UG - Mini Project - Solar Lightning System

7/25/2019 UG - Mini Project - Solar Lightning System

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Solar Lighting Systems

A

MINI PROJECT REPORT

ON

SOLAR LIGHTING SYSTEM

The project is done and s!mitted "or the "l"illment o" the

A#ard o" the degree

BACHELOR OF TECHNOLOGY

IN

Electronics and Communication Engineering

Under the Guidance of

Mr GANE!H

B"#

A$ITYA B %&'(F)A&*&+,

B NARE!H %&'(F)A&*&',

G NARE!H %&'(F)A&*)&,

- RA.I TEJA RE$$Y%&'(F)A&*)',

Electronics $ %ommnication Engineering &'(ITS)

*


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DEPARTMENT OF ELECTRONICS AND COMMUNICATION

ENGINEERING

Certifcate

This is to certi"y that the project report title +!OLAR LIGHTING !Y!TEM, is !eing s!mitted

/" A$ITYA B %&'(F)A&*&+,0 B NARE!H %&'(F)A&*&',0 G NARE!H %&'(F)A&*)&,0 -

RA.I TEJA RE$$Y %&'(F)A&*)', in partial "l"illment o" the a#ard o" (achelor o"

Technology in Electronics and %ommnication Engineering- to 'ish#a (harathi Institte O"

Technology $ Sciences is a record o" !ona"ide #or. carried ot !y them nder my gidance and

sper/ision0

The reslts presented in this project ha/e !een /eri"ied and are "ond to !e satis"actory0

They ha/e not !een s!mitted to any other 1ni/ersity "or the a#ard o" any degree or diploma

p to my .no#ledge

E1TERNAL GUI$E PROJECT GUI$E HEA$ OF THE $EPARTMENT

Mr GANE!H Mr CA!HO- .I!HNU

HEA$ OF THE IN!TITUTION

$r $Mahe23ar Redd"


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AC-NO4LE$GEMENT

Sel" %on"idence- hard #or.- commitment and planning are essential to carry ot any

tas.0 3ossessing these 4alities is sheer #aste- i" an opportnity does not e5ist0 So- #e #hole

heartedly than. Mr %0ASHO6 'ISHN1 Head o" The 7epartment- Electronics and

Communication Engineering "or his encoraging spport and gidance in carrying ot the

project0

8e than. or project gide- Mr0 GANESH "or pro/iding s #ith an e5cellent project

and giding s in completing or project sccess"lly0

8e #old also li.e to e5press or sincere than.s to all the sta"" o" E%E 7epartment- '(ITS

"or their .ind cooperation and timely help dring the corse o" or project0 9inally- #e #old

li.e to than. or parents and "riends #ho ha/e al#ays stood #ith s #hene/er #e #ere in need

o" them0

Sincerely-

A$ITYA B %&'(F)A&*&+,

B NARE!H %&'(F)A&*&',

G NARE!H %&'(F)A&*)&,

- RA.I TEJA RE$$Y%&'(F)A&*)',


:


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!OLAR LIGHTING !Y!TEM

CONTENT!

) AB!TRACT )

+ INTRO$UCTION +

5 BLOC- $IAGRAM AN$ IT! $E!CRIPTION

*

a SOLAR 3ANEL ;

/ '0%0Of MAIN O1T31T TRANS9ORMER )&

* CIRCUIT $IAGRAM AN$ IT! $E!CRIPTION ))

a INTEGRATE7 38M %ONTROLLER *2

/ 9EAT1RES O9 38M %ONTROLLER *?

c %IR%1IT 7IAGRAM O9 38M OS%ILLATOR *' nder

the !right Sn- and i" the !attery is charged #ith this /oltage it may spoil de to e5cess /oltage

charging0 There !y the panel otpt is reglated $ the !attery is charged #ith a constant /oltage

sorce o" *:0;'0 The detailed description o" the po#er sorce is descri!ed in "ollo#ing chapters0

+ BLOC- $IAGRAM AN$ IT! $E!CRIPTION


**


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Fi9ure )

The !loc. diagram and its description o" the project #or. ;!o


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The solar panel sed in this project #or. is designed to deli/er a ma5imm /oltage o" *>

nder the !right SnJ this is .no#n as no load /oltage- #hen it is loaded- the /oltage may "all

do#n according to the load applied to the panel0 As per the ratings speci"ied !y the panel

man"actrer- #hen a *#atts load is connected across the panel terminals- then the /oltage may

"all do#n !y less then *:'0 This /oltage /aries according to the load applied to the panel0 As the

!attery consmes total po#er #hen it is in discharge condition- $ thogh the panel otpt is

reglated- the /oltage may "all do#n !y less then *:'- as the !attery is charging slo#ly- the

terminal /oltage le/el !oosts $ charging crrent #ill !e redced gradally0 As the charging

crrent redced- !attery terminal /oltage #ill !e increased- $ this /oltage reaches to a ma5imm

le/el o" *:0;'- !ecase panel ot pt is reglated !y *:0;'0 As the panel ot pt #ill not e5ceeds

!eyond *:0;'- the !attery #ill !e charged #ith this constant /oltage0

5+ .CO

As descri!ed a!o/e- the panel /oltage is not sta!le- it /aries !ased on many "actors- the

"irst reason is a/aila!ility o" solar energy- this is the inpt sorce to the solar panel- and i" this

sorce is /aried- accordingly panel otpt also /aries0 The second reason is that the panel /oltage

/aries according to the load applied to it0 (ased on these t#o reasons- the panel otpt as it is can

not !e sed "or charging0 There"ore here sing a /oltage reglator circit- panel otpt is

reglated at *:0;'0 Means nder any condition &thogh the panel is e5posed to the !right Sn)-

the panel "inal otpt /oltage #ill not e5ceeds more then *:0;'0 This reglated sorce is sed to

charge the !attery0 As the !attery is charged #ith constant /oltage sorce- the li"e o" the !attery

can !e increased0

55 BATTERY

The !attery sed here is rated "or *2' at @0; AH &Ampere Hor)- since lo# po#er panel

is sed- the !attery #ill ta.e lot o" time to charge "lly0 As the panel generates 0=Amps nder

!right sn- the charging time is de"ined as- !attery rating- i0e0 @0;AH charging crrent- i0e0

0=Amps K >0: hors appro5imately0 I" the !attery is charged #ith high po#er panel- charging

time can !e redced0 As the solar po#er is nBsta!le- the panel may not prodce continos

otpt- the po#er otpt may /ary incidentally- there !y a/erage po#er #ill !e al#ays less


*:


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then the rating0 There !y it is recommended to se high po#er panels "or charging the higher

rating !atteries0 As it is a prototype modle- here less po#er !attery is sed0

The !attery !ac.Bp time can !e de"ined as !attery rating consmed energy !y the

system0 The system designed here generates 0:Amps at 22' otpt- i0e0 the po#er otpt is

are made o" silicon0 A nm!er o" solar cells

electrically connected to each other and monted in a single spport strctre or "rame is called a

photo/oltaic modle00

The !attery is charged #ith constant /oltage charger- this circit is designed #ith @=*;

three terminal /oltage reglator chip- as the reglator itsel" can not generate s""icient crrent-#ith the help o" a po#er transistor con"igred as series pass reglator- energy prodced !y the

panel is spplied to the !attery at constant /oltage0 The otpt o" the /oltage reglator is applied

to the transistor !aseJ the "inal otpt is ta.en "rom transistor emitter0 The reglator esta!lishes

the !ase /oltage "or the transistor- this /oltage is sta!ilied at *;'- !t the /oltage at the emitter

#ill !e a!ot 0@' less- and the di""erence #ill !ecome grater as the load crrent increases0 In

addition to the a!o/e loss- as this circit contains po#er diode connected in series #ith the

charging circit to pre/ent "rom "lo# o" re/erse crrent- another 0@' drop #ill !e occrred

across the diode jnction0 A"ter estimating these losses appro5imately- it is conclded that the

charging circit is generating nearly *:0;'- means "inally the /oltage applied to the !attery #ill

!e *:0;'0 I" the !attery is "lly discharged- then it #ill consme more po#er "rom the panel- in

this condition the /oltage may "all do#n !y less then *2'0 As the !attery is getting charged- the

/oltage le/el #ill !e !oosted slo#ly0 Once the !attery is charged "lly- the !attery terminal


*?


