The research paper published by IJSER journal is about Design of Dc-Dc Converter with Maximum Power Point Tracker Using Pulse Generating (555 Timers) Circuit for Photovoltaic Module 1

ISSN 2229-5518

Design of Dc-Dc Converter with Maximum Power

Point Tracker Using Pulse Generating (555

Timers) Circuit for Photovoltaic Module

Ainah Priye Kenneth

Abstractdue to the decline in power of photovoltaic module as a result of changes in irradiation which affect the photovoltaic module performance, the design and implementation of DC-DC boost converter operating in continuous conduction mode with a Maximum power point tracker using a Microcontroller connecting a 555 timer circuit to generate Pulse W idth Modulation (PW M) signal to estab lished a constant output voltage was proposed. The system is a close loop system and continuously measure samples of current and voltage from output of photovoltaic module and reference voltage at the load (lead base light, 24V) to obtain instantaneous power. Base on this, the 555 timer circuit (pulse generator) constantly takes in DC voltage through a current source to control the duty cycle of the DC -DC boost converter. Also PSIM and Pspice software were used to simulate DC -DC boost converter and compare simulation results with the practical operation of the design system.

Index TermsDC-DC boost converter, Maximum power point tracker, Photovoltaic module, Pspice; Pulse width modulation, Microcontroller.

—————————— ——————————

1 INT RODUCT ION :

A c c or d i n g t o [ 1 ] D C - D C c on ve r t e r s a r e w i d e l y u se d i n r e g u l a t e d sw i t c h mo d e D C p ow e r su p pl i e s. Th e i n pu t of t h e se c o n ve r t e r s i s u n r e g u l a t e d D C vol t a g e , w h i c h i s ob t a i n e d b y P V a r r a y a n d t h e r e f or e w i l l b e f l u c t u a t e d d u e t o c h a n g e i n r a d i a t i on a n d t e m pe r a t u r e . R e n e w a b l e e n e r g y i s g r ow i n g r a pi d l y a n d i t i s b e c o mi n g si g n i f i c a n t i n ou r w or l d t o d a y a n d i n t h e f u t u r e t o c o m e . P h ot ov ol t a i c ( P V ) i s on e of t h e m o st i m p or t a n t a r e a i n t h e f i e l d of r e n e w a b l e e n e r g y a n d h a s a t t r a c t e d l ot s of r e se a r c h . I n t h e pa st y e a r s, P V p ow e r g e n e r a t i on sy st e m s h a ve a t t r a c t e d a t t e n t i on d u e t o t h e e n e r g y c r i si s a n d e n vi r on m e n t p ol l u t i on . P h ot o v ol t a i c p ow e r g e n e r a t i o n sy st e m s c a n mi t i g a t e e f f e c ti ve l y e n vi r on me n t a l i s su e s su c h a s t h e g r e e n h ou se e f f e c t a n d pol l u t i on [ 2 ] . O n e ma j or pr ob l e m w i t h ph ot ov ol t a i c m od u l e i s t h a t t h e e l e c t r i c al ou t pu t po w e r d e pe n d s on t h e w e a t h e r c on d i t i on t h a t i s; t h e ou t pu t i s c h a n g i n g w i t h a c h a n g e i n w e a t h e r c on d i t i on w h i c h ma k e s ph ot ov ol t a i c mo d u l e n on l i n e a r p ow e r s ou r c e . D u e t o t h e w e a t h e r c on d i t i on me n t i on a b ove a n d ot h e r f a c t or s l i st e d b e l ow i n ( 2 . 0 ) , t h e ma x i mu m p ow e r p oi n t of t h e ph ot ov ol t a i c m od u l e a s d e sc r i b e b e l ow i n f i g u r e ( 5 , 6 ) w i l l sh i f t a w a y f r o m t h e ma x i mu m o pe r a t i n g poi n t of t h e m od u l e . B a se on t h i s r e su l t a ma x i mu m po w e r poi n t t r a c k e r ( M P P T) e m pl o y i n g D C - D C c o n ve r t e r i s d e ve l o p a n d u s e d
t o ma i n t a i n t h e ma x i mu m po w e r poi n t ( M P P ) of t h e m od u l e . M a n y M P P T me t h od s h a v e b e e n d e ve l o p ov e r t h e y e a r s t o a c h i e ve t h e ma x i mu m p ow e r p oi n t of t h e P V mo d u l e i n d i f f e r e n t pa pe r s; e x a m pl e s a r e t h e i n c r e m e n t a l c on d u c t a n c e ( I C ) me t h od [ 3 ] , pe r t u r b a t i on a n d ob se r ve ( P & O ) me t h od [ 2 ] , t h e f u z z y l og i c [ 2 ] , mi c r oc on t r ol l e r b a se me t h od [ 4 ] [ 5 ] e t c . I n t h i s pa pe r i t i s i n t e n d e d t o d e si g n a n e a sy t o u se D C - D C c on ve r t e r ( b o o st c on ve r t e r ) w i t h ma x i mu m p ow e r p oi n t t r a c k e r f or ph ot ov ol t a i c mo d u l e t o c on t r ol t h e ph ot ov ol t a i c i n t e r f a c e so t h a t t h e o pe r a t i n g p oi n t of t h e l oa d a n d ph ot o v ol t a i c m od u l e me e t a t t h e ma x i mu m p ow e r p oi n t n o ma t t e r t h e e l e c t r i c a l pow e r ou t p u t of t h e m od u l e . Th e c on ve r t e r w i l l b e c on n e c t e d b e t w e e n t h e p h ot ov ol t a i c m o d u l e a n d t h e l oa d ( a l e d b a se d l i g h t w i t h n o mi n a l v ol t a g e of 2 4 V ) w i t h ou t a b a t t e r y so a s t o su p pl y t h e l oa d w i t h
2 4 V a t a l l t i me . Th e d e si g n w i l l b e u se d b y b o t h sk i l l e d a n d u n sk i l l e d pe o pl e , a n d w i l l b e b o t h p or t a b l e a n d pr a c t i c a l i n t h e f i el d o f e n g i n e e r i n g a n d r e n e w a b l e e n e r g y . Th e me t h od i n t h i s pa pe r i s a f e e d b a c k mi c r oc on t r ol l e r b a se d M P P T c on t r ol me t h od w i t h a b o o st c on ve r t e r o pe r a t i n g i n c on t i n u ou s c on d u c t i on m od e . Th i s c h a r a c t e r i st i c of c on t i n u ou s i n pu t c u r r e n t ma k e s t h e b o o st c on ve r t e r s u i t a b l e a s ph ot ov ol t a i c i n t e r f ac e . Th e b l oc k d i a g r a m of t h e a d o pt e d me t h od i s d e sc r i b e d b e l ow i n f i g u r e 3 . Th e c om p on e n t u se d i n t h e pr o p o se c o n t r ol d e si g n i s a pu l se g e n e r a t or

