n p Buck - ConverterNhm 3

BO COBI TP LN IN T CNG SUT TI :THIT K MCH GIM P BUCK CONVERTERGVHD : TS Hn Huy Dng Sinh vin thc hin:Trn Hi Bnh - 20125403V Cng Hon - 20125542L Th Long - 20125644Nguyn Tin Quang - 20125728Nguyn Vit Thanh - 20125770

H Ni 6/2015

MC LCLI NI U3I.GII THIU TI41.Tng quan v n p Buck42.Ch hot ng42.1Ch dn lin tc42.2Ch dn khng lin tc5II.PHN TCH MCH51.S tng quan cc khi52.Mch Buck l tng63.Nguyn l hot ng ca mch6III.TNH TON GI TR V MCH BUCK71.Chu k chuyn mch72.Chu k nhim v ( rng xung )73.Tnh ton gi tr in p ra ( Uout )83.1Khi van m :83.2Khi van kha ta c :84.Tnh ton gi tr cun cm9IV.THIT K B TO XUNG VI TN S 10KHZ DNG IC 555101.S nguyn l mch to xung102.Tnh ton gi tr ca tn s10V.TNH TON CC GI TR TIN HNH M PHNG V LM MCH111.Tnh ton cc gi tr trong mch Buck111.1Chu k chuyn mch T:111.2Thi gian van ng t1:111.3 rng xung D111.4Gi tr cun cm L:112.M phng122.1S m phng trn Psim122.2Kt qu m phng132.3 th dng xung iu khin to ra bng IC555163.Tin hnh lm mch163.1S nguyn l :163.2S mch in173.3Mch thc t18VI.NHN XT181.u im:182.Nhc im:18KT LUN19

LI NI U Chng ta ang sng trong th k 21,th k ca cch mng khoa hc v cng ngh. in, in t pht trin ngy cng mnh m v mang li nhng ng dng v cng to ln cho s pht trin kinh t trn ton th gii. in t cng sut l cng ngh bit i in nng t dng ny sang dng khc trong cc phn t bn dn cng sut ng vai tr trung tm. in t cng sut c ng dng rng ri trong hu ht cc ngnh cng nghip hin i. Trong cc my mc thit b cng nghip,cng nh i sng hng ngy u phi s dng in nng, c nhng thit b hot ng trong di in p ln, cng c thit b hot ng trong di in p nh. cho cc thit b hot ng trong di in p thp chng ta cn rt nhiu b chuyn i khc nhau p ng di in p cho cc thit b . Trong bi tp ln ln ny, chng em la chn mt b chuyn i c chc nng l Mch gim p Buck Converter.

Bng phn cng cng vicSTTH v tnNi dung cng vic

1L Th LongLm m phng v v mch in

2Trn Hi BnhTm hiu nguyn l v mua linh kin

3V Cng HonVit bo co

4Nguyn Tin QuangThit lp cng thc

5Nguyn Vit ThanhLm mch in

I. GII THIU TI Tng quan v n p Buck Buck Converter l b bin i m in p u ra nh hn in p u vo hay cn c gi l b bin i gim p.Mch Buck l mch c chc nng gim in p u vo ca b chuyn i xung in p thp hn v n nh hn ng dng : + Trong cc ng c m t 1 chiu .+ Cho cc thit b hot ng trong di tn thp+ Mch n gin + Cung cp in mt chiu v iu khin tc ng c mt chiu Ch hot ng Dng IL khng i Dng IL khng lin tc vi VD l hng s Dng IL khng lin tc vi VO l hng s 1.1 Ch dn lin tc

L ch : dng dn lin tc v IL bng 0 ti hai u mt 1.2 Ch dn khng lin tc

L ch : trong mt chu k IL = 0 trong khong 2.TSII. PHN TCH MCH1. S tng quan cc khi

2. Mch Buck l tng

Cu to mch: Diode : bo v kha T trong gia khong thi gian Ton v Toff trnh c dng d chy ngc li nh thng kha T Kha T : iu chnh in p u ra bng cch thay i chu k ng ngt B lc thng thp : gm cun cm v mt t in c chc nng n nh in p u ra Vd : in p u vo ca mch Nguyn l hot ng ca mchGi T l chu k chuyn mch, t1(ton) l thi gian ng mch (on-time) v t2(toff) l thi gian m mch (off-time) Trong khi on-time th in p u vo c a vo mch Vin=V1, Diode s b phn c ngc v b kha li, khi dng in s qua cun cm v cun cm L1 s np nng lng. Chiu dng in nh hnh v:

Trong khi van off-time th cun cm L phng in chng li s gim t ngt dng in trong mch v tip tc dn dng in i qua ti, i qua R v Diode,kt qu in p V1=0. Trong thi gian van off-time th in p V1=0 nhng dng in L I vn khng gim v 0. y c gi l ch Continuous mode. Chiu dng in nh hnh v:

III. TNH TON GI TR V MCH BUCK1. Chu k chuyn mch

Trong : t1 l thi gian van ng mch (on time ) t2 l thi gian van m mch (off time)2. Chu k nhim v ( rng xung )

3. Tnh ton gi tr in p ra ( Uout )

3.1 Khi van m :

Thi gian : 0t