mc - in p kch t nh mc - Vng
quay nh mc - Nhit lm vic - Cp cch in: : Cos : Pm {W, KW}. : Um {V,
KV}. : Im {A, KA}. : fm {Hz}.
m
.
: Iktm (A). : Uktm (V). : nm {v/ph}. : ( 0C ).
10
* Cc thng s ca my pht chnh c th trn 1 tu . Tu M Hng gm hai my
pht in ng b khng chi than do hng TAIYO sn xut. c b tr hai bn mn tu
v t ti bung my thun tin trong qu trnh vn hnh v khai thc. Hai my pht
c cng series vi cc thng s nh sau: - Hng sn xut : TAIYO ELECTRIC
CO.LTD. - Um = 440 (V). - Im = 385 (A). - Pm = 240 (KW). -S = 300
(KVA). - nm = 900 (V/P). - fm - Cos m - S pha - Cp cch in = 60
(HZ). = 0,8. : 3 pha. : cp F.
* Thng s ca my pht s c. - Hng sn xut: TAIYO ELECTRIC CO.LTD. -
Um - Im -P -S - nm - fm - cos m
= 220 (V). = 36,3 (A). = 8 (KW). = 10 (KVA). = 1800 (V/P). = 60
(HZ). = 0,8. : 3 pha. : Cp F.
- S pha - Cp cch in
b) Cu to ca my pht in ng b khng chi than . * Cu trc chung my pht
in ng b khng chi than. 1) Phn tnh ( STATOR) + Phn mch t: c ghp bi
cc l thp k thut in dng hnh tr rng . + Cun dy : Bn trong phn mch t c
phay cc rnh t cun dy 3 pha phn ng . Ngoi ra trn STATOR ca my pht
khng chi than cn c cun dy kch t ca my pht kch t ( L phn cm ca my
pht kch t). 2) Phn quay(ROTOR): gm c cc phn chnh sau: + Phn mch t:
c ghp bi cc l thp k thut in. + Phn cun dy kch t cho my pht chnh (
cn gi l phn cm)
11
+ Phn it quay : c 6 i t . + Cun dy 3 pha ca my pht kch t ( Cn c
gi l phn ng ca my pht kch t F )
Hnh v.1. 10 : Cu trc chung my pht ng b khng chi than hng TAIYO.
- My pht ng b.(G) - My pht kch t xoay chiu.(F) - Cu chnh lu quay. -
Cun kch t tnh cp dng kch t cho my pht kch t. Trong my kch t xoay
chiu v b chnh lu quay c lp trn rotor ca my pht chnh. Tn hiu ra xoay
chiu ba pha ca my kch t c chnh lu thnh tn hiu mt chiu thng qua b
chnh lu quay cp cho cun kch t chnh my pht. c) Phng trnh in p ca my
pht xoay chiu ng b .
+)
E = 4,44. Kqd . f . W . kt n.P ( n : l tc quay , P l s cp cc )
60
Trong : Kqd l h s qun dy ca cun dy phn ng f l tn s ca my pht f
=
W l s vng dy ca cun dy phn ng kt l t thng kch t. Khi my pht khng
ti th : E = U0 . + Khi my pht mang ti : U=EI.Z Trong : Z = R + J X
.( R: l in tr thun ca cung dy phn ng my pht , X : l tr khng ca cun
dy phn ng my pht ), I : l dng in ti
1.3. My pht in ng b ba pha trn tu M Hng 12
1. Cu to chi tit my pht in ng b My pht in ng b khng chi than ca
hng TAIYO c lp t trn tu M Hng c cu trc gm cc b phn chnh sau: Khung
stator, cun dy stator, mch t rotor, cun dy kch t, tr , , my pht kch
t, b chnh lu quay v cc ph kin khc. a) Stator. - Staor c ch to t cc
tm thp hn vi nhau tng tnh chu lc v chng cc rung ng c hc, ngoi ra
khung Stator cn c to vnh c nh li st stator. Li st Stator c dp nh
hnh t cc tm thp l k thut in, c ph mt lp vt liu cch in (vecni), sau
xp li vi nhau sao cho cc lp trng kht ln nhau. Cui cng chng c p cht
vo cc khung v c c nh bng cc cht. - Cun dy Stator c lm bng ng, bn
ngoi c ph cch in v t vo cc rnh ca Stator cch in gia dy qun v li thp
l cc tm cch in. Khi cun dy c t vo cc rnh Stator v c nm cht bng cc
nm ch to t vt liu cch in (nh : g php hay cc loi vt liu cch in khc).