IJSER © 2012

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The research paper published by IJSER journal is about Design of Dc-Dc Converter with Maximum Power Point Tracker Using Pulse Generating (555 Timers) Circuit for Photovoltaic Module 2

ISSN 2229-5518

( 5 5 5 t i me r c i r c u i t ) t o c h a n g e t h e d u t y c y c l e , a mi c r oc on t r ol l e r a n d a g a t e . I n t h e pr oj e c t w e w i l l
a l so d e si g n a n d i mpl e me n t t h e D C - D C c o n ve r t e r
( b o o st c on ve r t e r ) .

2 OVERVIEW OF PHOT OVO LT AI C ARR AY :

P h ot ov ol t a i c c e l l a l so k n o w n a s sol a r c e l l i s u s e d t o c o n ve r t e n e r g y f r o m t h e su n d i r e c t l y i n t o e l e c t r i c al e n e r g y w i t h ou t a n y f or m of r ot a t i on a l pa r t s. P h ot ov ol t a i c c e l l s r e pr e se n t t h e b a s i c f u n d a me n t a l p ow e r c on ve r si on u n i t of ph ot ov ol t a i c sy st e m. T h e se c e l l s a r e ma d e f r o m se mi c on d u c t or s a n d l i k e a n y ot h e r s ol i d - st a t e e l e c t r on i c d e vi c e s e . g d i od e , t r a n si st or s a n d i n t e g r a t e d c i r c u i t , t h e y h a ve si mi l a r b e h a vi o r . P h ot ov ol t a i c c e l l s a r e u su a l l y a r r a n g e d i nt o m od u l e s a n d a r r a y w h e n a p pl i e d pr a c t i c a l l y [ 6 ] . Th e r e a r e d i f f e r e n t t y pe s of ph ot o vol t a i c c e ll s a va i l a b l e on t h e ma r k e t a n d y e t d i f f e r e n t ot h e r t y pe s of c e l l s a r e u n d e r d e ve l o p me n t e . g . d y e - se n si t i z e d N a n d - c r y st a l l i n e c e l l s. Th e r e a s on f or d i f f er e n t t y pe s of ph ot o v ol t a i c c e l l , ma t e r i a l s a n d st r u c t u r e i s t o e x t r a c t ma x i mu m po w e r f r om t h e c e l l a n d t o ma i n t a i n c o st t o a mi n i mu m. A c c or d i n g t o [ 6 ] e f f i c i e nc y a b ove 3 0 % h a ve b e e n a c h i e ve d i n l a b or a t or y a n d e f f i c i e n c y of pr a c t i c a l a ppl i c a t ion i s u su a l l y l e s s t h a n h a l f of t h i s va l u e . C r y st a l l i n e si l i c on t e c h n ol og y i s w e l l e st a b l i sh e d a n d i t s c e l l i s m or e e x pe n si ve b u t st i l l c on t r ol s a ma j or pa r t of t h e p h ot o vol t a i c ma r k e t w i t h e f f i c i e nc y a p pr oa c h i n g 1 8 % . O t h e r t y pe s of ph ot o v ol t a i c c e ll s l i k e a mor ph ou s t h i n f i l ms a r e l e s s e x pe n si ve b u t w i t h d i sa d va n t a g e of po or e f f i c i e n c y . Th e r e a r e se v e r a l f ac t or s t h a t a f f e c t t h e el e c t r ica l pe r f or ma n c e of a ph ot o v ol t a i c mod u l e f r o m o pe r a t i n g a t o pt i ma l o pe r a t i n g poi n t . Th e se f a c t or s a r e ( 1 ) S u n l i g h t i n t e n si t y / i r r a d i a t i on ( 2 ) C e l l t e m pe r a t u r e ( 3 ) L oa d r e si st a n c e a n d ( 4 ) S h a d i n g a n d t h e u se of ph ot o v ol t a i c a r r a y a n d ma x i mu m p ow e r p oi n t t r a c k e r ( M P P T) t o c u r b t h e se c h a l l e n g e s a r e d e ve l opi n g r a pi d l y .