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/oltage #ill !ecome e4al to the charger /oltage- #hen !oth le/els are e4alJ !attery #ill not

consme energy "rom the panel0 As the panel generates /ery less energy o" 0=Amps- $ #here as

the transistor can #ith standp to =Amps- heat sin. is not re4ired0 The reglator sed here can

generate s""icient !ase crrent- there !y the transistor allo#s ma5imm load crrent throgh its

jnction- i0e0 !et#een collector and emitter0 The !attery sed in this project #or. is .no#n as

lead acid type o" rechargea!le !attery- these !atteries are spposed to !e charged #ith constant

/oltage chargers0 7ring charging condition- thogh the !attery is "lly charged- the !attery

terminal /oltage shold not e5ceed more then *:0;'- other#ise it may damage de to the e5cess

/oltage charging0

The po#er 3 prodced !y the panel can !e calclated easily- initially the !attery that

consmes energy "rom the panel "or storing in to it is denoted as prodct o" the /oltage $ crrent&E $ I)0 Ths P ? E 1 I#atts- i" E is in /olts and I in amperes- and the /oltage across the !attery

terminals can !e measred #ith a /olt meter- similarly crrent can !e measred #ith an ammeter

connected in series #ith the load0 9inally the po#er is calclated in #atts !y mltiplying /oltage

$ crrents prodced !y the panel0 I" the /ale o" the load resistance &!attery terminal resistance)

RL is .no#n in ohms- po#er in #atts can also !e calclated !y se o" the "ormla P ? I+ RLor P

? E+ @ RL0

This system designed #ith po#er mos"ets is aimed to generate 2:' ac "rom *2 ' dc-

since it is a prototype modle a lo# po#er system is designed #hich can deli/er a ma5imm

po#er o" arond @8atts0 Since the system consmes more po#er- the otpt o" the panel is not

s""icient to dri/e the system0 There"ore stored energy is sed to energie the load #hen re4ired0

5* $UEL IN.ERTE$ OUTPUT O!CILLATOR

The oscillator circit designed #ith :;2? chip can generate in/erted s4are plses

at t#o di""erent otpt pins o" the I%0 (ased on this signal- the dri/e stage is con"igred

in pshBpll mode o" operation0 This circit consisting o" t#o po#er mos"ets s#itches the

trans"ormer alternati/elyJ there !y continos otpt can !e o!tained "rom the

trans"ormer secondary0 The ad/antage o" generating del in/erted otpts is that the

trans"ormer primary remains in energied condition continosly0 As this trans"ormer


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primary is ha/ing centre tap- it is di/ided in to t#o e4al sections- and !oth sections are

energied continosly one a"ter another0 In this regard s#itching losses can !e

minimied0

The otpt /oltage o" the singleBphase in/erter is roghly s4are #a/e and it can !e

controlled !y means o" plse #idth Modlation0 38M techni4e is a control #ithin the

in/erter and is also .no#n as /aria!le dty cycle reglation0 This method o" reglation

employs /ariation o" the condction time per cycle to alter the RMS otpt /oltage o" the

in/erter0 38M oscillator is constrcted sing I% :;2?0 It consists o" !ilt in oscillator-

comparators- error ampli"iers and otpt control circitry0 In this I%- a ;' internal

reglator is also pro/ided0 Internally- "or the comparators one inpt is "ed #ith a sa#B

tooth /oltage and the other inpt is "ed #ith a "eed!ac. monitoring /oltage0 As this

in/erter is con"igred in open loop operation 38M techni4e is not implemented here-

there !y otpt /oltage is not reglated0 The otpt /oltage #ill !e /aried according to

the load applied to the in/erter0 In or trail rns #e "ond that the system generates

arond 2?' in no load condition- #hen the system is connected #ith rated load o"

arond @ #atts- the /oltage is "allen do#n !y 22'0

56 $RI.ER !TAGE U!ING PO4ER MO!FET!

The dri/er stage designed #ith po#er mos"ets is con"igred as class ( mode o"

pshBpll ampli"ier0 The ad/antage o" class ( pshBpll ampli"iers are- it pro/ides linear

ampli"ication0 Apart "rom that the 7% collector crrent is less than the pea. A% crrent0

Ths- less collector dissipation reslts and the e""iciency increases0 In the project #or.-

center tapped trans"ormer is sed- #hich spplies t#o !ase crrents o" e4al amplitdes

!t *=ot o" phase0 There !y in the "irst hal" cycle one MOS9ET is o"" and the other

MOS9ET is condcting0 8hereas in the second hal" cycle other MOS9ET is condcting

i0e0- roles o" po#er MOS9ETS are re/ersed0 The crrent in the condcting MOS9ET

"lo#s throgh the pper hal" o" the primary #inding and the reslting time /arying "l5

in the trans"ormer core indce a /oltage in the secondary #inding0 The /oltage in trn


*


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prodces the "irst hal" cycle o" the crrent throgh the load0 Similarly- #hen the

MOS9ET roles are changing- the "l5 in the trans"ormer core in a direction opposite to

the "l5 o" pre/ios hal" cycle o" the load crrent0 The "inal crrent o" the load nder

these conditions is ths directly proportional to the signal crrent0 In practice the loadcrrent #old !e e5tremely distorted near the ero crossing0 This e""ect is called cross

o/er distortion and is de to GateBsorce /oltage in MOS9ET 'GS !eing ero #hen no

signal is applied0 Ho#e/er linear operation o" the &transistor) MOS9ET !egins only

#hen &!ase) Gate crrent is positi/e enogh to cross the ct in /oltage0 To eliminate the

distortion !aseBemitter jnction is !iased at appro5imately 0@'0 The reslt is class A(

rather than class ( operation !t is /ery close to class ( mode0 The !ias is called the

trnBon !ias in practice- one o"ten allo#s cross o/er distortion and relies on the

trans"ormer and internal and stray capacitors to "ilter it ot0

58 MAIN OUTPUT TRAN!FORMER

The main otpt trans"ormer sed in the dri/er stage is designed to deli/er 0:;

amps crrent at the secondary0 This is a step p trans"ormer and the primary o" this

trans"ormer is designed "or *2'0 This is a center tapped primary trans"ormer and the

primary is #onded #ith !yB"iller #inding- i0e0- the primary is #onded #ith t#o copperenameled #ires simltaneosly0 Starting o" the one #inding is cl!!ed #ith ending o"

another #ire to "orm a center tap0 The ad/antage o" adopting !yB"iller #inding concept at

primary side o" the trans"ormer is to maintain the accrate !alanceJ there !y the crrent

"lo#ing throgh !oth sections o" primary remains e4al0

* CIRCUIT $IAGRAM AN$ IT! $E!CRIPTION

The complete circit diagram sho#n at the end o" this chapter is e5plained in detail- as

the oscillator circit designed #ith SGS:;2? I% playing major roll- the description is


*@


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concentrated o/er internal strctre o" this de/ice0 Thogh the 38M techni4e is not

implemented here- it is e5plained #ell !ecase this de/ice o""ers good reglated otpt at lo#er

/oltages0 This I% is ha/ing *< pins #ith all !iltBin "eatres and this de/ice is sed "or #ide

/ariety o" applications li.e in/erters- con/erters- s#itch mode po#er spplies- etc0 The "ollo#ing

are the .ey points0

A) It o""ers #ide range "re4ency otptJ the "re4ency can !e adjsted "rom *H to ; 6H0 3in

nm!ers < $ @ are the "re4ency compensation pins- !y connecting a resistor $ capacitor

e5ternally to these pins- "re4ency can !e set to re4ired le/el0 Here the re4ired "re4ency is

;H- according to that the /ales o" RT $ %T &Resistor "or timing $ %apacitor "or timing) can

!e selected0 The capacitor is charged #ith constant crrent throgh a "i5ed resistor- there !y

reglated plse otpt can !e o!tained either "rom common emitters or common collectors0

() The preBdri/e stage !ilt in #ith the chip can a!le to spply a ma5imm crrent o" *;ma "rom

each otpt- hence additional preBampli"ier to dri/e the po#er stage is not re4ired0

%) As this chip is designed to generate del in/erted otpts- dri/e stage is con"igred in pshB

pll ampli"ier0 The ad/antage o" sing this ampli"ier is that the otpt trans"ormer remains in

energied condition continosly- there!y continos otpt can !e achie/ed "rom the system0

7) This chip o""ers ;' reglated otpt "rom pin nm!er *THpin-

this is a compensation pin0 8hen the system is s#itched on- the capacitor charges throgh

resistor- !ased on the /ales o" capacitor and resistor- the capacitor #ill ta.e some time to charge

"lly- ntil then the otpts #ill not !e adjsted to its ma5imm le/els0

G) The main important "eatre o""ered !y this chip is /arying the dty cycle /ery linearly0 This can

!e done !y /arying the /oltage at compensation pin throgh a potential di/iding net#or.

designed #ith a preset0


*=


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Althogh many s#itching techni4es can !e employed to implement a s#itched mode po#er

spply- either it is con/erter or in/erter- the "i5ed "re4ency 38M system- a s4are #a/e plse is

normally generated to dri/e the s#itching transistor MOS9ETS ON or O990 (y /arying the