Cui cng chng c tm, ph sn cch in m bo ng yu cu k thut. b)Rotor. -
Mch t rotor cng c lm t cc l thp silic c c tnh t ho rt tt, c phun
vecni cch in v c kha rnh mt trong lp vi trc. Trn mi tm thp u c to
nhng l c tc dng lm mt bng khng kh, ngoi ra cn c to rnh ( chu vi
ngoi) t cc cun dy. Tt c cc tm thp c p cht vi nhau v lp vo trc, sau
c cht gia hai u bng cc cht c bit. - Dy qun ca rotor c lm bng ng,
cng loi vi dy qun Stator v c t vo cc rnh ca mch t Rotor vi cc tm lt
cch in. Pha ngoi cun dy c ph vecni cch in. - Trc rotor c lm bng thp
hp kim c bn c hc cao. Trn trc rotor c lp b chnh lu quay, t v pha u
my kch t tin cho vic kim tra v sa cha. B chnh lu t trn hai vng tn
nhit, trn cn c mt b varistor c tc dng bo v cho b chnh lu. Ngun cp
cho b chnh lu ny c ly t my pht kch t, dng sau chnh lu l dng mt chiu
cp cho cun kch t ca my pht chnh. c) V my - V my c lm t nhng vt liu
c bn c hc cao v c ch to thnh hnh tr c nh li st stator. Pha u v my c
thit k hai ca s lm mt cho my khi vn hnh, ngoi ra cn thun tin trong
qu trnh kim tra v bo dng my pht. Mt khc v my cn lm nhim v bo v my v
t trn gi , c thit k bn c hc, chu c s rung lc khi lm vic. d) My pht
kch t. -My pht kch t l loi c phn ng quay v c b tr trn trc ca my pht
chnh. - My pht kch t gm cc phn t c bn sau: + Khung stator, li t,
cun dy kch t, li thp phn ng, cun dy phn ng. + Stato ca my kch
t.
13
- Khung staor l hp kim gang v thp c c thnh nhng tm sau c hn vi
nhau m bo c sc bn v cng hp l. Li Stator c lm t cc tm thp mng c c
tnh t ho tt xp li vi nhau v c t vo khung Stator. Mt trong ca li
Stator c ch to thnh rnh t dy qun khi lt cch in (dy qun cng loi vi
dy qun ca Stator my pht chnh) sau cc u dy cn li c b cht vi nhau.
Cun dy trn Stator ca my pht kch t c t cun dy kch t (Phn cm). * Roto
ca my pht kch t. - y l phn ng ca my pht kch t. N c ch to t cc tm
thp silic c cht lng cao c ph vecni cch in v c khoan l lm mt. Cc l
thp c p cht vi nhau v c c nh trn trc ca my pht chnh. - Cun dy phn
ng c lm bng ng v cng loi vi cun dy phn ng ca my pht chnh. Cun dy c
c nh trong cc rnh bng cc nm ch to t vt liu cch in, cc u dy c b cht
trnh tc dng ca lc ly tm. - u ra ca cun dy phn ng my pht kch t c ni
qua cu chnh lu 3 pha quay r to ca my pht .Tn hiu ra cu chnh lu quay
c cp trc tip cho cun dy kch t chnh ca my pht . ( Nh hnh v) e) Thit
b sy. -Trong qu trnh vn hnh v khai thc bn thn my pht pht ra nhit gp
phn lm gim m ca my pht nhng khi my ngng hot ng my pht c th hp th kh
m t mi trng bn ngoi. Chnh v th s lm gim in tr cch in ca my pht dn
ti gy nn dng r trong qu trnh lm vic v c nguy c lp cch in b nh thng
khi c xung in p cao. V vy, trn my c trang mt thit b sy gi cho nhit
ca my pht ln hn nhit mi trng, lm tng in tr cch in m bo h thng hot
ng an ton v lm gim tr khng trong cc cun dy, m bo kh nng t kch tt. -
B sy c t ni thp nht ca khung my nng lng nhit d dng tun hon trong
my, phc v c hiu qu, bo v cun dy v cc phn t c lin quan n m. - Tn hiu
ngun iu khin cho mch sy l 220V c ly trc tip t mch cp ngun 220V
(60V/ S07) qua cc cu ch ch sn. Khi my pht ngng hot ng hoc trc khi a
cc t hp Diesel lai my pht vo hot ng, ngi ta phi tin hnh sy cho my
pht. Cng tc SHS (Space Heater Switch) cp ngun cho rle 188H (288H)
thng qua tip im thng ng 125B ca Aptomat ACB (Air Circuit Breaker)
cc tip im cp ngun cho mch sy hot ng, ng thi ng tip im ph 188H
(288H) S61, n OL (Orange lamp) sng bo mch sy ang hot ng.