3 OVERVIEW O F DC -DC CONVERT ER:

DC - D C c on ve r si on t e c h n ol og y i s a ma j or su b j e c t a r e a i n t h e f i e l d of pow e r e l e c t r on i c , p ow e r e n g i n e e r i n g a n d d r i ve s. Th e c o n ve r si on me t h o d s h a ve a p pl i c a t i on i n i n d u st r i e s su c h a s t e l e c om mu n i c a t i on s, a u t o m ot i ve , r e n e w a b l e e n e r g y , r e se a r c h e t c a n d h a ve g on e u n d e r se r i e s of
d e ve l o p me n t a l st a g e s f or m or e t h a n si x t y ( 6 0 y e a r s) . Th i s c on ve r si on t e c h n i q u e i s w i d e l y
a d o pt e d i n i n d u st r i a l a p pl i c a t i on a n d c om pu t e r h a r d w a r e c i r c u i t s. Th e i d e a s of D C - D C c on ve r si on t e c h n i q u e a n d d e ve l o p me n t h a ve b e e n on f or ov e r
8 0 y e a r s. Th e si m pl e st D C - D C c on ve r si on
t e c h n ol og y i s a vol t a g e d i vi d e r , p ot e n t i o me t e r a n d
s o on . B u t t h e e f f e c t of t h e se si mpl e c on ve r si on t e c h n i q u e s r e su l t e d i n p o or e f f i ci e n c y d u e t o f a c t t h a t t r a n sf e r ou t pu t v ol t a g e i s l ow e r t h a n t h e i n pu t vol t a g e . A c c or d i n g t o [ 7 ] , t h e r e h a ve b e e n m or e t h a n 5 0 0 pr ot ot y p e s of D C – D C c o n ve r t e r d e ve l o pe d f or m or e t h a n 6 0 y e a r s. A l l n e w t o pol og y a n d pr e se n t l y e x i st i n g D C - D C c on ve r t e r s w e r e d e si g n t o me e t s o me sor t of i n d u st r i a l or c om m e r c i a l a p pl i c a t i on s. Th e y a r e u su a l l y c a l l e d b y t h e i r f u nc t i on , f or e x a mpl e , B u c k c on ve r t e r , b oo st c on ve r t e r , b u c k - b oo st c on ve r t e r a n d z e r o - sw i t c h i n g ( Z C S ) a n d z e r o vol t a g e sw i t c h i n g ( Z V S ) c on ve r t e r s w h i c h a r e u se d t o r e d u c e , i n c r e a se vol t a g e < . r e s pe c t i ve l y . D C - D C c on ve r t e r s ( e . g . b oo st , b u c k , b u c k b o o st , e t c ) a r e a l s o i m pl e me n t e d w i t h ot h e r d e vi c e s a s ma x i mu m p ow e r p oi n t t r a c k e r s ( M P P T) f or ph ot o v ol t a i c m od u l e , f or e x a m pl e i n [ 8 ] a r e a l t i me M P P T e m pl oy i n g a D C - D C b oo st c on ve r t e r o pe r a t i n g i n c on d u c t i on mo d e i s u se d . I t a l so i n c l u d e s a pa ss i ve n o n d i s si pa t i ve t u r n on t u r n of f sn u b b e r i n or d e r t o a c h i e ve h i g h e f f i c i e n c y a n d t o r e d u c e E M I l e ve l d u e t o so f t sw i t c h i n g .

3.1 B OOST CONVERT ER AN ALY SIS:

Th e d e si g n e d D C - D C b o o st c o n ve r t e r i s c on n e c t e d b e t w e e n t h e ph ot o v ol t a i c mod u l e a n d t h e l oa d s o a s t o e n a b l e t h e m od u l e o pe r a t e s a t ma x i mu m p ow e r a t a l l t i me . B o o st c on ve r t e r i s ma d e of u p f ou r e l e me n t s a s sh ow n b e l ow i n f i g u r e 1 , t h e y i n c l u d e t h e i n d u c t a n c e , d i od e , c a pa c i t or a n d M 0 S F E T. A s t h e n a me of t h e c on ve r t e r i mpl i e s, i t st e p s u p t h e i n pu t v ol t a g e w h i c h ma k e s t h e ou t p u t vol t a g e g r e a t e r t h a n t h e i n pu t v ol t a g e . T h e c on ve r t e r i s c on t r ol t h r ou g h t h e M O S F E T w h i c h a c t a s a sw i t c h . Th e O N a n d O F F of t h e sw i t c h ( M O S F E T) c o n t r ol s t h e ou t pu t vol t a g e b y c h a n g i n g t h e v ol t a g e of t h e i n d u c t a n c e s o a s t o e n a b l e t h e ph ot ov ol t a i c m od u l e pow e r t h e l oa d a t ma x i mu m vol t a g e . Th e o pe r a t i o n of t h e c on ve r t e r i s a n a l y z e d i n d i f f e r e n t ope r a t i n g c o n d i t i on . Th e o pe r a t i on of t h e c on ve r t e r i s a n a l y si s i n c on t i n u ou s c on d u c t i on m od e .

IJSER © 2012

http://www.ijser.org

The research paper published by IJSER journal is about Design of Dc-Dc Converter with Maximum Power Point Tracker Using Pulse Generating (555 Timers) Circuit for Photovoltaic Module 3

ISSN 2229-5518


D i vi d i n g b ot h si d e s of e q u a t i on ( 1 ) b y T s a n d r e a r r a n g i n g t e r m s y i e l d t h e t r a n sf e r f u n c t i on of
t h e c on ve r t e r . S e e t r a n sf e r f u n c t i on of t h e c on ve r t e r i n e q u a t i on ( 2 )

( 2 ) [ 9 ]

A n d e q u a t i on ( 2 ) c on f i r m s t h a t t h e ou t pu t v ol t a g e i s g r e a t e r t h a n t h e i n pu t .
A s su mi n g a l o s se s c i r c u i t , P d = Po ,

F i g u r e 1 S t e p u p d c - d c c o n v e r t e r [ 9 ] .