#idth o" the plse- the condction time o" the MOS9ET is accordingly increased or decreased-

ths reglating the otpt /oltage0 The 38M control circit may !e single ended- capa!le o"

dri/ing a single MOS9ET con/erter- sch as 9ly !ac. or "or#ard0 I" t#o or more MOS9ETS

ha/e to !e dri/en- as #ith hal"B!ridge or "llB!ridge circits- a dal channel 38M circit is

necessary0 In this project #or. dal in/erted otpts are ta.en "rom the 38M I%- so that the

dri/e stage is designed in pshBpll con"igration #ith t#o po#er Mos"ets0

*) Genera< $e2crition of an Inte9rated P4M contro


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Fi9ure +

An opBamp compares the "eed !ac. signal "rom the otpt o" the po#er spply to a "i5ed

re"erence /oltage &'Bre")0 The error signal is ampli"ied and "ed in to the in/erting inpt o" a

comparator0 The nonBin/erting inpt o" the comparator accepts a sa#Btooth #a/e"orm #ith a

linear slope- generated !y a "i5ed "re4ency oscillator0 The oscillator otpt is also sed to toggle

a "lipB"lop- prodcing s4are #a/e otpts C and C0

The comparator s4are #a/e otpt and the 9lipB9lop otpts are !oth sed to dri/e the AN7

gates- ena!ling each otpt #hen !oth inpts to the gate are high0 The reslt is a /aria!le dty

cycle plse train at channels A and (0 In the a!o/e "igre sho#s the otpt plse #idth is

modlated #hen the error signal changes its amplitde- as detected !y the doted lines0 Normally

the otpts o" the 38M controller are e5ternally !""ered to dri/e the main po#er s#itching

po#er MOS9ETS0 This type o" circit may !e sed to dri/e t#o transistors MOS9ETS or a

single Transistor MOS9ET0 The merits o" a 38M controller are proB"ond- inclding the

programma!le "i5ed "re4ency oscillator- Linear 38M section #ith dty cycle "rom to *percent- adjsta!le dead time to pre/ent otpt transistor or MOS9ET simltaneos condction-

and a!o/e all simplicity- relia!ility- and cost e""ecti/eness0 The 38M control circit is I% :;2?-

#hich #as designed to !ecome the indstry standard0 These 38M controllers are the heart "or

the complete s#itching po#er spply design and may !e sed e4ally #ell in single ended or

dal channel applications0 The 38M comparator pro/ides a means "or the error ampli"ier to


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adjst the otpt plse #idth "rom the ma5imm percent on time- esta!lished !y the deadBtime

control inpt- do#n to ero- as the /oltage at the "eed !ac. /aries "rom 0;' to :0;'0 The error

ampli"ier otpts are acti/e high0 8ith this con"igration- the ampli"ier that demands minimm

otpt on time dominates control o" the loop0

*+ The fo


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The 38M latch insres- "reedom "rom mltiple plsing #ithin a period- e/en in noisy

en/ironments in addition- the shtdo#n circit "eeds directly to this latch- #hich #ill disa!le the

otpts #ithin 2 n0 sec0 o" acti/ation0 The crrent limit ampli"ier is a #ideB!and- high gain

ampli"ier- #hich is se"l "or either linear or plse !y plse crrent limiting in the grond or

po#er spply lines0 Its threshold is set at 2m/0 An nder /oltage loc.ot #ill disa!le the

internal circitry- e5cept the re"erence- ntil the inpt /oltage is ='0 This action holds stand !y

crrent lo# ntil trn on- simpli"ies the design o" lo# po#er- o"" line s#itchers0 These are the

ad/antages o" this /ersatile controller- there !y this can !e sed in a /ariety o" Isolated or nonB

isolated s#itching po#er spplies li.e in/erters or con/erters0 Hence- in this project #or.- this

controller is selected "or sage and the in/erter is designed sing this 38M controller0

The !asic concept o" plse #idth Modlation is gi/en !elo#J In the case o" opBamp- #hen

it is con"igred in open loop con"igration- the otpt #ill go to either ' sator D' sat de to its

high gain0 The s#itching o" ' satand D' satis- #hene/er the in/erting inpt is slightly mo/e

than NonBin/erting inpt /oltage- the otpt #ill !e in D' sat0i0e0- i" in/erting inpt dominates

NonBin/erting inpt- immediately the otpt #ill !e D' sat0 The ' sat#ill !e ' P *0;'0 Similarly-

i" the nonBin/erting /oltage is slightly more o/er the in/erting inpt /oltage- the otpt /oltage

#ill !e ' sat0 Ths- the otpt #ill !e only either ' sator D' sat0 No# #e #ill gi/e RAM3 or

sa#Btooth /oltage to the nonBin/erting inpt and the "eed!ac. or some /aria!le 7% /oltage #ill

!e gi/en to the in/erting inpt and #e #ill see ho# the otpt /oltage changes0 There !y the

otpt plse #idth modlation ta.es place depending pon the "eed !ac. /oltage0 These are !est

descri!ed #ith the #a/e"orms- #hich are gi/en !elo#0

Fi9ure 5


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As #e see the otpt- its on o"" periods is changing e/ery cycle depending p on the "eed

!ac. /oltage0 This concept is called plse #idth Modlation0 Also this concept is called dty

cycle /ariation0 7ty cycle is e4als to

*5 The fo


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The crrent limit ampli"ier is not sed at present- hence are connected to grond0 The

"re4ency o" the internal Oscillator is adjsted #ith RTand %T0 The Ramp generator is internally

connected inside the I% to the plse #idth Modlator0 9or details related to the internal details

o" the I%- it #as descri!ed in the %hapter Hard#are details0 To shtdo#n the I%- i0e0- to disa!le

the 38M otpt- sch as e5cess crrent dra#n !y load- the high signal to shtdo#n pin disa!les

the otpt- and there!y in/erter is protected "rom o/erload0 The !ilt in 38M generator- the

complementary C and C otpt "rom the internal 9lipB9lop and passes throgh internal NOR

gates cloc.ed !y the internal Oscillator0 These otpts are at ;H "re4ency &appro5imately)

38M otpt- are "rther ampli"ied sing class ( pshBpll stages0 The 3in 0> compensation

inpt is connected #ith so"t start circit0 This ma.es the 38M reglator to generate the otpt-

#hen the s#itch ON the nit- slo#ly- there !y it a/oids "alse triggering o" the protection

circits0 The time constant R% is designed #ith =26 5 *M9 K =2m sec0 To redce this delay a

&%ompensation 3in) otpt dty cycle can !e changed-

"or this prpose *6 3ot &/aria!le resistor) is connected !et#een 3in NO0> and grond0 (y

/arying the resistance re"erence /oltage at compensation pin also can !e /aried /ery linearly0

Hence !y /arying dty cycle otpt /oltage can !e controlled0

** $e2crition a/out drie 2ta9e

As descri!ed in pre/ios chapters- the dri/e stage is con"igred as pshBpll ampli"ier0 The

main prpose o" this ampli"ier is to ampli"y the /oltage and crrent le/els to the re4ired le/elJ

the re4ired le/el is to dri/e a


25/54


In a class ( pshBpll ampli"ier consists o" t#o identical dri/e stages at otpt circitry-

designed #ith po#er mos"ets dri/es the main trans"ormer0 These mos"ets are e5cited #ith e4al

!t opposite &*= degrees ot o" phase) /oltages "rom the inpt signal0 8hen operated in this

manner- one o" the mos"et ampli"ies the positi/e hal" cycles o" the signal /oltage #hile the other

mos"et ampli"ies the negati/e hal" cycles0 The ampli"ied hal" cycles are then com!ined in the

otpt trans"ormer in sch a manner as to prodce an ampli"ied reprodction o" the inpt /oltage

and crrent0 In actal practice- the t#o mos"ets are s#itched in a se4ence one a"ter another

according to the !iasing signals prodced !y the oscillator0 This a/oids crosso/er distortion0 The

mos"ets are condcted one a"ter another according to the time period- !ased on this "re4ency

prodced !y the oscillator- a gap !et#een the time #hen one mos"et shts o"" and the other is

trned on and this prodces a clipping e""ect on the otpt /oltage0 In this condition otpt is

distorted- this type o" distortion is called crosso/er distortion0

*6 The fo


26/54


other is negati/e !y an e4al amont0 The ad/antage o" pshBpll ampli"ier is it #ill eliminate

e/en harmonics0 The "act that the otpt crrent contains noBe/enBharmonic terms means that the

pshBpll possesses Hal" #a/e or mirror symmetry in addition to the ero a5is symmetry0

(ecase no e/en harmonics are present in the otpt o" a pshBpll ampli"ier- sch a circit #ill

gi/e more otpt per acti/e de/ice "or a gi/en amont o" distortion0 9or the same reason- the

pshBpll arrangement is sed to o!tain less distortion "or a gi/en po#er otpt per MOS9ET0

Another ad/antage o" pshBpll arrangement is that the 7% components o" the collector crrent

oppose each other magnetically in the trans"ormer core0 This eliminates any tendency to#ard

core satration and conse4ent NonBlinear distortion that might arise "rom the cr/atre o" the

trans"ormer magnetiation cr/e0 Another ad/antage is e""ects o" ripple /oltages that may !e

contained in the po#er spply !ecase o" inade4ate "iltering #ill !e !alanced ot0

The ad/antage o" sing po#er MOS9ETS- #hen compared #ith !ipolar po#er transistors-