14
Khi Aptomat chnh ng cp ngun cho li th rle 125B/S21 (125B/S22)
cng c in, rle ny hot ng m tip im 125B/S21 (125B/S22) lm cho rle
188H (288H) mt in, m tip im ct ngun sy ra khi mch v n OL tt bo mch
sy ngng hot ng. Hnh v 1.11 : Space Heater Circuit220V SOURCE S 07
60 V R T SH1 SH2 C2 F 15 3A S
SH3
C2 F 25 3A
1H6
188H
S6 1
S6 1
5 6
1 2
3 4 H 12
9
188 H 10 S 2F
5 6
1 2
3 4
H 11
2G 1
H 11
H 12
2G 2
H 21
H 22
H DPYC 2.5
H DPYC 2.5
H 21
S 2F
H 22
288 H 9
7 1 7 2
152BS21
7 1 72
2H6
SHS 11
SHS 21
252BS22
288 H 1 0
15
f) B lc khng kh lm mt my pht chnh. B lc khng kh lm mt c lp ca ht
gi lm mt nhm mc ch lm gim ti thiu lng bi bn xm nhp vo trong my. Do
lm gim lng tp cht c cc gc ho cht gy hi cho my trong qu trnh lm vic
v gi c s n nh lm vic cho my pht. g) H thng kch t. S nguyn l mch in
ca h thng kch t c m t trn hnh (H1.3)
F2EX
F1
CT
R S T RT
G
Si
AVR
Hnh v 1.12 : S mch kch t ca my pht. H thng kch t tnh bao gm cun
khng RT, bin dng CT. B chnh lu silic (Si), khi hiu chnh in p AVR. T
s (H1.3) ta thy : - B chnh lu quay c t trn trc ca my pht chnh v c
nhim v cp ngun mt chiu cho kch t F1 ca my pht chnh. - in p v dng in
xoay chiu c ly t u ra ca my pht chnh thng qua bin dng CT v cun khng
RT, hai tn hiu ny c cng vi nhau v c a ti cu chnh lu mt pha to thnh
tn hiu dng mt chiu sau c a ti b phn kch t F2 ca my pht kch t.
16
2. Nguyn l hot ng ca my pht trn tu M HNG .a) S tng th my pht v h
thng t ng iu chnh in p hng TAIYO nh hnh (H1. 4). AC GENERATOR &
EXCIETERH1 H2 ISP H1 H2
SWITCH BOARD
SPACE HEARTERK k
CTL l
R S TI
R S T CCT
R S T
GF1 S1 Si1
K k
L l
RTIAVR R1 S T 1 1 3A k l K2 l2
ACB AUX CONT K2 l2
3A
A B
AVR
Ex
4A
4A
x x
Si2RC
1 2 3
F2
S2
1
3
2
VR
Hnh v 1.13: S tng th My pht ng b khng chi than ca hng TAIYO.
Trong : G EX Si1 Si2 S1,2 F1 : My pht chnh. : My pht kch t. : B
chnh lu quay. : Cu chnh lu silic. : Hai b bo v xung cho cc b chnh
lu. : Cun kch t ca my pht chnh.
17
F2 CT RT VR AVR CCT SP
: Cun kch t ca my pht kch t. : Bin dng cp tn hiu dng cho mch phc
hp pha song song. : Cun khng cp tn hiu p cho mch phc hp. : Bin tr
hiu chnh in p. : Mch hiu chnh in p. : Bin dng cp cho mch hiu chnh.
