kshitij nagle final report

8/13/2019 Kshitij Nagle Final Report

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Major Project reporton

Buck Boost Converter

Submitted in partial fulfillment of the requirement for the award of Degree ofBachelor of Engineering in Electricals And Electronics Engineering BE VIISem.

Submitted to

RAJIV GAND I !R"#D$"GI%I VI& 'AVID$A(A$A)B "!A( *+,!,-

Submitted By

%shiti. Nagle */0/0E12/2/23-Jitendra Akode*/0/0E12/2/24-!a5an Gu6ta*/0/0E12/2/78-

+a9ur Raghu5anshi*/0/0E12/2/:;-

Department of Electrical! Electronic! EngineeringIn!titute of Engineering and Science" IPS #cademy" Indore $MP%

Se!!ion &'()*(+


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DE!AR


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DEC(ARA9

Indore*+,!,- " hereby declare that the wor2 pre!ented in thi! report entitled

Buck Boost Converter i! the outcome of my own wor2" i! bonafide and

correct to the be!t of my 2nowledge and thi! wor2 ha! been carried out

ta2ing care of Engineering Ethic!.

%shiti. nagle*/0/0E12/2/23- Jitendra Akode*/0/0E12/2/24-

!a5an Gu6ta*/0/0E12/2/78- +a9ur Raghu5anshi*/0/0E12/2/:;


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AC%N"'(EDGE+EN<

E0ery !tudent ta2e! an indomitable urge" per!e0erance" and proper guidance

e!pecially when it i! mo!t needed.

I wi!h to e?pre!! my !incere gratitude toward! Mr. Manoj

1upta3,raining Ao*ordinator4 for pro0iding me their in0aluable time and !upportduring the training. I would al!o li2e to than2 all the !taff member! of S#,P /#

,=E/M#C P>@E/ S,#,I>6" S#/6I for their guidance and !ugge!tion! at all

!tage! of training. ,heir con!tructi0e critici!m of the approach to the problem and

the re!ult obtained during the cour!e of thi! wor2 ha! helped u! to a great e?tend

in bringing thi! wor2 to it! pre!ent !tate. I would li2e to than2 =ead of

Department Prof. B.6 P=#D5E" Dr. #rchana 5reeti Ahowdhary Principal IES"

and all teaching and non teaching !taff for their con!tant !upport. ,heir in!pired!tint! and their e?perience and 2nowledge pro0ided me with educati0e !upport.

=ere I than2 from the core" e0erybody who ha! helped me to at wor2. In true

!en!e" be!ide! my guide I am indebted to many other member! at IES IPS #A#DEM

for their con!tant help and in0aluable contribution on all occa!ion! when they were mo!t

needed. #gain" I find the opportunity to ac2nowledge regard! and than2 to my family

member! and friend! who ha0e been true !upport behind me.


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5!hitij 6agle 3'7'7E8('('(94 :itendra #2ode3'7'7E8('('(;4 Pawan 1upta3'7'7E8('(')


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,he con0erter will be te!ted o0er the entire range of the input and output

0oltage!. #t each 0alue of input and output the data will be documented. ,he power*out"

power*in" duty ratio" and thermal reading! will al!o be recorded. ,he!e 0alue! will allow

for the nece!!ary calculation! for efficiencie! and thermal rating!.


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De!ign Procedure

# DA*DA con0erter i! nothing more than a DA tran!former or a de0ice that

pro0ide! a lo!! le!! tran!fer of energy between different circuit! at different 0oltage

le0el!. @hen dc*dc con0er!ion i! needed there i! al!o a need for control and a need for

higher efficiencie!. If the latter were not important we could ju!t u!e a 0oltage di0ider

and get the change in 0oltage we are loo2ing for. In modern dc electronic! we need more

than ju!t 0oltage reduction. @hat really are needed are 0oltage tran!fer!" polarity

re0er!al!" and increa!ed and decrea!ed 0oltage! with control. >ne method of building adc tran!former i! to u!e !witching con0erter! called chopper!. ,he pro0ided !witching

function require! a duty ratio" which will gi0e u! the control that ha! been needed .

In the Buc2*boo!t con0erter achie0ing output! of any magnitude! are po!!ible.