!ecase o" its inpt high impedance No load crrent can !e redced and e""iciency can !e

increased0


2


27/54


6 !OLAR ENERGY AN O.ER .IE4

In todayQs climate o" gro#ing energy needs and increasing en/ironmental concern-

alternati/es to the se o" nonBrene#a!le and pollting "ossil "els ha/e to !e in/estigated0 One

sch alternati/e is solar energy0 Solar energy is 4ite simply the energy prodced directly !y the

sn and collected else#here- normally the Earth0 The sn creates its energy throgh a

thermonclear process that con/erts a!ot


28/54


nits0 The three types o" collectors are "latBplate collectors- "ocsing collectors- and passi/e

collectors0

9latBplate collectors are the more commonly sed type o" collector today0 They are arrays

o" solar panels arranged in a simple plane0 They can !e o" nearly any sie- and ha/e an otpt

that is directly related to a "e# /aria!les inclding sie- "acing- and cleanliness0 These /aria!les

all a""ect the amont o" radiation that "alls on the collector0 O"ten these collector panels ha/e

atomated machinery that .eeps them "acing the sn0 The additional energy they ta.e in de to

the correction o" "acing more than compensates "or the energy needed to dri/e the e5tra

machinery0

9ocsing collectors are essentially "latBplane collectors #ith optical de/ices arranged to

ma5imie the radiation "alling on the "ocs o" the collector0 These are crrently sed only in a"e# scattered areas0 Solar "rnaces are e5amples o" this type o" collector0 Althogh they can

prodce "ar greater amonts o" energy at a single point than the "latBplane collectors can- they

lose some o" the radiation that the "latBplane panels do not0 Radiation re"lected o"" the grond

#ill !e sed !y "latBplane panels !t sally #ill !e ignored !y "ocsing collectors &in sno#

co/ered regions- this re"lected radiation can !e signi"icant)0 One other pro!lem #ith "ocsing

collectors in general is de to temperatre0 The "ragile silicon components that a!sor! the

incoming radiation lose e""iciency at high temperatres- and i" they get too hot they can e/en !e

permanently damaged0 The "ocsing collectors !y their /ery natre can create mch higher

temperatres and need more sa"egards to protect their silicon components0

Solar energy is o"ten sed to directly heat a hose or !ilding0 Heating a !ilding re4ires

mch more energy than heating a !ildingQs #ater- so mch larger panels are necessary0

Generally a !ilding that is heated !y solar po#er #ill ha/e its #ater heated !y solar po#er as

#ell0 The type o" storage "acility most o"ten sed "or sch large solar heaters is the heatBo"B"sion

storage nit- !t other .inds &sch as the pac.ed !ed or hot #ater tan.) can !e sed as #ell0 This

application o" solar po#er is less common than the t#o mentioned a!o/e- !ecase o" the cost o"

the large panels and storage system re4ired to ma.e it #or.0 O"ten i" an entire !ilding is heated

!y solar po#er- passi/e collectors are sed in addition to one o" the other t#o types0 3assi/e

collectors #ill generally !e an integral part o" the !ilding itsel"- so !ildings ta.ing ad/antage

o" passi/e collectors mst !e created #ith solar heating in mind0


2=


29/54


These passi/e collectors can ta.e a "e# di""erent "orms0 The most !asic type is the

incidental heat trap0 The idea !ehind the heat trap is "airly simple0 Allo# the ma5imm amont

o" light possi!le inside throgh a #indo# &The #indo# shold !e "acing to#ards the e4ator "or

this to !e achie/ed) and allo# it to "all on a "loor made o" stone or another heat holding material0

7ring the day- the area #ill stay cool as the "loor a!sor!s most o" the heat- and at night- the area

#ill stay #arm as the stone reBemits the heat it a!sor!ed dring the day0

Another major "orm o" passi/e collector is thermosyphoning #alls andor roo"0 8ith this

passi/e collector- the heat normally a!sor!ed and #asted in the #alls and roo" is reBroted into

the area that needs to !e heated0

Solar energy can !e sed "or other things !esides heating0 It may seem strange- !t one o"

the most common ses o" solar energy today is cooling0 Solar cooling is "ar more e5pensi/e than

solar heating- so it is almost ne/er seen in pri/ate homes0 Solar energy is sed to cool things !y

phase changing a li4id to gas throgh heat- and then "orcing the gas into a lo#er pressre

cham!er0 The temperatre o" a gas is related to the pressre containing it- and all other things

!eing held e4al- the same gas nder a lo#er pressre #ill ha/e a lo#er temperatre0 This cool

gas #ill !e sed to a!sor! heat "rom the area o" interest and then !e "orced into a region o" higher

pressre #here the e5cess heat #ill !e lost to the otside #orld0 The net e""ect is that o" a pmp

mo/ing heat "rom one area into another- and the "irst is accordingly cooled0

(esides !eing sed "or heating and cooling- solar energy can !e directly con/erted to

electricity0 Most o" or tools are designed to !e dri/en !y electricity- so i" yo can create

electricity throgh solar po#er- yo can rn almost anything #ith solar po#er0 The solar

collectors that con/ert radiation into electricity can !e either "latBplane collectors or "ocsing

collectors- and the silicon components o" these collectors are photo/oltaic cells0

3hoto/oltaic cells- !y their /ery natre- con/ert radiation to electricity0 This phenomenon

has !een .no#n "or #ell o/er hal" a centry- !t ntil recently the amonts o" electricity

generated #ere good "or little more than measring radiation intensity0 Most o" the photo/oltaic

cells on the mar.et today operate at an e""iciency o" less than *;J that is- o" all the radiation

that "alls pon them- less than *; o" it is con/erted to electricity0 The ma5imm theoretical

e""iciency "or a photo/oltaic cell is only :20:- !t at this e""iciency- solar electricity is /ery


2>


30/54


economical0 Most o" or other "orms o" electricity generation are at a lo#er e""iciency than this0

1n"ortnately- reality still lags !ehind theory and a *; e""iciency is not sally considered

economical !y most po#er companies- e/en i" it is "ine "or toys and poc.et calclators0 Hope "or

!l. solar electricity shold not !e a!andoned- ho#e/er- "or recent scienti"ic ad/ances ha/e

created a solar cell #ith an e""iciency o" 2=02 e""iciency in the la!oratory0 This type o" cell has

yet to !e "ield tested0 I" it maintains its e""iciency in the ncontrolled en/ironment o" the otside

#orld- and i" it does not ha/e a tendency to !rea. do#n- it #ill !e economical "or po#er

companies to !ild solar po#er "acilities a"ter all0

O" the main types o" energy sage- the least sited to solar po#er is transportation0 8hile

large- relati/ely slo# /ehicles li.e ships cold po#er themsel/es #ith large on!oard solar panels-

small constantly trning /ehicles li.e cars cold not0 The only possi!le #ay a car cold !ecompletely solar po#ered #old !e throgh the se o" !attery that #as charged !y solar po#er at

some stationary point and then later loaded into the car0 Electric cars that are partially po#ered

!y solar energy are a/aila!le no#- !t it is nli.ely that solar po#er #ill pro/ide the #orldQs

transportation costs in the near "tre0

Solar po#er has t#o !ig ad/antages o/er "ossil "els0 The "irst is in the "act that it is

rene#a!leJ it is ne/er going to rn ot0 The second is its e""ect on the en/ironment0 8hile the

!rning o" "ossil "els introdces many harm"l polltants into the atmosphere and contri!tes to

en/ironmental pro!lems li.e glo!al #arming and acid rain- solar energy is completely nonB

pollting0 8hile many acres o" land mst !e destroyed to "eed a "ossil "el energy plant its

re4ired "el- the only land that mst !e destroyed "or a solar energy plant is the land that it

stands on0 Indeed- i" a solar energy system #as incorporated into e/ery !siness and d#elling- no

land #old ha/e to !e destroyed in the name o" energy0 This a!ility to decentralie solar energy

is something that "ossil "el !rning cannot match0

As the primary element o" constrction o" solar panels- silicon- is the second most

common element on the planet- there is /ery little en/ironmental distr!ance cased !y the

creation o" solar panels0 In "act- solar energy only cases en/ironmental disrption i" it is

centralied and prodced on a gigantic scale0 Solar po#er certainly can !e prodced on a

gigantic scale- too0


:


31/54


Sppose that o" the ?0;5**@.8h per annm that is sed !y the earth to e/aporate #ater

"rom the oceans #e #ere to ac4ire jst 0* or ?0;5* *?.8h per annm0 7i/iding !y the hors

in the year gi/es a continos yield o" 20>5**.80 This #old spply 20? .8 to *20* !illion

people0

This translates to roghly the amont o" energy sed today !y the a/erage American

a/aila!le to o/er t#el/e !illion people0 Since this is greater than the estimated carrying capacity

o" the Earth- this #old !e enogh energy to spply the entire planet regardless o" the

poplation0

1n"ortnately- at this scale- the prodction o" solar energy #old ha/e some

npredicta!le negati/e en/ironmental e""ects0 I" all the solar collectors #ere placed in one or jst

a "e# areas- they #old pro!a!ly ha/e large e""ects on the local en/ironment- and possi!ly ha/elarge e""ects on the #orld en/ironment0 E/erything "rom changes in local rain conditions to

another Ice Age has !een predicted as a reslt o" prodcing solar energy on this scale0 The

pro!lem lies in the change o" temperatre and hmidity near a solar panelJ i" the energy

prodcing panels are .ept nonBcentralied- they shold not create the same local- mass

temperatre change that cold ha/e sch !ad e""ects on the en/ironment0

O" all the energy sorces a/aila!le- solar has perhaps the most promise0 Nmerically- it is

capa!le o" prodcing the ra# po#er re4ired to satis"y the entire planetQs energy needs0