: in tr sy cho my pht chnh.
b) Nguyn l hot ng ca my pht ng b khng chi than. Khi ng c s cp
lai rotor ca my pht chnh (ng c s cp trn tu thu thng l ng c Diesel)
chy vi tc n nh gi tr nh mc, do ban u my pht c t d nn in p my pht s
nhanh chng c thnh lp v tn hiu kch t ly t cu chnh lu Si2 c a ti cun
kch t F2 ca my pht kch t. T trng trong cun dy l t trng tnh nhng do
rotor ca my pht quay nn trong cun dy ba pha ca my pht kch t c sc in
ng v dng cm ng. Dng in xoay chiu ba pha ny c b chnh lu cu ba pha
Si1 chnh lu thnh dng mt chiu cung cp cho cun kch t chnh F 1 v t
trng ny quay nn cm ng trn cun dy ba pha ca my pht G nhng sc in ng
to ln in p trn cc ca my pht chnh. * c im my pht in hng TAIYO. - Kch
thc nh gn so vi my pht ca cc hng khc c cng cng sut. - Thit k cc b
phn v cc h thng hp l, tin s dng d khai thc, d kim tra sa cha v quan
st. - tin cy cao. - n gin, tin ch nhng cc ch s cht lng cao. - Nguyn
l xy dng khng qu phc tp m vn c ch s v cc yu cu k thut ph hp vi tu
thu. - a dng v cng ngh, kh nng thay th, lp ln cao ph hp vi tnh nng
v yu cu ca ng kim. - Mang tnh quc t cao. - c th Nht Bn r rt nh : gn
nh, hp l, tin ch v gi thnh r.
18
3. M hnh ton hc ca my pht ng b khng chi than. .1 H phng trnh ca
my pht ng b khng chi than : c vit h trc (d, q) gn lin vi t trng
quay v cc i lng tng i nh sau:
1 dd + .q b dt 1 dq uq = r.id + + .d b dt df uf = if + Tf dt ud
= r.iq +
(1) (2) (3) (4) (5) (6) (7) (8) (9) (10) (3.1)
0 = iD + TD0 = iQ + TQ
dd dt
dQ dt
d = if X d .id + iD
q = X q .iq + iQf = if D X d .id + g1.iD, D = iD d X d .id + g 2
.if Q = iQ + q X q .iq
Trong : ud, uq
: in p stator theo dc trc v ngang. : Dng in stator theo trc dc v
ngang. : T thng mc vng cun stator theo trc dc v ngang. : in tr thun
cun stator. : Hng s thi gian ca cun kch t. : in p, t thng mc vng,
dng in cun kch t. : Dng in cun n nh theo trc dc, ngang. : T thng mc
vng cun n nh theo trc dc, ngang. : Tr khng ng b ca cun stator theo
trc dc, ngang. : H s tng h gia cun stator v cun kch t theo trc dc.
: H s tng h gia cun stator v cun n nh theo trc dc. : H s tng h gia
cun stator v cun kch t theo trc ngang. : Vn tc gc ca t trng quay. :
i lng so snh c bn ca vn tc quay t trng
id , iqd , qr Tf
uf , f , ifiD , iQD ,Q
Xd , Xq
d, d
q
b
19
g1 g2
: H s tng h gia n nh v cun kch t theo trc dc. : H s tng h gia n
nh v cun kch t theo trc ngang
3.2.1.2 Mt s gi tr so snh c bn. a) i vi in p cun stator:
ub = u pn. 2u pn . 2:Bin ca in p pha nh mc. : L in p pha nh mc
ca my pht.
(3.2)
u pnIb = In 2
b)i vi dng in cun stator. (3.3)
In 2
:Bin ca Im. :Dng in nh mc.
IbRb =
c) in tr cun stator.
Ub Ib d) i vi in p v dng in kch t.
(3.4)
ufb = uf 0cun stator.
: in p cun kch t khi khng ti ng vi gi tr nh mc ca in p
I fb = I f 0in cun stator.
: Dng in cun kch t khi khng ti ng vi gi tr nh mc ca dng
rf =
Um Im
: in tr thun cun kch t.
e) i vi vn tc quay.
b = n
(3.5)
nfn
: L vn tc quay nh mc ca t trng quay ( n = 2 . f n ) : L tn s m
ca my pht.