3.11 CONT INUOUS CONDUCT ION M ODE (CCM ):

I n c on t i n u ou s c on d u c t i on m od e t h e i n d u c t a n c e c u r r e n t f l ow s c on t i n u ou s [ i L ( t ) > 0 ] a s i l l u st r a t e d w i t h t h e st e a d y st a t e w a ve f or m b e l ow i n f i g u r e 2 .
Th e r e f or e V d I d = V o I o


A n d
( 3 ) [ 9 ]
Th e t i me i n t e g r a l of t h e i n d u c t or vol t a g e o ve r o n e t i me pe r i od mu st b e z e r o i n st e a d y st a t e .
V d t on + (V d – Vo )t o f f =0 ( 1 )
W h e n t h e sw i t c h ( M O S F E T ) i s t u r n e d O N , t h e d i od e i s r e ve r se b i a se d , t h u s d i sc on n e c t i n g t h e ou t pu t st a g e . Th e i n pu t t h e n d e l i ve r s e n e r g y t o t h e i n d u c t or . W h e n t h e s w i t c h ( M O S F E T) i s t u r n e d O F F , t h e ou t pu t st a g e i s n ow r e c on n e c t e d a n d r e c e i ve s e n e r g y f r o m t h e i n d u c t or a s w e l l f r om t h e i n pu t . I n t h e st e a d y st a t e a n a l y si s pr e se n t e d h e r e , t h e ou t pu t f i l t e r c a pa c i t or i s a s su me d t o b e ve r y l a r g e t o e n su r e a c o n s t a n t ou t pu t vol t a g e V o ( t ) ~ V o [ 9 ] .

F i g u r e 2 . 0 E q u i v a l e n t C i r c u i t f o r b o o s t c o n v e r t e r i n c o n t i n u o u s c o n d u c t i o n m o d e ( C C M ) ; ( a) s w i t c h O N ; ( b ) s w i t c h O F F .

4 M AXIM UM POWER POINT T R ACKER

(M PPT ):

A ma x i mu m p ow e r p oi n t t r a c k e r i s a h i g h - e f f i c i e n c y D C - D C c on ve r t e r , w h i c h f u n c t i on s a s a n o pt i ma l e l e c t r i c a l l oa d f or ph ot ov ol t a i c c e l l , mo st c om m on l y u se d f or a s ol a r pa n e l or a r r a y a n d c on ve r t s t h e p ow e r t o a v ol t a g e or c u r r e n t l e ve l w h i c h i s m or e su i t a b l e t o w h a t e ve r l oa d t h e sy st e m i s d e si g n t o d r i ve . P V c e l l s h a ve a si n g l e o pe r a t i n g poi n t w h e r e t h e va l u e s of c u r r e n t a n d vol t a g e r e su l t i n a ma x i mu m p ow e r ou t pu t f or t h e c e l l [ 1 0 ] . M ax i mu m po w e r p oi n t t r a c k e r ( M P P T) i s b a si c a l l y a n e l e c t r on i c sy st e m t h a t c o n t r ol s t h e d u t y c i r c ui t of t h e c on ve r t e r t o e n a b l e t h e ph ot ov ol t a i c mo d u l e o pe r a t e a t ma x i mu m o pe r a t i n g p ow e r a t a l l c on d i t i on a n d n ot s o me s o r t of me c h a n i c a l tr a c k i n g sy st e m t h a t ph y si c a l l y r ot a t e t h e ph ot o v ol t a i c mod u l e s t o f a c e su n l i g h t d i r e c t l y . Th e a d va n t a g e s of M P P T r e g u l a t or s a r e g r e a t e st d u r i n g c l ou d y or h a z y d a y s, c ol d w e a t h e r or w h e n t h e b a t t e r y i s d e e pl y d i sc h a r g e d . Th e r e a r e d i f f e r e n t t y pe s of ma x i mu m po w e r p oi n t t r a c k e r me t h od s d e ve l o pe d o ve r t h e y e a r s a n d t h e y a r e l i st e d b e l ow a s f ol l ow s ( 1 ) P e r t u r b a n d ob se r ve me t h od , ( 2 ) I n c r e me n t a l c on d u c t a n c e me t h od , ( 3 ) A r t i f ic i al n e u t r a l n e t w or k me t h o d , ( 4 ) F u z z y l og i c me t h o d , ( 5 ) P e a k p ow e r p oi n t me t h o d , ( 6 ) O pe n c i r c u i t vol t a g e me t h od , a n d ( 7 ) Te mp e r a t u r e me t h od e t c . Th e M P P T pl a y s a ve r y si g n i f i c a n t r ol e b e c a u se w i t h ou t t h e M P P T t h e d e si r e ou t pu t e l e c t r i c a l pow e r w i l l n ot b e a c h i eve w i t h c h a n g i n g w e a t h e r c on d i t i on s. T h e a d opt e d

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The research paper published by IJSER journal is about Design of Dc-Dc Converter with Maximum Power Point Tracker Using Pulse Generating (555 Timers) Circuit for Photovoltaic Module 4

ISSN 2229-5518

t o pol og y f or t h e M P P T d e si g n w i l l c o m pr i se f o u r pa r t s, n a me l y M i c r oc on t r ol l e r , pu l s e g e n e r a t or
( 5 5 5 Ti me r C i r c u i t ) a n d a G a t e w h i c h ac t a s a b u f f er .