En/ironmentally- it is one o" the least destrcti/e o" all the sorces o" energy0 3ractically- it can

!e adjsted to po#er nearly e/erything e5cept transportation #ith /ery little adjstment- and

e/en transportation #ith some modest modi"ications to the crrent general system o" tra/el0

%learly- solar energy is a resorce o" the "tre0

6) Introduction to hotoo


32/54


Solar cells are typically com!ined into modles that hold a!ot ? cellsJ a!ot * o"

these modles are monted in 3' arraysthat can measre p to se/eral meters on a side0 These

flat-plate3' arrays can !e monted at a "i5ed angle "acing soth- or they can !e monted on a

trac.ing de/ice that "ollo#s the sn- allo#ing them to captre the most snlight o/er the corse

o" a day0 A!ot * to 2 3' arrays can pro/ide enogh po#er "or a hoseholdJ "or large electric

tility or indstrial applications- hndreds o" arrays can !e interconnected to "orm a single- large

3' system0

Thin "ilm solar cells se layers o" semicondctor materials only a "e# micrometers thic.0

Thin "ilm technology has made it possi!le "or solar cells to no# do!le as roo"top shingles- roo"

tiles- !ilding "acades- or the glaing "or s.ylights or atria0 The solar cell /ersion o" items sch as

shingles o""ers the same protection and dra!ility as ordinary asphalt shingles0

6+ HO4 A !OLAR PANEL 4OR-!

Solar 3anels dra# energy "rom the sn that is con/erted to electricity to recharge the

!attery0 The panel is at its ma5imm e""ecti/eness dring hors o" pea. snlight and at the other

e5treme- ma.es no contri!tion at night0 In the space o" a "e# sn hors- a panel can pro/ide

enogh energy to .eep the !attery charged

A photoB/oltaic &3') cell trns snlight directly into electricity0 Normally the cells are

connected together to "orm 3' modles- #hich can !e monted on yor roo" to gi/e yo yor

o#n mini po#er station0

The main application o" 3' in Scotland is to pro/ide some electricity "or !ildings- #hich

dont ha/e mains electricity- spply0 That incldes remote hoses- ca!ins- !oats and cara/ans0 In

that sitation- 3' electricity can !e more attracti/e than the alternati/e o" a diesel or petrol

generator0 Sometimes 3' can !e com!ined #ith #ind po#er0 That can redce the amont o"!attery capacity needed "or all o""Bgrid applications0 I" yo #ish to rn normal electrical

appliances- yo #ill also need a de/ice called an in/ertor #hich con/erts the !attery lo# /oltage

7% &direct crrent) to the normal 2:' A% &alternating crrent) #hich these appliances need0


:2


33/54


It is possi!le to ha/e a 3' system on d#ellings #hich ha/e a mains po#er spply0 In that

case- no !attery is needed and the direct crrent &7%) spplied !y the 3' can !e changed to the

alternating crrent &A%) o" the mains- so the t#o systems can !e interconnected0 I" yor 3' is

generating more electricity than yo need- then yo can e5port the srpls to the gridmains-

thogh yo normally #ill not earn as mch as yo pay to !y it0 8hen electrical needs are

greater than yor3' spply- then yo !y "rom the mains- as normal0

65 ELEMENT! OF THE !UN

The sn is a large sphere and its chemical composition is mainly Hydrogen #ith less

amont o" Helim0 Energy is generated in its interior throgh the nclear "sion o" Hydrogen

and Helim at a temperatre a!ot *; million 6el/ins0 The energy "inds its #ay to the sr"ace

and e/entally emitted into space primarily in the "orm o" electromagnetic radiation0 The

sr"ace o" the sn the photosphere is actally- a transition region in #hich the density "alls o"

rapidly0 As #e mo/e "rom the interior o" the sn to the oter part o" the photosphere- #e pass

"rom an optically opa4e medim to a relati/ely transparent one0 9rther more the temperatre

"alls to appro5imately


34/54


Fi9ure 8

The electromagnetic radiation emitted !y the sn co/ers a /ery large range o"

#a/elengths- "rom radio #a/es throgh the in"rared- /isi!le and ltra/iolet to BRays and

Gamma Rays0 Ho#e/er- >> o" the energy o" solar radiation id contained #ith in the

#a/elength !and "rom 0*; to ? Microns #ith a ma5imm at a!ot 0; Microns0 Roghly one

hal" o" the radiation lies in the /isi!le region o" the spectrm !et#een 0:= and 0@@ Microns and

the reminder in the in/isi!le ltra/iolet and in"rared regions0

The sns diameter is appro5imately *0:> *>meters #hile that o" the earth is *02@

*@meters0 The total Mass o" the Sn is *0>> *:.gs0 The mean distance !et#een the sn

and the earth is *0; *** meters0 The Sn s!tends an angle o" :2 mintes at the earths

Sr"ace0

6* E1TRA TERRE!TIAL !OLAR RA$IATION

There are t#o motions o" the earth the re/oltion o" the earth arond the sn and the

rotation o" the earth a!ot its a5is0 The earth re/ol/es in an elliptical or!it #ith Sn at one "ocs

o" the ellipse- at a mean distance o" *0; *=.ms #ith a /ariation o" *0@0

The "ollo#ing is the "igre sho#s- schematic o" Sn D Earth relationship0


:?


35/54


Fi9ure (

$IA ? )5' 1 )&8D=

$i2tance ? )61)&:D= Aro0

The solar constant IS% is the total &o/erall #a/e length) solar Radio acti/e energy that

stri.es a nit area e5posed to perpendiclar rays o" the sn at the mean Sn D Earth distance0

The crrently accepted /ale o" the Solar constant is *:;: 2 #attsmtr S40 The e5tra

terrestrial radiation IO stri.ing the earth #a/es throghot the year- primarily!ecase o" the

change in the Sn earth distance- !t also de to Snspots- "lares and other random acti/ity o"

the Sn0 The /ariation de to the distance change can !e e5pressed

As IO &n) K IS% *0:? cos &:


36/54


8 $E!CRIPTION ABOUT IN.ERTER!

An inerteris an electrical de/ice that con/erts direct crrent&7%) toalternating crrent

&A%)J the con/erted A% can !e at any re4ired /oltage and "re4ency #ith the se o" appropriate

trans"ormers- s#itching- and control circits0

Static in/erters ha/e no mo/ing parts and are sed in a #ide range o" applications- "rom

small s#itching po#er sppliesin compters- to large electric tilityhighB/oltage direct crrent

applications that transport !l. po#er0 In/erters are commonly sed to spply A% po#er "rom

7% sorces sch as solar panelsor!atteries0

The electrical in/erter is a highBpo#er electronic oscillator0 It is so named !ecase early

mechanical A% to 7% con/erters #as made to #or. in re/erse- and ths #as Uin/ertedU- to

con/ert 7% to A%0 The in/erter per"orms the opposite "nction o" a recti"ier0 In this project

#or.- one amp otpt in/erter is designed to dri/e the ac motor0

An in/erter con/erts the 7% electricity "rom sorces sch as !atteries- solar panels- or

"el cells to A% electricity0 The electricity can !e at any re4ired /oltageJ in particlar it can

operate A% e4ipment designed "or mains operation- or recti"ied to prodce 7% at any desired

/oltage0 Grid tie in/erterscan "eed energy !ac. into the distri!tion net#or. !ecase they

prodce alternating crrent #ith the same #a/e shape and "re4ency as spplied !y the

distri!tion system0 They can also s#itch o"" atomatically in the e/ent o" a !lac.ot0MicroB

in/erters con/ert direct crrent "rom indi/idal solar panels into alternating crrent "or the

electric grid0

8) Uninterruti/


37/54


in/erter can !e pro/ided "rom main A% po#er0 Since an in/erter is the .ey component- /aria!leB

"re4ency dri/es are sometimes called in/erter dri/es or jst in/erters0

85 The 9enera< ca2e

Atrans"ormerallo#s A% po#er to !e con/erted to any desired /oltage- !t at the same

"re4ency0 In/erters- pls recti"iers "or 7%- can !e designed to con/ert "rom any /oltage- A% or

7%- to any other /oltage- also A% or 7%- at any desired "re4ency0 The otpt po#er can ne/er

e5ceed the inpt po#er- !t e""iciencies can !e high- #ith a small proportion o" the po#er

dissipated as #aste heat0

8* Ba2ic de2i9n2

In one simple in/erter circit- 7% po#er is connected to a trans"ormerthrogh the centre tapo" the primary #inding0 A s#itch is rapidly s#itched !ac. and "orth to allo# crrent to "lo# !ac.