2) n gin ho h phng trnh ca my pht ng b khng chi than. n gin ho h
phng trnh ca my pht ng b khng chi than ngi ta tm cch b i nhng phng
trnh hoc nhng i lng khng nh hng nhiu n qu trnh thay i cng nh tnh n
nh ca my pht ng b vi chnh xc nht nh, c th l c th loi b i cun n nh
(b qua phng trnh (4), (5) v phng trnh (9), (10) cn nhng phng trnh
khc b qua nhng i lng lin quan n cun n nh). B qua in tr thun ca cun
stator: r = 0. B qua cc thnh phn khng tun hon ca cun stator
20
(coi
dd dq = = 0) dt dt
Coi vn tc ca Diesel l khng i v lun bng nm ( (1) (2) (3) (6)
(7)
= 0 ).(1) (2)
H phng trnh (3.1) ca my pht ng b c vit nh sau:
ud = q u q = d u f = if + Tf . df dt
(3) (4) (5) (6)
(3.6)
d = if X d .id q = X q .iq
f = if d . X d .id (8) Thay phng trnh (5) vo (1) ta c:
u d = X d .idTng t ta thay phng trnh (4) vo (2) ta c:
(1')
uq = if X d .id u d = X d .id uq = if X d .iduf = if + Tf .(1')
(2')
(2')
Nh vy h phng trnh ca my pht ng b khng chi than c dng sau:
f = if d . X d .id
df dt
(3.7) (3') (4')
4. S tng ng, th vect my pht ng b cc n khng bo ha. Trong ch ti i
xng, my pht ng b ba pha c dng chy trong cun dy phn ng v dng chy
trong cun kch t.
21
f
kt
fa
c)
fs
Hnh (40). S cc t thng c to ra trong my pht ng b
Ekt
E
a
E
E
s
Xa Ea
X
s
R UR
IU
O
R
E
E
ES
kt
U
tij
Hnh (40). S tng ng, th vect my pht ng b cc n khng bo ho (Hnh v
1.14 )Ekt- S cm ng trong cun phn ng do t thng kch t fkt Xa- Tr khng
phn ng phn ng do t thng fa gy ra Xs- Tr khng do t thng tn fs gy ra
R- in tr thun cun dy phn ng T thng do dng chy trong cun kch t gy ra
l kt lm cm ng trong cun dy phn ng mt sut in ng Ekt. Dng ti chy
trong cun dy phn ng gy ra t thng a m phn ln ng sc ca chng i t Stato
qua khe kh mc vng vi cun dy kch t. T thng ny gi l phn ng phn ng a.
Mt phn t thng do dng ti gy ra ch mc vng vi chnh cun dy phn ng ta gi
l t thng tn s (cc hnh: a, b, c). T l lun trn ta c th thnh lp s tng
ng hnh . T s tng ng ta c th vect hnh ... Ekt - s cm ng trong cun dy
phn ng do t thng kch t kt
22
Xa - Tr khng phn ng phn ng do a gy ra v cm ng trong cun dy phn
ng s Ea. Xs - Tr khng do t thng cm s m cm ng trong cun phn ng s Es.
R - in tr thun ca cun phn ng. Ta c : Xa = La Xs = Ls Tng ca hai tr
khng trn: X = Xa + Xs ta gi l tr khng ng b Trong my pht ng b khng
bo ha, s Ekt t l thun vi dng kch t Ikt. T s tng ng ta c biu
thc:
U = E kt E a E s U rX I E
j j XIU
j E a Es+ XI +E U
ktti
kt
j
Hnh (1.15 ). S tng ng, th vect rt gn ng b cc n khng bo ho M ta
c:
E a = jX a I
E s = jX s I
U r = RI
Nn U = E kt jX a I jX s I R I Trong thc t, my pht ng b tr s R rt
nh so vi X nn ta c th n gin ha s tng ng v th vect nh trn. 5 . Cc c
tnh c bn ca my pht ng b . a) c tnh khng ti . L mi lin h E = f( Ikt
) Khi n = const . b) c tnh ngoi ca my pht ng b c tnh ngoi U = f(I)
xc nh s thay i in p ca cun dy phn ng ph thuc vo cng dng ti. Khi gi
tc quay n = const, h s cng sut cos = const v dng kch t Ikt= const.
Cc my pht ng b c s thay i in p rt ln trong qu trnh nhn ti v ct ti.
Ngi ta a ra khi nim s thay i in p nh mc (cho my pht khi ng n tc nh
mc v gi tc khng i, iu chnh cho in p bng Um gi cho cos trong qu trnh
nhn ti khng i cos = const dn ti cho n nh mc).