,he buc2 boo!t con0erter ha! two main re!triction!. ,hey are 5VC and 5AC ha! to be

!ati!fied. ,hi! mean! that only one !witch i! on at a time. @hen !witch ( 3 E,4 i! on the

0oltage V t 3 igure (4 i! ju!t V in and when !witch & 3diode4 i! on V t i! ju!t *V out. ,hen the

duty ratio can be related to V out by !aying V out O(

(

(

P

D

V Din

. ,he input and output current!

are determined by the !witching action. Since I ! OQioutRHQiinR then ( D QioutRO & D QiinR

and becau!e of the ca!cading proce!! thi! con0erter require! a negati0e output with

re!pect to the input. In theory if ( D i! ' then the output i! Nero and if ( D i! ( then the

output i! infinity and if ( D i! &(

then the output i! equal in magnitude to the input. ,he


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capacitor at the output i! there to gi0e the output 0oltage !ource propertie!. ,he method

of determining the other element! of the circuit i! di!cu!!ed in !ome depth in the re!ult!.

Probably the mo!t important con!ideration of all the element! i! the inductor. ,he

inductor 0alue i! important to not be below the critical 0alue !o that the con0erter will not

ha0e a di!continuou! mode. ,hi! happen! when the inductor i! too !mall to maintain

current flow at all time!. @hen the con0erter i! in di!continuou! mode it! output become!

load dependent.

=igure 2


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De!ign Detail!

Since the objecti0e of building a con0erter that will !upply a con!tant F(G 0olt!

the deci!ion to u!e a buc2 boo!t de!ign wa! cho!en due to the polarity re0er!al 3!ee figure

(4. ,he fir!t thing to do wa! to find the 0alue of the !witching frequency for which

CRCcrit. ,o do thi! the 0alue! of the load current" the time period and the duty ratio mu!t

be 2nown !ince the 0alue of C crit i! dependant upon them. ,o obtain the load current we

u!e the following equation! to obtain the data in table +.

I! O QiinR H QioutR 3(4

POVI 3&4

,able*(

,he relation!hip between !witch ( and !witch & i! called the Duty /atio and can

be repre!ented by the following equation"

Vout O 3D( (*D( 4 Vin 3)4

6ow to con!ider the duty ratio and !ince a polarity !hift need! to occur" then the!e term!

will need to con!idered in term! of ab!olute 0alue!. or the (' 0olt ca!eD ( O G&J and D &

O )7J. or the (< 0olt ca!e D ( O


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tOD( , 3+4

V in O Ccrit i t 3 t 0 icRD( , ma? Iout 0 374

,hen in the (' 0olt ca!e yield! AR(.< f and for the (< 0olt ca!e we get AR(7.9 f in thi!

con0erter a +; f capacitor will be u!ed. 6ow that all of the component! ha0e been

!elected for the con0erter it i! time to choo!e the component! of the gate dri0e. #nd


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Design Verification

,he ne?t !tep i! to build the con0erter and to begin te!ting a! !pecified by the

propo!al. ,he te!ting began with the &*watt load and wa! ran at (*0olt inter0al! o0er the

range of input! and continued on with the &'*watt load. @hile doing thi! data wa!

collected to compare the duty ratio" efficiency and the output. Data ta2en in the &*watt

range i! gi0en below

Test DataFrequency 85khzLowoutput

WithWave Fet

Vin Vout Pin Pout Efficiency Duty Ratio!"!8 5"#8 $"% $ %&"!% $!

"!' (" '"( $"% %5"!! 8$"!' 5"#& '" $"& %%"&$ ('"! (" '" $"' %&" # && (" '"$ $"' % "88 $5"! (" ' $"$ %'"'' #

,able &

,he data in ,able & i! data ta2en with the @a0e E,. #! !hown in the data the F(G0 at &*

watt! output wa! achie0ed and the efficiency achie0ed i! in the mid ;'J range" not a!

high a! we had anticipated but it i! better than the efficiencie! that were ta2en with the

!tandard E, a! !hown in ,able )

With)tan*ar*FET

Vin Vout Pin Pout Efficiency Duty Ratio! ( '"' $" ('"(& $

"! ("! '"5 $"' (5"% #$"!' (" '"( $"5 (#"&& %'"!$ ( '"( $"& (("(% (& 5"#8 '"$ $" (5"(' &5"!' 5"## '"& $"$ (&"% !