to the 7% sorce "ollo#ing t#o alternate paths throgh one end o" the primary #inding and then

the other0 The alternation o" the direction o" crrent in the primary #inding o" the trans"ormer

prodces alternating crrent&A%) in the secondary circit0

The electromechanical /ersion o" the s#itching de/ice incldes t#o stationary contacts and

a spring spported mo/ing contact0 The spring holds the mo/a!le contact against one o" the

stationary contacts and an electromagnet plls the mo/a!le contact to the opposite stationary

contact0 The crrent in the electromagnet is interrpted !y the action o" the s#itch so that the

s#itch continally s#itches rapidly !ac. and "orth0 This type o" electromechanical in/erter

s#itch- called a /i!ratoror !er- #as once sed in /acm t!e atomo!ile radios0 A similar

mechanism has !een sed in door !ells- !ers and tattoo gns0

86 Outut 3aefor=2

The s#itch in the simple in/erter descri!ed a!o/e prodces a s4are /oltage #a/e"ormas

opposed to the sinsoidal#a/e"orm that is the sal #a/e"orm o" an A% po#er spply0 1sing

9orier analysis- periodic#a/e"orms are represented as the sm o" an in"inite series o" sine

#a/es0 The sine #a/e that has the same "re4ency as the original #a/e"orm is called the

"ndamental component0 The other sine #a/es- called harmonicsthat are inclded in the series

ha/e "re4encies that are integral mltiples o" the "ndamental "re4ency0


:@
http://en.wikipedia.org/wiki/Transformerhttp://en.wikipedia.org/wiki/Transformerhttp://en.wikipedia.org/wiki/Alternating_currenthttp://en.wikipedia.org/wiki/Vibrator_(electronic)http://en.wikipedia.org/wiki/Vacuum_tubehttp://en.wikipedia.org/wiki/Tattoo_gunhttp://en.wikipedia.org/wiki/Waveformhttp://en.wikipedia.org/wiki/Sine_wavehttp://en.wikipedia.org/wiki/Fourier_analysishttp://en.wikipedia.org/wiki/Periodic_functionhttp://en.wikipedia.org/wiki/Frequencyhttp://en.wikipedia.org/wiki/Transformerhttp://en.wikipedia.org/wiki/Transformerhttp://en.wikipedia.org/wiki/Alternating_currenthttp://en.wikipedia.org/wiki/Vibrator_(electronic)http://en.wikipedia.org/wiki/Vacuum_tubehttp://en.wikipedia.org/wiki/Tattoo_gunhttp://en.wikipedia.org/wiki/Waveformhttp://en.wikipedia.org/wiki/Sine_wavehttp://en.wikipedia.org/wiki/Fourier_analysishttp://en.wikipedia.org/wiki/Periodic_functionhttp://en.wikipedia.org/wiki/Frequency


38/54


The 4ality o" otpt #a/e"orm that is needed "rom an in/erter depends on the

characteristics o" the connected load0 Some loads need a nearly per"ect sine #a/e /oltage spply

in order to #or. properly0 Other loads may #or. 4ite #ell #ith a s4are #a/e /oltage0

88 Adanced de2i9n2

HB!ridge in/erter circit designed #ith transistor s#itches and anti parallel diodes0 There

are many di""erent po#er circit topologies and control strategies sed in in/erter designs0

7i""erent design approaches address /arios isses that may !e more or less important depending

on the #ay that the in/erter is intended to !e sed0 The isse o" #a/e"orm 4ality can !e

addressed in many #ays0 %apacitors and indctorscan !e sed to "ilter the #a/e"orm0 I" the

design incldes a trans"ormer- "iltering can !e applied to the primary or the secondary side o" the

trans"ormer or to !oth sides0 Lo#Bpass "iltersare applied to allo# the "ndamental component o"

the #a/e"orm to pass to the otpt #hile limiting the passage o" the harmonic components0 I" the

in/erter is designed to pro/ide po#er at a "i5ed "re4ency- a resonant"ilter can !e sed0 9or an

adjsta!le "re4ency in/erter- the "ilter mst !e tned to a "re4ency that is a!o/e the ma5imm

"ndamental "re4ency0

Since most loads contain indctance- "eed!ac. recti"iersor anti paralleldiodesare o"ten

connected across each semicondctors#itch to pro/ide a path "or the pea. indcti/e load crrent

#hen the s#itch is trned o""0 The anti parallel diodes are some#hat similar to the "ree#heeling

diodessed in A%7% con/erter circits0

Modlating- or reglating the #idth o" a s4areB#a/e plse is o"ten sed as a method o"

reglating or adjsting an in/erterQs otpt /oltage0 8hen /oltage control is not re4ired- a "i5ed

plse #idth can !e selected to redce or eliminate selected harmonics0 Harmonic elimination

techni4es are generally applied to the lo#est harmonics !ecase "iltering is more e""ecti/e at

high "re4encies than at lo# "re4encies0 Mltiple plseB#idth or carrier !ased 38M control

schemes prodce #a/e"orms that are composed o" many narro# plses0 The "re4encyrepresented !y the nm!er o" narro# plses per second is called the s#itching "re4ency or

carrier "re4ency0 These control schemes are o"ten sed in /aria!leB"re4ency motor control

in/erters !ecase they allo# a #ide range o" otpt /oltage and "re4ency adjstment #hile also

impro/ing the 4ality o" the #a/e"orm0


:=
http://en.wikipedia.org/wiki/H-bridgehttp://en.wikipedia.org/wiki/Topology_(electronics)http://en.wikipedia.org/wiki/Control_systemhttp://en.wikipedia.org/wiki/Capacitorhttp://en.wikipedia.org/wiki/Inductorhttp://en.wikipedia.org/wiki/Electronic_filterhttp://en.wikipedia.org/wiki/Low-pass_filtershttp://en.wikipedia.org/wiki/Resonancehttp://en.wikipedia.org/wiki/Rectifierhttp://en.wikipedia.org/wiki/Antiparallelhttp://en.wikipedia.org/wiki/Diodeshttp://en.wikipedia.org/wiki/Semiconductorhttp://en.wikipedia.org/wiki/Flyback_diodehttp://en.wikipedia.org/wiki/Flyback_diodehttp://en.wikipedia.org/wiki/H-bridgehttp://en.wikipedia.org/wiki/Topology_(electronics)http://en.wikipedia.org/wiki/Control_systemhttp://en.wikipedia.org/wiki/Capacitorhttp://en.wikipedia.org/wiki/Inductorhttp://en.wikipedia.org/wiki/Electronic_filterhttp://en.wikipedia.org/wiki/Low-pass_filtershttp://en.wikipedia.org/wiki/Resonancehttp://en.wikipedia.org/wiki/Rectifierhttp://en.wikipedia.org/wiki/Antiparallelhttp://en.wikipedia.org/wiki/Diodeshttp://en.wikipedia.org/wiki/Semiconductorhttp://en.wikipedia.org/wiki/Flyback_diodehttp://en.wikipedia.org/wiki/Flyback_diode


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Mltile/el in/erters pro/ide another approach to harmonic cancellation0 Mltile/el in/erters

pro/ide an otpt #a/e"orm that e5hi!its mltiple steps at se/eral /oltage le/els0 9or e5ample- it

is possi!le to prodce a more sinsoidal #a/e !y ha/ing splitBrail direct crrentinpts at t#o

/oltages- or positi/e and negati/e inpts #ith a central grond0 (y connecting the in/erter otpt

terminals in se4ence !et#een the positi/e rail and grond- the positi/e rail and the negati/e rail-

the grond rail and the negati/e rail- then !oth to the grond rail- a stepped #a/e"orm is

generated at the in/erter otpt0 This is an e5ample o" a three le/el in/erter the t#o /oltages and

grond0

8( Three ha2e inerter2

Fi9ure :

:Bphase in/erter #ith connected load

ThreeBphasein/erters are sed "or /aria!leB"re4ency dri/eapplications and "or high

po#er applications sch as H'7%po#er transmission0 A !asic threeBphase in/erter consists o"

three singleBphase in/erter s#itches each connected to one o" the three load terminals0 9or the

most !asic control scheme- the operation o" the three s#itches is coordinated so that one s#itch

operates at each


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( $E!CRIPTION ABOUT PO4ER MO!FET!