23
U cos p= 0 j
U = vi n = const f(I) I = const jkt cos = const My pht K6
ng c
j cos = 1
K5 K3 i=0 cos j K4 Ew =Uo j cos i K1 K2 I ngm E kt 0 I ngm
cos p= 0 j
I
Hnh (42). H c tnh ngoi ca my ng b vi cng tr s Ikt v cc tr s cos
khc nhau.
( Hnh v 1.16) S thay i in p nh mc ca my pht ng b trong khong t
40 50%. Chnh v vy bt c my pht ng b no cng phi c trang b b t ng iu
chnh in p. c) c tnh iu chnh ca my pht ng b . c tnh iu chnh ca my
pht ng b: Ikt = f(I) xc nh s thay i cng dng kch t Ikt ph thuc vo s
thay i cng dng ti trong qu trnh gi cho cos = const; n = const v U =
const. T c tnh iu chnh hnh ta rt ra mt s nhn xt nh sau: - Khi dng
ti cng tng th dng kch t cng tng vi cc iu kin (U=const, cos = const
v n = const) - Vi cc ln ca cos khc nhau v cng mt ln ca in p my pht
th dng kch t cng tng cng vi s gim dn ca cos .
1.4 MY B NG BKhi nim b ng b l ci thin cos ca li in qua ci thin
cos ca my pht. thc hin vn ny ngi ta thng s dng in hoc l my b ng b.
T hnh a, trm pht va cung cp cng sut tc dng P v cng sut phn tc dng
Qo thng qua ng dy di.
24
a)Trm pht in
F
P Qc
ng di P Qc
P Qc
Hnh (45). S cp nng lng in i xa a) ng di v ng dng my b ng b ti ch
b)
b)Trm pht in
F
P
P
P Qc
Hnh (45). S cp nng lng in i xa a) ( Hnh v 1.17 ) v ng dng my b
ng b ti ch b) T hnh b, trm pht cung cp cho ph ti ch cng sut tc dng
P thng qua ng dy di nh trn. My b ng b ngay gn ph ti s cung cp cng
sut phn tc dng cm khng cho ph ti. Lm c nh vy trm pht v ng dy s khng
phi chu thnh phn dng cm khng. Cos ca my pht cao, nng cao tnh kinh t
trong khai thc. Nh vy, my b ng b chnh l ng c chy ch khng ti vi dng
kch t nht nh. N ch nhn mt lng cng sut tc dng nh, khng ng k t mng cn
bng cc tn hao v cp cho mng mt lng cng sut phn tc dng cm khng. Mun
thc hin c iu trn ta phi cng kch cho my c s vect di y. Ngoi nhim v
lm tng cos ca mng ng c ng b cn l b iu chnh in p cho mng . V khi ta
thay i Ikt lm thay i tr s dng in ca n suy ra gin tip lm thay i ging
p trn ng dy k t trm pht. My b ng b ngy nay cng c ng dng rt rng ri
trn tu thu c my pht ng trc v b bin i nghch lu. N ch thc hin chc nng
cp cho mng cng sut cm khng thay cho my pht ng b,m my pht ng trc m
khng th cp c.
1.5 MY PHT NG TRC Mc in kh ha v t ng ha trn tu thu ngy cng pht
trin i i vi s gia tng cng sut ca trm pht in. l nguyn nhn c bn a n
vic ng dng my pht ng trc lm ngun nng lng in chnh trn tu. Mt khc
trong qu trnh khai thc a n kt lun l: Khi ng dng my pht ng trc gi
thnh 1KW/h thp hn 50% gi thnh khi ng dng my pht c diesel hoc tuc
bin quay ring. Mt nguyn nhn quan trng na, c rt ra t thc t khai thc
l: tuy s lng my pht in trn tu c t 3 5 cm song khi tnh tng cng s gi
lm vic ca mi ci vn ln hn nhiu so vi s gi lm vic ca my chnh quay chn
vt. V thi gian tu ng trong cng bc xp hng ha v neo i chim t l cao so
vi thi gian i trn bin. Do vy tui th ca cc my chnh bao gi cng di hn
tui th ca cc my ph truyn ng cho cc my pht in.