5 M ETHODOLOGY AND DES IGN:

5.1 SY ST EM BLOCK DIAGR AM INCLUDING M PPT and DC -DC BOOST CONVERT ER:

F i g u r e 3 s ys t e m b l oc k d i a g r a m

F r o m t h e b l oc k d i a g r a m a b ove , t h e D C - D C c on ve r t e r i s u se d a s a ph ot o vol t a i c i n t e r f ac e b e t w e e n t h e ph ot ov ol t a i c m od u l e a n d t h e l oa d t o p ow e r t h e l oa d ( L e d b a se l i g h t , 2 4 V ) . Th i s i s a c h i e ve d b y c on t r ol l i n g t h e d u t y c y c l e of t h e DC - D C b oo st c on ve r t e r . F r o m f i g u r e 3 , t h e mi c r oc on t r ol l e r t e n d t o ma x i mi z e t h e ou t p u t p ow e r f r om t h e ph ot o v ol t a i c mod u l e b y a d j u st i n g t h e d u t y c y c l e s o t h a t t h e ph ot ov ol t a i c m od u l e w i l l a l w a y s b e a t i t s ma x i mu m p ow e r a t a l l t i m e s. Th i s i s d on e b y c on t i n u ou sl y c ol l e c t i n g sa m pl e s of vol t a g e a n d c u r r e n t f r o m t h e ou t pu t of t h e ph ot ov ol t a i c mo d u l e i n c l u d i n g a r ef e r e n c e vol t a g e f r om t h e ou t pu t of t h e c on ve r t e r a s sh ow n i n f i g u r e 3 a n d e mpl oy i n g t h e mi c r oc on t r ol l e r t o i n c r e a se or d e c r e a se t h e v ol t a g e a p pl i e d t o t h e pu l s e g e n e r a t or ( P W M ) i n or d e r t o c h a n g e t h e d u t y c y c l e of t h e c on ve r t e r .

6 PHOT OVOLT AIC L ABOR AT ORY T EST RESULT S:

Th e d e si g n of t h e D C - D C c on v e r t e r r e q u i r e s i n p u t p ow e r w h i c h w i l l b e ob t a i n e d f r o m a ph ot ov ol t a i c m od u l e . Th e po w e r w i l l b e d e f i n e b y t h e I - V a n d P - V c h a r a c t e r i st i c c u r ve a s i l l u st r a t e d i n f i g u r e 5. 0 a n d 6 . 0 . To d e t e r mi n e t h e se c h a r a c t e r i st i c c u r ve s, t h e ph ot o v ol t a i c m od u l e w i t h g i ve n s pe c i f i c a t i on s w a s t e st e d i n t h e l a b . S e e s pe c i f i c a t i on i n t a b l e 1 .
Th e t e st w a s d on e i n t h e l a b or a t or y u si n g l a b se t u p sh ow n b e l ow i n f i g u r e 4 , t o a c h i e ve t h e
i n pu t v ol t a g e a n d c u r r e n t of t h e D C - D C c on ve r t e r . Th e t e st w a s d on e w i t h r a d i a t i on of 1 0 0 0 W / m2 a n d w i t h va r i a t i on of l oa d r e si st a n c e u si n g oh m’ s l a w ( V = I R ) , t o d e t e r mi n e t h e i n pu t vol t a g e a n d c u r r e n t . A l so 6 6 0 W / m 2 , 3 7 0 W / m2 w e r e a l so u se d t o a sc e r t a i n t h e va r i a t i on of p ow e r w h e n r a d i a t i on i s c h a n g e .

F i g u r e 4 , l a b o r a t o r y s e t u p f o r p h o t o v o l t a i c m o d u l e

F r o m f i g u r e 5 , e a c h n u mb e r r e pr e se n t d i f f e r e n t c om p on e n t i n t h e se t u p a n d t h e y a r e 1 : h a l o g e n l a m p, 2 : P y r a n o me t e r , 3 : P h ot ov ol t a i c m od u l e , 4 : A m me t e r , 5 , 6 : V ol t me t e r s a n d 7 : l oa d ( r h e o st a t ) .
Ta b l e 2 ; r e pr e se n t t h e l a b or a t or y t e st r e s u l t s of t h e ph ot ov ol t a i c m od u l e a t d i f f e r e n t i r r a d i a ti on . A l s o F i g u r e 5 a n d 6 d e m on st r a t e t h e p ow e r , v ol t a g e a n d c u r r e n t a t ma x i mu m p ow e r poi n t w h i c h i l l u st r a t e t h e c h a n g e s i n ma x i mu m ou t pu t p ow e r of t h e m od u l e w h e n r a d i a t i on c h a n g e s. I n t h e l a b or a t o r y t e st , a h a l o g e n l a m p i s u se a s su n r a y a n d a py r a n o me t e r , t o me a su r e i r r a d i a t i on a t d if f e r en t l e ve l . Th e py r a n o me t e r ou t pu t i s l i n e a r , 0 . 2 m V pe r W / m2 . A t st a n d a r d t e st c on d i t i on ( S T C ) , t h e ph ot ov ol t a i c mo d u l e pa r a me t e r s a r e sh o w n i n t h e t e c h n i c a l d a t a sh e e t i n t a b l e 1 . Th e ou t pu t p ow e r of t h e l a b or a t or y t e st r e su l t a t 1 0 0 0 W / m 2 w a s q u i t e d i f f er e n t t o t h a t of t h e t e c h n i c a l d a t a sh e e t of t h e ph ot ov ol t a i c mod u l e d u e t o t h e f a c t t h a t th e e x pe r i me n t w a s d on e i n d o or w i t h a h a l og e n l a m p w h i c h a f f e c t e d t h e i n t e n si t y of t h e r a d i a t i on on t h e m od u l e .

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The research paper published by IJSER journal is about Design of Dc-Dc Converter with Maximum Power Point Tracker Using Pulse Generating (555 Timers) Circuit for Photovoltaic Module 5

ISSN 2229-5518

2.5

PV CHARACTERISTIC CURVE

T a b l e 1 : T ec h n i c a l d a t a s h e e t of p h o t o v o l t a i c m o d u l e

Pmpp

2

1.5

1000W/m2

660W/m2

370W/m2

MPP


T a b l e 2 : p h o t o v o l t a i c m o d u l e t e s t r es u l t a t d i f f er e n t r a d i a t i o n .

IV CHARACTERISTICS CURVE

0.2

1

0.5

0

F i g u r e 6 , P - V C u r v e a t d i f f e r e n t i r r a d i a t i o n l e v e l .