A Po3er MO!FETis a speci"ic type o" metal o5ide semicondctor "ieldBe""ect transistor

&MOS9ET) designed to handle large amonts o" po#er0 %ompared to the other po#er

semicondctor de/ices- its main ad/antages are high commtation speed and good e""iciency at

lo# /oltages0 It shares #ith the IG(T an isolated gate that ma.es it easy to dri/e0 It #as made

possi!le !y the e/oltion o" %MOStechnology- de/eloped "or man"actring Integrated circits

in the late *>@s0 The po#er MOS9ET shares its operating principle #ith its lo#Bpo#er

conterpart- the lateral MOS9ET0 The po#er MOS9ET is the most #idely sed lo#B/oltage

s#itch0 It can !e "ond in mostpo#er sppliesin/erters- 7% to 7% con/erters-and lo# /oltage

motor controllers0 In general this de/ice is sed "or ampli"ying or s#itching electronic signals0

The !asic principle o" the de/ice #as "irst proposed !y lis Edgar Lilien"eld in *>2;0 In

Mos"ets- a /oltage on the o5ideBinslated gate electrode can indce a condcting channel

!et#een the t#o other contacts called sorce and drain0 The channel can !e o" nBtypeor pBtype-

and is accordingly called an NMOS9ET or a 3MOS9ET &also commonly nMOS- pMOS)0 It is !y

"ar the most common transistorin !oth digitaland analogcircits- thogh the!ipolar jnction

transistor#as at one time mch more common0

The QmetalQ in the name is no# o"ten a misnomer!ecase the pre/iosly metal gate

material is no# o"ten a layer o" polysilicon &polycrystalline silicon)0 Alminmhad !een the

gate material ntil the mid *>@s- #hen polysilicon !ecame dominant- de to its capa!ility to

"orm sel"Baligned gates0 Metallic gates are regaining poplarity- since it is di""iclt to increase the

speed o" operation o" transistors #ithot metal gates0IG9ET is a related term meaning inslatedB

gate "ieldBe""ect transistor- and is almost synonymos #ith MOS9ET- thogh it can re"er to 9ETs

#ith a gate inslator that is not o5ide0 Another synonym is MIS9ET "or metalDinslatorD

semicondctor 9ET

1sally the semicondctoro" choice is silicon- !t some chip man"actrers- most nota!lyI(M- recently started sing a compond &mi5tre) o" silicon and germanim &SiGe) in MOS9ET

channels0 1n"ortnately- many semicondctors #ith !etter electrical properties than silicon- sch

as gallim arsenide- do not "orm good semicondctorBtoBinslator inter"aces- ths are not sita!le

"or Mos"ets0 Research contines on creating inslators #ith accepta!le electrical characteristics

on other semicondctor material0 In order to o/ercome po#er consmption increase de to gate


?
http://en.wikipedia.org/wiki/MOSFEThttp://en.wikipedia.org/wiki/Power_semiconductor_devicehttp://en.wikipedia.org/wiki/Power_semiconductor_devicehttp://en.wikipedia.org/wiki/CMOShttp://en.wikipedia.org/wiki/Integrated_circuithttp://en.wikipedia.org/wiki/MOSFEThttp://en.wikipedia.org/wiki/Power_supplyhttp://en.wikipedia.org/wiki/DC_to_DC_converterhttp://en.wikipedia.org/wiki/Motor_controllerhttp://en.wikipedia.org/wiki/Signal_(electrical_engineering)http://en.wikipedia.org/wiki/Julius_Edgar_Lilienfeldhttp://en.wikipedia.org/wiki/Channel_(transistor)http://en.wikipedia.org/wiki/N-type_semiconductorhttp://en.wikipedia.org/wiki/P-type_semiconductorhttp://en.wikipedia.org/wiki/Transistorhttp://en.wikipedia.org/wiki/Digital_circuithttp://en.wikipedia.org/wiki/Analog_circuithttp://en.wikipedia.org/wiki/Bipolar_junction_transistorhttp://en.wikipedia.org/wiki/Bipolar_junction_transistorhttp://en.wikipedia.org/wiki/Misnomerhttp://en.wikipedia.org/wiki/Polysiliconhttp://en.wikipedia.org/wiki/Aluminiumhttp://en.wikipedia.org/wiki/Self-aligned_gatehttp://en.wikipedia.org/wiki/Metal_gatehttp://en.wikipedia.org/wiki/MISFEThttp://en.wikipedia.org/wiki/Semiconductorhttp://en.wikipedia.org/wiki/Siliconhttp://en.wikipedia.org/wiki/IBMhttp://en.wikipedia.org/wiki/Silicon_germaniumhttp://en.wikipedia.org/wiki/Gallium_arsenidehttp://en.wikipedia.org/wiki/MOSFEThttp://en.wikipedia.org/wiki/Power_semiconductor_devicehttp://en.wikipedia.org/wiki/Power_semiconductor_devicehttp://en.wikipedia.org/wiki/CMOShttp://en.wikipedia.org/wiki/Integrated_circuithttp://en.wikipedia.org/wiki/MOSFEThttp://en.wikipedia.org/wiki/Power_supplyhttp://en.wikipedia.org/wiki/DC_to_DC_converterhttp://en.wikipedia.org/wiki/Motor_controllerhttp://en.wikipedia.org/wiki/Signal_(electrical_engineering)http://en.wikipedia.org/wiki/Julius_Edgar_Lilienfeldhttp://en.wikipedia.org/wiki/Channel_(transistor)http://en.wikipedia.org/wiki/N-type_semiconductorhttp://en.wikipedia.org/wiki/P-type_semiconductorhttp://en.wikipedia.org/wiki/Transistorhttp://en.wikipedia.org/wiki/Digital_circuithttp://en.wikipedia.org/wiki/Analog_circuithttp://en.wikipedia.org/wiki/Bipolar_junction_transistorhttp://en.wikipedia.org/wiki/Bipolar_junction_transistorhttp://en.wikipedia.org/wiki/Misnomerhttp://en.wikipedia.org/wiki/Polysiliconhttp://en.wikipedia.org/wiki/Aluminiumhttp://en.wikipedia.org/wiki/Self-aligned_gatehttp://en.wikipedia.org/wiki/Metal_gatehttp://en.wikipedia.org/wiki/MISFEThttp://en.wikipedia.org/wiki/Semiconductorhttp://en.wikipedia.org/wiki/Siliconhttp://en.wikipedia.org/wiki/IBMhttp://en.wikipedia.org/wiki/Silicon_germaniumhttp://en.wikipedia.org/wiki/Gallium_arsenide


41/54


crrent lea.age- highBV dielectricreplaces silicon dio5ide "or the gate inslator- #hile metal gates

retrn !y replacingpoly silicon0

The gate is separated "rom the channel !y a thin inslating layer- traditionally o" silicon

dio5ide and later o" silicon o5ynitride0 Some companies ha/e started to introdce a highBV

dielectric metal gate com!ination in the ?; nanometer node0 8hen a /oltage is applied

!et#een the gate and !ody terminals- the electric "ield generated penetrates throgh the o5ide

and creates an alleged Uin/ersion layerU or UchannelU at the semicondctorBinslator inter"ace0

The in/ersion channel is o" the same type- 3Btype or NBtype- as the sorce and drain- ths it

pro/ides a channel throgh #hich crrent can pass0 'arying the /oltage !et#een the gate and

!ody modlates the condcti/ityo" this layer and allo#s controlling the crrent "lo# !et#een

drain and sorce0

() Circuit 2"=/o


42/54


Fi9ure '

9or the sym!ols in #hich the !l.- or !ody- terminal is sho#n- it is here sho#n

internally connected to the sorce0 This is a typical con"igration- !t !y no means the only

important con"igration0 In general- the MOS9ET is a "orBterminal de/ice- and in integrated

circits many o" the Mos"ets share a !ody connection- not necessarily connected to the sorce

terminals o" all the transistors0

(+ MO!FET oeration

9or the sym!ols in #hich the !l.- or !ody- terminal is sho#n- it is here sho#n internally

connected to the sorce0 This is a typical con"igration- !t !y no means the only important

con"igration0 In general- the MOS9ET is a "orBterminal de/ice- and in integrated circits many

o" the Mos"ets share a !ody connection- not necessarily connected to the sorce terminals o" all

the transistors0

Fi9ure )&


?2


43/54


(5 Meta


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Fi9ure )+

%ross section o" an NMOS #ith channel "ormed ON state

A metalDo5ideDsemicondctor "ieldBe""ect transistor &MOS9ET) is !ased on the modlation

o" charge concentration !y a MOS capacitance !et#een a /od"electrode and a 9ateelectrode

located a!o/e the !ody and inslated "rom all other de/ice regions !y a gate dielectric layer

#hich in the case o" a MOS9ET is an o5ide- sch as silicon dio5ide0 I" dielectrics other than an

o5ide sch as silicon dio5ide &o"ten re"erred to as o5ide) are employed the de/ice may !e

re"erred to as a metalDinslatorDsemicondctor 9ET &MIS9ET)0 %ompared to the MOS

capacitor- the MOS9ET incldes t#o additional terminals &2ourceand drain)- each connected to

indi/idal highly doped regions that are separated !y the !ody region0 These regions can !e

either p or n type- !t they mst !oth !e o" the same type- and o" opposite type to the !ody

region0 The sorce and drain &nli.e the !ody) are highly doped as signi"ied !y a QQ sign a"ter the

type o" doping0

I" the MOS9ET is an nBchannel or nMOS 9ET- then the sorce and drain are QnQ regions and

the !ody is a QpQ region0 As descri!ed a!o/e- #ith s""icient gate /oltage- a!o/e a threshold

/oltage /ale- electrons "rom the sorce &and possi!ly also the drain) enter the in/ersion layer or

n-channelat the inter"ace !et#een the p region and the o5ide0 This condcting channel e5tends