25
Tuy nhin khi ng dng my pht ng trc i hi h thng cng tc n nh trong
gii hn thay i tc quay chn vt t 60 100% tc nh mc. Gii hn trn c lin
quan n s n nh in p v tn s ca dng in vi chnh xc cho php theo yu cu
ca ng kim. truyn ng cho my pht ng trc trong thc t p ng cc phng php
sau: - Truyn ng qua hp s bnh rng. - Truyn ng qua dy curoa hay bng
xch. - Truyn ng trc tip tc l Roto ca my pht ng trc l mt on ca trc
chn vt . iu kin cng tc ca my pht ng trc khc nhiu so vi iu kin cng
tc ca cc my pht c truyn ng ring. l s thay i tc quay trong cc ch cng
tc ca tu nh : - Ch iu ng. - Ch tu hnh trnh qua knh. - Ch tu hnh
trnh trong sng gi ln. S thay i tc quay dn n: - Nu my pht ng trc l
my pht mt chiu th lm thay i in p ca my pht. - Nu l my pht xoay chiu
th khng nhng lm thay i in p m cn lm thay i tn s ca dng in my pht.
Chnh v vy vn gi n nh cc thng s c bn: in p, tn s cho my pht ng trc l
rt phc tp.
My pht ng trc l mt phn trc chn vt
SG PW
My pht ng trc c t i din vi chn vt qua my diesel
SG PW SG PW
My pht ng trc c lp t ngay trn my diesel chnh
My pht ng trc c truyn ng qua hp s cng pha chn vt
PW
P
SG
My pht ng trc c truyn ng qua hp s pha i din vi chn vt
SG P PW 26
My pht ng trc c truyn ng qua hp s ngay cnh my chnh.
SG
PW
Hnh (1.18 ). Cc phng php lp t truyn ng cho my pht ng trc trn tu
thu. *Cc phng php n nh tn s cho my pht ng trc c p dng nh sau: Vn n
nh tn s cho cc my pht ng trc l rt quan trng . Trong thc t chng ta c
th s dng cc phng php sau: 1.Phng php th 1 . My pht ng trc l my 1
chiu: cung cp nng lng quay ng c 1 chiu c tc khng i. ng c ny li quay
my pht ng b. Phng php ny c nhiu nhc im. - Cng mt lc s dng nhiu my
in. - Gi thnh cao, chim ch nhiu, hiu sut thp. 2. Phng php th 2 . My
pht ng trc c ch to l my pht ng b bnh thng. Ton b nng lng in xoay
chiu c bin i ra nng lng in 1 chiu qua chnh lu. Sau nh nng lng ny li
c bin i ra nng lng xoay chiu 3 pha c tn s n nh nh b bin i nghch lu
v b iu chnh tn s ring. 3. Phng php th 3 . My pht ng trc c kch t bng
dng xoay chiu. Roto (cun kch t) c th c ch to 3 pha, 2 pha hoc 1
pha. Dng kch t l dng xoay chiu c tn s c iu chnh nn sinh ra mt t
trng quay so vi bn thn roto. Tc quay ca t trng ny c chn sao cho tng
ca tc quay roto v tc quay ca t trng dng kch t p ng c tn s cn thit
cho mng in tu. Cch gii quyt nh trn c nhiu u im. B bin i tn s khng
phi tnh ton chu ton b cng sut ca my pht ng trc m n ch chu cng sut
kch t. B bin i tn s ny ch cn ca ra c tn s 40% tn s ca mng. Nh vy rt
ph hp vi s thay i tc quay ca trc chn vt trn tu. Ch to nhng b bin tn
nh trn n gin v gi thnh khng cao lm. B iu chnh in p v tn s c ch to
bng bn dn rt phc tp. My pht ng trc loi ny c th cng tc c ch khi trn
mng c in p. Chnh v vy my pht ng trc thng c cng tc song song vi cc
my pht khc t kch lc ban u. Sau khi n nhn ti th c th lm vic ring bit
c.
Cu hi n tp chng1. 1) C to , nguyn l hot ng , phn loi v cc c tnh
c bn ca my pht in 1 chiu. 2) Cu to, nguyn l hot ng , phn loi v cc c
tnh c bn ca my pht in ng bxoay chiu ?
3) So snh u nhc im ca loi my pht xoay chiu c chi than v loi my
pht in xoaychiu khng chi than.
4) S tng ng , cc phng trnh c bn ca my pht in ng b xoay chiu . 5)
Cc phng php n nh tn s cho cc my pht ng trc trn tu thu. 27