7 DC - DC BOOST CONVERT ER DESIGN AND RESULT AN ALY SIS:

A s st a t e d a b o ve t h a t D C - D C b o o st c on ve r t e r i s u se d a s ph ot ov ol t a i c i n t e r f ac e a n d i s d e si g n t o b oo st t h e ou t pu t v ol t a g e t o 2 4 V t o me e t t h e r e q u i r e me n t of t h e l oa d ( l e d b a se l i g h t ) . B a se d on t h i s f a c t s o me s pe c i f i c a t i on of t h e b o o st c o n ve r t e r w a s a s su me d t o me e t t h e l oa d d e ma n d , se e t a b l e 3 a n d b oo st c on ve r t e r d e si g n e q u a t i on s a s l i st e d i n e q u a t i on ( 5 ) , ( 6 ) ( 7 ) a n d ( 8 ) . E q u a t i on ( 1 ) r e pr e se n t t h e b o o st c on ve r t e r t r a n sf e r f u n c t i on w h e r e V o = ou t pu t v ol t a g e , V i = i n pu t vol t a g e a n d D r e pr e se n t
d u t y c y c l e . A l so F s = sw i t c h i n g f r e q u e n c y , L o = b oo st

Isc

Impp

0.15

0.1

0.05

0

MPP

1000W/m2

660W/m2

370W/m2

0 2 4 6 8 10 12 14 16 18 20


i n d u c t a n c e a n d C o r e pr e se n t ou t pu t c a pa c i t a n c e . ( 5 )
Δ I= ( 6 )
Δ V= ( 7 )
P i = P o = V i * I i = V o* I o ( A s su me 1 0 0 % e f f i c i e n c y of c on ve r t e r ) ( 8 )

voltage (V)

Vmpp Voc

F i g u r e 5 , I - V c h a r ac t er i s t i c c u r v e a t d i f f e r e n t i r r a d i a t i o n l e v e l

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The research paper published by IJSER journal is about Design of Dc-Dc Converter with Maximum Power Point Tracker Using Pulse Generating (555 Timers) Circuit for Photovoltaic Module 6

ISSN 2229-5518

current of photovoltaic

module at 1000W/m2)

Out put voltage

24

Volts

Voltage ripples (5%)

1.2

Volts

Current ripples (10%)

0.0159

Amps

Input power (output

power of photovoltaic module at 1000W/m2)

2.55

Watts

Switching frequency

20000

Hertz

T a b l e 3 : d e s i g n s p ec i f i c at i o n s .

W i t h t h e se e q u a t i on s a b o ve , I o, L , C a n d D w e r e c a l c u la t e d a n d l i st e d i n Ta b l e 4 u si n g r e si st i ve l oa d ( 2 2 5 . 6 Ω ) . S e e a p pl i c a t i on of c a l c u l a t e d va l u e s i n f i g ur e 8 w i t h si mu l a t i on r e su l t s i n f i g 9 –f i g 1 4 u si n g P s pi c e . I t i s a l s o u se f u l t o a d j u st t h e va l u e s of e a c h c o m p on e n t i n c l u d i n g t h e d u t y c y c l e t o a c h i e ve t h e r e q u i r e d r e su l t .

CALCULATED

VALUE

UNIT

Duty cycle, D

33

Percent

Load resistance, Ro

225

Ohms

Output current, Io

0.1064

Amps

Inductance, L

16.5

Henry

Capacitor, C

1.463µ

Farad

T a b l e 4 : d e s i g n c a l c u l a t i o n

F i g u r e 7 D C - D C b o o s t c o n v e r t e r s i m u l a t i o n s C i r c u i t .

F i g u r e 8 O u t p u t v o l t a g e o f b o o s t c o n v e r t e r .

F i g u r e 9 : o u t p u t v o l t a g e r i p p l e , ∆ V

F i g u r e 1 0 : i n d u c t a n c e c u r r e n t r i p p l e

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8. PULSE GENER AT OR CIRCUIT :

F i g u r e 1 1 : i n d u c t a n c e c u r r e n t ( L 1 ) , c a p a c i t a n c e c u r r e n t

( C 3 ) a n d d i o d e c u r r e n t ( D 1 )

F i g u r e 1 3 : M O S F E T O N a n d O F F t i m e , ( s wi t c h i n g c u r r e n t )

F i g u r e 1 3 c o n v e r t e r s i m u l a t i o n d u t y c y c l e a t 3 3 % ( PW M )

To e n a b l e t ot a l c on t r ol of t h e ma x i mu m p ow e r p oi n t of t h e ph ot ov ol t a i c m od u l e , t h e p ow e r M O S F E T ( sw i t c h ) of t h e b o o st c on ve r t e r mu st b e sw i t c h i n g O N a n d O F F a s f a st a s p o s si b l e t o a v oi d sa t u r a t i on of t h e i n d u c t or . Th e ve r i f i c a t i on of t h e r e s po n s e of t h e d e si g n D C - D C c on ve r t e r h a s b e e n d on e f r o m t h e a b ove si mu l a t i on r e su l t s a n d i n ove r a l l i t pr ove s t h a t t h e c on ve r t e r w or k s w e l l a n d c a n b e u se d a s ph ot ov ol t a i c i n t e r f ac e .
P u l se g e n e r a t or c i r c u i t ( P W M ) i s on e of t h e ma j or c om p on e n t i n t h e pr o po se M P P T d e si g n i n t h e
pr oj e c t b e c a u s e c on t i n u ou s c h a n g i n g of t h e d u t y c y c l e d e t e r mi n e s t h e st e a d y st a t e ou t pu t vol t a g e of t h e b o o st c on ve r t e r w i t h r e g a r d s t o t h e i n p u t vol t a g e . I n t h i s pa pe r , a n a st a b l e mu l t i vi b r a t or ( 5 5 5 t i me r c i r c ui t ) , a c u rr e n t sou r c e a n d t h e ou t p u t vol t a g e of t h e mi c r oc on t r ol l e r a r e u se d t o pr od u c e t h e pu l se w a ve m o d u l a t i on ( P W M ) / d u t y c y c l e .