!et#een the sorce and the drain- and crrent is condcted throgh it #hen a /oltage is applied

!et#een sorce and drain0


??
http://en.wikipedia.org/wiki/MISFEThttp://en.wikipedia.org/wiki/Threshold_voltagehttp://en.wikipedia.org/wiki/Threshold_voltagehttp://en.wikipedia.org/wiki/File:N-channel_mosfet.JPGhttp://en.wikipedia.org/wiki/MISFEThttp://en.wikipedia.org/wiki/Threshold_voltagehttp://en.wikipedia.org/wiki/Threshold_voltage


45/54


: PO4ER !OURCE $E!CRIPTION

The system designed here tilies solar po#er0 As long as the solar energy is

a/aila!le- the !attery #ill !e charged at di""erent crrent ratings0 As the ot pt o" panel is/aria!le- it may not !e sta!le0 I" the Sn is !right- the panel can deli/er ma5imm ot pt crrent

o" =ma at arond *2'0

:) BATTERY

This de/ice can !e called as chemical /oltage sorceJ a chemical /oltage sorce is one o"

the most important sorces o" electrical energy0 It is a sel" contained /oltage sorce and does not

need any ot side energy0 8hen the !attery is discharged it is spposed to !e charged #ith

sita!le po#er sorce either "rom solar panel or "rom mains spply- i0e0 single phase

con/entional energy sorce0 The electrical energy spplied !y a chemical sorce o" /oltage is

prodced !y chemical action #ithin the sorce itsel"0 %hemical /oltage sorces normally e5ist in

the "orm o" !atteries and cells o" /arios types0 These !atteries are e5tensi/ely sed "or mo!ile

applications0

Here in this project #or. reBchargea!le storage !attery is sed0 As it is a prototype modle-

the !attery sed here can #ithstand "or one hor- !t "or real applications hea/y dty !attery can

!e sed "or long !ac.Bp0

(atteries are maintenance "ree sealed lead acid rechargea!le !atteries0 The !atteries are

ha/ing e5cellent economy sta!ility and sperior otpt0 'arios characteristics ha/e !een

impro/ed sch as lea. proo"- o/ercharging and o/er discharging0 This compact $ po#er"l

sealed leadBacid !attery #ith higher per"ormance can !e sed as a po#er sorce "or porta!le

instrments and also "or po#er !ac.p se0 (atteries are no# !eing sed in a #ide range o"

applications0

:+ CHARGING METHO$

These (atteries are maintenance "ree0 There is no need to add #ater0 (attery per"ormance

and ser/ice li"e are greatly a""ected !y the charging method0 There are /arios di""erent charging

methods constant /oltage charging- constant crrent charging- tapered crrent charging and


?;


46/54


some com!ination systems0 (atteries can !e charged !y any o" those methods0 Ho#e/er-

constant /oltage charging com!ined #ith limited crrent is recommended "or o!taining

ma5imm capacity and ser/ice li"e together #ith accepta!le recharge times and economy0 Here

the !attery is charged #ith constant /oltage sorce0

:5!OLAR ENERGY

In todayQs climate o" gro#ing energy needs and increasing en/ironmental concern-

alternati/es to the se o" nonBrene#a!le and pollting "ossil "els ha/e to !e in/estigated0 One

sch alternati/e is solar energy0 Solar energy is 4ite simply the energy prodced directly !y the

sn and collected #here re4ired0 The sn creates its energy throgh a thermonclear process

that con/erts a!ot


47/54


' $E!CRIPTION ABOUT !OLAR PANEL!

Solar photo/oltaic systems se solar energy to prodce electricity0 The term hotoo


48/54


') PHOTO.OLTAIC CELL!

3hoto/oltaic cells- #hich con/ert light directly into electricity- ha/e !ecome

commonplace on de/ices sch as calclators and #atches0 There are a nm!er o" technologies in

de/elopment #ith the aim o" ma.ing 3' more economic "or electrical po#er generation0 All se

semicondctor materials li.e those sed in silicon chips0

The heart o" a 3' cell is the inter"ace !et#een t#o di""erent types o" semicondctor0 8hen a

light photon hits a silicon atom in this region- it thro#s ot an electron0 The electron can tra/el

throgh the nBtype semicondctor to metal contacts on the sr"ace0 The hole le"t !y the a!sence

o" the electron tra/els in the opposite direction0 Once at the metal contact the electron "lo#s

throgh an electrical circit !ac. to meet p #ith a hole at the other contact0

As it "lo#s throgh the e5ternal circit- the electron does se"l #or.- li.e charging a

!attery- or operating an electrical appliance0 3hoto/oltaic systems ha/e !een redcing in cost-

and increasing in e""iciency in recent years0 The most e""icient commercially a/aila!le systems

can con/ert p to *


49/54


'+ O.ER.IE4 OF THE TECHNOLOGY

Snlight is composed o" photons containing energy #hich correspond to the di""erent

#a/elengths o" the solar spectrm0 8hen photons stri.e a 3' cell- their energy is trans"erred to

an electron in the semicondctor material o" the cell0 8ith this e5tra energy- the electron is then

a!le to escape "rom its normal position in the atom creating a UholeU- #hich #ill !ecome part o" a

crrent in an electrical circit0

A diode is "ormed #hen t#o layers o" semicondctor materials are doped so that one #ill

condct negati/e carriers and the other positi/e carriers0 8hen photons "all on these layers they

trans"er energy and momentm to charge carriers- #hich increase their potential energy !y an

amont depending on the diodeQs material properties0 (ecase o" their electrical properties- 3'

modles prodce direct crrent &7%) rather than alternating crrent &A%)0 In the simplest 3'

systems- 7% crrent is sed immediately in applications !t #here A% is re4iredJ an in/erter is

added to the system to con/ert 7% into A%0

The e""iciency o" the photo/oltaic con/ersion process #old !e a!ot =; i" each photon

cold trans"er all its energy into that o" charge carriers0 Ho#e/er- this is normally not the case as

any trans"er o" energy "rom photon to charge carrier can only !e o" the amont gi/en !y the

!andBgap o" the semicondctor material0 3hotons #ith energies !elo# the energy !andBgap o" the

material are lost "rom the photo/oltaic e""ect and con/erted into heat0 In addition- photons #ith

energies a!o/e the !andBgap trans"er no more than the !andBgap energy- and any e5cess energy is

lost0 In todayQs cells- !oth o" these e""ects indi/idally limit the theoretical e""iciency to ;0

%rrently- practical ma5imm e""iciencies are in the range o" *;B20 Ideally- 3' cells #old

consist o" material layers #ith di""erent !andBgaps- "or each photon to !e a!sor!ed e5actly #here

its energy matches the !andBgap energy0

The otpt "rom a 3' modle depends on the amont o" incident light and other "actorssch as temperatre and the cleanliness o" the cell sr"ace0 Modles are rated in terms o" their

pea. otpt &3ea. 8atts- or 83)- #hich is the ma5imm po#er that they #ill prodce gi/en

cali!rated solar inpt and operating conditions0 Ho#e/er- 3' cells can prodce se"l 4antities

o" po#er in less than ideal solar conditions


?>


50/54


)& $ATA !HEET

O3EN %IR%1IT

SOLAR 3ANEL 'OLTAGEB*>0@ '

LE7 1SAGEB0* A

1N7ER %HARGING

SOLAR 3ANEL O131TB*


51/54


Solar Energy is a rene#a!le "orm o" energy and tends to gi/e s large amont o" energy

and light0 Oil- on the other hand is not rene#a!le and also degrades the en/ironment0

Solar cells are /ery silent in their #or.ing and they are 4ite e""icient too-

Solar energy e4ipments do not emit any harm"l gases or radiations0 They are highly

ecoB"riendly0

Solar cells re4ire /ery less maintenance and they ha/e a long li"e too0

Thogh- the initial set p o" the solar panels is e5pensi/e- later on they trn ot to !e

highly cost e""ecti/e-


;*


52/54


)+ CONCLU!ION!

The project #or. ;!o


53/54


)5 0FUTURE !COPE

Solar po#er deals #ith the se o" solar radiation "or practical prposes0 It has !een

employed in order to decrease the car!on "ootprints "rom or en/ironment0 It is the !asic motor

o" all "orms o" energy generation methods0 It is "ree and clean to se0 This "orm o" energy isa/aila!le in a!ndance in or en/ironment0 The "ossil "els are also mere "roen solar po#er0

Solar energy has remained a necessary ingredient "or decades no#0 ItQs demand "or sage still

pre/ails0

It is mainly sed "or the domestic prposes these days0 !o


54/54


)6 REFERENCE!#

In order to select a sita!le topic "or the project- "e# !oo.s are re"erred0 The list is

as "ollo#s

*) 3o#er systems (y 0(0 G13TA

2) Solar Energy 1tiliation (y G070 Rai

:) 3o#er "rom the Sn D A practical gide to solar electricity

(y 7an %hiras

?) 8ind and solar po#er systems (y M.nd R0 3atil

;) Solar electricity hand !oo. (y Michael !o5#ell

Documents

UG - Mini Project - Solar Lightning System