,able )


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,he thermal di!!ipation data i! a! follow!

Ther+a,Dissipation

)tan*ar*FET

Wave FET

W - noheat sink

W - noheat sink

. of FET $ /para,,e,0 . of FET $ /para,,e,0$ Watts 5' && $ Watts '# '$! Watts 11 $5 1 $5 $! Watts 1 $5 !

W - 2eatsink

W - 2eatsink

. of FET $ /para,,e,0 . of FET $ /para,,e,0$ Watts &( '& $ Watts ' $#$! Watts ! 8% $! Watts 8( (#

,able G

#! !hown in the data to operate in the high power range the u!e of heat!in2! were

required but the objecti0e wa! met with two @a0e E,! in parallel.

,he !witching trajectorie! loo2ed li2e the following


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igure )

#n ideal !witching trajectory would ha0e a more linear !lope in the turn on and

turn off time there for thi! one i! not to far off. #ltering the !witching trajectory i! the

!ole job of the !nubber circuit. ,he capacitor and re!i!tor in the !nubber !hould be

!ufficient enough to a0oid the 0oltage o0er !hoot and to pro0ide an /A time con!tant

large enough to totally di!!ipate the !tored energy during the turn on time. ,he !nubber

needed to be incorporated to operate the con0erter at the high power end of the output

due to the fact that the E, wa! not turning on !oon enough to allow the con0erter to

operate at the !pecified frequency.


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Aonclu!ion,he efficiencie! were not where they were e?pected to be and thi! i! becau!e the

input! of the con0erter were 0ery !mall compared to the output requirement!. ,he

efficiencie! ri!e a! the input 0oltage ri!e! and the duty ratio decrea!e!. ,hi! i! becau!e a!

the input 0oltage ri!e! and the duty ratio decrea!e! the !witching lo!!e! in the E, are

reduced and the current dri0ing the con0erter i! reduced. ,here could ha0e been !ome

change! in the de!ign of the con0erter in the early !tage! to po!!ibly increa!e the

efficiencie! but thi! would ha0e had to be !et forth in the beginning. Such a!" if we had

cho!e to build the con0erter for a !pecified load we could ha0e cho!en the input to bemore helpful to the gate dri0e and therefore increa!ing the efficiency. #! it !tand! the

efficiency of the con0erter range! from the low 0er all the circuit could ha0e been built in

a relati0ely !mall pac2age of two inche! by three inche! with the E, mounted to the

bac2 of the heat !in2. ,hi! i! clo!e to indu!try !tandard!" an a0erage dc*dc con0erter will

be about )inche! by )inche! and larger a! the power requirement! increa!e.


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Ao!t

PartsLis

t

Line 3uantity Discription 4ost Tota,$5k h+ Resistor 6!" % 6!" %

$ 5!! h+ Pot Resistor 6!"#' 6!"#'' k h+ Resistor 6!"!( 6!"!(& $k Resistor 6!"!# 6!"!#5 $ /$0 (8k Resistor 6!"' 6!"($( !"!!&%+F 4apacitor 6!"'& 6!"'&

% $ /$0 !"! +F 4apacitor 6!"$% 6!"5&8 $ /$0 R7(!D Dio*es 6!"&' 6!"8(# &%k Resistor 6!"$# 6!"$#! +F 4apacitor 6!"$' 6!"$'

9R !&5 Dio*e 6!"5' 6!"5'$ +F 4apacitor 6!"%8 6!"%8' $8 h+ Power Resistor 6!" 8 6!" 8& $"8k h+ Power Resistor 6!" # 6!" #5 !"$$!+F 4apacitor 6!"&& 6!"&&( :RF5$! Fet 6!"5( 6!"5(% ;4'8&' PW :4 6 "(% 6 "(%

Tota,4ost

68"&8

,otal labor i! projected at about )& hour! of lab time and (' hour! of de!ign and

re0iew for a total of +& hour! per per!on and at a !alary of )' an hour. ,otal price of

G")''.'' for labor and part! are 7.+7 for a grand total of G")'7.+7.


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kshitij nagle final report

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