9. M ICROCONT ROLLER:

Th e mi c r oc on t r ol l e r pl a y s a n i m p or t a n t r ol e i n c h a n g i n g t h e d u t y c y c l e of t h e b o o st c on ve r t e r b y se n d i n g D C v ol t a g e t o t h e pu l se g e n e r a t i n g c i r c ui t a f t e r c a lc u l a t i n g a n d c o m pa r i n g t h e ma x i mu m p ow e r s of t h e ph ot ov ol t a i c m od u l e a n d r e f e r e n c e ou t pu t vol t a g e of t h e c on ve r t e r a t d i f f e r e n t i n t e r va l s. Th e mi c r oc on t r ol l e r ope r a t i on w i l l b e b a se d on t h e f l ow c h a r t . Th e mi c r oc on t r ol l e r w a s n ot a p pl i e d b u t w h e n t e st i n g t h e d e si g n sy st e m a vol t a g e s ou r c e w a s u se d i n pl a c e of t h e c on t r ol l e r t o c h a n g e t h e d u t y c y c l e w h e n t h e ou t pu t of t h e ph ot ov ol t a i c mo d u l e ( v ol t a g e s ou r c e ) w a s a l t e r e d t o a c h i e ve ou r d e si r e d ou t pu t .

10. IM PLEM ENT AT ION:

11. FULL SCHEM AT IC O F PRO POSE DESIGN:

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F i g u r e 1 4 s c h e m a t i c of p r o p o s e s ys t e m d i a g r a m

12. IM PLEM ENT AT ION RESULT S AN D DISCUSION:

Th e d e si g n w a s i m pl e me n t e d w i t h t h e se l e c t e d pa r t s a n d u si n g a vol t a g e s ou r c e t o r e pr e se n t t h e P i c mi c r oc on t r ol l e r a s sh ow n i n f i g u r e 1 5 . A s t h e i n pu t v ol t a g e r e pr e se n t i n g t h e ph ot ov ol t a i c m od u l e c h a n g e s t h e r e i s a c or r e s po n d i n g c h a n g e i n ou t pu t v ol t a g e t h e n t h e v ol t a g e sou r c e r e pr e s e n t i n g t h e P i c mi c r oc on t r ol l e r i s a l t e r e d t o c h a n g e t h e d u t y c y c l e s o a s t o i n c r e a se t h e ou t p u t vol t a g e t o t h e d e si r e d va l u e . S e e r e su l t s f or ph ot ov ol t a i c ou t pu t of 1 5 . 9 V , 1 4 . 2 V a n d 1 3 . 6 V w i t h d u t y c y c l e of 3 1 % , 3 9% a n d 4 3 % r e spe c t i ve l y .

F i g u r e 1 5 I m p l e m e n t e d s ys t e m d i a g r a m w i t h s e l e c t e d p a r t s .

F i g u r e 1 6 O u t p u t v o l t a g e of b o o s t c o n v e r t e r ( 2 3 . 8 V ) a n d d u t y c yc l e ( 3 3 . 6 % ) a t M O S F E T g a t e .

Th e si mu l a t i o n r e su l t s of f i g u r e ( 8 ) a n d ( 1 3 ) of t h e t h e or e t i c a l d e si g n c on ve r t e r ma t c h e s w i t h t h e r e su l t of t h e pr a c t i c a l a ppl i c a t i on of t h e b oo st c on ve r t e r t h a t i s, 3 3 % d u t y c y c l e a n d ou t p u t vol t a g e of 2 4 V w i t h a n i n pu t v ol t a g e of 1 5 . 9 V r e pr e s e n t i n g t h e ou t pu t of p h ot o vol t a i c m od u l e . A

d i f f er e n t w a s ob se r ve i n pe a k t o pe a k vol t a g e of P W M si g n a l w i t h t h e si mu l a t i o n h a vi n g a v ol t a g e of 1 6 V pe a k t o pe a k w h i l e t h e pr a c t i c a l a ppl i c a t ion h a s 6 . 5 6 V w h i c h i s a s a r e su l t of t h e va l u e of r e si st a n c e c on n e c t e d t o t h e i n pu t of t h e M O S F E T t o i n c r e a se t h e M O S F E T g a t e c u r r e n t ( I D ) w h i c h i s d i f f er e n t f or b ot h c a se s. Th e ou t pu t v ol t a g e a n d d u t y c y c l e w h e n a 1 5 . 9 V i s a p pl i e d f r o m t h e ph ot ov ol t a i c mod u l e w a s a c h i e ve d w i t h a vol t a g e of 3 . 4 V ( vol t a g e s ou r c e ) a s su me t o b e g e n e r a t e d b y t h e mi c r oc on t r ol l e r . Th e pr a c t i c a l i mpl e me n t a t i on al so c on f i r m s t h e t r a n sf e r f u n c t i on e q u a ti on of b oo st c on v e r t e r ( ) .

F i g u r e 1 7 o u t p u t v o l t a g e r i p p l e

Th e c a pa c i t or of t h e b o os t c on ve r t e r d e t e r mi n e s t h e v ol t a g e r i p pl e of t h e ou t pu t vol t a g e b u t d o e s n ot h a ve a n y si g n i f i c a n t i mpa c t o n t h e ma g n i t u d e of t h e ou t pu t v ol t a g e . I n t h e t h e or e t i c a l c a l c ul a t ion a vol t a g e r i p pl e of 1 . 2 V w a s e st i ma t e d u si n g a s ma l l e r c a pa c i t or a s i l l u st r a t e d i n f i g u r e 9 , b u t d u r i n g t h e pr a c t i c a l i mpl e me n t a t i o n a b i g g e r c a pa c i t a n c e ( 4 . 7 u ) w a s u se w h i c h a f f e c t e d th e vol t a g e r i ppl e t o 1 . 6 V a s sh ow n a b o ve i n f i g u r e 1 7 b u t i t d oe s n ot c h a n g e t h e ou t pu t v ol t a g e of 2 4 V . i t w a s a c c e pt e d b e c a u se i t su i t a b l e w i t h o u r pr e se n t l oa d v ol t a g e ( L e d b a se l i g h t , n o mi n a l vol t a g e of 2 4 V ) . Th e r e su l t sh ow s t h a t w h e n t h e ou t pu t of t h e ph o t ov ol t a i c m od u l e c h a n g e s t h e d e si g n b oo st c o n ve r t e r i s c a pa b l e of b o o st i n g t h e p ow e r t o ma x i mu m p ow e r w i t h a c h a n g e o n t h e d u t y c y c l e .

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The research paper published by IJSER journal is about Design of Dc-Dc Converter with Maximum Power Point Tracker Using Pulse Generating (555 Timers) Circuit for Photovoltaic Module 9

ISSN 2229-5518



w h i c h a g r e e w i t h b oo st c on ve r t e r t r a n sf e r f u n c t ion e q u a t i on ( ).

C O N C L U S I O N A N D F U R T H ER W OR K S :

F i g u r e 1 8 o u t p u t v o l t a g e o f b o o s t w h e n i n p u t v o l t a g e i s

1 4 . 2 V a n d d u t y c y c l e i s 3 9 % a n d i n p u t c u r r e n t 0 . 2 8 A wi t h

o u t p u t v o l t a g e o f m i c r o c o n t r o l l e r as 3 . 2 V .


F i g u r e 1 8 r e pr e se n t t h e ou t pu t vol t a g e a n d d u t y c y c l e ( P W M ) w h e n a 1 4 . 2 V i s a p pl i e d a t t h e i n p u t of t h e b oo st c on ve r t e r . Th e ou t pu t vol t a g e t e n d s t o me e t a ve r a g e v ol t a g e of 2 3 . 6 V w h e n t h e mi c r oc on t r ol l e r ( a s su me v ol t a g e s ou r c e ) w a s a l t e r e d t o 3 . 2 V , t h i s a c t i on c h a n g e s t h e d u t y c y c l e t o 3 9 % w h i c h i s a l m o st e q u a l w i t h t h e c a l c u l a t e d va l u e of 4 0 % u si n g t h e b oo st t r a n sf e r f u n c t ion e q u a t i on ( ) .

F i g u r e 1 9 o u t p u t of b o o s t c o n v e r t e r w h e n i n p u t v o l t a g e i s

1 3 . 6 V a n d d u t y c yc l e i s 4 3 % a n d i n p u t c u r r e n t 0 . 3 A w i t h o u t p u t v o l t a g e o f m i c r o c o n t r o l l e r as 3 . 0 V .

F i g u r e 1 9 r e pr e se n t t h e ou t pu t v ol t a g e of t h e b o o st c on ve r t e r a n d d u t y c y c l e w h e n 1 3 . 6 V w a s a p pl i e d a s t h e i n pu t v ol t a g e ( ou t pu t of ph ot ov ol t a i c m od u l e ) of t h e c on ve r t e r . Th e ou t pu t vol t a g e w a s
2 3 . 9 V d u e t o t h e c h a n g e of ou t pu t v ol t a g e of
mi c r oc on t r ol l e r ( vol t a g e s ou r c e ) t o a b ou t 3 . 0 V . t h i s a c t i on t e n d t o a d j u s t t h e d u t y c y c l e t o 4 3 . 8%

REFERENCES

Th e a i m of t h e pa pe r i s t o d e si g n a D C b oo st
c on ve r t e r a n d a M a x i mu m p ow e r p oi n t t r a c k e r t o o pt i mi z e e f f i c i e n c y a t al l t i me s. Th i s w a s d o n e t h r ou g h c a r e f u l ex a mi n a t i on of t h e ph ot ov ol t a i c m od u l e d a t a sh e e t t o a c h i e v e a mo st d e si r a b l e ou t c o me , pa r t i c u l a r l y wi t h ma x i mu m p ow e r . T h e d e si g n w a s f i r st c a r r i e d ou t t h r ou g h a c a r e f u ll y d e si g n sc h e ma t i c s of t h e sy st e m. Th e d e si g n of t h e DC - D C b o o st c on ve r t e r , pu l se g e n e r a t or ( P W M ) f or t h e pr oj e c t w a s su c c e s sf u l l y c om pl e t e d b u t a n a u t o ma t e d ma x i mu m po w e r p oi n t t r a c k e r w a s n ot su c c e s sf u l l y a c h i e ve d a n d w i l l b e l o ok a t se pa r a t e l y . Th e pr a c t i c a l i mpl e me n t a t i on t e st i n g e x pl a i n s t h e b e h a vi or of t h e mo d u l e d u r i n g d i f f er e n t i r r a d ia t i on a n d a l so t o ob se r ve pr a c t i ca l c on t r ol of t h e M P P T. Th e D C b o o st c on ve r t e r s o pe r a t i n g i n c on t i n u ou s c on d u c t i on mo d e s w i t h ma x i mu m p ow e r p oi n t t r a c k e r s h a ve b e e n s t u d i e d a n d pr o po se d .
N e x t st e p s w i l l b e :

A s si g n a mi c r oc on t r ol l e r

D e ve l o p M P P T A l g or i t h m/ F l ow c h a r t a n d o pe r a t i on .

I mpl e me n t a t i on on t h e pr o po se d d e si g n .

ACKNOWLEDGEMENT

I am grateful to Dr Author Williams for his immerse contributions towards the success of this work and also the University of Nottingham for using the school of electrical and electronic laboratory.
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The research paper published by IJSER journal is about Design of Dc-Dc Converter with Maximum Power Point Tracker Using Pulse Generating (555 Timers) Circuit for Photovoltaic Module 10

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